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The products of the pyrolysis reactions of perfluoropropane, perfluoroethane, and carbon tetrafluoride in an Inconel bomb are described. The values for the energy of activation and frequency factor for the first-order pyrolysis reactions are respectively: (1) 80 kcal. per mole and 2x10(exp14) sec.(exp-1) for perfluoropropane; (2) 53 kcal. per mole and 3x10(exp7) sec.(exp-1) for perfluoroethane; and (3) 96 kcal. per mole and 4x10(exp13) sec.(exp-1) for carbon tetrafluoride.
Topic: NASA Technical Reports Server (NTRS)
The successful launch of a space shuttle vehicle depends on the proper operation of two tail service masts (TSMs). Reliable TSM operation is assured through a comprehensive design, development, and testing program. The results of the concept verification test (CVT) and the resulting impact on prototype TSM design are presented. The design criteria are outlined, and the proposed prototype TSM tests are described.
Topics: NASA Technical Reports Server (NTRS), CHECKOUT, SPACE SHUTTLES, TAIL ASSEMBLIES, AEROSPACE...
The capabilities of several astronomical interferomenter system concepts are assessed and the effects of the Earth's atmosphere on astrometric precision are examined in detail. Included is an examination of the use of small aperture interferometry to detect planets in binary star systems. It is estimated that, for differential astrometric observation, an amplitude interferometer having two separate telescopes should permit observations of stars as faint as 14th magnitude and a positional...
Topics: NASA Technical Reports Server (NTRS), ASTROMETRY, EXTRASOLAR PLANETS, PLANETARY SYSTEMS,...
The Deep Space Station 13 26-meter antenna with the second generation S/X feedcone was tested to determine the dual S- and X-band (2.1 to 2.3 GHz and 7.1 to 8.5 GHz) transmit and receive performance. Measurements were conducted using the 20 kW transmitters at S- and X-band while simultaneously receiving S- and X-band. This system proved to be very quiet compared with the other DSN antennas. Under normal tracking configurations, no noise burst or intermodulation product (IMP) activity was...
Topics: NASA Technical Reports Server (NTRS), DOWNLINKING, NOISE REDUCTION, SIGNAL RECEPTION, SIGNAL...
We finished the material development of Level 1, Level 2 and most of Level 3. We created three new galleries, one of streaming videos enabling the user to select his/her appropriate speed of Internet connectivity for better performance. The second gallery on NASA's X-series aircraft and the third is on F-series aircraft. We also completed the placement and activation of all thirteen kiosks. We added one more kiosk over the number suggested in the proposal at Baker Aviation High School - a Dade...
Topics: NASA Technical Reports Server (NTRS), AERONAUTICAL ENGINEERING, LABORATORY EQUIPMENT, LABORATORIES,...
The development of next generation systems often carries with it the promise of improved performance, greater reliability, and reduced operational costs. These expectations arise from the use of novel designs, new materials, advanced integration and production technologies intended for functionality replacing the previous generation. However, the novelty of these nascent technologies is accompanied by lack of operational experience and, in many cases, no actual testing as well. Therefore some...
Topics: NASA Technical Reports Server (NTRS), FORECASTING, RELIABILITY, SYSTEMS ENGINEERING, DESIGN...
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Finite element models are often developed for load validation, structural certification, response predictions, and to study alternate design concepts. In rare occasions, models developed with a nominal set of parameters agree with experimental data without the need to update parameter values. Today, model updating is generally heuristic and often performed by a skilled analyst with in-depth understanding of the model assumptions. Parameter uncertainties play a key role in understanding the...
Topics: NASA Technical Reports Server (NTRS), FINITE ELEMENT METHOD, PROBABILITY THEORY, FLUTTER ANALYSIS,...
A new three-dimensional, full-field analysis technique has been developed for industrial and space applications. Stereo Imaging Velocimetry (SIV) will provide full-field analysis for three-dimensional flow data from any optically transparent fluid that can be seeded with tracer particles. The goal of SIV is to provide a means to measure three-dimensional fluid velocities quantitatively and qualitatively at many points. SIV is applicable to any optically transparent fluid experiment. Except for...
Topics: NASA Technical Reports Server (NTRS), VELOCITY MEASUREMENT, IMAGING TECHNIQUES, FLUID FLOW,...
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The UNO Aviation Institute Monograph Series began in 1994 as a key component of the education outreach and information transfer missions of the Aviation Institute and the NASA Nebraska Space Grant & EPSCoR Programs. The series is an outlet for aviation materials to be indexed and disseminated through an efficient medium. Publications are welcome in all aspects of aviation. Publication formats may include, but are not limited to, conference proceedings, bibliographies, research reports,...
Topics: NASA Technical Reports Server (NTRS), INFORMATION TRANSFER, NASA PROGRAMS, EDUCATION,...
The troposphere above the West Antarctic Ice Sheet (WAIS) was sampled for hydroperoxides at 21 locations during 2-month-long summer traverses from 2000 to 2002, as part of US ITASE (International Transantarctic Scientific Expedition). First time quantitative measurements using an HPLC method showed that methylhydroperoxide (MHP) is the only important organic hydroperoxide occurring in the Antarctic troposphere, and that it is found at levels ten times those previously predicted by photochemical...
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC COMPOSITION, HYDROGEN PEROXIDE, PHOTOCHEMICAL...
NASA Marshall Space Flight Center (MSFC) is well known for its contributions to large ascent propulsion systems such as the Saturn V and the Space Shuttle. This paper highlights a lesser known but equally rich side of MSFC - its heritage in spacecraft chemical propulsion systems and its current capabilities for in-space propulsion system development and chemical propulsion research. The historical narrative describes the efforts associated with developing upper-stage main propulsion systems...
Topics: NASA Technical Reports Server (NTRS), SPACECRAFT PROPULSION, PROPULSION SYSTEM CONFIGURATIONS,...
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by NASA Technical Reports Server (NTRS)
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Methods and tool for simultaneously forming a bore in a work piece and forming a series of threads in said bore. In an embodiment, the tool has a predetermined axial length, a proximal end, and a distal end, said tool comprising: a shank located at said proximal end; a pilot drill portion located at said distal end; and a mill portion intermediately disposed between said shank and said pilot drill portion. The mill portion is comprised of at least two drill-tap sections of predetermined axial...
Topics: NASA Technical Reports Server (NTRS), CAVITIES, THREADS, DRILLS, DRILL BITS, PATENTS, Pettit,...
Two protuberance designs were modeled in the channel nozzle of the NASA Johnson Space Center Atmospheric Reentry Materials and Structures Facility with the Data-Parallel Line Relaxation computational fluid dynamics code. The heating on the protuberance was compared to nominal baseline heating at a single fixed arc-jet condition in order to obtain heating augmentation factors for flight traceability in the Boundary Layer Transition Flight Experiment on Space Shuttle Orbiter flights STS-119 and...
Topics: NASA Technical Reports Server (NTRS), BOUNDARY LAYER TRANSITION, PROTUBERANCES, NOZZLE DESIGN,...
Quieter working environments for astronauts are needed if future long-duration space exploration missions are to be safe and productive. Ventilation and payload cooling fans are known to be dominant sources of noise, with the International Space Station being a good case in point. To address this issue in a cost-effective way, early attention to fan design, selection, and installation has been recommended. Toward that end, NASA has begun to investigate the potential for small-fan noise...
Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC NOISE, VENTILATION FANS, LONG DURATION SPACE...
This paper reviews the theoretical foundation and computational mechanics aspects of the recently developed shear-deformation theory, called the Refined Zigzag Theory (RZT). The theory is based on a multi-scale formalism in which an equivalent single-layer plate theory is refined with a robust set of zigzag local layer displacements that are free of the usual deficiencies found in common plate theories with zigzag kinematics. In the RZT, first-order shear-deformation plate theory is used as the...
Topics: NASA Technical Reports Server (NTRS), LAMINATES, COMPOSITE STRUCTURES, BEAMS (SUPPORTS), SANDWICH...
NASA's future robotic missions to Venus and outer planets, namely, Saturn, Uranus, Neptune, result in extremely high entry conditions that exceed the capabilities of current mid-density ablators (PICA or Avcoat). Therefore mission planners assume the use of a fully dense carbon phenolic heat shield similar to what was flown on Pioneer Venus and Galileo. Carbon phenolic (CP) is a robust Thermal Protection System (TPS) however its high density and thermal conductivity constrain mission planners...
Topics: NASA Technical Reports Server (NTRS), WOVEN COMPOSITES, THERMAL PROTECTION, HEAT SHIELDING, SPACE...
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Gas House Autonomous System Monitoring (GHASM) will employ Integrated System Health Monitoring (ISHM) of cryogenic fluids in the High Pressure Gas Facility at Stennis Space Center. The preliminary focus of development incorporates the passive monitoring and eventual commanding of the Nitrogen System. ISHM offers generic system awareness, adept at using concepts rather than specific error cases. As an enabler for autonomy, ISHM provides capabilities inclusive of anomaly detection, diagnosis, and...
Topics: NASA Technical Reports Server (NTRS), SYSTEMS HEALTH MONITORING, GAS ANALYSIS, AEROSPACE...
The application of cellular arrays to NASA missions was studied. Cellular arrays are iterative logical and memory structures which can be programmed to accomplish a wide variety of logical tasks. Used in long-duration space missions, spare cellular arrays can be remotely programmed to replace faulty logical subsystems as the need arises.
Topics: NASA Technical Reports Server (NTRS), ITERATION, LOGIC CIRCUITS, SOLAR CELLS, PLASTIC MEMORY, SOLAR...
Flight control and procedural task skill degradation, and the effectiveness of retraining methods were evaluated for a simulated space vehicle approach and landing under instrument and visual flight conditions. Fifteen experienced pilots were trained and then tested after 4 months either without the benefits of practice or with static rehearsal, dynamic rehearsal or with dynamic warmup practice. Performance on both the flight control and procedure tasks degraded significantly after 4 months....
Topics: NASA Technical Reports Server (NTRS), APPROACH CONTROL, CUES, PILOT TRAINING, SPACECRAFT LANDING,...
The scientific and engineering findings are presented of the feasibility study for the use of a YF-12 aircraft as a scientific instrument platform for observing the 1970 solar eclipse. Included in the report is the computer program documentation of the solar eclipse determination; summary data on SR-71A type aircraft capabilities and limitations as an observing platform for solar eclipses; and the recordings of an informal conference on observations of solar eclipses using SR-71A type aircraft.
Topics: NASA Technical Reports Server (NTRS), FLYING PLATFORMS, JET AIRCRAFT, SOLAR ECLIPSES, COMPUTER...
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ERTS-1 imagery clearly shows a 50-mile wide tectonic zone across Southern California oriented about 15 deg to the structures of the Transverse Ranges or with an azimuth of 70 deg. The zone is delineated on the imagery by terrian alignments and vegetational differences. A previously undisclosed tectonic lineament extends across the Mojave Desert and appears as a line of crustal upwarping. Pressure which would have caused this plus the occurrence of many thrust faults with the 70 deg azimuth...
Topics: NASA Technical Reports Server (NTRS), GEOLOGICAL FAULTS, LANDSAT 1, SOUTHERN CALIFORNIA, TECTONICS,...
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by NASA Technical Reports Server (NTRS)
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An improved solar energy collection system, having enhanced energy collection and conversion capabilities, is delineated. The system is characterized by a plurality of receivers suspended above a heliostat field comprising a multiplicity of reflector surfaces, each being adapted to direct a concentrated beam of solar energy to illuminate a target surface for a given receiver. A magnitude of efficiency, suitable for effectively competing with systems employed in collecting and converting energy...
Topics: NASA Technical Reports Server (NTRS), ENERGY CONVERSION, ENERGY TECHNOLOGY, SOLAR COLLECTORS, SOLAR...
The author has identified the following significant results. Evaluation of LANDSAT imagery indicates severe limitations in its utility for surface mine land studies. Image stripping resulting from unequal detector response on satellite degrades the image quality to the extent that images of scales larger than 1:125,000 are of limited value for manual interpretation. Computer processing of LANDSAT data to improve image quality is essential; the removal of scanline stripping and enhancement of...
Topics: NASA Technical Reports Server (NTRS), COAL, PENNSYLVANIA, RECLAMATION, STRIP MINING,...
Test procedures used during the performance of an evaluation program are presented. The test program was conducted to obtain the following performance data and information on the solar collector. (1) thermal performance data under outdoor conditions; (2) structural behavior of collector under static conditions; (3) effects of long term exposure to material weathering elements. The solargenics is a liquid, single-glazed, flat plate collector. Approximate dimensions of each collector are 240...
Topics: NASA Technical Reports Server (NTRS), PERFORMANCE TESTS, SOLAR COLLECTORS, THERMODYNAMIC...
An analytical model for separated airfoil flows is presented which is based on experimentally observed physical phenomena. These include a free stagnation point aft of the airfoil and a standing vortex in the separated region. A computer program is described which iteratively matches the outer potential flow, the airfoil turbulent boundary layer, the separated jet entrainment, mass conservation in the separated bubble, and the rear stagnation pressure. Separation location and pressure are not...
Topics: NASA Technical Reports Server (NTRS), AIRFOIL PROFILES, FLOW EQUATIONS, LOW SPEED, SEPARATED FLOW,...
A leading edge flap design for highly swept wings, called a vortex flap, was tested on an arrow wing model in a low speed wind tunnel. A vortex flap differs from a conventional plain flap in that it has a leading edge tab which is counterdeflected from the main portion of the flap. This results in intentional separation at the flap leading edge, causing a vortex to form and lie on the flap. By trapping this vortex, the vortex flap can result in significantly improved wing flow characteristics...
Topics: NASA Technical Reports Server (NTRS), ARROW WINGS, LEADING EDGE FLAPS, LOW SPEED WIND TUNNELS,...
A large concave microwave mirror near the transmitter can magnify the apparent size of the Earth as seen from a phased array, and vice versa, permitting a small phased array to be coupled to a small rectenna while preserving the transmission efficiency (the reflection loss is slight) and peak power densities characteristic of the reference system. This augmentation of the phased array aperture with a large mirror gives the system greater resolution (in the optical sense), and opens new degrees...
Topics: NASA Technical Reports Server (NTRS), MICROWAVE TRANSMISSION, PHASED ARRAYS, SOLAR POWER...
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A simple proton damage model for GaAs solar cells is derived and compared to experimental values of change in short circuit currents. The recombination cross section associated with the defects was determined from the experimental comparison to be approximately 1.2 x 10 to the -13th power sq cm in fair agreement with values determined from the deep level transient spectroscopy technique.
Topics: NASA Technical Reports Server (NTRS), ELECTRIC CURRENT, GALLIUM ARSENIDES, PROTON DAMAGE, SHORT...
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The rolling-element fatigue life of AMS 5900 12.7-mm (1/2-in.) dia was determined in five-ball fatigue testers. The 10% life with the warm headed AMS 5900 balls was equivalent to that of AMS 5749 and over eight times that of AISI M-50. The AMS balls fabricated by cold heading had small surface cracks which initiated fatigue spalls where these cracks were crossed by running tracks. The cold-headed AMS 5900 balls had a 10% fatigue life an order of magnitude less than that of the warm headed balls...
Topics: NASA Technical Reports Server (NTRS), BALL BEARINGS, FATIGUE LIFE, FATIGUE TESTS, STAINLESS STEELS,...
An iterative algorithm for the Helmholtz equation is presented. This scheme was based on the preconditioned conjugate gradient method for the normal equations. The preconditioning is one cycle of a multigrid method for the discrete Laplacian. The smoothing algorithm is red-black Gauss-Seidel and is constructed so it is a symmetric operator. The total number of iterations needed by the algorithm is independent of h. By varying the number of grids, the number of iterations depends only weakly on...
Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, DIRICHLET PROBLEM, HELMHOLTZ EQUATIONS, ITERATIVE...
Preliminary work with aperture synthesis concepts for EOS is reported. The effects of nonvanishing bandwidths on image reconstruction in aperture synthesis system was studied. It is found that nonvanishing bandwidths introduce errors in off-axis pixels when naive Fourier processing is used. The net effect is for bandwidth to limit sensor field-of-view. To quantify this effect a computer program was written which is documented. Example runs are included which illustrate the resultant radiometric...
Topics: NASA Technical Reports Server (NTRS), BANDWIDTH, EARTH OBSERVING SYSTEM (EOS), FIELD OF VIEW,...
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The use of Artificial Intelligence (AI) and the programming language Ada to help a satellite recover from selected failures that could lead to mission failure are described. An unmanned satellite will have a separate AI subsystem running in parallel with the normal satellite subsystems. A satellite monitoring subsystem (SMS), under the control of a blackboard system, will continuously monitor selected satellite subsystems to become alert to any actual or potential problems. In the case of loss...
Topics: NASA Technical Reports Server (NTRS), ADA (PROGRAMMING LANGUAGE), ARTIFICIAL INTELLIGENCE,...
A growing amount of observational and theoretical evidence suggests that most main sequence stars are surrounded by disks of cometary material. The dust production by comets in such disks is investigated when the central stars evolve up the red giant and asymptotic giant branch (AGB). Once released, the dust is ablated and accelerated by the gas outflow and the fragments become the seeds necessary for condensation of the gas. The origin of the requisite seeds has presented a well known problem...
Topics: NASA Technical Reports Server (NTRS), ASYMPTOTIC GIANT BRANCH STARS, COMETS, CONDENSATION, COSMIC...
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Few of the heart-lung interactions that are discussed have been studied in any detail in the aerospace environment, but is seems that many such interactions must occur in the setting of altered accelerative loadings and pressure breathing. That few investigations are in progress suggests that clinical and academic laboratory investigators and aerospace organizations are further apart than during the pioneering work on pressure breathing and acceleration tolerance in the 1940s. The purpose is to...
Topics: NASA Technical Reports Server (NTRS), AEROSPACE ENVIRONMENTS, AEROSPACE MEDICINE, GRAVITATIONAL...
An interactive 3D grid generation code, Turbomachinery Interactive Grid genERation (TIGER), was developed for general turbomachinery configurations. TIGER features the automatic generation of multi-block structured grids around multiple blade rows for either internal, external, or internal-external turbomachinery flow fields. Utilization of the Bezier's curves achieves a smooth grid and better orthogonality. TIGER generates the algebraic grid automatically based on geometric information...
Topics: NASA Technical Reports Server (NTRS), CURVES (GEOMETRY), GRID GENERATION (MATHEMATICS),...
As part of a cooperative research program between NASA, McDonnell Douglas Corporation, and Wright Research and Development Center, a flow field investigation was conducted on a 7.52 percent scale windtunnel model of an advanced fighter aircraft design. The investigation was conducted in the Langley 16 ft Transonic Tunnel at Mach numbers of 0.6, 0.9, and 1.2. Angle of attack was varied from -4 degrees to 30 degrees and the model was tested at angles of sideslip of 0, 5, and -5 degrees. Data for...
Topics: NASA Technical Reports Server (NTRS), DELTA WINGS, FIGHTER AIRCRAFT, FLOW DISTRIBUTION, SUBSONIC...
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The acoustically based fetal heart rate monitor permits an expectant mother to perform the fetal Non-Stress Test in her home. The potential market would include the one million U.S. pregnancies per year requiring this type of prenatal surveillance. The monitor uses polyvinylidene fluoride (PVF2) piezoelectric polymer film for the acoustic sensors, which are mounted in a seven-element array on a cummerbund. Evaluation of the sensor ouput signals utilizes a digital signal processor, which...
Topics: NASA Technical Reports Server (NTRS), ACOUSTICS, FETUSES, HEART RATE, MONITORS, PIEZOELECTRICITY,...
A reexamination of Dressler's (1980) sample of nearly 6000 galaxies in 55 clusters shows that the morphology-clustercentric radius relation is more fundamental than the morphology-local density relation. This conclusion is supported by improved correlations when the projected clustercentric radius is used as the independent parameter, and by a comparison of galaxies with the same normalized clustercentric radii by different values of the projected local density.
Topics: NASA Technical Reports Server (NTRS), ELLIPTICAL GALAXIES, GALACTIC CLUSTERS, GALACTIC EVOLUTION,...
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by NASA Technical Reports Server (NTRS)
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Tropical Kelvin waves have been observed previously in ozone mixing ratio data from the SBUV (Solar Backscatter Ultraviolet) and LIMS (Limb Infrared Monitor of the Stratosphere) instruments on board the Nimbus-7 satellite. Kelvin wave features in total column ozone, using version 6 data from the Total Ozone Mapping Spectrometer (TOMS) instrument (also on board Nimbus-7) are investigated. Results show eastward-propagating zonal waves 1-2 with periods approximately 5-15 days, amplitudes...
Topics: NASA Technical Reports Server (NTRS), KELVIN WAVES, OZONE, STRATOSPHERE, TOTAL OZONE MAPPING...
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As the use of fuzzy set theory continues to grow, there is an increased need for methodologies and formalisms to manipulate obtained fuzzy subsets. Concepts involving relative position of fuzzy patterns are acknowledged as being of high importance in many areas. In this paper, we present an approach based on the concept of dominance in fuzzy set theory for modelling relative positions among fuzzy subsets of a plane. In particular, we define the following spatial relations: to the left (right),...
Topics: NASA Technical Reports Server (NTRS), COMPUTER VISION, FUZZY SETS, IMAGE ANALYSIS, SCENE ANALYSIS,...
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To understand the benefits that surface modifications provide, and ultimately to devise better ones, it is necessary to study the physical, mechanical, and chemical changes they cause. This chapter surveys classical and leading-edge developments in surface structure and property characterization methodologies. The primary emphases are on the use of these techniques as they relate to surface modifications, thin films and coatings, and tribological engineering surfaces and on the implications...
Topics: NASA Technical Reports Server (NTRS), THIN FILMS, TRIBOLOGY, SURFACE PROPERTIES, CHEMICAL...
The work reported herein is an extension to the work accomplished under NASA Grant NAG1-2091 on the development of noise/source/path identification techniques for single engine propeller driven General Aviation aircraft. The previous work developed a Conditioned Response Analysis (CRA) technique to identify potential noise sources that contributed to the dominating tonal responses within the aircraft cabin. The objective of the present effort was to improve and verify the findings of the CRA...
Topics: NASA Technical Reports Server (NTRS), GENERAL AVIATION AIRCRAFT, AIRCRAFT COMPARTMENTS, NOISE...
The advent of powerful graphics workstations and computers has led to the advancement of scientific knowledge through three-dimensional (3-D) reconstruction and imaging of biological cells and tissues. The Biocomputation Center at NASA Ames Research Center pioneered the effort to produce an entirely computerized method for reconstruction of objects from serial sections studied in a transmission electron microscope (TEM). The software developed, ROSS (Reconstruction of Serial Sections), is now...
Topics: NASA Technical Reports Server (NTRS), IMAGING TECHNIQUES, THREE DIMENSIONAL MODELS, COMPUTER...
A component screening facility has been established at The NASA Glenn Research Center (GRC) to evaluate candidate materials for next generation, lithium-based, polymer electrolyte batteries for aerospace applications. Procedures have been implemented to provide standardized measurements of critical electrolyte properties. These include ionic conductivity, electronic resistivity, electrochemical stability window, cation transference number, salt diffusion coefficient and lithium plating...
Topics: NASA Technical Reports Server (NTRS), ELECTROLYTES, LITHIUM BATTERIES, POLYMERS, RECHARGING,...
The scientific objective of the Isothermal Dendritic Growth Experiment (IDGE) is to test fundamental assumptions about dendritic solidification of molten materials. "Dendrites"-- from the ancient Greek word for tree--are tiny branching structures that form inside molten metal alloys when they solidify during manufacturing. The size, shape, and orientation of the dendrites have a major effect on the strength, ductility (ability to be molded or shaped), and usefulness of an alloy....
Topics: NASA Technical Reports Server (NTRS), CRYSTAL GROWTH, DENDRITIC CRYSTALS, SOLIDIFICATION, ALLOYS,...
Photolysis of o-methylphenyl ketones generates bis-o-quinodimethane intermediates that can be trapped in situ by dienophiles through Diels-Alder cycloadditions. This well-known photochemical process is applied to a series of six new photoreactive monomers containing bis-(o-methylphenyl ketone) functionalities combined with diacrylate and triacrylate ester monomers for the development of acrylic ester copolymer blends. Irradiation of cyclohexanone solutions of the bis-(o-methylphenyl ketone)s...
Topics: NASA Technical Reports Server (NTRS), DIELS-ALDER REACTIONS, ACRYLATES, PHOTOCHEMICAL REACTIONS,...
Present-day Mars does not possess an active core dynamo and associated global magnetic field. However, the discovery of intensely magnetized crust in Mars Southern hemisphere implies that a Martian dynamo has existed in the past. Resolving the history of the Martian core dynamo is important for understanding the evolution of the planet's interior. Moreover, because the global magnetic field provided by an active dynamo can shield the atmosphere from erosion by the solar wind, it may have...
Topics: NASA Technical Reports Server (NTRS), PLANETARY MAGNETIC FIELDS, MARS (PLANET), MAGNETIC...
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NASA s Ultra-Efficient Engine Technology (UEET) program was formed in 1999 at Glenn Research Center to manage an important national propulsion program for the Space Agency. The UEET program s focus is on developing innovative technologies to enable intelligent, environmentally friendly, and clean-burning turbine engines capable of reducing harmful emissions while maintaining high performance and increasing reliability. Seven technology projects exist under the program, with each project working...
Topics: NASA Technical Reports Server (NTRS), POLYMER MATRIX COMPOSITES, HIGH TEMPERATURE, TURBINE ENGINES,...
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The Kodiak Star Mission was very challenging and offers significant lesson for future missions. A multinational fully integrated team had the opportunity to perform a truly first of a kind mission from a new launch complex with a unique manifest of experimental spacecraft. The integration goal of 10-months was met utilizing quick identification of the issues, and determining innovative ways to solve the problems
Topics: NASA Technical Reports Server (NTRS), EXPENDABLE STAGES (SPACECRAFT), SMALL SATELLITE TECHNOLOGY,...
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A conformable TPS over a rigid aeroshell has the potential to solve a number of challenges faced by traditional rigid TPS materials (such as tiled Phenolic Impregnated Carbon Ablator (PICA) system on MSL. The compliant (high strain to failure) nature of the conformable ablative materials will allow integration of the TPS with the underlying aeroshell structure much easier and enable monolithic-like configuration and larger segments (or parts) to be used. In May of 2013 the CA250 project...
Topics: NASA Technical Reports Server (NTRS), ABLATIVE MATERIALS, CARBON-PHENOLIC COMPOSITES, HEAT...
This paper presents a mathematically rigorous, subspace projection-based reduced order modeling (ROM) methodology and an integrated framework to automatically generate reduced order models for spacecraft thermal analysis. Two key steps in the reduced order modeling procedure are described: (1) the acquisition of a full-scale spacecraft model in the ordinary differential equation (ODE) and differential algebraic equation (DAE) form to resolve its dynamic thermal behavior; and (2) the ROM to...
Topics: NASA Technical Reports Server (NTRS), SPACECRAFT DESIGN, SPACECRAFT MODELS, THERMAL ANALYSIS,...
Thermoelectric materials based on the skutterudite crystal structure have demonstrated enhanced performance (ZT greater than 1), along with good thermal stability and favorable mechanical properties. Binary skutterudites, with single and multiple fillers, have been intensively studied in recent years. Compared to binary skutterudites, the ternary systems have received less attention, e.g. Ni4Sb8Sn4. Ternary skutterudites are isoelectronic variants of binary skutterudites; cation substitutions...
Topics: NASA Technical Reports Server (NTRS), THERMOELECTRIC MATERIALS, TERNARY SYSTEMS, ELECTRICAL...
Rate constants for the reaction of atomic chlorine with methane have been measured from 200-500K using the flash photolysis-resonance fluorescence technique. When the results from fourteen equally spaced experimental determinations are plotted in Arrhenius form a definite curvature is noted. The results are compared to previous work and are theoretically discussed.
Topics: NASA Technical Reports Server (NTRS), ATOMIC RECOMBINATION, CHEMICAL REACTIONS, CHLORINE, METHANE,...
The structure and direction of bow shock waves and the occurence of Pc 3, 4 micropulsations were investigated. An observational description is given of a quasi-parallel structure in a plasma parameter regime. The use of approximation to estimate the thickness of thin, nearly perpendicular bow shocks at supralaminar Mach numbers is discussed. The pattern of energies of backstreaming protons in the foreshock are predicted.
Topics: NASA Technical Reports Server (NTRS), BOW WAVES, EARTH MAGNETOSPHERE, GEOMAGNETIC MICROPULSATIONS,...
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The principles of electrohydrodynamic heat pip operation are first discussed. Evaporator conductance experiments are then described. A heat pipe was designed in which grooved and ungrooved evaporator surfaces could be interchanged to evaluate the necessity of capillary grooves. Optimum electrode spacing was also studied. Finally, heat convection in evaporating thin films is considered.
Topics: NASA Technical Reports Server (NTRS), ELECTROHYDRODYNAMICS, HEAT PIPES, CONVECTION, EVAPORATION,...
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by NASA Technical Reports Server (NTRS)
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A method for obtaining electronic chroma signals with a single scanning-type image device is described. A color multiplexed light signal is produced using an arrangement of dichroic filter stripes. In the particular system described, a two layer filter is used to color modulate external light which is then detected by an image pickup tube. The resulting time division multiplexed electronic signal from the pickup tube is converted by a decoder into a green color signal, and a single red-blue...
Topics: NASA Technical Reports Server (NTRS), COLOR TELEVISION, IMAGE TUBES, MULTIPLEXING, OPTICAL FILTERS,...
The effects of chronic centrifugation on body composition and growth of rats, mice, monkeys, and man are studied. The benefits of exercise and restraint during acceleration are investigated. Physiological regulation and energy balance are also discussed.
Topics: NASA Technical Reports Server (NTRS), BODY COMPOSITION (BIOLOGY), BODY MEASUREMENT (BIOLOGY),...
The preliminary designs, specifications, and programmatic data for the auxiliary payload power system (APPS) are presented. The APPS concept is an independent system to be carried in the Orbiter's cargo bay having the capability of housing and supporting space processing applications (SPA) experiment payloads and augmenting Spacelab power and heat rejection capabilities as required in the performance of these experiments.
Topics: NASA Technical Reports Server (NTRS), AUXILIARY POWER SOURCES, PAYLOADS, SPACE PROCESSING,...
The first and second variations are calculated for the irreducible form of Hamilton's Principle that involves the minimum number of dependent variables necessary to describe the kinetmatics and thermodynamics of inviscid, compressible, baroclinic flow in a specified gravitational field. The form of the second variation shows that, in the neighborhood of a stationary point that corresponds to physically stable flow, the action integral is a complex saddle surface in parameter space. There exists...
Topics: NASA Technical Reports Server (NTRS), BAROCLINITY, COMPRESSIBLE FLOW, INVISCID FLOW, FREE ENERGY,...
A general method for computing laminar and turbulent boundary layers for two-dimensional time-dependent flows is presented. The method uses an eddy-viscosity formulation to model the Reynolds shear-stress term and a very efficient numerical method to solve the governing equations. The model was applied to steady two-dimensional and three-dimensional flows and was shown to give good results. A discussion of the numerical method and the results obtained by the present method for both laminar and...
Topics: NASA Technical Reports Server (NTRS), LAMINAR BOUNDARY LAYER, TIME DEPENDENCE, TURBULENT BOUNDARY...
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Multiple arcs of rugged mountains and adjacent plains on the surface of Mars were examined. These features, located in the southern polar region were photographed by Mariner 9. Comparisons are made with characteristics of a lunar basin and mare; Mare imbrium in particular. The martian feature is interpreted to have originated in the same way as its lunar analog- by volcanic flooding of a large impact basin. Key data and methodology leading to this conclusion are cited.
Topics: NASA Technical Reports Server (NTRS), GEOLOGICAL SURVEYS, MARS SURFACE, POLAR CAPS, TERRAIN...
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A modular, multiple output power converter was developed in order to reduce costs of space hardware in future missions. The converter is of reduced size and weight, and utilizes advanced heat removal techniques, in the form of heat pipes which remove internally generated heat more effectively than conventional methods.
Topics: NASA Technical Reports Server (NTRS), ELECTRONIC MODULES, HEAT PIPES, VOLTAGE CONVERTERS (DC TO...
It is shown that the high flux of energetic plasma electrons and the reduced photoemission rate in the Jovian environment can result in the spacecraft developing a large negative potential. The effects of the electric fields produced by this charging phenomenon are discussed in terms of spacecraft integrity as well as charged particle and fields measurements. The primary area of concern is shown to be the interaction of the electric fields with the measuring devices on the spacecraft. The need...
Topics: NASA Technical Reports Server (NTRS), JUPITER PROBES, POTENTIAL, CHARGED PARTICLES, CHARGING,...
A feasibility study of modern airships has been completed. Three promising modern airship systems' concepts and their associated missions were studied; (1) a heavy-lift airship, employing a non-rigid hull and a significant amount of rotor lift, used for short-range transport and positioning of heavy military and civil payloads, (2) a VTOL (vertical take-off and landing), metalclad, partially buoyant airship used as a short-haul commercial transport; and (3) a class of fully-buoyant airships...
Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC CHARACTERISTICS, AIRCRAFT DESIGN, AIRSHIPS,...
An analysis was made of the errors in the determination of the position of an emergency transmitter in a satellite aided search and rescue system. The satellite was assumed to be at a height of 820 km in a near circular near polar orbit. Short data spans of four minutes or less were used. The error sources considered were measurement noise, transmitter frequency drift, ionospheric effects and error in the assumed height of the transmitter. The errors were calculated for several different...
Topics: NASA Technical Reports Server (NTRS), ERROR ANALYSIS, POSITION (LOCATION), RELAY SATELLITES, RESCUE...
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The thermal imaging technique was evaluated for its capabilities in the nondestructive evaluation of solar cell welds. The temperature and spatial resolution of state of the art instrumentation was sufficient for both qualitative and quantitative determination of the quality of solar cell welds. The addition of color digitized thermography enhanced the aspects of the thermographic display and allowed easily computerized testing procedures. For automated testing systems an accurate correlation...
Topics: NASA Technical Reports Server (NTRS), SOLAR CELLS, WELDING, HOLOGRAPHY, IMAGING TECHNIQUES,...
Zonal velocity profiles in the Venus atmosphere above the clouds were estimated from measured asymmetries of HCl and HF infrared absorption lines in high-resolution Fourier interferometer spectra of the planet. These asymmetries are caused by both pressure-induced shifts in the positions of the hydrogen-halide lines perturbed by CO2 and Doppler shifts due to atmospheric motions. Particularly in the case of the HCl 2-0 band, the effects of the two types of line shifts can be easily isolated,...
Topics: NASA Technical Reports Server (NTRS), ESTIMATING, INFRARED SPECTRA, VENUS ATMOSPHERE, WIND...
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The remote multiplexer/digitizer unit for the airborne integrated flight test data system was subjected to a flight test environment in order to study its dynamic response and that of its associated instrumentation circuitry during an actual flight test. The shielding schemes and instrumentation used are described and the data obtained are analyzed.
Topics: NASA Technical Reports Server (NTRS), ANALOG TO DIGITAL CONVERTERS, DYNAMIC RESPONSE, ELECTRONIC...
The laser beam manifold, a device for transforming a single, narrow, collimated beam of light into several beams of desired intensity ratios is described. The device consists of a single optical substrate with a metallic coating on both optical surfaces. By changing the entry point, the number of outgoing beams can be varied.
Topics: NASA Technical Reports Server (NTRS), BEAM SPLITTERS, LASERS, LENS DESIGN, ENERGY LEVELS, FILM...
The Dynamics Explorer A and B satellites designed to explore the interactive processes occuring between the magnetosphere and Earth's ionosphere, upper atmosphere, and plasmasphere are described. Effects of these interactions, satellite orbits, data collecting antennas, solar power systems, axes, configurations, and Earth based command, control and data display systems are mentioned.
Topics: NASA Technical Reports Server (NTRS), EXPLORER SATELLITES, MISSION PLANNING, PRELAUNCH TESTS, SOLAR...
A ternary-diagram approach is used to show on a single map as much detailed geochemical information concerning petrologic variations within the lunar crust as is possible. The classification map shows the global spatial distributions of end-member compositions, the transitional spatial relations between end-member compositions, and quantitative estimates of relative proportions of each end member at each pixel location within the orbital groundtracks. The use of elemental ratios in this...
Topics: NASA Technical Reports Server (NTRS), CHEMICAL ELEMENTS, DIAGRAMS, LUNAR CRUST, LUNAR GEOLOGY,...
This bibliography lists 1,133 reports, articles, and other documents introduced into the NASA scientific and technical information system between July 1, 1987 and December 31, 1987. Its purpose is to provide helpful information to the researcher, manager, and designer in technology development and mission design according to system, interactive analysis and design, structural and thermal analysis and design, structural concepts and control systems, electronics, advanced materials, assembly...
Topics: NASA Technical Reports Server (NTRS), CONTROL SYSTEMS DESIGN, INDEXES (DOCUMENTATION), MISSION...
The Middle Atmosphere Program (MAP) has provided a focus for considerable research on atmospherical radiative, chemical, and dynamical processes and the mutual coupling among these processes. In particular, major advances have occurred in the understanding of constituent transport as a result of near-global measurements obtained during MAP from several satellite based instruments (e.g., LIMS, SAMS, SAGE, and SSU among others). Using selected portions of these data, the development is reviewed...
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC CHEMISTRY, ATMOSPHERIC CIRCULATION, COUPLING,...
The purpose of the presentation is to show how we modify SGI Tempo cluster management software for large scale ICE systems (Pleiades).
Topics: NASA Technical Reports Server (NTRS), REVISIONS, COMPUTER SYSTEMS PROGRAMS, ARCHITECTURE...
The Infrared Interferometer Spectrometer (IRIS) instrument on board Voyager 1 caught the first glimpse of an unidentified particulate feature in Titan's stratosphere that spectrally peaks at 221 per centimeter. Until recently, this feature that we have termed 'the haystack,' has been seen persistently at high northern latitudes with the Composite Infrared Spectrometer (CIRS) instrument onboard Cassini, The strength of the haystack emission feature diminishes rapidly with season, becoming...
Topics: NASA Technical Reports Server (NTRS), LATITUDE, STRATOSPHERE, WINTER, INFRARED SPECTROMETERS,...
In the gridpoint statistical interpolation (GSI) data assimilation algorithm, only thermal infrared measurements determined to be uncontaminated by clouds are assimilated. Using this approach, typically only 19-29% of footprints are deemed to have no cloud affects through the measured spectra. This study will discuss the efforts underway at the Global Modeling and Assimilation Office (GMAO) at NASA Goddard Space Flight Center, in conjunction with the Joint Center for Satellite Data Assimilation...
Topics: NASA Technical Reports Server (NTRS), INFRARED RADIATION, INTERPOLATION, RADIATIVE TRANSFER, CLOUDS...
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Topics: NASA Technical Reports Server (NTRS), SPACE DEBRIS, AEROSPACE ENVIRONMENTS, LOW EARTH ORBITS,...
Direct computer simulations of electromagnetic scattering by discrete random media have become an active area of research. In this progress review, we summarize and analyze our main results obtained by means of numerically exact computer solutions of the macroscopic Maxwell equations. We consider finite scattering volumes with size parameters in the range, composed of varying numbers of randomly distributed particles with different refractive indices. The main objective of our analysis is to...
Topics: NASA Technical Reports Server (NTRS), BACKSCATTERING, COMPUTERIZED SIMULATION, ELECTROMAGNETIC...
In a recent publication, LeBlanc and McDermid proposed a hybrid calibration technique for Raman water vapor lidar involving a tungsten lamp and radiosondes. Measurements made with the lidar telescope viewing the calibration lamp were used to stabilize the lidar calibration determined by comparison with radiosonde. The technique provided a significantly more stable calibration constant than radiosondes used alone. The technique involves the use of a calibration lamp in a fixed position in front...
Topics: NASA Technical Reports Server (NTRS), CALIBRATING, OPTICAL RADAR, LUMINAIRES, RADIOSONDES, WATER...
The next generation large aperture UV/Optical space telescope will need a diameter substantially larger than even that of JWST in order to address some of the most compelling unanswered scientific quests. These quests include understanding the earliest phases of the Universe and detecting life on exo-planets by studying spectra of their atmospheres. Such 8-16 meter telescopes face severe challenges in terms of cost and complexity and are unlikely to be affordable unless a new paradigm is...
Topics: NASA Technical Reports Server (NTRS), SOLAR OPTICAL TELESCOPE, APERTURES, DEFORMABLE MIRRORS,...
Recently the issue on glacier retreats comes up and many factors should be relevant to the issue. The absorbing aerosols such as dust and black carbon (BC) are considered to be one of the factors. After they deposited onto the snow surface, it will reduce snow albedo (called snow darkening effect) and probably contribute to further melting of glacier. The Goddard Earth Observing System version 5 (GEOS-5) has developed at NASAlGSFC. However, the original snowpack model used in the land surface...
Topics: NASA Technical Reports Server (NTRS), AEROSOLS, CLIMATE, EARTH OBSERVING SYSTEM (EOS), IMAGING...
Accurate electron-hydrogen and electron-hydrogenic cross sections are required to interpret fusion experiments, laboratory plasma physics and properties of the solar and astrophysical plasmas. We have developed a method in which the short-range and long-range correlations can be included at the same time in the scattering equations. The phase shifts have rigorous lower bounds and the scattering lengths have rigorous upper bounds. The phase shifts in the resonance region can be used to calculate...
Topics: NASA Technical Reports Server (NTRS), ELASTIC SCATTERING, HYDROGEN, PLASMA PHYSICS, SPACE PLASMAS,...
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The Transiting Exoplanet Survey Satellite (TESS) will discover thousands of exoplanets in orbit around the brightest stars in the sky. In a two-year survey, TESS will monitor more than 500,000 stars for temporary drops in brightness caused by planetary transits. This first-ever spaceborne all-sky transit survey will identify planets ranging from Earth-sized to gas giants, around a wide range of stellar types and orbital distances. No ground-based survey can achieve this feat. A large fraction...
Topics: NASA Technical Reports Server (NTRS), EXTRASOLAR PLANETS, MAIN SEQUENCE STARS, PLANET DETECTION,...
The exobiology program investigates the planetary events which were responsible for, or, related to, the origin, evolution, and distribution of life in the universe. The areas involved include: chemical evolution, organic geochemistry, origin and evolution of life, planetary environments, life in the universe, planetary protection, and Mars data analysis.
Topics: NASA Technical Reports Server (NTRS), BIOLOGICAL EVOLUTION, CHEMICAL EVOLUTION, EXOBIOLOGY,...
Design, fabrication and test of the Block IV residential load module are reported. Design changes from the proposed module design through three iterations to the discontinuance of testing are outlined.
Topics: NASA Technical Reports Server (NTRS), RESIDENTIAL ENERGY, SOLAR CELLS, SOLAR HOUSES, DESIGN...
The time dependence of the emitted currents during arcing on solar cell arrays is being studied. The arcs are characterized using three parameters: the voltage change of the array during the arc (i.e., the charge lost), the peak current during the arc, and the time constant describing the arc current. This paper reports the dependence of these characteristics on two array parameters, the interconnect bias voltage and the array capacitance to ground. It was found that the voltage change of the...
Topics: NASA Technical Reports Server (NTRS), ARC DISCHARGES, CAPACITANCE, PLASMA INTERACTIONS, SOLAR...
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A centrifugal compressor is described which includes at least one pair of cylinders arranged in coaxial alignment and supported for angular displacement about a common axis of rotation normally disecting a common longitudinal axis of symmetry for the cylinders. The cylinders are characterized by ported closures located at the mutually remote ends thereof through which the cylinders are charged and discharged, and a pair of piston heads seated within the cylinders and supported for floating...
Topics: NASA Technical Reports Server (NTRS), AXES OF ROTATION, CENTRIFUGAL COMPRESSORS, PISTONS, ANGULAR...
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A framework for rigorously specifying the behavior of concurrent systems is proposed. It is based on the view of a concurrent system as a collection of interacting processes but no assumptions are made about the mechanisms for process synchronization and communication. A formal language is described that permits the expression of a broad range of logical and timing dependencies.
Topics: NASA Technical Reports Server (NTRS), COMPUTER PROGRAMMING, COMPUTERIZED SIMULATION, MATHEMATICAL...
The Anadarko Basin of western Oklahoma is a WNW-ESE elongated trough filled with of Paleozoic sediments. Most models call for tectonic activity to end in Pennsylvanian times. NASA Shuttle Imaging Radar revealed a distinctive and very straight lineament set extending virtually the entire length of the Anadarko Basin. The lineaments cut across the relatively flat-lying Permian units exposed at the surface. The character of these lineaments is seen most obviously as a tonal variation. Major...
Topics: NASA Technical Reports Server (NTRS), GEOCHRONOLOGY, GEOLOGICAL FAULTS, OKLAHOMA, STRUCTURAL...
A low-turbulence subsonic wind tunnel was used to study the influence of acoustic disturbances on the development of small sinusoidal oscillations (Tollmien-Schlichting waves) which constitute the initial phase of turbulent transition. It is found that acoustic waves propagating opposite to the flow generate vibrations of the model (plate) in the flow. Neither the plate vibrations nor the acoustic field itself have any appreciable influence on the stability of the laminar boundary layer. The...
Topics: NASA Technical Reports Server (NTRS), BOUNDARY LAYER STABILITY, LAMINAR BOUNDARY LAYER, SOUND...
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An investigation was made into the drag reduction capability of vortex tabs on delta wing vortex flaps. The vortex tab is an up-deflected leading edge portion of the vortex flap. Tab deflection augments vortex suction on the flap, thus improving its thrust, but the tab itself is drag producing. Whether a net improvement in the drag reduction can be obtained with vortex tabs, in comparison with plane vortex flaps of the same total area, was the objective of this investigation. Wind tunnel tests...
Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC DRAG, DELTA WINGS, LEADING EDGE FLAPS, VORTEX...
The amount of water in cloud droplet form ingested by a full-scale supersonic nose inlet with conical centerbody was measured in the NACA Lewis icing tunnel. Local and total water impingement rates on the cowl and centerbody surfaces were also obtained. All measurements were made with a dye-tracer technique. The range of operating and meteorological conditions studied was: angles of attack of 0 deg and 4.2 deg, volume-median droplet diameters from about 11 to 20 microns, and ratios of inlet to...
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The network, which is connected to a layer of 134 feed elements that transmit and receive microwaves, consists of a pair of circuit boards parallel to the feed element layer. One of the two boards has 87 dividers that each divide a signal to be transmitted into seven portions, and the other board has 134 combiners that each collect seven transmit signal portions and deliver the sum to one of the feed elements. A similar arrangement is used to handle received signals. The large number of...
Topics: NASA Technical Reports Server (NTRS), ANTENNA FEEDS, BEAMS (RADIATION), CIRCUIT BOARDS, MICROWAVES,...
The development of a biaxial extensometer capable of measuring axial, torsion, and diametral strains to near-microstrain resolution at elevated temperatures is discussed. An instrument with this capability was needed to provide experimental support to the development of viscoplastic constitutive models. The advantages gained when torsional loading is used to investigate inelastic material response at elevated temperatures are highlighted. The development of the biaxial extensometer was...
Topics: NASA Technical Reports Server (NTRS), EXTENSOMETERS, LOADS (FORCES), STRAIN MEASUREMENT, TIME...
The only two firmly identified galactic gamma-ray sources in the second COS B catalogue are the pulsars PSR 0531+21 (Crab) and PSR 0833-45 (Vela). In the region between 100 keV and 10 MeV the detailed shape of the emission is particularly important, since one expects a turn-off which is related to geometry of the source. A marginal evidence of such a turn-off just below 1 MeV has been reported for the Vela pulsar. In order to study sources with a well marked time signature in this energy band,...
Topics: NASA Technical Reports Server (NTRS), GAMMA RAY ASTRONOMY, GAMMA RAY OBSERVATORY, GAMMA RAY...
A new general-purpose optimization program for engineering design is described. ADS (Automated Design Synthesis - Version 1.10) is a FORTRAN program for solution of nonlinear constrained optimization problems. The program is segmented into three levels: strategy, optimizer, and one-dimensional search. At each level, several options are available so that a total of over 100 possible combinations can be created. Examples of available strategies are sequential unconstrained minimization, the...
Topics: NASA Technical Reports Server (NTRS), COMPUTER AIDED DESIGN, COMPUTER PROGRAMS, LAGRANGE...
Neutron-induced gamma ray production is an important source of background in Compton scatter gamma ray telescopes where organic scintillator material is used. Most important is deuteron formation when atmospheric albedo and locally produced neutrons are thermalized and subsequently absorbed in the hydrogenous material. The resulting 2.2 MeV gamma ray line radiation essentially represents a continuous isotropic source within the scintillator itself. Interestingly, using a scintillator material...
Topics: NASA Technical Reports Server (NTRS), BACKGROUND RADIATION, GAMMA RAY SPECTRA, NEUTRONS, PAIR...
Data on the fluctuations in depth of maximum development of cosmic ray air showers, corrected for the effects of mixed primary composition and shower development fluctuations, yield values of the inelastic proton-air cross section for laboratory energies in the range 10 to the 8th power to 10 to the 10th power GeV. From these values of proton-air cross section, corresponding values of the proton-proton total cross section are derived by means of Glauber theory and geometrical scaling. The...
Topics: NASA Technical Reports Server (NTRS), AIR, COSMIC RAY SHOWERS, ENERGY SPECTRA, FLUX DENSITY,...
Holographic interferometry and computer-assisted tomography (CAT) are used to determine the transonic flow field of a model rotor blade in hover. A pulsed ruby laser records 40 interferograms with a 61 cm-diam view field near the model rotor-blade tip operating at a tip Mach number of 0.90. After digitizing the interferograms and extracting fringe-order functions, the data are transferred to a CAT code. The CAT code then calculates pressure coefficients in several planes above the blade...
Topics: NASA Technical Reports Server (NTRS), BLADE TIPS, COMPUTER AIDED TOMOGRAPHY, DIGITAL TECHNIQUES,...
A multistep scenario which describes a plausible mass loss mechanism associated with red giant and related stars is outlined. The process involves triggering a condensation instability in an extended chromosphere, leading to the formation of cool, dense clouds which are conducive to the formation of molecules and dust grains. Once formed, the dust can be driven away from the star by radiation pressure. Consistency with various observed phenomena is discussed.
Topics: NASA Technical Reports Server (NTRS), CHROMOSPHERE, INTERSTELLAR MATTER, RED GIANT STARS, STELLAR...