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    Controlled Nucleation and Growth of CDS Nanoparticles by Turbulent Dispersion and Statistical Processin of Light Scattering From Nanoparticles

    , Ph.D. Dissertation Sharif University of Technology SHayeganfar, Farzaneh (Author) ; Rahimitabar, Mohammad Reza (Supervisor) ; Taghavinia, Nima (Supervisor)
    In this thesis, We propose and test a method for controlling the size of nanoparticles, which plays a fundamental role in their electrical, optical, and mechanical properties. The method utilizes turbulent mixing, and is applicable to the fabrication of any type of nanoparticle that uses a solution environment in the preparation process. We show by well-controlled experiments on the CdS nanoparticles, which are semiconducting materials, that the average size < d > of the particles decreases with Reynolds number Re. To gain a deeper understanding of the phenomena reported here, we have carried out molecular dynamics simulations of the processes. In second investigation, We provide a simple... 

    A novel correlation approach for viscosity prediction of water based nanofluids of Al2O3, TiO2, SiO2 and CuO

    , Article Journal of the Taiwan Institute of Chemical Engineers ; Volume 58 , 2016 , Pages 19-27 ; 18761070 (ISSN) KalantariMeybodi, M ; Daryasafar, A ; MoradiKoochi, M ; Moghadasi, J ; BabaeiMeybodi, R ; KhorramGhahfarokhi, A ; Sharif University of Technology
    Taiwan Institute of Chemical Engineers  2016
    Nanofluids viscosity is one of the most important thermophysical properties in nanofluids usage especially in chemical and petroleum engineering applications. So it is highly desirable to predict the viscosity of nanofluids accurately. Experimental measurements are impossible in most situations and present models are not comprehensive and efficient especially for high temperature, high volume concentration and high viscosity values. In this study, a new correlation has been developed based on the comprehensive database of water based Al2O3, TiO2, SiO2 and CuO nanofluids viscosity data found in literature. The proposed correlation uses temperature, nanoparticle size, nanoparticle volumetric... 

    Synthesis and characterization of novel 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazatetracyclo dodecane based nanopolymer-bonded explosives by microemulsion

    , Article Journal of Molecular Liquids ; Volume 206 , June , 2015 , Pages 190-194 ; 01677322 (ISSN) Bayat, Y ; Soleyman, R ; Zarandi, M ; Sharif University of Technology
    Elsevier  2015
    2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazatetracyclo dodecane (CL-20)-based polymer/plastic bonded explosives are used in propellant formulation. It can be predicted that CL-20-based nano-polymer/plastic bonded explosives are able to have reduced composite sensitivity and superior mechanical strength. In the current study, we have prepared two kinds of CL-20-based nano-polymer/plastic bonded explosives with ethylene-vinyl acetate copolymer and glycidyl azide polymer via the microemulsion method. Several visual techniques such as SEM/AFM/TEM techniques have been utilized for complete characterization of CL-20-based... 

    Effect of nanoparticle behaviour on mud cake buildup for directional and horizontal wells: mathematical modelling and experimental study

    , Article Journal of Experimental Nanoscience ; Volume 11, Issue 12 , 2016 , Pages 975-999 ; 17458080 (ISSN) Sedaghatzadeh, M ; Ghazanfari, M. H ; Shahbazi, K ; Zargar, G ; Sharif University of Technology
    Taylor and Francis Ltd 
    The present study examined the effect of nanoparticle size and geometry on filter cake buildup during dynamic filtration using experimental and modeling approaches. A dynamic filtration setup was proposed and designed to test cross-flow circulation against a synthetic core at a constant differential pressure. The proposed mathematical model considers the critical deposition boundary of the porous media for particles along with drag, lift, friction, buoyancy, permeate, and electrostatic forces. The comprehensive model response allowed investigation of the aggregation and shape of nanoparticles at different cross-flow inclinations. The drag and lift force coefficients and moment of inertia of... 

    Sol–gel preparation and corrosion properties of Zn–SiO2 nanocomposite thin film

    , Article Journal of Sol-Gel Science and Technology ; Volume 79, Issue 1 , 2016 , Pages 133-143 ; 09280707 (ISSN) Razavizadeh, O ; Ghorbani, M ; Sharif University of Technology
    Springer New York LLC 
    In this study, a novel nanocomposite thin film of Zn–SiO2 is considered. The thin film is a viable alternative for higher abrasion-resistant coatings. DLS technique revealed that the nanoparticle size is to be below 10 nm, and FE-SEM showed particle size to be below 17 nm in the obtained coating. The coating was found to be highly adhesive with an amorphous structure and hardness value above 1000HV. Corrosion resistance studies using linear polarization technique revealed that this unique nanocomposite has a lower corrosion rate than hot-dip galvanized steel at higher positive potentials. A conclusive mechanism for corrosion and erosion improvement has been proposed. Graphical Abstract:... 

    New approaches in lowering the gas-phase synthesis temperature of TiO2 nanoparticles by H2O-assisted atmospheric pressure CVS process

    , Article Journal of Materials Research and Technology ; Volume 8, Issue 3 , 2019 , Pages 3024-3035 ; 22387854 (ISSN) Rahiminezhad Soltani, M ; Saberyan, K ; Simchi, A ; Gammer, C ; Sharif University of Technology
    Elsevier Editora Ltda  2019
    H2O-assisted atmospheric pressure chemical vapor synthesis is a modern economical process for the gas-phase synthesis of TiO2 nanoparticles. In the present work, the influence of synthesis temperatures (100-800 °C) on the phase structure, nanoparticle size, morphology, and agglomeration is investigated by transmission electron microscopy, selected area electron diffraction, X-ray diffraction, thermogravimetry, and differential thermal analysis. Down to 400 °C, crystalline TiO2 nanoparticles are synthesized and at 200 °C amorphous nanoparticles are formed. Therefore, a decrease in minimum synthesis temperature by more than 500 °C is achieved. In addition, the paper investigates the hypothesis... 

    Synthesis and cytotoxicity assessment of superparamagnetic iron-gold core-shell nanoparticles coated with polyglycerol

    , Article Journal of Colloid and Interface Science ; Volume 345, Issue 1 , 2010 , Pages 64-71 ; 00219797 (ISSN) Jafari, T ; Simchi, A ; Khakpash, N ; Sharif University of Technology
    Core-shell iron-gold (Fe@Au) nanoparticles were synthesized by a facile reverse micelle procedure and the effect of water to surfactant molar ratio (w) on the size, size distribution and magnetic properties of the nanoparticles was studied. MTT assay was utilized to evaluate the cell toxicity of the nanoparticles. To functionalize the particles for MRI imaging and targeted drug delivery, the particles were coated by polyglycerol through capping with thiol followed by polymerization of glycidol. The characteristics of the particles were examined by X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometere (VSM), UV-visible spectroscopy, and Fourier...