Samia M. Said

Influence of gravity on generalized magneto-thermoelastic medium for three-phase-lag model

The three-phase-lag model and Green-Naghdi theory without energy dissipation are applied to study the effect of the gravity field and a magnetic field on a wave propagation in a generalized thermoelastic problem for a medium with an internal heat source that is moving with a constant speed. The medium is a homogeneous isotropic thermoelastic in the half-space. The exact expressions of the displacement components, temperature, and stress components are obtained by using normal mode analysis. Numerical results for the field quantities are given in the physical domain and illustrated graphically in the absence and presence of a magnetic field as well as the gravity field.

The Effect of Rotation on a Fiber-Reinforced Medium under Generalized Magneto-Thermoelasticity with Internal Heat Source

In the present article, we discussed the transient waves caused by a line heat source with a uniform velocity inside a rotating half-space fiber-reinforced thermoelastic media permeated into a uniform magnetic field. The formulation of the problem is applied under the coupled theory (CD), Green-Lindsay (G-L) theory, and Lord-Shulman (L-S) theory. The normal mode analysis is used to obtain expressions for the temperature, displacement components, and thermal stresses. Numerical results are given and illustrated graphically. A comparison is made with the results predicted by three theories in the presence and absence of magnetic field and rotation as well as fiber-reinforced.

Application of the Second Born Approximation to Excitation of Hydrogen Atoms by Protons and Antiprotons Impact

We present and compare total cross sections for excitation in collisions of protons and antiprotons with hydrogen atoms in the 2s state. Calculations are performed in the framework of the second Born approximation, in the energy range of 5-1000keV. We apply the usual approach of the second Born approximation, which approximates the summation raised by retaining few terms, as well as another approach approximates all energies corresponding to the intermediate states to that corresponding to the initial state. The annihilation effect in the case of the antiproton collision is investigated. We compare the results with the previous theoretical calculations.

A fiber-reinforced thermoelastic medium with an internal heat source due to hydrostatic initial stress and gravity for the three-phase-lag model

Purpose The purpose of this paper is to investigate the effect of a hydrostatic initial stress and the gravity field on a fiber-reinforced thermoelastic medium with an internal heat source that is moving with a constant speed. Design/methodology/approach A general model of the equations of the formulation in the context of the three-phase-lag model and Green-Naghdi theory without energy dissipation. Findings The exact expressions for the displacement components, force stresses, and the thermal temperature for the thermal shock problem obtained by using normal mode analysis. Originality/value A comparison made between the results of the two models for different values of a hydrostatic initial stress as well as an internal heat source. Comparisons also made with the results of the two models in the absence and presence of the gravity field as well as the reinforcement.

Two-temperature generalized magneto-thermoelastic medium for dual-phase-lag model under the effect of gravity field and hydrostatic initial stress

Purpose – The dual-phase-lag (DPL) model and Lord-Shulman theory with one relaxation time are applied to study the effect of the gravity field, the magnetic field, and the hydrostatic initial stress on the wave propagation in a two-temperature generalized thermoelastic problem for a medium with an internal heat source that is moving with a constant speed. The paper aims to discuss this issue. Design/methodology/approach – The exact expressions of the considered variables are obtained by using normal mode analysis. Findings – Numerical results for the field quantities are given in the physical domain and illustrated graphically in the absence and presence of the gravity field as well as the magnetic field. Comparisons are made between the results of the two different models with and without temperature dependent properties and for two different values of the hydrostatic initial stress. A comparison is also made between the results of the two different models for two different values of the time. Originalit...

Influence of the mechanical force and the magnetic field on fibre-reinforced medium for three-phase-lag model

Abstract A new theory of generalised thermoelasticity has been constructed by taking into account the deformation of a fibre-reinforced isotropic thermoelastic medium. A general model of the equations of the formulation in the context of the three-phase-lag model and Green–Naghdi theory without energy dissipation theory are applied to study the influence of a mechanical force, temperature dependent and a magnetic field on the wave propagation within a fibre-reinforced isotropic thermoelastic medium. The exact expressions of the displacement components, temperature and stress components are obtained using normal mode analysis. The variations of the considered variables with the horizontal distance are illustrated graphically for different values of a mechanical force. Comparisons are made between the results of the two theories in the presence and absence of a magnetic field as well as temperature-dependent properties.

Effect of gravity field and moving internal heat source on a 2-D problem of thermoelastic fiber-reinforced medium: Comparison of different theories

ABSTRACT A new fiber-reinforced model has been constructed by taking into account the deformation of a generalized thermoelastic medium with internal heat source. A general model of the equations of the formulation in the context of the Lord–Shulman theory that includes one relaxation time and Green–Lindsay theory with two relaxation times, as well as the classical dynamical coupled theory, is applied to study the influence of gravity and reinforcement on the total deformation of a thermoelastic medium. The normal mode analysis is used to obtain the exact expressions for the physical quantities. The variations of the considered variables with the horizontal distance are illustrated graphically. Comparisons are made with the results in the three theories in the presence and absence of reinforcement, gravity, and moving internal heat source.

Influence of the rotation on a generalized magneto-thermoelastic medium for three-phase-lag model

Purpose – The purpose of this paper is to investigate the effect of rotation and a magnetic field on the wave propagation in a generalized thermoelastic problem for a medium with an internal heat source that is moving with a constant speed. Design/methodology/approach – The formulation is applied to a generalized thermoelastic problem based on the three-phase-lag model and Green-Naghdi theory without energy dissipation. The medium is a homogeneous isotropic thermoelastic in the half-space. Findings – The exact expressions of the displacement components, temperature, and stress components are obtained by using normal mode analysis. Originality/value – Comparisons are made with the results predicted by the two models in the absence and presence of a magnetic field as well as a rotation. A comparison also is made with the results predicted by the two models for two different values of an internal heat source.