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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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At least 289 records · Page 16
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

The JPL millimeter, submillimeter and microwave line catalog

The catalog includes molecules of interest in the interstellar medium, in planetary atmospheres and in the Earth's atmosphere. Different units than those on the AFGL tape are used. For citing line frequencies in the microwave region. Either the experimental errors or the propagation of errors from the fit are included on the tape. This gives an estimate of how accurate the frequencies are. The intensity units are defined as follows: the logarithm of the intensity unit is the cross section times the frequency in MHz. This is essentially the same unit as on the AFGL tape, but contains fewer factors of the speed of light. The catalog is available to the scientific community either as a tape or on microfiche (filmed in frequency sorted and molecule sorted format).

Pickett, H.↗
NASA NTRS1982

Petrology of dune sand derived from basalt on the Ka'u Desert, Hawaii

Dune sand from the Ka'u Desert, southwest flank of Kilauea volcano, Hawaii, is moderately well-sorted (median = 1.60 Phi, deviation = 0.60, skewness = 0.25, kurtosis = 0.68) and composed mostly of frosted subangular particles of basalt glass ('unfractionated' olivine-normative tholeitte), olivine, lithic fragments (subophitic and intersertal basalts; magnetite-ilmenite-rich basalts), reticular basalt glass, magnetite, ilmenite, and plagioclase, in approximately that order of abundance. Quantitative lithological comparison of the dune sand with sand-sized ash from the Keanakakoi Formation supports suggestions that the dune sand was derived largely from Keanakakoi ash. The dune sand is too well sorted to have been emplaced in its present form by base-surge but could have evolved by post-eruption reworking of the ash.

Gooding, J. L.↗
NASA NTRS1983

Thermionic energy converters

The efficiency of thermionic energy converters is improved by internal distribution of tiny sorted cesium diodes driven by the thermal gradient between the primary emitter and the collector. The tiny, sorted diode distribution comprises protrusions of the emitter material from the main emitter face which contact the main collector face thermally but not electrically. The main collector ends of the protrusions are separated from the main collector by a thin layer of insulation, such as aluminum oxide. The shorted tiny diode distribution augments cesium ionization through internal thermal effects only within the main diode. No electrical inputs are required. This ionization enhancement by the distribution of the tiny shorted diodes not only reduces the plasma voltage drop but also increases the power output and efficiency of the overall thermionic energy converter.

Morris, J. F.↗
NASA NTRS1984

Postprocessing for the UCLA climate model

Postprocessing programs written to analyze the results of a general circulation model are described. The model history data is interpolated to pressure surfaces, converted from 64-bit Cyber words to 32 bit IBM words, and transferred to tape for further analysis. The time average program reads the interpolation output tape and produces 15-day time averages. The model outputs a very detailed record for selected grid points. This data is sent to a tape in Cyber full words. The conversion program changes the format of the tape from 64 bit Cyber words to 32 bit IBM words, processing a month of data at a time. The grid-point history sorting program inputs the converted grid point history tape and sorts it by time. The end product is a tape with a time history of each field for every point. After the PBP data has been stored, it can be plotted. The plotting package is flexible, and allows the choice of fields and grid points. The one-dimensional fields are plotted as functions of time, and a daily summary is also produced. For the two-dimensional fields, time-height cross sections and daily summaries are produced. The model plotting package produces plots for all fields on the time average and pressure tapes. These plots include world maps, polar projections, zonal means, vectors, streamlines, and latitude-height plots.

Abeles, J.↗
NASA NTRS1984

Variation of the auroral Birkeland and current pattern associated with the north-south component of the IMF

In this study, the data set acquired from the vector magnetometer on board MAGSAT during the period October 1979 to June 1980 is examined. Auroral zone crossings were sorted by hourly averaged values of the Interplanetary Magnetic Field. The result is a catalog of sorted data files, from which color-coded magnetic local time invariant latitude plots have been generated that image the auroral Birkeland current pattern, over each prescribed parameter range. These images are used to statistically examine the dynamics of the current pattern. Results indicate that during the periods of B(z) less than 0, the region 1 and 2 current system expands toward lower latitudes accompanied by an expansion of the auroral zones. When B(z) is greater than 0, the region 1 and 2 currents continue to flow with greatly reduced amplitude in the presence of extensive small scale structure.

Bythrow, P. F.↗
NASA NTRS1984

Size dependence of chondrule textural types

Chrondrule textural types were studied for size sorted chondrules from the ordinary chondrites Dhajala, Eston and Chainpur and the CM chondrite Murchison. Aliquot samples from size sorted Dhajala chondrules were studied for their oxygen isotopic composition and chondrules from Weston were studied for their precompaction irradiation records by nuclear track technique. Correlations between chondrule textural types and oxygen isotope or track data were identified. A distinct dependence of chondrule textural type on chondrule size was evident in the data for both Dhajala and Weston chondrules. No significant deviation was noticed in the abundance pattern of nonporphyritic chondrules within individual size fractions in the 200 to 800 micron size interval. Overabundance is found of nonporphyritic chondrules in the 100 to 200 micron size fraction of Murchison chondrules, the trend is not as distinct for Chainpur chondrules. Two hundred microns is suggested as the cutoff size below which radiative cooling is extremely efficient during the chondrule forming process. It is suggested that this offers a possibility for use of physical and chemical characteristics of small chondrules to constrain the temperature history during the chondrule formation process.

Goswami, J. N.↗
NASA NTRS1985

A New NASTRAN Capability for Data Reduction

A new module, MODB, for the data reduction of NASTRAN results is described. NASTRAN analysis results can be filtered and sorted for minimum/maximum values and the printed output resulting from large NASTRAN runs can be limited based on a number of available user options. The sorting is done on stresses, forces and vector quantities like displacements, velocity, and acceleration. The module can be accessed via DMAP alters to existing rigid formats, and has been used on a large number of statics and dynamics problems resulting in considerable savings in cost, time, and the amount of printing.

Gallo, M.↗
NASA NTRS1985

The primary cosmic ray mass composition at energies above 10(14) eV

It is shown in this paper that the experimental data on extensive air showers at the energy interval 10 to the 15th power - 10 to the 17th power eV seems to be described best if it is assumed that the Galactic cosmic rays are described by some sort of a two component picture. The first component is of a mixed composition similar to that at lower energies and the second is dominated by protons. Overall spectrum starts to be enriched in protons at energies about 10 to the 15th power eV bu the effective mass of the primaries remains constant up to energies around 10 to the 16th power eV. That results from the fact that composition gradually changes from multi-component to mixture of protons and heavies. That picture receives also some sort of support from recent observations of relatively high number of nergetic protons in JACEE and Concorde experiments.

Gawin, J.↗
NASA NTRS1984

Size-distributions of chondrule types in the Inman and Allan Hills A77011 L3 chondrites

The size distributions of barred-olivine (BO) and radial-pyroxene/cryptocrystalline (RPC) chondrules are investigated in a petrographic study of nine and 18 thin sections (respectively) of the L3 chondrites Inman and ALHA77011. It is found that the Inman chondrules are significantly larger than the ALHA77011 chondrules and that RPC chondrules in Inman and BO chondrules in ALHA77011 are relatively more numerous, but no significant difference in the BO and RPC size distributions is observed. A formation mechanism involving size sorting of dustball chondrule precursors by aerodynamic particle-gas interactions in a large region of the solar nebula, melting of sorted dustballs in relatively small regions, and chondrule mixing and agglomeration (from subreservoirs containing uniformly large or uniformly small chondrules of a particular compositional type) to form chondrites is proposed.

Rubin, A. E.↗
NASA NTRS1987

Shuttle ground operations efficiencies/technologies study. Volume 4: Preliminary Issues Database (PIDB) catalog

The Preliminary Issues Database (PIDB) was assembled very early in the study as one of the fundamental tools to be used throughout the study. Data was acquired from a variety of sources and compiled in such a way that the data could be easily sorted in accordance with a number of different analytical objectives. The system was computerized to significantly expedite sorting and make it more usable. The information contained in the PIDB is summarized and the reader is provided with the capability to manually find items of interest.

Scholz, A. L.↗
NASA NTRS1988

Run-time parallelization and scheduling of loops

The class of problems that can be effectively compiled by parallelizing compilers is discussed. This is accomplished with the doconsider construct which would allow these compilers to parallelize many problems in which substantial loop-level parallelism is available but cannot be detected by standard compile-time analysis. We describe and experimentally analyze mechanisms used to parallelize the work required for these types of loops. In each of these methods, a new loop structure is produced by modifying the loop to be parallelized. We also present the rules by which these loop transformations may be automated in order that they be included in language compilers. The main application area of the research involves problems in scientific computations and engineering. The workload used in our experiment includes a mixture of real problems as well as synthetically generated inputs. From our extensive tests on the Encore Multimax/320, we have reached the conclusion that for the types of workloads we have investigated, self-execution almost always performs better than pre-scheduling. Further, the improvement in performance that accrues as a result of global topological sorting of indices as opposed to the less expensive local sorting, is not very significant in the case of self-execution.

Saltz, Joel H.↗
NASA NTRS1990

Schedule-Report-Generator Computer Program

Schedule Report Generator provides simple method for generating periodic schedule reports. Enables engineering manager to monitor tasks assigned to staff members on weekly basis. Sorts three types of reports by use of one or more data fields as sorting keys. Schedule Organizer (SO) (COSMIC program MSC-21525), Schedule Tracker (ST) (COSMIC program MSC-21526), and Schedule Report Generator (SRG) computer programs manipulating data-base files in ways advantageous in scheduling. Written in PL/1 and DEC Command Language (DCL).

Collazo, Fernando F.↗
NASA NTRS1989

Binary space partitioning trees and their uses

Binary Space Partitioning (BSP) trees have some qualities that make them useful in solving many graphics related problems. The purpose is to describe what a BSP tree is, and how it can be used to solve the problem of hidden surface removal, and constructive solid geometry. The BSP tree is based on the idea that a plane acting as a divider subdivides space into two parts with one being on the positive side and the other on the negative. A polygonal solid is then represented as the volume defined by the collective interior half spaces of the solid's bounding surfaces. The nature of how the tree is organized lends itself well for sorting polygons relative to an arbitrary point in 3 space. The speed at which the tree can be traversed for depth sorting is fast enough to provide hidden surface removal at interactive speeds. The fact that a BSP tree actually represents a polygonal solid as a bounded volume also makes it quite useful in performing the boolean operations used in constructive solid geometry. Due to the nature of the BSP tree, polygons can be classified as they are subdivided. The ability to classify polygons as they are subdivided can enhance the simplicity of implementing constructive solid geometry.

Bell, Bradley N.↗
NASA NTRS1990

HI and FIR emission from S0 galaxies

A large body of work has accumulated in recent years which throws into disarray the traditional assumption that S0 systems are inert, non-starforming galaxies with uniform, old stellar populations. The copious 21-cm data have been recently reviewed and assessed by Wardle and Knapp (1986). This work showed that roughly a third of the several hundred observed S0's contain detectable amounts of neutral hydrogen (HI). More recently, Pogge and Eskridge (1987) have shown that a significant fraction of HI-rich systems also exhibit H alpha emission. Thronson et al. (1989) report detection of CO line emission from two thirds of the S0's in their sample. Both of these last papers, however, report on fairly small data sets (approx. 20 objects each). From co-added Infrared Astronomy Satellite (IRAS) data, Knapp et al. (1989) report that roughly two thirds of a sample of several hundred S0's are detected at 60 and 100 microns. Work by Bally and Thronson (1989) and Walsh et al. (1989) has shown that, while a large number of S0's follow a relation between radio continuum and far infrared radiation (FIR) emission similar to that found for spirals, significant numbers of both radio-bright, and FIR-bright S0's exist. Clearly, a large number of factors are involved in determining the state of the interstellar medium in S0 galaxies. The class is probably heterogeneous, suggesting that large data samples are required to sort out various sorts of objects. The 21 cm and FIR samples are the two largest currently available. It is therefore of interest to compare the two and see where this leads. The following results are already clear: HI and FIR flux data can be used to isolate strong candidates for systems which have gained their HI gas via accretion; a rough power-law relationship exists for galaxies which are undergoing relatively normal star-forming activity; a heterogeneous class of galaxies with strong FIR emission compared to their HI emission exists. Further work is required to determine the various physical processes responsible for this last class.

Eskridge, Paul B.↗
NASA NTRS1989

Reference models for thermospheric NO

Nitric oxide has been measured with an ultraviolet spectrometer on the polar-orbiting satellite Solar Mesosphere Explorer (SME) for the period January 1982 to August 1986. The nitric oxide database contains densities at all latitudes sorted into 5 degree bins and at altitudes between 100 and 140 km sorted into 3.3 km-bins. The largest densities occur at latitudes in the auroral zones where the density varies as a function of geomagnetic activity. Variations of a factor of 10 occur between times of intense activity and quiet times. At low latitudes, the nitric oxide density at 110 km varies from a mean value of 3 times 10(exp 7) molecules per cubic cm in January 1982 to a mean value of 4 times 10(exp 6) molecules per cubic cm during solar minimum conditions in 1986. In addition, the low-latitude nitric oxide density varies plus or minus 50 percent with a period of 27 days during times of high solar activity.

Barth, C. A.↗
NASA NTRS1990

Neural computation of arithmetic functions

An area of application of neural networks is considered. A neuron is modeled as a linear threshold gate, and the network architecture considered is the layered feedforward network. It is shown how common arithmetic functions such as multiplication and sorting can be efficiently computed in a shallow neural network. Some known results are improved by showing that the product of two n-bit numbers and sorting of n n-bit numbers can be computed by a polynomial-size neural network using only four and five unit delays, respectively. Moreover, the weights of each threshold element in the neural networks require O(log n)-bit (instead of n-bit) accuracy. These results can be extended to more complicated functions such as multiple products, division, rational functions, and approximation of analytic functions.

Siu, Kai-Yeung↗
NASA NTRS1989

Systolic array processing of the sequential decoding algorithm

A systolic array processing technique is applied to implementing the stack algorithm form of the sequential decoding algorithm. It is shown that sorting, a key function in the stack algorithm, can be efficiently realized by a special type of systolic arrays known as systolic priority queues. Compared to the stack-bucket algorithm, this approach is shown to have the advantages that the decoding always moves along the optimal path, that it has a fast and constant decoding speed and that its simple and regular hardware architecture is suitable for VLSI implementation. Three types of systolic priority queues are discussed: random access scheme, shift register scheme and ripple register scheme. The property of the entries stored in the systolic priority queue is also investigated. The results are applicable to many other basic sorting type problems.

Chang, C. Y.↗