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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 1,045 records · Page 58
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

Very low-Ti mare basalts

Bulk compositions, petrology, and mineralogy of lithic fragments discovered in polished sections of Apollo 17 drill core samples 70007, 70008, and 70009 and Luna 24 soil 24077, 43 are described. The fragments have unambiguous affinities to mare basalts, but are exceptionally low in TiO2 (less than 1.0 wt.% TiO2). Apollo 17 rake sample 78526 is a green glassy rock of similar composition. Together the samples represent a distinct variety of mare basalts. Bulk compositional relationships suggest that they are related to Apollo 15 green glass, but the data do not permit one to discern the precise nature of the relationship. Both fractional crystallization and partial melting models can explain the observed compositional trends.

Taylor, G. J.↗
NASA NTRS1978

Experimental petrology of very low Ti /VLT/ basalts

Synthetic analogs of Luna 24 ferrobasalt and an Apollo 15 green glass were subjected to iron capsule experiments to test hypotheses concerning the generation of Luna 24 ferrobasalt. Results of the experiments indicated that the Luna 24 ferrobasalt may be generated by near-surface fractionation of a Luna 24 green glass parent. Evidence for the parent magma which differentiated at or near the Mare Crisium site to yield the Luna 24 ferrobasalt may be found in the Luna 24 green glass and lithic fragments of vitrophyres.

Grove, T. L.↗
NASA NTRS1980

Atomic data and level populations of highly ionized Ti for tokamak plasmas

The paper presents calculations of electron impact collision strengths and spontaneous radiative decay rates for titanium ions of the LiI through FI isoelectronic sequences for transitions between levels of the 2S(2)2p(k), 2s2p(k+1), and 2p(k+2) configurations. From these atomic data, excitation-rate coefficients are calculated along with level populations for these three configurations. The calculations of level populations include the effects of proton excitation, and are carried out at electron temperatures and densities typical of tokamak plasmas. Wavelengths of forbidden and intersystem lines are given, and a synthetic spectrum is presented for a typical temperature and density.

Bhatia, A. K.↗
NASA NTRS1981

Evaporated As2S3 Luneburg lenses for LiNbO3:Ti optical waveguides

Luneburg lenses of good quality were formed on high index optical waveguides by evaporation of arsenic trisulfide glass through simple masks. Using only two thin circular aperture masks, lenses with focal spots of a few times the diffraction limited width at f/4 were obtained. These lenses were designed for and tested at both visible (633 nm) and infrared wavelengths. Procedures for the design, fabrication, and testing of lenses of this type are described.

Busch, J. R.↗
NASA NTRS1981

Evaluation of superplastic forming and co-diffusion bonding of Ti-6Al-4V titanium alloy expanded sandwich structures

The application of the superplastic forming/diffusion bonding (SPF/DB) process to supersonic cruise research is investigated. The capability of an SPF/DB titanium structure to meet the structural requirements of the inner wing area of the NASA arrow-wing advanced supersonic transport design is evaluated. Selection of structural concepts and their optimization for minimum weight, SPF/DB process optimization, fabrication of representative specimens, and specimen testing and evaluation are described. The structural area used includes both upper and lower wing panels, where the upper wing panel is used for static compression strength evaluation and the lower panel, in tension, is used for fracture mechanics evaluations. The individual test specimens, cut from six large panels, consist of 39 static specimens, 10 fracture mechanics specimens, and one each full size panel for compression stability and fracture mechanics testing. Tests are performed at temperatures of -54 C (-65 F), room temperature, and 260 C (500 F).

Arvin, G. H.↗
NASA NTRS1980

Ion microprobe analysis and petrogenetic interpretations of Li, Mg, Ti, K, Sr, Ba in lunar plagioclase

The ion microprobe employed in the considered investigation utilizes a focused primary ion beam to sputter a tiny volume of a sample. A small fraction of the sputtered atoms is ionized and extracted from the sample region for subsequent analysis with a mass spectrometer. A systematic study was conducted to determine which elements can be detected and analyzed in lunar Ca-rich plagioclase. Attention is given to the method of quantitative determination, the selected samples, and aspects of data presentation. A number of general conclusions are discussed. All minor elements in plagioclases from anorthosites from several lunar sites show a restricted range consistent with a common origin. The simplest interpretation is that the anorthosites developed from a moon-wide event, or at least from closely-related events. A moon-wide magma ocean would satisfy this condition.

Steele, I. M.↗
NASA NTRS1986

Excess depletion of Al, Ca, Ti from interstellar gas

Thermal condensation, cold sticking, and sputtering by interstellar shock are combined with a chemical memory of the condensation sequence to account for depletion of aluminum, calcium, and titanium in interstellar gas. The extra depletion of aluminum and calcium becomes an indicator of the structural history of the refractory parts of interstellar grains.

Clayton, D. D.↗
NASA NTRS1985

Abundances of O, Mg, S, Cr, Mn, Ti, Ni and Zn from absorption lines of neutral gas in the Large Magellanic Cloud in front of R136

Weak absorption lines of C I, O I, Mg I, Mg II, Si I, Si II, P I, Cl I, Cr II, Mn II, Fe I, Ni II, Zn II, CO and C2 are detected in neutral gas in front of the 30 Doradus H II region by IUE spectra of R 136. The Large Magellanic Cloud abundances from the absorption lines are a factor of 2 or 3 below those of the Milky Way, in agreement with emission line study results. Neutral gas density and temperature are estimated from the observed excitation and ionization to be about 300/cu cm and 100 K, respectively; this implies a gas pressure of 30,000/cu cm K.

De Boer, K. S.↗