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    Non-Relativistic Conformal Symmetries; Infinite Extensions and Logarithmic Representation

    , Ph.D. Dissertation Sharif University of Technology Hosseiny Esfidvajani, Ali (Author) ; Rouhani, Shahin (Supervisor)
    Abstract
    We study different aspects of non-relativistic conformal symmetries. Schrodinger and Galilean Conformal Algebra (GCA) are reviewed extensively. We as well study possible extensions of non-relativistic conformal symmetries. We find a new class of infinite dimensional non-relativistic conformal symmetries in 2+1. We study logarithmic representation of Schrodinger symmetry. As well we utilize contraction approach and obtain both ordinary and logarithmic representations of GCA. Finally we investigate some aspects of logarithmic GCA in the context of holography principle  

    On holographic realization of logarithmic Galilean conformal algebra

    , Article Journal of Mathematical Physics ; Volume 52, Issue 9 , 2011 ; 00222488 (ISSN) Hosseiny, A ; Naseh, A ; Sharif University of Technology
    2011
    Abstract
    We study two-dimensional logarithmic Galilean conformal algebra (LGCA) by making use of a contraction of topologically massive gravity at critical point. We observe that using a naive contraction at the critical point fails to give a well defined theory, though contracting the theory while we are approaching the critical point leads to a well behaved expression for two point functions of the energy-momentum tensors of LGCA  

    Fractional Galilean symmetries

    , Article Nuclear Physics B ; Volume 910 , 2016 , Pages 336-345 ; 05503213 (ISSN) Hosseiny, A ; Rouhani, S ; Sharif University of Technology
    Elsevier  2016
    Abstract
    We generalize the differential representation of the operators of the Galilean algebras to include fractional derivatives. As a result a whole new class of scale invariant Galilean algebras are obtained. The first member of this class has dynamical index z=2 similar to the Schrödinger algebra. The second member of the class has dynamical index z=3/2, which happens to be the dynamical index Kardar–Parisi–Zhang equation  

    Affine extension of Galilean conformal algebra in 2+1 dimensions

    , Article Journal of Mathematical Physics ; Volume 51, Issue 5 , Sep , 2010 ; 00222488 (ISSN) Hosseiny, A ; Rouhani, S ; Sharif University of Technology
    2010
    Abstract
    We show that a class of nonrelativistic algebras including noncentrally extended Schrödinger algebra and Galilean conformal algebra (GCA) has an affine extension in 2+1 hitherto unknown. This extension arises out of the conformal symmetries of the two dimensional complex plane. We suggest that this affine form may be the symmetry that explains the relaxation of some classical phenomena toward their critical point. This affine algebra admits a central extension and maybe realized in the bulk. The bulk realization suggests that this algebra may be derived by looking at the asymptotic symmetry of an Anti-de Sitter (AdS) theory. This suggests that AdS/CFT (conformal field theory) duality may... 

    Logarithmic correlators in nonrelativistic conformal field theory

    , Article Journal of Mathematical Physics ; Volume 51, Issue 10 , 2010 ; 00222488 (ISSN) Hosseiny, A ; Rouhani, S ; Sharif University of Technology
    2010
    Abstract
    We show how logarithmic terms may arise in the correlators of fields which belong to the representation of the Schrödinger-Virasoro algebra or the affine Galilean conformal algebra (GCA). We show that in GCA, only scaling operator can have a Jordan form and rapidity cannot. We observe that in both algebras, logarithmic dependence appears along the time direction alone  

    Introducing a Simulation-Based Model to Improve the Design and Layout of Workstations Inside Airport Terminals in Iran

    , M.Sc. Thesis Sharif University of Technology Amini Esfidvajani, Amin Mohammad (Author) ; Alvanchi, Amin (Supervisor)
    Abstract
    The airport terminal is difficult to plan and design due to the different components and the intricate complexity of its parts. At the airport terminal, we face a queue system which simulation is always a good way to analyze. In addition, computer simulation using modern softwares with the capability to model different types of systems, including the airport terminal, while being less realistic than analytical models, is less costly than operational Exercise.In this study, a supportive approach for better and specific management of Iranian airport terminal buildings with discrete-event simulation is proposed, considering the need for managing the airport terminals building in the country and... 

    Modelling of organic removal in a Moving Bed Biofilm Reactor (MBBR)

    , Article Scientia Iranica ; Volume 9, Issue 1 , 2002 , Pages 53-58 ; 10263098 (ISSN) Hosseiny, S. H ; Borghei, S. M ; Sharif University of Technology
    Sharif University of Technology  2002
    Abstract
    In this paper, a new Moving Bed Biofilm Reactor (MBBR) has been developed, in which biomass is attached to small plastic elements that move freely in the bioreactor. The biofilm carrier elements, shaped like small corrugated cylinders, are made of polyethylene with a density of 0.95 gr/cm3 slightly lower than the density of water, allowing them to circulate with the currents in the reactor. The unit was tested under different organic loads and the substrate loading removal rate was compared with predictions of the Kincannon-Stover and Monod models. In this experiment, the influent COD concentration was between 225 mg/l to 4370 mg/l. The Hydraulic Retention Time (HRT) was 24 hr and the... 

    Hysteresis of economic networks in an XY model

    , Article Physica A: Statistical Mechanics and its Applications ; Volume 513 , 2019 , Pages 644-652 ; 03784371 (ISSN) Hosseiny, A ; Absalan, M ; Sherafati, M ; Gallegati, M ; Sharif University of Technology
    Elsevier B.V  2019
    Abstract
    Many-body systems can have multiple equilibria. Though the energy of equilibria might be the same, still systems may resist to switch from an unfavored equilibrium to a favored one. In this paper we investigate occurrence of such phenomenon in economic networks. In times of crisis when governments intend to stimulate economy, a relevant question is on the proper size of stimulus bill. To address the answer, we emphasize the role of hysteresis in economic networks. In times of crises, firms and corporations cut their productions; now since their level of activity is correlated, metastable features in the network become prominent. This means that economic networks resist against the recovery... 

    Analysis of a Lamellar Inhomogeneity Via Repordusing Kernel Particle Method

    , M.Sc. Thesis Sharif University of Technology Raeis Hosseiny, Aydin (Author) ; Mohammadi Shodja, Hossein (Supervisor)
    Abstract
    Nowadays, the excellent technological applications of composites have attracted the attentions of industry and numerous scientists. They are advantageous for their high tensile modulus, strength, and promising electrical and thermal properties. In applying the approach of lamellar inhomogeneity to real composites, the micro-geometries of the reinforcement must be considered such that they can be approximated as limiting case of an ellipsoid. In vapor grown carbon nanofiber, the fiber may have a diameter of about 150nm and length of 10-20 µm [1]. The modulus of carbon nanofiber is normally in the range of 100-600 GPa and sometimes even higher, whereas the modulus of some polymers is usually... 

    Node Placement in a Wireless Sensor Networks with Genetic Algorithm

    , M.Sc. Thesis Sharif University of Technology Hosseiny Khamseh Motlagh, Atena (Author) ; Seifipour, Navid (Supervisor)
    Abstract
    Coverage rate is a critical criterion in all of communication networks. In this regard, there are many different methods for distribution of network particles duo to attain the most efficient region of coverage. This emerges from the limited ability of each networks particle both in range of communicate and power consumption. In this thesis an evolutionary method is introduced to how Wireless Sensor Networks (WSN) particles can be dispensed to have more reliable coverage rate. Using both static and mobile sensor packages to cover the desired area and used a cost function, coverage rate, the authors tried to maximize it to have an excellent performance of network. Then proposed algorithm is... 

    High performance fuzzy-Padé controllers: Introduction and comparison to fuzzy controllers

    , Article Nonlinear Dynamics ; Volume 71, Issue 1-2 , January , 2013 , Pages 141-157 ; 0924090X (ISSN) Abedinnasab, M. H ; Yoon, Y. J ; Saeedi Hosseiny, M. S ; Sharif University of Technology
    2013
    Abstract
    In this paper, a new highly convergent, efficient, and fast response control technique entitled as fuzzy-Padé control method is introduced. It provides a simple methodology to exploit the heuristic knowledge in controlling a system. Fuzzy-Padé controllers originate from a unification of heuristic knowledge expressed as the rule base, and Padé approximants. In this method, fuzzy singleton rules are used to generate the rule base. Accordingly, unknown parameters in the Padé approximant are determined using these rules. The fuzzy-Padé controllers possess certain advantages over fuzzy controllers, and they can be applied in situations where fuzzy controllers previously failed. To demonstrate the... 

    Quartic balance theory: Global minimum with imbalanced triangles

    , Article Physical Review E ; Volume 102, Issue 1 , 2020 Kargaran, A ; Ebrahimi, M ; Riazi, M ; Hosseiny, A ; Jafari, G. R ; Sharif University of Technology
    American Physical Society  2020
    Abstract
    Balance theory proposed by Heider for the first time modeled triplet interaction in a signed network, stating that relationships between two people, friendship or enmity, is dependent on a third person. The Hamiltonian of this model has an implicit assumption that all triads are independent, meaning that the type of each triad, being balanced or imbalanced, determined apart from the state of other triads. This independence forces the network to have completely balanced final states. However, there exists evidence indicating that real networks are partially balanced, raising the question of what is the mechanism preventing the system to be perfectly balanced. Our suggestion is to consider a... 

    Technical English for mechanical engineers

    , Book Alemi, Minoo ; Meghdari,Ali
    Sharif University Press  2014
    Abstract
    Local educational institutions produce in-house English for Specific Purpose (ESP) materials according to the curriculum policies designated and developed by the Ministry of Higher Education In Iran. To this end, this book aims to be used in the Iranian setting at the tertiary level for undergraduate students majoring in Mechanical Engineering. Moreover, the style of English usage in this ESP textbook is American.
    Regarding the content of the textbook, it has both thematic organizations in which the topics are relevant and includes sufficient treatment of the target language areas necessary for the students. The principle organizing approach of this textbook is theme-based. In addition,... 

    Feedback control of the neuro-musculoskeletal system in a forward dynamics simulation of stair locomotion [electronic resource]

    , Article Proc. of IMechE Part H: Journal of Engineering in Medicine ; 2009, Vol. 223, No. 6, pp. 663-675 Journal of NeuroEngineering and Rehabilitation ; Volume 11, Issue 1, 30 April 2014, Article number 78 Selk Ghafari, A. (Ali) ; Meghdari, Ali ; Vossough, Gholam Reza ; Sharif University of Technology
    Abstract
    The aim of this study is to employ feedback control loops to provide a stable forward dynamics simulation of human movement under repeated position constraint conditions in the environment, particularly during stair climbing. A ten-degrees-of-freedom skeletal model containing 18 Hill-type musculotendon actuators per leg was employed to simulate the model in the sagittal plane. The postural tracking and obstacle avoidance were provided by the proportional—integral—derivative controller according to the modulation of the time rate change of the joint kinematics. The stability of the model was maintained by controlling the velocity of the body's centre of mass according to the desired centre of... 

    Design and Construction of a Soft Actuated Exoskeleton for Hand Rehabilitation of Stroke Patients

    , M.Sc. Thesis Sharif University of Technology Razavi Zadehgan, Ali Akbar (Author) ; Ghafari, Ali (Supervisor) ; Meghdari, Ali (Supervisor)
    Abstract
    The main goal of this thesis is the design and development of a rehabilitation device for helping patients “to improve blood circulation” & retain and recover their abilities if possible that were lost during the stroke or a accident like that (my research in karaj/iran shows that it is possible by just movement of the specific body part). The focus is on hand in this thesis because Injuries to the hand are common and can be very debilitating since our hands are our primary means for interacting with our world. For rehabilitation in case of human hand there are several practices that should be done for patients either in home or in a rehabilitation center, time and money that is supposed to... 

    Silica chloride/wet SiO2 as a novel heterogeneous system for the deprotection of acetals under mild conditions [electronic resource]

    , Article Phosphorus, Sulfur, and Silicon and the Related Elements ; Volume 178:2667-2670, Issue 12, 2003 Mirjalili, B. F. (BiBi Fatemeh) ; Pourjavadi, Ali ; Zolfigol, Mohammad Ali ; Bamoniri, Abdolhamid
    Abstract
    A combination of silica chloride and wet SiO2 was used as an effective deacetalizating agent for the conversion of acetals to their corresponding carbonyl derivatives under mild and heterogeneous condition  

    Earthquake Branch

    , M.Sc. Thesis Sharif University of Technology Bagher Shemirani, Ali Reza (Author) ; Bakhshi, Ali (Supervisor)
    Abstract
    In the past few decades, shaking tables are widely used to evaluate system response of structures under seismic excitations. These devices are used without any fundamental research performed on a shaking table system as an entity model. In most of these studies for simplicity, it is assumed that there exist no considerable vibration and displacement around the shaking tables, and no attention is paid to the peripheral substances such as soil settled under the foundation.
    In this thesis, result of ambient vibration test on shaking table system (solid deck, concrete foundation and soil layer) has been presented. Precise sensors known as low frequency and high accuracy accelerometers have... 

    Selective synthesis of conjugated enynes from α-arylalkynols using LiCl-Acidic Al2O3 under solvent-free conditions [electronic resource]

    , Article Journal of Chemical Research ; Volume 2002, Number 8, 1 August 2002, pp. 378-380(3) Pourjavadi, A. (Ali) ; Bagheri Marandi, Gholam
    Abstract
    Free Content Selective synthesis of conjugated enynes from α-arylalkynols using LiCl-Acidic Al2O3 under solvent-free conditions  

    Selective preparation of fluorescent 1,8-naphthalimides using acidic alumina under microwave irradiation [electronic resource]

    , Article Journal of Chemical Research ; 01/2001; 2001(11):485-487 Pourjavadi, A. (Ali) ; Bagheri Marandi, Gholam
    Abstract
    7H-benzimidazo[2,1-a]benz[de]isoquinolin-7-one compounds were prepared in a selective manner by reaction between o-phenylenediamines and appropriate 1,8-naphthalenedicarboxylic anhydrides using acidic alumina under microwave irradiation  

    Comparison between Performance of Stone Columns and RAPs from the Bearing Capacity and Settlement Reduction Viewpoints

    , M.Sc. Thesis Sharif University of Technology Golestani Dariani, Ali Akbar (Author) ; Pak, Ali (Supervisor)
    Abstract
    Out of several ground improvement techniques available, stone columns have been widely used. This technique has been successfully applied to increase the bearing capacity and to reduce the settlement for foundation of structures like liquid storage tanks, earthen embankments, raft foundations, etc., where a relatively large settlement is permissible. This technique has, generally, been proven successful in increasing the stiffness of weak soils, upgrading their safe bearing capacity, and reducing their total and differential settlements, as well as speeding up their consolidation process. The beneficial effects of stone column installation in weak deposits is manifested in the form of...