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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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A technology review committee from NASA, the U.S. Department of Energy (DOE), and the Air Force Research Lab, was formed to assess solar cell and array technologies required for future NASA science missions.
Irradiation damage of drift-field solar cells by low energy protons - computer analysis of current-voltage and spectral response data
The tomato (Lycopersicon esculentum, Mill.) mutant diageotropica (dgt) exhibits biochemical, physiological, and morphological abnormalities that suggest the mutation may have affected a primary site of auxin perception or action. We have compared two aspects of the auxin physiology of dgt and wild-type (VFN8) seedlings: auxin transport and cellular growth parameters. The rates of basipetal indole-3-acetic acid (IAA) polar transport are identical in hypocotyl sections of the two genotypes, but dgt sections have a slightly greater capacity for IAA transport. 2,3,5-Triiodobenzoic acid and ethylene reduce transport in both mutant and wild-type sections. The kinetics of auxin uptake into VFN8 and dgt sections are nearly identical. These results make it unlikely that an altered IAA efflux carrier or IAA uptake symport are responsible for the pleiotropic effects resulting from the dgt mutation. The lack of auxin-induced cell elongation in dgt plants is not due to insufficient turgor, as the osmotic potential of dgt cell sap is less (more negative) than that of VFN8. An auxin-induced increase in wall extensibility, as measured by the Instron technique, only occurs in the VFN8 plants. These data suggest dgt hypocotyls suffer a defect in the sequence of events culminating in auxin-induced cell wall loosening.
The phase behavior of carbon at high pressure and the search for carbon structures denser than diamond has been explored for decades showing large discrepancies, with many fundamental questions remaining unresolved. Here we show evidence of melting above the graphite-diamond-liquid (GDL) triple point (~13 GPa, 4000 K) up to 50 GPa on samples recovered from single flash-heating events using spectroscopic and electron microscopic methods. The results show that for all pressures, diamond melts below the triple point temperature contradicting previous studies, most of which predict a positive slope of the melting curve.
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Bonding radii of ribosomes crystal packing between forms found in chromatoid bodies of Entamoeba invadens and mitotic cells of chilled chick embryos
Volt-ampere characteristics improvement and life testing of electrodes for hydrogen oxygen fuel cells
Quality control program and cell construction flow chart for development of 50 ampere hour thermal cell with copper oxide cathode
Test results prove nickel carbide or nitride, nickel-cobalt carbide, titanium carbide or nitride, and intermetallic compounds of the transition or noble metals to be efficient electrocatalysts for oxygen reduction in alkaline electrolytes in low temperature fuel cells.
High altitude solar cell and radiometer calibrations using balloon techniques
Maintaining current flow through solar cells with open connection using shunting diode
High altitude solar cell and radiometer calibrations using balloon techniques
The silicon-on-ceramic (SOC) process uses inexpensive ceramic substrates to provide supported growth of silicon from the melt. The conditions for unidirectional solidification, the grain structure and other properties are quite similar to those of EFG silicon ribbon. Solar cells with interdigital electrodes have demonstrated AMl conversion efficiencies (active area) of 7.8% without AR coatings and 10.1% efficiencies with an AR coating of SiO. Mathematical modeling of the series resistance of cells shows the feasibility of making electrical contact to the base layer of the cell through slots in the substrate. However, series resistance in the base layer sets an upper limit on slot spacing for efficient cell performance.
An analysis was performed to determine the economic feasibility of a concentrating spectrophotovoltaic orbital electrical power generation system. In this system dichroic beam-splitting mirrors are used to divide the solar spectrum into several wavebands. Absorption of these wavebands by solar cells with matched energy bandgaps increases the cell efficiency while decreasing the amount of heat which must be rejected. The optical concentration is performed in two stages. The first concentration stage employs a Cassegrain-type telescope, resulting in a short system length. The output from this stage is directed to compound parabolic concentrators which comprise the second stage of concentration. Ideal efficiencies for one-, two-, three-, and four-cell systems were calculated under 1000 sun, AMO conditions, and optimum energy bands were determined. Realistic efficiencies were calculated for various combinations of Si, GaAs, Ge and GaP. Efficiencies of 32 to 33 percent were obtained with the multicell systems. The optimum system consists of an f/3.5 optical system, a beam splitter to divide the spectrum at 0.9 microns, and two solar cell arrays, GaAs and Si.
The activities of the NASA Office of Solar Terrestrial System are reviewed. Consideration is given to solar heating and cooling, wind energy systems, solar cells, and the solar thermal power program.
Standard Transistor Array (STAR) design system is semicustom approach to generating random-logic integrated MOS digital circuits. Primary program in STAR system is CAPSTAR, STAR Cell Arrangement Program. CAPSTAR is augmented by automatic routining program, Display program and library of logic cells.
An investigation was conducted to evaluate the welding and temperature cycle testing of large area 5.9 x 5.9 wraparound silicon solar cells utilizing printed circuit substrates with SSC-155 interconnect copper metals and the LMSC Infrared Controlled weld station. An initial group of 5 welded modules containing Phase 2 developmental 5.9 x 5.9 cm cells were subjected to cyclical temperatures of + or 80 C at a rate of 120 cycles per day. Anomalies were noted in the adhesion of the cell contact metallization; therefore, 5 additional modules were fabricated and tested using available Phase I cells with demonstrated contact integrity. Cycling of the later module type through 12,000 cycles indicated the viability of this type of lightweight flexible array concept. This project demonstrated acceptable use of an alternate interconnect copper in combination with large area wraparound cells and emphasized the necessity to implement weld pull as opposed to solder pull procedures at the cell vendors for cells that will be interconnected by welding.
The development of high efficiency solar cells on a silicon web is discussed. Heat treatment effects on web quality; the influence of twin plane lamellae, trace impurities and stress on minority carrier lifetime; and the fabrication of cells are discussed.