Sharif Digital Repository

Nowadays, cooling towers are widely used in power plants, refineries, petrochemicals and ventilation industries, but the water consumption of these towers is high and because of water crisis in Middle East and Iran, it is necessary to devise in order to reduce the water consumption of these towers. In this study separated hybrid cooling tower are used to investigate the water consumption at power plants. The rigorous Poppe method are used in order to estimate the exact amount of water loss due to evaporation in wet cooling towers. First, the effect of ambient condition, wet cooling tower cells and dry cooling tower size on the performance of hybrid cooling tower are investigated, then the... 

Controlled islanding, also known as system splitting, can effectively prevent blackouts of power system by separating it into two or more islands. To make each island reach steady state point by available measures, each island must be observable. This paper proposes a new modified three phase method to find proper splitting strategy, considering observability as a new constraint, to minimize effect of system splitting on network observability. Some techniques about strategy searching are introduced to increase its speediness and related algorithms are described in detail in this thesis. The simulation results presented show efficiency of method in finding proper splitting strategies. In the... 

In recent years, investment in financial markets has seen exponential growth in the number of investors and the capital they have invested. Investors enter these markets with the goal of maximizing their transaction profits. Therefore, they are looking for a way to predict the future of the market. On the other hand, numerous factors influence stock prices and market trends, making the prediction of these markets a highly complex task. In recent years, with the remarkable advancement of artificial intelligence, analysts’ ability to predict stock trends has greatly improved. In this research, we attempt to predict stock trends using financial market concepts and machine learning models. To... 

The occurrence and development of scour hole around bridge pier are the main causes of bridge destruction. To predict manner, occurrence, development and final situation of scour hole around pier is the most important in the hydraulic design of bridges. A large number of studies have been performed to estimate the scour depth around piers at simplified laboratory conditions. The available equations from these studies do partly not present acceptable solutions. This issue is especially of great importance to the pile groups. For accurate determination of scour depth, it is required to get a better understanding of the flow and governing mechanism around pier. Although the flow pattern... 

Geothermal piles are elements with dual structural and thermal functions, playing a significant role in sustainable development by reducing costs, energy consumption, fossil fuel usage, and greenhouse gas emissions. These geostructures, integrated with ground source heat pumps, utilize renewable geothermal energy for building heating and cooling, transferring heat to or from the ground throughout the year, serving as an effective solution for environmental goals. Numerous studies have investigated the hydraulic, thermal, and mechanical behavior of geothermal piles under various boundary conditions and parameter changes. This research conducts a thermal-hydraulic finite element analysis using... 

SiCl4 catalyzed Michael addition reaction of aliphatic and aromatic amines with different α,β- unsaturated compounds and one-pot three component Mannich reaction under solvent-free condition were investigated. β-amino carbonyl compound were synthesized in high yield in short reaction time. Furthermore, in the Mannich reaction good yield and excellent stereoselectivity were observed. In addition, the synthesis of 2-substituted benzothiazoles from aromatic aldehydes and 2 aminothiophenol in moderate to excellent yields in water in the presence of PTSA catalyst (10 mol%). This method provides a simple and efficient protocol in terms of mild reaction conditions, clean reaction profiles, small... 

Properly adjusting the trim angle during the craft speed up will be extremely important in special cases as in sport competitions or military missions. In such applications, the goal of trim adjustment is to reach final speed in a minimum possible time which is an advantage to just passing the resistance hump. Present study tries to provide insight into how the concerned control variables such as angles of the drive system and trim tab of a planing craft should be changed during acceleration mode so as to minimize the time needed to reach the final speed. This is a time-optimal control problem. Optimal control theory has been used previously for the motion control of marine vessels in... 

The main methods have been used clinically for cancer treatment are included: surgery, chemotherapy, radiation therapy and hyperthermia. Hyperthermia (heat therapy) treatment method in which by raising the temperature of the tumor it removed. Magnetic hyperthermia is known as a kind of hyperthermia that have been represent appropriate results. In this study, using iron oxide nanoparticle coated with graphene for cancer treatment under a magnetic field of the laser. In the first stage, graphene oxide nanosheets and nanoparticles Magntayt are synthesized by chemical oxidation and co-precipitation, respectively. At the end, the nanoparticles on the substrate of graphene layer is obtained...