6 citations · 29 across the 11 of their papers we have counts for
11 papers
Thermodynamic Interpretation of the Kompanneets-Chernov-Kantowski-Sachs Solutions
Salvador Mengual, Joan Josep Ferrando
The spatially homogeneous perfect fluid solutions by Kompanneets-Chernov-Kantowski-Sachs are interpreted as a thermodynamic perfect fluid in isentropic evolution, namely, the isent…
Dimension of the isometry group in type N vacuum solutions: an IDEAL approach
Juan Antonio Sáez, Salvador Mengual, Joan Josep Ferrando
The necessary and sufficient conditions for a type N vacuum solution (with cosmological constant) to admit a group of isometries of dimension are given in terms of the invarian…
Spatially-Homogeneous Cosmologies
Juan Antonio Sáez, Salvador Mengual, Joan Josep Ferrando
The necessary and sufficient conditions for a perfect fluid solution to define a spatially-homogeneous cosmology are achieved. These conditions are Intrinsic, Deductive, Explicit a…
Thermodynamics of the universes admitting isotropic radiation
Salvador Mengual, Joan Josep Ferrando, Juan Antonio Sáez
The thermodynamic interpretation of the Stephani Universes is studied in detail. The general expression of the speed of sound and of the thermodynamic schemes associated with a the…
Dimension of the isometry group in spacetimes with an invariant frame
Juan Antonio Sáez, Salvador Mengual, Joan Josep Ferrando
The necessary and sufficient conditions for a spacetime with an invariant frame to admit a group of isometries of dimension are given in terms of the connection tensor asso…
On the flow of perfect energy tensors
Juan Antonio Sáez, Salvador Mengual, Joan Josep Ferrando
The necessary and sufficient conditions are obtained for a unit time-like vector field to be the unit velocity of a divergence-free perfect fluid energy tensor. This plainly ki…
Hydrodynamic approach to the Synge gas
Salvador Mengual, Joan Josep Ferrando, Juan Antonio Sáez
The necessary and sufficient conditions for a perfect energy tensor to describe the energy evolutions of a monoatomic relativistic Synge gas are obtained. Then, a Rainich-like theo…
Thermodynamic perfect fluid spheres admitting an orthogonal flat synchronization
Salvador Mengual, Joan Josep Ferrando
We analyze the interpretation of the spherically symmetric perfect fluid solutions that admit a flat synchronization orthogonal to the fluid flow as a thermodynamic perfect fluid i…
T-model field equations: the general solution
Joan Josep Ferrando, Salvador Mengual
We analyze the field equations for the perfect fluid solutions admitting a group G of isometries acting on orbits S whose curvature has a gradient that is tangent to the fl…
A thermodynamic approach to the T-models
Joan Josep Ferrando, Salvador Mengual
The perfect fluid solutions admitting a group G of isometries acting on orbits S whose curvature has a gradient which is tangent to the fluid flow (T-models) are studied fr…
Obtaining the multiple Debever null directions
Juan Antonio Sáez, Salvador Mengual, Joan Josep Ferrando
The explicit expression of the multiple Debever null directions of an algebraically special spacetime are obtained in terms of the electric and magnetic parts of the Weyl tensor. A…