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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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At least 1,351 records · Page 75
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

An investigation of wave-particle interactions and particle dynamics using electron beams injected from sounding rockets

Electrons with energy up to 40 kV have been injected into semi-trapped orbits from sounding rockets at Wallops Island, Virginia, and at Fort Churchill, Manitoba, Canada. By directing the rocket trajectory to have a horizontal component which in direction and speed matched the bounce displacement of the injected electrons, it was possible to detect conjugate echoes at Wallops and possibly at Churchill, and to study the distribution of the echoes in space, time and energy. By combining observations of many echoes, a composite picture can be obtained of the beam patterns. Atmospheric scattering at the conjugate point of Wallops Island has been extensively studied, and the process produces a scale width of 5-10 m, but with an echo intensity which is only 10% of theoretical estimates.

Winckler, J. R.↗
NASA NTRS1974

Space processing economics

Two types of space processing operations may be considered economically justified; they are manufacturing operations that make profits and experiment operations that provide needed applied research results at lower costs than those of alternative methods. Some examples from the Skylab experiments suggest that applied research should become cost effective soon after the space shuttle and Spacelab become operational. In space manufacturing, the total cost of space operations required to process materials must be repaid by the value added to the materials by the processing. Accurate estimates of profitability are not yet possible because shuttle operational costs are not firmly established and the markets for future products are difficult to estimate. However, approximate calculations show that semiconductor products and biological preparations may be processed on a scale consistent with market requirements and at costs that are at least compatible with profitability using the Shuttle/Spacelab system.

Bredt, J. H.↗
NASA NTRS1975

Exploration for fossil and nuclear fuels from orbital altitudes

A review of satellite-based photographic (optical and infrared) and microwave exploration and large-area mapping of the earth's surface in the ERTS program. Synoptic cloud-free coverage of large areas has been achieved with planimetric vertical views of the earth's surface useful in compiling close-to-orthographic mosaics. Radar penetration of cloud cover and infrared penetration of forest cover have been successful to some extent. Geological applications include map editing (with corrections in scale and computer processing of images), landforms analysis, structural geology studies, lithological identification, and exploration for minerals and fuels. Limitations of the method are noted.

Short, N. M.↗
NASA NTRS1977

A preliminary training guide for utilizing high-altitude, color-infrared photography in compiling soil maps

Instruction for acquiring and analytically processing small-scale color-infrared photography to perform a soil resources inventory over forests of the southern U.S. is provided. Planning the project; acquiring aerial photography, materials, equipment and supplemental data; and preparing the photography for analysis are discussed. The procedures for preparing ancillary and primary component overlays are discussed. The use of correlation charts and dichotomous keys for mountain landforms, water regime, and vegetation is explained.

Weaver, J. E.↗
NASA NTRS1976

High purity silica reflective heat shield development

A hyperpure vitreous silica material is being developed for use as a reflective and ablative heat shield for planetary entry. Various purity grades and forms of raw materials were evaluated along with various processing methods. Slip casting of high purity grain was selected as the best processing method, resulting in a highly reflective material in the wavelength bands of interest (the visible and ultraviolet regions). The selected material was characterized with respect to optical, mechanical and physical properties using a limited number of specimens. The process has been scaled up to produce a one-half scale heat shield (18 in. dia.) (45.72 cm) for a Jupiter entry vehicle. This work is now being extended to improve the structural safety factor of the heat shield by making hyperpure silica material tougher through the addition of silica fibers.

Nachtscheim, P. R.↗
NASA NTRS1977

Carotenoid diagenesis in a marine sediment

The major carotenoids at three levels (3, 40, and 175 m below the sediment-water interface) in a core from a marine sediment (Cariaco Trench, off Venezuela) have been examined. Mass and electronic spectral data have provided evidence for the onset of a progressive reduction of carotenoids in the geological column. The time scale of the process appears to depend on the particular carotenoid. Reduction of up to two double bonds is observed for the diol, zeaxanthin, in the oldest sediment (about 340,000 years old) but no reduction is observed in the younger samples (about 5000 and 56,000 years old). The diketone, canthaxanthin, shows evidence of reduction of up to two double bonds in the 56,000-yr sample and up to five double bonds in the oldest sample. No reduction of beta-carotene was observed in any of the samples.

Watts, C. D.↗
NASA NTRS1978

Solar silicon via the Dow Corning process

Carbon, as a reductant for quartz, must be made available so as to have suitable reactivity in conjunction with high purity, especially with respect to boron and phosphorus. A detailed experimental plan was developed to do this. Different sources of carbon were selected to be subjected to various purification methods and reactivity-enhancement processes. A developmental scale arc furnace was installed to perform quartz-carbon reactivity testing.

Hunt, L. P.↗
NASA NTRS1979

Manufacturing methods of a composite cell case for a Ni-Cd battery

Basic manufacturing method refinements for using graphite epoxy material for a nickel cadmium battery cell case were performed to demonstrate production feasibility. The various facets of production scale-up, i.e., process and tooling development, together with material and process control, were integrated into a comprehensive manufacturing process that assures production reproducibility and product uniformity. Test results substantiate that a battery cell case produced from graphite epoxy pre-impregnated material, utilizing the internal pressure bag fabrication method, is feasible.

Bauer, J. L.↗
NASA NTRS1979

Manufacturing methods of a composite cell case for a Ni-Cd battery

Graphite epoxy material for a nickel cadmium battery cell case has been evaluated and determined to perform in the simulated environment of the battery. The basic manufacturing method requires refinement to demonstrate production feasibility. The various facets of production scale-up, i.e., process and tooling development together with material and process control, have been integrated into a comprehensive manufacturing process that assures production reproducibility and product uniformity. Test results substantiate that a battery cell case produced from graphite epoxy pre-impregnated material utilizing internal pressure bag fabrication method is feasible.

Bauer, J. L.↗
NASA NTRS1981

Optical processing for landmark identification

A study of optical pattern recognition techniques, available components and airborne optical systems for use in landmark identification was conducted. A data base of imagery exhibiting multisensor, seasonal, snow and fog cover, exposure, and other differences was assembled. These were successfully processed in a scaling optical correlator using weighted matched spatial filter synthesis. Distinctive data classes were defined and a description of the data (with considerable input information and content information) emerged from this study. It has considerable merit with regard to the preprocessing needed and the image difference categories advanced. A optical pattern recognition airborne applications was developed, assembled and demontrated. It employed a laser diode light source and holographic optical elements in a new lensless matched spatial filter architecture with greatly reduced size and weight, as well as component positioning toleranced.

Casasent, D.↗
NASA NTRS1982

Landing induced dust clouds on Venus and Mars

Spacecraft landings on Mars and Venus provide an opportunity to seek and discover transient dust phenomena with various instruments, and to make inferences about local-scale surface modification processes. The present study is concerned with such dust phenomena. In addition, an attempt is made to relate all of the landing sites on Venus to each other in terms of dust phenomena. On Mars a difference in the magnitude of dust effects was observed between the Viking Lander 1 (VL-1) and Viking Lander 2 (VL-2) sites, which is due to either a particle size variation, or the degree of surface blockiness. It appears that the blocks at VL-2 have somewhat protected the surface fines from being raised by retroengine exhaust. The Venera 10 panorama contains a zone of darkening similar to that in the VL-1 zone.

Garvin, J. B.↗
NASA NTRS1984

Alternative experiments using the geophysical fluid flow cell

This study addresses the possibility of doing large scale dynamics experiments using the Geophysical Fluid Flow Cell. In particular, cases where the forcing generates a statically stable stratification almost everywhere in the spherical shell are evaluated. This situation is typical of the Earth's atmosphere and oceans. By calculating the strongest meridional circulation expected in the spacelab experiments, and testing its stability using quasi-geostrophic stability theory, it is shown that strongly nonlinear baroclinic waves on a zonally symmetric modified thermal wind will not occur. The Geophysical Fluid Flow Cell does not have a deep enough fluid layer to permit useful studies of large scale planetary wave processes arising from instability. It is argued, however, that by introducing suitable meridional barriers, a significant contribution to the understanding of the oceanic thermocline problem could be made.

Hart, J. E.↗
NASA NTRS1982

The numerical design of a spherical baroclinic experiment for Spacelab flights

The near-zero G environment of Spacelab is the basis of a true spherical experimental model of synoptic scale baroclinic atmospheric processes, using a radial dielectric body force analogous to gravity over a volume of liquid within two concentric spheres. The baroclinic motions are generated by corotating the spheres and imposing thermal boundary conditions, such that the liquid is subjected to a stable radial gradient and a latitudinal gradient. Owing to mathematical difficulties associated with the spherical geometry, quantitative design criteria can be acquired only by means of numerical models. The procedure adopted required the development of two computer codes based on the Navier-Stokes equations. The codes, of which the first calculates axisymmetric steady flow solutions and the second determines the growth or decay rates of linear wave perturbations with different wave numbers, are combined to generate marginal stability curves.

Fowlis, W. W.↗
NASA NTRS1984

Integrated analysis of remote sensing products from basic geological surveys

Recent advances in remote sensing led to the development of several techniques to obtain image information. These techniques as effective tools in geological maping are analyzed. A strategy for optimizing the images in basic geological surveying is presented. It embraces as integrated analysis of spatial, spectral, and temporal data through photoptic (color additive viewer) and computer processing at different scales, allowing large areas survey in a fast, precise, and low cost manner.

Dasilvafagundesfilho, E.↗
NASA NTRS1984

Vertical transport in the atmosphere: Measurement capabilities and requirements of VHF radars, part 1.6A

Mass exchange, mixing on transport in the atmosphere involves reversible processes, i.e., any kind of organized motions such as wave and large scale flows, and nonreversible processes, i.e., molecular and turbulent diffusion. Without evaluating in detail the relative efficiency of these processes, an attempt is made to summarize those phenomena which can be qualitatively (and eventually also quantitatively) observed with VHF radars. Only mixing in the vertical direction is considered, since this appears to be the essential part of transport processes to which VHF radars can contribute better understanding. Mixing processes in the troposphere are discussed. Possible contributions of VHF radars to the study the mass exchange processes between the troposphere and stratosphere are studied. Transport in the middle atmosphere is briefly summarized, since it is in principle similar to transport in the lower atmosphere.

Rottger, J.↗
NASA NTRS1985

Transport of ozone in the middle stratosphere - Evidence for planetary wave breaking

Data from the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS) for the period October 25, 1978-May 28, 1979 are used in a descriptive study of ozone variations in the middle stratosphere. It is shown that the ozone distribution is strongly influenced by irreversible deformation associated with large amplitude planetary-scale waves. This process, which has been described by McIntyre and Palmer as planetary wave breaking, takes place throughout the 3-30 mb layer, and poleward transport of ozone within this layer occurs in narrow tongues drawn on the tropics and subtropics in association with major and minor warming events. These events complement the zonal mean diabatic circulation in producing significant changes in the total column amount of ozone.

Leovy, C. B.↗
NASA NTRS1983

Carbonaceous chondrites: Early irradiation and Pu-244 fission records

The carbonaceous meteorites were studied. The studies which were conducted have evolved from investigations of early irradiation to mineralogic and petrologic studies of refractory inclusions and to an examination of the time scales of alteration processes on the parent bodies. The attached listing of papers and abstracts provide the details.

Macdougall, J. D.↗