Sharif Digital Repository

Platinum is one of the most used catalysts in refining and petrochemical industries. Also, Platinum uses in other industries like automobile catalytic convertor. As respect to importance of Platinum in these industries, growth of its consumption in recent decades and its very high price, recovery of Platinum is essential. Hence, many of various methods including hydro-metallurgy are applied. In despite of these wide spreading experimental investigations, due to low information about the reactions and the nature of reaction products, a few investigations were done on kinetics of Platinum recovery. A new method that used iodine solution to extract Platinum from spent reforming catalysts was... 

In this research it is aimed to have an investigation on the thermo-mechanical analysis of functionally graded skew plates. In order to analyze the behavior of the skew FGM plates, a constant pressure load as a mechanical load is distributed through the plate. Also the thermo-mechanical load is a combination of this mechanical load and a temperature gradient in upper and lower surface applied as in-phase . Various boundary conditions considered in analysis are combination of simply support and clamped edges including CCCS, CCSS, CCCC. The analysis are based on CPT and the Von-Karman theory is used in the solution. The graded materials are distributed through the thickness according to P-FGM... 

Since the concept of Self-Organized Criticality was introduced in terms of BTW Sandpiles model, its major features have been known as broad power law distributions without any tuning parameters. In some selforganized critical systems like brain and neural networks, some evidences and experiments show a periodic or non-power law distribution of avalanches in addition to the power-law distributions of avalanches. In this thesis we try to observe the same phenomenon in the well-known SOC models, namely the BTW and Manna sandpile models. We have considered small lattice sizes with periodic boundary conditions and a small amount of dissipation. Within such conditions we observe a periodic-like... 

Many different scaling laws are observed in financial data. As an example, the distribution of Log-Return of stock prices obey power law, provided relatively short time intervals are considered. In standard statistical physics, scaling laws are observed in critical phenomena, where the system has long-ranged correlations. Within the same context, to arrive at criticality one has to tune some external parameters, such as the temperature. Yet, there are a group of systems that tend towards criticality through their dynamics. Such systems are called self-organised critical systems.There have been proposed many different mechanisms and models to address why power laws are observed in financial...