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abazarsa--fariba
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Experimental Study of the Behavior of a Semi-rigid Connection under Shear
, M.Sc. Thesis Sharif University of Technology ; Khonsari, Vahid (Supervisor)
Abstract
Recent studies show that the most efficient connections are those which have more flexibility and energy dissipation capacity in addition to their strength and stiffness. While their flexibility reduce the earthquake-induced forces, their energy dissipation capacity, by dissipating some of the energy at connections, can reduce the share of structural members of the total energy that has to be dissipated, hence increasing their chance to remain intact and undamaged during an earthquake. Since conventional connections, even semi-rigid ones, have great shear rigidity, there is not any article in the literature about shear behavior of beam-to-column connections. However, due the fact that the...
Fabrication and Optimization of Organic Inorganic Perovskite Solar Cells Using Vapor Phase Deposition
, Ph.D. Dissertation Sharif University of Technology ; Taghavinia, Nima (Supervisor) ; Tajabadi, Fariba (Supervisor)
Abstract
In this research, we focus on study and fabrication of organic inorganic solar cells. We use and optimize various methods such as one-step spin-coating, two-step sequential deposition and vapor-assisted solution process (VASP), to prepare high quality perovskite films. One-step deposition is simplest method for deposition of perovskite films. Although perovskite deposition by this method is very simple, the control of uniformity and surface film morphology is difficult. Chlorine inclusion, optimization of annealing conditions, and a sequential solution-based deposition method have been demonstrated to increase film coverage and uniformity. Hence, we use sequential deposition method for...
Response-only modal identification of structures using limited sensors
, Article Structural Control and Health Monitoring ; Volume 20, Issue 6 , 2013 , Pages 987-1006 ; 15452255 (ISSN) ; Ghahari, S. F ; Nateghi, F ; Taciroglu, E ; Sharif University of Technology
2013
Abstract
Herein, we propose a method based on the existing second-order blind identification of underdetermined mixtures technique for identifying the modal characteristics - namely, natural frequencies, damping ratio, and real-valued partial mode shapes of all contributing modes - of structures with a limited number of sensors from recorded free/ambient vibration data. In the second-order blind identification approach, second-order statistics of recorded signals are used to recover modal coordinates and mode shapes. Conventional versions of this approach require the number of sensors to be equal to or greater than the number of active modes. In the present study, we first employ a parallel factor...
Blind modal identification of non-classically damped systems from free or ambient vibration records
, Article Earthquake Spectra ; Volume 29, Issue 4 , 2013 , Pages 1137-1157 ; 87552930 (ISSN) ; Nateghi, F ; Ghahari, S. F ; Taciroglu, E ; Sharif University of Technology
2013
Abstract
A significant segment of system identification literature on civil structures is devoted to response-only identification, simply because lack of measurements of input excitations for civil structures is a fairly common scenario. In recent years, several researchers have successfully adapted a second-order blind identification (SOBI) technique-a method originally developed for "blind source separation" of audio signals-to response-only identification of mechanical and civil structures. However, this development had been confined to fully instrumented classically damped systems. While several approaches have been proposed recently for extending SOBI to non-classically damped systems, they all...
Investigation of Quantum States of Light (Generation and Utilization Their Special Properties) in Quantum Information Science and Precision Measurements
, M.Sc. Thesis Sharif University of Technology ; Karimipour, Vahid (Supervisor)
Abstract
Quantum entanglement and superposition are wonderful and mysterious phenomena of quantum mechanics. By means of quantum entanglement, two or more systems become partner in state of each other . As a result, measurements on each of these systems affect the status of other systems. Quantum superposition allows a system inhabits several of its possible quantum states simultaneously. These two features are applicable in many technologies in present age. Photons, as an quantum unit of light, are appropriate candidate for utilization these properties. Because they are robust to decoherence and for their preparation exist various methods. Hence, we interested to generation of quantum states of...
A Study on Action Selection Deficits in Schizophrenic Patients Using Computational Modeling in Reniforcement Learning Framework
, M.Sc. Thesis Sharif University of Technology ; Vosoughi Vahdat, Bijan (Supervisor) ; Bahrami, Fariba (Supervisor)
Abstract
Schizophrenia is a devastating disorder that steals the opportunity of having a normal life from the sufferers. Drugs used in treating this disorder usually target psychotic symptoms and do not affect negative symptoms effectively. One of the deficits falling into this category is the impaired reversal learning. These patients usually learn the rules but do not renounce them after the contingencies of reward have been reversed. To investigate the reasons of this impairment, first a hypothesis of how different parts of the brain communicate during reversal learning is proposed using the physiological evidence. Then considering the known relation between the actor-critic model of the...
Improvment of Perovskite Layer and Perovskite/Hole Transport Layer Interface to Inhance Perovskite Solar Cell Performance
, Ph.D. Dissertation Sharif University of Technology ; Taghavinia, Nima (Supervisor) ; Tajabadi, Fariba (Supervisor)
Abstract
The use of renewable energy sources has received much attention due to the increasing need for energy, limited energy resources and the pollution of fossil fuels. Among all types of solar energy conversion technology, photovoltaics has the highest technical potential and Iran’s geographical location is very suitable for benefiting from this energy. So, in this thesis, the fabrication and characterization of nanostructured solar cells based on organic-inorganic perovskites have been investigated. Many research goups have tried to increase the efficiency of perovskite solar cells. The efficiency of this kind of solar cells depends mainly on the light-absorbing layer (perovskite) and its...
Printable Carbon Electrode for Perovskite & Thin Film Solar Cells
, Ph.D. Dissertation Sharif University of Technology ; Taghavinia, Nima (Supervisor) ; Tajabadi, Fariba (Supervisor) ; Mohammadpour, Raheleh (Supervisor)
Abstract
Solar cells, as a part of photovoltaics (PV) industry, have a significant share in the renewable energy market. Perovskite solar cells (PSCs) and thin film solar cells (TFSCs) achieved 23% and 22% power conversion efficiencies (PCEs) respectively. However, the PV industry still faces challenges like “high manufacturing costs” and “stability”. Among the strategies to overcome these challenges are substitution of the costly materials with cheaper, more abundant ingredients along with utilizing inexpensive deposition methods like printing rather than vacuum-based methods such as evaporation and sputtering. Carbon materials attract more attention in the solar cell research community for their...
Response of a novel beam-to-column/brace-to-frame connection to monotonic and cyclic shear loading
, Article Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE, 9 June 2008 through 13 June 2008, Berlin ; Volume 2 , 2008 , Pages 609-618 ; 9780791848197 (ISBN) ; England, G. L ; Abazarsa, F ; Ocean, Offshore, and Arctic Engineering Division; ASME ; Sharif University of Technology
2008
Abstract
A new universal structural joint was developed. While in bending it has a high rotational capacity, which can be accompanied by large bending stiffness and strength, in shear, it also has a very high shear deformation capacity, which can again be accompanied with large shear stiffness and strength. While the former characteristic makes it a good candidate for being used as a beam-to-column joint, the latter makes it highly applicable in connecting braces of a braced frame to the frame members. The experimental study carried out previously on this joint, concentrated on the performance of its steel specimens under 'monotonie' shear loading as well as that of its aluminium specimens under both...
Considering wave passage effects in blind identification of long-span bridges
, Article Conference Proceedings of the Society for Experimental Mechanics Series ; Volume 5 , 2013 , Pages 53-66 ; 21915644 (ISSN); 9781461465638 (ISBN) ; Ghannad, M. A ; Norman, J ; Crewe, A ; Abazarsa, F ; Taciroglu, E ; Sharif University of Technology
2013
Abstract
Long-span bridges usually experience different input excitations at their ground supports that emanate from differences in wave arrival times, and soil conditions, as well as loss of coherency in arriving waves. These spatial variations can drastically influence the dynamic response; hence, this phenomenon must be considered in any vibration-based identification method. There are numerous Multi-Input Multi-Output (MIMO) identification techniques that may be applied to data recorded at long-span bridges that experience spatial variations in their input motions. However, inertial soil-structure interaction effects severely reduce the accuracy of these techniques because the actual Foundation...