Manufacture & Design of a Programmable Micro Syringe for Injecting of Biodegradable Photo Polymers

, M.Sc. Thesis Sharif University of Technology Sheydaeian, Esmat (Author) ; Durali, Mohammad (Supervisor) ; Toyserkani, Ehsan (Co-Advisor)

Abstract

The micro-scale channel creation in Osteochondral scaffolds is a prominent issue in tissue engineering. In this project we tried to identify the relevant parameters to obtain the method for injecting a biodegradable photo polymer to achieve a micro channel by predictable size.Due to inadequate accuracy in measuring the properties of the non –Newtonian working fluid, it was decided to use the Newtonian fluid equations in this study. The relevant equations for injecting the liquid under constant pressure were extracted. The modeling and design of micro syringe system was then completed. Using the made set up experiment to measure the fluid viscosity were performed.The next step was the...

Adaptive modeling of laser powder deposition process for control and monitoring application

, Article JVC/Journal of Vibration and Control ; Volume 13, Issue 5 , 2007 , Pages 461-473 ; 10775463 (ISSN) Durali, M ; Fathi, A ; Khajepour, A ; Toyserkani, E ; Sharif University of Technology

2007

Abstract

The laser powder deposition (LPD) process is an advanced material processing technique with many applications. Despite this fact, reliable and accurate control schemes have not yet been fully developed for the process. In this paper, identification of the LPD process is examined to find a more accurate model to predict and control the height of clad in real time. The model is adaptive single inputsingle output (SISO) and its structure is very similar to the Hammerstein model when the effective power (a function of laser power and velocity) is selected as the input and the clad height as the output. Weighted extended recursive least square (WERLS) is adopted to simultaneously estimate the...

Geometry control of the deposited layer in a nonplanar laser cladding process using a variable structure controller

, Article Journal of Manufacturing Science and Engineering, Transactions of the ASME ; Volume 130, Issue 3 , 2008 , Pages 0310031-03100311 ; 10871357 (ISSN) Fathi, A ; Khajepour, A ; Durali, M ; Toyserkani, E ; Sharif University of Technology

2008

Abstract

This paper presents a closed-loop laser cladding process used in nonplanar deposition of desired metallic materials. In the proposed system, the deposited layer geometry is continuously controlled via a sliding mode controller (SMC). The controller, which uses the scanning speed as the control input, is designed based on a parametric Hammerstein model. The model is a parametric dynamic model with several unknown parameters, which are identified experimentally using the recursive least squares method. The designed SMC is robust to all model parameters' uncertainties and disturbances. The results showed that the tracking accuracy improves and the chattering effect reduces if an integrator on...

Clad height control in laser solid freeform fabrication using a feedforward PID controller

, Article International Journal of Advanced Manufacturing Technology ; Volume 35, Issue 3-4 , 2007 , Pages 280-292 ; 02683768 (ISSN) Fathi, A ; Khajepour, A ; Toyserkani, E ; Durali, M ; Sharif University of Technology

2007

Abstract

In this paper, a feedforward proportional-integral-derivative (PID) controller is developed to effectively control the clad height in laser solid freeform fabrication (LSFF). The scanning velocity is selected as the input control variable and the clad height is chosen as the output. A novel knowledge-based Hammerstein model, including a linear dynamic and a nonlinear memoryless block, is developed, and its parameters are identified offline using experimental data. The architecture of the controller consists of a PID and a feedforward module, which is the inverse of the identified model. The advantage of adding a feedforward path to the PID controller is evaluated experimentally, in which the...

Adaptive modeling of powder deposition for control and monitoring application

, Article DETC2005: ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, Long Beach, CA, 24 September 2005 through 28 September 2005 ; Volume 1 A , 2005 , Pages 755-760 ; 0791847381 (ISBN) Durali, M ; Fathi, A ; Khajepour, A ; Toyserkani, E ; Sharif University of Technology

2005

Abstract

Laser Powder Deposition technique is an advanced production method with many applications. Despite this fact, reliable and accurate control schemes have not yet fully developed for this method. This article presents method for in time identification of the process for modeling and adaptation of proper control strategy. ARMAX structure is chosen for system model. Recursive least square method and Kalman Filter methods are adopted for system identification, and their performance are compared. Experimental data was used for system identification, and proper filtering schemes are devised here for noise elimination and increased estimation results. It was concluded that although both methods...

Genco's Bidding Strategy in Day-Ahead Energy Market Considering Demand Response

, M.Sc. Thesis Sharif University of Technology Kazemi, Mostafa (Author) ; Ehsan, Mehdi (Supervisor)

Abstract

Since 1980s the electricity market has been gradually evolving from a monopoly market into a liberalized one for encouraging competition and improving efficiency. This brings the opportunity for generation companies (Gencos) to make more proﬁts while embracing more risks of not being dispatched. Therefore, it has become a core interest for the Gencos to develop optimal bidding strategies to maximize the proﬁts and minimize the risks while participating in such a competitive market. Error of determining day-ahead electricity price is one of the sources of the risk. Energy price has a high impact on bidding strategy optimization process. So it should be determined with low error which is not...

Multi Objective Distributed Generation Planning in a Flexible Environment

, Ph.D. Dissertation Sharif University of Technology Soroudi, Alireza (Author) ; Ehsan, Mehdi (Supervisor)

Abstract

The process of deregulation that has involved electricity many markets has introduced several new interesting research topics in power system area. This thesis addresses one of the most fascinating issues among them: the study of distributed generation both renewable and conventional integration in distribution networks. From the distribution network operator (DNO)'s point of view, it is of interest to develop a comprehensive methodology which considers various distributed generation technologies as an option for supplying the demand in distribution networks. In this thesis, the planning problem has been multi-objectively modeled. This will help the planner in decision making while knowing...

, M.Sc. Thesis Sharif University of Technology Mahmoodzadeh, Zahra (Author) ; Ehsan, Mehdi (Supervisor)

Abstract

Losses are unavoidable in any parts of power systems, from generation to receiving nodes and occur in transmission and distribution networks. However, the main loss component is produced in distribution networks. Energy losses in distribution networks are about 70% of technological transport energy losses.
Energy losses in distribution networks are an important indicator for the planning and operation of the system. A fast, reliable and accurate energy loss calculation method is required for optimal operation of the distribution networks.
Energy loss depends on network's operating conditions. Loads values and loads factors are time variables; therefore, methods based on probability...

Methods of Clearing Reactive Power Market and Cost Allocation in Pool Structure

, M.Sc. Thesis Sharif University of Technology Kharraty, Saeed (Author) ; Ehsan, Mehdi (Supervisor)

Abstract

Restructuring and privatization in power system such as any industry leads to better market operation and more social welfare. Since two decade the power system in many countries have changed from monopoly to free market. In a restructured network the technical and economical aspects should be considered together. Ancillary services are needed for any power system to be operated in an optimal and secure manner. Reactive power and voltage regulation is one of the most important ancillary services in the network. this service should be supplied by its providers through a competitive market and system operator determines the optimal dispatch among different bids. The cost of purchasing reactive...

Dynamic Security Assessment in Restructured Power Systems

, Ph.D. Dissertation Sharif University of Technology Kheradmandi, Morteza (Author) ; Ehsan, Mahdi (Supervisor)

Abstract

This thesis addresses the problem of dynamic security assessment in power sys-tems with an emphasis on its application in restructured power systems and issues arising in its applications. The new electric utility environment has an immedi-ate consequence of emphasis on reliability and secure operation of power systems. This requires faster and more precise methods to assess the dynamic aspect of se-curity. On the other hand, this issue is becoming challenging when the determined dispatch might not be accommodated due to violation of the limits.This thesis addresses the problem of dynamic security assessment in power sys-tems with an emphasis on its application in restructured power systems...

Optimal Sizing and Operation of CHP Based on Stochastic Programming

, M.Sc. Thesis Sharif University of Technology Bozorg, Mokhtar (Author) ; Ehsan, Mehdi (Supervisor)

Abstract

CHP (Combined Heat and Power) generates electricity and thermal energy simultaneously from input fuel. Since it has high energy efficiency and low installation time, it is an appropriate approach in energy management of residential complexes. In this project, stochastic programming based on Monte Carlo approach is used to handle uncertainties in the optimal sizing of CHP for residential complexes. Availability of CHP, boiler and AC bus as well as the electrical and thermal load forecast errors are considered as stochastic variables. Minimizing system total cost considering the probability of each scenario obtained from the scenario reduction algorithm is the objective function. The system...

Planning of Energy Storage Systems with the Main Goal of Managing the Output Power of Wind Farms

, M.Sc. Thesis Sharif University of Technology Saber, Hossein (Author) ; Ehsan , Mehdi (Supervisor)

Abstract

Uncertain fuel prices and also global climate changes are accompanied by some state initiatives such as renewable portfolio standards (RPS). This has caused a fast growth in the amount of renewable energy installed worldwide especially wind energy over last decades. However, the intrinsic characteristics of wind farms output power, i.e. intermittency and volatility of wind speed along with being non-dispatchable in output generation of wind turbine raises many new technical and financial challenges for power system operators and planners. Up to these issues, large level of wind power penetration causes a growing concern in wind energy curtailment issue which the wind farm’s operator may be...

Retailer’s Medium-term Planning in Distribution Network Considering Uncertainty and Competitive Enviroment

, Ph.D. Dissertation Sharif University of Technology Kharrati, Saeed (Author) ; Ehsan , Mehdi (Supervisor)

Abstract

Electricity retailers are one of the power market entities which act as an intermediary between the producers in the wholesale market and the consumers in the retail side. The main task of a retailer in the power market is to set contract with the consumers to supply their electricity during a pre-specified time period and to participate in the wholesale market to supply the electricity needed by its costomers. Retailer’s contract with its customers may be a simple contract with a fixed pre-determined energy price or include some more complicated feathures such as involvement of a percent of green energy or variable price and demand response contracts. Moreover, retailer can supply its...

Scheduling of Retailers Performance in Electrical Energy Markets with Energy Production;Sell in Pool Market; and Demand Response Policies

, M.Sc. Thesis Sharif University of Technology Gilasi, Yasin (Author) ; Ehsan, Mehdy (Supervisor)

Abstract

Recent years of capitalism bold role and the competitive environment of variant fields of our life, sparking the idea which considers the electricity (one of the most crucial human requirement) as a commodity of a competitive market to be traded between confident subscribers by easy access. Therefore, by converting the exclusive structure of electricity supply system to a competitive one, some new roles are created to fulfill the electricity generation, transmission and distribution processes. Retail is one of the new roles, defined as a power system restructuring development helper by support of electricity trading, which can be involved in different transactions according to the market...

Linked Planning of Power Grids and Subsidy Policies on Using Photovoltaic Cells for Residential Electricity Supply

, M.Sc. Thesis Sharif University of Technology Balmaki, Saeed (Author) ; Ehsan, Mehdi (Supervisor)

Abstract

In recent years, due to restructuring in the electric power industry, distributed generation has become one of the most important subjects and DGs and renewable energy sources have been increasingly expected as a supplement and an alternative to a conventional large scale central power system. their success depends not only on the distribution of the available renewable energy sources in a region but also on the power grids connectable capacity in the area. Photovoltaic system is one of the best RESs for residential electricity supply because it is noiseless and solar power is widely available and households can use it via photovoltaic cells in their homes. There are two major problems...

Bidding and Offering Strategy of Hybrid Electric Companies in Day-ahead Energy Market

, Ph.D. Dissertation Sharif University of Technology Kazemi, Mostafa (Author) ; Ehsan, Mehdi (Supervisor)

Abstract

This Thesis presents a new approach for determining the day-ahead bidding strategies of a hybrid electric energy company. The company has both energy generation and energy retailing businesses in a competitive electricity market. Demand response programs are also considered in the retail side of the company in order to hedge the risk of participation in wholesale market. Price-taker and price maker companies are considered in this thesis separateky.For the price-taker hybrid structure, the predivtion of day-ahead prices are used to evaluate the optimum bidding and offering strategies. Also, day-ahead market price uncertainty is modeled, using non-probabilistic Information Gap Decision Theory...

Security Constrained Unit Commitment With Natural Gas Transmission Delivery Constraints

, M.Sc. Thesis Sharif University of Technology Badakhshan, Sobhan (Author) ; Ehsan, Mahdi (Supervisor)

Abstract

Natural gas power plant installed in power system as rapid start unit. In the recent decades, with increasing in the number of gas generating units in the world, consideration of natural gas transmission network in optimal solution of security-constrained unit commitment (SCUC) become a non-negligible problem. The gas transmission grid constraints integrated into the scheduling of thermal units in the proposed model for minimizes power system operating cost. In a power plant transmission of natural gas to power plant is very important because congestion in natural gas pipeline increases. This model could consider natural gas storage tank in gas transmission network as decision variable....

Distributed Generation Planning in Deregulated Electric Industry Using Multi-objective Optimization

, M.Sc. Thesis Sharif University of Technology Ahmadi, Mohammad (Author) ; Ehsan, Mehdi (Supervisor)

Expansion Planning of Active Distribution Networks in the Gradual PV
Increase

, M.Sc. Thesis Sharif University of Technology Khorshidi, Saman (Author) ; Ehsan, Mehdi (Supervisor)

Abstract

Due to the increasing influence of distribution generation , their effect in planning can't be ignord , especially solar panels ,which are incresing rapidly. The main purpose of this thesis is to an active distribution network that annually load bus and the amount of photovoltaic production in it increases and plan dynamically. In the planning that is done , uncertanty in the amount comsumption load and uncertanty in the pattern of sunlight and also annual innterest rates in the classical system we have planned by optimizing the network expansion costs , in addition to supplying the load bus, we can keep the voltage drop bus and line filling within the allowable . To do this , we considered...

Provisional Hybrid AC/DC Microgrid Planning

, M.Sc. Thesis Sharif University of Technology Mirzapour, Omid (Author) ; Ehsan, Mehdi (Supervisor)

Abstract

Renewable energy deployment through distributed energy resources is among the central goals of future power systems. Microgrids have proven to be an economically viable soloution for distributed energy resources integration into power system and benefit the customers with uninterrupted power supply. In this context provisional microgrids have been introduced with the main goal of rapid renewable energy sources deployment. Since a considerable portion of renewable enegy resources as well as residential loads are DC and this portion is expected to grow even further, hybrid AC/DC design of provisional microgrids can improve both efficiency and economic benefit by optimal arrangement of AC/DC...