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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 1,333 records · Page 74
All sourcesNASA NTRSDOE OSTI
NASA NTRS1981

Tropical cyclone intensity change. A quantitative forecasting scheme

One to two day future tropical cyclone intensity change from both a composite and an individual case point-of-view are discussed. Tropical cyclones occurring in the Gulf of Mexico during the period 1957-1977 form the primary data source. Weather charts of the NW Atlantic were initially examined, but few differences were found between intensifying and non-intensifying cyclones. A rawinsonde composite analysis detected composite differences in the 200 mb height fields, the 850 mb temperature fields, the 200 mb zonal wind and the vertical shears of the zonal wind. The individual cyclones which make up the composite study were then separately examined using this composite case knowledge. Similar parameter differences were found in a majority of individual cases. A cyclone intensity change forecast scheme was tested against independent storm cases. Correct predictions of intensification or non-intensification could be made approximately 75% of the time.

Dropco, K. M.↗
NASA NTRS1982

Space Shuttle preliminary. Contamination assessment from STS-1 and STS-2

A preliminary assessment of the space shuttle contamination environment was made using data from the first two orbital flight tests, STS-1 and STS-2. Data sources consisted of crew observations during flight, postflight vehicle inspection, and the induced environment contamination monitor which was used on STS-2 and consists of 10 instruments. These instruments are used to measure gas phase contaminants, particle population, humidity, and molecular deposition in the orbiter payload bay during ascent and descent and particle population, molecular deposition, and gas cloud during orbital flight. Results of the measurements described are presented in summary form and indicate low molecular deposition rates for both pressurized and orbital flight.

Leger, L. J.↗
NASA NTRS1982

Thermal stability of the surface layer and its relation to the dispersion of primary pollutants in St. Louis

The present investigation is concerned with the applicability of the vertical temperature gradient, DT, as a dispersion parameter for urban area sources. Data on DT were tabulated from temperature measurements at 5 m and 30 m obtained on 30 m towers at 12 stations. DT was obtained by subtracting the value at 5 m from that at 30 m. Positive DT values represent an inversion. Accuracy of the DT data is 0.1 K. Hourly measurements of DT along with concentrations of the primary pollutants, CO, NO, and total hydrocarbons (THC), are available from the 1976 RAPS data base for St. Louis. Linear correlations between a given pollutant species concentration and DT are developed from that data set. It could be confirmed that a strong positive correlation exists at night between the thermal stability of the lowest part of the boundary layer and the urban concentration of the primary pollutants CO, NO, and hydrocarbons.

Remsberg, E. E.↗
NASA NTRS1982

Detecting residential land-use development at the urban fringe

Problems associated with the use of Landsat multispectral scanner (MSS) imagery for the detection of urban growth and land use patterns are discussed. The presence of vegetation, either original or added between scanning periods, has been found to dramatically effect the range of signatures in a given area. Different land use developmental stages have been successfully identified by means of 1:50,000 scale panchromatic aerial photography, a resolution only considered possible by spaceborne instrumentation with the advent of the Landsat D satellite. Textural information generated through the grey-tone spatial-dependency matrix for the Landsat band 5 data is compared for different years and a change detection algorithm is described. It is found that the addition of vegetation during development after the removal of natural vegetation resulted in error of omission in the single band data, which must therefore only be used in concert with other data sources.

Jensen, J. R.↗
NASA NTRS1982

Shuttle orbiter stellar-inertial reference system

The Space Shuttle stellar-inertial reference system is a velocity and attitude data source during flight operations. An overview of the reference system is presented as well as specifics discussing design concepts, functional operation, and performance capabilities. Techniques for star sighting and inertial measurement unit alignment and calibration are described, and alignment accuracy, star tracker capability, and gyro and accelerometer accuracy are discussed, with emphasis on flight test results. Test programs have confirmed that the system meets performance requirements such as being accurate to within 0.26 degree at the 400,000 foot altitude entry interface in order to execute an accurate touchdown, as well as demonstrating reusability, payload capability, and operational flexibility. Growth possibilities, such as the implementation of rendezvous target tracking, are discussed.

Smith, F. E.↗
NASA NTRS1981

Software for universal noiseless coding

An overview is provided of the universal noiseless coding algorithms as well as their relationship to the now available FORTRAN implementations. It is suggested that readers considering investigating the utility of these algorithms for actual applications should consult both NASA's Computer Software Management and Information Center (COSMIC) and descriptions of coding techniques provided by Rice (1979). Examples of applying these techniques have also been given by Rice (1975, 1979, 1980). Attention is given to reversible preprocessing, general implementation instructions, naming conventions, and calling arguments. A general applicability of the considered algorithms to solving practical problems is obtained because most real data sources can be simply transformed into the required form by appropriate preprocessing.

Rice, R. F.↗
NASA NTRS1982

Evaluation of the user requirements processes for NASA terrestrial applications programs

To support the evolution of increasingly sound user requirements definition processes that would meet the broad range of NASA's terrestrial applications planning and management needs during the 1980's, the user requirements processes as they function in the real world at the senior and middle management levels were evaluated. Special attention was given to geologic mapping and domestic crop reporting to provide insight into problems associated with the development and management of user established conventional practices and data sources. An attempt was made to identify alternative NASA user interfaces that sustain strengths, alleviate weaknesses, maximize application to multiple problems, and simplify management cognizance. Some of the alternatives are outlined and evaluated. It is recommended that NASA have an identified organizational point of focus for consolidation and oversight of the user processes.

Source record↗
NASA NTRS1983

Study of LANDSAT-D thematic mapper performance as applied to hydrocarbon exploration

Analysis of the tapes of the Detroit, Michigan scene, which were received in fully processed format with geometric and radiometric correction, shows evidence of an along line data slip every sixteenth line in TM channel 2. Very large scale products were therefore generated in false color using channels 1, 3, and 4. Subjective evaluation of these enhanced scenes indicates that they are acceptable for interpretation at scales up to 1:50,000 and should be useful for change mapping probably up to 1:24,000 scale. The significant striping visible in water bodies for both the natural color and false color products indicates that the detector calibration is probably performing below the preflight specification. Variance-covariance matrices were computed and principal component analysis were performed for a set of 512 x 512 windows within the Arkansas scene. Initial analysis shows the shortwave infrared channels (TM 5 and 6) are a highly significant data source. The thermal channel (TM 7) shows negative correlation with TM 1 through 4.

Source record↗
NASA NTRS1983

Study of LANDSAT-D thematic mapper performance as applied to hydrocarbon exploration

Two fully processed test tapes were enhanced and evaluated at scales up to 1:10,000, using both hardcopy output and interactive screen display. A large scale, the Detroit, Michigan scene shows evidence of an along line data slip every sixteenth line in TM channel 2. Very large scale products generated in false color using channels 1,3, and 4 should be very acceptable for interpretation at scales up to 1:50,000 and useful for change mapping probably up to scale 1:24,000. Striping visible in water bodies for both natural and color products indicates that the detector calibration is probably performing below preflight specification. For a set of 512 x 512 windows within the NE Arkansas scene, the variance-covariance matrices were computed and principal component analyses performed. Initial analysis suggests that the shortwave infrared TM 5 and 6 channels are a highly significant data source. The thermal channel (TM 7) shows negative correlation with TM 1 and 4.

Everett, J. R.↗
NASA NTRS1983

High-accuracy global time and frequency transfer with a space-borne hydrogen maser clock

A proposed system for high-accuracy global time and frequency transfer using a hydrogen maser clock in a space vehicle is discussed. Direct frequency transfer with a accuracy of 10 to the minus 14th power and time transfer with an estimated accuracy of 1 nsec are provided by a 3-link microwave system. A short pulse laser system is included for subnanosecond time transfer and system calibration. The results of studies including operational aspects, error sources, data flow, system configuration, and implementation requirements for an initial demonstration experiment using the Space Shuttle are discussed.

Decher, R.↗
NASA NTRS1984

The G-002 JUFO-1 payload: Its objectives and results

The JUFO-1 payload basically consists of the mechanical support structure with two shock isolated mounting shelves for the experiment hardware and the service systems. For the envisaged operation time of 72 hours, three 28 VDC batteries, with a total capacity of approx 1,7 kWh are chosen as a partially redundant power source. Data are acquired by a 12 bit PCM system and stored on a tape recorder. Five experiments were conducted: (1) growth of a liquid KH2PO4 salt solution; (2) manufacturing of nickel catalysts; (3) transport mechanisms of heavy metals in water cress shoots; (4) determining the influence of cosmic radiation on four different plant seeds; and (5) use of a microprocessor-sequencer for payload control and sequencing at a low power consumption.

Schmitt, G.↗
NASA NTRS1983

A study of space station needs, attributes and architectural options. Volume 2: Technical. Book 1: Mission requirements. Appendixes 1 and 2

The space station mission requirements data base consists of 149 attached and free-flying missions each of which is documented by a set of three interrelated documents: (1) NASA LaRC Data Sheets - with three sheets comprising a set for each payload element described. These sheets contain user payload element data necessary to drive Space Station architectural options. (2) GDC-derived operations descriptions that supplement the LaRC payload element data in the operations areas such as further descriptions of crew involvement, EVA, etc. (3) Payload elements synthesis sheets used by GDC to provide requirements traceability to data sources and to provide a narrative describing the basis for formulating the payload element requirements.

Source record↗
NASA NTRS1984

Statistical severe storm nowcasting comparison of VAS and Rawinsonde soundings

The statistical severe storm nowcasting technique using upper air soundings (VAS or radiosonde) is translated to the IBM McIDAS system. The severe storm information content of Visible infrared spin scan radiometer Atmospheric Sounder (VAS) and rawinsonde sounding data is compared. The contours of the likelihood of severe storms based only upon upper air VAS and rawinsonde data are shown, as well as the outlook based upon surface data, radar, operational computer models, and other data sources.

Keller, D. L.↗
NASA NTRS1982

Information processing of earth resources data

Current trends in the use of remotely sensed data include integration of multiple data sources of various formats and use of complex models. These trends have placed a strain on information processing systems because an enormous number of capabilities are needed to perform a single application. A solution to this problem is to create a general set of capabilities which can perform a wide variety of applications. General capabilities for the Image-Based Information System (IBIS) are outlined in this report. They are then cross-referenced for a set of applications performed at JPL.

Zobrist, A. L.↗
NASA NTRS1986

Universal Noiseless Coding Subroutines

Software package consists of FORTRAN subroutines that perform universal noiseless coding and decoding of integer and binary data strings. Purpose of this type of coding to achieve data compression in sense that coded data represents original data perfectly (noiselessly) while taking fewer bits to do so. Routines universal because they apply to virtually any "real-world" data source.

Schlutsmeyer, A. P.↗
NASA NTRS1985

Assessment of VAS soundings in the analysis of a preconvective environment

Retrievals from the VISSR Atmospheric Sounder (VAS) are combined with conventional data to assess the impact of geosynchronous satellite soundings upon the analysis of a preconvective environment. VAS retrievals of temperature, dewpoint, equivalent potential temperature, precipitable water, and lifted index are derived with 60 km resolution at 3 hour intervals. When VAS fields are combined with analyses from conventional data sources, mesoscale regions with convective instability are more clearly delineated prior to the rapid development of the thunderstorms. The retrievals differentiate isolated areas in which air extends throughout the lower troposphere from those regions where moisture is confined to a thin layer near the Earth's surface. The analyses of the VAS retrievals identify significant spatial gradients and temporal changes in the thermal and moisture fields, especially in the regions between radiosonde observations.

Mostek, A.↗
NASA NTRS1985

Derivation of Model Topography

The Fourth-Order model necessitates representation of the topography. The problem of the representation of the topography at grid points is addressed. The attempted was to derive an envelope topography. The TI is obtained by taking local mean plus one standard deviation at each grid point and sigma filtering it. The method was greatly influenced by large standard deviations at steep mountains. The O1 topography is the local mean. The S1 is obtained by Sigma filtering in both latitude and longitude the mean O1. The S2 is when the operation is applied twice and S3 thrice, the Q3 is the sigma filtered local mean of the upper third quantile of the source data.

Balgovind, R. C.↗
NASA NTRS1985

A new array for the study of ultra high energy gamma-ray sources

The design and operation of a 32 x 1 10 to the 15th power sq m array of scintillation detectors for the detection of 10 to the 15th power eV cosmic rays is described with an expected angular resolution of 1 deg, thus improving the present signal/background ratio for gamma ray sources. Data are recorded on a hybrid CAMAC, an in-house system which uses a laser and Pockel-Cell arrangement to routinely calibrate the timing stability of the detectors.

Brooke, G.↗