Sharif Digital Repository

In this study the modeling of Bushehr power plant containment is considered. In Bushehr atomic power plant, which has a unique design, the containment is similar to PWR power plants with a metal sphere, but the installed reactor is a VVER-1000. After a full study on the containment and its systems, the required date for modeling is gathered and afterwards, the engineering handbook is prepared for MELCOR input code and then the modeling and size classification of the containment is done in 4 different ways, including the control volumes of 1, 9, 23 and 30 and then the temperature, pressure and density of hydrogen is examined. The result of studying control volume sensitivity reveals that 23... 

Motion simulators have been highly sought after by the growth of the aerospace industry. In the meantime, the Stewart mechanism, or the so-called Hexapads, is a robot that, in addition to being used in machining tools, is mainly used to simulate the flight. The robot is considering the project to test parts and equipment installed in marine vessels under sea movements and waves. Therefore, according to information obtained through real case studies, the purpose of this project is to design and implement a hexapad controller and user interface for samples weighing up to 2 tons which can handle linear accelerations up to 1 g, rotary accelerations up to 200 º / s2 performs at a frequency... 

In this paper we empirically explore the bank lending channel and firm borrowing channel in Iran. Using the Embezzlement Scandal of 2011 as an instrumental variable for change in banks’ lending behavior, we identify the effect of credit constraints on borrowers’ performance. We use the firm-bank level data of short term loans from 2007- 2014 to maintain the goal. Results show that the banks’ lending behavior changes as a result of embezzlement shock and the borrowers’ performance get affected respectively. We show that the troubled banks reduce their lending by about 2.35 percent as compared to non-troubled ones. The results suggest that 10 percent decrease in loan supply, reduces the firms’... 

Although digital computers have been developed enormously in recent years, analog computing is still of great importance in some specialized application. There are basically two different methods to perform analog computing: metasurface approach (MS) and Green’s function (GF) method. In this contribution, we have focused our attention to the second method. In this approach, the associated Green’s function of the operator of choice is directly performed using a multilayered slab. Despite the applicability of this method, there are two major drawbacks regarding it. The first one is that it is only feasible to perform operators whose Green’s functions have an odd symmetry in the spatial Fourier... 

Design of thick-walled spherical and cylindrical vessels as fluids containers of high gradient thermal loading is a challenging issue. Using these tanks in high pressure and temperature gradient, particularly in chemical industries, needs to use new methods in design. Elasto-Plastic solution for thick-walled hollow spherical and cylindrical tanks made of FG materials subjected to internal pressure and temperature loading is presented. The power law modeling is used for through-the-thickness variation of mechanical properties. This method is using the new advanced materials with high pressure and thermal strength in fabricating these vessels. One of these materials is functionally graded (FG)... 

This research presents scheduling of several different projects in supply chain environment which activities of these projects are performed by some contractor companies. A new practical model for solving project scheduling problem in supply chain environment is present. Multi renewable resource presents in the model of research. The research proves that the model is NP-Hard. A genetic algorithm and a simulated annealing algorithm are proposed for solving the model. The parameters of genetic algorithm such as the number of steps, the number of mutation in each step, the number of crossover in each step, the number of generation phase and also the parameters of simulated annealing algorithm... 

Circular polarization (CP) is one of the common polarization types used in wireless systems for frequency identification (RFID), global positioning (GPS) and wireless local area networks (WLAN), since it can provide greater flexibility in orientation angle between transmitter and receiver, and better mobility and weather penetration than the linearly polarized antennas. Magnetic permeability in ferrites can be tuned by external magnetic field ; So ferrites can be good candidates for new reconfigurable CP antenna technology. In this project, we will consider circularly polarized slot antenna with a wide axial ratio beamwidth that consists of a normally magnetized ferrite substrate mounted... 

In urban rail transport systems such as subway, Trains are constantly accelerate and brake, so the braking system is of great importance in energy consumption and constitute about 30 to 40 percent of total energy consumption trains, thus retrieval braking energy will lead to significant savings in urban rail transport systems. In this paper, in the beginning, different storage equipments for storage braking energy have been studied and compared and finally Supercapacitors due to technical and economic features have been selected for the storge of equipment. These systems can be implemented in both stationary and onboard. For precise evaluation and select the appropriate storage system, by... 

Now a days, the ability of measuring the mechanical properties of the living cells in in experiments has been increased. Experiments shows that the stem cells could alter their faith in different mechanical situations, but an integrated model about this phenomenon in literature has not been introduced yet. In this research thesis s minimal cell model (MMC) is developed to capture the behavior of the cells on substrates with varying mechanical properties and morphologies, MMC consists of large scale models for outer membrane of the cell and nuclear envelope, cytoplasmic area, chromatin fibers and Extra cellular matrix. Each component of the MMC will be placed in an integrated software to... 

Due to the expanding trend of using induction furnaces in Iran, the production of sponge iron at a smaller scale by Midrex method has become important. Since induction furnaces cannot benefit from the oxygen blower and foam slag like arc furnaces, the induction furnace charge should be of a higher quality. In addition, as the oxidation conditions in induction furnace are higher in comparison to arc furnaces, re-oxidation control of the induction furnace is essential. Making briquettes is one of the processes, which reduces re-oxidation during melting and since the briquette remains floated on the melt until complete melting, the lower level of briquette's contact with ambient atmosphere and... 

Due to population growth, the demand for water supply has increased. This need has drawn attention to the use of consumed and treatable water resources. Organic pollutants are a key source of water pollution. On the other hand, petrochemical oil pollution and frequent oil accidents during oil production or maritime transport have become one of the environmental problems.There are different methods for water and oil separation and water purification that in the present project, selective separation can be achieved by using hydrophobic materials and surface roughness and creating surfaces with two properties: superhydrophobic and ultra-oil friendly. This method is also very effective, cheap... 

Based on fog computing paradigm, new applications have become feasible through the use of hardware capabilities of smart phones. Many of these applications require a vast amount of computing and real-time execution should be guaranteed. Based on fog computing, in order to solve these problems in is necessary to offload heavy computing to servers with adequate hardware capabilities. On the other side, the offloading process causes time overhead and endangers the real-timeliness of the application. Also, because of the limited battery capacity of the handheld devices, energy consumption is very important and should be minimized.The usual proposed solution for this problem is to refactor the... 

Investors highly value the ability to predict the behavior of the capital market. Over time, various methods have been introduced to forecast the future of this market and anticipate its movements. A novel approach to achieving this is by developing data-driven decision support systems that can assist investors in making informed trading decisions. The opinions of experts play a crucial role in shaping people's perception of the market, which ultimately affects its final behavior. In this study, we have created a decision support system that can help investors by considering the complexities and meaningful relationships between different aspects of the problem. We have developed frameworks... 

Mobile phones as new addition to information and communication technologies have created new ways to help learners in the process of foreign language learning in general and vocabulary learning in particular. Due to the importance of academic vocabularies for university students, this study set out to investigate the effectiveness of SMS on Iranian university students’ academic vocabulary learning and retention and to explore their attitudes towards SMS vocabulary learning. To this end, 52 university freshman students at upper intermediate proficiency level were chosen to take part in this study. Before the study in order to assess the participants’ vocabulary knowledge, a... 

In this study, the pervaporation method was used for desulfurization of gasoline. Thiophene was used as a sulfur agent and n-heptane as a representative of hydrocarbon compounds in gasoline. The composite membranes of the active PDMS layer containing the UiO-66 metal-organic framework nanoparticles are based on porous membrane PVDF. The effect of adding PVP polymer on the porosity of the PVDF membrane has been investigated. Scanning electron microscopy (SEM), Fourier transform infrared spectrum (FTIR) and X-ray diffraction (XRD) have been used to characterize nanoparticles and synthesized membranes. The effect of adding nanoparticles on the membrane performance and its sowelling effect in... 

In its most general manner, it is possible to express equations representing the change of state variables in space and time based on three-dimensional geometry and proceed to solve this set of equations numerically. However, this approach leads to an exponential increase in computational load and a reduction in real-time performance. The use of this approach becomes necessary when access to high computational power is readily available or when a high real-time factor is not required. By employing the hybrid systems approach, which has gained popularity in the past decade, it is possible to reduce the computational load and increase the real-time factor in the simulation of the dynamic... 

This research evaluates reliability analysis on the problem of a curved beam vibration in the horizontal plane with the aim of investigating the effect of the uncertainty of the parameters of the problem on the dynamic response of the curved beam under the excitation of the moving oscillator. Curved beams are widely used in various engineering applications such as arched bridges, railway tracks and amusement park structures. However, there have been very few studies on curved beams under the stimulation caused by moving mass. Modelling the moving object as a moving oscillator, which is one of the more advanced and complete modelling of the passing vehicle, along with analyzing the... 

High demand and price and restricted availability of Platinum Group Metals (PGMs) have made platinum recovery a major field of study for researchers and industries. Various methods have been introduced for this purpose. Ion exchange, leaching and liquid-liquid extraction (LLE) are just a few examples. Nowadays Solvent Extraction (SX) is one of the most challenging areas of study for platinum recovery from spent catalysts due to its simplicity and optimum cost. In this study, the commercial spent catalyst’s platinum was dissolved in aqua-regia after XRF analysis. Then it was extracted by the organic material Trioctylphosphineoxide diluted in toluene in the presence of Alkaline metal salts.... 

There are a lot of ways to measure the soil compaction but all of them have some deficiencies like low precision, soil destructive, time consuming and etc. The usual ways to measure the compaction in Iran are so traditonal and have the above problems. To solve these problems, modern ways like intelligent compaction is recomonded to decrease the time and cost of compaction. The observor can also control the compaction of all the soil point to prevent any offenses by making the network between the rollers.In new methods the soil compaction is calculated by measuring the roller vibratory and usage of fourier transform from the drum response . To compact the soil more precisely and more quickly,... 

The competition for staying in the business world has intensified today with the rise of open-source and commercial software. As long as a software is tailor-made to suit the needs of users, it is so-called alive and can stay in the competition. So the maintenance phase is necessary to make changes to the software to meet the needs of users. To reduce costs associated with this phase, it is necessary to avoid software bugs. One way to avoid software bugs is to use peer code review. Peer code review has been recognized as one of the best software engineering principles of the last 35 years. This principle helps maintain the quality of the code due to changes made to parts of the code that...