Interaction between felsic granitoids and mafic dykes in Bundelkhand Craton: A field,petrographic and crystal size distribution study     

Tanwita Deb  Tapas Bhattacharyya 《Journal of Earth System Science》2018,127(7):102

In Bundelkhand Craton of central India, mafic dykes intruded when granitoids was partly crystallized. Cuspate–lobate boundary along the contact of granitoids and mafic magma indicates magma mingling in outcrop scale while textural evidence of mingling is represented by acicular apatite morphologies, titanite–plagioclase ocelli and ophitic–subophitic texture, mafic clots, resorbed plagioclase, and hornblende–zircon associations. Mingling also caused thermal exchange and fluid activity along the boundary between two coeval magmas. Crystal size distribution analyses for hornblende in the mafic rocks yield concave up curves which is also consistent with interaction of felsic and mafic magmas.  相似文献   

Impact of Kalpana-1 retrieved atmospheric motion vectors on mesoscale model forecast during summer monsoon 2011     

Inderpreet Kaur  Prashant Kumar  S. K. Deb  C. M. Kishtawal  P. K. Pal  Raj Kumar 《Theoretical and Applied Climatology》2015,120(3-4):587-599

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Racing climate change: Collaboration and conflict in California's global climate change policy arena     

Jonathan London  Alex Karner  Julie Sze  Dana Rowan  Gerardo Gambirazzio  Deb Niemeier 《Global Environmental Change》2013,23(4):791-799

Media accounts routinely refer to California's Assembly Bill 32 (AB 32), the Global Warming Solutions Act of 2006, as “landmark” climate change legislation. On its surface, this label is an accurate reflection of the state's forward-thinking stance across many environmental issues including pesticides, toxic substances, solid waste, and air quality. For all its promise, however, AB 32 can also be considered a low point in the landscape of conflict between state environmental regulators and California's environmental justice movement. While the legislation included several provisions to address the procedural and distributive dimensions of environmental justice, the implementation of AB 32 has been marked by heated conflict. The most intense conflicts over AB 32 revolve around the primacy of market mechanisms such as “cap and trade.” This article examines the drivers and the manifestations of these dynamics of collaboration and conflict between environmental justice advocates and state regulators, and pays particular attention to the scalar and racialized quality of the neoliberal discourse. The contentiousness of climate change politics in California offers scholars and practitioners around the world a cautionary tale of how the best intentions for integrating environmental justice principles into climate change policy do not necessarily translate into implementation and how underlying racialized fractures can upend collaboration between state and social movement actors.  相似文献   

Stellar Inversions     

Sarbani Basu 《Astrophysics and Space Science》2003,284(1):153-164

Inversions of oscillation frequencies have proved to be extremelypowerful in studying the structure of the Sun. We examine theconditions under which we can invert oscillation frequenciesof other stars to study their structure. We show that despite thevery limited number of modes that are expected to be observed in otherstars, we can perform inversions that will give localized informationof the stellar core. These results can limit the space of admissiblemodels of a given star.  相似文献   

An exact linearization and decoupling of the integral equations satisfied by time-dependent X- and Y-functions     

S. Karanjai  T. K. Deb 《Astrophysics and Space Science》1993,203(1):135-138

We discuss a simple method of linearization and decoupling of the integral equations satisfied by time-dependentX - andY -functions which play an important rôle in the study of non-stationary radiative transfer problems.  相似文献   

Similarity solutions for propagation of strong plane shock waves in an optically thin atmosphere     

G. Deb Ray  S. N. Banerjee 《Astrophysics and Space Science》1980,68(1):73-86

Similarity solutions, using Planck's diffusion approximation, for propagation of strong plane shock waves in an optically thin grey atmosphere of uniform density are obtained. Solutions for the ratio of specific heats 4/3 and several values of the radiation parameter are compared with those in the absence of any radiation. Excerpts from the results of integrations for different values of the ratio of specific heats are also given in Tables I-III.  相似文献   

Nonplanar ion acoustic solitary waves with superthermal electrons and positrons     

Deb Kumar Ghosh  Prasanta Chatterjee  Biswajit Sahu 《Astrophysics and Space Science》2012,341(2):559-565

The properties of cylindrical and spherical ion acoustic solitary waves (IASWs) are investigated in a three-component unmagnetized, collisionless plasma consisting of warm ion fluid and superthermally distributed electrons and positrons in a nonplanar cylindrical or spherical geometry. Using the reductive perturbation technique, the nonplanar cylindrical and spherical Korteweg-de Vries (KdV) equations are derived. The effects of spectral index of electron and positron, and other plasma parameters are studied. It is found that both negative as well as positive solitary potential structures are formed in nonplanar geometries. The numerical solution shows that amplitude of the soliton is large in spherical geometry in comparison with cylindrical geometry. Numerical results indicate that the amplitude of the soliton is large in spherical geometry in comparison with cylindrical geometry.  相似文献   

Remark on the energy content of a blast wave     

Deb Ray  G. 《Astrophysics and Space Science》1986,127(1):181-183

In this note a comment is made on the total energy content of a blast wave in a stellar model with continuous density distribution. The remark is based on the extensive numerical works carried out by Carruset al. (1951).  相似文献   

Plane relativistic shock waves at the edge of a gas     

G. Deb Ray  Gautam Sanyal 《Astrophysics and Space Science》1981,74(2):453-462

Similarity solutions for propagation of plane relativistic shock waves through a medium of decreasing nucleon density and approaching the edge of the gas as well as for the subsequent motion of the gas after the shock front arrives at the vacuous boundary are studied in this paper. The medium in the pre-disturbed stage is assumed cold and in the disturbed stage its equation of state is taken as that of a photonic gas.  相似文献   

Hindoli Group of Rocks in the Eastern Fringe of the Aravalli-Delhi Orogenic Belt-Archean Secondary Greenstone Belt or Proterozoic Supracrus tals?     

M. Deb  Ralph Thorpe  Dragan Krstic 《Gondwana Research》2002,5(4):879-883

The very low-grade metamorphic sequence of volcano-sedimentary rocks, sandwiched between the platform sediments of the Vindhyan Supergroup to the east and the Banded Gneissic Complex (BGC) to the west, in the eastern fringe of the Aravalli-Delhi orogenic belt, has remained a stratigraphic enigma in the Precambrian geology of Rajasthan. This sequence known earlier as the Gwalior ‘series’ and in contemporary literature as the Hindoli Group, has been considered by several workers as a Proterozoic supracrustal unit and by some others, as an Archean secondary greenstone belt, based purely on geological considerations. U-Pb zircon geochronology was conducted to find an answer to this controversy on samples of felsic volcanics, conformably intercalated with the Hindoli sediments and hence, considered contemporaneous with them. Zircons from a sample of massive rhyodacite gave a concordia age of 1854k7 Ma though zircons from a sample of felsic tuff gave a wide range of ages between 3259-1877 Ma. Careful consideration of the nature of the samples and their constituent zircons suggests that the Hindoli Group rocks represent a low-grade Proterozoic supracrustal cover sequence in the eastern part of the Bhilwara belt, broadly synchronous to the Aravalli-Bhilwara sedimentation around 1.8 Ga.  相似文献