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    Adsorption dynamics of surface-modified silica nanoparticles at solid-liquid interfaces

    , Article Langmuir ; Volume 38, Issue 41 , 2022 , Pages 12421-12431 ; 07437463 (ISSN) Khazaei, M. A ; Bastani, D ; Mohammadi, A ; Kordzadeh, A ; Sharif University of Technology
    American Chemical Society  2022
    Abstract
    Understanding the adsorption dynamics of nanoparticles at solid-liquid interfaces is of paramount importance to engineer nanoparticles for a variety of applications. The nanoparticle surface chemistry is significant for controlling the adsorption dynamics. This study aimed to experimentally examine the adsorption of surface-modified round-shaped silica nanoparticles (with an average diameter of 12 nm), grafted with hydrophobic (propyl chains) and/or hydrophilic (polyethylene glycol chains) agents, at an aqueous solution-silica interface with spherical soda-lime glass beads (diameter of 3 mm) being used as adsorbents. While no measurable adsorption was observed for solely hydrophobic or... 

    Effects of heat treatment on the corrosion behavior and mechanical properties of biodegradable Mg alloys

    , Article Journal of Magnesium and Alloys ; Volume 10, Issue 7 , 2022 , Pages 1737-1785 ; 22139567 (ISSN) Mohammadi Zerankeshi, M ; Alizadeh, R ; Gerashi, E ; Asadollahi, M ; Langdon, T. G ; Sharif University of Technology
    National Engg. Reaserch Center for Magnesium Alloys  2022
    Abstract
    Biodegradable magnesium (Mg) alloys exhibit great potential for use as temporary structures in tissue engineering applications. Such degradable implants require no secondary surgery for their removal. In addition, their comparable mechanical properties with the human bone, together with excellent biocompatibility, make them a suitable candidate for fracture treatments. Nevertheless, some challenges remain. Fast degradation of the Mg-based alloys in physiological environments leads to a loss of the mechanical support that is needed for complete tissue healing and also to the accumulation of hydrogen gas bubbles at the interface of the implant and tissue. Among different methods used to... 

    Mechanical properties and γ/γ' interfacial misfit network evolution: A study towards the creep behavior of Ni-based single crystal superalloys

    , Article Mechanics of Materials ; Volume 171 , 2022 ; 01676636 (ISSN) Khoei, A. R ; Youzi, M ; Tolooei Eshlaghi, G ; Sharif University of Technology
    Elsevier B.V  2022
    Abstract
    The aim of this study is to investigate the role of the temperature, stress, and rhenium (Re) on the γ/γ' interfacial misfit dislocation network and mechanical response of Ni-based single crystal superalloys. After aging at elevated temperatures, mismatch between the two phases results in an interfacial dislocation network to relieve the coherency stress. Molecular dynamics (MD) simulations have been performed to study the properties of the (100), (110), and (111) phase interface crystallographic directions. Increasing temperature disperses the atomic potential energy at the interface diminishing the strength and stability of the networks. In the case of loading, when a constant strain rate... 

    Selective fabrication of robust and multifunctional super nonwetting surfaces by diverse modifications of zirconia-ceria nanocomposites

    , Article Langmuir ; Volume 38, Issue 30 , 2022 , Pages 9195-9209 ; 07437463 (ISSN) Esmaeilzadeh, P ; Zandi, A ; Ghazanfari, M. H ; Khezrnejad, A ; Fatemi, M ; Molaei Dehkordi, A ; Sharif University of Technology
    American Chemical Society  2022
    Abstract
    The creation of surfaces with various super nonwetting properties is an ongoing challenge. We report diverse modifications of novel synthesized zirconia-ceria nanocomposites by different low surface energy agents to fabricate nanofluids capable of regulating surface wettability of mineral substrates to achieve selective superhydrophobic, superoleophobic-superhydrophilic, and superamphiphobic conditions. Surfaces treated with these nanofluids offer self-cleaning properties and effortless rolling-off behavior with sliding angles ≤7° for several liquids with surface tensions between 26 and 72.1 mN/m. The superamphiphobic nanofluid coating imparts nonstick properties to a solid surface whereby... 

    The effect of brine salinity and oil components on dynamic IFT behavior of oil-brine during low salinity water flooding: Diffusion coefficient, EDL establishment time, and IFT reduction rate

    , Article Journal of Petroleum Science and Engineering ; Volume 196 , 2021 ; 09204105 (ISSN) Farhadi, H ; Ayatollahi, S ; Fatemi, M ; Sharif University of Technology
    Elsevier B.V  2021
    Abstract
    Dynamic behavior of fluid-fluid interactions can potentially affect the performance of any enhanced oil recovery (EOR) process including low salinity water flooding. In this work, dynamic interfacial tension (IFT) of crude-oil/brine system is measured in a wide range of salinity of sea water (SW), from 50-time diluted sea water (SW50D) to 2-time concentrated sea water (SW2C). Contrary to the most of published IFT trends in the literature, for the system under investigation here, as the brine salinity increases the crude-oil/brine IFT reduces, which cannot be explained using the existing theories. The lack of a physical model to explain the observed phenomena was the motivation to develop a... 

    Solidification enhancement in triplex thermal energy storage system via triplets fins configuration and hybrid nanoparticles

    , Article Journal of Energy Storage ; Volume 34 , 2021 ; 2352152X (ISSN) Hosseinzadeh, K ; Montazer, E ; Shafii, M. B ; Ganji, A. R. D ; Sharif University of Technology
    Elsevier Ltd  2021
    Abstract
    Latent thermal energy storage dependent on Phase Change Materials (PCMs) proposes a possible answer for modifying the availability of alternating energy from renewable sources such as wind and solar. They can possibly store large amounts of energy in moderately tiny dimensions as well as through almost isothermal procedures. Notwithstanding, low thermal conductivity values is a significant disadvantage of the present PCMs which critically restrict their energy storage usage. Likewise, this unacceptably decreases the solidification/melting rates, hence causing the system response time to be excessively lengthy. The present examination accomplished a better PCM solidification rate with a... 

    Atomistic simulation of creep deformation mechanisms in nickel-based single crystal superalloys

    , Article Materials Science and Engineering A ; Volume 809 , 2021 ; 09215093 (ISSN) Khoei, A. R ; Tolooei Eshlaghi, G ; Shahoveisi, S ; Sharif University of Technology
    Elsevier Ltd  2021
    Abstract
    In this paper, the creep deformation mechanisms are investigated in nickel-based single crystal superalloys. Two-dimensional molecular dynamics (MD) simulations are conducted to model various temperatures, stress conditions, and phase interface crystal orientations. Ni-based single-crystal superalloys are of great importance in the aircraft industry due to their excellent high temperature creep resistance. This characteristic mainly originates from two features considered in their structure; firstly, their two-phase micro-structure comprising gamma γ and gamma prime γ′, and secondly the nature of this superalloy itself, which is a single-crystal. MD is a powerful tool to gain insight into... 

    Structural and dynamical fingerprints of the anomalous dielectric properties of water under confinement

    , Article Physical Review Materials ; Volume 5, Issue 2 , 2021 ; 24759953 (ISSN) Ahmadabadi, I ; Esfandiar, A ; Hassanali, A ; Ejtehadi, M. R ; Sharif University of Technology
    American Physical Society  2021
    Abstract
    There is a long-standing question about the molecular configuration of interfacial water molecules in the proximity of solid surfaces, particularly carbon atoms, which plays a crucial role in electrochemistry and biology. In this study, the dielectric, structural, and dynamical properties of confined water placed between two parallel graphene walls at different interdistances from the angstrom scale to a few tens of nanometer have been investigated using molecular dynamics. For the dielectric properties of water, we show that the dielectric constant of the perpendicular component of water drastically decreases under sub-2-nm spatial confinement. The dielectric constant data obtained through... 

    Structural and dynamical fingerprints of the anomalous dielectric properties of water under confinement

    , Article Physical Review Materials ; Volume 5, Issue 2 , 2021 ; 24759953 (ISSN) Ahmadabadi, I ; Esfandiar, A ; Hassanali, A ; Ejtehadi, M. R ; Sharif University of Technology
    American Physical Society  2021
    Abstract
    There is a long-standing question about the molecular configuration of interfacial water molecules in the proximity of solid surfaces, particularly carbon atoms, which plays a crucial role in electrochemistry and biology. In this study, the dielectric, structural, and dynamical properties of confined water placed between two parallel graphene walls at different interdistances from the angstrom scale to a few tens of nanometer have been investigated using molecular dynamics. For the dielectric properties of water, we show that the dielectric constant of the perpendicular component of water drastically decreases under sub-2-nm spatial confinement. The dielectric constant data obtained through... 

    Investigation of iron ore particle size and shape on green pellet quality

    , Article Canadian Metallurgical Quarterly ; Volume 59, Issue 2 , 2020 , Pages 242-250 Abazarpoor, A ; Halali, M ; Hejazi, R ; Saghaeian, M ; Sheikh Zadeh, V ; Sharif University of Technology
    Taylor and Francis Ltd  2020
    Abstract
    Particle size and shape of iron ore concentrate are effective parameters in the production of quality green pellets. In this research, the effect of particle morphology on green pellet quality was studied. It was concluded that pellet quality improved with increasing specific surface area. Drop number and green compression strength of pellets ground by HPGR were found to be superior over those ground in the ball mill. The chief reasons were related to particle shape and the fraction of fine particles. Smaller particle size results in a higher order of bonding between particles and therefore the formation of a stronger system. Also, the rougher and less circular shape of particles resulted in... 

    Efficient CO oxidation over palladium supported on various MOFs: Synthesis, amorphization, and space velocity of hydrogen stream

    , Article International Journal of Hydrogen Energy ; Volume 45, Issue 41 , 2020 , Pages 21450-21463 Abbasi, F ; Karimi Sabet, J ; Ghotbi, C ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    Amine-functionalized MIL-101(Cr) has been synthesized by hydrothermal (MNH2) and post-synthetic modification (MNH2-p) approaches. Pd/MNH2 and Pd/MNH2-p have been tested in CO oxidation reaction as a gas phase reaction to clarify the difference between two synthesis approaches. Their performance has also been compared with that of Pd supported on MIL as a common MOF and CuBTC as a commercial one. The results show the significant difference between Pd/MNH2-p and Pd/MNH2, where CO conversion of 100% was not observed for Pd/MNH2-p, whereas Pd/MNH2 outperformed the others and exhibited the high reaction rate thanks to the active sites created by amorphization during the reduction process because... 

    Optimization of microgrooves for water–solid drag reduction using genetic algorithm

    , Article Journal of Ocean Engineering and Marine Energy ; Volume 6, Issue 3 , 2020 , Pages 221-242 Abdollahzadeh, M. J ; Moosavi, A ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2020
    Abstract
    The friction on the water–solid interfaces continues to be the most important factor for the energy loss in many marine and submarine applications. Therefore, different techniques have been developed and are available to reduce friction and, as a result, the overall cost. In the past decades, the use of structured surfaces has been given considerable attention because of their specific characteristics such as their abilities in pressure drop reduction. However, an appropriate optimization method is required to find the best surface structure. In the present study, we consider a microgrooved substrate and examine the performance of three shapes including rectangular, elliptical, and... 

    A note on the synergistic effect of surfactants and nanoparticles on rising bubble hydrodynamics

    , Article Chemical Engineering and Processing - Process Intensification ; Volume 155 , 2020 Fayzi, P ; Bastani, D ; Lotfi, M ; Sharif University of Technology
    Elsevier B.V  2020
    Abstract
    Various mixtures of surfactants and nanosilica particles were investigated to assess their influence on rising bubble hydrodynamics. For this purpose, local velocities of rising bubbles were measured experimentally. Also, the effects of concentration of three types of surface-modified silica nanoparticles on density, viscosity, and surface tension of surfactant solutions were determined. Experimental results revealed that the simultaneous presence of nanoparticles and surfactant molecules led to the decrease of local velocities of rising bubbles. The presence of nanoparticles in surfactant solutions leads to a more reduction of bubble local velocity. This could be caused by the formation of... 

    Modeling of reactive acid transport in fractured porous media with the Extended–FEM based on Darcy-Brinkman-Forchheimer framework

    , Article Computers and Geotechnics ; Volume 128 , December , 2020 Khoei, A. R ; Salehi Sichani, A ; Hosseini, N ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    In this paper, a fully coupled numerical model is developed based on the X-FEM technique to simulate the reactive acid transport in fractured porous media. The porous medium consists of the solid and fluid phases, in which the fluid phase includes water and acid components, and chemical reactions can be occurred between acid component and solid phase at the solid–fluid interfaces. The governing equations include the mass and momentum conservation laws for fluid phase, and the advective–diffusive transport of acid component that must be solved to obtain the primary unknowns, including the pore fluid pressure, acid concentration, and fluid velocity vector. Applying the... 

    A model based on the equality of chemical potentials for describing the liquid-liquid interfaces of water-hydrocarbons up to high pressures

    , Article Journal of Molecular Liquids ; Volume 317 , November , 2020 Khosharay, S ; Feyzi, P ; Tourang, S ; Tajfar, F ; Sharif University of Technology
    Elsevier B. V  2020
    Abstract
    A reliable model was used to describe the interfacial tension, composition, and density of the liquid-liquid interfaces of water-hydrocarbons. The parachor model was combined with the equality of the chemical potential of components at the interface and the bulk liquid. The fugacity coefficient was used for computing chemical potentials. To compute the fugacity coefficients of the components, various types of equations of state (The Valderrama Patel-Teja, cubic plus association, and the simplified Perturbed-Chain Statistical Association Fluid Theory) were utilized. These models were applied to the temperature and the pressure range of (285.65–423) K and (1–3000) bar, respectively. The... 

    A comprehensive review on recent advances in superhydrophobic surfaces and their applications for drag reduction

    , Article Progress in Organic Coatings ; Volume 140 , March , 2020 Liravi, M ; Pakzad, H ; Moosavi, A ; Nouri Borujerdi, A ; Sharif University of Technology
    Elsevier B. V  2020
    Abstract
    Nowadays, superhydrophobic surfaces have attracted a lot of interest because of the wide range of applications in industries. These surfaces can significantly reduce the drag force due to the formation of air gaps between the substrate and liquid interface. The present review mainly focuses on the very recent progresses in the drag reduction studies using superhydrophobic surfaces. Also, a brief discussion about the mathematical modeling and the theories of superhydrophobic surfaces, natural water repellent surfaces, various fabrication techniques with advantages and disadvantages of each method and different properties of the fabricated surfaces in industrial applications is presented.... 

    Numerical study of the mixing dynamics of trans- And supercritical coaxial jets

    , Article Physics of Fluids ; Volume 32, Issue 12 , 2020 Poormahmood, A ; Farshchi, M ; Sharif University of Technology
    American Institute of Physics Inc  2020
    Abstract
    Characterization of the transcritical coaxial injectors, accounting for the geometrical features and thermodynamics nonlinearities, is of both practical and fundamental importance. In the present study, the interactions and effects of turbulent mixing and pseudo-boiling phenomena are investigated. To do this, the mixing dynamics of bi-shear jets injected under trans- and supercritical conditions has been investigated numerically using the large-eddy simulation technique. The numerical framework provides real-gas thermodynamics and transport properties, using the Peng-Robinson equation-of-state and Chung's models, respectively. The obtained flow quantities are in good agreement with the... 

    Theoretical and experimental study of foam stability mechanism by nanoparticles: Interfacial, bulk, and porous media behavior

    , Article Journal of Molecular Liquids ; Volume 304 , 2020 Suleymani, M ; Ghotbi, C ; Ashoori, S ; Moghadasi, J ; Kharrat, R ; Sharif University of Technology
    Elsevier B.V  2020
    Abstract
    Foam flooding has been applied as a promising method in enhanced oil recovery to obviate the challenges of gas flooding such as fingering, channeling and overriding. However, long-term foam stability is crucial for mobility control. In this work, the effective mechanisms on foam stability in the presence of CaCO3 nanoparticles were assessed both theoretically and experimentally. The static and dynamic behaviors of cationic surfactant (HTAB) foam in the presence of CaCO3 nanoparticles with different hydrophobicity were evaluated. The CaCO3 nanoparticles were treated with a series of long-chain fatty acids to generate a range of wettability. Afterward, the underlying mechanisms were revealed... 

    Phase field approach for nanoscale interactions between crack propagation and phase transformation

    , Article Nanoscale ; Volume 11, Issue 46 , 2019 , Pages 22243-22247 ; 20403364 (ISSN) Jafarzadeh, H ; Levitas, V. I ; Farrahi, G. H ; Javanbakht, M ; Sharif University of Technology
    Royal Society of Chemistry  2019
    Abstract
    The phase field approach (PFA) for the interaction of fracture and martensitic phase transformation (PT) is developed, which includes the change in surface energy during PT and the effect of unexplored scale parameters proportional to the ratio of the widths of the crack surface and the phase interface, both at the nanometer scale. The variation of these two parameters causes unexpected qualitative and quantitative effects: shift of PT away from the crack tip, "wetting" of the crack surface by martensite, change in the structure and geometry of the transformed region, crack trajectory, and process of interfacial damage evolution, as well as transformation toughening. The results suggest... 

    Laboratory evaluation of nitrogen injection for enhanced oil recovery: Effects of pressure and induced fractures

    , Article Fuel ; Volume 253 , 2019 , Pages 607-614 ; 00162361 (ISSN) Fahandezhsaadi, M ; Amooie, M. A ; Hemmati Sarapardeh, A ; Ayatollahi, S ; Schaffie, M ; Ranjbar, M ; Sharif University of Technology
    Elsevier Ltd  2019
    Abstract
    Nitrogen has emerged as a suitable alternative to carbon dioxide for injection into hydrocarbon reservoirs worldwide to enhance the recovery of subsurface energy. Nitrogen typically costs less than CO2 and natural gas, and has the added benefit of being widely available and non-corrosive. However, the underlying mechanisms of recovery following N2 injection into fractured reservoirs that make up a large portion of the world's oil and gas reserves are not well understood. Here we present the laboratory results of N2 injection into carbonate rocks acquired from a newly developed oil reservoir in Iran with a huge N2-containing natural gas reservoir nearby. We investigate the effectiveness of N2...