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A spatially homogeneous and isotropic Robertson-Walker model with zero-curvature of the universe is studied in Saez-Ballester
scalar-tensor theory. Exact solutions of the field equations are obtained for two different early phases of the universe viz.
the inflationary and the radiation-dominated phases by using gamma-law equation of state p=(γ-1)ρ in the presence of perfect fluid. The γ-index describing the material content varies continuously with cosmic time
so that in the course of its evolution, the universe goes through a transition from an inflationary phase to a radiation-dominated
phase. The coupling parameterω is allowed to depend on the cosmic time. The nature of scalar field and other physical significance
have also been discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Shriram Srinivasan Jeffrey Hyman Satish Karra Daniel O’Malley Hari Viswanathan Gowri Srinivasan 《Computational Geosciences》2018,22(6):1515-1526
We propose a multi-fidelity system reduction technique that uses weighted graphs paired with three-dimensional discrete fracture network (DFN) modelling for efficient simulation of subsurface flow and transport in fractured media. DFN models are used to simulate flow and transport in subsurface fractured rock with low-permeability. One method to alleviate the heavy computational overhead associated with these simulations is to reduce the size of the DFN using a graph representation of it to identify the primary flow sub-network and only simulate flow and transport thereon. The first of these methods used unweighted graphs constructed solely on DFN topology and could be used for accurate predictions of first-passage times. However, these techniques perform poorly when predicting later stages of the mass breakthrough. We utilize a weighted-graph representation of the DFN where edge weights are based on hydrological parameters in the DFN that allows us to exploit the kinematic quantities derivable a posteriori from the flow solution obtained on the graph representation of the DFN to perform system reduction and predict the later stages of the breakthrough curve with high fidelity. We also propose and demonstrate the use of an adaptive pruning algorithm with error control that produces a pruned DFN sub-network whose predicted mass breakthrough agrees with the original DFN within a user-specified tolerance. The method allows for the level of accuracy to be a user-controlled parameter. 相似文献
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The assessment of potential land use in the proposed irrigation command using Remote Sensing and GIS
Suresh Kumar Shriram B Dhaimodkar L M Pande 《Journal of the Indian Society of Remote Sensing》2002,30(3):157-166
Standard false colour composites (Std. FCC) on 1:50,000 scale was visually interpreted in conjunction with soil survey to prepare physiographic-soil map. Thirteen mapping units were delineated indicating soil association at family-level. Soil and land resource was evaluated for their land capability and irrigation suitability for its sustained use under irrigation. Land capability and land irrigability maps were generated as attribute map. These maps were integrated to suggest potential land use map. Current land use/land cover map prepared by visual analysis was spatially analysed in relation to potential land use to study potential changes in land use / land cover using GIS. The study reveals that 14.66% area has no limitation and can be brought to intensive agriculture by double cropping. 相似文献
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Suresh Kumar Shriram B Dhaimodkar L M Pande 《Journal of the Indian Society of Remote Sensing》2005,33(2):239-244
Short Note
Application of remote sensing and GIS in watershed characterization and management 相似文献
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