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At least 1,477 records · Page 82
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Rotor burst protection program: Statistics on aircraft gas turbine engine failures that occurred in commercial aviation during 1971

A program to develop criteria for the design of devices that will be used on aircraft to protect passengers and the aircraft structure from the lethal and devastating fragments generated by the disintegration of a gas turbine engine rotor is discussed. Statistics on gas rotor turbine failures that have occurred in commercial aviation in 1971 are presented. It is shown that 124 rotor failures occurred and 35 of these were uncontained. This figure is considered significantly high to justify continuation of the development program.

Delucia, R. A.↗
NASA NTRS1973

Physical and dynamical studies of meteors

Interplanetary distributions from a sample of 20,000 radar meteor observations are presented. These distributions are freed from all known selection effects with the exception of a possible bias against fragmenting meteors which has not yet been adequately assessed. These data thus represent the largest and most accurate collection of radar meteor distributions. Both general average distribution and the distribution of meteor streams with their comet and asteroid associations are presented. Sporadic space density and space density of meteor streams are also included.

Southworth, R. B.↗
NASA NTRS1973

Martian surface coordinates

Methods and results are presented for primary and secondary triangulation of the Martian surface. The primary network is based on multiphotograph stereophotogrammetry in which the pictures are rotated around fixed centers; these centers are provided as spacecraft stations from the tracking data. The computations use the latest Mars spin axis determined by Mariner 9 experiments and the new first meridian passing through a small crater, Airy-O, seen on Mariner 9 imagery. The secondary triangulation is performed in the map plane using rectified pictures as map fragments, assumed to be of correct shape. Primary positions are given.

Davies, M. E.↗
NASA NTRS1973

The atomic nature of polymer-metal interactions in adhesion, friction and wear

Adhesion experiments with polytetra-fluoroethylene (PTFE) and polyimide contacting tungsten indicate that the polymers bond chemically to the clean metal surface. Polymer chain fragments which transfer to the surface of tungsten in field ion microscopy adhesion studies are highly oriented. Auger emission spectroscopy of PTFE transfer films to various metal surfaces indicates that the PTFE is bonded to the metal surface via the carbon atom. With PTFE in sliding contact with different orientations of aluminum, metal orientation is found to influence surfaces in sliding. The lowest friction and least amount of surface damage is detected on the highest atomic density (111) plane. The friction process itself can initiate polymer film formation from simple organic molecules.

Buckley, D. H.↗
NASA NTRS1972

Mass spectrometry.

Review of the current state of mass spectrometry, indicating its unique importance for advanced scientific research. Mass spectrometry applications in computer techniques, gas chromatography, ion cyclotron resonance, molecular fragmentation and ionization, and isotope labeling are covered. Details are given on mass spectrometry applications in bio-organic chemistry and biomedical research. As the subjects of these applications are indicated alkaloids, carbohydrates, lipids, terpenes, quinones, nucleic acid components, peptides, antibiotics, and human and animal metabolisms. Particular attention is given to the mass spectra of organo-inorganic compounds, inorganic mass spectrometry, surface phenomena such as secondary ion and electron emission, and elemental and isotope analysis. Further topics include mass spectrometry in organic geochemistry, applications in geochronology and cosmochemistry, and organic mass spectrometry.

Burlingame, A. L.↗
NASA NTRS1972

Petrographic and electron microprobe study of the Monturaqui impactite.

Study of Monturaqui-crater impactite specimens attempting to determine the type of shock features present, shock intensities, type of meteorite projectile, and environmental conditions of impactite formation, by means of petrographic and electron microprobe techniques. The specimens were found to contain shocked and unshocked mineral and rock fragments together with Ni-Fe-Co-P spherules tightly bound in a partly devitrified matrix of clear, green or brown glass. Shock effects range from lightly shocked to intensely shocked. Observed and simulated shock effects are discussed.

Bunch, T. E.↗
NASA NTRS1972

The particle track record of the lunar surface.

Information about lunar surface history revealed by fossil particle tracks is summarized. Such tracks are the result of damage left in dielectric materials by highly ionizing charged particles including heavy solar and galactic cosmic ray nuclei, heavy nuclei recoiling from cosmic ray induced spallation reactions, and induced- and spontaneous-fission fragments. From the distribution of cosmic ray and spallation tracks in the lunar rock, surface residence times of 1 to 30 million years and rock erosion rates of 1 to 10 A/yr have been determined. Particle tracks also record surface orientation and depth history of the rocks and contain information about ancient solar activity.

Comstock, G. M.↗
NASA NTRS1973

Apollo 16 exploration of Descartes - A geologic summary.

The Cayley Plains at the Apollo 16 landing site consist of crudely stratified breccias to a depth of at least 200 meters, overlain by a regolith 10 to 15 meters thick. Samples, photographs, and observations by the astronauts indicate that most of the rocks are impact breccias derived from an anorthosite-gabbro complex. The least brecciated members of the suite include coarse-grained anorthosite and finer-grained, more mafic rocks, some with igneous and some with metamorphic textures. Much of the transverse area is covered by ejecta from North Ray and South Ray craters, but the abundance of rock fragments increases to the south toward the younger South Ray crater.

Source record↗
NASA NTRS1973

Spinel troctolite and anorthosite in Apollo 16 samples.

Review of the examination results on two Apollo 16 rocks recovered from the lunar highlands which probably represent contrasting types of 'primitive' lunar cumulates. One is a microbreccia containing a large lithic fragment of spinel troctolite, while the other is a shock-brecciated anorthosite. The reviewed results suggest that, if the two rock groups formed from the same parent magma type, the spinel troctolite must have formed early in the differentiation sequence as the result of crystal settling in the melt, whereas the anorthosite must have formed as a later cumulate, possibly by flotation.

Prinz, M.↗
NASA NTRS1972

Mariner 9 television observations of Phobos and Deimos.

Mariner 9 photographs of Phobos and Deimos have yielded new information about the orbits, rotation periods, sizes, shapes, and surface characteristics of the satellites. Both satellites appear to be in synchronous rotation. They are irregular, heavily cratered bodies whose shapes appear to have been determined largely by impact fragmentation and spalling. The surfaces of both satellites have crater densities close to saturation and nearly identical, very low albedos. Lower limits on the tensile and yield strengths are estimated, and it is concluded that both satellites may consist of well-consolidated, though possibly highly fractured material.

Pollack, J. B.↗
NASA NTRS1972

Pyroxenes from breccia 14303.

Review of the investigation results obtained on the adjacent polished thin sections 47 and 53 of breccia 14303, the largest rock returned by Apollo 14 for which a location has not been established. A basaltic lithic clast, composed mainly of plagioclase, olivine, and pigeonite zoned to subcalcic augite, is found to occupy the same relative position in both sections and is assumed to represent a single lithic chip. Further study of lithic and fragmental clasts in breccias is seen likely to yield information on lunar history between 4.6 and 3.9 b.y. ago.

Weigand, P. W.↗
NASA NTRS1972

Distinct subsolidus cooling histories of Apollo 14 basalts.

Study of the distribution of magnesium and ferrous iron over the M1 and M2 positions in pyroxenes from the basaltic rocks 14053 and 14310, aimed at an analysis of the subsolidus cooling history. The results obtained suggest that the subsolidus cooling of the basalt 14310 occurred at a depth of several meters in a coherent body of appreciable size. As for the 14053, the hot debris of which it was a part were deposited after the projection from the Imbrium basin; some smaller fragments, including 14503, cooled very rapidly in the cold Fra Mauro regolith by conduction.

Schurmann, K.↗
NASA NTRS1972

Compositional characteristics of some Apollo 14 clastic materials.

Eighty-two subsamples of Apollo 14 materials have been analyzed by instrumental neutron activation analysis techniques for as many as 25 elements. In many cases, it was necessary to develop new procedures to allow analyses of small specimens. Compositional relationships among Apollo 14 materials indicate that there are small but systematic differences between regolith from the valley terrain and that from Cone Crater ejecta. Fragments from 1-2 mm size fractions of regolith samples may be divided into compositional classes, and the 'soil breccias' among them are very similar to valley soils. Multicomponent linear mixing models have been used as interpretive tools in dealing with data on regolith fractions and subsamples from breccia 14321. These mixing models show systematic compositional variations with inferred age for Apollo 14 clastic materials.

Lindstrom, M. M.↗
NASA NTRS1972

Rb-Sr systematics for chemically defined Apollo 14 breccias.

The Rb and Sr systematics were determined for eight lithic fragments from the coarse fines of Apollo 11, Apollo 12, and Apollo 14; for bulk soils from Luna 16, Apollo 14, and Apollo 15 and for 'whole rocks' from Apollo 14 and the Apollo 15 anorthosite 15415. The objective of the studies was to identify important lunar rock types by their major and trace element chemistry and utilize Rb and Sr systematics to obtain a chronology for events which establish or modify rock chemical composition.

Nyquist, L. E.↗
NASA NTRS1972

The ages of lunar material from Fra Mauro, Hadley Rille, and Spur Crater.

Ar-40/Ar-39 dating techniques were applied to estimate the age of twelve crystalline and fragmented Fra Mauro rock samples and six Hadley Rille and Spur Crater rock samples provided by the Apollo 14 and 15 missions. Genesis histories of some associated lunar surface features are traced back on the basis of obtained rock age values.

Husain, L.↗
NASA NTRS1972

Cosmogenic nuclides in football-sized rocks.

The activity of long- and short-lived isotopes in a series of samples from a vertical column through the center of rock 14321 was measured. Rock 14321 is a 9 kg fragmental rock whose orientation was photographically documented on the lunar surface. Also investigated was a sample from the lower portion of rock 14310, where, in order to study target effects, two different density fractions (mineral separates) were analyzed. A few nuclides in a sample from the comprehensive fines 14259 were measured. This material has been collected largely from the top centimeter of the lunar soil. The study of the deep samples of 14321 and 14310 provided values for the activity of isotopes at points where only effects produced by galactic cosmic rays are significant.

Wahlen, M.↗
NASA NTRS1972

Exposure ages and neutron capture record in lunar samples from Fra Mauro.

Cosmic-ray exposure ages of Apollo 14 rocks and rock fragments obtained by the Kr81-Kr83 method range from 27 to 700 m.y. Rock 14321, collected near the Cone crater rim, is one of the many approximately 27 m.y. old ejecta which were reported at the Third Lunar Science Conference. All the other rocks have considerably higher exposure ages. Isotopic anomalies from neutron capture in gadolinium, bromine, and barium are used to obtain information on the lunar neutron spectrum at various depths below the lunar surface. The flux ratio of resonance and slow (less than 0.3 eV) neutrons is found to be nearly constant in the topmost approximately 100 g/sq cm.

Lugmair, G. W.↗
NASA NTRS1972

Magnetic phases in lunar material and their electron magnetic resonance spectra - Apollo 14.

Electron magnetic resonance spectra of soil samples 14163,68, 14148,31, 14149,47, 14156,31, and 14003,60, and of fragmental rocks 14301,66, 14303,42, 14310,68, 14311,36, 14318,36, and 14321,166 have been recorded at 9 and 35 GHz at 300 K and at 9 GHz at 130 K. One spectral component, the characteristic ferromagnetic resonance, of all the soil samples is 50 to 1000 times more intense than any other component in the soils or in the spectra of the rocks. The intensity of this component in Apollo 11, Apollo 12, and Apollo 14 soils varies only within one order of magnitude. It varies with depth below lunar surface but is not correlated with depth. The intensity does not have any correlation with the fraction of glassy particles nor with the fraction of anorthositic particles.

Weeks, R. A.↗