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At least 1,441 records · Page 80
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NASA NTRS1972

Luminescence analysis of lunar samples returned by Apollo: Luminescence of Apollo 14 and Apollo 15 lunar samples

Luminescence measurements were made of Apollo 14 lunar samples with far UV X-ray, and proton irradiation and of Apollo 15 lunar samples with X-ray irradiation. Preliminary efficiencies with the far UV are in the range 0.001 to 0.01; efficiencies with X-rays and protons are in the range 10 to the -8th to 10 to the -6th powers. The crystalline igneous rocks show higher efficiencies, in general, than the breccias and glasses, and the ratio of intensity of the green to the blue luminescence peak tends to be higher for the crystalline igneous rocks than for breccias and glasses. Therefore, both the efficiency and the spectral character appear to have a systematic relationship to lithologic type (granitic versus gabbroic versus fragmental) and to geologic history and processes on the moon (shocked versus unshocked or only mildly shocked material).

Greenman, N. N.↗
NASA NTRS1972

The management of technology assessment

The total problem concept of technology assessment, involving a comprehensive information management activity with an objective orientation to the assessment function is discussed. A brief overview of the technology assessment function and some past experiences are given. Fragmentation of assessment systems, optimum social subsystem for examination in particular assessments, and adequacy of assessments are studied. The magnitude of the technology assessment function and the level of support required for the effective performance of this function are also discussed. One type of institutional arrangement which might produce a close approximation to the total problem assessment approach is suggested.

Mayo, L. H.↗
NASA NTRS1972

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

Concentrations of primordial radioelements and of cosmogenic radionuclides in crystalline rocks, breccias, and soils from the Ocean of Storms were determined. Concentrations of K, Th, U, Al-26, and Na-22 were determined for seven clastic or brecciated rocks, three sieved samples of fines, and one composite sample of sawdust from the cutting of a fragmental rock, all from samples obtained on the Apollo 14 mission. The K, Th, and U concentrations and cogmogenic radionuclide abundances in rocks and soils from Apollo 15 are also discussed.

Kelley, G. D.↗
NASA NTRS1972

Ultraviolet atomic emission detector

A device and method are provided for performing qualitative and quantitative elemental analysis through the utilization of a vacuum UV chromatographic detector. The method involves the use of a carrier gas at low pressure. The gas carries a sample to a gas chromatograph column; the column output is directed to a microwave cavity. In this cavity, a low pressure microwave discharge produces fragmentation of the compounds present and generates intense atomic emissions in the vacuum ultraviolet. These emissions are isolated by a monochromator and measured by photometer to establish absolute concentration for the elements.

Braun, W.↗
NASA NTRS1972

Cracking of the lunar soil

Rather than a pattern of cracks in an apparently flat surface, the Apollo 12 photographs suggest an irregular surface that consists of clods or fragments. The impression of flat tiles and crusting, obtained by monoscopic viewing, is an illusion. Instead, the lunar soil deforms and cracks in the same manner as homogeneous isotropic terrestrial soils of moderate bulk density, having a small amount of cohesion.

Jaffe, L. D.↗
NASA NTRS1972

Adhesion and transfer of PTFE to metals studied by auger emission spectroscopy

The adhesion and transfer of polytetrafluoroethylene (PTFE) to metals in ultrahigh vacuum has been studied using Auger emission spectroscopy. The transfer was effected both by compressive static contact and by sliding contact. The transfer observed after static contact was independent of the chemical constitution of the substrate. Electron induced desorption of the fluorine in the transferred PTFE showed that the fluorine had no chemical interaction with the metal substrate. The coefficient of friction on metals was independent of the chemical constitution of the substrate. However, sliding PTFE on soft metals such as aluminum, generated wear fragments that lodged in the PTFE and machined the substrate.

Pepper, S. V.↗
NASA NTRS1972

Beryllium particle combustion

A two-year study of the combustion efficiency of single beryllium droplets burning in a variety of oxidizers (primarily mixtures of oxygen/argon and oxygen/nitrogen) is summarized. An advanced laser heating technique was used to acquire systematic quantitative data on the burning of single beryllium droplets at atmospheric pressure. The research confirmed the sensitivity of beryllium droplet combustion to the chemistry of environmental species and provides experimental documentation for the nitrogen-induced droplet fragmentation of burning beryllium droplets.

Prentice, J. L.↗
NASA NTRS1972

Adhesion and transfer of polytetrafluorethylene to metals studied by Auger emission spectroscopy

The adhesion and transfer of polytetrafluoroethylene (PTFE) to metals in ultrahigh vacuum were studied. The transfer was effected both by compressive static contact and by sliding contact. The transfer observed after static contact was independent of the chemical constitution of the substrate. Electron-induced desorption of the fluorine in the transferred PTFE showed that the fluorine had no chemical interaction with the metal substrate. The coefficient of friction on metals was independent of the chemical constitution of the substrate. However, sliding PTFE on soft metals, such as aluminum, generated wear fragments that lodged in the PTFE and machined the substrate.

Pepper, S. V.↗
NASA NTRS1972

Study of dense aluminum plasmas

Studies directed toward the development of a computer program describing the penetration of a thin aluminum plate by a quartz sphere are reported. The aluminum simulates a bumper plate for micrometeoroids. The ablation of a rock sphere by penetrating a stack of paper sheets is described, and an equation for losses near the surface of the sphere is derived. The expansions of aluminum plasma sphere with initial energies of 44.45, 20.8, and 7.136 eV are investigated, including shock compression during penetration and adiabatic expansion. The equations of state were derived for aluminum and quartz, as well as one of the Mie-Grunesen type. A technique to determine momentum at the bottom surface of the thin plate, and the energy for hypervelocity separation of fragments of the aluminum plate are also considered.

Todd, F. C.↗
NASA NTRS1971

Ballistic piston fissioning plasma experiment.

The production of fissioning uranium plasma samples such that the fission fragment stopping distance is less than the dimensions of the plasma is approached by using a ballistic piston device for the compression of uranium hexafluoride. The experimental apparatus is described. At room temperature the gun can be loaded up to 100 torr UF6 partial pressure, but at compression a thousand fold increase of pressure can be obtained at a particle density on the order of 10 to the 19th power per cu cm. Limited spectral studies of UF6 were performed while obtaining the pressure-volume data. The results obtained and their implications are discussed.

Miller, B. E.↗
NASA NTRS1971

Midday auroral observations in the oval, cusp region, and polar cap.

Evaluation of combined photographic and photometric measurements made on the 1969 NASA airborne expedition, yielding a description of the midday oval, cusp region, and polar cap auroral precipitation at low magnetic activity (Kp = 0, 1+). The observations delineate three regions through the description of the type of aurora observed and the photometrically inferred change in energy of the particles: (1) the region in and equatorward of the oval where greater than 3-keV electrons are associated with 6300 A/4278 A ratios less than or equal to 1 and with a diffuse glow or structured arcs; (2) the cusp region where electrons of several hundred electron volts and spikes of more energetic electrons are associated with 6300 A/4278 A ratios between 10 and 35 in broken, fragmented, rayed features and patches; (3) the polar cap where discrete earth-sun-aligned arcs have height luminosity profiles in 5577 A, 6300 A (forbidden O I), and 4278 A (N2(+)) that suggest incoming electrons with an energy spectrum of 2-keV characteristic energy above a low-energy (few hundred electron volts) background.

Romick, G. J.↗
NASA NTRS1971

Sedimentology of Apollo 11 and 12 lunar soils.

Differences in the modal composition of samples from an Apollo 11 core tube (10005) suggest the presence of at least three depositional units. The double-drive-tube core sample from the Apollo 12 site shows evidence of at least 16 depositional episodes. The earliest recognizable event at the Apollo 12 site carried light-colored soil rich in feldspathic-rock fragments into the area and may be related to ejection of ray material from Copernicus. Prior to the formation of Surveyor Crater at least 11 depositional episodes took place. Unit 7-8, the thickest unit intersected by the core tube, is tentatively identified as the Surveyor Crater ejecta blanket. Most of the soil at the Apollo 11 and 12 sites was probably generated locally with a smaller contribution coming from a more distant source possibly in the lunar highlands.

Lindsay, J. F.↗
NASA NTRS1971

Parathyroid hormone - Secretion and metabolism in vivo.

Gel filtration and radioimmunoassay were used to determine the molecular size and immunochemical reactivity of parathyroid hormone present in gland extracts, in the general peripheral circulation, and in parathyroid effluent blood from patients with hyperparathyroidism, as well as from calves and from cattle. It was found that parathyroid hormone secreted from the parathyroids in man and cattle is at least as large as the molecule extracted from normal bovine glands. However, once secreted into the circulation the hormone is cleaved, and one or more fragments, immunologically, dissimilar to the originally secreted hormone, constitute the dominant form of circulating immunoreactive hormone.

Habener, J. F.↗
NASA NTRS1972

Quenching of the B /super 2/Sigma-plus state of the CN radical.

The quenching of the B (super 2)Sigma-plus fluorescence from the CN radical has been studied as a function of the relative velocity of the quenching collision and the total pressure in the fluorescence cell. The rate constant for the quenching of the CN fragment by ICN vapor was found to be directly proportional to the relative velocity of the quenching collision. Electronic quenching was also observed for methane, diatomic hydrogen, Kr, and Ar.

Jackson, W. M.↗
NASA NTRS1972

Moon - Possible nature of the body that produced the Imbrian Basin, from the composition of Apollo 14 samples.

Soils from the Apollo 14 site contain nearly three times as much meteoritic material as soils from the Apollo 11, Apollo 12, and Luna 16 sites. Part of this material consists of the ubiquitous micrometeorite component, of primitive (carbonaceous-chondrite-like) composition. The remainder, seen most conspicuously in coarse glass and norite fragments, has a decidedly fractionated composition, with volatile elements less than one-tenth as abundant as siderophiles. This material seems to be debris of the Cyprus-sized planetesimal that produced the Imbrian Basin. Compositionally this planetesimal has no exact counterpart among known meteorite classes, though group IVA irons come close. It also resembles the initial composition of the earth as postulated by the two-component model. Apparently the Imbrian planetesimal was an earth satellite swept up by the moon during tidal recession or capture, or an asteroid deflected by Mars into terrestrial space.

Ganapathy, R.↗
NASA NTRS1972

The Apollo 15 lunar samples - A preliminary description.

Samples returned from the Apollo 15 site consist of mare basalts and breccias with a variety of premare igneous rocks. The mare basalts are from at least two different lava flows. The bulk chemical compositions and textures of these rocks confirm the previous conclusion that the lunar maria consist of a series of extrusive volcanic rocks that are rich in iron and poor in sodium. The breccias contain abundant clasts of anorthositic fragments along with clasts of basaltic rocks much richer in plagioclase than the mare basalts. These two rock types also occur as common components in soil samples from this site. The rocks and soils from both the front and mare region exhibit a variety of shock characteristics that can best be ascribed to ray material from the craters Aristillus or Autolycus.

Source record↗
NASA NTRS1972

Geologic setting of the Apollo 15 samples.

The samples and photographs returned from the Apollo 15 site show that Hadley Delta is largely underlain by breccias whose clasts are mainly fragments of coarse-grained feldspathic rocks and nonmare-type basalt. Conspicuous sets of lineaments, visible in surface and orbital photographs of Mount Hadley and Hadley Delta, may represent systematic layering or fracture sets. The mare surface, with regolith about 5 meters thick, is underlain by two major basalt types, at least one of which has extensive lateral continuity and is exposed in the upper wall of Hadley Rille. Gradual erosional recession of the edges and filing of the interior of the rille by talus have contributed to the present cross sectional profile.

Source record↗
NASA NTRS1972

Gas-retention and cosmic-ray exposure ages of lunar rock 15555.

Conclusions are presented regarding the age of formation and exposure to cosmic rays of rock 15555 (a large rock from near the rim of Hadley Rille presumed to be a fragment of the local bedrock), based on isotopic dilution K/Ar and Ar-40/Ar-39 methods. Comparisons are made with other investigators' findings, and some cases of agreement and divergence are discussed.

Podosek, F. A.↗