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    Experimental investigation of two phase flow in horizontal wells: Flow regime assessment and pressure drop analysis

    , Article Experimental Thermal and Fluid Science ; Volume 88 , 2017 , Pages 55-64 ; 08941777 (ISSN) Shams, R ; Tavakoli, A ; Shad, S ; Sharif University of Technology
    Elsevier Inc  2017
    Abstract
    Multiphase flow is fundamental to different fields of engineering and science including petroleum engineering. In oil and gas, flow of multiple phases inside wells is a common phenomenon. In such conditions, petroleum engineers deal with different design and operational difficulties due to complexities involved in flow of multiple phases inside a well. Unlike flow of gas and liquid inside a well, the liquid-liquid flow inside a horizontal well has received rather less attention. This study is aimed at experimentally investigating multiphase flow in a horizontal well by using a 12 m length and 30 mm diameter well made of Plexiglas. Despite the importance of defining pattern transition... 

    Holistic change management: importance and methodological challenges

    , Article 2017 IEEE Technology and Engineering Management Society Conference, TEMSCON 2017, 8 June 2017 through 10 June 2017 ; 2017 , Pages 272-276 ; 9781509011148 (ISBN) Shams, A ; Sharif, H ; Kermanshah, A ; Sharif University of Technology
    2017
    Abstract
    various researchers and practitioners have identified a range of problems and deficiencies with existing change-related frameworks, while each framework can include unique valuable elements in its people/process/technology aspects and theoretical foundations. In such a setting, we have adopted a holistic approach through examining an armada of existing frameworks and methodologies. Several decades of combined intercontinental experience of the authors (and much more from their academic/practice network) in the field of change management is culminating in development of a novel overarching framework referred to as Total Change Management (TCM). In the three years course of establishment of... 

    Simulation of rarefied gas flows in MEMS/NEMS using a molecular method

    , Article Proceedings of the ASME Fluids Engineering Division Summer Conference 2009, FEDSM2009, 2 August 2009 through 6 August 2009 ; Volume 1, Issue PART B , 2009 , Pages 1039-1044 ; 9780791843727 (ISBN) Ghezel Sofloo, H ; Ebrahimi, R ; Shams, A ; Sharif University of Technology
    2009
    Abstract
    In this work, the development of a two-dimensional Direct Simulation Monte Carlo (DSMC) Program for pressure boundaries using unstructured cells and its applications to typical micro-scale gas flows are described. For the molecular collision kinetics, variable hard sphere molecular model and no time counter collision sampling scheme have been used. Applications to micro-scale gas flows include micro-nozzel, nano channel and slider air bearing.The aim is to further test the treatment of pressure boundaries. For slider air bearing gas flows of the computer hard drive, the simulated gas pressures, at different rotating speeds, have a very good agreement with previous studies. The applicability... 

    Desulfurization of liquid-phase Butane by zeolite molecular sieve 13X in a fixed bed: Modeling, simulation, and comparison with commercial-scale plant data

    , Article Energy and Fuels ; Volume 22, Issue 1 , 2008 , Pages 570-575 ; 08870624 (ISSN) Shams, A ; Molaei Dehkordi, A ; Goodarznia, I ; Sharif University of Technology
    2008
    Abstract
    This paper deals with the modeling and simulation of binary liquid-phase adsorption of methyl mercaptan and hydrogen sulfide from a liquid butane stream by zeolite molecular sieve 13X in a fixed bed. The model equations account for the effect of axial dispersion and the inter- and intraparticle, mass-transfer resistances at isothermal operating conditions. Orthogonal collocation and Gill's fourth-order Runge-Kutta methods were used to solve the dimensionless general forms of the 4N-eoupled ordinary differential equations for simultaneous adsorption of the solutes by the adsorbent in a fixed bed. The model predictions were compared to the commercial-scale plant data of an Iranian... 

    Spectral method for solving differential equation of gas flow through a micro-nano porous media

    , Article Journal of Computational and Theoretical Nanoscience ; Volume 7, Issue 3 , 2010 , Pages 542-546 ; 15461955 (ISSN) Taghavi, A ; Parand, K ; Shams, A ; Sofloo, H. G ; Sharif University of Technology
    2010
    Abstract
    In this paper we propose, Spectral method to solve unsteady gas equation which is a nonlinear ordinary differential equation on semi-infinite interval. These approaches are based on Modified generalized Laguerre functions. These methods reduces the solution of this problem to the solution of systems of algebraic equations. We also compare this works with some other numerical results  

    Effects of contact angle hysteresis on drop manipulation using surface acoustic waves

    , Article Theoretical and Computational Fluid Dynamics ; Volume 34, Issue 1-2 , 2020 , Pages 145-162 Sheikholeslam Noori, M ; Taeibi Rahni, M ; Shams Taleghani, A ; Sharif University of Technology
    Springer  2020
    Abstract
    Surface acoustic waves have gained much attention in flow control given the effects arising from acoustic streaming. In this study, the hydrodynamic interference of a drop under surface acoustic waves is comprehensively investigated and the contact angle hysteresis effects are considered, too. This paper reveals the effects of some control parameters such as wave amplitude and wave frequency on the dynamical behaviors of drop. For these purposes, a multiple-relaxation-time color-gradient model lattice Boltzmann method is developed. In these case studies, wave frequency and amplitude were in the ranges of 20–60 MHz and 0.5–2 nm, respectively. In addition, the density ratio of 1000, the... 

    Seismic Design of Substation Structures with Consideration of IEEE-693

    , M.Sc. Thesis Sharif University of Technology Shams, Mohammad (Author) ; Mofid, Massoud (Supervisor)
    Abstract
    The Reliability of substation structures with consideration of earthquake uncertainties is one of the most important subjects in structural analysis in recent years. In this project we first introduce IEEE-693-2005, which is the most effective and comprehensive seismic design code for electronic substations. Also in second chapter the rudimentary aspects of Reliability Theory and methods for evaluating the reliability of substation structures is introduced. Then with modeling the most common and most important electronic substation devices in Iran, with consideration of all seismic parameters and their uncertainties, the reliability of these structures evaluated. In this project for... 

    Scheduling on Parallel Machines with Preemption and Transportation Delays using a Particle Swarm Optimization (PSO)-Based Algorithm

    , M.Sc. Thesis Sharif University of Technology Shams, Hesam (Author) ; Shadrokh, Shahram (Supervisor)
    Abstract
    This research deals with the problem of scheduling independent preemptive jobs on identical parallel machines, to minimize the total completion time (makespan). The transportation of an interrupted job from a machine to another machine requires considering a constant transportation delay i.e., Pm|prmp(delay)| Cmax. This delay is called transportation delay. We propose a Mixed Integer Linear Programming formulation for the research problem in case of two machines i.e., P2|prmp(delay)| Cmax. Since the research problem is shown to be NP-hard, a particle swarm optimization (PSO) algorithm is applied to solve the problem approximately. Based on the frequency of using local search procedure, three... 

    Speaker Adaptation in Eigen Voice Space for Statistical Parametric Speech Syntheis

    , M.Sc. Thesis Sharif University of Technology Shams, Boshra (Author) ; Sameti, Hossein (Supervisor)
    Abstract
    Recently various speaker adaptation methods in HMM-based speech synthesis are proposed. The importance of adaptation techniques is that we can design a system in which speech is generated with high quality and target speaker characteristics through limited adaptation data sets.
    In this research, we focus on adaptation based on clustering and develop a new and novel method using eigenvoices in order to adapt a new speaker. We employ this approach for the first time in HSMM-based speech synthesis systems and its goal is to reduce the parameters and adaptation data of the system. In our proposed method, first some speaker dependent models are trained. For each model we combine the... 

    Parallel machine scheduling problem with preemptive jobs and transportation delay

    , Article Computers and Operations Research ; Vol. 50, issue , Oct , 2014 , p. 14-23 Shams, H ; Salmasi, N ; Sharif University of Technology
    2014
    Abstract
    In this research the parallel machine scheduling problem with preemption by considering a constant transportation delay for migrated jobs and minimization of makespan as the criterion i.e., Pm|pmtn(delay)|Cmax is investigated. It is assumed that when a preempted job resumes on another machine, it is required a delay between the processing time of the job on these two machines. This delay is called transportation delay. We criticize an existing mathematical model for the research problem in the literature [Boudhar M, Haned A. Preemptive scheduling in the presence of transportation times. Computers & Operations Research 2009; 36(8):2387-93]. Then, we prove that there exists an optimal schedule... 

    A Simulation for Better Understanding of Integrin Clustering and Activation

    , M.Sc. Thesis Sharif University of Technology Shams, Shahab (Author) ; Motahhari, Abolfazl (Supervisor)
    Abstract
    Today, computer simulations are employed prevalently by researchers to understand biological processes. The tendency to use computational methods has been increased recently due to the high costs and errors of experimental methods. Integrins are membrane proteins that mechanically attach cells to the extra cellular matrix (ECM) and derive some behaviors such as cell migration. Moreover, integrins have biochemical functions. They transduce environment signals and trigger chemical pathways. As a result, integrins regulate cell shape, motility, etc. The investigation of integrin behavior in a real environment is very difficult due to the presence of many other proteins that interfere with the... 

    Experimental study of two-phase oil – Polymer flow in horizontal flow path

    , Article Experimental Thermal and Fluid Science ; Volume 100 , 2019 , Pages 62-75 ; 08941777 (ISSN) Shams, R ; Shad, S ; Sharif University of Technology
    Elsevier Inc  2019
    Abstract
    Two-phase flow inside the oil and gas wells and flow path lines is a usual occurrence in petroleum and petrochemical studies. Due to its complexity, flow transfer parameters such as hold up and pressure drop and their dependency on the flow regime maps are not well understood yet. This study is aimed at analyzing holdup for oil- water system and evaluation of this parameter by means of Image processing under different available flow regime conditions. In addition, different oil-polymer systems have been studied to evaluate the impact of polymer concentration on transport criteria. The experimental setup used for this study is consisted of a 12 m long Plexiglas pipe with an inner diameter of... 

    Experimental study of two-phase oil – Polymer flow in horizontal flow path

    , Article Experimental Thermal and Fluid Science ; Volume 100 , 2019 , Pages 62-75 ; 08941777 (ISSN) Shams, R ; Shad, S ; Sharif University of Technology
    Elsevier Inc  2019
    Abstract
    Two-phase flow inside the oil and gas wells and flow path lines is a usual occurrence in petroleum and petrochemical studies. Due to its complexity, flow transfer parameters such as hold up and pressure drop and their dependency on the flow regime maps are not well understood yet. This study is aimed at analyzing holdup for oil- water system and evaluation of this parameter by means of Image processing under different available flow regime conditions. In addition, different oil-polymer systems have been studied to evaluate the impact of polymer concentration on transport criteria. The experimental setup used for this study is consisted of a 12 m long Plexiglas pipe with an inner diameter of... 

    Review of data science trends and issues in porous media research with a focus on image-based techniques

    , Article Water Resources Research ; Volume 57, Issue 10 , 2021 ; 00431397 (ISSN) Rabbani, A ; Fernando, A. M ; Shams, R ; Singh, A ; Mostaghimi, P ; Babaei, M ; Sharif University of Technology
    John Wiley and Sons Inc  2021
    Abstract
    Data science as a flourishing interdisciplinary domain of computer and mathematical sciences is playing an important role in guiding the porous material research streams. In the present narrative review, we have examined recent trends and issues in data-driven methods used in the image-based porous material research studies relevant to water resources researchers and scientists. Initially, the recent trends in porous material data-related issues have been investigated through search engine queries in terms of data source, data storage hub, programing languages, and software packages. Subsequent to a diligent analysis of the existing trends, a review of the common concepts of porous material... 

    Multiple-relaxation time color-gradient lattice Boltzmann model for simulating contact angle in two-phase flows with high density ratio

    , Article European Physical Journal Plus ; Volume 134, Issue 8 , 2019 ; 21905444 (ISSN) Sheikholeslam Noori, S. M ; Taeibi Rahni, M ; Shams Taleghani, S. A ; Sharif University of Technology
    Springer Verlag  2019
    Abstract
    The contact line dynamics is an important phenomenon in natural and industrial processes and is still a challenging problem. The complexity of this problem in computational simulations is much more than theoretical and experimental works. In this paper, a color-gradient (CG) lattice Boltzmann method (LBM) for simulating wetting phenomena and the dynamics of contact line in two-phase flows with very high density-ratio (∼ 1000 was used. This method applies a multi-relaxation time (MRT) collision operator to enhance the stability of numerical scheme. Both static and dynamic contact angles were enforced at the wall through geometrical wetting boundary condition. Note, the main nobility of this... 

    Numerical analysis of droplet motion over a flat plate due to surface acoustic waves

    , Article Microgravity Science and Technology ; Volume 32, Issue 4 , 2020 , Pages 647-660 Sheikholeslam Noori, S. M ; Taeibi Rahni, M ; Shams Taleghani, S. A ; Sharif University of Technology
    Springer  2020
    Abstract
    Micro-scale systems have gained considerable attention in recent years and a large amount of researches have been done in this field. In this study, the hydrodynamic interference of a droplet is comprehensively investigated under surface acoustic waves. This paper reveals the effects of some control parameters such as wave amplitude and wave frequency on the dynamical behavior of droplet. For these purposes, a two-dimensional multiple-relaxation-time color-gradient model lattice Boltzmann method is developed. This model is first validated by dynamical behaviors of a droplet subjected to shear flow. Moreover, displacement of a droplet affected by surface acoustic waves is comprehensively... 

    Impact crushing behavior of foam-filled paraboloid shells using numerical and experimental methods

    , Article Scientia Iranica ; Volume 24, Issue 4 , 2017 , Pages 1912-1921 ; 10263098 (ISSN) Shams, S ; Haddadpour, H ; Tuzandejani, H ; Hosseini, S. A. A ; Vatanparast, M ; Zahab, S ; Sharif University of Technology
    Sharif University of Technology  2017
    Abstract
    This paper deals with the dynamic response and energy absorption of foam-filled aluminum parabolic tubes under axial impact loading. The numerical crush analysis of empty and foam-filled tubes is performed using non-linear finite element techniques. The effects of geometrical (wall thickness) and material parameters (foam density and Young's relaxation modulus) on the impact response and energy absorption capacity of foam-filled tube are investigated using numerical models. The results show that the foam properties have significant effect on the crushing behavior, force and impact acceleration magnitude, and energy absorption capacity. Furthermore, there is a critical foam density beyond... 

    Conformational Substates of Wild Type and Mutant (V68N) Myoglobin-CO

    , M.Sc. Thesis Sharif University of Technology Shams, Hengameh (Author) ; Ejtehadi, Mohammad Reza (Supervisor)
    Abstract
    Folded protein experience several conformational substates. Each substate reperesents a minimum in the free energy surface of the system. Since Myoglobin is the smallest protein that can reversibly bind to gas molecules and, it can be used as prototype for more complex systems.IR pecrtum of CO inside of myolgobin shows that distinct conformational substates can occur. It was shown that Histidine residue inside heme pocket plays an essential rolle in structural properties of substates. In this study, we used molecular dynamice simulation together with umbrella sampling method to obtain free energy profile of MbCO system. The configuration of distal Histidine (His64), CO and Heme is studied... 

    Assessing the effect of inattention-related error and anger in driving on road accidents among Iranian heavy vehicle drivers

    , Article IATSS Research ; 2020 Shams, Z ; Naderi, H ; Nassiri, H ; Sharif University of Technology
    Elsevier B.V  2020
    Abstract
    Extensive studies have examined the effect of variables such as demographic characteristics, insomnia, and working conditions of drivers individually on inattention-related error as well as expression of anger in driving. Nevertheless, so far no study has tested the concurrent effect of these factors on crashes. This study has dealt with indirect investigation of the effect of variables including demographic characteristics, insomnia, and working conditions of drivers on inattention-related error and expression of anger in driving (as mediation model). Next, the effect of these two variables on the probability of incidence of road crashes has been assessed among truck drivers. For this... 

    Assessing the effect of inattention-related error and anger in driving on road accidents among Iranian heavy vehicle drivers

    , Article IATSS Research ; Volume 45, Issue 2 , 2021 , Pages 210-217 ; 03861112 (ISSN) Shams, Z ; Naderi, H ; Nassiri, H ; Sharif University of Technology
    Elsevier B.V  2021
    Abstract
    Extensive studies have examined the effect of variables such as demographic characteristics, insomnia, and working conditions of drivers individually on inattention-related error as well as expression of anger in driving. Nevertheless, so far no study has tested the concurrent effect of these factors on crashes. This study has dealt with indirect investigation of the effect of variables including demographic characteristics, insomnia, and working conditions of drivers on inattention-related error and expression of anger in driving (as mediation model). Next, the effect of these two variables on the probability of incidence of road crashes has been assessed among truck drivers. For this...