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    Blood Supply Chain Robust Network Design Model for the Supply of Blood in Disaster

    , M.Sc. Thesis Sharif University of Technology Allahyari Emamzadeh, Yasin (Author) ; Haji, Alireza (Supervisor)
    Abstract
    This Thesis presents a robust network design model for supplying blood during and after an earthquake disaster. A two stage optimization model based on several real-world scenarios is developed. The purpose of this research is to locate and allocate fixed and mobile facilities in probabilistic situation, in which Tehran city with 22 districts is considered as a case study. This model can be categorized as a probabilistic model which demand and supply rate for blood and its derivatives is uncertain. Furthermore the blood transition between different blood types and conversion to its derivatives such as Platelet and plasma are involved in the proposed model. The supply chain for blood consists... 

    A fuzzy based model coordination for two-level optimal control of robot manipulators

    , Article Proceedings - International Conference on Tools with Artificial Intelligence, ICTAI, 9 November 2015 through 11 November 2015 ; Volume 2016-January , 2016 , Pages 1122-1128 ; 10823409 (ISSN) ; 9781509001637 (ISBN) Mollaie Emamzadeh, M ; Sadati, N ; Sharif University of Technology
    IEEE Computer Society  2016
    Abstract
    In this paper, a new fuzzy based Model Coordination (F-MC) strategy is proposed for hierarchical control of large-scale systems (LSS). To solve the overall problem with a two-level optimal control strategy, we first decompose the system into several sub-systems at the first level. Then, at the second level, a fuzzy coordinator will be used to predict the interaction between subsystems. The proposed fuzzy based coordination approach is applicable to all types of LSS. Although in this paper, an optimal control of a 2DOF robot manipulator, as a LSS, will be considered. The obtained results are compared with the centralized optimization  

    A novel fuzzy reinforcement learning approach in two-level intelligent control of 3-DOF robot manipulators

    , Article 2007 IEEE Symposium on Approximate Dynamic Programming and Reinforcement Learning, ADPRL 2007, Honolulu, HI, 1 April 2007 through 5 April 2007 ; 2007 , Pages 20-25 ; 1424407060 (ISBN); 9781424407064 (ISBN) Mollaie Emamzadeh, M ; Sadati, N ; Sharif University of Technology
    2007
    Abstract
    In this paper, a fuzzy coordination method based on Interaction Prediction Principle (IPP) and Reinforcement Learning is presented for the optimal control of robot manipulators with three degrees-of-freedom. For this purpose, the robot manipulator is considered as a two-level large-scale system where in the first level, the robot manipulator is decomposed into several subsystems. In the second level, a fuzzy interaction prediction system is introduced for coordination of the overall system where a critic vector is also used for evaluating its performance. The simulation results on using the proposed novel approach ,for optimal control of robot manipulators show its effectiveness and... 

    Controlling the flow-induced oscillations of a flexible cantilever beam using a plasma actuator

    , Article Physics of Fluids ; Volume 35, Issue 2 , 2023 ; 10706631 (ISSN) Allahyari, M ; Moosavi, A ; Sharif University of Technology
    American Institute of Physics Inc  2023
    Abstract
    We study the dynamics of flow over a flexible cantilever beam and explore the effect of the plasma actuators located at the upper and lower end edges of the beam to control the flow-induced vibration of the beam. For this purpose, three-dimensional simulations are performed at various Reynolds numbers for three cases including simple beam, beam without the plasma actuators, and beam with the plasma actuators. The results show that in comparison with the simple beam, the beam with the plasma actuators reduces the displacement of the tip by 33% and 18% at Reynolds numbers Re = 200 and 300, respectively. The plasma actuators cause a monotonic oscillation and a regular vortex street with... 

    Effect of Surface Structure on Drag Reduction

    , M.Sc. Thesis Sharif University of Technology Allahyari, Mostafa (Author) ; Moosavi, Ali (Supervisor)
    Abstract
    This project studies the effects of different blade and different velocity fields on reducing drag coefficient. A numerical simulation was set up for a circular cylinder to represent the effects of blade on reducing drag. In this study, velocity, density and the cylinder diameter were constant and different viscosities were selected for different regime flows. The computational fluid dynamic programmer FLUENT was used to simulate results for this project. Arrays of cylinders were set up to see the changes in velocity profiles and drag coefficients for a range of Re. In this study, I studied three cases of setting up blade and concentrated on friction drag coefficient and pressure drag... 

    An Investigation on Counter Current Flow Limitation (CCFL) in Hot Leg of Boushehr Nuclear Power Plant Using CFX

    , M.Sc. Thesis Sharif University of Technology Allahyari, Abdolhasib (Author) ; Ghaffari, Mohsen (Supervisor)
    Abstract
    This research aims to numerically investigate the Counter-Current Flow Limitation (CCFL) phenomenon in the hot leg of the Bushehr Nuclear Power Plant, with a focus on its unique Emergency Core Cooling System (ECCS) design. To achieve this, Computational Fluid Dynamics (CFD) was utilized through the commercial software ANSYS CFX. A two-stage methodology was employed: Initially, the numerical model was validated against experimental data from the TOPFLOW facility to ensure its predictive accuracy for two-phase flow phenomena. Subsequently, the validated model was used to simulate the CCFL phenomenon in the real, full-scale geometry of the Bushehr power plant's hot leg, with boundary conditions... 

    Two-Level Intelligent Control of Multiple Robotic Arms

    , Ph.D. Dissertation Sharif University of Technology Mollaie Emamzadeh, Mohammad (Author) ; Sadati, Naser (Supervisor)
    Abstract
    This thesis presents a fuzzy-based interaction prediction approach (F-IPA) for two-level optimal control of large-scale systems. The design procedure uses a decomposition/coordination framework of hierarchical structures. At the first level, the system is decomposed into subsystems for which subproblems are formed. At the second level, a fuzzy coordinator is used to predict the coordination parameters needed to coordinate the solutions of the first level subproblems. The fuzzy coordinator uses a critic vector to evaluate its performance and learn its parameters by minimizing an energy function. The proposed control scheme is implemented on a two-degrees-of-freedom (2DOF) model of robot... 

    Long gradient mode and large-scale structure observables

    , Article Physical Review D ; Volume 95, Issue 6 , 2017 ; 24700010 (ISSN) Allahyari, A ; Firouzjaee, J. T ; Sharif University of Technology
    American Physical Society  2017
    Abstract
    We extend the study of long-mode perturbations to other large-scale observables such as cosmic rulers, galaxy-number counts, and halo bias. The long mode is a pure gradient mode that is still outside an observer's horizon. We insist that gradient-mode effects on observables vanish. It is also crucial that the expressions for observables are relativistic. This allows us to show that the effects of a gradient mode on the large-scale observables vanish identically in a relativistic framework. To study the potential modulation effect of the gradient mode on halo bias, we derive a consistency condition to the first order in gradient expansion. We find that the matter variance at a fixed physical... 

    Fuzzy-based interaction prediction approach for hierarchical control of large-scale systems

    , Article Fuzzy Sets and Systems ; Volume 329 , 2017 , Pages 127-152 ; 01650114 (ISSN) Emamzadeh, M. M ; Sadati, N ; Gruver, W. A ; Sharif University of Technology
    2017
    Abstract
    This paper presents a fuzzy-based interaction prediction approach (F-IPA) for two-level optimal control of large-scale systems. The design procedure uses a decomposition/coordination framework of hierarchical structures. At the first level, the system is decomposed into subsystems for which subproblems are formed. At the second level, a fuzzy coordinator is used to predict the coordination parameters needed to coordinate the solutions of the first level subproblems. The fuzzy coordinator uses a critic vector to evaluate its performance and learn its parameters by minimizing an energy function. The proposed control scheme is implemented on a two-degrees-of-freedom (2DOF) model of robot... 

    Investigation on the wear properties of Ti/TiC/TiN composite coatings prepared by powder cored wires through TIG method at nitrogen atmosphere on titanium substrate

    , Article Materials Research ; Volume 22, Issue 2 , 2019 ; 15161439 (ISSN) Kokabi, A. H ; Ammari Allahyari, A ; Sharif University of Technology
    Universidade Federal de Sao Carlos  2019
    Abstract
    In this present study, Tungsten Inert Gas (TIG) welding and powder filled cored wires with nitrogen shielding gas were utilized to produce TiC and TiN surface composite coatings on the titanium (Ti) sheet substrate. The TIG procedure was done at same welding parameters for all of prepared samples. Phase analysis and microstructures were done by X-ray Diffraction (XRD), Energy-Dispersive X-ray Spectroscopy (EDS), Optical Microscopy (OM) and Scanning Electron Microscopy (SEM). The obtained results from XRD and EDS demonstrated that the presence of crystalline phases of TiC, TiN and Ti. SEM and OM exhibited formation of the spherical and dendritic TiC particles in a martensitic matrix and also,... 

    Introducing a method for calculating water saturation in a carbonate gas reservoir

    , Article Journal of Natural Gas Science and Engineering ; Volume 70 , 2019 ; 18755100 (ISSN) Movahhed, A ; Nabi Bidhendi, M ; Masihi, M ; Emamzadeh, A ; Sharif University of Technology
    Elsevier B.V  2019
    Abstract
    Cementation factor greatly affects water saturation estimation. Factors such as depositional environment, diagenesis and depositional architecture make the estimation of water saturation a big challenge in carbonate reservoirs. The current study is introduced a method for calculating cementation factor in Archie formula. First, (MRGC) technique was applied on the (NMR) logging parameters along with (NDS) data to obtain the optimum number of clustering. After that, fuzzy logic method was applied on conventional log parameters obtained from the wells without any NMR log data. In the third part of the study, a novel crossplot introduced including compressional to shear-wave velocity ratio... 

    Gravitational collapse in the AdS background and the black hole formation

    , Article International Journal of Modern Physics D ; Volume 25, Issue 1 , 2016 ; 02182718 (ISSN) Allahyari, A ; Firouzjaee, J. T ; Mansouri, R ; Sharif University of Technology
    World Scientific Publishing Co. Pte Ltd  2016
    Abstract
    We study the time evolution of the Misner-Sharp mass and the apparent horizon for gravitational collapse of a massless scalar field in the AdS5 spacetime for both cases of narrow and broad waves by numerically solving the Einstein's equations coupled to a massless scalar field. This is done by relying on the full dynamics of the collapse including the concept of the dynamical horizon. It turns out that the Misner-Sharp mass is everywhere constant except for a rapid change across a thin shell defined by the density profile of the collapsing wave. By studying the evolution of the apparent horizon, indicating the formation of a black hole at different times we see how asymptotically an event... 

    Nonlinear phenomena in general relativity

    , Article European Physical Journal Plus ; Volume 133, Issue 4 , April , 2018 ; 21905444 (ISSN) Allahyari, A ; Taghizadeh Firouzjaee, J ; Mansouri, R ; Sharif University of Technology
    Springer Verlag  2018
    Abstract
    The perturbation theory plays an important role in studying structure formation in cosmology and post-Newtonian physics, but not all phenomena can be described by the linear perturbation theory. Thus, it is necessary to study exact solutions or higher-order perturbations. Specifically, we study black hole (apparent) horizons and the cosmological event horizon formation in the perturbation theory. We emphasize that in the perturbative regime of the gravitational potential these horizons cannot form in the lower order. Studying the infinite plane metric, we show that, to capture the cosmological constant effect, we need at least a second-order expansion. © 2018, Società Italiana di Fisica and... 

    Analysis of near well-bore behavior of gas condensate reservoir in production stage

    , Article Petroleum Science and Technology ; Volume 30, Issue 24 , 2012 , Pages 2594-2603 ; 10916466 (ISSN) Allahyari, M ; Aminshahidy, B ; Sanati, A ; Taghikhani, V ; Sharif University of Technology
    2012
    Abstract
    The formation of condensate banking in the near well-bore region will lead to the reduction in gas relative permeability and loss of well deliverability. This loss is investigated by conducting a series of fine grid numerical compositional simulation with the gas condensate and dry gas reservoir data. Also, a method for calculation of condensate blockage skin factor is introduced in which the skin factor is calculated using dry gas and gas condensate simulation production data. The authors also found that absolute permeability and pressure drawdown of the producing well have significant influence on the well gas deliverability and condensate blockage skin factor  

    Primordial black holes in linear and non-linear regimes

    , Article Journal of Cosmology and Astroparticle Physics ; Volume 2017, Issue 6 , 2017 ; 14757516 (ISSN) Allahyari, A ; Firouzjaee, J. T ; Abolhasani, A. A ; Sharif University of Technology
    2017
    Abstract
    We revisit the formation of primordial black holes (PBHs) in the radiation-dominated era for both linear and non-linear regimes, elaborating on the concept of an apparent horizon. Contrary to the expectation from vacuum models, we argue that in a cosmological setting a density fluctuation with a high density does not always collapse to a black hole. To this end, we first elaborate on the perturbation theory for spherically symmetric space times in the linear regime. Thereby, we introduce two gauges. This allows to introduce a well defined gauge-invariant quantity for the expansion of null geodesics. Using this quantity, we argue that PBHs do not form in the linear regime irrespective of the... 

    An Asymptotically AdS Blackhole with Scalar Field and Its Propeties

    , M.Sc. Thesis Sharif University of Technology Allahyari, Alireza (Author) ; Mansouri, Reza (Supervisor) ; Taghizadeh Firouzjaee, Javad (Co-Advisor)
    Abstract
    There has been a growing interest in studying asymptotically AdS space times given the AdS/CFT conjecture. Among different models finding the one which decribes broader phenomena is important.The importance of a dynamical metric stems from the fact that one can see thermalization in its dual description. We introduce a dynamical metric and study apparent horizon formation and energy evolution as well. We plot its appparent horizion curve and show that it aproaches the static limit within our numerical accuracy. We then review quasi-normal modes of this space time  

    The air quality of Tehran underground railway transit system

    , Article BHR Group - 14th International Symposium on Aerodynamics and Ventilation of Tunnels, 11 May 2011 through 13 May 2011 ; May , 2011 , Pages 551-561 ; 9781855981232 (ISBN) Jafari, M. J ; Abbasspour, M ; Mansoori, N ; Moattar, F ; Nouri, N ; Allahyari, M ; Sharif University of Technology
    2011
    Abstract
    This study examines the air quality on line 1 and 2 of Tehran underground metro. The total suspended particulate (TSP), PM10, PM2.5, PM1, CO2, NO, NO2, SO2, relative humidity and air temperature were measured. An integrated air quality index was also calculated for each location. The results revealed that, PMlO, PM2.5, and SO2 concentrations are higher than their environmental standard levels. The in station CO2 levels are higher while its' in train levels are lower than environmental permissible level. The air quality index showed that the in-train air quality is more acceptable than the instation air quality  

    A size-dependent generalized thermoelasticity theory for thermoelastic damping in vibrations of nanobeam resonators

    , Article International Journal of Structural Stability and Dynamics ; Volume 23, Issue 12 , 2023 ; 02194554 (ISSN) Jalil, A.T ; Saleh, Z. M ; Imran, A. F ; Yasin, Y ; Ruhaima, A. A. K ; Gatea, M. A ; Esmaeili, S ; Sharif University of Technology
    World Scientific  2023
    Abstract
    Thermoelastic damping (TED) has been discerned as a definite source of intrinsic energy loss in miniaturized mechanical elements. The size-dependent structural and thermal behavior of these small-sized structures has been proven through experimental observations. As a first attempt, this article exploits nonlocal strain gradient theory (NSGT) and nonlocal dual-phase-lag (NDPL) heat conduction model simultaneously to acquire a mathematical formulation and analytical solution for TED in nanobeams that can accommodate size effect into both structural and heat transfer fields. For this purpose, the coupled equations of motion and heat conduction are firstly extracted via NSGT and NDPL model.... 

    Relativistic and Nonlinear Lffects in Large Scale Structures

    , Ph.D. Dissertation Sharif University of Technology Allahyari Sadeghabadi, Alireza (Author) ; Mansouri, Reza (Supervisor) ; Taghizadeh Firouzjaee, Javad (Co-Supervisor)
    Abstract
    Although general relativity is the underlying assumption in modern cosmology, there are still many simplifying assumptions neglecting higher order general relativistic effects. Given the precision cosmology and future surveys and the amount of data on large scales, higher order relativistic effects are to be taken into account. We will consider two categories of relativistic effects on large scale structures. First, the inhomogeneities between the source and the observer may lead to observable effects neglected so far. As future surveys will probe the universe on large scales, these effects have been the focus of recent studies. The observables being defined first, are cosmic rulers and... 

    Investigation of Mass Transfer Coefficients in Lithium Liquid-Liquid Extraction Process in Batch and Continuous Modes (Microchannel)

    , M.Sc. Thesis Sharif University of Technology Bahadri, Mohammad Mehdi (Author) ; Otokesh, Mohammad (Supervisor) ; Amari Allahyari, Sareh (Supervisor) ; Zaheri, Parisa (Co-Supervisor)
    Abstract
    Lithium is a soft, silvery-white alkali metal that is recognized as the lightest metal and the least dense solid element. The increasing demand for lithium, driven by the global shift towards electrification and sustainable energy solutions, has transformed this material into a crucial resource in the modern economy. Lithium has applications in various industries, including the nuclear industry. 6Li is used for the production of tritium, and 7Li, in the form of 7LiOH, is used to adjust the pH in light water reactors and as an anti-corrosion compound in fission reactors. In this study, the extraction of lithium from the aqueous phase using a Y-shaped microchannel was carried out, and the mass...