Generalized couette flow of a dipolar fluid between two parallel plates

Résumé Dans ce travail, on présente une solution du problème de l'écoulement d'un fluide dipolaire entre deux plaques parallèles, dont l'une est en mouvement et l'autre fixe, en présence d'un gradient de pression. On trouve qu'il n'y a pas d'effet dipolaire sur l'écoulement si le gradient de pression n'est pas appliqué, et que pour un fluide dipolaire avec =0, étant le rapport entre l'espace des deux plaques et la constante dipolaire du fluide, le profil de vitesse n'est pas affecté par le gradient de pression.     

A fluorescently labeled dendronized polymer-enzyme conjugate carrying multiple copies of two different types of active enzymes

A hybrid structure of a synthetic dendronized polymer, two different types of enzymes (superoxide dismutase and horseradish peroxidase), and a fluorescent dye (fluorescein) was synthesized. Thereby, a single polymer chain carried multiple copies of the two enzymes and the fluorescein. The entire attachment chemistry is based on UV/vis-quantifiable bis-aryl hydrazone bond formation that allows direct quantification of bound molecules: 60 superoxide dismutase, 120 horseradish peroxidase, and 20 fluorescein molecules on an average polymer chain of 2000 repeating units. To obtain other enzyme ratios the experimental conditions were altered accordingly. Moreover, it could be shown that both enzymes remained fully active and catalyzed a two-step cascade reaction.     

A review on design criteria for vortex tubes

In this study, the past investigations of the design criteria of vortex tubes were overviewed and the detailed information was presented on the design of them. Vortex tubes were classified and the type of them was described. All criteria on the design of vortex tubes were given in detail using experimental and theoretical results from the past until now. Finally, the criteria on the design of them are summarized.     

An almost second order uniformly convergent scheme for a singularly perturbed initial value problem

In this paper a nonlinear singularly perturbed initial problem is considered. The behavior of the exact solution and its derivatives is analyzed, and this leads to the construction of a Shishkin-type mesh. On this mesh a hybrid difference scheme is proposed, which is a combination of the second order difference schemes on the fine mesh and the midpoint upwind scheme on the coarse mesh. It is proved that the scheme is almost second-order convergent, in the discrete maximum norm, independently of singular perturbation parameter. Numerical experiment supports these theoretical results.     

A clamped rectangular plate containing a crack

In this paper the general problem of a rectangular plate clamped along two parallel sides and containing a crack parallel to the clamps is considered. The problem is formulated in terms of a system of singular integral equations and the asymptotic behaviour of the stress state near the corners is investigated. Numerical examples are considered for a clamped plate without a crack and with a centrally located crack, and the stress intensity factors and the stresses along the clamps are calculated.     

A cracked beam or plate transversely loaded by a stamp

In this paper the problem of an infinite elastic beam or a plate containing a crack is considered. The medium is loaded transversely through a stamp which may be rigid or elastic. The problem is a coupled crack-contact problem which cannot be solved by treating the crack and contact problems separately and by using a superposition technique. First the Green's functions for the general case are obtained. Then the integral equations for a cracked infinite strip loaded by a frictionless stamp are obtained. With the question of fracture in mind, the primary interest in the paper has been in calculating the stress intensity factors. The results are given for a rigid flat stamp with sharp edges and for an elastic curved stamp. The effect of friction at the supports on the stress intensity factors is also studied and a numerical example is given.     

Review of peridynamics for multi-physics coupling modeling

广义来说, 近场动力学(peri-dynamics,PD)是假设每个物质点在承受一定范围内的非接触相互作用下,研究整个物理系统演化过程的理论,为涉及非连续和非局部相互作用的问题提供了一个统一的数学框架,具有广泛的适用性.在简要介绍诸多工程对于多物理场模型和数值计算软件的迫切需求后,针对现有商用软件在处理结构非连续演化问题时遇到的瓶颈,引入近场动力学理论和方法. 概述近场动力学固体力学模型,系统阐述近场动力学扩散模型和近场动力学多物理场耦合建模的研究现状和进展,主要涉及电子元器件、电子封装和岩土工程领域的多物理场耦合建模,包括热--力、湿--热--力、热--氧、热--力--氧、力--电、热--电、力--热--电、多孔介质的水--力流固相互作用等非耦合、半耦合与完全耦合模型,强调发展耦合方程数值解法的重要性.最后对扩散问题和多物理场耦合问题的近场动力学理论模型、数值算法和工程应用做进一步展望.     

A class of similarity solutions for radial motions of compressible hyperelastic spheres and cylinders

A class of similarity solutions is obtained for radial motions of spherical and cylindrical bodies made of a certain type of compressible hyperelastic materials. The equations satisfied by the infinitesimal generators of the symmetry group of the unified governing first order field equations for spheres and cylinders are found. It is shown that these equations admit a special class of solutions which generate a five-parameter group of transformations. The form of the strain energy function corresponding to the resulting symmetry group is evaluated. The similarity variable is determined and ordinary differential equations satisfied by similarity solutions are obtained. Numerical solutions are given for a Ko material which falls into the class of admissible materials.     

Redox Amination Scope of Benzylic Ketones with Indoline: Synthetic and Mechanistic Insights

Bi(NO₃)₃·5H₂O‐Catalyzed redox amination scope and mechanistic insights of benzylic ketones with indoline are discussed. The experimental results demonstrate that the formation of N‐alkyl‐substituted indole/indoline derivatives over typically competitive redox and reductive amination processes is depending upon the reaction condition for the benzylic ketones.     

Fabrication and characterization of calix[4]arene Langmuir–Blodgett thin film for gas sensing applications

Microwave irradiation has been found to be a highly efficient method for etherification of p-tert-butylcalix[4]arene with alkyl bromides or ditosylate. The corresponding products were obtained as a pure form in modest yield within short reaction time when the reactions were performed under microwave irradiation.