The aim of this paper is to investigate the Stoneley waves in a non-homogeneous orthotropic granular medium under the influence of a gravity field. The frequency equation obtained, in the form of a sixth-order determinantal expression, is in agreement with the corresponding result when both media are elastic. The frequency equation when the gravity field is neglected has been deduced as a parti...

Stability analysis on the De Sitter universe in pure gravity theory is known to be useful in many aspects. We first show how to complete the proof of an earlier argument based on a redundant field equation. It is shown further that the stability condition applies to k 6= 0 Friedmann-Robertson-Walker spaces based on the non-redundant Friedmann equation derived from a simple effective Lagrangian....

In the context of f (R) theories of gravity, we study the cosmological evolution of scalar perturbations by using a completely general procedure. We find that the exact fourth-order differential equation for the matter density perturbations in the longitudinal gauge, reduces to a second-order equation for sub-Hubble modes. This simplification is compared with the standard (quasi-static) equatio...

Quantum geometrodynamics is canonical quantum gravity with the three-metric as the configuration variable. Its central equation is the Wheeler–DeWitt equation. Here I give an overview of the status of this approach. The issues discussed include the problem of time, the relation to the covariant theory, the semiclassical approximation as well as applications to black holes and cosmology. I concl...

We study reparametrization-invariant systems, mainly the relativistic particle and its D-dimensional extended object generalization d-brane. The corresponding matter Lagrangians naturally contain background interactions, like electromagnetism and gravity. For a dbrane that doesn’t alter the background fields, we define non-relativistic equations assuming integral sub-manifold embedding of the d...

This paper established a physical axiom system. By the axiom system we can derive important physical laws such as momentum conservation law, Newton’s second law, Newton’s law of gravity, Schrödinger equation and Maxwell’s equations, simplified existing physical theories and explain some physical phenomenons those unresolved by traditional physical theories. We can also derive Schwarzschild solu...

With applying of new proposed electromagnetic gravity Lagrangian together with Einstein-Hilbert equation not zero space curvature was derived. The curvature gives “a priory” postulate of equivalence of mass and electro-magnetic field gravity properties. The non-zero trace of energy-stress tensor of electrical field changes space curvature of gravity mass, which yields to prediction of dependenc...

The aim of this paper is to investigate the influences of rotation, magnetic field, initial stress, and gravity field on Rayleigh waves in a homogeneous orthotropic elastic medium. The government equations is solved by Lame’s potential and obtained the frequency equation which determines the velocity of Rayleigh waves, including rotation, initial stress, gravity field, and magnetic field, in a ...