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    Influence of double aging on microstructure and yield strength of AEREX ™ 350

    , Article Materials Science and Engineering A ; Volume 534 , 2012 , Pages 547-551 ; 09215093 (ISSN) Kermajani, M ; Sharif University of Technology
    Abstract
    Age hardening behavior of selected samples of AEREX ™ 350, a nickel-cobalt based superalloy, was investigated in this article. The relationship between the microstructure and mechanical properties was elucidated using hardness and compression testing methods and optical, scanning and transmission electron microscopy techniques. It was found that the microstructure is sensitive to the temperature of the solution and the aging treatments. This approach may be used to optimize the microstructure of the alloy for different applications  

    Effect of 10Ce-TZP/Al2O3 nanocomposite particle amount and sintering temperature on the microstructure and mechanical properties of Al/(10Ce-TZP/Al2O3) nanocomposites

    , Article Materials and Design ; Volume 50 , 2013 , Pages 85-91 ; 02641275 (ISSN) Soltani, N ; Pech Canul, M. I ; Bahrami, A ; Sharif University of Technology
    Elsevier Ltd  2013
    Abstract
    A zirconia/alumina nanocomposite stabilized with cerium oxide (Ce-TZP/Al2O3 nanocomposite) can be a good substitute as reinforcement in metal matrix composites. In the present study, the effect of the amount of 10Ce-TZP/Al2O3 particles on the microstructure and properties of Al/(10Ce-TZP/Al2O3) nanocomposites was investigated. For this purpose, aluminum powders with average size of 30μm were ball-milled with 10Ce-TZP/Al2O3 nanocomposite powders (synthesized by aqueous combustion) in varying amounts of 1, 3, 5, 7, and 10wt.%. Cylindrical-shape samples were prepared by pressing the powders at 600MPa for 60min while heating at 400-450°C. The specimens were then characterized by scanning and... 

    Morphology transition control of polyaniline from nanotubes to nanospheres in a soft template method

    , Article Polymer International ; Volume 64, Issue 1 , June , 2015 , Pages 88-95 ; 09598103 (ISSN) Pirhady Tavandashti, N ; Ghorbani, M ; Shojaei, A ; Sharif University of Technology
    John Wiley and Sons Ltd  2015
    Abstract
    A soft template route is reported for the fabrication of polyaniline nanospheres via the oxidative polymerization of aniline in the presence of β-naphthalenesulfonic acid (β-NSA) as both surfactqant and dopant, and ammonium persulfate as oxidant at 2-5°C. Control over the morphology and size of the nanoparticles was achieved by changing the reaction medium via addition of an organic cosolvent (i.e. ethanol or ethylene glycol) and by controlling the concentrations of aniline and β-NSA and the molar ratio of β-NSA to aniline. By this means the size of the β-NSA-aniline micelles and the way that aniline monomer interacts with the micelles were controlled. In fact the lower dielectric constant... 

    Copper immobilized onto polymer-coated magnetic nanoparticles as recoverable catalyst for 'click' reaction

    , Article Applied Organometallic Chemistry ; 2016 ; 02682605 (ISSN) Banan, A ; Bayat, A ; Valizadeh, H ; Sharif University of Technology
    John Wiley and Sons Ltd  2016
    Abstract
    Copper supported on polymer-coated magnetic nanoparticles was designed and synthesized as a separable heterogeneous catalyst. The catalyst was fully characterized using several techniques such as Fourier transform infrared and energy-dispersive X-ray spectroscopies, scanning and transmission electron microscopies, X-ray diffraction, vibrating sample magnetometry, thermogravimetric analysis and inductively coupled plasma atomic emission spectrometry. All results showed that copper was successfully supported on the polymer-coated magnetic nanoparticles. Also, results showed that the synthesized material can be used as an efficient catalyst for the preparation of a series of 1,4-disubstituted... 

    Highly stable magnetically separable copper nanocatalyst as an efficient catalyst for C(sp2)-C(sp) and C(sp2)-C(sp2) cross-coupling reactions

    , Article Applied Organometallic Chemistry ; 2016 ; 02682605 (ISSN) Keypour, H ; Balali, M ; Nejat, R ; Bagherzadeh, M ; Sharif University of Technology
    John Wiley and Sons Ltd  2016
    Abstract
    A copper catalyst has been explored as an efficient and recyclable catalyst to effect Sonogashira and Suzuki cross-coupling reactions. After modification of 2-(((piperazin-1-ylmethyl)imino)methyl)phenol (PP) on the surface of amorphous silica-coated iron oxide (Fe3O4@SiO2@Cl) magnetic core-shell nanocomposite, copper(II) chloride was employed to synthesize the Fe3O4@SiO2@PP-Cu catalyst, affording a copper loading of 1.52 mmol g-1. High yield, low reaction times, non-toxicity and recyclability of the catalyst are the main merits of this protocol. The catalyst was characterized using Fourier transform infrared, X-ray photoelectron, energy-dispersive X-ray and inductively coupled plasma optical... 

    An investigation on the fatigue fracture of P/M Al-SiC nanocomposites

    , Article Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science ; Volume 44, Issue 6 , 2013 , Pages 2662-2671 ; 10735623 (ISSN) Ghasemi Yazdabadi, H ; Ekrami, A ; Kim, H. S ; Simchi, A ; Sharif University of Technology
    Abstract
    A tensile-compression fatigue response of Al matrix composites containing different amount of SiC nanoparticles (50 nm diameter) up to 6 vol. pct was studied. The nanocomposite powders were prepared by a powder metallurgy (P/M) route consisting of mechanical alloying, hot extrusion, and hot closed-die forging. The microstructure of the materials was evaluated by optical microscopy, scanning and transmission electron microscopies, and electron backscattered diffraction. A fine distribution of the nanoparticles in submicron and ultrafine grains was obtained. The low cycle fatigue behavior was examined in stress control mode under fully reversed tension-compression cycle at 1 Hz up to 1000... 

    Immobilization of copper ions onto α-amidotriazole-functionalized magnetic nanoparticles and their application in the synthesis of triazole derivatives in water

    , Article Applied Organometallic Chemistry ; Volume 30, Issue 6 , 2016 , Pages 488-493 ; 02682605 (ISSN) Matloubi Moghaddam, F ; Ayati, S. E ; Firouzi, H. R ; Ghorbani, F ; Sharif University of Technology
    John Wiley and Sons Ltd 
    Abstract
    A new heterogeneous copper catalyst was synthesized by immobilization of copper ions onto magnetic nanoparticles with a new ligand based on triazole. The catalyst was characterized using scanning and transmission electron microscopies, atomic absorption and Fourier transform infrared spectroscopies, and thermogravimetric, elemental and energy-dispersive X-ray analyses. The results confirmed that a good level of organic groups was immobilized on the magnetic nanoparticles. Huisgen cycloaddition reaction was chosen as a model reaction for the investigation of catalyst activity under green conditions. Phenylacetylene and benzyl bromide derivatives were used for the synthesis of triazoles. The... 

    Adsorptive removal of petroleum hydrocarbons from aqueous solutions by novel zinc oxide nanoparticles grafted with polymers

    , Article Petroleum Science and Technology ; Volume 34, Issue 8 , 2016 , Pages 778-784 ; 10916466 (ISSN) Salehi, B ; Hasani, A. H ; Ahmad Panahi, H ; Borghei, S. M ; Sharif University of Technology
    Taylor and Francis Inc 
    Abstract
    Zinc oxide nanoparticles were synthesized and modified by a three-stage method. Elemental analysis, Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning and transmission electron microscopy, and Brunauer–Emmett–Teller method were applied to characterize the nanoparticles. These nanoparticles were evaluated for toluene adsorption from aqueous solutions as a representative of petroleum hydrocarbon removal. The optimum adsorption condition achieved at pH of 6 and contact time of 30 min. The adsorption isotherms were fitted to the Langmuir model. The measured adsorption capacity was 12.8 mg g−1. This study demonstrated that these nanoparticles could be used as an... 

    Highly stable magnetically separable copper nanocatalyst as an efficient catalyst for C(sp2)–C(sp) and C(sp2)–C(sp2) cross-coupling reactions

    , Article Applied Organometallic Chemistry ; Volume 31, Issue 9 , 2017 ; 02682605 (ISSN) Keypour, H ; Balali, M ; Nejat, R ; Bagherzadeh, M ; Sharif University of Technology
    Abstract
    A copper catalyst has been explored as an efficient and recyclable catalyst to effect Sonogashira and Suzuki cross-coupling reactions. After modification of 2-(((piperazin-1-ylmethyl)imino)methyl)phenol (PP) on the surface of amorphous silica-coated iron oxide (Fe3O4@SiO2@Cl) magnetic core–shell nanocomposite, copper(II) chloride was employed to synthesize the Fe3O4@SiO2@PP-Cu catalyst, affording a copper loading of 1.52 mmol g−1. High yield, low reaction times, non-toxicity and recyclability of the catalyst are the main merits of this protocol. The catalyst was characterized using Fourier transform infrared, X-ray photoelectron, energy-dispersive X-ray and inductively coupled plasma optical... 

    Copper immobilized onto polymer-coated magnetic nanoparticles as recoverable catalyst for ‘click’ reaction

    , Article Applied Organometallic Chemistry ; Volume 31, Issue 5 , 2017 ; 02682605 (ISSN) Banan, A ; Bayat, A ; Valizadeh, H ; Sharif University of Technology
    Abstract
    Copper supported on polymer-coated magnetic nanoparticles was designed and synthesized as a separable heterogeneous catalyst. The catalyst was fully characterized using several techniques such as Fourier transform infrared and energy-dispersive X-ray spectroscopies, scanning and transmission electron microscopies, X-ray diffraction, vibrating sample magnetometry, thermogravimetric analysis and inductively coupled plasma atomic emission spectrometry. All results showed that copper was successfully supported on the polymer-coated magnetic nanoparticles. Also, results showed that the synthesized material can be used as an efficient catalyst for the preparation of a series of 1,4-disubstituted... 

    Effect of dwell time on joint interface microstructure and strength of dissimilar friction stir spot-welded al-5083 and st-12 alloy sheets

    , Article Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science ; Volume 48, Issue 4 , 2017 , Pages 1744-1758 ; 10735623 (ISSN) Fereiduni, E ; Movahedi, M ; Kokabi, A. H ; Najafi, H ; Sharif University of Technology
    Springer Boston  2017
    Abstract
    Joining of Al-5083 alloy sheet to St-12 steel sheet was performed using a new friction stir spot welding (FSSW) technique in which the tool pin tip did not enter lower steel sheet. Effect of dwell time on the microstructure and mechanical properties of the joints was studied by various methods including microhardness measurements, shear test, stereo and light microscopy as well as scanning and transmission electron microscopy (SEM and TEM). Results indicated that compared to the conventional FSSW process, stronger joints can be achieved by this FSSW technique. Cross-sectional observation of the failed specimens indicated the occurrence of final fracture from the circumference of the tool pin... 

    Suzuki–Miyaura coupling reaction in water in the presence of robust palladium immobilized on modified magnetic Fe3O4 nanoparticles as a recoverable catalyst

    , Article Applied Organometallic Chemistry ; Volume 32, Issue 2 , 2018 ; 02682605 (ISSN) Dadras, A ; Naimi Jamal, M. R ; Moghaddam, F. M ; Ayati, S. E ; Sharif University of Technology
    John Wiley and Sons Ltd  2018
    Abstract
    Aryl halides and especially inactive aryl chlorides were coupled to benzenoid aromatic rings in a Suzuki–Miyaura coupling reaction in the absence of organic solvents and toxic phosphine ligands. The reaction was catalysed by a recoverable magnetic nanocatalyst, Pd@Fe3O4, in aqueous media. This method is green, and the catalyst is easily removed from the reaction media using an external magnetic field and can be re-used at least 10 times without any considerable loss in its activity. The catalyst was characterized using scanning and transmission electron microscopies, thermogravimetric analysis, inductively coupled plasma spectroscopy, Fourier transform infrared spectroscopy, CHN analysis,... 

    Effect of an anodizing pre-treatment on AA 5052 alloy/polypropylene joining by friction stir spot welding

    , Article Materials Science and Engineering B: Solid-State Materials for Advanced Technology ; Volume 245 , 2019 , Pages 107-112 ; 09215107 (ISSN) Aliasghari, S ; Skeldon, P ; Zhou, X ; Hashimoto, T ; Sharif University of Technology
    Elsevier Ltd  2019
    Abstract
    A study has been carried out of the effect of an anodizing pre-treatment in a sulphuric acid electrolyte on the strength of AA 5052 alloy/polypropylene joints prepared using friction stir spot welding. Lap-shear tests were used to determine the joint strength. Comparisons were made with joints pre-treated using sand blasting. The failed specimens were examined by scanning and transmission electron microscopy. Anodizing improved the strength of the joints by a factor of about 6 compared with sandblasting. For the anodizing pre-treated joints, melted polymer infiltrated deeply within the nanoporous anodic film, forming a strong polymer-film bond. Joint failure occurred by ductile tearing of... 

    Production of silver nanoparticles by electromagnetic levitation gas condensation

    , Article Chemical Engineering Journal ; Volume 168, Issue 1 , March , 2011 , Pages 441-445 ; 13858947 (ISSN) Malekzadeh, M ; Halali, M ; Sharif University of Technology
    2011
    Abstract
    Electromagnetic levitation gas condensation (ELGC) method was used to synthesize silver nanoparticles (NPs). Silver droplets were melted and levitated stably at about 1130°C with appropriate flat coils in a 10mm OD silica tube. High purity argon, nitrogen and helium were employed as carrier gases and cooling media. Morphology and particle size of the products were investigated by scanning and transmission electron microscopy (SEM and TEM), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX) and dynamic light scattering (DLS). The DLS, SEM and TEM studies demonstrated narrow size distribution of spherical shape silver NPs with mean particle size of about 60, 50 and 30nm... 

    Study of molecular conformation and activity-related properties of lipase immobilized onto core-shell structured polyacrylic acid-coated magnetic silica nanocomposite particles

    , Article Langmuir ; Volume 32, Issue 13 , 2016 , Pages 3242-3252 ; 07437463 (ISSN) Esmaeilnejad Ahranjani, P ; Kazemeini, M ; Singh, G ; Arpanaei, A ; Sharif University of Technology
    American Chemical Society 
    Abstract
    A facile approach for the preparation of core-shell structured poly(acrylic acid) (PAA)-coated Fe3O4 cluster@SiO2 nanocomposite particles as the support materials for the lipase immobilization is reported. Low- or high-molecular-weight (1800 and 100 000, respectively) PAA molecules were covalently attached onto the surface of amine-functionalized magnetic silica nanoacomposite particles. The successful preparation of particles were verified by scanning transmission electron microscopy (STEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA), zeta potential measurement, and Fourier-transform infrared (FTIR) techniques. Once lipase is covalently... 

    Pt nanoparticles decorated Bi-doped TiO2 as an efficient photocatalyst for CO2 photo-reduction into CH4

    , Article Solar Energy ; Volume 211 , 15 November , 2020 , Pages 100-110 Moradi, M ; Khorasheh, F ; Larimi, A ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    Pt@Bi-TiO2 photocatalysts with different Bi (0–5 wt%) and Pt (0–2 wt%) contents were prepared by a two-step sol-gel and photo-deposition technique and were used in photo-reduction of CO2. The synthesized catalysts were characterized by X-ray powder diffraction (XRD), UV–Vis diffuse reflectance spectroscopy (DRS), scanning and transmission electron microscopy (SEM and TEM), nitrogen sorption measurement (BET), Raman spectroscopy, Electron paramagnetic resonance (EPR) spectroscopy and photoluminescence spectroscopy (PL). CO2 photo-reduction results revealed that the introduction of Bi into TiO2 structure and subsequent loading of Pt on its surface significantly increased the methane yield.... 

    Synthesis and characterization of molybdenum (VI) complex immobilized on polymeric Schiff base-coated magnetic nanoparticles as an efficient and retrievable nanocatalyst in olefin epoxidation reactions

    , Article Applied Organometallic Chemistry ; Volume 34, Issue 3 , 2020 Mortazavi Manesh, A ; Bagherzadeh, M ; Sharif University of Technology
    John Wiley and Sons Ltd  2020
    Abstract
    In this study, a new polymeric functionalized magnetic nanocatalyst containing a molybdenum Schiff base complex was prepared using a few consecutive steps. Poly (methylacrylate)-coated magnetic nanoparticles were synthesized via radical polymerization of methyl acrylate onto modified magnetic nanoparticles followed by the amidation of the methyl ester groups with hydrazine. Polymeric functionalization efficiently provides the advantage that more catalytic units can be grafted on the surface of magnetic nanoparticles. The functionalization process was continued with salicylaldehyde which introduced Schiff base groups on to the surface of the polymeric support. In the final step, the desired...