Opportunities and challenges of electrochromic phenomena in transition metal oxides

During the past two decades, electrochromic phenomena in transition metal oxides have been very widely studied. This unique phenomenon of electrically induced reversible coloration and charge storage in this films has diverse applications that range from information display to neural networking in optical computation. Electrochromic devices using metal oxides can be classified into two broad categories (1) all-solid-state systems, and (2) semi-solid systems involving wet electrolytes. The principles underlying the operation of both systems appear quite similar, but there remain both scientific and technological issues that are poorly understood. In this paper we briefly discuss some of the opportunities and challenges for the application of electrochromic phenomena in transition metal oxides.     

Optimum shapes of tire‐treads for avoiding lateral slippage between tires and roads

Optimum design of tire‐tread sections is an important practical issue. However, useful study of the problem that can suggest a reliable guideline for determining the optimum tread sections had hardly been made in the past. The present paper describes a new analysis of the state of stresses in tire‐tread sections in contact with the road surface, taking special care of the boundary conditions. Based on the analysis, a method is proposed to determine the optimum tread shapes for avoiding lateral slippage between tires and roads. The displacement potential function formulation, an ideal mathematical model for the practical stress problems, has been used in conjunction with finite‐difference method of solution. For the present analysis, lateral slipping in absence of frictional resistance as well as the no‐slip conditions of the tire‐tread contact surface have been considered along with a large number of tread aspect ratios. The present computational approach proves to be a powerful tool for determining the optimum tread shapes for avoiding the lateral slippage of tire‐treads. Copyright © 2005 John Wiley & Sons, Ltd.     

A constraint consensus memetic algorithm for solving constrained optimization problems

Constraint handling is an important aspect of evolutionary constrained optimization. Currently, the mechanism used for constraint handling with evolutionary algorithms mainly assists the selection process, but not the actual search process. In this article, first a genetic algorithm is combined with a class of search methods, known as constraint consensus methods, that assist infeasible individuals to move towards the feasible region. This approach is also integrated with a memetic algorithm. The proposed algorithm is tested and analysed by solving two sets of standard benchmark problems, and the results are compared with other state-of-the-art algorithms. The comparisons show that the proposed algorithm outperforms other similar algorithms. The algorithm has also been applied to solve a practical economic load dispatch problem, where it also shows superior performance over other algorithms.     

Generation of Arylated Quinones by Iron‐Catalyzed Oxidative Arylation of Phenols: Formal Synthesis of Phellodonin,Sarcodonin ε, Leucomelone and Betulinan A

Biologically and pharmaceutically relevant arylated quinones (Quin‐Ar) have been synthesized via direct C H arylation of a variety of phenols using arylboronic acids. An inexpensive, environmentally friendly iron catalyst, ferric sulphate, Fe₂(SO₄)₃, was employed in this operationally simple and efficient method.

     

Constrained Efficient Global Optimization for Pultrusion Process

Composite materials, as the name indicates, are composed of different materials that yield superior performance as compared to individual components. Pultrusion is one of the most cost-effective manufacturing techniques for producing fiber-reinforced composites with constant cross-sectional profiles. This obviously makes it more attractive for both researchers and practitioners to investigate the optimum process parameters. Validated computer simulations cost less as compared to physical experiments, therefore this makes them an efficient tool for numerical optimization. However, the complexity of the numerical models can still be “expensive” and forces us to use them sparingly. These relatively more complex models can be replaced with “surrogates,” which are less complex and are therefore faster to evaluate representative models. In this article, a previously validated thermochemical simulation of the pultrusion process has shortly been presented. Following this, a new constrained optimization methodology based on a well-known surrogate method, i.e., Kriging, is introduced. Next, a validation case is presented to clarify the working principles of the implementation, which also supports the upcoming main optimization test cases. This design problem involves the design of the heating die with one, two, and three heaters together with the pulling speed. The results show that the proposed methodology is very efficient in finding the optimal process and design parameters.     

MHD non-Darcian mixed convection heat and mass transfer over a non-linear stretching sheet with Soret-Dufour effects and chemical reaction

A study has been carried out to analyze the effects of variable thermal conductivity, Soret (thermal-diffusion) and Dufour (diffusion-thermo) on MHD non-Darcy mixed convection heat and mass transfer over a non-linear stretching sheet embedded in a saturated porous medium in the presence of thermal radiation, viscous dissipation, non-uniform heat source/sink and first-order chemical reaction. The governing differential equations transform into a set of non-linear coupled ordinary differential equations using similarity analysis. Similarity equations are then solved numerically using shooting algorithm with Runge-Kutta Fehlberg integration scheme over the entire range of physical parameters. A comparison with previously published work has been carried out and the results are found to be in good agreement. Graphical presentation of the local skin-friction coefficient, the local Nusselt number and the local Sherwood number as well as the temperature profiles show interesting features of the physical parameters.     

Spectroscopic study of Y210C lambda-repressor: implications for cooperative interaction

The development of a percutaneous artificial internal organ system requires a reliable biocompatible connection between the external environment and the inside of the human body. Such is necessary for the success of a permanent left ventricular assist device. However, the search for a satisfactory interface at the epidermal level has proven to be difficult. Carbon has been proposed for this application, but its texture does not typically promote ingrowth from surrounding tissue. We have therefore employed a new processing method to produce a fine trabecularized carbon implant. The method for preparing the implant involves infiltrating low temperature pyrolytic carbon into the surface of a carbon core which is wrapped with carbon fabric. This results in a tightly woven porous structure of carbon (carbon fiber diameter: 35-50 microm, maximal pore size >200 microm) with gradually increasing porosity from 15-75%. We implanted test samples percutaneously in a calf for in vivo histological evaluation. Thirty days after implantation epidermal downgrowth was minimal. Microscopic analysis revealed that a thin fibrous capsule surrounded the implant, and mature connective tissue with accompanying blood vessels filled the pores of the fine trabecularized carbon layer. From these results we suggest that fine trabecularized carbon is ideally suited for a percutaneous device system in a permanent left ventricular assist device.