Sharif Digital Repository

In this thesis, we study the fate and consequences of the existence of edges or domain walls with non-zero thickness and how the properties of edge modes arising from symmetry-protected topological (SPT) phases and consequently the bulk dynamics of these phases changes due to this thickness. This general study is specifically examined in the context of anomalous quantum Hall effect (QAHE) systems as an example of these topological phases. Symmetry-protected topological phases are an important category of gapped material topological phases that, although lacking long-range order, exhibit non-trivial properties in the presence of boundaries. These non-trivial properties arise due to the... 

Thermal energy and water in flue gases varies with the type of fuel and thermal conversion system. Flue gas temperature is maintained in the range of 140 (℃) to 200 (℃) and it is subject to the sulfur content of the fuel. Vapor content of the flue gas is in the range of 10%_20% of volumetric flow. Considerable part of vapor may be recovered which can be used as cooling water make up. There are various means and methods for water capture and heat recovery which includes shell-tube heat exchanger among others. Selection of appropriate material and heat exchanger is conditioned by corrosion, temperature of flue gas and it’s economic feasibility. Identification of an optimal design of... 

The goal of this research is design and manufacturing of a device for fatigue test and 3D crack propagation in spur gear roots. Clearly it should be able to test gear in oscillated bending load and control the amplitude and period of loading. Designed setup in this project using a electro hydraulic actuator can do it up to 50 KN and 10 Hz in amplitude and frequency and a PLC controls it during the test time. System can load gears symmetric or anti symmetric and simulate the effect of shaft misalignments, bearing damage and gear production tolerances on the gear loading. System completely designed, built and tested during this project and using experimental data, its performance was... 

In his book “Groundwork for the Metaphysic of Morals ”, Kant tries to pesent a formula for the supreme pinciple of morality. He ends up introducing three formulae that he thinks are all the same and just pesenting one formula In three different ways. After publishing this book, many criticisms were levelled against both his way of argument and the efficacy of his proposed formulae. In this enquiry, by focusing on the first two chapters of Kant’s book, and by considering the universal law formula and the humanity formula, we try to answer these criticisms. In the way, we make use of the new reading of Kant’s view- the critical reading- proposed by Samuel Kerstein, according to which Kant’s... 

In geotechnical engineering, collapsible soils as a part of problematic soils has an extreme importance since as a mutual effects of applying load and increasing their water content, Soil’s inter-particle forces become weak, and therefore, the soil experiences sudden large volumetric change known as collapse. Foundations built on these soils might experience sudden, large settlement. Collapsible soils exist in almost all continents, and many damages are reported due to the collapse phenomenon of these soils.
Due to the importance of this issue, and lack of comprehensive studies related to the volumetric and shear behavior of these soils, in this study, triaxial wetting test are performed... 

In nature, tidal currents are visible in gorges and in saltwater and freshwater collisions. In the study of behavior of different types of flow, it is usually assumed that the pressure is hydrostatic and the equations are solved based on this assumption. In the Approach Controlled regime observed during the double layer in 1993, the modeling performed using the equations derived from this assumption did not fit the results of the experiments. This demonstrates the inability of the hydrostatic pressure assumption to solve this particular regime. Hence, the equations were written on the basis of non-hydrostatic pressure and then the observed results were in accordance with the results of the... 

In this thesis one of the sensorless methods which exploits the existing anisotropies of the rotor is utilized to estimate rotor position. In order to implement this method, first a high frequency voltage is injected in a specific, time-varying direction and then the corresponding current response would be observed in order to estimate the rotor saliency position. The estimation of rotor position would be more precise as the magnetic anisotropy due to rotor saliency increases and as a result the effect of noise and different disturbances in estimation of rotor position would be decresed. The effect of stator resistence is one of these disturbances which is usually neglected as a result of... 

This study investigated the effect of Robot Assisted Language Learning (RALL) on the vocabulary learning and retention as well as anxiety and attitude of Iranian English as Foreign Language (EFL) junior high school students in Tehran-Iran. After taking a vocabulary pretest, 46 beginner level female students at the age of 12, studying in their first year of junior-high participated in two groups of RALL (30 students) and non-RALL (16 students) in this study. The textbook used was the English book (Prospect-1) devised by the Iranian Ministry of Education for 7th graders, and the vocabulary taught and tested (pretest and posttest) were taken from this book. Moreover, the treatment given by a... 

Considering uncertainty is of great importance in the design of controllers for dynamical systems because the existence of uncertainty is inevitable in the modeling of almost all real-world systems. There are numerous methods and strategies for dealing with the control of uncertain systems in control systems theory including adaptive and robust approaches. The former one is more suitable for cases in which the information about uncertainty is very poor compared to robust techniques that are applicable in the cases more data is available about uncertainty. For instance, where there is no data about the direction in the actuator model, adaptive control methods are the only applicable choices....