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    Analytical modeling of magnetic flux in superconducting synchronous machine

    , Article IEEE Transactions on Applied Superconductivity ; Volume 23, Issue 1 , 2013 ; 10518223 (ISSN) Yazdanian, M ; Elhaminia, P ; Zolghadri, M. R ; Fardmanesh, M ; Sharif University of Technology
    2013
    Abstract
    A general model for superconducting synchronous machines in which the rotor can be considered as a magnetic or a nonmagnetic material is proposed and analytically investigated. Analytical equations for magnetic flux in different regions of the machine have been developed. Furthermore, nonlinear magnetization of the iron core is studied. In order to solve the equations in the case of the iron saturation, a reiterative algorithm is proposed. Finite-element simulation has also been performed to verify the equations and the proposed algorithm. The obtained analytical results show good agreement with finite-element method results  

    Permeability impairment study due to asphaltene deposition: experimental and modeling approach

    , Article Transport in Porous Media ; Volume 91, Issue 3 , February , 2012 , Pages 999-1012 ; 01693913 (ISSN) Bolouri, S. H ; Ghoodjani, E ; Sharif University of Technology
    2012
    Abstract
    This fact is well known that during any scenario of production, asphaltene deposition in porous media has a substantial effect on oil flow. But a clear understanding of asphaltene deposition mechanisms can help to minimize asphaltenic problem in oil-bearing formations. In this study, the experimental results of three dynamic CO 2 miscible injection tests were investigated. Regarding the effects of adsorption, mechanical entrapment, and sweeping mechanisms on permeability behavior, a mathematical mass and permeability variation model were developed. According to the experimental results asphaltene deposition causes a 70% loss of sand stone initial permeability while the loss is significantly... 

    An analytical approach for optimal design of rotor iron for superconducting synchronous machine

    , Article IECON Proceedings (Industrial Electronics Conference), 7 November 2011 through 10 November 2011, Melbourne, VIC ; 2011 , Pages 1741-1745 ; 9781612849720 (ISBN) Elhaminia, P ; Yazdanian, M ; Zolghadri, M. R ; Fardmanesh, M ; Sharif University of Technology
    2011
    Abstract
    Although iron-cored superconducting machine has been recently proposed in many papers for its advantages over conventional air-cored structure such as less cost and less perpendicular magnetic component on HTS tapes it has not been studied analytically yet. This paper analytically investigates a general model for iron-cored superconducting synchronous machine. In this paper, analytical equations for magnetic flux in different regions of machine have been proposed along with an algorithm to solve the equations. The analytical equations will be then used to optimize the thickness of rotor iron in order to maximize the machine power density. Analytical and finite element simulation results will... 

    Swarm aggregation using emotional learning based intelligent controller

    , Article 2009 6th International Symposium on Mechatronics and its Applications, ISMA 2009, Sharjah, 23 March 2009 through 26 March 2009 ; 2009 ; 9781424434817 (ISBN) Etemadi, S ; Vatankhah, R ; Alasty, A ; Vossoughi, G ; Sharif University of Technology
    2009
    Abstract
    In this paper, we consider a control strategy of multi-robot systems, or simply, swarms, based on emotional control technique. First, we briefly discuss a "kinematic" swarm model in n-dimensional space introduced in an earlier paper. In that model, motion of every swarm member is governed by predefined inter-individual interactions. Limitations of every member's field of view are also considered in that model. After that, we consider a general model for vehicle dynamics of each swarm member, and use emotional control theory to force their motion to obey the dynamics of the kinematic model. Based on the kinematic model, stability (cohesion) analysis is performed and coordination controller is... 

    An analytical framework for the solution of autofrettaged tubes under constant axial strain condition

    , Article ASME 2008 Pressure Vessels and Piping Conference, PVP2008, Chicago, IL, 27 July 2008 through 31 July 2008 ; Volume 5 , July , 2008 , Pages 71-80 ; 0277027X (ISSN); 9780791848289 (ISBN) Hosseinian, E ; Farrahi, G. H ; Movahhedy, M. R ; Pressure Vessels and Piping ; Sharif University of Technology
    2008
    Abstract
    Autofrettage is a technique for introducing beneficial residual stresses into cylinders. Both analytical and numerical methods are used for analysis of the autofrettage process. Analytical methods have been presented only for special cases of autofrettage. In this work, an analytical framework for the solution of autofrettaged tubes with constant axial strain conditions is developed. Material behavior is assumed to be incompressible and two different quadratic polynomials are used for strain hardening in loading and unloading. Clearly, elastic-perfectly plastic and linear hardening materials are special cases of this general model. This material model is convenient for description of the... 

    On the hardware-software partitioning: The Classic General Model (CGM)

    , Article 2006 Canadian Conference on Electrical and Computer Engineering, CCECE'06, Ottawa, ON, 7 May 2006 through 10 May 2006 ; 2006 , Pages 1922-1925 ; 08407789 (ISSN); 1424400384 (ISBN); 9781424400386 (ISBN) JavanHemmat, H ; Goudarzi, M ; Hessabi, S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2006
    Abstract
    In this paper we introduce a mathematical modeling tool (called Classic General Model: CGM) for the general problem of hardware-software codesign so that different partitioning algorithms can be easily and quickly developed and compared in this same framework. CGM introduces a simple but efficient model which supports single/multiprocessor, primal and dual approaches, fine or coarse granularity. CGM determines solutions by stating Mapping, Implementation and Permutation arrays. For judging among solutions of a certain algorithm, an Objective Function is defined. After modeling the problem by CGM we have a classic problem: finding the best values for elements of three arrays to optimize the... 

    Identification of aircraft dynamics, using neural network simultaneous optimization algorithm

    , Article 19th Annual European Simulation and Modelling Conference, ESM 2005, Porto, 24 October 2005 through 26 October 2005 ; 2005 , Pages 172-176 Saghafi, F ; Heravi, B. M ; Sharif University of Technology
    EUROSIS  2005
    Abstract
    In this paper, the ability of the neural network based system identification for aircraft modeling and simulation is investigated. The focus of this paper is to obtain methods for improving generalization of the neural network based aircraft models which are going to be used in aircraft simulators. The genetic algorithm is used to simultaneously train and optimize a modified Elman network architecture. It is shown that this method improves generalization in system identification of aircraft dynamics  

    A general model for multicomponent transport in nonporous membranes based on Maxwell-Stefan formulation

    , Article Chemical Engineering Communications ; Volume 191, Issue 4 , 2004 , Pages 460-499 ; 00986445 (ISSN) Ghoreyshi, A. A ; Farhadpour, F. A ; Soltanieh, M ; Sharif University of Technology
    Taylor and Francis Ltd  2004
    Abstract
    A "general" model of membrane transport was formulated using the mechanistic Maxwell-Stefan approach and generalized driving forces, which included the contribution from the various internal and external driving forces. Transient models of dialysis and pervaporation were developed that used exactly the same general model to describe the transport through the membrane. In this model, the bulk solution/polymer equilibria were described by a modified Flory-Huggins model, and the concentration dependence of ternary Maxwell-Stefan diffusivities was described by a natural extension of the binary Vignes relationship to a multicomponent system. A notable advantage of the general model lies in the... 

    Swarm aggregation using emotional learning based intelligent controller

    , Article 2009 6th International Symposium on Mechatronics and its Applications ; 2009 , Article number 5164827 ; ISBN: 9781424434817 Etemadi, S ; Vatankhah, R ; Alasty, A ; Vossoughi, G ; Sharif University of Technology
    Abstract
    In this paper, we consider a control strategy of multi-robot systems, or simply, swarms, based on emotional control technique. First, we briefly discuss a "kinematic" swarm model in n-dimensional space introduced in an earlier paper. In that model, motion of every swarm member is governed by predefined inter-individual interactions. Limitations of every member's field of view are also considered in that model. After that, we consider a general model for vehicle dynamics of each swarm member, and use emotional control theory to force their motion to obey the dynamics of the kinematic model. Based on the kinematic model, stability (cohesion) analysis is performed and coordination controller.is... 

    An analytical framework for the solution of autofrettaged tubes under constant axial strain condition

    , Article Journal of Pressure Vessel Technology, Transactions of the ASME ; Volume 131, Issue 6 , 2009 ; 00949930 (ISSN) Hosseinian, E ; Farrahi, G. H ; Movahhedy, M. R ; Sharif University of Technology
    Abstract
    Autofrettage is a technique for introducing beneficial residual stresses into cylinders. Both analytical and numerical methods are used for the analysis of the autofrettage process. Analytical methods have been presented only for special cases of autofrettage. In this work, an analytical framework for the solution of autofrettaged tubes with constant axial strain conditions is developed. Material behavior is assumed to be incompressible, and two different quadratic polynomials are used for strain hardening in loading and unloading. Clearly, elastic perfectly plastic and linear hardening materials are the special cases of this general model. This quadratic material model is convenient for the...