Propagation of axi-symmetric relativistic shock waves     

G. Deb Ray  T. K. Chakraborty  S. N. Banerjee 《Astrophysics and Space Science》1980,72(2):323-345

Solutions in series for the propagation of relativistic shock waves with axial symmetry are obtained in this paper. We assume that the gaseous elements move almost radially and that the disturbance moves through a cold gas at rest wherein the nucleon number density and the energy density obey an exponential law of distance from a given plane. The motion is sustained by continuous explosions in the central region liberating energy varying as the cube of time. Also, we assume the equation of state of the moving elements as that of photonic gas.  相似文献   

Propagation of cylindrical relativistic shock waves in the presence of a magnetic field     

G. Deb Ray  T. K. Chakraborty 《Astrophysics and Space Science》1979,61(1):101-110

In this paper we obtain similarity solutions for the propagation of cylindrical relativistic shock waves in the presence of a constant azimuthal magnetic field or in its absence for the medium, where the nucleon number density is uniform. The shock surface moves with constant velocity and the total energy of the disturbance is dependent on time. The solutions are applicable only to an isothermal medium or a cold gas.  相似文献   

Comets: Edited by Laurel L. Wilkening. Assisted by Mildred Shapley Matthews. Univ. of Arizona Press,Tucson, 1982. 770 pp., Cloth, $29.95     

Ray L. Newburn 《Icarus》1982,52(3):585-586

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The enigma of the Uranian satellites' orbital eccentricities     

Steven W. Squyres  Ray T. Reynolds  Jack J. Lissauer 《Icarus》1985,61(2):218-223

Using recently published determinations of the diameters and orbital elements of the uranian satellites and assuming reasonable dissipation functions and rigidities for icy satellites, the eccentricity decay times for the satellites were calculated. For the inner three, decay times are on the order of 10⁷–10⁸ years, making it difficult to understand why these satellites still have their observed eccentricities. The three inner satellites have a near-commensurability in their mean motions that may be able to force their eccentricities at some time in the future, but cannot force them now. Several possible explanations exist: (1) The reported eccentricities are incorrect, and are in fact near-zero. (2) The reported mean motions are incorrect, and an exact commensurability exists. (3) The physical properties that we have assumed for the satellites are grossly in error (e.g., dissipation function Q is in reality very large). (4) The system is evolving very rapidly, perhaps from a previous state of higher eccentricity. Cases 1 and 2 are unlikely when one considers the quality of existing data. Case 3 would be more consistent with non-icy compositions. Cases 2 and 4 would imply some tidal heating of the satellites, particularly Ariel. A new lower bound of ～ 1.7 × 10⁴ on the Q of Uranus is calculated from the mass of Ariel and its proximity to Uranus.  相似文献   

Remote sensing of lunar pyroclastic mantling deposits     

Lisa R. Gaddis  Carle M. Pieters  B. Ray Hawke 《Icarus》1985,61(3):461-489

Mantling deposits on the Moon are considered to be pyroclastic units emplaced on the lunar surface as a result of explosive fire fountaining. These pyroclastic units are characterized as having low albedos, having smooth fine-textured surfaces, and consisting in part of homogeneous, Febearing volcanic glass and partially crystallized spheres. Mantling units exhibit low returns on depolarized 3.8-cm radar maps, indicating an absence of surface scatterers in the 1- to 50-cm-size range. A number of reflectance spectra from several regional pyroclastic deposits are presented for the first time; these data support a previous interpretation that mantling units have a unique spectral signature which is indicative of the presence of a significant Fe-bearing volcanic glass component. The Rima Bode region is discussed as an example of an area in which several types of remote sensing data (including 3.8-cm radar, spectral reflectance, and multispectral vidicon data) were used to reconstruct the geologic events surrounding the emplacement of a regional pyroclastic mantling deposit. The recognition of numerous varieties of volcanic glass samples, especially relatively high-albedo (e.g., green, yellow) glasses, suggests the existence of additional, unrecognized mantling deposits with albedos higher than those studied to date. On the basis of the remote sensing data summarized and presented, five new areas have been identified which may represent higher-albedo regional pyroclastic deposits.  相似文献   

ELECTROLYTIC CORROSION OF IRON METEORITES     

Stanford L. Tackett  Ray A. Tucker  Floyd R. Duncan 《Meteoritics & planetary science》1970,5(1):43-55

Six iron meteorites were electrolyzed and the resulting corrosion was studied by a potentiostatic technique. It was found that both iron and nickel in the kamacite phase dissolve, and that neither iron nor nickel dissolve from taenite. The rate of corrosion was shown to be inversely proportional to the nickel content. However, structure, as well as nickel content, plays an important part in the electrolytic process. The Coya Norte, Chile meteorite dissolved more rapidly and more easily (at a lower potential) than did pure iron even though the Coya Norte meteorite contains 5.5% nickel.  相似文献   

The structural and geochemical evolution of the Singhbhum granite batholithic complex, India     

A.K. Saha  S.L. Ray 《Tectonophysics》1984,105(1-4)

The Singhbhum granite batholithic complex of eastern India is composed mainly of (a) the Older Metamorphic Group, tonalite (-trondhjemite) gneiss (OMTG, 3800 Ma old), whch intruded synkinematically into the enveloping Older Metamorphic Group (OMG, > 3800 Ma old) and (b) the Singhbhum granite (SBG) consisting of three distinct but closely related phases of at least twelve separate magmatic units of granodiorite-granite (2950 Ma old), and a number of patches of granitised OMG orthoamphibolites. Geochemical studies including REE and LIL elements suggest that (a) the OMG orthoamphibolites were derived either by re-melting of a K-poor basalt (LKT) or of mantle peridotite with high concentration of LIL elements, (b) the OMG tonalite was derived by partial melting of amphibolite and (c) the Singhbhum granite magmas appear to have formed in two distinct modes: (i) partial melting of amphibolite for the magmas of phases I and II and (ii) partial melting of a siliceous, garnet-bearing granulite for magmas of the phase III units.  相似文献   

An ion microprobe study of the partitioning of trace elements between clinopyroxene and liquid in the system diopside-albite-anorthite     

G.L. Ray  N. Shimizu  S.R. Hart 《Geochimica et cosmochimica acta》1983,47(12):2131-2140

The partitioning of trace elements (Sc, Ti, Sr and Sm) between diopsidic clinopyroxene and liquid was studied experimentally in the system diopside-albite-anorthite at 1250°C, 1300°C and 1345°C at 1 atm. Twelve different bulk compositions were selected to study the effects of temperature and chemical composition. A Cameca ion microprobe was used to determine trace element concentrations in both clinopyroxene and liquid. Experiments of different run duration $\text{1}\text{4}\text{8}\text{?}$ days) showed that equilibrium was approached in less than 4 days at 1275°C. Equilibrium was also evaluated by a reversal run. A series of runs of constant bulk composition but with variable trace element contents showed that Henry's Law was obeyed over concentration ranges of the trace elements similar to those encountered in natural systems. The partition coefficients show significant ranges: Sc, 0.345~2.61; Ti, 0.084~0.214; Sr, 0.075~0.136; Sm, 0.054~0.328; the values are comparable with those obtained experimentally by other investigators. The partition coefficients vary as a function of both temperature and chemical composition. The experimental results are discussed in terms of exchange equilibria using the Bottinga-Weill silicate melt model. It is demonstrated that analytical uncertainties of both major and trace elements play an important role in understanding trace element exchange equilibria; propagation of analytical errors in the thermodynamic treatment is equally important.  相似文献   

SH waves in an inhomogeneous complete or incomplete wedges,I     

S. Ray 《Pure and Applied Geophysics》1971,85(1):161-181

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Cadmium in tissues of lobsters captured near a lead smelter     

S. Ray  D.W. McLeese  L.E. Burridge 《Marine pollution bulletin》1981,12(11):383-386

Cadmium distribution among tissues of lobsters (Homarus americanus) from Belledune Harbour near a lead smelter was determined and compared with that of lobsters from uncontaminated areas of Stonehaven, N.B., Canada and from Maine, USA. The hepatopancreas contained more than 90% of the body burden of cadmium. High concentrations of cadmium were also present in green glands and gills. Cadmium concentrations in the hepatopancreas, gills, and green glands were correlated with the concentrations in most of the other tissues.  相似文献