Rajagopalan Nair K - Academia.edu (original) (raw)
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Books by Rajagopalan Nair K
In this paper we consider a flat FLRW universe with bulk viscous Zel'dovich fluid as the cosmic c... more In this paper we consider a flat FLRW universe with bulk viscous Zel'dovich fluid as the cosmic component. Considering the bulk viscosity as characterized by a constant bulk viscous coefficient, we analyze the evolution of the Hubble parameter. Type Ia Supernovae data is used for constraining the model and for extracting the constant bulk viscous parameter and present the Hubble parameter. We also present the analysis of the scale factor, equation of state, and deceleration parameter. The model predicts the later time acceleration and is also compatible with the age of the universe as given by the oldest globular clusters. Study of the phase-space behavior of the model shows that a universe dominated by bulk viscous Zel'dovich fluid is stable. But the inclusion of a radiation component in addition to the Zel'dovich fluid makes the model unstable. Hence, even though the bulk viscous Zel'dovich fluid dominated universe is a feasible one, the model as such fails to predict a prior radiation dominated phase.
Papers by Rajagopalan Nair K
Physica C-superconductivity and Its Applications - PHYSICA C, 1992
The systematics of the superconducting transition temperatures of A3C60 compounds are discussed i... more The systematics of the superconducting transition temperatures of A3C60 compounds are discussed in terms of possible localisation effects that could arise from a size mismatch of the A ions in tetrahedral and octahedral sites of the close-packed C60 lattice. This is based on a comparison of the resistivity data in various superconductors including high-temperature superconductors and conventional superconductors.
In this paper we consider a flat FLRW universe with bulk viscous Zel'dovich fluid as the cosmic c... more In this paper we consider a flat FLRW universe with bulk viscous Zel'dovich fluid as the cosmic component. Considering the bulk viscosity as characterized by a constant bulk viscous coefficient, we analyze the evolution of the Hubble parameter. Type Ia Supernovae data is used for constraining the model and for extracting the constant bulk viscous parameter and present the Hubble parameter. We also present the analysis of the scale factor, equation of state, and deceleration parameter. The model predicts the later time acceleration and is also compatible with the age of the universe as given by the oldest globular clusters. Study of the phase-space behavior of the model shows that a universe dominated by bulk viscous Zel'dovich fluid is stable. But the inclusion of a radiation component in addition to the Zel'dovich fluid makes the model unstable. Hence, even though the bulk viscous Zel'dovich fluid dominated universe is a feasible one, the model as such fails to predict a prior radiation dominated phase.
Physica C-superconductivity and Its Applications - PHYSICA C, 1992
The systematics of the superconducting transition temperatures of A3C60 compounds are discussed i... more The systematics of the superconducting transition temperatures of A3C60 compounds are discussed in terms of possible localisation effects that could arise from a size mismatch of the A ions in tetrahedral and octahedral sites of the close-packed C60 lattice. This is based on a comparison of the resistivity data in various superconductors including high-temperature superconductors and conventional superconductors.