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Additions to the NASA Aeronautics and Space Database as of 05/21/2009
20090017794 NASA Langley Research Center, Hampton, VA, United States
Description of the F-16XL Geometry and Computational Grids Used in CAWAPI
Boelens, O. J.; Badcock, K. J.; Gortz, S.; Morton, S.; Fritz, W.; Karman, S. L., Jr.; Michal, T.; Lamar, J. E.; [2009]; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 561581.02.08.07
Report No.(s): LF99-5900; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://dx.doi.org/10.2514/1.34852
The objective of the Cranked-Arrow Wing Aerodynamics Project International (CAWAPI) was to allow a comprehensive validation of Computational Fluid Dynamics methods against the CAWAP flight database. A major part of this work involved the generation of high-quality computational grids. Prior to the grid generation an IGES file containing the air-tight geometry of the F-16XL aircraft was generated by a cooperation of the CAWAPI partners. Based on this geometry description both structured and unstructured grids have been generated. The baseline structured (multi-block) grid (and a family of derived grids) has been generated by the National Aerospace Laboratory NLR. Although the algorithms used by NLR had become available just before CAWAPI and thus only a limited experience with their application to such a complex configuration had been gained, a grid of good quality was generated well within four weeks. This time compared favourably with that required to produce the unstructured grids in CAWAPI. The baseline all-tetrahedral and hybrid unstructured grids has been generated at NASA Langley Research Center and the USAFA, respectively. To provide more geometrical resolution, trimmed unstructured grids have been generated at EADS-MAS, the UTSimCenter, Boeing Phantom Works and KTH/FOI. All grids generated within the framework of CAWAPI will be discussed in the article. Both results obtained on the structured grids and the unstructured grids showed a significant improvement in agreement with flight test data in comparison with those obtained on the structured multi-block grid used during CAWAP.
Author
F-16 AIRCRAFT; SWEPT WINGS; AERODYNAMIC CHARACTERISTICS; AERODYNAMICS; COMPUTATIONAL FLUID DYNAMICS; GRID GENERATION (MATHEMATICS); AIRCRAFT DESIGN; COMPUTER AIDED DESIGN
20090017796 NASA Langley Research Center, Hampton, VA, United States
Overview of the Cranked-Arrow Wing Aerodynamics Project International
Obara, Clifford J.; Lamar, John E.; [2008}; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 122711.03.07.07.02.80
Report No.(s): LF99-7351; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090017796
http://dx.doi.org/10.2514/1.34957
This paper provides a brief history of the F-16XL-1 aircraft, its role in the High Speed Research program and how it was morphed into the Cranked Arrow Wing Aerodynamics Project. Various flight, wind-tunnel and Computational Fluid Dynamics data sets were generated as part of the project. These unique and open flight datasets for surface pressures, boundary-layer profiles and skin-friction distributions, along with surface flow data, are described and sample data comparisons given. This is followed by a description of how the project became internationalized to be known as Cranked Arrow Wing Aerodynamics Project International and is concluded by an introduction to the results of a four year computational predictive study of data collected at flight conditions by participating researchers.
Author
F-16 AIRCRAFT; ARROW WINGS; AERODYNAMICS; FLIGHT CONDITIONS; COMPUTATIONAL FLUID DYNAMICS; AERODYNAMIC CHARACTERISTICS
20090017814 NASA Johnson Space Center, Houston, TX, United States
Behavioral Health and Performance Element: Tools and Technologies
Leveton, Lauren B.; April 24, 2009; In English; Meeting of the American Occupational Therapy Foundation, 24 Apr. 2009, Houston, TX, United States; Original contains color and black and white illustrations
Report No.(s): JSC--CN-18235; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090017814
This slide presentation reviews the research into the Behavioral Health and Performance (BHP) of the Human Research Program. The program element goal is to identify, characterize and prevent or reduce behavioral health and performance risks associated with space travel, exploration, and return to terrestrial life. To accomplish this goal the program focuses on applied research that is designed to yield deliverables that reduce risk. There are several different elements that are of particular interest: Behavioral Medicine, Sleep, and team composition, and team work. In order to assure success for NASA missions the Human Research Program develops and validate the standards for each of the areas of interest. There is discussion of the impact on BHP while astronauts are on Long Duration Missions. The effort in this research is to create tools to meet the BHP concerns, these prospective tools are reviewed.
CASI
ASTRONAUTS; MENTAL HEALTH; ASTRONAUT PERFORMANCE; PSYCHOLOGICAL FACTORS; SPACE PSYCHOLOGY; SOCIAL FACTORS
20090017821 NASA Johnson Space Center, Houston, TX, United States
The Use of Pro/Engineer CAD Software and Fishbowl Tool Kit in Ray-tracing Analysis
Nounu, Hatem N.; Kim, Myung-Hee Y.; Ponomarev, Artem L.; Cucinotta, Francis A.; April 2009; In English; Original contains color illustrations
Report No.(s): JSC-CN-18247; Copyright; Avail.: CASI: A03, Hardcopy
This document is designed as a manual for a user who wants to operate the Pro/ENGINEER (ProE) Wildfire 3.0 with the NASA Space Radiation Program's (SRP) custom-designed Toolkit, called 'Fishbowl', for the ray tracing of complex spacecraft geometries given by a ProE CAD model. The analysis of spacecraft geometry through ray tracing is a vital part in the calculation of health risks from space radiation. Space radiation poses severe risks of cancer, degenerative diseases and acute radiation sickness during long-term exploration missions, and shielding optimization is an important component in the application of radiation risk models. Ray tracing is a technique in which 3-dimensional (3D) vehicle geometry can be represented as the input for the space radiation transport code and subsequent risk calculations. In ray tracing a certain number of rays (on the order of 1000) are used to calculate the equivalent thickness, say of aluminum, of the spacecraft geometry seen at a point of interest called the dose point. The rays originate at the dose point and terminate at a homogenously distributed set of points lying on a sphere that circumscribes the spacecraft and that has its center at the dose point. The distance a ray traverses in each material is converted to aluminum or other user-selected equivalent thickness. Then all equivalent thicknesses are summed up for each ray. Since each ray points to a direction, the aluminum equivalent of each ray represents the shielding that the geometry provides to the dose point from that particular direction. This manual will first list for the user the contact information for help in installing ProE and Fishbowl in addition to notes on the platform support and system requirements information. Second, the document will show the user how to use the software to ray trace a Pro/E-designed 3-D assembly and will serve later as a reference for troubleshooting. The user is assumed to have previous knowledge of ProE and CAD modeling.
Author
COMPUTER AIDED DESIGN; COMPUTER PROGRAMS; RAY TRACING; EXTRATERRESTRIAL RADIATION; RADIATION SHIELDING; SPACECRAFT SHIELDING; RADIATION TRANSPORT
20090017830 NASA Marshall Space Flight Center, Huntsville, AL, United States
Survey of International Space Station Charging Events
Craven, P. D.; Wright, Kenneth H., Jr.; Minow, Joseph I.; Coffey, Victoria N.; Schneider, Todd A.; Vaughn, Jason A.; Ferguson, Dale C.; Parker, Linda N.; January 05, 2009; In English; 47th AIAA Aerospace Sciences Meeting, 5-8 Jan. 2009, Orlando, FL, United States; Original contains color illustrations
Report No.(s): M09-0218; Copyright; Avail.: CASI: A03, Hardcopy
With the negative grounding of the 160V Photovoltaic (PV) arrays, the experience varied and interesting charging events. August 2006, there has been a multi-probe package, called the Floating Potential to provide redundant measurements of the floating of the ISS as well as the density and temperature of the local plasma environment. intermittent data campaigns since August 2006 and has charging of the ISS as it has progressed from one to three PV arrays and with various additional modules such as the laboratory and the Japan Aerospace Exploration Kibo laboratory. This paper summarizes the charging of the ISS and the local to those charging events, both as measured by the
Author
INTERNATIONAL SPACE STATION; SPACECRAFT CHARGING; PHOTOVOLTAIC CELLS
20090017831 NASA Goddard Space Flight Center, Greenbelt, MD, United States
Self-Consistent Model of Magnetospheric Electric Field, Ring Current, Plasmasphere, and Electromagnetic Ion Cyclotron Waves: Initial Results
Gamayunov, K. V.; Khazanov, G. V.; Liemohn, M. W.; Fok, M.-C.; Ridley, A. J.; [2009]; In English
Report No.(s): M09-0228; Copyright; Avail.: CASI: A05, Hardcopy
Avail Online: http://dx.doi.org/10.1029/2008JA013597
Further development of our self-consistent model of interacting ring current (RC) ions and electromagnetic ion cyclotron (EMIC) waves is presented. This model incorporates large scale magnetosphere-ionosphere coupling and treats self-consistently not only EMIC waves and RC ions, but also the magnetospheric electric field, RC, and plasmasphere. Initial simulations indicate that the region beyond geostationary orbit should be included in the simulation of the magnetosphere-ionosphere coupling. Additionally, a self-consistent description, based on first principles, of the ionospheric conductance is required. These initial simulations further show that in order to model the EMIC wave distribution and wave spectral properties accurately, the plasmasphere should also be simulated self-consistently, since its fine structure requires as much care as that of the RC. Finally, an effect of the finite time needed to reestablish a new potential pattern throughout the ionosphere and to communicate between the ionosphere and the equatorial magnetosphere cannot be ignored.
Author
ELECTRIC FIELDS; ELECTROMAGNETIC RADIATION; ION CYCLOTRON RADIATION; MAGNETOSPHERE-IONOSPHERE COUPLING; PLASMASPHERE; RING CURRENTS; ATMOSPHERIC MODELS; EARTH MAGNETOSPHERE
20090017832 Mississippi State Univ., Mississippi State, MS, United States
Dislocations: 75 years of Deformation Mechanisms
Schneider, Judy; Journal of Materials; [2009]; vol. Volume 51; issue No. 2; pp. 3; In English
Report No.(s): M09-0248; No Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090017832
The selection of papers presented in this section reflect on themes to be explored at the "Dislocations: 75 years of Deformation Mechanisms" Symposium to be held at the Annual 2009 TMS meeting. The symposium was sponsored by the Mechanical Behavior of Materials Committee to give tribute to the evolution of a concept that has formed the basis of our mechanistic understanding of how crystalline solids plastically deform and how they fail.
Derived from text
DEFORMATION; MECHANICAL PROPERTIES; DISLOCATIONS (MATERIALS)
20090017833 NASA Marshall Space Flight Center, Huntsville, AL, United States; Mississippi State Univ., MS, United States
Investigating the Effects of Pin Tool Design on Friction Stir Welded Ti-6Al-4V
Rubisoff, H. A.; Querin, J. A.; Schneider, Judy A.; Magee, D.; February 15, 2009; In English; The Minerals, Metals and Materials Society (TMS) Conference, 15-19 Feb. 2009, San Francisco, CA, United States; Original contains color and black and white illustrations
Report No.(s): M09-0309; Copyright; Avail.: CASI: A03, Hardcopy
Friction stir welding (FSWing), a solid state joining technique, uses a non-consumable rotating pin tool to thermomechanically join materials. Heating of the weldment caused by friction and deformation is a function of the interaction between the pin tool and the work piece. Therefore, the geometry of the pin tool is in part responsible for the resulting microstructure and mechanical properties. In this study microwave sintered tungsten carbide (WC) pin tools with tapers and flats were used to FSW Ti-6Al-4V. Transverse sections of welds were mechanically tested, and the microstructure was characterized using optical microscopy (OM) and scanning election microscopy (SEM). X-ray diffraction (XRD) and electron back-scatter diffraction (EBSD) were used to characterize the texture within the welds produced from the different pin tool designs.
Author
FRICTION STIR WELDING; TITANIUM ALLOYS; TUNGSTEN CARBIDES; WELDED JOINTS; ALUMINUM ALLOYS; PINS; ROTATION; X RAY DIFFRACTION
20090017834 NASA Marshall Space Flight Center, Huntsville, AL, United States
On Favorable Thermal Fields for Detached Bridgman Growth
Stelian, Carmen; Volz, Martin P.; Derby, Jeffrey J.; [2009]; In English; Original contains black and white illustrations
Contract(s)/Grant(s): DE-FG5206NA27498
Report No.(s): M09-0311; Copyright; Avail.: CASI: A03, Hardcopy
The thermal fields of two Bridgman-like configurations, representative of real systems used in prior experiments for the detached growth of CdTe and Ge crystals, are studied. These detailed heat transfer computations are performed using the CrysMAS code and expand upon our previous analyses [14] that posited a new mechanism involving the thermal field and meniscus position to explain stable conditions for dewetted Bridgman growth. Computational results indicate that heat transfer conditions that led to successful detached growth in both of these systems are in accordance with our prior assertion, namely that the prevention of crystal reattachment to the crucible wall requires the avoidance of any undercooling of the melt meniscus during the growth run. Significantly, relatively simple process modifications that promote favorable thermal conditions for detached growth may overcome detrimental factors associated with meniscus shape and crucible wetting. Thus, these ideas may be important to advance the practice of detached growth for many materials.
Author
BRIDGMAN METHOD; HEAT TRANSFER; SUPERCOOLING; PREVENTION; CRYSTALS
20090017836 NASA Marshall Space Flight Center, Huntsville, AL, United States
Results of the Fluid Merging Viscosity Measurement International Space Station Experiment
Ethridge, Edwin C.; Kaukler, William; Antar, Basil; January 05, 2009; In English; 47th AIAA Aerospace Sciences Meeting, 5-8 Jan. 2009, Orlando, FL, United States; Original contains color illustrations
Report No.(s): MSFC-2188; Copyright; Avail.: CASI: A01, Hardcopy
The purpose of FMVM is to measure the rate of coalescence of two highly viscous liquid drops and correlate the results with the liquid viscosity and surface tension. The experiment takes advantage of the low gravitational free floating conditions in space to permit the unconstrained coalescence of two nearly spherical drops. The merging of the drops is accomplished by deploying them from a syringe and suspending them on Nomex threads followed by the astronaut s manipulation of one of the drops toward a stationary droplet till contact is achieved. Coalescence and merging occurs due to shape relaxation and reduction of surface energy, being resisted by the viscous drag within the liquid. Experiments were conducted onboard the International Space Station in July of 2004 and subsequently in May of 2005. The coalescence was recorded on video and down-linked near real-time. When the coefficient of surface tension for the liquid is known, the increase in contact radius can be used to determine the coefficient of viscosity for that liquid. The viscosity is determined by fitting the experimental speed to theoretically calculated contact radius speed for the same experimental parameters. Recent fluid dynamical numerical simulations of the coalescence process will be presented. The results are important for a better understanding of the coalescence process. The experiment is also relevant to liquid phase sintering, free form in-situ fabrication, and as a potential new method for measuring the viscosity of viscous glass formers at low shear rates.
Author
COALESCING; DROPS (LIQUIDS); INTERFACIAL TENSION; LIQUID PHASE SINTERING; SURFACE ENERGY; VISCOSITY; LIQUID SURFACES; REAL TIME OPERATION
20090017841 NASA Glenn Research Center, Cleveland, OH, United States
Testing of a Microwave Blade Tip Clearance Sensor at the NASA Glenn Research Center
Woike, Mark R.; Roeder, James W.; Hughes, Christopher E.; Bencic, Timothy J.; April 2009; In English; 47th Aerospace Sciences meeting, 5-8 Jan. 2009, Orlando, FL, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 984754.02.07.03.13.06
Report No.(s): NASA/TM-2009-215589; AIAA Paper-2009-1452; E-16826-1; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090017841
The development of new active tip clearance control and structural health monitoring schemes in turbine engines and other types of rotating machinery requires sensors that are highly accurate and can operate in a high-temperature environment. The use of a microwave sensor to acquire blade tip clearance and tip timing measurements is being explored at the NASA Glenn Research Center. The microwave blade tip clearance sensor works on principles that are very similar to a short-range radar system. The sensor sends a continuous microwave signal towards a target and measures the reflected signal. The phase difference of the reflected signal is directly proportional to the distance between the sensor and the target being measured. This type of sensor is beneficial in that it has the ability to operate at extremely high temperatures and is unaffected by contaminants that may be present in turbine engines. The use of microwave sensors for this application is a new concept. Techniques on calibrating the sensors along with installation effects are not well quantified as they are for other sensor technologies. Developing calibration techniques and evaluating installation effects are essential in using these sensors to make tip clearance and tip timing measurements. As a means of better understanding these issues, the microwave sensors were used on a benchtop calibration rig, a large axial vane fan, and a turbofan. Background on the microwave tip clearance sensor, an overview of their calibration, and the results from their use on the axial vane fan and the turbofan will be presented in this paper.
Author
BLADE TIPS; CLEARANCES; MICROWAVE SENSORS; STRUCTURAL HEALTH MONITORING; TURBOFAN ENGINES
20090017842 NASA Glenn Research Center, Cleveland, OH, United States
A Review of State-of-the-Art Separator Materials for Advanced Lithium-Based Batteries for Future Aerospace Missions
Bladwin, Richard S.; March 2009; In English; Original contains black and white illustrations
Contract(s)/Grant(s): WBS 038957.04.07.02.01.03
Report No.(s): NASA/TM-2009-215590; E-16879; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090017842
As NASA embarks on a renewed human presence in space, safe, human-rated, electrical energy storage and power generation technologies, which will be capable of demonstrating reliable performance in a variety of unique mission environments, will be required. To address the future performance and safety requirements for the energy storage technologies that will enhance and enable future NASA Constellation Program elements and other future aerospace missions, advanced rechargeable, lithium-ion battery technology development is being pursued with an emphasis on addressing performance technology gaps between state-of-the-art capabilities and critical future mission requirements. The material attributes and related performance of a lithium-ion cell's internal separator component are critical for achieving overall optimal performance, safety and reliability. This review provides an overview of the general types, material properties and the performance and safety characteristics of current separator materials employed in lithium-ion batteries, such as those materials that are being assessed and developed for future aerospace missions.
Author
LITHIUM BATTERIES; METAL IONS; SPACE MISSIONS; SEPARATORS; AEROSPACE SCIENCES; MISSION PLANNING
20090017843 NASA Glenn Research Center, Cleveland, OH, United States
Nearly Interactive Parabolized Navier-Stokes Solver for High Speed Forebody and Inlet Flows
Benson, Thomas J.; Liou, May-Fun; Jones, William H.; Trefny, Charles J.; April 2009; In English; 47th Aerospace Sciences Meeting, 5-8 Jan. 2009, Orlando, FL, United States; Original contains color illustrations
Contract(s)/Grant(s): WBS 599489.02.07.03.07.02.04
Report No.(s): NASA/TM-2009-215598; AIAA-2009-0711; E-16889; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090017843
A system of computer programs is being developed for the preliminary design of high speed inlets and forebodies. The system comprises four functions: geometry definition, flow grid generation, flow solver, and graphics post-processor. The system runs on a dedicated personal computer using the Windows operating system and is controlled by graphical user interfaces written in MATLAB (The Mathworks, Inc.). The flow solver uses the Parabolized Navier-Stokes equations to compute millions of mesh points in several minutes. Sample two-dimensional and three-dimensional calculations are demonstrated in the paper.
Author
FOREBODIES; HIGH SPEED; INLET FLOW; NAVIER-STOKES EQUATION; COMPUTATIONAL FLUID DYNAMICS; ENGINE INLETS
20090017844 NASA Glenn Research Center, Cleveland, OH, United States
Orion Service Module Reaction Control System Plume Impingement Analysis Using PLIMP/RAMP2
Wang, Xiao-Yen; Lumpkin, Forrest E., III; Gati, Frank; Yuko, James R.; Motil, Brian J.; March 2009; In English; 47th AIAA Aerospace Sciences Meeting and Exhibit, 5-8 Jan. 2009, Orlando, FL, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 736466.11.01.03.01.02
Report No.(s): NASA/TM-2009-215601; AIAA-2009-0834; E-16823-1; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090017844
The Orion Crew Exploration Vehicle Service Module Reaction Control System engine plume impingement was computed using the plume impingement program (PLIMP). PLIMP uses the plume solution from RAMP2, which is the refined version of the reacting and multiphase program (RAMP) code. The heating rate and pressure (force and moment) on surfaces or components of the Service Module were computed. The RAMP2 solution of the flow field inside the engine and the plume was compared with those computed using GASP, a computational fluid dynamics code, showing reasonable agreement. The computed heating rate and pressure using PLIMP were compared with the Reaction Control System plume model (RPM) solution and the plume impingement dynamics (PIDYN) solution. RPM uses the GASP-based plume solution, whereas PIDYN uses the SCARF plume solution. Three sets of the heating rate and pressure solutions agree well. Further thermal analysis on the avionic ring of the Service Module was performed using MSC Patran/Pthermal. The obtained temperature results showed that thermal protection is necessary because of significant heating from the plume.
Author
AVIONICS; COMPUTATIONAL FLUID DYNAMICS; IMPINGEMENT; PLUMES; REACTION CONTROL; SERVICE MODULE (ISS); CREW EXPLORATION VEHICLE
20090017845 NASA Langley Research Center, Hampton, VA, United States
Perspectives on Highly Adaptive or Morphing Aircraft
McGowan, Anna-Maria R.; Vicroy, Dan D.; Busan, Ronald C.; Hahn, Andrew S.; April 20, 2009; In English; NATO RTO AVT-168 Symposium, 20-24 Apr. 2009, Lisbon, Portugal; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 7812350715
Report No.(s): LF99-8639; RTO-MP-AVT-168; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090017845
The ability to adapt to different flight conditions has been fundamental to aircraft design since the Wright Brothers first flight. Over a hundred years later, unconventional aircraft adaptability, often called aircraft morphing has become a topic of considerable renewed interest. In the past two decades, this interest has been largely fuelled by advancements in multi-functional or smart materials and structures. However, highly adaptive or morphing aircraft is certainly a cross-discipline challenge that stimulates a wide range of design possibilities. This paper will review some of the history of morphing aircraft including recent research programs and discuss some perspectives on this work.
Author
AERONAUTICAL ENGINEERING; AIRCRAFT DESIGN; SWEPT WINGS; ADAPTIVE CONTROL; AIRCRAFT CONFIGURATIONS
20090017846 NASA Langley Research Center, Hampton, VA, United States
Lessons Learned from Numerical Simulations of the F-16XL Aircraft at Flight Conditions
Rizzi, Arthur; Jirasek, Adam; Lamar, John; Crippa, Simone; Badcock, Kenneth; Boelens, Oklo; Journal of Aircraft 2009; 2009; ISSN 0021-8669; vol. Volume 46; issue No. 2; pp. 423-44; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 526282.01.07.04.01.
Report No.(s): LF99-7384; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://dx.doi.org/10.2514/1.35698
Nine groups participating in the Cranked Arrow Wing Aerodynamics Project International (CAWAPI) project have contributed steady and unsteady viscous simulations of a full-scale, semi-span model of the F-16XL aircraft. Three different categories of flight Reynolds/Mach number combinations were computed and compared with flight-test measurements for the purpose of code validation and improved understanding of the flight physics. Steady-state simulations are done with several turbulence models of different complexity with no topology information required and which overcome Boussinesq-assumption problems in vortical flows. Detached-eddy simulation (DES) and its successor delayed detached-eddy simulation (DDES) have been used to compute the time accurate flow development. Common structured and unstructured grids as well as individually-adapted unstructured grids were used. Although discrepancies are observed in the comparisons, overall reasonable agreement is demonstrated for surface pressure distribution, local skin friction and boundary velocity profiles at subsonic speeds. The physical modeling, steady or unsteady, and the grid resolution both contribute to the discrepancies observed in the comparisons with flight data, but at this time it cannot be determined how much each part contributes to the whole. Overall it can be said that the technology readiness of CFD-simulation technology for the study of vehicle performance has matured since 2001 such that it can be used today with a reasonable level of confidence for complex configurations.
Author (revised)
COMPUTATIONAL FLUID DYNAMICS; DIRECT NUMERICAL SIMULATION; F-16 AIRCRAFT; FLIGHT TESTS; FLIGHT CONDITIONS; LESSONS LEARNED; AERODYNAMICS
Additions to the NASA Aeronautics and Space Database as of 05/22/2009
20090017880 Alabama Univ., Huntsville, AL, United States
Magnetohydrodynamic Effects in Propagating Relativistic Ejecta: Reverse Shock and Magnetic Acceleration
Mizuno, Y.; Nishikawa, K.I.; Zhang, B.; Giacomazzo, B.; Hardee, P.E.; Nagataki, S.; Hartmann, D.H.; October 20, 2008; In English; Sixth Huntsville Gamma-Ray Burst Symposium, 20 - 23 Oct. 2008, Alabama, United States; Original contains black and white illustrations
Contract(s)/Grant(s): NNX08AE57ANNG05GB67G; NNG05GB68G; AST-0506719; AST-0506666; NNG05GK73G; NNX07AJ88G
Report No.(s): M09-0295; Copyright; Avail.: CASI: A01, Hardcopy
We solve the Riemann problem for the deceleration of arbitrarily magnetized relativistic ejecta injected into a static unmagnetized medium. We find that for the same initial Lorentz factor, the reverse shock becomes progressively weaker with increasing magnetization s (the Poynting-to-kinetic energy flux ratio), and the shock becomes a rarefaction wave when s exceeds a critical value, sc, defined by the balance between the magnetic pressure in the ejecta and the thermal pressure in the forward shock. In the rarefaction wave regime, we find that the rarefied region is accelerated to a Lorentz factor that is significantly larger than the initial value. This acceleration mechanism is due to the strong magnetic pressure in the ejecta.
Author
GAMMA RAY BURSTS; EJECTA; DECELERATION; MAGNETOHYDRODYNAMICS; SHOCK WAVES; CAUCHY PROBLEM
20090017881 NASA Marshall Space Flight Center, Huntsville, AL, United States; Mississippi State Univ., Mississippi State, MS, United States
Control of Structure in Conventional Friction Stir Welds through a Kinematic Theory of Metal Flow
Rubisoff, H.A.; Schneider, J.A.; Nunes, A.C.; February 15, 2009; In English; Minerals, Metals, and Materials Society (TMS) Conference, 15 - 19 Feb. 2009, San Francisco, CA, United States; Original contains color and black and white illustrations
Report No.(s): M09-0308; Copyright; Avail.: CASI: A03, Hardcopy
In friction stir welding (FSW), a rotating pin is translated along a weld seam so as to stir the sides of the seam together. Metal is prevented from flowing up the pin, which would result in plowing/cutting instead of welding, by a shoulder on the pin. In conventional FSW, the weld metal rests on an "anvil", which supports the heavy "plunge" load on the tool. In this study, both embedded tungsten wires along and copper plating on the faying surfaces were used to trace the flow of AA2219 weld metal around the C-FSW tool. The effect of tool rotational speed, travel speed, plunge load, and pin thread pitch on the resulting weld metal flow was evaluated. Plan, longitudinal, and transverse section x-ray radiographs were examined to trace the metal flow paths. The results are interpreted in terms of a kinematic theory of metal flow in FSW.
Author
FRICTION STIR WELDING; WELDED JOINTS; RADIOGRAPHY; SEAMS (JOINTS); ROTATION; LOADS (FORCES); KINEMATICS; CONTROL SYSTEMS DESIGN
20090017882 NASA Marshall Space Flight Center, Huntsville, AL, United States
Oxygen Production from Lunar Regolith using Ionic Liquids
Paley, Mark Steven; Karr, Laurel J.; Curreri, Peter; February 24, 2009; In English; Space, Propulsion and Energy Sciences International Forum, 24-26 Feb. 2009, Huntsville, AL, United States; Original contains color illustrations
Report No.(s): M09-0326; MSFC-2200; Copyright; Avail.: CASI: A03, Hardcopy
The objective of this work and future follow-on work is to develop a safe, efficient, and recyclable method for oxygen and/or metals extraction from lunar regolith, in support of establishing a manned lunar outpost. The approach is to solubilize the oxides that comprise lunar regolith in media consisting of ionic liquids (ILs) and/or their mixtures at temperatures at or below 300 C. Once in solution, electrolysis can either be performed in-situ to generate oxygen at the anode and hydrogen and/or metals (silicon, iron, aluminum, titanium, etc.) at the cathode. Alternatively, the water that is generated during the solubilization process can be distilled out and condensed into a separate IL and then electrolysized to produce hydrogen and oxygen. In the case of lunar regolith, this method could theoretically produce 44g oxygen per 100g of regolith. The oxygen can be used for human life support and/or as an oxidizer for rocket fuels, and the metals can be used as raw materials for construction and/or device fabrication. Moreover, the hydrogen produced can be used to re-generate the acidic medium, which can then be used to process additional regolith, thereby making the materials recyclable and limiting upmass requirements. An important advantage of IL acid systems is that they are much "greener" and safer than conventional materials used for regolith processing such as sulfuric or hydrochloric acids. They have very low vapor pressures, which means that they contain virtually no toxic and/or flammable volatile content, they are relatively non-corrosive, and they can exhibit good stability in harsh environments (extreme temperatures, hard vacuum, etc.). Furthermore, regolith processing can be achieved at lower temperatures than other processes such as molten oxide electrolysis or hydrogen reduction, thereby reducing initial power requirements. Six ILs have been synthesized and tested for their capability to dissolve lunar simulant, and for electrochemical and thermal stability. The results showed that ILs can be very efficient electrolytes; in particular IL/phosphoric-acid mixtures appear extremely promising for solubilizing lunar simulant. Results from preliminary experiments for distillation of water produced from the oxygen within the metal oxides of the simulant and the hydrogen from the acid indicates that over 75% of the oxygen from the simulant can be harvested as water at a temperature of 150 C. A method for collection of oxygen from electrolysis of the water derived from solubilizing simulant was developed by using a liquid nitrogen trap to liquefy and collect the oxygen. Although precise quantification of the liquid oxygen trapped is difficult to obtain, the amount of hydrogen and oxygen collected from electrolysis of water in this system was greater than 98%. This set-up also included a portable mass spectrometer for the identification of gases released from electrolysis cells. Regeneration of ILs through re-protonation was also demonstrated. Four sequential re-generations of an IL following solubilization of simulant showed no significant differences in amounts of simulant dissolved. Follow-on work for this project should include more studies of IL/phosphoric acid systems. Also, much more work is necessary for defining methods for electrolysis and purification of metals from regolith solubilized in ILs, and for developing a system to use the produced hydrogen to regenerate the spent IL. Finally, design and development of flight breadboard and prototype hardware is required.
Author
ELECTROLYSIS; LIFE SUPPORT SYSTEMS; LUNAR ROCKS; METALS; OXYGEN; OXYGEN PRODUCTION; IONS; LIQUIDS
20090017883 NASA Marshall Space Flight Center, Huntsville, AL, United States
Space Flight Plasma Data Analysis
Wright, Kenneth H.; Minow, Joseph I.; February 27, 2009; In English; Original contains color and black and white illustrations
Report No.(s): M09-0335; Copyright; Avail.: CASI: A03, Hardcopy
This slide presentation reviews a method to analyze the plasma data that is reported on board the International Space station (ISS). The Floating Potential Measurement Unit (FPMU), the role of which is to obtain floating potential and ionosphere plasma measurements for validation of the ISS charging model, assess photo voltaic array variability and interpreting IRI predictions, is composed of four probes: Floating Potential Probe (FPP), Wide-sweep Langmuir Probe (WLP), Narrow-sweep Langmuir Probe (NLP) and the Plasma Impedance Probe (PIP). This gives redundant measurements of each parameter. There are also many 'boxes' that the data must pass through before being captured by the ground station, which leads to telemetry noise. Methods of analysis for the various signals from the different sets are reviewed. There is also a brief discussion of LP analysis of Low Earth Orbit plasma simulation source.
CASI
ELECTROSTATIC PROBES; IMPEDANCE PROBES; PLASMA PROBES; DATA REDUCTION; SIGNAL ANALYSIS; PLASMAS (PHYSICS); SPACECRAFT CHARGING
20090017885 NASA Marshall Space Flight Center, Huntsville, AL, United States
Validation of Ionospheric Measurements from the International Space Station (ISS)
Coffey, Victoria; Minow, Joseph; Wright, Kenneth; February 11, 2009; In English; Directions in Ionosphere-Thermosphere-Mesosphere Research: A Vision for Aeronomy in the Earth-Sun System, 10-12 Feb. 2009, Redondo Beach, CA, United States; Original contains color and black and white illustrations
Report No.(s): M09-0346; Copyright; Avail.: CASI: A01, Hardcopy
The International Space Station orbit provides an ideal platform for in-situ studies of space weather effects on the mid and low-latitude F-2 region ionosphere. The Floating Potential Measurement Unit (FPMU) operating on the ISS since Aug 2006, is a suite of plasma instruments: a Floating Potential Probe (FPP), a Plasma Impedance Probe (PIP), a Wide-sweep Langmuir Probe (WLP), and a Narrow-Sweep Langmuir Probe. This instrument package provides a new opportunity for collaborative multi-instrument studies of the F-region ionosphere during both quiet and disturbed periods. This presentation first describes the operational parameters for each of the FPMU probes and shows examples of an intra-instrument validation. We then show comparisons with the plasma density and temperature measurements derived from the TIMED GUVI ultraviolet imager, the Millstone Hill ground based incoherent scatter radar, and DIAS digisondes, Finally we show one of several observations of night-time equatorial density holes demonstrating the capabilities of the probes for monitoring mid and low latitude plasma processes.
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PLASMA DENSITY; SPACE WEATHER; EARTH IONOSPHERE; EVALUATION; PROVING; SPACE PLASMAS
20090017886 NASA Marshall Space Flight Center, Huntsville, AL, United States
Environmental Factors Affecting Asthma and Allergies: Predicting and Simulating Downwind Exposure to Airborne Pollen
Luvall, Jeffrey; Estes, Sue; Sprigg, William A.; Nickovic, Slobodan; Huete, Alfredo; Solano, Ramon; Ratana, Piyachat; Jiang, Zhangyan; Flowers, Len; Zelicoff, Alan; February 24, 2009; In English; Track2009: The Future of Environmental Public Health, 24-26 Feb. 2009, Washington, DC, United States; Original contains color and black and white illustrations
Report No.(s): M09-0354; Copyright; Avail.: CASI: A03, Hardcopy
This slide presentation reviews the environmental factors that affect asthma and allergies and work to predict and simulate the downwind exposure to airborne pollen. Using a modification of Dust REgional Atmosphere Model (DREAM) that incorporates phenology (i.e. PREAM) the aim was to predict concentrations of pollen in time and space. The strategy for using the model to simulate downwind pollen dispersal, and evaluate the results. Using MODerate-resolution Imaging Spectroradiometer (MODIS), to get seasonal sampling of Juniper, the pollen chosen for the study, land cover on a near daily basis. The results of the model are reviewed.
CASI
ALLERGIC DISEASES; ATMOSPHERIC MODELS; PHENOLOGY; PREDICTIONS; SIMULATION; WIND DIRECTION; POLLEN
20090017891 NASA Marshall Space Flight Center, Huntsville, AL, United States
Objectives and Progress on Integrated Vehicle Ground Vibration Testing for the Ares Launch Vehicles
Tuma, Margaret L.; Asloms. Brice R.; January 05, 2009; In English; AIAA 2009 Aerospace Sciences Meeting, 5-8 Jan. 2009, Orlando, FL, United States; Original contains color and black and white illustrations
Report No.(s): MSFC-2196; No Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090017891
As NASA begins design and development of the Ares launch vehicles to replace the Space Shuttle and explore beyond low Earth orbit, Integrated Vehicle Ground Vibration Testing (IVGVT) will be a vital component of ensuring that those vehicles can perform the missions assigned to them. A ground vibration test (GVT) is intended to measure by test the fundamental dynamic characteristics of launch vehicles during various phases of flight. During the series of tests, properties such as natural frequencies, mode shapes, and transfer functions are measured directly. This data is then used to calibrate loads and control systems analysis models for verifying analyses of the launch vehicle. The Ares Flight & Integrated Test Office (FITO) will be conducting IVGVT for the Ares I crew launch vehicle at Marshall Space Flight Center (MSFC) from 2011 to 2012 using the venerable Test Stand (TS) 4550, which supported similar tests for the Saturn V and Space Shuttle vehicle stacks.
Author
SATURN 5 LAUNCH VEHICLES; ARES 1 LAUNCH VEHICLE; LOADS (FORCES); GROUND TESTS; DYNAMIC CHARACTERISTICS; VIBRATION TESTS; TEST STANDS
20090017895 NASA Marshall Space Flight Center, Huntsville, AL, United States
Extraction of Water from Polar Lunar Permafrost with Microwaves - Dielectric Property Measurements
Ethridge, Edwin C.; Kaukler, William; January 05, 2009; In English; 47th AIAA Aerospace Sciences Meeting, 5-8 Jan. 2009, Orlando, FL, United States; Original contains color and black and white illustrations
Report No.(s): MSFC-2202; Copyright; Avail.: CASI: A03, Hardcopy
Remote sensing indicates the presence of hydrogen rich regions associated with the lunar poles. The logical hypothesis is that there is cryogenically trapped water ice located in craters at the lunar poles. Some of the craters have been in permanent darkness for a billion years. The presence of water at the poles as well as other scientific advantages of a polar base, have influenced NASA plans for the lunar outpost. The lunar outpost has water and oxygen requirements on the order of 1 ton per year scaling up to as much as 10 tons per year. Microwave heating of the frozen permafrost has unique advantages for water extraction. Proof of principle experiments have successfully demonstrated that microwaves will couple to the cryogenic soil in a vacuum and the sublimed water vapor can be successfully captured on a cold trap. The dielectric properties of lunar soil will determine the hardware requirements for extraction processes. Microwave frequency dielectric property measurements of lunar soil simulant have been measured.
Author
EXTRACTION; ICE; MICROWAVES; PERMAFROST; WATER; MOON; IN SITU RESOURCE UTILIZATION; POLAR REGIONS
20090017898 Ohio State Univ., Columbus, OH, United States
Ceramics for Molten Materials Transfer
Standish, Evan; Stefanescu, Doru M.; Curreri, Peter A.; January 05, 2009; In English; 47th AIAA Aerospace Sciences Meeting, 5-8 Jan. 2009, Orlando, FL, United States; Original contains black and white illustrations
Report No.(s): MSFC-2204; Copyright; Avail.: CASI: A03, Hardcopy
The paper reviews the main issues associated with molten materials transfer and the operation of a high temperature used to produce oxygen, with molten iron and silicon as purposely designed technologies show exploitation. extensive investigation is the performance of currently used for the purpose of molten metal containment and transfer electrolytic cells. unit at a scale equivalent to the production of 1 ton of oxygen per year are introduced. This implies a mass of molten equivalent of 1kg regolithlhr
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LUNAR SURFACE; ELECTROWINNING; ELECTROLYTIC CELLS; OXYGEN PRODUCTION; REGOLITH; LUNAR ROCKS; IN SITU RESOURCE UTILIZATION
20090017899 NASA Marshall Space Flight Center, Huntsville, AL, United States
Ceramics for Molten Materials Containment, Transfer and Handling on the Lunar Surface
Standish, Evan; Stefanescu, Doru M.; Curreri, Peter A.; January 05, 2009; In English; 47th AIAA Aerospace Sciences Meeting, 5-8 Jan. 2009, Orlando, FL, United States; Original contains black and white illustrations
Report No.(s): MSFC-2207; Copyright; Avail.: CASI: A03, Hardcopy
As part of a project on Molten Materials Transfer and Handling on the Lunar Surface, molten materials containment samples of various ceramics were tested to determine their performance in contact with a melt of lunar regolith simulant. The test temperature was 1600 C with contact times ranging from 0 to 12 hours. Regolith simulant was pressed into cylinders with the approximate dimensions of 1.25 dia x 1.25cm height and then melted on ceramic substrates. The regolith-ceramic interface was examined after processing to determine the melt/ceramic interaction. It was found that the molten regolith wetted all oxide ceramics tested extremely well which resulted in chemical reaction between the materials in each case. Alumina substrates were identified which withstood contact at the operating temperature of a molten regolith electrolysis cell (1600 C) for eight hours with little interaction or deformation. This represents an improvement over alumina grades currently in use and will provide a lifetime adequate for electrolysis experiments lasting 24 hours or more. Two types of non-oxide ceramics were also tested. It was found that they interacted to a limited degree with the melt resulting in little corrosion. These ceramics, Sic and BN, were not wetted as well as the oxides by the melt, and so remain possible materials for molten regolith handling. Tests wing longer holding periods and larger volumes of regolith are necessary to determine the ultimate performance of the tested ceramics.
Author
CHEMICAL REACTIONS; CERAMICS; SURFACE PROPERTIES; LUNAR SURFACE; REGOLITH; MATERIALS HANDLING; CONTAINMENT; ELECTROLYSIS
20090017903 NASA Langley Research Center, Hampton, VA, United States
Wind Characterization for the Assessment of Collision Risk During Flight Level Changes
Carreno, Victor; Chartrand, Ryan; April 2009; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 411931.02.51.07.01
Report No.(s): NASA/TM-2009-215717; L-19467; LF99-6686; Copyright; Avail.: CASI: A03, Hardcopy
A model of vertical wind gradient is presented based on National Oceanic and Atmospheric Administration (NOAA) wind data. The objective is to have an accurate representation of wind to be used in Collision Risk Models (CRM) of aircraft procedures. Depending on how an aircraft procedure is defined, wind and the different characteristics of the wind will have a more severe or less severe impact on distances between aircraft. For the In-Trail Procedure, the non-linearity of the vertical wind gradient has the greatest impact on longitudinal distance. The analysis in this paper extracts standard deviation, mean, maximum, and linearity characteristics from the NOAA data.
Author
WIND MEASUREMENT; ATMOSPHERIC CIRCULATION; AIRCRAFT MODELS; COLLISIONS; WIND (METEOROLOGY); STANDARD DEVIATION
20090017905 NASA Langley Research Center, Hampton, VA, United States
Synthetic and Enhanced Vision System for Altair Lunar Lander
Prinzell, Lawrence J., III; Kramer, Lynda J.; Norman, Robert M.; Arthur, Jarvis J., III; Williams, Steven P.; Shelton, Kevin J.; Bailey, Randall E.; April 27, 2009; In English; 15th International Symposium on Aviation Psychology, 27-30 Apr. 2009, Dayton, OH, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 609866.02.07.07.02
Report No.(s): LF99-8443; Copyright; Avail.: CASI: A02, Hardcopy
Past research has demonstrated the substantial potential of synthetic and enhanced vision (SV, EV) for aviation (e.g., Prinzel & Wickens, 2009). These augmented visual-based technologies have been shown to significantly enhance situation awareness, reduce workload, enhance aviation safety (e.g., reduced propensity for controlled flight -into-terrain accidents/incidents), and promote flight path control precision. The issues that drove the design and development of synthetic and enhanced vision have commonalities to other application domains; most notably, during entry, descent, and landing on the moon and other planetary surfaces. NASA has extended SV/EV technology for use in planetary exploration vehicles, such as the Altair Lunar Lander. This paper describes an Altair Lunar Lander SV/EV concept and associated research demonstrating the safety benefits of these technologies.
Author
ENHANCED VISION; ALTAIR LUNAR LANDER; FLIGHT CONTROL; FLIGHT SAFETY; AIRCRAFT SAFETY; SITUATIONAL AWARENESS
Additions to the NASA Aeronautics and Space Database as of 05/25/2009
20090017985 NASA Glenn Research Center, Cleveland, OH, United States
Synthetic and Biomass Alternate Fueling in Aviation
Hendricks, R. C.; Bushnell, D. M.; [2009]; In English
Contract(s)/Grant(s): WBS 561581.02.08.03.16.03
Report No.(s): E-16865; No Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090017985
While transportation fueling can accommodate a broad range of alternate fuels, aviation fueling needs are specific, such as the fuel not freezing at altitude or become too viscous to flow properly or of low bulk energy density that shortens range. The fuel must also be compatible with legacy aircraft, some of which are more than 50 years old. Worldwide, the aviation industry alone uses some 85-95 billion gallons of hydrocarbon-based fossil fuel each year, which is about 10% of the transportation industry. US civil aviation alone consumes nearly 14 billion gallons. The enormity of the problem becomes overwhelming, and the aviation industry is taking alternate fueling issues very seriously. Biofuels (algae, cyanobacteria, halophytes, weeds that use wastelands, wastewater and seatwater), when properly sourced, have the capacity to be drop-in fuel replacements for petroleum fuels. As such, biojet from such sources solves the aviation CO2 emissions issue without the downsides of 'conventional' biofuels, such as competing with food and fresh water resources. Of the many current fundamental problems, the major biofuel problem is cost. Both research and development and creative engineering are required to reduce these biofuels costs. Research is also ongoing in several 'improvement' areas including refining/processing and biologics with greater disease resistance, greater bio-oil productivity, reduced water/nutrient requirements, etc. The authors' current research is aimed at aiding industry efforts in several areas. They are considering different modeling approaches, growth media and refining approaches, different biologic feedstocks, methods of sequestering carbon in the processes, fuel certification for aviation use and, overall, ensuring that biofuels are feasible from all aspects - operability, capacity, carbon cycle and financial. The authors are also providing common discussion grounds/opportunities for the various parties, disciplines and concerned organization to share both issues and potential ways for moving forward, and overall, trying to educate those concerned about the innate limitations of 'conventional' biofuels and the solutions provided by non-traditional feedstocks that used waste lands/water or saline/salt water have an immense capacity potential.
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AIRCRAFT FUELS; SYNTHETIC FUELS; BIOCONVERSION; BIOMASS ENERGY PRODUCTION; ENERGY TECHNOLOGY; TECHNOLOGY ASSESSMENT; RESEARCH AND DEVELOPMENT; AIRCRAFT INDUSTRY
20090017987 NASA Langley Research Center, Hampton, VA, United States
Planar Fluorescence Imaging and Three-Dimensional Reconstructions of Capsule RCS Jets
Inman, Jennifer A.; Danehy, Paul M.; Alderfer, David W.; Buck, Gregory M.; Mccrea, Andrew C.; AIAA Journal; [2009]; vol. Volume 47; issue No. 7; pp. 803-81; In English; Original contains color illustrations
Report No.(s): LF99-7760; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://dx.doi.org/10.2514/1.37116
Planar laser-induced fluorescence (PLIF) flowfield visualization has been used to investigate reaction control system (RCS) jet flows in the wake of hypersonic capsule reentry vehicles. Pitch, roll, and yaw RCS jets were all studied. PLIF was used to obtain off-body flow images at planar slices in these flowfields, which are not easily visualized by other techniques owing to characteristically low gas density. When viewed individually, these slices are shown to provide spatially and temporally resolved information, including the locations and characteristics of turbulent flow structures and the location of the jet flow relative to the vehicle. In addition, ensembles of slices, acquired at multiple locations throughout the flowfield, are combined using computer visualization techniques to reconstruct the three-dimensional shape of the flow. Collectively, the off-body flow visualization data set acquired in these tests represents a valuable compliment to surface measurements, especially as a basis for explaining otherwise perplexing discrepancies between such measurements and computational fluid dynamics (CFD) results. The tests described herein were conducted in the 31-Inch Mach 10 Air Tunnel at NASA Langley Research Center.
Author
LASER INDUCED FLUORESCENCE; IMAGING TECHNIQUES; REACTION CONTROL; JET FLOW; HYPERSONIC REENTRY; FLOW VISUALIZATION; COMPUTATIONAL FLUID DYNAMICS
20090017989 Virginia Univ., VA, United States; NASA Langley Research Center, Hampton, VA, United States
Ares I Static Tests Design
Carson, William; Lindemuth, Kathleen; Mich, John; White, K. Preston; Parker, Peter A.; April 24, 2009; In English; Systems and Information Engineering Design Symposium, 24 Apr. 2009, Virginia, United States; Original contains black and white illustrations
Contract(s)/Grant(s): NNL08AA00B
Report No.(s): LF99-8552; Copyright; Avail.: CASI: A02, Hardcopy
Probabilistic engineering design enhances safety and reduces costs by incorporating risk assessment directly into the design process. In this paper, we assess the format of the quantitative metrics for the vehicle which will replace the Space Shuttle, the Ares I rocket. Specifically, we address the metrics for in-flight measurement error in the vector position of the motor nozzle, dictated by limits on guidance, navigation, and control systems. Analyses include the propagation of error from measured to derived parameters, the time-series of dwell points for the duty cycle during static tests, and commanded versus achieved yaw angle during tests. Based on these analyses, we recommend a probabilistic template for specifying the maximum error in angular displacement and radial offset for the nozzle-position vector. Criteria for evaluating individual tests and risky decisions also are developed.
Author
GUIDANCE (MOTION); SPACE SHUTTLES; STATIC TESTS; RISK ASSESSMENT; IN-FLIGHT MONITORING; NAVIGATION
20090018020 NASA Marshall Space Flight Center, Huntsville, AL, United States
IT Project Success w\7120 and 7123 NPRs to Achieve Project Success
Walley, Tina L.; February 24, 2009; In English; Sixth Annual NASA Project Management Challenge: Project Management Challenge 2009, 24 - 25 Feb. 2009, Florida, United States; Original contains color and black and white illustrations
Report No.(s): M09-0238; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090018020
This slide presentation reviews management techniques to assure information technology development project success. Details include the work products, the work breakdown structure (WBS), system integration, verification and validation (IV&V), and deployment and operations. An example, the NASA Consolidated Active Directory (NCAD), is reviewed.
CASI
INFORMATION SYSTEMS; MANAGEMENT METHODS; SYSTEMS MANAGEMENT; SYSTEMS ENGINEERING
Additions to the NASA Aeronautics and Space Database as of 05/26/2009
20090017534 Mikro Systems, Inc., Charlottesville, VA, United States
Fabricating High-Resolution X-Ray Collimators
Appleby, Michael; Atkinson, James E.; Fraser, Iain; Klinger, Jill; NASA Tech Briefs, May 2008; May 2008; pp. 1; In English
Report No.(s): GSC-15275-1; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.defensetechbriefs.com/component/content/article/2790-gsc-15275-1
A process and method for fabricating multi-grid, high-resolution rotating modulation collimators for arcsecond and sub-arcsecond x-ray and gamma-ray imaging involves photochemical machining and precision stack lamination. The special fixturing and etching techniques that have been developed are used for the fabrication of multiple high-resolution grids on a single array substrate. This technology has application in solar and astrophysics and in a number of medical imaging applications including mammography, computed tomography (CT), single photon emission computed tomography (SPECT), and gamma cameras used in nuclear medicine. This collimator improvement can also be used in non-destructive testing, hydrodynamic weapons testing, and microbeam radiation therapy.
Author
FABRICATION; COLLIMATORS; X RAY IMAGERY; HIGH RESOLUTION; PHOTOCHEMICAL REACTIONS; NONDESTRUCTIVE TESTS; MICROBEAMS; LAMINATES; ETCHING
20090017535 NASA Glenn Research Center, Cleveland, OH, United States
Symmetric Phase-Only Filtering in Particle-Image Velocimetry
Wemet, Mark P.; NASA Tech Briefs, May 2008; May 2008; pp. 33-3; In English
Report No.(s): LEW-17810-1; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2806
Symmetrical phase-only filtering (SPOF) can be exploited to obtain substantial improvements in the results of data processing in particle-image velocimetry (PIV). In comparison with traditional PIV data processing, SPOF PIV data processing yields narrower and larger amplitude correlation peaks, thereby providing more-accurate velocity estimates. The higher signal-to-noise ratios associated with the higher amplitude correlation peaks afford greater robustness and reliability of processing. SPOF also affords superior performance in the presence of surface flare light and/or background light. SPOF algorithms can readily be incorporated into pre-existing algorithms used to process digitized image data in PIV, without significantly increasing processing times. A summary of PIV and traditional PIV data processing is prerequisite to a meaningful description of SPOF PIV processing. In PIV, a pulsed laser is used to illuminate a substantially planar region of a flowing fluid in which particles are entrained. An electronic camera records digital images of the particles at two instants of time. The components of velocity of the fluid in the illuminated plane can be obtained by determining the displacements of particles between the two illumination pulses. The objective in PIV data processing is to compute the particle displacements from the digital image data. In traditional PIV data processing, to which the present innovation applies, the two images are divided into a grid of subregions and the displacements determined from cross-correlations between the corresponding sub-regions in the first and second images. The cross-correlation process begins with the calculation of the Fourier transforms (or fast Fourier transforms) of the subregion portions of the images. The Fourier transforms from the corresponding subregions are multiplied, and this product is inverse Fourier transformed, yielding the cross-correlation intensity distribution. The average displacement of the particles across a subregion results in a displacement of the correlation peak from the center of the correlation plane. The velocity is then computed from the displacement of the correlation peak and the time between the recording of the two images. The process as described thus far is performed for all the subregions. The resulting set of velocities in grid cells amounts to a velocity vector map of the flow field recorded on the image plane. In traditional PIV processing, surface flare light and bright background light give rise to a large, broad correlation peak, at the center of the correlation plane, that can overwhelm the true particle- displacement correlation peak. This has made it necessary to resort to tedious image-masking and background-subtraction procedures to recover the relatively small amplitude particle-displacement correlation peak. SPOF is a variant of phase-only filtering (POF), which, in turn, is a variant of matched spatial filtering (MSF). In MSF, one projects a first image (denoted the input image) onto a second image (denoted the filter) as part of a computation to determine how much and what part of the filter is present in the input image. MSF is equivalent to cross-correlation. In POF, the frequency-domain content of the MSF filter is modified to produce a unitamplitude (phase-only) object. POF is implemented by normalizing the Fourier transform of the filter by its magnitude. The advantage of POFs is that they yield correlation peaks that are sharper and have higher signal-to-noise ratios than those obtained through traditional MSF. In the SPOF, these benefits of POF can be extended to PIV data processing. The SPOF yields even better performance than the POF approach, which is uniquely applicable to PIV type image data. In SPOF as now applied to PIV data processing, a subregion of the first image is treated as the input image and the corresponding subregion of the second image is treated as the filter. The Fourier transforms from both the firs and second- image subregions are normalized by the square roots of their respective magnitudes. This scheme yields optimal performance because the amounts of normalization applied to the spatial-frequency contents of the input and filter scenes are just enough to enhance their high-spatial-frequency contents while reducing their spurious low-spatial-frequency content. As a result, in SPOF PIV processing, particle-displacement correlation peaks can readily be detected above spurious background peaks, without need for masking or background subtraction.
Author
PARTICLE IMAGE VELOCIMETRY; IMAGE FILTERS; SPATIAL FILTERING; MATCHED FILTERS; HIGH FREQUENCIES; FLOW DISTRIBUTION; FAST FOURIER TRANSFORMATIONS; DIGITAL DATA; SIGNAL TO NOISE RATIOS; PULSED LASERS
20090017555 California Inst. of Tech., Pasadena, CA, United States
Fuel-Cell Electrolytes Based on Organosilica Hybrid Proton Conductors
Narayan, Sri R.; Yen, Shiao-Pin S.; NASA Tech Briefs, May 2008; May 2008; pp. 2; In English
Report No.(s): NPO-40228; Copyright; Avail.: CASI: A01, Hardcopy
A new membrane composite material that combines an organosilica proton conductor with perfluorinated Nafion material to achieve good proton conductivity and high-temperature performance for membranes used for fuel cells in stationary, transportation, and portable applications has been developed. To achieve high proton conductivities of the order of 10(exp -1)S/cm over a wide range of temperatures, a composite membrane based on a new class of mesoporous, proton-conducting, hydrogen-bonded organosilica, used with Nafion, will allow for water retention and high proton conductivity over a wider range of temperatures than currently offered by Nafion alone. At the time of this reporting, this innovation is at the concept level. Some of the materials and processes investigated have shown good proton conductivity, but membranes have not yet been prepared and demonstrated.
Author
FUEL CELLS; ELECTROLYTES; PROTONS; CONDUCTORS; COMPOSITE MATERIALS; MEMBRANES; HIGH TEMPERATURE
20090018046 NASA Marshall Space Flight Center, Huntsville, AL, United States
Pin Tool Geometry Effects in Friction Stir Welding
Querin, J. A.; Rubisoff, H. A.; Schneider, J. A.; February 15, 2009; In English; The Minerals, Metals and Materials Society (TMS) Conference, 15-19 Feb. 2009, San Francisco, CA, United States; Original contains color and black and white illustrations
Report No.(s): M09-0323; Copyright; Avail.: CASI: A03, Hardcopy
In friction stir welding (FSW) there is significant evidence that material can take one of two different flow paths when being displaced from its original position in front of the pin tool to its final position in the wake of the weld. The geometry of the pin tool, along with the process parameters, plays an important role in dictating the path that the material takes. Each flow path will impart a different thermomechanical history on the material, consequently altering the material microstructure and subsequent weld properties. The intention of this research is to isolate the effect that different pin tool attributes have on the flow paths imparted on the FSWed material. Based on published weld tool geometries, a variety of weld tools were fabricated and used to join AA2219. Results from the tensile properties and microstructural characterization will be presented.
Author
CHARACTERIZATION; FRICTION STIR WELDING; PINS
20090018047 NASA Glenn Research Center, Cleveland, OH, United States
History of Thermal Barrier Coatings for Gas Turbine Engines: Emphasizing NASA's Role from 1942 to 1990
Miller, Robert A.; March 2009; In English; Thermal Barrier Coatings II, Engineering Conference International, 12-17 Aug. 2007, KlosterIree, Germany; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 877868.02.07.03.05.01
Report No.(s): NASA/TM-2009-215459; E-16683; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090018047
NASA has played a central role in the development of thermal barrier coatings (TBCs) for gas turbine applications. This report discusses the history of TBCs emphasizing the role NASA has played beginning with (1) frit coatings in the 1940s and 1950s; (2) thermally sprayed coatings for rocket application in the 1960s and early 1970s; (3) the beginnings of the modern era of turbine section coatings in the mid 1970s; and (4) failure mechanism and life prediction studies in the 1980s and 1990s. More recent efforts are also briefly discussed.
Author
THERMAL CONTROL COATINGS; PROTECTIVE COATINGS; SPRAYED COATINGS; GAS TURBINE ENGINES
20090018048 NASA Glenn Research Center, Cleveland, OH, United States
Validation of Finite Element Crash Test Dummy Models for Predicting Orion Crew Member Injuries During a Simulated Vehicle Landing
Tabiei, Al; Lawrence, Charles; Fasanella, Edwin L.; March 2009; In English; 10th International LS-DYNA Users Conference, 8-10 Jun. 2008, Dearborn, MI, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 510505.05.03.07.13
Report No.(s): NASA/TM-2009-215476; E-16677; Copyright; Avail.: CASI: A03, Hardcopy
A series of crash tests were conducted with dummies during simulated Orion crew module landings at the Wright-Patterson Air Force Base. These tests consisted of several crew configurations with and without astronaut suits. Some test results were collected and are presented. In addition, finite element models of the tests were developed and are presented. The finite element models were validated using the experimental data, and the test responses were compared with the computed results. Occupant crash data, such as forces, moments, and accelerations, were collected from the simulations and compared with injury criteria to assess occupant survivability and injury. Some of the injury criteria published in the literature is summarized for completeness. These criteria were used to determine potential injury during crew impact events.
Author
LANDING SIMULATION; SPACECRAFT LANDING; SPACECRAFT MODULES; INJURIES; ASTRONAUTS; CREW EXPLORATION VEHICLE; SPACECREWS; DUMMIES
20090018051 NASA Johnson Space Center, Houston, TX, United States
Megafans as Hydrous Environments
Wilkinson, M. Justin; Miller, R. McG.; Allen, C. C.; Kreslavsky, M. H.; Eckardt, F.; [2009]; In English; Modeling Martian Hydrous Environments, 1-3 Jun. 2009, Houston, TX, United States; Original contains black and white illustrations
Contract(s)/Grant(s): NAS9-19100
Report No.(s): JSC-CN-18165; Copyright; Avail.: CASI: A01, Hardcopy
The mesoscale sedimentary environment known as the megafan, is a low-angle, partial cone of fluvial sediment generated where a river enters an unconfined basin where it begins the process of avulsing over wide areas. In shifting to different positions, the river lays down a partial cone of sediment and establishes a characteristic radial pattern of paleo courses. The apparent paucity of sedimentary bodies obviously tied to martian outflow channels may also relate to the difficulty of recognition due to their sheer size and featurelessness. However, the existence of megafans on Mars is being examined now that their ubiquity and characteristics on Earth are better understood. Accordingly we suggest two likely candidates on Mars: Maja Valles fluvial cone and Amazonis Planitia fluvial sedimentary bodies. Two cryptic examples from Amazonis Planitia may be important for understanding subsurface hydrous accumulation. For at least some of its history, discharges from Mangala Valles likely resulted in megafans. Distances from the end of Mangala Valles to the northern (low) margin of the planitia are very large, a fact that has suggested that fluvial emplacement was unlikely. However, the megafan model shows that long megafan radii are indeed feasible. It has been suggested further that discharge from Labou Vallis (8.5S 154.5W) must have led to fluvial sedimentation in the planitia. We suggest that during locally non-lacustrine/ocean phases, this sedimentation would have occurred in the form of megafans. However, the megafan model shows that long megafan radii are indeed feasible. It has been suggested further that discharge from Labou Vallis (8.5S 154.5W) must have led to fluvial sedimentation in the planitia. We suggest that during locally non-lacustrine/ocean phases, this sedimentation would have occurred in the form of megafans. Megafans emanating from Marte, Mangala and Labou valles have probably contributed to hydrous near-subsurface environments--in their distal reaches, i.e. along the northern, eastern and southeastern margins of Amazonis Planitia at various times. Following a new terrestrial analog, we conclude groundwater has at times accumulated preferentially beneath distal slopes of the Maja Valles feature, and along the northern, eastern and southeastern margins of Amazonis Planitia.
Derived from text
MARS (PLANET); MARS SURFACE; SEDIMENTS; RIVER BASINS; RIVERS; EXTRATERRESTRIAL WATER
20090018053 Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA, United States
Analytical Solutions and Approximations for the Equation ydy/dx = (ay+b) h(x) with Applications to Drift-Diffusion
Edmonds, Larry D.; March 31, 2009; In English; Original contains black and white illustrations
Contract(s)/Grant(s): NAS7-03001WU 07119.1.77
Report No.(s): JPL-Publ-09-13; Copyright; Avail.: CASI: A05, Hardcopy
Avail Online: http://hdl.handle.net/2014/41263
The problem considered is y(x)dy(x)/dx=(a y(x)+B)h(x) subject to a point-value condition. In principle, this problem is solvable using elementary textbook methods. In practice, two difficulties are encountered. The first difficulty is associated with existence and uniqueness of solutions. The second difficulty is that exact solutions to the differential equation are expressed as solutions to transcendental algebraic equations that require numerical root-finding algorithms. This paper avoids the first difficulty by confining attention to uniform solutions, defined as solutions that do not change sign. The second difficulty is avoided by finding accurate, yet simple, approximations for the exact solutions. These approximations are derived for the physical application of charge-carrier drift-diffusion in a quasi-neutral semiconductor material. Exact results are also given, showing that a sufficiently large carrier generation rate creates a sensitive volume in the quasi-neutral region. However, the sensitive volume is a symbolic model and has limited applicability. An alternate model that is a more literal description of charge-collection physics is ambipolar diffusion with a cutoff.
Author
DIFFERENTIAL EQUATIONS; SOLUTION; AMBIPOLAR DIFFUSION; CHARGE EFFICIENCY; SEMICONDUCTORS (MATERIALS); ELECTRICAL PROPERTIES; PHYSICS
20090018054 NASA Marshall Space Flight Center, Huntsville, AL, United States
Interface Shape Control Using Localized Heating during Bridgman Growth
Volz, M.P.; Mazuruk, K.; Aggarwal, M.D.; Croll, A.; Journal of Crystal Growth; [2008]; vol. Volume 311; issue Issue 8; pp. 2321-232; In English; Original contains black and white illustrations
Report No.(s): M09-0249; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://dx.doi.org/10.1016/j.jcrysgro.2009.02.019
Numerical calculations were performed to assess the effect of localized radial heating on the melt-crystal interface shape during vertical Bridgman growth. System parameters examined include the ampoule, melt and crystal thermal conductivities, the magnitude and width of localized heating, and the latent heat of crystallization. Concave interface shapes, typical of semiconductor systems, could be flattened or made convex with localized heating. Although localized heating caused shallower thermal gradients ahead of the interface, the magnitude of the localized heating required for convexity was less than that which resulted in a thermal inversion ahead of the interface. A convex interface shape was most readily achieved with ampoules of lower thermal conductivity. Increasing melt convection tended to flatten the interface, but the amount of radial heating required to achieve a convex interface was essentially independent of the convection intensity.
Author
BRIDGMAN METHOD; CRYSTALLIZATION; SHAPE CONTROL; COMPUTERIZED SIMULATION; COMPUTATIONAL CHEMISTRY; MATHEMATICAL MODELS; HEAT TRANSMISSION
20090018058 NASA Marshall Space Flight Center, Huntsville, AL, United States
A Closer Look at Solar Wind Sputtering of Lunar Surface Materials
Barghouty, A. F.; Adams, J. H., Jr.; Meyer, F.; Mansur, L.; Reinhold, C.; December 15, 2008; In English; American Geophysical Union Fall Meeting 2008, 15-19 Dec. 2008, San Francisco, CA, United States; Original contains color illustrations
Report No.(s): Poster No. P31B-1402; M09-0279; Copyright; Avail.: CASI: A01, Hardcopy
Solar-wind induced potential sputtering of the lunar surface may be a more efficient erosive mechanism than the "standard" kinetic (or physical) sputtering. This is partly based on new but limited laboratory measurements which show marked enhancements in the sputter yields of slow-moving, highly-charged ions impacting oxides. The enhancements seen in the laboratory can be orders of magnitude for some surfaces and highly charged incident ions, but seem to depend very sensitively on the properties of the impacted surface in addition to the fluence, energy and charge of the impacting ion. For oxides, potential sputtering yields are markedly enhanced and sputtered species, especially hydrogen and light ions, show marked dependence on both charge and dose.
Derived from text
IONS; LUNAR SURFACE; SOLAR WIND; SPUTTERING; REGOLITH; LUNAR GEOLOGY
20090018063 NASA Marshall Space Flight Center, Huntsville, AL, United States
Marshall Space Flight Center Engineering Directorate Overview: Launching the Future of Science and Exploration
Miley, Steven C.; February 19, 2009; In English; NASA Marshall Small Business Aliance Quarterly Meeting, 19 Feb. 2009, Huntsville, AL, United States; Original contains color illustrations
Report No.(s): M09-0324; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090018063
The Marshall Small Business Association (MSBA) serves as a central point of contact to inform and educate small businesses interested in pursuing contracting and subcontracting opportunities at the Marshall Space Flight Center. The MSBA meets quarterly to provide industry with information about how to do business with Marshall and to share specific information about Marshall s mission, which allows private businesses to envision how they might contribute. For the February 19 meeting, the Engineering Directorate will give an overview of its unique capabilities and how it is organized to provide maximum support for the programs and projects resident at Marshall, for example, the Space Shuttle Propulsion Office, Ares Projects Office, and Science and Mission Systems Office. This briefing provides a top-level summary of the work conducted by Marshall s largest organization, while explaining how resources are deployed to perform the volume of work under Marshall s purview.
Author
INDUSTRIES; CONTRACTS; GOVERNMENT/INDUSTRY RELATIONS; NASA PROGRAMS
20090018064 NASA Marshall Space Flight Center, Huntsville, AL, United States
Production of Oxygen from Lunar Regolith using Molten Oxide Electrolysis
Sibille, Laurent; Sadoway, Donald R.; Sirk, Aislinn; Tripathy, Prabhat; Melendez, Orlando; Standish, Evan; Dominquez, Jesus A.; Stefanescu, Doru M.; Curreri, Peter A.; Poizeau, Sophie; February 26, 2009; In English; Space Propulsion and Energy Sciences International Forum, 26 Feb. 2009, Huntsville, AL, United States; Original contains color and black and white illustrations
Report No.(s): M09-0370; Copyright; Avail.: CASI: A03, Hardcopy
This slide presentation reviews the possible use of molten oxide electrolysis to extract oxygen from the Lunar Regolith. The presentation asserts that molten regolith electrolysis has advanced to be a useful method for production of oxygen and metals in situ on the Moon. The work has demonstrated an 8 hour batch of electrolysis at 5 amps using Iridium inert anodes.
CASI
ELECTROLYSIS; LUNAR ROCKS; REGOLITH; IN SITU RESOURCE UTILIZATION; OXYGEN PRODUCTION; OXIDES; OXYGEN
20090018067 NASA Glenn Research Center, Cleveland, OH, United States
Use of the X-Band Radar to Support the Detection of In-Flight Icing Hazards by the NASA Icing Remote Sensing System
Serke, David J.; Politovich, Marcia K.; Reehorst, Andrew L.; Gaydos, Andrew; March 2009; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 609866.02.07.03.04
Report No.(s): NASA/TM-2009-215503; E-16691; Copyright; Avail.: CASI: A03, Hardcopy
The Alliance Icing Research Study-II (AIRS-II) field program was conducted near Montreal, Canada during the winter of 2003. The NASA Icing Remote Detection System (NIRSS) was deployed to detect in-flight icing hazards and consisted of a vertically pointing multichannel radiometer, a ceilometer and an x-band cloud radar. The radiometer was used to derive atmospheric temperature soundings and integrated liquid water, while the ceilometer and radar were used only to define cloud boundaries. The purpose of this study is to show that the radar reflectivity profiles from AIRS-II case studies could be used to provide a qualitative icing hazard.
Author
ICE FORMATION; REMOTE SENSING; SUPERHIGH FREQUENCIES; RADAR DETECTION; REFLECTANCE; METEOROLOGICAL RADAR; CLOUD PHYSICS
20090018068 NASA Glenn Research Center, Cleveland, OH, United States
Stirling Convertor Control for a Concept Rover at NASA Glenn Research Center
Blaze-Dugala, Gina M.; March 2009; In English; 6th International Energy Conversion Engineering Conference (IECEC-2008), 28-30 Jul. 2008, Cleveland, OH, United States; Original contains color illustrations
Contract(s)/Grant(s): WBS 138494.04.01.01
Report No.(s): NASA/TM-2009-215513; E-16812; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090018068
The U.S. Department of Energy (DOE), Lockheed Martin Space Systems Company (LMSSC), Sunpower Inc., and NASA Glenn Research Center (GRC) have been developing an Advanced Stirling Radioisotope Generator (ASRG) for potential use as an electric power system for space science missions. This generator would make use of the free-piston Stirling cycle to achieve higher conversion efficiency than currently used alternatives. NASA GRC initiated an experiment with an ASRG simulator to demonstrate the functionality of a Stirling convertor on a mobile application, such as a rover. The ASRG simulator made use of two Advanced Stirling Convertors to convert thermal energy from a heat source to electricity. The ASRG simulator was designed to incorporate a minimum amount of support equipment, allowing integration onto a rover powered directly by the convertors. Support equipment to provide control was designed including a linear AC regulator controller, constant power controller, and Li-ion battery charger controller. The ASRG simulator is controlled by a linear AC regulator controller. The rover is powered by both a Stirling convertor and Li-ion batteries. A constant power controller enables the Stirling convertor to maintain a constant power output when additional power is supplied by the Li-ion batteries. A Li-ion battery charger controller limits the charging current and cut off current of the batteries. This paper discusses the design, fabrication, and implementation of these three controllers.
Author
ENERGY CONVERSION EFFICIENCY; STIRLING CYCLE; RADIOISOTOPE HEAT SOURCES; ELECTRIC GENERATORS; ELECTRIC BATTERIES; BATTERY CHARGERS; CONTROLLERS
20090018069 NASA Glenn Research Center, Cleveland, OH, United States
Fission Surface Power Technology Development Status
Palac, Donald T.; Mason, Lee S.; Harlow, Scott; March 2009; In English; 47th Aerospace Sciences Meeting, 5-8 Jan. 2009, Orlando, FL, United States; Original contains color illustrations
Contract(s)/Grant(s): WBS 463169.01.03.01.01
Report No.(s): NASA/TM-2009-215602; AIAA-2008-7812; E-16892; Copyright; Avail.: CASI: A03, Hardcopy
With the potential future deployment of a lunar outpost there is expected to be a clear need for a high-power, lunar surface power source to support lunar surface operations independent of the day-night cycle, and Fission Surface Power (FSP) is a very effective solution for power levels above a couple 10 s of kWe. FSP is similarly enabling for the poorly illuminated surface of Mars. The power levels/requirements for a lunar outpost option are currently being studied, but it is known that cost is clearly a predominant concern to decision makers. This paper describes the plans of NASA and the DOE to execute an affordable fission surface power system technology development project to demonstrate sufficient technology readiness of an affordable FSP system so viable and cost-effective FSP system options will be available when high power lunar surface system choices are expected to be made in the early 2010s.
Author
NUCLEAR FISSION; NUCLEAR ELECTRIC POWER GENERATION; LUNAR BASES; LUNAR BASED EQUIPMENT; MARS BASES
20090018336 NASA Langley Research Center, Hampton, VA, United States
The Development of Directional Decohesion Finite Elements for Multiscale Failure Analysis of Metallic Polycrystals
Saether, Erik; Glaessgen, Edward H.; April 2009; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 698259.02.07.07.03.01
Report No.(s): NASA/TM-2009-215715; L-19610; LF99-8507; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090018336
Atomistic simulations of intergranular fracture have indicated that grain-scale crack growth in polycrystalline metals can be direction dependent. At these material length scales, the atomic environment greatly influences the nature of intergranular crack propagation, through either brittle or ductile mechanisms, that are a function of adjacent grain orientation and direction of crack propagation. Methods have been developed to obtain cohesive zone models (CZM) directly from molecular dynamics simulations. These CZMs may be incorporated into decohesion finite element formulations to simulate fracture at larger length scales. A new directional decohesion element is presented that calculates the direction of Mode I opening and incorporates a material criterion for dislocation emission based on the local crystallographic environment to automatically select the CZM that best represents crack growth. The simulation of fracture in 2-D and 3-D aluminum polycrystals is used to illustrate the effect of parameterized CZMs and the effectiveness of directional decohesion finite elements.
Author
FINITE ELEMENT METHOD; COHESION; CRACK PROPAGATION; CRACKING (FRACTURING); POLYCRYSTALS
Additions to the NASA Aeronautics and Space Database as of 05/27/2009
20090019005 NASA Glenn Research Center, Cleveland, OH, United States
A Brief Survey of Media Access Control, Data Link Layer, and Protocol Technologies for Lunar Surface Communications
Wallett, Thomas M.; April 2009; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 645846.02.07.03.05
Report No.(s): NASA/TM-2009-215295; E-16565; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090019005
This paper surveys and describes some of the existing media access control and data link layer technologies for possible application in lunar surface communications and the advanced wideband Direct Sequence Code Division Multiple Access (DSCDMA) conceptual systems utilizing phased-array technology that will evolve in the next decade. Time Domain Multiple Access (TDMA) and Code Division Multiple Access (CDMA) are standard Media Access Control (MAC) techniques that can be incorporated into lunar surface communications architectures. Another novel hybrid technique that is recently being developed for use with smart antenna technology combines the advantages of CDMA with those of TDMA. The relatively new and sundry wireless LAN data link layer protocols that are continually under development offer distinct advantages for lunar surface applications over the legacy protocols which are not wireless. Also several communication transport and routing protocols can be chosen with characteristics commensurate with smart antenna systems to provide spacecraft communications for links exhibiting high capacity on the surface of the Moon. The proper choices depend on the specific communication requirements.
Author
CODE DIVISION MULTIPLE ACCESS; DATA LINKS; LUNAR SURFACE; TIME DIVISION MULTIPLE ACCESS; WIRELESS COMMUNICATION; SPACECRAFT COMMUNICATION; PHASED ARRAYS; ANTENNA DESIGN; ACCESS CONTROL; CONTROL SYSTEMS DESIGN
20090019007 NASA Glenn Research Center, Cleveland, OH, United States
Vapor-Gas Bubble Evolution and Growth in Extremely Viscous Fluids Under Vacuum
Kizito, John; Balasubramaniam, R.; Nahra, Henry; Agui, Juan; Truong, Duc; March 2008; In English; 47th Aerospace Sciences Meeting and Exhibit, 5-8 Jan. 2009, Orlando, FL, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 825080.01.02.20.01
Report No.(s): NASA/TM-2009-215606; AIAA-2009-1147; E-16896; Copyright; Avail.: CASI: A03, Hardcopy
Formation of vapor and gas bubbles and voids is normal and expected in flow processes involving extremely viscous fluids in normal gravity. Practical examples of extremely viscous fluids are epoxy-like filler materials before the epoxy fluids cure to their permanent form to create a mechanical bond between two substrates. When these fluids flow with a free liquid interface exposed to vacuum, rapid bubble expansion process may ensue. Bubble expansion might compromise the mechanical bond strength. The potential sources for the origin of the gases might be incomplete out-gassing process prior to filler application; regasification due to seal leakage in the filler applicator; and/or volatiles evolved from cure reaction products formed in the hardening process. We embarked on a study that involved conducting laboratory experiments with imaging diagnostics in order to deduce the seriousness of bubbling caused by entrained air and volatile fluids under space vacuum and low gravity environment. We used clear fluids with the similar physical properties as the epoxy-like filler material to mimic the dynamics of bubbles. Another aspect of the present study was to determine the likelihood of bubbling resulting from dissolved gases nucleating from solution. These experimental studies of the bubble expansion are compared with predictions using a modified Rayleigh- Plesset equation, which models the bubble expansion.
Author
BUBBLES; GAS EVOLUTION; DISSOLVED GASES; VISCOUS FLUIDS; VACUUM; REACTION PRODUCTS; MICROGRAVITY; GRAVITATION; NUCLEATION
20090019016 Universities Space Research Association, Houston, TX, United States
Luna: What Did We Learn and What Should We Expect?
Wallace, William T.; April 23, 2009; In English; UTMB National Student Research Forum, 23-25 Apr. 2009, Galveston, TX, United States; Original contains color and black and white illustrations
Report No.(s): JSC-18203; Copyright; Avail.: CASI: A04, Hardcopy
This presentation presents a look at the space program's background prior to lunar exploration and highlights the Apollo program and lessons learned from lunar exploration. The possibilities of exposures and difficulties attributed to lunar dust are described, including obscured vision, clogged equipment, coated surfaces, and inhalation, among others. A lunar dust simulant is proposed to support preliminary studies. Lunar dust is constantly activated by meteorite lunar dust, UV radiation and elements of solar wind - this active dust could produce reactive species. Methods of deactivation must be determined before new lunar missions, but first we must understand how to reactivate dust on Earth. Activation methods tested and described here include crushing/grinding or UV activation. Grinding time has a direct effect on amount of hydroxyl radicals produced upon addition of ground quartz to a solution. An increase in hydroxyl production was also seen for a lunar simulant with increased grinding.
Derived from text
LUNAR EXPLORATION; LESSONS LEARNED; LUNAR DUST; RISK ASSESSMENT; EXPOSURE; ASTRONAUTS; AEROSPACE MEDICINE
20090019024 NASA Marshall Space Flight Center, Huntsville, AL, United States
Accreting X-ray Pulsars
Wilson-Hodge, Colleen A.; January 05, 2009; In English; 213th Meeting of the American Astronomical Society, 4-8 Jan. 2009, Long Beach, CA, United States; Original contains color and black and white illustrations
Report No.(s): M09-0227; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090019024
This presentation describes the behavior of matter in environments with extreme magnetic and gravitational fields, explains the instability/stability of accretion disks in certain systems, and discusses how emergent radiation affects accretion flow. Magnetic field measurements are obtained by measuring the lowest cyclotron absorption line energy, observing the cutoff of accretion due to centrifugal inhibition and measuring the spin-up rate at high luminosity.
Derived from text
PULSARS; ACCRETION DISKS; ASTROPHYSICS
20090019025 NASA Marshall Space Flight Center, Huntsville, AL, United States
Dispersion-Enhanced Laser Gyroscope
Smith, David D.; Chang, Hongrok; Arissian, L.; Diels, J. C.; Physical Review A; November 2008; vol. Volume 78; issue Issue 5; In English; Original contains color and black and white illustrations
Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://dx.doi.org/10.1103/PhysRevA.78.053824
We analyze the effect of a highly dispersive element placed inside a modulated optical cavity on the frequency and amplitude of the output modulation to determine the conditions for enhanced gyroscopic sensitivities. The element is treated as both a phase and amplitude filter, and the time-dependence of the cavity field is considered. Both atomic gases (two-level and multi-level) and optical resonators (single and coupled) are considered and compared as dispersive elements. We find that it is possible to simultaneously enhance the gyro scale factor sensitivity and suppress the dead band by using an element with anomalous dispersion that has greater loss at the carrier frequency than at the side-band frequencies, i.e., an element that simultaneously pushes and intensifies the perturbed cavity modes, e.g. a two-level absorber or an under-coupled optical resonator. The sensitivity enhancement is inversely proportional to the effective group index, becoming infinite at a group index of zero. However, the number of round trips required to reach a steady-state also becomes infinite when the group index is zero (or two). For even larger dispersions a steady-state cannot be achieved, and nonlinear dynamic effects such as bistability and periodic oscillations are predicted in the gyro response.
Author
LASER GYROSCOPES; LASER CAVITIES; AMPLITUDE MODULATION; FREQUENCY MODULATION; LASER OUTPUTS; PHASE SHIFT; LASER MODES
20090019027 NASA Glenn Research Center, Cleveland, OH, United States
Synthesis Methods, Microscopy Characterization and Device Integration of Nanoscale Metal Oxide Semiconductors for Gas Sensing in Aerospace Applications
VanderWal, Randy L.; Berger, Gordon M.; Kulis, Michael J.; Hunter, Gary W.; Xu, Jennifer C.; Evans, Laura J.; March 2009; In English; Original contains black and white illustrations
Contract(s)/Grant(s): WBS 441261.04.01.01.03.09
Report No.(s): NASA/TM-2009-215607; E-16639-2; Copyright; Avail.: CASI: A03, Hardcopy
A comparison is made between SnO2, ZnO, and TiO2 single-crystal nanowires and SnO2 polycrystalline nanofibers for gas sensing. Both nanostructures possess a one-dimensional morphology. Different synthesis methods are used to produce these materials: thermal evaporation-condensation (TEC), controlled oxidation, and electrospinning. Advantages and limitations of each technique are listed. Practical issues associated with harvesting, purification, and integration of these materials into sensing devices are detailed. For comparison to the nascent form, these sensing materials are surface coated with Pd and Pt nanoparticles. Gas sensing tests, with respect to H2, are conducted at ambient and elevated temperatures. Comparative normalized responses and time constants for the catalyst and noncatalyst systems provide a basis for identification of the superior metal-oxide nanostructure and catalyst combination. With temperature-dependent data, Arrhenius analyses are made to determine an activation energy for the catalyst-assisted systems.
Author
CATALYSTS; GAS ANALYSIS; METAL OXIDE SEMICONDUCTORS; NANOPARTICLES; NANOSTRUCTURES (DEVICES); NANOWIRES; POLYCRYSTALS; NANOTECHNOLOGY
20090019028 NASA Glenn Research Center, Cleveland, OH, United States
802.16e System Profile for NASA Extra-Vehicular Activities
Foore, Lawrence R.; Chelmins, David T.; Nguyen, Hung D.; Downey, Joseph A.; Finn, Gregory G.; Cagley, Richard E.; Bakula, Casey J.; April 2009; In English; International Workshop on Lunar Surface Wireless Communications and Navigation, 13-17 Oct. 2008, Berlin, Germany; Original contains color and black and white illustrations
Contract(s)/Grant(s): WS 903184.04.03.02.01
Report No.(s): NASA/TM-2009-215624; E-16811; Copyright; Avail.: CASI: A03, Hardcopy
This report identifies an 802.16e system profile that is applicable to a lunar surface wireless network, and specifically for meeting extra-vehicular activity (EVA) data flow requirements. EVA suit communication needs are addressed. Design-driving operational scenarios are considered. These scenarios are then used to identify a configuration of the 802.16e system (system profile) that meets EVA requirements, but also aim to make the radio realizable within EVA constraints. Limitations of this system configuration are highlighted. An overview and development status is presented by Toyon Research Corporation concerning the development of an 802.16e compatible modem under NASA s Small Business Innovative Research (SBIR) Program. This modem is based on the recommended system profile developed as part of this report. Last, a path forward is outlined that presents an evolvable solution for the EVA radio system and lunar surface radio networks. This solution is based on a custom link layer, and 802.16e compliant physical layer compliant to the identified system profile, and a later progression to a fully interoperable 802.16e system.
Author
EXTRAVEHICULAR ACTIVITY; LUNAR SURFACE; SYSTEMS ENGINEERING; WIRELESS COMMUNICATION; SPACECRAFT COMMUNICATION; RADIO COMMUNICATION
Additions to the NASA Aeronautics and Space Database as of 05/28/2009
20090019072 NASA Langley Research Center, Hampton, VA, United States
International Space Station/Shuttle "Flip" Maneuver for Thermal Protection System Repair Consultation Report
Dennehy, Cornelius J.; Bauer, Frank; Bilimoria, Karl D.; Dillman, Dennis B.; Gilbert, Michael G.; Hagopian, Michael; Hua, Tuyen; Legget, Jay; Maghami, Peiman G.; Mangus, David J.; Starin, Scott R.; April 2009; In English; Original contains color illustrations
Contract(s)/Grant(s): WBS 869021.06.07.03.99
Report No.(s): NASA/TM-2009-215710; NESC-RP-05-88/04-034-E; L-19649; LF99-8642; No Copyright; Avail.: CASI: A04, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090019072
The intent of this Technical Consultation Report is to document the finding and recommendations of the NESC Orbiter Repair Maneuver (ORM) Peer Review conducted at NASA s Johnson Space Center (JSC) with the ORM Working Group (WG) over the period 8-10 June 2005.
Author
INTERNATIONAL SPACE STATION; THERMAL PROTECTION
20090019073 NASA Ames Research Center, Moffett Field, CA, United States
Bounded Linear Stability Margin Analysis of Nonlinear Hybrid Adaptive Control
Nguyen, Nhan T.; Boskovic, Jovan D.; June 11, 2008; In English; American Control Conference, 11-13 Jun. 2008, Seattle, WA, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 457280.02.07.01.01
Report No.(s): ARC-E-DAA-TN119; Copyright; Avail.: CASI: A02, Hardcopy
This paper presents a bounded linear stability analysis for a hybrid adaptive control that blends both direct and indirect adaptive control. Stability and convergence of nonlinear adaptive control are analyzed using an approximate linear equivalent system. A stability margin analysis shows that a large adaptive gain can lead to a reduced phase margin. This method can enable metrics-driven adaptive control whereby the adaptive gain is adjusted to meet stability margin requirements.
Author
ADAPTIVE CONTROL; LINEAR SYSTEMS; STABILITY TESTS; APPROXIMATION
20090019082 NASA Johnson Space Center, Houston, TX, United States
Operations to Research: Communication of Lessons Learned
Fogarty, Jennifer; April 21, 2009; In English; 80th Annual Scientific Meeting of the Aerospace Medical Association Meeting, 4-7 May 2009, Los Angeles, CA, United States; Original contains color and black and white illustrations
Report No.(s): JSC-CN-18236; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090019082
This presentation explores ways to build upon previous spaceflight experience and communicate this knowledge to prepare for future exploration. An operational approach is highlighted, focusing on selection and retention standards (disease screening and obtaining medical histories); pre-, in-, and post-flight monitoring (establishing degrees of bone loss, skeletal muscle loss, cardiovascular deconditioning, medical conditions, etc.); prevention, mitigation, or treatment (in-flight countermeasures); and, reconditioning, recovery, and reassignment (post-flight training regimen, return to pre-flight baseline and flight assignment). Experiences and lessons learned from the Apollo, Skylab, Shuttle, Shuttle-Mir, International Space Station, and Orion missions are outlined.
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SPACE FLIGHT; LESSONS LEARNED; BIOASTRONAUTICS; AEROSPACE MEDICINE; INFORMATION FLOW
20090019087 NASA Johnson Space Center, Houston, TX, United States
Renal Stone Risk during Spaceflight: Assessment and Countermeasure Validation
Whitson, Peggy A.; Pietrzyk, Robert A.; Jones, Jeffery A.; Sams, Clarence F.; Hudson, Ed K.; Nelman-Gonzalez, Mayra; May 03, 2009; In English; Aerospace Medical Association Meeting, 3-7 May 2009, Los Angeles, CA, United States; Original contains color and black and white illustrations
Report No.(s): JSC-CN-18261; Copyright; Avail.: CASI: A03, Hardcopy
NASA's Vision for Space Exploration centers on exploration class missions including the goals of returning to the moon and landing on Mars. One of NASA's objectives is to focus research on astronaut health and the development of countermeasures that will protect crewmembers during long duration voyages. Exposure to microgravity affects human physiology and results in changes in the urinary chemical composition favoring urinary supersaturation and an increased risk of stone formation. Nephrolithiasis is a multifactorial disease and development of a renal stone is significantly influenced by both dietary and environmental factors. Previous results from long duration Mir and short duration Shuttle missions have shown decreased urine volume, pH, and citrate levels and increased calcium. Citrate, an important inhibitor of calcium-containing stones, binds with urinary calcium reducing the amount of calcium available to form stones. Citrate inhibits renal stone recurrence by preventing crystal growth, aggregation, and nucleation and is one of the most common therapeutic agents used to prevent stone formation. Methods: Thirty long duration crewmembers (29 male, 1 female) participated in this study. 24-hour urines were collected and dietary monitoring was performed pre-, in-, and postflight. Crewmembers in the treatment group received two potassium citrate (KCIT) pills, 10 mEq/pill, ingested daily beginning 3 days before launch, all in-flight days and through 14 days postflight. Urinary biochemical and dietary analyses were completed. Results: KCIT treated subjects exhibited decreased urinary calcium excretion and maintained the levels of calcium oxalate supersaturation risk at their preflight levels. The increased urinary pH levels in these subjects reduced the risk of uric acid stones. Discussion: The current study investigated the use of potassium citrate as a countermeasure to minimize the risk of stone formation during ISS missions. Results suggest that supplementation with potassium citrate decreases the risk of stone formation during and immediately after spaceflight.
Author
KIDNEY STONES; RISK ASSESSMENT; RISK MANAGEMENT; AEROSPACE MEDICINE; LONG DURATION SPACE FLIGHT; INTERNATIONAL SPACE STATION
20090019094 NASA Marshall Space Flight Center, Huntsville, AL, United States
Flux of Kilogram-Sized Meteoroids from Lunar Impact Monitoring
Suggs, Robert; Suggs, Ron; Cooke, William; McNamara, Heather; Diekmann, Anne; Moser, Danielle; Swift, Wesley; October 10, 2008; In English; 40th Annual Meeting of the Division for Planetary Sciences of the American Astronomical Society, 10 - 15 Oct. 2008, New York, United States
Report No.(s): MSFC-2154; Copyright; Avail.: CASI: A01, Hardcopy
Routine lunar impact monitoring has harvested over 110 impacts in 2 years of observations using 0.25, 0.36 and 0.5 m telescopes and low-light-level video cameras. The night side of the lunar surface provides a large collecting area for detecting these impacts and allows estimation of the flux of meteoroids down to a limiting luminous energy. In order to determine the limiting mass for these observations, models of the sporadic meteoroid environment were used to determine the velocity distribution and new measurements of luminous efficiency were made at the Ames Vertical Gun Range. The flux of meteoroids in this size range has implications for Near Earth Object populations as well as for estimating impact ejecta risk for future lunar missions.
Author
LUNAR SURFACE; METEOROID CONCENTRATION; EJECTA; METEOROIDS; NEAR EARTH OBJECTS; SPORADIC METEOROIDS; VELOCITY DISTRIBUTION; LUMINOSITY
20090019095 Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA, United States
Combinations of Earth Orientation Measurements: SPACE2007, COMB2007, and POLE2007
Ratcliff, J. T.; Gross, R. S.; April 2009; In English; Original contains black and white illustrations
Contract(s)/Grant(s): NAS7-03001Proj. 102688
Report No.(s): JPL-Publ-09-18; Copyright; Avail.: CASI: A03, Hardcopy
Independent Earth orientation measurements taken by the space-geodetic techniques of lunar and satellite laser ranging, very long baseline interferometry, and the Global Positioning System have been combined using a Kalman filter. The resulting combined Earth orientation series, SPACE2007, consists of values and uncertainties for Universal Time, polar motion, and their rates that span from September 28, 1976, to March 29, 2008, at daily intervals and is available in versions whose epochs are given at either midnight or noon. The space-geodetic measurements used to generate SPACE2007 have then been combined with optical astrometric measurements to form two additional combined Earth orientation series: (1) COMB2007, consisting of values and uncertainties for Universal Time, polar motion, and their rates that span from January 20, 1962, to March 29, 2008, at daily intervals and which is also available in versions whose epochs are given at either midnight or noon; and (2) POLE2007, consisting of values and uncertainties for polar motion and its rate that span from January 20, 1900, to March 22, 2008, at 30,4375-day intervals.
Author
EARTH ORIENTATION; GEODESY; DATA ACQUISITION; DATA INTEGRATION; UNIVERSAL TIME; POLAR WANDERING (GEOLOGY)
20090019098 NASA Marshall Space Flight Center, Huntsville, AL, United States
Activity Cycles in Stars
Hathaway, David H.; January 06, 2009; In English; European AstroFest 2009, 6-7 Jan. 2009, London, United Kingdom
Report No.(s): M09-0257; No Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090019098
Starspots and stellar activity can be detected in other stars using high precision photometric and spectrometric measurements. These observations have provided some surprises (starspots at the poles - sunspots are rarely seen poleward of 40 degrees) but more importantly they reveal behaviors that constrain our models of solar-stellar magnetic dynamos. The observations reveal variations in cycle characteristics that depend upon the stellar structure, convection zone dynamics, and rotation rate. In general, the more rapidly rotating stars are more active. However, for stars like the Sun, some are found to be inactive while nearly identical stars are found to be very active indicating that periods like the Sun's Maunder Minimum (an inactive period from 1645 to 1715) are characteristic of Sun-like stars.
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STELLAR ACTIVITY; ASTRONOMICAL SPECTROSCOPY; ASTRONOMICAL PHOTOMETRY
20090019101 NASA Marshall Space Flight Center, Huntsville, AL, United States
NASA's Student Launch Projects: A Government Education Program for Science and Engineering
Shepherd, Christena C.; [2009]; In English; Original contains color illustrations
Report No.(s): M09-0304; No Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090019101
Among the many NASA education activities, the Student Launch projects are examples of how one agency has been working with students to inspire math, science and engineering interest. There are two Student Launch projects: Student Launch Initiative (SLI) for middle and high school students and the University Student Launch Initiative (USLI) for college students. The programs are described and website links are provided for further information. This document presents an example of how an agency can work with its unique resources in partnership with schools and communities to bring excitement to the classroom.
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NASA PROGRAMS; EDUCATION; SCIENCE; ENGINEERING; STUDENTS
20090019110 NASA Glenn Research Center, Cleveland, OH, United States
Development of a Reactor Model for Chemical Conversion of Lunar Regolith
Hegde, U.; Balasubramaniam, R.; Gokoglu, S.; April 2009; In English; Space Technology and Applications International Forum (STAIF-2007), 11-14 Feb. 2007, Albuquerque, NM, United States; Original contains black and white illustrations
Contract(s)/Grant(s): NCC3-973WBS 387498.04.01.05.01.03
Report No.(s): NASA/TM-2009-215626; E-15954-1; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090019110
Lunar regolith will be used for a variety of purposes such as oxygen and propellant production and manufacture of various materials. The design and development of chemical conversion reactors for processing lunar regolith will require an understanding of the coupling among the chemical, mass and energy transport processes occurring at the length and time scales of the overall reactor with those occurring at the corresponding scales of the regolith particles. To this end, a coupled transport model is developed using, as an example, the reduction of ilmenite-containing regolith by a continuous flow of hydrogen in a flow-through reactor. The ilmenite conversion occurs on the surface and within the regolith particles. As the ilmenite reduction proceeds, the hydrogen in the reactor is consumed, and this, in turn, affects the conversion rate of the ilmenite in the particles. Several important quantities are identified as a result of the analysis. Reactor scale parameters include the void fraction (i.e., the fraction of the reactor volume not occupied by the regolith particles) and the residence time of hydrogen in the reactor. Particle scale quantities include the time for hydrogen to diffuse into the pores of the regolith particles and the chemical reaction time. The paper investigates the relationships between these quantities and their impact on the regolith conversion. Application of the model to various chemical reactor types, such as fluidized-bed, packed-bed, and rotary-bed configurations, are discussed.
Author
CHEMICAL REACTORS; ILMENITE; LUNAR ROCKS; REGOLITH; MODELS; MOON
20090019112 NASA Glenn Research Center, Cleveland, OH, United States
Intermetallic Nickel-Titanium Alloys for Oil-Lubricated Bearing Applications
DellaCorte, C.; Pepper, S. V.; Noebe, R.; Hull, D. R.; Glennon, G.; March 2009; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 877868.02.07.03.01.01.03
Report No.(s): NASA/TM-2009-215646; E-16957; Copyright; Avail.: CASI: A03, Hardcopy
An intermetallic nickel-titanium alloy, NITINOL 60 (60NiTi), containing 60 wt% nickel and 40 wt% titanium, is shown to be a promising candidate material for oil-lubricated rolling and sliding contact applications such as bearings and gears. NiTi alloys are well known and normally exploited for their shape memory behavior. When properly processed, however, NITINOL 60 exhibits excellent dimensional stability and useful structural properties. Processed via high temperature, high-pressure powder metallurgy techniques or other means, NITINOL 60 offers a broad combination of physical properties that make it unique among bearing materials. NITINOL 60 is hard, electrically conductive, highly corrosion resistant, less dense than steel, readily machined prior to final heat treatment, nongalling and nonmagnetic. No other bearing alloy, metallic or ceramic encompasses all of these attributes. Further, NITINOL 60 has shown remarkable tribological performance when compared to other aerospace bearing alloys under oil-lubricated conditions. Spiral orbit tribometer (SOT) tests were conducted in vacuum using NITINOL 60 balls loaded between rotating 440C stainless steel disks, lubricated with synthetic hydrocarbon oil. Under conditions considered representative of precision bearings, the performance (life and friction) equaled or exceeded that observed with silicon nitride or titanium carbide coated 440C bearing balls. Based upon this preliminary data, it appears that NITINOL 60, despite its high titanium content, is a promising candidate alloy for advanced mechanical systems requiring superior and intrinsic corrosion resistance, electrical conductivity and nonmagnetic behavior under lubricated contacting conditions.
Author
BALL BEARINGS; INTERMETALLICS; NITINOL ALLOYS; TRIBOLOGY; LUBRICATION; GEARS
20090019114 NASA Langley Research Center, Hampton, VA, United States
Mars Exploration Rover Flight Operations Technical Consultation
Leckrone, Dave S.; Null, Cynthia H.; Caldwell, John; Graves, Claude; Konitinos, Dean A.; April 2009; In English
Contract(s)/Grant(s): WBS 869021.06.07.05.99
Report No.(s): NASA/TM-2009-215713; NESC-RP-04-10/03-004-E; L-19652; LF99-8660; No Copyright; Avail.: CASI: A04, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090019114
The Mars Exploration Rover (MER) Project at the Jet Propulsion Laboratory developed two golf-cart size robotic vehicles, Spirit and Opportunity, for geological exploration of designated target areas on the surface of Mars. The primary scientific objective of these missions was the search for evidence of the presence of water on or near the surface of the planet during its history. Spirit and Opportunity were launched on June 10 and July 7, 2003, with their respective landings scheduled for January 4 and January 25, 2004 (UTC). NASA views the MER missions as particularly critical because of their scientific importance in the ongoing search for conditions under which life might have existed elsewhere in the solar system, because of their high level of public interest and because more than half of all prior missions launched to Mars internationally have failed. This report summarizes the findings and recommendations of the NASA Engineering and Safety Center review of the project.
Author
MARS MISSIONS; NASA PROGRAMS; MARS ROVING VEHICLES
20090019118 NASA Marshall Space Flight Center, Huntsville, AL, United States; NASA Marshall Space Flight Center, Huntsville, AL, United States
Role of Hf on Phase Formation in Ti45Zr(38-x)Hf(x)Ni17 Liquids and Solids
Wessels, V.; Sahu, K. K.; Gangopadhyay, A. K.; Huett, V. T.; Canepari, S.; Goldman, A. I.; Hyers, R. W.; Kramer, M. J.; Rogers, J. R.; Kelton, K. F.; Robinson, D.; December 2008; In English; Materials Research Society 2008 Fall Meeting, 1-5 Dec. 2008, Boston, MA, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): NNX074K27G; NSF-DMR-030410
Report No.(s): M09-0196; Copyright; Avail.: CASI: A01, Hardcopy
Hafnium and zirconium are very similar, with almost identical sizes and chemical bonding characteristics. However, they behave differently when alloyed with Ti and Ni. A sharp phase formation boundary near 18-21 at.% Hf is observed in rapidly-quenched and as-cast Ti45Zr38-xHfxNi17 alloys. Rapidly-quenched samples that contain less than 18 at.% Hf form the icosahedral quasicrystal phase, whiles samples containing more than 21 at.% form the 3/2 rational approximant phase. In cast alloys, a C14 structure is observed for alloys with Hf lower than the boundary concentration, while a large-cell (11.93 ) FCC Ti2Ni-type structure is found in alloys with Hf concentrations above the boundary. To better understand the role of Hf on phase formation, the structural evolution with supercooling and the solidification behavior of liquid Ti45Zr38-xHfxNi17 alloys (x=0, 12, 18, 21, 38) were studied using the Beamline Electrostatic Levitation (BESL) technique using 125keV x-rays on the 6ID-D beamline at the Advanced Photon Source, Argonne National Laboratory. For all liquids primary crystallization was to a BCC solid solution phase; interestly, an increase in Hf concentration leads to a decrease in the BCC lattice parameter in spite of the chemical similarity between Zr and Hf. A Reitveld analysis confirmed that as in the cast alloys, the secondary phase that formed was the C14 below the phase formation boundary and a Ti2Ni-type structure at higher Hf concentrations. Both the liquidus temperature and the reduced undercooling change sharply on traversing the phase formation boundary concentration, suggesting a change in the liquid structure. Structural information from a Honeycutt-Anderson index analysis of reverse Monte Carlo fits to the S(q) liquid data will be presented to address this issue.
Author
HAFNIUM; TITANIUM ALLOYS; ZIRCONIUM FLUORIDES
20090019128 NASA Ames Research Center, Moffett Field, CA, United States
Modeling Ablation of Fibrous Materials from Bulk to Knudsen Regime
Lachaud, Jean; Mansour, Nagi N.; August 17, 2008; In English; 19th International Symposium on Transport Phenomena, 17-20 Aug. 2008, Reykjavik, Iceland; Original contains color and black and white illustrations
Report No.(s): ARC-E-DAA-TN123; Copyright; Avail.: CASI: A02, Hardcopy
Material-environment interactions are analyzed at microscopic scale to explain the lower than expected density observed by post-flight analysis of the char layer on the Stardust shield. Mass transfer, ablation (oxidation), and surface recession of fibrous material is simulated in 3D using a Monte-Carlo simulation tool. Ablation is found to occur either at the surface or in volume depending on Knudsen and Thiele number values. This study supports the idea of volume ablation followed by possible carbon fiber spallation that may explain post-flight analyses.
Author
ABLATIVE MATERIALS; CARBON FIBERS; KNUDSEN FLOW; SPALLATION; POSTFLIGHT ANALYSIS; OXIDATION; FIBERS
20090019132 NASA Glenn Research Center, Cleveland, OH, United States
Variable/Multispeed Rotorcraft Drive System Concepts
Stevens, Mark A.; Handschuh, Robert F.; Lewicki, David G.; March 2009; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 877868.02.07.03.03.10.1
Report No.(s): NASA/TM-2009-215456; ARL-TR-4758; E-16649; Copyright; Avail.: CASI: A03, Hardcopy
Several recent studies for advanced rotorcraft have identified the need for variable, or multispeed-capable rotors. A speed change of up to 50 percent has been proposed for future rotorcraft to improve vehicle performance. Varying rotor speed during flight not only requires a rotor capable of performing effectively over the extended operation speed and load range, but also requires an advanced propulsion system to provide the required speed changes. A study has been completed, which investigated possible drive system arrangements to accommodate up to the 50 percent speed change. These concepts are presented. The most promising configurations are identified and will be developed for future validation testing.
Author
ROTARY WING AIRCRAFT; ROTORS; ROTOR SPEED; MECHANICAL DRIVES; PROPULSION SYSTEM PERFORMANCE
20090019133 NASA Langley Research Center, Hampton, VA, United States
Flight Deck Display Technologies for 4DT and Surface Equivalent Visual Operations
Prinzel, Lawrence J., III; Jones, Denis R.; Shelton, Kevin J.; Arthur, Jarvis J., III; Bailey, Randall E.; Allamandola, Angela S.; Foyle, David C.; Hooey, Becky L.; April 27, 2009; In English; 15th International Symposium on Aviation Psychology, 27-30 Apr. 2009, Dayton, OH, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 609866.02.07.07.02
Report No.(s): LF99-8434; Copyright; Avail.: CASI: A02, Hardcopy
NASA research is focused on flight deck display technologies that may significantly enhance situation awareness, enable new operating concepts, and reduce the potential for incidents/accidents for terminal area and surface operations. The display technologies include surface map, head-up, and head-worn displays; 4DT guidance algorithms; synthetic and enhanced vision technologies; and terminal maneuvering area traffic conflict detection and alerting systems. This work is critical to ensure that the flight deck interface technologies and the role of the human participants can support the full realization of the Next Generation Air Transportation System (NextGen) and its novel operating concepts.
Author
DISPLAY DEVICES; ENHANCED VISION; COCKPITS; PILOT SUPPORT SYSTEMS; TECHNOLOGY ASSESSMENT; HUMAN-COMPUTER INTERFACE; HUMAN FACTORS ENGINEERING; AIRCRAFT INSTRUMENTS; AIRCRAFT SAFETY; AVIONICS
20090019135 NASA Johnson Space Center, Houston, TX, United States
Shallow-Water Nitrox Diving, the NASA Experience
Fitzpatrick, Daniel T.; [2009]; In English; Undersea and Hyperbaric Medicine Society Annual Meeting, 25 - 27 Jun. 2009, Nevada, United States; Original contains color illustrations
Report No.(s): JSC-CN-18262; Copyright; Avail.: CASI: A01, Hardcopy
NASA s Neutral Buoyancy Laboratory (NBL) contains a 6.2 million gallon, 12-meter deep pool where astronauts prepare for space missions involving space walks (extravehicular activity EVA). Training is conducted in a space suit (extravehicular mobility unit EMU) pressurized to 4.0 - 4.3 PSI for up to 6.5 hours while breathing a 46% NITROX mix. Since the facility opened in 1997, over 30,000 hours of suited training has been completed with no occurrence of decompression sickness (DCS) or oxygen toxicity. This study examines the last 5 years of astronaut suited training runs. All suited runs are computer monitored and data is recorded in the Environmental Control System (ECS) database. Astronaut training runs from 2004 - 2008 were reviewed and specific data including total run time, maximum depth and average depth were analyzed. One hundred twenty seven astronauts and cosmonauts completed 2,231 training runs totaling 12,880 exposure hours. Data was available for 96% of the runs. It was revealed that the suit configuration produces a maximum equivalent air depth of 7 meters, essentially eliminating the risk of DCS. Based on average run depth and time, approximately 17% of the training runs exceeded the NOAA oxygen maximum single exposure limits, with no resulting oxygen toxicity. The NBL suited training protocols are safe and time tested. Consideration should be given to reevaluate the NOAA oxygen exposure limits for PO2 levels at or below 1 ATA.
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ASTRONAUT TRAINING; DIVING (UNDERWATER); NITROGEN; OXYGEN; DECOMPRESSION SICKNESS; HYPEROXIA; RISK MANAGEMENT; BIOASTRONAUTICS; EXTRAVEHICULAR ACTIVITY; SPACE SUITS; SPACE MISSIONS
20090019136 NASA Dryden Flight Research Center, Edwards, CA, United States
Updating the Finite Element Model of the Aerostructures Test Wing using Ground Vibration Test Data
Lung, Shun-fat; Pak, Chan-gi; May 04, 2009; In English; 50th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 4-7 May 2009, Palm Springs, CA, United States; Original contains color and black and white illustrations
Report No.(s): AIAA Paper 2009-2528; DFRC-856; DFRC-985; Copyright; Avail.: CASI: A03, Hardcopy
Improved and/or accelerated decision making is a crucial step during flutter certification processes. Unfortunately, most finite element structural dynamics models have uncertainties associated with model validity. Tuning the finite element model using measured data to minimize the model uncertainties is a challenging task in the area of structural dynamics. The model tuning process requires not only satisfactory correlations between analytical and experimental results, but also the retention of the mass and stiffness properties of the structures. Minimizing the difference between analytical and experimental results is a type of optimization problem. By utilizing the multidisciplinary design, analysis, and optimization (MDAO) tool in order to optimize the objective function and constraints; the mass properties, the natural frequencies, and the mode shapes can be matched to the target data to retain the mass matrix orthogonality. This approach has been applied to minimize the model uncertainties for the structural dynamics model of the Aerostructures Test Wing (ATW), which was designed and tested at the National Aeronautics and Space Administration (NASA) Dryden Flight Research Center (DFRC) (Edwards, California). This study has shown that natural frequencies and corresponding mode shapes from the updated finite element model have excellent agreement with corresponding measured data.
Author
DESIGN ANALYSIS; FINITE ELEMENT METHOD; MATHEMATICAL MODELS; VIBRATION TESTS; WINGS; FLUTTER ANALYSIS; STRUCTURAL DESIGN
20090019137 NASA Ames Research Center, Moffett Field, CA, United States
Automated Assume-Guarantee Reasoning by Abstraction Refinement
Pasareanu, Corina S.; Giannakopoulous, Dimitra; Glannakopoulou, Dimitra; July 07, 2008; In English; 20th International Conference on Computer Aided Verification (CAV) 2008, 7-14 Jul. 2008, Princeton, NJ, United States; Original contains black and white illustrations
Report No.(s): ARC-E-DAA-TN138; Copyright; Avail.: CASI: A03, Hardcopy
Current automated approaches for compositional model checking in the assume-guarantee style are based on learning of assumptions as deterministic automata. We propose an alternative approach based on abstraction refinement. Our new method computes the assumptions for the assume-guarantee rules as conservative and not necessarily deterministic abstractions of some of the components, and refines those abstractions using counter-examples obtained from model checking them together with the other components. Our approach also exploits the alphabets of the interfaces between components and performs iterative refinement of those alphabets as well as of the abstractions. We show experimentally that our preliminary implementation of the proposed alternative achieves similar or better performance than a previous learning-based implementation.
Author
AUTOMATA THEORY; MACHINE LEARNING; PROVING; ALGORITHMS
20090019139 NASA Langley Research Center, Hampton, VA, United States; Army Research Lab., United States
Application of Air Coupled Acoustic Thermography (ACAT) for Inspection of Honeycomb Sandwich Structures
Winfree, William P.; Zalameda, Joseph N.; Pergantis, Charles; Flanagan, David; Deschepper, Daniel; April 13, 2009; In English; SPIE Defense, Security, and Sensing 2009, 13 - 17 Apr. 2009, Florida, United States; Original contains color and black and white illustrations
Report No.(s): LF99-7784; Copyright; Avail.: CASI: A02, Hardcopy
The application of a noncontact air coupled acoustic heating technique is investigated for the inspection of advanced honeycomb composite structures. A weakness in the out of plane stiffness of the structure, caused by a delamination or core damage, allows for the coupling of acoustic energy and thus this area will have a higher temperature than the surrounding area. Air coupled acoustic thermography (ACAT) measurements were made on composite sandwich structures with damage and were compared to conventional flash thermography. A vibrating plate model is presented to predict the optimal acoustic source frequency. Improvements to the measurement technique are also discussed.
Author
ACOUSTIC COUPLING; THERMOGRAPHY; SANDWICH STRUCTURES; HONEYCOMB STRUCTURES; INSPECTION; COMPOSITE STRUCTURES; ACOUSTIC MEASUREMENT; SOUND WAVES
20090019145 BAE Systems, Huntsville, AL, United States; NASA Marshall Space Flight Center, Huntsville, AL, United States
Lunar Regolith Characterization for Simulant Design and Evaluation
Schrader, Christian M.; Stoeser, Douglas; Rickman, Douglas; Wentworth, Susan J.; Mclemore, Carole; Fikes, John; McKay, David S.; January 05, 2009; In English; 47th AIAA Aerospace Sciences Meeting, 5-8 Jan. 2009, Orlando, FL, United States
Report No.(s): MSFC-2194; Copyright; Avail.: CASI: A01, Hardcopy
NASA's Marshall Space Flight Center (MSFC), in conjunction with the United States Geological Survey (USGS), is implementing a new data acquisition strategy to support the development and evaluation of lunar regolith simulants. The objective is to characterize the variance in particle composition, size, shape, and bulk density of the lunar regolith. Apollo drive and drill cores are the preferred samples as they allow for investigation of variation with depth, and many proposed operations on the moon will involve excavation of lunar regolith to depths of at least tens of centimeters. Multiple Apollo cores will be sampled multiple times along their vertical axes and analyzed. This will permit statistical statements about variation both within a core, between closely spaced cores, and between distant areas.
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CHARACTERIZATION; MOON; REGOLITH; LUNAR RESOURCES; SELENOLOGY; LUNAR ROCKS; LUNAR GEOLOGY
20090019146 Princeton Univ., NJ, United States
Binodal Colloidal Aggregation Test - 4: Polydispersion
Chaikin, Paul M.; September 23, 2008; In English; Original contains color illustrations
Report No.(s): JSC-CN-17962-3; Copyright; Avail.: CASI: A01, Hardcopy
Binodal Colloidal Aggregation Test - 4: Polydispersion (BCAT-4-Poly) will use model hard-spheres to explore seeded colloidal crystal nucleation and the effects of polydispersity, providing insight into how nature brings order out of disorder. Crewmembers photograph samples of polymer and colloidal particles (tiny nanoscale spheres suspended in liquid) that model liquid/gas phase changes. Results will help scientists develop fundamental physics concepts previously cloaked by the effects of gravity.
Author
GRAVITATIONAL EFFECTS; SPHERES; CRYSTALS; COLLOIDS; NUCLEATION
Additions to the NASA Aeronautics and Space Database as of 05/29/2009
20090019561 NASA Marshall Space Flight Center, Huntsville, AL, United States
Solar Sailing
Johnson, Les; February 02, 2009; In English; Space, Propulsion and Energy Sciences International Forum 2009, 24 - 26 Feb. 2009, Alabama, United States
Report No.(s): M09-0321; M09-0314; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090019561
Solar sailing is a topic of growing technical and popular interest. Solar sail propulsion will make space exploration more affordable and offer access to destinations within (and beyond) the solar system that are currently beyond our technical reach. The lecture will describe solar sails, how they work, and what they will be used for in the exploration of space. It will include a discussion of current plans for solar sails and how advanced technology, such as nanotechnology, might enhance their performance. Much has been accomplished recently to make solar sail technology very close to becoming an engineering reality and it will soon be used by the world s space agencies in the exploration of the solar system and beyond. The first part of the lecture will summarize state-of-the-art space propulsion systems and technologies. Though these other technologies are the key to any deep space exploration by humans, robots, or both, solar-sail propulsion will make space exploration more affordable and offer access to distant and difficult destinations. The second part of the lecture will describe the fundamentals of space solar sail propulsion and will describe the near-, mid- and far-term missions that might use solar sails as a propulsion system. The third part of the lecture will describe solar sail technology and the construction of current and future sailcraft, including the work of both government and private space organizations.
Author
PROPULSION SYSTEM CONFIGURATIONS; PROPULSION SYSTEM PERFORMANCE; SOLAR SAILS; SPACECRAFT PROPULSION; PROPULSIVE EFFICIENCY
20090019565 NASA Dryden Flight Research Center, Edwards, CA, United States
Inter-agency Working Group for Airborne Data and Telemetry Systems (IWGADTS)
Webster, Chris; Freudinge, Lawrence; Sorenson, Carl; Myers, Jeff; Sullivan, Don; Oolman, Larry; May 04, 2009; In English; 33rd International Symposium on Remote Sensing of Environment, 4 - 8 May 2009, Stresa, Italy; Original contains color illustrations
Report No.(s): Paper-PS-C3-13/294; DFRC-996; Copyright; Avail.: CASI: A01, Hardcopy
The Interagency Coordinating Committee for Airborne Geosciences Research and Applications (ICCAGRA) was established to improve cooperation and communication among agencies sponsoring airborne platforms and instruments for research and applications, and to serve as a resource for senior level management on airborne geosciences issues. The Interagency Working Group for Airborne Data and Telecommunications Systems (IWGADTS) is a subgroup to ICCAGRA for the purpose of developing recommendations leading to increased interoperability among airborne platforms and instrument payloads, producing increased synergy among research programs with similar goals, and enabling the suborbital layer of the Global Earth Observing System of Systems.
Author
AIRBORNE EQUIPMENT; EARTH OBSERVING SYSTEM (EOS); PAYLOADS; RESOURCES MANAGEMENT; TELECOMMUNICATION; GEOPHYSICS; FLYING PLATFORMS; GEOLOGY
20090019566 NASA Johnson Space Center, Houston, TX, United States
Space Adaptation Back Pain: A Retrospective Study
Kerstman, Eric; May 03, 2009; In English; Aerospace Medical Association (AsMA) 80th Annual Meeting, 3 - 7 May 2009, California, United States; Original contains color illustrations
Report No.(s): JSC-CN-18241; Copyright; Avail.: CASI: A03, Hardcopy
Astronaut back pain is frequently reported in the early phase of space flight as they adapt to microgravity. The epidemiology of space adaptation back pain (SABP) has not been well established. This presentation seeks to determine the exact incidence of SABP among astronauts, develop a case definition of SABP, delineate the nature and pattern of SABP, review available treatments and their effectiveness in relieving SABP; and identify any operational impact of SABP. A retrospective review of all available mission medical records of astronauts in the U.S. space program was performed. It was revealed that the incidence of SABP has been determined to be 53% among astronauts in the U.S. space program; most cases of SABP are mild, self-limited, or respond to available treatment; there are no currently accepted preventive measures for SABP; it is difficult to predict who will develop SABP; the precise mechanism and spinal structures responsible for SABP are uncertain; there was no documented evidence of direction operational mission impact related to SABP; and, that there was the potential for mission impact related to uncontrolled pain, sleep disturbance, or the adverse side effects pf anti-inflammatory medications
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SPACE ADAPTATION SYNDROME; BIOASTRONAUTICS; AEROSPACE MEDICINE; MANNED SPACE FLIGHT; PHYSIOLOGICAL EFFECTS; BACK INJURIES; PAIN; GRAVITATIONAL PHYSIOLOGY; BIODYNAMICS; SPACE FLIGHT STRESS
20090019567 NASA Johnson Space Center, Houston, TX, United States
Heart Rhythm Monitoring in the Constellation Lunar and Launch/Landing EVA Suit: Recommendations from an Expert Panel
Scheuring, Richard A.; Hamilton, Doug; Jones, Jeffrey A.; Alexander, David; May 03, 2009; In English; Aerospace Medical Association (AsMA) 80th Annual Meeting, 3 - 7 May 2009, California, United States; Original contains color illustrations
Report No.(s): JSC-CN-18264; Copyright; Avail.: CASI: A03, Hardcopy
There are currently several physiological monitoring requirements for EVA in the Human-Systems Interface Requirements (HSIR) document. There are questions as to whether the capability to monitor heart rhythm in the lunar surface space suit is a necessary capability for lunar surface operations. Similarly, there are questions as to whether the capability to monitor heart rhythm during a cabin depressurization scenario in the launch/landing space suit is necessary. This presentation seeks to inform space medicine personnel of recommendations made by an expert panel of cardiovascular medicine specialists regarding in-suit ECG heart rhythm monitoring requirements during lunar surface operations. After a review of demographic information and clinical cases and panel discussion, the panel recommended that ECG monitoring capability as a clinical tool was not essential in the lunar space suit; ECG monitoring was not essential in the launch/landing space suit for contingency scenarios; the current hear rate monitoring capability requirement for both launch/landing and lunar space suits should be maintained; lunar vehicles should be required to have ECG monitoring capability with a minimum of 5-lead ECG for IVA medical assessments; and, exercise stress testing for astronaut selection and retention should be changed from the current 85% maximum heart rate limit to maximal, exhaustive 'symptom-limited' testing to maximize diagnostic utility as a screening tool for evaluating the functional capacity of astronauts and their cardiovascular health.
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AEROSPACE MEDICINE; HEART RATE; ELECTROCARDIOGRAPHY; EXTRAVEHICULAR ACTIVITY; SPACE SUITS; ASTRONAUTS; HEALTH; MICROGRAVITY; PHYSIOLOGICAL RESPONSES; GRAVITATIONAL PHYSIOLOGY; BIOASTRONAUTICS
Additions to the NASA Aeronautics and Space Database as of 06/01/2009
20090019649 NASA Johnson Space Center, Houston, TX, United States
Isokinetic Strength and Endurance Tests used Pre- and Post-Spaceflight: Test-Retest Reliability
Laughlin, Mitzi S.; Lee, Stuart M. C.; Loehr, James A.; Amonette, William E.; [2009]; In English; Original contains black and white illustrations
Report No.(s): JSC-CN-18042; Copyright; Avail.: CASI: A03, Hardcopy
To assess changes in muscular strength and endurance after microgravity exposure, NASA measures isokinetic strength and endurance across multiple sessions before and after long-duration space flight. Accurate interpretation of pre- and post-flight measures depends upon the reliability of each measure. The purpose of this study was to evaluate the test-retest reliability of the NASA International Space Station (ISS) isokinetic protocol. Twenty-four healthy subjects (12 M/12 F, 32.0 +/- 5.6 years) volunteered to participate. Isokinetic knee, ankle, and trunk flexion and extension strength as well as endurance of the knee flexors and extensors were measured using a Cybex NORM isokinetic dynamometer. The first weekly session was considered a familiarization session. Data were collected and analyzed for weeks 2-4. Repeated measures analysis of variance (alpha=0.05) was used to identify weekly differences in isokinetic measures. Test-retest reliability was evaluated by intraclass correlation coefficients (ICC) (3,1). No significant differences were found between weeks in any of the strength measures and the reliability of the strength measures were all considered excellent (ICC greater than 0.9), except for concentric ankle dorsi-flexion (ICC=0.67). Although a significant difference was noted in weekly endurance measures of knee extension (p less than 0.01), the reliability of endurance measure by week were considered excellent for knee flexion (ICC=0.97) and knee extension (ICC=0.96). Except for concentric ankle dorsi-flexion, the isokinetic strength and endurance measures are highly reliable when following the NASA ISS protocol. This protocol should allow accurate interpretation isokinetic data even with a small number of crew members.
Author
MICROGRAVITY; LONG DURATION SPACE FLIGHT; ASTRONAUTS; BIOASTRONAUTICS; GRAVITATIONAL PHYSIOLOGY; GRAVITATIONAL EFFECTS; PHYSIOLOGICAL EFFECTS; MUSCULAR STRENGTH; PHYSICAL FITNESS; PHYSICAL EXAMINATIONS; RELIABILITY
20090019650 NASA Johnson Space Center, Houston, TX, United States
OTF Mission Operations Prototype Status
Reynolds, Walter f.; Lucord, Steven A.; Stevens, John E.; April 20, 2009; In English; CCSDS Spring 2009 Technical Meeting, 20-25 Apr. 2009, Colorado Springs, CO, United States; Original contains color illustrations
Report No.(s): JSC-CN-17963; No Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090019650
A prototype system for monitoring spacecraft operations and control, including an alert system, is highlighted.
CASI
SPACECRAFT PERFORMANCE; OPERATIONAL PROBLEMS; WARNING SYSTEMS; SYSTEMS HEALTH MONITORING; PROTOTYPES; AEROSPACE SAFETY
20090019654 NASA Marshall Space Flight Center, Huntsville, AL, United States
Satellite Proving Ground for the GOES-R Geostationary Lightning Mapper (GLM)
Goodman, Steven J.; Gurka, James; Bruning, E. C.; Blakeslee, J. R.; Rabin, Robert; Buechler, D.; January 13, 2009; In English; 2009 MMS Annual Meeting/American Meteorological Society, 11-15 Jan. 2009, Phoenix, Az, United States; Original contains color illustrations
Report No.(s): M09-0282; Copyright; Avail.: CASI: A03, Hardcopy
The key mission of the Satellite Proving Ground is to demonstrate new satellite observing data, products and capabilities in the operational environment to be ready on Day 1 to use the GOES-R suite of measurements. Algorithms, tools, and techniques must be tested, validated, and assessed by end users for their utility before they are finalized and incorporated into forecast operations. The GOES-R Proving Ground for the Geostationary Lightning Mapper (GLM) focuses on evaluating how the infusion of the new technology, algorithms, decision aids, or tailored products integrate with other available tools (weather radar and ground strike networks; nowcasting systems, mesoscale analysis, and numerical weather prediction models) in the hands of the forecaster responsible for issuing forecasts and warning products. Additionally, the testing concept fosters operation and development staff interactions which will improve training materials and support documentation development. Real-time proxy total lightning data from regional VHF lightning mapping arrays (LMA) in Northern Alabama, Central Oklahoma, Cape Canaveral Florida, and the Washington, DC Greater Metropolitan Area are the cornerstone for the GLM Proving Ground. The proxy data will simulate the 8 km Event, Group and Flash data that will be generated by GLM. Tailored products such as total flash density at 1-2 minute intervals will be provided for display in AWIPS-2 to select NWS forecast offices and national centers such as the Storm Prediction Center. Additional temporal / spatial combinations are being investigated in coordination with operational needs and case-study proxy data and prototype visualizations may also be generated from the NASA heritage Lightning Imaging Sensor and Optical Transient Detector data. End users will provide feedback on the utility of products in their operational environment, identify use cases and spatial/temporal scales of interest, and provide feedback to the developers for adjusted or new products.
Author
GOES SATELLITES; LIGHTNING; MAPPING; SYSTEMS ANALYSIS; RADAR NETWORKS; MESOMETEOROLOGY; MESOSCALE PHENOMENA; IMAGING TECHNIQUES; NUMERICAL WEATHER FORECASTING
20090019660 NASA Dryden Flight Research Center, Edwards, CA, United States
NASA Dryden Status
Bosworth, John T.; February 2009; In English; Aerospace Control and Guidance Systems Committee Meeting 103, 25-27 Feb. 2009, Seattle, WA, United States; Original contains color illustrations
Report No.(s): DFRC-957; No Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090019660
This slide presentation reviews the status of several NASA Dryden projects. These include: the Lift And Nozzle Change Effects on Tail Shock (LANCETS), Integrated Resilient Aircraft Control (IRAC) F-18 #853 Testbed X-48B, Blended Wing Body flights, Stratospheric Observatory for Infrared Astronomy (SOFIA), Ikhana Project, and the Orion Crew Exploration Vehicle (CEV) Launch Abort Systems Tests
CASI
NASA PROGRAMS; RESEARCH AIRCRAFT; PROGRESS; AIRCRAFT DESIGN; AIRCRAFT CONFIGURATIONS; AIRCRAFT CONTROL
20090019661 NASA Dryden Flight Research Center, Edwards, CA, United States
Open-Loop Pitch Table Optimization for the Maximum Dynamic Pressure Orion Abort Flight Test
Stilwater, Ryan A.; April 29, 2009; In English; Original contains color illustrations
Report No.(s): DFRC-983; DFRC-982; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090019661
NASA has scheduled the retirement of the space shuttle orbiter fleet at the end of 2010. The Constellation program was created to develop the next generation of human spaceflight vehicles and launch vehicles, known as Orion and Ares respectively. The Orion vehicle is a return to the capsule configuration that was used in the Mercury, Gemini, and Apollo programs. This configuration allows for the inclusion of an abort system that safely removes the capsule from the booster in the event of a failure on launch. The Flight Test Office at NASA's Dryden Flight Research Center has been tasked with the flight testing of the abort system to ensure proper functionality and safety. The abort system will be tested in various scenarios to approximate the conditions encountered during an actual Orion launch. Every abort will have a closed-loop controller with an open-loop backup that will direct the vehicle during the abort. In order to provide the best fit for the desired total angle of attack profile with the open-loop pitch table, the table is tuned using simulated abort trajectories. A pitch table optimization program was created to tune the trajectories in an automated fashion. The program development was divided into three phases. Phase 1 used only the simulated nominal run to tune the open-loop pitch table. Phase 2 used the simulated nominal and three simulated off nominal runs to tune the open-loop pitch table. Phase 3 used the simulated nominal and sixteen simulated off nominal runs to tune the open-loop pitch table. The optimization program allowed for a quicker and more accurate fit to the desired profile as well as allowing for expanded resolution of the pitch table.
Author
CONSTELLATION PROGRAM; CREW EXPLORATION VEHICLE; LAUNCHING; FAILURE; ABORT APPARATUS; ABORT TRAJECTORIES; PITCH (INCLINATION); TRAJECTORY OPTIMIZATION; DYNAMIC PRESSURE; FLIGHT TESTS
20090019673 NASA Langley Research Center, Hampton, VA, United States
Design and Manufacturing of Tow-Steered Composite Shells Using Fiber Placement
Wu, K. Chauncey; Tatting, Brian F.; Smith, Brett H.; Stevens, Randy S.; Occhipiniti, Gina P.; Swift, Jonathan B.; Achary, David C.; Thornburgh, Robert P.; May 04, 2009; In English; 50th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 4-7 May 2009, Palm Springs, CA, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 561581.02.08.07.15.03
Report No.(s): AIAA Paper-2009-2700; LF99-7420; Copyright; Avail.: CASI: A03, Hardcopy
Advanced composite shells that may offer the potential to improve the structural performance of future aircraft fuselage structures were developed under this joint NASA-industry collaborative effort. Two cylindrical shells with tailored, tow-steered layups and continuously varying fiber angle orientations were designed and built at the National Center for Advanced Manufacturing - Louisiana Partnership. The shells were fabricated from unidirectional IM7/8552 graphite-epoxy pre-preg slit tape material fiber-placed on a constant-diameter mandrel. Each shell had the same nominal 8-ply [plus or minus 45/plus or minus Theta]s layup, where the nominal fiber angle in the tow-steered plies varied continuously from 10 degrees along the crown to 45 degrees on each side, then back to 10 degrees on the keel. One shell was fabricated with all 24 tows placed during each pass of the fiber placement machine, resulting in many tow overlaps on the shell surface. The fiber placement machine's individual tow cut/restart capability was also used to manufacture a second shell with tow drops and a more uniform laminate thickness. This paper presents an overview of the detailed design and manufacturing processes for these shells, and discusses issues encountered during their fabrication and post-cure evaluation. Future plans for structural testing and analyses of the shells are also discussed.
Author
COMPOSITE STRUCTURES; SHELLS (STRUCTURAL FORMS); CYLINDRICAL SHELLS; FIBER ORIENTATION; REINFORCING FIBERS; COMPOSITE MATERIALS; MECHANICAL PROPERTIES; DESIGN ANALYSIS; MANUFACTURING; FABRICATION
20090019674 National Inst. of Aerospace, Hampton, VA, United States; NASA Langley Research Center, Hampton, VA, United States
Prediction of Material Properties of Nanostructured Polymer Composites Using Atomistic Simulations
Hinkley, J.A.; Clancy, T.C.; Frankland, S.J.V.; May 04, 2009; In English; 50th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 4 - 7 May 2009, California, United States; Original contains color and black and white illustrations
Report No.(s): LF99-8544; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090019674
Atomistic models of epoxy polymers were built in order to assess the effect of structure at the nanometer scale on the resulting bulk properties such as elastic modulus and thermal conductivity. Atomistic models of both bulk polymer and carbon nanotube polymer composites were built. For the bulk models, the effect of moisture content and temperature on the resulting elastic constants was calculated. A relatively consistent decrease in modulus was seen with increasing temperature. The dependence of modulus on moisture content was less consistent. This behavior was seen for two different epoxy systems, one containing a difunctional epoxy molecule and the other a tetrafunctional epoxy molecule. Both epoxy structures were crosslinked with diamine curing agents. Multifunctional properties were calculated with the nanocomposite models. Molecular dynamics simulation was used to estimate the interfacial thermal (Kapitza) resistance between the carbon nanotube and the surrounding epoxy matrix. These estimated values were used in a multiscale model in order to predict the thermal conductivity of a nanocomposite as a function of the nanometer scaled molecular structure.
Author
EPOXY MATRIX COMPOSITES; THERMAL CONDUCTIVITY; ELASTIC PROPERTIES; MODULUS OF ELASTICITY; EPOXY RESINS; MOLECULAR DYNAMICS; NANOCOMPOSITES
20090019675 ILC Dover, Frederica, DE, United States; NASA Langley Research Center, Hampton, VA, United States
Modeling and Simulation of the Second-Generation Orion Crew Module Air Bag Landing System
Timmers, Richard B.; Welch, Joseph V.; Hardy, Robin C.; May 04, 2009; In English; 20th AIAA Aerodynamic Decelerator Systems Technology Conference, 4 - 7 May 2009, Washington, United States; Original contains color and black and white illustrations
Report No.(s): LF99-8546; Copyright; Avail.: CASI: A03, Hardcopy
Air bags were evaluated as the landing attenuation system for earth landing of the Orion Crew Module (CM). An important element of the air bag system design process is proper modeling of the proposed configuration to determine if the resulting performance meets requirements. Analysis conducted to date shows that airbags are capable of providing a graceful landing of the CM in nominal and off-nominal conditions such as parachute failure, high horizontal winds, and unfavorable vehicle/ground angle combinations. The efforts presented here surround a second generation of the airbag design developed by ILC Dover, and is based on previous design, analysis, and testing efforts. In order to fully evaluate the second generation air bag design and correlate the dynamic simulations, a series of drop tests were carried out at NASA Langley's Landing and Impact Research (LandIR) facility. The tests consisted of a full-scale set of air bags attached to a full-scale test article representing the Orion Crew Module. The techniques used to collect experimental data, construct the simulations, and make comparisons to experimental data are discussed.
Author
AIR BAG RESTRAINT DEVICES; SPACECRAFT LANDING; CREW EXPLORATION VEHICLE; SPACECRAFT MODULES; LANDING AIDS; SYSTEMS ENGINEERING; SPACECRAFT DESIGN; AEROSPACE ENGINEERING
20090019676 NASA Langley Research Center, Hampton, VA, United States; Engineering Mechanics Corp. of Columbus, Columbus, OH, United States
Residual Stresses and Critical Initial Flaw Size Analyses of Welds
Brust, Frederick W.; Raju, Ivatury, S.; Dawocke, David S.; Cheston, Derrick; May 04, 2009; In English; 50th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 4 - 7 May 2009, California, United States; Original contains black and white illustrations
Report No.(s): LF99-8550; Copyright; Avail.: CASI: A03, Hardcopy
An independent assessment was conducted to determine the critical initial flaw size (CIFS) for the flange-to-skin weld in the Ares I-X Upper Stage Simulator (USS). A series of weld analyses are performed to determine the residual stresses in a critical region of the USS. Weld residual stresses both increase constraint and mean stress thereby having an important effect on the fatigue life. The purpose of the weld analyses was to model the weld process using a variety of sequences to determine the 'best' sequence in terms of weld residual stresses and distortions. The many factors examined in this study include weld design (single-V, double-V groove), weld sequence, boundary conditions, and material properties, among others. The results of this weld analysis are included with service loads to perform a fatigue and critical initial flaw size evaluation.
Author
RESIDUAL STRESS; WELDED JOINTS; FATIGUE LIFE; LOADS (FORCES); ARES 1 UPPER STAGE; SEQUENCING; DISTORTION
20090019677 NASA Langley Research Center, Hampton, VA, United States; National Inst. of Aerospace, Hampton, VA, United States
The Effect of Water on the Work of Adhesion at Epoxy Interfaces by Molecular Dynamics Simulation
Hinkley, J.A.; Frankland, S.J.V.; Clancy, T.C.; May 04, 2009; In English; AIAA SDM Conference, 4 - 7 May 2009, California, United States; Original contains color and black and white illustrations
Report No.(s): LF99-8553; Copyright; Avail.: CASI: A02, Hardcopy
Molecular dynamics simulation can be used to explore the detailed effects of chemistry on properties of materials. In this paper, two different epoxies found in aerospace resins are modeled using molecular dynamics. The first material, an amine-cured tetrafunctional epoxy, represents a composite matrix resin, while the second represents a 177 C-cured adhesive. Surface energies are derived for both epoxies and the work of adhesion values calculated for the epoxy/epoxy interfaces agree with experiment. Adding water -- to simulate the effect of moisture exposure -- reduced the work of adhesion in one case, and increased it in the other. To explore the difference, the various energy terms that make up the net work of adhesion were compared and the location of the added water was examined.
Author
ADHESION; ADHESIVES; EPOXY RESINS; MOLECULAR DYNAMICS; SIMULATION; WATER; AEROSPACE ENGINEERING
20090019678 Analytical Services and Materials, Inc., Hampton, VA, United States
Fracture Test Methods for Plastically Responding COPV Liners
Dawicke, David S.; Lewis, Joseph C.; May 04, 2009; In English; 50th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 4 - 7 May 2009, California, United States; Original contains color and black and white illustrations
Report No.(s): AIAA Paper 2009-2516; LF99-8561; Copyright; Avail.: CASI: A02, Hardcopy
An experimental procedure for evaluating the validity of using uniaxial tests to provide a conservative bound on the fatigue crack growth rate behavior small cracks in bi-axially loaded Composite Overwrapped Pressure Vessel (COPV) liners is described. The experimental procedure included the use of a laser notch to quickly generate small surface fatigue cracks with the desired size and aspect ratios. An out-of-plane constraint system was designed to allow fully reversed, fully plastic testing of thin sheet uniaxial coupons. Finally, a method was developed to determine to initiate small cracks in the liner of COPVs.
Author
PRESSURE VESSELS; COMPOSITE WRAPPING; LININGS; PLASTIC PROPERTIES; FRACTURE MECHANICS; FATIGUE (MATERIALS); FATIGUE TESTS
20090019679 NASA Langley Research Center, Hampton, VA, United States; Airborne Systems North America, Santa Ana, CA, United States
A Summary of the Development of a Nominal Land Landing Airbag Impact Attenuation System for the Orion Crew Module
Tutt, Ben; Gill, Susannah; Wilson, Aaron; Johnson, Keith; May 04, 2009; In English; 20th AIAA Aerodynamic Decelerator Systems Technology Conference, 4 - 7 May 2009, Washington, United States; Original contains color and black and white illustrations
Report No.(s): LF99-8566; Copyright; Avail.: CASI: A03, Hardcopy
Airborne Systems North America (formally Irvin Aerospace Inc) has developed an Airbag Landing System for the Orion Crew Module of the Crew Exploration Vehicle. This work is in support of the NASA Langley Research Center Landing System Advanced Development Project. Orion is part of the Constellation Program to send human explorers back to the moon, and then onwards to Mars and other destinations in the Solar System. A component of the Vision for Space Exploration, Orion is being developed to also enable access to space following the retirement of the Space Shuttle in the next decade. This paper documents the development of a conceptual design, fabrication of prototype assemblies, component level testing and two generations of airbag landing system testing. The airbag system has been designed and analyzed using the transient dynamic finite element code LS-DYNA(RegisteredTradeMark). The landing system consists of six airbag assemblies; each assembly comprising a primary impact venting airbag and a non-venting anti-bottoming airbag. The anti-bottoming airbag provides ground clearance following the initial impact attenuation sequence. Incorporated into each primary impact airbag is an active vent that allows the entrapped gas to exit the control volume. The size of the vent is tailored to control the flow-rate of the exiting gas. An internal shaping structure is utilized to control the shape of the primary or main airbags prior to ground impact; this significantly improves stroke efficiency and performance.
Author
AIR BAG RESTRAINT DEVICES; CREW EXPLORATION VEHICLE; LANDING AIDS; SPACECRAFT MODULES; SYSTEMS ENGINEERING; SPACECRAFT DESIGN; AEROSPACE ENGINEERING
Additions to the NASA Aeronautics and Space Database as of 06/02/2009
20090019712 NASA Goddard Space Flight Center, Greenbelt, MD, United States
The Principle of Energetic Consistency: Application to the Shallow-Water Equations
Cohn, Stephen E.; [2009]; In English; Original contains black and white illustrations
No Copyright; Avail.: CASI: A04, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090019712
If the complete state of the earth's atmosphere (e.g., pressure, temperature, winds and humidity, everywhere throughout the atmosphere) were known at any particular initial time, then solving the equations that govern the dynamical behavior of the atmosphere would give the complete state at all subsequent times. Part of the difficulty of weather prediction is that the governing equations can only be solved approximately, which is what weather prediction models do. But weather forecasts would still be far from perfect even if the equations could be solved exactly, because the atmospheric state is not and cannot be known completely at any initial forecast time. Rather, the initial state for a weather forecast can only be estimated from incomplete observations taken near the initial time, through a process known as data assimilation. Weather prediction models carry out their computations on a grid of points covering the earth's atmosphere. The formulation of these models is guided by a mathematical convergence theory which guarantees that, given the exact initial state, the model solution approaches the exact solution of the governing equations as the computational grid is made more fine. For the data assimilation process, however, there does not yet exist a convergence theory. This book chapter represents an effort to begin establishing a convergence theory for data assimilation methods. The main result, which is called the principle of energetic consistency, provides a necessary condition that a convergent method must satisfy. Current methods violate this principle, as shown in earlier work of the author, and therefore are not convergent. The principle is illustrated by showing how to apply it as a simple test of convergence for proposed methods.
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WEATHER FORECASTING; DYNAMICAL SYSTEMS; MATHEMATICAL MODELS; EQUATIONS; PRINCIPLES; DATA INTEGRATION; ACCURACY
20090019713 NASA Goddard Space Flight Center, Greenbelt, MD, United States
Water Vapor Measurements by Howard University Raman Lidar during the WAVES 2006 Campaign
Adam, M.; Demoz, B. B.; Whiteman, D. N.; Venable, D. D.; Joseph E.; Gambacorta, A.; Wei, J.; Shephard, M. W.; Miloshevich, L. M.; Barnet, C. D.; Herman, R. L.; Fitzgibbon, J.; Connell, R.; [2009]; In English; Original contains color and black and white illustrations
Copyright; Avail.: CASI: A04, Hardcopy
Retrieval of water vapor mixing ratio using the Howard University Raman Lidar is presented with emphasis on three aspects: i) performance of the lidar against collocated radiosondes and Raman lidar, ii) investigation of the atmospheric state variables when poor agreement between lidar and radiosondes values occurred and iii) a comparison with satellite-based measurements. The measurements were acquired during the Water Vapor Validation Experiment Sondes/Satellites 2006 field campaign. Ensemble averaging of water vapor mixing ratio data from ten night-time comparisons with Vaisala RS92 radiosondes shows on average an agreement within 10 % up to approx. 8 km. A similar analysis of lidar-to-lidar data of over 700 profiles revealed an agreement to within 20 % over the first 7 km (10 % below 4 km). A grid analysis, defined in the temperature - relative humidity space, was developed to characterize the lidar - radiosonde agreement and quantitatively localizes regions of strong and weak correlations as a function of altitude, temperature or relative humidity. Three main regions of weak correlation emerge: i) regions of low relative humidity and low temperature, ii) moderate relative humidity at low temperatures and iii) low relative humidity at moderate temperatures. Comparison of Atmospheric InfraRed Sounder and Tropospheric Emission Sounder satellites retrievals of moisture with that of Howard University Raman Lidar showed a general agreement in the trend but the formers miss a lot of the details in atmospheric structure due to their low resolution. A relative difference of about 20 % is usually found between lidar and satellites measurements.
Author
WATER VAPOR; RADAR MEASUREMENT; INFRARED INSTRUMENTS; TEMPERATURE PROFILES; OPTICAL RADAR
20090019723 NASA Langley Research Center, Hampton, VA, United States
Evaluation of Fused Synthetic and Enhanced Vision Display Concepts for Low-Visibility Approach and Landing
Bailey, Randall E.; Kramer, Lynda J.; Prinzel, Lawrence J., III; Wilz, Susan J.; April 2009; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 609866.02.07.07.02
Report No.(s): NASA/TP-2009-215707; L-19504; LF99-7406; No Copyright; Avail.: CASI: A05, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090019723
NASA is developing revolutionary crew-vehicle interface technologies that strive to proactively overcome aircraft safety barriers that would otherwise constrain the full realization of the next generation air transportation system. A piloted simulation experiment was conducted to evaluate the complementary use of Synthetic and Enhanced Vision technologies. Specific focus was placed on new techniques for integration and/or fusion of Enhanced and Synthetic Vision and its impact within a two-crew flight deck during low-visibility approach and landing operations. Overall, the experimental data showed that significant improvements in situation awareness, without concomitant increases in workload and display clutter, could be provided by the integration and/or fusion of synthetic and enhanced vision technologies for the pilot-flying and the pilot-not-flying. Improvements in lateral path control performance were realized when the Head-Up Display concepts included a tunnel, independent of the imagery (enhanced vision or fusion of enhanced and synthetic vision) presented with it. During non-normal operations, the ability of the crew to handle substantial navigational errors and runway incursions were neither improved nor adversely impacted by the display concepts. The addition of Enhanced Vision may not, of itself, provide an improvement in runway incursion detection without being specifically tailored for this application.
Author
ENHANCED VISION; DISPLAY DEVICES; LOW VISIBILITY; AIRCRAFT SAFETY; APPROACH; AIRCRAFT LANDING
20090019725 NASA Johnson Space Center, Houston, TX, United States
The Lunar Regolith as a Remote Sensing Target for the Lunar Reconnaissance Orbiter (LRO)
Mendell, Wendell W.; [2009]; In English; Lunar Reconn. Orbiter Science Targeting Meeting, 9-11 Jun. 2009, Tempe, AZ, United States
Report No.(s): JSC-CN-18221; No Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090019725
Of the 6 instruments and one technology demonstration aboard the LRO, only CRaTER does not measure some kind of interaction of particles with the lunar regolith. LEND detects neutron fluence that contains information about the number density of protons in the upper regolith. To infer the presence of protons, the PI must assume a model that characterizes the surface as a collection of atoms. Thus, LEND does not sense the regolith as a structure. LROC, LOLA, and LAMP sense reflected photons whose wavelength is much shorter than the median particle size in the regolith. The photons interact with electrons, either in atomic shells or in chemical bonds. These interactions occur within a nanometer or so of the surface of a particle. Thus, the particles are macroscopic objects and models of the reflection process invoke ray-tracing optics. DIVINER senses photons that have been emitted by surface particles through thermal phonon processes. The wavelengths detected by the instrument are of the same order as the median particle size, and the photons contain information on particle dimensions as well as the molecular bonds in the constituent compounds. The Mini-RF synthetic aperture radar generates and detects photons of a few centimeters wavelength that interact with the regolith as a dielectric, the dielectric properties of the particulate component being described through effective medium theory. However, the interaction with rocks (macroscopic objects of interest to geologists) can be characterized using Fresnel or Mie models of electromagnetic properties.
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LUNAR ORBITER; REGOLITH; REMOTE SENSING; PLANETARY GEOLOGY; LUNAR ROCKS
20090019727 NASA Johnson Space Center, Houston, TX, United States
HSI in the Program Life Cycle
Fitts, David J.; May 05, 2009; In English; Aerospace Medical Association Annual Conference (AsMA 2009), 5 May 2009, Los Angeles, CA, United States; Original contains color illustrations
Report No.(s): JSC-CN-18280; No Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090019727
Human Systems Integration (HSI) in the Systems Engineering Life Cycle and the six capability model for the integration of human concerns is presented.
CASI
HUMAN FACTORS ENGINEERING; SYSTEMS INTEGRATION; NASA PROGRAMS; PROJECT MANAGEMENT
20090019730 NASA Wallops Flight Center, Wallops Island, VA, United States
The Mission Planning Lab: A Visualization and Analysis Tool
Daugherty, Sarah C.; Cervantes, Benjamin W.; [2009]; In English; SMC-IT-2009: Space Mission Challenges for Information Technology, 10-23 Jul. 2009, Pasadena, CA, United States; Original contains color illustrations
No Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090019730
Simulation and visualization are powerful decision tools that are time-saving and cost-effective. Space can be visualization of Aeronautics and Space Flight Facility (WFF) modeling, simulation, and project initiative called The Mission
Author
COMPUTERIZED SIMULATION; COMPUTER PROGRAMS; COST EFFECTIVENESS
20090019736 NASA Langley Research Center, Hampton, VA, United States
Fiber Optic Bragg Grating Sensors for Thermographic Detection of Subsurface Anomalies
May 04, 2009; In English; Aging Aircraft 2009 Conference, 4-7 May 2009, Kansas City, MO, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 645846.02.07.07.02
Report No.(s): LF99-7905; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090019736
Conventional thermography with an infrared imager has been shown to be an extremely viable technique for nondestructively detecting subsurface anomalies such as thickness variations due to corrosion. A recently developed technique using fiber optic sensors to measure temperature holds potential for performing similar inspections without requiring an infrared imager. The structure is heated using a heat source such as a quartz lamp with fiber Bragg grating (FBG) sensors at the surface of the structure to detect temperature. Investigated structures include a stainless steel plate with thickness variations simulated by small platelets attached to the back side using thermal grease. A relationship is shown between the FBG sensor thermal response and variations in material thickness. For comparison, finite element modeling was performed and found to agree closely with the fiber optic thermography results. This technique shows potential for applications where FBG sensors are already bonded to structures for Integrated Vehicle Health Monitoring (IVHM) strain measurements and can serve dual-use by also performing thermographic detection of subsurface anomalies.
Author
FIBER OPTICS; BRAGG GRATINGS; TEMPERATURE SENSORS; SURFACE TEMPERATURE; GEOTHERMAL ANOMALIES; THERMOGRAPHY; NONDESTRUCTIVE TESTS; STRUCTURAL HEALTH MONITORING; SMART STRUCTURES
20090019738 NASA Langley Research Center, Hampton, VA, United States
A Comparison of Surface Acoustic Wave Modeling Methods
Wilson, W. c.; Atkinson, G. M.; May 03, 2009; In English; Nanotech Conference and Exposition 2009, 3-7 May 2009, Houston, TX, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 645846.02.07.07.11.01
Report No.(s): LF99-8088; Copyright; Avail.: CASI: A01, Hardcopy
Surface Acoustic Wave (SAW) technology is low cost, rugged, lightweight, extremely low power and can be used to develop passive wireless sensors. For these reasons, NASA is investigating the use of SAW technology for Integrated Vehicle Health Monitoring (IVHM) of aerospace structures. To facilitate rapid prototyping of passive SAW sensors for aerospace applications, SAW models have been developed. This paper reports on the comparison of three methods of modeling SAWs. The three models are the Impulse Response Method a first order model, and two second order matrix methods; the conventional matrix approach, and a modified matrix approach that is extended to include internal finger reflections. The second order models are based upon matrices that were originally developed for analyzing microwave circuits using transmission line theory. Results from the models are presented with measured data from devices.
Author
SURFACE ACOUSTIC WAVE DEVICES; TECHNOLOGY ASSESSMENT; SENSORS; STRUCTURAL HEALTH MONITORING; SOUND WAVES; FREQUENCY RESPONSE; MATRIX METHODS; TRANSMISSION LINES; MICROWAVE CIRCUITS; ELECTRICAL ENGINEERING; AEROSPACE ENGINEERING
20090019743 NASA Dryden Flight Research Center, Edwards, CA, United States
Updating the Finite Element Model of the Aerostructures Test Wing Using Ground Vibration Test Data
Lung, Shun-Fat; Pak, Chan-Gi; April 2009; In English; Original contains color and black and white illustrations
Report No.(s): NASA/TM-2009-214646; H-2942; DFRC-963; Copyright; Avail.: CASI: A03, Hardcopy
Improved and/or accelerated decision making is a crucial step during flutter certification processes. Unfortunately, most finite element structural dynamics models have uncertainties associated with model validity. Tuning the finite element model using measured data to minimize the model uncertainties is a challenging task in the area of structural dynamics. The model tuning process requires not only satisfactory correlations between analytical and experimental results, but also the retention of the mass and stiffness properties of the structures. Minimizing the difference between analytical and experimental results is a type of optimization problem. By utilizing the multidisciplinary design, analysis, and optimization (MDAO) tool in order to optimize the objective function and constraints; the mass properties, the natural frequencies, and the mode shapes can be matched to the target data to retain the mass matrix orthogonality. This approach has been applied to minimize the model uncertainties for the structural dynamics model of the aerostructures test wing (ATW), which was designed and tested at the National Aeronautics and Space Administration Dryden Flight Research Center (Edwards, California). This study has shown that natural frequencies and corresponding mode shapes from the updated finite element model have excellent agreement with corresponding measured data.
Author
CERTIFICATION; MULTIDISCIPLINARY DESIGN OPTIMIZATION; DECISION MAKING; VIBRATION TESTS; GROUND TESTS; DYNAMIC STRUCTURAL ANALYSIS
20090019744 NASA Langley Research Center, Hampton, VA, United States
Single-Point Attachment Wind Damper for Launch Vehicle On-Pad Motion
Hrinda, Glenn A.; May 04, 2009; In English; 50th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 4-7 May 2009, Palm Springs, CA, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 136905.10.10.20.20
Report No.(s): LF99-8180; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090019744
A single-point-attachment wind-damper device is proposed to reduce on-pad motion of a cylindrical launch vehicle. The device is uniquely designed to attach at only one location along the vehicle and capable of damping out wind gusts from any lateral direction. The only source of damping is from two viscous dampers in the device. The effectiveness of the damper design in reducing vehicle displacements is determined from transient analysis results using an Ares I-X launch vehicle. Combinations of different spring stiffnesses and damping are used to show how the vehicle's displacement response is significantly reduced during a wind gust.
Author
LAUNCH VEHICLES; DISPLACEMENT; LAUNCHING PADS; GROUND WIND; OSCILLATION DAMPERS; LOADS (FORCES); BENDING; STRUCTURAL DESIGN
20090019745 NASA Dryden Flight Research Center, Edwards, CA, United States
NASA Global Hawk: A New Tool for Earth Science Research
Naftel, J. Chris; May 2009; In English; 33rd International Symposium on Remote Sensing of Environment, 4-8 May 2009, Stresa, Italy
Report No.(s): NASA/TM-2009-214647; H-2951; DFRC-960; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090019745
Scientists have eagerly anticipated the performance capability of the National Aeronautics and Space Administration (NASA) Global Hawk for over a decade. In 2009 this capability becomes operational. One of the most desired performance capabilities of the Global Hawk aircraft is very long endurance. The Global Hawk aircraft can remain airborne longer than almost all other jet-powered aircraft currently flying, and longer than all other aircraft available for airborne science use. This paper describes the NASA Global Hawk system, payload accommodations, concept of operations, and the first scientific data-gathering mission: Global Hawk Pacific 2009.
Author
EARTH SCIENCES; JET AIRCRAFT; RESEARCH AIRCRAFT; NASA PROGRAMS; PAYLOADS
20090019746 NASA Langley Research Center, Hampton, VA, United States
Thermal Analysis and Testing of Candidate Materials for PAIDAE Inflatable Aeroshell
DelCorso, Joseph A.; Bruce, Walter E., III; Liles, Kaitlin A.; Hughes, Stephen J.; May 04, 2009; In English; 20th AIAA Aerodynamic Decelerator Systems Technology Conference, 4-7 May 2009, Seattle, WA, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 599489.02.07.07.02.03.77
Report No.(s): LF99-8353; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090019746
The Program to Advance Inflatable-Decelerators for Atmospheric Entry (PAIDAE) is a NASA project tasked with developing and evaluating viable inflatable-decelerator aeroshell geometries and materials. Thermal analysis of material layups supporting an inflatable aeroshell was completed in order to identify expected material response, failure times, and to establish an experimental test matrix to keep barrier layer materials from reaching critical temperature limits during thermal soak. Material layups were then tested in the 8- foot High Temperature Tunnel (8'HTT), where they were subjected to hypersonic aerothermal heating conditions, similar to those expected for a Mars entry. This paper presents a broad overview of the thermal analysis supporting multiple materials, and layup configurations tested in the 8'HTT at flight conditions similar to those that would be experienced during Mars entry trajectories. Direct comparison of TPS samples tested in the 8'HTT verify that the thermal model accurately predicted temperature profiles when there are up to four materials in the test layup. As the number of material layers in each test layup increase (greater than 4), the accuracy of the prediction decreases significantly. The inaccuracy of the model predictions for layups with more than four material layers is believed to be a result of the contact resistance values used throughout the model being inaccurate. In addition, the harsh environment of the 8'HTT, including hot gas penetrating through the material layers, could also be a contributing factor.
Author
ATMOSPHERIC ENTRY SIMULATION; INFLATABLE STRUCTURES; BRAKES (FOR ARRESTING MOTION); AEROSHELLS; REENTRY SHIELDING; SPACECRAFT SHIELDING; THERMAL PROTECTION; MATERIALS SELECTION; THERMAL ANALYSIS
20090019749 NASA Dryden Flight Research Center, Edwards, CA, United States
Technology Advancements Enhance Aircraft Support of Experiment Campaigns
Vachon, Jacques J.; March 02, 2009; In English; 33rd International Symposium on Remote Sensing of Environment, 4-8 May 2009, Stresa, Italy; Original contains black and white illustrations
Report No.(s): DFRC-922; No Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090019749
For over 30 years, the NASA Airborne Science Program has provided airborne platforms for space bound instrument development, for calibrating new and existing satellite systems, and for making in situ and remote sensing measurements that can only be made from aircraft. New technologies have expanded the capabilities of aircraft that are operated for these missions. Over the last several years a new technology investment portfolio has yielded improvements that produce better measurements for the airborne science communities. These new technologies include unmanned vehicles, precision trajectory control and advanced telecommunications capabilities. We will discuss some of the benefits of these new technologies and systems which aim to provide users with more precision, lower operational costs, quicker access to data, and better management of multi aircraft and multi sensor campaigns.
Author
FLYING PLATFORMS; TRAJECTORY CONTROL; REMOTE SENSING; TELECOMMUNICATION; CALIBRATING
20090019750 NASA Langley Research Center, Hampton, VA, United States
Calculation of Stress Intensity Factors for Interfacial Cracks in Fiber Metal Laminates
Wang, John T.; May 04, 2009; In English; 50th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 4-7 May 2009, Palm Springs, CA, United States; Original contains color illustrations
Contract(s)/Grant(s): WBS 6982590207070302
Report No.(s): LF99-8529; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090019750
Stress intensity factors for interfacial cracks in Fiber Metal Laminates (FML) are computed by using the displacement ratio method recently developed by Sun and Qian (1997, Int. J. Solids. Struct. 34, 2595-2609). Various FML configurations with single and multiple delaminations subjected to different loading conditions are investigated. The displacement ratio method requires the total energy release rate, bimaterial parameters, and relative crack surface displacements as input. Details of generating the energy release rates, defining bimaterial parameters with anisotropic elasticity, and selecting proper crack surface locations for obtaining relative crack surface displacements are discussed in the paper. Even though the individual energy release rates are nonconvergent, mesh-size-independent stress intensity factors can be obtained. This study also finds that the selection of reference length can affect the magnitudes and the mode mixity angles of the stress intensity factors; thus, it is important to report the reference length used with the calculated stress intensity factors.
Author
STRESS INTENSITY FACTORS; CRACKS; ELASTIC PROPERTIES; LAMINATES; DELAMINATING; LOADS (FORCES)
20090019753 NASA Dryden Flight Research Center, Edwards, CA, United States
The Open Source DataTurbine Initiative: Streaming Data Middleware for Environmental Observing Systems
Fountain T.; Shin, S.; Shin, P.; Hubbard, P.; Freudinger, L.; May 04, 2009; In English; 33rd International Symposim on Remote Sensing of Environment, 4-9 May 2009, Stresa, Italy; Original contains color illustrations
Contract(s)/Grant(s): NSF OCI-0722067; NSF BDI-0756920; NSF OISE-0314015; NSF OISE-0627026; NSF OISE-0546802; NSF OISE-0446017WBS 769134.03.02.03.02
Report No.(s): DFRC-999; Copyright; Avail.: CASI: A02, Hardcopy
The Open Source DataTurbine Initiative is an international community of scientists and engineers sharing a common interest in real-time streaming data middleware and applications. The technology base of the OSDT Initiative is the DataTurbine open source middleware. Key applications of DataTurbine include coral reef monitoring, lake monitoring and limnology, biodiversity and animal tracking, structural health monitoring and earthquake engineering, airborne environmental monitoring, and environmental sustainability. DataTurbine software emerged as a commercial product in the 1990 s from collaborations between NASA and private industry. In October 2007, a grant from the USA National Science Foundation (NSF) Office of Cyberinfrastructure allowed us to transition DataTurbine from a proprietary software product into an open source software initiative. This paper describes the DataTurbine software and highlights key applications in environmental monitoring.
Author
APPLICATIONS PROGRAMS (COMPUTERS); REAL TIME OPERATION; DATA SYSTEMS; ENVIRONMENTAL MONITORING; STRUCTURAL ENGINEERING
20090019755 NASA Langley Research Center, Hampton, VA, United States
Deployable Aeroshell Flexible Thermal Protection System Testing
Hughes, Stephen J.; Ware, Joanne S.; DelCorso, Joseph A.; Lugo, Rafael A.; May 04, 2009; In English; 20th AIAA Aerodynamic Decelerator Systems Technology Conference, 4-7 May 2009, Seattle, WA, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 599489.02.07.07.02.03.77
Report No.(s): LF99-8607; Copyright; Avail.: CASI: A03, Hardcopy
Deployable aeroshells offer the promise of achieving larger aeroshell surface areas for entry vehicles than otherwise attainable without deployment. With the larger surface area comes the ability to decelerate high-mass entry vehicles at relatively low ballistic coefficients. However, for an aeroshell to perform even at the low ballistic coefficients attainable with deployable aeroshells, a flexible thermal protection system (TPS) is required that is capable of surviving reasonably high heat flux and durable enough to survive the rigors of construction handling, high density packing, deployment, aerodynamic loading and aerothermal heating. The Program for the Advancement of Inflatable Decelerators for Atmospheric Entry (PAIDAE) is tasked with developing the technologies required to increase the technology readiness level (TRL) of inflatable deployable aeroshells, and one of several of the technologies PAIDAE is developing for use on inflatable aeroshells is flexible TPS. Several flexible TPS layups were designed, based on commercially available materials, and tested in NASA Langley Research Center's 8 Foot High Temperature Tunnel (8ft HTT). The TPS layups were designed for, and tested at three different conditions that are representative of conditions seen in entry simulation analyses of inflatable aeroshell concepts. Two conditions were produced in a single run with a sting-mounted dual wedge test fixture. The dual wedge test fixture had one row of sample mounting locations (forward) at about half the running length of the top surface of the wedge. At about two thirds of the running length of the wedge, a second test surface drafted up at five degrees relative to the first test surface established the remaining running length of the wedge test fixture. A second row of sample mounting locations (aft) was positioned in the middle of the running length of the second test surface. Once the desired flow conditions were established in the test section the dual wedge test fixture, oriented at 5 degrees angle of attack down, was injected into the flow. In this configuration the aft sample mounting location was subjected to roughly twice the heat flux and surface pressure of the forward mounting location. The tunnel was run at two different conditions for the test series: 1) 'Low Pressure', and 2) 'High Pressure'. At 'Low Pressure' conditions the TPS layups were tested at 6W/cm2 and 11W/cm2 while at 'High Pressure' conditions the TPS layups were tested at 11W/cm2 and 20W/cm2. This paper details the test configuration of the TPS samples in the 8Ft HTT, the sample holder assembly, TPS sample layup construction, sample instrumentation, results from this testing, as well as lessons learned.
Author
AEROSHELLS; DEPLOYMENT; THERMAL PROTECTION; SYSTEMS ENGINEERING; PERFORMANCE TESTS; TECHNOLOGY ASSESSMENT; HEAT SHIELDING; SPACECRAFT SHIELDING; COMPUTATIONAL FLUID DYNAMICS; ATMOSPHERIC ENTRY; AERODYNAMIC HEATING; AERODYNAMIC BRAKES; SPACECRAFT DESIGN; AEROSPACE ENGINEERING
20090019757 NASA Langley Research Center, Hampton, VA, United States
Nonlinear Reduced-Order Simulation Using Stress-Free and Pre-Stressed Modal Bases
Przekop, Adam; Stover, Michael A.; Rizzi, Stephen A.; May 04, 2009; In English; 50th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 4-7 May 2009, Palm Springs, CA, United States; Original contains color illustrations
Contract(s)/Grant(s): WBS 599489.02.07.07.02.66
Report No.(s): AIAA Paper-2009-2435; LF99-7452; Copyright; Avail.: CASI: A03, Hardcopy
A study is undertaken to determine the advantages and disadvantages associated with application of stress-free and pre-stressed modal bases in a reduced-order finite-element-based nonlinear simulation. A planar beam is chosen as an application example and its response due to combined thermal and random pressure loadings is examined. Combinations of two random pressure levels and two thermal conditions are investigated. The latter consists of an ambient temperature condition and an elevated temperature condition in the post-buckled regime. It is found that stress-free normal modes establish a broadly applicable modal basis yielding accurate results for all the loading regimes considered. In contrast, the range of applicability for a thermally pre-stressed modal basis is found to be limited. The behavior is explained by scrutinizing the coupling found in the linear stiffness and the effect this coupling has on the structural response characteristics under the range of loading conditions considered.
Author
NONLINEARITY; REDUCED ORDER FILTERS; FINITE ELEMENT METHOD; PLANAR STRUCTURES; BEAMS (SUPPORTS); BUCKLING; ACOUSTIC FATIGUE; THERMAL STRESSES; COUPLED MODES; DYNAMIC RESPONSE; DYNAMIC STRUCTURAL ANALYSIS; STRUCTURAL ENGINEERING; MODAL RESPONSE; MATHEMATICAL MODELS
20090019769 NASA Johnson Space Center, Houston, TX, United States
Low-Load Resistance Training with Blood Flow Occlusion as a Countermeasure to Disuse Atrophy
Ploutz-Snyder, L. L.; Cook, S. B.; May 27, 2009; In English; American College of Sports Medicine meeting, 27-30 May 2009, Seattle, WA, United States
Report No.(s): JSC-CN-18253; Copyright; Avail.: CASI: A01, Hardcopy
Decreases in strength and neuromuscular function are observed following prolonged disuse. Exercise countermeasures to prevent muscle dysfunction during disuse typically involve high intensity resistance training. The purpose of the study is to evaluate the effectiveness of low-load resistance training with a blood flow occlusion to mitigate muscle loss and dysfunction during 30 days of unilateral lower limb suspension (ULLS).
Author
ATROPHY; NEUROMUSCULAR TRANSMISSION; WORKLOADS (PSYCHOPHYSIOLOGY); BLOOD FLOW; OCCLUSION; COUNTERMEASURES; FLOW RESISTANCE; PHYSICAL EXERCISE; EDUCATION
20090019792 NASA Langley Research Center, Hampton, VA, United States
Aerodynamic and Aeroelastic Characteristics of a Tension Cone Inflatable Aerodynamic Decelerator
Clark, Ian G.; Cruz, Juan R.; Hughes, Monica F.; Ware, Joanne S.; Madlangbayan, Albert; Braun, Robert D.; May 04, 2009; In English; 20th AIAA Aerodynamic Decelerator Systems Technology Conference, 4-7 May 2009, Seattle, WA, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 984754.02.07.07.22.05
Report No.(s): AIAA Paper 2009-2967; LF99-8534; Copyright; Avail.: CASI: A03, Hardcopy
The supersonic aerodynamic and aeroelastic characteristics of a tension cone inflatable aerodynamic decelerator were investigated by wind tunnel testing. Two sets of tests were conducted: one using rigid models and another using textile models. Tests using rigid models were conducted over a Mach number range from 1.65 to 4.5 at angles of attack from -12 to 20 degrees. The axial, normal, and pitching moment coefficients were found to be insensitive to Mach number over the tested range. The axial force coefficient was nearly constant (C(sub A) = 1.45 +/- 0.05) with respect to angle of attack. Both the normal and pitching moment coefficients were nearly linear with respect to angle of attack. The pitching moment coefficient showed the model to be statically stable about the reference point. Schlieren images and video showed a detached bow shock with no evidence of large regions of separated flow and/or embedded shocks at all Mach numbers investigated. Qualitatively similar static aerodynamic coefficient and flow visualization results were obtained using textile models at a Mach number of 2.5. Using inflatable textile models the torus pressure required to maintain the model in the fully-inflated configuration was determined. This pressure was found to be sensitive to details in the structural configuration of the inflatable models. Additional tests included surface pressure measurements on rigid models and deployment and inflation tests with inflatable models.
Author
AERODYNAMIC BRAKES; INFLATABLE STRUCTURES; CONES; AEROELASTICITY; AERODYNAMICS; SUPERSONIC WIND TUNNELS; WIND TUNNEL TESTS; ATMOSPHERIC ENTRY; COMPUTATIONAL FLUID DYNAMICS; TOROIDAL SHELLS; DEPLOYMENT
20090020162 NASA Marshall Space Flight Center, Huntsville, AL, United States
A Review of Lunar Meteorite Impact-Melt Clast Compositions and Ages
Cohen, Barbara A.; September 15, 2008; In English; Workshop on the Early Solar System Impact Bombardment, 15-16 Sep. 2008, Houston, TX, United States; Original contains black and white illustrations
Report No.(s): MSFC-2067; No Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020162
One of the important outstanding goals of lunar science is understanding the bombardment history of the Moon and calibrating the impact flux curve for extrapolation to the Earth and other terrestrial planets. Obtaining a sample from a carefully-characterized interior melt sheet or ring massif is a reliable way to tell a single crater's age. A different but complementary approach is to use extensive laboratory characterization (microscopic, geochemical, isotopic) of float samples to understand the integrated impact history of a region. Both approaches have their merits and limitations. In essence, the latter is the approach we have used to understand the impact history of the Feldspathic Highland Terrain (FHT) as told by lunar feldspathic meteorites.
Derived from text
IMPACT MELTS; METEORITE COLLISIONS; METEORITES; MOON; LUNAR CRATERS; METEORITE CRATERS; SELENOLOGY; METEORITIC DAMAGE; GEOCHRONOLOGY
20090020184 NASA Marshall Space Flight Center, Huntsville, AL, United States
LOCAD-PTS: Operation of a New System for Microbial Monitoring Aboard the International Space Station (ISS)
Maule, J.; Wainwright, N.; Steele, A.; Gunter, D.; Flores, G.; Effinger, M.; Danibm N,; Wells, M.; Williams, S.; Morris, H.; Monaco, L.; September 09, 2008; In English; AIAA Space 2008 Conference and Exposition, 9-11 Sep. 2008, San Diego, CA, United States; Original contains color illustrations
Report No.(s): MSFC-2081-1; MSFC-2081-2; Copyright; Avail.: CASI: A02, Hardcopy
Microorganisms within the space stations Salyut, Mir and the International Space Station (ISS), have traditionally been monitored with culture-based techniques. These techniques involve growing environmental samples (cabin water, air or surfaces) on agar-type media for several days, followed by visualization of resulting colonies; and return of samples to Earth for ground-based analysis. This approach has provided a wealth of useful data and enhanced our understanding of the microbial ecology within space stations. However, the approach is also limited by the following: i) More than 95% microorganisms in the environment cannot grow on conventional growth media; ii) Significant time lags occur between onboard sampling and colony visualization (3-5 days) and ground-based analysis (as long as several months); iii) Colonies are often difficult to visualize due to condensation within contact slide media plates; and iv) Techniques involve growth of potentially harmful microorganisms, which must then be disposed of safely. This report describes the operation of a new culture-independent technique onboard the ISS for rapid analysis (within minutes) of endotoxin and -1, 3-glucan, found in the cell walls of gram-negative bacteria and fungi, respectively. This technique involves analysis of environmental samples with the Limulus Amebocyte Lysate (LAL) assay in a handheld device. This handheld device and sampling system is known as the Lab-On-a-Chip Application Development Portable Test System (LOCAD-PTS). A poster will be presented that describes a comparative study between LOCAD-PTS analysis and existing culture-based methods onboard the ISS; together with an exploratory survey of surface endotoxin throughout the ISS. It is concluded that while a general correlation between LOCAD-PTS and traditional culture-based methods should not necessarily be expected, a combinatorial approach can be adopted where both sets of data are used together to generate a more complete story of the microbial ecology on the ISS.
Author
MICROBIOLOGY; MICROFLUIDIC DEVICES; MICROORGANISMS
Additions to the NASA Aeronautics and Space Database as of 06/03/2009
20090020280 NASA Johnson Space Center, Houston, TX, United States
"Fly-by-Wireless" and Wireless Sensors Update
Studor, George F.; April 16, 2009; In English; JANNAF Wireless Sensors Working Group Meeting, 16-17 Apr. 2009, Las Vegas. NV, United States; Original contains color illustrations
Contract(s)/Grant(s): WBS 869021.05.05.01.04
Report No.(s): JSC-CN-18195; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020280
This slide presentation reviews the uses of wires in the Aerospace industry. The vision is to minimize cables and connectors and increase functionality across the aerospace industry by providing reliable lower cost modular and higher performance alternatives to wired data connectivity to benefit the entire vehicle and program
CASI
AEROSPACE INDUSTRY; WIRE; FLIGHT CONTROL
20090020362 NASA Glenn Research Center, Cleveland, OH, United States
Prediction of Turbulence-Generated Noise in Unheated Jets Part 2 JeNo Users' Manual (Version 1.0)
Khavaran, Abbas; Wolter, John D.; Koch, L. Danielle; April 2009; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 984754.02.07.03.17.02
Report No.(s): NASA/TM-2009-213827/PART2; E-16951; Copyright; Avail.: CASI: A03, Hardcopy
JeNo (Version 1.0) is a Fortran90 computer code that calculates the far-field sound spectral density produced by axisymmetric, unheated jets at a user specified observer location and frequency range. The user must provide a structured computational grid and a mean flow solution from a Reynolds-Averaged Navier Stokes (RANS) code as input. Turbulence kinetic energy and its dissipation rate from a k-epsilon or k-omega turbulence model must also be provided. JeNo is a research code, and as such, its development is ongoing. The goal is to create a code that is able to accurately compute far-field sound pressure levels for jets at all observer angles and all operating conditions. In order to achieve this goal, current theories must be combined with the best practices in numerical modeling, all of which must be validated by experiment. Since the acoustic predictions from JeNo are based on the mean flow solutions from a RANS code, quality predictions depend on accurate aerodynamic input.This is why acoustic source modeling, turbulence modeling, together with the development of advanced measurement systems are the leading areas of research in jet noise research at NASA Glenn Research Center.
Author
COMPUTER PROGRAMS; TURBULENCE MODELS; REYNOLDS AVERAGING; SOUND PRESSURE; KINETIC ENERGY; JET AIRCRAFT NOISE; NOISE PREDICTION
20090020365 NASA Johnson Space Center, Houston, TX, United States
NASA Human Research Program: Behavioral Health and Performance Program Element
Leveton, Lauren B.; May 11, 2009; In English; 80th Annual Scientific Meeting of the Aerospace Medical Association, 3-7 May 2009, Los Angeles, CA, United States; Original contains color and black and white illustrations
Report No.(s): JSC-CN-18277; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020365
This viewgraph presentation reviews the performance errors associated with sleep loss, fatigue and psychomotor factors during manned space flight. Short and long term behavioral health factors are also addressed
CASI
MANNED SPACE FLIGHT; INTERNATIONAL SPACE STATION; HUMAN BEHAVIOR; HUMAN FACTORS ENGINEERING; AEROSPACE MEDICINE
20090020366 NASA Glenn Research Center, Cleveland, OH, United States
Experimental Investigations of Space Shuttle BX-265 Foam
Lerch, Bradley A.; Sullivan, Roy M.; April 2009; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 524238.08.02.03.04
Report No.(s): NASA/TM-2009-215292; E-16572; No Copyright; Avail.: CASI: A04, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020366
This report presents a variety of experimental studies on the polyurethane foam, BX-265. This foam is used as a close-out foam insulation on the space shuttle external tank. The purpose of this work is to provide a better understanding of the foam s behavior and to support advanced modeling efforts. The following experiments were performed: Thermal expansion was measured for various heating rates. The in situ expansion of foam cells was documented by heating the foam in a scanning electron microscope. Expansion mechanisms are described. Thermogravimetric analysis was performed at various heating rates and for various environments. The glass transition temperature was also measured. The effects of moisture on the foam were studied. Time-dependent effects were measured to give preliminary data on viscoelastoplastic properties.
Author
POLYURETHANE FOAM; EXTERNAL TANKS; ELASTOPLASTICITY; THERMAL EXPANSION; VISCOELASTICITY; THERMOGRAVIMETRY
20090020369 Analex Corp., Brook Park, OH, United States
Power System Mass Analysis for Hydrogen Reduction Oxygen Production on the Lunar Surface
Colozza, Anthony J.; April 2009; In English; Original contains color illustrations
Contract(s)/Grant(s): NNC06BA07BWBS 604746.04.03.03
Report No.(s): NASA/CR-2009-215504; E-16667; Copyright; Avail.: CASI: A03, Hardcopy
The production of oxygen from the lunar regolith requires both thermal and electrical power in roughly similar proportions. This unique power requirement is unlike most applications on the lunar surface. To efficiently meet these requirements, both solar PV array and solar concentrator systems were evaluated. The mass of various types of photovoltaic and concentrator based systems were calculated to determine the type of power system that provided the highest specific power. These were compared over a range of oxygen production rates. Also a hybrid type power system was also considered. This system utilized a photovoltaic array to produce the electrical power and a concentrator to provide the thermal power. For a single source system the three systems with the highest specific power were a flexible concentrator/Stirling engine system, a rigid concentrator/Stirling engine system and a tracking triple junction solar array system. These systems had specific power values of 43, 34, and 33 W/kg, respectively. The hybrid power system provided much higher specific power values then the single source systems. The best hybrid combinations were the triple junction solar array with the flexible concentrator and the rigid concentrator. These systems had a specific power of 81 and 68 W/kg, respectively.
Author
SOLAR COLLECTORS; SOLAR ARRAYS; CONCENTRATORS; OXYGEN PRODUCTION; SYSTEMS ANALYSIS; HYDROGEN PRODUCTION
20090020371 NASA Glenn Research Center, Cleveland, OH, United States
Supporting Technology at GRC to Mitigate Risk as Stirling Power Conversion Transitions to Flight
Schreiber, Jeffrey G.; Thieme, Lanny G.; Wong, Wayne A.; April 2009; In English; Sixth International Energy Conversion Engineering Conference (IECEC), 28-30 Jul. 2008, Cleveland, OH, United States; Original contains color illustrations
Contract(s)/Grant(s): WBS 138494.04.01.01
Report No.(s): NASA/TM-2009-215515; AIAA Paper 2008-5790; E-16817; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020371
Stirling power conversion technology has been reaching more advanced levels of maturity during its development for space power applications. The current effort is in support of the Advanced Stirling Radioisotope Generator (ASRG), which is being developed by the U.S. Department of Energy (DOE), Lockheed Martin Space Systems Company (LMSSC), Sunpower Inc., and the NASA Glenn Research Center (GRC). This generator would use two high-efficiency Advanced Stirling Convertors (ASCs) to convert thermal energy from a radioisotope heat source into electricity. Of paramount importance is the reliability of the power system and as a part of this, the Stirling power convertors. GRC has established a supporting technology effort with tasks in the areas of reliability, convertor testing, high-temperature materials, structures, advanced analysis, organics, and permanent magnets. The project utilizes the matrix system at GRC to make use of resident experts in each of the aforementioned fields. Each task is intended to reduce risk and enhance reliability of the convertor as this technology transitions toward flight status. This paper will provide an overview of each task, outline the recent efforts and accomplishments, and show how they mitigate risk and impact the reliability of the ASC s and ultimately, the ASRG.
Author
STIRLING CYCLE; THERMAL ENERGY; RADIOISOTOPE HEAT SOURCES; TECHNOLOGY UTILIZATION; AEROSPACE SYSTEMS; ELECTRICITY
20090020372 NASA Langley Research Center, Hampton, VA, United States
An Argument Against Augmenting the Lagrangean for Nonholonomic Systems
Roithmayr, Carlos M.; Hodges, Dewey H.; Journal of Applied Mechanics; March 9, 2009; vol. Volume 73; issue No. 3; pp. 034501-03450; In English; Original contains black and white illustrations
Contract(s)/Grant(s): WBS 992858.13.07.02
Report No.(s): LF99-4587; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://dx.doi.org/10.1115/1.3086435
Although it is known that correct dynamical equations of motion for a nonholonomic system cannot be obtained from a Lagrangean that has been augmented with a sum of the nonholonomic constraint equations weighted with multipliers, previous publications suggest otherwise. An example has been proposed in support of augmentation and purportedly demonstrates that an accepted method fails to produce correct equations of motion whereas augmentation leads to correct equations; this paper shows that in fact the opposite is true. The correct equations, previously discounted on the basis of a flawed application of the Newton-Euler method, are verified by using Kane's method and a new approach to determining the directions of constraint forces. A correct application of the Newton-Euler method reproduces valid equations.
Author
NONHOLONOMIC EQUATIONS; VARIATIONAL PRINCIPLES; DYNAMICAL SYSTEMS; EQUATIONS OF MOTION; NEWTON METHODS
20090020375 NASA Langley Research Center, Hampton, VA, United States
Replica-Based Crack Inspection
Newman, John A.; Willard, Scott A.; Smith, Stephen W.; Piascik, Robert S.; Engineering Fracture Mechanics; December 25, 2008; vol. Volume 76; issue Issue 7; pp. 898-91; In English; Original contains color and black and white illustrations
Report No.(s): LF99-7363; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://dx.doi.org/10.1016/j.engfracmech.2008.12.012
Surface replication has been proposed as a method for crack detection in space shuttle main engine flowliner slots. The results of a feasibility study show that examination of surface replicas with a scanning electron microscope can result in the detection of cracks as small as 0.005 inch, and surface flaws as small as 0.001 inch, for the flowliner material.
Author
SPACE SHUTTLE MAIN ENGINE; LININGS; CRACKS; SURFACE DEFECTS; REPLICAS; FAULT DETECTION
20090020378 NASA Glenn Research Center, Cleveland, OH, United States
Use of the Delay-Tolerant Networking Bundle Protocol from Space
Wood, Lloyd; Ivancic, William D.; Eddy, Wesley M.; Stewart, Dave; Northam, James; Jackson, Chris; daSilvaCuriel, Alex; April 2009; In English; 59th International Astronautical Congress and Exhibition 2008 (IAC), 29 Sep. - 3 Oct. 2008, Glasgow, Scotland, United Kingdom; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 439432.04.19.01.01
Report No.(s): NASA/TM-2009-215582; IAC-08-B2.3.10; E-16810; Copyright; Avail.: CASI: A03, Hardcopy
The Disaster Monitoring Constellation (DMC), constructed by Survey Satellite Technology Ltd (SSTL), is a multisatellite Earth-imaging low-Earth-orbit sensor network where captured image swaths are stored onboard each satellite and later downloaded from the satellite payloads to a ground station. Store-and-forward of images with capture and later download gives each satellite the characteristics of a node in a Delay/Disruption Tolerant Network (DTN). Originally developed for the Interplanetary Internet, DTNs are now under investigation in an Internet Research Task Force (IRTF) DTN research group (RG), which has developed a bundle architecture and protocol. The DMC is currently unique in its adoption of the Internet Protocol (IP) for its imaging payloads and for satellite command and control, based around reuse of commercial networking and link protocols. These satellites use of IP has enabled earlier experiments with the Cisco router in Low Earth Orbit (CLEO) onboard the constellation's UK-DMC satellite. Earth images are downloaded from the satellites using a custom IPbased high-speed transfer protocol developed by SSTL, Saratoga, which tolerates unusual link environments. Saratoga has been documented in the Internet Engineering Task Force (IETF) for wider adoption. We experiment with use of DTNRG bundle concepts onboard the UKDMC satellite, by examining how Saratoga can be used as a DTN convergence layer to carry the DTNRG Bundle Protocol, so that sensor images can be delivered to ground stations and beyond as bundles. This is the first successful use of the DTNRG Bundle Protocol in a space environment. We use our practical experience to examine the strengths and weaknesses of the Bundle Protocol for DTN use, paying attention to fragmentation, custody transfer, and reliability issues.
Author
PROTOCOL (COMPUTERS); COMPUTER NETWORKS; COMPUTER SECURITY; INTERNETS; ARCHITECTURE (COMPUTERS)
20090020381 NASA Glenn Research Center, Cleveland, OH, United States
Data Processing for Atmospheric Phase Interferometers
Acosta, Roberto J.; Nessel, James A.; Morabito, David D.; April 2009; In English; Original contains color illustrations
Contract(s)/Grant(s): WBS 439432.04.12.01
Report No.(s): NASA/TM-2009-215599; E-16890; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020381
This paper presents a detailed discussion of calibration procedures used to analyze data recorded from a two-element atmospheric phase interferometer (API) deployed at Goldstone, California. In addition, we describe the data products derived from those measurements that can be used for site intercomparison and atmospheric modeling. Simulated data is used to demonstrate the effectiveness of the proposed algorithm and as a means for validating our procedure. A study of the effect of block size filtering is presented to justify our process for isolating atmospheric fluctuation phenomena from other system-induced effects (e.g., satellite motion, thermal drift). A simulated 24 hr interferometer phase data time series is analyzed to illustrate the step-by-step calibration procedure and desired data products.
Author
ATMOSPHERIC MODELS; DATA PROCESSING; INTERFEROMETERS; ALGORITHMS; CALIBRATING
Additions to the NASA Aeronautics and Space Database as of 06/04/2009
20090020391 NASA Dryden Flight Research Center, Edwards, CA, United States
The Unique Capabilities of the Global Hawk Aircraft for the Study of Climate Changes
Cairo, F.; Carli, Bruno; Curry, Robert; May 04, 2009; In English; 33rd International Symposium on Remote Sensing of Environment, 4-8 May 2009, Stresa, Italy
Report No.(s): DFRC-921; Copyright; Avail.: CASI: A01, Hardcopy
Due to unprecedented extent and flexibility of the coverage that is now attainable both in space and time, stratospheric unmanned aircraft, such as the Global Hawk (GH), offers new opportunities for the study of climate changes. The capability of performing long flights at altitudes close to the boundary conditions of radiative processes, and of following the diurnal variation of chemical species and clouds, make the GH competitive with LEO and geosynchronous satellites, and even capable of new observations that are not possible from satellites. This paper discusses how the GH can be used to make relevant advancements in most of the issues that are related to climate change studies, such as: Earth Radiation Budget, Water Cycle, Ecosystems and Upper Troposphere-Lower Stratosphere, as well as to the monitoring and control of Greenhouse Gases and Air Quality . Collaboration between NASA and Italian scientific institutions, within the framework of the US.-Italy Cooperation on Climate Change, is providing the opportunity to rapidly deploy new instruments on the GH and to possibly operate the aircraft from an Italian site in the Mediterranean area. From this area, which is considered highly vulnerable to climate change, meridional transects would allow the crossing of Polar and Sub Tropical Jets, as well as a complete crossing of the Inter Tropical Convergence Zone, while latitudinal ones would follow the influx from Asia and North America. Regions otherwise difficult to access, such as Central Africa and the Tibetan Plateau, could be reached and better investigated. An overview of these new opportunities will be given and discussed.
Author
CLIMATE CHANGE; PILOTLESS AIRCRAFT; STRATOSPHERE; TROPOSPHERE
20090020392 NASA Glenn Research Center, Cleveland, OH, United States
Numerical Analysis of Film Cooling at High Blowing Ratio
El-Gabry, Lamyaa; Heidmann, James; Ameri, Ali; April 2009; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 561581.02.08.03.21.02
Report No.(s): NASA/TM-2009-215517; E-16822; Copyright; Avail.: CASI: A03, Hardcopy
Computational Fluid Dynamics is used in the analysis of a film cooling jet in crossflow. Predictions of film effectiveness are compared with experimental results for a circular jet at blowing ratios ranging from 0.5 to 2.0. Film effectiveness is a surface quantity which alone is insufficient in understanding the source and finding a remedy for shortcomings of the numerical model. Therefore, in addition, comparisons are made to flow field measurements of temperature along the jet centerline. These comparisons show that the CFD model is accurately predicting the extent and trajectory of the film cooling jet; however, there is a lack of agreement in the near-wall region downstream of the film hole. The effects of main stream turbulence conditions, boundary layer thickness, turbulence modeling, and numerical artificial dissipation are evaluated and found to have an insufficient impact in the wake region of separated films (i.e. cannot account for the discrepancy between measured and predicted centerline fluid temperatures). Analyses of low and moderate blowing ratio cases are carried out and results are in good agreement with data.
Author
COMPUTATIONAL FLUID DYNAMICS; FILM COOLING; NUMERICAL ANALYSIS; MATHEMATICAL MODELS; SPANWISE BLOWING
20090020393 NASA Marshall Space Flight Center, Huntsville, AL, United States
NASA Ares I Crew Launch Vehicle Upper Stage Avionics and Software Overview
Nola, Charles L.; Blue, Lisa; July 20, 2008; In English; 44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, 20-23 Jul. 2008, Hartford, CT, United States; Original contains color illustrations
No Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020393
Building on the heritage of the Saturn and Space Shuttle Programs for the Design, Development, Test, and Evaluation (DDT and E) of avionics and software for NASA's Ares I Crew Launch Vehicle (CLV), the Ares I Upper Stage Element is a vital part of the Constellation Program's transportation system. The Upper Stage Element's Avionics Subsystem is actively proceeding toward its objective of delivering a flight-certified Upper Stage Avionics System for the Ares I CLV.
Author
ARES 1 LAUNCH VEHICLE; ARES 1 UPPER STAGE; ASTRIONICS; COMPUTER PROGRAMS; SOFTWARE ENGINEERING; COMPUTER SYSTEMS DESIGN; SYSTEMS ENGINEERING; AEROSPACE ENGINEERING
20090020399 NASA Goddard Space Flight Center, Greenbelt, MD, United States
NEOCAM: Near Earth Object Chemical Analysis Mission: Bridging the Gulf between Telescopic Observations and the Chemical and Mineralogical Compositions of Asteroids or Diogenes A: Diagnostic Observation of the Geology of Near Earth Spectrally-Classified Asteroids
Nuth, Joseph A.; April 20, 2009; In English; Committee to review Near-Earth Object Surveys and Hazard Mitigation Strategies: Survey/Detection Panel/NAS/NRC, 20-21 Apr. 2009, Tucson, AZ, United States
No Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020399
Studies of meteorites have yielded a wealth of scientific information based on highly detailed chemical and isotopic studies possible only in sophisticated terrestrial laboratories. Telescopic studies have revealed an enormous (greater than 10(exp 5)) number of physical objects ranging in size from a few tens of meters to several hundred kilometers, orbiting not only in the traditional asteroid belt between Mars and Jupiter but also throughout the inner solar system. Many of the largest asteroids are classed into taxonomic groups based on their observed spectral properties and are designated as C, D. X, S or V types (as well as a wide range in sub-types). These objects are certainly the sources far the meteorites in our laboratories, but which asteroids are the sources for which meteorites? Spectral classes are nominally correlated to the chemical composition and physical characteristics of the asteroid itself based on studies of the spectral changes induced in meteorites due to exposure to a simulated space environment. While laboratory studies have produced some notable successes (e.g. the identification of the asteroid Vesta as the source of the H, E and D meteorite classes), it is unlikely that we have samples of each asteroidal spectral type in our meteorite collection. The correlation of spectral type and composition for many objects will therefore remain uncertain until we can return samples of specific asteroid types to Earth for analyses. The best candidates for sample return are asteroids that already come close to the Earth. Asteroids in orbit near 1 A.U. have been classified into three groups (Aten, Apollo & Amor) based on their orbital characteristics. These Near Earth Objects (NEOs) contain representatives of virtually all spectral types and sub-types of the asteroid population identified to date. Because of their close proximity to Earth, NEOs are prime targets for asteroid missions such as the NEAR-Shoemaker NASA Discovery Mission to Eros and the Japanese Hyabusa Mission to Itokawa. Also due to their close proximity to Earth, NEOs constitute the most likely set of celestial objects that will impact us in the relatively near future.
Derived from text
CHEMICAL ANALYSIS; CHEMICAL COMPOSITION; MINERALOGY; NEAR EARTH OBJECTS; METEORITES; ASTEROID MISSIONS
20090020402 NASA Dryden Flight Research Center, Edwards, CA, United States
Cyberinfrastructure for Airborne Sensor Webs
Freudinger, Lawrence C.; May 04, 2009; In English; 33rd International Symposium on Remote Sensing of Environment, 4-8 May 2009, stresa, Italy; Original contains color illustrations
Report No.(s): DFRC-927; No Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020402
Since 2004 the NASA Airborne Science Program has been prototyping and using infrastructure that enables researchers to interact with each other and with their instruments via network communications. This infrastructure uses satellite links and an evolving suite of applications and services that leverage open-source software. The use of these tools has increased near-real-time situational awareness during field operations, resulting in productivity improvements and the collection of better data. This paper describes the high-level system architecture and major components, with example highlights from the use of the infrastructure. The paper concludes with a discussion of ongoing efforts to transition to operational status.
Author
AIRBORNE EQUIPMENT; ARCHITECTURE (COMPUTERS); DATA LINKS; OPEN SOURCE LICENSING (COMPUTERS); SATELLITE NETWORKS; COMPUTER NETWORKS
20090020406 NASA Langley Research Center, Hampton, VA, United States
Stress Analysis of Bolted, Segmented Cylindrical Shells Exhibiting Flange Mating-Surface Waviness
Knight, Norman F., Jr.; Phillips, Dawn R.; Raju, Ivatury S.; May 04, 2009; In English; 50th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 4-7 May 2009, Palm Springs, CA, United States; Original contains color illustrations
Contract(s)/Grant(s): WBS 869021
Report No.(s): AIAA Paper 2009-2448; LF99-8509; Copyright; Avail.: CASI: A03, Hardcopy
Bolted, segmented cylindrical shells are a common structural component in many engineering systems especially for aerospace launch vehicles. Segmented shells are often needed due to limitations of manufacturing capabilities or transportation issues related to very long, large-diameter cylindrical shells. These cylindrical shells typically have a flange or ring welded to opposite ends so that shell segments can be mated together and bolted to form a larger structural system. As the diameter of these shells increases, maintaining strict fabrication tolerances for the flanges to be flat and parallel on a welded structure is an extreme challenge. Local fit-up stresses develop in the structure due to flange mating-surface mismatch (flange waviness). These local stresses need to be considered when predicting a critical initial flaw size. Flange waviness is one contributor to the fit-up stress state. The present paper describes the modeling and analysis effort to simulate fit-up stresses due to flange waviness in a typical bolted, segmented cylindrical shell. Results from parametric studies are presented for various flange mating-surface waviness distributions and amplitudes.
Author
CYLINDRICAL SHELLS; SEGMENTS; FLANGES; FABRICATION; FITTING; SURFACE DEFECTS; STRESS ANALYSIS; AEROSPACE ENGINEERING; WELDED STRUCTURES; DYNAMIC RESPONSE
20090020407 NASA Glenn Research Center, Cleveland, OH, United States
Phase Fluctuations at Goldstone Derived from 1-Year Site Testing Interferometer Data
Nessel, James A.; Acosta, Roberto J.; Morabito, David D.; April 2009; In English; Original contains color illustrations
Contract(s)/Grant(s): WBS 439432.04.12.01
Report No.(s): NASA/TM-2009-215600; E-16891; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020407
A two-element site test interferometer has been deployed at the NASA Deep Space Network (DSN) tracking complex in Goldstone, California, since May 2007. The interferometer system consists of two offset-fed 1.2 m parabolic reflectors which monitor atmospheric-induced amplitude and phase fluctuations on an unmodulated beacon signal (20.199 GHz) broadcast from a geostationary satellite (Anik F2). The geometry of the satellite and the ground-based infrastructure imposes a 48.5 elevation angle with a separation distance of 256 m along an east-west baseline. The interferometer has been recording phase fluctuation data, to date, for 1 yr with an overall system availability of 95 percent. In this paper, we provide the cumulative distribution functions (CDFs) for 1 year of recorded data, including phase rms, spatial structure function exponent, and surface meteorological measurements: surface wind speed, relative humidity, temperature, barometric pressure, and rain rate. Correlation between surface measurements, phase rms, and amplitude rms at different time scales are discussed. For 1 year, phase fluctuations at the DSN site in Goldstone, are better than 23 for 90 percent of the time (at 48.5 elevation). This data will be used to determine the suitability of the Goldstone site as a location for the Next Generation Deep Space Network.
Author
INTERFEROMETERS; DEEP SPACE NETWORK; ATMOSPHERIC PRESSURE; DISTRIBUTION FUNCTIONS; GEOSYNCHRONOUS ORBITS; WIND VELOCITY; SPACECRAFT TRACKING
20090020409 NASA Glenn Research Center, Cleveland, OH, United States
Analysis of Thermal and Reaction Times for Hydrogen Reduction of Lunar Regolith
Hegde, U.; Balasubramaniam, R.; Gokoglu, S.; April 2009; In English; Space Technology and Applications International Forum (STAIF-2008), 10-14 Feb. 2008, Albuquerque, NM, United States; Original contains black and white illustrations
Contract(s)/Grant(s): NCC3-975WBS 387498.04.01.04.03
Report No.(s): NASA/TM-2009-215623; E-16705-1; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020409
System analysis of oxygen production by hydrogen reduction of lunar regolith has shown the importance of the relative time scales for regolith heating and chemical reaction to overall performance. These values determine the sizing and power requirements of the system and also impact the number and operational phasing of reaction chambers. In this paper, a Nusselt number correlation analysis is performed to determine the heat transfer rates and regolith heat up times in a fluidized bed reactor heated by a central heating element (e.g., a resistively heated rod, or a solar concentrator heat pipe). A coupled chemical and transport model has also been developed for the chemical reduction of regolith by a continuous flow of hydrogen. The regolith conversion occurs on the surfaces of and within the regolith particles. Several important quantities are identified as a result of the above analyses. Reactor scale parameters include the void fraction (i.e., the fraction of the reactor volume not occupied by the regolith particles) and the residence time of hydrogen in the reactor. Particle scale quantities include the particle Reynolds number, the Archimedes number, and the time needed for hydrogen to diffuse into the pores of the regolith particles. The analysis is used to determine the heat up and reaction times and its application to NASA s oxygen production system modeling tool is noted.
Author
CHEMICAL REACTIONS; LUNAR ROCKS; REGOLITH; SOLAR COLLECTORS; CONTINUUM FLOW; HEAT TRANSFER; OXYGEN PRODUCTION
20090020410 NASA Langley Research Center, Hampton, VA, United States
A Continuum-Atomistic Analysis of Transgranular Crack Propagation in Aluminum
Yamakov, V.; Saether, E.; Glaessgen, E.; May 04, 2009; In English; 50th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 4-7 May 2009, Palm Springs, CA, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): NCC-1-02043WBS 698259.02.07.07.03.01
Report No.(s): LF99-8535; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020410
A concurrent multiscale modeling methodology that embeds a molecular dynamics (MD) region within a finite element (FEM) domain is used to study plastic processes at a crack tip in a single crystal of aluminum. The case of mode I loading is studied. A transition from deformation twinning to full dislocation emission from the crack tip is found when the crack plane is rotated around the [111] crystallographic axis. When the crack plane normal coincides with the [112] twinning direction, the crack propagates through a twinning mechanism. When the crack plane normal coincides with the [011] slip direction, the crack propagates through the emission of full dislocations. In intermediate orientations, a transition from full dislocation emission to twinning is found to occur with an increase in the stress intensity at the crack tip. This finding confirms the suggestion that the very high strain rates, inherently present in MD simulations, which produce higher stress intensities at the crack tip, over-predict the tendency for deformation twinning compared to experiments. The present study, therefore, aims to develop a more realistic and accurate predictive modeling of fracture processes.
Author
CRACK TIPS; ALUMINUM; CRACKS; CRACK PROPAGATION; STRESS INTENSITY FACTORS; PREDICTION ANALYSIS TECHNIQUES; MOLECULAR DYNAMICS; STRAIN RATE; CRYSTALLOGRAPHY; FRACTURING
20090020411 NASA Johnson Space Center, Houston, TX, United States
Identification of an Extremely 180-Rich Presolar Silicate Grain in Acfer 094
Nguyen, A. N.; Messenger, S.; [2009]; In English; 72nd Annual Meeting of the Meteorological Society, 13-18 Jul. 2009, Nancy, France
Report No.(s): JSC-CN-18342; Copyright; Avail.: CASI: A01, Hardcopy
Presolar silicate grains have been abundantly identified since their first discovery less than a decade ago [1,2,3]. The O isotopic compositions of both silicate and oxide stardust indicate the vast majority (>90%) condensed around Orich asymptotic giant branch (AGB) stars. Though both presolar phases have average sizes of ~300 nm, grains larger than 1 m are extremely uncommon for presolar silicates. Thus, while numerous isotopic systems have been measured in presolar oxide grains [4], very few isotopic analyses for presolar silicates exist outside of O and Si [2,5]. And still, these measurements suffer from isotopic dilution with surrounding matrix material [6]. We conduct a search for presolar silicates in the primitive carbonaceous chondrite Acfer 094 and in some cases obtain high spatial resolution, high precision isotopic ratios.
Author
SILICATES; CARBONACEOUS CHONDRITES; ASYMPTOTIC GIANT BRANCH STARS; MATRIX MATERIALS; STARDUST MISSION
20090020418 NASA Langley Research Center, Hampton, VA, United States
A Refined Zigzag Beam Theory for Composite and Sandwich Beams
Tessler, Alexander; Sciuva, Marco Di; Gherlone, Marco; Journal of Composite Materials; [2009]; vol. Volume 43; issue No. 9; pp. 1051-108; In English; Original contains black and white illustrations
Contract(s)/Grant(s): WBS: 984754.02.07.07.15.04
Report No.(s): LF99-8142; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://dx.doi.org/10.1177/0021998308097730
A new refined theory for laminated composite and sandwich beams that contains the kinematics of the Timoshenko Beam Theory as a proper baseline subset is presented. This variationally consistent theory is derived from the virtual work principle and employs a novel piecewise linear zigzag function that provides a more realistic representation of the deformation states of transverse-shear flexible beams than other similar theories. This new zigzag function is unique in that it vanishes at the top and bottom bounding surfaces of a beam. The formulation does not enforce continuity of the transverse shear stress across the beam s cross-section, yet is robust. Two major shortcomings that are inherent in the previous zigzag theories, shear-force inconsistency and difficulties in simulating clamped boundary conditions, and that have greatly limited the utility of these previous theories are discussed in detail. An approach that has successfully resolved these shortcomings is presented herein. Exact solutions for simply supported and cantilevered beams subjected to static loads are derived and the improved modelling capability of the new zigzag beam theory is demonstrated. In particular, extensive results for thick beams with highly heterogeneous material lay-ups are discussed and compared with corresponding results obtained from elasticity solutions, two other zigzag theories, and high-fidelity finite element analyses. Comparisons with the baseline Timoshenko Beam Theory are also presented. The comparisons clearly show the improved accuracy of the new, refined zigzag theory presented herein over similar existing theories. This new theory can be readily extended to plate and shell structures, and should be useful for obtaining relatively low-cost, accurate estimates of structural response needed to design an important class of high-performance aerospace structures.
Author
LAMINATES; COMPOSITE STRUCTURES; SANDWICH STRUCTURES; TIMOSHENKO BEAMS; KINEMATICS; DEFORMATION; EQUILIBRIUM
20090020419 NASA Langley Research Center, Hampton, VA, United States; Texas A&M Univ., Prairie View, TX, United States
Monte Carlo Analysis of Pion Contribution to Absorbed Dose from Galactic Cosmic Rays
Aghara, S.K.; Battnig, S.R.; Norbury, J.W.; Singleterry, R.C.; Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms; [2009]; vol. Volume 267; issue No. 7; pp. 1115-112; In English; Original contains color illustrations
Contract(s)/Grant(s): UNCFSP 003844WBS: 651549.02.07.01
Report No.(s): LF99-8099; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020419
http://dx.doi.org/10.1016/j.nimb.2009.01.136
Accurate knowledge of the physics of interaction, particle production and transport is necessary to estimate the radiation damage to equipment used on spacecraft and the biological effects of space radiation. For long duration astronaut missions, both on the International Space Station and the planned manned missions to Moon and Mars, the shielding strategy must include a comprehensive knowledge of the secondary radiation environment. The distribution of absorbed dose and dose equivalent is a function of the type, energy and population of these secondary products. Galactic cosmic rays (GCR) comprised of protons and heavier nuclei have energies from a few MeV per nucleon to the ZeV region, with the spectra reaching flux maxima in the hundreds of MeV range. Therefore, the MeV - GeV region is most important for space radiation. Coincidentally, the pion production energy threshold is about 280 MeV. The question naturally arises as to how important these particles are with respect to space radiation problems. The space radiation transport code, HZETRN (High charge (Z) and Energy TRaNsport), currently used by NASA, performs neutron, proton and heavy ion transport explicitly, but it does not take into account the production and transport of mesons, photons and leptons. In this paper, we present results from the Monte Carlo code MCNPX (Monte Carlo N-Particle eXtended), showing the effect of leptons and mesons when they are produced and transported in a GCR environment.
Author
EXTRATERRESTRIAL RADIATION; COSMIC RAYS; RADIATION DOSAGE; PIONS; LEPTONS; MESONS; PARTICLE PRODUCTION; RADIATION TRANSPORT; MONTE CARLO METHOD; RADIATION DAMAGE
20090020420 NASA Langley Research Center, Hampton, VA, United States
Fan Noise Prediction with Applications to Aircraft System Noise Assessment
Nark, Douglas M.; Envia, Edmane; Burley, Casey L.; May 11, 2009; In English; 15th AIAA/CEAS Aeroacoustics Conference, 11 - 13 May 2009, Florida, United States; Original contains color and black and white illustrations
Report No.(s): LF99-8034; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020420
This paper describes an assessment of current fan noise prediction tools by comparing measured and predicted sideline acoustic levels from a benchmark fan noise wind tunnel test. Specifically, an empirical method and newly developed coupled computational approach are utilized to predict aft fan noise for a benchmark test configuration. Comparisons with sideline noise measurements are performed to assess the relative merits of the two approaches. The study identifies issues entailed in coupling the source and propagation codes, as well as provides insight into the capabilities of the tools in predicting the fan noise source and subsequent propagation and radiation. In contrast to the empirical method, the new coupled computational approach provides the ability to investigate acoustic near-field effects. The potential benefits/costs of these new methods are also compared with the existing capabilities in a current aircraft noise system prediction tool. The knowledge gained in this work provides a basis for improved fan source specification in overall aircraft system noise studies.
Author
AIRCRAFT NOISE; FAN BLADES; NOISE PREDICTION; ACOUSTIC MEASUREMENT; COMPUTATIONAL FLUID DYNAMICS
20090020423 NASA Langley Research Center, Hampton, VA, United States
Total Cross Section Parameterizations for Pion Production in Nucleon-Nucleon Collisions
Norbury, John W.; Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms; [2008]; vol. Volume 267; issue Issue 7; pp. 1209-121; In English; Original contains color illustrations
Report No.(s): LF99-7720; No Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020423
http://dx.doi.org/10.1016/j.nimb.2009.02.067
Total cross section parameterizations for neutral and charged pion production in nucleon-nuelcon collisions are compared to an extensive set of experimental data over the projectile momentum range from threshold to 300 GeV. Both proton-proton and proton-neutron reactions are considered. Good agreement between parameterizations and experiment is found, and therefore the parameterizations will be useful for applications, such as transport codes.
Author
PARTICLE COLLISIONS; NUCLEON-NUCLEON INTERACTIONS; PIONS; PARTICLE PRODUCTION; ASTROPHYSICS
20090020425 NASA Langley Research Center, Hampton, VA, United States
A Finite Element Theory for Predicting the Attenuation of Extended-Reacting Liners
Watson, W. R.; Jones, M. G.; May 11, 2009; In English; 15th AIAA/CEAS Aeroacoustics Conference, 11-13 May 2009, Miami, FL, United States; Original contains color illustrations
Contract(s)/Grant(s): WBS 561581
Report No.(s): LF99-7833; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020425
A non-modal finite element theory for predicting the attenuation of an extended-reacting liner containing a porous facesheet and located in a no-flow duct is presented. The mathematical approach is to solve separate wave equations in the liner and duct airway and to couple these two solutions by invoking kinematic constraints at the facesheet that are consistent with a continuum theory of fluid motion. Given the liner intrinsic properties, a weak Galerkin finite element formulation with cubic polynomial basis functions is used as the basis for generating a discrete system of acoustic equations that are solved to obtain the coupled acoustic field. A state-of-the-art, asymmetric, parallel, sparse equation solver is implemented that allows tens of thousands of grid points to be analyzed. A grid refinement study is presented to show that the predicted attenuation converges. Excellent comparison of the numerically predicted attenuation to that of a mode theory (using a Haynes 25 metal foam liner) is used to validate the computational approach. Simulations are also presented for fifteen porous plate, extended-reacting liners. The construction of some of the porous plate liners suggest that they should behave as resonant liners while the construction of others suggest that they should behave as broadband attenuators. In each case the finite element theory is observed to predict the proper attenuation trend.
Author
DUCTS; WAVE EQUATIONS; ACOUSTICS; COMPUTATIONAL GRIDS; FINITE ELEMENT METHOD; KINEMATICS; LININGS
20090020430 NASA Langley Research Center, Hampton, VA, United States
Validation of an Acoustic Impedance Prediction Model for Skewed Resonators
Howerton, Brian M.; Parrott, Tony L.; May 11, 2009; In English; 15th AIAA/CEAS Aeroacoustics Conference, 11-13 May 2009, Miami, FL, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 561581.02.08.07.18.03
Report No.(s): AIAA Paper 2009-3143; LF99-7894; Copyright; Avail.: CASI: A03, Hardcopy
An impedance prediction model was validated experimentally to determine the composite impedance of a series of high-aspect ratio slot resonators incorporating channel skew and sharp bends. Such structures are useful for packaging acoustic liners into constrained spaces for turbofan noise control applications. A formulation of the Zwikker-Kosten Transmission Line (ZKTL) model, incorporating the Richards correction for rectangular channels, is used to calculate the composite normalized impedance of a series of six multi-slot resonator arrays with constant channel length. Experimentally, acoustic data was acquired in the NASA Langley Normal Incidence Tube over the frequency range of 500 to 3500 Hz at 120 and 140 dB OASPL. Normalized impedance was reduced using the Two-Microphone Method for the various combinations of channel skew and sharp 90o and 180o bends. Results show that the presence of skew and/or sharp bends does not significantly alter the impedance of a slot resonator as compared to a straight resonator of the same total channel length. ZKTL predicts the impedance of such resonators very well over the frequency range of interest. The model can be used to design arrays of slot resonators that can be packaged into complex geometries heretofore unsuitable for effective acoustic treatment.
Author
ACOUSTIC PROPERTIES; IMPEDANCE; MATHEMATICAL MODELS; RESONATORS; TRANSMISSION LINES; TURBOFANS; FREQUENCY RANGES
20090020432 Georgia Inst. of Tech., Atlanta, GA, United States; NASA Langley Research Center, Hampton, VA, United States
Test Plan for the Technology Maturation of Supersonic Inflatable Aerodynamic Decelerators
Kelly, Jenny R.; Cruz, Juan R.; May 04, 2009; In English; 20th AIAA Aerodynamic Decelerator Systems Technology Conference, 4-7 May 2009, Washington, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS: 984754.02.07.07.22.05
Report No.(s): AIAA Paper 2009-2969; LF99-8617; Copyright; Avail.: CASI: A03, Hardcopy
Supersonic inflatable aerodynamic decelerators (IADs) are drag devices intended to be deployed at high Mach numbers. In the application considered here they assist in the descent and landing of spacecraft on Mars. Although promising, present IAD technology is not yet sufficiently mature for use in the near future. This paper describes a technology maturation plan for tension cone IADs using subscale test articles to reduce development costs. As envisioned, the proposed test plan includes three phases: wind tunnel tests (subsonic), unpowered high-altitude flight tests (transonic), and powered high-altitude tests (supersonic). This test plan is based on a building block approach in which successful completion of each phase adds to the understanding of the behavior of IADs and reduces the risk of the subsequent, more expensive phases. By properly scaling the IADs, test articles of the same size and nearly the same construction can be used for all three phases. The final phase is a dynamically scaled flight test with IAD deployment at the same Mach number as the full-scale vehicle on Mars. Two full-scale example cases are presented: one for a single-stage system (15 m dia. IAD to subsonic retropropulsion), and another for a two-stage system (10.5 m dia. IAD to subsonic parachute). Using scale factors of 0.333 and 0.476 yield subscale test IADs of 5 m dia. The dynamically scaled powered flight test starts at Mach 4 and an altitude of 33.5 km. Existing balloons and rocket motors are shown to be adequate to meet the required test conditions.
Author
AERODYNAMIC BRAKES; INFLATABLE STRUCTURES; CONES; TECHNOLOGY ASSESSMENT; RESEARCH AND DEVELOPMENT; FLIGHT TESTS; HIGH ALTITUDE; SUPERSONIC WIND TUNNELS; WIND TUNNEL TESTS
20090020433 NASA Langley Research Center, Hampton, VA, United States; National Inst. of Aerospace, Hampton, VA, United States
Flight Dynamics of an Aeroshell Using an Attached Inflatable Aerodynamic Decelerator
Cruz, Juan R.; Schoenenberger, Mark; Axdahl, Erik; Wilhite, Alan; May 04, 2009; In English; 20th AIAA Aerodynamic Decelerator Systems Technology Conference, 4 - 7 May 2009, Washington, United States; Original contains black and white illustrations
Contract(s)/Grant(s): WBS: 984754.02.07.07.22.05
Report No.(s): AIAA Paper 2009-2963; LF99-8622; Copyright; Avail.: CASI: A03, Hardcopy
An aeroelastic analysis of the behavior of an entry vehicle utilizing an attached inflatable aerodynamic decelerator during supersonic flight is presented. The analysis consists of a planar, four degree of freedom simulation. The aeroshell and the IAD are assumed to be separate, rigid bodies connected with a spring-damper at an interface point constraining the relative motion of the two bodies. Aerodynamic forces and moments are modeled using modified Newtonian aerodynamics. The analysis includes the contribution of static aerodynamic forces and moments as well as pitch damping. Two cases are considered in the analysis: constant velocity flight and planar free flight. For the constant velocity and free flight cases with neutral pitch damping, configurations with highly-stiff interfaces exhibit statically stable but dynamically unstable aeroshell angle of attack. Moderately stiff interfaces exhibit static and dynamic stability of aeroshell angle of attack due to damping induced by the pitch angle rate lag between the aeroshell and IAD. For the free-flight case, low values of both the interface stiffness and damping cause divergence of the aeroshell angle of attack due to the offset of the IAD drag force with respect to the aeroshell center of mass. The presence of dynamic aerodynamic moments was found to influence the stability characteristics of the vehicle. The effect of gravity on the aeroshell angle of attack stability characteristics was determined to be negligible for the cases investigated.
Author
AEROSHELLS; AEROELASTICITY; AERODYNAMIC BRAKES; INFLATABLE STRUCTURES; SUPERSONIC FLIGHT
20090020434 NASA Johnson Space Center, Houston, TX, United States
Astronaut Thermal Exposure: Re-Entry After Low Earth Orbit Rescue Mission
Gillis, David B.; Hamilton, Douglas; Ilcus, Stana; Stepaniak, Phil; Son, Chang; Bue, Grant; May 06, 2009; In English; 80th Annual Scientific Meeting of the Aerospace Medical Association (AsMA), 3-7 May 2009, Los Angeles, CA, United States; Original contains color and black and white illustrations
Report No.(s): JSC-CN-18263; Copyright; Avail.: CASI: A03, Hardcopy
The STS-125 mission, launched May 11, 2009, is the final servicing mission to the Hubble Space Telescope. The repair mission's EVA tasks are described, including: installing a new wide field camera; installing the Cosmic Origins Spectrograph; repairing the Space Telescope Imaging Spectrograph; installing a new outer blanket layer; adding a Soft Capture and Rendezvous System for eventual controlled deorbit in about 2014; replacing the 'A' side Science Instrument Command and Data Handling module; repairing the Advanced Camera for surveys; and, replacing the rate sensor unit gyroscopes, fine guidance sensors and 3 batteries. Additionally, the Shuttle crew cabin thermal environment is described. A CFD model of per person CO2 demonstrates a discrepancy between crew breathing volume and general mid-deck levels of CO2. A follow-on CFD analysis of the mid-deck temperature distribution is provided. Procedural and engineering mitigation plans are presented to counteract thermal exposure upon reentry to the Earth atmosphere. Some of the procedures include: full cold soak the night prior to deorbit; modifying deck stowage to reduce interference with air flow; and early securing of avionics post-landing to reduce cabin thermal load prior to hatch opening. Engineering mitigation activities include modifying the location of the aft starboard ICUs, eliminating the X3 stack and eliminating ICU exhaust air directed onto astronauts; improved engineering data of ICU performance; and, verifying the adequacy of mid-deck temperature control using CFD models in addition to lumped parameter models. Post-mitigation CFD models of mid-deck temperature profiles and distribution are provided.
Derived from text
SPACE SHUTTLE MISSIONS; ORBITAL SERVICING; HUBBLE SPACE TELESCOPE; MANNED SPACECRAFT; SPACECRAFT REENTRY; RISK MANAGEMENT; THERMAL PROTECTION; TEMPERATURE CONTROL; AEROSPACE SAFETY; AEROSPACE ENGINEERING; SPACECRAFT DESIGN
20090020435 NASA Langley Research Center, Hampton, VA, United States
Measurements of the Flowfield Interaction Between Tandem Cylinders
Neuhart, Dan H.; Jenkins, Luther N.; Choudhari, Meelan M.; Khorrami, Mehdi R.; May 11, 2009; In English; 15th AIAA/CEAS Aeroacoustics Conference, 11-13 May 2009, Miami, FL, United States; Original contains color illustrations
Contract(s)/Grant(s): WBS 561581.02.08.07.18.02
Report No.(s): LF99-7906; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020435
This paper presents the most recent measurements from an ongoing investigation of the unsteady wake interference between a pair of circular cylinders in tandem. The purpose of this investigation is to help build an in-depth experimental database for this canonical flow configuration that embodies the effects of component interaction in landing gear noise. This new set of measurements augments the previous database at the primary Reynolds number (based on tunnel speed and cylinder diameter) of 1.66 105 in four important respects. First, better circumferential resolution of surface pressure fluctuations is obtained via cylinder "clocking". Second, higher resolution particle image velocimetry measurements of the shear layer separating from the cylinders are achieved. Third, the effects of simultaneous boundary layer trips along both the front and rear cylinders, versus front cylinder alone in the previous measurements, are studied. Lastly, on-surface and off-surface characteristics of unsteady flow near the "critical" cylinder spacing, wherein the flow switches intermittently between two states that are characteristic of lower and higher spacings, are examined. This critical spacing occurs in the middle of a relatively sudden change in the drag of either cylinder and is characterized by a loud intermittent noise and a flow behavior that randomly transitions between shear layer attachment to the rear cylinder and constant shedding and rollup in front of it. Analysis of this bistable flow state reveals much larger spanwise correlation lengths of surface pressure fluctuations than those at larger and smaller values of the cylinder spacing.
Author
FLOW DISTRIBUTION; UNSTEADY FLOW; SHEAR LAYERS; PRESSURE OSCILLATIONS; BOUNDARY LAYER CONTROL; AERODYNAMIC INTERFERENCE; REYNOLDS NUMBER
20090020436 NASA Langley Research Center, Hampton, VA, United States
A Computational and Experimental Study of Resonators in Three Dimensions
Tam, C. K. W.; Ju, H.; Jones, Michael G.; Watson, Willie R.; Parrott, Tony L.; May 11, 2009; In English; 15th AIAA/CEAS Aeroacoustics Conference, 11-13 May 2009, Miami, FL, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): NNL04AA01AWBS 561581.02.08.07
Report No.(s): AIAA Paper 2009-3171; LF99-7949; Copyright; Avail.: CASI: A03, Hardcopy
In a previous work by the present authors, a computational and experimental investigation of the acoustic properties of two-dimensional slit resonators was carried out. The present paper reports the results of a study extending the previous work to three dimensions. This investigation has two basic objectives. The first is to validate the computed results from direct numerical simulations of the flow and acoustic fields of slit resonators in three dimensions by comparing with experimental measurements in a normal incidence impedance tube. The second objective is to study the flow physics of resonant liners responsible for sound wave dissipation. Extensive comparisons are provided between computed and measured acoustic liner properties with both discrete frequency and broadband sound sources. Good agreements are found over a wide range of frequencies and sound pressure levels. Direct numerical simulation confirms the previous finding in two dimensions that vortex shedding is the dominant dissipation mechanism at high sound pressure intensity. However, it is observed that the behavior of the shed vortices in three dimensions is quite different from those of two dimensions. In three dimensions, the shed vortices tend to evolve into ring (circular in plan form) vortices, even though the slit resonator opening from which the vortices are shed has an aspect ratio of 2.5. Under the excitation of discrete frequency sound, the shed vortices align themselves into two regularly spaced vortex trains moving away from the resonator opening in opposite directions. This is different from the chaotic shedding of vortices found in two-dimensional simulations. The effect of slit aspect ratio at a fixed porosity is briefly studied. For the range of liners considered in this investigation, it is found that the absorption coefficient of a liner increases when the open area of the single slit is subdivided into multiple, smaller slits.
Author
SLITS; RESONATORS; TWO DIMENSIONAL MODELS; ACOUSTIC PROPERTIES; FLOW DISTRIBUTION; HIGH PRESSURE; SOUND WAVES; VORTEX SHEDDING; IMPEDANCE
20090020437 NASA Langley Research Center, Hampton, VA, United States
Noise Radiation From a Leading-Edge Slat
Lockhard, David P.; Choudhari, Meelan M.; May 11, 2009; In English; 15th AIAA/CEAS Aeroacoustics Conference, 11-13 May 2009, Miami, FL, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 561581.02.08.07.18.03
Report No.(s): AIAA Paper 2009-3101; LF99-7973; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020437
This paper extends our previous computations of unsteady flow within the slat cove region of a multi-element high-lift airfoil configuration, which showed that both statistical and structural aspects of the experimentally observed unsteady flow behavior can be captured via 3D simulations over a computational domain of narrow spanwise extent. Although such narrow domain simulation can account for the spanwise decorrelation of the slat cove fluctuations, the resulting database cannot be applied towards acoustic predictions of the slat without invoking additional approximations to synthesize the fluctuation field over the rest of the span. This deficiency is partially alleviated in the present work by increasing the spanwise extent of the computational domain from 37.3% of the slat chord to nearly 226% (i.e., 15% of the model span). The simulation database is used to verify consistency with previous computational results and, then, to develop predictions of the far-field noise radiation in conjunction with a frequency-domain Ffowcs-Williams Hawkings solver.
Author
AIRFOILS; LEADING EDGES; UNSTEADY FLOW; AERODYNAMIC CONFIGURATIONS; SOUND WAVES
20090020438 NASA Langley Research Center, Hampton, VA, United States
Assessment of Soft Vane and Metal Foam Engine Noise Reduction Concepts
Jones, Michael G.; Parrott, Tony L.; Sutliff, Daniel L.; Hughes, Chris; May 11, 2009; In English; 15th AIAA/CEAS Aeroacoustics Conference, 11-13 May 2009, Miami, FL, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 561581.02.08.07
Report No.(s): AIAA Paper 2009-3142; LF99-8002; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020438
Two innovative fan-noise reduction concepts developed by NASA are presented - soft vanes and over-the-rotor metal foam liners. Design methodologies are described for each concept. Soft vanes are outlet guide vanes with internal, resonant chambers that communicate with the exterior aeroacoustic environment via a porous surface. They provide acoustic absorption via viscous losses generated by interaction of unsteady flows with the internal solid structure. Over-the-rotor metal foam liners installed at or near the fan rotor axial plane provide rotor noise absorption. Both concepts also provide pressure-release surfaces that potentially inhibit noise generation. Several configurations for both concepts are evaluated with a normal incidence tube, and the results are used to guide designs for implementation in two NASA fan rigs. For soft vanes, approximately 1 to 2 dB of broadband inlet and aft-radiated fan noise reduction is achieved. For over-the-rotor metal foam liners, up to 3 dB of fan noise reduction is measured in the low-speed fan rig, but minimal reduction is measured in the high-speed fan rig. These metal foam liner results are compared with a static engine test, in which inlet sound power level reductions up to 5 dB were measured. Brief plans for further development are also provided.
Author
ACOUSTIC ATTENUATION; AERODYNAMIC NOISE; AEROACOUSTICS; UNSTEADY FLOW; ROTOR AERODYNAMICS; NOISE REDUCTION; METAL FOAMS; GUIDE VANES; ENGINE NOISE; ABSORPTIVITY
20090020439 NASA Langley Research Center, Hampton, VA, United States
A Comparison Study of Normal-Incidence Acoustic Impedance Measurements of a Perforate Liner
Schultz, Todd; Liu, Fei; Cattafesta, Louis; Sheplak, Mark; Jones, Michael; May 11, 2009; In English; 15th AIAA/CEAS Aeroacoustics Conference, 11-13 May 2009, Miami, FL, United States
Contract(s)/Grant(s): WBS 561581.02.08.07
Report No.(s): AIAA Paper 2009-3142; LF99-8019; Copyright; Avail.: CASI: A03, Hardcopy
The eduction of the acoustic impedance for liner configurations is fundamental to the reduction of noise from modern jet engines. Ultimately, this property must be measured accurately for use in analytical and numerical propagation models of aircraft engine noise. Thus any standardized measurement techniques must be validated by providing reliable and consistent results for different facilities and sample sizes. This paper compares normal-incidence acoustic impedance measurements using the two-microphone method of ten nominally identical individual liner samples from two facilities, namely 50.8 mm and 25.4 mm square waveguides at NASA Langley Research Center and the University of Florida, respectively. The liner chosen for this investigation is a simple single-degree-of-freedom perforate liner with resonance and anti-resonance frequencies near 1.1 kHz and 2.2 kHz, respectively. The results show that the ten measurements have the most variation around the anti-resonance frequency, where statistically significant differences exist between the averaged results from the two facilities. However, the sample-to-sample variation is comparable in magnitude to the predicted cross-sectional area-dependent cavity dissipation differences between facilities, providing evidence that the size of the present samples does not significantly influence the results away from anti-resonance.
Author
ACOUSTIC IMPEDANCE; IMPEDANCE MEASUREMENT; RESONANT FREQUENCIES; LININGS; NOISE PROPAGATION; WAVEGUIDES; AIRCRAFT MODELS; DEGREES OF FREEDOM; ENGINE NOISE
20090020444 NASA Marshall Space Flight Center, Huntsville, AL, United States
Interstellar Propulsion Research: Realistic Possibilities and Idealistic Dreams
Johnson, Les; February 24, 2009; In English; Space, Propulsion and Energy Sciences International Forum (SPESIF-2009), 24-26 Feb. 2009, Huntsville, AL, United States
Report No.(s): M09-0305; No Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020444
Though physically possible, interstellar travel will be exceedingly difficult. Both the known laws of physics and the limits of our current understanding of engineering place extreme limits on what may actually be possible. Our remote ancestors looked at the night sky and assumed those tiny points of light were campfires around which other tribes were gathered -- and they dreamed of someday making the trip to visit them. In our modern era, we've grown accustomed to humans regularly traveling into space and our robots voyaging ever-deeper into the outer edges of our solar system. Traveling to those distant campfires (stars) has been made to look easy by the likes of Captains Kirk and Picard as well as Han Solo and Commander Adama. Our understanding of physics and engineering has not kept up with our imaginations and many are becoming frustrated with the current pace at which we are exploring the universe. Fortunately, there are ideas that may one day lead to new physical theories about how the universe works and thus potentially make rapid interstellar travel possible -- but many of these are just ideas and are not even close to being considered a scientific theory or hypothesis. Absent any scientific breakthroughs, we should not give up hope. Nature does allow for interstellar travel, albeit slowly and requiring an engineering capability far beyond what we now possess. Antimatter, fusion and photon sail propulsion are all candidates for relatively near-term interstellar missions. The plenary lecture will discuss the dreams and challenges of interstellar travel, our current understanding of what may be possible and some of the "out of the box" ideas that may allow us to become an interstellar species someday in the future.
Author
INTERSTELLAR TRAVEL; SPACECRAFT PROPULSION; MATTER-ANTIMATTER PROPULSION; FUSION PROPULSION
20090020451 NASA Langley Research Center, Hampton, VA, United States; Florida Univ., Gainesville, FL, United States
A Comparative Study of a 1/4-Scale Gulfstream G550 Aircraft Nose Gear Model
Khorrami, Mehdi R.; Neuhart, Dan H.; Zawodny, Nikolas S.; Liu, Fei; Yardibi, Tarik; Cattafesta, Louis; Van de Ven, Thomas; May 11, 2009; In English; 15th AIAA/CEAS Aeroacoustics Conference, 11 - 13 May 2009, Florida, United States; Original contains color and black and white illustrations
Report No.(s): LF99-7993; Copyright; Avail.: CASI: A03, Hardcopy
A series of fluid dynamic and aeroacoustic wind tunnel experiments are performed at the University of Florida Aeroacoustic Flow Facility and the NASA-Langley Basic Aerodynamic Research Tunnel Facility on a high-fidelity -scale model of Gulfstream G550 aircraft nose gear. The primary objectives of this study are to obtain a comprehensive aeroacoustic dataset for a nose landing gear and to provide a clearer understanding of landing gear contributions to overall airframe noise of commercial aircraft during landing configurations. Data measurement and analysis consist of mean and fluctuating model surface pressure, noise source localization maps using a large-aperture microphone directional array, and the determination of far field noise level spectra using a linear array of free field microphones. A total of 24 test runs are performed, consisting of four model assembly configurations, each of which is subjected to three test section speeds, in two different test section orientations. The different model assembly configurations vary in complexity from a fully-dressed to a partially-dressed geometry. The two model orientations provide flyover and sideline views from the perspective of a phased acoustic array for noise source localization via beamforming. Results show that the torque arm section of the model exhibits the highest rms pressures for all model configurations, which is also evidenced in the sideline view noise source maps for the partially-dressed model geometries. Analysis of acoustic spectra data from the linear array microphones shows a slight decrease in sound pressure levels at mid to high frequencies for the partially-dressed cavity open model configuration. In addition, far field sound pressure level spectra scale approximately with the 6th power of velocity and do not exhibit traditional Strouhal number scaling behavior.
Author
AERODYNAMIC CONFIGURATIONS; AIRCRAFT MODELS; AEROACOUSTICS; LANDING GEAR; AERODYNAMIC NOISE; SPECTRUM ANALYSIS; NOISE GENERATORS
20090020452 NASA Langley Research Center, Hampton, VA, United States
Impedance Eduction in Ducts with Higher-Order Modes and Flow
Watson, Willie R.; Jones, Michael G.; May 11, 2009; In English; 15th AIAA/CEAS Aeroacoustics Conference, 11-13 May 2009, Miami, FL, United States; Original contains color illustrations
Contract(s)/Grant(s): WBS 561581
Report No.(s): LF99-7999; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020452
An impedance eduction technique, previously validated for ducts with plane waves at the source and duct termination planes, has been extended to support higher-order modes at these locations. Inputs for this method are the acoustic pressures along the source and duct termination planes, and along a microphone array located in a wall either adjacent or opposite to the test liner. A second impedance eduction technique is then presented that eliminates the need for the microphone array. The integrity of both methods is tested using three sound sources, six Mach numbers, and six selected frequencies. Results are presented for both a hardwall and a test liner (with known impedance) consisting of a perforated plate bonded to a honeycomb core. The primary conclusion of the study is that the second method performs well in the presence of higher-order modes and flow. However, the first method performs poorly when most of the microphones are located near acoustic pressure nulls. The negative effects of the acoustic pressure nulls can be mitigated by a judicious choice of the mode structure in the sound source. The paper closes by using the first impedance eduction method to design a rectangular array of 32 microphones for accurate impedance eduction in the NASA LaRC Curved Duct Test Rig in the presence of expected measurement uncertainties, higher order modes, and mean flow.
Author
DUCTS; IMPEDANCE; SOUND PRESSURE; PLANE WAVES; MACH NUMBER
20090020454 NASA Glenn Research Center, Cleveland, OH, United States; NASA Langley Research Center, Hampton, VA, United States
An Analytical Assessment of NASA's N+1 Subsonic Fixed Wing Project Noise Goal
Berton, Jeffrey J.; Envia, Edmane; Burley, Casey L.; May 11, 2009; In English; 15th AIAA/CEAS Aeroacoustics Conference, 11 - 13 May 2009, Florida, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS: 561581.02.08.07.18.03
Report No.(s): LF99-8609; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020454
The Subsonic Fixed Wing Project of NASA's Fundamental Aeronautics Program has adopted a noise reduction goal for new, subsonic, single-aisle, civil aircraft expected to replace current 737 and A320 airplanes. These so-called 'N+1' aircraft - designated in NASA vernacular as such since they will follow the current, in-service, 'N' airplanes - are hoped to achieve certification noise goal levels of 32 cumulative EPNdB under current Stage 4 noise regulations. A notional, N+1, single-aisle, twinjet transport with ultrahigh bypass ratio turbofan engines is analyzed in this study using NASA software and methods. Several advanced noise-reduction technologies are analytically applied to the propulsion system and airframe. Certification noise levels are predicted and compared with the NASA goal.
Author
NOISE REDUCTION; AIRCRAFT ENGINES; TURBOFAN ENGINES; SUBSONIC AIRCRAFT; ENGINE DESIGN; AIRCRAFT PERFORMANCE; AEROSPACE ENGINEERING; AEROACOUSTICS
20090020455 NASA Langley Research Center, Hampton, VA, United States
Advanced Computational and Experimental Techniques for Nacelle Liner Performance Evaluation
Gerhold, Carl H.; Jones, Michael G.; Brown, Martha C.; Nark, Douglas; May 11, 2009; In English; 15th AIAA/CEAS Aeroacoustics Conference, 11 - 13 May 2009, Florida, United States; Original contains color illustrations
Contract(s)/Grant(s): WBS: 561581.02.08.07.18.03
Report No.(s): LF99-8654; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020455
The Curved Duct Test Rig (CDTR) has been developed to investigate sound propagation through a duct of size comparable to the aft bypass duct of typical aircraft engines. The axial dimension of the bypass duct is often curved and this geometric characteristic is captured in the CDTR. The semiannular bypass duct is simulated by a rectangular test section in which the height corresponds to the circumferential dimension and the width corresponds to the radial dimension. The liner samples are perforate over honeycomb core and are installed on the side walls of the test section. The top and bottom surfaces of the test section are acoustically rigid to simulate a hard wall bifurcation or pylon. A unique feature of the CDTR is the control system that generates sound incident on the liner test section in specific modes. Uniform air flow, at ambient temperature and flow speed Mach 0.275, is introduced through the duct. Experiments to investigate configuration effects such as curvature along the flow path on the acoustic performance of a sample liner are performed in the CDTR and reported in this paper. Combinations of treated and acoustically rigid side walls are investigated. The scattering of modes of the incident wave, both by the curvature and by the asymmetry of wall treatment, is demonstrated in the experimental results. The effect that mode scattering has on total acoustic effectiveness of the liner treatment is also shown. Comparisons of measured liner attenuation with numerical results predicted by an analytic model based on the parabolic approximation to the convected Helmholtz equation are reported. The spectra of attenuation produced by the analytic model are similar to experimental results for both walls treated, straight and curved flow path, with plane wave and higher order modes incident. The numerical model is used to define the optimized resistance and reactance of a liner that significantly improves liner attenuation in the frequency range 1900-2400 Hz. A liner impedance descriptor is used to determine the liner parameters that achieve the optimum impedance.
Author
NACELLES; SOUND PROPAGATION; LININGS; DUCTS; AIRCRAFT ENGINES; BYPASS RATIO; NOISE REDUCTION; ACOUSTIC ATTENUATION; ACOUSTIC PROPERTIES; COMPUTATIONAL AEROACOUSTICS
Additions to the NASA Aeronautics and Space Database as of 06/05/2009
20090020460 NASA Johnson Space Center, Houston, TX, United States
Human-Centered Design Capability
Fitts, David J.; Howard, Robert; May 05, 2009; In English; Aerospace Medical Association Annual Meeting, 3-7 May 2009, Boston, MA, United States; Original contains color illustrations
Report No.(s): JSC-CN-18281; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020460
For NASA, human-centered design (HCD) seeks opportunities to mitigate the challenges of living and working in space in order to enhance human productivity and well-being. Direct design participation during the development stage is difficult, however, during project formulation, a HCD approach can lead to better more cost-effective products. HCD can also help a program enter the development stage with a clear vision for product acquisition. HCD tools for clarifying design intent are listed. To infuse HCD into the spaceflight lifecycle the Space and Life Sciences Directorate developed the Habitability Design Center. The Center has collaborated successfully with program and project design teams and with JSC's Engineering Directorate. This presentation discusses HCD capabilities and depicts the Center's design examples and capabilities.
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HUMAN FACTORS ENGINEERING; AEROSPACE ENVIRONMENTS; AEROSPACE ENGINEERING; SPACE HABITATS; DESIGN OPTIMIZATION
20090020461 NASA Goddard Space Flight Center, Greenbelt, MD, United States
A Semiclassical Derivation of the QCD Coupling
Batchelor, David; March 17, 2009; In English; Original contains black and white illustrations
No Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020461
The measured value of the QCD coupling alpha(sub s) at the energy M(sub Zo), the variation of alpha(sub s) as a function of energy in QCD, and classical relativistic dynamics are used to investigate virtual pairs of quarks and antiquarks in vacuum fluctuations. For virtual pairs of bottom quarks and antiquarks, the pair lifetime in the classical model agrees with the lifetime from quantum mechanics to good approximation, and the action integral in the classical model agrees as well with the action that follows from the Uncertainty Principle. This suggests that the particles might have small de Broglie wavelengths and behave with well-localized pointlike dynamics. It also permits alpha(sub s) at the mass energy twice the bottom quark mass to be expressed as a simple fraction: 3/16. This is accurate to approximately 10%. The model in this paper predicts the measured value of alpha(sub s)(M(sub Zo)) to be 0.121, which is in agreement with recent measurements within statistical uncertainties.
Author
QUANTUM CHROMODYNAMICS; QUANTUM MECHANICS
20090020462 NASA Goddard Space Flight Center, Greenbelt, MD, United States
Probability of Detection Demonstration Transferability
Parker, Bradford H.; November 2008; In English
No Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020462
The ongoing Mars Science Laboratory (MSL) Propellant Tank Penetrant Nondestructive Evaluation (NDE) Probability of Detection (POD) Assessment (NESC activity) has surfaced several issues associated with liquid penetrant POD demonstration testing. This presentation lists factors that may influence the transferability of POD demonstration tests. Initial testing will address the liquid penetrant inspection technique. Some of the factors to be considered in this task are crack aspect ratio, the extent of the crack opening, the material and the distance between the inspection surface and the inspector's eye.
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FAULT DETECTION; PROPELLANT TANKS; CRACKS; NONDESTRUCTIVE TESTS
20090020463 MEI Technologies, Inc., Seabrook, MD, United States
Total Dose Effects on Single Event Transients in Digital CMOS and Linear Bipolar Circuits
Buchner, S.; McMorrow, D.; Sibley, M.; Eaton, P.; Mavis, D.; Dusseau, L.; Roche, N. J-H.; Bernard, M.; April 20, 2009; In English; Single Event Effects Symposium, 20-22 Apr. 2009, La Jolla, CA, United States; Original contains color and black and white illustrations
Copyright; Avail.: CASI: A03, Hardcopy
This presentation discusses the effects of ionizing radiation on single event transients (SETs) in circuits. The exposure of integrated circuits to ionizing radiation changes electrical parameters. The total ionizing dose effect is observed in both complementary metal-oxide-semiconductor (CMOS) and bipolar circuits. In bipolar circuits, transistors exhibit grain degradation, while in CMOS circuits, transistors exhibit threshold voltage shifts. Changes in electrical parameters can cause changes in single event upset(SEU)/SET rates. Depending on the effect, the rates may increase or decrease. Therefore, measures taken for SEU/SET mitigation might work at the beginning of a mission but not at the end following TID exposure. The effect of TID on SET rates should be considered if SETs cannot be tolerated.
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IONIZING RADIATION; LINEAR CIRCUITS; RADIATION DOSAGE; RADIATION EFFECTS; SINGLE EVENT UPSETS; ELECTRICAL PROPERTIES; INTEGRATED CIRCUITS; CMOS; SPACECRAFT ELECTRONIC EQUIPMENT; ASTRIONICS
20090020465 NASA Johnson Space Center, Houston, TX, United States
Stardust Abundance Variations among Interplanetary Dust Particles
Messenger, S.; Keller, L. P.; Nakamura-Messenger, K.; Nguyen, A. N.; Walker, Robert M.; [2009]; In English; 72nd Annual Meeting of the Meteoritical Society, 13-18 Jul. 2009, Nancy, France
Report No.(s): JSC-CN-18338; Copyright; Avail.: CASI: A01, Hardcopy
Presolar grain abundances reflect the degree of processing primitive materials have experienced. This is evidenced by the wide range of silicate stardust abundances among primitive meteorites (~10 to 300 ppm) [1], attributable to parent body hydrothermal processing. Stardust abundance variations are also pronounced in anhydrous interplanetary dust particles (CPIDPs), that have not experienced parent body processing (300 to > 10,000 ppm) [2-4]. The large range in stardust abundances among CP IDPs thus reflect nebular processing. Here we present results of a systematic search for stardust among cluster CP IDPs. Our goals are to establish mineralogical trends among IDPs with different stardust abundances. This may shed light into the nature of isotopically normal presolar grains (GEMS grains?; 5) if their abundances vary similarly to that of isotopically exotic stardust grains.
Author
INTERPLANETARY DUST; STARDUST MISSION; MINERALOGY; ABUNDANCE; METEORITES
20090020467 NASA, Washington, DC, United States
NASA Tech Briefs, March 2008
March 2008; In English; Original contains color and black and white illustrations
Copyright; Avail.: CASI: A03, Hardcopy
Topics covered include: WRATS Integrated Data Acquisition System; Breadboard Signal Processor for Arraying DSN Antennas; Digital Receiver Phase Meter; Split-Block Waveguide Polarization Twist for 220 to 325 GHz; Nano-Multiplication-Region Avalanche Photodiodes and Arrays; Tailored Asymmetry for Enhanced Coupling to WGM Resonators; Disabling CNT Electronic Devices by Use of Electron Beams; Conical Bearingless Motor/Generators; Integrated Force Method for Indeterminate Structures; Carbon-Nanotube-Based Electrodes for Biomedical Applications; Compact Directional Microwave Antenna for Localized Heating; Using Hyperspectral Imagery to Identify Turfgrass Stresses; Shaping Diffraction-Grating Grooves to Optimize Efficiency; Low-Light-Shift Cesium Fountain without Mechanical Shutters; Magnetic Compensation for Second-Order Doppler Shift in LITS; Nanostructures Exploit Hybrid-Polariton Resonances; Microfluidics, Chromatography, and Atomic-Force Microscopy; Model of Image Artifacts from Dust Particles; Pattern-Recognition System for Approaching a Known Target; Orchestrator Telemetry Processing Pipeline; Scheme for Quantum Computing Immune to Decoherence; Spin-Stabilized Microsatellites with Solar Concentrators; Phase Calibration of Antenna Arrays Aimed at Spacecraft; Ring Bus Architecture for a Solid-State Recorder; and Image Compression Algorithm Altered to Improve Stereo Ranging.
Author
NASA PROGRAMS; ANTENNA ARRAYS; ATOMIC FORCE MICROSCOPY; BREADBOARD MODELS; CARBON NANOTUBES; CHROMATOGRAPHY; DATA ACQUISITION; DOPPLER EFFECT; MICROWAVE ANTENNAS; NANOSTRUCTURES (DEVICES)
20090020468 California Inst. of Tech., Pasadena, CA, United States
Spin-Stabilized Microsatellites with Solar Concentrators
Timmerman, Paul; Shields, Virgil; NASA Tech Briefs, March 2008; March 2008; pp. 3; In English
Report No.(s): NPO-43055; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2670
A document proposes the development of spin-stabilized microsatellites powered by solar photovoltaic cells aided by solar concentrators. Each such satellite would have a cylindrical or other axisymmetric main body with solar cells mounted in a circumferential belt-like array on its exterior surface. The solar concentrator would be a halo-like outrigger cylindrical Fresnel lens array that would be deployed from and would surround the main body, connected to the main body via spokes or similar structural members. The spacecraft would be oriented with its axis of symmetry perpendicular to the line of sight to the Sun and would be set into rotation about this axis. In effect, the solar cells and concentrator would be oriented and rotated in a "rotisserie" mode, making it possible to take advantage of the concentration of solar light while preventing localized overheating of the solar cells. In addition, the mechanical stabilization inherently afforded by the rotation could be exploited as a means of passive attitude control or, at least, of reducing the requirement for active attitude control.
Author
SOLAR COLLECTORS; MICROSATELLITES; SOLAR CELLS; PHOTOVOLTAIC CELLS; ATTITUDE CONTROL; ACTIVE CONTROL; LINE OF SIGHT
20090020469 California Inst. of Tech., Pasadena, CA, United States
Model of Image Artifacts from Dust Particles
Willson, Reg; NASA Tech Briefs, March 2008; March 2008; pp. 26-2; In English; Original contains color and black and white illustrations
Report No.(s): NPO-42437; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2664
A mathematical model of image artifacts produced by dust particles on lenses has been derived. Machine-vision systems often have to work with camera lenses that become dusty during use. Dust particles on the front surface of a lens produce image artifacts that can potentially affect the performance of a machine-vision algorithm. The present model satisfies a need for a means of synthesizing dust image artifacts for testing machine-vision algorithms for robustness (or the lack thereof) in the presence of dust on lenses. A dust particle can absorb light or scatter light out of some pixels, thereby giving rise to a dark dust artifact. It can also scatter light into other pixels, thereby giving rise to a bright dust artifact. For the sake of simplicity, this model deals only with dark dust artifacts. The model effectively represents dark dust artifacts as an attenuation image consisting of an array of diffuse darkened spots centered at image locations corresponding to the locations of dust particles. The dust artifacts are computationally incorporated into a given test image by simply multiplying the brightness value of each pixel by a transmission factor that incorporates the factor of attenuation, by dust particles, of the light incident on that pixel. With respect to computation of the attenuation and transmission factors, the model is based on a first-order geometric (ray)-optics treatment of the shadows cast by dust particles on the image detector. In this model, the light collected by a pixel is deemed to be confined to a pair of cones defined by the location of the pixel s image in object space, the entrance pupil of the lens, and the location of the pixel in the image plane (see Figure 1). For simplicity, it is assumed that the size of a dust particle is somewhat less than the diameter, at the front surface of the lens, of any collection cone containing all or part of that dust particle. Under this assumption, the shape of any individual dust particle artifact is the shape (typically, circular) of the aperture, and the contribution of the particle to the attenuation factor for a given pixel is the fraction of the cross-sectional area of the collection cone occupied by the particle. Assuming that dust particles do not overlap, the net transmission factor for a given pixel is calculated as one minus the sum of attenuation factors contributed by all dust particles affecting that pixel. In a test, the model was used to synthesize attenuation images for random distributions of dust particles on the front surface of a lens at various relative aperture (F-number) settings. As shown in Figure 2, the attenuation images resembled dust artifacts in real test images recorded while the lens was aimed at a white target.
Author
COMPUTER VISION; MATHEMATICAL MODELS; GEOMETRICAL OPTICS; DUST; PIXELS; STATISTICAL DISTRIBUTIONS
20090020470 NASA Ames Research Center, Moffett Field, CA, United States
Carbon-Nanotube-Based Electrodes for Biomedical Applications
Li, Jun; Meyyappan, M.; NASA Tech Briefs, March 2008; March 2008; pp. 17-1; In English; Original contains color illustrations
Report No.(s): ARC-15061-1; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2659
A nanotube array based on vertically aligned nanotubes or carbon nanofibers has been invented for use in localized electrical stimulation and recording of electrical responses in selected regions of an animal body, especially including the brain. There are numerous established, emerging, and potential applications for localized electrical stimulation and/or recording, including treatment of Parkinson s disease, Tourette s syndrome, and chronic pain, and research on electrochemical effects involved in neurotransmission. Carbon-nanotube-based electrodes offer potential advantages over metal macroelectrodes (having diameters of the order of a millimeter) and microelectrodes (having various diameters ranging down to tens of microns) heretofore used in such applications. These advantages include the following: a) Stimuli and responses could be localized at finer scales of spatial and temporal resolution, which is at subcellular level, with fewer disturbances to, and less interference from, adjacent regions. b) There would be less risk of hemorrhage on implantation because nano-electrode-based probe tips could be configured to be less traumatic. c) Being more biocompatible than are metal electrodes, carbon-nanotube-based electrodes and arrays would be more suitable for long-term or permanent implantation. d) Unlike macro- and microelectrodes, a nano-electrode could penetrate a cell membrane with minimal disruption. Thus, for example, a nanoelectrode could be used to generate an action potential inside a neuron or in proximity of an active neuron zone. Such stimulation may be much more effective than is extra- or intracellular stimulation via a macro- or microelectrode. e) The large surface area of an array at a micron-scale footprint of non-insulated nanoelectrodes coated with a suitable electrochemically active material containing redox ingredients would make it possible to obtain a pseudocapacitance large enough to dissipate a relatively large amount of electric charge, so that a large stimulation current could be applied at a micron-scale region without exhausting the redox ingredients. f) Carbon nanotube array is more compatible with the three-dimensional network of tissues. Particularly, a better electrical-neural interface can be formed. g) A carbon nanotube array inlaid in insulating materials with only the ends exposed is an extremely sensitive electro-analysis tool that can measure the local neurotransmitter signal at extremely high sensitivity and temporal resolution.
Author
CARBON NANOTUBES; ELECTRODES; MILLIMETER WAVES; CELLS (BIOLOGY); CYTOLOGY; ELECTRIC CHARGE; OXIDATION-REDUCTION REACTIONS; TEMPORAL RESOLUTION; SPATIAL RESOLUTION
20090020471 NASA Glenn Research Center, Cleveland, OH, United States
Integrated Force Method for Indeterminate Structures
Hopkins, Dale A.; Halford, Gary R.; Patnaik, Surya N.; NASA Tech Briefs, March 2008; March 2008; pp. 14-1; In English; Original contains color illustrations
Report No.(s): LEW-17883-1; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2657
Two methods of solving indeterminate structural-mechanics problems have been developed as products of research on the theory of strain compatibility. In these methods, stresses are considered to be the primary unknowns (in contrast to strains and displacements being considered as the primary unknowns in some prior methods). One of these methods, denoted the integrated force method (IFM), makes it possible to compute stresses, strains, and displacements with high fidelity by use of modest finite-element models that entail relatively small amounts of computation. The other method, denoted the completed Beltrami Mitchell formulation (CBMF), enables direct determination of stresses in an elastic continuum with general boundary conditions, without the need to first calculate displacements as in traditional methods. The equilibrium equation, the compatibility condition, and the material law are the three fundamental concepts of the theory of structures. For almost 150 years, it has been commonly supposed that the theory is complete. However, until now, the understanding of the compatibility condition remained incomplete, and the compatibility condition was confused with the continuity condition. Furthermore, the compatibility condition as applied to structures in its previous incomplete form was inconsistent with the strain formulation in elasticity.
Author
STRUCTURAL ANALYSIS; COMPUTATION; ELASTIC PROPERTIES; EQUILIBRIUM EQUATIONS; STRESS ANALYSIS; FINITE ELEMENT METHOD; BOUNDARY CONDITIONS
20090020472 California Inst. of Tech., Pasadena, CA, United States
Pattern-Recognition System for Approaching a Known Target
Huntsberger, Terrance; Cheng, Yang; NASA Tech Briefs, March 2008; March 2008; pp. 2; In English; Original contains color and black and white illustrations
Report No.(s): NPO-41867; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2667
A closed-loop pattern-recognition system is designed to provide guidance for maneuvering a small exploratory robotic vehicle (rover) on Mars to return to a landed spacecraft to deliver soil and rock samples that the spacecraft would subsequently bring back to Earth. The system could be adapted to terrestrial use in guiding mobile robots to approach known structures that humans could not approach safely, for such purposes as reconnaissance in military or law-enforcement applications, terrestrial scientific exploration, and removal of explosive or other hazardous items. The system has been demonstrated in experiments in which the Field Integrated Design and Operations (FIDO) rover (a prototype Mars rover equipped with a video camera for guidance) is made to return to a mockup of Mars-lander spacecraft. The FIDO rover camera autonomously acquires an image of the lander from a distance of 125 m in an outdoor environment. Then under guidance by an algorithm that performs fusion of multiple line and texture features in digitized images acquired by the camera, the rover traverses the intervening terrain, using features derived from images of the lander truss structure. Then by use of precise pattern matching for determining the position and orientation of the rover relative to the lander, the rover aligns itself with the bottom of ramps extending from the lander, in preparation for climbing the ramps to deliver samples to the lander. The most innovative aspect of the system is a set of pattern-recognition algorithms that govern a three-phase visual-guidance sequence for approaching the lander. During the first phase, a multifeature fusion algorithm integrates the outputs of a horizontal-line-detection algorithm and a wavelet-transform-based visual-area-of-interest algorithm for detecting the lander from a significant distance. The horizontal-line-detection algorithm is used to determine candidate lander locations based on detection of a horizontal deck that is part of the lander.
Author
PATTERN RECOGNITION; TARGET RECOGNITION; ALGORITHMS; WAVELET ANALYSIS; MULTISENSOR FUSION; MARS SURFACE; ROVING VEHICLES; MANEUVERS
20090020473 California Inst. of Tech., Pasadena, CA, United States
Scheme for Quantum Computing Immune to Decoherence
Williams, Colin; Vatan, Farrokh; NASA Tech Briefs, March 2008; March 2008; pp. 3; In English
Report No.(s): NPO-42996; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2669
A constructive scheme has been devised to enable mapping of any quantum computation into a spintronic circuit in which the computation is encoded in a basis that is, in principle, immune to quantum decoherence. The scheme is implemented by an algorithm that utilizes multiple physical spins to encode each logical bit in such a way that collective errors affecting all the physical spins do not disturb the logical bit. The scheme is expected to be of use to experimenters working on spintronic implementations of quantum logic. Spintronic computing devices use quantum-mechanical spins (typically, electron spins) to encode logical bits. Bits thus encoded (denoted qubits) are potentially susceptible to errors caused by noise and decoherence. The traditional model of quantum computation is based partly on the assumption that each qubit is implemented by use of a single two-state quantum system, such as an electron or other spin-1.2 particle. It can be surprisingly difficult to achieve certain gate operations . most notably, those of arbitrary 1-qubit gates . in spintronic hardware according to this model. However, ironically, certain 2-qubit interactions (in particular, spin-spin exchange interactions) can be achieved relatively easily in spintronic hardware. Therefore, it would be fortunate if it were possible to implement any 1-qubit gate by use of a spin-spin exchange interaction. While such a direct representation is not possible, it is possible to achieve an arbitrary 1-qubit gate indirectly by means of a sequence of four spin-spin exchange interactions, which could be implemented by use of four exchange gates. Accordingly, the present scheme provides for mapping any 1-qubit gate in the logical basis into an equivalent sequence of at most four spin-spin exchange interactions in the physical (encoded) basis. The complexity of the mathematical derivation of the scheme from basic quantum principles precludes a description within this article; it must suffice to report that the derivation provides explicit constructions for finding the exchange couplings in the physical basis needed to implement any arbitrary 1-qubit gate. These constructions lead to spintronic encodings of quantum logic that are more efficient than those of a previously published scheme that utilizes a universal but fixed set of gates.
Author
CODING; QUANTUM COMPUTATION; COUPLINGS; CIRCUITS; COMPUTATION
20090020474 California Inst. of Tech., Pasadena, CA, United States
Microfluidics, Chromatography, and Atomic-Force Microscopy
Anderson, Mark; NASA Tech Briefs, March 2008; March 2008; pp. 25-2; In English; Original contains color illustrations
Report No.(s): NPO-41431; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2666
A Raman-and-atomic-force microscope (RAFM) has been shown to be capable of performing several liquid-transfer and sensory functions essential for the operation of a microfluidic laboratory on a chip that would be used to perform rapid, sensitive chromatographic and spectro-chemical analyses of unprecedentedly small quantities of liquids. The most novel aspect of this development lies in the exploitation of capillary and shear effects at the atomic-force-microscope (AFM) tip to produce shear-driven flow of liquids along open microchannels of a microfluidic device. The RAFM can also be used to perform such functions as imaging liquids in microchannels; removing liquid samples from channels for very sensitive, tip-localized spectrochemical analyses; measuring a quantity of liquid adhering to the tip; and dip-pen deposition from a chromatographic device. A commercial Raman-spectroscopy system and a commercial AFM were integrated to make the RAFM so as to be able to perform simultaneous topographical AFM imaging and surface-enhanced Raman spectroscopy (SERS) at the AFM tip. The Raman-spectroscopy system includes a Raman microprobe attached to an optical microscope, the translation stage of which is modified to accommodate the AFM head. The Raman laser excitation beam, which is aimed at the AFM tip, has a wavelength of 785 nm and a diameter of about 5 m, and its power is adjustable up to 10 mW. The AFM is coated with gold to enable tip-localized SERS.
Author
ATOMIC FORCE MICROSCOPY; CHROMATOGRAPHY; MICROFLUIDIC DEVICES; LIQUIDS; TRANSFER FUNCTIONS; SPECTROSCOPIC ANALYSIS; RAMAN SPECTROSCOPY; CHEMICAL ANALYSIS; MICROANALYSIS; SHEAR FLOW
20090020475 NASA Johnson Space Center, Houston, TX, United States
Compact Directional Microwave Antenna for Localized Heating
Fink, Patrick W.; Lin, Gregory Y.; Chu, Andrew W.; Dobbins, Justin A.; Arndt, G. Dickey; Ngo, Phong; NASA Tech Briefs, March 2008; March 2008; pp. 18-1; In English; Original contains color illustrations
Report No.(s): MSC-23781; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.defensetechbriefs.com/component/content/article/2661-msc-23781
A directional, catheter-sized cylindrical antenna has been developed for localized delivery of microwave radiation for heating (and thus killing) diseased tissue without excessively heating nearby healthy tissue. By "localized" is meant that the antenna radiates much more in a selected azimuthal direction than in the opposite radial direction, so that it heats tissue much more on one side than it does on the opposite side. This antenna can be inserted using either a catheter or a syringe. A 2.4-mm prototype was tested, although smaller antennas are possible. Prior compact, cylindrical antennas designed for therapeutic localized hyperthermia do not exhibit such directionality; that is, they radiate in approximately axisymmetric patterns. Prior directional antennas designed for the same purpose have been, variously, (1) too large to fit within catheters or (2) too large, after deployment from catheters, to fit within the confines of most human organs. In contrast, the present antenna offers a high degree of directionality and is compact enough to be useable as a catheter in some applications.
Author
MICROWAVE ANTENNAS; RADIANT HEATING; CYLINDRICAL ANTENNAS; DIRECTIONAL ANTENNAS; MEDICAL EQUIPMENT; CATHETERIZATION
20090020476 Mississippi State Univ., Mississippi State, MS, United States
Using Hyperspectral Imagery to Identify Turfgrass Stresses
Hutto, Kendall; Shaw, David; NASA Tech Briefs, March 2008; March 2008; pp. 1; In English
Report No.(s): SSC-00270-1; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2660
The use of a form of remote sensing to aid in the management of large turfgrass fields (e.g. golf courses) has been proposed. A turfgrass field of interest would be surveyed in sunlight by use of an airborne hyperspectral imaging system, then the raw observational data would be preprocessed into hyperspectral reflectance image data. These data would be further processed to identify turfgrass stresses, to determine the spatial distributions of those stresses, and to generate maps showing the spatial distributions. Until now, chemicals and water have often been applied, variously, (1) indiscriminately to an entire turfgrass field without regard to localization of specific stresses or (2) to visible and possibly localized signs of stress for example, browning, damage from traffic, or conspicuous growth of weeds. Indiscriminate application is uneconomical and environmentally unsound; the amounts of water and chemicals consumed could be insufficient in some areas and excessive in most areas, and excess chemicals can leak into the environment. In cases in which developing stresses do not show visible signs at first, it could be more economical and effective to take corrective action before visible signs appear. By enabling early identification of specific stresses and their locations, the proposed method would provide guidance for planning more effective, more economical, and more environmentally sound turfgrass-management practices, including application of chemicals and water, aeration, and mowing. The underlying concept of using hyperspectral imagery to generate stress maps as guides to efficient management of vegetation in large fields is not new; it has been applied in the growth of crops to be harvested. What is new here is the effort to develop an algorithm that processes hyperspectral reflectance data into spectral indices specific to stresses in turfgrass. The development effort has included a study in which small turfgrass plots that were, variously, healthy or subjected to a variety of controlled stresses were observed by use of a hand-held spectroradiometer. The spectroradiometer readings in the wavelength range from 350 to 1,000 nm were processed to extract hyperspectral reflectance data, which, in turn, were analyzed to find correlations with the controlled stresses. Several indices were found to be correlated with drought stress and to be potentially useful for identifying drought stress before visible symptoms appear.
Author
IMAGING TECHNIQUES; REMOTE SENSING; REFLECTANCE; SPATIAL DISTRIBUTION; TERRAIN; GRASSES
20090020477 NASA Langley Research Center, Hampton, VA, United States
WRATS Integrated Data Acquisition System
Piatak, David J.; NASA Tech Briefs, March 2008; March 2008; pp. 5-; In English; Original contains color illustrations
Report No.(s): LAR-17486; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/content/view/2647/34/
The Wing and Rotor Aeroelastic Test System (WRATS) data acquisition system (DAS) is a 64-channel data acquisition display and analysis system specifically designed for use with the WRATS 1/5-scale V-22 tiltrotor model of the Bell Osprey. It is the primary data acquisition system for experimental aeroelastic testing of the WRATS model for the purpose of characterizing the aeromechanical and aeroelastic stability of prototype tiltrotor configurations. The WRATS DAS was also used during aeroelastic testing of Bell Helicopter Textron s Quad-Tiltrotor (QTR) design concept, a test which received international attention. The LabVIEW-based design is portable and capable of powering and conditioning over 64 channels of dynamic data at sampling rates up to 1,000 Hz. The system includes a 60-second circular data archive, an integrated model swashplate excitation system, a moving block damping application for calculation of whirl flutter mode subcritical damping, a loads and safety monitor, a pilot-control console display, data analysis capabilities, and instrumentation calibration functions. Three networked computers running custom-designed LabVIEW software acquire data through National Instruments data acquisition hardware. The aeroelastic model (see figure) was tested with the DAS at two facilities at NASA Langley, the Transonic Dynamics Tunnel (TDT) and the Rotorcraft Hover Test Facility (RHTF). Because of the need for seamless transition between testing at these facilities, DAS is portable. The software is capable of harmonic analysis of periodic time history data, Fast Fourier Transform calculations, power spectral density calculations, and on-line calibration of test instrumentation. DAS has a circular buffer archive to ensure critical data is not lost in event of model failure/incident, as well as a sample-and-hold capability for phase-correct time history data.
Author
DATA ACQUISITION; ROTARY WING AIRCRAFT; AEROELASTICITY; V-22 AIRCRAFT; TILT ROTOR AIRCRAFT; ROTOR AERODYNAMICS; HARMONIC ANALYSIS; DYNAMIC TESTS
20090020478 California Inst. of Tech., Pasadena, CA, United States
Orchestrator Telemetry Processing Pipeline
Powell, Mark; Mittman, David; Joswig, Joseph; Crockett, Thomas; Norris, Jeffrey; NASA Tech Briefs, March 2008; March 2008; pp. 3; In English
Report No.(s): NPO-44561; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2668
Orchestrator is a software application infrastructure for telemetry monitoring, logging, processing, and distribution. The architecture has been applied to support operations of a variety of planetary rovers. Built in Java with the Eclipse Rich Client Platform, Orchestrator can run on most commonly used operating systems. The pipeline supports configurable parallel processing that can significantly reduce the time needed to process a large volume of data products. Processors in the pipeline implement a simple Java interface and declare their required input from upstream processors. Orchestrator is programmatically constructed by specifying a list of Java processor classes that are initiated at runtime to form the pipeline. Input dependencies are checked at runtime. Fault tolerance can be configured to attempt continuation of processing in the event of an error or failed input dependency if possible, or to abort further processing when an error is detected. This innovation also provides support for Java Message Service broadcasts of telemetry objects to clients and provides a file system and relational database logging of telemetry. Orchestrator supports remote monitoring and control of the pipeline using browser-based JMX controls and provides several integration paths for pre-compiled legacy data processors. At the time of this reporting, the Orchestrator architecture has been used by four NASA customers to build telemetry pipelines to support field operations. Example applications include high-volume stereo image capture and processing, simultaneous data monitoring and logging from multiple vehicles. Example telemetry processors used in field test operations support include vehicle position, attitude, articulation, GPS location, power, and stereo images.
Author
ARCHITECTURE (COMPUTERS); TELEMETRY; DATA PROCESSING EQUIPMENT; SUPPORT SYSTEMS; PARALLEL PROCESSING (COMPUTERS); JAVA (PROGRAMMING LANGUAGE); GLOBAL POSITIONING SYSTEM; IMAGE PROCESSING
20090020479 California Inst. of Tech., Pasadena, CA, United States
Tailored Asymmetry for Enhanced Coupling to WGM Resonators
Mohageg, Makan; Maleki, Lute; NASA Tech Briefs, March 2008; March 2008; pp. 1; In English; Original contains color illustrations
Report No.(s): NPO-43832; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.defensetechbriefs.com/component/content/article/2653
Coupling of light into and out of whispering- gallery-mode (WGM) optical resonators can be enhanced by designing and fabricating the resonators to have certain non-axisymmetric shapes (see figure). Such WGM resonators also exhibit the same ultrahigh values of the resonance quality factor (Q) as do prior WGM resonators. These WGM resonators are potentially useful as tunable narrow-band optical filters having throughput levels near unity, high-speed optical switches, and low-threshold laser resonators. These WGM resonators could also be used in experiments to investigate coupling between high-Q and chaotic modes within the resonators. For a WGM resonator made of an optically nonlinear material (e.g., lithium niobate) or another material having a high index of refraction, a prism made of a material having a higher index of refraction (e.g., diamond) must be used as part of the coupling optics. For coupling of a beam of light into (or out of) the high-Q resonator modes, the beam must be made to approach (or recede from) the resonator at a critical angle determined by the indices of refraction of the resonator and prism materials. In the case of a lithium niobate/diamond interface, this angle is approximately 22 .
Author
ASYMMETRY; WHISPERING GALLERY MODES; TUNABLE FILTERS; Q FACTORS; OPTICAL RESONATORS; SHAPES; REFRACTIVITY; LASER OUTPUTS; OPTICAL FILTERS
20090020480 California Inst. of Tech., Pasadena, CA, United States
Nano-Multiplication-Region Avalanche Photodiodes and Arrays
Zheng, Xinyu; Pain, Bedabrata; Cunningham, Thomas; NASA Tech Briefs, March 2008; March 2008; pp. 9-1; In English; Original contains color illustrations
Report No.(s): NPO-42276; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2651
Nano-multiplication-region avalanche photodiodes (NAPDs), and imaging arrays of NAPDs integrated with complementary metal oxide/semiconductor (CMOS) active-pixel-sensor integrated circuitry, are being developed for applications in which there are requirements for high-sensitivity (including photoncounting) detection and imaging at wavelengths from about 250 to 950 nm. With respect to sensitivity and to such other characteristics as speed, geometric array format, radiation hardness, power demand of associated circuitry, size, weight, and robustness, NAPDs and arrays thereof are expected to be superior to prior photodetectors and arrays including CMOS active-pixel sensors (APSs), charge-coupled devices (CCDs), traditional APDs, and microchannelplate/ CCD combinations. Figure 1 depicts a conceptual NAPD array, integrated with APS circuitry, fabricated on a thick silicon-on-insulator wafer (SOI). Figure 2 presents selected aspects of the structure of a typical single pixel, which would include a metal oxide/semiconductor field-effect transistor (MOSFET) integrated with the NAPD. The NAPDs would reside in silicon islands formed on the buried oxide (BOX) layer of the SOI wafer. The silicon islands would be surrounded by oxide-filled insulation trenches, which, together with the BOX layer, would constitute an oxide embedding structure. There would be two kinds of silicon islands: NAPD islands for the NAPDs and MOSFET islands for in-pixel and global CMOS circuits. Typically, the silicon islands would be made between 5 and 10 m thick, but, if necessary, the thickness could be chosen outside this range. The side walls of the silicon islands would be heavily doped with electron-acceptor impurities (p+-doped) to form anodes for the photodiodes and guard layers for the MOSFETs. A nanoscale reach-through structure at the front (top in the figures) central position of each NAPD island would contain the APD multiplication region. Typically, the reach-through structure would be about 0.1 microns in diameter and between 0.3 and 0.4 nm high. The top layer in the reach-through structure would be heavily doped with electron-donor impurities (n+-doped) to make it act as a cathode. A layer beneath the cathode, between 0.1 and 0.2 nm thick, would be p-doped to a concentration .10(exp 17)cu cm. A thin n+-doped polysilicon pad would be formed on the top of the cathode to protect the cathode against erosion during a metal-silicon alloying step that would be part of the process of fabricating the array.
Author
PHOTODIODES; SILICON OXIDES; SILICON POLYMERS; PHOTOMETERS; CHARGE COUPLED DEVICES; DOPED CRYSTALS; FIELD EFFECT TRANSISTORS; METAL OXIDE SEMICONDUCTORS; AVALANCHE DIODES
20090020481 California Inst. of Tech., Pasadena, CA, United States
Phase Calibration of Antenna Arrays Aimed at Spacecraft
Vilnrotter, Victor; Lee, Dennis; Paal, Leslie; Mukai, Ryan; Cornish, Timothy; NASA Tech Briefs, March 2008; March 2008; pp. 3; In English
Report No.(s): NPO-43647; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2671
A document describes a method of calibrating phase differences among ground antennas in an array so that the maximum-intensity direction of the far-field interference pattern of the array coincides with the direction for aiming the antennas to enable radio communication with a distant spacecraft. The method pertains to an array typically comprising between two and four 34-m (or similar size) antennas. The antennas are first calibrated pair-wise to maximize the uplink power received at a different spacecraft that is close enough for communication via a single ground antenna. In the calibration procedure, the phase of the signal transmitted by one of the antennas is ramped through a complete cycle, thereby causing the interference pattern to sweep over this closer spacecraft and guaranteeing that, at some point during the sweep, this spacecraft is illuminated at maximum intensity. The varying received uplink power is measured by a receiver in the closer spacecraft and the measurement data are transmitted to a ground station to enable determination of the optimum phase adjustment for the direction to the closer spacecraft. This adjustment is then translated to the look direction of the distant spacecraft, which could not be reached effectively using only one antenna.
Author
ANTENNA ARRAYS; CALIBRATING; RADIO COMMUNICATION; GROUND STATIONS; FAR FIELDS
20090020482 California Inst. of Tech., Pasadena, CA, United States
Ring Bus Architecture for a Solid-State Recorder
Walker, W. John; Kopf, Edward; Cox, Brian; NASA Tech Briefs, March 2008; March 2008; pp. 3; In English
Report No.(s): NPO-45132; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2672
A document concisely describes a ring bus architecture for a proposed solid-state recorder (SSR) that would serve as buffer of data to be transmitted from a spacecraft to Earth. This architecture would afford fault tolerance needed for reliable operation in an anticipated high-radiation environment in which traditional SSRs cannot operate reliably. Features of the architecture include one or more controller boards and multiple memory boards interconnected in a ringlike topology. The interconnections would be high-speed serial links complying with the Institute of Electrical and Electronics Engineers (IEEE) standard 1393 (which pertains to a spaceborne fiber-optic data bus). Accordingly, each controller and memory board would be equipped with an IEEE-1393-compliant ring-bus-interface unit. The ringlike topology and the multiplicity of memory boards (and, optionally, of controller boards) would afford the redundancy needed for fault tolerance. Each board would be a fault-containment region. The IEEE 1393 links could be routed so that the SSR would continue to function even in the event of multiple failures. This architecture would also support scalability over a wide range. In a fully redundant configuration, it could accommodate between 1 and 125 memory boards.
Author
SOLID STATE; CHANNELS (DATA TRANSMISSION); FAULT TOLERANCE; FIBER OPTICS; HIGH SPEED; CONTROLLERS
20090020483 California Inst. of Tech., Pasadena, CA, United States
Image Compression Algorithm Altered to Improve Stereo Ranging
Kiely, Aaron; NASA Tech Briefs, March 2008; March 2008; pp. 3; In English
Report No.(s): NPO-44647; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2673
A report discusses a modification of the ICER image-data-compression algorithm to increase the accuracy of ranging computations performed on compressed stereoscopic image pairs captured by cameras aboard the Mars Exploration Rovers. (ICER and variants thereof were discussed in several prior NASA Tech Briefs articles.) Like many image compressors, ICER was designed to minimize a mean-square-error measure of distortion in reconstructed images as a function of the compressed data volume. The present modification of ICER was preceded by formulation of an alternative error measure, an image-quality metric that focuses on stereoscopic-ranging quality and takes account of image-processing steps in the stereoscopic-ranging process. This metric was used in empirical evaluation of bit planes of wavelet-transform subbands that are generated in ICER. The present modification, which is a change in a bit-plane prioritization rule in ICER, was adopted on the basis of this evaluation. This modification changes the order in which image data are encoded, such that when ICER is used for lossy compression, better stereoscopic-ranging results are obtained as a function of the compressed data volume.
Author
DATA COMPRESSION; IMAGE PROCESSING; ALGORITHMS; WAVELET ANALYSIS; NASA PROGRAMS; RANGEFINDING; IMAGE RESOLUTION
20090020484 California Inst. of Tech., Pasadena, CA, United States
Disabling CNT Electronic Devices by Use of Electron Beams
Petkov, Mihail; NASA Tech Briefs, March 2008; March 2008; pp. 1; In English; Original contains color illustrations
Report No.(s): NPO-41343; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2652
Bombardment with tightly focused electron beams has been suggested as a means of electrically disabling selected individual carbon-nanotubes (CNTs) in electronic devices. Evidence in support of the suggestion was obtained in an experiment in which a CNT field-effect transistor was disabled (see figure) by focusing a 1-keV electron beam on a CNT that served as the active channel of a field-effect transistor (FET). Such bombardment could be useful in the manufacture of nonvolatile-memory circuits containing CNT FETs. Ultimately, in order to obtain the best electronic performances in CNT FETs and other electronic devices, it will be necessary to fabricate the devices such that each one contains only a single CNT as an active element. At present, this is difficult because there is no way to grow a single CNT at a specific location and with a specific orientation. Instead, the common practice is to build CNTs into electronic devices by relying on spatial distribution to bridge contacts. This practice results in some devices containing no CNTs and some devices containing more than one CNT. Thus, CNT FETs have statistically distributed electronic characteristics (including switching voltages, gains, and mixtures of metallic and semiconducting CNTs). According to the suggestion, by using a 1-keV electron beam (e.g., a beam from a scanning electron microscope), a particular nanotube could be rendered electrically dysfunctional. This procedure could be repeated as many times as necessary on different CNTs in a device until all of the excess CNTs in the device had been disabled, leaving only one CNT as an active element (e.g., as FET channel). The physical mechanism through which a CNT becomes electrically disabled is not yet understood. On one hand, data in the literature show that electron kinetic energy >86 keV is needed to cause displacement damage in a CNT. On the other hand, inasmuch as a 1-keV beam focused on a small spot (typically a few tens of nanometers wide) deposits a significant amount of energy in a small volume, the energy density may suffice to thermally induce structural and/or electronic changes that disable the CNT. Research may be warranted to investigate this effect in detail.
Author
CARBON NANOTUBES; ELECTRIC POTENTIAL; SCANNING ELECTRON MICROSCOPY; KINETIC ENERGY; FIELD EFFECT TRANSISTORS; ELECTRON ENERGY; SPATIAL DISTRIBUTION
20090020485 Toledo Univ., OH, United States
Conical Bearingless Motor/Generators
Kascak, P.; Jansen, R.; Dever, T.; NASA Tech Briefs, March 2008; March 2008; pp. 1; In English; Original contains color illustrations
Report No.(s): LEW-17638-1/39-1/40-1; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2658
Motor/generators based on conical magnetic bearings have been invented as an improved alternative to prior such machines based, variously, on radial and/or axial magnetic bearings. Both the present and prior machines are members of the class of so-called bearingless or self bearing (in the sense of not containing mechanical bearings) rotary machines. Each motor/generator provides both a torque and force allowing it to either function as a motor and magnetic bearing or a generator and magnetic bearing concurrently. Because they are not subject to mechanical bearing wear, these machines have potentially long operational lives and can function without lubrication and over wide ranges of speed and temperature that include conditions under which lubricants would become depleted, degraded, or ineffective and mechanical bearings would fail. The figure shows three typical configurations of conical bearingless motor/generators. The main elements of each motor/generator are concentric rotor and stator portions having conically tapered surfaces facing each other across a gap. Because a conical motor/generator imposes both radial and axial magnetic forces, it acts, in effect, as a combination of an axial and a radial magnetic bearing. Therefore, only two conical motor/generators - one at each end of a rotor - are needed to effect complete magnetic leviation of the rotor, whereas previously, it was necessary to use a combination of an axial and a radial magnetic bearing at each end of the rotor to achieve complete magnetic levitation and a separate motor to provide torque.
Author
MAGNETIC BEARINGS; TORQUE; LUBRICATION; MAGNETIC SUSPENSION; WEAR; STATORS; ROTORS
20090020486 California Inst. of Tech., Pasadena, CA, United States
Split-Block Waveguide Polarization Twist for 220 to 325 GHz
Ward, John; Chattopadhyay, Goutam; NASA Tech Briefs, March 2008; March 2008; pp. ; In English; Original contains color illustrations
Report No.(s): NPO-42985; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2650
A split-block waveguide circuit that rotates polarization by 90 has been designed with WR-3 input and output waveguides, which are rectangular waveguides used for a nominal frequency range of 220 to 325 GHz. Heretofore, twisted rectangular waveguides equipped with flanges at the input and output have been the standard means of rotating the polarizations of guided microwave signals. However, the fabrication and assembly of such components become difficult at high frequency due to decreasing wavelength, such that twisted rectangular waveguides become impractical at frequencies above a few hundred gigahertz. Conventional twisted rectangular waveguides are also not amenable to integration into highly miniaturized subassemblies of advanced millimeter- and submillimeter-wave detector arrays now undergoing development. In contrast, the present polarization- rotating waveguide can readily be incorporated into complex integrated waveguide circuits such as miniaturized detector arrays fabricated by either conventional end milling of metal blocks or by deep reactive ion etching of silicon blocks. Moreover, the present split-block design can be scaled up in frequency to at least 5 THz. The main step in fabricating a splitblock polarization-rotating waveguide of the present design is to cut channels having special asymmetrically shaped steps into mating upper and lower blocks (see Figure 1). The dimensions of the steps are chosen to be consistent with the WR-3 waveguide cross section, which is 0.864 by 0.432 mm. The channels are characterized by varying widths with constant depths of 0.432, 0.324, and 0.216 mm and by relatively large corner radii to facilitate fabrication. The steps effect both a geometric transition and the corresponding impedance-matched electromagnetic-polarization transition between (1) a WR-3 rectangular waveguide oriented with the electric field vector normal to the block mating surfaces and (2) a corresponding WR-3 waveguide oriented with its electric field vector parallel to the mating surfaces of the blocks. A prototype has been built and tested. Figure 2 presents test results indicative of good performance over nearly the entire WR-3 waveguide frequency band.
Author
WAVEGUIDES; SUBMILLIMETER WAVES; INTEGRATED CIRCUITS; POLARIZATION; RECTANGULAR WAVEGUIDES; HIGH FREQUENCIES; FREQUENCY RANGES; ELECTRIC FIELDS
20090020487 California Inst. of Tech., Pasadena, CA, United States
Low-Light-Shift Cesium Fountain without Mechanical Shutters
Enzer, Daphna; NASA Tech Briefs, March 2008; March 2008; pp. 2; In English; Original contains color illustrations
Report No.(s): NPO-42136; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2663
A new technique for reducing errors in a laser-cooled cesium fountain frequency standard provides for strong suppression of the light shift without need for mechanical shutters. Because mechanical shutters are typically susceptible to failure after operating times of the order of months, the elimination of mechanical shutters could contribute significantly to the reliability of frequency standards that are required to function continuously for longer time intervals. With respect to the operation of an atomic-fountain frequency standard, the term "light shift" denotes an undesired relative shift in the two energy levels of the atoms (in this case, cesium atoms) in the atomic fountain during interrogation by microwaves. The shift in energy levels translates to a frequency shift that reduces the precision and possibly accuracy of the frequency standard. For reasons too complex to describe within the space available for this article, the light shift is caused by any laser light that reaches the atoms during the microwave- interrogation period, but is strongest for near-resonance light. In the absence of any mitigating design feature, the light shift, expressed as a fraction of the standard fs frequency, could be as large as approx. 2 x 10(exp -11), the largest error in the standard. In a typical prior design, to suppress light shift, the intensity of laser light is reduced during the interrogation period by using a single-pass acoustooptic modulator to deflect the majority of light away from the main optical path. Mechanical shutters are used to block the remaining undeflected light to ensure complete attenuation. Without shutters, this remaining undeflected light could cause a light shift of as much as .10.15, which is unacceptably large in some applications. The new technique implemented here involves additionally shifting the laser wavelength off resonance by a relatively large amount (typically of the order of nanometers) during microwave interrogation. In this design, when microwave interrogation is not underway, the atoms are illuminated by a slave laser locked to the lasing frequency of a lower power master laser.
Author
FREQUENCY SHIFT; LUMINOUS INTENSITY; ENERGY LEVELS; CESIUM; ACOUSTO-OPTICS; ILLUMINATING; LIGHT BEAMS; OPTICAL RESONANCE; ERRORS
20090020488 California Inst. of Tech., Pasadena, CA, United States
Magnetic Compensation for Second-Order Doppler Shift in LITS
Burt, Eric; Tjoelker, Robert; NASA Tech Briefs, March 2008; March 2008; pp. 23-2; In English; Original contains color illustrations
Report No.(s): NPO-43199; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2838
The uncertainty in the frequency of a linear-ion-trap frequency standard (LITS) can be reduced substantially by use of a very small magnetic inhomogeneity tailored to compensate for the residual second-order Doppler shift. An effect associated with the relativistic time dilatation, one cause of the second-order Doppler shift, is ion motion that is attributable to the trapping radio-frequency (RF)electromagnetic field used to trap ions. The second-order Doppler shift is reduced by using a multi-pole trap; however it is still the largest source of systematic frequency shift in the latest generation of LITSs, which are among the most stable clocks in the world. The present compensation scheme reduces the frequency instability of the affected LITS to about a tenth of its previous value. The basic principles of prior generation LITSs were discussed in several prior NASA Tech Briefs articles. Below are recapitulated only those items of basic information necessary to place the present development in context. A LITS includes a microwave local oscillator, the frequency of which is stabilized by comparison with the frequency of the ground state hyperfine transition of 199Hg+ ions. The comparison involves a combination of optical and microwave excitation and interrogation of the ions in a linear ion trap in the presence of a nominally uniform magnetic field. In the current version of the LITS, there are two connected traps (see figure): (1) a quadrupole trap wherein the optical excitation and measurement take place and (2) a 12-pole trap (denoted the resonance trap), wherein the microwave interrogation takes place. The ions are initially loaded into the quadrupole trap and are thereafter shuttled between the two traps. Shuttling ions into the resonance trap allows sensitive microwave interrogation to take place well away from loading interference. The axial magnetic field for the resonance trap is generated by an electric current in a finely wound wire coil surrounded by magnetic shields. In the quadrupole and 12-pole traps, the potentials are produced by RF voltages applied to even numbers (4 and 12, respectively) of parallel rods equally spaced around a circle. The polarity of the voltage on each rod is opposite that of the voltage on the adjacent rod. As a result, the amplitude of the RF trapping field is zero along the centerline and increases, with radius, to a maximum value near the rods.
Author
DOPPLER EFFECT; MAGNETIC FIELD CONFIGURATIONS; MICROWAVE OSCILLATORS; RADIO FREQUENCIES; FREQUENCY SHIFT; MAGNETIC SHIELDING; NONUNIFORM MAGNETIC FIELDS; NASA PROGRAMS
20090020489 Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA, United States
Shaping Diffraction-Grating Grooves to Optimize Efficiency
Backlund, John; Wilson, Daniel; Mouroulis, Pantazis; Maker, Paul; Muller, Richard; NASA Tech Briefs, March 2008; March 2008; pp. 2; In English; Original contains color illustrations
Report No.(s): NPO-40429; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2662
A method of shaping diffraction-grating grooves to optimize the spectral efficiency, spectral range, and image quality of a spectral imaging instrument is under development. The method is based on the use of an advanced design algorithm to determine the possibly complex shape of grooves needed to obtain a desired efficiency-versus-wavelength response (see figure). Then electron- beam fabrication techniques are used to realize the required groove shape. The method could be used, for example, to make the spectral efficiency of the grating in a given wavelength range proportional to the inverse of the spectral efficiency of a photodetector array so that the overall spectral efficiency of the combination of the grating and the photodetector array would be flat. The method has thus far been applied to one-dimensional gratings only, but in principle, it is also applicable to two-dimensional gratings. The algorithm involves calculations in the spatial-frequency domain. The spatial-frequency spectrum of a grating is represented as a diffraction-order spectral-peak-width function multiplied by an efficiency function for a single grating groove. This representation affords computational efficiency and accuracy by making it possible to consider only the response from one grating groove (one period of the grating), instead of from the whole grating area, in determining the response from the entire grating. This combination of efficiency and accuracy is crucial for future extensions of the algorithm to two-dimensional designs and to designs in which polarization must also be taken into account. The algorithm begins with the definition of target values of relative efficiency that represent the desired spectral response of the grating in certain spectral frequencies calculated from the diffraction order and wavelength. The grating period is divided into a number of cells - typically, 100. The phase contribution from each cell is determined from the phase of the incident electromagnetic wave and the height of the grating surface in the cell. The total contribution from all cells to each target value is then calculated. Then a method known to specialists as the optimum-rotation-angle method is used to adjust the height of each cell so that the total response from all cells is optimized. The computation is iterative and continues until the desired response is obtained. In the event that the desired response is unphysical, the algorithm nevertheless strives to generate a grating-grove profile for which the response approximates the desired one as closely as possible.
Author
GRATINGS (SPECTRA); SHAPES; SPECTRAL SENSITIVITY; IMAGE RESOLUTION; GROOVES; DIFFRACTION
20090020490 California Inst. of Tech., Pasadena, CA, United States
Nanostructures Exploit Hybrid-Polariton Resonances
Anderson, Mark; NASA Tech Briefs, March 2008; March 2008; pp. 2; In English; Original contains color illustrations
Report No.(s): NPO-42341; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2665
Nanostructured devices that exploit the hybrid-polariton resonances arising from coupling among photons, phonons, and plasmons are subjects of research directed toward the development of infrared-spectroscopic sensors for measuring extremely small quantities of molecules of interest. The spectroscopic techniques in question are surface enhanced Raman scattering (SERS) and surface enhanced infrared absorption (SEIRA). An important intermediate goal of this research is to increase the sensitivity achievable by these techniques. The basic idea of the approach being followed in this research is to engineer nanostructured devices and thereby engineer their hybrid-polariton resonances to concentrate infrared radiation incident upon their surfaces in such a manner as to increase the absorption of the radiation for SEIRA and measure the frequency shifts of surface vibrational modes. The underlying hybrid-polariton-resonance concept is best described by reference to experimental devices that have been built and tested to demonstrate the concept. The nanostructure of each such device includes a matrix of silicon carbide particles of approximately 1 micron in diameter that are supported on a potassium bromide (KBr) or poly(tetrafluoroethylene) [PTFE] window. These grains are sputter-coated with gold grains of 40-nm size (see figure). From the perspective of classical electrodynamics, in this nanostructure, that includes a particulate or otherwise rough surface, the electric-field portion of an incident electromagnetic field becomes concentrated on the particles when optical resonance conditions are met. Going beyond the perspective of classical electrodynamics, it can be seen that when the resonance frequencies of surface phonons and surface plasmons overlap, the coupling of the resonances gives rise to an enhanced radiation-absorption or -scattering mechanism. The sizes, shapes, and aggregation of the particles determine the frequencies of the resonances. Hence, the task of designing a nanostructure to exhibit the desired radiation-absorption properties translates, in large part, to selecting particle sizes and shapes to obtain the desired enhanced coupling of energy from photons to plasmons and phonons. To broaden the spectral region(s) of enhanced absorption, one would select a distribution of particle sizes and shapes.
Author
NANOSTRUCTURES (DEVICES); POLARITONS; RESONANT FREQUENCIES; PHOTONS; MOLECULES; INFRARED RADIATION; ABSORPTION SPECTRA; FREQUENCY SHIFT
20090020491 Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA, United States
Breadboard Signal Processor for Arraying DSN Antennas
Jongeling, Andre; Sigman, Elliott; Chandra, Kumar; Trinh, Joseph; Soriano, Melissa; Navarro, Robert; Rogstad, Stephen; Goodhart, Charles; Proctor, Robert; Jourdan, Michael; Rayhrer, Benno; NASA Tech Briefs, March 2008; March 2008; pp. ; In English; Original contains color illustrations
Report No.(s): NPO-43646; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2648
A recently developed breadboard version of an advanced signal processor for arraying many antennas in NASA s Deep Space Network (DSN) can accept inputs in a 500-MHz-wide frequency band from six antennas. The next breadboard version is expected to accept inputs from 16 antennas, and a following developed version is expected to be designed according to an architecture that will be scalable to accept inputs from as many as 400 antennas. These and similar signal processors could also be used for combining multiple wide-band signals in non-DSN applications, including very-long-baseline interferometry and telecommunications. This signal processor performs functions of a wide-band FX correlator and a beam-forming signal combiner. [The term "FX" signifies that the digital samples of two given signals are fast Fourier transformed (F), then the fast Fourier transforms of the two signals are multiplied (X) prior to accumulation.] In this processor, the signals from the various antennas are broken up into channels in the frequency domain (see figure). In each frequency channel, the data from each antenna are correlated against the data from each other antenna; this is done for all antenna baselines (that is, for all antenna pairs). The results of the correlations are used to obtain calibration data to align the antenna signals in both phase and delay. Data from the various antenna frequency channels are also combined and calibration corrections are applied. The frequency-domain data thus combined are then synthesized back to the time domain for passing on to a telemetry receiver
Author
BREADBOARD MODELS; SIGNAL PROCESSING; VERY LONG BASE INTERFEROMETRY; TELECOMMUNICATION; BROADBAND; CALIBRATING; DEEP SPACE NETWORK; FAST FOURIER TRANSFORMATIONS
20090020492 California Inst. of Tech., Pasadena, CA, United States
Digital Receiver Phase Meter
Marcin, Martin; Abramovici, Alexander; NASA Tech Briefs, March 2008; March 2008; pp. ; In English; Original contains color illustrations
Report No.(s): NPO-43928; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2649
The software of a commercially available digital radio receiver has been modified to make the receiver function as a two-channel low-noise phase meter. This phase meter is a prototype in the continuing development of a phase meter for a system in which radiofrequency (RF) signals in the two channels would be outputs of a spaceborne heterodyne laser interferometer for detecting gravitational waves. The frequencies of the signals could include a common Doppler-shift component of as much as 15 MHz. The phase meter is required to measure the relative phases of the signals in the two channels at a sampling rate of 10 Hz at a root power spectral density <5 microcycle/(Hz)1/2 and to be capable of determining the power spectral density of the phase difference over the frequency range from 1 mHz to 1 Hz. Such a phase meter could also be used on Earth to perform similar measurements in laser metrology of moving bodies. To illustrate part of the principle of operation of the phase meter, the figure includes a simplified block diagram of a basic singlechannel digital receiver. The input RF signal is first fed to the input terminal of an analog-to-digital converter (ADC). To prevent aliasing errors in the ADC, the sampling rate must be at least twice the input signal frequency. The sampling rate of the ADC is governed by a sampling clock, which also drives a digital local oscillator (DLO), which is a direct digital frequency synthesizer. The DLO produces samples of sine and cosine signals at a programmed tuning frequency. The sine and cosine samples are mixed with (that is, multiplied by) the samples from the ADC, then low-pass filtered to obtain in-phase (I) and quadrature (Q) signal components. A digital signal processor (DSP) computes the ratio between the Q and I components, computes the phase of the RF signal (relative to that of the DLO signal) as the arctangent of this ratio, and then averages successive such phase values over a time interval specified by the user.
Author
RADIO RECEIVERS; DIGITAL SYSTEMS; SIGNAL PROCESSING; SIGNAL ANALYZERS; RADIO COMMUNICATION; FREQUENCY RANGES; FREQUENCY SYNTHESIZERS
20090020495 NASA Dryden Flight Research Center, Edwards, CA, United States
Software Configurable Multichannel Transceiver
Freudinger, Lawrence C.; Cornelius, Harold; Hickling, Ron; Brooks, Walter; May 12, 2009; In English; 2009 Test Instrumentation Workshop, 12-14 May 2009, Ridgecrest, CA, United States
Contract(s)/Grant(s): NNX07AF17A
Report No.(s): DFRC-947; No Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020495
Emerging test instrumentation and test scenarios increasingly require network communication to manage complexity. Adapting wireless communication infrastructure to accommodate challenging testing needs can benefit from reconfigurable radio technology. A fundamental requirement for a software-definable radio system is independence from carrier frequencies, one of the radio components that to date has seen only limited progress toward programmability. This paper overviews an ongoing project to validate the viability of a promising chipset that performs conversion of radio frequency (RF) signals directly into digital data for the wireless receiver and, for the transmitter, converts digital data into RF signals. The Software Configurable Multichannel Transceiver (SCMT) enables four transmitters and four receivers in a single unit the size of a commodity disk drive, programmable for any frequency band between 1 MHz and 6 GHz.
Author
TRANSMITTER RECEIVERS; RECONFIGURABLE HARDWARE; COMPUTER PROGRAMS; RADIO FREQUENCIES; DIGITAL DATA; FREQUENCY CONVERTERS; WIRELESS COMMUNICATION; MULTICHANNEL COMMUNICATION; SYSTEMS ENGINEERING
Additions to the NASA Aeronautics and Space Database as of 06/09/2009
20090020501 NASA Johnson Space Center, Houston, TX, United States
Rare Earth Element Measurements of Melilite and Fassaite in Allende Cai by Nanosims
Ito, M.; Messenger, Scott; [2009]; In English; 72nd Annual Meeting of the Meteoritical Society, 13-18 Jul. 2009, Nancy, France
Report No.(s): JSC-CN-18339; Copyright; Avail.: CASI: A01, Hardcopy
The rare earth elements (REEs) are concentrated in CAIs by approx. 20 times the chondritic average [e.g., 1]. The REEs in CAIs are important to understand processes of CAI formation including the role of volatilization, condensation, and fractional crystallization [1,2]. REE measurements are a well established application of ion microprobes [e.g., 3]. However the spatial resolution of REE measurements by ion microprobe (approx.20 m) is not adequate to resolve heterogeneous distributions of REEs among/within minerals. We have developed methods for measuring REE with the NanoSIMS 50L at smaller spatial scales. Here we present our initial measurements of REEs in melilite and fassaite in an Allende Type-A CAI with the JSC NanoSIMS 50L. We found that the key parameters for accurate REE abundance measurements differ between the NanoSIMS and conventional SIMS, in particular the oxide-to-element ratios, the relative sensitivity factors, the energy distributions, and requisite energy offset. Our REE abundance measurements of the 100 ppm REE diopside glass standards yielded good reproducibility and accuracy, 0.5-2.5 % and 5-25 %, respectively. We determined abundances and spatial distributions of REEs in core and rim within single crystals of fassaite, and adjacent melilite with 5-10 m spatial resolution. The REE abundances in fassaite core and rim are 20-100 times CI abundance but show a large negative Eu anomaly, exhibiting a well-defined Group III pattern. This is consistent with previous work [4]. On the other hand, adjacent melilite shows modified Group II pattern with no strong depletions of Eu and Yb, and no Tm positive anomaly. REE abundances (2-10 x CI) were lower than that of fassaite. These patterns suggest that fassaite crystallized first followed by a crystallization of melilite from the residual melt. In future work, we will carry out a correlated study of O and Mg isotopes and REEs of the CAI in order to better understand the nature and timescales of its formation process and subsequent metamorphic history.
Author
MINERALOGY; RARE EARTH ELEMENTS; ABUNDANCE; METAMORPHISM (GEOLOGY); CRYSTALLIZATION; SINGLE CRYSTALS; MINERALS; CHONDRITES
20090020504 NASA Johnson Space Center, Houston, TX, United States
Carbon Raman Spectroscopy of 36 Inter-Planetary Dust Particles
Busemann, H.; Nittler, L. R.; Davidson, J.; Franchi, I. A.; Messenger, S.; Nakamura-Messenger, K.; Palma, R. L.; Pepin, R. O.; [2009]; In English; 72nd Annual Meeting of the Meteoritical Society, 13-18 Jul. 20009, Nancy, France
Report No.(s): JSC-CN-18343; Copyright; Avail.: CASI: A01, Hardcopy
Carbon Raman spectroscopy is a useful tool to determine the degree of order of organic material (OM) in extra-terrestrial matter. As shown for meteoritic OM [e.g., 2], peak parameters of D and G bands are a measure of thermal alteration, causing graphitization (order), and amorphization, e.g. during protoplanetary irradiation, causing disorder. particles (IDPs) may come from comets. However, their exact provenance is unknown. IDP collection during Earth?s passage through comet Grigg-Skjellerup?s dust stream ("GSC" collectors) may increase the probability of collecting fresh IDPs from a known, cometary source. We used Raman spectroscopy to compare 21 GSC-IDPs with 15 IDPs collected at different periods, and found that the variation among GSC-IDPs is larger than among non-GSC IDPs, with the most primitive IDPs being mostly GSC-IDPs.
Author
RAMAN SPECTROSCOPY; CARBON; AMORPHOUS MATERIALS; COMETARY ATMOSPHERES; DUST COLLECTORS; INTERPLANETARY DUST; PROBABILITY THEORY
Additions to the NASA Aeronautics and Space Database as of 06/10/2009
20090020506 NASA, Washington, DC, United States
NASA Tech Briefs, February 2008
February 2008; In English; Original contains color and black and white illustrations
Copyright; Avail.: CASI: A03, Hardcopy
Topics discussed include: Optical Measurement of Mass Flow of a Two-Phase Fluid; Selectable-Tip Corrosion-Testing Electrochemical Cell; Piezoelectric Bolt Breakers and Bolt Fatigue Testers; Improved Measurement of B(sub 22) of Macromolecules in a Flow Cell; Measurements by a Vector Network Analyzer at 325 to 508 GHz; Using Light to Treat Mucositis and Help Wounds Heal; Increasing Discharge Capacities of Li-(CF)(sub n) Cells; Dot-in-Well Quantum-Dot Infrared Photodetectors; Integrated Microbatteries for Implantable Medical Devices; Oxidation Behavior of Carbon Fiber-Reinforced Composites; GIDEP Batching Tool; Generic Spacecraft Model for Real-Time Simulation; Parallel-Processing Software for Creating Mosaic Images; Software for Verifying Image-Correlation Tie Points; Flexcam Image Capture Viewing and Spot Tracking; Low-Pt-Content Anode Catalyst for Direct Methanol Fuel Cells; Graphite/Cyanate Ester Face Sheets for Adaptive Optics; Atomized BaF2-CaF7 for Better-Flowing Plasma-Spray Feedstock; Nanophase Nickel-Zirconium Alloys for Fuel Cells; Vacuum Packaging of MEMS With Multiple Internal Seal Rings; Compact Two-Dimensional Spectrometer Optics; and Fault-Tolerant Coding for State Machines.
Author
ZIRCONIUM ALLOYS; MICROELECTROMECHANICAL SYSTEMS; TWO PHASE FLOW; OPTICAL MEASUREMENT; BARIUM FLUORIDES; CARBON FIBERS; FAULT TOLERANCE; FIBER COMPOSITES; NICKEL ALLOYS; ADAPTIVE OPTICS; COMPUTERIZED SIMULATION; EPOXY MATRIX COMPOSITES
20090020507 NASA Marshall Space Flight Center, Huntsville, AL, United States
Optical Measurement of Mass Flow of a Two-Phase Fluid
Wiley, John; Pedersen, Kevin; Koman, Valentin; Gregory, Don; NASA Tech Briefs, February 2008; February 2008; pp. 5-; In English; Original contains color illustrations
Report No.(s): MFS-32031-1; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/content/view/2596/34/
An optoelectronic system utilizes wavelength-dependent scattering of light for measuring the density and mass flow of a two-phase fluid in a pipe. The apparatus was invented for original use in measuring the mass flow of a two-phase cryogenic fluid (e.g., liquid hydrogen containing bubbles of hydrogen gas), but underlying principles of operation can readily be adapted to non-cryogenic two-phase fluids. The system (see figure) includes a laser module, which contains two or more laser diodes, each operating at a different wavelength. The laser module also contains beam splitters that combine the beams at the various wavelengths so as to produce two output beams, each containing all of the wavelengths. One of the multiwavelength output beams is sent, via a multimode fiberoptic cable, to a transmitting optical coupler. The other multiwavelength output beam is sent, via another multimode fiber-optic cable, to a reference detector module, wherein fiber-optic splitters split the light into several multiwavelength beams, each going to a photodiode having a spectral response that is known and that differs from the spectral responses of the other photodiodes. The outputs of these photodiodes are digitized and fed to a processor, which executes an algorithm that utilizes the known spectral responses to convert the photodiode outputs to obtain reference laser-power levels for the various wavelengths. The transmitting optical coupler is mounted in (and sealed to) a hole in the pipe and is oriented at a slant with respect to the axis of the pipe. The transmitting optical coupler contains a collimating lens and a cylindrical lens that form the light emerging from the end of the fiber-optic cable into a fan-shaped beam in a meridional plane of the pipe. Receiving optical couplers similar to the transmitting optical couplers are mounted in the same meridional plane at various longitudinal positions on the opposite side of the pipe, approximately facing the transmitting optical coupler along the same slant. Light collected by each receiving optical coupler is sent, via a multimode fiber-optic cable, to a detector module similar to the reference detector module. The outputs of the photodiodes in each detector module are digitized and processed, similarly to those of the reference detector module, to obtain indications of the amounts of light of each wavelength scattered to the corresponding receiving position. The value for each wavelength at each position is also normalized to the reference laser-power level for that wavelength. From these normalized values, the density and the mass flow rate of the fluid are estimated.
Author
BEAM SPLITTERS; COUPLING CIRCUITS; FLOW MEASUREMENT; FIBER OPTICS; LIGHT SCATTERING; OPTICAL MEASUREMENT; OPTICAL RELAY SYSTEMS; TWO PHASE FLOW; CRYOGENIC FLUIDS
20090020508 NASA Kennedy Space Center, Cocoa Beach, FL, United States
Selectable-Tip Corrosion-Testing Electrochemical Cell
Lomness, Janice; Hintze, Paul; NASA Tech Briefs, February 2008; February 2008; pp. ; In English; Original contains color illustrations
Report No.(s): KSC-13045; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/2603?task=view
The figure depicts aspects of an electrochemical cell for pitting- corrosion tests of material specimens. The cell is designed to generate a region of corrosion having a pit diameter determined by the diameter of a selectable tip. The average depth of corrosion is controlled by controlling the total electric charge passing through the cell in a test. The cell is also designed to produce minimal artifacts associated with crevice corrosion. There are three selectable tips, having diameters of 0.1 in. (0.254 cm), 0.3 in. (0.762 cm), and 0.6 in. (1.524 cm), respectively.
Author
CORROSION TESTS; ELECTROCHEMICAL CELLS; PITTING; ELECTRIC CHARGE; CRACKS
20090020509 California Inst. of Tech., Pasadena, CA, United States
Flexcam Image Capture Viewing and Spot Tracking
Rao, Shanti; NASA Tech Briefs, February 2008; February 2008; pp. 1; In English
Report No.(s): NPO-44361; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2615
Flexcam software was designed to allow continuous monitoring of the mechanical deformation of the telescope structure at Palomar Observatory. Flexcam allows the user to watch the motion of a star with a low-cost astronomical camera, to measure the motion of the star on the image plane, and to feed this data back into the telescope s control system. This automatic interaction between the camera and a user interface facilitates integration and testing. Flexcam is a CCD image capture and analysis tool for the ST-402 camera from Santa Barbara Instruments Group (SBIG). This program will automatically take a dark exposure and then continuously display corrected images. The image size, bit depth, magnification, exposure time, resolution, and filter are always displayed on the title bar. Flexcam locates the brightest pixel and then computes the centroid position of the pixels falling in a box around that pixel. This tool continuously writes the centroid position to a network file that can be used by other instruments.
Author
CAMERAS; IMAGE ANALYSIS; TEMPORAL RESOLUTION; ASTRONOMICAL PHOTOGRAPHY; CHARGE COUPLED DEVICES; MAGNIFICATION; PIXELS
20090020510 California Inst. of Tech., Pasadena, CA, United States
Measurements by a Vector Network Analyzer at 325 to 508 GHz
Fung, King Man; Samoska, Lorene; Chattopadhyay, Goutam; Gaier, Todd; Kangaslahti, Pekka; Pukala, David; Lau, Yuenie; Oleson, Charles; Denning, Anthony; NASA Tech Briefs, February 2008; February 2008; pp. ; In English
Report No.(s): NPO-44694; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2602
Recent experiments were performed in which return loss and insertion loss of waveguide test assemblies in the frequency range from 325 to 508 GHz were measured by use of a swept-frequency two-port vector network analyzer (VNA) test set. The experiments were part of a continuing effort to develop means of characterizing passive and active electronic components and systems operating at ever increasing frequencies. The waveguide test assemblies comprised WR-2.2 end sections collinear with WR-3.3 middle sections. The test set, assembled from commercially available components, included a 50-GHz VNA scattering- parameter test set and external signal synthesizers, augmented with recently developed frequency extenders, and further augmented with attenuators and amplifiers as needed to adjust radiofrequency and intermediate-frequency power levels between the aforementioned components. The tests included line-reflect-line calibration procedures, using WR-2.2 waveguide shims as the "line" standards and waveguide flange short circuits as the "reflect" standards. Calibrated dynamic ranges somewhat greater than about 20 dB for return loss and 35 dB for insertion loss were achieved. The measurement data of the test assemblies were found to substantially agree with results of computational simulations.
Author
WAVEGUIDES; SHORT CIRCUITS; INTERMEDIATE FREQUENCIES; FREQUENCY RANGES; DYNAMIC RANGE; CALIBRATING; ATTENUATORS
20090020511 California Inst. of Tech., Pasadena, CA, United States
Integrated Microbatteries for Implantable Medical Devices
Whitacre, Jay; West, William; NASA Tech Briefs, February 2008; February 2008; pp. 1; In English; Original contains color illustrations
Report No.(s): NPO-42287; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/content/view/2607/12/
Integrated microbatteries have been proposed to satisfy an anticipated need for long-life, low-rate primary batteries, having volumes less than 1 mm3, to power electronic circuitry in implantable medical devices. In one contemplated application, such a battery would be incorporated into a tubular hearing-aid device to be installed against an eardrum. This device is based on existing tube structures that have already been approved by the FDA for use in human ears. As shown in the figure, the battery would comprise a single cell at one end of the implantable tube. A small volume of Li-based primary battery cathode material would be compacted and inserted in the tube near one end, followed by a thin porous separator, followed by a pressed powder of a Li-containing alloy. Current-collecting wires would be inserted, with suitably positioned insulators to prevent a short circuit. The battery would contain a liquid electrolyte consisting of a Li-based salt in an appropriate solvent. Hermetic seals would be created by plugging both ends with a waterproof polymer followed by deposition of parylene.
Author
ELECTRIC BATTERIES; SHORT CIRCUITS; PRIMARY BATTERIES; MEDICAL EQUIPMENT; HERMETIC SEALS; CATHODES; ELECTROLYTES
20090020512 California Inst. of Tech., Pasadena, CA, United States
Software for Verifying Image-Correlation Tie Points
Klimeck, Gerhard; Yagi, Gary; NASA Tech Briefs, February 2008; February 2008; pp. 1; In English
Report No.(s): NPO-30632; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2614
A computer program enables assessment of the quality of tie points in the image-correlation processes of the software described in the immediately preceding article. Tie points are computed in mappings between corresponding pixels in the left and right images of a stereoscopic pair. The mappings are sometimes not perfect because image data can be noisy and parallax can cause some points to appear in one image but not the other. The present computer program relies on the availability of a left- right correlation map in addition to the usual right left correlation map. The additional map must be generated, which doubles the processing time. Such increased time can now be afforded in the data-processing pipeline, since the time for map generation is now reduced from about 60 to 3 minutes by the parallelization discussed in the previous article. Parallel cluster processing time, therefore, enabled this better science result. The first mapping is typically from a point (denoted by coordinates x,y) in the left image to a point (x',y') in the right image. The second mapping is from (x',y') in the right image to some point (x",y") in the left image. If (x,y) and(x",y") are identical, then the mapping is considered perfect. The perfect-match criterion can be relaxed by introducing an error window that admits of round-off error and a small amount of noise. The mapping procedure can be repeated until all points in each image not connected to points in the other image are eliminated, so that what remains are verified correlation data.
Author
IMAGE CORRELATORS; COMPUTER PROGRAMS; DATA CORRELATION; PARALLEL PROCESSING (COMPUTERS); DATA PROCESSING; COORDINATES
20090020513 California Inst. of Tech., Pasadena, CA, United States
Piezoelectric Bolt Breakers and Bolt Fatigue Testers
Sherrit, Stewart; Badescu, Mircea; Bar-Cohen, Yoseph; Barengoltz, Jack; Heckman, Vanessa; NASA Tech Briefs, February 2008; February 2008; pp. 6-; In English; Original contains color illustrations
Report No.(s): NPO-43977; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2597
A proposed family of devices for inducing fatigue in bolts in order to break the bolts would incorporate piezoelectric actuators into resonant fixtures as in ultrasonic/ sonic drills/corers and similar devices described in numerous prior NASA Tech Briefs articles. These devices were originally intended primarily for use as safer, more-reliable, more-versatile alternatives to explosive bolts heretofore used to fasten spacecraft structures that must subsequently be separated from each other quickly on command during flight. On Earth, these devices could be used for accelerated fatigue testing of bolts. Fatigue theory suggests that a bolt subjected to both a constant-amplitude dynamic (that is, oscillatory) stress and a static tensile stress below the ultimate strength of the bolt material will fail faster than will a bolt subjected to only the dynamic stress. This suggestion would be applied in a device of the proposed type. The device would be designed so that the device and the bolt to be fatigue-tested or broken would be integral parts of an assembly (see figure). The static tension in the tightened bolt would apply not only the clamping force to hold the joined structures (if any) together but also the compression necessary for proper operation of the piezoelectric actuators as parts of a resonant structural assembly. The constant-amplitude dynamic stress would be applied to the bolt by driving the piezoelectric actuators with a sinusoidal voltage at the resonance frequency of longitudinal vibration of the assembly. The amplitude of the excitation would be made large enough so that the vibration would induce fatigue in the bolt within an acceptably short time. In the spacecraft applications or in similar terrestrial structural-separation applications, devices of the proposed type would offer several advantages over explosive bolts: Unlike explosive bolts, the proposed devices would be reusable, could be tested before final use, and would not be subject to catastrophic misfire. In fatigue-testing applications, devices of the proposed type would offer advantages of compactness and low cost, relative to conventional fatigue- testing apparatuses. In both structural- separation and fatigue-testing applications, bolts to be broken or tested could be instrumented with additional ultrasonic transducers for monitoring of pertinent physical properties and of fatigue failure processes.
Author
BOLTS; FATIGUE TESTS; PIEZOELECTRIC ACTUATORS; STRESS ANALYSIS; EXPLOSIVE DEVICES; DYNAMIC LOADS; FATIGUE (MATERIALS); NASA PROGRAMS; SPACECRAFT STRUCTURES; TENSILE STRESS
20090020514 California Inst. of Tech., Pasadena, CA, United States
Fault-Tolerant Coding for State Machines
Naegle, Stephanie Taft; Burke, Gary; Newell, Michael; NASA Tech Briefs, February 2008; February 2008; pp. 2; In English
Report No.(s): NPO-41050; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2620
Two reliable fault-tolerant coding schemes have been proposed for state machines that are used in field-programmable gate arrays and application-specific integrated circuits to implement sequential logic functions. The schemes apply to strings of bits in state registers, which are typically implemented in practice as assemblies of flip-flop circuits. If a single-event upset (SEU, a radiation-induced change in the bit in one flip-flop) occurs in a state register, the state machine that contains the register could go into an erroneous state or could hang, by which is meant that the machine could remain in undefined states indefinitely. The proposed fault-tolerant coding schemes are intended to prevent the state machine from going into an erroneous or hang state when an SEU occurs. To ensure reliability of the state machine, the coding scheme for bits in the state register must satisfy the following criteria: 1. All possible states are defined. 2. An SEU brings the state machine to a known state. 3. There is no possibility of a hang state. 4. No false state is entered. 5. An SEU exerts no effect on the state machine. Fault-tolerant coding schemes that have been commonly used include binary encoding and "one-hot" encoding. Binary encoding is the simplest state machine encoding and satisfies criteria 1 through 3 if all possible states are defined. Binary encoding is a binary count of the state machine number in sequence; the table represents an eight-state example. In one-hot encoding, N bits are used to represent N states: All except one of the bits in a string are 0, and the position of the 1 in the string represents the state. With proper circuit design, one-hot encoding can satisfy criteria 1 through 4. Unfortunately, the requirement to use N bits to represent N states makes one-hot coding inefficient.
Author
FAULT TOLERANCE; APPLICATION SPECIFIC INTEGRATED CIRCUITS; SINGLE EVENT UPSETS; FIELD-PROGRAMMABLE GATE ARRAYS; CODING
20090020515 Quantum Devices, Inc., Barneveld, WI, United States
Using Light to Treat Mucositis and Help Wounds Heal
Ignatius, Robert W.; Martin, Todd S.; Kirk, Charles; NASA Tech Briefs, February 2008; February 2008; pp. ; In English; Original contains color illustrations
Report No.(s): MFS-31651; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2604
A continuing program of research and development is focusing on the use of controlled illumination by light-emitting diodes (LEDs) to treat mucositis and to accelerate healing of wounds. The basic idea is to illuminate the affected area of a patient with light of an intensity, duration, and wavelength (or combination of wavelengths) chosen to produce a therapeutic effect while generating only a minimal amount of heat. This method of treatment was originally intended for treating the mucositis that is a common complication of chemotherapy and radiation therapy for cancer. It is now also under consideration as a means to accelerate the healing of wounds and possibly also to treat exposure to chemical and radioactive warfare agents. Radiation therapy and many chemotherapeutic drugs often damage the mucosal linings of the mouth and gastrointestinal tract, leading to mouth ulcers (oral mucositis), nausea, and diarrhea. Hyperbaric-oxygen therapy is currently the standard of care for ischemic, hypoxic, infected, and otherwise slowlyhealing problem wounds, including those of oral mucositis. Hyperbaric-oxygen therapy increases such cellular activities as collagen production and angiogenesis, leading to an increased rate of healing. Biostimulation by use of laser light has also been found to be effective in treating mucositis. For hyperbaricoxygen treatment, a patient must remain inside a hyperbaric chamber for an extended time. Laser treatment is limited by laser-wavelength capabilities and by narrowness of laser beams, and usually entails the generation of significant amounts of heat.
Author
LIGHT EMITTING DIODES; RADIATION THERAPY; CHEMOTHERAPY; CANCER; LASER BEAMS; HYPERBARIC CHAMBERS; SENSORY STIMULATION; LUMINOUS INTENSITY; LASER OUTPUTS
20090020516 NASA Glenn Research Center, Cleveland, OH, United States
Atomized BaF2-CaF7 for Better-Flowing Plasma-Spray Feedstock
DellaCorte, Christopher; Stanford, Malcolm K.; NASA Tech Briefs, February 2008; February 2008; pp. 18-1; In English; Original contains color and black and white illustrations
Report No.(s): LEW-17709-1; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2617
Atomization of a molten mixture of BaF2 and CaF2 has been found to be superior to crushing of bulk solid BaF2- CaF2 as a means of producing eutectic BaF2-CaF2 powder for use as an ingredient of the powder feedstock of a high-temperature solid lubricant material known as PS304. Developed to reduce friction and wear in turbomachines that incorporate foil air bearings, PS304 is applied to metal substrates by plasma spraying. The constituents of PS304 are: a) An alloy of 80 weight percent Ni and 20 weight percent Cr, b) Cr2O3, c) Ag, and d) The BaF2-CaF2 eutectic, specifically, 62 weight percent BaF2 and 38 weight percent CaF2. The superiority of atomization as a means of producing the eutectic BaF2-CaF2 powder lies in (1) the shapes of the BaF2-CaF2 particles produced and (2) the resulting flow properties of the PS304 feedstock powder: The particles produced through crushing are angular, whereas those produced through atomization are more rounded. PS304 feedstock powder containing the more rounded BaF2-CaF2 particles flows more freely and more predictably, as is preferable for plasma spraying.
Author
BARIUM FLUORIDES; CALCIUM FLUORIDES; CHROMIUM OXIDES; HIGH TEMPERATURE LUBRICANTS; METAL SPRAYING; TURBOMACHINERY; GAS BEARINGS; PLASMA SPRAYING
20090020517 California Inst. of Tech., Pasadena, CA, United States
Nanophase Nickel-Zirconium Alloys for Fuel Cells
Narayanan, Sekharipuram; Whitacre, jay; Valdez, Thomas; NASA Tech Briefs, February 2008; February 2008; pp. 1; In English; Original contains color illustrations
Report No.(s): NPO-40415; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/content/view/2618/34/
Nanophase nickel-zirconium alloys have been investigated for use as electrically conductive coatings and catalyst supports in fuel cells. Heretofore, noble metals have been used because they resist corrosion in the harsh, acidic fuel cell interior environments. However, the high cost of noble metals has prompted a search for less-costly substitutes. Nickel-zirconium alloys belong to a class of base metal alloys formed from transition elements of widely different d-electron configurations. These alloys generally exhibit unique physical, chemical, and metallurgical properties that can include corrosion resistance. Inasmuch as corrosion is accelerated by free-energy differences between bulk material and grain boundaries, it was conjectured that amorphous (glassy) and nanophase forms of these alloys could offer the desired corrosion resistance. For experiments to test the conjecture, thin alloy films containing various proportions of nickel and zirconium were deposited by magnetron and radiofrequency co-sputtering of nickel and zirconium. The results of x-ray diffraction studies of the deposited films suggested that the films had a nanophase and nearly amorphous character.
Author
AMORPHOUS MATERIALS; NICKEL ALLOYS; ZIRCONIUM ALLOYS; FUEL CELLS; CORROSION RESISTANCE; METAL FILMS; X RAY DIFFRACTION; NOBLE METALS; MAGNETRON SPUTTERING; ELECTRICAL RESISTIVITY
20090020518 California Inst. of Tech., Pasadena, CA, United States
GIDEP Batching Tool
Fong, Danny; Odell,Dorice; Barry, Peter; Abrahamian, Tomik; NASA Tech Briefs, February 2008; February 2008; pp. 1; In English
Report No.(s): NPO-43661; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2611
This software provides internal, automated search mechanics of GIDEP (Government- Industry Data Exchange Program) Alert data imported from the GIDEP government Web site. The batching tool allows the import of a single parts list in tab-delimited text format into the local JPL GIDEP database. Delimiters from every part number are removed. The original part numbers with delimiters are compared, as well as the newly generated list without the delimiters. The two lists run against the GIDEP imports, and output any matches. This feature only works with Netscape 2.0 or greater, or Internet Explorer 4.0 or greater. The user selects the browser button to choose a text file to import. When the submit button is pressed, this script will import alerts from the text file into the local JPL GIDEP database. This batch tool provides complete in-house control over exported material and data for automated batch match abilities. The batching tool has the ability to match capabilities of the parts list to tables, and yields results that aid further research and analysis. This provides more control over GIDEP information for metrics and reports information not provided by the government site. This software yields results quickly and gives more control over external data from the government site in order to generate other reports not available from the external source. There is enough space to store years of data. The program relates to risk identification and management with regard to projects and GIDEP alert information encompassing flight parts for space exploration.
Author
COMPUTER PROGRAMS; SPACE EXPLORATION; RISK MANAGEMENT; DATA BASES; TABS (CONTROL SURFACES)
20090020519 NASA Langley Research Center, Hampton, VA, United States
Generic Spacecraft Model for Real-Time Simulation
Kenney, Patrick S.; Ragsdale, William; Neuhaus, Jason R.; NASA Tech Briefs, February 2008; February 2008; pp. 1; In English
Report No.(s): LAR-17534; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2612
Generic Spacecraft is the name of an evolving library of software that provides for simulation of a generic spacecraft that can orbit the Earth and land on the Moon (and, eventually, on Mars). This library is incorporated into the Langley Standard Realtime Simulation in C++ (LaSRS++) software framework. The generic-spacecraft simulation serves as a test bed for modeling spacecraft dynamics, propulsion, control systems, guidance, and displays. The Generic Spacecraft library supplements the LaSRS++ framework with an interface that facilitates the connection of new models into the LaSRS++ simulation by eliminating what would otherwise be the necessity of writing additional C++ classes to record data from the models and code to display values on graphical user interfaces (GUIs): The library includes routines for integrating new models into the LaSRS++ framework, identifying model inputs and outputs with full descriptions and units identified, recording data, and automatically generating graphical user interfaces (GUIs). The library is designed to be used in a manner similar to that of LaSRS++ software components for simulating vehicles other than the generic spacecraft. The user specifies (1) a spacecraft and individual models to be constructed and (2) connections between individual model inputs and outputs.
Author
REAL TIME OPERATION; COMPUTERIZED SIMULATION; SPACECRAFT MODELS; PROPULSION SYSTEM CONFIGURATIONS; GRAPHICAL USER INTERFACE; DISPLAY DEVICES; SPACECRAFT PROPULSION; COMPUTER PROGRAMS
20090020520 Bennett Optical Research, Inc., Ridgecrest, CA, United States
Graphite/Cyanate Ester Face Sheets for Adaptive Optics
Bennett, Harold; Shaffer, Joseph; Romeo, Robert; NASA Tech Briefs, February 2008; February 2008; pp. 17-1; In English
Report No.(s): MFS-32337-1; Copyright; Avail.: CASI: A01, Hardcopy
It has been proposed that thin face sheets of wide-aperture deformable mirrors in adaptive-optics systems be made from a composite material consisting of cyanate ester filled with graphite. This composite material appears to offer an attractive alternative to low-thermal-expansion glasses that are used in some conventional optics and have been considered for adaptive-optics face sheets. Adaptive-optics face sheets are required to have maximum linear dimensions of the order of meters or even tens of meters for some astronomical applications. If the face sheets were to be made from low-thermal-expansion glasses, then they would also be required to have thicknesses of the order of a millimeter so as to obtain the optimum compromise between the stiffness needed for support and the flexibility needed to enable deformation to controlled shapes by use of actuators. It is difficult to make large glass sheets having thicknesses less than 3 mm, and 3-mm-thick glass sheets are too stiff to be deformable to the shapes typically required for correction of wavefronts of light that has traversed the terrestrial atmosphere. Moreover, the primary commercially produced candidate low-thermal-expansion glass is easily fractured when in the form of thin face sheets. Graphite-filled cyanate ester has relevant properties similar to those of the low-expansion glasses. These properties include a coefficient of thermal expansion (CTE) of the order of a hundredth of the CTEs of other typical mirror materials. The Young s modulus (which quantifies stiffness in tension and compression) of graphite-filled cyanate ester is also similar to the Young's moduli of low-thermal-expansion glasses. However, the fracture toughness of graphite-filled cyanate ester is much greater than that of the primary candidate low-thermal-expansion glass. Therefore, graphite-filled cyanate ester could be made into nearly unbreakable face sheets, having maximum linear dimensions greater than a meter and thicknesses of the order of a millimeter, that would satisfy the requirements for use in adaptive optics.
Author
ADAPTIVE OPTICS; ESTERS; MODULUS OF ELASTICITY; THERMAL EXPANSION; COMPOSITE MATERIALS; MILLIMETER WAVES; WAVE FRONTS
20090020521 California Inst. of Tech., Pasadena, CA, United States
Low-Pt-Content Anode Catalyst for Direct Methanol Fuel Cells
Narayanan, Sekharipuram; Whitacre, Jay; NASA Tech Briefs, February 2008; February 2008; pp. 1; In English; Original contains color illustrations
Report No.(s): NPO-40841; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2616
Combinatorial experiments have led to the discovery that a nanophase alloy of Pt, Ru, Ni, and Zr is effective as an anode catalyst material for direct methanol fuel cells. This discovery has practical significance in that the electronic current densities achievable by use of this alloy are comparable or larger than those obtained by use of prior Pt/Ru catalyst alloys containing greater amounts of Pt. Heretofore, the high cost of Pt has impeded the commercialization of direct methanol fuel cells. By making it possible to obtain a given level of performance at reduced Pt content (and, hence, lower cost), the discovery may lead to reduction of the economic impediment to commercialization.
Author
FUEL CELLS; COMBINATORIAL ANALYSIS; COST REDUCTION; METHYL ALCOHOL; CURRENT DENSITY; CATALYSTS
20090020522 California Inst. of Tech., Pasadena, CA, United States
Parallel-Processing Software for Creating Mosaic Images
Klimeck, Gerhard; Deen, Robert; McCauley, Michael; DeJong, Eric; NASA Tech Briefs, February 2008; February 2008; pp. 15-1; In English
Report No.(s): NPO-30630; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2613
A computer program implements parallel processing for nearly real-time creation of panoramic mosaics of images of terrain acquired by video cameras on an exploratory robotic vehicle (e.g., a Mars rover). Because the original images are typically acquired at various camera positions and orientations, it is necessary to warp the images into the reference frame of the mosaic before stitching them together to create the mosaic. [Also see "Parallel-Processing Software for Correlating Stereo Images," Software Supplement to NASA Tech Briefs, Vol. 31, No. 9 (September 2007) page 26.] The warping algorithm in this computer program reflects the considerations that (1) for every pixel in the desired final mosaic, a good corresponding point must be found in one or more of the original images and (2) for this purpose, one needs a good mathematical model of the cameras and a good correlation of individual pixels with respect to their positions in three dimensions. The desired mosaic is divided into slices, each of which is assigned to one of a number of central processing units (CPUs) operating simultaneously. The results from the CPUs are gathered and placed into the final mosaic. The time taken to create the mosaic depends upon the number of CPUs, the speed of each CPU, and whether a local or a remote data-staging mechanism is used.
Author
PARALLEL PROCESSING (COMPUTERS); MOSAICS; REAL TIME OPERATION; CENTRAL PROCESSING UNITS; COMPUTER PROGRAMS; IMAGE PROCESSING; MARS SURFACE; ROBOTICS; PIXELS; CAMERAS
20090020523 NASA Glenn Research Center, Cleveland, OH, United States
Oxidation Behavior of Carbon Fiber-Reinforced Composites
Sullivan, Roy M.; NASA Tech Briefs, February 2008; February 2008; pp. 1; In English
Report No.(s): LEW-18212-1; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2610
OXIMAP is a numerical (FEA-based) solution tool capable of calculating the carbon fiber and fiber coating oxidation patterns within any arbitrarily shaped carbon silicon carbide composite structure as a function of time, temperature, and the environmental oxygen partial pressure. The mathematical formulation is derived from the mechanics of the flow of ideal gases through a chemically reacting, porous solid. The result of the formulation is a set of two coupled, non-linear differential equations written in terms of the oxidant and oxide partial pressures. The differential equations are solved simultaneously to obtain the partial vapor pressures of the oxidant and oxides as a function of the spatial location and time. The local rate of carbon oxidation is determined at each time step using the map of the local oxidant partial vapor pressure along with the Arrhenius rate equation. The non-linear differential equations are cast into matrix equations by applying the Bubnov-Galerkin weighted residual finite element method, allowing for the solution of the differential equations numerically.
Author
CARBON FIBERS; FIBER COMPOSITES; OXIDATION; TIME DEPENDENCE; VAPOR PRESSURE; REACTION KINETICS; EPOXY MATRIX COMPOSITES; SILICON CARBIDES; TIME TEMPERATURE PARAMETER; DIFFERENTIAL EQUATIONS
20090020524 California Inst. of Tech., Pasadena, CA, United States
Vacuum Packaging of MEMS With Multiple Internal Seal Rings
Hayworth, Ken; Yee, Karl; Shcheglov, Kirill; Bae, Youngsam; Wiberg, Dean; Peay, Chris; Challoner, Anthony; NASA Tech Briefs, February 2008; February 2008; pp. 2; In English; Original contains color illustrations
Report No.(s): NPO-40335; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2619
A proposed method of design and fabrication of vacuum-packaged microelectromechanical systems (MEMS) and of individual microelectromechanical devices involves the use of multiple internal seal rings (MISRs) in conjunction with vias (through holes plated with metal for electrical contacts). The proposed method is compatible with mass production in a wafer-level fabrication process, in which the dozens of MEMS or individual microelectromechanical devices on a typical wafer are simultaneously vacuum packaged by bonding a capping wafer before the devices are singulated (cut apart by use of a dicing saw). In addition to being compatible with mass production, the proposed method would eliminate the need for some complex and expensive production steps and would yield more reliable vacuum seals. Conventionally, each MEMS or individual microelectromechanical device is fabricated as one of many identical units on a device wafer. Vacuum packaging is accomplished by bonding the device wafer to a capping wafer with metal seal rings (one ring surrounding each unit) that have been formed on the capping wafer. The electrical leads of each unit are laid out on what would otherwise be a flat surface of the device wafer, against which the seal ring is to be pressed for sealing. The resulting pattern of metal lines and their insulating oxide coverings presents a very rough and uneven surface, upon which it is difficult to pattern the sealing metal. Consequently, the seal is prone to leakage unless additional costly and complex planarization steps are performed before patterning the seal ring and bonding the wafers.
Author
MICROELECTROMECHANICAL SYSTEMS; ELECTRIC CONDUCTORS; FLAT SURFACES; VACUUM SYSTEMS; PACKAGING; SEALING; BONDING
20090020525 California Inst. of Tech., Pasadena, CA, United States
Compact Two-Dimensional Spectrometer Optics
Hong, John; NASA Tech Briefs, February 2008; February 2008; pp. 2; In English
Report No.(s): NPO-42431; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2622
The figure is a simplified depiction of a proposed spectrometer optical unit that would be suitable for incorporation into a remote-sensing instrumentation system. Relative to prior spectrometer optical assemblies, this unit would be compact and simple, largely by virtue of its predominantly two-dimensional character. The proposed unit would be a combination of two optical components. One component would be an arrayed-waveguide grating (AWG) an integrated-optics device, developed for use in wavelength multiplexing in telecommunications. The other component would be a diffraction grating superimposed on part of the AWG. The function of an AWG is conceptually simple. Input light propagates along a single-mode optical waveguide to a point where it is split to propagate along some number (N) of side-by-side waveguides. The lengths of the optical paths along these waveguides differ such that, considering the paths in a sequence proceeding across the array of waveguides, the path length increases linearly. These waveguides launch quasi-free-space waves into a planar waveguide-coupling region. The waves propagate through this region to interfere onto an array of output waveguides. Through proper choice of key design parameters (waveguide lengths, size and shape of the waveguide coupling region, and lateral distances between waveguides), one can cause the input light to be channeled into wavelength bins nominally corresponding to the output waveguides.
Author
OPTICAL WAVEGUIDES; INTEGRATED OPTICS; SPECTROMETERS; WAVEGUIDES; OPTICAL PATHS; REMOTE SENSING; DESIGN ANALYSIS
20090020526 Mississippi State Univ., MS, United States
Improved Measurement of B(sub 22) of Macromolecules in a Flow Cell
Wilson, Wilbur; Fanguy, Joseph; Holman, Steven; Guo, Bin; NASA Tech Briefs, February 2008; February 2008; pp. 7-; In English
Report No.(s): MFS-32536-1; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2601
An improved apparatus has been invented for use in determining the osmotic second virial coefficient of macromolecules in solution. In a typical intended application, the macromolecules would be, more specifically, protein molecules, and the protein solution would be pumped through a flow cell to investigate the physical and chemical conditions that affect crystallization of the protein in question. Some background information is prerequisite to a meaningful description of the novel aspects of this apparatus. A method of determining B22 from simultaneous measurements of the static transmittance (taken as an indication of concentration) and static scattering of light from the same location in a flowing protein solution was published in 2004. The apparatus used to implement the method at that time included a dual-detector flow cell, which had two drawbacks: a) The amount of protein required for analysis of each solution condition was of the order of a milligram - far too large a quantity for a high-throughput analysis system, for which microgram or even nanogram quantities of protein per analysis are desirable. b) The design of flow cell was such that two light sources were used to probe different regions of the flowing solution. Consequently, the apparatus did not afford simultaneous measurements at the same location in the solution and, hence, did not guarantee an accurate determination of B22.
Author
PROTEIN CRYSTAL GROWTH; LIGHT SOURCES; MACROMOLECULES; PROTEINS; LIGHT SCATTERING
20090020527 California Inst. of Tech., Pasadena, CA, United States
Increasing Discharge Capacities of Li-(CF)(sub n) Cells
Whitacre, Jay; West, William; NASA Tech Briefs, February 2008; February 2008; pp. 1; In English; Original contains color illustrations
Report No.(s): NPO-42346; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2608
An electrolyte additive has shown promise as a means of increasing the sustainable rates of discharge and, hence, the discharge capacities, of lithiumpoly(carbon monofluoride) electrochemical power cells. Lithium-poly(carbon monofluoride) [Li-(CF)n] cells and batteries offer very high specific energies practical values of about 600 W.h/g and a theoretical maximum value of 2,180 W.h/kg. However, because Li-(CF)n cells and batteries cannot withstand discharge at high rates, they have been relegated to niche applications that involve very low discharge currents over times of the order of hundreds to thousands of hours. Increasing the discharge capacities of Li- (CF)n batteries while maintaining high practical levels of specific energy would open new applications for these batteries. During the discharge of a Li-(CF)n cell, one of the electrochemical reactions causes LiF to precipitate at the cathode. LiF is almost completely insoluble in most non-aqueous solvents, including those used in the electrolyte solutions of Li-(CF)n cells. LiF is electrochemically inactive and can block the desired transport of ions at the cathode, and, hence, the precipitation of LiF can form an ever-thickening film on the cathode that limits the rate of discharge.
Author
ELECTRIC POWER SUPPLIES; ELECTRIC BATTERIES; PRECIPITATES; SOLVENTS; LOW CURRENTS
20090020528 California Inst. of Tech., Pasadena, CA, United States
Dot-in-Well Quantum-Dot Infrared Photodetectors
Gunapala, Sarath; Bandara, Sumith; Ting, David; Hill, cory; Liu, John; Mumolo, Jason; Chang, Yia Chung; et al.; NASA Tech Briefs, February 2008; February 2008; pp. 1; In English; Original contains color illustrations
Report No.(s): NPO-42362; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/2606
Dot-in-well (DWELL) quantum-dot infrared photodetectors (QDIPs) [DWELL-QDIPs] are subjects of research as potentially superior alternatives to prior QDIPs. Heretofore, there has not existed a reliable method for fabricating quantum dots (QDs) having precise, repeatable dimensions. This lack has constituted an obstacle to the development of uniform, high-performance, wavelength-tailorable QDIPs and of focal-plane arrays (FPAs) of such QDIPs. However, techniques for fabricating quantum-well infrared photodetectors (QWIPs) having multiple-quantum- well (MQW) structures are now well established. In the present research on DWELL-QDIPs, the arts of fabrication of QDs and QWIPs are combined with a view toward overcoming the deficiencies of prior QDIPs. The longer-term goal is to develop focal-plane arrays of radiationhard, highly uniform arrays of QDIPs that would exhibit high performance at wavelengths from 8 to 15 m when operated at temperatures between 150 and 200 K. Increasing quantum efficiency is the key to the development of competitive QDIP-based FPAs. Quantum efficiency can be increased by increasing the density of QDs and by enhancing infrared absorption in QD-containing material. QDIPs demonstrated thus far have consisted, variously, of InAs islands on GaAs or InAs islands in InGaAs/GaAs wells. These QDIPs have exhibited low quantum efficiencies because the numbers of QD layers (and, hence, the areal densities of QDs) have been small typically five layers in each QDIP. The number of QD layers in such a device must be thus limited to prevent the aggregation of strain in the InAs/InGaAs/GaAs non-lattice- matched material system. The approach being followed in the DWELL-QDIP research is to embed In- GaAs QDs in GaAs/AlGaAs multi-quantum- well (MQW) structures (see figure). This material system can accommodate a large number of QD layers without excessive lattice-mismatch strain and the associated degradation of photodetection properties. Hence, this material system is expected to enable achievement of greater densities of QDs and correspondingly greater quantum efficiencies. The host GaAs/AlGaAs MQW structures are highly compatible with mature fabrication processes that are now used routinely in making QWIP FPAs. The hybrid InGaAs-dot/GaAs/AlGaAs-well system also offers design advantages in that the effects of variability of dot size can be partly compensated by engineering quantum-well sizes, which can be controlled precisely.
Author
QUANTUM WELLS; QUANTUM WELL INFRARED PHOTODETECTORS; QUANTUM DOTS; ALUMINUM GALLIUM ARSENIDES; INDIUM GALLIUM ARSENIDES; INFRARED RADIATION; SEMICONDUCTORS (MATERIALS)
20090020529 NASA Marshall Space Flight Center, Huntsville, AL, United States
Ares I-X Flight Test--The Future Begins Here
Davis, Stephan R.; Robinson, Kimberly F.; September 29, 2008; In English; International Astronautical Conference, 29 Sep. - 3 Oct. 2008, Glasgow, United Kingdom; Original contains color illustrations
Report No.(s): IAC-08-D2.6.6; MSFC-2110; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090020529
In less than one year, the National Aeronautics and Space Administration (NASA) will launch the Ares I-X mission. This will be the first flight of the Ares I crew launch vehicle, which, together with the Ares V cargo launch vehicle, will send humans to the Moon and beyond. Personnel from the Ares I-X Mission Management Office (MMO) are finalizing designs and fabricating vehicle hardware for a 2009 launch. Ares I-X will be a suborbital development flight test that will gather critical data about the flight dynamics of the integrated launch vehicle stack; understand how to control its roll during flight; better characterize the severe stage separation environments that the upper stage engine will experience during future flights; and demonstrate the first stage recovery system. NASA also will modify the launch infrastructure and ground and mission operations. The Ares I-X Flight Test Vehicle (FTV) will incorporate flight and mockup hardware similar in mass and weight to the operational vehicle. It will be powered by a four-segment Solid Rocket Booster (SRB), which is currently in Shuttle inventory, and will include a fifth spacer segment and new forward structures to make the booster approximately the same size and weight as the five-segment SRB. The Ares I-X flight profile will closely approximate the flight conditions that the Ares I will experience through Mach 4.5, up to approximately 130,000 feet (39,600 meters (m)) and through maximum dynamic pressure ('Max Q') of approximately 800 pounds per square foot (38.3 kilopascals (kPa)). Data from the Ares I-X flight will support the Ares I Critical Design Review (CDR), scheduled for 2010. Work continues on Ares I-X design and hardware fabrication. All of the individual elements are undergoing CDRs, followed by a two-part integrated vehicle CDR in March and July 2008. The various hardware elements are on schedule to begin deliveries to Kennedy Space Center (KSC) in early September 2008. Ares I-X is the first step in the long journey to the Moon and farther destinations. This suborbital test will be NASA's first flight of a new human-rated launch vehicle in more than a generation. This promises to be an exciting time for NASA and the nation, as we reach for new goals in space exploration. A visual presentation is included.
Author
ARES 1 LAUNCH VEHICLE; FLIGHT TESTS; SPACECRAFT DESIGN; HARDWARE
20090020530 Maryland Univ., MD, United States
First Results on the High Energy Cosmic Ray Electron Spectrum from Fermi Lat
Moiseev, Alexander; May 04, 2009; In English; April's APS Meeting, 1-5 May 2009, Denver, CO, United States; Original contains color illustrations
Contract(s)/Grant(s): NNG06EO90A
Copyright; Avail.: CASI: A02, Hardcopy
This viewgraph presentation addresses energy reconstruction, electron-hadron separation, validation of Monte Carlo with flight data and an assessment of systematic errors from the Fermi Large Area Telescope.
CASI
COSMIC RAYS; ELECTRON SPECTROSCOPY; ENERGY SPECTRA; FERMI GAMMA-RAY SPACE TELESCOPE
20090020532 NASA Goddard Space Flight Center, Greenbelt, MD, United States
ATLAST: Advanced Technology Large-Aperture Space Telescope
Oegerle, William; Postman, Marc; April 21, 2009; In English; Exoplanet Missions: 2010-2020, 21-23 Apr. 2009, Pasadena, CA, United States; Original contains black and white illustrations
Copyright; Avail.: CASI: A03, Hardcopy
The technologies needed to build an affordable larger Ultraviolet/Optical Space Telescope are presented.
CASI
APERTURES; HUBBLE SPACE TELESCOPE; SPACEBORNE TELESCOPES; ULTRAVIOLET TELESCOPES; ASTROPHYSICS
20090020533 NASA, Washington, DC, United States
NASA Tech Briefs, May 2009
May 2009; In English; Original contains color illustrations
Copyright; Avail.: CASI: A04, Hardcopy
Topics covered include: Valve-"Health"-Monitoring System; Microstrip Antenna for Remote Sensing of Soil Moisture and Sea Surface Salinity; Biomedical Wireless Ambulatory Crew Monitor; Wireless Avionics Packet to Support Fault Tolerance for Flight Applications; Aerobot Autonomy Architecture; Submillimeter Confocal Imaging Active Module; Traveling-Wave Maser for 32 GHz; System Synchronizes Recordings from Separated Video Cameras; Piecewise-Planar Parabolic Reflectarray Antenna; Reducing Interference in ATC Voice Communication; EOS MLS Level 1B Data Processing, Version 2.2; Auto-Generated Semantic Processing Services; Geospatial Authentication; Maneuver Automation Software; Event Driven Messaging with Role-Based Subscriptions; Estimating Relative Positions of Outer-Space Structures; Fabricating PFPE Membranes for Capillary Electrophoresis; Linear Actuator Has Long Stroke and High Resolution; Installing a Test Tap on a Metal Battery Case; Fabricating PFPE Membranes for Microfluidic Valves and Pumps; Room-Temperature-Cured Copolymers for Lithium Battery Gel Electrolytes; Catalysts for Efficient Production of Carbon Nanotubes; Amorphous Silk Fibroin Membranes for Separation of CO2; "Zero-Mass" Noninvasive Pressure Transducers; Radial-Electric-Field Piezoelectric Diaphragm Pumps; Ejector-Enhanced, Pulsed, Pressure-Gain Combustor; Suppressing Ghost Diffraction in E-Beam-Written Gratings; Target-Tracking Camera for a Metrology System; Polarimetric Imaging using Two Photoelastic Modulators; Miniature Wide-Angle Lens for Small-Pixel Electronic Camera; Modal Filters for Infrared Interferometry; Mo(3)Sb(7-x)Te(x) for Thermoelectric Power Generation; Two-Dimensional Quantum Model of a Nanotransistor; Scanning Miniature Microscopes without Lenses; Manipulating Neutral Atoms in Chip-Based Magnetic Traps; Expansion Compression Contacts for Thermoelectric Legs; Processing Electromyographic Signals to Recognize Words; Physical Principle for Generation of Randomness; DSN Beowulf Cluster-Based VLBI Correlator; Hybrid NN/SVM Computational System for Optimizing Designs; Criteria for Modeling in LES of Multicomponent Fuel Flow; Computerized Machine for Cutting Space Shuttle Thermal Tiles; Orbiting Depot and Reusable Lander for Lunar Transportation; FPGA-Based Networked Phasemeter for a Heterodyne Interferometer; Aquarius Digital Processing Unit; Three-Dimensional Optical Coherence Tomography; Benchtop Antigen Detection Technique using Nanofiltration and Fluorescent Dyes; Isolation of Precursor Cells from Waste Solid Fat Tissue; Identification of Bacteria and Determination of Biological Indicators; Further Development of Scaffolds for Regeneration of Nerves; Chemically Assisted Photocatalytic Oxidation System; Use of Atomic Oxygen for Increased Water Contact Angles of Various Polymers for Biomedical Applications; Crashworthy Seats Would Afford Superior Protection; Open-Access, Low-Magnetic-Field MRI System for Lung Research; Microfluidic Mixing Technology for a Universal Health Sensor; Microfluidic Extraction of Biomarkers using Water as Solvent; Microwell Arrays for Studying Many Individual Cells; Droplet-Based Production of Liposomes; and Identifying and Inactivating Bacterial Spores
Author
AIR TRAFFIC CONTROL; ANTENNA ARRAYS; CARBON NANOTUBES; COMPUTER INFORMATION SECURITY; DATA PROCESSING; DEEP SPACE NETWORK; ELECTRIC BATTERIES; ELECTROPHORESIS; FIELD-PROGRAMMABLE GATE ARRAYS; HETERODYNING; INFRARED INTERFEROMETERS; MICROWAVE LANDING SYSTEMS; NANOSTRUCTURE GROWTH; NASA PROGRAMS; VERY LONG BASE INTERFEROMETRY
20090020534 NASA Ames Research Center, Moffett Field, CA, United States
Hybrid NN/SVM Computational System for Optimizing Designs
Rai, Man Mohan; NASA Tech Briefs, May 2009; May 2009; pp. 39-4; In English; Original contains color illustrations
Report No.(s): ARC-14586; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/5193
A computational method and system based on a hybrid of an artificial neural network (NN) and a support vector machine (SVM) (see figure) has been conceived as a means of maximizing or minimizing an objective function, optionally subject to one or more constraints. Such maximization or minimization could be performed, for example, to optimize solve a data-regression or data-classification problem or to optimize a design associated with a response function. A response function can be considered as a subset of a response surface, which is a surface in a vector space of design and performance parameters. A typical example of a design problem that the method and system can be used to solve is that of an airfoil, for which a response function could be the spatial distribution of pressure over the airfoil. In this example, the response surface would describe the pressure distribution as a function of the operating conditions and the geometric parameters of the airfoil. The use of NNs to analyze physical objects in order to optimize their responses under specified physical conditions is well known. NN analysis is suitable for multidimensional interpolation of data that lack structure and enables the representation and optimization of a succession of numerical solutions of increasing complexity or increasing fidelity to the real world. NN analysis is especially useful in helping to satisfy multiple design objectives. Feedforward NNs can be used to make estimates based on nonlinear mathematical models. One difficulty associated with use of a feedforward NN arises from the need for nonlinear optimization to determine connection weights among input, intermediate, and output variables. It can be very expensive to train an NN in cases in which it is necessary to model large amounts of information. Less widely known (in comparison with NNs) are support vector machines (SVMs), which were originally applied in statistical learning theory. In terms that are necessarily oversimplified to fit the scope of this article, an SVM can be characterized as an algorithm that (1) effects a nonlinear mapping of input vectors into a higher-dimensional feature space and (2) involves a dual formulation of governing equations and constraints. One advantageous feature of the SVM approach is that an objective function (which one seeks to minimize to obtain coefficients that define an SVM mathematical model) is convex, so that unlike in the cases of many NN models, any local minimum of an SVM model is also a global minimum.
Author
DESIGN ANALYSIS; OPTIMIZATION; INTERPOLATION; VECTOR SPACES; NEURAL NETS; FEEDFORWARD CONTROL; STATISTICAL ANALYSIS; NUMERICAL ANALYSIS; CLASSIFICATIONS
20090020535 California Inst. of Tech., Pasadena, CA, United States
Target-Tracking Camera for a Metrology System
Liebe, Carl; Bartman, Randall; Chapsky, Jacob; Abramovici, Alexander; Brown, David; NASA Tech Briefs, May 2009; May 2009; pp. 28-2; In English; Original contains color illustrations
Report No.(s): NPO-41466; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/5223
An analog electronic camera that is part of a metrology system measures the varying direction to a light-emitting diode that serves as a bright point target. In the original application for which the camera was developed, the metrological system is used to determine the varying relative positions of radiating elements of an airborne synthetic aperture-radar (SAR) antenna as the airplane flexes during flight; precise knowledge of the relative positions as a function of time is needed for processing SAR readings. It has been common metrology system practice to measure the varying direction to a bright target by use of an electronic camera of the charge-coupled-device or active-pixel-sensor type. A major disadvantage of this practice arises from the necessity of reading out and digitizing the outputs from a large number of pixels and processing the resulting digital values in a computer to determine the centroid of a target: Because of the time taken by the readout, digitization, and computation, the update rate is limited to tens of hertz. In contrast, the analog nature of the present camera makes it possible to achieve an update rate of hundreds of hertz, and no computer is needed to determine the centroid. The camera is based on a position-sensitive detector (PSD), which is a rectangular photodiode with output contacts at opposite ends. PSDs are usually used in triangulation for measuring small distances. PSDs are manufactured in both one- and two-dimensional versions. Because it is very difficult to calibrate two-dimensional PSDs accurately, the focal-plane sensors used in this camera are two orthogonally mounted one-dimensional PSDs.
Derived from text
CAMERAS; METROLOGY; TRACKING (POSITION); ELECTRONICS; PHOTODIODES
20090020536 California Inst. of Tech., Pasadena, CA, United States
Polarimetric Imaging using Two Photoelastic Modulators
Wang, Yu; Cunningham, Thomas; Diner, David; Davis, Edgar; Sun, Chao; Hancock, Bruce; Gutt, Gary; Zan, Jason; Raouf, Nasrat; NASA Tech Briefs, May 2009; May 2009; pp. 2; In English; Original contains color illustrations
Report No.(s): NPO-43806; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/5224
A method of polarimetric imaging, now undergoing development, involves the use of two photoelastic modulators in series, driven at equal amplitude but at different frequencies. The net effect on a beam of light is to cause (1) the direction of its polarization to rotate at the average of two excitation frequencies and (2) the amplitude of its polarization to be modulated at the beat frequency (the difference between the two excitation frequencies). The resulting modulated optical light beam is made to pass through a polarizing filter and is detected at the beat frequency, which can be chosen to equal the frame rate of an electronic camera or the rate of sampling the outputs of photodetectors in an array. The method was conceived to satisfy a need to perform highly accurate polarimetric imaging, without cross-talk between polarization channels, at frame rates of the order of tens of hertz. The use of electro-optical modulators is necessitated by a need to obtain accuracy greater than that attainable by use of static polarizing filters over separate fixed detectors. For imaging, photoelastic modulators are preferable to such other electrio-optical modulators as Kerr cells and Pockels cells in that photoelastic modulators operate at lower voltages, have greater angular acceptances, and are easier to use. Prior to the conception of the present method, polarimetric imaging at frame rates of tens of hertz using photoelastic modulators was not possible because the resonance frequencies of photoelastic modulators usually lie in the range from about 20 to about 100 kHz.
Derived from text
ELECTRO-OPTICS; IMAGING TECHNIQUES; MODULATORS; POLARIMETRY; PHOTOELASTICITY
20090020537 California Inst. of Tech., Pasadena, CA, United States
DSN Beowulf Cluster-Based VLBI Correlator
Rogstad, Stephen P.; Jongeling, Andre P.; Finley, Susan G.; White, Leslie A.; Lanyi, Gabor E.; Clark, John E.; Goodhart, Charles E.; NASA Tech Briefs, May 2009; May 2009; pp. 38-3; In English; Original contains color illustrations
Report No.(s): NPO-46279; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/5194
The NASA Deep Space Network (DSN) requires a broadband VLBI (very long baseline interferometry) correlator to process data routinely taken as part of the VLBI source Catalogue Maintenance and Enhancement task (CAT M&E) and the Time and Earth Motion Precision Observations task (TEMPO). The data provided by these measurements are a crucial ingredient in the formation of precision deep-space navigation models. In addition, a VLBI correlator is needed to provide support for other VLBI related activities for both internal and external customers. The JPL VLBI Correlator (JVC) was designed, developed, and delivered to the DSN as a successor to the legacy Block II Correlator. The JVC is a full-capability VLBI correlator that uses software processes running on multiple computers to cross-correlate two-antenna broadband noise data. Components of this new system (see Figure 1) consist of Linux PCs integrated into a Beowulf Cluster, an existing Mark5 data storage system, a RAID array, an existing software correlator package (SoftC) originally developed for Delta DOR Navigation processing, and various custom- developed software processes and scripts. Parallel processing on the JVC is achieved by assigning slave nodes of the Beowulf cluster to process separate scans in parallel until all scans have been processed. Due to the single stream sequential playback of the Mark5 data, some ramp-up time is required before all nodes can have access to required scan data. Core functions of each processing step are accomplished using optimized C programs. The coordination and execution of these programs across the cluster is accomplished using Pearl scripts, PostgreSQL commands, and a handful of miscellaneous system utilities. Mark5 data modules are loaded on Mark5 Data systems playback units, one per station. Data processing is started when the operator scans the Mark5 systems and runs a script that reads various configuration files and then creates an experiment-dependent status database used to delegate parallel tasks between nodes and storage areas (see Figure 2). This script forks into three processes: extract, translate, and correlate. Each of these processes iterates on available scan data and updates the status database as the work for each scan is completed. The extract process coordinates and monitors the transfer of data from each of the Mark5s to the Beowulf RAID storage systems. The translate process monitors and executes the data conversion processes on available scan files, and writes the translated files to the slave nodes. The correlate process monitors the execution of SoftC correlation processes on the slave nodes for scans that have completed translation. A comparison of the JVC and the legacy Block II correlator outputs reveals they are well within a formal error, and that the data are comparable with respect to their use in flight navigation. The processing speed of the JVC is improved over the Block II correlator by a factor of 4, largely due to the elimination of the reel-to-reel tape drives used in the Block II correlator.
Author
VERY LONG BASE INTERFEROMETRY; CORRELATORS; DATA CONVERSION ROUTINES; DATA SYSTEMS; DEEP SPACE NETWORK; PARALLEL PROCESSING (COMPUTERS); DATA BASES; COORDINATES; DATA PROCESSING
20090020538 California Inst. of Tech., Pasadena, CA, United States
Identification of Bacteria and Determination of Biological Indicators
Venkateswaran, Kasthuri; La Duc, Myron T.; Vaishampayan, Parag A.; NASA Tech Briefs, May 2009; May 2009; pp. 45-4; In English
Report No.(s): NPO-46221; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/5234
The ultimate goal of planetary protection research is to develop superior strategies for inactivating resistance bearing micro-organisms like Rummeli - bacillus stabekisii. By first identifying the particular physiologic pathway and/or structural component of the cell/spore that affords it such elevated tolerance, eradication regimes can then be designed to target these resistance-conferring moieties without jeopardizing the structural integrity of spacecraft hardware. Furthermore, hospitals and government agencies frequently use biological indicators to ensure the efficacy of a wide range of sterilization processes. The spores of Rummelibacillus stabekisii, which are far more resistant to many of such perturbations, could likely serve as a more significant biological indicator for potential survival than those being used currently.
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BACTERIA; MICROORGANISMS; LIFE SCIENCES; PLANETARY PROTECTION; BIOMARKERS
20090020539 California Inst. of Tech., Pasadena, CA, United States
Further Development of Scaffolds for Regeneration of Nerves
Sakamoto, Jeffrey; Tuszynski, Mark; NASA Tech Briefs, May 2009; May 2009; pp. 46-4; In English; Original contains color illustrations
Report No.(s): NPO-45303; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/5235
Progress has been made in continuing research on scaffolds for the guided growth of nerves to replace damaged ones. The scaffolds contain pores that are approximately cylindrical and parallel, with nearly uniform widths ranging from tens to hundreds of microns. At the earlier stage of development, experimental scaffolds had been made from agarose hydrogel. Such a scaffold was made in a multistep process in which poly(methyl methacrylate) [PMMA] fibers were used as templates for the pores. The process included placement of a bundle of the PMMA fibers in a tube, filling the interstices in the tube with a hot agarose solution, cooling to turn the solution into a gel, and then immersion in acetone to dissolve the PMMA fibers. The scaffolds were typically limited to about 25 pores per scaffold, square cross sections of no more than about 1.5 by 1.5 mm, and lengths of no more than about 2 mm.
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NERVES; POLYSTYRENE; POLYMETHYL METHACRYLATE; NEUROLOGY
20090020540 California Inst. of Tech., Pasadena, CA, United States
Mo(3)Sb(7-x)Te(x) for Thermoelectric Power Generation
Snyder, G. Jeffrey; Gascoin, Frank S.; Rasmussen, Julia; NASA Tech Briefs, May 2009; May 2009; pp. 31-3; In English; Original contains color illustrations
Report No.(s): NPO-43862; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/5189
Compounds having compositions of Mo(3)Sb(7-x)Te(x) (where x = 1.5 or 1.6) have been investigated as candidate thermoelectric materials. These compounds are members of a class of semiconductors that includes previously known thermoelectric materials. All of these compounds have complex crystalline and electronic structures. Through selection of chemical compositions and processing conditions, it may be possible to alter the structures to enhance or optimize thermoelectric properties.
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THERMOELECTRIC POWER GENERATION; MOLYBDENUM; TELLURIUM; SYNTHESIS (CHEMISTRY); METAL COMPOUNDS
20090020541 California Inst. of Tech., Pasadena, CA, United States
Suppressing Ghost Diffraction in E-Beam-Written Gratings
Wilson, Daniel; Backlund, Johan; NASA Tech Briefs, May 2009; May 2009; pp. 27-2; In English; Original contains color and black and white illustrations
Report No.(s): NPO-41302; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/5186
A modified scheme for electron-beam (E-beam) writing used in the fabrication of convex or concave diffraction gratings makes it possible to suppress the ghost diffraction heretofore exhibited by such gratings. Ghost diffraction is a spurious component of diffraction caused by a spurious component of grating periodicity as described below. The ghost diffraction orders appear between the main diffraction orders and are typically more intense than is the diffuse scattering from the grating. At such high intensity, ghost diffraction is the dominant source of degradation of grating performance. The pattern of a convex or concave grating is established by electron-beam writing in a resist material coating a substrate that has the desired convex or concave shape. Unfortunately, as a result of the characteristics of electrostatic deflectors used to control the electron beam, it is possible to expose only a small field - typically between 0.5 and 1.0 mm wide - at a given fixed position of the electron gun relative to the substrate. To make a grating larger than the field size, it is necessary to move the substrate to make it possible to write fields centered at different positions, so that the larger area is synthesized by "stitching" the exposed fields.
Author
GRATINGS (SPECTRA); PERIODIC VARIATIONS; ELECTRON BEAMS; ELECTROSTATICS; DIFFRACTION; DEFLECTORS; FABRICATION
20090020542 California Inst. of Tech., Pasadena, CA, United States
"Zero-Mass" Noninvasive Pressure Transducers
Hartley, Frank T.; NASA Tech Briefs, May 2009; May 2009; pp. 2; In English; Original contains black and white illustrations
Report No.(s): NPO-21194; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/5183
Extremely lightweight, compact, noninvasive, rugged, relatively inexpensive strain-gauge transducers have been developed for use in measuring pressures of fluids in tubes. These gauges were originally intended for measuring pressures of spacecraft-propulsion fluids, but they are also attractive for use in numerous terrestrial applications especially those involving fluids that are extremely chemically reactive, fluids that must be isolated for hygienic purposes, fluids that must be allowed to flow without obstruction, and fluid-containing tubes exposed to severe environments. A basic pressure transducer of this type comprises one or more pair(s) of thin-film strain gauges integral with a tube that contains the fluid of interest. Following established strain-gauge practice, the gauges in each pair are connected into opposite arms of a Wheatstone bridge (see figure). Typically, each pressure transducer includes one pair (the active pair) of strain gauges for measuring the hoop stress proportional to the pressure of the fluid in the tube and another pair (the dummy pair) of strain gauges that are nominally unstrained: The dummy gauges are mounted on a substrate that is made of the same material as that of the tube. The substrate is welded to the tube at only one spot so that stresses and strains are not coupled from the tube into the substrate. The dummy strain gauges measure neutral strains (basically, strains associated with thermal expansion), so that the neutral-strain contribution can be subtracted out of the final gauge reading.
Author
PRESSURE SENSORS; CHEMICAL REACTIONS; TRANSDUCERS; PRESSURE MEASUREMENT; MEASURING INSTRUMENTS; STRAIN GAGES; THERMAL EXPANSION
20090020543 NASA Johnson Space Center, Houston, TX, United States
Orbiting Depot and Reusable Lander for Lunar Transportation
Petro, Andrew; NASA Tech Briefs, May 2009; May 2009; pp. 4; In English
Report No.(s): MSC-24231-1; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/5199
A document describes a conceptual transportation system that would support exploratory visits by humans to locations dispersed across the surface of the Moon and provide transport of humans and cargo to sustain one or more permanent Lunar outpost. The system architecture reflects requirements to (1) minimize the amount of vehicle hardware that must be expended while maintaining high performance margins and (2) take advantage of emerging capabilities to produce propellants on the Moon while also enabling efficient operation using propellants transported from Earth. The system would include reusable single- stage lander spacecraft and a depot in a low orbit around the Moon. Each lander would have descent, landing, and ascent capabilities. A crew-taxi version of the lander would carry a pressurized crew module; a cargo version could carry a variety of cargo containers. The depot would serve as a facility for storage and for refueling with propellants delivered from Earth or propellants produced on the Moon. The depot could receive propellants and cargo sent from Earth on a variety of spacecraft. The depot could provide power and orbit maintenance for crew vehicles from Earth and could serve as a safe haven for lunar crews pending transport back to Earth.
Author
LUNAR BASES; SPACECRAFT MODULES; SPACECREWS; MAINTENANCE; CARGO
20090020544 NASA Glenn Research Center, Cleveland, OH, United States
Room-Temperature-Cured Copolymers for Lithium Battery Gel Electrolytes
Meador, Mary Ann B.; Tigelaar, Dean M.; NASA Tech Briefs, May 2009; May 2009; pp. 21-2; In English; Original contains color illustrations
Report No.(s): LEW-18205-1; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/5178
Polyimide-PEO copolymers (PEO signifies polyethylene oxide) that have branched rod-coil molecular structures and that can be cured into film form at room temperature have been invented for use as gel electrolytes for lithium-ion electric-power cells. These copolymers offer an alternative to previously patented branched rod-coil polyimides that have been considered for use as polymer electrolytes and that must be cured at a temperature of 200 C. In order to obtain sufficient conductivity for lithium ions in practical applications at and below room temperature, it is necessary to imbibe such a polymer with a suitable carbonate solvent or ionic liquid, but the high-temperature cure makes it impossible to incorporate and retain such a liquid within the polymer molecular framework. By eliminating the high-temperature cure, the present invention makes it possible to incorporate the required liquid.
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COPOLYMERS; ELECTROLYTES; GELS; LITHIUM BATTERIES; ROOM TEMPERATURE
20090020545 North Carolina State Univ., Raleigh, NC, United States
Amorphous Silk Fibroin Membranes for Separation of CO2
Aberg, Christopher M.; Patel, Anand K.; Gil, Eun Seok; Spontak, Richard J.; Hagg, May-Britt; NASA Tech Briefs, May 2009; May 2009; pp. 2; In English
Report No.(s): MSC-24032-1; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/5180
Amorphous silk fibroin has shown promise as a polymeric material derivable from natural sources for making membranes for use in removing CO2 from mixed-gas streams. For most applications of silk fibroin, for purposes other than gas separation, this material is used in its highly crystalline, nearly natural form because this form has uncommonly high tensile strength. However, the crystalline phase of silk fibroin is impermeable, making it necessary to convert the material to amorphous form to obtain the high permeability needed for gas separation. Accordingly, one aspect of the present development is a process for generating amorphous silk fibroin by treating native silk fibroin in an aqueous methanol/salt solution. The resulting material remains self-standing and can be prepared as thin film suitable for permeation testing. The permeability of this material by pure CO2 has been found to be highly improved, and its mixed-gas permeability has been found to exceed the mixed-gas permeabilities of several ultrahigh-CO2-permeable synthetic polymers. Only one of the synthetic polymers poly(trimethylsilylpropyne) [PTMSP] may be more highly permeable by CO2. PTMSP becomes unstable with time, whereas amorphous silk should not, although at the time of this reporting this has not been conclusively proven.
Author
AMORPHOUS MATERIALS; SILK; CARBON DIOXIDE; PERMEABILITY; CRYSTALLINITY; GAS MIXTURES; TENSILE STRENGTH
20090020546 California Inst. of Tech., Pasadena, CA, United States
Microfluidic Extraction of Biomarkers using Water as Solvent
Amashukeli, Xenia; Manohara, Harish; Chattopadhyay, Goutam; Mehdi, Imran; NASA Tech Briefs, May 2009; May 2009; pp. 50-5; In English; Original contains color illustrations
Report No.(s): NPO-46150; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://www.techbriefs.com/component/content/article/5243
A proposed device, denoted a miniature microfluidic biomarker extractor (mu-EX), would extract trace amounts of chemicals of interest from samples, such as soils and rocks. Traditionally, such extractions are performed on a large scale with hazardous organic solvents; each solvent capable of dissolving only those molecules lying within narrow ranges of specific chemical and physical characteristics that notably include volatility, electric charge, and polarity. In contrast, in the mu-EX, extractions could be performed by use of small amounts (typically between 0.1 and 100 L) of water as a universal solvent. As a rule of thumb, in order to enable solvation and extraction of molecules, it is necessary to use solvents that have polarity sufficiently close to the polarity of the target molecules. The mu-EX would make selection of specific organic solvents unnecessary, because mu-EX would exploit a unique property of liquid water: the possibility of tuning its polarity to match the polarity of organic solvents appropriate for extraction of molecules of interest. The change of the permittivity of water would be achieved by exploiting interactions between the translational states of water molecules and an imposed electromagnetic field in the frequency range of 300 to 600 GHz. On a molecular level, these interactions w | |
