Analysis of a Ultra Narrow Pulse Width High Voltage Generator

, M.Sc. Thesis Sharif University of Technology Farajzadeh Galeh, Amin (Author) ; Kaboli, Shahriar (Supervisor)

Abstract

A Tesla charged PFL Bipolar pulsed power generator has been successfully designed and simulated. The compact Tesla transformer that it employs has successfully charged capacitive loads to peak voltages up to 0.6 MV . The Tesla–driven PFL generator is capable of producing a voltage impulse approaching .3 MV with generating a peak electrical power of up to 1.8 GW for 5 ns when connected to a matched resistive load. Potentially for medical application, a bipolar former has been designed and successfully simulated as an extension to the system and to enable the generation of a sinusoid-like voltage impulse with a peak-to-peak value reaching 600 kV and having a frequency bandwidth beyond 1 GHz....

Adaptive Modelling and Solution of Drone Logistic Service Composition in Cloud Supply Chain Considering Dynamic Condition

, M.Sc. Thesis Sharif University of Technology Farajzadeh, Fatemeh (Author) ; Hoshmand, Mahmoud (Supervisor)

Abstract

globalization has let suppliers to geographically distribute across the globe, and for accomplishing the final product resources need to be gathered. So, Cloud manufacturing is a new paradigm which provides ubiquitous, convenient, on-demand network access to a shared pool of configurable manufacturing resources distributed across the globe. On the other hand, in recent years the product delivery system has faced a significant amount of changes with reducing cost and waiting time of last-mile delivery. Unmanned aerial vehicles, or drones, have the potential to deal with these issues effectively. This research developed a mathematical formulation to investigate the optimum routing and...

Bifurcation structure of two coupled FHN neurons with delay

, Article Mathematical Biosciences ; Volume 270 , 2015 , Pages 41-56 ; 00255564 (ISSN) Farajzadeh Tehrani, N ; Razvan, M ; Sharif University of Technology

Elsevier Inc 2015

Abstract

This paper presents an investigation of the dynamics of two coupled non-identical FitzHugh-Nagumo neurons with delayed synaptic connection. We consider coupling strength and time delay as bifurcation parameters, and try to classify all possible dynamics which is fairly rich. The neural system exhibits a unique rest point or three ones for the different values of coupling strength by employing the pitchfork bifurcation of non-trivial rest point. The asymptotic stability and possible Hopf bifurcations of the trivial rest point are studied by analyzing the corresponding characteristic equation. Homoclinic, fold, and pitchfork bifurcations of limit cycles are found. The delay-dependent stability...

Global analysis of a delay SVEIR epidemiological model

, Article Iranian Journal of Science and Technology, Transaction A: Science ; Volume 37, Issue A4 , 2013 , Pages 483-489 ; 10286276 (ISSN) Farajzadeh Tehrani, N ; Razvan, M. R ; Yasaman, S ; Sharif University of Technology

2013

Abstract

This paper is concerned with global analysis of a delay SVEIR epidemiological model in a population of varying size. By using Lyapunov stability method and LaSalle's invariance principle for delay systems, we prove that when there is no endemic equilibrium, the disease free equilibrium is globally asymptotically stable, otherwise the endemic equilibrium is globally stable

Multiple Eguilibria In Chemical Reaction Systems

, M.Sc. Thesis Sharif University of Technology Farajzadeh Tehrani, Niloofar (Author) ; Razvan, Mohammad Reza (Supervisor)

Abstract

In modeling of biological systems and chemical reaction networks, analy-sis the existence of multiple equilibria is important. Our interest in using dynamical system in such analyses comes from biology. So, we will study the qualitative properties of a dynamical system, described by a system of ordinary differential equations. In this thesis we will discuss the question of how to decide when a general chemical reaction system is incapable of admitting multiple euilibria, regardless of parameter values such as reaction rate constants. We will relate different graphs to chemical reaction systems, and by means of its paths and circuits, we will introduce some sufﬁcient conditions for...

Dynamics of Delayed Neuronal Systems

, Ph.D. Dissertation Sharif University of Technology Farajzadeh Tehrani, Niloofar (Author) ; Razvan, Mohammad Reza (Supervisor)

Abstract

This thesis presents an investigation of the dynamics of two coupled non-identical FitzHugh–Nagumo neurons. It is known that signal transmission in coupled neurons is not instantaneous in general, and time delay is inevitable in signal transmission for real neurons. Therefore we consider the system of two coupled neurons with delayed synaptic connection. We consider coupling strength and time delay as bifurcation parameters, and try to classify all possible dynamics which is fairly rich and we will study the excitability of the neurons. By bifurcation study of the system the coupling strength and delay-dependent stability regions are illustrated in the parameter plane, to describe typical...

Investigation of Mechanical Properties of Particulate Metal Matrix Nanocomposites Using Surface Elasticity Theory

, M.Sc. Thesis Sharif University of Technology Farajzadeh Moshtaghin, Alireza (Author) ; Naghdabadi, Reza (Supervisor) ; Asghari, Mohsen (Supervisor)

Abstract

Excellent mechanical properties and high aspect ratio of carbon nanotubes have been the reason for extensive research on nanocomposites reinforced by this nanostructure, and recently metal matrix type of these nanocomposites, due to their advantages, have received great attention. Moreover, nanoporous materials are another type of nanostructured materials which due to their very high porosity have special applications in hydrogen storage, separating molecules, purification and energy absorption. Because of completely neglecting the details of nanoscale structure and not paying attention to the length scale, classical continuum mechanics methods are not precise enough for evaluating different...

Introducing a Simulation-Based Model to Improve the Design and Layout of Workstations Inside Airport Terminals in Iran

, M.Sc. Thesis Sharif University of Technology Amini Esfidvajani, Amin Mohammad (Author) ; Alvanchi, Amin (Supervisor)

Abstract

The airport terminal is difficult to plan and design due to the different components and the intricate complexity of its parts. At the airport terminal, we face a queue system which simulation is always a good way to analyze. In addition, computer simulation using modern softwares with the capability to model different types of systems, including the airport terminal, while being less realistic than analytical models, is less costly than operational Exercise.In this study, a supportive approach for better and specific management of Iranian airport terminal buildings with discrete-event simulation is proposed, considering the need for managing the airport terminals building in the country and...

Apoptosis induction, cell cycle arrest and anti-cancer potential of tamoxifen-curcumin loaded niosomes against MCF-7 cancer cells

, Article Iranian Journal of Pathology ; Volume 17, Issue 2 , 2022 , Pages 183-190 ; 17355303 (ISSN) Fatemizadeh, M ; Tafvizi, F ; Shamsi, F ; Amiri, S ; Farajzadeh, A ; Akbarzadeh, I ; Sharif University of Technology

Iranian Society of Pathology 2022

Abstract

Background & Objective: Breast cancer is the most common cancer among women. One of the most effective treatments for breast cancer is chemotherapy, in which specific drugs destroy the mass and its proliferation is inhibited. Chemotherapy is the most effective adjunctive therapy when multiple medications are used concurrently. Also, combining the drugs with nanocarrier has become an important strategy in targeted therapy. This study is designed to assess the apoptosis induction, cell cycle arrest, and anti-cancer potential of Tamoxifen-Curcumin-loaded niosomes against MCF-7 Cancer Cells. Methods: A novel niosomal formulation of tamoxifen-curcumin with Span 80 and lipid to drug ratio of 20...

, M.Sc. Thesis Sharif University of Technology (Author) ; Alvanchi, Amin (Supervisor)

Abstract

Limited water resources in Iran have made dams an important part of the country’s infrastructure. As a result of the large number of in-progress and expected dam projects in the country, consideration of sustainability factors during planning, construction and operation phases of dam projects can create significant economical, social and environmental impacts in the long term. To come up with an inclusive sustainable development, new sustainability assessment approaches seek for sustainable development at the entire project’s life-cycle; they are looking for sustainable development at all design, construction, operation, maintenance and even demolition phases. In this research we have...

The Insider Threat: Analyzing and Modeling

, M.Sc. Thesis Sharif University of Technology Amin, Assiabi (Author) ; Hendesi, Faramarz (Supervisor)

Abstract

Nowadays, most of businesses are becoming computer-based. This trend causes the organizations to become more vulnerable to internal and external threats. Internal threats are done through insiders. Insiders unlike outsiders have capabilities which aid them to easily carry out their illicit activities. Unfortunately, most of research in computer security has focused on the outsider threats, whereas the most damaging is the result of insiders’ illicit activities.This dissertation addresses three primary necessities of the research in the area of insider threat: a consistent definition of insider threat, a classification of types of insider threats, and a classification of vulnerabilities which...

Design of a Plantwide Decentrlized Structure Controller for the Tennessee Eastman Challenge Problem

, M.Sc. Thesis Sharif University of Technology Molamofrad, Foozhan (Author) ; Nobakhti, Amin (Supervisor)

Abstract

This project focuses on the Tennessee East-man challange problem(TEP) and the impact of setpoint changes and controller tunning on plant performance and profitability. TE has four major units. it is an unstable system due to the reaction within the reactor and a recycle streamcausing snow ball effect. As a result the control of this system is not easy. The study has been conducted along two main directions. First, selecting the optimal values for the setpoints and applying them in the simulation. secondly, try to find better parameter for controller in simulation. Simulation is based on working of Ricker. In TEP like the other multivariable systems, it is ameanable to use a centralized...

Convex Methods for the Design of Low Order Dynamic Pre-Compensators

, M.Sc. Thesis Sharif University of Technology Shamgah, Laya (Author) ; Nobakhti, Amin (Supervisor)

Abstract

Decentralized control is a typical method for the design of industrial MIMO control systems. However, in most multivariable systems, the existence of large interactions limit the achievable performance of such controllers. In the Nyquist Array design method proposed by Rosenbrock, the system interactions can be reduced using a precompensator, such that a decentralized controller may be used with acceptable performance. A well designed pre-compensator will effectively decouple the system and the multivariable systems may be considered as a set of SISO systems. It is therefore obvious that the key element in the Nyquist Array design method is the design of the pre-compensator. There are two...

Integrity Analysis in the Time-Delay Systems

, M.Sc. Thesis Sharif University of Technology Eslami, Mostafa (Author) ; Nobakhti, Amin (Supervisor)

Abstract

Integrity of closed-loop systems with integral action control is characterized by using a series of successively more difficult to obtain conditions: Integral Stabilizable (IS), Integral Controllable (IC), Integral Controllable with Integrity (ICI), and Decentralized Integral Controllability (DIC). The IS condition requires that for a Linear Time-Invariant (LTI) finitedimensional (FD) plant, G(s), one finds a stabilizing decentralized controller with integral action. For G(s) to be IC, in addition to being IS, one should be able to reduce the gain of
all control loops by the same factor from a finite value to (but not including) zero without introducing instabilities. ICI requires that...

A Thesis Submitted in Partial Fulfillment of the Requirement for the Degree of Master of Science in Electrical Engineering

, M.Sc. Thesis Sharif University of Technology Negim, Mostafa (Author) ; Nobakhti, Amin (Supervisor)

Abstract

Intraction in multi input multi output (MIMO) system makes control of these systems difficult.There are two ways to control such systems; Centralized and Decentralized control. One way in which a centralized controller is designed is using a precompensator. With application of the pre-compensator, the MIMO sytem is decoupled into several SISO systems and one can control these seperatly. Almost all previews methods for the design of pre-compensator assume that the model of the plant containsno uncertainties.In this thesis a new method is proposed which takes into account model uncertaintes in the design of the pre-compensator.The form of the uncertainties considred an interval-parametric

Conditions for Integrity of Multivariable Systems with Input Saturation

, M.Sc. Thesis Sharif University of Technology Asgharzadeh, Abbas (Author) ; Nobakhti, Amin (Supervisor)

Abstract

Multivariable control systems as used in the industry usually contain integral action in order to improve tracking of the output with respect to step reference changes. These systems are usually subject to input saturation due to actuator or sensor nonlinearities. The aim of this work is find the conditions for the integrity concept of such multivariable system, e.g. IS, IC, ICI and DIC. First we develop the conditions on the controller gains necessary stabilize the systems and then show that these conditions can changes when one examines integrity conditions

Disturbance Reduction Servo Motor Controller Design and Implementation

, M.Sc. Thesis Sharif University of Technology Ahi, Behzad (Author) ; Nobakhti, Amin (Supervisor)

Abstract

The servomechanisms have wide industrial application such as robotics, Computer Numerical Control (CNC) machines, automated manufacturing and solar tracking. Several methods have already been proposed for servo motor control that the most important of them are Proportional Integral Derivative (PID), H2/H--, intelligent based controllers, and model predictive control. Problem specifications and user requirements, will determine the appropriate approach in each case. The aim of this thesis is construction of a real-life camera stabilizer to be used in the motion picture industry. Effects of base movement on the performance should be decreased by choosing appropriate sensors and control...

Disturbance Diagnosis In Plant-wide Processes

, M.Sc. Thesis Sharif University of Technology Juyandeh, Sepideh (Author) ; Nobakhti, Amin (Supervisor)

Abstract

In continous chemical process, disturbances usually propagate along the process. This project describes a data-driven method for identifying the direction of propagation of disturbances using historical process data. The concept is the application of Transfer Entropy, a method based on the conditional probability density functions that measures directionality of variation. For demonstration purposes the transfer entropy method is used to isolate the root-cause of the disturbance in the Tennassee Eastman benchmark process

Optimization of Sparse Control Structures in Multivariable Systems

, Ph.D. Dissertation Sharif University of Technology Babazadeh, Maryam (Author) ; Nobakhti, Amin (Supervisor)

Abstract

In this thesis, the optimal control structure selection and design of sparse multi-variable control systems is addressed. A fundamental challenge which frequently emerges in engineering, social, and economic sciences, is the optimal selection of a subset of elements, in order to maximally fulfil a design objective. In practice, it is required to solve this underlying selection problem in conjunction with a non-linear or non-convex optimization which is designed to ensure desired performance. The requirement to solve these two problems simultaneously is what makes it inherently difficult; one which has thus far eluded efforts to develop a systematic means of determining its solution. In spite...

Decentralized Integral Controller Design to Possess Integrity

, M.Sc. Thesis Sharif University of Technology Sinafar, Behzad (Author) ; Nobakhti, Amin (Supervisor)

Abstract

Design of fault tolerant controllers with a reliable and robust control structure that can accommodate sensor and actuator failure is a challenging problem. In the process control literature, the term “integrity” is used to characterize these properties for decentralized control systems. It refers to the ability to retain system stability when one or some of the control loops get in or out of service or when loop gains are detuned.Conditions pertaining to the integrity of the closed-loop system are described by a series of successively more difficult to attain criteria whose evaluation is only based on the process steady state gains. These are Integral stabilizibility (IS), Integral...