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    Friction Power and Appropriate Lubrication System in Rotary (Wankel) Engines

    , M.Sc. Thesis Sharif University of Technology Gerami Kaviri Nejad, Alireza (Author) ; Mozafari, Ali Asghar (Supervisor)
    In this study an internal combustion rotary (Wankel) engine and its specifications is analyzed and the proper lubrication system is described. The acceleration acting on apex seals, and engine speed fluctuations together with the leading and trailing cells gas pressure forces are analyzed in the present work using the second Newton law. The research shows that cell gas pressure effects are important and inclusion of these effects will provide results which are more compatible with the reality and lead to a much more accurate analysis of the system. Theoretical calculations reveal that gas cell pressure forces represent about 78% of the overall calculated force and ignoring these pressure... 

    , M.Sc. Thesis Sharif University of Technology Zadkhast, Sajad (Author) ; Mokhtari, Hosain (Supervisor)
    By taking a new sight into the system dynamic equations, the controllers are designed based on the simplification and converting higher order dynamics to the first order systems. This issue not only simplifies controller design but also stabilize system in all operational points. Moreover, proposed controllers are applied to the parallel Active Power Filters (APFs) because of the new trends in modularizing of APFs. On the other hand, the IEEE-1459 standard has proposed new definitions for the power in unbalanced and non-sinusoidal conditions and it stimulated researchers to use this standard for controlling APF directly. However, the proposed definitions are based on RMS values and... 

    Robust Optimization of Portfolio with Stock Options

    , M.Sc. Thesis Sharif University of Technology Hassanzadeh Mofrad, Maryam (Author) ; Modarres Yazdi, Mohammad (Supervisor)
    In this thesis, we apply robust optimization to analyze the uncertainty of model parameters of a portfolio optimization which contains stock options. We also develop two robust counterpart models for single period and multiperiod problems. By assuming that the probability distribution of parameters is not known, their uncertainty is considered to lie within known linear intervals. Due to the existence of nonlinear relations (piecewise linear) between uncertain data (stock and option price), we present an over-conservative robust model to make the solution feasible for all parameters. However in the second model by adopting a different approach we develop a robust counterpart model with... 

    Experimental Study of the Performance of a Multi-Tube Pulse Detonation Engine

    , M.Sc. Thesis Sharif University of Technology Eidi Attar Zade, Masoud (Author) ; Farshchi, Mohammad (Supervisor) ; Ghorbanian, Kaveh (Supervisor)
    Performance of a multi tube pulse detonation engine has been investigated experimentally. A pulse detonation engine uses detonation phenomena and simply consists of a large narrow tube which has closed head, and has feeding system and ignition system. In this tube, detonation is produced periodically to generate thrust. In multi-tube mode, several tubes are arranged in parallel which detonate sequentially. Our PDE consists of 2 tubes with 70 cm length and 25 mm inner diameter which have several places performed for high speed pressure sensors installation. The premixed hydrogen-oxygen mixture are controlled by solenoid valve and injected on head-end and ignited by conventional spark plug.... 

    An Engineering Approach to Software Modeling Language Development

    , Ph.D. Dissertation Sharif University of Technology Kamandi, Ali (Author) ; Habibi, Jafar (Supervisor)
    Nowadays, the essentiality of appropriate modeling languages has become evident, and with the introduction of new concepts such as domain-specific languages, the need for systematic research on designing and engineering new modeling languages has increased significantly. Several modeling languages have been developed and employed over the years, but the area of modeling languages still suffers from the lack of a proper framework: There is a strong need for an engineering framework that specifies the detailed steps of language development, the input and output artifacts of each step, the techniques applicable to each step, and quantifiable methods for quality measurement. From a unified point... 

    Management of System Requirements in Systems Engineering Process with Axiomatic Design Principles

    , M.Sc. Thesis Sharif University of Technology Mollajan, Ali (Author) ; Malaek, Mohammad Bagher (Supervisor)
    Functional Requirements (FR) are traditionally known to be "input" as far as an engineering process is concerned. However, for a Systems Engineer (SE), this is not the case. A well-known task of a SE is, in fact, to develop FRs from what is considered as the customer needs. The traditional approach to develop suitable FRs involves an algorithmic procedure; which mostly relies on the skills, knowledge, attitude, and experiences of the SE or experts members of design team. It is therefore an ad-hoc method which results in quite a few numbers of trial-errors and its effectiveness only reveals itself as time goes on. The current work aims to address such a shortcoming in Systems Engineering... 

    Manufacturing and Characterization of Bone Scaffold Based on TCP

    , M.Sc. Thesis Sharif University of Technology Gorgin Karaji, Zahra (Author) ; Bagheri, Reza (Supervisor)
    Bone scaffolds are combinations of several materials, for achieving suitable properties and usage for replacing with defected bone. In this study, TCP/Agarose scaffolds are fabricated by two different approaches. The first one is using polymer sponge and gel casting technique and the other one is using foaming agent in order to obtain scaffolds with same porosity. The results show that in spite of same structure and porosity, scaffolds have different mechanical properties due to their different morphologies. Compressive strength of the scaffolds which were fabricated using polymer sponge method is 2.25MPa and elastic modulus is 56.8MPa. After coating with Agarose, compressive strength... 

    Expansion of Power Definition in IEEE-1459 in Order to Apply to Shunt Active Power Filters

    , M.Sc. Thesis Sharif University of Technology Ahmadi, Meysam (Author) ; Mokhtari, Hossein (Supervisor)
    Increase of nonlinear loads has led rise of harmonic currents, voltage distortion and imbalance in power system. Those polluted nonsinusuidal environments have made electrical engineer and researchers to define new and more compelet definition of electrical power quantities such as power factor, apparent power, THD and … . The new definitions have resulted in new methods of power quality enhancement technique. IEEE-1459 Std. proposes definitions for electric power in sinusoidal, nonsinusoidal, balanced and unbalanced conditions which can be used for compensation of nonsinusoidal and unbalanced systems. This reaserch introduces a new method to obtain shunt active filter reference signal. This... 

    Study of Adaptable Organizational Structures for Entering International Protocols Case Study: Carbon Trade

    , M.Sc. Thesis Sharif University of Technology Kamali Miab, Ali (Author) ; Malaek, Mohammad Bagher (Supervisor) ; Kaymaram, Farid (Supervisor)
    In this research a systemic framework for recognizing and using international opportunities has been generated based on the Viable System Model (VSM). This framework consists of designing required functions, recognizing capabilities and assigning requirements in the different levels of the system. Based on this framework a systemic analysis for diagnosing Iran’s problems and barriers in implementing Clean Development Mechanism (CDM) which is a part of international carbon trade has been done. This research results show that the generated systemic framework has a good diagnosing power for identifying systemic problems in different systems  

    Analysis of Value Engineering in Construction Projects with Executive Solutions - Including a Case Study

    , M.Sc. Thesis Sharif University of Technology Fatemi, Mohammad Ali (Author) ; Mostafavi, Mostafa (Supervisor)
    This research represents findings about obstacles in using value engineering in construction projects of khorasan razavi province via collection of information and views of experts of value engineering.The research shows that the value engineering in the majority of the projects is not practiced and majority of the projects are not benefited from this technique. Many experts believe that lack of required culture and motivation to save up and lack of organisational position for this technique are the main factors for non-progressive use of assessment engineering.The absence of proper understanding of the objectives and place of the value engineering is also an effective factor of on its... 

    A Framework for Requirements Engineering in Situational Method Engineering

    , M.Sc. Thesis Sharif University of Technology Jafarinezhad, Omid (Author) ; Ramsin, Raman (Supervisor)
    Practitioners and researchers working on Software Development Methodologies (SDM) have always sought for ways to raise the degree of flexibility in SDMs, so that methodologies can be adjusted to specific project situations. Methodology Engineering (ME) approaches are being pursued to this aim, giving rise to Situational Method Engineering (SME). As the pivotal phase of software development, Requirements Engineering (RE) has proved essential in SME; however, SME has a long way to go as to its support for specialized RE practices. The RE practices employed in software engineering seem to provide a rich resource for strategies and techniques that can address this issue, if properly attuned to... 

    Design and Integration of a Connected Pipe Test Facility for Liquid Fuel Ramjet

    , M.Sc. Thesis Sharif University of Technology Tavassoli, Farid (Author) ; Mazaheri, Karim (Supervisor)
    In the present study, design and manufacturing of a connected pipe liquid fuel ramjet test platform is implemented for performance investigation of a research liquid fuel ramjet burner in the thermodynamic flight conditions. Design and manufacturing of platform systems include: the hot air supply system, the liquid fuel system and the square cross-sectional combustion chamber with the v-gutter shape flame holder. In order to determine the performance range of subsystems, calibration process has been carried out. Calibration process of the hot air supply system includes: determining of the burner inlet velocity and temperature. Also, calibration of the liquid fuel system includes: determining... 

    Development of a Set of Enterprise Architecture Process Patterns

    , M.Sc. Thesis Sharif University of Technology Ahmadi, Mohammad Hossein (Author) ; Ramsin, Raman (Supervisor)
    The discipline of enterprise architecture (EA) is concerned with applying the concept of system architecture to enterprises, esp. to their information technology, so as to create a common perspective, facilitate understanding and improvement of the enterprise, and help better organizational change management. EA methodologies are used for modeling, planning, implementation and management of EA. A plethora of such methodologies have been introduced in recent decades, that widely differ in terms of structure, content and terminology, which has hindered their evaluation, comparison and selection. Furthermore, a consensus has emerged that EA methodologies should be contingent on the specifics of... 

    Development of a Process Line Engineering Approach Based on Product Line Engineering Methods for Engineering Agent Oriented Methodologies

    , M.Sc. Thesis Sharif University of Technology Golpayegani, Fatemeh (Author) ; Ramsin, Raman (Supervisor)
    Product Line Engineering (PLE) is a well-established discipline in software engineering, and has gained widespread adoption in industry. Software product lines are considered an efficient means for mass production of software systems, and many companies have based their software development processes on PLE principles and practices.
    Situational Method Engineering (SME) has so far been mainly concerned with metamodels and method chunk repositories; through using these means, methodologies are constructed or extended to address the specific requirements of a software development project. A recent development in SME is the introduction of “Process” Line Engineering, which promises new... 

    Modeling of the Mechanical Behavior of Rapid Prototyped Scaffolds Based on Their Pore Architecture and Introducing a Prototyping Method to Produce Ceramic Scaffolds

    , Ph.D. Dissertation Sharif University of Technology Amirkhani, Soodeh (Author) ; Bagheri, Reza (Supervisor) ; Baghaban Eslaminejad, Mohamad Reza (Supervisor)
    Mechanical behavior of tissue engineering scaffolds plays a key role in their biological performance; however the effect of microstructural features on mechanical behavior of such scaffolds is still under investigation. The objective of this study was to investigate the influence of pore architecture and relative density on mechanical behavior of rapid prototyped scaffolds. In this regard, scaffolds with different cubic, hexagonal and trigonal unit cells were designed. These unit cells were repeated in different arrangements in 3D space to produce different nodal connectivities. The internal dimension of pores varied from 500 to 600 μm. Plastic models of scaffolds then fabricated by 3D... 

    Flexibility Analysis in Supply Chain by Using Design Structure Matrix

    , M.Sc. Thesis Sharif University of Technology Yousefi, Zahra (Author) ; Malaek, Mohammad Bagher (Supervisor)
    Supply chains are socio-technical engineering systems which now days perform in more uncertain operational environment than before. These systems have been vulnerable because of increasing the number of natural disasters, competitiveness and changing the demand. So these systems in order to be survived in such high uncertain environment need to enhance some capabilities in their structure. In this research by considering an assumed auto supply chain, we try to develop an approach to cover uncertainties in operational environment of this system. At the next step, we use design structure matrix modeling to model the interactions between system elements before and after scenario occurring.... 

    Feasibility Study of Culturing and Differentiating Mesenchymal Stem Cells to Smooth Muscle Cells in Nanostructured PCL Hybrid Scaffold

    , M.Sc. Thesis Sharif University of Technology Moghadasi, Samaneh (Author) ;
    Tissue engineering is an interdisciplinary field that incorporates principles of engineering with the life sciences. Tissue engineering consists of three principle; cells, scaffolds for cells expansion and growth factors. These factors together can help tissue engineers to provide appropriate microenvironments for directing special cells behavior.
    Fibrous scaffolds have found many applications in tissue engineering due to their nanometer dimensions and high surface to volume ratio. Fibrous scaffolds can impart mechanical strength, structure for cell attachment and act as reservoirs for biomolecule delivery in much a same way as the natural fibrous components of the extracellular... 

    Fabrication and Characterization of Thermoplastic Starch Based Nanocomposite for Bone Scaffold

    , M.Sc. Thesis Sharif University of Technology Mahdieh, Zahra (Author) ; Bagheri, Reza (Supervisor)
    This project aimed to fabricate the bone scaffolds with applying thermoplastic starch-based nano-biocomposites. The starting materials for this scaffold are as follows: thermoplastic starch, ethylene vinyl alcohol as the polymer matrix and nanoforsterite as the ceramic reinforcing phase. Furthermore, vitamin E was used as antioxidant for preserving starch against thermo-mechanical degradations. Likewise, 3D pore structure was developed using azo-dicarbonamide and water in injection moulding process. With blending thermoplastic starch and ethylene vinyl alcohol, some thermoplastic starch’s properties including degradation rate and water absorption were modified. In addition, having... 

    Design and Numerical Optimization of Hot Air Supply System of Connected-pipe Ramjet Engine Test Facility

    , M.Sc. Thesis Sharif University of Technology Nazem Roaya, Mohammad Amin (Author) ; Mazaheri, Karim (Supervisor)
    In the present study an air supply system of a connected-pipe ramjet test facility for liquid fuel ramjet engine in theoretical and numerical base designed and optimized that the purpose is for performance test of a ramjet engine combustor in flight condition. The flight condition gained from previous assessment that is 1.5 kg air in 10 bars and 550 K. Air supply subsystems consist of air tanks, compressors, valves, regulators, preheater, and fuel and oxygen systems that are designed in a preliminary process and then valves, orifices, and fuel and oxygen systems optimized by HYSYS program. In the last step preheater that is a gas turbine combustor investigated and possible changes made by... 

    Dynamic Model Identification of a 4th Generation Turbojet Engine’s FCU Using Parametric Frequency Response Analysis

    , M.Sc. Thesis Sharif University of Technology Yazdani, Amin (Author) ; Banazadeh, Afshin (Supervisor)
    In this thesis, dynamics of a turbojet’s fuel control unit is studied for the nature and the range of its inputs and outputs. Then, inputs and outputs involved in the system identification process are determined. Tools needed for the application of the input and the signal data sampling are recognized, and henceforth, with the appropriate input applied and the frequency-domain system identification process carried out, desired linear transformation functions representing dynamics of the fuel control unit are found. Using these transformation functions, the fuel control unit is simulated to be converted to an electronic control unit