Stress concentration around a hole in a radially inhomogeneous plate

The stress concentration factor around a circular hole in an infinite plate subjected to uniform biaxial tension and pure shear is considered. The plate is made of a functionally graded material where both Young’s modulus and Poisson’s ratio vary in the radial direction. For plane stress conditions, the governing differential equation for the stress function is derived and solved. A general form for the stress concentration factor in case of biaxial tension is presented. Using a Frobenius series solution, the stress concentration factor is calculated for pure shear case. The stress concentration factor for uniaxial tension is then obtained by superposition of these two modes. The effect of nonhomogeneous stiffness and varying Poisson’s ratio upon the stress concentration factors are analyzed. A reasonable approximation in the practical range of Young’s modulus is obtained for the stress concentration factor in pure shear loading.     

An improved method for ranking alternatives in multiple criteria decision analysis

Scoring rules are an important disputable subject in data envelopment analysis (DEA). Various organizations use voting systems whose main object is to rank alternatives. In these methods, the ranks of alternatives are obtained by their associated weights. The method for determining the ranks of alternatives by their weights is an important issue. This problem has been the subject at hand of some authors. We suggest a three-stage method for the ranking of alternatives. In the first stage, the rank position of each alternative is computed based on the best and worst weights in the optimistic and pessimistic cases, respectively. The vector of weights obtained in the first stage is not a singleton. Hence, to deal with this problem, a secondary goal is used in the second stage. In the third stage of our method, the ranks of the alternatives approach the optimistic or pessimistic case. It is mentionable that the model proposed in the third stage is a multi-criteria decision making (MCDM) model and there are several methods for solving it; we use the weighted sum method in this paper. The model is solved by mixed integer programming. Also, we obtain an interval for the rank of each alternative. We present two models on the basis of the average of ranks in the optimistic and pessimistic cases. The aim of these models is to compute the rank by common weights.     

Infinitely many solutions for perturbed difference equations

Using variational methods and critical point theory, the existence of infinitely many solutions for perturbed nonlinear difference equations with discrete Dirichlet boundary conditions is ensured.     

Ferric Perchlorate: An Efficient Reagent for Regio- and Stereoselective Alcoholysis and Hydrolysis of Epoxides

Regio- and stereoselective ring opening reaction of epoxides is achieved efficiently by aliphatic alcohols and water in the presence of catalytic amounts of ferric perchlorate.     

Finite element method for conserved phase fields: Stress-mediated diffusional phase transformation

Phase-field models with conserved phase-field variables result in a 4th order evolution partial differential equation (PDE). When coupled with the usual 2nd order thermo-mechanics equations, such problems require special treatment. In the past, the finite element method (FEM) has been successfully applied to non-conserved phase fields, governed by a 2nd order PDE. For higher order equations, the convergence of the standard Galerkin FEM requires that the interpolation functions belong to a higher continuity class.     

A semi-analytic analysis of shape memory alloy thick-walled cylinders under internal pressure

In this paper, a new method for analysis of the pseudoelastic response of shape memory alloy thick-walled cylinders subjected to internal pressure is proposed. Two cases of short and long cylinders are considered by assuming the plane stress and plane strain conditions. In each case, a three-dimensional phenomenological SMA constitutive model is simplified to obtain the corresponding two-dimensional constitutive relations. The cylinder is partitioned into a finite number of narrow annular regions, and appropriate assumptions are made in order to find a closed-form solution for the equilibrium equations in each annular region. The global solution is obtained by enforcing the stress continuity condition at the interface of the annular regions and imposing the boundary conditions. Several numerical examples are presented to demonstrate the efficiency of the proposed method, and the results are compared with three-dimensional finite element simulations.     

A color constancy method using fuzzy measures and integrals

The ability of measuring colors of objects, independent of light source illumination, is called color constancy which is an important problem in machine vision and image processing fields. In this paper, we propose a new combinational method that is based on fuzzy measures and integrals to estimate the chromaticity of the light source as the major step of color constancy. The basic idea of the proposed method is that there are color constancy methods with some similarities in their structure and the way they are applied. The proposed method works with the help of assigning fuzzy measures to these methods and their combinations and computing the Choquet fuzzy integral. To approve the proposed method, we selected four well known algorithms and their results were combined by the proposed approach. In selecting these methods, it was tried to choose the ones which had better performance in compare to other methods, however the proposed method can be applied on any other methods just by adjusting its parameters. It is shown in this article that proposed approach performs better than other proposed methods for color constancy most of the time.     

A Krein quantization approach to Klein paradox

In this paper we first introduce the famous Klein tization approach and taking the negative modes into account densities could be achieved without confronting any paradox. paradox. Afterwards by proposing the Krein quan- , we will show that the expected and exact current     

Kinetic-Spectrophotometric Determination of Tellurium (IV) by Its Catalytic Effect on the Reduction of Thionine by Sodium Sulfide in Cationic Micellar Medium

A simple and highly sensitive method is proposed for the determination of Te(IV) by its catalytic effect on the reduction of thionine by sodium sulfide in the presence of cetyl trimethyl ammonium bromide as a micelle media. The reaction was monitored spectrophotometrically by measuring the decrease in absorbance of thionine at 600 nm with a fixed time of 0.5-2.5 min from initiation of the reaction. Tellurium can be measured in the concentration range of 0.6-500.0 ng/mL, with a limit of detection of 0.3 ng/mL Te(IV). The influence of more than thirty potential interfering ions was studied on the determination of tellurium. The relative standard deviation for ten replicate measurements of 0.020 and 50.0 ng/mL Te(IV) was 2.1 and 1.9%, respectively. The method was applied for the determination of tellurium in synthetic samples.