Search for: metal
Total 1621 records
Bond strength and formability of an aluminum-clad steel sheet, Article Journal of Alloys and Compounds ; Volume 361, Issue 1-2 , 2003 , Pages 138-143 ; 09258388 (ISSN) ; Karimi Taheri, A ; Sharif University of Technology
The production of an aluminum-clad steel sheet by the cold rolling process is a more efficient and economical approach compared with the other types of processes utilized for the production of such sheets. In this process, high plastic deformation of two metals, aluminum and steel, is necessary to create the cold bonding between the intermediate surfaces. Therefore, the work-hardened sheet must be annealed in order to obtain a high formability. Heat treatment of the sheet is, however, difficult due to the formation of a brittle intermetallic compound of aluminum and iron at the interface between the layers during heat treatment. In this investigation, the formability of these sheets was...
Easy-to-Design Nano-Coupler Between Metal-Insulator-Metal Plasmonic and Dielectric Slab Waveguides, Article Plasmonics ; Volume 8, Issue 2 , 2013 , Pages 1123-1128 ; 15571955 (ISSN) ; Rezaei, M ; Miri, M ; Bahadori, M ; Eshaghian, A ; Mehrany, K ; Sharif University of Technology
An easy-to-design single-stub nano-coupler is proposed to increase the direct coupling efficiency between metal-insulator-metal (MIM) plasmonic and high-index dielectric waveguides. The modal reflection and transmission from the junction are exploited to provide a circuit description for the structure. The return loss of direct coupling is then minimized by loading the MIM waveguide with a single stub. Numerical examples are given, and the accuracy of the model is examined via finite-difference time-domain method
An Efficient Circuit Model for the Analysis and Design of Rectangular Plasmonic Resonators, Article Plasmonics ; Volume 7, Issue 2 , June , 2012 , Pages 245-252 ; 15571955 (ISSN) ; Miri, M ; Khavasi, A ; Mehrany, K ; Rashidian, B ; Sharif University of Technology
An efficient circuit model is proposed for studying the electromagnetic characteristics of rectangular plasmonic cavities. The proposed model comprised a finite size transmission line terminated by scalar load impedances at its both ends. It is capable of the fast extraction of resonance frequencies, quality factors, and mode profiles of plasmonic resonators made by carving rectangles in metallic medium. The accuracy of the proposed model is assessed using the fully numerical finite difference time domain technique. It is employed for analysis and design purposes
Object surface characteristics monitoring using light reflection measurements, Article Journal of Applied Sciences ; Volume 11, Issue 15 , July , 2011 , Pages 2823-2829 ; 18125654 (ISSN) ; Golnabi, H ; Sharif University of Technology
Design and operation of a light reflection system for surface profiling is reported in this article. This system consists of a double-fiber optical probe and a mechanical scanning system. In this arrangement one fiber transmits the source light to the object surface and the second one transmits the light reflected off the surface to a photodetector. By scanning the double-fiber probe assembly in one direction the reflection properties of different plane surfaces are investigated. The reported system can be used to monitor the surface profile of target surfaces made from metallic and non-metallic materials. Obtained results show that the reported method can be utilized to obtain structural...
Dft study of bond energies and attachment sites of sample divalent cations (mg2+, ca2+, zn2+) to histidine in the gas phase, Article Journal of Theoretical and Computational Chemistry ; Volume 8, Issue 3 , 2009 , Pages 347-371 ; 02196336 (ISSN) ; Fattahi, A ; Sharif University of Technology
In view of better understanding interactions of amino acids and peptides with metallic cations in the isolated state, the model system histidineM 2+ (M2+ = Mg2+, Ca2+, Zn 2+) has been studied theoretically. The computations have been performed with the help of the density functional theory (DFT) and the B3LYP functional. The extended basis set was the standard 6-311++G**. All the molecular complexes obtained by the interaction between several energetically low-lying tautomers/conformers/zwitterions of histidine and the cations on different binding sites were considered. Our study shows that complexes of histidine with Mg2+, Ca2+, Zn2+ are rather similar. In the isolated state, the most...
Tensile behaviour and ductility of 10 vol.-% Saffil short fibre reinforced aluminium, Article Materials Science and Technology ; Volume 20, Issue 12 , 2004 , Pages 1645-1648 ; 02670836 (ISSN) ; Nategh, S ; Weber, L ; Sharif University of Technology
The tensile behaviour of Saffil short fibre reinforced aluminium composites has been investigated in terms of Young's modulus, yield strength, ultimate tensile strength, and strain to failure. A rationale is given for the unusually high strain to failure found in this material by applying a failure criterion based on damage accumulation, recently developed for particulate reinforced MMCs
Corrosion and time dependent passivation of Al 5052 in the presence of H2O2, Article Metals and Materials International ; Volume 22, Issue 4 , 2016 , Pages 609-620 ; 15989623 (ISSN) ; Bagheri Hariri, M ; Sharifi Asl, S ; Yaghoubinezhad, Y ; Mortazavi, G ; Seo, Y ; Sharif University of Technology
Korean Institute of Metals and Materials 2016
Corrosion and time–dependent oxide film growth on AA5052 Aluminum alloy in 0.25M Na2SO4 solution containing H2O2 was studied using electrochemical impedance spectroscopy, potentiodynamic polarization, chronoamperometric and open circuit potential monitoring. It was found that sequential addition of H2O2 provokes passivation of AA5052 which ultimately thickens the oxide film and brings slower corrosion rates for AA5052. H2O2 facilitates kinetics of oxide film growth on AA 5052 at 25° and 60 °C which is indicative of formation of a thick barrier film that leads to an increment in the charge transfer resistance. Pitting incubation time increases by introduction of H2O2 accompanied by lower...
Asymmetrical Schiff bases as inhibitors of mild steel corrosion in sulphuric acid media, Article Materials Chemistry and Physics ; Volume 78, Issue 3 , 2003 , Pages 800-808 ; 02540584 (ISSN) ; Mertens, S. F. L ; Ghorbani, M ; Arshadi, M. R ; Sharif University of Technology
Two newly synthesised Schiff bases [H2A3, N,N′-ortho-phenylene(salicylaldimine-acetylacetone imine) and H2A4, N,N′-ortho-phenylene(salicylaldimine-2-hydroxy-1-naphthaldimine)] were studied as inhibitors for the corrosion of mild steel in 0.5 mol dm-3 sulphuric acid. Results of weight loss, electrochemical impedance and Tafel polarisation measurements consistently identify both compounds as good inhibitors, with efficiencies of around 95% at a concentration of 400 ppm. The inhibition is in both cases of a mixed anodic-cathodic nature. Differences in inhibition efficiency between H2A3 and H2A4 are correlated with their chemical structures. Several adsorption isotherms are assessed, and the...
An investigation on the effect of carbon and silicon on flow behavior of steel, Article Materials and Design ; Volume 23, Issue 3 , 2002 , Pages 271-276 ; 02641275 (ISSN) ; Karimi Taheri, A ; Sharif University of Technology
Elsevier Ltd 2002
The effect of carbon and silicon on the occurence of dynamic recrystallization as well as on the flow stress of steel was investigated. For this purpose, three grades of steels including low carbon, medium carbon and high silicon low carbon steel were examined. Single hit experiments at temperatures of 900-1200 °C and strain rate of 0.01-2 s-1 were performed to determine the phase transformation kinetics. Different socking times were utilized to detect the effect of initial austenite grain size on the kinetics of dynamic recrystallization and flow behavior of the steels. It was found that increasing the carbon content leads to a higher rate of dynamic recrystallization at high temperatures...
Synthesis of M/CuO (M = Ag, Au) from Cu based metal organic frameworks for efficient catalytic reduction of p-nitrophenol, Article Materials Chemistry and Physics ; Volume 198 , 2017 , Pages 374-379 ; 02540584 (ISSN) ; Falamarzi, M ; Gholami, M. R ; Sharif University of Technology
Metal Organic Frameworks (MOFs) have received enormous attention in catalysis field due to their special structures and various promising applications. One of the intriguing applications of MOFs is utilization of them as precursors for synthesis of metal oxide nanomaterials. Base on this strategy, in this work, we have applied Cu-MOF to prepare a series of noble metal nanoparticles (Ag and Au) decorated CuO (M/CuO) as efficient catalyst. As-prepared nanocomposites were characterized by various analytical techniques and their catalytic performances appraised by using of the catalytic reduction of p-nitrophenol to p-aminophenol as a reliable model reaction. Experimental results suggest that...
Molecular dynamics study of success evaluation for metallic nanoparticles manipulation on gold substrate, Article Proceedings of the ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference 2009, DETC2009, 30 August 2009 through 2 September 2009 ; Volume 6 , August–September , 2010 , Pages 345-346 ; 9780791849033 (ISBN) ; Meghdari, A ; Jalili, N ; Sharif University of Technology
Using molecular dynamics, the behavior of nanoparticles during manipulation process is investigated in this paper. The system consists of a tip, cluster and substrate. The focus of the present research is on ultra-fine metallic nanoclusters. The system of concern is made of different transition metals. Two criteria have been proposed for evaluation of success in a pushing process. Such criteria describe the intactness of nanoparticle/substrate pair. The effects of cluster material and manipulation speed on the success of the process are investigated by atomistic simulations. Such qualitative simulation studies can evaluate the level of success of manipulation regarding different working...
Manufacturing of multi-functional micro parts by two-component metal injection moulding, Article International Journal of Advanced Manufacturing Technology ; Volume 33, Issue 1-2 , 2007 , Pages 176-186 ; 02683768 (ISSN) ; Rota, A ; Petzoldt, F ; Simchi, A ; Sharif University of Technology
Several metals and alloys can be used to enhance the mechanical and physical properties of micro parts and components for micromechanical, micro-chemical or sensor applications. Such parts can be produced in series by the powder metallurgical process of micro metal injection moulding (μ-MIM). This paper describes a novel manufacturing route for metallic multi-material micro components, two-component micro metal injection moulding (2C-μ-MIM). Similar to "two-colour" injection moulding of plastics, the process allows the integration of multiple functions in a micro part by simultaneously injecting and joining two materials in one mould. Net-shape parts with solid material interfaces are...
DMLS gets an expert once-over, Article Metal Powder Report ; Volume 61, Issue 4 , 2006 , Pages 10-13 ; 00260657 (ISSN) ; Pohl, H ; Simchi, A ; Alcantara, B ; Sharif University of Technology
Elsevier Ltd 2006
Direct Metal Laser Sintering has real potential for rapid-manufacture applications in the PM arena, reducing lead times and cutting costs. But it has been hampered by the limited range of suitable powders available and their cost. A research group led by Fraunhofer scientists made their own powders and took a closer look.... © 2006 Elsevier Ltd. All rights reserved
Investigation of reinforced sic particles percentage on machining force of metal matrix composite, Article Modern Applied Science ; Volume 6, Issue 8 , 2012 , Pages 9-20 ; 19131844 (ISSN) ; Zoghipour, P ; Tarighi, J ; Yousefi, R ; Sharif University of Technology
In this study two-dimensional finite element models of Al/SiC metal matrix composites (MMC) by using of ABAQUS Explicit software are investigated. Chip formations and machining forces for three types of MMC with 5, 15 and 20% of SiC reinforcement particles were studied and compared with experimental data. The resulted chips in simulation and the generated chips in experiments have both continuous and saw tooth in appearance. On the other hand, the variation of the cutting forces with the cutting time in simulation and experiment have fluctuating diagram. This is due to the interaction between cutting tool and SiC particles during chip formation. ABAQUS explicit software was used for...
Semisolid structure for M2 high speed steel prepared by cooling slope, Article Journal of Materials Processing Technology ; Volume 210, Issue 12 , September , 2010 , Pages 1632-1635 ; 09240136 (ISSN) ; Aashuri, H ; Sharif University of Technology
Effects of cooling slope angle and the temperature of molten metal on the globular structure of M2 high speed steel after holding at the semisolid state have been investigated. The globular structure was achieved by pouring the molten metal at 1595 °C on the ceramic cooling slope with the length of 200 mm and the angle of 25°. The globular structure of M2 high speed steel in the form of rolled-annealed and as cast condition after holding at semisolid state has been achieved. The size of globular grains of cooling slope sample was smaller than that of the rolled-annealed and as cast samples. Solid particles of rolled-annealed sample after holding at semisolid state had better roundness...
Noble metal nanoparticles in biosensors: Recent studies and applications, Article Nanotechnology Reviews ; Volume 6, Issue 3 , 2017 , Pages 301-329 ; 21919089 (ISSN) ; Sahandi Zangabad, P ; Mirshekari, H ; Karimi, M ; Hamblin, M. R ; Sharif University of Technology
Walter de Gruyter GmbH 2017
The aim of this review is to cover advances in noble metal nanoparticle (MNP)-based biosensors and to outline the principles and main functions of MNPs in different classes of biosensors according to the transduction methods employed. The important biorecognition elements are enzymes, antibodies, aptamers, DNA sequences, and whole cells. The main readouts are electrochemical (amperometric and voltametric), optical (surface plasmon resonance, colorimetric, chemiluminescence, photoelectrochemical, etc.) and piezoelectric. MNPs have received attention for applications in biosensing due to their fascinating properties. These properties include a large surface area that enhances biorecognizers...
Dft study on gas-phase interaction between histidine and alkali metal ions (li+, na+, k+); and influence of these ions on histidine acidity, Article Journal of Theoretical and Computational Chemistry ; Volume 8, Issue 3 , 2009 , Pages 475-490 ; 02196336 (ISSN) ; Fattahi, A. R ; Sharif University of Technology
The gas-phase metal affinities of histidine Li+, Na+ and K+ ions have been determined theoretically employing the hybrid B3LYP exchangecorrelation functional and using 6-311++G** basis sets. All computations indicate that the metal ion affinity decreases on going from Li+ to Na+ and K+ for the considered amino acid. Different types of M+ coordinations on several histidine conformers/tautomers were considered in detail. The optimized structures indicate that Li+ and Na+ prefer a tri-dentate coordination, bonding with a nitrogen atom of imidazole ring (N τ), NH2, and an oxygen atom of a carbonyl, while in the K+-histidine lowest-energy conformer, the cation appears to be bi-coordinated to both...
Fabrication of a highly flexible and affordable transparent electrode by aligned u-shaped copper nanowires using a new electrospinning collector with convenient transferability, Article ACS Omega ; Volume 4, Issue 25 , 2019 , Pages 21260-21266 ; 24701343 (ISSN) ; Mohamadbeigi, N ; Sadrnezhaad, Kh ; Mahdavi, M ; Sharif University of Technology
American Chemical Society 2019
By making aligned and suspended copper nanowires, a high performance, transferable, and flexible transparent electrode is reported. Indium tin oxide is often used in devices such as displays, solar cells, and touchscreens that require transparent and conductive plates. Because of problems such as brittleness, high cost, and environmental effects, this material is facing rivals, the most serious of which are metallic nanowire meshes, especially copper. We developed a simple technique which uses a U-shaped collector in the electrospinning process with three advantages including the enhancement of the figure of merit (which is related to the surface resistance Rs and the transmittance T) by...
Modeling of liquid-gas flow through Porous media: application in metal recovery, Article CHISA 2006 - 17th International Congress of Chemical and Process Engineering, Prague, 27 August 2006 through 31 August 2006 ; 2006 ; 8086059456 (ISBN); 9788086059457 (ISBN) ; Yaghmaei, S ; Jafari, A ; Zamankhan, P ; Sharif University of Technology
Modeling of air venting in pressure die casting process, Article Journal of Manufacturing Science and Engineering ; Volume 126, Issue 3 , 2004 , Pages 577-581 ; 10871357 (ISSN) ; Goldak, J. A ; Sharif University of Technology
American Society of Mechanical Engineers(ASME) 2004
In this study an analytical model has been developed to describe air pressure and residual air mass variations in pressure die casting for atmospheric venting. During injection of molten metal into a die cavity, air is evacuated from the cavity through vents. In this study, the influences of air velocity and friction factor due to temperature dependent viscosity and vent roughness change have been investigated. The results of the model show that there is a critical area ratio over which a quasi steady state is reached, therefore, the air pressure in the cavity remains constant. In addition, for each area ratio there is a critical/ minimum time ratio below which outlet Mach number is not...