Sharif Digital Repository

In the presented dissertation an analytical model is developed for the air gap flux density and the cogging torque in the axial flux surface-mounted PM machines. The slotting effect is taken into account in the magnetic flux distribution.The model is derived from solving the 2D Poisson' equation in the slotted air gap. To simplify the solution process, the concept of the uniqueness theorem is used to replace the slotted air gap by a slotless one and some surface current distribution. In addition, the separation of variables method is applied to the analytical solution of the Poisson equation. However, the proposed 2D analytical model is developed for the quasi 3D model by the well-known... 

Developing and progressing excavation technology, and distillation and petroleum technology as fuel cause chemical and hydrocarbonic materials have been given an important role in human life. Having petroleum expanded, its effect in countries’ economics has been highlighted and found a substantial role in countries’ development. Iran, considering 11% extractable petroleum reserves which is equivalent to 138 billion barrel, is known as an oil rich country. The petroleum has an eminent role in country’s economics and is the main country’s income source and the most important exports. With regard to the high technology needed for petroleum exploration and purification, Iran requires foreign... 

Knowing the trip information such as paths that travelers prefer to choose is useful for practice in developing certain transportation planning step. There are different methods such as using GPS and conducting survey for volunteer travelers in order to understand actual paths. Obviously, all of these methods have some deficiencies. This research suggests and examines a method for estimating travelers’ path by using cell phone data. The main advantage of using these kinds of data is enabling the process of collecting information without any active interference of the users. A big data set consisting of 300,000 cell phone users’ information in the city of Shiraz is studied to achieve this... 

Energy production from fossil fuels such as oil and gas is one of the non-renewable energies, which causes many environmental problems such as global warming and environmental pollution. The existence of these problems has led to agreements such as the Glasgow Environmental Agreement, which obligates governments to apply methods to reduce the production of greenhouse gases, which include reducing the consumption of fossil fuels and increasing the use of renewable energy. Sea wave energy is one of the renewable energies that can be used to generate electricity. In the seas of Iran, including the Caspian Sea, Persian Gulf and Oman, there are sources of wave energy that can be used and are... 

Today's interest growth to the underwater explorations and navigations demands to design appropriate underwater communication methods and systems is strongly felt. Although radio frequencies which are widely used in free space communications, they cannot be a decent candidate for underwater wireless communications, due to their sever attenuation in water environment. On the other hand, underwater acoustic communications has been widely studied and implemented in past decades, because of little attenuation in comparison with other means of communications in water environment. However, acoustic communications suffer from limited bandwidth, low propagation speed, and low security in compared... 

It is the goal of this thesis to develop an analytical model for the hydro-mechanical deep drawing (HDD) process of an axisymmetric sheet metal with the fixed gap method to evaluate the effects of some assumptions such as: proportional loading, plane stress, and constant thickness conditions. The effect of parameters on the HDD process is also studied. The main model is developed with considering the normal stress and part thickness change, non-proportional loading, bending and unbending effects at the top of the cup wall. The interrelationships between geometrical and mechanical variables are obtained in the finite difference form based on the incremental strain theory, thereby being solved... 

Advances in IC fabrication makes possible have systems on chips. In this thesis we have designed and fabricated a digitally controlled bias chip for a transceiver which can be programmed by its digital interface. In this thesis, briefly we review basics of voltage regulators and methods for controlling them. Then we introduce high voltage 0.18um CMOS technology. In this thesis, we describe the requirements of a specific transceiver and present a system to overcome these requirements. This system has positive, negative and internal regulators, a five-bit analog to digital converter, temperature sensors, power amplifier controller and digital serial interface. In this thesis, we present a... 

The use of fluorophores in metallic and non-metallic analysis, have received great attention for chemical sensing due to the high sensitivity and selectivity. Fluorophores through participating in emission mechanisms, interact with analyte and the emission intensity changes, which leads to determination of analyte concentration. These mechanisms are included fluorescence resonance energy transfer and fluorescence emission quenching. In the first part of this thesis, a highly sensitive probe for detection of copper ions was developed based on fluorescence resonance energy transfer due to the plasmonic peak of citrate capped gold nanoparticles and emission peak of FITC. Quenched emission of... 

The aim of the current research is to study the process of making a solidstate nanopore by molding from PDMS polymer and to make a laboratory sample of a solidstate nanopore manufacturing device using this method. Solid-state nanopores are used to control ion transport in microfluidic channels,lab-on-a-chip detection to study nucleic acids and proteins, desalination, nanofluidic transistors,single-cell sensing tools, and particle classification. In general, the smaller the nanopore, the shorter the length and the higher the mechanical stability, the better the performance. In this research, chips have been made on which there is a blade with a sharpness of 10 nanometers and a height of 10...