Sharif Digital Repository

Destruction of a dam is not only an economic disaster but also a catastrophe for the down stream residents. Seepage related problems are the main reasons for the destruction of the embankment dams. Therefore controlling seepage in an earth dam is of great importance.Graphical, experimental,and numerical methods can be applied for analysis of seepage problems in embankment dams.Due to the complexity of geometry and of in homogeneous and/or anisotropic media there are few analytical solutions to porous media problems. Numerical solutions have long played an important role in ground water calculation such as Finite Difference Method (FDM),Finite Element Method (FEM) and Boundary Element Method... 

Recently, a new tool in the study of two-dimensional continuous phase transition was provided by Schramm-Loewner evolution. The main part of SLE is a conformal map which relates growth process of a two-dimensional simple curve to one-dimensional motion on the real axis (so-called Loewner driving function). Time evolution of this map and Loewner driving function is connected via the Loewner differential equation. It turns out that for a certain class of stochastic and conformally invariant curves in two dimensions, the driving function shows Brownian motion in one dimension. Strength point of SLE comes from this fact that all the geometrical properties of such curves is described through a... 

Schramm – Loewner Evolution (SLE) is a framework which helps to classify interfaces in critical models. At criticality two or more phases of the model are separated by an interface. In two dimensions this interface is a simple random curve, which can be addressed by SLE theory. This classification has crucial rule in our understanding of statistical models. In spite of our understanding of2 dimensional statistical models and 1+1dimensional quantum field theories, little workhas been done on these models out of criticality. In this thesis we focus on the Schramm-Loewner Evolutions and conformal field theoriesin vicinity of critical points. To this end we state the theories which the... 

Percolation is a phenomenon that can be found in many physical problems. Additionally, as a statistical model, it has a very rich physics, since many fundamental concepts in the context of critical phenomena and complex systems-such as phase transition, scaling laws etc can be found in the model. Percolation phenomenon can be defined on different lattices. In this thesis we study percolation on small-world networks. In small-world networks, in addition to local bonds that connects the neighbouring sites, there exist some long-ranged bonds that connect cites far from each other. Social networks, some networks of internet or the gene networks are examples of such networks. Therefore, to study... 

Ion channels are present in all cell membranes which are the important part of the performances in regulating the flow across the membrane as well as the signaling. We have investigated the water permeation through carbon nanotube (CNT) membranes as a model for the synthetic ion channels, i.e. peptide nanotube channels (PNCs). The effect of different charge configured CNTs which tailored based on these ion channels on the water permeation has been studied. In addition, the temperature dependence of the permeation using statistical models such as continuous time random walk model (CTRW) via molecular dynamics simulation has been investigated. We have found that there is a jump in the... 

The nature of fluid flow in hydrocarbon reservoirs is very complex because of the complicated sedimentary processes. Proper modeling of distribution of these heterogeneities is crucial, affecting all aspect of fluid flow. The conventional approach to investigating the impact of geological uncertainties on the prediction of reservoir performance is to build a detailed geological model using geophysical, geological and petrophysical data, upscale it and finally perform flow simulation. Because of uncertainties in the data, it is necessary to construct a number of possible geological models and then run flow simulations many times to get a reliable model. This approach is computationally very... 

In drilling the percolation structure reservoirs (such as offshore Channelized reservoirs), one of the most important factors in the effectiveness of wells is drilling permeable areas (Channels), while Channel constraints make it possible for two wells to collide. On the other hand, if the desired reservoir is an offshore reservoir, these restrictions have been increased because usually several wells are drilled near together from one platform. Therefore, proper well collision analysis method is also important in these situations. In this project, anti-collision analysis is performed using the MWD device error model between two or more wells in a static reservoir model with channel... 

An infectious disease can spread through different communities via mobility networks. In this study we address three basic questions related to this matter in the meta-population approximation: firstly, where did the disease start? Secondly, when did the disease start? Thirdly, how does it spread in the network? To answer these questions, we introduce a generic mathematical framework with appropriate physical assumptions and study the spread of diseases. Then, with analytical solutions, we bring up different algorithms in order to answer these three questions. Using these algorithms, we redefine the effective distance and arriving time and unveil the simple geometry of the disease outbreak