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Experimental Determination & Thermodynamic Modeling of Solubility of Gases in Ionic Liquids
,
M.Sc. Thesis
Sharif University of Technology
;
Ghotbi, Cyrus
(Supervisor)
;
Behzadi, Bahman
(Supervisor)
;
Jalili, Amir Hossein
(Supervisor)
;
Ahmadi, Amir Naser
(Co-Advisor)
Abstract
Ionic liquids (IL's) are found to be potentially suitable solvents for the chemical process industry, especially due to their negligible vapor pressure which can result in a major decrease of solvent loss and the environmental harm. One of the foreseeable industrial applications in the field of natural gas processing is the replacement of traditional organic solvents (usually alkanol amines) presently used for the absorption of H2S from sour gases, by suitable IL's. Ionic liquids have been proposed for the separation of gas mixtures. In particular, ionic liquids have been suggested for the removal of the acid gases, hydrogen sulfide, and carbon dioxide, from natural gases and refinery gases....
Biodegradation of heavy fuel oil by newly isolated strain enterobacter cloacae BBRC10061: Study of unstructured kinetic models and innovative equation
, Article Scientia Iranica ; Volume 20, Issue 6 , 2013 , Pages 1929-1938 ; 10263098 (ISSN) ; Mashreghi, M ; Yaghmaei, S ; Sharif University of Technology
Sharif University of Technology
2013
Abstract
Modeling process is very important and valuable to predict process outcome, especially bioprocesses which are intricate. Because of complex hydrocarbon compounds and oscillations happened in the medium of process, biodegradation of mazut has not already been investigated by mathematical models. In this study, an indigenous bacterium was isolated from oil contaminated soil to investigate biodegradation of mazut at different experimental conditions. Data resulted from mazut degradation, pH, and electrical potential in the medium were recorded. Some reported kinetic models and combinations were investigated to practically model the process. In addition, a new equation that can predict various...
Collective behavior of interacting locally synchronized oscillations in neuronal networks
, Article Communications in Nonlinear Science and Numerical Simulation ; Volume 17, Issue 10 , 2012 , Pages 3922-3933 ; 10075704 (ISSN) ; Sharif University of Technology
Elsevier
2012
Abstract
Local circuits in the cortex and hippocampus are endowed with resonant, oscillatory firing properties which underlie oscillations in various frequency ranges (e.g. gamma range) frequently observed in the local field potentials, and in electroencephalography. Synchronized oscillations are thought to play important roles in information binding in the brain. This paper addresses the collective behavior of interacting locally synchronized oscillations in realistic neural networks. A network of five neurons is proposed in order to produce locally synchronized oscillations. The neuron models are Hindmarsh-Rose type with electrical and/or chemical couplings. We construct large-scale models using...
Second virial coefficients of Exp-6 chains: A Monte Carlo simulation
, Article Chemical Physics ; Volume 397, Issue 1 , March , 2012 , Pages 26-33 ; 03010104 (ISSN) ; Ramazani Saadatabadi, A ; Khanpour, M ; Sharif University of Technology
2012
Abstract
The second virial coefficients of Exp-6 chains are calculated using the Monte Carlo method. The results are presented as the scaled second virial coefficient B 2/(m 2σ 3) for various chain lengths m and repulsive-wall steepness parameters α at different scaled temperatures T *. The scaled coefficient reduces and converges to a constant value as m → ∞. Interestingly, the scaled coefficient scales as B 2/(m 2σ 3) ∝ -α -1, where the dependence reduces for larger m. The gyration radius increases with α, and in good solvent regime, scales like a self-avoiding chain when m → ∞. The interaction energy between two chains depends on m, T *, and α. With increasing m, the interaction becomes less...
A novel method for production of foamy core@compact shell Ti6Al4V bone-like composite
, Article Journal of Alloys and Compounds ; Volume 656 , 2016 , Pages 416-422 ; 09258388 (ISSN) ; Sadrnezhad, S. K ; Sharif University of Technology
Elsevier Ltd
Abstract
This paper presents a novel method for fabrication of bone-like Ti6Al4V foamy core@compact shell composite for utilization as substitutive implant for cortical bone having porous core. Seven prototypes with core-diameters of 0, 6, 8, 10, 12, 14 and 16 mm surrounded by dense shells of respective thicknesses 8, 5, 4, 3, 2, 1 and 0 were produced by an innovative two-stage packing/compaction sintering method. Density, porosity, Young's modulus and compression strength of the prototypes depended on the core diameter. Mechanical strength and Young's modulus of 10@16 (10 mm core, 16 mm diameter prototypes) resembled that of the human ulna bone. Creation of foam at the center was achieved by...
Drop formation in cross-junction micro-channel using lattice Boltzmann method
, Article Thermal Science ; Volume 22, Issue 2 , 2018 , Pages 909-919 ; 03549836 (ISSN) ; Taeibi Rahni, M ; Mohammadzadeh, A ; Najafi, M ; Sharif University of Technology
Serbian Society of Heat Transfer Engineers
2018
Abstract
Drop formation in cross-junction micro-channels is numerically studied using the lattice Boltzmann method with pseudo-potential model. To verify the simulation, the results are compared to previous numerical and experimental data. Furthermore, the effects of capillary number, flow rate ratio, contact angle, and viscosity ratio on the flow patterns, drop length, and interval between drops are investigated and highlighted. The results show that the drop forming process has different regimes, namely, jetting, drop, and squeezing regimes. Also, it is shown that increasing in the flow rate ratio in the squeezing regime causes increment in drop length and decrement in drops interval distance. On...
The effect of steepness of soft-core square-well potential model on some fluid properties
, Article Molecular Physics ; Volume 106, Issue 1 , 2008 , Pages 103-112 ; 00268976 (ISSN) ; Parsafar, G. A ; Sharif University of Technology
2008
Abstract
The effect of repulsive steepness of the soft-core square well (SCSW) potential model on the second virial coefficient, critical behaviour (two- phase region and the position of critical point), and coordination number are investigated. The soft-core thermodynamic perturbation theory (TPT) presented by Weeks-Chandler-Anderson (WCA) recently developed by Ben-Amotz and Stell (BAS) has been used for the reference system, and the Barker-Henderson TPT for the perturbed system. The Barker-Henderson macroscopic compressibility approximation has been used for all order perturbation terms in which the second-order one is improved by assuming that the molecules in every two neighbouring shells are...
Calculation of equilibrium and transport properties using modified hard-core potential models
, Article Chemical Physics ; Volume 326, Issue 2-3 , 2006 , Pages 527-534 ; 03010104 (ISSN) ; Khanpour, M ; Mohammadi, A. A ; Sharif University of Technology
2006
Abstract
We present in this paper a new method of modifying hard-core potentials to correctly predict the equilibrium and non-equilibrium properties of real fluids at low densities (specifically when ρ ≤ B/C where ρ is density, and B and C are the second and third virial coefficients) only by one set of potential parameters. Because the molecular diameter becomes smaller when temperature increases, we introduced a new expression for the variation of molecular diameter with temperature that incorporates this effect. The temperature dependence of the diameter was used in both Sutherland (ST) and square-well (SW) potential models to modify the second virial coefficient. Then we have shown that the...
Stimulus presentation can enhance spiking irregularity across subcortical and cortical regions
, Article PLoS Computational Biology ; Volume 18, Issue 7 , 2022 ; 1553734X (ISSN) ; Fakharian, M. A ; Ghazizadeh, A ; Sharif University of Technology
Public Library of Science
2022
Abstract
Stimulus presentation is believed to quench neural response variability as measured by fano-factor (FF). However, the relative contributions of within-trial spike irregularity and trial-to-trial rate variability to FF fluctuations have remained elusive. Here, we introduce a principled approach for accurate estimation of spiking irregularity and rate variability in time for doubly stochastic point processes. Consistent with previous evidence, analysis showed stimulus-induced reduction in rate variability across multiple cortical and subcortical areas. However, unlike what was previously thought, spiking irregularity, was not constant in time but could be enhanced due to factors such as...