Sharif Digital Repository

According to the unique characteristics and increased competition in Business-to-Business (B2B) exchanges, achieving customer loyalty is becoming more and more crucial in B2B marketing. Furthermore, with the advent of relationship marketing, it is important to sustain a long term relationship with customers.Thus, the major issue is to examine what influences a customer’s willingness to remain with the existing supplier. The purpose of this study is to identify the antecedents of customer loyalty in a Business-to-Business context. Based on the relevant literature on customer loyalty and satisfaction, a conceptual model is developed to assess the most influential drivers of loyalty. The... 

Most of dynamical models in the real world, have various restrictions and complexities in their structures. These constraints make the controller design much more difficult. In this work, it has been tried to design the controller for two kinds of common dynamical systems in the presence of these restriction by using the fuzzy logic systems. Several restrictions are investigated in this project such as unknown dynamic of the model, unmeasured state variables, unknown control directions, existence of time delay in the input and the state variables, input saturation and controller singularity.The backstepping technique and the dynamic surfaces control approach have been used to design the... 

Today, almost all the country's needs in the field of industrial enzymes are met through imports. In this regard, much attention has been paid to the industrial production of various enzymes in the country. The production of recombinant proteins through strain engineering is one of the most important ways to meet this demand due to its many benefits. One of the most important microorganisms that is widely used in the enzyme industry is Bacillus subtilis. Due to its thick peptidoglycan wall, this gram-positive bacterium hardly accepts engineered carriers for genetic modification as hosts. The aim of this study was to evaluate the permeability of the wall and cell membrane of Bacillus subtilis... 

One of the lesser-known issues in the modeling literature of assortment optimization issues is the assortment optimization for reusable products, which is an issue in various areas, including offering parking space, renting cloud computing systems resources, and rental of fashion products, etc.In this issue, we are faced with a high diversity product rental store that has a customer in each period. The seller offers a limited set of products depending on the customer demand and the inventory in hand. He can decide to rent the product or leave the system without renting the product. In case of renting the products by the customer, he may return them until the end of this period or keep them... 

The most common form of communication on the internet and social network websites is text messages. normally communication on social media or even on the web is by posting some sort of text. usually, these messages or posts are short and text used in them may not follow any language standards, this makes it very difficult to process them. Different age groups use a certain language differently and this is shown in the way, each of them writes texts. The advancements made in the field of natural language processing and computational linguistics makes it possible to predict, text authors age groups by analyzing the way they write. This study focuses on ways to automatically recognize the age... 

Histopathology images are a type of medical images that are used to diagnose a variety of diseases. One of these illnesses is the Leukemia cancer, which has four different subtypes and is diagnosed using a blood smear image. As a result of the advancement of deep learning tools, models for diagnosing various types of disease from images have been developed in recent years.In this project, one of the best models developed to diagnose four different types of disease was replicated, and it was demonstrated that, while this model achieves acceptable accuracy, its decision is not based on medically significant criteria. In the following, a general method for diagnosing the disease is proposed... 

Lithium is one of the most commonly used metals in industry with a wide variety of applications including batteries, lubricating grease and pharmaceutical products. Demand for lithium is expected to rise with the increasing adoption of electric vehicles. Market reports have predicted that world lithium demand will increase by 2.5 times from 2010 to 2020. Therefore, there is a pressing need to develop new sources of lithium to support this anticipated increase in demand. Lithium can be extracted from salt brine and lithium containing minerals as lithium compounds.
Salt brines are the most abundant lithium sources available in the world, comprising about 60% of all known lithium deposits.... 

As one of the most important agglomeration methods, pelletizing has a very important place in the iron and steel production chain. In the present study, the feasibility of improving FeO index in the final product of Pellet Factory No.1 of GolEGohar Mining and Industrial Company was investigated. The remaining FeO in the iron oxide pellet represents the amount of Magnetite that was not oxidized during the pelletizing process. The remaining FeO in the primary Magnetite is a disturbing structure for the direct reduction process and will cause a decrease in the compressive strength of the pellet (CCS) and as a result it will be crushed. Therefore, the percentage of the remaining FeO in the... 

This study presents an experimental and numerical investigation on the compressive behavior of a new type of composite column which consists of both solid and hollow concrete-filled UPVC tube with and without GFRP wraps.Composite construction has been often more economical than traditional concrete construction, because this system realizes the most effective use of concrete, and composite members in the structural system.The enormous potential of using plastic tubes in composite systems will be illustrated by this research. It is an economical type of column in construction.This research aims to study the behavior of UPVC-confined columns under axial compression. A sum of 132 specimens are... 

Supersonic inlets, as one of the most important components of fighter aircraft, are designed to provide the required airflow with an acceptable level of energy and quality and with a minimum drag. From the inlet design point of view, there exist various configurations that are based on different criterion such as supersonic flow compression region, flow dimensions, and installation position, to name a few. The flight Mach number, M∞, could further complicate the design and structure of these types of inlets. One of the requirements for minimum drag is that at supersonic speed the shock wave that forms in front of the inlet must impinge on the cowl lip, called shock on lip condition (SOL). ... 

This project discusses designing and implementing a model predictive controller for attitude control of a satellite with reaction wheels as actuator. Deriving a predictive model and designing the controller is performed based on linear model of rigid satellite attitude dynamics. The designed controller is utilized to control both a constrained and a nonlinear problem by using optimization method such as quadratic programming. The controller performance and its robustness, in case of uncertainties in model parameters and encountering external disturbances, are studied and compared with those sliding mode controller  

Zinc oxide thin films due to special specification and properties have variable application in different industries. Recently because of wide application of zinc oxide doped SiO2 in optoelectronics and sensors, lots of investigation have been focus on it. Meanwhile due to the SiO2 hydrophilic properties, doping of ZnO with SiO2 can improve self-cleaning properties zinc oxide membrane.It this project zinc oxide and ZnO doped SiO2 thin films with different composition were made by sol-gel and dip-coating process used for coating of mentioned sol over the quartz surface(15*25 mm). At first point different sol with different components was mixed with each other to make composite films but due to... 

Today a significant portion of the world magnesia supply is produced by approximately 20 manufacturers by precipitation of magnesium hydroxide either from seawater or brine sources, which amounts to about 14% of the world magnesia production. The first synthetic magnesia production occurred along the French coast of the Mediterranean Sea, near Aiques-Mortes, operating sometime before 1885. Magnesium hydroxide was precipitated from seawater by reacting it with milk of lime in a continuous fashion using three sequential agitated reactors. Because of the abundance of brine resources enrich in Magnesium in our country, in this project, was tried to precipitate Magnesium Hydroxide from brine... 

In the present project, in order to be self-sufficient and optimal use of boron mines in Iran, a study entitled “The effect of process variables on the production of boric acid” has been conducted, This project has two main objectives: the first objective is the production of boric acid from boron sources and mines in Iran and the second objective is to analyze the effect of variables such as temperature, time, acid concentration, solid to liquid ratio and particle size on the purity of boric acid produced. And finally achieve the optimal conditions for the production of boric acid.In this study, boric acid was made from leaching hydrobracite (magnesium-calcium ore with boron) with sulfuric... 

Combustion synthesis is the best and most effective method for producing ceramic nano-composites which is also a simple and economic way of producing very fine powders with high purity. In this method, a series of combustion reactions named aqueous combustion analysis are used for producing single-phase and nano-composite products ,in which the heat produced in reactions are used for completing the phase . several chemical substances such as glycine ,urea ,ammonium acetate and others are used as combustion agents. In order to obtain optimized nano fuel, we produced alumina powder with multiple combustion percentages and composition of 25%moli ammonium acetate (AA) with 75%moli urea was... 

Due to their low volatility, negligible flammability, and high regeneration capacity, ionic liquids have attracted a lot of attention in chemical and process engineering fields. Regarding the limited access to the laboratory facilities, developing theoretical methods such as equations of state is important in this research field. Thus, data for density and viscosity of pure ionic liquids and vapor pressure data for binary mixtures of ionic liquids and acidic gas have been collected and validated from the IL Thermo website for 42 ionic liquids. By consideration of theoretical studies and comparison of the performance of different cubic equations of state in predicting the aforementioned... 

In this work, polyvinylidene difluoride (PVDF) as a ferroelectric polymer, polyaniline (PANI) and polypyrrole (PPy) as conductive polymer additives are used to fabricate high performance mesoporous CH3NH3PbI3-xClx mixed-halide perovskite solar cells in a sequential deposition method. Using polymer additives in perovskite precursor solution leads to modification of perovskite layer morphology by changing nucleation and growth of perovskite grains. Besides, conductive polymer additives in perovskite layer help to more charge carrier transfer. Power conversion efficiency has been enhanced from 10.40 % to 16.51% and to 13.21 % in ambient atmosphere in the presence of 1.0 wt. % of PVDF and PPy... 

Today, due to limited number of light oil reservoirs, enhanced recovery from heavy oil reservoirs is taken into consideration. During the early production from heavy oil reservoirs, due to high viscosity, only a small amount (about 5%) of the oil can be produced; also after water injection operation due to unfavorable mobility ratio of water and oil, sorely more than about 10% of the original oil can be produced. On the other hand, fractured reservoirs represent about 20% of the world's oil reserves, while over 60% of the world's remaining oil reserves are in fractured reservoirs. Water flooding process leaves very high amounts of oil as remaining oil in these reservoirs too. One of the...