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At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS1971

Simulated space environment tests on cadmium sulfide solar cells

Cadmium sulfide (Cu2s - CdS) solar cells were tested under simulated space environmental conditions. Some cells were thermally cycled with illumination from a Xenon-arc solar simulator. A cycle was one hour of illumination followed immediately with one-half hour of darkness. In the light, the cells reached an equilibrium temperature of 60 C (333 K) and in the dark the cell temperature dropped to -120 C (153 K). Other cells were constantly illuminated with a Xenon-arc solar simulator. The equilibrium temperature of these cells was 55 C (328 K). The black vacuum chamber walls were cooled with liquid nitrogen to simulate a space heat sink. Chamber pressure was maintained at 0.000001 torr or less. Almost all of the solar cells tested degraded in power when exposed to a simulated space environment of either thermal cycling or constant illumination. The cells tested the longest were exposed to 10.050 thermal cycles.

Clarke, D. R.↗
NASA NTRS1973

Product distributions and rate constants for ion-molecule reactions in water, hydrogen sulfide, ammonia, and methane

The thermal energy, bimolecular ion-molecule reactions occurring in gaseous water, hydrogen sulfide, ammonia, and methane have been identified and their rate constants determined using ion cyclotron resonance methods. Absolute rate constants were determined for the disappearance of the primary ions by using the trapped ion method, and product distributions were determined for these reactions by using the cyclotron ejection method. Previous measurements are reviewed and compared with the results using the present methods. The relative rate constants for hydrogen-atom abstraction, proton transfer, and charge transfer are also determined for reactions of the parent ions.

Huntress, W. T., Jr.↗
NASA NTRS1974

Some aspects of optical feedback with cadmium sulfide and related photoconductors

A primary limitation of many solid state photoconductors used in electro-optical systems is their slow response in converting varying light intensities into electrical signals. An optical feedback technique is presented which can extend the frequency response of systems that use these detectors by orders of magnitude without adversely affecting overall signal-to-noise ratio performance. The technique is analyzed to predict the improvement possible and a system is implemented using cadmium sulfide to demonstrate the effectiveness of the technique and the validity of the analysis.

Katzberg, S. J.↗
NASA NTRS1975

Relation of lineaments to sulfide deposits: Bald Eagle Mountain, Centre County, Pennsylvania

The author has identified the following significant results. Discrete areas of finely-fractured and brecciated sandstone float are present along the crest of Bald Mountain and are commonly sites of sulfide mineralization, as evidenced by the presence of barite and limonite gossans. The frequency distributions of the brecciated float as the negative binomial distribution supports the interpretation of a separate population of intensely fractured material. Such zones of concentrated breccia float have an average width of one kilometer with a range from 0.4 to 1.6 kilometers and were observed in a quarry face to have subvertical dips. Direct spatial correlation of the Landsat-derived lineaments to the fractured areas on the ridge is low; however, the mineralized and fracture zones are commonly assymetrical to the lineament positions. Such a systematic dislocation might result from an inherent bias in the float population or could be the product of the relative erosional resistance of the silicified material in the mineralized areas in relation to the erosionally weak material at the stream gaps.

Mcmurtry, G. J.↗
NASA NTRS1974

Absolute rate parameters for the reaction of ground state atomic oxygen with carbonyl sulfide

The rate parameters for the reaction of O(3P) with carbonyl sulfide, O(3P) + OCS yields CO + SO, have been determined directly by monitoring O(3P) using the flash photolysis-resonance fluorescence technique. The value for reaction rate was measured over a temperature range of 263-502 K and the data were fitted to an Arrhenius expression with good linearity. A comparison of the present results with those from previous studies of this reaction is also presented.

Klemm, R. B.↗