Sharif Digital Repository

One of the main arguments between scientific realists and scientific anti-realists is about observability. As a prominent anti-realist, van Fraassen and his theory of constructive empiricism and his views on observability and the use of scientific instruments, have been the subject of many debates. He believes that observation is the sole path to knowledge and observation is only possible through unaided human eye, so seeing through scientific instruments like microscopes does not count as observation, therefore the information gained from these procedures are not necessarily true.This thesis not only examines van Fraassen’s outlooks on the matter, but also examines his opponents’ view and... 

Micro-robotics is one of the currently emerging technologies which has attracted attentions for its probable applications in different fields including biotechnology, diagnosis and treatment in medical engineering as well as general studies in micro-scale science and engineering. Magnetic micro-robotics is considered as the most promising group, primarily due to the biocompatibility of magnetic fields and advances in electronic circuits to produce and control such fields. One critical point in utilizing these robots is their high density in comparison with the working fluid and their tendency to sink. In this thesis, a method to fabricate buoyant magnetic robots has been proposed based on... 

Nitrogen compounds are becoming increasingly important in wastewater management, because of the many effects that nitrogenous material can have on the environment that need nitrogen removal. In this study, the performance of a submerged fixed bed reactor in nitrogen removal, constructed two anoxic and aerobic sections under Modified Ludzack-Ettinger process was investigated. Laboratory experiments were conducted at a constant COD concentration of 350 mg/lit, hydraulic retention times of 8, 12 and 18 hours and influent ammonia loading rate between 0.128 and 0.955 g NH3/m2.day. Nitrogen removal efficiency was obtained between 80.4 and 97.3%, and COD removal efficiency was achieved between 88.9... 

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... 

Let C(S) and C(T) denote the sup-normed Banach spaces of real or complex-valued continuous functions on the compact Hausdorff spaces S and T, respectively. A linear map H:C(T)→C(S) is called separating if, for x,y∈C(T), xy≡0 implies HxHy≡0. In the second chapter of this thesis, we will show that any continuous separating map is a continuous multiple of a composition map. Moreover, it will be proved that any linear separating isomorphism of C(T) onto C(S) is continuous. We will also define separating and biseparating maps on the rings of continuous functions equipped with the compact-open topology. In addition, vector-valued separating maps will be investigated. For example, assume that C(T)... 

In this dissertation, transportation networks with two classes of vehicles, including conventional vehicles and autonomous vehicles, have been studied. Four problems, including traffic assignment problem with two classes, congestion pricing problem for conventional vehicles, network design problem for autonomous vehicles, and simultaneous congestion pricing and network design problem, have been modeled and algorithms to solve them are presented. In this study, a dynamic penalty function algorithm is used to solve the congestion pricing problem, and a heuristic algorithm is used to solve the network design problem. Besides, the two-class traffic assignment problem is solved using the... 

Three-dimensional (3D) computational fluid dynamics (CFD) was used in this study to investigate single and multi phase flow behavior related to three stages of ESP pump. Compared to experimental measurements, the numerical prediction for single phase flow of water is matched very well. Furthermore, the effects of viscosity and pump rotational speed for oil were investigated and the results show that by increasing oil viscosity and decreasing rotational speed, the pump head and efficiency reduced. ESP performance under two phase oil-methane flow and the effect of oil viscosity, rotational speed, intake pressure, gas bubble diameter, oil rate and gas volume fraction were studied. ESP boosting... 

Distribution power systems are undergoing a fundamental transition with the introduction of microgrids (MGs) and proliferation of renewable energy sources inspired mainly by privacy and environmental concerns. In this regard, energy management methods employed by utilities should take into account the intermittent nature of RESs power production while coping with the independent operation of MGs. Transactive energy (TE) is an emerging concept which utilizes economic-based mechanisms to facilitate the dynamic and decentralized management of active agents of the system. However, the energy transactions between transactive agents could have adverse impacts on the technical aspect of the system...