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    Design, modeling and optimization of a piezoelectric pressure sensor based on thin-film PZT diaphragm contain of nanocrystalline powders

    , Article 2009 6th International Symposium on Mechatronics and its Applications, ISMA 2009, Sharjah, 23 March 2009 through 26 March 2009 ; 2009 ; 9781424434817 (ISBN) Mohammadi, V ; Sheikhi, M. H ; Torkian, S ; Barzegar, A ; Masumi, E ; Mohammadi, S ; Sharif University of Technology
    2009
    Abstract
    In this paper fabrication of a 0-3 ceramic/ceramic composite lead zirconate titanate, Pb(Zr0.52Ti0.48)O3 thin film has been presented and then a pressure sensor based on multilayer thin-film PZT diaphragm contain of Lead Zirconate Titanate nanocrystalline powders was designed, modeled and optimized. This multilayer diaphragm in general acts as sensor or actuator. ANSYS was used for simulation of diaphragm. Dynamics characteristics of this multilayer diaphragm have been investigated. By this simulation the effective parameters of the multilayer PZT diaphragm for improving the performance of a pressure sensor in different ranges of pressure are optimized. The optimized thickness ratio of PZT... 

    Michael Addition of Anthrone to Nitroolefines in Water and Oxidation of Alkenes Using a Supported Iron Oxide Nanocatalyst

    , M.Sc. Thesis Sharif University of Technology Karimi, Nafiseh (Author) ; Saeedi, Mohammad Reza (Supervisor) ; Ziyaei Halimehjani, Azim (Supervisor) ; Rajabi, Fatemeh (Co-Advisor)
    Abstract
    This projct includes the following sections: In the first section, Michael addition reaction of anthrone to nitroolefins is described in water without using any catalyst to prepare 9-(2-nitro-1-arylethyl)anthracene-10(9H)-ones. This method is green, efficient and gives high yields of products. The solvent effect is also investigated. In the second section, Considerable efforts have been directed in recent years towards the transition metal complex catalyzed oxidation of organic compounds such as olefins, sulfides, benzylics alcohols and phenolics. And due to the various advantages of supported heterogeneous catalysts and in our aim to develop a simple, more efficient and eco-friendly... 

    prediction of Polymeric Membrane Morphology Based on Phase Diagrams for MBR Applications

    , M.Sc. Thesis Sharif University of Technology Mohsenpour, Sajjad (Author) ; Sayf Kordi, Ali Akbar (Supervisor) ; Hemmati, Mahmoud (Supervisor) ; Rekabdar, Fatemeh (Co-Advisor)
    Abstract
    In this research, we have tried to predict the morphology of the membranes that were prepared by phase inversion method. In this research Polyvinylinedifluoride (PVDF) and dimethylacetamide (DMAc) was used as the polymer and solvent. The affect of titanium oxide (TiO2 ) and polyvinylpyrolidene (PVP) which are respectively an inorganic and an organic additive, on the morphology of the membranes was investigated. Ternary and Quadratic phase diagrams were drawn based on the Flory Huggins theory. The interaction between components was determined and the effect of interactions and molar volumes of polymer, solvent, non-solvent and additives on the binodal line was investigated. To predict... 

    Acoustic emission-based methodology to evaluate delamination crack growth under quasi-static and fatigue loading conditions

    , Article Journal of Nondestructive Evaluation ; Volume 37, Issue 1 , March , 2018 ; 01959298 (ISSN) Saeedifar, M ; Ahmadi Najafabadi, M ; Mohammadi, K ; Fotouhi, M ; Hosseini Toudeshky, H ; Mohammadi, R ; Sharif University of Technology
    Springer New York LLC  2018
    Abstract
    The aim of this study was to investigate the applicability of acoustic emission (AE) technique to evaluate delamination crack in glass/epoxy composite laminates under quasi-static and fatigue loading. To this aim, double cantilever beam specimens were subjected to mode I quasi-static and fatigue loading conditions and the generated AE signals were recorded during the tests. By analyzing the mechanical and AE results, an analytical correlation between the AE energy with the released strain energy and the crack growth was established. It was found that there is a 3rd degree polynomial correlation between the crack growth and the cumulative AE energy. Using this correlation the delamination... 

    Data-driven model-free adaptive control of z-source inverters

    , Article Sensors ; Volume 21, Issue 22 , 2021 ; 14248220 (ISSN) Asadi, Y ; Ahmadi, A ; Mohammadi, S ; Moradi Amani , A ; Marzband, M ; Mohammadi Ivatloo, B ; Sharif University of Technology
    MDPI  2021
    Abstract
    The universal paradigm shift towards green energy has accelerated the development of modern algorithms and technologies, among them converters such as Z-Source Inverters (ZSI) are playing an important role. ZSIs are single-stage inverters which are capable of performing both buck and boost operations through an impedance network that enables the shoot-through state. Despite all advantages, these inverters are associated with the non-minimum phase feature imposing heavy restrictions on their closed-loop response. Moreover, uncertainties such as parameter perturbation, unmodeled dynamics, and load disturbances may degrade their performance or even lead to instability, especially when... 

    Effects of Static Shear Stress on Liquefaction Strength of Babolsar Sand Investigated under Cyclic Simple Shear and Static Triaxial Tests

    , M.Sc. Thesis Sharif University of Technology Mohammadi, Morteza (Author) ; Haeri, Mohsen (Supervisor)
    Abstract
    Soil liquefaction is a phenomenon in which soil loses much of its strength or stiffness for a generally short time but nevertheless long enough for liquefaction to be the cause of many losses. Thus, many researchers have worked on the factors which affect this phenomenon. Effects of initial static shear stress on liquefaction strength of loose and medium dense Babolsar sand specimens were investigated in this study. Babolsar sand is fine to medium uniform sand classified as SP in USCS. Tests were performed with cyclic simple shear and static triaxial devices. All tests were performed under consolidated undrained conditions. Cyclic simple shear tests were performed under constant vertical... 

    Providing Marketing Solutions Focused on the "Product" for the Entrance of Miniature Car to Irans Market Via Saipa Corporation

    , M.Sc. Thesis Sharif University of Technology Mohammadi, Elham (Author) ; Beirjandy, Heshmat (Supervisor)
    Abstract
    Miniator car is the first Iranian car that its platform is utterly produced in Iran and would be introduced to the market soon. One of the most important matters for this car’s entrance to the market is considering and responding to the customer needs and requirements. In this thesis the customer needs are identified using the conjoint analysis and Kano method. Using the Kano method the installable elements in introduction phase on Miniator car are classified based on the customers’ point of view. Via conjoint analysis the optional elements of type two of Miniator are identified and then the desirability of each type of Miniator is specified. At last appropriate marketing solutions are... 

    Formal Verification of Privacy Property Using Applied Pi Calculus and Epistemic Logic

    , M.Sc. Thesis Sharif University of Technology Mohammadi, Jamal (Author) ; Ramezanian, Rasoul (Supervisor)
    Abstract
    Applied pi calculus is a variant of the pi calculus with extensions for modeling cryptographic protocols. In such a calculus, the security guarantees are usually stated as equivalences. While process calculi provide a natural means to describe the protocols themselves, epistemic logics are often better suited for expressing certain security properties such as secrecy and anonymity. These methods studied in this work to investigation the verification of privacy properties in security protocols. And finally, a new approach is introduced to bridge the gap between these two approaches: using the set of traces generated by a process as models. In this method an epistemic logic has constructs for... 

    Mass Concrete and a Method for Preventing their Strength Decline

    , M.Sc. Thesis Sharif University of Technology Mohammadi, Abolfazl (Author) ; Khonsari, Vaheed (Supervisor)
    Abstract
    Due to the wide application of Mass Concrete in the body and the foundation of dams, foundations of tall buildings, industrial machinery, and power plants, foundation and piers of bridges, etc.,it is necessary to devise methods in order to prevent the adverse effects of the high volume of such concretes. Since the major negative outcome of high volume is the decrease of the strength of concrete, which in turn is the direct consequence of the cracks resulted from high increase in the temperature within the volume of the concrete as a result of Hydration process and the produced heat which remains inside the bulk of concrete, any solution should involve some form of transferring the heat to... 

    Arithmetic Theory of Quadratic forms with Several Variables

    , M.Sc. Thesis Sharif University of Technology Mohammadi, Rasoul (Author) ; Jafari, Amir (Supervisor)
    Abstract
    In this thesis we review several arithmetical questions about the diophantine equation φ[x]=q where φ is a nondegenerate symmetric bilinear form on a finite dimensional vector space, φ[x] is the corresponding quadratic form and q is a nonzero element of the ground field. We obtain class number and mass formulae for the orthogonal group associated to φ in a number field utilizing the concept of quadratic forms, lattices and adelic language  

    FPGA-based Fault Injection for Evaluating the Fault Tolerance of Embedded Processors

    , M.Sc. Thesis Sharif University of Technology Mohammadi, Abbas (Author) ; Ejlali, Alireza (Supervisor)
    Abstract
    One the most important issues in most of embedded systems is reliability and fault tolerance.Ensure of correct operation and evaluate reliability and fault tolerance of embedded proces-sors as a critical part of embedded systems, would be necessary. Fault injection is one themostly used methods for evaluating those features. Using FPGA devices is a good alterna-tive for time consuming simulation-based fault injection method because of their speed. But,there are some critical issues in FPGA-based fault injection methods which are controllabil-ity and observability. In addition to need for efficient and applicable observation and controlmechanism to handle fault injection experiments, a... 

    Numerical Investigation of Motion of Nanodroplets on Wetting Gradient Surfaces

    , M.Sc. Thesis Sharif University of Technology Mohammadi, Ahmad (Author) ; 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... 

    Optimizing the Total Cost of Inventory Control System in Integrated Multi-Echelon Supply Chain With Time-sensitive Deteriorating Rates

    , M.Sc. Thesis Sharif University of Technology Mohammadi, Vahid (Author) ; hajji, Rasool (Supervisor)
    Abstract
    In this paper, we consider a three-echelon supply chain consisting of a producer, a distributor and a retailer. Generally each echelon tends to minimize his own inventory costs. On the other hand, competitive environment of business market, force companies to develop strategic alliances. In order to boost their partnership, separated echelons must integrate their policies, so that the total cost of the system be minimized. The model, extends the research of Wang et al.(2011) by changing the No shortage assumption into backlog shortage model.
    This study assumes different deterioration rates among different echelons, and deterioration rates are time-sensitive, which is very helpful in... 

    Analysis of Reliability of High Power Amplifier

    , M.Sc. Thesis Sharif University of Technology Mohammadi, Elham (Author) ; 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... 

    Using Wireless Sensor Network for Energy Management of Future Homes

    , M.Sc. Thesis Sharif University of Technology Mohammadi, Sattar (Author) ; Sanaei, Esmaeil (Supervisor)
    Abstract
    We present a home energy management system that is able to manage home energy demand and resources to achieve minimum household payment in electricity dynamic pricing.Communication is used to collect needed data from the home energy system members and users in order toimprove demand and resources management. Some of the needed data comes from appliances and solar panels by wireless sensor network and some other is received from home users by a user interface.
    Two algorithms are proposed that the first algorithm goal is to minimizing household payment and the second algorithm goals are flexible implementiation and decreasing household payment. To decrease household payment, these... 

    An Electromagnetism-Like Algorithm to Solve Three-Dimensional Highway Alignment Problem

    , M.Sc. Thesis Sharif University of Technology Mohammadi, Ali (Author) ; Poorzahedy, Hossein (Supervisor)
    Abstract
    Road construction and maintenance constitute a significant part of country-wide infrastructure development budget each year. This indicates the importance of planning and design of individual road alignment in reducing the development cost. This study presents a meta-heuristic algorithm based on the concept of electromagnetism, which explores and finds a good route between two given points within a three-dimensional (3-D) context. It defines the region in a continuous 3-D surface, identifies initial routes, which are directed and shaped toward better positions by the help of local and global search. The final good solution is fine-tuned to produce a better alignment. The behaviour of the... 

    Optimal ground state energy of two-phase conductors

    , Article Electronic Journal of Differential Equations ; Vol. 2014 , 2014 ; ISSN: 10726691 Mohammadi, A ; Yousefnezhad, M ; Sharif University of Technology
    2014
    Abstract
    We consider the problem of distributing two conducting materials in a ball with xed proportion in order to minimize the rst eigenvalue of a Dirichlet operator. It was conjectured that the optimal distribution consists of putting the material with the highest conductivity in a ball around the center. In this paper, we show that the conjecture is false for all dimensions greater than or equal to two  

    Prioritizing Patients in the Aftermath of Mass Casualty Events Considering Different Resources

    , M.Sc. Thesis Sharif University of Technology Mohammadi, Reyhaneh (Author) ; Shavandi, Hassan (Supervisor)
    Abstract
    In the aftermath of mass-casualty events, main resources may be overwhelmed by the sudden jump in demand. To ration these resources with considering the patients priority for help, mean triage. For prioritizing the patient for help, the limitation of resources should be considered. These resources can be different. This thesis at the first step investigates how the priority assignment can be done in a clearing system and what the potential benefits would be when there are same resources in the system. At the next step, the difference between resources is considered. So in this thesis, the problem of priority assignment of patients in an emergency system is modeled and analyzed at first with... 

    Design and Prototyping of Magnetic Gearboxes Test Stand

    , M.Sc. Thesis Sharif University of Technology Mohammadi, Kaivan (Author) ; Durali, Mohammad (Supervisor)
    Abstract
    There are two ways for quality control testing of power transmission systems in various industries. A method of testing the specific positions of power transmission, and final testing (Automotive road tests), respectively. In various stages of design, manufacturing and quality control components, power transmission systems, require detailed information on the performance of parts. It's a special place for each transmission experiment designed and manufactured. Gearbox as an important component of the transmission of this issue is no exception. Magnetic gearbox has a new generation of power transmission systems in the last decade of the optimization is presented. In recent years, several... 

    Numerical Modeling of the Bahavior of Unsaturated Soils with the BBM in the FLAC Software

    , M.Sc. Thesis Sharif University of Technology Mohammadi, Hojjat (Author) ; 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...