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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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Small, low-cost comparator with 24-bit-precision yields ratio signal from pair of analog or digital input signals. Arithmetic logic chips (bit-slice) sample two 24-bit analog-to-digital converters approximately once every millisecond and accumulate them in two 24-bit registers. Approach readily modified to arbitrary precision.
A graphics subsystem retrofit design for the turbojet blade vibration data acquisition system is presented. The graphics subsystem will operate in two modes permitting the system operator to view blade vibrations on an oscilloscope type of display. The first mode is a real-time mode that displays only gross blade characteristics, such as maximum deflections and standing waves. This mode is used to aid the operator in determining when to collect detailed blade vibration data. The second mode of operation is a post-processing mode that will animate the actual blade vibrations using the detailed data collected on an earlier data collection run. The operator can vary the rate of payback to view differring characteristics of blade vibrations. The heart of the graphics subsystem is a modified version of AMD's ""super sixteen'' computer, called the graphics preprocessor computer (GPC). This computer is based on AMD's 2900 series of bit-slice components.
The current work in progress for the SAGA project are described. The highlights of this research are: a parser independent SAGA editor, design for the screen editing facilities of the editor, delivery to NASA of release 1 of Olorin, the SAGA parser generator, personal workstation environment research, release 1 of the SAGA symbol table manager, delta generation in SAGA, requirements for a proof management system, documentation for and testing of the cyber pascal make prototype, a prototype cyber-based slicing facility, a June 1984 demonstration plan, SAGA utility programs, summary of UNIX software engineering support, and theorem prover review.
The applications of the photo-activated, the CCD-addressed, and the variable-grating mode liquid crystal light valves (LCLVs) to optical data processing are described. These applications include image correlation, level slicing, spectral analysis and correlation, bi-spectral image division, and matrix-matrix multiplication.
Several case studies are examined in an attempt to relate Visible infrared spin scan radiometers Atmospheric Sounder (VAS) water vapor channel radiance data to atmospheric moisture. Since the 6.7 micrometer channel detects radiation emitted by atmospheric water vapor from a rather thick layer, a scheme is developed which weighted rawinsonde observations of relative humidity in a similar manner. A comparison of the two fields (weighted relative humidity values from gridded rawinsonde observations and the VAS water vapor image) indicates that even when mesoscale data are used, the technique only presented a smooth representation of the radiance field. This weighting function is dependent on both the temperature and moisture distribution of the atmosphere. Cross sections of relative humidity from the mesoscale rawinsondes are produced which sliced the water vapor imagery in particularly interesting regions (areas of high and low blackbody temperatures). Comparisons are then made between the cross sections and the variations in the VAS radiance data along the cross section line. Bright regions in the water vapor imagery (cold blackbody temperatures) are often associated with thin layers of high relative humidity or thick layers of only moderately moist air. The reverse also applies, i.e., dark regions (warm blackbody temperatures) in the imagery corresponded well with very dry regions in the cross sections.
Six slices of ultra-pure germanium were irradiated with thermal neutron fluences between 7.5 x 10 to the 16th and 1.88 x 10 to the 18th per sq cm. After thermal annealing the resistivity was measured down to low temperatures (less than 4.2 K) and found to follow the relationship rho = rho sub 0 exp(Delta/T) in the hopping conduction regime. Also, several junction FETs were tested for noise performance at room temperature and in an insulating housing in a 4.2 K cryostat. These FETs will be used as first stage amplifiers for neutron-transmutation-doped germanium bolometers.
The efficient utilization of materials is critical to certain device applications such as silicon for photovoltaics or diodes and gallium-gadolinium-garnet for memories. A variety of slicing techniques has been investigated to minimize wafer thickness and wafer kerf. This paper presents the results of analyses of ID wafering of rotated ingots based on predicted fracture behavior of the wafer as a result of forces during wafering and the properties of the device material. The analytical model indicated that the minimum wafer thickness is controlled by the depth of surface damage and the applied cantilever force. Both of these factors should be minimized. For silicon, a minimum thickness was found to be approximately 200 x 10 - 6th m for conventional sizes of rotated ingot wafering. Fractures through the thickness of the wafer rather than through the center supporting column were found to limit the minimum wafer thickness. The model suggested that the use of a vacuum chuck on the wafer surface to enhance cleavage fracture of the center supporting core and, with silicon, by using 111-line-type ingots could have potential for reducing minimum wafer thickness.
Results of a study demonstrating the feasibility of broadband and speckle-free projective imaging of a complex shaped scattering object in the 6-17 GHz range with centimeter resolution are presented. It is shown how angular, spectral, and polarization diversities can be combined in the data acquisition process with a unique target-derived reference technique to access the three-dimensional Fourier space of the scatterer cost-effectively. Imagea retrieval algorithms, based on the projection slice theorem and knowledge of object symmetry, are utilized in obtaining images of a model aircraft with near optical resolution. The implications for high-resolution three-dimensional tomographic imaging radar networks are discussed.
The advent of Very Large Scale Integration (VLSI) technology has rendered the gate level model impractical for many simulation activities critical to the design automation process. As an alternative, an approach to the modeling of VLSI devices at the chip level is described, including the specification of modeling language constructs important to the modeling process. A model structure is presented in which models of the LSI devices are constructed as single entities. The modeling structure is two layered. The functional layer in this structure is used to model the input/output response of the LSI chip. A second layer, the fault mapping layer, is added, if fault simulations are required, in order to map the effects of hardware faults onto the functional layer. Modeling examples for each layer are presented. Fault modeling at the chip level is described. Approaches to realistic functional fault selection and defining fault coverage for functional faults are given. Application of the modeling techniques to single chip and bit slice microprocessors is discussed.
Attachment for reciprocating power-saw maintains nearly constant cutting pressure even though kerf length varies. Attachment developed for wire saws used to slice cylindrical silicon ingots into wafers for semiconductor devices. By maintaining constant pressure, attachment helps to ensure smooth, flat, uniform wafers. Principle adaptable to straight, toothed saws as well as to wire saws.
Probable dust counterparts of arching structures are investigated in two cases: (1) the Eridanus expanding shell; and (2) the extended Sco-Cen feature. Color excess data may be used to derive distance and dimension estimates of these structures. Color excesses from two areas SA 121 and SA 144 situated on the position of the 3.2 to 6.3 km/s velocity-slice are applied. Some stratification of the color excesses is noticed for both areas but extreme patchiness typifies particularly the dust in the SA 144 region.
A chemical means of creating the proper kind of light collection texture on (100) silicon slices is discussed. Texturing of (100) silicon surfaces in sodium or potassium hydroxides occurs by the growth of a reaction product in a random array of surface sites, which leads to pyramids remaining at the sites after other parts of the surface dissolve away. A new texture-promoting influence, a proximity effect, was discovered in this work. An attempt was made to quantify the various promotional effects. The purpose of the present paper is to: (1) explain in detail the attempt at understanding and quantifying texturing; (2) give an experimental description with observations on the proximity effect and the effect of additions of water glass that were discovered during this work; and (3) show that the precipitate or growth models account for almost all of the known promotional effects.
A modified Claisen condensation with sliced sodium at a higher temperature was recommended for the production of ungranulated charcoal. A new ninhydrin production method by oxidation of benzaldiketohydrinden using available reagents was tried and was unsuccessful. Triketohydrinden was obtained by boiling ninhydrin in acetic acid anhydrides.
A summary of single event upset data for 42 device types (including RAMs, 4-bit slices, microprocessors, 4-bit counters, and flip-flops) studied at 11 different accelerator tests (performed chiefly with the Berkeley 88-inch cyclotron and the Cal Tech Van de Graaff) is presented. All bipolar and NMOS RAMs were found to be SEU sensitive, some with very low LET thresholds. Some CMOS or CMOS/SOS RAMs were hard; and the CMOS microprocessors were hard, but the bipolar and NMOS microprocessors were soft. Several devices were found to exhibit a cross section that depends strongly on LET, even when the LET is well above the LET threshold. A ranking of hardness is presented for the logic devices tested.
The presence of high-energy protons in cosmic rays, solar flares, and trapped radiation belts around Jupiter poses a threat to the Galileo project. Results of a test of 10 device types (including 1K RAM, 4-bit microP sequencer, 4-bit slice, 9-bit data register, 4-bit shift register, octal flip-flop, and 4-bit counter) exposed to 590 MeV protons at the Swiss Institute of Nuclear Research are presented to clarify the picture of SEU response to the high-energy proton environment of Jupiter. It is concluded that the data obtained should remove the concern that nuclear reaction products generated by protons external to the device can cause significant alteration in the device SEU response. The data also show only modest increases in SEU cross section as proton energies are increased up to the upper limits of energy for both the terrestrial and Jovian trapped proton belts.
Several forms of polycrystalline silicon, mostly from cast ingots, (including UCP, SILSO and HEM) were studied. On typical slices, localized properties were studied in two ways. Small area (about 2.5 sq mm) mesa diodes were formed, and localized photovoltaic properties were measured. Also a small area (about .015 sq mm) light spot was scanned across the cells; the light spot response was calibrated to measure local diffusion length directly. Using these methods, the effects of grain boundaries, or of intragrain imperfections were correlated with cell performance. Except for the fine grain portion of SILSO, grain boundaries played only a secondary role in determining cell performance. The major factor was intra-grain material quality and it varied with position in ingots and probably related to solidification procedure.
Several case studies are examined in an attempt to relate Visible infrared spin scan radiometers Atmospheric Sounder (VAS) water vapor channel radiance data to atmospheric moisture. Since the 6.7 micrometer channel detects radiation emitted by atmospheric water vapor from a rather thick layer, a scheme is developed which weighted rawinsonde observations of relative humidity in a similar manner. A comparison of the two fields (weighted relative humidity values from gridded rawinsonde observations and the VAS water vapor image) indicates that even when mesoscale data are used, the technique only presented a smooth representation of the radiance field. This weighting function is dependent on both the temperature and moisture distribution of the atmosphere. Cross sections of relative humidity from the mesoscale rawinsondes are produced which sliced the water vapor imagery in particularly interesting regions (areas of high and low blackbody temperatures). Comparisons are then made between the cross sections and the variations in the VAS radiance data along the cross section line. Bright regions in the water vapor imagery (cold blackbody temperatures) are often associated with thin layers of high relative humidity or thick layers of only moderately moist air. The reverse also applies, i.e., dark regions (warm blackbody temperatures) in the imagery corresponded well with very dry regions in the cross sections.
The use of the resonant Doppler velocimeter for flow visualization in a free supersonic nitrogen jet is demonstrated experimentally. In the experiment reported here, room-temperature nitrogen at 12.7 psi expands through a Mach 3.4 converging diverging nozzle into a plenum chamber; small amount of sodium is injected through a heated needle centered 0.5-in. upstream of the nozzle throat. The beam of a single frequency dye laser is expanded into a sheet of light with a cylindrical beam expander and directed counter to the jet to spatially resolve any slice across the core of the flow. By tuning the laser to different frequencies, particular velocity and density fields can be highlighted.