STANDARD COSMOLOGY: CAUSAL HOMOGENIZATION CONDITION AND ENERGY DISSIPATION

1995 ◽  
Vol 04 (04) ◽  
pp. 549-555 ◽  
Author(s):  
SOFIANE CHALLANE-TLEMSANI ◽  
GÉRARD LE DENMAT
Keyword(s):  
Energy Dissipation ◽  
Bulk Viscosity ◽  
Irreversible Thermodynamics ◽  
Early Evolution ◽  
Extended Irreversible Thermodynamics ◽  
Standard Cosmology ◽  
Friedmann Robertson Walker ◽  
Homogenization Condition

The effect of a transient dissipative phase, during the early evolution of the cosmic fluid, is investigated in the framework of the Extended Irreversible Thermodynamics. The role played by the bulk viscosity is considered in the case of a spatially flat Friedmann-Robertson-Walker model, and we discuss a solution which allows the condition of causal homogenization of a hypersurface t=constant to be satisfied.

RADIATING COLLAPSE WITH VANISHING WEYL STRESSES

2005 ◽  
Vol 14 (03n04) ◽  
pp. 667-676 ◽  
Author(s):  
S. D. MAHARAJ ◽  
M. GOVENDER
Keyword(s):  
Irreversible Thermodynamics ◽  
Temperature Profiles ◽  
Junction Conditions ◽  
Einstein Field Equations ◽  
Field Equations ◽  
Extended Irreversible Thermodynamics ◽  
Recent Approach ◽  
Dust Solution ◽  
Limiting Case

In a recent approach in modeling a radiating relativistic star undergoing gravitational collapse the role of the Weyl stresses was emphasized. It is possible to generate a model which is physically reasonable by approximately solving the junction conditions at the boundary of the star. In this paper we demonstrate that it is possible to solve the Einstein field equations and the junction conditions exactly. This exact solution contains the Friedmann dust solution as a limiting case. We briefly consider the radiative transfer within the framework of extended irreversible thermodynamics and show that relaxational effects significantly alter the temperature profiles.

Multi-component Diffusion in the Extended Irreversible Thermodynamics Framework

2009 ◽  
Author(s):  
George D. Verros ◽  
Fotios Giovannopoulos ◽  
George Maroulis ◽  
Theodore E. Simos
Keyword(s):  
Irreversible Thermodynamics ◽  
Extended Irreversible Thermodynamics
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