Sharif Digital Repository

Titania is one of the photocatalytic materials , but low quantum yield and relatively high band gap of TiO2 limited its applications.There are several ways to improve the photocatalytic properties of this material relied on narrowing the band gap,by doping TiO2 with other metals and oxides or increasing its specific surface area.In this work ,TiO2-SiO2-Ni coating have been made by sol-gel process and deposited on quartz substrate by using of dip-coating method .Effect of increasing Nickel content in nanocomposite and primary sol on crystalline structure,morphol ogy, photocatalytic properties and specific surface area have been investigated by means of X-Ray diffraction method, FT-IR, SEM,... 

Airline scheduling is a dynamic process in nature such that it changes not only during one year period but also in smaller intervals due to the economic, political, religious, and social factors. Basically, airlines schedule planners through using mathematical models decide which flights are to be served in what periods of time and at what costs. This has to be done considering a set of constraints of different nature, from airspace and airport congestion up to climatic conditions or even crews working conditions. Such a complex problem requires different methods for an efficient solution. In this study by using network optimization method and applying different operational constraints on... 

Increasing global final energy demand and the use of fossil fuels to meet this amount of energy demand have raised concerns about environmental impacts of fossil fuel consumption and the reduction of fossil energy reserves. Among the energy consumer sectors including industry, transport activities, agriculture, and households, the household sector is one of the most important sectors, regarding its share of total final energy consumption. Heating and cooling systems, which mainly use fossil fuels, are the biggest energy consumers in the household sector. Hence, optimal management of the heating and cooling systems can play an effective role in reducing energy costs in buildings. In this... 

Liquid jet behavior in an intense electric field is studied experimentally and numerically.Imaging is used in experiments to charactrize jet behavior. Electrospray of ethanol using a simple needle in a wide range of operating conditions is investigated. Liquid meniscus is captured using a high-speed camera and different electrospray modes are described based on involved forces. A new nozzle is invented that broadens the stability margins of the useful cone-jet mode. The physical mechanisms of the new cone-jet is discussed and it is characterized using appropriate dimensionless parameters. A simple jet in presence of a gaseous crossflow and a normal electric field is also studied. The liquid... 

In recent decades, employing composite has growing field in various industries due to distinct features like high specific stiffness and strength. Functionally graded materials are clasified as inhomogeneous composite materials. Nowadays many researchers are investigating the behaviors of plates, shells and beam liked structures made of FGMs. In this project the dynamic behaviors of a FGM simply supported beam under a moving oscillator are studied. The beam properties are assumed to be varied through the thickness following a simple power law distribution. The system of equations of motion is derived by using Hamilton’s principle under the assumptions of the Euler–Bernoulli beam theory.... 

Sensitive ecosystem and scarcity of freshwater are the main characteristics of small islands. These islands have small catchments and usually lack tangible surface water resources. As a result these islands are dependent almost entirely on groundwater. Groundwater on small islands usually occurs in the form of a freshwater lens floating on the more dense saline water. The freshwater lens is highly sensitive to various stresses such as drought, pumping, sea tide, etc. Due to the importance of freshwater lens in islands, proper and optimal use of this vital resource should be studied. Kish island`s freshwater lens was three dimensionally simulated using the numerical model SUTRA. The aim was... 

In this study solid lubricants MoS2 nanoparticles with average size 50 nm and hard ZrO2 nanoparticles with average size 51 nm were used in watts bath and Ni/ZrO2-MoS2 composite coatings were prepared by pulse plating technique. Effect of current density, frequency, duty cycle, surfactant type and concentration of particles in the electrolyte on the amount of particles in the coatings were investigated and optimum conditions were determined to create composite coatings. Scanning Electron Microscopy (SEM) and x-ray diffraction (XRD) analysis were performed to study the morphology, structure, chemical composition of coatings. Corrosion testing of coatings by potentiodynamic polarization in... 

Groundwater is the primary source of freshwater in many coastal areas and small islands around the world. The most important hazard to groundwater quality in coastal aquifers is seawater intrusion (SWI) resulting from over pumping, prolonged drought conditions and sea level rise due to climate change impacts. Numerical models of SWI are an important tool in the management of coastal aquifers. However, numerical modeling of SWI is one of the most challenging problems in groundwater hydrology. One of the reasons for the challenging nature of SWI numerical modeling is the relatively large level of uncertainty associated with the estimation of the model input parameters. This study focused on... 

In this thesis, we investigate some problems in Sublinear field. We designed an algorithm that approximate the minimum distance of a shape to be a disk. In the first algorithm, we assumed that its input is a matrix and 1s in the matrix represent black pixels and 0s in the matrix represent white pixels. Also, we designed another algorithm that its input is a data structure contains the positions of a convex shape and we can sample uniformly from its pixels. In this problem similar to the first problem we must approximate the minimum distance of a shape to be a disk. Finally, we designed an algorithm for counting disks in a matrix. The input is a matrix that it contains some disks which have... 

In this thesis, the problem of building energy prediction modeling is investigated using system identification method. Since system identification method has lower error and high accuracy than other methods of building energy prediction. This method was used to model the energy prediction of the building of the Faculty of Energy Engineering.In this method, the different thermal areas of the building are divided into two groups: central and surrounding areas for modeling purposes. The sunscreens are not used in the model but are added to other system inputs in the thermal areas around these two inlets.Given that it is difficult to obtain planning for the presence of persons and the use of... 

Considering the widespread applications of α-aminonitriles, their synthesis is of great importance. The Strecker reaction represents a direct and appealing approach for the preparation of α-aminonitriles. With the aim of developing a mild and convenient approach towards the construction of α-aminonitriles, numerous methods have been reported for this important process over the past few decades. These have been mostly related to the optimization of reaction conditions and the use of more challenging substrates including ketimines and ketiminium salts and design of novel and effective catalytic systems. Due to the various advantages of supported heterogeneous catalysts and in our aim to... 

Considering the advantages of heterogeneous catalysts for the easy work up procedure, being eco-friendly, and the reusability, herein, two projects are carried out by metal-supported SBA-15 catalysts. The first one is the oxidative deprotection of trimethylsilyl ethers catalyzed Cr (VI) in the presence of TBHP as oxidant. In this project, trimethylsylil ethers are oxidized in good to high yields. The second project is the oxidative coupling of thiols to disulfides catalyzed by Fe (III) in the presence of hydrogenperoxide. This catalyst/oxidant system convets different aromatic thiols to corresponding disulfides efficiently  

The ever-growing demand for energy has raised concerns on sustainability of energy supplies and their environmental impact. Energy efficiency in buildings has gained special interest due to its energy consumption share in national scale. One of the most promising approaches for reducing building’s energy consumption is using an intelligent building management system (BMS). These systems have proved to reduce energy consumption while increasing comfort, and hence have gained global, and more recently national, recognition. This research has been devoted to the development of an intelligent building management system for the building of Sharif Energy Research Institute (SERI). The proposed... 

Providing fresh water, ending fossil fuels, using renewable energy and achieving a clean biological environment in different parts of the world especially in Iran beside having access to many saline water sources, Shows the need for research in the field of solar still desalination. The goal of current study is to increase the performance of the solar still system through the use of an energy storage system and an additional condenser. Adding an additional condenser to a conventional solar still lead to an increase in the rate of evaporation and consequently increase the production of the system. Also, by collecting distilled water from the sidewalls, the amount of water produced... 

Available Transmission Capability (ATC) is a measure of remaining capability in the transmission system for future use which is calculated and posted by Independent System Operator (ISO) considering various certain and uncertain power system parameters. ATC can be affected considerably by application of flexible AC transmission system (FACTS) controller among them Unified Power Flow Controller (UPFC) is the most recent one applied in power systems. This thesis is aimed to study the probabilistic ATC assessment incorporating UPFC. It first proposes a probabilistic ATC calculation method which is capable of considering various certain and uncertain parameters of ATC calculation in the... 

Many of today’s energy infrastructures need to be restructured to accompany the changes in the needs of humankind. On the one hand, more human activitie’s dependency on different energy carriers, and on the other hand, reduction of fossil fuels as the main energy resources, have caused that policies in many countries to be faced with fundamental changes in the area of energy. Optimal use of different types of energy carriers as an integrated system, is one of the main strategies that have been proposed to enhance energy efficiency. Using the concept of energy hub as the main key of integrated energy systems, this project intends to design a general framework for optimization and management... 

The present work has proposed an integrated methodology for combined gas & electricity distribution network expansion planning, which considers network expansion constraints (substation installation, feeder/pipeline installation, etc), load growth, and conversion technologies. The planning aims to determine the optimal reinforcement of existing energy network to meet the load growth in the planning horizon. To take the advantages of new technologies, CHP, fuel cell, & microturbine have been included in the problem.This paper employs gravitational search algorithm (GSA) to solve multi-objective problem, including minimization of cost, voltage drop, & pressure drop. GSA that introduced in... 

Optimizing and reducing energy consumption will be a feature of smart cities in the future. In addition to the technical aspects of a technology, one of the most important obstacles to its lack of development is not considering economic factors. Investigating the economics and calculating the cost of using IoT systems in the energy sectors of a smart city is one of the most important issues. Using existing systems in buildings or adding limited and inexpensive hardware to make a building smart can make smartening a cost-effective operation and more widespread. In this research, a proposed architecture based on edge processing is described. In addition to receiving and displaying camera... 

Compression systems are widely used in industry. Dynamic Modeling is a necessary step in design procedure of a safe compression system. A dynamic model should be adequate and simulate dominant elements of system. One important element of industrial compression systems is downstream pipelines. In this work, a dynamic model including pipeline acoustics is developed. It is accepted that changes of working gas molecular weight can cause inception of instabilities in compression systems. The dynamic model used to study mechanisms of these instabilities. A conventional control system is modeled and tuned for the compression system. The ability of this control system to prevent such instabilities...