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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 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Heavy ion passive dosimetry with silver halide single crystals

A method of detecting radiation damage tracks due to heavy particles in large single crystals of the silver halides is described. The tracks, when made visible with a simple electrical apparatus, appear similar to tracks in emulsions. The properties of the crystals, the technique of printing out the tracks, and evidence concerning the threshold energy for registering particles indicates that this method may find application in heavy ion dosimetry. The method has been found to be sensitive to stopping He nuclei and relativistic M group cosmic rays. Some impurities strongly influence the printout of the tracks, and the effects of these impurities are discussed.

Childs, C. B.↗
NASA NTRS1971

Correlation of spray dropsize distribution and injector variables

The atomization characteristics of impinging stream rocket engine injection elements are studied to determine the effects of hydraulic and geometric parameters on the mass median drop size. The major conclusions are: (1) the velocity profile of impinging jets affects mean drop size, this effect is greater when the jets are laminar than when they are turbulent; (2) the drop size/injection velocity dependence for turbulent jet impingement differs from that obtained with non-turbulent jets; (3) the level of turbulence intensity does not affect mean drop size; (4) the impingement of disintegrated or nearly disintegrated jets substantially decreases atomization; and (5) even though an emulsion is formed when immiscible jets impinge, the level of emulsification is small.

Zajac, L. J.↗
NASA NTRS1972

Mapping of terrain by computer clustering techniques using multispectral scanner data and using color aerial film

Two clustering techniques were used for terrain mapping by computer of test sites in Yellowstone National Park. One test was made with multispectral scanner data using a composite technique which consists of (1) a strictly sequential statistical clustering which is a sequential variance analysis, and (2) a generalized K-means clustering. In this composite technique, the output of (1) is a first approximation of the cluster centers. This is the input to (2) which consists of steps to improve the determination of cluster centers by iterative procedures. Another test was made using the three emulsion layers of color-infrared aerial film as a three-band spectrometer. Relative film densities were analyzed using a simple clustering technique in three-color space. Important advantages of the clustering technique over conventional supervised computer programs are (1) human intervention, preparation time, and manipulation of data are reduced, (2) the computer map, gives unbiased indication of where best to select the reference ground control data, (3) use of easy to obtain inexpensive film, and (4) the geometric distortions can be easily rectified by simple standard photogrammetric techniques.

Smedes, H. W.↗
NASA NTRS1972

Coastal and estuarine applications of multispectral photography

An evaluation of multispectral photographic techniques for optical penetration of water in the northeastern United States and the Gulf of Mexico coastal waters is presented. The spectral band (493 to 543 nanom), when exposed to place the water mass at about unit density on the photographic emulsion, was found to provide the best water penetration, independent of altitude or time of day, as long as solar glitter from the surface of the water is avoided. An isoluminous color technique was perfected, which eliminates the dimension of brightness from a multispectral color presentation.

Yost, E.↗
NASA NTRS1972

The use of Kodak aerochrome infrared color film, type 2443, as a remote sensing tool

An infrared color film, Kodak Aerochrome, type 2443, has replaced the 8443 film. The 2443 has lower contrast than the 8443 film, and allows deeper probing into areas that appear as solid black shadows on the 8443 film. The cyan layer of 2443 is approximately 1 1/2 stops slower, at a density of 1.4, than the yellow and magenta emulsion layers.

Cooper, G. R.↗
NASA NTRS1972

A general purpose wideband optical spatial frequency spectrum analyzer

The light scattered at various angles by a transparent media is studied. An example of these applications is the optical Fourier spectrum measurement resulting from various spatial frequencies which were recorded on a photographic emulsion. A method for obtaining these measurements consists of illuminating the test object with parallel monochromatic light. A stationary lens, placed in the resulting wavefield at a distance of one focal length from the object, will focus parallel waves emanating from the test object at a point lying in the focal plane of the lens. A light detector with a small filtering aperture is then used to measure the intensity variation of the light in the focal or transform plane of the lens. Such measurements require the use of a lens which is highly corrected for all of the common aberrations except chromatic aberration.

Ballard, G. S.↗
NASA NTRS1972

Solar particle composition measurements

The composition of solar particle events, that is the relative abundance of different elements, was studied, using nuclear emulsion detectors flown on board sounding rockets. These observations were extended to elements as heavy as iron. A model is discussed in which the particles in a flare are stripped of electrons in the high temperature of a flare region, and subsequently are accelerated presumably by magnetic fields.

Reames, D. V.↗
NASA NTRS1971

Multiband photography - Forestry and agricultural applications.

The usefulness of multiband photography in forestry and agricultural applications was evaluated by a large group of skilled photo interpreters within four California test sites. Environmental parameters selected included crop types, forest vegetation types, and tree species composition. Quantitative analyses were made of the interpretability of (1) multiband black and white photos viewed separately, (2) multiband black and white photos combined into true and false color composites, and (3) color and color infrared photos obtained simultaneously with the multiband black and white photography. Tests indicated that multiband photography consistently yielded higher interpretation accuracies than any types of single-band photography. Black and white multiband photos which were properly procured and displayed as false-color composite imagery in all cases rendered as much (or as little) information as conventional tri-emulsion color or infrared color film.

Lauer, D. T.↗
NASA NTRS1972

Enrichment of very heavy nuclei in the composition of solar accelerated particles.

Measurement of the abundances of the nuclei C, N, O, Ne, Mg, Si, Ar, and Ca and the group Cr-Co relative to oxygen from seven solar energetic-particle events in the energy range from about 14 to 61 MeV per nucleon with a solid-state detector telescope on the OGO-5 satellite, 1968-1971. The differential energy spectra of O (14 to 29 MeV per nucleon) and Cr-Co (3 to 61 MeV per nucleon) have a spectral index of about (-3) for a power law in kinetic energy. The relative abundances of C, N, O, and Ne are in excellent agreement with emulsion studies. However, when compared with the solar photospheric and coronal abundances, the OGO-5 measurements show a large enhancement of relative abundances beginning with Si, and extending to the Cr-Co group. The enhancement over the solar and universal abundances is in rough agreement with the composition of the galactic cosmic radiation.

Mogro-Campero, A.↗