Torsion and shear effect on a Big Rip model in a gravitational field

Abstract

In this paper, we investigate the effects of torsion and shears within the framework of the gravitational field with torsion in early and late cosmology. General relativity and torsion field equations are constructed using absolute parallel geometry. The Big Rip model of the Universe has been presented using a special class of Riemann-Cartan geometry and the law of variation of Hubble's parameter. The model does not depend on the curvature constant. The positive condition of the energy density of the matter is satisfied in this model. This cosmological model shows that the torsion and shear effect is strong at the beginning of the Big Bang and at the end of the universe. Through the examination of precise cases of the parameters and initial conditions, we can show that for suitable ranges of the parameters, the dynamic torsion scalar model can exhibit features similar to those of the currently observed accelerating universe. The relationship between the torsion and shear scalars is investigated, and their impact on the accelerating universe is addressed apart from the idea of dark energy.

Mathematical modeling and simulation of porosity on thermomechanical properties of UHTCs under hypersonic conditions

“…The consideration of gravitational force 20 means that we are assuming the sample that operates at hypersonic speed in the lower earth atmosphere. Hence, the attractive mass considered will be the one of the Earth (5.9722 · 10 24 kg), whereas the distance will be assumed to be the maximum height for lower earth atmosphere (80 km) plus the earth radius (6371 km).…”