SEARCH · Engineering Papers
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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Burning solid ammonium perchlorate composite propellants surface structure observation to assess heterogeneous or subsurface reactions, using scanning electron microscope
Al and Be single particles combustion in various oxidizers, using pulsed Nd-glass laser and Xe flash heating device and scanning electron microscope
Squid head cartilage properties in terms of light and electron microscopic appearance, amino acid composition and X ray diffraction
Auger electron velocity analyzer for use with scanning electron microscope to identify low concentrations of elements on surfaces of semiconductor devices
Substructures and properties of Ni, Chromel A, Inconel 600 and TD-NiCr following explosive shock load deformation, using electron microscope
Electron microscopic studies of nerve membrane fine structure, discussing cell membrane multienzyme and macromolecular energy and information transduction, protein synthesis and nucleic acids interrelations
Scanning electron microscope and petrographic observations of glass particles from Apollo 12 lunar soil sample, revealing surface features and origin
Scanning electron microscope for poor metallization detection in manufacturing cycle of semiconductor devices
Ion bombardment thinning apparatus for preparing electron microscope foils of inorganic nonmetallic samples including ceramics, minerals and rocks
Apollo 12 lunar soil and breccia core tube and surface samples optical and electron microscope and microprobe analysis, relating data to geologic processes
Lunar breccia sample matrix composition characteristics examination by transmission electron microscope, suggesting condensation from rock volatilized by meteorite impact heat
Particle size and shape distributions of Apollo 12 lunar fines by computer evaluation of scanning electron microscope images
The transmission electron microscope was used to investigate the nature of the matrix in two samples of lunar breccia. This matrix is composed largely of tiny (0.5 microns) grains of unaltered glass which are plastically fitted against one another, and tightly welded to the clastic fragments with which they are in contact. The breccias have an open framework of angular clastic particles composed mainly of anorthositic, basaltic and glassy fragments. Most of the anorthositic fragments have been shock metamorphosed. Over half of the glassy clasts, and also the former diaplectic glass particles produced from shocked plagioclase, were partly or wholly devitrified before inclusion in the present breccias. It is concluded that each breccia was deposited from a hot basesurge cloud of impact debris, and the tiny bits of glass in the matrix condensed from rock that was volatilized by the heat of major meteorite impact.
Tin was melted in a heating assembly secured to the arm of a centrifuge. The furnace was allowed to pivot and reach its equilibrium angle of swing for the gravity force being experienced. The crucible was cooled during rotation to allow the growth of single crystals. The crystals were etched for the purpose of observing the growth striations. Slices were removed from some of the crystals to permit observation of the striations in the interior. Visual analyses were made with a scanning electron microscope. Preliminary conclusions relating the appearance of the striations to gravity forces and the affected growth mechanisms are presented. Further experiments that will verify these conclusions and determine other gravity effects are proposed.
Determination of the number of micrometeoroid impact craters on the camera provided an opportunity to make a sensitive direct measurement of the flux of interplanetary dust particles impacting the lunar surface. Optical and scanning electron microscope studies were performed. Low velocity impact and flux analyses are presented.
Sections C and E of the unpainted, polished aluminum tubing from the strut of the radar altimeter and Doppler velocity sensor were examined in a transmission electron microscope for micrometeorite damage and ion bombardment. Both sections were contaminated and eroded on one side; it is suggested that these conditions were caused by sandblasting by lunar dust and retrorocket plume contamination during Surveyor 3 landing. Microcraters of different configurations were found on the bright sides of the tubes. Several degrees of violence were involved in the formation of the craters, and the particle size could be responsible for some differences. All micropits found were on the bright areas and data indicate 0.2 hypervelocity impact/sq cm and 2/sq cm for other types of craters. The greatest degree of damage resulted from particle impact and was limited to a maximum depth of 2 microns.
Screws 9 and 23 from Surveyor 3 were examined with a scanning electron microscope for micrometeorite impact features. Six craters on one of the screws appear to be low velocity impact craters, and a flux for about 0.12 sq cm was calculated to be 0.005/sq m/sec for particle diameter or = 1 micron. Two interpretations are considered: (1) The impacts were produced by interplanetary particles and the flux indicates that deviation from the normal distribution exists only for particles below 1 micron in diameter. (2) Most of the craters were produced by secondary lunar debris, and the flux represents the upper limit for interplanetary particles.
Study regions of lattice disorder produced in lithium-doped float-zone melted n/p-type silicon solar cells by irradiation with monoenergetic neutrons at doses between 10 to the 10th and 10 to the 13th per cu cm. The defect regions were revealed by chemically etching the surface of the solar cells and by observing carbon replicas in an electron microscope. It was found that the defect density increased with increasing irradiation dose and increased lithium content, whereas the average defect diameter was found to decrease. From thermal annealing experiments it was found that in the lithium-doped material the defect structure was stable at temperatures between 300 and 1200 K. This was found to be in contrast to the undoped material where at the lowest doses considerable annealing was observed to occur. These results are discussed in terms of the theoretical predictions and models of defect clusters proposed by Gossick (1959) and Crawford and Cleland (1959).