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    Neural network and neuro-fuzzy assessments for scour depth around bridge piers

    , Article Engineering Applications of Artificial Intelligence ; Volume 20, Issue 3 , 2007 , Pages 401-414 ; 09521976 (ISSN) Bateni, S. M ; Borghei, S. M ; Jeng, D. S ; Sharif University of Technology
    The mechanism of flow around a pier structure is so complicated that it is difficult to establish a general empirical model to provide accurate estimation for scour. Interestingly, each of the proposed empirical formula yields good results for a particular data set. Hence, in this study, alternative approaches, artificial neural networks (ANNs) and adaptive neuro-fuzzy inference system (ANFIS), are proposed to estimate the equilibrium and time-dependent scour depth with numerous reliable data base. Two ANN models, multi-layer perception using back-propagation algorithm (MLP/BP) and radial basis using orthogonal least-squares algorithm (RBF/OLS), were used. The equilibrium scour depth was... 

    Nonlinear dynamic analysis of SWNTs conveying fluid using nonlocal continuum theory

    , Article Structural Engineering and Mechanics ; Volume 66, Issue 5 , 10 June , 2018 , Pages 621-629 ; 12254568 (ISSN) Hosseini Kordkheili, S. A ; Mousavi, T ; Bahai, H ; Sharif University of Technology
    Techno Press  2018
    By employing the nonlocal continuum field theory of Eringen and Von Karman nonlinear strains, this paper presents an analytical model for linear and nonlinear dynamics analysis of single-walled carbon nanotubes (SWNTs) conveying fluid with different boundary conditions. In the linear analysis the natural frequencies and critical flow velocities of SWNTs are computed. However, in the nonlinear analysis the effect of nonlocal parameter on nonlinear dynamics of cantilevered SWNTs conveying fluid is investigated by using bifurcation diagram, phase plane and Poincare map. Numerical results confirm existence of chaos as well as a period-doubling transition to chaos. Copyright © 2018 Techno-Press,... 

    Relative and interactive effects of fluid's physicochemical characteristics on the incipient motion of a granular particle under laminar flow condition

    , Article Journal of Hydraulic Engineering ; Volume 144, Issue 5 , 2018 ; 07339429 (ISSN) Xiao, M ; Gholizadeh Vayghan, A ; Adams, B. T ; Rajabipour, F ; Sharif University of Technology
    American Society of Civil Engineers (ASCE)  2018
    This paper presents an experimental research for studying the relative and interactive effects of three physicochemical fluid characteristics (viscosity, pH, and ionic strength) on the incipient motion of a granular particle under laminar flow condition. Critical flow velocity for particle's incipient motion, an important factor for evaluating flow-induced soil erosion, was used to quantify the relative erosive capacity of the test fluids. Response surface methodology (RSM), a statistical design of experiments, was used to design and implement 20 test fluids with various levels of the three fluid characteristics. Incipient motion of a highly spherical glass bead positioned atop a specially...