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    Forming limit diagrams of ground St14 steel sheets with different thicknesses

    , Article SAE International Journal of Materials and Manufacturing ; Volume 5, Issue 1 , 2012 , Pages 60-64 ; 19463979 (ISSN) Hashemi, R ; Ghazanfari, A ; Abrinia, K ; Assempour, A ; Sharif University of Technology
    The influence of sheet thickness on sheet metal forming limits is a controversial issue; while some investigations indicate the considerable influence of thickness on forming limit diagrams (FLDs), others suggest that it is of negligible importance. In the present work, it has been demonstrated that if the thickness-reduction process is chosen so as not to alter the micro structure of the material, the forming limits do not change with variations of thickness. A material which has extensive usage in sheet metal forming processes of automotive industry (St14) has been provided. The initial thickness of the sheet is 1.5mm and using grinding process (which does not alter the microstructure) the... 

    Evaluation of test collection construction methods: A case study

    , Article 2008 International Conference on Information and Knowledge Engineering, IKE 2008, Las Vegas, NV, 14 July 2008 through 17 July 2008 ; January , 2008 , Pages 16-22 ; 1601320752 (ISBN); 9781601320759 (ISBN) Sheykh Esmaili, K ; Hosseini, M ; Rostami, A ; Abolhassani, H ; Sharif University of Technology
    Currently there is no standard test collection for evaluation of Farsi information retrieval systems. In this paper we introduce Mahak, the first complete test collection generally available for evaluating Farsi information retrieval systems. In addition, we have used different methods for constructing Mahak qrels and we have compared performance of these methods  

    Removal of non-metallic inclusions from nickel base superalloys by electromagnetic levitation melting in a slag

    , Article Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science ; Volume 49, Issue 1 , February , 2018 , Pages 61-68 ; 10735615 (ISSN) Hajipour Manjili, M ; Halali, M ; Sharif University of Technology
    Springer Boston  2018
    Samples of INCONEL 718 were levitated and melted in a slag by the application of an electromagnetic field. The effects of temperature, time, and slag composition on the inclusion content of the samples were studied thoroughly. Samples were compared with the original alloy to study the effect of the process on inclusions. Size, shape, and chemical composition of remaining non-metallic inclusions were investigated. The samples were prepared by Standard Guide for Preparing and Evaluating Specimens for Automatic Inclusion Assessment of Steel (ASTM E 768-99) method and the results were reported by means of the Standard Test Methods for Determining the Inclusion Content of Steel (ASTM E 45-97).... 

    Standard test systems for modern power system analysis: an overview

    , Article IEEE Industrial Electronics Magazine ; Volume 13, Issue 4 , 2019 , Pages 86-105 ; 19324529 (ISSN) Peyghami, S ; Davari, P ; Fotuhi Firuzabad, M ; Blaabjerg, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    The reliable design, planning, and operation of power systems are of paramount importance for providing reliable services to customers. This article reviews the different aspects of power system reliability, ranging from planning to operation. Standard benchmarks employed for power system studies are reviewed according to nearly 2,500 IEEE journal papers from 1986 to early 2019. Our overview provides the pros and cons of existing test systems, implying the lack of appropriate benchmarks for future power system studies, including renewable resources and modern technologies. Furthermore, this article presents requirements for updating and modifying the benchmarks for modern power systems... 

    Continuous ant colony system and tabu search algorithms hybridized for global minimization of continuous multi-minima functions

    , Article Computational Optimization and Applications ; Volume 45, Issue 3 , 2010 , Pages 639-661 ; 09266003 (ISSN) Karimi, A ; Nobahari, H ; Siarry, P ; Sharif University of Technology
    A new hybrid optimization method, combining Continuous Ant Colony System (CACS) and Tabu Search (TS) is proposed for minimization of continuous multi-minima functions. The new algorithm incorporates the concepts of promising list, tabu list and tabu balls from TS into the framework of CACS. This enables the resultant algorithm to avoid bad regions and to be guided toward the areas more likely to contain the global minimum. New strategies are proposed to dynamically tune the radius of the tabu balls during the execution and also to handle the variable correlations. The promising list is also used to update the pheromone distribution over the search space. The parameters of the new method are... 

    On the comprehensive parametrization of the photovoltaic (pv) cells and modules

    , Article IEEE Journal of Photovoltaics ; Volume 7, Issue 1 , 2017 , Pages 250-258 ; 21563381 (ISSN) Hejri, M ; Mokhtari, H ; Sharif University of Technology
    IEEE Electron Devices Society  2017
    In the classical parametrization of the single-diode model of photovoltaic (PV) cells and modules based on the datasheet values, first, the values of the five unknown parameters of the PV model are extracted via the values of the open-circuit voltage Voc, the short-circuit current Isc, and the voltage and current at the maximum power point Vm, Im at standard test conditions (STC). Next, using some translational formulas, the STC values of the unknown parameters are projected to the new climatic conditions other than STC. A major problem of this approach is to determine the translational formulas of the five unknown parameters of the single-diode model as a function of both temperature and... 

    A new method in two phase flow modeling of a non-uniform grid

    , Article Scientia Iranica ; Volume 16, Issue 5 B , 2009 , Pages 425-439 ; 10263098 (ISSN) Bohluly, A ; Borghei, M ; Saidi, M. H ; Sharif University of Technology
    In this paper, a two dimensional numerical model for two phase flow is presented. For interface tracking, the FGVT-VOF (Fine Grid Volume Tracking-Volume Of Fluid) method is selected. For momentum advection, an improved approach is used. In this scheme, a volume tracking step is coupled with steps of computations for the advection of momentum. A Reynolds stress algebraic equation has been implemented in the algorithm of turbulent modeling. Standard test cases are used for the verification of interface tracking and hydrodynamic modeling in laminar and turbulent conditions. The test results show that this methodology can be used in different applications of two-phase flow modeling. © Sharif... 

    Retarding effect of contaminants on the performance of a two-impinging-jets liquid-liquid extraction contactor

    , Article Chemical Engineering and Technology ; Volume 33, Issue 6 , June , 2010 , Pages 1003-1010 ; 09307516 (ISSN) Saien, J ; Doghahe, S. A. O ; Dehkordi, A. M ; Sharif University of Technology
    In industrial liquid-liquid extraction processes, the feed is not clean liquid but there are various kinds of contaminants in the feed entering the extractors. In this regard, a two-impinging-jets contacting device (TIJCD) was tested through the standard test system recommended by the European Federation of Chemical Engineering (EFCE), namely toluene-acetone-water, in the presence and absence of various types of surface-active agents (SAAs). The influences of anionic, cationic, and nonionic SAAs such as sodium dodecyl sulfate (SDS), dodecyl trimethyl ammonium chloride (DTMAC), and octylphenol decaethylene glycol ether (Triton X-100), respectively, on the extraction efficiency and overall... 

    Reliability and validity of the Foot and Ankle Outcome Score: A validation study from Iran

    , Article Clinical Rheumatology ; Volume 29, Issue 5 , 2010 , Pages 479-486 ; 07703198 (ISSN) Negahban, H ; Mazaheri, M ; Salavati, M ; Sohani, S. M ; Askari, M ; Fanian, H ; Parnianpour, M ; Sharif University of Technology
    The aims of this study were to culturally adapt and validate the Persian version of Foot and Ankle Outcome Score (FAOS) and present data on its psychometric properties for patients with different foot and ankle problems. The Persian version of FAOS was developed after a standard forward-backward translation and cultural adaptation process. The sample included 93 patients with foot and ankle disorders who were asked to complete two questionnaires: FAOS and Short-Form 36 Health Survey (SF-36). To determine test-retest reliability, 60 randomly chosen patients completed the FAOS again 2 to 6 days after the first administration. Test-retest reliability and internal consistency were assessed using... 

    Optimal PMU placement for power system observability considering secondary voltage control

    , Article IEEE Canadian Conference on Electrical and Computer Engineering, CCECE 2008, Niagara Falls, ON, 4 May 2008 through 7 May 2008 ; 2008 , Pages 365-368 ; 08407789 (ISSN) ; 9781424416431 (ISBN) Mohammadi Ivatloo, B ; Hosseini, S. H ; Sharif University of Technology
    This paper presents an optimal phasor measurement units (PMUs) placement algorithm for the purpose of power system observability and also increasing the performance of secondary voltage control scheme. The optimal placement problem (OPP) is formulated such that to minimize the number of PMU installations subject to full network observability and monitoring pilot buses of the system to improve secondary voltage control performance. The branch and bound optimization method is adopted to solve the OPP problem which is suitable for problems with integer and boolean variables. Topology-based algorithm is used for observability analysis. Constraint functions considering adjacent zero-injection... 

    Stabilized Meshless Local Petrov-Galerkin (MLPG) method for incompressible viscous fluid flows

    , Article CMES - Computer Modeling in Engineering and Sciences ; Volume 29, Issue 2 , 2008 , Pages 75-94 ; 15261492 (ISSN) Haji Mohammadi, M ; Sharif University of Technology
    In this paper, the truly Meshless Local Petrov-Galerkin (MLPG) method is extended for computation of steady incompressible flows, governed by the Navier-Stokes equations (NSE), in vorticity-stream function formulation. The present method is a truly meshless method based on only a number of randomly located nodes. The formulation is based on two equations including stream function Poisson equation and vorticity advection-dispersion-reaction equation (ADRE). The meshless method is based on a local weighted residual method with the Heaviside step function and quartic spline as the test functions respectively over a local subdomain. Radial basis functions (RBF) interpolation is employed in shape...