Sharif Digital Repository

One of the topics that has been given great consideration after restructuring and smart grid emergence, is loss management. This subject is specifically important in distribution systems, which have been reported to have 70% of the total loss in power systems. In this thesis, distribution loss is studied and its affecting factors are analyzed. Then loss optimization and loss cost allocation to distribution consumers are studeid. In order to acheive these two goals, it is neccessary for the distribution system to have the capabilities of a smart grid. The subjectof distribution reconfiguration is duiscussed as one of the loss reduction methods. Traditional reconfiguration problem trend... 

The primary objective of this thesis is to provide solutions addressing some security loopholes in continuous variables quantum key distribution protocols. The coherent detection method is utilized in this particular quantum key distribution scheme, which is a phase-sensitive detection. To measure in the quantum noise limit in the detection part, we need a local optical oscillator, which must possess a high intensity and a consistent phase correlation with the quantum signal. Therefore, reconstructing the emitter’s reference phase in the receiver’s detection system is considered as one of the most critical challenges in these protocols. In order to attain this goal, in the early versions of... 

In this thesis, we introduce a novel Artificial Intelligence (AI) system inspired by the philosophical and psychoanalytical concept of imagination as a ``Re-construction of Experiences". Our AI system is equipped with an imagination-inspired module that bridges the gap between textual inputs and other modalities, enriching the derived information based on previously learned experiences. A unique feature of our system is its ability to formulate independent perceptions of inputs. This leads to unique interpretations of a concept that may differ from human interpretations but are equally valid, a phenomenon we term as ``Interpretable Misunderstanding". We employ large-scale models,... 

According to today’s medicine progress, the need for improving the medical facilities have been increased. Within the human body, the biomolecules concentration gradient is regulating the cell functions. Biological processes such as immune response, wound healing, and cancer metastasis have been affected by the bimolecular concentration gradient. So understanding the cell behavior in the presence of a chemical gradient can improve the understanding from these biological processes, and also would help in medical researches. On the other hand, finding the appropriate dose of the drugs and in some cases finding the most effective drug is a clinical challenge that made a new field of research in... 

The development of clean, renewable and alternative sources of fossil fuels has increased in recent years due to various factors such as environmental pollution, reduced fossil fuel resources and increased energy consumption. The application of microbial fuel cells is one of the clean energy production methods using renewable sources such as municipal sewage. The microbial fuel cell converts the chemical energy stored in organic materials into electrical energy and simultaneously purifies the sewage. Increasing current density and power density are the most important challenges for microbial fuel cells. In this study, the two biocatalysts of Shewanella Oneidensis MR1 and Escherichia coli... 

Biotechnology is one of the fields that has had great advances in the past decades, and therefore controlling biological processes (bioreactors) is considered as an important issue. The purpose of current thesis is designing an adaptive controller for a bioreactor by considering input constrain and proving the stability of closed loop. A standard bioreactor has been chosen for this purpose. First a non-adaptive controller has been designed. Then an adaptive controller is designed and implemented on a bioreactor in the presence of input constraint, because in practice the system parameters are unknown. Finally by applying disturbance to the system, it has been shown that the proposed control... 

In the present study, for cost-effective brine elimination of desalination plants, a hybrid system consisting of a multiple-effect distillation unit and a humidification-dehumidification unit is proposed. The development process of the hybrid system was carried out in two main steps: 1) evaluation of electricity-driven and heat-driven humidification-dehumidification brine concentrators 2) redesigning the humidification-dehumidification unit according to the results of step one and hybridization the unit with a multiple-effect distillation system. All the steps are assessed using the energy, exergy, exergoeconomics, and exergoenvironmental tools.Among the three heat-driven and... 

During fuel combustion, aromatic sulfur compounds in energy fuels convert into sulfur oxides, which cause major environmental problems such as acidic rain, global warming, and air pollution. Absorption desulfurization is one of the promising and economical methods to remove these sulfur compounds from fuels. Metal-organic frameworks (MOFs) are a class of nanoporous materials that are of interest for use as adsorbents due to their high specific surface area, unique surface adsorption properties, high adsorption capacity, tunable porosity, flexible dynamic behavior, and diversity in functional and metal groups. In this research, we first synthesized five metal-organic frameworks, namely... 

In this research, molybdenum and tungsten catalysts modified with cobalt and nickel on a carbon support have been synthesized and investigated in the oxidation desulfurization process. A model fuel was used to evaluate the synthesized catalysts. This model fuel was n-decane. dibenzothiophene was also used as a sulfur model. The synthesized catalysts were subjected to various analyzes such as XRD, FTIR, Raman, BET-BJH, NH3-TPD, TEM and ICP-OES for structural evaluation. On the other hand, synthetic parameters such as metal loading rate, molar or weight ratio of secondary metal (cobalt and nickel) to primary metal (molybdenum and tungsten) and molar ratio of citric acid to primary metal as... 

Various factors, such as increasing or decreasing the heat removal from the initial circuit, or increasing the flow rate of the cooling fluid in the reactor, causes the phenomenon of the coolant mixing in the PWR reactors. In this project, the thermohydraulic test of coolant mixing has been simulated in the pressure vessel of the Bushehr nuclear reactor. In this test, the mixing of the coolant caused by the reduction of heat removal from the primary circuit by the secondary circuit is investigated. In this case, the primary circuit temperature increases in the loop where the heat removal is reduced. The most important consequence of this event is the reactivity changes at the core of the... 

In order to ensure the safety of the plants, a set of commissioning tests based on international standards for nuclear power plants is carried out before operation. In this research, one of the Bushehr power plant commissioning tests, the loop connection primary circuit cooling pump test, was simulated using the RELAP5 code. In this test, the effects of loop connection primary circuit pumps on the thermohydraulic parameters and the eneterance of test-related systems was evaluated. After simulating the systems related to the test and extracting the results of the stable state, were evaluated the transient results was obtained with the experimental results of the test of loop connection the...