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Dimensionless correlation for the prediction of permeability reduction rate due to calcium sulphate scale deposition in carbonate grain packed column
, Article Journal of the Taiwan Institute of Chemical Engineers ; Volume 41, Issue 3 , 2010 , Pages 268-278 ; 18761070 (ISSN) ; Kharrat, R ; Soltanieh, M ; Sharif University of Technology
Abstract
In this work, an experimental and theoretical study has been conducted to investigate the permeability reduction due to CaSO4 scale deposition in packed column porous media. Permeability reduction by calcium sulphate deposition follows a systematic trend considering various important parameters that are affected in this complex process. Hence, a novel dimensionless model has been proposed for the prediction of permeability reduction rate with high accuracy. The developed model is based on the data obtained from glass bead and carbonate grain packed column at low pressure. The proposed model was validated with Berea sandstone cores data at high pressure (100-20,678 kPa), various flow rates...
Electroless plating of palladium on WO3 films for gasochromic applications
, Article Solar Energy Materials and Solar Cells ; Volume 94, Issue 2 , 2010 , Pages 201-206 ; 09270248 (ISSN) ; Tahmasebi Garavand, N ; Mahdavi, S. M ; Iraji Zad, A ; Sharif University of Technology
2010
Abstract
Nowadays, gasochromic Pd/WO3 coatings as optically switchable materials during H2 absorption have become more interesting due to their novel applications in smart windows and gas sensor devices. In this study, WO3 films were fabricated by Pulsed Laser Deposition (PLD) on glass substrates. Using an electroless method, Pd nanoparticles were deposited on the surface of the produced films. The effect of Pd growth time on coloring/bleaching rate was studied for different submerging times (1, 2, 5, 10, 15, 20 and 40 min). The best coloring/bleaching velocity was attained with a growth time of 2 min. The effect of growing time and growth feature of Pd particles was further studied using Scanning...
Investigation of the electrochemical behavior of catechol and 4-methylcatechol in the presence of methyl mercapto thiadiazol as a nucleophile: application to electrochemical synthesis
, Article Journal of Applied Electrochemistry ; Volume 40, Issue 1 , 2010 , Pages 115-122 ; 0021891X (ISSN) ; Rastgar, S ; Sharif University of Technology
Abstract
The present study concerns the electrochemical behavior of catechol and 4-methylcatechol in the presence of 2-mercapto-5-methyl-1,3,4-thiadiazole (MMT) in aqueous medium on the surface of the glassy carbon electrode by means of cyclic voltammetry and controlled-potential coulometry. The oxidation mechanism was deduced from voltammetric and spectrophotometric data. The electro-generation of quinoid intermediates and their subsequent Michael-type reaction with MMT has been investigated as a clean and convenient strategy for the synthesis of corresponding reaction products. In addition, electro-synthesis of Michael addition products has been successfully accomplished by controlled-potential...
Fabrication of CuFe2O4/α-Fe2O3 composite thin films on FTO coated glass and 3-D nanospike structures for efficient photoelectrochemical water splitting
, Article ACS Applied Materials and Interfaces ; Volume 8, Issue 51 , 2016 , Pages 35315-35322 ; 19448244 (ISSN) ; Hussain, S ; Waleed, A ; Tavakoli, M. M ; Wang, Z ; Yang, S ; Fan, Z ; Nadeem, M. A ; Sharif University of Technology
American chemical society
2016
Abstract
Recently, photoelectrochemical conversion (PEC) of water into fuel is attracting great attention of researchers due to its outstanding benefits. Herein, a systematic study on PEC of water using CuFe2O4/ α-Fe2O3 composite thin films is presented. CuFe2O4/ α-Fe2O3 composite thin films were deposited on two different substrates; (1) planner FTO glass and (2) 3-dimensional nanospike (NSP). The films on both substrates were characterized and tested as anode material for photoelectrochemical water splitting reaction. During PEC studies, it was observed that the ratio between two components of composite is crucial and highest PEC activity results were achieved by 1:1 component ratio (CF-1) of...
Au-Pd bimetallic nanoparticle electrodes for direct electroreduction of hexavalent chromium complexes
, Article Australian Journal of Chemistry ; Volume 69, Issue 4 , 2016 , Pages 423-430 ; 00049425 (ISSN) ; Hariri, M. B ; Kushwaha, A ; Dolati, A ; Ghorbani, M ; Goh, G. K. L ; Sharif University of Technology
CSIRO
2016
Abstract
This paper reports a simple, low-cost, and effective electrochemical technique for sensing and reducing CrVI based on a Au-Pd bimetallic nanoparticle (BNP)-decorated indium tin oxide (ITO) conducting glass electrode. It was observed that the Au-Pd BNP-decorated ITO electrode could significantly boost the electrochemical reduction of CrVI when compared with either Au nanoparticle- or Pd nanoparticle-decorated ITO electrodes. These BNP-decorated electrodes exhibited a wide linear concentration range of 0.001-100 μM, a very low detection limit (signal-to-noise ratio = 3) of 0.3 nM, and a high sensitivity of 1.701 μA μM-1. From electrochemical impedance spectroscopy, it was revealed that this...
The effect of sol-gel surface modified silver nanoparticles on the protective properties of the epoxy coating
, Article RSC Advances ; Volume 6, Issue 23 , 2016 , Pages 18996-19006 ; 20462069 (ISSN) ; Haddadi, S. A ; Mahdavian, M ; Sharif University of Technology
Royal Society of Chemistry
2016
Abstract
In this study, the effect of surface modified silver nanoparticles on the corrosion protection of an epoxy coating on mild steel was studied. An organosilane (3-methoxy silyl propyl metacrylate) was used as a surface modifier to increase the dispersability of the inorganic nanoparticles in the organic epoxy coating matrix. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) were used to characterize the surface modified nanoparticles. Differential scanning colorimetry (DSC) was employed to study the effects of modified and unmodified nano-silver on the curing heat and glass transition temperature of the epoxy coatings. Salt spray and electrochemical impedance...
Environmentally responsive surface-modified silica nanoparticles for enhanced oil recovery
, Article Journal of Nanoparticle Research ; Volume 18, Issue 9 , 2016 ; 13880764 (ISSN) ; Mohammadi, A ; Sharif University of Technology
Springer Netherlands
Abstract
Environmentally responsive surface-modified nanoparticles are colloidal nanoparticles coated with, at least, two physicochemically distinct surface groups. Recent advances in the synthesis and production of nanoparticles have enabled the production of environmentally responsive surface-modified nanoparticles with both hydrophilic and hydrophobic surface groups. These nanoparticles act like colloidal surfactants. In this paper, environmentally responsive surface-modified silica nanoparticles are synthesized and used for enhancement of oil recovery. For this purpose, silica nanoparticles are coated with polyethylene glycol chains as hydrophilic agent and propyl chains as hydrophobic agent at...
A novel model for complex permittivity of glass for propagation modeling in millimeter-wave band
, Article Mediterrannean Microwave Symposium, MMS 2009 ; 2009 ; 9781424446643 (ISBN) ; Shishegar, A. A ; Sharif University of Technology
Abstract
In radio channels modelings, the phases and amplitudes of the rays undergo some modifications when they are reflected from or transmitted through a particular material. These reflection and transmission coefficients make use of the electrical properties of the materials, thus, it is essential to know the values of the relative dielectric constant and of the conductivity or the loss tangent of the materials that appear in the propagation environments. In this paper, a theoretical model based on the inter-molecule interactions, has been developed and used to estimate the dielectric parameters of glass. ©2009 IEEE
Electrochemical investigation of electrodeposited platinum nanoparticles on multi walled carbon nanotubes for methanol electro-oxidation
, Article Journal of Chemical Sciences ; Volume 129, Issue 9 , 2017 , Pages 1399-1410 ; 09743626 (ISSN) ; Moakhar, R. S ; Dolati, A ; Sharif University of Technology
Abstract
Abstract: The electrodeposition of platinum nanoparticles (PtNPs) on multiwall carbon nanotubes (MWCNTs)/fluorine-doped tin oxide glass (FTO) was investigated. Nucleation and growth mechanisms were studied via Scharifker and Hills model. Chronoamperometry results clearly show that the electrodeposition processes are diffusion-controlled and the diffusion coefficient is 1.5×10-5cm2/s. The semi-spherical particles with lamellar morphology were observed in 1M H 2SO 4, while a petal shape was discerned in 0.5M H 2SO 4. Also, dispersion, size, and uniformity of PtNPs were investigated, where the finer distribution of PtNPs with the average size less than 100 nm was obtained in 0.5M H 2SO 4...
Interactions near the triple-phase boundaries metal/glass/air in planar solid oxide fuel cells
, Article International Journal of Hydrogen Energy ; Volume 42, Issue 8 , 2017 , Pages 5306-5314 ; 03603199 (ISSN) ; Kokabi, A. H ; Nemati, A ; Zinatlou Ajabshir, S ; Sharif University of Technology
Abstract
The possible interactions near the triple-phase boundaries (TPB) metal/glass/air, and their effects on joint strength are investigated. Two types of samples (joined couples and glass coated coupons) are prepared with the coupon of AISI 430 (nickel plated and uncoated) and a slurry of compliant silicate sealing glass (SCN-1). The joined and coated samples are heated at 850 °C for 1000 h in air. The joined couples are cooled using two different schedules and then tested in uniaxial tension. For investigating the metal-oxides precipitation procedure in glass near the TPB, glass coated coupons are either cooled at the rate of 5 °C min−1 or water-quenched from aging temperature. The mechanical...
A comprehensive study on the fabrication and properties of biocomposites of poly(lactic acid)/ceramics for bone tissue engineering
, Article Materials Science and Engineering C ; Volume 70 , 2017 , Pages 897-912 ; 09284931 (ISSN) ; Hajiali, F ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
The fabrication of a suitable scaffold material is one of the major challenges for bone tissue engineering. Poly(lactic acid) (PLA) is one of the most favorable matrix materials in bone tissue engineering owing to its biocompatibility and biodegradability. However, PLA suffers from some shortcomings including low degradation rate, low cell adhesion caused by its hydrophobic property, and inflammatory reactions in vivo due to its degradation product, lactic acid. Therefore, the incorporation of bioactive reinforcements is considered as a powerful method to improve the properties of PLA. This review presents a comprehensive study on recent advances in the synthesis of PLA-based biocomposites...
Thermodynamic evaluation of adsorption of zinc complex and ZnO nano-layer prepared by tscd method based on langmuir adsorption model
, Article International Journal of Engineering, Transactions B: Applications ; Volume 22, Issue 2 , 2009 , Pages 179-184 ; 1728-144X (ISSN) ; Sadrnezhaad, S. K ; Sharif University of Technology
Materials and Energy Research Center
2009
Abstract
Zinc oxide thin films were deposited on soda-lime glass substrates from an aqueous zinc- containing complex by two-stage chemical deposition (TSCD) method. Longmuir adsorption model showed that the adsorption of atoms on the surface of the substrate was typically physical. The relation between the fractional coverage, θ, with the equilibrium constant of the adsorption reaction was nonlinear indicating that the adsorption was non-ideal. The percentage of porosity, 1-θ, of the thin layer was determined as a function of Zn 2+ concentration of the solution. By application of XRD technique, it was shown that pure crystalline ZnO of controllable thickness could be deposited by TSCD method on the...
The effect of elevated temperatures on the tensile performance of GFRP and CFRP sheets
, Article Construction and Building Materials ; Volume 190 , 2018 , Pages 38-52 ; 09500618 (ISSN) ; Pournamazian Najafabadi, E ; Houshmand Khaneghahi, M ; Vatani Oskouei, A ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
In this study, the effects of fiber type (i.e., carbon and glass fibers) and intumescent paint on the tensile performance of fiber reinforced polymer (FRP) sheets at elevated temperatures are investigated. For this purpose, a series of tensile tests were conducted on the glass and carbon fiber reinforced polymer (GFRP and CFRP) sheets, with and without intumescent fire retardant paint, at different elevated temperatures. The studied temperatures ranged from 25 °C to 600 °C. Scanning electron microscopy was also used to examine the effects of elevated temperatures on FRP sheets and the fire protecting mechanism of the intumescent paint. Based on the test results, the tensile strength of the...
Ultrasensitive detection of cancer biomarkers using conducting polymer/electrochemically reduced graphene oxide-based biosensor: Application toward BRCA1 sensing
, Article Sensors and Actuators, B: Chemical ; Volume 266 , 2018 , Pages 160-169 ; 09254005 (ISSN) ; Salimian, R ; Sharif University of Technology
Elsevier B.V
2018
Abstract
Breast Cancer (BRCA) is the most common threat in women worldwide. Increasing death rate of diagnosed cases is the main leading cause of designing specific genosensors for BRCA − related cancer detection. In the present study, an ultrasensitive label − free electrochemical DNA (E − DNA) sensor based on conducting polymer/reduced graphene − oxide platform has been developed for the detection of BRCA1 gene. An electrochemical method was applied as a simple and controllable technique for the electrochemical reduction of graphene oxide and also, electro − polymerization of pyrrole − 3 − carboxylic acid monomer. The results of the present work show that the polymer − coated reduced graphene −...
Interrelation between mechanical response, strain field, and local free volume evolution in glassy polymers: seeking the atomistic origin of post-yield softening
, Article Express Polymer Letters ; Volume 12, Issue 1 , January , 2018 , Pages 2-12 ; 1788618X (ISSN) ; Bagheri, R ; Gigl, T ; Hugenschmidt, C ; Raps, D ; Altstadt, V ; Sharif University of Technology
BME-PT and GTE
2018
Abstract
A set of complementary experiments are used for the first time to elucidate the interrelation between the mechanical properties, the strain field, and the free volume evolution during non-homogenous compression of aglassy polymer. Two sets of quenched and annealed polystyrene samples, having different free volume histories, are notched and exposed to compression. The variation of both the strain field and the free volume are measured on a microscopic scale via digital image correlation in case of strain and Doppler broadening spectroscopy of positron annihilation line in case of free volume measurements. Eventually, the interplay between the local evolution of free-volume, the local strain...
Nanotextured spikes of α-Fe2O3/NiFe2O4 composite for efficient photoelectrochemical oxidation of water
, Article Langmuir ; Volume 34, Issue 12 , 2018 , Pages 3555-3564 ; 07437463 (ISSN) ; Tavakoli, M. M ; Waleed, A ; Virk, U. S ; Yang, S ; Waseem, A ; Fan, Z ; Nadeem, M. A ; Sharif University of Technology
American Chemical Society
2018
Abstract
We demonstrate for the first time the application of p-NiFe2O4/n-Fe2O3 composite thin films as anode materials for light-assisted electrolysis of water. The p-NiFe2O4/n-Fe2O3 composite thin films were deposited on planar fluorinated tin oxide (FTO)-coated glass as well as on 3D array of nanospike (NSP) substrates. The effect of substrate (planar FTO and 3D-NSP) and percentage change of each component (i.e., NiFe2O4 and Fe2O3) of composite was studied on photoelectrochemical (PEC) water oxidation reaction. This work also includes the performance comparison of p-NiFe2O4/n-Fe2O3 composite (planar and NSP) devices with pure hematite for PEC water oxidation. Overall, the nanostructured...
Acoustic emission-based methodology to evaluate delamination crack growth under quasi-static and fatigue loading conditions
, Article Journal of Nondestructive Evaluation ; Volume 37, Issue 1 , March , 2018 ; 01959298 (ISSN) ; Ahmadi Najafabadi, M ; Mohammadi, K ; Fotouhi, M ; Hosseini Toudeshky, H ; Mohammadi, R ; Sharif University of Technology
Springer New York LLC
2018
Abstract
The aim of this study was to investigate the applicability of acoustic emission (AE) technique to evaluate delamination crack in glass/epoxy composite laminates under quasi-static and fatigue loading. To this aim, double cantilever beam specimens were subjected to mode I quasi-static and fatigue loading conditions and the generated AE signals were recorded during the tests. By analyzing the mechanical and AE results, an analytical correlation between the AE energy with the released strain energy and the crack growth was established. It was found that there is a 3rd degree polynomial correlation between the crack growth and the cumulative AE energy. Using this correlation the delamination...
Electrochemical impedance studies of methanol oxidation on GC/Ni and GC/NiCu electrode
, Article International Journal of Hydrogen Energy ; Volume 34, Issue 2 , 2009 , Pages 859-869 ; 03603199 (ISSN) ; Jafarian, M ; Forouzandeh, F ; Gobal, F ; Mahjani, M. G ; Sharif University of Technology
2009
Abstract
The electro-oxidation of methanol on nickel and nickel-copper alloy modified glassy carbon electrodes (GC/Ni and GC/NiCu) in a 1 M NaOH solution at different concentrations of methanol was studied by the method of ac-impedance spectroscopy. Two semicircles in the first quadrant of a Nyquist diagram were observed for electro-oxidation of methanol on GC/Ni corresponding to charge transfer resistance and adsorption of intermediates. Electro-oxidation of methanol on GC/NiCu shows negative resistance in impedance plots as signified by semi-circles terminating in the second quadrant. The impedance behavior shows different patterns at different applied anodic potential. The influence of the...
Electrochemical study of Azathioprine at thin carbon nanoparticle composite film electrode
, Article Electrochemistry Communications ; Volume 11, Issue 7 , 2009 , Pages 1425-1428 ; 13882481 (ISSN) ; Ghalkhani, M ; Sharif University of Technology
2009
Abstract
Thin carbon nanoparticle/Nafion film (CNP/N), as a novel electrode material, is formed on the surface of the glassy carbon electrode in a simple solvent evaporation process. The electrochemical behavior of Azathioprine (Aza) at the CNP/N-modified electrode is investigated in detail by the means of cyclic voltammetry. During the electrochemical reduction of Aza, an irreversible cathodic peak is appeared. Cyclic voltammetric studies indicated that the reduction process has an irreversible and adsorption-like behavior. The observed reduction peak is attributed to a four-electron process referring to the reduction of nitro group to the corresponding hydroxylamine. The prepared electrode showed...
Assessment of plain and glass fiber-reinforced concrete under impact loading: a new approach via ultrasound evaluation
, Article Journal of Nondestructive Evaluation ; Volume 38, Issue 4 , 2019 ; 01959298 (ISSN) ; Toufigh, V ; Sharif University of Technology
Springer
2019
Abstract
Impact loading leads to micro-crack formation that can compromise the performance of the concrete. The purpose of this paper is to evaluate plain concrete and fiber-reinforced concrete specimens using ultrasound methods under impact loading. These specimens were prepared and subjected to impact loading. Ultrasound tests were performed at different stages of impact loading on each specimen. The loading continued until cracks on the surface of the specimens were observed. Investigations were performed for both plain concrete and fiber-reinforced concrete to establish a correlation between ultrasound response characteristics, and the damage caused by impact loading due to the energy of blows...