On the minimum principle for dipolar materials with stretch

In the present paper we generalize the results obtained by Iesan and Quintanilla for microstretch elastic bodies in order to cover dipolar elastic materials with stretch. For the boundary value problem considered in this context, we prove a generalized existence result and, also, an extension of the principle of minimum potential energy.     

Analysis on plane waves through magneto-thermoelastic microstretch rotating medium with temperature dependent elastic properties

The article is concerned with the deformation of an infinite microstretch generalized thermoelastic medium rotating with some angular frequency. Initially the medium is stressed with some hydrostatic forces and is also considered under the effects of initially applied magnetic and gravitational field. The theory proposed by Green–Naghdi is selected to analyze the heat wave conduction through the medium. An analytical technique of the Eigen value expansion method is adopted to get the analytic solution for waves propagating through the medium. The theoretical results obtained are further converted to graphical for a particular medium. Graphically, we presented the influence of each mechanical force on the amplitude of waves propagating through elastic media. The comparison is also made between the theories used.     

A partition of energy in thermoelasticity of microstretch bodies

This paper is concerned with microstretch thermoelastic materials. For the mixed initial boundary value problem defined in this context, we prove that the Cesaro means of the kinetic and strain energies of a solution with finite energy become asymptotic equal as time tends to infinity.     

Lagrange identity method for microstretch thermoelastic materials

Our paper is concerned with some basic theorems for microstretch thermoelastic materials. By using the Lagrange identity, we prove the uniqueness theorem and some continuous dependence theorems without recourse to any energy conservation law, or to any boundedness assumptions on the thermoelastic coefficients. Moreover, we avoid the use of positive definiteness assumptions on the thermoelastic coefficients.     

Propagation of plane waves in microstretch fluid

The propagation of plane harmonic waves are studied in a microstretch fluid medium. It is found that five basic waves can propagate at distinct speeds in an infinite linear homogeneous isotropic microstretch fluid. Out of these five waves, one is a longitudinal micro-rotational wave, two are coupled longitudinal waves and remaining two are coupled transverse waves. The longitudinal micro-rotational wave travels independently and is not influenced by the microstretching of the medium, while the coupled longitudinal waves arise due to the presence of microstretching and coupled transverse waves arise due to the presence of micro-rotation in the medium. Speed of propagation of all the waves are found to be complex valued and dispersive at low frequency, but almost non-dispersive at high frequency. Due to complex valued speeds of propagation, all the waves are attenuating but differently. Coupled sets of longitudinal waves reduce to a longitudinal wave of micropolar fluid in the absence of microstretching. Reflection phenomena of a set of coupled longitudinal waves incident obliquely at the free surface of a microstretch fluid half-space has been investigated. Closed formulae for the reflection coefficients are presented and computed numerically for a particular medium. The real and imaginary parts of the complex speeds of all the waves and their corresponding attenuation coefficients have also been studied numerically and depicted graphically against frequency parameter.     

Micromorphic continuum model for electromagnetoelastic solids

The microcontinuum theory of electroelasticity is considered for polarizable dielectrics on the basis of dipole and quadrupole densities as microfields. Electromagnetic contributions to force, couple, and power are derived, and their correspondence with quantities evaluated in terms of macroscopic polarization and magnetization is examined. A constitutive model that accounts for dissipation is proposed via internal variables satisfying suitable evolution equations. This approach reveals different roles of polarization and strain measures in dissipative processes. The link between the spin inertia tensor and the pair of dipole and quadrupole per unit mass is exploited to derive a nonlinear system of governing equations for a reduced set of variables. The special cases of microstretch and micropolar continua are discussed.     

磁场对液体-微伸缩固体介面波传播的影响

在一个传播理想的非粘性液体半空间,和一个传播理想的微伸缩弹性固体半空间之间,研究介面处纵波的反射和透射.在两个半空间中,满足介面处必需的边界条件下,得到控制方程的适当解,是一组以不同反射和透射波振幅比表示的5个非齐次方程.以水和铝-环氧树脂合成材料介面为实际例子,用Gauss消除法的Fortran程序求解方程组.考虑存在和不存在外加横向磁场两种情况,在某些入射角范围内,计算振幅比的数值解.最后用图形给出横向磁场对不同反射和透射波振幅比的影响.     

Mean field modeling of isotropic random Cauchy elasticity versus microstretch elasticity

We show that the averaged response of random isotropic Cauchy elastic material can be described analytically. It leads to a higher gradient model with explicit expressions for the dependence on the second derivatives of the mean field. A subsequent penalty formulation coincides with a linear elastic micro-stretch model with specific choice of constitutive parameters, depending only on the average cut-off length (the internal characteristic length scale L_c > 0). Thus the microstretch displacement field can be interpreted as an approximated mean field response for these parameter ranges. The mean field free energy in this micro-stretch formulation is not uniformly pointwise positive, nevertheless, the model is well posed.      

Deflection analysis of micro-scale microstretch thermoelastic beam resonators under harmonic loading

In this paper, the flexural vibrations of homogeneous, isotropic, generalized micropolar microstretch thermoelastic thin Euler–Bernoulli beam resonators, due to time harmonic load have been investigated. The axial ends of the beam are assumed to be at either clamped-clamped, simply supported-simply supported or clamped-free conditions. The governing equations have been solved analytically by using Laplace transforms technique twice with respect to time and space variables respectively. The inversion of Laplace transform in time domain has been performed by using the calculus of residues to obtain deflection. The numerical simulation has been carried out with the help of MATLAB software for magnesium like material. The graphical representations and observations have been discussed for deflection of beam under various boundary conditions and for distinct considered values of time and space as well.     

Feynman operator calculus: The constructive theory

In this paper, we survey progress on the Feynman operator calculus and path integral. We first develop an operator version of the Henstock-Kurzweil integral, construct the operator calculus and extend the Hille-Yosida theory. This shows that our approach is a natural extension of operator theory to the time-ordered setting. As an application, we unify the theory of time-dependent parabolic and hyperbolic evolution equations. Our theory is then reformulated as a sum over paths, providing a completely rigorous foundation for the Feynman path integral. Using our disentanglement approach, we extend the Trotter-Kato theory.     

Effectiveness in RPL, with applications to continuous logic

In this paper, we introduce a foundation for computable model theory of rational Pavelka logic (an extension of ?ukasiewicz logic) and continuous logic, and prove effective versions of some related theorems in model theory. We show how to reduce continuous logic to rational Pavelka logic. We also define notions of computability and decidability of a model for logics with computable, but uncountable, set of truth values; we show that provability degree of a formula with respect to a linear theory is computable, and use this to carry out an effective Henkin construction. Therefore, for any effectively given consistent linear theory in continuous logic, we effectively produce its decidable model. This is the best possible, since we show that the computable model theory of continuous logic is an extension of computable model theory of classical logic. We conclude with noting that the unique separable model of a separably categorical and computably axiomatizable theory (such as that of a probability space or an L^p Banach lattice) is decidable.     

MULTIPLICITY OF SOLUTIONS TO ASYMPTOTICALLY LINEAR SECOND-ORDER ORDINARY DIFFERENTIAL SYSTEM

In this paper,we consider an asymptotically linear second-order ordinary differential system with Dirchlet boundary value conditions. Under some conditions,we show the multiplicity of solutions to the system by the Morse theory and an index theory.     

Function spaces in metrically generated theories

The theory of metrically generated constructs provides us with an excellent setting for the study of function spaces. In this paper we develop a function space theory for metrically generated constructs and, by considering different metrically generated constructs, we capture interesting examples. For instance, for uniform spaces we retrieve the uniformity of uniform convergence and its generalization to Σ-convergence and for UG-spaces we obtain a quantified version of these structures. Our theory also allows for many applications, in particular we are able to characterize the complete subspaces of these function spaces and we succeed in producing an appropriate Ascoli theorem.     

Hylomorphic solitons and charged Q-balls: Existence and stability

In this paper we present a general theoretical framework from which several known results (a some new ones) on the existence and stability of solitons can be recovered.We give an abstract definition of solitary wave and soliton and we develope an abstract existence theory. This theory provides a powerful tool to study the existence of solitons for the Klein–Gordon equations as well as for gauge theories. Applying this theory, we prove the existence of a continuous family of stable charged Q-balls.     

Density of an (r,R)-system

In this paper we give a complete geometrical theory for the study of the exact lower bound of the density of n-dimensional lattices. For arbitrary (r, R)-systems we prove an analog of well known theorems due to Rogers from the theory of packings, and also from this same theory, an analog of a theorem due to Coxeter, Few, and Rogers. Several special examples are treated.     

Bivariant cyclic theory

In this paper we construct a bivariant version of cyclic cohomology and study its fundamental properties. We prove universal coefficient theorems relating the bivariant theory with cyclic homology and cohomology, we construct products in the bivariant theory, and we analyse the notion of an HC-equivalence.Dedicated to Alexander Grothendieck     

The ∞‐Besov capacity problem

A theory of ∞‐Besov capacities is developed and several applications are provided. In particular, we solve an open problem in the theory of limits of the ∞‐Besov semi‐norms, we obtain new restriction‐extension inequalities, and we characterize the pointwise multipliers acting on the ∞‐Besov spaces.     

两相同部件冷贮备可修系统算子性质

研究了两相同部件冷贮备可修系统算子性质,此系统由2个同型部件及一个修理设备构成.其中一个部件工作,另一个部件冷储备.运用C_0半群的理论,证明了系统算子是稠定的预解正算子,得出了系统算子的共轭算子及其定义域,并证明了系统算子的增长界为0.最后运用了预解正算子中共尾的概念及相关理论,证明了系统算子的谱上界也是0.     

两同型部件温贮备可修系统算子性质

研究了两同型部件温贮备可修系统,此系统由2个同型部件及一个修理设备构成.其中一个部件工作,另一个部件温储备.运用C_o半群的理论,证明系统算子是稠定的预解正算子,得出系统算子的共轭算子及其定义域,并证明了系统算子的增长界为O.最后运用了预解正算子中共尾的概念及相关理论,证明系统算子的谱上界也是0.     

Stable étale realization and étale cobordism

We show that there is a stable homotopy theory of profinite spaces and use it for two main applications. On the one hand we construct an étale topological realization of the stable A¹-homotopy theory of smooth schemes over a base field of arbitrary characteristic in analogy to the complex realization functor for fields of characteristic zero.On the other hand we get a natural setting for étale cohomology theories. In particular, we define and discuss an étale topological cobordism theory for schemes. It is equipped with an Atiyah-Hirzebruch spectral sequence starting from étale cohomology. Finally, we construct maps from algebraic to étale cobordism and discuss algebraic cobordism with finite coefficients over an algebraically closed field after inverting a Bott element.