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The phase-space kinetic theory for polymeric liquid mixtures is used to obtain an expression for the polymer contribution to the thermal conductivity of a nonflowing, dilute solution of polymers, where the polymer molecules are modeled as Fraenkel dumbbells. This theory takes into account three mechanisms for the energy transport: diffusion of kinetic energy (including the Öttinger-Petrillo term), diffusion of intramolecular energy, and the work done against the intramolecular forces. This paper is an extension of previous developments for the Hookean dumbbell model and the finitely-extensible dumbbell model. A comparison among the dumbbell results suggests that the thermal conductivity increases with chain stiffness. In addition, the zero-shear-rate viscosity and first normal-stress coefficient are also given for the Fraenkel dumbbell model.Dedicated to Prof. John D. Ferry on the occasion of his 85th birthday. 相似文献
4.
Christophe Hazard 《Comptes Rendus Mecanique》2002,330(1):57-68
This paper sums up some recent studies related to the numerical solution of boundary value problems deriving from Maxwell's equations. These studies bring to light the theoretical origins of the ‘corner paradox’ pointed out by numerical experiments for years: In a domain surrounded by a perfect conductor, a ‘nodal’ discretization can approximate the electromagnetic field only if the domain has no reentrant corners or edges. The explanation lies in a mathematical curiosity: two different interpretations of the same variational equation, which are both well-posed and lead either to the physical or a spurious solution! Two strategies which were recently proposed to remedy this flaw of nodal elements are described. To cite this article: C. Hazard, C. R. Mecanique 330 (2002) 57–68 相似文献
5.
D. Iesan 《Journal of Elasticity》1996,42(2):145-163
This paper is concerned with boundary-value problems of the linear theory for binary mixtures of elastic bodies. First, a counterpart of the Boussinesq-Somigliana-Galerkin solution in classical elastostatics is established and the fundamental solutions in the equilibrium theory of homogeneous and isotropic mixtures are derived. Then, representations of Somigliana type for the displacement fields are presented. The potentials of single layer and double layer are used to reduce the boundary-value problems to singular integral equations. Existence and uniqueness results are established. 相似文献
6.
Harley Cohen 《Meccanica》1996,31(5):527-546
A number of simple solutions are obtained which are universal for an homogeneous monotropic elastic rod whose theory is based on a Cosserat-type model.
Sommario Si ottengono alcune soluzioni semplici che sono universali per una trave omogenea monotropica la cui teoria è basata su un modello alla Cosserat.相似文献
7.
A similarity analysis of a nonlinear wave equation in elasticity is studied; in particular, one with anharmonic corrections.
The symmetry transformation give rise to exact solutions via the method of invariants. In some cases, graphical figure of
the solutions are presented. Furthermore, we consider some cases wherein the velocities of the longitudinal and transversal
plane waves are variable. Finally, a brief discussion on how a symmetry analysis on a perturbation of the elasticity equation
can be pursued. 相似文献
8.
In this paper, we rigorously prove that unpredictable oscillations take place in the dynamics of Hopfield-type neural networks (HNNs) when synaptic connections, rates and external inputs are modulo periodic unpredictable. The synaptic connections, rates and inputs are synchronized to obtain the convergence of outputs on the compact subsets of the real axis. The existence, uniqueness, and exponential stability of such motions are discussed. The method of included intervals and the contraction mapping principle are applied to attain the theoretical results. In addition to the analysis, we have provided strong simulation arguments, considering that all the assumed conditions are satisfied. It is shown how a new parameter, degree of periodicity, affects the dynamics of the neural network. 相似文献
9.
Angelica Sharapova Marina Olkhovich Svetlana Blokhina German L. Perlovich 《Molecules (Basel, Switzerland)》2022,27(19)
The important physicochemical properties of three novel bioactive hybrid compounds with different groups (-CH3, -F and -Cl) were studied, including kinetic and thermodynamic solubility in pharmaceutically relevant solvents (buffer solutions and 1-octanol) as well as partition coefficient in system 1-octanol/buffer pH 7.4. The aqueous solubility of these chemicals is poor and ranged from 0.67 × 10−4 to 1.98 × 10−3 mol·L−1. The compounds studied are more soluble in the buffer pH 2.0, simulating the gastrointestinal tract environment (by an order of magnitude) than in the buffer pH 7.4 modelling plasma of blood. The solubility in 1-octanol is significantly higher; that is because of the specific interactions of the compounds with the solvent. The prediction solubility behaviour of the hybrid compounds using Hansen’s three-parameter approach showed acceptable results. The experimental solubility of potential drugs was successfully correlated by means of two commonly known equations: modified Apelblat and van’t Hoff. The temperature dependencies of partition coefficients of new hybrids in the model system 1-octanol/buffer pH 7.4 as a surrogate lipophilicity were measured by the shake flask method. It was found that compounds demonstrated a lipophilic nature and have optimal values of partition coefficients for oral absorption. Bioactive assay manifested that prepared compounds showed antifungal activities equal to or greater than fluconazole. In addition, the thermodynamic aspects of dissolution and partition processes have been examined. Bioactive assay manifested that prepared compounds showed antifungal activities equal to or greater than the reference drug. 相似文献
10.
The content of thisreview consists of recent developments covering an advancedtreatment of multiple crack problems in plane elasticity. Severalelementary solutions are highlighted, which are the fundamentalsfor the formulation of the integral equations. The elementarysolutions include those initiated by point sources or by adistributed traction along the crack face. Two kinds of singularintegral equations, three kinds of Fredholm integral equations,and one kind of hypersingular integral equation are suggested forthe multiple crack problems in plane elasticity. Regularizationprocedures are also investigated. For the solution of the integralequations, the relevant quadrature rules are addressed. A varietyof methods for solving the multiple crack problems is introduced.Applications for the solution of the multiple crack problems arealso addressed. The concept of the modified complex potential(MCP) is emphasized, which will extend the solution range, forexample, from the multiple crack problem in an infinite plate tothat in a circular plate. Many multiple crack problems areaddressed. Those problems include: (i) multiple semi-infinitecrack problem, (ii) multiple crack problem with a general loading,(iii) multiple crack problem for the bonded half-planes, (iv)multiple crack problem for a finite region, (v) multiple crackproblem for a circular region, (vi) multiple crack problem inantiplane elasticity, (vii) T-stress in the multiple crackproblem, and (viii) periodic crack problem and many others. Thisreview article cites 187 references. 相似文献