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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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NASA NTRS2005

Lunar and Planetary Science XXXVI, Part 22

The Lunar and Planetary Science XXXVI, Part 22 is presented. The topics include: 1) Pressure Histories from Thin and Thick Shock-induced Melt Veins in Meteorites; 2) Nano-structured Minerals as Signature of Microbial Activity; 3) The Insoluble Carbonaceous Material of CM Chondrites as Possible Source of Discrete Organics During the Asteroidal Aqueous Phase; 4) Discovery of Abundant Presolar Silicates in Subgroups of Antarctic Micrometeorites; 5) Characteristics of a Seismometer for the LUNAR-A Penetrator; 6) Heating Experiments of the HaH 262 Eucrite and Implication for the Metamorphic History of Highly Metamorphosed Eucrites; 7) Measurements of Ejecta Velocity Distribution by a High-Speed Video Camera; 8) Petrological Comparison of Mongolian Jalanash Ureilite and Twelve Antarctic Ureilites; 9) Metallographic Cooling Rate of IVA Irons Revisited; 10) Inhomogeneous Temperature Distribution in Chondrules in Shock-Wave Heating Model; 11) Subsurface Weathering of Rocks and Soils at Gusev Crater; 12) Extinct Radioactivities in the Early Solar System and the Mean Age of the Galaxy; 13) Correlation of Rock Spectra with Quantitative Morphologic Indices: Evidence for a Single Rock Type at the Mars Pathfinder Landing Site; 14) Silicon Isotopic Ratios of Presolar Grains from Supernovae; 15) Current Status and Readiness on In-Situ Exploration of Asteroid Surface by MINERVA Rover in Hayabusa Mission; 16) Long Formation Period of Single CAI: Combination of O and Mg Isotope Distribution; 17) Supra-Canonical Initial 26Al/27Al Indicate a 105 Year Residence Time for CAIs in the Solar Proto-Planetary Disk; 18) Evolution of Mercury's Obliquity; 19) First Results from the Huygens Surface Science Package; 20) Polyhedral Serpentine Grains in CM Chondrites; 21) Mountainous Units in the Martian Gusev Highland Region: Volcanic, Tectonic, or Impact Related? 22) Petrography of Lunar Meteorite MET 01210, A New Basaltic Regolith Breccia; 23) Earth-Moon Impacts at ~300 Ma and ~500 Ma Ago; 24) Chemical and Isotopic Analyses of Apollo 16 Glasses: An Integrated Approach; 25) Measuring the Surfaces on Mars; 26) Melting in Martian Snowbanks; 27) The Effect of Ni on Fe-FeS Phase Relations: Implications for the Chemistry of the Martian Core; 28) Shorelines in the Western United States as Analogs for Hypothesized Shoreline Features on Mars; 29) Al and Ti Isotopic Ratios of Presolar SiC Grains of Type Z; 30) Physicochemical Conditions of Clinopyroxene Crystallization in the Parental Bodies of Ordinary Chondrites; 31) Metamorphosed CM and CI Carbonaceous Chondrites Could be from the Breakup of the Same Earth-crossing Asteroid; 32) Aqueous Alteration and Hydrogen Generation on Parent Bodies of Unequilibrated Ordinary Chondrites: Thermodynamic Modeling for the Semarkona Composition; and 33) Preliminary Analysis of Relative Abundances of Hydrothermal Alteration Products in the C1-N10, Y6-N19, and Yax-1_863.51 Impact Melt Samples, Chicxulub Structure, Mexico

Source record↗
NASA NTRS1971

Heating of pinch devices with lasers

Pinch devices under laser heating, determining plasma density and temperature and confining magnetic field strength with thermodynamic model

Vlases, G. C.↗
NASA NTRS1974

Glass production differences for equal-diameter impact craters

A thermodynamic model of meteorite impact is used to investigate the possibility that the creation of two impact craters of the same apparent diameter may have been accompanied by dissimilar shock heating regimes. For small craters, the idea may be concisely represented by the question of which event produces more glass, a large slow meteorite or a small fast one, if the resulting craters are of the same diameter. So that the results may be most apparent, the only parameters varied in this study are meteorite size and impact velocity. Identical basaltic material is assumed for meteorite and target. For impact velocities between 10 and 70 km/sec, an available model determines the radius of a spherical meteorite which would produce a crater diameter of 20 cm.

Rehfuss, D. E.↗
NASA NTRS1975

The evolution of climate

A quantitative evaluation is made of the climatic effects of polar wandering plus continental drift in order to determine wether this mechanism alone could explain the deterioration of climate that occurred from the warmth of Mesozoic time to the ice age conditions of the late Cenozoic. By way of procedure, to investigate the effect of the changing geography of the past on climate Adem's thermodynamic model was selected. The application of the model is discussed and preliminary results are given.

Donn, W. L.↗
NASA NTRS1975

Dust in the solar nebula

The chemical and mineralogical features of the white, Ca-rich inclusions in Allende and other carbonaceous chondrites are strikingly similar to those predicted from thermodynamic models for the highest temperature condensates from the solar nebula. Many of the physical and chemical properties of the chondritic minerals may thus be quite like those of the dust in interstellar regions. The oxygen isotopic composition of meteoritic condensates suggests that they contain a component of interstellar dust that survived the birth of the solar system.

Grossman, L.↗
NASA NTRS1978

The analysis of a nonsimilar laminar boundary layer

A computer code is described which yields accurate solutions for a broad range of laminar, nonsimilar boundary layers, providing the inviscid flow field is known. The boundary layer may be subject to mass injection for perfect-gas, nonreacting flows. If no mass injection is present, the code can be used with either perfect-gas or real-gas thermodynamic models. Solutions, ranging from two-dimensional similarity solutions to solutions for the boundary layer on the Space Shuttle Orbiter during reentry conditions, have been obtained with the code. Comparisons of these solutions, and others, with solutions presented in the literature; and with solutions obtained from other codes, demonstrate the accuracy of the present code.

Stalmach, D. D.↗
NASA NTRS1982

Warm water mass formation

Seasonal heat storage, massive upwelling, and cold water advection are shown by a thermodynamic model of the interacting atmospheric and oceanic mixed layers.

Csanady, G. T.↗
NASA NTRS1983

A 4-cylinder Stirling engine computer program with dynamic energy equations

A computer program for simulating the steady state and transient performance of a four cylinder Stirling engine is presented. The thermodynamic model includes both continuity and energy equations and linear momentum terms (flow resistance). Each working space between the pistons is broken into seven control volumes. Drive dynamics and vehicle load effects are included. The model contains 70 state variables. Also included in the model are piston rod seal leakage effects. The computer program includes a model of a hydrogen supply system, from which hydrogen may be added to the system to accelerate the engine. Flow charts are provided.

Daniele, C. J.↗
NASA NTRS1985

Sea ice - Multiyear cycles and white ice

The multiyear thickness cycles represent one of the interesting features of the sea ice studies performed by Semtner (1976) and Washington et al. (1976) with simple thermodynamic models of sea ice. In the present article, a description is given of results which show that the insulating effect of snow on the surface of the sea ice is important in producing these multiyear cycles given the physics included in the model. However, when the formation of white ice is included, the cycles almost disappear. White ice is the ice which forms at the snow-ice interface when the snow layer becomes thick enough to depress the ice below the water level. Water infiltrates the snow by coming through the ice at leads and generally freezes there, forming white ice.

Ledley, T. S.↗
NASA NTRS1987

Thermal evolution of a differentiated Ganymede and implications for surface features

Thermodynamic models are developed for the processes which controlled the evolution of the surface Ganymede, an icy Jovian satellite assumed to have a rock-rich core surrounded by a water-ice mantle. Account is taken of a heat pulse which would have arisen from a Rayleigh-Taylor instability at a deep-seated liquid-solid water interface, rapid fracturing from global stresses imposed by warm ice diapiric upwelling, impacts by large meteorites, and resurfacing by ice flows (rather than core formation). Comparisons are made with existing models for the evolution of Callisto, and the difficulties in defining a mechanism which produced the groove terrain of Ganymede are discussed.

Kirk, R. L.↗
NASA NTRS1987

Relaxation of magnetotail plasmas

A quasi-thermodynamic model is presented for the relaxation of magnetotail plasmas during substorms, followed by quiet times. It is proposed that the plasma relaxes to a state of low-potential energy subject to a small number of global constraints. The constraints are exactly preserved by all ideal motions and, approximately, by a wide class of motions of the plasma undergoing magnetic reconnection. A variational principle which minimizes the free energy predicts the relaxed state. Exact, two-dimensional solutions of the relaxed state are obtained. A universal feature of the exact solutions is a chain of magnetic islands along the tail axis. Sufficient conditions for the stability of relaxed states are obtained from the second variation of the free-energy functional.

Bhattacharjee, A.↗
NASA NTRS1987

The nonlinear thermodynamics of meteors, noctilucent clouds, enhanced airglow and global atmospheric circulation

Two types of fundamental topological junctions of elements are deduced from a nonlinear thermodynamical model. Using this scheme, the possibility of a causal relation between fireballs and faint meteors as nonlinear sources on the one hand, and noctilucent clouds (NC) and Hoffmeister's enhanced airglow (EA) as complementary formative processes in the middle atmosphere and ionosphere, on the other hand, is examined. The principal role of the global atmospheric circulation in this relation is demonstrated. Such circulation in the mesosphere appears to prevent the neutral dust dissipated by fireballs from becoming an efficient agent in NLC generation. In this case, the behavior of ionized material deposited by both the bright and faint meteors is more probably controlled, as shown from the annual variation of the E sub s layer by the darkness of lunar eclipses and the global circulation of the lower thermosphere. The role of fireballs and neutral dust might be more significant as a source of EA phenomenon.

Rajchl, J.↗
NASA NTRS1988

Nonequilibrium flow computations. 1: An analysis of numerical formulations of conservation laws

Modern numerical techniques employing properties of flux Jacobian matrices are extended to general, nonequilibrium flows. Generalizations of the Beam-Warming scheme, Steger-Warming and van Leer Flux-vector splittings, and Roe's approximate Riemann solver are presented for 3-D, time-varying grids. The analysis is based on a thermodynamic model that includes the most general thermal and chemical nonequilibrium flow of an arbitrary gas. Various special cases are also discussed.

Liu, Yen↗
NASA NTRS1988

Supercooling effects in faceted eutectic Nb-Si alloys

The effect of melt supercooling on the microstructure of an Nb-58 at. pct Si alloy is investigated experimentally using an electromagnetic levitation apparatus. It is found that, starting with an alloy nominally of eutectic composition, nucleation of Nb5Si3 occurs in the supercooled liquid first. Upon further cooling, the remaining liquid continues to supercool until the second phase, NbSi2 is nucleated, which is commonly accompanied by rapid recalescence. The primary phase exibits a eutectoid-type decomposition. The observations are discussed with reference to the results of quantitative microstructural measurements, compositional and thermal analysis, and preliminary thermodynamic modeling of the phase diagram.

Gokhale, A. B.↗
NASA NTRS1989

Dendrites, viscous fingers, and the theory of pattern formation

Recent developments in the theory of pattern formation in dendritic crystal growth and viscous fingering in fluids are reviewed. Consideration is given to the discovery that weak capillary forces act as singular perturbations which lead to selection mechanisms in dendritic crystal growth and fingering patterns. Other topics include the conventional thermodynamic model of the solidification of a pure substance from its melt, fingering instability, pattern selection, the solvability theory, dendritic growth rates, the bubble effect discovered by Couder et al. (1986), the dynamics of pattern-forming systems, and snowflake formation.

Langer, J. S.↗