seismic tomography is an imaging technique which creates maps of subsurface elastic properties such as p/s wave velocity, density and attenuation, based on observed seismograms and use of sophisticated inversion algorithms. amongst different acquisition geometries, seismic cross-hole tomography has a special position in geophysical surveys with many applications in hydrocarbons, coal and other ...

We will present a detailed investigation of intersubband transitions process in core-multi shells quantum dots. The confined wave functions and eigenenergies of electrons in quantum dots have been calculated under the effective-mass approximation by solving a three-dimensional Schrodinger equation. Excellent dependence is found between size effects, time relaxation and degenerate four wave mixi...

We will present a detailed investigation of intersubband transitions process in core-multi shells quantum dots. The confined wave functions and eigenenergies of electrons in quantum dots have been calculated under the effective-mass approximation by solving a three-dimensional Schrodinger equation. Excellent dependence is found between size effects, time relaxation and degenerate four wave mixi...

The purpose of this work is to present and analyze the results of numerical simulations related to the application of three different mathematical models in the acoustic seismic wave propagation in which only compressional waves (P-waves) are contemplated. And present the results of an investigation about how these wave equation implementations can influence the amplitudes of a migrated section...

Atmospheric gravity waves play fundamental roles in a broad-range of dynamical processes extending throughout the Earth’s neutral atmosphere and ionosphere. In this paper, we present a modified form for the acoustic-gravity wave equation and its dispersion relationships for a compressible and non-stationary atmosphere in hydrostatic balance. Importantly, the solutions have been achieved without...

This paper describes the use of genetic algorithms (GAs) for the optimal design of phononic bandgaps in periodic elastic two-phase media. In particular, we link a GA with a computational finite element method for solving the acoustic wave equation, and find optimal designs for both metal–matrix composite systems consisting of Ti/SiC, and H2O-filled porous ceramic media, by maximizing the relati...

The existence of acoustic, Rayleigh-Bloch modes in the vicinity of a one-dimensional periodic array of rigid, axisymmetric structures is established with the use of a variational principle. Axisymmetric modes at frequencies below the cut-off frequency are shown to exist for all piecewise smooth structures and non-axisymmetric modes are found for a class of structures whose radial dimension is s...

This study investigates the influence of blood flow on temperature distribution during high-intensity focused ultrasound (HIFU) ablation of liver tumors. A three-dimensional acoustic-thermal-hydrodynamic coupling model is developed to compute the temperature field in the hepatic cancerous region. The model is based on the nonlinear Westervelt equation, bioheat equations for the perfused tissue ...

In the forward problem of acoustic tomography, one needs to be able to implement the wave equation numerically and find the values at each receiver point. In this research the possible solutions are studied and their properties are discussed and one proposed algorithm is selected as the satisfactory result in the sense of less numerical dispersion. Stability conditions for these algorithms are ...