No description available.

Bibliography: leaves 152-156 / ix, 156 leaves : ill ; 31 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, 1986

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. Johannesburg / In this thesis we investigate the evolution of viscous FRW cosmological models for two different constitutive equations for the bulk viscous pressure a, namely (Abbreviation abstract) / Andrew Chakane 2018

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. Johannesburg, / In this thesis we investigate the evolution of viscous FRW cosmological models for two different constitutive equations for the bulk viscous pressure a, namely: The truncated theory,,,,,,,,,,,,,,,, and the full (non-truncated] Israel-Stewart theory ...................We first review the relativistic theory of non-equilibrium thermodynamics developed by Eckart (1940) and the essentially equivalent formulation of the theory given by Landau and Lifshitz (1958). We give a, brief description of the relativistic second-order theories found by Israel and Stewart (1976) and subsequently developed by Pavon, Jou, and co-workers (1982, 1993). All this is done in order to develop the tools for the study of the evolution of FRW cosmological models in the context of causal thermodynamics. We find new exact and perturbative solutions of Einstein's field equations for the truncated Israel-Stewart theory of irreversible thermodynamics. We show that viscous effects speed up the expansion of the universe. We also consider a viscous fluid in the presence of a " non-interacting scalar field and show that inflationary solutions exist. The full theory of bulk viscosity is applied to dissipative FRW spacetimes. New causal viscous inflationary solutions are presented. These solutions extend the results obtained by Maartens (1995a) to cases where the coefficient of bulk viscosity e and the relaxation time r are independent. Power-law solutions for the scale factor are shown to exist. / Andrew Chakane 2018

xii, 218 leaves / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.1978) from the Dept. of Mathematical Physics, University of Adelaide

Bibliography: leaves 100-106. Studies different models of "quintessence", in particular, a quintessence arising from an ultra-light pseudo Nambu-Goldstone boson. Overviews dynamical properties for these models using phase-space analyses to study attractor and tracker solutions. Studies high-redshift type Ia supernovae constraints on these models. Studies the impact of a simple phenomenological model for supernovae luminosity evolution on the PNGB models and the potentials of a future supernovae data set to discriminate the PNGB models over the other quintessence models. Studies gravitational lensing statistics of high luminosity quasars upon the quintessence models.

Bibliography: leaves 100-106. / v, 107 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Studies different models of "quintessence", in particular, a quintessence arising from an ultra-light pseudo Nambu-Goldstone boson. Overviews dynamical properties for these models using phase-space analyses to study attractor and tracker solutions. Studies high-redshift type Ia supernovae constraints on these models. Studies the impact of a simple phenomenological model for supernovae luminosity evolution on the PNGB models and the potentials of a future supernovae data set to discriminate the PNGB models over the other quintessence models. Studies gravitational lensing statistics of high luminosity quasars upon the quintessence models. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physics and Mathematical Physics, 2001

Includes bibliographical references (leaves 168-179). / xiii, 179 leaves ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Finds that the post-Newtonian approximation seems to be a better approximation of the general relativistic theory than the standard Newtonian theory. / Thesis (Ph.D.)--Adelaide University, Dept. of Physics and Mathematical Physics, 2001

The influence of matter described by the Vlasov equation, on the evolution of anisotropy in the spatially-homogeneous universes, called the Bianchi cosmologies, is studied. Due to the spatial-homogeneity, the Einstein equations for each Bianchi Type are reduced to a set of coupled ordinary differential equations, which has Hamiltonian form with the metric components being the canonical coordinates. In the vacuum Bianchi cosmologies, it is known that a curvature potential, which comes from the symmetries of the three-dimensional Lie groups, determines the basic properties of the evolution of anisotropy. In this work, matter potentials are constructed for Vlasov matter. They are obtained by first introducing a new matter action principle for the Vlasov equation, in terms of a conjugate pair of functions, and then enforcing the symmetry to obtain a reduction. This yields an expression for the matter potential in terms of the phase space density, which is further reduced by assuming cold streaming matter. Some vacuum Bianchi cosmologies and Type I with Vlasov matter are compared. It is shown that the Vlasov-matter potential for cold streaming matter results in qualitatively distinct dynamics from the well-known vacuum Bianchi cosmologies. / text

Errata inserted opposite p.177. / Bibliography: p. 173-177. / x, 177 p. : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The classical dynamical structure of cosomological models in which the matter content of the universe consists of a scalar field with arbitrary non-negative potential is analyzed in full. (abstract) / Thesis (Ph.D.)--University of Adelaide, Dept. of Physics and Mathematical Physics, 1996?