Seasonal variations in the thermosphere and exosphere, 1968-70
Seasonal density variations in thermosphere and exosphere, obtaining model from Explorers 19 and 39 drag measurements for comparison with OGO-6 mass spectroscopy
Keating, G. M.↗
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Isotopic abundances of actinide elements in Apollo 12 samples
Isotopic abundances and composition of U and Th in Apollo 12 soil and breccia samples, using mass spectroscopy
Diamond, H.↗
Stepwise heating analyses of rare gases from pile-irradiated rocks 10044 and 10057
Ar, Kr and Xe emanation during stepwise heating of lunar rocks under slow neutron irradiation in pile, using mass spectroscopy
Davis, P. K.↗
The search for organic compounds in various Apollo 12 samples by mass spectrometry
Apollo 12 lunar surface samples analysis for organic compounds by mass spectroscopy and pyrolysis-gas chromatography
Biemann, K.↗
Applications of artificial intelligence for chemical inference. V.
Discussion of the modification of the DENDRAL computer program to extend the program to cyclic structures which exceed numerically the linear molecules of a given composition. IR, NMR and mass spectroscopy is used to develop a method for identification of each of the 27 possible ketones (exclusive of 5 cyclopropanones) of composition C6H10O.
Sheikh, Y. M.↗
Organic matter in meteorites.
The meteorites known as carbonaceous chondrites contain organic compounds. These compounds were subjected to detailed analyses which indicate an abiotic origin. Results for the Murchison meteorite are compared with the Murray meteorite, another carbonaceous chondrite. A combined gas chromatography and mass spectroscopy technique was used for the analysis. Results showed a similarity between the two chondrites, in that at least 18 amino acids were present in both, and nine of these could be separated into the D and L forms, present in equal abundance for each amino acid. The amino acids in the Murchison meteorite were found to be optically inactive. At least 23 aromatic hydrocarbons were revealed in the Murchison meteorite by the combined chromatography-spectroscopy technique. The meteorite contained all possible isomers of amino acids with two and three carbon atoms, and all but two of the isomers of amino acids with four carbon atoms. This distribution suggests a random synthesis of the amino acids, rather than a selective synthesis by organisms.
Lawless, J. G.↗
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.↗
An evaluation of pyrolytic techniques with regard to the Apollo 11, 12 and 14 lunar samples analyses.
The first technique involved pyrolysis at 700 C under an inert atmosphere in a flowing He system at normal pressure. The products were collected at liquid nitrogen temperature and then allowed to pass instantaneously into a combined capillary gas chromatograph-mass spectrometer. The second technique consisted of a vacuum pyrolysis where the sample was first degassed at 150 C and then pyrolized at 500 C and 1000 C consecutively. The products were again collected at liquid nitrogen temperature and then they were directly introduced to the ion source of the mass spectrometer through a modified gas inlet system. The experiments have shown the importance of taking into account the factors that influence pyrolytic degradation and/or the synthesis of products. Pyrolysis of Apollo 14 lunar fines and scrapings from an astronaut's glove gave different products by mass spectroscopy and showed different looking flaky materials upon scanning electron microscopy.
Nagy, B.↗
Study of carbon compounds in Apollo 12 and 14 lunar samples.
The results of gas-chromatography and high-resolution mass spectroscopy studies of gases released on deuterium fluoride dissolution of Apollo 12 and 14 lunar samples are reported. The results confirm previous observations that CH4 and C2H6 are released as well as CD4, C2D4, C2D6, and higher deuterated hydrocarbons. The yields correlate with the total carbon content of the samples, and the CH4 and C2H6 released may be regarded as indigenous, while the deuterated products result from hydrolysis of carbide material. The results provide the first experimental confirmation of the hypothesis that the CH4 derives from solar wind interactions.
Holland, P. T.↗
Stress corrosion in titanium alloys and other metallic materials
Multiple physical and chemical techniques including mass spectroscopy, atomic absorption spectroscopy, gas chromatography, electron microscopy, optical microscopy, electronic spectroscopy for chemical analysis (ESCA), infrared spectroscopy, nuclear magnetic resonance (NMR), X-ray analysis, conductivity, and isotopic labeling were used in investigating the atomic interactions between organic environments and titanium and titanium oxide surfaces. Key anhydrous environments studied included alcohols, which contain hydrogen; carbon tetrachloride, which does not contain hydrogen; and mixtures of alcohols and halocarbons. Effects of dissolved salts in alcohols were also studied. This program emphasized experiments designed to delineate the conditions necessary rather than sufficient for initiation processes and for propagation processes in Ti SCC.
Harkins, C. G.↗
Distribution of inert gases in fines from the Cayley-Descartes region
The inert gases in 14 different fines and in one sample of 2 to 4 mm fines from Apollo 16 were measured by mass spectroscopy with respect to trapped solar wind gases, cosmogenic gases, and 'parentless' Ar-40. Such studies are helpful for the understanding of regolith evolution, of transport of regolith fines, and of the lunar atmosphere. The Apollo 16 soils are unique because they represent, after Luna 20, the second and much more extensive record from the lunar highlands. The landing site presents the problem of materials from the Cayley Formation vs those from the Descartes Formation. There are two large, relatively fresh craters in the area, North Ray and South Ray, whose ejecta patterns may be recognized in the inert-gas record.
Walton, J. R.↗
Mass spectrometry
Review of the present status of mass spectrometry in the light of pertinent recent publications spanning the period from December 1971 to January 1974. Following an initial survey of techniques, instruments, and computer applications, a sharp distinction is made between the chemistry of organic (radical-)ions and analytical applications in biorganic chemistry and medicine. The emphasis is on the chemistry of organic (radical-)ions at the expense of inorganic, organometallic, and surface ion chemistry. Biochemistry and medicine are chosen because of their contemporary importance and because of the stupendous contributions of mass spectroscopy to these fields in the past two years. In the review of gas-phase organic ion chemistry, special attention is given to studies making significant contributions to the understanding of ion chemistry.
Burlingame, A. L.↗
Hot hydrogen atoms reactions of interest in molecular evolution and interstellar chemistry
Hot hydrogen atoms which are photochemically generated initiate reactions among mixtures of methane, ethane, water and ammonia, to produce ethanol, organic amines, organic acids, and amino acids. Both ethanol and ethyl amine can also act as substrates for formation of amino acids. The one carbon substrate methane is sufficient as a carbon source to produce amino acids. Typical quantum yields for formation of amino acids are approximately 0.00002 to 0.00004. In one experiment, 6 protein amino acids were identified and 8 nonprotein amino acids verified utilizing gas chromatography-mass spectroscopy. We propose that hot atoms, especially hydrogen, initiate reactions in the thermodynamic nonequilibrium environment of interstellar space as well as in the atmospheres of planets.
Becker, R. S.↗
Preliminary results Skylab experiment TO27 optical contamination in space
Current results from the TO27 experiment which was performed on the first two Skylab missions are presented. The purpose of the experiment was to determine the change in optical properties of various transmissive windows, mirrors, and diffraction gratings caused by the deposition of contaminants found about the orbital assembly and to measure the sky brightness background caused by solar illumination of particulate contaminants. The sample array system containing 248 optical surfaces and exposed outside the orbital workshop did not collect any significant contaminants. Only trace amounts of surface deposited contaminants have been seen, in all cases the measurement was near the limiting sensitivity of the instrument. Unfortunate performance compromises and the relative cleanliness of the assembly on the anti-solar side appeared to place the amount of available surface contaminants near the limiting sensitivity of the sample array. Mass spectroscopy on the trace contaminants show the presence of high molecular weight species, up to 773 amu. The data suggests the presence of condensed aromatics.
Muscari, J. A.↗
The sublimation kinetics of GeSe single crystals
The sublimation kinetics of (001) oriented GeSe single crystal platelets was studied by high-temperature mass spectroscopy, quantitative vacuum microbalance techniques, and hot stage optical microscopy. For a mean experimental temperature of 563 K, the activation enthalpy and entropy are found to equal 32.3 kcal/mole and 19.1 eu, respectively. The vaporization coefficient is less than unity for the range of test temperatures, and decreases with increasing temperature. The combined experimental data are correlated by means of a multistep surface adsorption mechanism.
Irene, E. A.↗
Photoionization and ion cyclotron resonance studies of the ion chemistry of ethylene oxide
The formation of the ethylene oxide molecular ion and its subsequent ion-molecule reactions leading to the products C2H5O(+) and C3H5O(+) have been studied using time-resolved photoionization mass spectroscopy, ion cyclotron resonance spectroscopy, and photoelectron spectroscopy. An examination of the effects of internal energy on reactivity shows that the ratio of C3H5O(+) to C2H5O(+) increases by an order of magnitude with a single quantum of vibrational energy. The formation of (C2H4O/+/)-asterisk in a collision-induced isomerization is found which yields a ring-opened structure by C-C bond cleavage. The relaxed ring-opened C2H4O(+) ion reacts with neutral ethylene oxide by CH2(+) transfer to yield an intermediate product ion C3H6O(+) which gives C3H5O(+) by loss of H.
Corderman, R. R.↗
A photoionization study of the charge transfer reactions - Xe/+/ + O2 yields O2/+/ + Xe and O2/+/ + Xe yields Xe/+/ + O2
The charge transfer reactions: Xe(+) + O2 yields O2(+) + Xe and O2(+) + Xe yields Xe(+) + O2 were studied using photoionization mass spectroscopy. It is shown that the reaction of Xe(+)(2P-3/2) ions with O2 molecules is much more efficient than the reaction of Xe(+)(2P-1/2) ions with O2 molecules. The charge transfer reaction of O2(+) ions with Xe atoms was detected for O2(+) ions in the a 4Pi-u state.
Ajello, J. M.↗
Removal of contaminant gases from an electrolytic urine pretreatment process
The effluent gas stream from an electrolytic urine pretreatment process was analyzed by gas chromatography-mass spectroscopy and wet chemical methods to determine its composition. The major constituents were identified as: hydrogen, carbon dioxide, oxygen, nitrogen, water vapor, and chlorine. The trace impurities were chlorinated light hydrocarbons, and a number of other organic impurities in the low ppm range. Several methods of removing all of the undesirable gases to levels acceptable for return to a space cabin atmosphere were investigated experimentally. A subsystem concept comprised of the following sequential unit processes and operations was successfully demonstrated: (1) raw urine scrubbing, (2) silica gel sorption, (3) dilution with cabin air, and (4) catalytic oxidation.
Colombo, G. V.↗