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At least 829 records · Page 46
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Sampling nitric oxide from combustion gases.

Experimental study of several sampling tube and probe material compositions and designs aimed at preventing nitric oxide reduction when sampling nitric oxide from combustion gases. A 250,000 Btu/h furnace fired with technical grade methane was used for testing the sampling probes over a wide range of air-fuel mixtures. The results obtained include the finding that the use of stainless steel in probes creates inaccuracies in near-stoichiometric and fuel-rich sampling in hydrocarbon flames. For very fuel-rich flames, water cooling is needed even in quartz probes to prevent significant reduction of nitric oxide.-

England, C.↗
NASA NTRS1973

Development study of the X-ray scattering properties of a group of optically polished flat samples

A group of twelve optically polished flat samples were used to study the scattering of X-rays. The X-ray beam reflected from the twelve optical flat samples was analyzed by means of a long vacuum system of special design for these tests. The scattering measurements were made at 8.34A and 0.92 deg angle of incidence. The results for ten of the samples are comparable, the two exceptions being the fire polished samples.

Froechtenigt, J. F.↗
NASA NTRS1974

Electrophoretic sample insertion

Two conductive screens located in the flow path of an electrophoresis sample separation apparatus are charged electrically. The sample is introduced between the screens, and the charge is sufficient to disperse and hold the samples across the screens. When the charge is terminated, the samples are uniformly distributed in the flow path. Additionally, a first separation by charged properties has been accomplished.

Mccreight, L. R.↗
NASA NTRS1974

Hydrogen and fluorine in the surfaces of lunar samples

The resonant nuclear reaction F-19 (p, alpha gamma)0-16 has been used to perform depth sensitive analyses for both fluorine and hydrogen in lunar samples. The resonance at 0.83 MeV (center-of-mass) in this reaction has been applied to the measurement of the distribution of trapped solar protons in lunar samples to depths of about 1/2 micrometer. These results are interpreted in terms of terrestrial H2O surface contamination and a redistribution of the implanted solar H which has been influenced by heavy radiation damage in the surface region. Results are also presented for an experiment to test the penetration of H2O into laboratory glass samples which have been irradiated with 0-16 to simulate the radiation damaged surfaces of lunar glasses. Fluorine determinations have been performed in a 1 pm surface layer on lunar samples using the same F-19 alpha gamma)0-16 resonance. The data are discussed from the standpoint of lunar fluorine and Teflon contamination.

Leich, D. A.↗
NASA NTRS1973

Evaluation of ground characterization samples MCN-2 and MCN-3, section 1

A detailed metallurgical evaluation of two exothermically brazed nickel ground characterization samples was conducted. Samples MCN-2 and MCN-3 were among six samples that were brazed as part of a exothermic brazing experiment to obtain baseline data for use in determining the effect of weightlessness on: (1) the wetting and flow behavior of brazing filler metals; and (2) the metallurgical characteristics of the brazed joints. The samples were evaluated by metallographic examination and electron microprobe analysis.

Source record↗
NASA NTRS1973

Environmental control of lunar samples in the Lunar Receiving Laboratory

The contamination controls used in the Lunar Receiving Laboratory during the processing of lunar samples are described. Initially, the lunar sample containers were opened and the material was examined in a vacuum complex with approximated lunar surface conditions. The process of examining and distributing the samples from this vacuum complex was time consuming. During both Apollo 11 and 12 missions portions of the lunar samples were processed for allocation in a small sterile glove box in a dry nitrogena atmosphere. After Apollo 12 a new system was installed based upon the experience gained from the small glove box. The system uses dry nitrogen as an environmental blanket and has the capability of being sterilized and of maintaining this sterility.

Reynolds, M. A.↗
NASA NTRS1973

Techniques for the analysis of gases sequentially released from lunar samples

Description of two methods for the analysis of light gases that are sequentially evolved from 2 to 10 mg of lunar sample. A hydrofluoric acid hydrolysis of lunar material is achieved by repeated exposure of the sample to hydrogen fluoride. In the second technique, gases are evolved from lunar samples by the stepwise heating of these samples to 1400 C. The gases evolved by either hydrolysis or pyrolysis are analyzed in a gas chromatographic system using a helium ionization detector. The sensitivities of this detector for the gases, as analyzed, range from 20 picograms/sec for hydrogen to 0.2 picogram/sec for carbon dioxide.

Desmarais, D. J.↗
NASA NTRS1973

Major and trace element abundances in samples from the lunar highlands

Analyses for major elements, REE, Co, Cr, Cs, Ga, Hf, Ni, Rb, Sc, and Zn have been done on samples of Apollo 16 rocks 60025, 60335, 64455, 65015, 67075, and 67629 and on fines 60601, 61221, 61241, 64501, 65701, 67601, and 69941. FeO, Na2O, REE, Co, Cr, Hf, and Sc have been determined in four 4-5 mg chips from 65015 and 20 individual, 2.5-9.5 mg fragments from 65702. It appears that trace element characteristics of small fragments are similar to those of larger rocks. No simple mixing relationship was found among KREEP basalts, VHA basalts, anorthosites, fines, and meteorites. Balances could not be simultaneously achieved for Al2O3 and LIL elements, using analyzed samples as end members for mixing models. Most samples analyzed have negative Eu anomalies, in contrast to the positive anomalies expected for plagioclase cumulates. Most samples may be derived from LIL-rich liquids that flowed into highland valleys.

Haskin, L. A.↗
NASA NTRS1973

Solar wind and terrestrial atmosphere effects on lunar sample surface composition

Samples returned from the Apollo missions have been shown to have undergone a partial surface oxidation with the degree of oxidation being dependent on the intensity and duration of exposure to a terrestrial or other oxidizing atmosphere. Exposure to atomic hydrogen at room temperature, or molecular hydrogen above 100 C results in a surface reduction. The adsorption of water vapor on a test sample was found to be only slightly dependent on the state of surface oxidation, a situation consistent with the formation of hydroxyl groups on the surface when a sample is exposed to hydrogen. That hydroxyl groups are indeed formed is substantiated by the release of water vapor (and by release of heavy water following exposure to deuterium), indicating that water vapor can be synthesized from solar wind hydrogen and sample oxygen. Observations of trace amounts of methane indicate that the reduction process is by no means restricted to the formation of water vapor.

Cadenhead, D. A.↗
NASA NTRS1973

Dielectric spectra of Apollo 15 and 16 lunar solid samples

Description of the dielectric constants, losses, and ac-conductivities of lunar samples 15065,27, 15459,62, 15555,88, 15415,57, 60015,29, 60315,34, 61016,34, and 62235,17 as measured over a range of frequencies from 100 Hz to 10 MHz and temperatures from 77 to 473 K by two-terminal capacitance substitution methods. The dielectric spectra of lunar gabbroic basalts are typified by the dielectric behavior of samples 15065 and 15555, showing complex relaxation processes which are both frequency- and temperature-dependent. Such feldspar-rich crystalline lunar basalts like samples 15459, 62235, and 60015 showed essentially the same dielectric relaxation mechanisms which are also a function of both frequency and temperature with a very broad relaxation frequency distribution. Highly-brecciated lunar sample, 60315, exhibits rather an unusual dielectric behavior which is dependent upon on field-strength.

Chung, D. H.↗
NASA NTRS1974

Gamma-spectrometric analysis of Luna 16 sample of lunar surface material

Using a scintillation gamma spectrometer with shielding against anticoincidences, the content of the natural radioelements (K, U, and Th) and long-lived cosmogenic radioisotopes (Al-26, Na-22, and Mn-54) in a sample of Sea of Fertility regolith was determined. Based on the content data of natural radioelements, an attempt was made to classify this sample in the scale of petrochemical types of terrestrial rocks arranged in accordance with their silicic content and alkalinity. Within the frame of reference of calcium-uranium systematics of lunar samples, a comparison was made of the K/U ratio obtained for the Sea of Fertility sample with analogous data for other regions of the moon. Also discussed are problems on the depthwise distribution of cosmogenic radioisotopes along the regolith profile.

Surkov, Y. A.↗
NASA NTRS1974

Study of radiation damage and structure of Luna 16 sample particles using high-resolution electron microscopes

Using an electron scanning microscope and a high voltage microscope, a study was made of the radiation damage and structure of micron sized grains and grains separated from the 200-mesh fraction of the L-16-19 surface material sample. Then the structural features were compared with those found by studying with the same techniques grains separated from 20 different samples of lunar dust taken from the Apollo 11, Apollo 12, Apollo 14, and Apollo 15 collections. The L-16-19 sample is similar to the most intensely irradiated samples returned to earth by Apollo craft.

Borg, J.↗
NASA NTRS1974

Short guide to lunar sample information

Data pertaining to the collection, processing, and study of lunar samples, and the ways to gain access to that data are described. Data pertaining to the samples includes not only the normally published literature but also NASA and USGS interagency documents, sample processing information, and photography taken from lunar orbit, on the lunar surface, and of samples in the Lunar Receiving Laboratory.

Simonds, C. H.↗
NASA NTRS1975

Nuclear chemistry of returned lunar samples: Nuclide analysis by gamma-ray spectrometry

Primordial and cosmogenic radionuclide concentrations are determined nondestructively by gamma-ray spectrometry in soil and rock samples from the returned Apollo 17 sample collection from Taurus-Littrow and Descartes. Geochemical evidence in support of field geology speculation concerning layering of the subfloor basalt flows is demonstrated along with a possible correlation of magmatic fractionation of K/U as a function of depth. The pattern of radionuclide concentrations observed in these samples is distinct due to proton bombardment by the intense solar flares of August 4-9, 1972. Such radionuclide determinations are used in determining lunar sample orientation and characterizing solar flare activity.

Okelley, G. D.↗
NASA NTRS1975

An automated atmospheric sampling system operating on 747 airliners

An air sampling system that automatically measures the temporal and spatial distribution of selected particulate and gaseous constituents of the atmosphere has been installed on a number of commercial airliners and is collecting data on commercial air routes covering the world. Measurements of constituents related to aircraft engine emissions and other pollutants are made in the upper troposphere and lower stratosphere (6 to 12 km) in support of the Global Air Sampling Program (GASP). Aircraft operated by different airlines sample air at latitudes from the Arctic to Australia. This system includes specialized instrumentation for measuring carbon monoxide, ozone, water vapor, and particulates, a special air inlet probe for sampling outside air, a computerized automatic control, and a data acquisition system. Air constituents and related flight data are tape recorded in flight for later computer processing on the ground.

Perkins, P.↗
NASA NTRS1974

On the petrological, geochemical, and geophysical characterization of a returned Mars surface sample and the impact of biological sterilization on the analyses

A study was conducted: to identify those experiments that could and should be done on a returned Martian sample in order to characterize its inorganic properties; to evaluate, insofar as can be done, the effects of potential biological sterilization of the sample by heating prior to its return; to identify particular analytical techniques needing further improvement in order to make optimum use of a returned sample; and to identify experiments to be done on simulants, with and without sterilization, that better define the limits of information available about the planet from analyses of returned samples.

Source record↗
NASA NTRS1975

Mars sample return through parking orbit

A Mars surface sample return mission using Mars direct entry and Mars parking orbit return is described. The mission is designed for a minimum energy requirement and is relatively simple in comparison to the alternative Mars orbital rendezvous mode. The design calls for minimal science, and uses a single Titan IIIE/Centaur launch vehicle. The primary science areas included are biology, biochemistry, geochemistry, and petrology, for detecting life, age dating, and determining chemical compositions and rock types. The total minimum sample requirement would be 30 g. Sampling conditions and recommended measurements are discussed. Maximum use of hardware and experience from the Mariner, Pioneer, and Viking missions is contemplated. The profile for a 1979 conjunction-class mission would include a total time of 1025 days, including one year in Mars parking orbit after sampling. The lander structure, components, and recovery alternatives are explained.

Weaver, W. L.↗
NASA NTRS1974

Ion microprobe mass analysis of plagioclase from 'non-mare' lunar samples

The ion microprobe was used to measure the composition and distribution of trace elements in lunar plagioclase, and these analyses are used as criteria in determining the possible origins of some nonmare lunar samples. The Apollo 16 samples with metaclastic texture and high-bulk trace-element contents contain plagioclase clasts with extremely low trace-element contents. These plagioclase inclusions represent unequilibrated relicts of anorthositic, noritic, or troctolitic rocks that have been intermixed as a rock flour into the KREEP-rich matrix of these samples. All of the plagioclase-rich inclusions which were analyzed in the KREEP-rich Apollo 14 breccias were found to be rich in trace elements. This does not seem to be consistent with the interpretation that the Apollo 14 samples represent a pre-Imbrium regolith, because such an ancient regolith should have contained many plagioclase clasts with low trace-element contents more typical of plagioclase from the pre-Imbrium crust. Ion-microprobe analyses for Ba and Sr in large plagioclase phenocrysts in 14310 and 68415 are consistent with the bulk compositions of these rocks and with the known distribution coefficients for these elements. The distribution coefficient for Li (basaltic liquid/plagioclase) was measured to be about 2.

Meyer, C., Jr.↗