Effect of Landauer's blowtorch on the equilibration rate in a bistable potential

Kinetic aspect of Landauer's blowtorch effect is investigated for a model double-well potential with localized heating. Using the supersymmetric approach, we derive an approximate analytical expression for the equilibration rate as function of the strength, width and the position of the hot zone, and the barrier height. We find that the presence of the hot zone enhances the equilibration rate, which is found to be an increasing function of the strength and width of the hot zone. Our calculations also reveal an intriguing result, namely, that placing the hot zone away from the top of the potential barrier enhances the rate more than when it is placed close to it. A physically plausible explanation for this is attempted. The above analytical results are borne out by detailed numerical solution of the associated Smoluchowski equation for the inhomogeneous medium.Comment: 15 pages in LaTeX format and 6 figures in postscript E-Mail : [email protected] [email protected]

Multi-scale modeling of damage and delaminations failure in ceramic matrix composites

Ceramic Matrix Composite (CMC) materials are high-temperature material of particular interest to aircraft engine manufacturers as they have the potential to provide better thermal efficiency at a lower weight compared to conventional metallic materials. As these materials are being inserted into service it is essential to understand their damage and failure mechanisms to ensure designs with sufficient margins as well as their long-term durability. High-fidelity analytical and computational models of CMC failure processes can enable robust design of CMC components. This talk will focus on multi-scale modeling of elastic behavior as well as ply-damage and delamination fracture in CMCs developed over many years under several AFRL funded programs. The effects of defects as well as issues in scaling the behavior from coupon-scale to component-scale will be discussed via analysis of test coupons and representative sub-elements

Mechanics-Based Modeling Approach for Rapid Prediction of Low Velocity Impact Damage in Composite Laminates

A mechanics-based modeling approach is developed to rapidly predict damage in polymer matrix composites resulting from a low velocity impact event. The approach is incorporated into a computer code that provides an efficient means to assess the damage resistance for a range of material systems, layup configurations, and impact scenarios. It is envisioned that the developed approach will aid in early design and analysis of composite structures where sizing and layup decisions must be made, and evaluating the feasibility of a large number of laminate configurations using numerical approaches such as finite element analysis (FEA) is prohibitively expensive. Therefore, the goal of the modeling approach is to predict the impact damage size given the laminate configuration and impact scenario. This information can then be used to determine the residual strength of the material. To be useful in such a context, the tool is designed to run quickly (<2 minutes) to allow a large number of design cases to be investigated. The results presented demonstrate that the model is capable of efficiently predicting low velocity impact damage size, shape, and location within an acceptable accuracy suitable for preliminary design and analysis of composite structures

A Study on Ajax in Web Applications with Latest Trends

The Web was an interesting but not particularly exciting tool used by scientific researches - until 1993. In olden days the web technology used for creating web pages is HTML (Hyper Text Markup Language). Now a days the most efficient and advanced Web technologies using are XML (extensive Markup Language), DOTNET and ASP.NET. A Web browser is a software application designed to find hypertext documents on the Web and then open the documents on the users computer. The Web browser displays a Web page as specified by the pages underlying HTML

Comparative Study of PID Based VMC and Fuzzy Logic Controllers for Flyback Converter

In this paper performance of flyback converter by using PID controller and Fuzzy controller are studied, compared and analyzed. The above study is done for 200W, 230V A.C input 48V DC output. Design of fuzzy controller is based on the heuristic knowledge of converter behaviour, and tuning of fuzzy inference requires some expertise to minimize unproductive trial and error. The design of PID control is based on the frequency response of the converter. For the DC-DC converters, the performance of the fuzzy controller was superior in some respects to that of the PID controller. The fuzzy controller is easily to develop, they cover a wide range of operating conditions, and they are more readily customizable in natural language terms. Simulation is done in Matlab environment to show the performance variations of above mentioned converters using both Fuzzy & PID controllers