8,456 research outputs found
Cosmic Evolution in Generalised Brans-Dicke Theory
We have studied the Generalised Brans-Dicke theory and obtained exact
solutions of a(t),phi(t),and omega(t) for different epochs of the cosmic
evolution .We discuss how inflation,decceleration,cosmic acceleration can
result from this solution.The time variation of G(t) is also examined.Comment: 12 pages, no figure
Application of Relativistic Coupled-cluster Theory to Electron Impact Excitations of Mg in the Plasma Environment
A relativistic coupled-cluster (RCC) theory is implemented to study electron
impact excitations of atomic species. As a test case, the electron impact
excitations of the resonance transitions
are investigated in the singly charged magnesium (Mg) ion using this
theory. Accuracies of wave functions of Mg are justified by evaluating its
attachment energies of the relevant states and compared with the experimental
values. The continuum wave function of the projectile electron are obtained by
solving Dirac equations assuming distortion potential as static potential of
the ground state of Mg. Comparison of the calculated electron impact
excitation differential and total cross-sections with the available
measurements are found to be in very good agreements at various incident
electron energies. Further, calculations are carried out in the plasma
environment in the Debye H\"uckel model framework, which could be useful in the
astrophysics. Influence of plasma strength on the cross-sections as well as
linear polarization of the photon emission in the transition is investigated for different incident electron energies.Comment: 9 pages, 1 table and 3 figure
Gravitational Waves in Generalised Brans-Dicke Theory
We have solved cosmological gravitational Wave(GW)equation in the frame work
of Generalised Brans-Dicke(GBD) theory for all epochs of the Universe.The
solutions are expressed in terms of the present value of the Brans-Dicke
coupling parameter .It is seen that the solutions represent
travelling growing modes for negative values of for all epochs of
the Universe.Comment: 7Pages,no figure
Effect of both Z and Z'-mediated flavor-changing neutral currents on the baryonic rare decay decays into
We study the effect of both Z and Z'-mediated flavor-changing neutral
currents (FCNCs) on the rare
decay. We find the branching ratio is reasonably enhanced from its standard
model value due to the effect of both Z and Z'-mediated FCNCs, and gives the
possibility of new physics beyond the standard model. The contribution of
Z'-boson depends upon the precise value of the mass of Z' boson.Comment: 14 page
Melting and Casting of Non-ferrous Metals and Alloys
In general sense, a casting is produced when molten metal is poured into a mould and left to cool and solidify. The other name given to a casting is 'Founding'. In casting process, metal/ alloy component parts of desired shapes are produced by pouring the molten metal/alloy into a prepared mould (of that shape) and then allowing the molten metal/alloy to cool and solidify. This solidified piece of metal/alloy is known as a casting
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