Sharif Digital Repository

In recent years, various studies have been conducted focusing on the optimization and scheduling of energy hubs (EH). EH optimization is important because it tries to create synergy in the energy supply system by considering the relationships between energy carriers. For this purpose, various algorithms such as analytical methods (linear programming) and evolutionary and heuristic algorithms have been used. Also, recently, various studies have addressed the applications of reinforcement learning for energy hub management. In this study, a hybrid model for energy hub management has been developed by combining classical linear models (Known as white-box models) and reinforcement learning... 

The purpose of this study was aimed to evaluate the effect of Alumina on the sintering, phase development, mechanical properties and biocompatibility of fluoridated hyroxyapatite sintered via conventional furnace and microwave assisted oven. Green compacts having 30wt% Alumina nanoparticles were sintered without pressure at various temperatures (1000-1400°C) for one hour in conventional furnace. Phase composition, thermal behavior and morphological analyses were performed using X-ray diffraction (XRD), simultaneous thermogravimetry and differential thermal analysis (STA), and Scanning Electron Microscopy (SEM), respectively. With the increase in temperature and the Alumina content, severe... 

Regarding the ever-increasing usage of text generation and analysis in Natural Language Processing field, Language Modeling and Masked Language Modeling have been recently one of the most frequent tasks. Besides, many pretrained models such as BERT have been proposed due to the lack of rich datasets and computational resources among researchers. These models can be finetuned on other datasets in downstream tasks. Although these Transformer-based deep neural networks have performed perfectly in many problems, they still have some shortcomings in a few tasks.Furthermore, structured data like graphs have been recently used extensively in Natural Language Processing and researchers have taken... 

In the contemporary world, especially after the financial crisis, the importance of financial flow and working capital management for companies has become more important than ever. There have been various ways to meet the financial needs of companies in the past. Financing methods such as giving capital from investors and receiving loan, from the past, to new methods such as supply chain financing, which have been the major part of financing researches since 2005.Conversely, companies interact together to meet the needs of end customers and thus form a supply chain in which the product / service of each company, input and raw material of the company Forms the next. This chain of... 

Magnesium is one of most important elements in bio hedroxyapatite. Magnesium effects on all stages of bone growth metabolism. Also increases bone’s osteoblastic and osteoclastic activities. That’s why incorporation of Mg ions into hudroxyapatite structure has become one of interesting fields for bone implants production. In addition Mg can improve sintering and mechanical properties of HAp. Thet’s why in this investigation the effect of incorporated Mg into HAp structure has been studied. Three kinds of powders have been prepared to perform this study. Pure HAp nano powder produced via sol-gel method, Mg contain HAp nano powder produced via sol-gel method and a mixture of nano HAp and nano... 

Due to the presence of carbon dioxide and hydrogen sulfide in natural gas outlet of wells, it cannot be sent directly to the municipal pipelines. This study was trying to be select and made membranes for separation of CO2 and H2S from methane. Permeability of methane and carbon dioxide gases through the polyurethane membranes were studied. For this purpose, two commercial polyurethane and synthesized polyurethane with different formulations of the compounds that have been studied so far in the literature were used. Synthesized polyurethane and nano-composite membranes were characterized by using Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC) and Fourier Transfer... 

One of the important questions in mathematics is generalized. In case of metric spaces, one of the questions is: Can we extend notions of Riemannian geometry to arbitrary metric spaces smoothly? Ricci curvature is one of the most important concepts in differential geometry. Ricci curvature is defined for the Riemannian manifold and has many applications in mathematics and physics like Einstein’s equation in relativity theory. There is a good notion for a metric space having “sectional curvature bounded below by K” or “sectional curvature bounded above by K”, due to Alexandrov. Can we define the concept of Ricci curvature in metric space? A motivation for this question comes from Gromov’s... 

Seismic design codes reduce loads by using response modification factor. Because of the reserved strength in structural elements and capacity of structure to dissipate energy, structures can be designed for lower seismic loads. This factor has modified over time. In this thesis, the effect of the reduction in behavior factor on the response of two kinds of reinforced concrete systems were evaluated. Moment resisting frames and dual systems with different heights and regularity in plan, heve been design according to the behavior factor which is recommended in the 3rd edition of the Iranian codes of practice for seismic resistance design of buildings (Standard No. 2800). Drift and... 

Generally, nowadays, machine learning methods are used in many different areas for their superiority over other methods of prediction. Although being a tough task, stock market prediction with machine learning approaches is being spread due to satisfying results published ever yday. Machine learning methods usually use varied kinds of data ,including structured data such as market data, technical indicators and some fundamental data as well as unstructured one entailing text and graph data in order to enhance their predictability capacity. In this thesis we aimed to find out more about the importance and the contribution of structured data in prediction and we tried to attain a framework... 

This thesis presents an inventory control system which is based on Meta-heuristic Algorithms.In this thesis we will optimize the input values of our tree-echelon inventory model (keeping costs,stock worth,reorder costs,...) with these Algorithms. The presented method is able to determine the optimal stock level, costs of system and number of shipments in the system. The method is basically a decision support system (DES) and it is able to provide the order scheduling parameters of goods at operational level. The aim of the current research is to demonstrate that a Meta-heuristic algorithmis capable of solving complex inventory problems and with future improvements it is able to achieve... 

Reinforced concrete bridge columns located in regions of high seismicity are designed with large ductility capacity for adequate protection against collapse. This type of design tends to result in large permanent displacements. To maximize post-event operability and to minimize repair costs, new design strategies to reduce these residual displacements are necessary. Even though seismic codes ensure life safety for bridges, large residual displacement after severe earthquake may make the bridge useless. For example, after 1995 Hyogo-ken Nanbu earthquake (Japan), more than 100 reinforced concrete bridge columns experienced a tilt angle of more than 1 degree (1.75% drift). These columns had to... 

The new lateral load resisting system introduced in this dissertation is a kind of squat composite shear wall consisting of a concrete core as filler and two steel corrugated sheets as cover. Reinforced bars are not used in this kind of construction. Load resisting process of the walls is provided by 3 factors: concrete core, steel corrugated covers on both sides of the central core and shear-friction interaction between the core and covers. There is not any specific formula for their design because of their novelty and few researches on this kind of walls and absence of code provisions. In this project, squat composite walls were constructed with dimensions of 106.8×90 (cm2) from corrugated... 

One of the most important parts of a cement factory is the cement rotary kiln which plays a key role in quality and quantity of produced cement. In this part, the physical exertion and bilateral movement of air and materials, together with chemical reactions take place. Thus, this system has immensely complex and nonlinear dynamic equations. These equations have not worked out yet. Only in exceptional case; however, a large number of the involved parameters were crossed out and an approximation model was presented instead. This issue caused many problems for designing a cement rotary kiln controller. In this thesis, we employed a nonlinear system identification method for identification,... 

Because of absence of adequate studies, design of deep beams with web openings has not yet been covered by most codes of practice. The most studies have been on simply supported deep beams with web openings and have been set up experimentally. There are very few tests of continuous deep beams available in the literature. So it was decided in this thesis the behaviour of concrete continuous deep beams with web openings using finite element software ANSYS to be investigated. Primary purpose of this thesis has been evaluating the use of finite element analysis method for analysis of concrete continuous deep beams with web openings. The next target of this thesis has been assessment of... 

Acidity values of some compound (e.g., alkanes, alcohols, carboxylic acids and amines) with or without boron substitute have been studied theoretically to evaluate the influence of boron on acidity of organic functional groups. We have derived the unoccupied reactive orbital that show the maximum localization on the boron pπ atomic orbital overlapping with the lone-pair orbital of an electron donor. Localization of unoccupied reactive orbital on the boron pπ atomic and the polarizability of the boron center are two factors which affect acidity values of functional groups. Conformational searching was performed using MM (Molecular Mechanics). The most important conformations were optimized at... 

Poincare conjecture is one of the rst eorts for classifying 3-manifolds that was stated in the begining of 20th century. Eorts for proving this conjecture continued for about 100 years and nally Perelman has solved it in 2003. He has used Ricci ow which has been invented by Richard Hamilton in the early 80's. In this thesis rst we will introduce Ricci ow and will state the results before Perelman such as short time and long time existence of solution. Then we will mention some applications of Ricci ow and will state an explanation of the proof of uniformization and Calabi conjecture by Ricci ow. After that we start the main part of the thesis. In this part we will montion one of the...