Sharif Digital Repository

This thesis extends a probabilistic framework for evaluating the seismic resilience of communities by modeling the transportation system. The framework that is being extended is under continuous development at the Center for Infrastructure Sustainability and Resilience Research (INSURER) at Sharif University of Technology quantifies community resilience by integrating hazard models, risk models, and recovery models within an agent-based simulation. In this framework, the transportation system is modeled by developing a library of probabilistic models to predict the occurrence and intensity of earthquake hazard, damage and capacity of network components, network travel demand, and economic,... 

With occurring severe earthquakes, damages of columns in RC buildings can lead to overall failure and collapse. So retrofitting of such columns that do not comply with the design requirements is necessary to prevent such phenomena. A variety of methods has been introduced so far for retrofitting. The key factors in determining the retrofitting methods are being economic and easily implemented in the design. Confining concrete columns with pre-stressed steel strips is a new technique that is simple and economic. Previous experimental experiments have shown that this method can enhance ductility and overall seismic behavior of such columns.
In the present study three and six story frames... 

Digital image analysis of histological datasets is a currently expanding field of research. Histological images are inherently complex in nature and contain a wide variety of visual information. Graph-based methods have recently gained immense popularity, as these methods can effectively describe tissue architecture and provide adequate numeric information for subsequent computer-based analysis. Graphs have the ability to represent spatial arrangements and neighborhood relationships of different tissue components, which are essential characteristics observed visually by pathologists during the investigation of specimens. In this thesis, we proposed an automatic approach for classification... 

Engineering of properties was previously not possible. With the advent of additive manufacturing, it became possible to produce structures with architected microstructures, known as lattice structures. The popularity of these structures, due to their lightweight and tunable properties, has increased the importance of their optimal mechanical analysis. Since direct analysis of these structures is computationally prohibitive due to their high level of detail, homogenization methods have been proposed as an alternative. Since these methods couldn't capture size effects, higher-order homogenization methods were introduced. However, despite their good accuracy, these methods are still rarely used... 

Reinforcement Learning (RL) is a branch of machine learning that tries to improve agent’s behaviour through interaction with environment and receiving reinforcement signal. As the size of environment increases, decision-making would be more difficult and learning time will increase. On of the main approaches for decreasing learning complexity is to define skills. Skill is a behavioural unit consists of primitive actions. Humans learn and use a lot of skills in their life. Walking, eating, passing the door to reach kitchen and going to airport for travelling are examples of such skills that humans utilize them for daily activities. Agent can learn skills once and then uses them in other... 

One of the most important issues in the petroleum industry, is how to increase the oil production from hydrocarbon reservoirs. The optimum design of an enhanced oil recovery process needs the knowledge on the physical phenomena of the working flow in oil reservoirs. An important aspect of any oil recovery process is the effectiveness of process fluid in removing oil from the rock pores at microscopic scales, in a way that it determines the success or failure of the recovery process. Meanwhile, one of the most important factors on the fluid mobility and as a result the microscopic mobility efficiency is the pressure difference between different phases in narrow paths of porous media. This... 

Magnetohydrodynamic (MHD) flow is concerned with the interaction between the magnetic field and electrically conducting fluid flow. In this investigation, the MHD flow in the duct of magnetohydrodynamic wave energy conversion (MWEC) generator was simulated by use of OpenFOAM software. In the MWEC generator the reciprocating motion of ocean waves lead to electrically conducting fluid flow in the duct of this generator. By applying magnetic field perpendicular to this flow, electric current generate in the fluid. This generator has a higher efficiency compared with other ocean wave energy conversion generators. Firstly, to evaluate accuracy and performance of mhdFOAM code of OpenFOAM, three... 

Fractured reservoirs show a different behavior from common reservoirs because of the existence of a broad network of fractures. This phenomenon makes it necessary to apply special methods for fractured reservoirs in the procedure of reservoir simulation. Since twenty percent of petroleum content in the world is buried in fractured reservoirs, investigating these reservoirs is of great importance.
The first step in simulation of these kinds of reservoirs is to come up with a geometrical model which can be used to take the fracture network influence into account. In the course for reaching such an objective, various models have been developed which are based on specific assumptions and in... 

In this thesis the oil reservoir simulation is carried out by using a combination of fast Multi-scale finite volume method and Streamline method considering gravity effects. In this simulation, the governing equations for incompressible fluid flow in porous media are solved using the IMPES (implicit pressure- explicit saturation) viewpoint. Multi- scale method is rapid (equivalent on coarse-scale methods) and accurate (equivalent on fine-scale methods) in solving the pressure field. Using the pressure field obtained through this way combined with Darcy equation make us able to extract the conservative velocity field. In this study, analytical and numerical Streamline methods are used to... 

In the era of precision cosmology it is desirable to know if the collapse of an overdensity region within a FRW cosmological model leads to a black hole similar to that of Schwarzschild. Even the simple question of an event horizon within a dynamical universe is not a trivial one. This subject of studying collapsing over-densities within an expanding universe is called ”cosmological black holes”. Our aim is to construct such a black hole in the simplest possible scenario and study its similarities and differences to the familiar Schwarzschild one in vacuum. Therefore questions of rotating or charged black holes are not dealt with in our work. We insist, however, that the solution is dynamic... 

In this work, simulation of 3D three-phase naturally fractured reservoirs is studied. Both Dual Porosity and Dual Porosity-Dual Permeability models which are commonly used in commercial softwares such as ECLIPSE and CMG, are utilized. The governing equations include the mass (in Black-oil model) and linear momentum (in Darcy law form) equations, which are converted into pressure equations and a set of transport equations for the saturations and mole fractions of phases. These equations are solved once for the matrix domain and subsequently for the fracture domain. These two set of equations are coupled through transfer functions. The accuracy of computations significantly depends on how... 

In this study, simulation of two-phase water-oil compressible flow in naturally fractured reservoirs is studied. The studied reservoir has a 1D and horizontal ge-ometry that its properties such as porosity and permeability are homogeneous.Dual Porosity and Dual Porosity-Dual Permeability models are employed for simulation of reservoir. Reservoir descriptive equations are conservation of mass and momentum. Conservation of momentum equation is simplified by Darcy law and two-phase fluid flow is simulated with Black-oil model. Discretization of equations is done by finite volume method. In order to solve the equations of two-phase compressible fluid flow, the so-called IMPES (Implicit Pressure...