Sharif Digital Repository

Lake Urmia is the largest inner lake in Iran that has been dessicated continuously over the past two decades, and most of it has dried up. Urmia Lake basin is one of the country's agricultural and industrial pillars and has more than 5 million inhabitants. The conflict between people’s interests and the environmental ones besides increased demand for water harvesting has led to a reduction in water inflow to the lake. As the water resources management issues became more complex in last two decades with the entrance of political and socio-economical, the concept of water resources management has been promoted in the broader sense of water governance. The solution to the problem of Lake Urmia... 

Up to early seventies, Gas turbine combustor design was very time consuming and costly process including trial and errors through test rigs. Over the time analytical-experimental relationships take place as one of the key rules in the design processes. With the increasing power of computer calculations, computational fluid dynamics find its way in the procedure. Obtaining a deeper understanding of flow conditions and geometry inside the chamber, a great reduction in production time and cost of revisions to rigs and samples were achieved. Finding a precise prediction of polluting elements like NOx (less than 10 ppm) after many run hours and enormous computing resources, CFD methods must... 

Fed-batch fermentation is a valuable and cost-effective method for bio-based production of various products such as ethanol, which has various applications in various industries.In recent years, bioethanol production has been given special attention in many countries. For this reason, the mathematical modeling of production of these products is very important for their optimal and cost-effective production. Given the transient and dynamic nature of fermentation and its specific complexity, mathematical modeling of fed-batch bioreactors is difficult and complicated. In this research, an unstructured model was used to predict the production of ethanol from blackstrap sugar cane molasses based... 

Neural Networks have been applied to Language Modeling to solve a major problem that N-gram language models could not overcome: discreteness of the words. Generally, neural networks were successful in solving this problem and improved Language Modeling by reducing the perplexity of the models. Neural networks can find grammatical and semantic connections among the words using word embedding which maps each word to a low dimensional feature vector of real numbers. In this research, different kinds of neural network applied to Language Modeling has been reviewed. Also, it has been tried to reduce the perplexity of Persian language models on a 100-million scale data set using a single-layer... 

Although the moment frame can show deformable behavior against seismic loads, but its flexibility and low stiffness, especially in tall structures, cause the governance criterion to be designed. The use of eccentrically braced frames was able to solve the displacement problem to some extent, because it has the characteristics of both flexural frame systems and conccentric bracing. Different methods have been proposed to eliminate residual displacements in this type of system, one of which is the use of post tensioned cables. The aim of this study was to investigate the seismic behavior of a steel structure with a eccentrically braced frame system with post tension cable.The cables are anchor... 

In the present work, Barium Titanate nanoparticles were synthesized by a facile hydrothermal method at 180oC for 4 hours and their sintering behavior was studied. The characterization tests illustrated that the obtained powder was BaTiO3 single phase with excess Ti content from stoichiometric composition. The average particle size of about 50 nm and a narrow particle size distribution was noticed. SEM investigations showed that the samples sintered at temperatures less than 1250oC had plate-like grains. This behavior resulted from twin plates existed in the grains and facetted grain boundaries. At the temperatures more than 1250oC, the grains became polygonal due to the formation of trace...