Sharif Digital Repository

The continuous rise in electricity demand and the ever growing power generation in different power networks over the world have caused the short circuit level in the power systems to exceed the operational rating of the installed power devices (including cables, circuit breakers and buses). Replacing these devices with new higher rating devices is an expensive solution. From this point of view, utilizing fault current limiters is an economical solution. Superconducting fault current limiters form an efficient category of current limiters. This type is expected to be studied and used widely in future due to their advantages. In this thesis, the first chapter reviews the superconductivity... 

The project aims to design and build a device that is capable of manipulation and control of micro-scale objects in dry and fluid medium. Among all the micro-manipulation methods, the use of magnetic fields has many applications. Because it has the ability to work without direct contact and also within a specified range for living tissue, is safe. To achieve this goal,manipulation systems ever made, were studied. Then, by presenting a conceptual design and the use of appropriate dynamic models for describing the behavior of micro-robot, the system performance was simulated. After this stage, The detailed design of the closed-loop system which must controls the position of the micro-robot... 

Biopotential sensors are used in a wide range of biomedical applications. For example, measuring electric potentials on the surface of living tissues in electroencephalography (EEG), electromyography (EMG), and electrocardiography (ECG) systems in which the brain, muscle, and heart activities respectively are measured over time. Moreover, these electrodes are used in measuring the pH of different materials and also in receiving and recording the electric field changes of the environment. The major purpose of biopotential electrodes is to act as a transducer between the ionic transport of the tissue and the electron flow in the electrode. Such a transduction takes place due to an oxidation or... 

Perovskite solar cells, with high efficiency operation, have been candidated as a cost-effective and environmentally friendly technology. Despite the great progress, there are some primarily issues remained regarding to the perovskite film and its fabrication methods. A very common perovskite cell structure is FTO/TiO2/CH3NH3PbI3/Spiro-OMeTAD/Au. Although, this structure has some advantages, lack of full surface coverage of perovskite film leads researchers to put much effort on finding other constructions. This surface inhomogeneity reduces the amount of light absorption and therefore efficiency. One way to produce a complete and uniform film is applying mixed-halide composition; such as... 

Cancer is one of the deadliest diseases of the modern era and accounts for 13% of all deaths in humans. Most cancers and lesions in the human body are related to soft tissue. Many soft-tissue cancers and lesions occur in sensitive areas of the body, such as the brain, pituitary, and intestine. The pituitary gland is located in the human head and near the optic nerves. Surgery in a typical way can result in risks such as heat loss of the optic nerve or injuries to healthy tissues due to the sharpness of the surgery tool. One of the alternatives to conventional surgery is water jet surgery. This method minimizes the risks of human error. In the present study, a water jet machine was designed... 

The primary purpose of the present thesis is to provide the feasibility of experimental determination of Counterflow flames dynamic response to acoustic excitations. Following this cause, an excitable counterflow burner test platform was designed, fabricated, implemented, and finally validated. The rich scientific literature associated with counterflow burners, the simple structure of the flame, conceivability of numerical simulation analysis in one, two, or three dimensions, the simplicity of structure among fundamental flames which are correspondingly in resemblance with industrial flames and finally the ability of universalization of scientific result to industrial flames are the reasons...