Sharif Digital Repository

Due to the increase in greenhouse gases in earth’s atmosphere in recent years and its devastating environmental outcomes, there has been an increase in research trying to reduce these gases especially CO2. Flue gas is one of the most important sources of CO2 emission. Among the many techniques of removal, capturing and CO2 separation from flue gas, physical adsorption by a solid adsorbent is considered as a suitable and economic option. Among the solid adsorbent that are used for adsorption of CO2, Metal-Organic frameworks have many interesting features such as high specific surface area and high internal free volume. Among the Metal-Organic frameworks, MIL-53 (Al) and MIL-101 (Cr) are two... 

Purification of hydrogen, as a clean source of energy has attracted great deal of attention in recent years. Among all available H2 separation methods, membrane technology has been known as the most appropriate way to produce hydrogen with high purity. In this study, we have tried to synthesis and evaluate the performance of perovskite ceramic membranes. The aim of preparing this type of membranes is to use them in separation processes in order to achieve H2 with high purity of >99%. First, general concepts about membranes are discussed. Then synthesis, recognition and performance evaluation of some perovskite membranes are presented. To prepare membranes, ceramic powders are synthesized by... 

Security protocols assure the security of the communications in computer systems using techniques such as cryptographic primitives. However, the usage of such protocols is faced by the lack of fault tolerance, where a minor disruption could cause a destructive damage. Therefore, there is a requirement to assess the reliability of these protocols. In this thesis model checking of timed security protocols is done. Model checking process includes steps that will be modeling protocol with high level and human readable specification language named THLPSL and converting this specification to special kind of timed automata named XTA and model checking will be done with UPPAAL verification tool. We... 

The present study deals with the analysis of Atomic Microscope with crack by making use of Strain Gradient Elasticity theory. Empirical observations represent that in micro dimensions, materials show behaviors, which the classic continuum mechanics theories are not able to explain. Thus, taking advantage of non-classic theories, which are capable of explaining such phenomena or behaviors in analyzing materials in micro dimensions seems necessary and of much significance. In this direction, by applying an Euler-Bernoulli beam assumption and neglecting the shear effects, governing equations and boundary conditions of the problem were obtained via taking advantage of variations in Hamilton... 

Software requirements are changing continuously and hence during software evolution and maintenance, source codes changes are being committed in the software repositories. Reading source codes to understand the changes is a very time consuming and tedious activity. Commit messages contain information about code changes that let developers be aware of the essence of the changes without reading the source codes. Unfortunately, due to the pressure of deadlines and lack of time, developers neglect to write these messages. Commit messages can speed up the process of software understanding for developers and also play an important role in software documentation. Therefore, an automated method for... 

Early failure of pavement is one of the most important problems. As the research conclusions in Iran, Non-conformancity is the most important cause of this problem.Quality management system, Audits and expert systems are the solutions. This research provides an Audit system for quality management system of batch-type asphalt plants as the preliminary solution.A state survey conducted and useful part of state programs had been considered. After developing software, The system functionality has been tested  

From the cache of the personal computers to the main memory unit of SOCs, medical and wearable chips, Static Random Access Memory (SRAM) is widely utilizes. Preferable performance for SRAM varies with regard to the operating field. For instance, high speed access and performance is emphasized in the design of the cache for PCs. In contrast, power consumption and the area of the memory are the key design considerations for SOCs. Hence, the field in which SRAM is used, should be thoroughly studied. SOCs and medical chips suffer limitations in design due to using batteries as the source of energy and SRAMs consume a significant part of total power and occupy a large area on these chips. One of... 

In recent years, economy globalization has led to a major focus on the needs of customers, Moreover globalization has resulted in geographically distributed suppliers across the globe. In such a space, using cloud manufacturing as one of the novel technologies in manufacturing that deals with resource management has been more and more taken into consideration. one of the most important issues in cloud manufacturing is service composition, in which, after receiving customer’s demand, a combination of cloud services is provided to meet customer’s demand. In fact, the customer's need is decomposed in different tasks, each of which is carried out by one (or more) manufacturing plant. the purpose... 

In this research, a pricing-inventory model with multiple interdependent products and stochastic demand is studied. In the relevant literature, there are many researches that are related to optimize the inventory or price independently and also optimizing joint inventory and pricing for single product. But joint optimization of inventory and pricing for multiple interdependent products is relatively new and still there are many potential research gaps in this area. We develop the model with additive and multiplicative demand uncertainty. Then we develop a genetic algorithm and tune its parameters to solve the models. We investigate the efficiency of proposed GA. Results were relatively good.... 

Dams are one of the vital infrastructures of the country and their correct use can have a significant impact on reducing costs and increasing their productivity. Due to the fact that dams are mainly large structures with a large number of components and with many complications of operation and maintenance, their operation and maintenance require spending a lot of money. On the other hand, the depth and volume of water behind the dams and the entanglement of the connection between the dams and the surrounding environment make the operation and maintenance of dams face many risks. The use of new technologies that can reduce the costs and risks of operating and maintaining dams can greatly help...