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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 901 records · Page 50
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Rb-Sr systematics for chemically defined Apollo 14 breccias.

The Rb and Sr systematics were determined for eight lithic fragments from the coarse fines of Apollo 11, Apollo 12, and Apollo 14; for bulk soils from Luna 16, Apollo 14, and Apollo 15 and for 'whole rocks' from Apollo 14 and the Apollo 15 anorthosite 15415. The objective of the studies was to identify important lunar rock types by their major and trace element chemistry and utilize Rb and Sr systematics to obtain a chronology for events which establish or modify rock chemical composition.

Nyquist, L. E.↗
NASA NTRS1972

Rare-gas analyses on neutron irradiated Apollo 12 samples.

Argon, krypton, and xenon from stepwise heating of five Apollo 12 rocks that had been irradiated to a neutron fluence of about 10 to the 19th neutrons/sq cm were analyzed mass-spectrometrically. The Ar40-Ar39 ages were determined and range from 3.18 plus or minus 0.06 x 10 to the 9th years to 3.32 plus or minus 0.06 x 10 to the 9th years. Trace elements Ba, Br, I, and U were measured via the neutron-induced reactions that produce isotopes of krypton and xenon. The following concentration ranges were observed: Ba, 46 to 70 ppm; Br, 48 to 146 ppb; I, 16 to 73 ppb; and U, 170 to 247 ppb.

Alexander, E. C., Jr.↗
NASA NTRS1973

Noble gases in eleven H-chondrites.

Review of the results of measurements of noble gases in powdered aliquots of 11 H-chondrites whose trace element contents have been previously determined by Laul et al. (1973). The measurements were made on a 4.5-inch radius, Reynolds-type mass spectrometer, using conventional techniques.

Ganapathy, R.↗
NASA NTRS1973

Chemical composition of Luna 20 rocks and soil and Apollo 16 soils.

Review of the abundances of 24 major, minor, and trace elements measured by instrumental neutron activation analysis in Luna 20 metaigneous rocks, breccia, and soil, and in Apollo 16 soils. The similarities and differences observed are discussed. The bulk compositions of Luna 20 and Apollo 16 rocks and soils show close similarity between the two highland sites. Interelement correlations observed previously for maria are also found in highland samples. Luna 20 and Apollo 16 soils are low in alkalis. Both soils show an apparent Cd-Zn rich component similar to that observed at the mare sites and high Tl abundances relative to mare sites.

Laul, J. C.↗
NASA NTRS1973

Chemistry of lunar basalts with very high alumina contents.

A chemically distinct group of lunar rocks with the trace element characteristics of basaltic lunar rocks is apparently ubiquitous on the lunar surface. Such rocks have been found at the Apollo 15, Apollo 16, and Luna 20 landing sites. They may be derived from the plains-forming material that has been designated Cayley Formation.

Hubbard, N. J.↗
NASA NTRS1973

On the ionization of the intercloud medium by ultraviolet stars.

Analysis of a recently proposed model of the ionization of the intercloud medium by ultraviolet stars, deriving the gas parameters and the ionization structure in the steady-state approximation. A comparison of the theoretical results with satellite ultraviolet observations, if these latter are typical of the intercloud gas and the effect of stellar H II regions is negligible, suggests that the model is unsatisfactory. The main disagreement is in the predicted relative abundances of the higher ionization stages of the trace elements, and in the ratios of successive stages.

Meszaros, P.↗
NASA NTRS1973

Meteoritic material on the moon.

Three types of meteoritic material are found on the moon: micrometeorites, ancient planetesimal debris from the 'early intense bombardment,' and debris of recent, crater-forming projectiles. Their amounts and compositions have been determined from trace element studies. The micrometeorite component is uniformly distributed over the entire lunar surface, but is seen most clearly in mare soils. It has a primitive, Cl-chondrite-like composition, and comprises 1-1.5% of mature soils. The ancient component is seen in highland breccias and soils more than 3.9 AE old. It has a fractionated composition, with volatiles depleted relative to siderophiles. The abundance pattern does not match that of any known meteorite class. The crater-forming component has remained elusive. Only a possible hint of this component has been seen, in ejecta from Dune Crater and Apollo 12 KREEP glasses of possibly Copernican origin.

Anders, E.↗
NASA NTRS1973

Extralunar materials in cone-crater soil 14141.

Radiochemical neutron activation analysis has been used to determine Ni, Zn, Ga, Ge, Cd, In, Ir, and Au in duplicate samples of lunar soil 14141 and in one additional replicate each of soils 14163 and 14259. The concentrations of extralunar trace elements Ni, Ge, Ir, and Au in 14141 and 14163 are, respectively, about 69 and 82% as high as those in 14259. Although most of the mass of 14141 appears to be ejecta from Cone Crater, a sizable contamination by mature Fra Mauro soil such as 14259 is also present. The siderophilic-element concentrations of the subregolith Fra Mauro materials are estimated to be 25 plus or minus 25% of those observed in 14259.

Wasson, J. T.↗
NASA NTRS1973

On the nature of the ionizing agents of the interstellar medium.

The ionization structure of the interstellar trace elements predicted by the steady-state cosmic-ray, X-ray, and ultraviolet star ionization models, even when allowance is made for the stellar H II region, is in disagreement with satellite observations of at least two stars. The conclusion is reached that, in some regions of the Galaxy, the flux of cosmic rays or X-rays is much smaller than was thought previously.

Meszaros, P.↗
NASA NTRS1972

The origin and chemical composition of the earth's core

The process of core formation in the earth is subject to the constraints that it be nearly simultaneous with accretion and yet occur in a manner that the mantle retains radiogenic Xe-129 produced from the extinct radioactivity of I-129 with a half life of 17.6 million y. From these constraints, it appears that the only feasible mechanism is the segregation of an Fe-FeS melt. Trace element abundances in major classes of meteorites and the silicate fractions of the earth show that not only there is a high depletion of sulphur in the crust and the mantle, but that it is even more highly depleted than the rare gases, water and the halogens. From the nature of this depletion pattern and the fact that any model of accretion of the earth will necessarily produce an Fe-FeS melt, it is concluded that the light element in the core is largely sulphur with minor amounts of carbon. A consequence of this mode of core formation is found to be the availability of K-40 radioactive heat production in the liquid core, estimated at about 10 to the 19th power erg/s at the present time.

Murthy, V. R.↗
NASA NTRS1974

Quantitation and detection of vanadium in biologic and pollution materials

A review is presented of special considerations and methodology for determining vanadium in biological and air pollution materials. In addition to descriptions of specific analysis procedures, general sections are included on quantitation of analysis procedures, sample preparation, blanks, and methods of detection of vanadium. Most of the information presented is applicable to the determination of other trace elements in addition to vanadium.

Gordon, W. A.↗
NASA NTRS1973

Chemical composition of Apollo 15, 16, and 17 samples

The authors analyzed 22 Apollo 15 samples, 21 Apollo 16 samples, 4 Luna 20 samples, and 6 Apollo 17 samples for 26 to 30 major, minor, and trace elements by instrumental neutron activation analysis (INAA). Major attention is given to Apollo 16 results and recent Apollo 17 data. The roster of elements via INAA has been extended to include Nd, Ni, Ir, and Au in the Apollo 16 and 17 samples. The latter three elements are highly abundant in these samples. Sample preparation, activation conditions, and the detailed INAA analytical procedure are essentially the same as reported by Laul and Schmitt (1973).

Laul, J. C.↗
NASA NTRS1974

Preliminary data on lunar surface material returned by Luna 16 automatic station

Results of preliminary investigations of a sample of lunar surface material returned by Luna 16 automatic station are reported. Information on the granulometric characteristics of regolith, its optical properties, types of its constituent rocks, and its mineral composition is given. The chemical composition of major and trace elements for different sections of the core and for the lunar basalt was determined. Isotopic composition of inert gases and of several elements was studied. The Rb/Sr age was determined at 4.85 to 4.25 billion years.

Vinogradov, A. P.↗
NASA NTRS1975

Development and testing of a portable wind sensitive directional air sampler

A portable wind sensitive directional air sampler was developed as part of an air pollution source identification system. The system is designed to identify sources of air pollution based on the directional collection of field air samples and their analysis for TSP and trace element characteristics. Sources can be identified by analyzing the data on the basis of pattern recognition concepts. The unit, designated Air Scout, receives wind direction signals from an associated wind vane. Air samples are collected on filter slides using a standard high volume air sampler drawing air through a porting arrangement which tracks the wind direction and permits collection of discrete samples. A preset timer controls the length of time each filter is in the sampling position. At the conclusion of the sampling period a new filter is automatically moved into sampling position displacing the previous filter to a storage compartment. Thus the Air Scout may be set up at a field location, loaded with up to 12 filter slides, and left to acquire air samples automatically, according to the wind, at any timer interval desired from 1 to 30 hours.

Deyo, J.↗
NASA NTRS1974

Chemical composition of boulder-2 rocks and soils, Apollo 17, Station 2

The bulk and trace element composition of five small samples from four rocks is remarkably similar. This result indicates that the metaclastic rocks studied are relatively uniform in their chemical composition. The elemental abundances found in the study are presented in two tables and the implications of the data are considered, giving attention to siderophiles, atmophile elements, and questions of element correlations. The 'dark mantle' valley soil 75081 at Camelot Crater is low in siderophiles. Since the soil is low in alkalis, a derivation from low-alkali mare basalt is suggested. The identical volatile contents in the surface soil 72461 and the 4 cm depth soil 72441 under a 0.7 m boulder argue against any surficial volatization by galactic and solar particles.

Laul, J. C.↗
NASA NTRS1974

Lunar mascons - Another model and its implications

A mascon model is proposed in which the mass excess of the mare basalts in the circular maria is supported isostatically by mass deficits at depth. The model predicts the observed positive gravity anomalies surrounded by negative ring anomalies and explains the absence of gravity anomalies over the irregular maria. The model implies that mare basalts were derived by partial melting of a source region at depth due to pressure relief resulting from the excavation of the circular mare basins, and that the crystalline residuum in the source region is of lower density than the original source rock. The trace element enrichment and near cotectic character of Apollo 11 and 12 lavas reported by some investigators may be caused by extensive magma fractionation enroute from an origin in the circular maria to the final, distant emplacement sites.

Kunze, A. W. G.↗
NASA NTRS1975

Air pollution source identification

Techniques for air pollution source identification are reviewed, and some results obtained with them are evaluated. Described techniques include remote sensing from satellites and aircraft, on-site monitoring, and the use of injected tracers and pollutants themselves as tracers. The use of a large number of trace elements in ambient airborne particulate matter as a practical means of identifying sources is discussed in detail. Sampling and analysis techniques are described, and it is shown that elemental constituents can be related to specific source types such as those found in the earth's crust and those associated with specific industries. Source identification sytems are noted which utilize charged particle X-ray fluorescence analysis of original field data.

Fordyce, J. S.↗
NASA NTRS1975

Development and testing of a portable wind sensitive directional air sampler

A portable wind-sensitive directional air sampler has been developed as part of an air pollution source identification system. The system is designed to identify sources of air pollution based on the directional collection of field air samples and their analysis for TSP and trace element characteristics. Sources can be identified by analyzing the data on the basis of pattern recognition concepts. Functional testing of a prototype sampler is described; all items exhibited performance and life sufficient to carry out field performance test operations. Life testing of the wind direction sensor and the directional porting valves, which are critical to reliable operation, was emphasized with successful results.

Deyo, J.↗