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mohammadi-dinani--ali
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An optimized economic-environmental model for a proposed flare gas recovery system
, Article Energy Reports ; Volume 9 , 2023 , Pages 2921-2934 ; 23524847 (ISSN) ; Nassaji, A ; Hamzehlouyan, T ; Sharif University of Technology
Elsevier Ltd
2023
Abstract
Iran is the second largest oil and gas producer among the Persian Gulf states, with 13.26 billion m3 gas flaring in 2020, approximately 9.34% of the global gas flaring. To reduce pollutants emissions and energy loss, an accurate feasibility study of flare gas recovery technologies is needed as the first step. Multi-objective optimization of process structure for the development of a comprehensive flare gas recovery system based on process simulation has not attracted much attention in the literature. In this study, a process structure for a flare gas recovery system was proposed using a multi-objective optimization approach to decrease associated gas flaring in southern Iran with a current...
Optimal Routing in Expansion Planning of Gas Transmission Networks Based on Economic, Operational and Resiliency Criteria
, M.Sc. Thesis Sharif University of Technology ; Bozorgmehry Boozarjomehry, Ramin (Supervisor)
Abstract
Gas transmission networks, as one of the most important energy transport networks, are used to transport gas from production facilities to major gas consumers. These networks possess very complex behavior due to their severely nonlinear equations, their temporal and spatial broadness, the compressibility feature of the fluid that passes through them, and their relationship and interdependency with other energy material generation, transportation, and distribution infrastructures through multi-vector energy systems. Hence, the management and coordination of these networks are challenging. In this regard, the most demanding problem of such networks is their expansion planning due to the...
Scene Detection and Analysis by Image Classification in Specific Classes
, M.Sc. Thesis Sharif University of Technology ; Gholampour, Iman (Supervisor)
Abstract
Traffic density estimation is one of the most challenging problems in Intelligent Transportation Systems. One of the important traffic information that is broadcasted to drivers is Traffic Density information. In many traffic control centers; human operators are responsible for estimating traffic density from captured video data. Increasing traffic cameras and constraint number of operators introduce an updating delay to broadcasted information. So it is important to have an automatic traffic density estimation system. In this thesis, machine vision is used to solve this problem. Supervised Image classification is our approach. In supervised Image classification, images are classified to...
Analysis of Reliability of High Power Amplifier
, M.Sc. Thesis Sharif University of Technology ; Medi, Ali (Supervisor)
Abstract
Nowadays, using of microwave integrated circuits in military and industry applications has been became popular, especially with the advent of monolithic microwave integrated circuits which provide possibility of fabrication of amplifiers in large volume with high precision and appropriate cost. Power amplifiers as the last block of transmitters, are such circuits that are too attractive in this area. Since high power amplifiers consume a lot of power in transistors, large amount of heat will be in the surface of chip. Loss of some of consumed power in amplifiers results increasing transistor’s channel and chip surface temperature. Increase in channel temperature results degradation in...
Numerical Investigation of Motion of Nanodroplets on Wetting Gradient Surfaces
, M.Sc. Thesis Sharif University of Technology ; Moosavi, Ali (Supervisor)
Abstract
A droplet placed on the boundary of two solids with different wettabilities will move to the more wettable part. This is a well-known phenomenon and has been extensively used in a variety of processes and applications ranging from biological systems and ink jet printing to the commercial lab-on-a-chip. Because of its importance, many studies are conducted around this phenomenon. The difference between the equilibrium contact angles of the droplet on the two parts gives rise to an interfacial driving force which moves the droplet. Such a motion is not continuous as the droplet slides to the more wettable area, the driving force diminishes and consequently the droplet stops. A non-stop motion...
Numerical Modeling of the Bahavior of Unsaturated Soils with the BBM in the FLAC Software
, M.Sc. Thesis Sharif University of Technology ; Pak, Ali (Supervisor)
Abstract
Although unsaturated soils exist all around the world, civil engineers are not familiar with unsaturated soil behavior; consequently, the soil structures they design may neither be safe nor economical. Thus, implementing unsaturated soil constitutive models to practical computer softwares can be very beneficial for geotechnical engineers. Geotechnical engineering softwares normally consider soil in saturated or dry conditions. So, their built-in constitutive models do not usually consider unsaturated soils. In this study, Barcelona Basic Model (BBM), which is developed using critical states soils mechanics principles, is implemented to the FLAC2D software. This model can simulate complex...
Identification and Attractiveness Assessment of Technologies Used in Aging Aircraft Life Extension
, M.Sc. Thesis Sharif University of Technology ; Abedian, Ali (Supervisor)
Abstract
Lifetime extension would be a necessary preventive action to halt micro cracks expansion on the airplane external surface. To decide about whether to perform this operation, one should examine technological maturity, costs and technical parameters. Technical status in lifetime extension is one of the major drivers of this decision which should be considered in the first step of technology management process which is known as the technology attractiveness step. In this research, major technologies of rejuvenation is examined and categorized by the technology mapping. Also, key processes of rejuvenation and technological fields ranking has been determined by the procedural view tools of the...
Studying the Effect of Carbon Nanotubes Addition on the Mechanical and Hydration Properties and Microstructure of Magnesia Doloma Refractories
,
M.Sc. Thesis
Sharif University of Technology
;
Nemati, Ali
(Supervisor)
Abstract
Magnesia-doloma refractories are alkaline products made by combining sintered or fused dolomite and magnesite. These refractories contain 50-80 wt% magnesium and a higher percentage of magnesium oxide, provides desirable properties such as improved refractoriness and resistance to air moisture absorption. Magnesia-doloma refractories have significant weaknesses, including rapid hydration due to the presence of CaO and MgO phases. These refractories are also primarily used with carbon additives in the industry, where increasing the carbon weight percentage in these refractories weakens their strength and some of mechanical properties. In the present study, the effect of adding carbon...
Efficient feature extraction for highway traffic density classification
, Article 9th Iranian Conference on Machine Vision and Image Processing, 18 November 2015 through 19 November 2015 ; Volume 2016-February , 2015 , Pages 14-19 ; 21666776 (ISSN) ; 9781467385398 (ISBN) ; Ahmadi, P ; Gholampour, I ; Sharif University of Technology
IEEE Computer Society
2015
Abstract
Traffic density estimation is one of the most challenging problems in Intelligent Transportation Systems. In this paper, we estimate the traffic flow density based on classification. Various new efficient features are introduced for distinguishing between different traffic states, including number of key-points, edges of difference-image and moving edges. These features describe the traffic flow without any need to individual vehicles detection and tracking. We experiment our proposed approach on a standard database and some real videos from Tehran roads. The results show high accuracy performance of our method, even in changes of environmental conditions (e.g., lighting), by using efficient...
Experimental and Theoretical Investigation on Losses and One Dimensional Modeling of The Centrifugal Compressor
, M.Sc. Thesis Sharif University of Technology ; Hajilouy Benisi, Ali (Supervisor)
Abstract
Centrifugal compressors have wide applications in the turbochargers, aircraft propulsion and petrochemical industry. Therefore it is important to design high efficiency centrifugal compressor. Knowledge of compressor performance at different conditions, energy losses and the contribution of each component of compressor in efficiency losses have of great importance.
In this research, different loss models of the centrifugal compressor were reviewed and investigated. Then 1D codes were developed based on the loss models, and performance characteristics of S2B Schweitzer and GT4082 Garret compressors at different conditions were achieved. In order to evaluate the modeling results,...
In this research, different loss models of the centrifugal compressor were reviewed and investigated. Then 1D codes were developed based on the loss models, and performance characteristics of S2B Schweitzer and GT4082 Garret compressors at different conditions were achieved. In order to evaluate the modeling results,...
Bromo-lithium Exchange Reaction in Organic Synthesis and Continuous Separation of Organic and Aqueous phase Reactions by Microfloid Technique
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Ali Asghar (Supervisor) ; Bastani, Dariush (Supervisor)
Abstract
Today, with the development of micro-technology in chemical reactions, the use of appropriate systems for the separation and purification of synthesized chemicals seems to be necessary. In this study, the continuous synthesis of bromide-lithium exchange reaction and the separation of organic and aqueous phase products in micro systems was investigated.The method used to construct micro-separator and micro reactor, a laser engraving technique, and thermal bonding of glass to glass.In the first step, the factors affecting the separation of organic and aqueous phase in the capillary micro-separator, such as the width of the capillary, the length of the capillary, the number of capillaries and...
Numerical-Analytical Modeling And Fabrication of A New Vehicle Cooling System Using Vapor-Jet Refrigeration Cycle
,
M.Sc. Thesis
Sharif University of Technology
;
Farhanieh, Bijan
(Supervisor)
Abstract
Today, the world energy crisis, the need to optimize its consumption and discussion to reduce fuel consumption has become a vital issue. The conventional vehicle air conditioning system due to compressor in refrigeration cycle, which has causes a severe loss in engine useful power, increasing fuel consumption, etc. Therefore, the main goal of this project is the feasibility of the vehicle cooler replacement with the vapor jet refrigeration cycle. In this cycle, the energy required for completing the refrigeration cycle is provided from the heat of the water inside the radiator that is possible with conventional refrigeration cycle. The first stage of this project includes design and...
Electric-field-induced Response of Charged Droplets in Uncharged Hydrogels
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Ali Asghar (Supervisor)
Abstract
The electric field induced response of a charged droplet in an uncharged gel is calculated theoretically. For modeling, the gel is considered as a soft porous solid that is saturated with a Newtonian electrolyte and modeled as a continuum that contains 3 phases: a porous, soft and compressible solid, an incompressible Newtonian fluid and the ions inside fluid. Droplet is modeled as a charged incompressible Newtonian fluid immiscible with the gel. The droplet-gel interface is considered as a surface with electrostatic potential ζ . After obtaining governing equations, they solved by using perturbation methodology and linear superposition. Boundary conditions, especially at the droplet-gel...
Janus Silica Nanoparticles and Their Application for Enhanced Oil Recovery
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Ali Asghar (Supervisor)
Abstract
Nanoparticles can be applied as chemical agent in enhnaced oil recovery like surfactants and polymers. One of nanoparticles usefull capabilities is modification of their surface. This research investigates this capabilty of nanoparticles in enhanced oil recovery. Surface modification of nanoparticles with both agents can bring new abilities to these materials. Here surface of silica nanoparticles is modified by hydrophilic agent comprising PEG groups, hydrophobic agent comprising propyl group and both agents. FT-IR tests showed that grafting of modifiyng agents on surface of nanoparticles is well done. To investigate effect of nanoparticles surface modification on nanoparticles capability in...
Synthesis of Amphiphilic Nanoparticles with Different Alkyl Chains and their Application in Enhanced Oil Recovery
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Ali Asghar (Supervisor)
Abstract
Important features of the nanoparticles properties are their high superficial area and being able to reform their surface. In this study, the repairable property used to reform surface of silica nanoparticles (Those are used more frequently than other nanoparticles). Repairing of surface are doing to use nanoparticles as a surface-active material in enhanced oil recovery. Silane compounds with different chain length are used to create hydrophobic nanoparticles and PEG compounds are used to create hydrophilic nanoparticles. Also amphiphilic nanoparticles are created with a combination of both hydrophilic and hydrophobic compounds. To investigate the usefulness of nanofluids are made up of the...
Design and Fabrication of a Microfluidic System Based on Dielectrophoresis for Enrichment and Separation of Bioparticles
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Ali Asghar (Supervisor)
Abstract
The main purposes of this project are simulation, design, and fabrication of a microfluidic system based on dielectrophoresis (DEP) exploiting AC voltages for separation of microparticles. Generally, this project can be divided into two parts. First, the engineering section including design and fabrication of microchip, and second biological samples preparation for investigating the system performance. The main advantages of proposed system are eliminating joule heating, a significant problem in insulating based dielectrophoresis systems, overcoming problems related to metal contamination in biological samples, the main problem of conventional dielectrophoresis platforms, and removing...
Investigation of the Effect of Combination of Severe Plastic Deformation (ECAP) and Shot Peening on Fatigue Properties of an Al-Mg-Si Alloy
, M.Sc. Thesis Sharif University of Technology ; Karimi Taheri, Ali (Supervisor)
Abstract
Production of nanocrystalline (under 100nm) or submicron materials (100-1000nm), has been created to one of the most important problems in engineering. A well-known method to create Ultra-Fined Grains (UFG) is imposing high strains to metals in order to break the structure. Among lots of ways forproducing UFG metals, Equal Channel Angular Pressing (ECAP) is one of the most famous and common ways. On the other hand, Shot Peening has been being used for a long time to improve mechanical properties of metals by introducing nanocrystalline layer at the surface of specimen. The aim of the work, is investigation of the effect of combination of ECAP and Shot Peening on High Cycle Fatigue of 6082...
Analytical and Experimental Study of Isolation of Sensitive Equipments from Ambient Vibrations
, M.Sc. Thesis Sharif University of Technology ; Bakhshi, Ali (Supervisor)
Abstract
In some activities, an almost free of any vibration environment is needed. Semi conductor production process and microelectronic microscopes are two examples in which a quiet environment is essential. The goal of this thesis is to attenuate ambient vibrations effectively and to prepare a suitable environment for two microelectronic microscopes. The designed system must be practical, economical and capable of being made in a short time interval. Considering mentioned properties a steel table with bolt connections supported on 4 air springs was built. To investigate dynamic properties, modal analysis was performed with the aid of finite element packages and experiments. To extract oscillations...
Simulating of Droplet Formation and Calculation of Interfacial Tension by Microfluidic Method
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Ali Asghar (Supervisor)
Abstract
Emulsions are the intermittent dispersion of liquid droplets that have many applications such as polymerization, dyeing, cosmetics, food industry, etc. Droplets can be created in a variety of ways, but the most important point in emulsification and the greatest efficiency of its applications is when the formed droplets are uniform. In the emulsification process, there is a key parameter called interfacial tension, which affects the behavior of the formed droplets, such as their stability and morphology, and its precise measurement is very effective in the quality control of the mentioned applications. Be. In this research, droplet formation in microfluidic systems due to uniform droplet...
Microfluidic Tensiometry and Investigation of Nanoparticles Adsorption at Liquid/Liquid Interfaces
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Ali Asghar (Supervisor)
Abstract
The present paper is an attempt to critically measure interfacial tension with microchannels and achieve the quantity of adsorption in the liquid – liquid interfaces and comparing the adsorption of surfactants and nanoparticles surface modificated as well. At this point we need to make emulsion and it is necessary for droplets to be monodispersed due to analyze these droplets in this paper. According to this condition for our droplets microsystems are the best options. As we know surfactants were already known as a stabilizing emulsion agent and in this paper nanoparticles are suggested as suitable alternatives for surfactants which can be absorbed as if they are in the water / oil...