scholarly journals Physical Quantities of Reissner-Nordström Spacetime with Arbitrary Function and Regularized Procedure

2013 ◽  
Vol 2013 ◽  
pp. 1-13
Author(s):  
Gamal G. L. Nashed
Keyword(s):  
Total Energy ◽  
Arbitrary Function ◽  
Continuation Method ◽  
Teleparallel Gravity ◽  
Spherically Symmetric ◽  
Time Coordinate ◽  
First Law Of Thermodynamics ◽  
Relevant Result ◽  
Physical Quantities ◽  
Gauge Connection

We use the covariant teleparallel approach to compute the total energy ofa spherically symmetric frame with an arbitrary function, that is,ℑ(r). We show how the total energy is always effected by the inertia. When use is made of the pure gauge connection, teleparallel gravity always yields the physically relevant result. We also calculate the total conserved charge and show how inertia spoils the physics in the time coordinate direction. Therefore, a regularized expression is employed to get a plausible value of energy. Finally, we use the Euclidean continuation method, in the context of TEGR, to calculate the energy, Hawking temperature, entropy, and first law of thermodynamics.

scholarly journals Janis–Newman–Winicour and Wyman Solutions are the Same

1997 ◽  
Vol 12 (27) ◽  
pp. 4831-4835 ◽  
Author(s):  
K. S. Virbhadra
Keyword(s):  
Exact Solution ◽  
Scalar Field ◽  
Total Energy ◽  
Space Time ◽  
Massless Scalar ◽  
Spherically Symmetric ◽  
Scalar Equations

We show that the well-known most general static and spherically symmetric exact solution to the Einstein-massless scalar equations given by Wyman is the same as one found by Janis, Newman and Winicour several years ago. We obtain the energy associated with this space–time and find that the total energy for the case of the purely scalar field is zero.

scholarly journals Total Energy of Charged Black Holes in Einstein-Maxwell-Dilaton-Axion Theory

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Murat Korunur ◽  
Irfan Açıkgöz
Keyword(s):  
Black Holes ◽  
Total Energy ◽  
Energy Content ◽  
Teleparallel Gravity ◽  
The Other ◽  
Energy Distributions ◽  
Asymptotically Flat ◽  
Charged Black Holes ◽  
Momentum Complex ◽  
Limiting Case

We focus on the energy content (including matter and fields) of the Møller energy-momentum complex in the framework of Einstein-Maxwell-Dilaton-Axion (EMDA) theory using teleparallel gravity. We perform the required calculations for some specific charged black hole models, and we find that total energy distributions associated with asymptotically flat black holes are proportional to the gravitational mass. On the other hand, we see that the energy of the asymptotically nonflat black holes diverge in a limiting case.

scholarly journals Accelerating Universe with Viscous Cosmic String in Quadratic Form of Teleparallel Gravity

2019 ◽  
Vol 11 (3) ◽  
pp. 249-262
Author(s):  
S. R. Bhoyar ◽  
V. R. Chirde ◽  
S. H. Shekh
Keyword(s):  
Cosmic String ◽  
Teleparallel Gravity ◽  
Negative Slope ◽  
Accelerating Universe ◽  
Field Equations ◽  
Physical Behavior ◽  
Torsion Scalar ◽  
Bulk Viscous ◽  
The Universe ◽  
Physical Quantities

In this paper, we have investigated Kantowaski-Sachs cosmological model with bulk viscous and cosmic string in the framework of Teleparallel Gravity so called f(T) gravity, where T denotes the torsion scalar. The behavior of accelerating universe is discussed towards the particular choice of f(T) = Α(T) + β(T)m. The exact solutions of the field equations are obtained by applying variable deceleration parameter which is linear in time with a negative slope. The physical behavior of these models has been discussed using some physical quantities. Also, the function of the torsion scalar for the universe is evaluated.

scholarly journals Characterization of Air-Based Photovoltaic Thermal Panels with Bifacial Solar Cells

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
P. Ooshaksaraei ◽  
K. Sopian ◽  
R. Zulkifli ◽  
Saleem H. Zaidi
Keyword(s):  
Power Generation ◽  
Total Energy ◽  
Electrical Power ◽  
Exergy Efficiency ◽  
Solar Panels ◽  
First Law Of Thermodynamics ◽  
Laws Of Thermodynamics ◽  
The Cost ◽  
Single Path

Photovoltaic (PV) panels account for a majority of the cost of photovoltaic thermal (PVT) panels. Bifacial silicon solar panels are attractive for PVT panels because of their potential to enhance electrical power generation from the same silicon wafer compared with conventional monofacial solar panels. This paper examines the performance of air-based bifacial PVT panels with regard to the first and second laws of thermodynamics. Four air-based bifacial PVT panels were designed. The maximum efficiencies of 45% to 63% were observed for the double-path-parallel bifacial PVT panel based on the first law of thermodynamics. Single-path bifacial PVT panel represents the highest exergy efficiency (10%). Double-path-parallel bifacial PVT panel is the second preferred design as it generates up to 20% additional total energy compared with the single-path panel. However, the daily average exergy efficiency of a double-path-parallel panel is 0.35% lower than that of a single-path panel.

Thermodynamics of a 3 — D charged rotating hairy black hole

Open Physics ◽  
2014 ◽  
Vol 12 (9) ◽  
Author(s):  
Jalil Naji ◽  
Saba Heydari ◽  
Ali Amjadi
Keyword(s):  
Phase Transition ◽  
Black Hole ◽  
Free Energy ◽  
Total Energy ◽  
Specific Heat ◽  
Three Dimensions ◽  
Study Phase ◽  
First Law Of Thermodynamics ◽  
The Stability ◽  
Hairy Black Hole

AbstractIn this paper, we consider a charged rotating black hole in three dimensions with a scalar charge, and discuss thermodynamics quantities. We find effects of the black hole parameters on the temperature, entropy, free energy, total energy and specific heat. We also investigate the stability of the black hole and study phase transition. We consider the first law of thermodynamics and find that satisfied.

scholarly journals Gravastars in a non-minimally coupled gravity with electromagnetism

2021 ◽  
Vol 81 (11) ◽  
Author(s):  
Özcan Sert ◽  
Muzaffer Adak
Keyword(s):  
Dark Energy ◽  
Exact Solutions ◽  
Free Parameter ◽  
Maxwell Model ◽  
Spherically Symmetric ◽  
Minimal Models ◽  
Coupled Models ◽  
Gravitational Fields ◽  
Gravitational Vacuum ◽  
Physical Quantities

AbstractIn this paper we investigate the gravitational vacuum stars which called gravastars in the non-minimally coupled models with electromagnetic and gravitational fields. We consider two non-minimal models and find the corresponding spherically symmetric exact solutions in the interior of the star consisting of the dark energy condensate. Our models turn out to be Einstein–Maxwell model at the outside of the star and the solutions become the Reissner–Nordström solution. The physical quantities of these models are continuous and non-singular in some range of parameters and the exterior geometry continuously matches with the interior geometry at the surface. We calculate the matter mass, the total gravitational mass, the electric charge and redshift of the star for the two models. We notice that these quantities except redshift are dependent of a subtle free parameter, k, of the model. We also remark a wide redshift range from zero to infinity depending on one free parameter, $$\beta $$ β , in the second model.

scholarly journals A note of the first law of thermodynamics by gravitational decoupling

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
Milko Estrada ◽  
Reginaldo Prado
Keyword(s):  
Phase Transition ◽  
Black Hole ◽  
Total Energy ◽  
The Other ◽  
Local Energy ◽  
Coupling Constant ◽  
First Law Of Thermodynamics ◽  
Other Hand ◽  
Total Temperature ◽  
Two Sectors

Abstract We provide a way of decoupling the first law of thermodynamics in two sectors : the standard first law of thermodynamics and the quasi first law of thermodynamics. It is showed that both sectors share the same thermodynamics volume and the same entropy. However, the total thermodynamics pressure, the total temperature and the total local energy correspond to a simple sum of the thermodynamics contributions of each sector. On the other hand, turning on the coupling constant $$\alpha $$α, the total energy, given by the Noether charge, increases proportionally to this constant. Furthermore, it is showed a simple example, where, there is a phase transition between stable/unstable black hole, and, due to the application of the decoupling, it is possible to determinate that the cause of this phase transition is the behavior of the temperature at the quasi sector.

scholarly journals Constructing Higher-Dimensional Exact Black Holes in Einstein-Maxwell-Scalar Theory

Universe ◽  
2020 ◽  
Vol 6 (9) ◽  
pp. 148
Author(s):  
Jianhui Qiu ◽  
Changjun Gao
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Black Hole Thermodynamics ◽  
Spherically Symmetric ◽  
Dilaton Gravity ◽  
Scalar Theory ◽  
First Law Of Thermodynamics ◽  
Higher Dimensional

We construct higher-dimensional and exact black holes in Einstein-Maxwell-scalar theory. The strategy we adopted is to extend the known, static and spherically symmetric black holes in the Einstein-Maxwell dilaton gravity and Einstein-Maxwell-scalar theory. Then we investigate the black hole thermodynamics. Concretely, the generalized Smarr formula and the first law of thermodynamics are derived.

scholarly journals REISSNER–NORDSTRÖM SPACE–TIME IN THE TETRAD THEORY OF GRAVITATION

2007 ◽  
Vol 16 (01) ◽  
pp. 65-79 ◽  
Author(s):  
GAMAL G. L. NASHED ◽  
TAKESHI SHIRAFUJI
Keyword(s):  
Exact Solutions ◽  
Arbitrary Function ◽  
Energy Content ◽  
Analytic Solutions ◽  
Spherically Symmetric ◽  
Theory Of Gravitation ◽  
Momentum Complex ◽  
Charged Source ◽  
Superpotential Method ◽  
Tetrad Theory

We give two classes of spherically symmetric exact solutions of the coupled gravitational and electromagnetic fields with charged source in the tetrad theory of gravitation. The first solution depends on an arbitrary function H(R,t). The second solution depends on a constant parameter η. These solutions reproduce the same metric, i.e. the Reissner–Nordström metric. If the arbitrary function which characterizes the first solution and the arbitrary constant of the second solution are set to be zero, then the two exact solutions will coincide with each other. We then calculate the energy content associated with these analytic solutions using the superpotential method. In particular, we examine whether these solutions meet the condition, which Møller required for a consistent energy–momentum complex, namely, we check whether the total four-momentum of an isolated system behaves as a four-vector under Lorentz transformations. It is then found that the arbitrary function should decrease faster than [Formula: see text] for R → ∞. It is also shown that the second exact solution meets the Møller's condition.

ENERGY AND HEAT FLUX

1995 ◽  
Vol 04 (03) ◽  
pp. 357-365
Author(s):  
J. GARIEL ◽  
N.O. SANTOS ◽  
G. LE DENMAT
Keyword(s):  
Heat Flux ◽  
General Solution ◽  
Total Energy ◽  
Weyl Tensor ◽  
Spherically Symmetric ◽  
Conformally Flat ◽  
Flat Spacetime ◽  
Spherically Symmetric Metric

The total energy in a sphere containing an isotropic shear-free conducting heat fluid is studied in the frame of a spherically symmetric metric. Firstly, we examine the role played by the heat flux. Secondly, we point out the contribution to the energy by the Weyl tensor. We obtain different formulas for the total energy, and those formulas are shown to be equivalent. We derive the general solution for a conformally flat spacetime, and give an example for a nonconformally flat spacetime.

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