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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Some volcanic and structural features of Mare Serenitatis

Relationships between volcanic and structural features along the southern edge of Mare Serenitatis as determined from low angle lighting in Apollo 17 photographs are discussed. Observational summaries are given of: (1) contact relations between the dark border material and the central mare fill, (2) a late stage lava flow with associated cinder cones, and (3) certain structural features related to the development of the mare basin and its associated volcanic landforms. A chronologic summary is given of volcanic and structural events believed to be critical to understanding the development of Mare Serenitatis.

Bryan, W. B.↗
NASA NTRS1982

Structural features of conducting quasi-one-dimensional organic halides and pseudohalides

The physical properties of quasi-one-dimensional conductors are profoundly influenced by slight changes in structure. The unusual structural features of this class of materials include only short range order of the anions and structure modulation. The nature of disorder and structure modulation can affect the character of the metal-to-insulator transition at low temperature, and may allow us to make some predictions of low temperature behavior based on room temperature structural properties.

Williams, R.↗
NASA NTRS1973

Capability of ERTS-1 imagery to investigate geological and structural features in a sedimentary basin (Bassin Parisien, France)

A preliminary study of the MSS imagery of a sedimentary basin whose structure is regular is reported. Crops and natural vegetation are distributed all over the site located under temperate climate. Ground data available concern plant species geology and tectonic and are correlated with results from ERTS 1 imagery. This comparison shows a good correlation. The main geological units are detected or enhanced by way of agricultural land use and/or natural vegetation. Alluvial deposits are outlined by vegetation grass land and poplar trees. Some spatial relationship of geostructures, suspected until now, are identified or extended in associating results from different spectral bands.

Cavelier, C.↗
NASA NTRS1973

Structural features in the Colorado Plateau margin near Flagstaff, Arizona

The author has identified the following significant results. On ERTS-1 frame 1014-17375, a set of northwest-trending lineaments has been discovered which converge on the north-trending lineament of the Oak Creek Fault near Flagstaff, Arizona. The lineaments are most easily seen in band 7. The region of convergence may mark an area structurally favorable for the location of water in Paleozoic sediments that underlie the basalt cap.

Goetz, A. F. H.↗
NASA NTRS1984

Some structural features of unsteady separating turbulent shear flows

Some physical features of unsteady separating turbulent boundary layers are presented for practical Reynolds numbers and reduced frequencies for helicopter and turbomachinery flows. Upstream of detachment in moderate amplitude flows, the flow is quasi steady, i.e., the phase averaged flow is described by the steady-free stream flow structure. Results show that oscillation waveform and amplitude strongly influence the detached flow behavior.

Simpson, R. L.↗
NASA NTRS1973

Capability of ERTS-1 imagery to investigate geological and structural features in a sedimentary basin (Bassin Parisien, France)

The author has identified the following significant results. The region covered by the MSS images has the benefit of complete geological mapping at scales of 1:80,000, 1:320,000, and 1:1,000,000. Comparison of imagery and exisiting geological maps, particularly the 1:1,000,000 scale, produces important information: (1) Good correspondence is seen between large units distinguished on the images and the concentric strata of the Jurassic, Cretaceous, and Paleocene on the map. (2) Comparison of MSS images with the hydrogeological map of the Parisian basin at 1:500,000 removes all ambiguity with regard to lithological variations. Among the many faults revealed, only three were considered: (1) the Metz; (2)Juranze; and (3) the double fault of the Marne. Imagery shows a conspicuous alignment of the Metz fault unknown until now and ending near Montereau against the group of north-south faults between Montargis and Bourbon l'Archambault. MSS images show that the Juranze fault divides beyond Brienne into two branches of equal importance. The northern one represents the known fault, the southern one was not known until now, but the convergence of the faults constitutes a tectonic trap. The double fault of the Marne is known for a total length of 50 km. ERTS-1 imagery suggest a prolongation toward the southeast which could bring its length to 110 km.

Weecksteen, G.↗
NASA NTRS1974

An interpretation of volcanic and structural features of crater Aitken

Detailed observations from the study of Apollo 17 panoramic photography of the Aitken crater are reported which suggest that there has been significant late-stage compressional deformation of the crater and its adjacent highlands. A speculative interpretation of eruptive activity and drain-back events within Aitken is presented, which leads to the conclusion that hummocky topography within certain cones represents collapsed lava rather than extrusive domes. That is, eruptive activity within Aitken probably commenced with an explosive cone-building stage, followed by lava eruptions from cones and fissures, and ended with drain-back restricted to the relatively deep lava ponded in the vents.

Bryan, W. B.↗
NASA NTRS1980

Structural features of the nonionic surfactants stabilizing long-lived bubble nuclei

A study of the effects of various electrolytes and one organic compound on bubble production in agarose gels is presented. Several preparations of ultrapure agarose were compared for 42 electrolytes and phenol to identify trends in bubble formation. The anion and cation sequences of bubble suppression are similar to processes for salting out of nonionic surfactants. The reduction of bubble number by polyvalent ions and 1% phenol suggests that the polar portions of these nonionic surfactants represent amide groups. The evidence for amide groups is consistent with the relative positions of Mg(2+) in all cation sequences; this result makes it unlikely that either linkages contribute to the hydrophilicity of the nonionic surfactants stabilizing bubble nuclei in the different aqueous gels tested.

Darrigo, J. S.↗
NASA NTRS1981

Pattern, age, and origin of structural features within the Ozark plateau and the relationship to ore deposits

Topography and gravity anomaly images for the continental United States were constructed. Evidence was found based on gravity, remote sensing data, the presence, trend, and character of fractures, and on rock type data, for a Precambrian rift through Missouri. The feature is probably the failed arm of a triple junction that existed prior to formation of the granite-rhyolite terrain of southern Missouri.

Arvidson, R. E.↗
NASA NTRS2002

Atmospheric pressure chemical ionization studies of non-polar isomeric hydrocarbons using ion mobility spectrometry and mass spectrometry with different ionization techniques

The ionization pathways were determined for sets of isomeric non-polar hydrocarbons (structural isomers, cis/trans isomers) using ion mobility spectrometry and mass spectrometry with different techniques of atmospheric pressure chemical ionization to assess the influence of structural features on ion formation. Depending on the structural features, different ions were observed using mass spectrometry. Unsaturated hydrocarbons formed mostly [M - 1]+ and [(M - 1)2H]+ ions while mainly [M - 3]+ and [(M - 3)H2O]+ ions were found for saturated cis/trans isomers using photoionization and 63Ni ionization. These ionization methods and corona discharge ionization were used for ion mobility measurements of these compounds. Different ions were detected for compounds with different structural features. 63Ni ionization and photoionization provide comparable ions for every set of isomers. The product ions formed can be clearly attributed to the structures identified. However, differences in relative abundance of product ions were found. Although corona discharge ionization permits the most sensitive detection of non-polar hydrocarbons, the spectra detected are complex and differ from those obtained with 63Ni ionization and photoionization. c. 2002 American Society for Mass Spectrometry.

Non-NASA Center↗
NASA NTRS1993

Applicability of PM3 to transphosphorylation reaction path: Toward designing a minimal ribozyme

A growing body of evidence shows that RNA can catalyze many of the reactions necessary both for replication of genetic material and the possible transition into the modern protein-based world. However, contemporary ribozymes are too large to have self-assembled from a prebiotic oligonucleotide pool. Still, it is likely that the major features of the earliest ribozymes have been preserved as molecular fossils in the catalytic RNA of today. Therefore, the search for a minimal ribozyme has been aimed at finding the necessary structural features of a modern ribozyme (Beaudry and Joyce, 1990). Both a three-dimensional model and quantum chemical calculations are required to quantitatively determine the effects of structural features of the ribozyme on the reaction it catalyzes. Using this model, quantum chemical calculations must be performed to determine quantitatively the effects of structural features on catalysis. Previous studies of the reaction path have been conducted at the ab initio level, but these methods are limited to small models due to enormous computational requirements. Semiempirical methods have been applied to large systems in the past; however, the accuracy of these methods depends largely on a simple model of the ribozyme-catalyzed reaction, or hydrolysis of phosphoric acid. We find that the results are qualitatively similar to ab initio results using large basis sets. Therefore, PM3 is suitable for studying the reaction path of the ribozyme-catalyzed reaction.

Manchester, John I.↗