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Analysis of Pulse to Pulse Regulation in the High Voltage Pulse Generators

, M.Sc. Thesis Sharif University of Technology Parvari, Ramin (Author) ; Kaboli, Shahriyar (Supervisor)

Abstract

High voltage pulse generators are widely used in the radar systems, laser, medical, food processing and etc. One of the pulse quality criteria that was analysed in this thesis is the pulse to pulse regulation. Pulse to pulse regulation is important in various fields. In the radar applications pulse to pulse instability caused undesired errors in the signal processing and limitations in the tracking of the targets. In Free Electron Lasers (FELs) non identical pulses cause RF phase shift in the each pulsed power supply and creates instabilities in the electron beam. Pulse quality is essential in medical application so that in the treatment of cancer an improved precision in delivering the...

RCD snubber design based on reliability consideration: A case study for thermal balancing in power electronic converters

, Article Microelectronics Reliability ; Volume 88-90 , 2018 , Pages 1311-1315 ; 00262714 (ISSN) Parvari, R ; Zarghani, M ; Kaboli, S ; Sharif University of Technology

Elsevier Ltd 2018

Abstract

In a turn-off RCD snubber, the capacitor value is usually optimized in order to minimize the power dissipated in the switch and snubber circuit. However, it may not be the best value of the snubber capacitor from the reliability point of view. In this paper, the capacitor value is optimized based on reliability considerations. Proposed method presents a new design to achieve the maximum reliability for the set of switch and its snubber. Mathematical analysis of the proposed method is conducted in MATLAB environment. Also, the experimental results are presented for validity of the theoretical analysis. © 2018 Elsevier Ltd

Finding an unknown object by using piezeoelectric material: A finite element approach

, Article 2nd International Conference on Environmental and Computer Science, ICECS 2009, 28 December 2009 through 30 December 2009, Dubai ; 2009 , Pages 156-160 ; 9780769539379 (ISBN) Azizi, A ; Durali, L ; Zareie, S ; Parvari Rad, F ; Sharif University of Technology

IEEE 2009

Abstract

This paper presents a method to determine material of an unknown sample object. The main objective of this study is to design a database for specifying material of an object. We produce the database for different materials which is subjected to different forces. For this purpose we use a Polyvinidilene Fluoride (PVDF) sensor which is a piezoelectric material. Also we study the effect of changing place of sensor on our study. The detailed design was performed using finite element method analysis. Furthermore, if we have an object which we do not know its material by use of this database we can find out what this object is and how much its Yanoung's modules is. This study will be suitable for...

On the complexity of isoperimetric problems on trees [electronic resource]

, Article Discrete Applied Mathematics ; Volume 160 Issue 1-2, January, 2012 Pages 116-131 Daneshgar, A. (Amir) ; Javadi, Ramin ; Sharif Univercity of Technology

Abstract

This paper is aimed at investigating some computational aspects of different isoperimetric problems on weighted trees. In this regard, we consider different connectivity parameters called minimum normalized cuts/isoperimetric numbers defined through taking the minimum of the maximum or the mean of the normalized outgoing flows from a set of subdomains of vertices, where these subdomains constitute a partition/subpartition. We show that the decision problem for the case of taking k-partitions and the maximum (called the max normalized cut problem NCP^M), and the other two decision problems for the mean version (referred to as IPP^m and NCP^m) are NP-complete problems for weighted trees. On...

On nodal domains and higher-order Cheeger inequalities of finite reversible Markov processes [electronic resource]

, Article Stochastic Processes and their Applications ; Volume 122, Issue 4, April 2012, Pages 1748–1776 Daneshgar, A. (Amir) ; Javadi, Ramin ; Miclo, Laurent ; Sharif Univercity of Technology

Abstract

Let LL be a reversible Markovian generator on a finite set View the MathML sourceV. Relations between the spectral decomposition of LL and subpartitions of the state space View the MathML sourceV into a given number of components which are optimal with respect to min–max or max–min Dirichlet connectivity criteria are investigated. Links are made with higher-order Cheeger inequalities and with a generic characterization of subpartitions given by the nodal domains of an eigenfunction. These considerations are applied to generators whose positive rates are supported by the edges of a discrete cycle ZNZN, to obtain a full description of their spectra and of the shapes of their eigenfunctions, as...

On the isoperimetric spectrum of graphs and its approximations [electronic resource]

, Article Journal of Combinatorial Theory, Series B ; Volume 100, Issue 4, July 2010, Pages 390–412 Daneshgar, A. (Amir) ; Hajiabolhassan, Hossein ; Javadi, Ramin ; Sharif University of Technology

Abstract

In this paper1 we consider higher isoperimetric numbers of a (finite directed) graph. In this regard we focus on the nth mean isoperimetric constant of a directed graph as the minimum of the mean outgoing normalized flows from a given set of n disjoint subsets of the vertex set of the graph. We show that the second mean isoperimetric constant in this general setting, coincides with (the mean version of) the classical Cheeger constant of the graph, while for the rest of the spectrum we show that there is a fundamental difference between the nth isoperimetric constant and the number obtained by taking the minimum over all n-partitions. In this direction, we show that our definition is the...

Exact Dynamic Simulation and Control for Hydrotreating Unit of Tehran Refinery

, M.Sc. Thesis Sharif University of Technology Shabanian, Jaber (Author) ; Bozorgmehri, Ramin (Supervisor)

Abstract

Since steady state behavior of a plant is affected by the change of various inputs to the plant, the transient behavior of the chemical plants are also very important in their general performance. On the other hand, catalytic hydrotreating is one of the most important processes in crude oil refining process in many aspects such as economical, technical and environmental. Thus, the goal of this project was dynamic simulation and control of catalytic hydrotreating unit (UNIFINER Unit) of Tehran Refinery with using the HYSYS software. To fulfill this target, data that were necessary for simulation were gathered from Unifiner unit of Tehran refinery at first. Then, steady state simulation of the...

Object Oriented Plantwide System Identification with Black Box Model

, M.Sc. Thesis Sharif University of Technology Ghorbani, Morteza (Author) ; Bozorgmehry, Ramin (Supervisor)

Abstract

In control engineering we want to set dynamic behavior of the system to a desired one and having a model that simulate systems behavior is necessary . System identification is a branch of chemical engineering that provide us this model , which divided into different branches itself . In this project we use object oriented programming to design and implement a software that support black box models such as Neural networks in addition to Mechanistic models (Which was implemented in previous project ) for identification . We use UML and C++ language in C++ Borland Builder in this project

Modeling Solar Hydrogen Fuel Cell System for Residential Application

, M.Sc. Thesis Sharif University of Technology Sayedin, Farid (Author) ; Roshandel, Ramin (Supervisor)

Abstract

The gradual exhaustion of oil and gas resources and the various problems involved in their pollution makes it necessary to promote a renewable energy system. One of the most interesting developments of standalone systems based on the utilization of hydrogen is solar hydrogen system. Central and southern Iran exhibit an excellent solar climate which makes them ideal places for solar hydrogen systems. The economy of Iran is based on oil and it has one of the largest reserves of oil and gas in the world but the reserves would not be enough to meet the domestic and export markets starting in three to four decades. Moreover, elimination of energy subsidies in Iran, will led to more tendencies to...

Modeling and Optimization of Solar Cooler for Domestic Usage

, M.Sc. Thesis Sharif University of Technology Bahrami, Mahdi (Author) ; Roshandel, Ramin (Supervisor)

Abstract

In this thesis a general model for simulation of solar cooler for domestic usage is developed. The model consists of 2 main parts: thermo-dynamical and economical calculations. The thermodynamic part consists of 4 sub models: a model for calculation of incoming solar radiation, cooling load demand calculation, the refrigeration cycle and the solar cycle with heat storage.As for hourly calculation of system performance part of the model produces the hourly received radiation data based on geographical position and orientation of the receiving surface. Base on results of the cooling load calculation for a 9 m2 studying room located in western part of Tehran, 1 TBR (3.516 kW) is chosen as...

Study of Interaction Between Environmental and Design in Optimization of Chemical Processes

, M.Sc. Thesis Sharif University of Technology Hemmaty, Mostafa (Author) ; Bozorgmehri, Ramin (Supervisor)

Abstract

Traditionally, chemical Process design is focused on the selection of technologies and optimization based on economic consideration .In the 1970’s because of the global energy crisis, other consideration consider with economic goals .in this study we are eager to provide design procedures and guidance for optimizing chemical processes simultaneously based on economic and environmental aspects .this optimization is applied to production maleic anhydride(MA) from n-butane feedstock .an optimization algorithm based on the genetic algorithm with four decision variables(recycle flow ratio ,air to feed ratio ,solvent flow and reactor temperature ).for including dynamic objective in optimization...

Design, Construction and Analysis of Fuel Cell and Battery Hybrid Power System Based on Optimal Power Strategy

, M.Sc. Thesis Sharif University of Technology Ghodsian, Nasser (Author) ; Roshandel, Ramin (Supervisor)

Abstract

Focusing on fossil fuel to secure energy demand lead to big challenges. Hydrogen as alternative for fossil fuel has attracted a lot of attentions. Fuel cell with an electrochemical reaction which it’s byproducts are water and heat convert Hydrogen into electricity. High efficiency and low environmental pollution, persuade many researchers toward fuel cell commercialization. But problems such as high cost, high power oscillation and inertia, avoid fuel cell from significant development. One way to deal with these problems is using the fuel cell and battery hybrid system. In recent decade too many research has been made in utilizing this hybrid system in transportation. This project...

, M.Sc. Thesis Sharif University of Technology Ghods, Masoud (Author) ; Bozorgmehri, Ramin (Supervisor)

Abstract

Application of the advanced control techniques and information technology in the biomedical engineering have been the focal point of the research communities in biomedical engineering due to the rapid growth of the nonlinear control theories along with the computer hardware. In this work the application of differential geometry and globally linearizing control has been applied to efficiently control the first phase of HIV disease based on the HIV infection model proposed in the literature. All the efforts have been in the way to obtain a suitable scenario of drug administration to suppress and control the infection. In the proposed scenario, drug administration is time dependant and...

, M.Sc. Thesis Sharif University of Technology Ahmadi, Somayeh (Author) ; Roshandel, Ramin (Supervisor)

Abstract

Inappropriate effects of fossil fuels and conventional power generation systems on the environment have necessitated a sustainable energy system for the next decade by growing interests in renewable energy systems. The world’s most fast-growing renewable energy resource is the wind energy. The main problem of wind power is the power fluctuations at the load side caused by the variable nature of wind speed, and the main issue in case of remote locations is the long-term storage of power generated by wind turbines. Batteries can be used to store a limited amount of energy for a short time. Although new advances in this field have been achieved, most common type of batteries is hardly able to...

Design and Development of Control System to Optimize PEM Fuel cell Performance

, M.Sc. Thesis Sharif University of Technology Farshidian, Behzad (Author) ; Roshandel, Ramin (Supervisor)

Abstract

Fuel cells are a reliable technology for electrical power generation, widely regarded as a promising alternative for stationary and mobile applications. In order to supply vehicle required power, fuel cell must possess suitable transient response. In this work, a mathematical zero dimensional control-oriented model for a PEM fuel cell stack is developed. Afterwards, to increase the efficiency, four parameters including cathode air inlet flow rate, return manifold cross section area, anode hydrogen inlet flow rate and hydrogen humidity are optimized in different vehicle current demand. Also, in order to decrease water production inside the fuel cell membrane, considered parameters are...

Modeling and Optimization of Solid Waste Application in Combined Heat and Power System

, M.Sc. Thesis Sharif University of Technology Kolagar, Mina (Author) ; Roshandel, Ramin (Supervisor)

Abstract

increasing energy demand and emission of environmental pollutant as a result of using fossil fuels and increase in waste generated due to human activities resulted in considering this source as a partial substitute for fossil resources in power application . Hence in this project biomass is considered as source of energy for heat and power application. Having low quality energy is the most important difficulty for application this resource as an energy carrier, so, gasification is applied to convert this source to gas with higher quality one. Produced gas in gasification enters to a micro turbine to meet thermal and electrical demand of the Sharif energy research institute. To investigate...

Development of an Intelligent System to Predict and Control Blood Glucose Level in Type 1 Diabetic Patients

, M.Sc. Thesis Sharif University of Technology Afsharpour, Alireza (Author) ; Bozorgmehri, Ramin (Supervisor)

Abstract

All living entities requires energy to continue their lives. In human beings this energy is provide through consumption of food, at first the consumed food gets converted to glucose and the produced glucose enters the blood and then goes to the body cells in which it is used to produce the required energy. The essential hormone which makes it possible to use Glucose for energy production is INSULIN. In the patients suffering from Type 1 Diabetes, lack of Insulin production makes it impossible for the cells to use Glucose for the production of their required energy. In these patients due to the fact that the blood Glucose is not used by the cells, the Blood Glucose Level (BGL) increases,...

Modeling and Analysis of Optimal Control and Condition Monitoring of Fuel Cell System Based on Performance History

, M.Sc. Thesis Sharif University of Technology Parhizgar, Tarannom (Author) ; Roshandel, Ramin (Supervisor)

Abstract

The short life of Polymer Electrolyte Membrane (PEM) fuel cells is one of the critical criteria to their commercialization. A longer operation life time should be achieved to reach high reliability, low $/kWh cost and to use fuel cells as economical alternative energy systems.Therefore,diagnosing degradation mechanisms and the causes of power loss in fuel cell life time is of great importance. Operating conditions affect output power density and performance degradation. To achieve maximum power generation through fuel cell life time, a model is needed which is able to estimate power density and performance degradation simultaneously regarding to operating conditions. In present work, a...

Development of a Framework to Control and Model Based Fault Diagnosis of a Gas Transmission Network

, M.Sc. Thesis Sharif University of Technology Kheradmandi, Masoud (Author) ; Bozorgmehry, Ramin (Supervisor)

Abstract

In this project a framework for Model Based Fault Diagnosis (MBFD) in a Gas Transmission Network (GTN) was developed. A black-box linear state-space model was used to capture dynamic behavior of an industrial benchmark for GTN. A full fledge commercial network simulator were used to obtain the required data for process identification. In order to check the robustness of the model zero mean white noise was imposed on various output obtained by the commercial simulator. Kalman filter was used to estimate the states of the GTN. These estimated states along with the measured output (all obtained from the commercial simulator) are almost similar to their corresponding estimated signal. This shows...

Optimal Sizing and Demand Management of Stand-Alone Solar System with Hydrogen Storage

, M.Sc. Thesis Sharif University of Technology Haddadi, Morteza (Author) ; Roshandel, Ramin (Supervisor)

Abstract

This current reseach concentrates on designing and evaluation of stand-alone alternative energy system which consists of a proton exchange membrane fuel cell system (PEMFC), a photovoltaic (PV) panel, a proton exchange membrane electrolyser and a hydrogen storage tank.. To establish the minimum capacity of the system components, a system sizing model is developed in MATLAB Based on meteorological and the electrical yearly demand data which are extracted from DEDM model. The accuracy of the sub models is checked by comparing the experimental measurements of the system components obtained from other literatures with model outputs. The evaluation is based on demand profile, investment costs,...