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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 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Structural lineaments of Gaspe from ERTS imagery

A test study was conducted to assess the value of ERTS images for mapping geologic features of the Gaspe Peninsula, Quebec. The specific objectives of the study were: 1) to ascertain the best procedure to follow in order to obtain valuable geologic data as a result of interpretation; and 2) to indicate in which way these data could relate to mineral exploration. Of the four spectral bands of the Multispectral scanner, the band from 700 to 800 nanometers, which seems to possess the best informational content for geologic study, was selected for analysis. The original ERTS image at a scale of 1:3,700,000 was enlarged about 15 times and reproduced on film. Geologically meaningful lines, called structural lineaments, were outlined and classified according to five categories: morpho-lithologic boundaries, morpho-lithologic lineaments, fault traces, fracture zones and undefined lineaments. Comparison with the geologic map of Gaspe shows that morpho-lithologic boundaries correspond to contacts between regional stratigraphic units. Morpholithologic lineaments follow bedding trends, whereas fracture traces appear as sets of parallel lineaments, intersecting at high angles the previous category of lineaments. Fault traces mark more precisely the location of faults already mapped and spot the presence of presumable faults, not indicated on the geologic map.

Steffensen, R.↗
NASA NTRS1974

Ion and electron temperatures in the SUMMA mirror device by emission spectroscopy

Ion and electron temperatures, and ion drift were measured in a superconducting magnetic mirror apparatus by observing the Doppler-broadened charge-exchange component of the 667.8 and 587.6 nanometer He lines in He plasma, and the H sub alpha and H sub beta lines in H2 plasma. The second moment of the line profiles was used as the parameter for determining ion temperature. Corrections for magnetic splitting, fine structure, monochromator slit function, and variation in charge-exchange cross section with energy are included. Electron temperatures were measured by the line ratio method for the corona model, and correlations of ion and electron temperatures with plasma parameters are presented.

Patch, R. W.↗
NASA NTRS1974

Ground truth data for test sites (SL-3)

Field measurements performed simultaneously with Skylab overpasses in order to provide comparative calibration and performance evaluation measurements for the EREP sensors are presented. The solar radiation region from 400 to 1300 nanometers and the thermal radiation region from 8 to 14 micrometer region were investigated. The measurements of direct solar radiation were analyzed for atmospheric optical depth; the total and reflected solar radiation were analyzed for target reflectivity. These analyses were used in conjunction with a radiative transfer computer program in order to calculate the amount and spectral distribution of solar radiation at the apertures of the EREP sensors. The instrumentation and techniques employed, calibrations and analyses performed, and results obtained are discussed.

Source record↗
NASA NTRS1974

Ground truth data for test sites (SL-4)

Field measurements performed simultaneous with Skylab overpass in order to provide comparative calibration and performance evaluation measurements for the EREP sensors are presented. Wavelength region covered include: solar radiation (400 to 1300 nanometer), and thermal radiation (8 to 14 micrometer). Measurements consisted of general conditions and near surface meteorology, atmospheric temperature and humidity vs altitude, the thermal brightness temperature, total and diffuse solar radiation, direct solar radiation (subsequently analyzed for optical depth/transmittance), and target reflectivity/radiance. The particular instruments used are discussed along with analyses performed. Detailed instrument operation, calibrations, techniques, and errors are given.

Source record↗
NASA NTRS1974

Ice particulates in the mesosphere

The observations of noctilucent clouds, the measurements of hydrated and of large immobile ions, and the light-scattering layer detected by the OGO-6 satellite suggest the presence of particulates, probably ice, in the mesosphere. The correlation between temperature and positive ion conductivity where the vapor pressure over ice becomes greater than atmospheric pressure in the stratopause region indicates the presence of ice crystals throughout the mesosphere over a wide range of latitudes during all seasons. Between one and ten billion ice crystals per cubic meter of order 10 nanometers in diameter can dominate ionization loss processes in the mesosphere, and can explain a variety of experimental observations, including observed solar angle dependence and seasonal variability of electron density.

Chesworth, E. T.↗
NASA NTRS1976

Extreme ultraviolet survey experiment MA-083

A grazing incidence telescope sensitive to radiation in the 5- to 100-nanometer band was flown in the Apollo service module. On 10 nighttime revolutions, the command and service module was maneuvered to point the instrument at 30 different stellar targets for periods of 1 to 20 minutes, thus constituting the first sensitive search for extreme ultraviolet radiation from nonsolar sources. Several hours of supplementary data were also obtained during nighttime orbits when other experiments in the scientific instrument module bay were operating. Preliminary analysis of a small fraction of the total data indicates the definite detection of a strong source of extreme ultraviolet radiation during observations made during revolution 109. The source is located in Coma Berencies. The suggested optical identification is the white dwarf HZ 43. If this association is correct, the star has the highest temperature of any known white dwarf. Regardless of the optical identification, however, this object is the first nonsolar source to be detected in the extreme ultraviolet band.

Bowyer, S.↗
NASA NTRS1977

Effect of ion-plated films of germanium and silicon on friction, wear, and oxidation of 52100 bearing steel

Friction and wear experiments were conducted with ion plated films of germanium and silicon on the surface of 52100 bearing steel both dry and in the presence of mineral oil. Both silicon and germanium were found to reduce wear, with germanium being more effective than silicon. An optimum film thickness of germanium for minimum wear without surface crack formation was found to be approximately 400 nanometers (4000 A). The presence of silicon and germanium on the 52100 bearing steel surface improved resistance to oxidation.

Buckley, D. H.↗
NASA NTRS1977

Shock tube measurements of the optical absorption of triatomic carbon, C3

The spectral absorption of C3 has been measured in a shock tube using a test gas mixture of acetylene diluted with argon. The absorption of a pulsed xenon light source was measured by means of eight photomultiplier channels to a spectrograph and an accompanying drum camera. The postshock test gas temperature and pressure were varied over the range 3300-4300 K and 0.36 to 2.13 atmospheres, respectively. The results showed appreciable absorption from C3 for the wavelength range 300 to 540 nanometers. The computed electronic oscillator strength varied from 0.12 to 0.06 as a function of temperature.

Jones, J. J.↗
NASA NTRS1977

Atmospheric lidar research applying to H2O, O2 and aerosols

Experimental research on a near infrared tunable dye laser was reported, and theoretical simulations were presented for various lidar configurations. The visible and nearinfrared wavelengths considered were suitable for observations of aerosols, water vapor, molecular oxygen pressure and temperature in the troposphere and above. The first phase of development work was described on a ruby pumped, tunable dye laser for the wavelength region 715 to 740 nanometers. Lidar simulations were summarized for measurements of H2O and for two color lidar observations of aerosols in the atmosphere.

Mcilrath, T. J.↗
NASA NTRS1977

Effects of detector threshold, location of the sun, and flight altitude upon spectral variations in remote sensing over water

Photographic flights with Hasselblad cameras were flown on August 28, 1975, at altitudes from 2.66 and 5.3 kilometers over an ocean acid waste dump site while acid dumping was in progress. Repeated flights resulted in broadband spectral radiance data between the wavelengths of 500 to 900 nanometers for sun elevation angles that varied from 26 to 48 degrees, and at all sun azimuth angles over the range of off-nadir angles from 0 to 35 degrees. From film densitometer data, it is shown that before spectral variations in remotely sensed data can be used to quantify substances in water, the longer wavelength data must be above the detection level of the detector, radiance data between + or - 45 degrees in the direction of the sun must be avoided, and off-nadir camera correction factors must be applied to the observed radiance data.

Bressette, W. E.↗
NASA NTRS1978

Effect of sun elevation upon remote sensing of ocean color over an acid waste dump site

Photographic flights were made over an ocean acid waste dump site while dumping was in progress. The flights resulted in wide angle, broadband, spectral radiance film exposure data between the wavelengths of 500 to 900 nanometers for sun elevation angles ranging from 26 to 42 degrees. It is shown from densitometer data that the spectral signature of acid waste discharged into ocean water can be observed photographically, the influence of sun elevation upon remotely sensed apparent color can be normalized by using a single spectral band ratioing technique, and photographic quantification and mapping of acid waste through its suspended iron precipitate appears possible.

Bressette, W. E.↗
NASA NTRS1979

Aerial photographic water color variations from the James River

Photographic flights from 305 meters altitude were made throughout the day of May 17, 1977, over seven water data stations in the James River. The flights resulted in wide-angle, broadband, spectral radiance film exposure data between the wavelengths of 500 to 900 nanometers for sun elevation angles ranging from 37 to 64 deg and variable atmospheric haze conditions. It is shown from densitometer data that: (1) the dominant observed color from James River waters is determined by the optical properties of the total suspended solid load, (2) variability in observed color is produced by a changing solar elevation angle; and (3) the rate at which observed color changes is influenced by both solar elevation angle and atmospheric conditions.

Bressette, W. E.↗
NASA NTRS1979

Further results of the Pioneer Venus nephelometer experiment

Backscattering data for the nephelometer experiments conducted aboard the Pioneer Venus mission probes, including data up to the highest altitudes measured by the probes, are presented. A few small signals were detected below the main cloud deck. Ambient radiation was measured at near-ultraviolet and visible wavelengths; the variation of extinction of near-ultraviolet with altitude is inferred. Ambient radiance decreased more rapidly at 530 than at 745 nanometers in the lower atmosphere.

Blamont, J.↗
NASA NTRS1983

Clear Film Protects Against Ultraviolet Radiation

Acrylic film contains screeing agent filtering ultraviolet radiation up to 380 nanometers in wavelength but passes other components of Sunlight. Film used to protect such materials as rubber and plastics degraded by ultraviolet light. Used as protective cover on outdoor sheets or pipes made of such materials as polyethylene or polypropylene and on solar cells.

Gupta, A.↗
NASA NTRS1981

Soft X-ray imaging with a normal incidence mirror

By sputtering, it is possible to make multilayered structures (layered synthetic microstructures or LSMs) with individual layers as thin as a fraction of a nanometer. These techniques have been used to make a multilayered interference mirror to reflect carbon K X rays (at a wavelength of 4.48 nm) at normal incidence. The structure consists of 76 layers of tungsten of thickness 0.765 nm with layers of carbon (thickness 1.510 nm) interspersed, deposited on a 111 line type silicon wafer substrate. This LSM was formed into a concave mirror of radius approximately 1.1 m by bending the substrate, and used in an optical set-up to form images of grids illuminated by an X-ray source. The mirror was found to have a resolution of 5 lines/mm and an efficiency, integrated over the CK band, of between 4 and 8%.

Underwood, J. H.↗
NASA NTRS1982

Imaging spectrometer technologies for advanced Earth remote sensing

A major requirement of multispectral imaging systems for advanced Earth remote sensing is the provision for greater spectral resolution and more versatile spectral band selection. The imaging spectrometer instrument concept provides this versatility by the combination of pushbroom imaging and spectrally dispersing optics using area array detectors in the focal plane. The shuttle imaging spectrometer concept achieves 10- and 20-meter ground instantaneous fields of view with 20-nanometer spectral resolution from Earth Orbit. Onboard processing allows the selection of spectral bands during flight; this, in turn, permits the sensor parameters to be tailored to the experiment objectives. Advances in optical design, infrared detector arrays, and focal plane cooling indicate the feasibility of the instrument concept and support the practicability of a validation flight experiment for the shuttle in the late 1980s.

Wellman, J. B.↗
NASA NTRS1982

A Hand Held Ratioing Radiometer for remote radiance measurements

The small, lightweight Hand Held Ratioing Radiometer (HHRR) measures the ratio of spectral reflectance in any of 25 pairs of narrow bands in the 400 to 2500 nanometer spectral region. Two parallel optical trains view the scene through separate filters mounted in two filter wheels each containing five filters. Absolute reflectance of the scene can also be measured. HHRR is particularly useful for ground truth studies for the interpretation of imagery from Landsat, the thematic mappers and the forthcoming SPOT satellite. Its small size and simplicity of operation make it useful to geologists, botanists, oceanographers and many other geotechnologists.

Daubner, L.↗
NASA NTRS1984

Mechanical contact induced transformation from the amorphous to the crystalline state in metallic glass

Friction and wear tests were conducted with 3.2- and 6.4-millimeter-diameter aluminum oxide spheres sliding, in reciprocating motion, on a Fe67Co18B14Si1 metallic foil. Crystallites with a size range of 10 to 150 nanometers were produced on the wear surface of the amorphous alloy. A strong interaction between transition metals and metalloids such as silicon and boron results in strong segregation during repeated sliding, provides preferential transition metal-metalloid clustering in the amorphous alloy, and subsequently produces the diffused honeycomb structure formed by dark grey bands and primary crystals, that is, alpha-Fe in the matrix. Large plastic flow occurs on an amorphous alloy surface with sliding and the flow film of the alloy transfers to the aluminum oxide pin surface. Multiple slip bands due to shear deformation are observed on the side of the wear track. Two distinct types of wear debris were observed as a result of sliding: an alloy wear debris, and/or powdery-whiskery oxide debris.

Miyoshi, K.↗