Sharif Digital Repository

Artificial periodic mediums such as metamaterials or photonic crystals have been intensively studied in recent years due to their unique characteristics and the ability to control their effective electromagnetic parameters. Developing accurate methods for the extraction of these parameters is highly desirable, given the potential application of artificial materials in optical and microwave devices. In this thesis a new method is presented for computing the effective bulk and surface parameters of three-dimensional artificial periodic materials. The effective, bulk permeability and permittivity tensors are shown to be directly related to the eigenvectors of the generalized transfer matrix of... 

In this research, a method based on the modified Enskog theory (MET) and some equations of state has been used to calculate the transport properties of some dense fluids. The main limitation to using the MET is the lack of experimental data for the co-volume, b0, that are substituted from the hard sphere (HS) theory, and the zero density transport properties that are substituted from the kinetic theory of gases for the HS in the MET expression, because of the fact that dense fluids behave more and less like a HS fluid. So a quadratic expression for both ηY/(√T ρ) and λY/(ρ√T) (C_(V,m)+ (9/4)R) in terms of Y at high densities (ρ > ρc) for each isotherm is expected, where Y = (T (∂p/∂T))/ρRT... 

In this study, membrane distillation process was used for treatment of high salinity waters. The focus of this study is to simulate and build a setup of membrane distillation process. Since the membrane distillation process is based on the driving force of the temperature difference, the required temperature is provided by both the use of heaters and the use of solar energy. To increase the feed temperature by solar energy, a black polymer coating on the main membrane is used. The main membrane used in this process is PVDF polymer and the polymer coated on the surface is the PAN polymer. After simulating and constructing the laboratory setup, the influence of a variety of parameters on the... 

The Delta parallel robot is used extensively in many industries, including packaging, because of its superior speed and precision. In this project a Delta robot was designed and then controlled specifically for use in the production line of a plastic container factory. In order to optimally design the robot, a number of desirable fitness functions were defined thus: minimizing the dimensions of the robot for a specific desired workspace, minimzing the effect of the robot’s weight on its actuators and satisfying the demands of the “Design for Control” approach. Design for control means considering the complexity of controlling a system while designinig it. Therefore the remaining fitness...