Sharif Digital Repository

In this thesis, a general survey and reviewis done about the models that go beyond the standard model. Even it contains the great subjects like quantum gravity and alternative Quantum field theories. In addition to them, we concentrate on the supersymmetry that is one of the most important subjects in the beyond the standard model. Recently, the validityof supersymmetry has confronted a lot of controversy. This motivates reconsideration of many supersymmetric models. So we survey the main motivations and problems of the supersymmetry and finally we discuss some possible solutions to the problems  

Destruction of green lands, especially forests, is one of the most common forms of environmental degradation. Meanwhile, political institutions can play an important role in protecting or destroying the environment, especially forests. The creation of town and village councils as a change in political institutions and decentralization can have an impact on the environment. Land use change, implementation of development projects and the task of overseeing the implementation of environmental protection laws are among the duties and powers of councils that affect the coverage of various areas. At different eras, town and village councils’ elections have been annulled or dissolved in a... 

In this research, the first attempt was made to increase the thickness of the absorbent layer and increase the size of the absorbent layer crystals and minimize the cavities of this layer. this attempt resulted in the synthesis of absorbent layer with a thickness of about one micrometer and with low cavities. then, an attempt was made to crystallize the buffer layer and form the bond with the absorbent layer. these efforts led to the synthesis of a cadmium sulfide layer with a high carrier density. in this study, cadmium sulfide and cadmium zinc sulfide and indium sulfide were used to make the cell. then we could synthesizing window layer with low resistance.at end, we made superstrate... 

The purpose of this study is the fabrication and characterization of ZnO nano particles and the application of ZnO in solar cells. Therefore, firstly we fabricate the high stable solution of ZnO nano particles and then characterize ZnO nano particles. In addition, we study sulfurzation and selenization of zinc oxide thin films. We use ZnO nano particles for fabrication of transparent conductive films. Transparent conductive films have many applications such as touch panels, displays and solar cells. The most applicable transparent conductive electrode is indium tin oxide , which is the most expensive layer in solar cells. But silver nanowires has some challenges such as high surface... 

Robust model predictive control(RMPC) is a control strategy that has been widely adopted in industry and academic researches.In this project we have modified robust nonlinear model predictive control using SOS and dynamic feedback. In this control strategy we will linearize the nonlinear model of the system about it’s operating point. We will consider the error of linearization as an uncertainty and find an upper bound for uncertainty. Then we will change control objective to minimizing this upper bound. The most advantage of changing the control objective is that nonlinear system results a non-convex optimization problem but this strategy terminates a convex optimization problem. To find... 

In recent years, the use of thin film solar cells has been widely considered due to the ability of their solution-based coatings. One of these is the chalcopytie solar cell copper indium gallium di-selenide (CIGS). The absorber layer of copper indium gallium diselenide was carried out by a spray pyrolysis method. then by using a chemical bath deposition, a buffer layer was fabricated to form the p-n junction. Subsequently, silver nanoparticles and zinc oxide alumina sputtering were used to form a transparent conductive film. with using the substrate Molybdenum and by optimizing the test conditions, such as temprature and deposition time to adjust thickness of layers, Cell with an... 

In this study, the effects of treatment time and power of Low-frequency (LF) O2 plasma has been investigated for the surface treatment of polyethersulfone (PES) gas separation membranes. PES membranes prepared using dry/wet phase inversion using ternary mixtures containing 1-methyl-2-pyrrolidone (NMP) as solvent, water as non-solvent. The optimum polymer concentration was 32 wt.% , 61 wt.% and 7 wt.% for PES,1-methyl-2-pyrrolidone and water respectively. Pure CO2 and CH4 gas permeation measurements were performed before and after plasma treatment. After treatment gas permeances of around 0.81 GPU for CO2, and 0.073 GPU for CH4 with selectivities of around 11.23 for CO2/CH4 were obtained.... 

Application of canard next to the wing have been widely used in military industry for decades. Although it’s most application is in supersonic flying objects, It has to do it’s duty in lower air speeds too. The aim of this study was to investigate the influence on the wing due to the presence of canard in supersonic flow regime. But because of the importance of the issue, significant attempts has been conducted in subsonic flow regime. High research volume, Absence of a comprehensive theory in this branch and the local defense industry demand as a developing country on the other hand, delivers the importance and applicability of the subject. Another issue of importance is that the... 

Optical neural networks (ONNs) are custom optical circuits promising a breakthrough in low-power, parallelized, and high-speed hardware for the growing demands of artificial intelligence applications. All-optical implementation of ONNs has proven burdensome chiefly due to the lack of optical devices that can emulate the neurons' non-linear activation function, thus forcing hybrid optical-electronic implementations. Moreover, ONNs suffer from a large footprint in comparison to their electronic (CMOS-based) counterparts. Utilizing virtual optical neurons in the time or frequency domain can reduce the number of required physical neurons, but an all-optical activation function is still required,... 

Shoreline monitoring and predicting has a very important role for policymakers and managers of coastal areas in future planning and achieving sustainable development. In this regard, to monitor the shorelines and predict its changes, a study has been conducted considering the effect of tides. In this study, the shoreline obtained from satellite images has been modified by using slope maps, slope direction and tidal data. Then these lines were monitored using the Digital Shoreline Analysis System (DSAS) and finally Bruun's rule along with the RCP scenario was used to predict changes in the shoreline. In this research, the coastlines of Bushehr Province in the Persian Gulf have been selected... 

Accurate modeling of clutter and detection of low observable targets within clutter are the major problems in radar signal processing applications. Recently, fractal geometry is applied to the analysis of high range resolution radar sea clutters. The intrinsic difference in the fractal dimension between sea clutter and the echoes from targets is extracted and used to detect targets. The box-counting method is widely used to estimate fractal dimension but it has some drawbacks never or rarely considered in literature. We explain the drawbacks and propose a new fractal dimension based detector to increase detection performance in comparison with traditional detectors. Both statistically... 

The synthetic aperture radar (SAR) is a microwave imaging radar that achieves high resolution while taking advantage of pulse compression technology and the Doppler effect. In typical radar systems, in order to obtain a good azimuth resolution, one should use an antenna with big aperture. However this is not possible in many cases. SAR has overcome this problem by moving the antenna and so making a synthetic aperture. In inverse SAR (ISAR) the radar antenna is static and synthetic aperture is created by the movement of target. Typical SAR imaging aims at the static targets and when the target is moving, it does not operate well. When detecting moving targets by SAR, both radar and target are... 

Shallow geothermal energy is a renewable and sustainable form of energy that has the potential to help alleviate the growing climate and energy crisis. The most common system used to extract shallow geothermal energy is the ground source heat pump (GSHP) system. The concept of using underground structures in exploiting shallow geothermal energy for space heating and cooling has received increasing attention. This study focuses on the use of geothermal tunnels as a means of extracting shallow geothermal energy.This research examines the effects of different heat transfer mechanisms, and highlights the effects of this phenomenon by focusing on the effects of natural convection around the... 

This study aims to propose a new correlation between in-situ horizontal stress and cone tip resistance in soils. Knowing the field in-situ stress state condition has an important role in stability assessment and stress-deformation analysis in a common geotechnical system. Although vertical stress could be measured easily, horizontal stress is still known as challenging work. Due to the difficulty in sampling undisturbed sand specimens, in-situ tests have been proposed in the previous literature to investigate the different characteristics of this soil. Cone Penetration Test (CPT) is one of the most used and accepted soil methods for soil investigation, identifying different soil parameters... 

This thesis presents turbulent partially premixed combustion modeling behind a bluff-body by using the Flamelet Generated Manifold. The objective of the present work is to develop a 4D FGM program to simulate partially premixed combustion at a reasonable computational cost. Pre-tabulated data of this manifold is obtained by using a correlated joint PDF. An in-house code is developed to build a pre-tabulated library in conjunction with a correlated PDF. Also, an exclusive OpenFOAM solver is created by employing the PIMPLE algorithm. This solver provides the link of the computational domain with the pre-tabulated chemistry. This program is used to simulate Cambridge-Sandia stratified burner... 

While Cloud providers face problems during providing services to their clients, such as lack of resources or increasing idle resources in low workload; they can share their resources with other providers by participating in Cloud Federations, and take advantage of Cloud Computing benefits like high scalability and resource extension. Moreover collaborating Cloud Federations expands Geographical area of providers. The Resource Allocation Problem has been considered in many researches, but in fields like Cloud environment and Federated Clouds it comes with complications. This thesis analyzes an optimized mechanism based on game theoretic approach for Resource Allocation Problem in Federated... 

Token offerings, one of the new methods of financing in the blockchain industry, have provided startups with significant opportunities. In previous studies, most of the factors that determine the success of an initial offering have been examined, and operational performance has been less studied. In this study, the relationship between environmental, social, and corporate governance activities on operational performance and adoption has been presented. Previous studies have shown that more attention to environmental, social, and corporate issues leads to a higher amount of capital raised in the offering. We also address these issues among crowdfunding platforms, which attract more... 

In recent years, with the growth of industrial societies, the amount of energy consumption in the world has been increasing. On the other hand, the most consumed energy sources in the world are non-renewable energy sources. For this reason, governments and industries have invested to facilitate and make renewable energy sources cheaper. One of these renewable energies is geothermal energy, which is one of the most economical ways to use this energy, using heat exchange systems in piles and foundations. Using a heat exchange fluid, energy piles transfer the heat of the earth's surface to the ground with a lower temperature in the hot seasons of the year and use the thermal energy of the... 

In the current situation, kidney transplantation is the most appropriate and least costly treatment for patients with end-stage renal disease (ESRD). Related or altruistic living donors, as well as deceased donors, are considered as a supply source for donated kidneys. Researches have shown deceased donor kidney may not work as well as a living donor kidney because the deceased donor kidney is outside the donor's body for a longer time. If the donor has an incompatibility with the patient (in terms of the blood group, HLA, etc.), a kidney exchange between the pairs can be used to resolve the issue and make the transplantation possible. Pairs with blood group compatibility have also... 

Considering the environmental pollution caused by the consumption of fossil fuels, replacing clean and renewable energies instead of fossil fuels has become one of the most critical issues across the world. The use of energy geostructures, especially energy piles, to exchange the heat between the superstructures and the ground is one of the approaches for taking advantage of clean energy. In order to maintain the safety and the serviceability of structures built on energy piles, it is necessary to study the effects of heat exchange between energy piles and the ground on the mechanical behavior of energy piles, as well as the effects of various parameters on the interaction between energy...