Yazar "Khadekar, G. S." seçeneğine göre listele

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    Domain wall with strange quark matter in kaluza-klein type cosmological model
    (Springer/Plenum Publishers, 2009) Khadekar, G. S.; Wanjari, Rupali; Özel, Cenap
    In this study we have analyzed the Kaluza-Klein type Robertson Walker (RW) cosmological model by considering variable cosmological constant term Lambda of the form: Lambda similar to (R) over dot(2)/R(2), Lambda similar to (sic)/R and Lambda similar to rho in the presence of strange quark matter with domain wall. The various physical aspects of the model are also discussed.
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    Early universe with variable cosmological constants in higher dimensional space time
    (Springer/Plenum Publishers, 2008) Khadekar, G. S.; Kondawar, Gopal L.; Özel, Cenap
    The field equations with variable cosmological and gravitational constants are consider in the presence of perfect fluid for Kaluza-Klein type cosmological model. The exact solutions of the field equations are obtained by using the gamma law equation of state p = (gamma - 1)rho in which the parameter gamma depends on scale factor R. The functional form of gamma(R) is used to analyze a wide range of cosmological solution at early universe for two phases in cosmic history: inflationary phase and radiation dominated phase. The corresponding physical interpretation of cosmological solution are also discussed in the framework of higher dimensional space time.
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    Early viscous universe with variable cosmological and gravitational constants in higher dimensional space time
    (Springer Science+Business Media, LLC, part of Springer Nature, 2008) Khadekar, G. S.; Kondawar, Gopal L.; Kamdi, Vaishali; Özel, Cenap
    In this paper we present a number of classes of solutions of the Einstein's field equations with variable G, Lambda and bulk viscosity for a Kaluza-Klein type of cosmological model. The solutions are obtained by using gamma-law equation of state p = (gamma - 1)rho, where adiabatic parameter gamma-varies continuously as the universe expand. A unified description of the early evolution of the universe is discussed with number of possible assumption on the bulk viscous term and gravitational constant in which an inflationary phase followed by radiation-dominated phase. We also investigate the cosmological model with constant and time dependent bulk viscosity along with constant and time dependent gravitational constant. In all cases, the cosmological constant Lambda found to be positive and decreasing function of time which supports the results obtained from recent supernovae Ia observations. The important physical behaviour of the early cosmological model has also been discussed in the frame work of higher dimensional space-time.
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    Higher dimensional lambda-CDM üniverse: A phenomenological approach with many possibilities
    (Springer/Plenum Publishers, 2009) Khadekar, G. S.; Kamdi, Vaishali; Özel, Cenap
    In this paper we investigate the Lambda-CDM universe by selecting the specific time dependent form of Lambda, viz. (Lambda) over dot proportional to H(3), in the context of 5- dimensional space time. Time-dependent form of equation of state parameter w is derived along with a possible signature flip of deceleration parameter q. It is also observed that a present age of the Universe, calculated for some specific values of parameter agrees very well with the observational data.
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    Higher dimensional unified description of early universe with variable G and Lambda
    (Springer/Plenum Publishers, 2008) Khadekar, G. S.; Sarada, B.; Özel, Cenap
    A homogeneous and isotropic Friedmann-Robertson-Walker (FRW) model with varying gravitational and cosmological constant is studied in the context of higher dimensional space time. Exact solution of the field equations are obtained by using the "gamma law" equation of state p=(gamma-1)rho, where gamma is adiabatic parameter varies continuously as the universe expands. The functional form gamma which is assumed to be the function of scale factor R as proposed by Carvalho (1996) is used to analyse the behavior of scale factor R, cosmological constant Lambda and the gravitational constant G for two different phases: inflation and radiation. The various physical aspects of the early cosmological models has also been discussed in the framework of higher dimensional space time.
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    Higher dimensional unified description of early universe with variable gravitational and cosmological constants
    (Springer/Plenum Publishers, 2008) Khadekar, G. S.; Kondawar, Gopal L.; Kamdi, Vaishali; Özel, Cenap
    In this paper we consider the five dimensional cosmological model with variable gravitational and cosmological constants in the presence of perfect fluid in Kaluza-Klein theory of gravitation. The exact solutions of the field equations are obtained by using the gamma law equation of state p=(gamma-1)rho in which the parameter gamma depends on scale factor R. A unified description of early universe is presented with the assumption Lambda = beta H(2) supercript stop in which inflationary phase is followed by radiation dominated phase. The various physical aspects of the cosmological models are also discussed in the framework of higher dimensional space time.