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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 1,315 records · Page 73
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Investigation of environmental change pattern in Japan: A study on change detection of land cover in Tokyo districts using multi-dates LANDSAT CCT

The author has identified the following significant results. The software program, which enables the geographically corrected LANDSAT digital data base, was developed. The data base could provide land use planners with land cover information and the environmental change pattern. Land cover was evaluated by the color representation for ratio of three primary components, water vegetation, and nonorganic matter. Software was also developed for the change detection within multidates LANDSAT MSS data.

Maruyasu, T.↗
NASA NTRS1976

Experiment to Evaluate the Feasibility of Utilizing Skylab-EREP Remote Sensing Data for Tectonic Analysis Through a Study of the Big Horn Mountain Region, Wyoming, South Dakota and Wyoming

The author has identified the following significant results. S190B imagery was the best single product from which fairly detailed structural and some lithologic mapping could be accomplished in the Big Horn basin, the Owl Creek Mountains, and the northern Big Horn Mountains. The Nye-Bowler lineament could not be extended east of its presently mapped location although a linear (fault or monocline) was noted that may be part of the lineament, but north of postulated extensions. Much more structure was discernible in the Big Horn basin than could be seen on LANDSAT-1 imagery; RB-57 color IR photography, in turn, revealed additional folds and faults. A number of linears, several of which could be identified as faults and one a monocline, cut obliquely the east-west trending Owl Creek uplift. The heavy forest cover of the Black Hills makes direct lithologic delineation impossible. However, drainage and linear overlays revealed differences in pattern between the areas of exposed Precambrian crystalline core and the flanking Paleozoic rocks. S192 data, even precision corrected segments, were not of much use.

Hoppin, R. A.↗
NASA NTRS1976

Report on the lunar ranging at McDonald Observatory, 1 February - 31 May 1976

The four spring lunations produced 105 acquisitions, including the 2000th range measurement made at McDonald Observatory. Statistics were normal for the spring months. Laser and electronics problems are noted. The Loran-C station delay was corrected. Preliminary doubles data is shown. New magnetic tape data formats are presented. R and D efforts include a new laser modification design.

Palm, C. S.↗
NASA NTRS1975

Performance of and planned improvements to a mountain altitude cosmic ray mass spectrometer

A cosmic ray mass spectrometer with superconducting magnet, wire spark chambers, and time-of-flight scintillation counters has been operated at an altitude of 2750 meters. Various specifications of the spectrometer are presented and the method of event analysis described. Corrections to the data, resolutions and efficiencies of the spark chambers, and momentum resolution are discussed. Recent and planned improvements of the apparatus are indicated.

Jones, J. J.↗
NASA NTRS1977

The panel on propulsion aerodynamics

Sources of discrepancies noted between propulsion aerodynamic characteristics as predicted from wind tunnel tests and as measured in flight are discussed. The variable Reynolds capability of the National Transonic Facility will provide a tool for understanding and quantifying uncertainties involved in extrapolating the corrected wind tunnel data from tunnel conditions to full scale flight conditions.

Bowditch, D.↗
NASA NTRS1976

Effects of horizontal refractivity gradients on the accuracy of laser ranging to satellites

Numerous formulas have been developed to partially correct laser ranging data for the effects of atmospheric refraction. All the formulas assume the atmospheric refractivity profile is spherically symmetric. The effects of horizontal refractivity gradients are investigated by ray tracing through spherically symmetric and three-dimensional refractivity profiles. The profiles are constructed from radiosonde data. The results indicate that the horizontal gradients introduce an rms error of approximately 3 cm when the satellite is near 10 deg elevation. The error decreases to a few millimeters near zenith.

Gardner, C. S.↗
NASA NTRS1976

ISIS-2 satellite imagery and auroral morphology

Auroral morphology is emphasized over auroral dynamics in a paper describing conspicuous auroral features picked up by the ISIS-2 scanning photometer. Results of improved programs designed to transform the data into a corrected geomagnetic coordinate frame and generate latitude profiles of auroral intensities at different magnetic local times are reported. The diffuse aurora and its relation to the morphology of discrete aurorae is given special attention.

Anger, C. D.↗
NASA NTRS1977

A catalog of 0.2 A resolution far-ultraviolet stellar spectra measured with Copernicus

Spectra between 1000 and 1450 A for 60 O- and B-type stars observed by Copernicus at 0.2-A resolution are presented in three forms: tables containing the numerical data, plots showing renormalized spectra, and synthetic photographic spectra. The data have been corrected for all instrument effects of importance for the photometric accuracy except fluctuations in continuum level caused by small variations in spacecraft guidance. Spectrometer sensitivity curves are provided for use in converting to absolute fluxes. It is expected that this catalog will be of use for research on many aspects of stellar UV spectra, including spectral classification, line identification, abundance determinations, spectrum synthesis, model atmosphere calculations, flux distributions, bolometric corrections, stellar winds, and mass loss.

Snow, T. P., Jr.↗
NASA NTRS1977

The sun-tracking control of solar collectors using high-performance step motors

Sun-tracking solar energy-focusing devices involving a central receiver, thermionic conversion, or a distributed solar thermal collector system are described. The Perkins solar collector uses a fixed focal point about which an 18 m-diameter parabolic dish moves on tracks. The elevation axis also moves on a circular track. A microprocessor manipulates sun sensor information and sun ephemeris data to ensure correct placement. Stepper motors are digital devices which provide direct interface with digital electronics and a wide dynamic range, and could easily be associated with the microprocessors. Design philosophy, performance criteria, wind load analysis, and control system requirements are also discussed.

Hughes, R. O.↗
NASA NTRS1977

Significance of vegetation in interpreting thermal radiation from a terrestrial surface

The regions between crop rows are modeled as infinitely long diffuse cavities. Geometrical view factors are calculated, accounting for reflected radiation emanating internal to the cavity and from the background sky. A 'cavity' emissivity dependent on local geometry is defined to allow for correcting apparent temperatures to true temperatures. The total emissivity appropriate for correcting aircraft thermal data is then calculated by averaging all emissivity components to account for soil, crop, and background. It is shown that even for the lowest crop and vegetation emissivities, if the crop height-to-spacing ratio is greater than unity, the composite emissivity is greatly increased, giving rise to a decreased error in remotely sensed temperature data.

Sutherland, R. A.↗
NASA NTRS1977

Effect of forward motion on engine noise

Methods used to determine a procedure for correcting static engine data for the effects of forward motion are described. Data were analyzed from airplane flyover and static-engine tests with a JT8D-109 low-bypass-ratio turbofan engine installed on a DC-9-30, with a CF6-6D high-bypass-ratio turbofan engine installed on a DC-10-10, and with a JT9D-59A high-bypass-ratio turbofan engine installed on a DC-10-40. The observed differences between the static and the flyover data bases are discussed in terms of noise generation, convective amplification, atmospheric propagation, and engine installation. The results indicate that each noise source must be adjusted separately for forward-motion and installation effects and then projected to flight conditions as a function of source-path angle, directivity angle, and acoustic range relative to the microphones on the ground.

Blankenship, G. L.↗
NASA NTRS1977

Bolivian satellite technology program on ERTS natural resources

The author has identified the following significant results. Application of digital classification for mapping land use permitted the separation of units at more specific levels in less time. A correct classification of data in the computer has a positive effect on the accuracy of the final products. Land use unit comparison with types of soils as represented by the colors of the coded map showed a class relation. Soil types in relation to land cover and land use demonstrated that vegetation was a positive factor in soils classification. Groupings of image resolution elements (pixels) permit studies of land use at different levels, thereby forming parameters for the classification of soils.

Brockmann, H. C.↗
NASA NTRS1979

Flight Mechanics/Estimation Theory Symposium

Onboard and real time image processing to enhance geometric correction of the data is discussed with application to autonomous navigation and attitude and orbit determination. Specific topics covered include: (1) LANDSAT landmark data; (2) star sensing and pattern recognition; (3) filtering algorithms for Global Positioning System; and (4) determining orbital elements for geostationary satellites.

Fuchs, A. J.↗
NASA NTRS1979

Functional definition and design of a USDA system

The fundamental definition and design of a U.S.D.A. system utilizing the LACIE technology avaliable as of June 1976, is discussed. The organization and methods described are focused on LACIE technology in terms of its transfer for use applications. The simulation of a feasible system design provided timely answers to system design questions, such as the ability of a minicomputer to handle the proposed geometrical correction of MSS data.

Evans, S. M.↗
NASA NTRS1980

Recent research on V/STOL test limits at the University of Washington aeronautical laboratory

The occurence of flow breakdown during the wind tunnel testing of a powered V/STOL aircraft was studied. Flow breakdown is the low forward speed test limit in a solid wall wind tunnel and is characterized by a vortex which forms on the floor and walls of the wind tunnel thereby failing to simulate free air conditions. The flow is caused by the interaction of the model wake and tunnel boundary layer and affects the model's aerodynamic characteristics in such fashion as to negate their reliability as correctable wind tunnel data. The low speed test limit was examined using a model that possessed a discretely concentrated powered lift system using a pair of lift jets. The system design is discussed and the tests and results which show that flow breakdown occurs at a velocity ratio of approximately 0.20 are reported.

Shindo, S.↗
NASA NTRS1980

LAPR: An experimental aircraft pushbroom scanner

A three band Linear Array Pushbroom Radiometer (LAPR) was built and flown on an experimental basis by NASA at the Goddard Space Flight Center. The functional characteristics of the instrument and the methods used to preprocess the data, including radiometric correction, are described. The radiometric sensitivity of the instrument was tested and compared to that of the Thematic Mapper and the Multispectral Scanner. The radiometric correction procedure was evaluated quantitatively, using laboratory testing, and qualitatively, via visual examination of the LAPR test flight imagery. Although effective radiometric correction could not yet be demonstrated via laboratory testing, radiometric distortion did not preclude the visual interpretation or parallel piped classification of the test imagery.

Wharton, S. W.↗
NASA NTRS1980

Thermal Pollution Mathematical Model. Volume 5: User's Manual for Three-Dimensional Rigid-Lid Model

A user's manual for a three dimensional, rigid lid model used for hydrothermal predictions of closed basins subjected to a heated discharge together with various other inflows and outflows is presented. The model has the capability to predict (1) wind driven circulation; (2) the circulation caused by inflows and outflows to the domain; and (3) the thermal effects in the domain, and to combine the above processes. The calibration procedure consists of comparing ground truth corrected airborne radiometer data with surface isotherms predicted by the model. The model was verified for accuracy at various sites and results are found to be fairly accurate in all verification runs.

Lee, S. S.↗