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    EMCCD photometry reveals two new variable stars in the crowded central region of the globular cluster NGC 6981

    , Article Astronomy and Astrophysics ; Volume 553 , May , 2013 ; 00046361 (ISSN) Skottfelt, J ; Bramich, D. M ; Figuera Jaimes, R ; Jørgensen, U. G ; Kains, N ; W Harpsøe, K. B ; Liebig, C ; Penny, M.T ; Alsubai, K. A ; Andersen, J. M ; Bozza, V ; Browne, P ; Calchi Novati, S ; Damerdji, Y ; Diehl, C ; Dominik, M ; Elyiv, A ; Giannini, E ; Hessman, F ; Hinse, T.C ; Hundertmark, M ; Juncher, D ; Kerins, E ; Korhonen, H ; Mancini, L ; Martin, R ; Rabus, M ; Rahvar, S ; Scarpetta, G ; Southworth, J ; Snodgrass, C ; Street, R. A ; Surdej, J ; Tregloan Reed, J ; Vilela, C ; Williams, A ; Sharif University of Technology
    Two previously unknown variable stars in the crowded central region of the globular cluster NGC 6981 are presented. The observations were made using the electron multiplying CCD (EMCCD) camera at the Danish 1.54 m Telescope at La Silla, Chile. The two variableswere not previously detected by conventional CCD imaging because of their proximity to a bright star. This discovery demonstrates that EMCCDs are a powerful tool for performing high-precision time-series photometry in crowded fields and near bright stars, especially when combined with difference image analysis  

    Multi objective distributed generation planning using a binary particle swarm optimization method

    , Article 2008 International Conference on Genetic and Evolutionary Methods, GEM 2008, Las Vegas, NV, 14 July 2008 through 17 July 2008 ; 2008 , Pages 140-146 ; 1601320698 (ISBN); 9781601320698 (ISBN) Soroudi, A ; Ehsan, M ; Sharif University of Technology
    With the introduction of restructuring concepts to traditional power systems, a great deal of attention is given to utilization of distributed generation. Integration of DG units has been known as an alternative for distribution network reinforcement and purchasing energy from transmission network. Considering these facts, in the planning procedure of DG, determination of optimal sizing and sitting is a very important issue. This work presents a comprehensive framework for integration of distributed generations into a distribution network, regarding various technical and economical issues such as reduction of active power losses, environmental pollutions, investment and running costs while... 

    Green element solution of one-dimensional counter-current spontaneous imbibition in water wet porous media

    , Article Journal of Petroleum Science and Engineering ; Volume 70, Issue 3-4 , 2010 , Pages 302-307 ; 09204105 (ISSN) Biniaz Delijani, E ; Pishvaie, M. R ; Sharif University of Technology
    A Green Element numerical formulation is used to solve the time-dependent nonlinear one-dimensional counter-current spontaneous imbibition diffusion equation in which water enters a water wet rock spontaneously while oil escapes by flowing in the opposite direction. The Green Element Method (GEM) is an element by element approach of the boundary element method. In this new method, by generating large sparse global matrices and yet taking advantage of properties of Green's function, solution of more complicated physical problem is achievable while at the same time much less computational effort is needed rather than boundary element method (BEM). By discretizing both the boundary and problem...