Sharif Digital Repository

Nowadays, with the increasing need to design and manufacture parts with dimensions less than 1 millimeter in various fields such as medicine, drug delivery, microfluidics, precision casting, and many other areas, methods for manufacturing such parts have gained significant attention. Numerous studies have been conducted to develop 3D printing methods for manufacturing increasingly smaller parts, with optical 3D printing research being at the forefront. In this regard, researchers have enabled the achievement of smaller parts by developing in three areas: increasing the resolution of the light source, changing the resin compositions, and improving the accuracy and correction of image pixels.... 

The purpose of this study is to solve the problem of allocating relief teams to reopen damaged roads and remove debris from damaged areas after the earthquake for large cities. In the deteriorated areas of large metropolises, severe earthquakes may damage links, which causes some nodes to separate from the network. In this research, by using an Ant System meta-heuristic algorithm, a joint problem of damaged link restoration and demolished zone debries removal problem for search and rescue of the trapped population in an earthquake is solved. Ant System parameters are calibrated, and sensitivity analyses are done for the number of relief teams, earthquake intensity. The results of 1000... 

With the rapid increase of energy consumption, energy problem has been a global issue, which must be faced with and solved. One way to prevent energy consumption is to reduce drag in the flow inside the pipes by using polymer additives; Because the Transportation of liquids using pipeline technology has its limitations, since turbulent flow inside the pipe involves a loss of energy. The net effect of this is that increasing the energy applied to the flow does not increase the flow rate. For this purpose, copolymers and terpolymers of hydrophilic acrylamide monomers along with hydrophobic styrene and hydrophilic maleic anhydride monomers were synthesized by reverse emulsion polymerization... 

Studying the performance of flow meters is of great importance in order to improve their quality. In this study, we are looking for an optimal design for a turbine flow meter in which the measurement accuracy, pressure drop and response speed indices are improved. For this purpose, a turbine flow meter with a diameter of 2 inches has been selected and its performance has been numerically modeled using computational fluid dynamics in a steady and transient state. By modeling the steady state, the measurement accuracy and pressure drop indices are obtained, and by modeling the transient state, the response time of the flow meter is obtained. In order to increase the accuracy of numerical... 

In this work a new innovative microfluidic system for the selection of motile sperms was developed. The novel aspect of this work is based on the fact the motile sperms follow microchannel walls. Immotile sperms are not able to follow curved paths and therefore their movement toward the outlet gets hindered and most of them could not reach to the outlet. But motile sperms, moving alongside the microchannel walls, reach to the outlet and get separated from the immotile ones. After designing, 3 microfluidic chips having curved microchannels with curvature radius of 150, 300 and 600 micrometer and one with a straight microchannel were fabricated using photolithography and soft lithography.... 

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... 

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... 

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... 

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... 

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... 

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... 

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... 

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... 

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... 

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... 

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... 

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.... 

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...