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1.
In the presence of perfect fluid with bulk viscosity homogeneous isotropic Friedmann Cosmologies are studied in the scale covariant theory of gravitation. Using special law of variation for Hubble’s parameter, a class of solutions is found. The physical properties of the model are also investigated. 相似文献
2.
N. Ibotombi Singh S. Surendra Singh S. Romaleima Devi A. Sumati Devi 《Astrophysics and Space Science》2009,324(1):67-70
We consider cosmology with the gravitational and cosmological constants generalized as coupling scalars in Einstein’s theory.
A general method of solving the field equations is given. We study here the exact solutions for negative pressure models satisfying
G=G
0(R/R
0)
n
. 相似文献
3.
Cosmology with the gravitational and cosmological constants generalized as coupling scalars in Einsteins theory is considered.
A general method of solving the field equations is given. Exact solution for Zeldovich fluid satisfying G=G
0(R/R
0)
n
is given. 相似文献
4.
Relativistic cosmological field equations are obtained for a Robertson-Walker space time interacting with viscous fluid and
massive scalar field. The cosmological solutions to the field equations are obtained and the nature of the scalar field as
well as the viscous fluid are studied. It is found that the solutions obtained are realistic only for a closed Universe.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
The study of Einstein field equations describing the Robertson-Walker universe with the Brans-Dicke field and perfect fluid
has been made. It is found that the exact solutions to the B-D field interacting with perfect fluid reduce to a false vaccum
with cosmological constant and without cosmological constant the solution reduce to the exact solution of the matter dust
distribution in the Brans-Dicke cosmology.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
6.
A study of the slowly rotating cosmological universe filled with viscous fluid has been made by assuming the matter angular
velocity Ω is proportional to the metric angular velocity Ω and the Universe is expanding under the Hubble's law. The physical
properties of the solutions obtained are also discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
7.
8.
Friedmann Robertson Walker cosmological models with bulk viscosity are constructed in the scale covariant theory of gravitation.
A new class of solutions for the field equations of the model is found by applying variable deceleration parameter. Some physical
models of these solutions are briefly discussed in this paper. 相似文献
9.
The peridotites of the Manipur Ophiolite Complex (MOC) have been examined based on mineral chemistry, major elements and PGE
contents. They represent high-magnesian cumulates with Mg# > 0.90 (Mg/Mg+Fe) in olivine and Cr# > 0.12 (Cr/Cr+Al) in spinel.
High Mg* contents of the olivine show that these rocks are most likely derived from partial melting of the residual upper
mantle. The peridotites contain higher concentration of Palladium Group PGE (PPGE) (Rh=4.4−6.6ppb; Pd=336−458ppb and Pt=14.6−36.4ppb)
than the Iridium Group PGE (IPGE) (Os=2.4−5.8ppb; Ir=3.2−4.16ppb and Ru=5.2−7ppb). These are characterized by overall enrichment
of PGE concentration (σPGE=365.8 − 516.6 ppb) and high ratio of (Pt+Pd)/(Os+Ir+Ru). This suggests that the rocks are formed
by partial melting and crystal fractionation of olivine-rich (picritic) magma. 相似文献
10.
The perturbation by a spherical rotating shell is investigated in a homogeneous and isotropic cosmological model of viscous fluid distribution to first order in angular velocity (r, t) of matter and the metric rotation function (r, t) which is uniform and non-uniform the exact solutions for (r, t) are obtained for all cosmological models. The physical properties of these solutions are discussed. 相似文献