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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Pneumatic impact wrench removes the nuts from freely turning bolts when the heads cannot be reached or the shafts anchored. It uses a fixed screwdriver blade that fits a slot cut into the threaded end of the bolt shaft.
Steady state and dynamic properties of journal bearings in laminar and superlaminar flow regimes
Electron decay rate and absorption cross sections for electron holes and recombination in gamma irradiated n-type silicon
Effects of shroud geometry on performance of collapsible plug nozzle at Mach numbers from 0 to 2.0
Operational performance of squeeze-film bearing with incorporated piezoelectric driver gyro
Device for measuring two orthogonal components of force with gallium flotation of measuring target for use in vacuum environments
Influence of small reference electrode in Langmuir probe measurement of plasma density and temperature
Body weakening due to symmetrically expanding crack, discussing internal pressure, elastic equilibrium and stress-strain state
New process produces controlled purity, very high strength, single crystal fibers of materials with melting points to 4000 C. Process has been used to make single crystal fibers of highly refractory ceramics such as aluminum oxide, titanium carbide and yttrium oxide.
An experimental investigation was made of the static and dynamic stability characteristics of a one-fourth scale model of a tilt-propeller free-wing V/STOL aircraft. The effects of wing pivot location, wing chord, trailing-edge angle, propeller tilt angle, and thrust were studied, and a limited evaluation was made of high-lift devices. A dynamically similar wing was used to measure frequency and damping ratio from transient response data in the linear aerodynamic regime and the results were compared to quasi-steady and unsteady aerodynamic theory. It was found that at high trim angles of attack, in the nonlinear aerodynamic regime, stall flutter oscillations occurred with typical amplitudes ranging from 15 to 20 deg. Wing control tab deflection was effective in initiating and terminating stall flutter but variations in configuration or operating conditions did not greatly influence the occurrence of characteristics of the oscillations.
Results of plasmapause measurements made onboard S cubed A (explorer 45) satellite are presented. Data cover model calculations made to explain the observed probe potential behavior, comparison of satellite data with VLF data to establish that certain effects seen are interpretable as the plasmapause, and plasmapause behavior during the December 17, 1971 magnetic storm.
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Unit includes rugged waterproof cables and equipment containers, low power, sturdy antenna construction, and easy equipment setup and serviceability. Accuracy and reliability of entire measurement system were not sacrificed.
The operational, economic, environmental, social and engineering feasibility of utilizing deactivated maritime vessels as a waterfront quiet short takeoff and landing facility to be located near the central business district of San Francisco was investigated. Criteria were developed to evaluate each site, and minimum standards were established for each criterion. Predicted conditions at the two sites were compared to the requirements for each of the 11 criteria as a means of evaluating site performance. Criteria include land use, community structure, economic impact, access, visual character, noise, air pollution, natural environment, weather, air traffic, and terminal design.
Liquid zones of water, soap solution and soap foam were deployed between two aligned circular disks which were free to rotate about the zone axis in the microgravity environment of Skylab IV. Such a configuration is of interest in the containerless handling of melts for possible future space processing crystal growth experiments. Three basic types of zone surface deformation and instability were observed for these rotational conditions; axisymmetric shape changes under single disk rotation, nonaxisymmetric, whirling, C-modes for long zones with equal rotation of both disks, and capillary wave phenomena for short zones with equal rotation of both disks. The sources of these instabilities and the conditions promoting them are analyzed in detail from video tape recordings of the Skylab experiments.
Data collected by SEASAT would be useful in developing predictive physical models for the drift and deformation of sea ice, for estimating the heat budget of the polar seas, for the optimum routing of shipping through pack ice areas, for the design of both offshore structures and shipping capable of surviving in heavy pack ice, and for the tracking of large icebergs and ice islands. The instrument package for SEASAT-A is particularly useful for studying sea ice in that the Coherent Imaging Radar (CIR), the Scanning Multifrequency Microwave Radiometer (SMMR) and the Compressed Pulse Radar Altimeter (CPRA) are not limited by the presence of clouds.
Thermal analysis (BETA) computer program adaptations were prepared to analyze phase change histories in crystal specimens. The first program (BETA-CYL) treats right circular cylinder configurations and the second, more general, program (BETA-BOR) treats a generalized body-of-revolution configuration. A series of computer runs were made for silicon material to determine boundary conditions which produce flat solidification interfaces while, at the same time, minimizing peak temperatures in the molten zone. Flat solidification interfaces are a goal believed by some investigators to be required to produce high quality semiconductor materials. The thermal effects of convection in a molten zone were examined and found to be negligible in comparison to the conduction heat transfer of the melt.
Surface tension driven flow in a cylindrical melt suspended between two rods was investigated by numerical solution of the steady state differential equations for heat and momentum transfer. Radiation heating and electron beam heating were considered approximately. For small values of the driving force, one rotating ring was formed in the top half of the zone, and its mirror image in the bottom half. At larger driving forces, secondary cells form which probably would undergo oscillatory motion. The influence of Prandtl number, zone movement, and buoyancy on the convection was also studied. The primary resistance to mass transfer in the laminar regime was in the center of the zone rather than at the solid-liquid interfaces.