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pishvaie--mahmoud-reza
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Total 91 records
Analysis of Forced Periodic Production of Continuous Bioreactors
, M.Sc. Thesis Sharif University of Technology ; Pishvaie, Mahmoud Reza (Supervisor)
Abstract
Recently experiences in chemical processes approved that periodic operation for some of the processes (e.g. ion exchangers, activated sludge tanks, etc) were being successful. The performance and/or effectiveness of process due to periodic changes in the systems input, such as concentration, feed or coolant temperature and other possibilities, typically express whether in term of yield or selectivity improvement. Though, prominent issue in this type of dynamical control problem is optimal frequency and amplitude in the cycle. Supporting mathematics, include two main approaches: (1) the Hamilton-Jacobi approach based on the maximum principle and (2) a frequency domain approach using second...
Optimal Control of Chemical Reactors Based on Optimization Methods Inspired from Artificial Immune Systems
, M.Sc. Thesis Sharif University of Technology ; Pishvaie, Mahmoud Reza (Supervisor)
Abstract
Artificial immune systems (AIS) constitute a novel area of bio-inspired computing. Biological models of the natural immune system, in particular the theories of clonal selection, immune networks and negative selection, have provided the inspiration for AIS algorithms. Moreover, such algorithms have been successfully employed in a wide variety of different areas, but have not been applied for chemical processes yet. One important part of the immune systems is lymphatic system. Clonal selection is one of the few algorithms that belong to the family of AIS techniques. Clonal selection algorithm is the computational implementation of the clonal selection principle. In this project, we have...
Optimal Control of Electrochemical Treatment of Tumors
, M.Sc. Thesis Sharif University of Technology ; Pishvaie, Mahmoud Reza (Supervisor)
Abstract
In this project, we have assessed the electrochemical treatment method. In this method, pH decrease of the place where a tumor is located engenders the necrosis of cancer cells and consequently they are destroyed. The process of pH decrease is caused by exerting voltage on electrods that are located near the tumor. The aims of optimizing this methods are to minimize the pH that results in the increase of cancer cell annihilation and to minimize the HClO and Cl2 products which are toxic and chage the healthy tissues to cancer cells. In this project, the model of electrochemical treatment method is explained, and then this model is simulated using the parametes which are provided in the...
Optimal Control of Batch Cooling Crystallizers Using Inversion Approach
, M.Sc. Thesis Sharif University of Technology ; Pishvaie, Mahmoud Reza (Supervisor)
Abstract
In batch cooling crystallization, the crucial control problem is to design a temperature trajectory which produces a desired crystal size distribution. Here, a completely different solution is presented. Designing model-based controller for crystallizer has two steps; first step is determining optimal temperature trajectory which is some kind of feedforward control, second step is adding feedback controller (with manipulated variable of jacket temperature or cooling flow) to track the set-point (determined in first step) and rejecting possible disturbances. Traditionally, determining optimal temperature of crystallizer is done by using calculus of variations of distributed system. In this...
Model Predictive Control of pH in Electrochemical Treatment of Tumors
, M.Sc. Thesis Sharif University of Technology ; Pishvaie, Mahmoud Reza (Supervisor)
Abstract
Electrochemical treatment of tumors introduces cancer therapy method that uses direct current which passes through cancer tissue. The manipulated variable (direct current density) is applied to the surface of the electrode. As a result of applying direct current on the anode's surface, two competition reactions start to happen on the electrode's surface, Chlorine and Oxygen evolutions. The productions of these two reactions for instance Cl_2 , Cl^- and H^+ caused different reactions in the domain of the electrolyte which is the body tissue. According to the buffer characteristic of blood and organic features of tissue, various types of acids like HClO form in the electrolyte. If the pH in...
Modeling and Characterizing Transient Behavior of Distillation Columns with Travelling Wave Theory
, M.Sc. Thesis Sharif University of Technology ; Pishvaie, Mahmoud Reza (Supervisor)
Abstract
Simulation and controlling nonlinear process is one of the challenging problems in academic and industrial research. Saving data for keeping history of process or arising number of calculation for optimization in control design, is forcing to decrease number of equation or order of system. One of the methods to decrease the order of distillation process is using the travelling wave theory. This solution shows god accuracy for simulation the behavior of distillation column. On the other hand finite difference method as a solver for distillation equation takes some time to converge to steady state condition and the numbers of calculation in this method are high. Finite difference method is...
Simulation and Control of Solid Oxide Fuel Cell
, M.Sc. Thesis Sharif University of Technology ; Pishvaie, Mahmoud Reza (Supervisor)
Abstract
The advent of maturing fuel cell technologies presents an opportunity to achieve significant improvements in energy conversion efficiencies at different scales and environmental conservation simultaneously. This work deals with modeling, simulation and control of planar solid oxide fuel cell with internal reformer. The presented model is based on conservation laws (mass, energy, and momentum), besides an electrochemical model with all sorts of voltage losses (ohmic losses, activation overpotentials, and concentration overpotentials). Methane steam reforming, water-gas shift reaction, and hydrogen oxidation are the main reactions in this modeling scheme. The obtained governing equations lead...
Multi Variable Generalized Predictive Control of a Solution Copolymerization Reaction
, M.Sc. Thesis Sharif University of Technology ; Pishvaie, Mahmoud Reza (Supervisor)
Abstract
Continuous synthesis of different kinds of industrial copolymers plays an important role in economics of the polymer industry. But copolymerization reactions are complex and with a high degree of nonlinearity so the control problem in this case needs a detailed study on system dynamic behavior. One of the solutions is using a optimal control method in the shape of predictive controllers. The main goal in this thesis is to design a generalized multi-varriable predictive controller for a solution copolymerization of methyl methacrylate and vinyl acetate in a continuous stirred tank reactor with separator and recycle stream. In this study, after simulating the nonlinear model of the process...
Simulation and Design of Multi-Variable Fuzzy Controller for CSTR Polyvinyl Acetate
, M.Sc. Thesis Sharif University of Technology ; Pishvaie, Mahmoud Reza (Supervisor)
Abstract
There is many Nonlinear process in industry which are not control able with classic control methods. Model predictive control is a very useful method of control for nonlinear processes.
The nonlinearity of polymerization reactors are considerable in modeling, simulation, dynamic study and control .Design of free radical polymerization in continues reactors are very populated in industries.in this thesis modeling of free radical polymerization for polyvinyl acetate in industrial scale is studied for dynamic behavior studies of CSTR and design of Model predictive control system for the CSTR.
One of the important challenges in control system for this reactor is the existence of delay...
The nonlinearity of polymerization reactors are considerable in modeling, simulation, dynamic study and control .Design of free radical polymerization in continues reactors are very populated in industries.in this thesis modeling of free radical polymerization for polyvinyl acetate in industrial scale is studied for dynamic behavior studies of CSTR and design of Model predictive control system for the CSTR.
One of the important challenges in control system for this reactor is the existence of delay...
Optimal Nonlinear Control of Poly Vinyl Acetate CSTR
, M.Sc. Thesis Sharif University of Technology ; Pishvaie, Mahmoud Reza (Supervisor)
Abstract
Nonlinear nature of polymerization reactors has always attracted great attentions in various scientific areas such as modeling, simulation, dynamical behavior investigation and control engineering as well. Free radical polymerization in continuous reactors, whether in terms of design and startup or in terms of economical concerns, has numerous fans in industrial aspects. In the following thesis, the dynamical behavior of continuous stirred tank reactor of Vinyl Acetate free radical polymerization is examined in an industrial scale. A control system with optimum performance is designed for this CSTR as well. According to the common behavior of this type of reactor, it may demonstrate...
State Feedback Control Proton Exchange Membrane Fuel Cell (Pem) Stack
, M.Sc. Thesis Sharif University of Technology ; Pishvaie, Mahmoud Reza (Supervisor)
Abstract
In recent years, fuel cells have been proposed as an alternative option to conventional energy conversion systems. Fuel cell is an electrochemical system that can convert chemical energy to electrical energy without combustion. High efficiency, low temperature performance, poor pollution, good reliability, flexibility in the production potential, low start-up time and high life expectancy are the major advantages of this system. The most important barriers to the use of fuel cells are high cost polymer membrane and using expensive platinum catalysts. Modeling of fuel cells in general will meet two objectives. The first, due to the complexity of the processes taking place within the cell,...
Proposition of Control Structure for DME Synthesis Plant
, M.Sc. Thesis Sharif University of Technology ; Pishvaie, Mahmoud Reza (Supervisor)
Abstract
The development and use of design methods for control structures has grown significantly in recent decades. In this study, a systematic plantwide control procedure proposed by Skogestad, has been used. The main idea of suggested method is based on the self-optimizing variables. One of the advantages of this method of designing a control structure is considering the economic optimization of the process in most stages of its implementation. The indirect and direct dimethyl ether synthesis from natural gas feed have been investigated in this study. In this research, indirect and direct dimethyl ether synthesis processes are simulated with Aspen Plus V10 and degree of freedom analysis is done....
Simulation and Model Predictive Control of CO2 Capture Plants From Flue Gas
, M.Sc. Thesis Sharif University of Technology ; Pishvaie, Mahmoud Reza (Supervisor)
Abstract
Continued uncontrolled gas emission can cause extreme changes in climate all over the world and threaten the life So, the removal and/or reduction of CO2 from the atmosphere is essential to prevent its side effects. CO2 separation is the costliest part of the gas removal process from fossil fuel combustion. Among several available CO2 capture technologies, the MEA-based post-combustion CO2 capture process is considered a mature technology for mitigating CO2 emissions. In this study a steady-state MEA-based CO2 capture process from the coal power plant is developed in Aspen Plus. Subsequently, steady-state model with appropriate modifications, is exported into Aspen Plus Dynamics to study...
Dynamic Simulation and Control of an Lng Production Unit
, M.Sc. Thesis Sharif University of Technology ; Pishvaie, Mahmoud Reza (Supervisor)
Abstract
Today, shipping of liquefied natural gas has a considerable share in the global gas trade. Efficient design, optimal operation, and precise control of process variables in the gas liquefaction process decrease energy consumption for LNG production. Understanding the dynamic behavior of a liquefied natural gas unit helps engineers to make the correct choice of controlled variables and tuning controllers. Through a dynamic simulation, this understanding can be achieved. Simulation of a multi-stream heat exchanger, as the heart of the gas liquefaction process, is a challenge of studying this process. In this study, two dynamic models governing a multi-stream heat exchanger in Aspen Plus...
Model Predictive Inferential Control for Electrochemotherapy of Tumors
, M.Sc. Thesis Sharif University of Technology ; Pishvaie, Mahmoud Reza (Supervisor)
Abstract
The purpose of this project is to use adaptive model predictive and fuzzy controllers to control the pH in a proper location and right amount as well as applying optimal dose of electrical current to prevent the destruction of healthy tissue during treatment. Comsol software has been used to simulate the electrochemical treatment of liver cancer. Since the Comsol software does not have the ability to solve the tumor model in spherical coordinates, the modeling/simulation was performed in cylindrical ordinates. In this study, only the reactions of oxygen and chlorine production in the anode were considered. The predictive control used in this study is GPC type and fmincon algorithm is used...
Numerical Simulation of Acidizing (HCl)Process in Carbonate Reservoirs
, M.Sc. Thesis Sharif University of Technology ; Pishvaie, Mahmoud Reza (Supervisor)
Abstract
Carbonate Matrix acidizing in order to improve or increase initial permeability, leads to different dissolution patterns under different operating and environmental conditions. In a specific rock / reactive fluid system, when a reactive fluid injects into the system in an optimal velocity, the dissolution pattern proceeds like a finger, names Wormhole. Formation of Wormhole is known as a success in acidizing process, because of its optimum porosity and permeability evolution and minimum pore volume injected of reactive fluid to breakthrough. So prediction of optimum injection velocity and analysis of dissolution patterns variation by change in operational and environmental conditions,...
Dynamic Modeling of a Continuous Bioreactor Using Hybrid Neural Network
, M.Sc. Thesis Sharif University of Technology ; Pishvaie, Mahmoud Reza (Supervisor)
Abstract
Dynamic modeling and control of bioprocesses, especially bioreactor and fermenter equipment, has always faced many challenges due to their complexity and high uncertainty. One scientific approach to modelling of such complex systems is the use of neural networks. Recently, an approach called hybrid networks has become popular, whose structure incorporates some of the basic rules, such as the mass balance of reactive species. Practically, it can also be used as a ‘software sensor’ or non-measurable state estimator. In this project, a bread yeast production bioreactor is used as a reference process and a hybrid neural network is used to estimate unknown parameters of biochemical reactions. In...
Immunotherapy of Cancer Tumors Using Model Predictive Control Approach
, M.Sc. Thesis Sharif University of Technology ; Pishvaie, Mahmoud Reza (Supervisor)
Abstract
Statistics show that cancer is the second leading cause of death in the world. In recent years, several studies have shown that combination therapy is more effective than single therapy. Modeling and simulation the dynamics of cancer and the immune system and controlling the dose of cancer drugs complement preclinical trials. The aim of this study was to apply the model predictive control approach to determine the optimal dose of chemotherapy and immunotherapy drugs to treat cancerous tumors. Thus, with a preliminary analysis of the analytics, a six-state dynamic model has been selected as a hypothetical patient to advance therapeutic goals. Two sets of parameters for the hypothetical...
Development of Low-order Model/controllers for Oil Reservoir Smart Wells
,
M.Sc. Thesis
Sharif University of Technology
;
Pishvaie, Mahmoud Reza
(Supervisor)
Abstract
Upstream oil industry operators have turned to optimal production methods for further recoveries, such as smart wells. Control algorithms for smart wells must be equipped with online measurements, in other words, reflected in the feedback philosophy. On the other hand, after discretization, an oil reservoir's dynamic and control-driven model becomes a realization or a large-scale and sparse state space. One way to deal with this problem and provide an appropriate model for the design of smart well controllers is to use appropriate reservoir dimensional reduction methods. Therefore, to design low-order controllers, a study must first be performed at the level of the reservoir model and its...
Accelerating Flash Calculations in Compositional Simulators Using Machine Learning Algorithms
, M.Sc. Thesis Sharif University of Technology ; Pishvaie, Mahmoud Reza (Supervisor)
Abstract
Flash calculations using equations of state are the basis of compositional simulators and inaccuracy in these calculations leads to errors in some time steps or even complete failure of a simulation. One of the problems of this approach is the use of iterative loops, which leads to a high computational cost. The purpose of this research is to use deep machine learning methods, namely multi-layer perceptrons and convolutional neural networks to solve this problem. At first, we defined two 5-component and 10-component hydrocarbon fluid models and used one of the conventional methods of flash calculations (Modified Successive Substitution method) in order to generate the data required for...