12,331 research outputs found
Temporal nature of plasticity in the design of materials
A full spectrum of materials responses to dynamic loading and observed temporal effects of plasticity from a united viewpoint are analyzed. The relaxation model of plasticity with characteristic time idea is capable to effectively predict the instability of the stress-strain dependencies on strain rates. It is shown that empirical models cannot simultaneously simulate the appearance and disappearance of the yield drop unlike the relaxation model of plasticity presented in the paper
Maeda-Dadhich Solutions as Real Black Holes
A four-dimensional static Schwarzschild-like solution obtained in [3]-[6] in
the frames of the Einstein-Gauss-Bonnet gravity at the Kaluza-Klein split is
analyzed. The matter in these solutions is created by auxiliary dimensions. The
main goal of our work is to study physically sensible characteristics, which
could be observable. Study of the perturbed equations demonstrates their
stability under linear perturbations. The specific combinations of the
parameters, permitting to construct black hole-like objects with one or two
horizons or naked singularities are determined. Stable orbits of test particles
around these black holes are presented. We show the exotic thermodynamical
properties of the solution, when the Hawking evaporation law has the behavior
opposite to usual one in General Relativity
A note on the Deser-Tekin charges
Perturbed equations for an arbitrary metric theory of gravity in
dimensions are constructed in the vacuum of this theory. The nonlinear part
together with matter fields are a source for the linear part and are treated as
a total energy-momentum tensor. A generalized family of conserved currents
expressed through divergences of anti-symmetrical tensor densities
(superpotentials) linear in perturbations is constructed. The new family
generalizes the Deser and Tekin currents and superpotentials in quadratic
curvature gravity theories generating Killing charges in dS and AdS vacua. As
an example, the mass of the -dimensional Schwarzschild black hole in an
effective AdS spacetime (a solution in the Einstein-Gauss-Bonnet theory) is
examined.Comment: LATEX, 7 pages, no figure
The Schwarzschild black hole as a point particle
The description of a point mass in general relativity (GR) is given in the
framework of the field formulation of GR where all the dynamical fields,
including the gravitational field, are considered in a fixed background
spacetime. With the use of stationary (not static) coordinates non-singular at
the horizon, the Schwarzschild solution is presented as a point-like field
configuration in a whole background Minkowski space. The requirement of a
stable -causality stated recently in [J.B.Pitts and W.C.Schieve, Found.
Phys., v. 34, 211 (2004)] is used essentially as a criterion for testing
configurations.Comment: LATEX, 8 pages, no figure
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