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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
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 NTRS1978

Chemistry of orange/black soils from core 74001/2

Double core 74001/2 soils were studied. Bulk soils and the 90-150 micrometer and less than 20 micrometer size fractions of 13 soils from the core for both major and trace elements by instrumental neutron activation analysis were analyzed. The orange and black glassy soils in the core 74001/2 are homogeneous in composition and due to their unusual compositional characteristics probably have derived from a single source with the same composition. The top of the core has been reworked to a depth of about 5 cm. The reworked layer is marked by compositional differences in the first 3 cm which reflect the addition (at least 10%) of materials including mare basalt and a CaO-rich component. The maturity profile (I sub s/FeO) clearly indicates reworking depth of about 5 cm. It is likely that at least some of the ferro-magnetically active component (including agglutinitic glass) has been 'inherited' with the added material.

Blanchard, D. P.↗
NASA NTRS1988

A chemical and isotopic study of hibonite-rich refractory inclusions in primitive meteorites

Isotopic and chemical analyses of hibonite-rich inclusions from a number of primitive meteorites and, in some cases, of coexisting minerals from carbonaceous and ordinary chondrites, were carried out using ion microprobe (IP). The results of the IP analyses were compared with literature data obtained by INAA and electron microprobe analysis. Results showed that the trace element patterns of the hibonite inclusions analyzed have a number of feautures in common. The results are discussed with reference to the possible chemical processes operating early in the history of the solar system.

Hinton, Richard W.↗
NASA NTRS1993

TransFit: Finite element analysis data fitting software

The Advanced X-Ray Astrophysics Facility (AXAF) mission support team has made extensive use of geometric ray tracing to analyze the performance of AXAF developmental and flight optics. One important aspect of this performance modeling is the incorporation of finite element analysis (FEA) data into the surface deformations of the optical elements. TransFit is software designed for the fitting of FEA data of Wolter I optical surface distortions with a continuous surface description which can then be used by SAO's analytic ray tracing software, currently OSAC (Optical Surface Analysis Code). The improved capabilities of Transfit over previous methods include bicubic spline fitting of FEA data to accommodate higher spatial frequency distortions, fitted data visualization for assessing the quality of fit, the ability to accommodate input data from three FEA codes plus other standard formats, and options for alignment of the model coordinate system with the ray trace coordinate system. TransFit uses the AnswerGarden graphical user interface (GUI) to edit input parameters and then access routines written in PV-WAVE, C, and FORTRAN to allow the user to interactively create, evaluate, and modify the fit. The topics covered include an introduction to TransFit: requirements, designs philosophy, and implementation; design specifics: modules, parameters, fitting algorithms, and data displays; a procedural example; verification of performance; future work; and appendices on online help and ray trace results of the verification section.

Freeman, Mark↗
NASA NTRS1988

Trace element and isotope geochemistry of Cretaceous-Tertiary boundary sediments: identification of extra-terrestrial and volcanic components

Trace element and stable isotope analyses were performed on a series of sediment samples crossing the Cretaceous-Tertiary (K-T) boundary from critical sections at Aumaya and Sopelano, Spain. The aim is to possibly distinguish extraterrestrial vs. volcanic or authigenic concentration of platinum group and other elements in K-T boundary transitional sediments. These sediments also have been shown to contain evidence for step-wise extinction of several groups of marine invertebrates, associated with negative oxygen and carbon isotope excursions occurring during the last million years of the Cretaceous. These isotope excursions have been interpreted to indicate major changes in ocean thermal regime, circulation, and ecosystems that may be related to multiple events during latest Cretaceous time. Results to date on the petrographic and geochemical analyses of the Late Cretaceous and Early Paleocene sediments indicate that diagenesis has obviously affected the trace element geochemistry and stable isotope compositions at Zumaya. Mineralogical and geochemical analysis of K-T boundary sediments at Zumaya suggest that a substantial fraction of anomalous trace elements in the boundary marl are present in specific mineral phases. Platinum and nickel grains perhaps represent the first direct evidence of siderophile-rich minerals at the boundary. The presence of spinels and Ni-rich particles as inclusions in aluminosilicate spherules from Zumaya suggests an original, non-diagenetic origin for the spherules. Similar spherules from southern Spain (Caravaca), show a strong marine authigenic overprint. This research represents a new approach in trying to directly identify the sedimentary mineral components that are responsible for the trace element concentrations associated with the K-T boundary.

Margolis, S. V.↗
NASA NTRS2003

Syringe filtration methods for examining dissolved and colloidal trace element distributions in remote field locations

It is well-established that sampling and sample processing can easily introduce contamination into dissolved trace element samples if precautions are not taken. However, work in remote locations sometimes precludes bringing bulky clean lab equipment into the field and likewise may make timely transport of samples to the lab for processing impossible. Straightforward syringe filtration methods are described here for collecting small quantities (15 mL) of 0.45- and 0.02-microm filtered river water in an uncontaminated manner. These filtration methods take advantage of recent advances in analytical capabilities that require only small amounts of waterfor analysis of a suite of dissolved trace elements. Filter clogging and solute rejection artifacts appear to be minimal, although some adsorption of metals and organics does affect the first approximately 10 mL of water passing through the filters. Overall the methods are clean, easy to use, and provide reproducible representations of the dissolved and colloidal fractions of trace elements in river waters. Furthermore, sample processing materials can be prepared well in advance in a clean lab and transported cleanly and compactly to the field. Application of these methods is illustrated with data from remote locations in the Rocky Mountains and along the Yukon River. Evidence from field flow fractionation suggests that the 0.02-microm filters may provide a practical cutoff to distinguish metals associated with small inorganic and organic complexes from those associated with silicate and oxide colloids.

Colloids/analysis↗
NASA NTRS1980

Trace elements in ocean ridge basalt glasses - Implications for fractionations during mantle evolution and petrogenesis

Seven documented and fresh glassy selvages from ocean floor basalt pillows were analyzed for trace elements including Ag, Au, Bi, Br, Ni, Pd, and Zn using radiochemical activation analysis. Glasses from DSDP leg 24, site 238 in the Indian Ocean have a trace element pattern which reflects secondary processes at a shallow depth. Chemical fractionations in petrogenesis of tholeiitic basalts indicate that (Ir, Os), Au, Pd, Ni, and Re are strongly fractionated in igneous processes; the unfractionated chondritic mantle pattern thus imposes constraints on mantle evolution models. Finally, the limited Rb/Cs fractionation in oceanic tholeiites reflects the low abundance of volatiles and hydrous silicates in normal ocean ridge basalts.

Hertogen, J.↗
NASA NTRS1973

Luna 20 soil - Abundance of 17 trace elements.

Review of the results of radiochemical neutron activation analysis of two Luna 20 fine soil and breccia samples for the abundance of 17 mainly siderophile and volatile elements that are strongly depleted in lunar surface rocks and hence represent sensitive indicators of meteoritic materials. These results are compared with those previously obtained for Apollo 16 soils. Some of the source rocks of Luna 20 regolith are identified.

Morgan, J. W.↗
NASA NTRS1977

Genesis of the Angra dos Reis and other achondritic meteorites

Major, minor, and trace element abundances were determined in seven Angra dos Reis samples, which included whole rocks, fassaite (clinopyroxene), olivine, and whitlockite separates, via sequential instrumental neutron activation analysis. The rare earth element abundance patterns and the trace element abundance patterns of this achondritic meteorite are discussed. A two-stage crystal-liquid fractionation model with source material containing olivine, orthopyroxene, and clinopyroxine is presented for the genesis of Angra dos Reis. Multilinear regression analysis was used to estimate possible composition and properties of the parent magmas. Angra dos Reis was compared with other achondrites, cumulate eucrites and nakhlites in particular. It is thought that the unique Angra dos Reis could not be related to those achondrites by crystal-liquid fractionation of the same parent body.

Ma, M.-S.↗
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 NTRS1975

Meteoritic trace elements in lunar rock 14321, 184

Measurements are given for sixteen trace elements determined by radiochemical neutron activation analysis in six samples of four components of lunar rock 14321, 184. The samples were of basalt (1B), matrix (9A), microbreccia-2 (15), and microbreccia-3 (14A, 16A, and 19A) components. The ancient meteoritic components in the samples were determined according to the ratios of siderophile elements (Ir/Au and Ge/Au) found in the samples.

Morgan, J. W.↗
NASA NTRS1979

The mean age of mantle and crustal reservoirs

An analysis of two transport models for trace elements in mantle and crust evolution and related to the observed abundance patterns. In model I, continents are derived by melt extraction over the earth history from undepleted mantle, and the residue forms a depleted mantle which is the current source of mid-ocean ridge basalts. In model II, new additions to continents are derived from a mantle reservoir 2, which becomes more depleted by repeated extraction of melts. The isotopic composition and concentrations of trace elements are shown to reduce to simple mathematical expressions which permit calculations of basic evolutionary parameters. The mean age of the crust mass and isotopic data for the continental crust and the mantle are discussed, concluding with a consideration of their difference in compositions of newly derived crust.

Jacobsen, S. B.↗
NASA NTRS1983

Processing of extraterrestrial materials by high temperature vacuum vaporization

It is noted that problems associated with the extraction and concentration of elements and commpounds important for the construction and operation of space habitats have received little attention. High temperature vacuum vaporization is considered a promising approach; this is a technique for which the space environment offers advantages in the form of low ambient pressures and temperatures and the possibility of sustained high temperatures via solar thermal energy. To establish and refine this new technology, experimental determinations must be made of the material release profiles as a function of temperature, of the release kinetics and chemical forms of material being transported, and of the various means of altering release kinetics. Trace element data determined by neutron activation analysis of meteorites heated to 1400 C in vacuum is summarized. The principal tool, high temperature spectrometry, is used to examine the vaporization thermodynamics and kinetics of major and minor elements from complex multicomponent extraterrestrial materials.

Grimley, R. T.↗
NASA NTRS1990

Solutions to problems of weathering in Antarctic eucrites

Neutron activation analysis was performed for major and trace elements on a suite of eucrites from both Antarctic and non-Antarctic sources. The chemistry was examined to see if there was an easy way to distinguish Antarctic eucrites that had been disturbed in their trace elements systematics from those that had normal abundances relative to non-Antarctic eucrites. There was no simple correlation found, and identifying the disturbed meteorites still remains a problem. In addition, a set of mineral separates from an eucrite were analyzed. The results showed no abnormalities in the chemistry and provides a possible way to use Antarctic eucrites that were disturbed in modelling of the eucrite parent body.

Strait, Melissa M.↗
NASA NTRS1991

Microprobe studies of microtomed particles of white druse salts in shergottite EETA 79001

The white druse material in Antarctic shergottite EETA 79001 has attracted much attention as a possible sample fo Martian aqueous deposits. Instrumental Neutron Activation Analysis (INAA) was used to determine trace element analyses of small particles of this material obtained by handpicking of likely grains from broken surfaces of the meteorite. Electron microprobe work was attempted on grain areas as large as 150x120 microns. Backscattered electron images show considerable variations in brightness, and botryoidal structures were observed. Microprobe analyses showed considerable variability both within single particles and between different particles. Microtomed surfaces of small selected particles were shown to be very useful in obtaining information on the texture and composition of rare lithologies like the white druse of EETA 79001. This material is clearly heterogeneous on all distance scales, so a large number of further analyses will be required to characterize it.

Lindstrom, D. J.↗