Sharif Digital Repository

A large number of structures and substructures, such as piles, have damaged or even yielded the entire structure during seismic loading. The kinematic interaction of piles under seismic loading has been widely studied from analytical, experimental, and numerical perspectives. In numerical modeling, most existing literature relies on simplified approaches to describe the soil-pile interaction, which leads to the need for more reliable and comprehensive research. In this research, the seismic response of the soil-pile system was investigated through a fully nonlinear three-dimensional numerical analysis in the time domain using the FLAC3D program. This model simulates the dependence of soil... 

Ultrasound hyperthermia is a commonly used noninvasive approach to destroy cancer tumors. High Intensity Focused Ultrasound (HIFU) is a technique based on hyperthermia. It creates short and local elevations of temperature at a focus site within the tissue of interest. The main goal of HIFU is to maintain the temperature between 50 and 100 °C for a few seconds (typically less than 10 s), in order to cause tissue necrosis. In order to predict the effects of hyperthermia, accurate and effective modeling is needed. This study considers a 3D simulation of the hyperthermia based on HIFU method in the liver tissue. Temperature distribution and lesion volume changes, with a temperature of above... 

Using magnetic torquers as the sole actuator for attitude control of small satellite despite its benefits has a drawback that is lack of controllability. Mechanical torques can be created only perpendicular to the instantaneous magnetic field vector, thus at each time instant the satellite can be controlled only around two axes out of its three perpendicular axes.
Fortunately because of the satellite motion, the direction of uncontrollable axis changes by time, therefore the sufficient attitude control can be achieved along time. Almost all of the present magnetic attitude control methods need more than one orbital period to control and cause the attitude to converge to the desired... 

Structural defects such as cracks may be produced in structures and machineries under fatigue load operating conditions. The presence of crack can lead to catastrophic failures in certain conditions. The occurrence of cracks affects the dynamic and vibration behavior of the structure considerably. These vibrations can be used for identifying the cracks and appropriate actions can be taken to prevent more damage to the system. Therefore, in this thesis vibration analysis of a Timoshenko beam with a vertical and horizontal crack has been considered. A continuous model for vibration analysis of a beam with an open edge crack including the effects of shear deformation and rotary inertia has been... 

Computer-assisted language learning (CALL) has been the focus of investigation in the field of foreign language learning for many years. This study aimed to investigate the impact of learning through blogging on the students’ essay writing skill and attitude in the Iranian context. As an extension of the research conducted earlier by Lin (2015) 32 Sharif University of Technology students were selected as the participants of the study. To this end, the students were divided into two groups of experimental group and control group. Then, they were instructed in two different ways by using different teaching methodologies. The bloggers, experimental group students, did not receive any direct... 

Understanding many issues related to environmental geotechnics and soil sciences such as: instability and collapse of soil slopes, sinkholes, leakage from landfills and isolation of nuclear landfills, and optimization Agricultural processing depends on our knowledge of the behavior of unsaturated soils and their volume changes. To better understand the behavior of unsaturated soils, it is important to study the soil-water retention curve (SWRC) and the factors affecting it. These include factors such as porosity, grain size distribution, soil minerals, pore size distribution, and pore water chemistry, which affect soil-water retention curves and volume changes. Since the simultaneous effect... 

The conversion of CO2 gas into value-add chemicals known as solar fuel technology attracted much consideration from the beginning of the 21st century owing to the potential of this technology in solving the climate change and energy shortage issues. In the present study, a well-known photocatalyst, TiO2, was doped with Bismuth element and was subjected to Pt nanoparticles loading as a cocatalyst to boost the photocatalytic CO2 conversion. Pristine TiO2 and Bi-doped samples were prepared by sol gel method. Then, a facile photo-deposition method was employed to introduce Pt onto the surface of TiO2. Various characterization techniques including XRD, DRS, BET, PL, FTIR, FESEM and TEM, were used...