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    Modularity of Semi-stable Elliptic Curves

    , M.Sc. Thesis Sharif University of Technology Mahkam, Roohallah (Author) ; Jafari, Amir (Supervisor)
    Abstract
    Let E be a semi-stable elliptic curve over Q with conductor N and L(E,s) as its L-function. We say that E is modular if there exists an eigenform of weight 2 and level N over X_0(N) such that L(E,s) equals the L-function of f or L(E,s)=L(f,s). Wilse's method to prove this was by proving that the Galois representations induced by E and f are equivalent. First we will discuss that equivalency of those representations is equivalent to equality of L-functions and after that we will use deformation theory for Galois representations to overlook the main ideas of the proof of the modularity theorem. Wiles using the idea of deformation of Galois representaions proved that under proper conditions... 

    Iranian Professional Football League’s Scheduling

    , M.Sc. Thesis Sharif University of Technology Madadi, Mahdi (Author) ; Kianfar, Ferydoon (Supervisor)
    Abstract
    Finding a proper and fair schedule for sport competitions has been an important issue, especially these days which professional sports has became a large scale business and profitability of sport competitions depends on the quality of the schedule.
    Hence in the last three decades sport scheduling has been considered by computer science and operation research scientists.
    Professional soccer league consists of many teams which compete in one round or double round robin tournament every year. In round robin tournaments each team has two matches, one at their own place and the other one at the competitors place. The main issues of the sport scheduling are the round and the host of... 

    Investigation of Plasmonic Excitation in Carbonic Nanostructures Within Near-IR

    , M.Sc. Thesis Sharif University of Technology Madadi, Mahkam (Author) ; Jamshidi, Zahra (Supervisor)
    Abstract
    To date, the plasmonic properties of many metallic and semi-conducting materials have been investigated and used in various industries. One of the plasmonic material categories that have always been considered is polycyclic aromatic hydrocarbon or PAH, whose plasmonic resonance energy depends on the charge state of the molecule. In this regard, it is easy to change the plasmonic resonance energy via changing the induced charge, which is a unique feature of the mentioned materials. In addition, plasmonic structures with excitations in the infrared region are able to enhance the vibration intensity of absorbed molecules by increasing the electric field around themselves. Therefore, they have... 

    Vector space generated by the multiplicative commutators of a division ring

    , Article Journal of Algebra and its Applications ; Volume 12, Issue 8 , December , 2013 ; 02194988 (ISSN) Aghabali, M ; Akbari, S ; Ariannejad, M ; Madadi, A ; Sharif University of Technology
    2013
    Abstract
    Let D be a division ring with center F. An element of the form xyx -1y-1 ∈ D is called a multiplicative commutator. Let T(D) be the vector space over F generated by all multiplicative commutators in D. In this paper it is shown that if D is algebraic over F and Char(D) = 0, then D = T(D). We conjecture that it is true in general. Among other results it is shown that in characteristic zero if T(D) is algebraic over F, then D is algebraic over F  

    Experimental study and surface complexation modeling of non-monotonic wettability behavior due to change in brine salinity/composition: Insight into anhydrite impurity in carbonates

    , Article Journal of Molecular Liquids ; Volume 365 , 2022 ; 01677322 (ISSN) Madadi Mogharrab, J ; Ayatollahi, S ; Pishvaie, M. R ; Sharif University of Technology
    Elsevier B.V  2022
    Abstract
    Wettability alteration as the main mechanism of improved oil recovery in carbonates during low salinity/engineered water flooding (LS/EWF) is a complex phenomenon due to high heterogeneity of rock. During LS/EWF, wettability changes when electrochemical interactions at carbonate-brine interface happen. Anhydrite impurity in carbonates is one of the most important parameters affecting the electrochemical interactions at the rock-brine interface and the wettability alteration process. Therefore, the success of LS/EWF in carbonate reservoirs lies in perceiving the role of impurities such as anhydrite, from a geochemical and dissolution point of view. Modified flotation tests (MFT) were... 

    Performance predicting modeling of axial-flow compressor at design and off-design conditions

    , Article Proceedings of the ASME Turbo Expo, 9 June 2008 through 13 June 2008, Berlin ; Volume 6, Issue PART A , 2008 , Pages 317-324 ; 9780791843161 (ISBN) Madadi, A ; Hajilouy Benisi, A ; International Gas Turbine Institute ; Sharif University of Technology
    2008
    Abstract
    Axial flow compressor is one of the most important parts of gas turbine units. Therefore, its design and performance prediction are very important. One-dimensional modeling is a simple, fast and accurate method for performance prediction of any type of compressors with different geometries. In this approach, inlet flow conditions and compressor geometry are known and by considering various compressor losses, velocity triangles at rotor, and stator inlets and outlets are determined, and then compressor performance characteristics are predicted. Numerous models have been developed theoretically and experimentally for estimating various types of compressor losses. In present work, performance... 

    Optical analog of Matthiessen's rule in a one-dimensional model for diffusive light transport in foams

    , Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 82, Issue 4 , 2010 ; 15393755 (ISSN) Miri, M ; Kheradsoud, S ; Madadi, E ; Mokhtari, Z ; Hassani, H ; Sharif University of Technology
    2010
    Abstract
    We study photon diffusion in a one-dimensional model foam composed of thin films and Plateau borders. Each thin film or Plateau border is characterized by its own intensity transmittance. We relate | Foam, the transport-mean-free path of photons diffusing in the foam, to the foam microstructure. Denoting by l Film (l PB) the transport-mean-free path of photons in a medium composed only of thin films (Plateau borders), we find 1/ l Foam = φF / l Film + φP / l PB. Here φF and φP =1- φF are the fraction of films and Plateau borders, respectively  

    Analysis of mechanical and thermal properties of carbon and silicon nanomaterials using a coarse-grained molecular dynamics method

    , Article International Journal of Mechanical Sciences ; Volume 187 , December , 2020 Mohammadi, K ; Ali Madadi, A ; Bajalan, Z ; Nejat Pishkenari, H ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    The main concern in Molecular Dynamics (MD) simulations is the computational cost, and coarse-graining methods accelerate simulations by reducing the degrees of freedom in the system. Yet, the utilization of these methods should be carefully followed. In this paper, we presented an energy-based coarse-graining method for Tersoff and Stillinger-Weber potential functions. The presented coarse-graining method is based on the domain mapping and modification of potential function. The focus of this paper is on Carbon and Silicon materials; however, this method can be applied to model other materials for which Tersoff and Stillinger-Weber potentials are defined. This method has been validated by... 

    Coarse Grained-Atomistic Concurrent Multi-Scale Modeling for Numerical Simulation of Mechanical Behavior of Heterogeneous Materials in Nano-cale

    , M.Sc. Thesis Sharif University of Technology Ali Madadi Ahmadabadi, Ashkan (Author) ; Khoei, Amir Reza (Supervisor)
    Abstract
    In this thesis, a method has been exploited to couple the atomistic domain with the coarse-grained domain. Since molecular dynamics has a high computational cost when a large number of atoms exist, coarse-grained molecular dynamics was used in which a number of atoms are assumed as a bigger bid and interatomic potential is modified for bids so that the material’s mechanical properties remain constant. This method not only reduces the computational cost of calculating forces in molecular dynamics simulation but also, the time step used in Coarse-Grained Methods can be more than atomistic simulations as the frequency of occurring phenomena in CG scale is less than atomistic scale.The advantage... 

    Tube length-assisted optimized aerosol trapping

    , Article Optics Communications ; Vol. 329, issue , 2014 , pp. 196-199 ; ISSN: 00304018 Taheri, S. M. R ; Sadeghi, M ; Madadi, E ; S. Reihani, S. N ; Sharif University of Technology
    2014
    Abstract
    Trapping a single aerosol using optical tweezers could be of great importance for environmental sciences. Though a single nanoparticle as small as 10 nm is successfully trapped in aqueous media using optical tweezers, due to spherical aberration only large clusters of nanoparticles were stably trapped in air. In this paper we provide our theoretical and experimental results on optimized trapping of aerosols as small as 400 nm in radius by the introduction of an extra spherical aberration source in order to minimize the total spherical aberration of the system. Our method allows for trapping of high refractive index particles such as polystyrene beads in air. It also provides considerably... 

    Smart Water Optimal Injection Policy in Fractured Carbonate Reservoirs, Using Laboratory Data

    , M.Sc. Thesis Sharif University of Technology Madadi Mogharrab, Javad (Author) ; Ayatollahi, Shahaboddin (Supervisor) ; Pishvaie, Mahmood Reza (Supervisor)
    Abstract
    Wettability alteration is the main mechanism for enhancing oil recovery in carbonate reservoirs during low salinity or engineered water flooding (LS/EWF), though it is a complex process due to the high heterogeneity of rock. During LS/EWF, wettability alteration occurs as a result of electrochemical interactions at the interface between carbonate rock and brine. One of the most critical factors affecting these interactions, and the wettability alteration process, is the presence of anhydrite impurities in the carbonate rock. Therefore, the success of LS/EWF in carbonate reservoirs lies on understanding the role of impurities like anhydrite from both geochemical and dissolution perspectives....