Sharif Digital Repository

Cardiovascular diseases are the leading cause of death all over the world, even more common than cancers. The first reason of mortality in Iran according to statistics is the occlusion of coronary arteries. Unfortunately almost one third of patients doesn’t have enough blood vessels to be used in the bypass surgery and need artificial vessels. These artificial blood vessels with small diameters (less than 6 mm) will fail quickly. As a result there is an increasing demand for tissue engineered blood vessels which are capable of enduring high blood pressures. An artificial blood vessel should mimic both structure and mechanical properties of the real one. Blood vessels have layered structures,... 

A lot of researchers have suggested that ostracism as a disruptive behavior, has been widespread among organizations and a lot of researches has been studied its consequences in recent years.This research studies ostracism’s consequences and proposes a theoretical model of organizational ostracism with affective commitment, intention to turnover and organizational dependability as one of affective commitment’s antecedents. This study has been done on 231 employees of three medium knowledge-based organizations to identify the effects of ostracism on employee’s turnover behavior. Results show that ostracism, due to its impact on the affective commitment of ostracized peoples, reduces this type... 

Tehran is the most populated area in Iran and is one of the most densely populated cities in the world where almost 40 percent of all days have been classified as unhealthy for sensitive groups. According to emission inventory of Tehran over than 85 percent of emission are due to different types of vehicles. And light duty vehicles share more than 80 percent all vehicles and are responsible for most of carbon monoxide and nitrogen oxides emitted in Tehran atmosphere. In this study real emission factor of Hybrid Synergy vehicles which just have been introduced to Tehran fleet were tested under real conditions of streets. Data produced in this research have been combined with previous... 

XY Model due to topological defects (or vortex) has topological phase transition. According Kosterlitz-Thouless (KT) theory, phase transition is from low-temperature bounded vortices to high-temperature free vortices. XY model is appropriate choice for description of superfluidity in 2d thin films of . KT theory predicts universal jump in mass density of 2d superfluid in phase transition point. It is confirmed experimentally by Bishop and Reppy. All critical behavior of XY model is described with 2d coulomb gas, vortices are topological charges of the gas. KT predict variance of topological charge should obey of the “surface law vs perimeter law”, similar to behavior of Wilson loop in ... 

One of the important issues in the philosophy of mind is the challange about the content of mental states, how the mind can refer to the world. To explain this special relationship that is not observed in the physical world, various mental models have been implemented, one of which is the connectionism model. Connectionist networks are based on the idea of biological neural networks, and the main concern of connectionism is modeling the brain and implementing human mind characteristics. The connectionist model was proposed by emphasizing the necessity of linking symbols with their original content and meaning. In this model, data representation is done in a holistic way and based on network... 

In this research, we explore a novel approach for controlling continuous-time chaotic systems with unknown equations and exclusively using one measurable state variable. In pursuit of this objective, the study unveils two efficient approaches: one tailored for autonomous systems and the other designed for systems with external excitation. In both approaches, our methodology centers on minimizing the conditional entropy which is derived based on the conditional probability distribution of the only observable state variable. Considering the numerical nature of entropy calculations in practical issues, we have employed the Poincare map to discretize the continuous-time system. In the following,... 

Airport saturation is one of the important issues which have always been of the specialists’ concern. One of the major applications of this subject is at the airport approach problems. While using current conventional approach procedures have many disadvantages regarding high fuel consumption and subsequent much environmental and noise pollution, the CDA concept which is one of the modern topics introduced in consequence of free flight theory, has less such disadvantages compared to conventional approach. Subject of this study is to investigate whether Procedural approach or CDA saturates an aiport sooner if the traffic flow increases. In this dissertation, using BADA database, CDA...