Der vorliegende Band enthált sechs Beitrage, in denen punktuell und exemplarisch der Stand der Forschung beleuchtet wird. Ein Beitrag von Codling und Frasinski beschreibt in erster Linie Experimente zum noch wenig verstandenen Phânomen der dissoziativen Ionisation von Molekülen, bei dem diese in einem intensiven Laserfeld mehrere Elektronén verlieren und in Ionen mit hoher kinetischer Energie zerfallen. Ein wesentlicher Teil dieses Beitrags widmet sich einer von den Autoren entwickelten Auswertungstechnik, welche die Korrelationen zwischen den Fiugzeiten emittierter Ionen und Elektronén sichtbar macht. Es folgen drei Beitrage zur Théorie. Schmelcher und Cederbaum beschreiben Effekte starker statischer Felder, die nur dann zu verstehen sind, wenn die Nicht-Separation der Schwerpunktsbewegung im auBeren Magnetfeld korrekt beriicksichtigt wird. Dies fiihrt

Extended Irreversible Thermodynamics

A new nonlocal theory of generalized thermoelastic materials with voids based on Eringen’s nonlocal elasticity and Caputo fractional derivative is established. The one-dimensional form of the above...

Nonlocal theory of thermoelastic materials with voids and fractional derivative heat transfer

A three-dimensional model of the generalized thermoelasticity without energy dissipation under temperature-dependent mechanical properties is established. The modulus of elasticity is taken as a linear function of the reference temperature. The resulting formulation in the context of Green and Naghdi model II is applied to a half-space subjected to a time-dependent heat source and traction free surface. The normal mode analysis and eigenvalue approach techniques are used to solve the resulting non-dimensional coupled equations. Numerical results for the field quantities are given in the physical domain and illustrated graphically. The results are also compared to results obtained in the case of temperature-independent modulus of elasticity.

Eigenvalue approach in a three-dimensional generalized thermoelastic interactions with temperature-dependent material properties

This article highlights on the study of coupled plasma, thermal and elastic waves within an orthotropic infinite semiconducting medium in context of photothermal transport process having a spherica...

Photo-thermo-elastic wave propagation in an orthotropic semiconductor with a spherical cavity and memory responses

The purpose of this study is to provide a method to investigate the effects of thermal relaxation times in a poroelastic material by using the finite element method. The formulations are applied under the Green and Lindsay model, with four thermal relaxation times. Due to the complex governing equation, the finite element method has been used to solve these problems. All physical quantities are presented as symmetric and asymmetric tensors. The effects of thermal relaxation times and porosity in a poro-thermoelastic medium are studied. Numerical computations for temperatures, displacements and stresses for the liquid and the solid are presented graphically.

https://www.mdpi.com/2073-8994/12/3/488/pdf

A GL Model on Thermo-Elastic Interaction in a Poroelastic Material Using Finite Element Method

The Lord–Shulman (LS) model of generalized thermoelasticity and the Eringen's model of nonlocal elasticity are used to formulate the new constitutive relations and the field equations. The propagation of plane thermoelastic waves are then probed in a homogeneous isotropic nonlocal thermoelastic solid by employing this new model. We found two sets of the coupled longitudinal waves and one independent shear‐type wave. All these waves are found to be dispersive and attenuating in nature in the presence of nonlocality in the medium. We found that the shear‐type wave faces a critical frequency, while the coupled longitudinal waves may face critical frequency conditionally. A reflection of thermoelastic waves at a stress‐free thermally insulated and isothermal boundary of a thermoelastic half‐space are also considered in case of incident coupled longitudinal thermoelastic wave. The amplitude ratios of the reflected waves to that incident wave are determined analytically. For a particular model, various graphs are plotted to analyze the behavior of the phase speeds, attenuation coefficients and reflection coefficients. To investigate the effect of elastic nonlocal parameter on the variations of phase speeds, attenuation coefficients and amplitude ratios of the reflected waves are presented graphically. Some interesting results are noticed: All the waves are detected to be influenced by the nonlocality of the medium. The longitudinal waves are influenced by the thermal parameters but the shear‐type wave is independent of the thermal effect. Moreover the presence of elastic nonlocality reduces the classical shear‐type wave speed.

Plane waves in nonlocal generalized thermoelasticity

This paper demonstrates the reflection phenomenon of the magneto-thermoelastic plane waves from a stress-free surface of a homogeneous, isotropic, thermally and electrically conducting solid half-space. We employ the generalized thermoelasticity model with memory-dependent derivative (MDD) for this study. We find that three basic plane waves consisting of two sets of coupled longitudinal waves and one independent shear type wave may travel with distinct speeds in the medium. The speeds of the coupled longitudinal waves are plotted graphically to predict a comparison for the MDD and Lord–Shulman models. At last, for an appropriate material, the reflection coefficients are computed numerically and presented graphically with the angle of incidence of the incident (vertically polarized) shear type wave and the obtained results are explained.

Memory response in plane wave reflection in generalized magneto-thermoelasticity

A novel model of the generalized magneto-thermoelasticity with two-temperature theory is investigated. The memory-depended derivative (MDD) during the excitation processes by pulsed laser is establ...

Memory-dependent derivatives (MDD) of magneto-thermal-elastic waves excited by laser pulses for two-temperature theory

We explore the analysis of exact three-dimensional free vibrations of visco-thermoelastic solid cylinder, which has been considered at a uniform temperature and undeformed initially in the framewor...

Nantu Sarkar

Papers

Plane waves in nonlocal generalized thermoelasticity

Memory response in plane wave reflection in generalized magneto-thermoelasticity

Memory-dependent derivatives (MDD) of magneto-thermal-elastic waves excited by laser pulses for two-temperature theory

Analysis of three–dimensional free vibrations of isotropic visco-thermoelastic solid cylinder with two relaxation time parameters

Waves in nonlocal thermoelastic solids of type III