Fractional Differential Equations

This chapter introduces the finite element method (FEM) as a tool for solution of classical electromagnetic problems. Although we discuss the main points in the application of the finite element method to electromagnetic design, including formulation and implementation, those who seek deeper understanding of the finite element method should consult some of the works listed in the bibliography section.

Introduction to the Finite Element Method

In this problem, we study the effect of variable thermal conductivity, which depend on temperature in the context of Photothermal diffusion (PTD). The PTD process is applied with thermoelasticity theory in chemical action. The model introduced describes the interaction between elastic-thermal-plasma waves, which based on the material properties of semiconductor elastic medium. The Laplace transform is used to solve the governing equations in one dimension of a thin circular plate. Some new constant will be appearing during the theoretical discussion. The mechanical forces and thermal loads are applied on the free surface of semiconductor to obtain the physical fields. The complete solutions in time domain are observed by using a numerical approximation method. The physical fields with some comparsions are presented analytically and graphically.

Effect of Variable Thermal Conductivity during the Photothermal Diffusion Process of Semiconductor Medium

In this article, theoretical discussions for a novel mathematical-physical Photothermal diffusion (PTD) model in the generalized thermoelasticity theory with photothermal processes and chemical action are introduced. The mean idea of this model depends on the interaction between quasi-particles (plasma waves) that depends on the kind of the used materials, the mechanical forces acting on the surface, the generalized thermo and mass diffusion (due to coupling of temperature fields with thermal waves and chemical potential) and the elastic waves. The one dimensional Laplace transforms is used to obtain the exact solution for some physical and chemical quantities for a thin circular plate of a semiconducting polymer nanocomposite such as silicon (Si). New variables are deduced and discussed. The obtained results of the physical quantities are presented analytically and illustrated graphically with some important applications.

A novel model of photothermal diffusion (PTD) for polymer nano-composite semiconducting of thin circular plate

In this paper, we consider a one dimensional problem of waves in a thermoelastic infinite medium with a spherical cavity. We are concerned with the study a new model of fractional order heat conduction law for a spherical cavity of a semiconductor medium. The governing equations are solved under the effect of the theory of coupled plasma, elastic, thermal waves through a photothermal process. The inner surface of the cavity is taken traction free with thermal shock. Time-dependence is removed by Laplace transform technique to governing equations. This method has been used to get the exact expression of some physical quantities, thermal activation coupling parameters and illustrated graphically.

A novel solution of fractional order heat equation for photothermal waves in a semiconductor medium with a spherical cavity

In this work, a new theory of thermoelasticity associated with two relaxation times is derived using the methodology of fractional calculus. The theories of coupled thermoelasticity and of generalized thermoelasticity (Green–Lindsay Model) with two relaxation times follow as limiting cases. A uniqueness theorem and a reciprocity theorem for this model are derived. A variational principle theorem is obtained.

Generalized Fractional Thermoelasticity Associated with Two Relaxation Times

Here, this work is concerned with some different one-dimensional (1D) problems of distribution of the thermal stresses and temperature in fractional generalized thermoelastic material, as follows: (i) 1D problem for a half-space of elastic material in the presence of heat sources has been solved by using Laplace transform and state space techniques; and (ii) 1D problem of distribution of thermal stresses and temperature in infinite medium with a spherical cavity subjected to a sudden change in the temperature of its internal boundary, which is assumed to be traction free, has been solved by Laplace transform and direct approach techniques. In the preceding problems, the numerical results for dimensionless variable fields are given and illustrated graphically. According to the numerical results, some comparisons have been shown in figures to estimate the effect of the fractional derivative parameter α about the new theory on all variable fields and discussion has been established for a copper-like ...

M. Abdou

Papers

Generalized Fractional Thermoelasticity Associated with Two Relaxation Times

1D applications on fractional generalized thermoelasticity associated with two relaxation times