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Aircraft stability and control data
Topic: NASA Technical Reports Server (NTRS)
Sequence of diffuse plasma resonances observed on Alouette 2 ionograms
Topic: NASA Technical Reports Server (NTRS)
NASA Network Resource and Training Site
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Laser beam scintillation and log-amplitude variance evaluation for wavelengths on digital computer
Topic: NASA Technical Reports Server (NTRS)
Analytical and experimental study of limitations in using small scale models for determining spacecraft thermal behavior
Topic: NASA Technical Reports Server (NTRS)
Intermediate resolution emission spectroscopy was used to study a group of 9 terrestrial silicates, 1 synthetic silicate, 6 meteorites and 2 lunar soils; comparisons were made with the intermediate resolution spectra of Comet Kohoutek in order to determine which materials best simulate the 10um astrophysical feature. Mixtures of silicates which would yield spectra matching the spectrum of the comet in the 10um region include: (1) A hydrous layer lattice silicate in combination with a high...
Topics: NASA Technical Reports Server (NTRS), ASTROPHYSICS, COMETS, EMISSION SPECTRA, INFRARED ASTRONOMY,...
Tabulations of maximum horizontal wind speed values are reported that were recorded at the Kennedy Space Center. Maximum wind speeds were recorded during the eight hurricanes which have affected the area--Cleo in August 1964 through Agnes in June 1972. Detailed tabulations and frequency distributions of daily maximum horizontal wind speeds recorded at NASA's 150 m ground tower facility at nine levels from December 1965 through March 1970 are also included.
Topics: NASA Technical Reports Server (NTRS), CAPE KENNEDY LAUNCH COMPLEX, HORIZON, WIND VELOCITY...
An aeromechanical analysis of the generation of an inlet vortex in a turbojet engine is presented. Methods for the prevention of vortex generation and methods of vortex damping are described.
Topics: NASA Technical Reports Server (NTRS), DAMPING, INLET FLOW, TURBOJET ENGINES, VORTEX ALLEVIATION,...
Within NASA's recent thrust for industrial collaboration, JPL (Jet Propulsion Laboratory) has recently established two technology cooperation agreements in the robotics area: one on virtual reality (VR) calibration with Deneb Robotics, Inc., and the other on redundant manipulator control with Robotics Research Corporation (RRC). These technology transfer cooperation tasks will enable both Deneb and RRC to commercialize enhanced versions of their products that will greatly benefit both space and...
Topics: NASA Technical Reports Server (NTRS), AEROSPACE TECHNOLOGY TRANSFER, CALIBRATING, COMPUTER SYSTEMS...
In today's world, three seemingly diverse fields - computer information technology, nanotechnology and biotechnology are joining forces to enlarge our scientific knowledge and solve complex technological problems. Our group is dedicated to conduct theoretical research exploring the challenges in this area. The major areas of research include: 1) Yeast Protein Interactions; 2) Protein Structures; and 3) Current Transport through Small Molecules.
Topics: NASA Technical Reports Server (NTRS), BIOTECHNOLOGY, NANOTECHNOLOGY, PROTEINS, WEBSITES, YEAST,...
NASA Network Resource and Training Site
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Through a Lewis CommTech Program project with the Cleveland Clinic Foundation, the NASA Lewis Research Center is playing a key role in the design and development of a permanently implantable, artificial heart pump assist device. Known as the Innovative Ventricular Assist System (IVAS), this device will take on the pumping role of the damaged left ventricle of the heart. The key part of the IVAS is a nonpulsatile (continuous flow) artificial heart pump with centrifugal impeller blades, driven by...
Topics: NASA Technical Reports Server (NTRS), BLOOD PUMPS, HEART, CLINICAL MEDICINE, BIOENGINEERING,...
This paper addresses the evolution of control strategies for a collective: a set of entities that collectively strives to maximize a global evaluation function that rates the performance of the full system. Directly addressing such problems by having a population of collectives and applying the evolutionary algorithm to that population is appealing, but the search space is prohibitively large in most cases. Instead, we focus on evolving control policies for each member of the collective. The...
Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, POPULATIONS, ROVING VEHICLES, COORDINATION,...
An important element in the design of NASA's Crew Exploration Vehicle (CEV) is the consideration given to crew safety during various ascent phase failure scenarios. To help ensure crew safety during this critical and dynamic flight phase, the CEV requirements specify that an abort capability must be continuously available from lift-off through orbit insertion. To address this requirement, various CEV ascent abort modes are analyzed using 3-DOF (Degree Of Freedom) and 6-DOF simulations. The...
Topics: NASA Technical Reports Server (NTRS), ASCENT, ABORTED MISSIONS, CREW EXPLORATION VEHICLE, LIFTOFF...
The last decade has seen a significant increase in the number and the capabilities of remote sensing satellites launched by the international community. A relatively new approach has been the launching of satellites into heterogeneous constellations. Constellations provide the scientists a capability to acquire science data, not only from specific instruments on a single satellite, but also from instruments on other satellites that fly in the same orbit. Initial results from the A-Train...
Topics: NASA Technical Reports Server (NTRS), SATELLITE CONSTELLATIONS, EARTH OBSERVATIONS (FROM SPACE),...
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Version 3 of the NPARC Navier-Stokes code includes support for large-grain (block level) parallelism using explicit message passing between a heterogeneous collection of computers. This capability has the potential for significant performance gains, depending upon the block data distribution. The parallel implementation uses a master/worker arrangement of processes. The master process assigns blocks to workers, controls worker actions, and provides remote file access for the workers. The...
Topics: NASA Technical Reports Server (NTRS), PARALLEL PROCESSING (COMPUTERS), PARALLEL COMPUTERS,...
NASA Network Resource and Training Site
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NASA Glenn Research Center has been working with industry, academia, and other government agencies in assessing commercial communications protocols for satellite and space-based applications. In addition, NASA Glenn has been developing and advocating new satellite-friendly modifications to existing communications protocol standards. This paper summarizes recent research into the applicability of various commercial standard protocols for use over satellite and space- based communications...
Topics: NASA Technical Reports Server (NTRS), SATELLITE COMMUNICATION, PROTOCOL (COMPUTERS), COMMUNICATION...
A key scientific objective of the original Boreal Ecosystem-Atmospheric Study (BOREAS) field campaign (1993-1996) was to obtain the baseline data required for modeling and predicting fluxes of energy, mass, and trace gases in the boreal forest biome. These data sets are necessary to determine the sensitivity of the boreal forest biome to potential climatic changes and potential biophysical feedbacks on climate. A considerable volume of remotely-sensed and supporting field data were acquired by...
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC COMPOSITION, BIOCHEMISTRY, BIOPHYSICS,...
Empirical correlation of high energy electrons into materials allows predictions of practical ranges (measure of electron penetration) for different elements and alloys.
Topics: NASA Technical Reports Server (NTRS), ALLOYS, ATOMIC WEIGHTS, CHEMICAL ELEMENTS, EXTRAPOLATION,...
Analytical models of three structures were used to test mass matrix-reduction schemes. Accuracy of four mode shapes and frequencies was tracked through successive mass matrix-reductions with diminishing numbers of indicator degrees of freedom. Results were consistently disappointing. Two new procedures were developed in attempt to improve accuracy.
Topics: NASA Technical Reports Server (NTRS), EIGENVALUES, METHODOLOGY, MODAL RESPONSE, RAYLEIGH-RITZ...
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by NASA Technical Reports Server (NTRS)
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An airlock for use in transferring waste objects from a positively pressurized enclosure aboard an operative space vehicle, to a waste receiver attached to the vehicle and maintained at the negative pressure of a celestial space environment. The airlock is characterized by a shell having an internal chamber and hermetically sealed within an opening formed in a bulkhead of the enclosure. The shell is provided with an insertion hatch adjacent to the enclosure, and an ejection hatch adjacent the...
Topics: NASA Technical Reports Server (NTRS), AIR LOCKS, PNEUMATIC EQUIPMENT, SPACECRAFT COMPONENTS,...
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A method for making a glass-to-metal seal is described. A domed metal enclosure having a machined seal ring is fitted to a glass post machined to a slight taper and to a desired surface finish. The metal part is then heated by induction in a vacuum. As the metal part heats and expands relative to the glass post, the metal seal ring, possessing a higher coefficient of expansion than the glass post, slides down the tapered post. Upon cooling, the seal ring crushes against the glass post forming...
Topics: NASA Technical Reports Server (NTRS), GLASS, MANUFACTURING, METALS, SEALS (STOPPERS),...
NASA Network Resource and Training Site
by NASA Technical Reports Server (NTRS)
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Launch window, flight performance, and recovery procedures for biosatellite
Topic: NASA Technical Reports Server (NTRS)
NASA Network Resource and Training Site
by NASA Technical Reports Server (NTRS)
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Fatigue resistant shear pin with hollow shaft and two plugs
Topic: NASA Technical Reports Server (NTRS)
NASA Network Resource and Training Site
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A model of the earth's crust is presented as a set of rigid crustal blocks in which the crust is consumed, compressed, or created only at the boundaries of the blocks. As such the trench boundary moves with respect to the colliding plates because of down-buckling at the corner of the descending plate. It is further shown that this mechanism requires plate consumption of the descending plate at a rate faster than the relative plate motion, which in turn causes infilling of the basin behind the...
Topics: NASA Technical Reports Server (NTRS), BUCKLING, EARTH CRUST, PLATES (STRUCTURAL MEMBERS),...
NASA Network Resource and Training Site
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A historical account of NASA's Apollo era engineers is presented. This book is based on interviews that were conducted with fifty-one 'typical' engineers.
Topics: NASA Technical Reports Server (NTRS), APOLLO PROJECT, ENGINEERING MANAGEMENT, HISTORIES, PERSONNEL,...
The results of research towards an ontology capture method referred to as IDEF5 are presented. Viewed simply as the study of what exists in a domain, ontology is an activity that can be understood to be at work across the full range of human inquiry prompted by the persistent effort to understand the world in which it has found itself - and which it has helped to shape. In the contest of information management, ontology is the task of extracting the structure of a given engineering,...
Topics: NASA Technical Reports Server (NTRS), DATA BASES, DOMAINS, EXPERT SYSTEMS, INFORMATION MANAGEMENT,...
The development of an analytical-numerical model to predict radiant emission or absorption is discussed. A voigt profile is assumed to predict the spectral qualities of a singlet atomic transition line for atomic species of interest to the OPAD program. The present state of this model is described in each progress report required under contract. Model and code development is guided by experimental data where available. When completed, the model will be used to provide estimates of specie...
Topics: NASA Technical Reports Server (NTRS), ABSORPTION SPECTRA, EMISSION SPECTRA, ENGINE MONITORING...
Most models of calcium aluminum-rich inclusions (CAI) have focused on early stages of formation by equilibrium crystallization of a homogeneous liquid. Less is known about the subsolidus cooling history of CAI. Chemical and isotopic heterogeneties on a scale of tens to hundreds of micrometers (e.g. MacPherson et al. (1989) and Podosek, et al. (1991)) suggest fairly rapid cooling with a minimum of subsolidus diffusion. However, transmission electron microscopy indicates that solid state...
Topics: NASA Technical Reports Server (NTRS), COOLING, INCLUSIONS, METEORITES, METEORITIC COMPOSITION,...
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Before a program can fail, a software fault must be executed, that execution must alter the data state, and the incorrect data state must propagate to a state that results directly in an incorrect output. This paper describes a tool called PISCES (developed by Reliable Software Technologies Corporation) for predicting the probability that faults in a particular program location will accomplish all three of these steps causing program failure. PISCES is a tool that is used during software...
Topics: NASA Technical Reports Server (NTRS), COMPUTER PROGRAMS, COMPUTER PROGRAM INTEGRITY, SOFTWARE...
Persistent structures in the turbulent boundary layer are located and analyzed. The data are taken from flight experiments on large commercial aircraft. An interval correlation technique is introduced which is able to locate the structures. The Morlet continuous wavelet is shown to not only locates persistent structures but has the added benefit that the pressure data are decomposed in time and frequency. To better understand how power is apportioned among these structures, a discrete Coiflet...
Topics: NASA Technical Reports Server (NTRS), TURBULENT BOUNDARY LAYER, COMMERCIAL AIRCRAFT, AIRFRAMES,...
The influence of compression and shear loads on the strength of composite laminates with z-pins is evaluated parametrically using a 2D Finite Element Code (FLASH) based on Cosserat couple stress theory. Meshes were generated for three unique combinations of z-pin diameter and density. A laminated plate theory analysis was performed on several layups to determine the bi-axial stresses in the zero degree plies. These stresses, in turn, were used to determine the magnitude of the relative load...
Topics: NASA Technical Reports Server (NTRS), COMPRESSIVE STRENGTH, LAMINATES, PLATES (STRUCTURAL MEMBERS),...
Growth of silicon dioxide on a silicon carbide crystal ensures proper orientation of photoresist masks on the crystals used for semiconductor devices. The crystal is heated in a water vapor-saturated gas to delineate p-n junctions that intersect the crystal surface.
Topic: NASA Technical Reports Server (NTRS)
Electron-hydrogen ionization considered from point of nonadiabatic theory
Topic: NASA Technical Reports Server (NTRS)
Magnetometers on a radial boom may be employed to determine the first N-1 multipole contributions to the spacecraft field and improve the total accuracy of a magnetic field experiment. The total error for systems of one to four magnetometers is investigated. The optimal magnetometer locations, for which the total error is a minimum, are found for given boom-length, instrument errors and magnetic field models characteristic for spacecraft with only a restricted or ineffective magnetic...
Topics: NASA Technical Reports Server (NTRS), MAGNETIC FIELDS, MAGNETOMETERS, SPACECRAFT ENVIRONMENTS,...
NASA Network Resource and Training Site
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An executive summary is presented of the escape/rescue and the hazards analyses for manned missions and operations in the 1980 time frame. The method of approach, basic data generated, and significant results are outlined, and highlights of the two analyses are given. Areas in which research or technical development efforts could improve mission safety, and specific suggestions for additional effort studies on safety analyses are listed.
Topics: NASA Technical Reports Server (NTRS), ESCAPE (ABANDONMENT), HAZARDS, LUNAR FLIGHT, RESCUE...
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Light from radiant energy source passes through filter, sample, and reference gas chambers to detector. Chamber with amount of gas to be measured is sealed. Filter may be gelatinous, interference, dispersive, or negative-gas, as required.
Topics: NASA Technical Reports Server (NTRS), ABSORPTION SPECTRA, COMPARATORS, GAS SPECTROSCOPY, INFRARED...
The acoustic impedance of sound absorbers in the presence of grazing flow is essential information when analyzing sound propagation within ducts. A unification of the theory of the nonlinear acoustic resistance of Helmholtz resonators including grazing flow is presented. The nonlinear resistance due to grazing flow is considered to be caused by an exciting pressure spectrum produced by the interaction of the grazing flow and the jets flowing from the resonator orifices. With this exciting...
Topics: NASA Technical Reports Server (NTRS), ACOUSTIC IMPEDANCE, ACOUSTIC MEASUREMENT, FLOW...
The longitudinal dynamic behavior of launch vehicles is largely determined by their huge liquid propellant masses which are spring supported by the elastic tank walls. Throughout much of the powered flight time, these masses constitute a high percentage of the entire vehicle mass and, therefore, may dominate the fundamental modes of the vehicle. In this report, a spherical container is considered. The analysis is based on a Galerkin approach, in the course of which a second-order differential...
Topics: NASA Technical Reports Server (NTRS), DYNAMIC CHARACTERISTICS, GREEN'S FUNCTIONS, PROPELLANT TANKS,...
The author has identified the following significant results. The crop types of a Great Plains study area were mapped from color infrared aerial photography. Each field was positively identified from field checks in the area. Enlarged (50x) density contour maps were constructed from three ERTS-1 images taken in the summer of 1973. The map interpreted from the aerial photography was compared to the density contour maps and the accuracy of the ERTS-1 density contour map interpretations were...
Topics: NASA Technical Reports Server (NTRS), COLOR PHOTOGRAPHY, CROP IDENTIFICATION, INFRARED PHOTOGRAPHY,...
There are no author-identified signficant results in this report.
Topics: NASA Technical Reports Server (NTRS), AGRICULTURE, CALIFORNIA, RESOURCES MANAGEMENT, RIVERS, SOIL...
Studies are presented on mesoscale weather monitoring, analysis, and dissemination of weather forecasts for the Wisconsin area.
Topics: NASA Technical Reports Server (NTRS), INFORMATION DISSEMINATION, MESOMETEOROLOGY, WEATHER...
Included in this plan are general objectives through Day 7, operational guidelines and restraints. Following the activation of all subsystems (through Day 3), special series of payload operations were performed to obtain data samples for the different combinations of exposure/gain settings. This took place from Day 4 through Day 7. The Orbit Adjust was employed to perform vernier corrections after the orbit had been defined. The orbit data was collected through Day 3, with the corrections being...
Topics: NASA Technical Reports Server (NTRS), LANDSAT 2, SPACE VEHICLE CHECKOUT PROGRAM, SPACECRAFT...
A test rig program was conducted with the objective of evaluating and minimizing the exhaust emissions, in particular NO sub x, of three advanced aircraft combustor concepts at a simulated, high altitude cruise condition. The three combustor designs, all members of the lean reaction, premixed family, are the Jet Induced Circulation (JIC) combustor, the Vortex Air Blast (VAB) combustor, and a catalytic combustor. They were rig tested in the form of reverse flow can combustors in the 0.127 m....
Topics: NASA Technical Reports Server (NTRS), COMBUSTION PRODUCTS, GAS TURBINE ENGINES, NITROGEN OXIDES,...
Transonic flight flutter tests of the XF3H-1 Demon Airplane were conducted utilizing a frequency response technique in which the oscillating rudder provides the means of system excitation. These tests were conducted as a result of a rudder flutter incident in the transonic speed range. The technique employed is presented including a brief theoretical development of basic concepts. Test data obtained during the flight are included and the method of interpretation of these data is indicated. This...
Topics: NASA Technical Reports Server (NTRS), CONTROL SURFACES, FLIGHT TESTS, FLUTTER, IMPEDANCE, TRANSONIC...
The author has identified the following significant results. The RMSE of point location achieved with the annotation system on S190A imagery was 100 m and 90 m in the x and y direction, respectively. Potential gains in sampling precision attributable to space derived imagery ranged from 4.9 to 43.3 percent depending on the image type, interpretation method, time of year, and sampling method applied. Seasonal variation was significant. S190A products obtained in September yielded higher gains...
Topics: NASA Technical Reports Server (NTRS), FORESTS, MULTISPECTRAL PHOTOGRAPHY, TIMBER INVENTORY, EREP,...
A series of measurements of near field pressures and turbulent velocity fluctuations were made in a low speed jet with a Reynolds number near 50,000 in order to investigate more quantitatively the character and behavior of the large scale structures and their interactions with each other. The near field measurements were modelled according to the vortex pairing hypothesis to deduce the distribution of pairings along the jet axis and the variances about the mean locations. The hodograph plane...
Topics: NASA Technical Reports Server (NTRS), FLOW DISTRIBUTION, PRESSURE DISTRIBUTION, SHEAR LAYERS,...
A piloted simulation study was conducted with the aim of advancing the development of longitudinal handling qualities criteria for large supersonic cruise aircraft. The areas of study investigated included high-speed cruise maneuvering, and stall-recovery control power. Comparisons were made with existing criteria and, for the cruise condition, a time response criterion was developed which correlated well with pilot ratings and comments. For low-speed stall recovery a new criterion was...
Topics: NASA Technical Reports Server (NTRS), AIRCRAFT CONTROL, FLIGHT SIMULATION, LONGITUDINAL CONTROL,...
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Multilayered mercury-cadmium telluride photoconductive detectors were developed which are capable of providing individual coverage of three separate spectral wavelength bands without the use of beam splitters. The multilayered "three-color" detector on a single dewar takes the place of three separate detector/filter/dewar units and enables simpler and more reliable mechanical and optical designs for multispectral scanners and radiometers. Wavelength channel design goals (in...
Topics: NASA Technical Reports Server (NTRS), INFRARED DETECTORS, LAMINATES, MERCURY TELLURIDES, MERCURY...
NASA Network Resource and Training Site
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State-of-the-art technologies applicable to silicon solar cell and solar cell module fabrication were assessed. The assessment consisted of a technical feasibility evaluation and a cost projection for high volume production of solar cell modules. Design equations based on minimum power loss were used as a tool in the evaluation of metallization technologies. A solar cell process sensitivity study using models, computer calculations, and experimental data was used to identify process step...
Topics: NASA Technical Reports Server (NTRS), COST ANALYSIS, CRYSTAL GROWTH, SOLAR ARRAYS, SOLAR CELLS,...
NASA Network Resource and Training Site
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The briefing reviewed the mission planning of the Voyager project. The near encounter trajectories of both Voyager spacecraft were examined. The Saturn system is discussed with particular emphasis on Saturn's moons.
Topics: NASA Technical Reports Server (NTRS), PROJECT PLANNING, SATURN PROJECT, SPACECRAFT TRAJECTORIES,...
This analysis was based on the technical and economic models in f-chart design procedures with inputs based on the characteristics of the parameters of present worth of system cost over a projected twenty year life: life cycle savings, year of positive savings, and year of payback for the optimized solar energy system at each of the analysis sites. The sensitivity of the economic evaluation to uncertainties in constituent system and economic variables was also investigated.
Topics: NASA Technical Reports Server (NTRS), ECONOMIC DEVELOPMENT, ENERGY POLICY, SOLAR COOLING, SOLAR...
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Orbital altitude, berthing and docking, Space Operation Center (SOC), SOC resupply and fuel transfer review, and flight support facility are reviewed.
Topics: NASA Technical Reports Server (NTRS), LARGE SPACE STRUCTURES, SPACE ERECTABLE STRUCTURES, SPACE...
An introduction to the system concepts: TELEDEMO and TELEDIMS is provided. TELEDEMO is derived primarily from computer graphics and, via incorporation of sophisticated image data compression, enables effective low cost teleconferencing at data rates as low as 1K bit/second using dial-up phone lines. Combining TELEDEMO's powerful capabilities for the development of presentation material with microprocessor-based Information Management Systems (IMS) yields a truly all electronic IMS called...
Topics: NASA Technical Reports Server (NTRS), COMPUTER GRAPHICS, INFORMATION MANAGEMENT, INFORMATION...
Development of a forecast of the total domestic telecommunications demand, identification of that portion of the telecommunications demand suitable for transmission by satellite systems, identification of that portion of the satellite market addressable by CPS systems, identification of that portion of the satellite market addressable by Ka-band CPS system, and postulation of a Ka-band CPS network on a nationwide and local level were achieved. The approach employed included the use of a variety...
Topics: NASA Technical Reports Server (NTRS), COMMUNICATION NETWORKS, COMMUNICATION SATELLITES, DATA...
NASA Network Resource and Training Site
by NASA Technical Reports Server (NTRS)
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A review of several modal testing techniques is made, along with brief discussions of their advantages and limitations. A new technique is presented which overcomes many of the previous limitations. Several simulated experiments are included to verify the validity and accuracy of the new method. Conclusions are drawn from the simulation studies and recommendations for further work are presented. The complete computer code configured for the simulation study is presented.
Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, DEGREES OF FREEDOM, MODAL RESPONSE, COMPUTERIZED...
A procedure for experimentally determining, in terms of the particle motions, the shapes of the low order acoustic modes in enclosures is described. The procedure is based on finding differentiable functions which approximate the shape functions of the low order acoustic modes when these modes are defined in terms of the acoustic pressure. The differentiable approximating functions are formed from polynomials which are fitted by a least squares procedure to experimentally determined values...
Topics: NASA Technical Reports Server (NTRS), ACOUSTIC PROPAGATION, ENCLOSURES, MODAL RESPONSE, PARTICLE...
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The first month of spin-scan ozone imaging (SOI) data (October 1981) was processed and compared with total ozone mapping spectrometer and ground based data. Short term variations in the ozone field have been revealed using animated sequences of SOI data. High correlations were observed between SOI ozone and upper tropospheric meteorological data. The relationship between ozone and temperature in the stratosphere was investigated by examining Nimbus 4 backscattered ultraviolet ozone and...
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC COMPOSITION, COMPUTER PROGRAMS, DATA PROCESSING,...
An Advanced Imaging Communication System (AICS) was proposed in the mid-1970s as an alternative to the Voyager data/communication system architecture. The AICS achieved virtually error free communication with little loss in the downlink data rate by concatenating a powerful Reed-Solomon block code with the Voyager convolutionally coded, Viterbi decoded downlink channel. The clean channel allowed AICS sophisticated adaptive data compression techniques. Both Voyager and the Galileo mission have...
Topics: NASA Technical Reports Server (NTRS), DATA TRANSMISSION, GALILEO PROJECT, IMAGE PROCESSING, LUNAR...
A comparison of methods for selecting optimum TM band combinations for visual interpretation of data are examined. Two statistical methods and visual interpretation by experienced photointerpreters are compared using photographic chips of 1:250,000 scale prints and the digital equivalent of the chips. A mosaic of TM data of the Great Salt Lake area of Utah was done. The filtering process was reviewed since the results were not satisfactory.
Topics: NASA Technical Reports Server (NTRS), DATA INTEGRATION, IMAGE PROCESSING, LANDSAT 4, LANDSAT 5,...
The goal is to develop a technique via a hairpin vortex model of the turbulent boundary layer, which would lead to the estimation of the aerodynamic input for use in trailing edge noise prediction theories. The work described represents an initial step in reaching this goal. The hairpin vortex is considered as the underlying structure of the wall turbulence and the turbulent boundary layer is viewed as an ensemble of typical hairpin vortices of different sizes. A synthesis technique is examined...
Topics: NASA Technical Reports Server (NTRS), NOISE PREDICTION, TRAILING EDGES, TURBULENCE MODELS,...
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by NASA Technical Reports Server (NTRS)
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The Pinhole/Occulter Facility is a powerful tool for studying the physics of the extended corona and origins of the solar wind. Spectroscopic data acquired by the P/OF coronal instruments can greatly expand empirical information about temperatures, densities, flow velocities, magnetic fields, and chemical abundances in the corona out to r or approx. 10 solar radii. Such information is needed to provide tight empirical constraints on critical physical processes involved in the transport and...
Topics: NASA Technical Reports Server (NTRS), ENERGY TRANSFER, PARTICLE ACCELERATION, PLASMA HEATING, SOLAR...
The RANDOM Computer Program is a FORTRAN program for generating random number sequences and testing linear congruential random number generators (LCGs). The linear congruential form of random number generator is discussed, and the selection of parameters of an LCG for a microcomputer described. This document describes the following: (1) The RANDOM Computer Program; (2) RANDOM.MOD, the computer code needed to implement an LCG in a FORTRAN program; and (3) The RANCYCLE and the ARITH Computer...
Topics: NASA Technical Reports Server (NTRS), COMPUTER PROGRAMMING, CONGRUENCES, LINEARITY, RANDOM NUMBERS,...
Multi-Anode Microchannel Array (MAMA) detector systems with formats of 256 x 1024 pixels and active areas of 6 x 26 square mm are now under evaluation at visible, ultraviolet and soft x-ray wavelengths. Very-large-format versions of the MAMA detectors with formats of 2048 x 2048 pixels and active areas of 52 x 52 square mm are under development for use in the NASA Goddard Space Flight Center's Space Telescope Imaging Spectrograph (STIS). Open-structure versions of these detectors with CsI...
Topics: NASA Technical Reports Server (NTRS), MICROCHANNEL PLATES, PHOTOMULTIPLIER TUBES, RADIATION...
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A rotary coupling for connecting a driven part to a source of rotary force is described. This device transmits rotary force in one direction only and disengages to permit the driven part to free wheel when the input member is stopped and precludes the backdriving of rotary force from output member to input member. The coupling includes an input member having a splined shaft, a coupling member connected to the splined shaft, and a coaxial output member. The coupling member and the output member...
Topics: NASA Technical Reports Server (NTRS), CLUTCHES, COUPLINGS, ROTATING CYLINDERS, SHAFTS (MACHINE...
A number of aircraft and spacecraft configurations are being considered for future development. These include high-speed turboprop aircraft, advanced vertical take-off and landing fighter aircraft, and aerospace planes for hypersonic intercontinental cruise or flight to orbit and return. Review of the acoustic environment expected for these vehicles indicates levels high enough that acoustic fatigue must be considered. Unfortunately, the sonic fatique design technology used for current aircraft...
Topics: NASA Technical Reports Server (NTRS), ACOUSTIC FATIGUE, AIRCRAFT CONFIGURATIONS, LOADS (FORCES),...
Topics: NASA Technical Reports Server (NTRS), BAGS, FOAMS, LUNAR ROCKS, LUNAR SOIL, NETS, PAYLOADS, DEEP...
In normal spiral galaxies the arms are the main sites for star formation. This is the cause of their optical contrast compared with the rest of the disc. The spiral structure can be observed as a higher concentration of H2 regions, neutral gas (both atomic and molecular via CO), dust and stars than in the interarm disc. It seens generally accepted that, at least in grand design spirals, there are density waves in the discs. However, several questions are not clear yet and still under...
Topics: NASA Technical Reports Server (NTRS), DENSITY WAVE MODEL, GALACTIC STRUCTURE, SPIRAL GALAXIES, STAR...
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The distribution functions of photons in squeezed and correlated light for one-mode and multimode cases are obtained based on the method of integrals of motion. Correlation coefficient and squeezing parameter are calculated. The possibility to generate squeezed light using nonstationary Casimir effect is discussed. Quantum parametric Josephson junction is proposed as quantum vacuum generator of electrical vibrations.
Topics: NASA Technical Reports Server (NTRS), DISTRIBUTION FUNCTIONS, HARMONIC OSCILLATORS, INTEGRALS,...
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by NASA Technical Reports Server (NTRS)
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Viewgraphs on high rate science data handling are presented. Topics covered include: science needs versus technology; technology assessment; conceptual architecture; and direct downlink concept.
Topics: NASA Technical Reports Server (NTRS), DATA SYSTEMS, DOWNLINKING, SPACE STATION FREEDOM, TECHNOLOGY...
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The algebraic approach to quantum mechanics is briefly reviewed. The role of oscillator realizations is discussed. Applications to vibrations of complex molecules are presented.
Topics: NASA Technical Reports Server (NTRS), ALGEBRA, HAMILTONIAN FUNCTIONS, HARMONIC OSCILLATORS, QUANTUM...
Topic: NASA Technical Reports Server (NTRS)
Topic: NASA Technical Reports Server (NTRS)
Topic: NASA Technical Reports Server (NTRS)
Inserting a splitter plate in the subsonic diffuser caused a pressure-recovery loss of about 1 percent for an inlet with a long nearly constant-area throat section. The loss was due to the increased surface area. Another inlet, which had a comparatively rapid area increase immediately after the throat, experienced pressure-recovery losses of 5 and 6 percent at Mach numbers of 1.8 and 2.0, respectively, and about 1 percent at Mach 1.5.
Topic: NASA Technical Reports Server (NTRS)
Topic: NASA Technical Reports Server (NTRS)
Topic: NASA Technical Reports Server (NTRS)
Topic: NASA Technical Reports Server (NTRS)
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Winner-take-all (WTA) neural networks using pulse-firing processing elements are introduced. In the pulse-firing WTA (PWTA) networks described, input and activation signal shunting is controlled by one shared lateral inhibition signal. This organization yields an O(n) area complexity that is convenient for integrated circuit implementation. Appropriately specified network parameters allow for the accurate continuous evaluation of inputs using a signal representation compatible with established...
Topics: NASA Technical Reports Server (NTRS), NEURAL NETS, VERY LARGE SCALE INTEGRATION, CMOS, PULSES,...
The first attempts to explain the nature of dwarf novae were based on the assumption of single-star phenomena, in which emission lines were assumed to be caused by circumstellar gas shells. The outburst behavior was tentatively ascribed to the kind of (also not understood) mechanism leading to nova outbursts. The realization that some, and possibly all, dwarf novae and nova-like stars (and novae) are binaries eventually led to models which bore more and more similarities to the modern...
Topics: NASA Technical Reports Server (NTRS), ACCRETION DISKS, CATACLYSMIC VARIABLES, DWARF NOVAE, MASS...
Current system simulations are mature, difficult to modify, and poorly documented. Probabilistic life prediction techniques for space applications are in their early application stage. Many parts of the full system, variable fidelity simulation, have been demonstrated individually or technology is available from aeronautical applications. A 20% reduction in time to design with improvements in performance and risk reduction is anticipated. GRC software development will proceed with similar...
Topics: NASA Technical Reports Server (NTRS), PREDICTION ANALYSIS TECHNIQUES, COMPUTERIZED SIMULATION,...
Second quarter progress report for year 3 on contract NASW-99002 "What is the Relationship between heavy ion outflow and high latitude energetic particle precipitation". In this Project we are studying the relationship between the fluxes, mean energies, and field-aligned flow speeds of escaping suprathermal H+ and 0+ measured by the TEAMS instrument on FAST and the energy flux of precipitating electrons obtained from the LBHL images taken by the UVI camera on POLAR. In this portion of...
Topics: NASA Technical Reports Server (NTRS), ELECTRON PRECIPITATION, HYDROGEN IONS, OXYGEN IONS, ENERGETIC...
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Models of planet formation and of the orbital stability of planetary systems are described and used to discuss possible characteristics of undiscovered planetary systems. Modern theories of star and planet formation, which are based upon observations of the Solar System and of young stars and their environments, predict that rocky planets should form in orbit about most single stars. It is uncertain whether or not gas giant planet formation is common, because most protoplanetary disks may...
Topics: NASA Technical Reports Server (NTRS), GAS GIANT PLANETS, PLANETARY EVOLUTION, PLANETARY SYSTEMS,...
This presentation is designed as a limited-scope "tutorial" and is aimed primarily at the CFDer who has not been exposed to stability and control problems. Examples of some classic S&C problems are used for illustration. S&C is a fundamental technology for enabling flight, but significant problems with the prediction of S&C characteristics persists, especially where separated flow is involved. Even after 100 years of flight, experimental methods still have significant...
Topics: NASA Technical Reports Server (NTRS), COMPUTATIONAL FLUID DYNAMICS, STABILITY, ACTIVE CONTROL,...
The Numerical Propulsion System Simulation (NPSS), an advanced engineering simulation environment used to design and analyze aircraft engines, has been enhanced by integrating control development tools into it. One of these tools is a generic controller interface that allows NPSS to communicate with control development software environments such as MATLAB and EASY5. The other tool is a linear model generator (LMG) that gives NPSS the ability to generate linear, time-invariant state-space...
Topics: NASA Technical Reports Server (NTRS), PROPULSION SYSTEM CONFIGURATIONS, PROGRAMMING ENVIRONMENTS,...
The Lunar L1 and L2 libration points have been proposed as gateways granting inexpensive access to interplanetary space. To date, only individual solutions to the transfer between three-body systems have been found. The methodology to solve the problem for arbitrary three-body systems and entire families of orbits is currently being studied. This paper presents an initial approach to solve the general problem for single and multiple impulse transfers. Two different methods of representing and...
Topics: NASA Technical Reports Server (NTRS), MANIFOLDS (MATHEMATICS), LIBRATION, IMPULSES, LOW COST,...
Linear negative gravity anomalies in Acidalia Planitia along the eastern edge of Tempe Terra and along the northern edge of Arabia Terra have been noted in Mars Global Surveyor gravity fields. Once proposed to represent buried fluvial channels, it is now believed that these gravity troughs mainly arise from partial compensation of the hemispheric dichotomy topographic scarp. A recent inversion for crustal structure finds that mantle compensation of the scarp is offset from the present-day...
Topics: NASA Technical Reports Server (NTRS), TOPOGRAPHY, DICHOTOMIES, BOUNDARIES, MARS SURFACE, TROUGHS,...
A procedural code (C++) simulation was developed to investigate potentials for mixture ratio control of pressure-fed spacecraft rocket propulsion systems by measuring propellant flows, tank liquid quantities, or both, and using feedback from these measurements to adjust propellant tank pressures to set the correct operating mixture ratio for minimum propellant residuals. The pressurization system eliminated mechanical regulators in favor of a computer-controlled, servo- driven throttling valve....
Topics: NASA Technical Reports Server (NTRS), C++ (PROGRAMMING LANGUAGE), CONTROLLERS, FUEL TANK...
The method and apparatus for measuring the number of layers of a web material of known thickness wound on a storage or take-up reel is presented. The method and apparatus are based on the principle that, at a relatively large radius, the loci of layers of a thin web wound on the reel approximate a family of concentric circles having radii respectively successively increasing by a length equal to the web thickness. Tachometer pulses are generated in response to linear movement of the web and...
Topics: NASA Technical Reports Server (NTRS), MEASURING INSTRUMENTS, REELS, WEBS (SHEETS), DIGITAL...
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Theoretical and experimental research on structural-acoustic interaction is reviewed. The emphasis is upon the radiation from and acoustic loading of baffled rectangular plates and membranes. The topics discussed include a criterion for strong radiation loading, the mass law for a finite panel, numerical calculation of the radiation impedance of a finite panel in the presence of a parallel mean flow, and experimental determination of the effect of vibration amplitude and Mach number upon panel...
Topics: NASA Technical Reports Server (NTRS), BAFFLES, PANELS, SOUND PROPAGATION, ACOUSTIC IMPEDANCE, MASS,...
NASA Network Resource and Training Site
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A CW ultrasonic device is described for measuring frequency shifts of the peak of a mechanical resonance in a body. One application of the device is measuring the strain in a bolt, and other applications such as measuring the thickness of a body, measuring the depth of a flaw in a body, measuring the elongation of a body, and measuring changes in velocity of sound in a body. The body is connected, by means of a CW transducer, to electrical circuit means including a narrow band RF amplifier to...
Topics: NASA Technical Reports Server (NTRS), CONTINUOUS RADIATION, RESONANT FREQUENCIES, STRAIN GAGES,...
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by NASA Technical Reports Server (NTRS)
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A meteorological radar calibration technique is developed. It is found that the integrated, range corrected, received power saturates under intense rain conditions in a manner analogous to that encountered for the radiometric path temperature. Furthermore, it is found that this saturation condition establishes a bound which may be used to determine an absolution radar calibration for the case of radars operating at attenuating wavelengths. In the case of less intense rainfall or for radars at...
Topics: NASA Technical Reports Server (NTRS), CALIBRATING, METEOROLOGICAL RADAR, RAIN, RADAR MEASUREMENT,...
A fixed, linear, ground-based primary reflector is disclosed which has an extended curved sawtooth-contoured surface covered with a metalized polymeric reflecting material. The device reflects solar energy to a movably supported collector that is kept at the concentrated line focus of the reflector primary. The primary reflector may be constructed by a process utilizing well-known freeway paving machinery.
Topics: NASA Technical Reports Server (NTRS), ENERGY POLICY, SOLAR ENERGY, SOLAR REFLECTORS, ENERGY...
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Topics: NASA Technical Reports Server (NTRS), DEACTIVATION, LANDSAT 1, MALFUNCTIONS, LONGITUDINAL CONTROL,...
NASA Network Resource and Training Site
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Power plant studies have shown the attractiveness of MHD topped steam power plants for baseload utility applications. To realize these advantages, a three-phase development program was initiated. In the first phase, the engineering data and experience were developed for the design and construction of a pilot plant, the Engineering Test Facility (ETF). Results of the ETF studies are reviewed. These three parallel independent studies were conducted by industrial teams led by the AVCO Everett...
Topics: NASA Technical Reports Server (NTRS), FEASIBILITY ANALYSIS, POWER PLANTS, STRUCTURAL DESIGN...
NASA Network Resource and Training Site
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Viewpoints are presented on large structure control evolving from the solar sail study conducted at JPL. The objective is to make optimum use of insights gained in the study in order to assess required large structure control developments.
Topics: NASA Technical Reports Server (NTRS), LARGE SPACE STRUCTURES, SATELLITE CONTROL, DATA CORRELATION,...
Interplanetary acceleration processes are shown as the most plausible explanation for the observed corotating energetic particle events. The relation between the energetic particle events and the properties of the high speed solar wind streams observed at 1 AU were investigated along with the form of the energy spectrum of the corotating energetic particle streams and its variation with respect to CIR boundaries and with radial distance. It is shown that: (1) at 1 AU a correlation exists...
Topics: NASA Technical Reports Server (NTRS), ENERGETIC PARTICLES, INTERPLANETARY MEDIUM, PLASMA...
Light microscopy has greatly reduced analytical flow time and added new dimensions to laboratory capability. Aerospace analytical laboratories are often confronted with problems involving contamination, wear, or material inhomogeneity. The detection of potential problems and the solution of those that develop necessitate the most sensitive and selective applications of sophisticated analytical techniques and instrumentation. This inevitably involves light microscopy. The microscope can...
Topics: NASA Technical Reports Server (NTRS), MICROSCOPY, SPACE LABORATORIES, SPACECRAFT ENVIRONMENTS,...
A computerized simulation analysis for a number of scatterometer antenna configuration and polarization modes including the Seasat scatterometer (SASS) is presented. The results of the simulations were expressed in terms of performance statistics. These statistics relate to the wind direction alias removal capability and to the rms sensing errors for friction velocity and wind direction X. The statistics are analyzed, and optimum scatterometer configurations are recommended. The accuracy of the...
Topics: NASA Technical Reports Server (NTRS), MICROWAVE SCATTERING, OCEAN SURFACE, SCATTEROMETERS, ANTENNA...
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by NASA Technical Reports Server (NTRS)
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The relationship between multivariable zeros and inverse systems was explored. A definition of zero module is given in such a way that it is basis independent. The existence of essential right and left inverses were established. The way in which the abstract zero module captured previous definitions of multivariable zeros is explained and examples are presented.
Topics: NASA Technical Reports Server (NTRS), FEEDBACK CONTROL, MATHEMATICAL MODELS, DYNAMIC RESPONSE,...
An examination of a multiplicity of interconnected parameters ranging from specific technology details to total system economic costs for satellite communication systems at the 18/30 GHz transmission bands are presented. It was determined that K sub A band systems can incur a small communications outage during very heavy rainfall periods and that reducing the outage to zero would lead to prohibitive system costs. On the other hand, the economics of scale, ie, one spacecraft accommodating 2.5...
Topics: NASA Technical Reports Server (NTRS), COMMUNICATION NETWORKS, COMMUNICATION SATELLITES, DATA...
The activities feasibility of high temperature underground thermal storage of energy was investigated. Results indicate that salt cavern storage of hot oil is both technically and economically feasible as a method of storing huge quantities of heat at relatively low cost. One particular system identified utilizes a gravel filled cavern leached within a salt dome. Thermal losses are shown to be less than one percent of cyclically transferred heat. A system like this having a 40 MW sub t transfer...
Topics: NASA Technical Reports Server (NTRS), HEAT STORAGE, SOLAR ENERGY, UNDERGROUND STORAGE, COST...