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    Rheological and morphological properties of nanocomposites based on PA66/PA6/multi-walled carbon nanotube prepared by melt mixing

    , Article ICCM International Conferences on Composite Materials, 21 August 2011 through 26 August 2011, Jeju ; August , 2011 Hadizadeh, A. M ; Shojaei, A ; Bagheri, R ; Sharif University of Technology

    Detail study on improving micro/nano gas mixer performances in slip and transitional flow regimes

    , Article Sensors and Actuators, B: Chemical ; Volume 218 , October , 2015 , Pages 78-88 ; 09254005 (ISSN) Darbandi, M ; Sabouri, M ; Sharif University of Technology
    Elsevier  2015
    Abstract
    The mixer geometry has substantial effect on mixing performance of different micro/nanomixers. Despite past numerous studies dedicated to mixing of liquid flow streams, there are less efforts to investigate the geometry effects on gas mixing performances. In this work, we focus on gas-gas mixing through different micro/nanoscale mixers under slip and transitional flow regimes. We use the direct simulation Monte Carlo (DSMC) method to provide accurate and reliable results in such flow regimes. To extend our study, we implement different geometrical parameters in our consideration including the mixer size, the impact angle between two incoming gas streams, and the contraction height located in... 

    Analyzing mixing quality in a curved centrifugal micromixer through numerical simulation

    , Article Chemical Engineering and Processing: Process Intensification ; 2017 ; 02552701 (ISSN) Shamloo, A ; Vatankhah, P ; Akbari, A ; Sharif University of Technology
    Elsevier B.V 
    Abstract
    The Lab On a CD (LOCD), also known as Centrifugal Microfluidics, has evolved into a sophisticated platform for performing biomedical assays due to its marvelous miniaturization and accurate simulation of biological reactions. Among the numerous applications of the LOCD is fluid mixing. In this paper a centrifugal, serpentine micromixer is simulated and reformed toward better mixing performance. The micromixer was chosen to be curved as a curved design was found to be thrice as functional and compact as a rectilinear design, mixing-wise. The two angular velocity and opening radius parameters were originally hypothesized to affect mixing performance. Effect of angular velocity was studied over... 

    Analyzing mixing quality in a curved centrifugal micromixer through numerical simulation

    , Article Chemical Engineering and Processing: Process Intensification ; Volume 116 , 2017 , Pages 9-16 ; 02552701 (ISSN) Shamloo, A ; Vatankhah, P ; Akbari, A ; Sharif University of Technology
    Elsevier B.V  2017
    Abstract
    The Lab On a CD (LOCD), also known as Centrifugal Microfluidics, has evolved into a sophisticated platform for performing biomedical assays due to its marvelous miniaturization and accurate simulation of biological reactions. Among the numerous applications of the LOCD is fluid mixing. In this paper a centrifugal, serpentine micromixer is simulated and reformed toward better mixing performance. The micromixer was chosen to be curved as a curved design was found to be thrice as functional and compact as a rectilinear design, mixing-wise. The two angular velocity and opening radius parameters were originally hypothesized to affect mixing performance. Effect of angular velocity was studied over... 

    Reserve capacity of mixed urban road networks, network configuration and signal settings

    , Article Intelligent Transportation and Planning: Breakthroughs in Research and Practice ; February , 2018 , Pages 883-906 ; 9781522552116 (EISBN) Divsalar, M ; Hassanzadeh, R ; Mahdavi, I ; Mahdavi Amiri, N ; Sharif University of Technology
    IGI Global  2018
    Abstract
    The authors formulate the transportation mixed network design problem (MNDP) as a mixed-integer bi-level mathematical problem, based on the concept of reserve capacity. The upper level goal is to maximize the reserve capacity by signal settings at intersections, determine street direction and increase street capacities via addition of lanes. The lower level problem is a deterministic user equilibrium traffic assignment problem to minimize the user travel time. The model being non-convex, meta-heuristic methods are used to solve the problem. A hybridization of genetic algorithm with simulated annealing and a bee algorithm are proposed. Numerical examples are illustrated to verify the... 

    Computer simulations of sodium formate solution in a mixing tank

    , Article Communications in Nonlinear Science and Numerical Simulation ; Volume 13, Issue 2 , 2008 , Pages 380-399 ; 10075704 (ISSN) Mousavi, S. M ; Zamankhan, P ; Jafari, A ; Sharif University of Technology
    2008
    Abstract
    Traditionally, solid-liquid mixing has always been regarded as an empirical technology with many aspects of mixing, dispersing and contacting were related to power draw. One important application of solid-liquid mixing is the preparation of brine from sodium formate. This material has been widely used as a drilling and completion fluid in challenging environments such as the Barents Sea. In this paper, large-eddy simulations of a turbulent flow in a solid-liquid baffled cylindrical mixing vessel with large number of solid particles are performed to obtain insight into the fundamental aspects of a mixing tank. The impeller-induced flow at the blade tip radius is modeled by using the... 

    Comparative analysis of different static mixers performance by CFD technique: An innovative mixer

    , Article Chinese Journal of Chemical Engineering ; Volume 28, Issue 3 , 2020 , Pages 672-684 Haddadi, M. M ; Hosseini, S. H ; Rashtchian, D ; Olazar, M ; Sharif University of Technology
    Chemical Industry Press  2020
    Abstract
    The flow and mixing behavior of two miscible liquids has been studied in an innovative static mixer by using CFD, with Reynolds numbers ranging from 20 to 160. The performance of the new mixer is compared with those of Kenics, SMX, and Komax static mixers. The pressure drop ratio (Z-factor), coefficient of variation (CoV), and extensional efficiency (α) features have been used to evaluate power consumption, distributive mixing, and dispersive mixing performances, respectively, in all mixers. The model is firstly validated based on experimental data measured for the pressure drop ratio and the coefficient of variation. CFD results are consistent with measured data and those obtained by... 

    Mixing performance of T, Y, and oriented Y-micromixers with spatially arranged outlet channel: evaluation with villermaux/dushman test reaction

    , Article Microsystem Technologies ; 2016 , Pages 1-14 ; 09467076 (ISSN) Rahimi, M ; Azimi, N ; Parsamogadam, M. A ; Rahimi, A ; Masahy, M. M ; Sharif University of Technology
    Springer Verlag  2016
    Abstract
    This study aims to investigate the micromixing performance of three basic types of spatial shaped micromixers. New configurations of T, Y, and oriented Y-spatial mixers were designed with change in the angles of the confluence and the outlet channel to achieve the efficient micromixing. These micromixers offer advantages that are not attainable with the typical types of these mixers. Experimental tests were carried out in the laminar flow regime and the mixing efficiency was evaluated using Villermaux/Dushman test reaction. The geometries of the channels were cylindrical with the length of 30 mm and the diameter of 800 μm. The experimental results show that the angle of outlet channel has a... 

    Mixing performance of T, Y, and oriented Y-micromixers with spatially arranged outlet channel: evaluation with Villermaux/Dushman test reaction

    , Article Microsystem Technologies ; Volume 23, Issue 8 , 2017 , Pages 3117-3130 ; 09467076 (ISSN) Rahimi, M ; Azimi, N ; Parsamogadam, M. A ; Rahimi, A ; Masahy, M. M ; Sharif University of Technology
    Springer Verlag  2017
    Abstract
    This study aims to investigate the micromixing performance of three basic types of spatial shaped micromixers. New configurations of T, Y, and oriented Y-spatial mixers were designed with change in the angles of the confluence and the outlet channel to achieve the efficient micromixing. These micromixers offer advantages that are not attainable with the typical types of these mixers. Experimental tests were carried out in the laminar flow regime and the mixing efficiency was evaluated using Villermaux/Dushman test reaction. The geometries of the channels were cylindrical with the length of 30 mm and the diameter of 800 μm. The experimental results show that the angle of outlet channel has a... 

    A mixed integer linear programming based approach for unit commitment in smart grid environment

    , Article Journal of Engineering Research ; Vol. 2, issue. 3 , November , 2014 , p. 131-157 ; 23071877 Ghadiri Anari, R ; Rashidinejad, M ; Fotuhi-Firuzabad, M ; Sharif University of Technology
    Abstract
    The future of power systems known as smart grids is expected to involve an increasing level of intelligence and incorporation of new information and communication technologies in every aspect of the power grid. Demand response resources and gridable vehicle are two interesting programs which can be utilized in the smart grid environment. Demand response resources can be used as a demand side virtual power plant (resource) to enhance the security and reliability of utility and have the potential to offer substantial benefits in the form of improved economic efficiency in wholesale electricity markets. An economic model of incentive responsive loads is modelled based on price elasticity of... 

    Correlation of viscosity of aqueous solutions of alkanolamine mixtures based on the Eyring's theory and Wong-Sandler mixing rule

    , Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 32, Issue 2 , 2013 , Pages 9-17 ; 10219986 (ISSN) Ahmad Kelayeh, S ; Ghotbi, C ; Taghikhani, V ; Jalili, A ; Sharif University of Technology
    2013
    Abstract
    A viscosity model, based on Eyring's absolute rate theory combined with a cubic PR equation of state and Wong-Sandler mixing rule, has been proposed in order to correlate viscosities of aqueous solutions of alkanolamine mixtures at atmospheric pressure and different temperatures. In the proposed method, the energy and size parameters in studied Equation of State (EoS) have been obtained using the Wong - Sandler (WS) mixing rule combined with the NRTL and Wilson Gibbs equations. The NRTL and Wilson parameters for aqueous solutions of alkanolamine mixtures have been correlated using measured viscosity data at atmospheric pressure and different temperatures. The overall average deviation... 

    Approximated Cramér-Rao bound for estimating the mixing matrix in the two-sensor noisy Sparse Component Analysis (SCA)

    , Article Digital Signal Processing: A Review Journal ; Volume 23, Issue 3 , 2013 , Pages 771-779 ; 10512004 (ISSN) Zayyani, H ; Babaie Zadeh, M ; Sharif University of Technology
    2013
    Abstract
    In this paper, we address theoretical limitations in estimating the mixing matrix in noisy Sparse Component Analysis (SCA) in the two-sensor case. We obtain the Cramér-Rao Bound (CRB) error estimation of the mixing matrix based on the observation vector x=(x1,x2)T. Using the Bernoulli-Gaussian (BG) sparse distribution for sources, and some reasonable approximations, the Fisher Information Matrix (FIM) is approximated by a diagonal matrix. Then, the effect of off-diagonal terms in computing the CRB is investigated. Moreover, we compute an oracle CRB versus the blind uniform CRB and show that this is only 3 dB better than the blind uniform CRB. Finally, the CRB, the approximated CRB, the... 

    Mixing enhancement of two gases in a microchannel using DSMC

    , Article Applied Mechanics and Materials, Dubai ; Volume 307 , 2013 , Pages 166-169 ; 16609336 (ISSN) ; 9783037856598 (ISBN) Darbandi, M ; Lakzian, E ; Sharif University of Technology
    2013
    Abstract
    In high Knudsen number flow regimes microgas flow analysis may not be performed accurately using the classical CFD methods. Alternatively, the gas flow through micro-geometries can be investigated reliably using the direct simulation Monte Carlo (DSMC) method. Our concern in this paper is to use DSMC to study the mixing of two gases in entering simultaneously into a microchannel. The mixing process is assumed to be complete when the mass composition of each species deviates by no more than ±1% from its equilibrium composition. To enhance the mixing process, we focus on the effects of inlet-outlet pressure difference and the pressure ratios of the two incoming CO and N2 streams on the mixing... 

    Shearing and mixing effects on synthesis and properties of organoclay/polyester nanocomposites

    , Article Rheologica Acta ; Volume 51, Issue 11-12 , November , 2012 , Pages 1007-1019 ; 00354511 (ISSN) Rajabian, M ; Samadfam, M ; Naderi, G ; Beheshty, M. H ; Sharif University of Technology
    2012
    Abstract
    Mixing of solid nanoparticles in viscous fluids is a key stage in synthesis of nanocomposites and can affect their final properties. A multi-step preparatory mixing is developed to synthesize the nanocomposites of layered silicate in thermosetting polymers. This study aims to investigate the influences of mixing conditions and steps taken to process the thermosetting nanocomposites on the viscoelastic properties of suspensions. We also examine subsequent influences of mixing on the microstructure and dispersion state of cured hybrids of organically modified clays in a polyester resin. The nanocomposites were prepared in a sequential mixing process developed for the model nanocomposites of... 

    Gas transport behavior of DMDCS modified MCM-48/polysulfone mixed matrix membrane coated by PDMS

    , Article Korean Journal of Chemical Engineering ; Volume 28, Issue 10 , July , 2011 , Pages 2069-2075 ; 02561115 (ISSN) Jomekian, A ; Mansoori, S. A. A ; Monirimanesh, N ; Shafiee, A ; Sharif University of Technology
    2011
    Abstract
    Mesoporous MCM-48 silica was synthesized by templating method and the structure of particles was characterized by XRD, TEM and N 2 adsorption techniques. The surface modification of particles in order for introducing into PSF matrix was performed by dimethyldichlorosilane (DMDCS) silylation agent. SEM images of as-synthesized and modified MCM-48/PSF MMMs indicate that in the modified MCM-48 silica particles adhered well to the PSF matrix and that the synthesized MMMs were defect free. The incorporation of MCM-48 particles in to the PSF matrix and also surface coating of these MMMs by polydimethylsiloxane (PDMS) were performed. The quality of surface coating was investigated by SEM images and... 

    Biodegradation kinetics and interactions of styrene and ethylbenzene as single and dual substrates for a mixed bacterial culture

    , Article Journal of Environmental Health Science and Engineering ; 2015 ; 2052336X (ISSN) Hazrati, H ; Shayegan, J ; Seyedi, S. M ; Sharif University of Technology
    BioMed Central Ltd  2015
    Abstract
    This study examined biodegradation kinetics of styrene and ethylbenzene as representatives of alkenylbenzenes and mono-alkylbenzenes, respectively. The compounds were studied independently and as binary mixtures using a series of aerobic batch degradation experiments introduced by acclimatized mix culture. Initial concentration of styrene and ethylbenzene in the liquid phase vacillated from 0 to 220 mg/l. The Andrew model was applied for the biodegradation of individual substrates and the estimated constants of the equation for styrene and ethylbenzene were μmax = 0.1581, 0.2090 (1/h), KS =25.91, 37.77 (mg/L), KI =13.15, 62.62 (mg/L), respectively. The accomplished parameters from single... 

    Fabrication and characterization of a polysulfone-graphene oxide nanocomposite membrane for arsenate rejection from water

    , Article Journal of Environmental Health Science and Engineering ; Volume 13, Issue 1 , 2015 ; 2052336X (ISSN) Rezaee, R ; Nasseri, S ; Mahvi, A. H ; Nabizadeh, R ; Mousavi, S. A ; Rashidi, A ; Jafari, A ; Nazmara, S ; Sharif University of Technology
    BioMed Central Ltd  2015
    Abstract
    Background: Nowadays, study and application of modified membranes for water treatment have been considered significantly. The aim of this study was to prepare and characterize a polysulfone (PSF)/graphene oxide (GO) nanocomposite membrane and to evaluate for arsenate rejection from water. Materials and methods: The nanocomposite PSF/GO membrane was fabricated using wet phase inversion method. The effect of GO on the synthesized membrane morphology and hydrophilicity was studied by using FE-SEM, AFM, contact angle, zeta potential, porosity and pore size tests. The membrane performance was also evaluated in terms of pure water flux and arsenate rejection. Results: ATR-FTIR confirmed the... 

    An imperialist competitive algorithm in mixed-model assembly line sequencing problem to minimise unfinished works

    , Article International Journal of Systems Science: Operations and Logistics ; Volume 6, Issue 2 , 2019 , Pages 179-192 ; 23302674 (ISSN) Zandieh, M ; Moradi, H ; Sharif University of Technology
    Taylor and Francis  2019
    Abstract
    Mixed-model assembly lines (MMALs) are a type of production lines where a variety of product models similar to product characteristics are assembled in a just-in-time production system. Usually, MMAL consists of a number of stations linked by a conveyor belt and each station has a work zone limited by upstream and downstream boundaries. To avoid improper interference between operators in the adjacent stations and excess of machine moving range, operators are forced to complete their operations within their predetermined work zone. There is a set of criteria on which to judge sequences of product models in terms of the effective utilisation of these lines. In this paper, the sequence of... 

    The performance comparison of improved continuous mixed P-norm and other adaptive algorithms in sparse system identification

    , Article International Journal of Advanced Intelligence Paradigms ; 2020 , Pages 65-74 ; Volume 16, Issue 1 Akhbari, A ; Ghaffari, A ; Sharif University of Technology
    Inderscience Publishers  2020
    Abstract
    One of the essential usages of adaptive filters is in sparse system identification on which the performance of classic adaptive filters is not acceptable. There are several algorithms that designed especially for sparse systems; we call them sparsity aware algorithms. In this paper we studied the performance of two newly presented adaptive algorithms in which P-norm constraint is considered in defining cost function. The general title of these algorithms is continuous mixed P-norm (CMPN). The performances of these algorithms are considered for the first time in sparse system identification. Also the performance of l0 norm LMS algorithm is analysed and compared with our proposed algorithms.... 

    Optimal production-distribution planning in electromotor manufacturing industries: a case study

    , Article International Journal of Advanced Operations Management ; Volume 12, Issue 1 , 28 May , 2020 , Pages 1-27 ; Print ISSN: 1758-938X; Online ISSN: 1758-9398 Heydarabadi, H ; Doniavi, A ; Babazadeh, R ; Shahmohammadi Azar, H ; Sharif University of Technology
    Inderscience Publishers  2020
    Abstract
    Optimal production-distribution planning prevents capital accumulation, reduces costs, unemployment of machinery, and provides a good plan to satisfying customer needs. In this paper, a mixed-integer linear programming (MILP) model is developed to determine optimal production-distribution planning in electromotor manufacturing industries. The proposed model is a multi-product and multi-period one in which optimal amounts of production, inventory and distribution are determined in different periods. Also, the possibility of capacity expansion of facilities in different periods are modelled to optimally determine the capacity increase if necessary. To validate the proposed model, it is applied...