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At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Chemical analysis of outgassing contaminants on spacecraft surfaces

Methods for analyzing and characterizing outgassing contaminants from such materials as RTV 501 potting compound and S 13 G paint are presented. Fractional distillation of a gross distillate from RTV 501 rubber was carried out and the distilled fractions examined as to their ultraviolet and infrared spectra by gas liquid chromatography. A sensitive technique for structural analysis and molecular identification was found to consist of a gas chromatography-mass spectroscopy system, which was determined to be economically unfeasible at present.

Mcnutt, R. C.↗
NASA NTRS1977

A forward-scatter polarimeter for chemical analysis

Photopolarimeter measures two states of orthogonal polarization parallel and perpendicular to scattering plane, defined by directions of incident and scattering light, to determine effective gaseous depolarization factor. Instrument can be used for environmental, spectroscopic, and meteorological analysis.

Fymat, A. L.↗
NASA NTRS1976

Chemical Analysis of Outgassing Contaminants on Spacecraft Surfaces

Samples of S-13 paint on aluminum, reflection grating anomalies as affected by dielectric coatings, and rocket effluents were analyzed along with Skylab window scrapings and a gas activated semiconductor. Development of an HCl detector is also discussed. Results are briefly summarized.

Mcnutt, R. C.↗
NASA NTRS1986

Chemical analysis of aerosol in the Venusian cloud layer by reaction gas chromatography on board the Vega landers

The experiment on sulfuric acid aerosol determination in the Venusian cloud layer on board the Vega landers is described. An average content of sulfuric acid of approximately 1 mg/cu m was found for the samples taken from the atmosphere at heights from 63 to 48 km and analyzed with the SIGMA-3 chromatograph. Sulfur dioxide (SO2) was revealed in the gaseous sample at the height of 48 km. From the experimental results and blank run measurements, a suggestion is made that the Venusian cloud layer aerosol consists of more complicated particles than the sulfuric acid water solution does.

Gelman, B. G.↗
NASA NTRS1986

Spectrum and chemical analysis of the double-ring planetary nebula IC 1297

The double-ring planetary nebula IC 1297 resembles NGC 7662 in appearance, although it is of much lower surface brightness. What is remarkable is the great strength of the dielectronic recombination O V line. Although this line is seen as a P Cygni feature in a number of planetary nebulae, it is in those instances accompanied by a strong continuum and other easily recognized features of stellar origin. No star is visible on CCD images of IC 1297. Optical region measurements are supplemented by IUE observations. The following logarithmic abundance values are found: log N(He) = 11.065; log N(forbidden C) = 8.6; log N(N) = 8.1; log N(O) = 8.74; log N(Ne) = 8.16; log N(S) = 7.0; log N(Cl) = 5.4; log N(Ar) = 6.2. The nebula shows no dramatic pattern of nucleogenesis events.

Aller, Lawrence H.↗
NASA NTRS1989

Electron spectroscopy for chemical analysis: Sample analysis

Exposure conditions in atomic oxygen (ESCA) was performed on an SSL-100/206 Small Spot Spectrometer. All data were taken with the use of a low voltage electron flood gun and a charge neutralization screen to minimize charging effects on the data. The X-ray spot size and electron flood gun voltage used are recorded on the individual spectra as are the instrumental resolutions. Two types of spectra were obtained for each specimen: (1) general surveys, and (2) high resolution spectra. The two types of data reduction performed are: (1) semiquantitative compositional analysis, and (2) peak fitting. The materials analyzed are: (1) kapton 4, 5, and 6, (2) HDPE 19, 20, and 21, and (3) PVDF 4, 5, and 6.

Carter, W. B.↗
NASA NTRS1991

Chemical analysis of metal and polymer surfaces on the front and rear LDEF

The University of Alabama in Huntsville experiment AO114 contained 128 solid surface samples, half of which were exposed on the front and half on the rear of the Long Duration Exposure Facility (LDEF). Each sample is being subject to a battery of analysis methods. In poster form, details of the x-ray photoelectron spectra, Auger electron spectra, Fourier Transform Infrared and ATR infrared spectra, high resolution profilometry, and scanning electron microscope imagery will be presented from a selection of metal and non-metal surfaces.

Christi, L.↗
NASA NTRS1991

Organic chemical analysis on a microscopic scale using two-step laser desorption/laser ionization mass spectrometry

The distribution of PAHs in the Allende meteorite has been measured using two-step laser desorption and laser multiphoton-ionization mass spectrometry. This method enables in situ analysis (with a spatial resolution of 1 mm or better) of selected organic molecules. Results show that PAH concentrations are locally high compared to the average concentration found by analysis of pulverized samples, and are found primarily in the fine-grained matrix; no PAHs were detected in the interiors of individual chondrules at the detection limit (about 0.05 ppm).

Kovalenko, L. J.↗
NASA NTRS1993

An x ray scatter approach for non-destructive chemical analysis of low atomic numbered elements

A non-destructive x-ray scatter (XRS) approach has been developed, along with a rapid atomic scatter algorithm for the detection and analysis of low atomic-numbered elements in solids, powders, and liquids. The present method of energy dispersive x-ray fluorescence spectroscopy (EDXRF) makes the analysis of light elements (i.e., less than sodium; less than 11) extremely difficult. Detection and measurement become progressively worse as atomic numbers become smaller, due to a competing process called 'Auger Emission', which reduces fluorescent intensity, coupled with the high mass absorption coefficients exhibited by low energy x-rays, the detection and determination of low atomic-numbered elements by x-ray spectrometry is limited. However, an indirect approach based on the intensity ratio of Compton and Rayleigh scattered has been used to define light element components in alloys, plastics and other materials. This XRS technique provides qualitative and quantitative information about the overall constituents of a variety of samples.

Ross, H. Richard↗
DOE OSTI2020

Production of National Nuclear Material Archive Subsamples for High Precision Chemical Analysis

With its historical mission as the focal point for production of uranium components for the NNSA nuclear weapons program, the National Nuclear Materials Archive (NNMA) makes use of Y-12's wide range of uranium materials processing knowledge and onsite materials to identify, collect, and preserve sample materials for nuclear forensics purposes. In 2019, Y-12 took on the responsibility for identifying, subsampling, and shipping a total of 24 NNMA samples to the Lawrence Livermore National Laboratory (LLNL) for further forensics analysis. These were highly enriched uranium metal pieces representative of different weapon systems components produced by Y-12 from approximately 1963 to 1993. The purpose was to provide the NNMA program with higher precision analyses of these materials than what is currently available from historical Y-12 production stream data.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗