Sharif Digital Repository

Investigating the behavior of piled-raft foundations is a three-dimensional problem. The shape and location of the piles in the raft as well as the complex interaction of the soil-structure in these foundations should be analyzed in a three-dimensional fashion to indicate the real behavior of this type of foundations. The soil must also be analyzed in a nonlinear state to achieve the correct bearing capacity of these foundations. In this research, a nonlinear 3D analysis was performed using FLAC3D to investigate the behavior of piled-raft foundations, and the effect of various factors such as the length, arrangement and number of the piles, the loading level and the thickness of the raft, on... 

Today, renewable energies such as solar and wind power are replaced to fossil fuel. Wind turbines are two categories; horizontal axis and vertical axis. Vertical axis turbines are not dependent on wind direction and since equipments are installed at the bottom of these turbine towers, maintenance is easy. Among vertical axis turbines, performance of darrieus turbine is better. The aim of this thesis is, analysis and preliminary designing of 1-kilowatt darrieus wind turbine, based on climate of the country, for using in urban environments or areas where there is no economic justification for development of power grid systems. In this regard, statistical data base is made up of vertical axis... 

An important issue in aerospace propulsion systems is the reacting flow analyses, which involve many different concepts and physics including various chemical reactions mechanisms and radiation and convection heat transfer physics. As known, the computer simulation is a powerful tool to analyze the reacting flow physics in various combusting environments. It can suitably provide details of both chemical reaction occurrences and heat transfer physics. In combustion environments, the temperature gradient is noticeably affected by the density gradient. On the other hand, the accurate modeling of density gradients highly affects the computational results. In practice, the density-based methods... 

The cyclometalated platinum(II) complex [Pt(Me)(bhq)(2-vpy)], 2, in which bhq = benzo{h}quinolone, 2-vpy = 2-vinylpyridine, has been prepared by reaction of the cyclometalated complex [Pt(Me) bhq)(SMe2)], 1 with one equiv 2-vinylpyridine. The similar complex [Pt(p-tolyl)(ppy)(2-vpy)], 3 in which ppy = 2-phenyl pyridine, has been prepared from reaction of the platinum(II) complex cis-[Pt(p-MeC6H4)2(SMe2)2] with one equiv 2-phenylpyridine and one equiv 2-vinylpyridine. Reaction of 2 with one equiv Br2 in acetone gave the cyclometalated platinum(IV) complex [Pt(bhq)Me(Br)(NC5H4CHCH2Br)], 4. The structure of the complexes 1-3 were determined using NMR Spectroscopy. The crystal structure of 3... 

Mobile ad hoc networks (MANETs) are the dynamically reconfigurable wireless networks in which mobile nodes communicate with each other without the need for any fixed infrastructure. In these networks mobile nodes are free to move, therefore, network topology changes rapidly. These changes can lead to significant performance degradations in network protocols. To cope with this, a desired solution is to predict movements of mobile nodes. In this way, we can be prepared for changes. This thesis proposes two mobility prediction methods. In both methods, each node uses the information extracted from its own history of movements to predict its future location. Results obtained by applying two... 

The wellbore instability increases the cost of drilling operations due to problems such as pipe sticking and lost circulation, so it is important to find the optimal well path. In this research, building a one-dimensional geomechanical model is investigated, and then the wellbore stability during drilling in different layers is evaluated. The geomechanical model is constructed using available data (well log data, mud logging unit data, and drilling reports) in a study reservoir and the optimal well path is determined by the appropriate inclination and azimuth using the geomechanical properties of the field and the stress regime, taking into account the wellbore stability and shear failure... 

Planning is one of the most important branches of artificial intelligence. The goal of planning is automated production of sequence of actions (plans) for some specified tasks. However the computation done by planners is very time consuming and complicated. Distributing computation is one solution to overcome such difficulties. Distribution divides the load of process between a number of agents and increases robustness. The purpose of this project is to reduce the computational overhead of planning by the means of distributing the planning process between a numbers of planners. In the proposed method, we first divide a classical planning problem to two separate subproblems by decomposition... 

Mobility is one of the most challenging issues in mobile Ad-Hoc networks which has a significant impact on performance of network protocols. To cope with this issue, the protocol designers should be able to analyze the movement of mobile nodes in a particular wireless network. In this thesis, a new framework called Mobility Analyzer has been proposed. At first, Mobility Analyzer categorizes mobility models based on their mobility characteristics; subsequently, it uses mobility metrics for evaluating mobility traces which are collected by GPS or generated by mobility simulators. Finally, Mobility Analyzer recognizes the mobility model of mobility traces based on mobility metrics and measures...