Sharif Digital Repository

Recent developments in technology resulted in the design of functionally graded materials (FGM) in which properties can be changed gradually. One of the applications of these materials is in the pressure vessels. These materials can be used in a manner which minimize the heat loss and corrosion and maximize the strength. Most of the vessels include a cylinder and a hemispherical cap which used for the storage of liquid or gas. The vessels should be strength enough to handle high pressure as well as base vibration due to earthquake. Static and dynamic analyses of these structures must be performed prior to any application. In this project by utilizing finite element method and cylindrical... 

Experimental identification (EI) of aircraft static and dynamic characteristics is usually performed for design process verification, its compliance against the existing regulations as well as to extraction of its exact stability and performance characteristics. EI is mostly performed via flight and/or wind tunnel testing of a scaled model of the aircraft under scrutiny. In this regard, the purpose of this thesis is design and development of a 5DoF Table Top Platform (TTP) for Aircraft transfer function identifications as well as some of its key derivatives. The proposed TTP can also function as the motion part of a miniature simulator. The PPT is designed in two parts that is comprised of... 

In urban rail (subway) substations, high voltage dc (750 V) is usually used to feed the traction motors of the wagons. This type of feeding raises issues, including the creation of stray currents in different parts of the structure. The cause of the stray current is the voltage difference between the two points of the rails, caused by the current flowing inside the rails. These currents accelerate the corrosion process in and around metallic equipment. One of the most dangerous issues is the corrosion of gas pipes near the subway that has caused disasters in the past. The stray current cannot be eliminated and its maximum reduction requires high costs. For this reason, different standards... 

Today, factors such as the growing energy consumption in the world, followed by the reduction of fossil fuel reserves, and more importantly, the global warming phenomenon due to excessive consumption of fossil fuels have caused attention towards clean energy, especially solar energy, to increase significantly. Researchers throughout the world are looking for solar cells with high efficiency and stability, and of course affordable. In today's world, one of the materials that has grabbed the researchers' attention is perovskite. The reason behind this is that in the last decade, there has been a significant increase in the efficiency of perovskite solar cells to surpass that of Silicon solar... 

Due to the high level abstraction inherent in most formal specifications and the need to formally specify and develop nondeterministic systems, such as concurrent, probabilistic, and game-like ones, nondeterminism comes into formal specifications inevitably. As it will be shown in this thesis, after developing programs constructively from implicitly nondeterministic specifications, which have been written in the CZ (constructive Z) specification language, only one of the allowable, specified behaviors will appear in final programs. In this way, the implementer will be provided with only one of the possible implementations that is not necessarily the best one. When the nondeterminism involved... 

Rapid growth of technology and the increase in availability of fast communication means caused transportation planners to pay attention to solutions of demand management with an aproach to information technology. Replacement of traditional shopping with internet shopping can be seen as a suitable solution to reduce traffic and polution. Purpose of this research is to probe teleshopping choice and the frequency of doing that, simultaneously, using copula model as the most common aproach of joint models in recent years. In this research, the binary logit model is used to build the model for teleshopping choice and the order logit model is used to build the frequency model. The data sample is... 

One of the most crucial methods to Ensure correct software performance is testing. On this ground, one of the most critical discussions regarding software testing is the effectiveness of a test suite. Program state coverage is a criterion for determining the effectiveness of a test suite. This criterion indicates the number of program states that are executed for the lines. Since the total number of program states cannot be calculated to measure coverage, this criterion proposes a fixed number of 10 to measure program state coverage. Also, according to calculations for the program state in the execution of each line, the time complexity of this criterion is high. In this thesis, providing... 

Identifying the success factors of construction projects is one of the most important issues in project management. Lack of sufficient and comprehensive knowledge of project success factors makes it difficult to control, monitor and operate projects. Therefore, identifying the factors influencing the failure or success of projects according to the type of projects by managers, employers and executives can provide a good framework for evaluating and reviewing project outputs for them. Also, recognizing the success factors of projects can help to manage the appropriate allocation of resources throughout the life of the project. The result of this study can increase the existing knowledge about... 

In recent years, there have been many studies aimed at finding program defect using information of previous ones. These studies, by using the program text, previous bugs, and information related to version control and project management systems create an defect prediction model to find other defect prone areas in the program. The output of defect prediction methods is part of the program’s text, which is likely to have defects. Considering that the result of this method is just the text of the program and does not provide any extra information for finding defects to the user, these methods have not yet been applied to the software industry. On the other hand, by spreading the use of Q & A... 

The abstract is the most important section of the thesis because many readers limit most of their reading to abstracts, saving in-depth reading for specific theses. It should give the reader a "preview" of what's to come. The abstract should emphasize new and important aspects of the study or observations. The purpose of the abstract is to allow researchers to decide whether or not to read the whole thesis. The abstract is what researchers read first to decide if the thesis is important, interesting, and it allows them to assess the relevance of a thesis to their own research, without having to read the entire thesis. Thus, it is crucial that the abstract both summarize succinctly the key... 

In this project, inverse emulsion polymerization (IEP) modeling of poly acrylamid (PAM) using population balance equations (PBEs) has been performed. For this porpuse zero-one and pseudo- bulk models and hybrid model including the zero-one and pseudo- bulk are applied based on the process conditions. The effects of surfactant steric barrier and surfactant reaction with radicals including monomeric radicals on the radical entry rate into the particle have been taken into account for these models. In the modeling, coagulation phenomenon was included by considering the effects of non-DLVO forces such as hydration and steric forces in addition to the DLVO forces. Simulation results for zero-...