Search

In this article, a model of two dimensional problem of generalized thermoelasticity for a homogeneous isotropic nonlocal microstretch saturated porous medium with variable thermal conductivity is established. The enunciation is applied to generalized thermoelasticity theory based on Moore-Gibson-Thompson heat conduction model. The formulae for amplitude ratios and energy ratios corresponding to various reflected waves have been presented, when a set of coupled waves strikes obliquely at the boundary surface of the assumed model. The numerical values of modulus of reflection coefficients are presented graphically to depict the effects of microstretch parameter, porosity, variable thermal conductivity, and non local parameter. Expressions of energy ratios have also been obtained in explicit form and are shown graphically as functions of angle of incidence. It has been verified that during the reflection phenomenon, the sum of energy ratios is equal to unity at each angle of incidence. Results of some earlier workers have been deduced from the present formulation. [ABSTRACT FROM AUTHOR]

In this paper, we present certain complete solutions in the dilatation theory of elasticity. This model can be derived as a special case of Eringen's linear theory of microstretched elastic solids when microrotations are absent. It is also a version of the theory of materials with voids. The dilatation theory can be considered the simplest theoretical model of microstructured materials and is suitable for investigating various phenomena that occur in engineering, geomechanics, and biomechanics. We establish three complete solutions to the displacement equations of equilibrium that are the counterpart of the Green–Lamé (GL), Boussinesq–Papkovich–Neuber (BPN), and Cauchy–Kowalevski–Somigliana (CKS) solutions of classical elasticity. The links between these BPN and CKS solutions are established. Then, we present a representation of the BPN solution in the case of axisymmetry. The results presented here are useful for solving axisymmetric problems in semi-infinite and infinite domains. [ABSTRACT FROM AUTHOR]

All research is a social construction. In this paper, we work to illuminate those moments of co-constructed meaning by taking readers on a "behind the scenes" tour of a collaborative research project that explored educator relationships. We describe our priorities in and care for participant recruitment and scheduling, our post-hoc reflections on the differences in emotional tenor between interviews and focus groups, and our own roles and positionalities within the data collection and analysis process. Action-items are recommended for other group-based qualitative studies to humanize the process of research and prioritize moments of agency, trust, and connection among participants. [ABSTRACT FROM AUTHOR]

In the current study, wave analysis in porous thermoelastic plates with microtemperature subject to insulated or isothermal boundaries is the main focus. The governing equations, after expressing for the two‐dimensional case, are converted into nondimensional quantities. For further simplification, potential functions have been used. The normal mode analysis technique is applied to solve the problem. This technique is an influential methodology that furnishes suitable solutions with no presumed limitations. For stress‐free insulated, or isothermal boundaries, the frequency equations for symmetric and skew‐symmetric modes of wave propagation are derived. The attributes of waves (phase velocity, attenuation coefficient, specific loss, and penetration depth) are computed numerically and presented graphically to show the impacts of porosity and microtemperature. Particular cases of porous thermoelastic plates and thermoelastic plates with microtemperatures are presented. The present problem provides a theoretical foundation for the design and development of new composite materials and surface acoustic devices. [ABSTRACT FROM AUTHOR]

A plane contact problem on the interaction of a rigid stamp with a poroelastic strip lying on a Winkler base was investigated. The deformation of the strip was modeled based on the equations of the Cowin–Nunziato poroelastic bodies theory. It was assumed that the base of the stamp has a flat or parabolic shape and there is no friction in the contact zone. With the help of the Fourier integral transformation, the problems stated were reduced to an integral equation for an unknown contact stress, which was solved with the use of the collocation and the asymptotic methods. The values of contact stresses, sizes of the contact area in the case of a parabolic stamp and the relative deformation of the surface outside the stamp were determined. A comparative analysis of the studied quantities for various values of the poroelastic strip parameters and the coefficient of subgrade resistance of the Winkler base was carried out. Numerical results are presented in the form of tables and graphs. [ABSTRACT FROM AUTHOR]

The structure of kukersite organic matter has been a matter of scientific investigation and disputes over a hundred years. When considering the publications on the subject the authors of the current article concluded that the structure of kukersite is well described by a model proposed independently by Ülo Lille and Peter Blokker at the beginning of this millennium. This model characterizes the behaviour of kukersite in thermal processing and predicts the behaviour of oil shale kerogen in oxidation and other chemical transformations. The structural model may serve as a basis for new technologies for oil shale processing in order to get valuable chemicals directly from it. [ABSTRACT FROM AUTHOR]

An innovative concept of a microelongated non-local semiconductor material is developed. According to photothermal transport processes, the material is stimulated. When the thermal conductivity of the non-local medium is changed, the photo-thermoelasticity theories are used. The microelongation instance and the interference between the photothermoelastic propagation waves in the non-local medium are both described by the effective framework. When electronic and thermoelastic deformation processes are taking place, thermal conductivity may be thought of as a linear function of temperature. The dimensionless main fields are extracted using a maps converter in two dimensions (2D). The fundamental equations have been transformed into higher-order ordinary differential equations using the harmonic wave approach in accordance with the normal mode analysis. Applying a few conditions chosen from the non-local semiconductor surface yields complete solutions. With graphics, the numerical simulation results for silicon (Si) are shown. For the considered physical variables during the changing thermal conductivity and microelongation, comparisons are performed and explained. [ABSTRACT FROM AUTHOR]

The governing equations for microelongated semiconductors are presented in a novel mathematical–physical way. The model is examined in line with the photogenerated transport processes when the microelongated elastic non-local semiconductor medium is powered. The primary governing equations reveal the interplay between elastic, thermal, and plasma waves when microelongation is taken into account. In this regard, the generalized photothermoelasticity theory is taken into consideration. The dimensionless analytical formulations for temperature, carrier density, displacement, stresses, and microelongation distributions have been obtained using the harmonic wave technique. During the electronic and thermoelastic deformation processes in two dimensions, the general solutions of the principal distributions are determined (2D). To get the full answers, several criteria are taken into account at the non-local medium's free surface. The numerical results were obtained using computer programming. These data were represented graphically for the work of the simulation and comparison with the experimental results under the influence of some of the variables under study. [ABSTRACT FROM AUTHOR]

Outlined here is an innovative method for characterizing a layer of microelongated semiconductor material under excitation. Fractional time derivatives of a heat equation with a rotational field are used to probe the model during photo-excitation processes. Micropolar-thermoelasticity theory, which the model implements, introduces the microelongation scalar function to characterize the processes occurring inside the microelements. When the microelongation parameters are considered following the photo-thermoelasticity theory, the model investigates the interaction scenario between optical-thermo-mechanical waves under the impact of rotation parameters. During electronic and thermoelastic deformation, the key governing equations have been reduced to dimensionless form. Laplace and Fourier's transformations are used to solve this mathematical problem. Isotropic, homogeneous, and linear microelongated semiconductor medium's general solutions to their respective fundamental fields are derived in two dimensions (2D). To get complete solutions, several measurements must be taken at the free surface of the medium. As an example of numerical modeling of the important fields, we will use the silicon (Si) material's physicomechanical characteristics. Several comparisons were made using different values of relaxation time and rotation parameters, and the results were graphically shown. [ABSTRACT FROM AUTHOR]

According to recent research, the theoretical consequences of viscoelastic materials may be adequately described using fractional calculus. A novel model for the fractional time derivative of the Kelvin-Voigt type of viscoelastic semiconductor material has been provided in this study. The Atangana and Baleanu (AB) fractional derivatives operator is utilized, which employs the generalized Mittag–Leffler function as a nonlocal and non-singular kernel and respects all features of fractional derivatives. The Moore–Gibson–Thompson (MGT) photothermal heat transfer model has also been considered to explain the mechanism of photosensitive heat transfer and the interplay between plasma, elastic, and heat signals. This fractional model is used to explore thermal and photoacoustic interactions when an infinite viscoelastic rotating material with a circular cylindrical hole is exposed to a time-dependent variable heat in the presence of an axial constant magnetic field. The solutions of photothermal field variables are obtained using Laplace transform methods, and the technique of Fourier series expansions is applied to obtain the inversions. Results have been listed to examine how the fractional-order and mechanical viscoelastic relaxation parameters affect different photo-thermoelastic variables that have physical meaning. [ABSTRACT FROM AUTHOR]

We derive analytical solutions for the uniaxial extension problem for the relaxed micromorphic continuum and other generalized continua. These solutions may help in the identification of material parameters of generalized continua which are able to disclose size effects. [ABSTRACT FROM AUTHOR]

The main goal of this research is to provide a novel model that describes an optically heated layer of an excited non-local microelongated semiconductor material. In a rotating field, the model is examined as the photo-excitation processes occur. The model presents the microelongation scalar function, which describes the microelement processes according to the micropolar-thermoelasticity theory. The model analyses the interaction situation between optical-thermomechanical waves under the impact of rotation parameters when the microelongation parameters are taken into consideration according to the photo-thermoelasticity theory. During the electronic and thermoelastic deformation, the fundamental governing equations were obtained in dimensionless form, and they were investigated using the harmonic wave methodology. Two-dimensional general solutions for the fundamental fields of an isotropic, homogeneous, and linear non-local microelongated semiconductor medium are derived (2D). The free surface of the medium is subjected to several conditions to produce complete solutions due to the laser pulse. The physical properties of silicon (Si) material are used to show numerical modeling of the main fields. Some comparisons are made and graphically shown under the impact of various relaxation time and rotational parameters. [ABSTRACT FROM AUTHOR]

This work focuses on presenting a novel model describing a layer of an excited microelongated semiconductor material. During the photo-excitation processes, the model is investigated in a rotational field. The model introduced the microelongation scalar function, which describes the microelement processes according to the micropolar-thermoelasticity theory. The model studies the interaction case between optical-thermo-mechanical waves under the effect of rotation parameters when the microelongation parameters are taken into consideration according to the photo-thermoelasticity theory. The main governing equations have been taken in a dimensionless form during the electronic and thermoelastic deformation and they have been studied under the harmonic wave technique. The general solutions of the basic fields of isotropic, homogeneous, and linear microelongated semiconductor medium are obtained in two dimensions (2D). Many conditions are taken at the free surface of the medium to obtain the complete solutions. The physical parameters of silicon (Si) are used to illustrate the numerical simulation of the main fields. Several comparisons were performed and illustrated graphically under the influence of different parameters of relaxation time and rotation. [ABSTRACT FROM AUTHOR]

A theoretical novel model is investigated that describes the dynamic effects of the microelongation processes of an exciting semiconductor medium. The influence of the magnetic field for the optically excited medium is taken into consideration according to the photothermal transport characteristics. The governing equations were derived during the electronic (ED) and thermoelastic (TED) deformation processes when the microelongation parameters of the semiconductor medium were taken into account. The interference between thermal-magnetic-microelongat-plasma-mechanical waves is investigated. The dimensionless expressions are utilized to solve the main equations according to the harmonic wave technique in two-dimensional (2D) deformation. The complete solutions of the expressions of the physical field were obtained when some conditions were taken on the outer semiconductor surface. The theoretical microelongated semiconductor model in this investigation was checked by comparing it with some previous studies. The numerical simulation for the main physical field distributions is graphically displayed when the silicon (Si) material is used. The impact of various factors such as the magnetic field, thermal memory effect, and microelongation on the wave propagations for main fields was discussed. [ABSTRACT FROM AUTHOR]

The heating of solids occurs due to the absorbed light from the heat source. Photothermal spectroscopy is a method of measuring the optical absorption and thermal properties of semiconductor materials using high‐sensitivity spectroscopic techniques. In the present paper, the harmonic solution as an analytical solution is provided to describe the semiconductor photothermal microelongated medium with microtemperatures in the gravity field. The proposed photothermal microelongated model is subjected to an induced magnetic field to observe the Thomson effect. The numerical calculations for the components of thermal stresses, displacement, temperature field, and carrier density are obtained using the harmonic solution approach. The propagation of heat, elastic, and plasma waves, as well as the distributions of each investigated field, were examined and explained. The comparison is also used to see how the gravity, Thomson effect, and the photo‐excitation have more observable effects on the distribution of the medium fields during their values changes. With the development of technologies, the semiconducting materials were used widely in modern engineering. The study of wave propagation in a semiconducting medium will have important academic significance and application value. [ABSTRACT FROM AUTHOR]

A theoretical analysis of the dynamic impacts of a novel model in the microelongated-stimulated semiconductor medium is investigated. The influence of the magnetic field of the optically excited medium is taken into consideration according to the photothermal transport processes. The governing equations were created during the electronic (ED) and thermoelastic (TED) deformation processes. Thermal conductivity of the semiconductor microelongation medium is taken as temperature dependent. The interaction of thermal, microelongate, plasma, and mechanical waves is examined. Dimensionless formulae are used to solve the main equations in two dimensions (2D) using the harmonic wave method. The physical field equations have complete solutions when some conditions are applied to the semiconductor surface. The theoretical microelongated semiconductor model employed in this experiment was confirmed by comparing it to certain earlier studies. The numerical simulation for the principal physical field distributions is graphically displayed when silicon (Si) material is employed. The topic of the discussion was the impact of several factors, such as the magnetic field, thermal memory, and microelongation, on the propagation of waves for major fields. [ABSTRACT FROM AUTHOR]

We consider the classical Mindlin–Eringen linear micromorphic model with a new strictly weaker set of displacement boundary conditions. The new consistent coupling condition aims at minimizing spurious influences from arbitrary boundary prescription for the additional microdistortion field P . In effect, P is now only required to match the tangential derivative of the classical displacement u which is known at the Dirichlet part of the boundary. We derive the full boundary condition, in adding the missing Neumann condition on the Dirichlet part. We show existence and uniqueness of the static problem for this weaker boundary condition. These results are based on new coercive inequalities for incompatible tensor fields with prescribed tangential part. Finally, we show that compared to classical Dirichlet conditions on u and P , the new boundary condition modifies the interpretation of the constitutive parameters. [ABSTRACT FROM AUTHOR]

In the presented work, the propagation of thermal-plasma-mechanical waves of an elastic microelongated semiconductor medium is studied. A novel model describes the interference between waves under the influence of a rotational field when the medium's thermal conductivity is variable. Thermal conductivity is selected based on the temperature when the microelongated semiconductor medium is in an excited state. The microelongation parameters of the medium are taken into account according to the microelement transport processes for the micropolar-photo-thermoelasticity theory. The governing equations are investigated in two dimensions (2D) when the main quantities are taken dimensionless. To add, harmonic wave analysis is employed to obtain complete analytical solutions of the main physical fields when some boundary conditions are chosen at the medium surface. The influence of physical fields variables is analyzed and illustrated graphically for silicon (Si) material in different values of variable thermal conductivity, thermal relaxation times and rotation parameters. [ABSTRACT FROM AUTHOR]

This research focuses on boosting seawater pretreatment and desalination through electrocoagulation (EC)/ultrafiltration (UF) and electrocoagulation (EC)/nanofiltration (NF) processes. We first optimized the key parameters of the EC process using aluminum (Al) and iron (Fe) electrodes. Experimental results show EC process is efficient under optimal conditions. Second, membrane filtration using UF (ES10B), NF(UTC60) and NF(200) as post-processing steps to the EC process were experimented with. EC(Al)/NF(UTC60) combination resulted in the highest removal rate of organic matter (COD 98%, TOC 95%, fluorescence [humic and fulvic acids] 68%), optical density (OD 600nm 75%, turbidity 70%, conductivity 64%). In terms of major ions removal, up to 55% was achieved as NF decreases conductivity, salinity, and hardness. EC(Al)/NF(UTC60) seawater permeate demonstrated the best results in terms of lowest flux decline (J/J o  = 0.9) and fouling, which was realized by resistance in series and recovery factor rate (%). Additionally, NF(UTC60) fouling reversibility led to a longer lifetime and higher recovery factor (93%). PRACTITIONER POINTS: Pretreatment by hybrid processes was experimented with to enhance the saline water treatment. Organic matter (COD 98%, TOC 95%, fluorescence [humic and fulvic acids] 68%) and turbidity were successfully removed. Salinity and hardness (conductivity 64%) were highly reduced by NF. Flux decline, retention rate, and membrane fouling were studied., (© 2024 Water Environment Federation.)

The replacement of missing teeth over the long term is a major challenge in implantology to regain chewing function and aesthetics. However, following the surgical procedure, some problems such as a fracture of the bone, a lack of osseointegration or the occurrence of peri-implantitis affect the balance of the implant-bone system. Studies focus on optimizing the shape, material or surface topography. However, they consider that bone behavior like conventional elastic material. To consider its microstructure, the use of the micropolar elasticity to describe this living material is a judicious choice. The analysis of the internal stresses in response to an external stimuli on the implant-bone micropolar system will allow to optimize the size, the shape and the material of the implant by taking into account the contribution of the bone microstructure on its global behavior. [ABSTRACT FROM AUTHOR]

In this work, the method of initial functions for a micropolar medium under conditions of plane strain has been developed. In a Cartesian rectangular coordinate system, the solution of the differential equilibrium equations in displacements of the micropolar isotropic theory of elasticity in the form of a linear combination of the stress–strain state (SSS) components defined on the line x = 0 (initial functions) with coefficients in operator form is constructed. The choice of initial functions in the form of trigonometric series makes it possible to solve the boundary problem of deformation of a micropolar rectangle ( h × l ) with arbitrary boundary conditions on the sides x = 0 , h and the type of free support on the sides y = 0 , l . The obtained solution was used to study the SSS of a rectangle made of human bone considered as an isotropic micropolar material. The results of the SSS study, depending on the size of the rectangle, are presented. The limiting dimensions at which the SSS values of the components differ by 5% from the values of the corresponding components calculated according to the classical theory of elasticity are determined. [ABSTRACT FROM AUTHOR]

This study is concerned with the theory of Cosserat thermoelastic media, whose micro-particles possess microtemperatures. The mixed initial boundary value problem considered in this context is transformed in a temporally evolutionary equation on a Hilbert space. Using some results from the theory of semigroups, the existence and uniqueness of solution is proved. In the same manner, it approached the continuous dependence of the solution upon initial data and loads. From what we have studied, neither on the internet nor in the databases, we have not found qualitative issues addressed regarding the mixed problem in the context of the theory of thermoelasticity of Cosserat environments, in which the contribution of inner structure and microtemperatures are taken into account. [ABSTRACT FROM AUTHOR]

We solve the St. Venant torsion problem for an infinite cylindrical rod whose behaviour is described by a family of isotropic generalized continua, including the relaxed micromorphic and classical micromorphic model. The results can be used to determine the material parameters of these models. Special attention is given to the possible nonphysical stiffness singularity for a vanishing rod diameter, because slender specimens are, in general, described as stiffer. [ABSTRACT FROM AUTHOR]

This paper focuses on the analysis of two‐dimensional steady‐state thermal stresses based on micropolar theory in hollow and solid cylinders which are made of functionally graded materials (FGM) under asymmetric loading condition (r, θ) with the general thermal and mechanical boundary conditions along the inside and outside surfaces. The heat conduction and Navier equations were solved using the separation of variables and complex Fourier series for micropolar theory. Finally, the exact numerical results for both micropolar and classical solutions are illustrated and discussed using two examples: In Example 1, based on the micropolar theory, when thermal tensions are exerted on the inside surface of the cylinder, some of the strain energy is used for the object rotation; therefore, considering this condition, the calculated values resulted from the micropolar theory are smaller than those of the classic theory. In Example 2, by exerting normal tension on the inside surface of the cylinder, the rotation created is very small; therefore, the results of the micropolar and classic theories are similar. In addition to FGM materials, this solution is applicable to minerals and organic matter multiphase fiber and particulate composites, soil, rock, concrete, and various granular materials [59]. [ABSTRACT FROM AUTHOR]

In our present study, we approach a linear theory for the thermoelasticity of type III for Cosserat media. At the beginning we introduce the equations and conditions, specific for a mixed problem in this context, namely the motion and energy equations, the initial condition and boundary relations. After that, we establish two results regarding the solution unique to the problem and two results on the continuous dependence of solutions, for the same mixed problem. Both problems that we address in our paper (uniqueness and continuous dependence) are not based on the material symmetries of the medium. Moreover, our results concern the theory of type III thermoelasticity for Cosserat media in their most general form, namely anisotropic. [ABSTRACT FROM AUTHOR]

In this work we study, from the numerical point of view, a one-dimensional thermoelastic problem where the thermal law is of type III. Quasi-static microvoids are also assumed within the model. The variational formulation leads to a coupled linear system made of variational equations and it is written in terms of the velocity, the volume fraction and the temperature. Fully discrete approximations are introduced by using the finite element method and the backward Euler method. A discrete stability property and a priori error estimates are proved, deriving the linear convergence under adequate additional regularity. Finally, some numerical simulations are presented to demonstrate the accuracy of the approximation and the behavior of the solution. [ABSTRACT FROM AUTHOR]

This paper is concerned with the deformation of beams in the framework of the linear theory of micromorphic elastic solids. First, the plane strain of anisotropic and homogeneous elastic cylinders is investigated. Existence and uniqueness results are presented. Then, Saint-Venant's problem for micromorphic beams is formulated. A method is established to reduce the extension, bending and torsion to the study of some plane problems. Finally, the deformation of beams loaded on the lateral surface is investigated. As a special case, the solution of the flexure problem is obtained. The method is used to study the deformation of a micromorphic rod subjected to a uniform pressure on the lateral surface. [ABSTRACT FROM AUTHOR]

We consider a class of semilinear problems for binary mixtures in the presence of viscoelastic dissipation. This paper aims to study the existence and properties of long-time dynamics in a two-dimensional setting. More precisely, we first prove the existence of a finite-dimensional global attractor that exhibits additional regularity in higher topology. Secondly, we show that the dynamical system has a generalized fractal exponential attractor. [ABSTRACT FROM AUTHOR]

We consider a thermoelastic theory in which the equations that govern the evolution are linear with respect to the thermal displacement and nonlinear with regards to gradients of displacements and temperature. Our results refer to the non-existence of solutions for some mixed problems, considered in this context. We also address the instability of solutions of the considered problems. We will treat separately the case where the mechanical effects are neglected, taking into account only the thermal effect. In this case our problem has a nonlinear structure. [ABSTRACT FROM AUTHOR]

This paper is devoted to studying the linear system of partial differential equations modelling a one-dimensional thermo-porous-elastic problem with microtemperatures in the context of the dual-phase-lag heat conduction. Existence, uniqueness, and exponential decay of solutions are proved. Polynomial stability is also obtained in the case that the relaxation parameters satisfy a certain equality. Our arguments are based on the theory of semigroups of linear operators. [ABSTRACT FROM AUTHOR]

We consider the cylindrical bending problem for an infinite plate as modeled with a family of generalized continuum models, including the micromorphic approach. The models allow to describe length scale effects in the sense that thinner specimens are comparatively stiffer. We provide the analytical solution for each case and exhibits the predicted bending stiffness. The relaxed micromorphic continuum shows bounded bending stiffness for arbitrary thin specimens, while classical micromorphic continuum or gradient elasticity as well as Cosserat models (Neff et al. in Acta Mechanica 211(3–4):237–249, 2010) exhibit unphysical unbounded bending stiffness for arbitrary thin specimens. This finding highlights the advantage of using the relaxed micromorphic model, which has a definite limit stiffness for small samples and which aids in identifying the relevant material parameters. [ABSTRACT FROM AUTHOR]

We study the behavior in time of the solutions to several systems of equations for porous-thermo-elastic problems when one of the variables is considered to be quasi-static or, in other words, whose second time derivative can be neglected. We analyze three different situations using the classical Fourier law and also the type II or type III Green–Naghdi heat conduction models. [ABSTRACT FROM AUTHOR]

Producing valuable transportation fuels from shale oil has long been a goal among the industries concerned, but to meet modern environmental regulations a significant upgrading is required involving removing heteroatoms from it. The quantity of sulfur, nitrogen and oxygen in shale oil is one of the major obstacles to its wider use. Unlike petroleum whose upgrading consists mainly in desulfurization, for shale oils denitrification and deoxygenation are also important. This review compiles and summarizes the extensive research that has been performed on removing sulfur, nitrogen and oxygen from shale oil. By far the most widely investigated method has been hydrotreatment, but the results of work done with other methods are also presented. [ABSTRACT FROM AUTHOR]

The work presented is devoted to the axisymmetric contact problems on the interaction of a rigid stamp and an elastic layer fixed on a porous elastic half-space by using the Cowin–Nunziato model. It is assumed that the stamp basis has a flat or parabolic shape and friction is absent in the contact zone. With the help of the Hankel integral transform, the problems stated are reduced to solving integral equations for the unknown contact stress by using the collocation method. The values of contact stresses and the contact area in the case of a parabolic stamp are found. The normal stresses on the interface between the elastic layer and the poroelastic half-space are investigated. The relationship between the force acting on the stamp and the corresponding displacement, which is one of the main characteristics in determining the mechanical parameters of the material by the indentation method, is investigated. A comparative analysis of the values found for various parameters of the elastic layer and the poroelastic base is carried out. The numerical results are presented in a table and in the form of graphs. [ABSTRACT FROM AUTHOR]

A novel model in the photo-thermoelasticity theory with microstretch properties is studied. The plasma-elastic-thermal plane waves are propagated in a linear isotropic generalized photo-thermo-microstretch elastic semiconductor solid medium. The photothermal excitation occurs in the context of the microinertia of the microelement process during two-dimensional (2D) deformation. The harmonic wave techniques are used to get the solutions for the basic variables. The analytical solution of the main physical fields; carrier intensity, normal displacement components, temperature, stress load force, microstress and tangential coupled stress can be obtained. Some graphics illustrated when using the plasma, thermal and mechanical load boundary conditions are applied at the outer free surface of the elastic medium. Some semiconductor materials, as silicon (Si) and Germanium (Ge), are used to make the numerical simulation and some comparisons in different thermal memories are made. The main physical variables with new parameters are discussed theoretically and shown graphically. [ABSTRACT FROM AUTHOR]

In the present paper, we consider an elastic circle and a plane with circular hole with voids and microtemperatures. Representations of a general solution of a system of equations for a homogeneous isotropic thermoelastic medium with voids and microtemperatures are constructed by means of the elementary (harmonic, bi‐harmonic and meta‐harmonic) functions. The Dirichlet type boundary value problems for a circle and for a plane with circular hole are solved explicitly. The obtained solutions are represented in the form of absolutely and uniformly convergent series. [ABSTRACT FROM AUTHOR]

The theory of generalized thermoelasticity with two temperatures is employed to study the problem of two-dimensional disturbances in thermo-microstretch elastic solid under the effect of the magnetic field and rotation. The formulation of the problem applied in the context of three-phase-lag model, Green–Naghdi theory with energy dissipation and coupled theory. The general solutions for field quantities are obtained using the method of normal mode analysis. Both numerical and graphical results are discussed quantitatively with respect to various parameters embedded in the system. The results indicate that the effect of rotation, magnetic field, two-temperature parameter, Coriolis acceleration and vertical displacement is very pronounced. The results of earlier workers have been reduced as particular cases from the present study. [ABSTRACT FROM AUTHOR]

In the present paper, the linear theory of viscoelasticity for binary porous mixtures is considered. The fundamental solution of the system of steady vibration equations is constructed, and its basic properties are established. Green's identities of this theory are obtained. The uniqueness theorems for classical solutions of the internal and external basic boundary value problems (BVPs) of steady vibrations are proved. The surface and volume potentials are introduced, and their basic properties are established. The determinants of symbolic matrices of the singular integral operators are calculated explicitly, and the BVPs are reduced to the always solvable singular integral equations for which Fredholm's theorems are valid. Finally, the existence theorems for classical solutions of the internal and external BVPs of steady vibrations are proved by means of the potential method and the theory of singular integral equations. [ABSTRACT FROM AUTHOR]

In this paper, we consider the linear theory of binary mixtures for thermoviscoelastic diffusion materials derived by Aouadi et al. (J Therm Stress 41:1414–1431, 2018). We establish the necessary and sufficient conditions to get a dissipation inequality for isotropic centrosymmetric materials. With the help of the semigroup theory of linear operators, we prove the well posedness of the higher-dimensional problem. Then, we show that the associated C 0 -semigroup is analytic. Exponential stability and impossibility of localization of the solutions in time are immediate consequences. [ABSTRACT FROM AUTHOR]

This article is concerned with the linear theory of elastic materials with voids. With respect to the classical theory of elasticity, this model is characterized by four independent kinematic variables: the displacement field u i (i = 1 , 2 , 3) and the change in volume fraction ψ. First, we present the field equations in the equilibrium theory and derive the equations of the plane strain problem. Then, the problem of a cylindrical rigid inclusion in an infinite body is investigated. The results are obtained in closed form. The solution can be considered as a generalization of the corresponding problem in the classical theory of elasticity. The displacement field and the stresses are expressed by mean of explicit formulas. The maximum tensile stress and the stress concentration factor are calculated. [ABSTRACT FROM AUTHOR]

The semi-inverse analytical solution of a pure bending problem for a piezoelectric layer is developed in the framework of linear electroelasticity theory with strain gradient and electric field gradient effects. The simplified gradient theory of transversely isotropic material with a single additional length scale parameter is considered. A two-dimensional solution is derived assuming plane strain state of a layer (cylindrical bending of a plate) and low dielectric properties of the surrounding medium. The electromechanical response of a layer is found under conditions of prescribed bending moments at the end faces. Boundary conditions on the top and bottom surfaces of a layer are satisfied exactly. The analytical solution is validated based on numerical finite element modeling. It is shown that the obtained solutions can be used for the validation of size-dependent beam and plate models in the second gradient electroelasticity theory. [ABSTRACT FROM AUTHOR]

We study the existence of solutions arising from the modelling of elastic materials using generalized theories of continua. In view of some evidence from physics of metamaterials, we focus our effort on two recent nonstandard relaxed micromorphic models including novel micro-inertia terms. These novel micro-inertia terms are needed to better capture the band-gap response. The existence proof is based on the Banach fixed-point theorem. [ABSTRACT FROM AUTHOR]

This paper is concerned with the linear theory of microstretch elastic solids. We study the deformation of a chiral cylinder subjected to body loads, to traction on the lateral surface and to resultant forces and moments on the ends. The body loads and the surface loading are assumed to be independent of the axial coordinate. The solution is reduced to solving some plane problems. The results are used to study the deformation of a circular cylinder subjected to a uniform pressure acting on the lateral surface. [ABSTRACT FROM AUTHOR]

This paper gives a historic overview of the innovation activities in the former Soviet Union, including the Estonian SSR, in the direct chemical processing of organic matter concentrates of Estonian oil shale kukersite (kukersite) as well as other sapropelites. The overview sheds light on the laboratory experiments started in the 1950s and subsequent extensive, tripleshift work on a pilot scale on nitric acid, to produce individual dicarboxylic acids from succinic to sebacic acids, their dimethyl esters or mixtures in the 1980s. [ABSTRACT FROM AUTHOR]