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.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
The surface of a metallic base system is initially coated with a metallic alloy layer that is ductile and oxidation resistant. An aluminide coating is then applied to the metallic alloy layer. The chemistry of the metallic alloy layer is such that the oxidation resistance of the subsequently aluminized outermost layer is not seriously degraded.
An extensive examination of ellipsometric equations for anisotropic surfaces and films is reported. It is shown that the reflection matrix can be calculated by writing Maxwell's equations in 6 x 6 matrix form and by applying appropriate boundary conditions at proper points in the development of the formalism, reducing the equation for the propagation of light to an eigenvalue problem using a 4 x 4 matrix.
Quantitative measurement of X-ray images of bonded power-transistor chips is accomplished by using light meter, which determines percentage of voids in bond.
A design automated approach used to develop thick-film hybrid packages is described. The hybrid packages produced combine thick-film and silicon on sapphire (SOS) laser surface interaction technologies to bring the on-chip performance level of SOS to the subsystem level. Packing densities are improved by a factor of eight over ceramic dual in-line packing; interchip wiring capacitance is low. Due to significant time savings, the design automated approach presented can be expected to yield a 3:1 reduction in cost over the use of manual methods for the initial design of a hybrid.
Teflon grommet, cast in place, is easily installed and compatible with honeycomb structural integrity. After casting, grommet blank had only minimum hole size; however, opening can be enlarged by drilling to accommodate larger range of cable diameters. Since grommet is installed flush with adjacent mounting surfaces, it cannot fall out.
An experimental apparatus was constructed and utilized in conjunction with both a solar simulator and actual sunlight to test and evaluate various solar panel coatings, panel designs, and scaled-down collector subsystems. Data were taken by an automatic digital data acquisition system and reduced and printed by a computer system. The solar collector test setup, data acquisition system, and data reduction and printout systems were considered to have operated very satisfactorily. Test data indicated that there is a practical or useful limit in scaling down beyond which scaled-down testing cannot produce results comparable to results of larger scale tests. Test data are presented as are schematics and pictures of test equipment and test hardware.
Assemblies for cryogenic applications are shockproof and vibrationproof.
Supercooling of silicon-tin alloy melts was studied. Values as high as 78 C at 1100 C and 39 C at 1200 C were observed, corresponding to supersaturation parameter values 0.025 and 0.053 at 1050 C and 1150 C, respectively. The interaction of tin with silane gas streams was investigated over the temperature range 1000 to 1200 C. Single-pass conversion efficiencies exceeding 30% were obtained. The growth habit of spontaneously-nucleated surface growth was determined to be consistent with dendritic and web growth from singly-twinned triangular nucleii. Surface growth of interlocking silicon crystals, thin enough to follow the surface of the liquid and with growth velocity as high as 5 mm/min, was obtained. Large area single-crystal growth along the melt surface was not achieved. Small single-crystal surface growth was obtained which did not propagate beyond a few millimeters.
Explore the source record for details and available documents.
Approach uses polyimide film bonded to aluminum plate using epoxy-impregnated fiberglass cloth as insulating layer. Because film is nonporous, problems due to voids are eliminated.
Explore the source record for details and available documents.
It was found that the in situ treatment of 001-plane single-crystal films of MgO (prepared by epitaxial growth from the vapor phase) at high temperatures with a jet of oxygen will produce a surface that is almost equivalent, for epitaxial studies, to surfaces with the same orientation prepared by vacuum cleavage of bulk single crystals. The effectiveness of the process is demonstrated by its impact on the epitaxy of silver.
The exchange of O2 for H2O, analogous to that recorded on Mars by the Viking GEX experiment, has been observed on humidifying powdered beta-MnO2 (pyrolusite) which had been irradiated by UV in a humidified analog of the Martian atmosphere. Pyrolusite irradiated in a dry atmosphere did not release O2 on humidification. The XPS spectra of Mn and O of the reactive pyrolusite were shifted toward higher binding energies during UV irradiation. These shifts are consistent with the creation of a surface layer of a Mn(V) or Mn(VI) compound. The destruction of such a layer on humidification could account for the observed O2 release. Although manganese has not been identified in the Martian regolith, the upper limit of the Mn concentration is sufficiently high that O2 release from pyrolusite could have been responsible for the results of the Viking GEX experiment.
System recently tested uses acoustic waves to levitate liquid drops, millimeter-sized glass microballoons, and other objects for coating by vapor deposition or capillary attraction. Cylindrical contactless coating/handling facility employs a cylindrical acoustic focusing radiator and a tapered reflector to generate a specially-shaped standing wave pattern. Article to be processed is captured by the acoustic force field under the reflector and moves as reflector is moved to different work stations.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
A proposal for a standard specifications listing covering requirements for silicon wafers used in solar cell manufacturing is outlined. The specific contents of the general requirements specifications include: ordering information; dimensions and permissible variations; material and manufacture; physical parameters; sampling; test methods; certification; and packaging and marking.
Array of tiny probes tests complex printed circuit boards prior to mounting of microcircuit chips and other active and passive components. Insertion and alignment of board, performance of entire computer-controlled test, and printing of results requires about a minute; performed manually same tests require as much as 30 hours.