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3,338 results on '"Field equation"'

1. Thermodynamics evaluation in Einstein–Gauss–Bonnet gravity like black holes.

Author

Ali, Riasat, Tiecheng, Xia, Aounallah, Houcine, and Babar, Rimsha

Abstract

From D-dimensional black holes, we investigate the Hawking radiation of charged boson particles from charged black holes without and with quantum gravity. We apply the field equation and WKB approximation to solve the Einstein–Gauss–Bonnet gravity like spacetime and obtain the tunneling radiation from charged black holes using complex path integration. We also calculate the temperature of the radiation from these black holes using the tunneling probability of outgoing particles without and with the influence of quantum gravity. We also look into the entropy and heat capacity of well-known thermodynamic properties for the geometry under consideration. It is concluded that the D dimension like black holes is stable or unstable under Einstein–Gauss–Bonnet gravity. [ABSTRACT FROM AUTHOR]

Published
2024
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5. Peridynamic Theory

Author

Madenci, Erdogan, Anicode, Sundaram Vinod Kumar, Zhang, Yanan, Madenci, Erdogan, Anicode, Sundaram Vinod Kumar, and Zhang, Yanan

Published
2024
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7. Economic design of sleeve rotor induction motor using rotor ends.

Author

Daif, Omar S., Abd Raouf, M. Helmy, Esmaeel, Mohamed Adel, and Kotb, Abd Elsamie B.

Subjects
INDUCTION machinery, AIR gap flux, INDUCTION motors, MAXWELL equations, FORCE density, ROTORS, SKIN effect
Abstract

In this paper, the field analysis of the sleeve rotor induction motor (IM) is carried out taking the rotor ends into consideration. Here, the field system equations are derived using the cylindrical model with applying Maxwell's field equations. It is expected that, both starting and maximum torques will increase with taking the rotor ends than that without rotor ends. A simple model is used to establish the geometry of the rotor ends current density and to investigate the air gap flux density. The magnetic flux is assumed to remain radially constant through the very small air gap length between the sleeve and stator surfaces. Variation of the field in the radial direction is ignored and the skin effect in the axial direction is considered. The axial distributions of the air gap flux density, the sleeve current density components and the force density have been determined. The motor performance is carried out taking into account the effects of the rotor ends on the starting and normal operations. The sleeve rotor resistance and leakage reactance have been obtained in terms of the cylindrical geometry of the machine. These equivalent circuit parameters have been calculated and plotted as functions of the motor speed with and without the rotor ends. [ABSTRACT FROM AUTHOR]

Published
2022
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8. Lagrangian Formulation of General Relativity

Author

Vecchiato, Alberto, Ashby, Neil, Series editor, Brantley, William, Series editor, Deady, Matthew, Series editor, Fowler, Michael, Series editor, Hjorth-Jensen, Morten, Series editor, Inglis, Michael, Series editor, Klose, Heinz, Series editor, Sherif, Helmy, Series editor, and Vecchiato, Alberto

Published
2017
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9. Classical Physics, Fundamental Principles, and Lagrangian Approach

Author

Vecchiato, Alberto, Ashby, Neil, Series editor, Brantley, William, Series editor, Deady, Matthew, Series editor, Fowler, Michael, Series editor, Hjorth-Jensen, Morten, Series editor, Inglis, Michael, Series editor, Klose, Heinz, Series editor, Sherif, Helmy, Series editor, and Vecchiato, Alberto

Published
2017
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10. Applications

Author

Vecchiato, Alberto, Ashby, Neil, Series editor, Brantley, William, Series editor, Deady, Matthew, Series editor, Fowler, Michael, Series editor, Hjorth-Jensen, Morten, Series editor, Inglis, Michael, Series editor, Klose, Heinz, Series editor, Sherif, Helmy, Series editor, and Vecchiato, Alberto

Published
2017
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11. Beyond General Relativity

Author

Vecchiato, Alberto, Ashby, Neil, Series editor, Brantley, William, Series editor, Deady, Matthew, Series editor, Fowler, Michael, Series editor, Hjorth-Jensen, Morten, Series editor, Inglis, Michael, Series editor, Klose, Heinz, Series editor, Sherif, Helmy, Series editor, and Vecchiato, Alberto

Published
2017
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12. A Short Introduction to Field Theories and Variational Approach

Author

Vecchiato, Alberto, Ashby, Neil, Series editor, Brantley, William, Series editor, Deady, Matthew, Series editor, Fowler, Michael, Series editor, Hjorth-Jensen, Morten, Series editor, Inglis, Michael, Series editor, Klose, Heinz, Series editor, Sherif, Helmy, Series editor, and Vecchiato, Alberto

Published
2017
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13. Geons in Palatini Theories of Gravity

Author

Olmo, Gonzalo J., Rubiera-Garcia, Diego, van Beijeren, Henk, Series editor, Blanchard, Philippe, Series editor, Busch, Paul, Series editor, Coecke, Bob, Series editor, Dieks, Dennis, Series editor, Dittrich, Bianca, Series editor, Dürr, Detlef, Series editor, Durrer, Ruth, Series editor, Frigg, Roman, Series editor, Fuchs, Christopher, Series editor, Ghirardi, Giancarlo, Series editor, Giulini, Domenico J. W., Series editor, Jaeger, Gregg, Series editor, Kiefer, Claus, Series editor, Landsman, Nicolaas P., Series editor, Maes, Christian, Series editor, Murao, Mio, Series editor, Nicolai, Hermann, Series editor, Petkov, Vesselin, Series editor, Ruetsche, Laura, Series editor, Sakellariadou, Mairi, Series editor, van der Merwe, Alwyn, Series editor, Verch, Rainer, Series editor, Werner, Reinhard F., Series editor, Wüthrich, Christian, Series editor, Young, Lai-Sang, Series editor, and Lobo, Francisco S. N., editor

Published
2017
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15. An exact super dense star model on spheroidal space-time.

Author

Naren Babu, O. V., Hemalatha, R., and Sabu, M. C.

Subjects
*EINSTEIN field equations, *NEUTRON stars, *STARS, *DARK energy, *SCHWARZSCHILD black holes, *EQUATIONS
Abstract

We consider the 3-dimensional space with t 1 = constant in a super dense star which is spheroidal. We report a class of static spherically symmetric physically viable models based on a particular actual solution of Einsteins field equations. The models of the class admit densities of the order of 2 × 10 14 gm cm − 3 , radii of the order of a few kilometers and maximum masses up to about three times the solar mass. [ABSTRACT FROM AUTHOR]

Published
2020
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16. Local Generalization of Pauli's Theorem.

Author

Marchuk, N. G. and Shirokov, D. S.

Subjects
*CLIFFORD algebras, *SIMILARITY transformations, *PARTIAL differential equations, *SMOOTHNESS of functions, *GENERALIZATION
Abstract

Generalized Pauli's theorem, proved by D. S. Shirokov for two sets of anti- commuting elements of a real or complexified Clifford algebra of dimension 2n, is extended to the case, where both sets of elements depend smoothly on points of Euclidean space of dimension r. We prove that in the case of even n there exists a smooth function such that two sets of Clifford algebra elements are connected by a similarity transformation. All cases of connection between two sets are considered in the case of odd n. Using the equation for the spin connection of general form, it is shown that the problem of the local Pauli's theorem is equivalent to the problem of existence of a solution of some special system of partial differential equations. The special cases n = 2, r = 1 and n = 2, r = 1 with simpler solution of the problem are considered in detail. [ABSTRACT FROM AUTHOR]

Published
2020

18. The Basics of the Neoclassical Theory of Charges with Spin 1/2

Author

Babin, Anatoli, Figotin, Alexander, Beiglböck, Wolf, Series editor, Chrusciel, Piotr, Series editor, Eckmann, Jean-Pierre, Series editor, Grosse, Harald, Series editor, Kupiainen, Antti, Series editor, Löwen, Hartmut, Series editor, Loss, Michael, Series editor, Nekrasov, Nikita A., Series editor, Salmhofer, Manfred, Series editor, Smirnov, Stanislav, Series editor, Takhtajan, Leon, Series editor, Yngvason, Jakob, Series editor, Ohya, Masanori, Series editor, Babin, Anatoli, and Figotin, Alexander

Published
2016
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19. Introduction

Author

Babin, Anatoli, Figotin, Alexander, Beiglböck, Wolf, Series editor, Chrusciel, Piotr, Series editor, Eckmann, Jean-Pierre, Series editor, Grosse, Harald, Series editor, Kupiainen, Antti, Series editor, Löwen, Hartmut, Series editor, Loss, Michael, Series editor, Nekrasov, Nikita A., Series editor, Salmhofer, Manfred, Series editor, Smirnov, Stanislav, Series editor, Takhtajan, Leon, Series editor, Yngvason, Jakob, Series editor, Ohya, Masanori, Series editor, Babin, Anatoli, and Figotin, Alexander

Published
2016
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23. Einstein’s Field Equations, Their Special Mathematical Structure, and Some of Their Remarkable Physical Predictions

Author

Pfister, Herbert, King, Markus, Englert, Berthold-Georg, Series editor, Hänggi, Peter, Series editor, Hillebrandt, Wolfgang, Series editor, Jones, Richard A L, Series editor, von Löhneysen, H., Series editor, Raimond, Jean-Michel, Series editor, Salmhofer, Manfred, Series editor, Theisen, Stefan, Series editor, Vollhardt, Dieter, Series editor, Longair, Malcolm S., Series editor, Rubio, Angel, Series editor, Hjorth-Jensen, Morten, Series editor, Wells, James D., Series editor, Lewenstein, Maciej, Series editor, Zank, Gary P, Series editor, Pfister, Herbert, and King, Markus

Published
2015
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28. The generalized fractional order of the Chebyshev functions on nonlinear boundary value problems in the semi-infinite domain

Author

Parand Kourosh and Delkhosh Mehdi

Subjects
generalized fractional order of the chebyshev functions, unsteady isothermal flow of a gas equation, third grade fluid equation, blasius equation, field equation, semi-infinite domain, 02.60.lj, 02.70.jn, 34b15, 34b40, 74s25, 34l30, Engineering (General). Civil engineering (General), TA1-2040
Abstract

A new collocation method, namely the generalized fractional order of the Chebyshev orthogonal functions (GFCFs) collocation method, is given for solving some nonlinear boundary value problems in the semi-infinite domain, such as equations of the unsteady isothermal flow of a gas, the third grade fluid, the Blasius, and the field equation determining the vortex profile. The method reduces the solution of the problem to the solution of a nonlinear system of algebraic equations. To illustrate the reliability of the method, the numerical results of the present method are compared with several numerical results.

Published
2017
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31. Space-Time and Gravitation

Author

Romero, Gustavo E., Vila, Gabriela S., Englert, Berthold-Georg, Series editor, Frisch, Uriel, Series editor, Hänggi, Peter, Series editor, Hillebrandt, Wolfgang, Series editor, Jones, Richard A L, Series editor, von Löhneysen, H., Series editor, Raimond, Jean-Michel, Series editor, Salmhofer, Manfred, Series editor, Sornette, Didier, Series editor, Theisen, Stefan, Series editor, Vollhardt, Dieter, Series editor, Weise, Wolfram, Series editor, Longair, Malcolm S., Series editor, Rubio, Angel, Series editor, Hjorth-Jensen, Morten, Series editor, Pinton, Jean-Francois, Series editor, Wells, James D., Series editor, Romero, Gustavo E., and Vila, Gabriela S.

Published
2014
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36. Semi-symmetric connection formalism for unification of gravity and electromagnetism.

Author

Fasihi-Ramandi, Gh.

Subjects
*UNIFIED field theories, *ELECTROMAGNETISM, *MAXWELL equations, *GRAVITY, *EINSTEIN field equations
Abstract

In this paper, the notion of semi-symmetric connections provides us a good apparatus to establish a unified field theory. The field equations are derived from an action principle which is formed naturally by the scalar curvature of the semi-symmetric connection. The derived equations contain the Einstein and Maxwell equations in vacuum, simultaneously. [ABSTRACT FROM AUTHOR]

Published
2019
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37. A Study of Einstein Field Equation.

Author

WANG Xue-ren

Subjects
EINSTEIN field equations, LINEAR acceleration, GENERAL relativity (Physics)
Abstract

Copyright of Journal of Harbin University of Science & Technology is the property of Journal of Harbin University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2019
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38. Higher-dimensional black hole solutions with scalar hair and dilaton field and toroidal horizons and interior solution

Author

Yahya Younesizadeh and Younes Younesizadeh

Subjects
Physics, Black hole, General Relativity and Quantum Cosmology, Gravity (chemistry), Toroid, Field (physics), Scalar (mathematics), General Physics and Astronomy, Dilaton, Field equation, Mathematical physics
Abstract

In this study, we investigate black hole solutions with toroidal horizons in scalar hair and dilaton gravity. First, we obtain the field equations in n-dimensions. Then, we propose different models (ansatz) and find the exact solutions for these types of ansatzs. These solutions are not asymptotically (anti) de Sitter or flat, except in one special case. We also show that the BTZand BTZ-like solutions emerge from some of these solutions as a special case. We also show that when the event horizon radius increases, the temperature will be the same in various dimensions. The only difference is noticeable near the origin (this statement is clear from the figures). For these solutions, we obtained a new version of the Smarr formula. In addition, we show that the presence of the scalar field makes the black holes more stable near the origin, except for the BTZ case. In general, the presence of a scalar field is an important factor in black hole stability investigations. In the critical behavior analysis, we find that there is no evidence to show the existence of P-V criticality. Here, we present a class of interior solutions corresponding to the solution in a scalar hair gravity exterior. The solution obtained in the linear case was regular and well-behaved at the stellar interior.

Published
2022

39. On One Controllability of the Schrödinger Equation as Coupled with the Atomic-Level Mannesmann Effect

Author

Tomáš Perna

Subjects
controllability, schrödinger equation, field equation, cyclic group, alternating group, tunnelling, Mathematics, QA1-939
Abstract

In this paper we outline a certain way of understanding of macroscopically uncontrollable emergence of the so called Mannesmann effect by means of its induced controllable quantum-mechanical background. In other words, we factually present a modus operandi of how to avoid macroscopic models of specific atomic-level cavity origin based consequently on a classical fracture mechanics theory. Under such circumstances, the target solution of the controllable microscopic model cannot be determined, since it can obviously arise only as a macroscopic state of the structurally disturbed rolled metal semi-product during the Mannesmann process. We obtain this irrelevance of the target solution, using a very special kind of control of the famous Schrödinger equation employed as a fundamental model equation here. We show contextually that such control follows from some very elementary aspects of the group theory conditioning a physical meaning of the Schrödinger equation written in a controllable form. We specially emerge primary cyclic groups of symmetry of special solutions to the Schrödinger equation. Their imaginary part is given by a control satisfying the Klein-Gordon equation which can be driven (through a specific avoidance of the cyclic group Z4) into a connection with the characteristic series of primary cyclic groups and/or torsion groups respectively. We obtain a physically controllable special results representing a strange correspondence between a certain LET (Linear Energy Transfer) and “quantum-like” tunnelling interpreted for some “everyday” objects, particularly for the considered Mannesmann piercing process with a torsion known from metallurgy. The process violations are shown and further reflected via a standard finite element method (FEM) simulation.

Published
2020
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44. Cosmology

Author

Das, Anadijiban, DeBenedictis, Andrew, Das, Anadijiban, and DeBenedictis, Andrew

Published
2012
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50. Stellar modeling with the Einstein-Maxwell field equations via gravitational decoupling

Author

Neeraj Pant, Satyanarayana Gedela, and Ravindra K. Bisht

Subjects
Physics, General Physics and Astronomy, Decoupling (cosmology), Maxwell field, 01 natural sciences, 010305 fluids & plasmas, Gravitation, symbols.namesake, Neutron star, Classical mechanics, 0103 physical sciences, symbols, Einstein, 010306 general physics, Anisotropy, Field equation
Abstract

The aim of the present paper is to find an exact anisotropic and charged version of the well-known Heintzmann interior solution [Z. Phys. 228 (1969) 489] in a space-time via the minimal geometric deformation approach to gravitational decoupling (MGD-decoupling). Further, we discuss the physical cogency of the solution for the coupled system by performing several physical tests. The obtained model represents the neutron star 4U1608-52 and fulfills all the requirements in order to be a well behaved physical solution to Einstein-Maxwell’s field equations.

Published
2021

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