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    Theoretical model for evaluating the threshold reduction in roll bonding of Al/Al 2O 3/Al laminations

    , Article Metals and Materials International ; Volume 18, Issue 5 , 2012 , Pages 827-832 ; 15989623 (ISSN) Rezayat, M ; Akbarzadeh, A ; Sharif University of Technology
    Springer  2012
    Roll bonding is the most important stage of the accumulative roll bonding process, which is used to produce high strength composites. The presence of a particle layer at the interface alters the bonding condition and increases the threshold reduction for the commencement of bonding. In this study, the bonding mechanism in presence of powder at the interface is analyzed and a theoretical model is proposed to predict the required threshold reduction in warm roll bonding of commercially pure aluminum sheets as a function of amount of alumina particles at the interface. The model considers the rolling parameters and the effect of amount and size of particles by defining some constants, which are... 

    Roll bonding behaviour of Al-3003/Al-4043 and Al-3003/Zn sheets

    , Article Metals and Materials International ; Volume 17, Issue 4 , 2011 , Pages 665-670 ; 15989623 (ISSN) Movahedi, M ; Kokabi, A. H ; Madaah Hosseini, H. R ; Kiani, M ; Sharif University of Technology
    In the present study, the roll bonding behaviour of Al-3003/Al-4043 and Al-3003/Zn sheets were compared. The bi-layer sheets were produced by a roll bonding process at different reductions in thickness and rolling temperatures. The joint strengths of the sheets were evaluated by peel and bend testing before and after supplemental annealing treatment. The peeled surfaces were examined using a scanning electron microscope. The results indicated that the Al-3003/Al-4043 sheets were bonded with higher joint strength and lower threshold reductions in thickness with respect to the Al-3003/Zn sheets. In contrast to the Al-3003/Zn sheets, significant improvement was observed in the joint strength of... 

    Investigation and Synthesis of Zn-Ni-Mn Three Cationic Electrophosphate Coating

    , M.Sc. Thesis Sharif University of Technology Alimi, Zahra (Author) ; Ghorbani, Mohamad (Supervisor)
    The purpose of this study was to create a three-cationic electro phosphate coating of zinc-nickel-manganese by cathodic method and to investigate the effect of operating variables on the properties of zinc-nickel-manganese tri-cationic electro phosphate coating. Hence, the effects of variables such as coating acidity, coating thickness, coating temperature, coating time and concentration of manganese were studied in the bath on the properties such as coating morphology, corrosion resistance, coating thickness. Coating morphology was characterized by scanning electron microscopy and corrosion resistance by polarization test. The pH values of 1.4, 1.8, 2 and 2.2 were selected, and the results... 

    Taguchi optimized synthesis of collagen-g-poly(acrylic acid)/kaolin composite superabsorbent hydrogel

    , Article European Polymer Journal ; Volume 44, Issue 4 , 2008 , Pages 1209-1216 ; 00143057 (ISSN) Pourjavadi, A ; Ayyari, M ; Amini Fazl, M. S ; Sharif University of Technology
    A novel biopolymer-based hydrogel composite was synthesized through chemical crosslinking by graft copolymerization of partially neutralized acrylic acid onto the hydrolyzed collagen. The Taguchi method, a robust experimental design, was employed for the optimization of the synthesis based on the swelling capacity of the hydrogels. This method was applied for the experiments and standard L16 orthogonal array with five factors and four levels. In the synthesis of the composite superabsorbent, N,N′-methylene bisacrylamide (MBA) as crosslinker, ammonium persulfate (APS) as initiator, acrylic acid (AA) as monomer, neutralization percent (NU), and collagen/kaolin weight ratio were used as... 

    Structural changes and surface activities of ethylbenzene dehydrogenation catalysts during deactivation

    , Article Applied Catalysis A: General ; Volume 326, Issue 2 , 2007 , Pages 143-151 ; 0926860X (ISSN) Baghalha, M ; Ebrahimpour, O ; Sharif University of Technology
    Industrial dehydrogenation of ethylbenzene to styrene is performed using potassium-promoted iron oxide catalyst. Many attempts have been made to understand the deactivation mechanism of the catalyst based on the chemical differences between the fresh and used catalysts. In the present work, in addition to the effect of chemical changes, the effect of structural changes of the internal areas on the catalyst activity was investigated. A fresh and used commercial catalyst from an industrial reactor which had been continuously used for two years under severe conditions (LHSV = 1 h-1, T = 610 °C, mass ratio of steam to ethylbenzene = 1.2, P = 1.2 atm) was studied. Nitrogen adsorption, Hg... 

    Sorption kinetics of oil spill by sorbent mineral material (expanded per lite)

    , Article CHISA 2006 - 17th International Congress of Chemical and Process Engineering, Prague, 27 August 2006 through 31 August 2006 ; 2006 ; 8086059456 (ISBN); 9788086059457 (ISBN) Safekordi, A. A ; Alihosseini, A ; Bastani, D ; Taghikhani, V ; Ordookhani, G ; Sharif University of Technology
    The present study examined the sorption capacity and sorption kinetics of four-type perlite for oil spills clean up. These four types are different on their porous space, expansion ability and special surface area. The tests were done both in static and dynamic methods. Experiments showed that the perlite spread on oil spill rapidly and floated on the surface of oil spill because of its low density (80-180 kg/m3). Scanning Electron Micrograph (SEM) of a typical structure of expanded perlite showed that it of high porous space. Sorption kinetic of oil spill into porous expanded perlite was evaluated by weight increase of crude oil with sorption time. According to kinetic study sorption of oil... 

    Co surface modification by bias sputtering in Cu/Co(Vb)/NiO/ Si(100) magnetic multilayer structures

    , Article Physica Status Solidi C: Conferences ; Volume 1, Issue 7 , 2004 , Pages 1744-1747 ; 16101634 (ISSN) Moshfegh, A. Z ; Sangpour, P ; Sharif University of Technology
    To investigate the Ta/Co/Cu/Co/NiO/Si(100) spin valve structure, fabrication and characterization of the Cu/Co/NiO/Si(100) system was studied for further understanding the structure. The system was grown by employing combinative DC sputtering-evaporation technique. Nickel oxide with a thickness of about 30 nm was deposited on Si(100) substrate using thermal evaporation technique.The cobalt film, then, with a thickness of about 3 nm was grown by DC sputtering under various applied negative bias voltages ranging from 0 to - 80 V. The optimum bias voltage (Vb = -60 V) for the growth of Co layer was determined by atomic force microscopy (AFM), four-point probe sheet measurement (Rs) and scanning... 

    Fabrication of BSCCO thin films using sputtering technique

    , Article Physica Status Solidi C: Conferences ; Volume 1, Issue 7 , 2004 , Pages 1895-1898 ; 16101634 (ISSN) Salamati, H ; Kameli, P ; Akhavan, M ; Sharif University of Technology
    Investigation of BSCCO 2223 phase formation in superconducting thin films of Bi-based cuprates deposited on MgO substrate is reported. A series of films were made by in situ dc-magnetron sputtering method and another series were made by ex situ rf-magnetron sputtering technique. Same target have been used in both technique. In the case of the ex situ method, the films were annealed for different period of time at 800°C, and in the case of in situ method, the films were deposited at different temperature substrate. The influence of annealing time and the temperature of the substrate on the quality and the phase formation for ex situ and in situ method have studied, respectively. The results... 

    An electrospun magnetic nanocomposite for a facile micro-scaled analysis approach

    , Article Analytical Methods ; Vol. 6, issue. 15 , 2014 , Pages 5838-5846 ; ISSN: 17599660 Bagheri, H ; Roostaie, A ; Daliri, R ; Sharif University of Technology
    A magnetic polyurethane (PU) nanocomposite was synthesized by an electrospinning technique and applied for isolation and preconcentration of fluoxetine from aquatic and biological samples. The nanocomposite was electrospun using a PU polymer solution containing the dispersed magnetic nanoparticles. The magnetic properties of iron nanoparticles, along with the use of an electrospinning technique, led to the formation of a suitable sorbent toward isolation of fluoxetine. The magnetic PU nanofibers could be subsequently removed from the sample solution by applying a permanent magnet. The scanning electron microscopy (SEM) image of the magnetic PU nanofibers confirms that their diameters are in... 

    In situ preparation and property investigation of polypropylene/fumed silica nanocomposites

    , Article Polymer Composites ; Vol. 35, issue. 1 , January , 2014 , pp. 37-44 ; ISSN: 02728397 Azinfar, B ; Ahmad Ramazani, S. A ; Jafariesfad, N ; Sharif University of Technology
    We present the preparation of polypropylene (PP)/fumed silica (FS) nanocomposites via in situ polymerization in this article. The approach includes preparation and utilization of a bisupported Ziegler-Natta catalytic system in which magnesium ethoxide and FS are used as conjugate supports of the catalyst. Catalyst preparation and polymerization processes are carried out in the slurry phase and under argon atmosphere. Scanning electron microscopy images show a good dispersion of the FS throughout the PP matrix. Results from differential scanning calorimetry reveal that the crystallization temperature of prepared nanocomposites increases by increasing FS loading. Also, crystal content of... 

    Microstructural evolution and fracture behavior of friction-stir-welded Al-Cu laminated composites

    , Article Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science ; Vol. 45, issue. 1 , 2014 , pp. 361-370 Beygi, R ; Kazeminezhad, M ; Kokabi, A. H ; Sharif University of Technology
    In this study, we attempt to characterize the microstructural evolution during friction stir butt welding of Al-Cu-laminated composites and its effect on the fracture behavior of the joint. Emphasis is on the material flow and particle distribution in the stir zone. For this purpose, optical microscopy and scanning electron microscopy (SEM) images, energy-dispersive spectroscopy EDS and XRD analyses, hardness measurements, and tensile tests are carried out on the joints. It is shown that intermetallic compounds exist in lamellas of banding structure formed in the advancing side of the welds. In samples welded from the Cu side, the banding structure in the advancing side and the hook... 

    The Pt/Ni modified TiO 2 nanotubes and its catalytic activity toward glucose

    , Article ECS Transactions, 1 May 2011 through 6 May 2011 ; Volume 35, Issue 35 , May , 2011 , Pages 63-69 ; 19385862 (ISSN) ; 9781607682950 (ISBN) Mahshid, S. S ; Mahshid, S ; Ghahremaninezhad, A ; Dolati, A ; Ghorbani, M ; Luo, S ; Yang, L ; Cai, Q ; Sharif University of Technology
    The catalytic activity of Pt/Ni/TiO 2 nanotubes electrode toward glucose has been studied. Fabrication of Pt/Ni nanostructures was done in a single-bath solution through electrochemical pulse method by changing the deposition potential between -0.3 and -4 V vs. SCE, respectively. The resulting modified electrode represented high conductivity due to the effective presence of metallic components and uniform surface area caused by dispersion of Pt and Ni nanostructures. The scanning electron microscopy images also confirmed that a large amount of metals colonies were well-dispersed at the edge of the TiO 2 nanotubes. In addition, the Pt/Ni TiO 2 nanotubes modified electrode exhibited an... 

    Effect of RGO/Zn:XCd1- xS crystalline phase on solar photoactivation processes

    , Article RSC Advances ; Volume 6, Issue 52 , 2016 , Pages 46282-46290 ; 20462069 (ISSN) Moradlou, O ; Tedadi, N ; Banazadeh, A ; Naseri, N ; Sharif University of Technology
    Royal Society of Chemistry  2016
    A series of reduced graphene oxide/ZnxCd1-xS (RGO/ZnxCd1-xS) nanocomposites (0 < x < 1) with different ratios of Zn/Cd were synthesized via a facile hydrothermal route under optimized experimental conditions and were carefully characterized by various techniques. Because very little is known about the morphology, specific surface area, and crystal phase effects of RGO/ZnxCd1-xS crystals on their photoresponsivity, field-emission scanning electron microscopy (FE-SEM), BET surface area analysis and X-ray diffraction (XRD) data were studied to investigate their effects on photoactivity. Based on the results, a crystal phase transition from a cubic phase in RGO/Zn0.9Cd0.1S to a hexagonal... 

    Water retention and volumetric characteristics of intact and re-compacted loess

    , Article Canadian Geotechnical Journal ; Volume 53, Issue 8 , 2016 , Pages 1258-1269 ; 00083674 (ISSN) Wang Wai Ng, C ; Sadeghi, H ; Belal Hossen, S. K ; Chiu, C. F ; Alonso, E. E ; Baghbanrezvan, S ; Sharif University of Technology
    Canadian Science Publishing  2016
    Alaboratory testing program was conducted to investigate the effects of microstructure on the water retention curve (WRC) and wetting-drying induced volume change in loess. The axis translation and vapor equilibrium techniques were adopted to control suction in the range of 0-400 kPa and 4-140 MPa, respectively. Hysteresis in the WRC of loess was observed for the entire range of suction studied. Compared to re-compacted loess, intact loess exhibits a more pronounced hysteresis in the suction range below 20 kPa, which can be explained by the ink-bottle pore neck effect or constricted pores. The hypothesis is supported by microstructural evidence of mercury intrusion porosimetry and scanning... 

    Improvements in permeation and fouling resistance of PVC ultrafiltration membranes via addition of Tetronic-1107 and Triton X-100 as two non-ionic and hydrophilic surfactants

    , Article Water Science and Technology ; Volume 74, Issue 6 , 2016 , Pages 1469-1483 ; 02731223 (ISSN) Rabiee, H ; Seyedi, S. M ; Rabiei, H ; Alvandifar, N ; Sharif University of Technology
    IWA Publishing 
    Two non-ionic and hydrophilic surfactant additives, Tetronic-1107 and Triton X-100, were added to poly(vinyl chloride)/NMP polymeric solution to prepare ultrafiltration membranes via immersion precipitation. Surfactants at three different weight percentages up to 6 wt% were added, and the fabricated membranes were characterized and their performance for water treatment in the presence of bovine serum albumin (BSA) as a foulant was assessed. The scanning electron microscopy images indicated remarkable changes in morphology due to higher thermodynamic instability after surfactant addition. The membranes are more porous with more macro-voids in the sub-layer. Plus, the membranes become more... 

    Preparation of metal–organic frameworks UiO-66 for adsorptive removal of methotrexate from aqueous solution

    , Article Journal of Inorganic and Organometallic Polymers and Materials ; 2017 , Pages 1-10 ; 15741443 (ISSN) Aghajanzadeh, M ; Zamani, M ; Molavi, H ; Khieri Manjili, H ; Danafar, H ; Shojaei, A ; Sharif University of Technology
    A low cytotoxic metal–organic framework (MOF) UiO-66 (UiO stands for University of Oslo) and NH2-UiO-66, that showed high cell viability of HFF-2 via 3-(4, 5-dimethylthiazol-2-yl) 2, 5-diphenyl tetrazolium assay, was reported as an effective adsorbent (antidotal) agents. The structure of MOFs was confirmed by Fourier transform infrared, Field emission scanning electron microscopy (FESEM) and X-ray diffraction. Thermal behavior of MOFs was investigated using with thermogravimetric analyzer in nitrogen atmosphere to check the thermal stability. FESEM showed NH2-UiO-66 displayed symmetrical crystals with triangular base pyramid morphology, with the particle size around 100 nm and uniform size... 

    Electrodeposition of well-defined gold nanowires with uniform ends for developing 3D nanoelectrode ensembles with enhanced sensitivity

    , Article Materials Chemistry and Physics ; Volume 213 , 2018 , Pages 67-75 ; 02540584 (ISSN) Bahari Mollamahale, Y ; Ghorbani, M ; Dolati, A ; Hosseini, D ; Sharif University of Technology
    Elsevier Ltd  2018
    Fabrication of well-defined gold nanowires (GNWs) is of significant importance in many fields such as sensing applications. In this study, the electrodeposition of well-defined GNWs inside polycarbonate (PC) template has been discussed in detail. GNWs were potentiostatically electrodeposited at different filling rates. The growth of GNWs at different stages of pore filling was monitored by electrochemical measurements and field-emission scanning electron microscopy (FE-SEM). It was confirmed that under growth rates between 2.5 and 4 nm/s, GNWs with smooth ends grew uniformly inside the template without any imperfections or corrugations. The length of GNWs was electrochemically controlled to... 

    Preparation of metal–organic frameworks uio-66 for adsorptive removal of methotrexate from aqueous solution

    , Article Journal of Inorganic and Organometallic Polymers and Materials ; Volume 28, Issue 1 , 2018 , Pages 177-186 ; 15741443 (ISSN) Aghajanzadeh, M ; Zamani, M ; Molavi, H ; Khieri Manjili, H ; Danafar, H ; Shojaei, A ; Sharif University of Technology
    Springer New York LLC  2018
    A low cytotoxic metal–organic framework (MOF) UiO-66 (UiO stands for University of Oslo) and NH2-UiO-66, that showed high cell viability of HFF-2 via 3-(4, 5-dimethylthiazol-2-yl) 2, 5-diphenyl tetrazolium assay, was reported as an effective adsorbent (antidotal) agents. The structure of MOFs was confirmed by Fourier transform infrared, Field emission scanning electron microscopy (FESEM) and X-ray diffraction. Thermal behavior of MOFs was investigated using with thermogravimetric analyzer in nitrogen atmosphere to check the thermal stability. FESEM showed NH2-UiO-66 displayed symmetrical crystals with triangular base pyramid morphology, with the particle size around 100 nm and uniform size... 

    Sintering of zirconia/430l stainless steel bilayers for co-powder injection moulding

    , Article European International Powder Metallurgy Congress and Exhibition, Euro PM 2008, Mannheim, 29 September 2008 through 1 October 2008 ; Volume 2 , January , 2008 , Pages 299-303 ; 9781899072033 (ISBN) Dourandish, M ; Simchi, A ; Hartwig, T ; Sharif University of Technology
    European Powder Metallurgy Association (EPMA)  2008
    To fabricate ceramic/metal complex-shaped part by co-powder injection moulding process (2KPIM), it is essential to tailor the sintering parameters in order to gain a low mismatch shrinkage, i.e. high sintering compatibility. In the present work, nanocrystalline 3Y-TZP and commercial 430L MIM grade stainless steel powders were co-sintered at various sintering cycles. Isothermal and non-isothermal sintering behavior of the individual and composite layers in argon and vacuum atmospheres were examined. High resolution scanning electron microscopy (HRSEM) coupled with energy dispersive X-ray (EDX) analysis was used to study the bonding interface between the ceramic and metal joints. It is shown... 

    Effects of the preparation conditions on ethylene/vinyl acetate membrane morphology with the use of scanning electron microscopy

    , Article Journal of Applied Polymer Science ; Volume 105, Issue 5 , 2007 , Pages 2683-2688 ; 00218995 (ISSN) Sadeghi, M ; Mousavi, S. A ; Motamed Hashemi, M. Y ; Pourafshari Chenar, M ; Roosta Azad, R ; Sharif University of Technology
    In this research, the effects of preparation conditions, including the coagulation bath temperature, polymer solution composition, preliminary drying time, and thickness of cast polymeric films, on the morphology of ethylene/vinyl acetate copolymer membranes were investigated with scanning electron microscopy and nitrogen gas permeability tests. Flat sheet membranes were prepared through a thermal-wet phase-inversion method. Scanning electron microscopy pictures showed asymmetric structures for some of the membranes. It was also observed that the porosity of the membranes decreased with an increase in the temperature of the coagulation bath and the solvent evaporation period. When the...