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Effect of concentration on hydrodynamic size of magnetite-based ferrofluid as a potential MRI contrast agent
, Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; 2013 ; 09277757 (ISSN) ; Gu, N ; Sharif University of Technology
2013
Abstract
In this work, ferrofluids containing dextran coated magnetite nanoparticles have been synthesized via co-precipitation method. FT-IR results verified presence of dextran molecules on the particles surface. TEM results showed that mean particle size is 7.23 nm, while mean hydrodynamic size determined via PCS technique varies between 39.8 and 125.8 nm depending on the ferrofluid concentration. The maximum hydrodynamic size was obtained in mid concentrations. To the best of our knowledge, effect of concentration on mean hydrodynamic size has not been systematically studied before. VSM results confirmed the superparamagnetic behavior of the synthesized nanoparticles with saturation magnetization...
CFD Simulation of hydrodynamic of a bubble column reactor operating in churn-turbulent regime and effect of gas inlet distribution on system characteristics
, Article International Journal of Chemical Reactor Engineering ; Volume 14, Issue 1 , 2016 , Pages 213-224 ; 15426580 (ISSN) ; Zarkesh, J ; Rashtchian, D ; Anvari, A ; Sharif University of Technology
Walter de Gruyter GmbH
Abstract
CFD simulation of cylindrical bubble column including air as dispersed phase and water as continuous phase operating in churn-turbulent flow regime with diameter of 0.49 m, height of 3.6 m and gas superficial velocity of 0.14 m/s have been conducted. All simulations have been carried out in a 2D axisymmetric, unsteady and Euler/Euler framework with the aid of commercial software FLUENT v. 14.5. Simulations were validated by our experimental results through residence time distribution (RTD) data. Effect of bubble size distribution at inlet on column hydrodynamic was investigated and results clearly showed that equilibrium bubble size distribution in most parts of column is independent of...
Ultrasonic-assisted synthesis of magnetite based MRI contrast agent using cysteine as the biocapping coating
, Article Materials Chemistry and Physics ; Volume 131, Issue 1-2 , 2011 , Pages 170-177 ; 02540584 (ISSN) ; Malek, M ; Hosseini, H. R. M ; Shokrgozar, M. A ; Oghabian, M. A ; Masoudi, A ; Gu, N ; Zhang, Y ; Sharif University of Technology
2011
Abstract
Magnetite nanoparticles (mean particle size ranging from 10 to 20 nm) were prepared by a biomoleculeassisted solution-phase approach under ultrasonic irradiation. Cysteine was used as the capping agent in the solution. The results show that cysteine could be an efficient biocapping agent in producing Fe3O4 nanoparticles. The crystal structure and magnetic properties of the nanoparticles were characterized by XRD and VSM techniques, respectively. FT-IR was used to investigate the presence of cysteine on the nanoparticles surface. The influence of pH value of the solution on the size distribution and hydrodynamic size of nanoparticles were studied by TEM and DLS methods, respectively. The MTT...