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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 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Validity of trace element cosmothermometer

A reply is made to previous criticisms of the claim that the range of accretion of ordinary chondrites can be narrowed to 500-420 K (from 560-405 K) using volatile metals as cosmothermometers. Questions concerning uncertainties in vapor pressure data, entropy of mixing, methods of analysis, uncertainties in condensation curves, metamorphic transport, alloy formation, condensation of Tl, condensation of In, and concordance with other thermometers (FeO contents of silicates) are addressed. It is concluded that the original claim is valid.

Anders, E.↗
NASA NTRS1976

An Investigation of Size-Dependent Concentration of Trace Elements in Aerosols Emitted from the Oil-Fired Heating Plants

Aerosols emitted from two oil-fired heating plants were aerodynamically separated into eight size groups and were analyzed using the photon-induced X-ray emission (PIXE) technique. It was found that Zn, Mo, Ag, and Pb, and (to a lesser extent) Cd, have a tendency to concentrate preferentially on the smaller aerosols. All of these elements, in certain chemical forms, are known to be toxic. Zinc and molybdenum, although present in low concentrations in the parent fuels, show the strongest tendencies to be concentrated in finer aerosols. Selenium, previously reported to show a very strong tendency to concentration in finer fly ash from coal-fired power plants shows little preference for surface residence. Vanadium, which occurs in significant concentration in the oil fuels for both plants, also shows little preference for surface concentration. Even though the absolute concentrations of the toxic elements involved are well below the safety levels established by the National Institute for Occupational Safety and Health (NIOSH), it would be advisable to raise the heights of the heating-plant exhaust chimneys well above the neighborhood buildings to insure more efficient aerosol dispersal.

Singh, J. J.↗
NASA NTRS1976

Concentrations of trace elements and compounds in the airborne suspended particulate matter in Cleveland, Ohio, from August 1971 to August 1972 and their dependence on wind direction: Complete data listing and concentration roses

Concentrations of 75 chemical constituents in the airborne particulate matter were measured in Cleveland, Ohio during 1971 and 1972. Daily values, maxima, geometric means and their standard deviations covering a 1-year period (45 to 50 sampling days) at each of 16 sites are presented on microfiche for 60 elements, and for a lesser number of days for 10 polycyclic aromatic hydrocarbon compounds (PAH), the aliphatic hydrocarbon compounds (AH) as a group and carbon. In addition, concentration roses showing directional properties are presented for 39 elements, 10 PAH and the AH as a group. The elements (except carbon) are shown both in terms of concentration and percentage of the suspended particulate matter.

King, R. B.↗
NASA NTRS1976

Convection cells in the early lunar magma ocean - Trace-element evidence

A method was proposed for recognizing suites of samples which are related to the differentiation of distinct and regionally separated magmas in the early lunar surface ocean. The sample suites were identified by three Cl-P2O5 compositional groups. New experimental data continue to add samples to these groups. Each magma was associated with a convection cell the boundaries of which are proposed. Independent geochemical evidence supporting a limited number of early magmas is cited. Two new possible Cl-P2O5 groups are identified. Samples not indigenous to a given site and their possible source regions are identified. It is proposed that many Apollo 17 basalts are not locally derived.

Jovanovic, S.↗
NASA NTRS1976

Trace element evidence regarding a chondritic component in howardite meteorites

The concentrations of siderophiles Ni, Ge, Ru, Ir, and Au and volatiles Zn, Ga, Cd, and In in howardite meteorites were determined and are discussed along with similar data for eucrites and diogenites. The concentrations of the chondritic component in howardites are remarkably high. The concentrations in four high-siderophile howardites are comparable to those found in mature soils from the lunar highlands. The amounts of excess volatiles are roughly consistent with those expected if the chondritic component resemble CI, CM, or E4 chondrites. Evidence indicates that the howardite parent body had a radius of several hundred kilometers, and the most probable formation location was 1-2 AU from the sun.

Chou, C.-L.↗