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On the size-dependent behavior of drop contact angle in wettability alteration of reservoir rocks to preferentially gas wetting using nanofluid
, Article Journal of Petroleum Science and Engineering ; Volume 178 , 2019 , Pages 1143-1154 ; 09204105 (ISSN) ; Ghazanfari, M. H ; Dehghan Monfared, A ; Sharif University of Technology
Elsevier B.V
2019
Abstract
Wettability alteration of rock surfaces toward gas wetting have been recognized as a practical approach for maximizing the production from the gas condensate reservoirs. Most of the reported work in this area applied the so called sessile drop contact angle measurement technique to examine the change in wetting state of a surface. However, the size-dependent wetting behavior of drop which could affect the exact determination of wettability and wettability changes was not well discussed in the previous studies. Therefore, in this work, the size dependency of contact angle for four different liquid-solid-gas systems; i.e., water-calcite-air, water-treated calcite-air (nanofluid treated...
Compare numerical modeling and improved understanding of dynamic sessile drop contact angle analysis in Liquid-Solid-Gas system
, Article Journal of Petroleum Science and Engineering ; Volume 184 , 2020 ; Ghazanfari, M. H ; Dehghan Monfared, A ; Sharif University of Technology
Elsevier B.V
2020
Abstract
Dynamic contact angle measurement; as a standard method for surface wettability analysis, is usually conducted through the analysis of sessile drops formed following the low rate injection of fluid from beneath through a drilled hole via an injection needle. However, understanding/characterizing the changes of drop contact angle from the point where the flat solid surface begins is not well discussed yet. Moreover, during the evaluation of size-dependent behavior of contact angle of millimeter-scale drops, the effect of the drilled hole is ignored. In this regard, in the current study, the experimental and thermodynamic characterizations of the sessile drop advancing contact angle...
Wettability alteration of oil-wet carbonate porous media using silica nanoparticles: Electrokinetic characterization
, Article Industrial and Engineering Chemistry Research ; Volume 58, Issue 40 , 2019 , Pages 18601-18612 ; 08885885 (ISSN) ; Ghazanfari, M. H ; Sharif University of Technology
American Chemical Society
2019
Abstract
Application of nanoparticles for wettability alteration offers a practical approach to resolve some surface-related problems encountered in the nowadays technological process. Examples are underground/subsurface engineering implications, including the enhanced oil recovery from the oil-wet carbonate reservoirs. However, the common wettability evaluating techniques such as contact angle and flotation cannot be representative of the dynamic phenomena occurring at the pore scale and hence are unable to give accurate information about the process. Therefore, in the present work, the electrokinetic evaluations are utilized to explore the wettability alteration of initially oil-wet carbonate rock...
Adsorption of silica nanoparticles onto calcite: Equilibrium, kinetic, thermodynamic and DLVO analysis
, Article Chemical Engineering Journal ; Volume 281 , December , 2015 , Pages 334-344 ; 13858947 (ISSN) ; Ghazanfari, M. H ; Jamialahmadi, M ; Helalizadeh, A ; Sharif University of Technology
Elsevier
2015
Abstract
Recently, application of silica nanoparticles (SNP) for enhancing oil recovery during water flooding has been much attended. However, understanding how rock and nanoparticles (NP) interacts through adsorption onto the carbonate reservoir rocks is not well discussed. In this work, adsorption behavior of SNP onto the calcite had been characterized, through kinetic, equilibrium, thermodynamics and electrokinetic studies as well as interaction energy analysis by DLVO theory. Also, field emission scanning electron microscopy (FESEM) was utilized to visualize the adsorption process. It had been found that kinetic behavior of SNP-calcite system followed the pseudo-second order model. Equilibrium...
Potential application of silica nanoparticles for wettability alteration of oil-wet calcite: A mechanistic study
, Article Energy and Fuels ; Volume 30, Issue 5 , 2016 , Pages 3947-3961 ; 08870624 (ISSN) ; Ghazanfari, M. H ; Jamialahmadi, M ; Helalizadeh, A ; Sharif University of Technology
American Chemical Society
2016
Abstract
Oil recovery from carbonate reservoirs can be enhanced by altering the wettability from oil-wet toward water-wet state. Recently, silica nanoparticle (SNP) suspensions are considered as an attractive wettability alteration agent in enhanced oil recovery applications. However, their performance along with the underlying mechanism for wettability alteration in carbonate rocks is not well discussed. In this work, the ability of SNP suspensions, in the presence/absence of salt, to alter the wettability of oil-wet calcite substrates to a water-wet condition was investigated. In the first step, to ensure that the properties of nanofluids have not been changed during the tests, stability analysis...
Wettability alteration modeling for oil-wet calcite/silica nanoparticle system using surface forces analysis: contribution of DLVO versus non-DLVO interactions
, Article Industrial and Engineering Chemistry Research ; Volume 57, Issue 43 , 2018 , Pages 14482-14492 ; 08885885 (ISSN) ; Ghazanfari, M. H ; Kazemeini, M ; Jamialahmadi, M ; Helalizadeh, A ; Sharif University of Technology
American Chemical Society
2018
Abstract
In this work, application of silica nanoparticles for wettability alteration of initially oil-wet calcite was investigated through analysis of surface forces and DLVO theory. Doing so, the wettability and zeta potential of calcite surfaces were measured through the sessile drop method and an in-house experimental setup, respectively. Primary evaluation indicated that incorporating DLVO terms in the Frumkin-Derjaguin model was not sufficient to describe the wettability in an oil-wet calcite/nanofluid system. Sensitivity analysis showed that calculating the double-layer interaction using constant potential-constant potential boundaries along with structural hydrophobic forces (non-DLVO...
Wettability alteration of calcite rock from gas- repellent to gas-wet using a fluorinated nanofluid: A surface analysis study
, Article Journal of Natural Gas Science and Engineering ; Volume 83 , 2020 ; Shafiei, Y ; Shayesteh, M ; Dehghan Monfared, A ; Ghazanfari, M. H ; Sharif University of Technology
Elsevier B.V
2020
Abstract
Wettability alteration analysis form gas-repellent to gas-wet with the aid of chemical agents has been subjected of numerous studies. However, fundamental understanding of the effect of surface tension of liquid on repellency strength, the change in the intermolecular forces due to the adsorption of nanoparticles onto the rock surfaces, and exposure of treated rock in brine are not well discussed in the available literature. In this study, X-ray diffraction, Atomic Force Microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were applied to characterize the treated and fresh samples. Dynamic and static contact angle measurements were then combined with six methods...
Role of exponential and power law formulations in contact stress
, Article Indian Journal of Science and Technology ; Vol. 7, issue. 1 , 2014 , pp. 7-13 ; ISSN: 09746846 ; Hassan, M ; Daneshmand, S ; Taheran, F ; Monfared, A ; Sharif University of Technology
2014
Abstract
Analyzing contact stress in rails and wheels are very important in mechanical and railway engineering. In this paper, new formulations of the contact stress are presented for two rolling bodies by exponential and power law forms semi-analytically. Innovative elastic wheel-rail contact models and FE Modeling are proposed. The present model assumes the collection of rail and wheel as elastic deformable bodies and needs numerical and novel analytical solutions. Results of this work are close to the Hertz Stress, previous published work and FEM results, in which good agreements are found among the results. So, we can rely on this method and their results. With this approach, suitable results...
Upper bounds for the 2-hued chromatic number of graphs in terms of the independence number
, Article Discrete Applied Mathematics ; Volume 160, Issue 15 , 2012 , Pages 2142-2146 ; 0166218X (ISSN) ; Ahadi, A ; Sharif University of Technology
Elsevier
2012
Abstract
A 2-hued coloring of a graph G is a coloring such that, for every vertex v∈V(G) of degree at least 2, the neighbors of v receive at least two colors. The smallest integer k such that G has a 2-hued coloring with k colors is called the 2-hued chromatic number of G, and is denoted by χ2(G). In this paper, we will show that, if G is a regular graph, then χ2(G)-χ(G)≤2log 2(α(G))+3, and, if G is a graph and δ(G)<2, then χ2(G)-χ(G)≤1+4 Δ2δ-1⌉(1+log 2Δ(G)2Δ(G)-δ(G)(α(G))), and in the general case, if G is a graph, then χ2(G)-χ(G)≤2+min α′(G),α(G)+ω(G)2
Novel mathematical approaches for analyzing time dependent creep deformations in reinforced metals
, Article Journal of Mechanical Science and Technology ; Volume 27, Issue 11 , 2013 , Pages 3277-3285 ; 1738494X (ISSN) ; Mondali, M ; Abedian, A ; Sharif University of Technology
2013
Abstract
The objective of this paper is to present some novel insights for solving a second stage creep problem in metal matrix composites. First, a new analytical approach is developed for obtaining some unknowns in second stage creep of short fiber composites under an applied axial load. The unknowns are the radial, circumferential, axial, shear and equivalent stresses, which are determined by approximation of creep constitutive equations and using proper assumed displacement rates. A nonlinear differential equation is solved employing suitable and correct approximate assumptions. Then, the difference of the stress components utilizing creep constitutive equations and assumed displacement rates is...
Steady state creep behavior of short fiber composites by mapping, logarithmic functions (MF) and dimensionless parameter (DP) techniques
, Article Archives of Civil and Mechanical Engineering ; Volume 12, Issue 4 , December , 2012 , Pages 455-463 ; 16449665 (ISSN) ; Mondali, M ; Abedian, A ; Sharif University of Technology
2012
Abstract
A new mathematical insight based on logarithmic, polynomial mapping functions (MF), and dimensionless parameter (DP) models is presented for determination of some unknowns in the steady state creep stage of short fiber composites subjected to axial loading. These unknowns are displacement rate in outer surface of the unit cell, shear and equivalent stresses at interface and outer surface of the unit cell, and average axial stress in fiber. Dimensionless parameter technique is presented for determination of displacement rate and equivalent stress in outer surface of the unit cell. However, the polynomial mapping function is presented for determination of average axial stress in fiber. Most...
Steady-state creep analysis of polymer matrix composites using complex variable method
, Article Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science ; Volume 227, Issue 10 , 2013 , Pages 2182-2194 ; 09544062 (ISSN) ; Mondali, M ; Abedian, A ; Sharif University of Technology
2013
Abstract
A new analytical formulation is presented to study the steady-state creep in short fiber composites using complex variable method. In this new approach, both the fiber and matrix creep at low stresses and temperatures. To analyze the crept fiber, a plane stress model was used. Important novelties of the present analytical method are determination of displacement rates with proper boundary conditions in the crept fibers and also using the complex variable method in creep analyzing. It is noteworthy that the method can be useful to study the creep behavior in polymeric matrix composites due to their high capability of creep. Moreover, another significant application of the present method is to...
Novel salep-based chelating hydrogel for heavy metal removal from aqueous solutions
, Article Polymers for Advanced Technologies ; Volume 27, Issue 8 , 2016 , Pages 999-1005 ; 10427147 (ISSN) ; Pourjavadi, A ; Monfared, A ; Khorasani, Z ; Sharif University of Technology
John Wiley and Sons Ltd
2016
Abstract
A novel optimized chelating hydrogel was synthesized via graft copolymerization of acrylamide and 2-hydroxyethyl methacrylate (as two-dentate chelating co-monomer) onto salep (a multicomponent polysaccharide obtained from dried tubers of certain natural terrestrial orchids) using N,N′-methylenebisacrylamide as a crosslinker and ammonium persulfate as an initiator. Reaction parameters (N,N′-methylenebisacrylamide and ammonium persulfate amounts as well as acrylamide/2-hydroxyethyl methacrylate weight ratio) affecting the water absorption of the chelating hydrogel were optimized using a systematic method to achieve a hydrogel with high swelling capacity as possible. Heavy metal ion adsorption...
Microstructural studies and wear assessments of Ti/TiC surface composite coatings on commercial pure Ti produced by titanium cored wires and TIG process
, Article Materials Chemistry and Physics ; Volume 137, Issue 3 , 2013 , Pages 959-966 ; 02540584 (ISSN) ; Kokabi, A. H ; Asgari, S ; Sharif University of Technology
2013
Abstract
Tungsten Inert Gas (TIG) process and titanium cored wires filled with micro size TiC particles were employed to produce surface composite coatings on commercial pure Ti substrate for wear resistance improvement. Wire drawing process was utilized to produce several cored wires from titanium strips and titanium carbide powders. Subsequently, these cored wires were melted and coated on commercial pure Ti using TIG process. This procedure was repeated at different current intensities and welding travel speeds. Composite coating tracks were found to be affected by TIG heat input. The microstructural studies using optical and scanning electron microscopy supported by X-ray diffraction showed that...
Theoretical and Experimental Investigation of Interaction between Nanoparticles and Carbonate Porous Media
, Ph.D. Dissertation Sharif University of Technology ; Ghazanfari, Mohammad Hosseini (Supervisor) ; Jamialahmadi, Mohammad (Supervisor) ; Helalizadeh, Abbas (Supervisor) ; Kazemeini, Mohammad ($item.subfieldsMap.e)
Abstract
In recent years, application of silica nanoparticles for wettability alteration of reservoir rocks as an effective approach in enhancing oil recovery from petroleum reservoirs is introduced. However, in this area, lack of fundamental studies to provide a clear understanding about the interaction between these nanoparticles and carbonate rocks (as the predominant reservoir rocks in the world and Iran), which is of particular importance, is sensed. Therefore, the main purpose of this dissertation is to present a mechanistic investigation about the interaction of silica nanoparticles (the most used nanoparticles) with carbonate rock from theoretical and experimental viewpoints. To better...
Adaptive nonlinear observer design using feedforward neural networks
, Article Scientia Iranica ; Volume 12, Issue 2 , 2005 , Pages 141-150 ; 10263098 (ISSN) ; Alasty, A ; Sharif University of Technology
Sharif University of Technology
2005
Abstract
This paper concerns the design of a neural state observer for nonlinear dynamic systems with noisy measurement channels and in the presence of small model errors. The proposed observer consists of three feedforward neural parts, two of which are MLP universal approximators, which are being trained off-line and the last one being a Linearly Parameterized Neural Network (LPNN), which is being updated on-line. The off-line trained parts are able to generate state estimations instantly and almost accurately, if there are not catastrophic errors in the mathematical model used. The contribution of the on-line adapting part is to compensate the remainder estimation error due to uncertain parameters...
Nanomechanical properties of functionally graded composite coatings: Electrodeposited nickel dispersions containing silicon micro- and nanoparticles
, Article Materials Chemistry and Physics ; Volume 121, Issue 3 , June , 2010 , Pages 497-505 ; 02540584 (ISSN) ; Dolati, A ; Ghorbani, M ; Monfared, A ; Stroeve, P ; Sharif University of Technology
2010
Abstract
Functionally graded composite coatings constitute a class of materials which are mostly used for mechanical and tribological applications. Among these materials, nickel metal deposits with incorporation of SiC particles have excellent mechanical properties due to nickel metal and good tribological properties due to the SiC particles. In this work, nickel coatings containing different sizes of SiC particles, nanoparticles and microparticles (10 nm to 5 μm), were electrodeposited from an additive-free sulfate bath containing nickel ions and SiC particles. The material properties of the coatings were compared to nickel coatings containing microparticles (5 μm). The effect of current density,...
Erratum: Nanomechanical properties of functionally graded composite coatings: Electrodeposited nickel dispersions containing silicon micro- and nanoparticles (Materials Chemistry and Physics (2010) 121 (497-505))
, Article Materials Chemistry and Physics ; Volume 123, Issue 2-3 , October , 2010 , Pages 829- ; 02540584 (ISSN) ; Dolati, A ; Ghorbani, M ; Monfared, A ; Stroeve, P ; Sharif University of Technology
2010
Studying the Mechanistic Behavior of Heavy Oil Displacement Using a Group of Alkalis and Surfactant Mixtures
, Article Chemical Engineering Communications ; Vol. 202, issue. 3 , May , 2015 , p. 366-374 ; ISSN: 00986445 ; Jadaly, A ; Masihi, M ; Ayatollahi, S ; Sharif University of Technology
2015
Abstract
In this study, a mixture-based sulfonate-based surfactant with a novel formula capable of functioning in real oil reservoir conditions was prepared and some microscopic parameters, like its compatibility state, emulsion behavior, interfacial tension, and temperature dependency in the presence of a heavy oil sample, and two of the most popular alkalis were analyzed; then the results were compared with those of a commercial sulfate-based surfactant. The designed surfactant provided an optimum three-phase region in relatively high salinity media; however, its optimum value decreased when adding any alkaline materials; this trend was reversed for the solutions made with the sulfate-based...
Studying the mechanistic behavior of heavy oil displacement using a group of alkalis and surfactant mixtures
, Article Chemical Engineering Communications ; Volume 202, Issue 3 , 2015 , Pages 366-374 ; 00986445 (ISSN) ; Jadaly, A ; Masihi, M ; Ayatollahi, S ; Sharif University of Technology
Taylor and Francis Ltd
2015
Abstract
In this study, a mixture-based sulfonate-based surfactant with a novel formula capable of functioning in real oil reservoir conditions was prepared and some microscopic parameters, like its compatibility state, emulsion behavior, interfacial tension, and temperature dependency in the presence of a heavy oil sample, and two of the most popular alkalis were analyzed; then the results were compared with those of a commercial sulfate-based surfactant. The designed surfactant provided an optimum three-phase region in relatively high salinity media; however, its optimum value decreased when adding any alkaline materials; this trend was reversed for the solutions made with the sulfate-based...