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    Quantum chemical parameters of some organic corrosion inhibitors, pyridine, 2-picoline 4-picoline and 2,4-lutidine, adsorption at aluminum surface in hydrocholoric and nitric acids and comparison between two acidic media

    , Article Main Group Metal Chemistry ; Volume 26, Issue 6 , 2003 , Pages 349-361 ; 07921241 (ISSN) Monajjemi, M ; Mollaamin, F ; Gholami, M. R ; Yoosbashizadeh, H ; Sadrnezhad, S.K ; Passdar, H ; Sharif University of Technology
    Walter de Gruyter GmbH  2003
    The effect of new corrosion inhibitors, namely pyridine, 2-methylpyridine (2-picoline), 4-methylpyridine (4-picoline), 2,4-dimethylpyridine (2,4-lutidine), on the corrosion of Al-surface in hydrocholoric acid (HCl) and nitric acid (HNO3) was investigated at the HF and B3LYP level using the ab initio 6-3IG and LANL2DZ basis sets from the program package Gaussian 98 (A.7 Public Domain version). The physico-chemical properties of corrosion inhibitors are one of the principal criteria for the determination and selection of inhibitors. The inhibition of the Al-surface in solutions of hydrocholoric acid and nitric acid by some N-heterocyclic compounds has been studied. The calculated results... 

    Hydrogen electrosorption on TiHg alloy in acidic solution

    , Article Journal of Alloys and Compounds ; Volume 432, Issue 1-2 , 2007 , Pages 74-80 ; 09258388 (ISSN) Jafarian, M ; Azizi, O ; Gobal, F ; Mahjani, M. G ; Sharif University of Technology
    Hydrogen evolution and electrosorption on/in TiHg alloy have been investigated in acidic solution using cyclic voltammetry, open circuit potential transient, steady-state polarization, chronopotentiometry and electrochemical impedance measurements. Comparison has been made with pure Ti. Cyclic voltammetry and open circuit potential measurements show that hydrogen absorption into the electrode material occurs during proton discharge. The steady-state polarization curves in the course of positive and negative potential scans illustrate that the formation of absorbed hydrogen slightly improves the electrocatalytic properties of the electrode. The hydrogen diffusion coefficient into the bulk of... 

    Solvent Extraction of Indium from PlS Solution Produced of Zinc Concentrate Leaching

    , M.Sc. Thesis Sharif University of Technology Mobaraki Moghaddam, Mahya (Author) ; Yoozbashizadeh, Hossein (Supervisor)
    Indium is one of the most important metals in electronics and nuclear industry with increasing demand. The most important application of Indium is in the preparation of thin films containing this metal in LCD manufacturing, television, laptops, monitors and CD players. Indium is a rare metal and it has not original mineral. The most important source of it is zinc minerals and regularly obtained from processing by-products of this minerals. The main problem of production of Indium is the simultaneous presence iron ions in the solution of dissolved minerals of zinc. In this project, extraction of Indium from acidic pregnant leaching solution of roasted zinc concentrate contained at less than... 

    Ambient temperature effect on single-bubble sonoluminescence in different concentrations of sulfuric acid solutions

    , Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 85, Issue 1 , January , 2012 ; 15393755 (ISSN) Imani, Kh ; Bemani, F ; Silatani, M ; Sadighi Bonabi, R ; Sharif University of Technology
    The effect of ambient temperature on the parameters of the single-bubble sonoluminescence in sulfuric acid (SA) diluted in water is studied. Using a hydrochemical model, three dominant instabilities of shape, Bjerknes, and diffusion are considered. The phase diagrams of the bubble in the (R 0 - P a) space are presented, and the parametric dependence of the light intensity is discussed. In contrast to water, the calculated thermal-bremsstrahlung mechanism of light emission at the fixed degassing condition of high SA concentrations shows that, with increasing the temperature of aqueous SA solutions, the light intensity increases. However, at diluted SA solutions similar to water, the light... 

    Sonoluminescence radiation from different concentrations of sulfuric acid

    , Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 80, Issue 4 , 2009 ; 15393755 (ISSN) Moshaii, A ; Imani, K ; Silatani, M ; Sharif University of Technology
    Sonoluminescence (SL) radiation from an argon bubble in water and in different concentrations of sulfuric acid has numerically been studied to quantify the effects of vapor pressure and viscosity of the liquid on cavitation luminescence in a liquid with controllable vapor pressure and viscosity. For the solutions containing the noble gas with low partial pressure (about 4 Torr), it is shown that there exists an optimum acid solution in which both the temperature and the intensity of SL radiation become maximum. The calculations show that the maximum SL radiation is achieved from the solution of around 65% (wt.) H2 SO4, which is in agreement with available experimental results. © 2009 The... 

    Investigation into some parameters affecting pectin gel quality

    , Article Scientia Iranica ; Volume 14, Issue 2 , 2007 , Pages 174-179 ; 10263098 (ISSN) Ebrahimi, B ; Alemzadeh, I ; Seifkordi, S. K ; Sharif University of Technology
    Sharif University of Technology  2007
    In this research, gel production from the extracted pectin gel of shahroud sugar beet pulp has been investigated. The pectin extractions were performed in a cold alkaline solution and a hot acid solution, respectively. The effects of different parameters, such as percent of sugar, pectin concentration, calcium content and quantity of peroxidase enzyme, hardness and content of water absorbed by the gel, were studied. Optimum conditions for production of favorable gel, from extracted pectin in this research are, as follows: Percent of sugar (glucose): 15%, peroxidase enzyme content: (pectin unit) 170 pu/g of pectin, pectin concentration (if only gel water uptake is important): 10%, pectin... 

    A simple and fast method for comparison of corrosion inhibition powers between pairs of pyridine derivative molecules

    , Article Corrosion ; Volume 61, Issue 8 , 2005 , Pages 778-783 ; 00109312 (ISSN) Lashgari, M ; Arshadi, M. R ; Parsafar, Gh. A ; Sharif University of Technology
    National Assoc. of Corrosion Engineers International  2005
    Ab initio quantum chemical calculations at the density functional theory (DFT) level were performed on eight pyridine derivative molecules as corrosion inhibitors for iron in an acidic solution. In this regard, the geometry of the molecules were optimized using the B3LYP/6-31G method first, and then interactions of these optimized structures with the iron atom were explored using the B3LYP/LANL1MB method. Two modes of adsorption were considered, i.e., planar adsorption (P) via the pyridine ring and vertical adsorption (V) through a nitrogen atom. The interaction energy was minimized through the variation of the inhibitor molecule-iron atom distance. These minimum energy values, along with... 

    Oxygen-barrier properties of poly(lactic acid)/poly(vinyl acetate-co-vinyl alcohol) blends as biodegradable films

    , Article Journal of Applied Polymer Science ; Volume 125, Issue SUPPL. 2 , September , 2012 , Pages E20-E26 ; 00218995 (ISSN) Razavi, S. M ; Dadbin, S ; Frounchi, M ; Sharif University of Technology
    Wiley  2012
    The oxygen-barrier properties of poly(lactic acid) (PLA)/poly(vinyl acetate-co-vinyl alcohol) [P(VAc-co-VA)] were investigated. P(VAc-co-VA)s with vinyl alcohol (VA) contents of 5, 10, and 15 mol % were prepared with the acid-catalyzed hydrolysis of poly(vinyl acetate). The obtained copolymers with various contents of VA were blended with PLA at 5/95, 10/90, and 15/85 compositions. Films of the blends were prepared by a solution-casting method with chloroform as the cosolvent. Although the blend with 5% VA in the copolymer appeared to be miscible, the blends with 10 and 15% VA content in the copolymer were immiscible, as verified by dynamic mechanical analysis. The oxygen-barrier properties... 

    Three-dimensional Graphene Electrode for Depleted-hetreojunction Quantum Dot Solar Cells

    , Article Procedia Engineering, 28 June 2015 through 3 July 2015 ; Volume 141 , 2016 , Pages 38-46 ; 18777058 (ISSN) Tavakoli, M. M ; Sharif University of Technology
    Elsevier Ltd  2016
    Herein, a simple and novel method was used to synthesize a new structure of graphene which can be called hollow graphene. First, the ZnO-Graphene QDs synthesized by solution method and then ZnO QDs were dissolved from this structure using an acidic solution to obtain hollow structure of graphene. Afterward, this structure was used in PbS QDs solar cell in order to improve the transport of electron and decrease the recombination of the carriers. A power conversion efficiency of 5.3% was obtained using hollow graphene as a fast electron extraction layer due to the enhancement of EQE and current density. The improvement of PCE in this device was corresponded to efficient photosensitized... 

    Environmental effects on the bond at the interface between FRP and wood

    , Article European Journal of Wood and Wood Products ; Volume 76, Issue 1 , 2018 , Pages 163-174 ; 00183768 (ISSN) Yarigarravesh, M ; Toufigh, V ; Mofid, M ; Sharif University of Technology
    Springer Verlag  2018
    The advantages of fiber reinforced polymer (FRP), such as high specific strength, resistance against corrosion and formability, have made it a more acceptable alternative to conventional materials regarding repairing and retrofitting of structures. Although investigations in recent years have proved the concern of civil engineers about the environmental effects on the bond between FRP and concrete or masonry (especially moisture and temperature), only few researches have been reported on FRP-wood interfaces. This research investigated the effect of five different environments on the bond at the interface between FRP and wood. A series of pull-out tests were performed on 375 wood specimens... 

    Reductive leaching of indium from the neutral leaching residue using oxalic acid in sulfuric acid solution

    , Article International Journal of Minerals, Metallurgy and Materials ; Volume 28, Issue 3 , 2021 , Pages 373-379 ; 16744799 (ISSN) Maddah, F ; Alitabar, M ; Yoozbashizadeh, H ; Sharif University of Technology
    University of Science and Technology Beijing  2021
    The present study evaluates the reductive leaching of indium from indium-bearing zinc ferrite using oxalic acid as a reducer in sulfuric acid solution. The effect of main factors affecting the process rate, including the oxalic-acid-to-sulfuric-acid ratio, stirring rate, grain size, temperature, and the initial concentration of synergic acid, was precisely evaluated. The results confirmed the acceptable efficiency of dissolving indium in the presence of oxalic acid. The shrinking-core model with a chemical-reaction-controlled step can correctly describe the kinetics of indium dissolution. On the basis of an apparent activation energy of 44.55 kJ/mol and a reaction order with respect to the... 

    Mechanically stable superhydrophobic nanostructured aluminum mesh with reduced water surface friction

    , Article Nanotechnology ; Volume 32, Issue 19 , 2021 ; 09574484 (ISSN) Taghvaei, E ; Afzali, N ; Taghvaei, N ; Moosavi, A ; Sharif University of Technology
    IOP Publishing Ltd  2021
    Superhydrophobic surfaces demonstrate significant characteristics which make them suitable for a wide variety of applications. In this study, we propose a facile, one-step, and cost-effective anodizing scheme using aluminum nitrate/stearic acid mixture solution to create a superhydrophobic surface on an aluminum mesh. The surface outperforms the surface anodized by the widely used oxalic acid solution in terms of superhydrophobicity and water-surface friction behavior. The proposed surface reduced the friction by 11% on average respective to the surface prepared by oxalic acid. The durability of the introduced superhydrophobic surface has also been investigated. The proposed surface retained... 

    Stability of binary and ternary copper (II) complexes of 2((4-methyl-5-nitro-6-(pyrrolidine-l-yl)pyrimidine-2-yl) amino) propionic acid in aqueous solution

    , Article Scientia Iranica ; Vol. 21, Issue. 6 , 2014 , pp. 2029-2035 ; ISSN: 10263098 Sajadi, S. A. A ; Bagherzadeh, G ; Khaleghian, M ; Kermani, M ; Sharif University of Technology
    The acidity and stability constants of M (MNPPAP) (MNPPAP: 2((4-methyl-5-nitro-6-(pyrrolidine-l-yl)pyrimidine-2-yl)amino)propionic acid) M: Cu2+, Cu (Bpy)2+ (Bpy: 2,2'-Bipyridine), or Cu(Phen) (Phen: 1,10-Phenanthroline) complexes were determined by potentiometric pH titration. It is shown that the stability of the binary Cu (MNPPAP) complex is determined by the basicity of the carboxylate group on one side and amine group on the other side. It is demonstrated that the equilibrium, Cu(Har)2+ (H ar: Heteroaromatic ligand such as Bpy or Phen) + Cu(MNPPAP) ^ Cu(Har)(MNPPAP) + Cu2+, is displacement due to the well known experience that mixed ligand complexes formed by a divalent 3d ion, a... 

    Pure commercial titanium color anodizing and corrosion resistance

    , Article Journal of Materials Engineering and Performance ; Volume 20, Issue 9 , 2011 , Pages 1690-1696 ; 10599495 (ISSN) Karambakhsh, A ; Afshar, A ; Ghahramani, S ; Malekinejad, P ; Sharif University of Technology
    In order to improve titanium corrosion behavior, we can increase the thickness of oxide layer on titanium surface during anodizing process and by electrochemistry. In this research, self-color anodizing of Ti in sulfuric acid was done, and anodizing layers were created in different colors. The highest value of chromaticity was 37.8 for the anodized sample in 10 V, and the lowest value was 8.6 at 15 V. The oxide layer thickness was calculated by optical method (light refraction). The anodic film thickness increased by increasing the anodizing voltage. The highest thickness of anodic film was 190 nm in sulfuric acid solution for the anodized sample in 80 V. Corrosion resistance of anodized Ti... 

    Wear and corrosion properties of electroless nickel composite coatings with PTFE and/or MoS 2 particles

    , Article Journal of Coatings Technology Research ; Volume 8, Issue 4 , 2011 , Pages 527-533 ; 15470091 (ISSN) Mohammadi, M ; Ghorbani, M ; Sharif University of Technology
    This study focuses on the effect of co-deposition of PTFE and/or MoS 2 particles on the morphology, wear, and corrosion properties of electroless nickel coating. The composite coating of EN-PTFE-MoS 2 was heat treated at different temperatures for hardness investigations. The surface morphology of coatings was characterized by scanning electron microscopy. Pin-on-disk and potentiodynamic polarization tests were used to study the tribological and corrosion properties of the coatings, respectively. Results of hardness analysis revealed that the hardness of electroless nickel coatings was increased by the heat treatment, and its maximum was gained at 400°C. Wear investigations showed that... 

    Environmental effects on the bond at the interface of fiber-reinforced polymer and masonry brick

    , Article Journal of Reinforced Plastics and Composites ; Volume 36, Issue 18 , 2017 , Pages 1355-1368 ; 07316844 (ISSN) Toufigh, V ; Yarigarravesh, M ; Mofid, M ; Sharif University of Technology
    This study examined the bond at the interface of masonry bricks and fiber-reinforced polymer when exposed to five environments. Three fabrics (aramid, carbon, and glass) and one type of epoxy resin were used. A total of 375 brick-fiber-reinforced polymer specimens were made using wet lay-up technic and exposed to chemical solutions at four pH values (2.5, 7, 10, and 12.5) and substitute seawater. The effect of dry heat on the bond at the interface was also investigated. Single-lap shear tests were then carried out on the samples after 2, 4, 6, 8, 10, and 13 weeks of exposure. The experimental results indicated that freshwater and seawater had a considerable effect on the bond strength of... 

    Fabrication and characterization of TiO2 deposited black electroless Ni-P solar absorber

    , Article Applied Surface Science ; Volume 496 , 2019 ; 01694332 (ISSN) Razmjoo Khollari, M. A ; Ghorbani, M ; Afshar, A ; Sharif University of Technology
    Elsevier B.V  2019
    Preparing a selective, efficient, and low-cost solar absorber is one of the main challenges in solar to thermal energy conversion. In this paper, black electroless Ni–P (ENi-P) solar absorber has been fabricated, and the effect of nanoporous TiO2 antireflection layer (ARL) on its optical and corrosion properties has been investigated. The optimum black coating was obtained by blackening in 9 M nitric acid solution at 50 °C for 40 s, in which a solar absorptance of 99.3% was achieved. Deposition of TiO2 ARL increased the solar absorptance of coating to 99.7% and addition of 0.8 g Pluronic F127 (F127) as pore former, further increased this value to 99.9% and solar-to-heat efficiency of the... 

    Kinetic and thermodynamic studies of uranium(VI) adsorption using Amberlite IRA-910 resin

    , Article Annals of Nuclear Energy ; Volume 39, Issue 1 , January , 2012 , Pages 42-48 ; 03064549 (ISSN) Rahmati, A ; Ghaemi, A ; Samadfam, M ; Sharif University of Technology
    Thermodynamic and kinetic studies have been carried out on the adsorption of uranium(VI) by Amberlite IRA-910 resin. The adsorption process has been investigated as a function of adsorbate concentration, solution acidity, contact time, adsorbent dosage, and temperature. The experiments were preformed in batch mode, where uranium initial concentration on the solution samples were 185.5, 277.6 and 456.8 (mg/lit), sulfuric acid concentration range was 0.02-9 (mol/lit) and sorbent dosages were 0.2, 0.3 and 0.5 g. Equilibrium isotherm data were analyzed using Freundlich and Dubinin-Radushkevich isotherm models. The results showed that the adsorption process was well described by Freundlich... 

    Hydrolysis kinetics of lead silicate glass in acid solution

    , Article Journal of Nuclear Materials ; Volume 389, Issue 3 , 2009 , Pages 427-431 ; 00223115 (ISSN) Rahimi, R. A ; Sadrnezhaad, Kh ; Raisali, G ; Hamidi, A ; Sharif University of Technology
    Hydrolysis kinetics of the lead silicate glass (LSG) with 40 mol% PbO in 0.5 N HNO3 aqueous acid solution was investigated. The surface morphology and the gel layer thickness were studied by scanning electron microscopy (SEM) micrographs. Energy dispersive X-ray spectroscopy (EDS) and inductively coupled plasma spectroscopy (ICP) were used to determine the composition of the gel layer and the aqueous solution, respectively. The silicon content of the dissolution products was determined by using weight-loss data and compositions of the gel layer and the solution. The kinetic parameters were determined using the shrinking-core-model (SCM) for rate controlling step. The activation energy... 

    Reinforced polydiphenylamine nanocomposite for microextraction in packed syringe of various pesticides

    , Article Journal of Chromatography A ; Volume 1222 , January , 2012 , Pages 13-21 ; 00219673 (ISSN) Bagheri, H ; Ayazi, Z ; Es'haghi, A ; Aghakhani, A ; Sharif University of Technology
    Reinforced polydiphenylamine (PDPA) nanocomposite was synthesized by oxidation of diphenylamine in 4molL-1 sulfuric acid solution containing a fixed amount of carbon nanotubes (CNTs) in the presence of cetyltrimethylammonium bromide (CTAB). The surface characteristic of PDPA and PDPA/CNT nanocomposites was investigated using scanning electron microscopy (SEM). The prepared PDPA/CNT nanocomposite was used as an extraction medium for microextraction in packed syringe (MEPS) of selected pesticides from aquatic environment. The effect of CNT doping level and the presence of surfactant on the extraction capability of nanocomposite was investigated and it was revealed that when 4% (w/w) of CNT in...