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Evaluation of Exerted Drag Force on Alkane Saturated Air Bubbles in Aqueous Solutions by Experimental Studies
, M.Sc. Thesis Sharif University of Technology ; Bastani, Dariush (Supervisor) ; Lotfi, Marzieh (Supervisor)
Abstract
Interfacial phenomena and properties of interphase surfaces in dynamic mode play an important role in industrial processes that include gas-liquid and liquid-liquid multiphase flows. As well as, interface knowledge leads to better understanding of natural and fundamental phenomena. The present study has been performed for understanding about dynamic behavior of interphase surfaces in the presence of nanoparticles and hexane vapor in gas-liquid dispersion systems. In this research, rising bubble method has been used as one of the most conventional techniques. Accordingly, aqueous solutions of nanosilica were prepared in concentrations of 50, 100, 200, 400 and 1200 ppm as continuous phase...
Estimating terminal velocity of rough cracks in the framework of discrete fractal fracture mechanics
, Article Engineering Fracture Mechanics ; Volume 77, Issue 10 , 2010 , Pages 1516-1526 ; 00137944 (ISSN) ; Khezrzadeh, H ; Sharif University of Technology
2010
Abstract
In this paper we first obtain the order of stress singularity for a dynamically propagating self-affine fractal crack. We then show that there is always an upper bound to roughness, i.e. a propagating fractal crack reaches a terminal roughness. We then study the phenomenon of reaching a terminal velocity. Assuming that propagation of a fractal crack is discrete, we predict its terminal velocity using an asymptotic energy balance argument. In particular, we show that the limiting crack speed is a material-dependent fraction of the corresponding Rayleigh wave speed
Investigation of the impact of synthesized hydrophobic magnetite nanoparticles on mass transfer and hydrodynamics of stagnant and stirred liquid–liquid extraction systems
, Article Chemical Engineering Research and Design ; Volume 147 , 2019 , Pages 305-318 ; 02638762 (ISSN) ; Azizi, Z ; Bastani, D ; Sharif University of Technology
Institution of Chemical Engineers
2019
Abstract
The impact of modified magnetite nanoparticles (MMNPs)on hydrodynamics and mass transfer in liquid–liquid extraction process was assessed using a ternary chemical system of toluene-acetic acid–water. The organic phase which contained toluene and acetic acid was dispersed through water, and the mass transfer of acetic acid between two phases was investigated. The hydrophobic modified magnetite nanoparticles (MMNPs)prepared through an optimized in-situ method were added to the dispersed phase at different concentrations (0.001−0.005 wt%). Two separate conditions were provided in the experiments, i.e. stagnant and stirred continuous phase. The latter case was provided by a rotor at two...