Sharif Digital Repository

Although the popularity of Darrieus-type vertical axis wind turbines is growing for small-scale electricity generation, these turbines have severe challenges in self-starting. This research study use the plasma actuator flow control method to solve the self-starting problem besides enhancing the turbine performance. The Darrieus turbine is numerically investigated using a pressure-based finite volume method to solve the unsteady Reynolds-averaged Navier-Stokes (URANS). Simulation of the blade rotation is performed using the sliding mesh technique accompanied by the turbine equation of motion to enable the blade rotational degree of freedom. The results in plasma off condition show that the... 

With the development of electrical engineering and the electrical industry, the use of copper and its alloys has grown tremendously. On the other hand, with development and modern industry, it will be difficult to meet the requirements such as high performance, cost reduction and weight reduction of the structure if only one metal material is used in the production of the desired component or structure. Aluminum can be used in combination with copper because of its properties such as high thermal and electrical conductivity. Al/Cu bonding is used in industries such as microelectronics, automobiles and batteries. This study has investigated parametrically the feasibility of uneven bonding of... 

The Dynamic Maximal Covering Location Problem (DMCLP), is one of the classes of Facility Location Problem (FLP) with a wide raneg of applications in real-life situations. In order to solve this problem, this research presents a sufficient greedy heuristic algorithm, which is capable of solving the DMCLP in large scales of 2500 demand nodes and potential facilities of 200 in 5 periods in a negligible computation time in comparison to those with exact algorithms such as branch and cut. Furthermore, in this research DMCLP is also modified to reach reach a more realistic model. In this new model, a cost behaviour is defined according to the number of facilities located. Subsequently, the new... 

The emergence of Autonomous Vehicles (AVs) provides the opportunities to ameliorate traffic congestion while increasing safety. AVs, using the vehicle to vehicle and vehicle to infrastructure communication, can gather and infer the information of adjacent vehicles and traffic flow. The objective of this article is to develop a cooperative control method to manipulate AVs longitudinal and lateral movements in order to enhance macroscopic features of the mixed traffic flows. In this paper, we propose a potential function to control longitudinal movement of AVs considering their physical constraints. The developed controller provides an optimal, collision-free car following by minimizing the... 

In recent years, requirement engineering and goal modeling have gained more attention among different organisations. Therefore, different methods have been designed to discover stakeholders’ requirements and translate them into process and organizational goals. Various goal models have been introduced to represent these goals and their relations towards each other. Still, these methods are manual representations of different process scenarios and do not relate to the actual behavior. In 2014, Map Miner Method (MMM) was introduced to discover intentional process models from event logs. MMM uses Hidden Markov Model (HMM) as a means to represent the process as a map model of strategies and... 

Recommending routes to city taxis in order to improve their performance in finding passengers can reduce traffic, pollution and waiting time for passengers, as well as this, increasing the efficiency of taxis can increase their income. In this study, by analyzing trajectory data obtained from 536 taxis in San Francisco over a period of one month, we generated networks of cells, each of which has time-dependent characteristics such as the probability of finding a passenger, the capacity of each cell, or the amount of demand exists is in the cell and the average speed of passing through that cell. also, the connections between these cells in order to make more use of the experiences of taxi... 

The purpose of the present study is to develop neural network estimation method for hybrid or panel data which have a combination of two cross-sectional and time series structures and because of the features of both structures, their use in different sciences offers many advantages; and the analytical methods for this data structure are also different from other one-dimensional structures, so different and specific regression models are presented for this data structure. However, in the artificial neural network method, modeling the development for this data structure is neglected, so in the present study, using the concepts of panel regression methods and their application to the... 

Inlet performance is an important field in aerodynamic design of aerial vehicle engines. This study has been focused on nummerical investigation of inlet performance. For this purpose, a density based finite volume CFD code has been developed to solve supersonic axisymmetric flow in a mixed compression inlet. A structured multi-block grid and an explicit time discritization of Reynolds averaged Navier-Stokes (RANS) equations have been used. Furthermore, both Roe’s approximated Riemann solver and advection upwind splitting method (AUSM) have been utilized for computing inviscid flux vectors. Also, the monotone upstream centered schemes for conservation laws (MUSCL) extrapolation with Van... 

The problem of Origination of The Universe is one of the most important issues in the history of philosophy whether in western edition or in Islamic thought. The most problematic aspect of the Origination is Temporal Origination. From about 30 years ago as a result of the works of a famous American philosopher William Lane Craig, the debate between temporality and Eternity of the Universe became a fresh topic in western philosophy. In this research we want to survey the philosophical arguments for and against the temporality of the Universe based on the views of: W.L.Craig, Q.Smith and Allamah S.M.H Al-Tabatabaie.
 

This thesisconsiders new fundamental approaches to yield heterogeneous catalysts in to three sections. The first section described the immobilization of the molybdenum-Schiff base complexes in pores of SBA-15 in two different methodologies depending on the actual structure of the complexes., (i) stepwise formation of the complex by initial covalent anchoring of one of the components and consecutive solid phase synthesis consisting of the condensation of the other components of the salen complex (iii) one-step complex immobilization by covalent binding through the ligand.Based on the first methodology, we report the preparation of ordered mesoporous silica SBA-15 containing a molybdenum...