Search for: three-dimensional-model
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    Three-dimensional data transfer operators in plasticity using SPR technique with C0, C1 and C2 continuity

    , Article Scientia Iranica ; Volume 15, Issue 5 , 2008 , Pages 554-567 ; 10263098 (ISSN) Khoei, A. R ; Gharehbaghi, S. A ; Sharif University of Technology
    Sharif University of Technology  2008
    In this paper, the data transfer operators are developed in three-dimensional elasto-plasticity using the Superconvergent Patch Recovery (SPR) method. The transfer operators are defined for mapping of the state and internal variables between different meshes. The internal variables are transferred from Gauss points of old mesh to the nodal points. The variables are then transferred from the nodal points of old mesh to the nodal points of new mesh. Finally, the values are computed at the Gauss points of new mesh using their values at the nodal points. Aspects of the transfer operators are presented in a three-dimensional superconvergent path recovery technique, based on C0, C1 and C2... 

    Investigating the Behavior of 3D Irregular Steel Structures with Seismic Base Isolation under Multi-Directional Excitations and Predicting Results by Using the Endurance Time Method

    , M.Sc. Thesis Sharif University of Technology Zarbilinezhad, Milad (Author) ; Esmail Pourestekanchi, Homayoon (Supervisor)
    This research has been performed with the aim of gaining familiarity with various types of seismic isolation systems, their unique features and numerous advantages, factors affecting their performance and finally their modelling and design. Despite the advantages of seismic isolation systems as control instruments, but where there is not enough information on the involved parameters in the performance of these systems, there is possibility of unpredictable behavior of the structures. Hence, considering the extent and influence of each parameter involved in the performance of the isolators, a parametric study is performed utilizing the 3D models under multi-directional excitations, using the... 

    MODSharp: Regional-scale numerical model for quantifying groundwater flux and contaminant discharge into the coastal zone

    , Article Environmental Modelling and Software ; Volume 22, Issue 9 , 2007 , Pages 1307-1315 ; 13648152 (ISSN) Ataie Ashtiani, B ; Sharif University of Technology
    In this paper the development of a quasi-three-dimensional numerical model that can be used for quantifying groundwater inputs and associated contaminant discharged from coastal aquifers into the coastal zone at a regional scale is presented. The present model is called MODSharp. In order to handle problems at a regional scale, the sharp interface approach which is used for conceptualising seawater intrusion, is applied to this model. This model can be used for the simulation of groundwater flow and contaminant transport in layered coastal aquifers at a regional scale. The method of characteristics is used to solve the advection-dispersion equation, which governs contaminant transport in... 

    Effects of geometric imperfections on the performance of Sahand cooling tower

    , Article 10th East Asia-Pacific Conference on Structural Engineering and Construction, EASEC 2010, Bangkok, 3 August 2006 through 5 August 2006 ; Volume 5 , 2006 , Pages 331-338 ; 9748257207 (ISBN); 9789748257204 (ISBN) Riahi, H. T ; Haghighi, B ; Sharif University of Technology
    School of Engineering and Technology  2006
    During construction of one of the Sahand cooling towers due to slip forming performance some imperfections were raised mostly between elevation of +30 and +40 meter. It was evaluated that some points of the shell should be repaired. In constructing the cooling tower from elevation +40 to +60 meter these imperfections were removed and the cooling tower was constructed with no problem until the elevation +130 meter. In this paper reasons of generation of geometric imperfections in Sahand cooling tower are clearly shown and possible ways for preventing them are discussed. Applied repairing method for Sahand cooling tower is explained in detail. Geometrical imperfections of the constructed... 

    Multi-channel electrocardiogram denoising using a Bayesian filtering framework

    , Article 2006 Computers in Cardiology, CIC, Valencia, 17 September 2006 through 20 September 2006 ; Volume 33 , 2006 , Pages 185-188 ; 02766574 (ISSN); 1424425328 (ISBN); 9781424425327 (ISBN) Sameni, R ; Shamsollahi, M. B ; Jutten, C ; Sharif University of Technology
    In some recent works, model-based filtering approaches have been proved as effective methods for extracting ECG signals from single channel noisy recordings. The previously developed methods, use a highly realistic nonlinear ECG model for the construction of Bayesian filters. In this work, a multi-channel extension of the previous approach is developed, by using a three dimensional model of the cardiac dipole vector. The results have considerable improvement compared with the single channel approach. The method is hence believed to be applicable to low SNR multi-channel recordings  

    Turn-to-Turn Fault Detection in Power Transformers in the Presence of Inrush Current

    , M.Sc. Thesis Sharif University of Technology Fallah Mollamahmod, Mahdi (Author) ; Hajipour, Ehsan (Supervisor)
    One of the most critical equipments in power grids are power transformers, which are vulnerable to damage due to the possibility of faults in its various components. A very common category of such faults is turn-to-turn fault in its winding. This fault initiates by the aging of the winding insulation with a short circuit of several adjacent loops to each other and if it is not detected quickly by the transformer protection, it will spread rapidly and can lead to irreparable failure in the transformer. Traditionally, turn-to-turn fault should be detected by mechanical pressure relays, however, due to the poor performance of these relays in the rapid detection of this type of fault, in the... 

    Seismic behavior of a dolphin-type berth subjected to liquefaction induced lateral spreading: 1g large scale shake table testing and numerical simulations

    , Article Soil Dynamics and Earthquake Engineering ; Volume 140 , 2021 ; 02677261 (ISSN) Kavand, A ; Haeri, S. M ; Raisianzadeh, J ; Sadeghi Meibodi, A ; Afzal Soltani, S ; Sharif University of Technology
    Elsevier Ltd  2021
    The effects of liquefaction induced lateral spreading on the piles of a dolphin-type berth were investigated using 1 g large scale shake table testing accompanied by numerical simulations. For this purpose, various aspects of the response of the soil and the pile group to lateral spreading were considered. The results indicated that large bending moments were induced in the piles during lateral spreading and the downslope piles of the group received greater bending moments than the upslope one. The monotonic components of bending moments in the piles were reasonably predicted by the displacement based numerical approach using p-y springs when they were properly tuned for strength reduction... 

    Optimization of a novel photovoltaic thermal module in series with a solar collector using Taguchi based grey relational analysis

    , Article Solar Energy ; Volume 215 , 2021 , Pages 492-507 ; 0038092X (ISSN) Kazemian, A ; Parcheforosh, A ; Salari, A ; Ma, T ; Sharif University of Technology
    Elsevier Ltd  2021
    The solar collectors absorb solar irradiation and then produce thermal energy; however, they cannot generate electrical power. Electricity and thermal energy can be produced by the photovoltaic thermal module, simultaneously, while the outlet temperature of the photovoltaic thermal module is not usually high enough to provide thermal requirements of a building such as hot water or space heating. This work proposes a novel compound system created by the connection of a solar collector in series with a photovoltaic thermal module to resolve the issue of low outlet temperature in the photovoltaic thermal module and lack of electrical power in solar collectors. To examine the feasibility of this... 

    Numerical study to evaluate the important parameters affecting the hydrodynamic performance of manta ray's in flapping motion

    , Article Applied Ocean Research ; Volume 109 , 2021 ; 01411187 (ISSN) Safari, H ; Abbaspour, M ; Darbandi, M ; Sharif University of Technology
    Elsevier Ltd  2021
    Manta ray swimming or bio-inspiration propulsion system, as a special type of marine propulsion system, is used for submersible vehicles that require high-speed maneuverability and stability, such as glider and AUV. In a manta ray swimming, the thrust force is generated by a couple of undulation and oscillation of wing, so that the direction of undulation wave and oscillation is upright and perpendicular to the direction of thrust force, respectively. It is possible to combine these two movement modes (flapping motion) on the three-dimensional model without considering the effects of wing twisting and flexibility to simplify and better understand the physical behaviors or special study of... 

    Proposing a general formula to calculate the critical velocities in tunnels with different cross-sectional shapes

    , Article Tunnelling and Underground Space Technology ; Volume 110 , 2021 ; 08867798 (ISSN) Savalanpour, H ; Farhanieh, B ; Afshin, H ; Sharif University of Technology
    Elsevier Ltd  2021
    Among the parameters affecting the critical velocity in tunnel fires, the tunnel cross-sectional shape could significantly affect the tunnel fire characteristics, mainly due to the wall-bounded physics of the tunnel fire. Previously, the effects of the cross-sectional geometry of the tunnel were calculated using the non-dimensional analysis and hydraulic height of the tunnel. The dimensionless analysis using hydraulic height calculates only the effects of the tunnel sizes and does not capture the effects of the shape of the tunnel cross-section. Developing a 3D computational fluid dynamics tool using the body-fitted grids, the critical velocities are calculated for the 7 different... 

    A hybrid of statistical and conditional generative adversarial neural network approaches for reconstruction of 3D porous media (ST-CGAN)

    , Article Advances in Water Resources ; Volume 158 , 2021 ; 03091708 (ISSN) Shams, R ; Masihi, M ; Bozorgmehry Boozarjomehry, R ; Blunt, M. J ; Sharif University of Technology
    Elsevier Ltd  2021
    A coupled statistical and conditional generative adversarial neural network is used for 3D reconstruction of both homogeneous and heterogeneous porous media from a single two-dimensional image. A statistical approach feeds the deep network with conditional data, and then the reconstruction is trained on a deep generative network. The conditional nature of the generative model helps in network stability and convergence which has been optimized through a gradient-descent-based optimization method. Moreover, this coupled approach allows the reconstruction of heterogeneous samples, a critical and serious challenge in conventional reconstruction methods. The main contribution of this work is to... 

    3D steady state seepage analysis of embankment dams

    , Article Electronic Journal of Geotechnical Engineering ; Volume 10 F , 2005 ; 10893032 (ISSN) Soleimanbeigi, A ; Jafarzadeh, F ; Sharif University of Technology
    Steady state seepage analysis of embankment dams is one of the most significant stages in the designing process. Currently, most seepage modeling of embankment dams is performed in two dimensions, often for the highest section, which include several simplifications. In this way, the effect of watertight elements such as grouting curtains in side abutments as well as their material properties is not taken into account in seepage analysis results. Especially if the dam is located in a narrow valley or the effect of existing faults beneath the dam is to be investigated, the results of the two-dimensional seepage analysis differ from those of three-dimensional (3D). In this paper, the... 

    3d Design of a Microfluidic Chip for Anticancer Drugs Screening

    , M.Sc. Thesis Sharif University of Technology Hashemi, Maryam Sadat (Author) ; Mashayekhan, Shohreh (Supervisor) ; Saadatmand, Maryam (Supervisor)
    Nowadays, advanced and inexpensive pre-clinical methods for investigating the effects of anti-cancer drugs are expanding. One of the latest three-dimensional laboratory modeling for evaluating the effects of drugs is the use of tumor-on-chip technology, which actually models the physiological system of the body through three-dimensional scaffolds, multicellular cultures, and shaped vascular systems. In this study, three-dimensional culture of cancer cells was performed in the form of spheroids. A chip of U-shaped microstructures with and without gaps was used to trap cells and form cancer spheroids. We simulated the simultaneous effect of drug and oxygen concentration distribution inside the...