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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 1,567 records · Page 87
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Developments in electronic imaging techniques; Proceedings of the Seminar-in-Depth, San Mateo, Calif., October 16, 17, 1972.

Capabilities and limitations of infrared imaging systems are discussed, and a real-time simulator for image data systems is described. Ultrahigh resolution electronic imaging and storage with the return beam vidicon is treated, and a description is given of an electron-lens for opaque photocathodes. Ground surveillance with an active low light level TV, digital processing of Mariner 9 TV data, image enhancement by holography, and application of data compression techniques to spacecraft imaging systems are given attention. Individual items are announced in this issue.

Zirkind, R.↗
NASA NTRS1973

Radio interferometry depth sounding. II.

Experimental results from an analog scale model and from field tests on two glaciers using radio-frequency interferometry (RFI) are interpreted on the basis of previously described theoretical results. The RFI technique is found to be a practical method with which to study layering in low-loss dielectrics. Three parameters of the upper layer can be estimated from the data: the dielectric constant, the loss tangent, and an estimate of the thickness to a reflector. The method is an inexpensive way to sound ice sheets less than a few hundred meters thick, and could be used to study low-loss layers on the moon.

Rossiter, J. R.↗
NASA NTRS1975

Reaction of sulfur dioxide with modified 440C, studied by Auger electron spectroscopy and depth profiling

Auger electron spectroscopy and sputtering were used to study the interaction of SO2 with modified 440C, which is a nominally 77-wt%-Fe, 14-wt%-Cr, and 4-wt%-Mo bearing steel with C, S, Si, Ni, V, P, and Mn making up the balance. The sample was polycrystalline. Three temperatures were used: room temperature, 500 C, and 600 C. The reaction time was varied from 30 minutes to 2 hours. A surface cleaned of oxides was the starting point for each reaction. For reactions at 500 C, the major constituents Cr, O, Fe, and S were present in the surface film. At 600 C, the principal constituents of the film were Cr, O, and S with no Fe present. Therefore, a transition in film composition occurred between 500 and 600 C. Oxides were the primary constituents of the films at both temperatures. Room-temperature reactions indicated that SO2 adsorbed dissociatively, with approximately equal quantities of S and O on the surface. For the same reaction time (1 hr) and pressure, a strong temperature dependence of film thickness was observed. The film formed at 600 C was approximately seven times thicker than that formed at 500 C.

Ferrante, J.↗
NASA NTRS1974

Evaluation of the energy transfer in the char zone during ablation. Part 2: In-depth response of ablative composites, volume 1

The decomposition of ablative composites is described along with the transport phenomena of pyrolysis gases which result from the decomposition of these plastics as they flow through the porous char of char-forming ablators. The pyrolysis products are those formed by the thermal degradation of nylon-phenolic resin and silicone elastomer composites. Emphasis is placed on the nature and extent of chemical reactions of the pyrolysis products and the char, along with the energy absorbed by the combined pyrolysis and char zone. Chemical reactions with thermodynamically consistent kinetic data are determined in order to develop a realistic analysis for predicting the thermal performance of ablative heat shields.

Pike, R. W.↗
NASA NTRS1974

Water depth penetration film test

As part of the National Aeronautics and Space Administration Earth Resources Program, a comparative and controlled evaluation of nine film-filter combinations was completed to establish the relative effectiveness in recording water subsurface detail if exposed from an aerial platform over a typical water body. The films tested, with one exception, were those which prior was suggested had potential. These included an experimental 2-layer positive color film, a 2-layer (minus blue layer) film, a normal 3-layer color film, a panchromatic black-and-white film, and a black-and-white infrared film. Selective filtration was used with all films.

Lockwood, H. E.↗
NASA NTRS1975

Microwave emission spectrum of the moon - Mean global heat flow and average depth of the regolith

Earth-based observations of the lunar microwave brightness temperature spectrum at wavelengths between 5 and 500 centimeters, when reexamined in the light of physical property data derived from the Apollo program, tentatively support the high heat flows measured in situ and indicate that a regolith thickness between 10 and 30 meters may characterize a large portion of the lunar near side.

Keihm, S. J.↗
NASA NTRS1974

Depth of immersion as a determinant of the natriuresis of water immersion

The current study was undertaken to further assess the contribution of an immersion-induced hydrostatic pressure gradient on the redistribution of blood volume. The rate of sodium excretion by seated subjects was significantly increased by water immersion up to the chest and neck compared to waist immersion and controls. These results are consistent with the hypothesis that whereas immersion to the level of the diaphragm merely cancels the intravascular hydrostatic pressure gradient by providing an identical external gradient, immersion above the diaphragm level results in increased water pressure which tends to favor a shift in blood volume from the lower extremities.

Epstein, M.↗