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    Gaussian theory for spatially distributed self-propelled particles

    , Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 94, Issue 6 , 2016 ; 15393755 (ISSN) Seyed Allaei, H ; Schimansky Geier, L ; Ejtehadi, M. R ; Sharif University of Technology
    American Physical Society  2016
    Abstract
    Obtaining a reduced description with particle and momentum flux densities outgoing from the microscopic equations of motion of the particles requires approximations. The usual method, we refer to as truncation method, is to zero Fourier modes of the orientation distribution starting from a given number. Here we propose another method to derive continuum equations for interacting self-propelled particles. The derivation is based on a Gaussian approximation (GA) of the distribution of the direction of particles. First, by means of simulation of the microscopic model, we justify that the distribution of individual directions fits well to a wrapped Gaussian distribution. Second, we numerically... 

    Effect of a standing baffle on the flow structure in a rectangular open channel

    , Article Journal of Hydraulic Research ; Volume 48, Issue 3 , Jun , 2010 , Pages 400-404 ; 00221686 (ISSN) Jamshidnia, H ; Takeda, Y ; Firoozabadi, B ; Sharif University of Technology
    2010
    Abstract
    The effect of an intermediate standing baffle on the flow structure in a rectangular open channel has been investigated by a three-dimensional acoustic Doppler velocimeter. Investigation of time-averaged velocity profiles at different streamwise positions reveals that the approach flow is fully developed upstream of the baffle. By analysing the space-averaged power spectra of streamwise velocity, a peak structure was observed in the upstream baffle region. Downstream of the baffle this peak structure has been alleviated by the baffle. The same analysis for the vertical component indicates the existence of a peak structure both up- and downstream of the baffle. Consequently, a baffle affects... 

    Effects of cognitive load on the amount and temporal structure of postural sway variability in stroke survivors

    , Article Experimental Brain Research ; Volume 236, Issue 1 , 2018 , Pages 285-296 ; 00144819 (ISSN) Mehdizadeh, H ; Khalaf, K ; Ghomashchi, H ; Taghizadeh, G ; Ebrahimi, I ; Taghavi Azar Sharabiani, P ; Mousavi, S. J ; Parnianpour, M ; Sharif University of Technology
    Springer Verlag  2018
    Abstract
    This study aimed to investigate the variability in postural sway patterns during quiet standing in stroke survivors. The postural sway was measured in 19 stroke survivors, as well as 19 healthy demographically matched participants, at 3 levels of postural difficulty (rigid surface with closed and open eyes, and foam surface with closed eyes), and 3 levels of cognitive difficulty (without a cognitive task, easy and difficult cognitive tasks). Both linear analyses (the amount of postural sway variability, including the standard deviation of the COP velocity in both the anteroposterior (AP) and mediolateral (ML) directions), as well as non-linear analyses [the temporal structure of the COP...