Search for: chemical-composition
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    Predictions of toughness and hardness by using chemical composition and tensile properties in microalloyed line pipe steels

    , Article Neural Computing and Applications ; 2014 Faizabadi, M. J ; Khalaj, G ; Pouraliakbar, H ; Jandaghi, M. R ; Sharif University of Technology
    Artificial neural networks with multilayer feed forward topology and back propagation algorithm containing two hidden layers are implemented to predict the effect of chemical composition and tensile properties on the both impact toughness and hardness of microalloyed API X70 line pipe steels. The chemical compositions in the forms of "carbon equivalent based on the International Institute of Welding equation (CEIIW)", "carbon equivalent based on the Ito-Bessyo equation (CEPcm)", "the sum of niobium, vanadium and titanium concentrations (VTiNb)", "the sum of niobium and vanadium concentrations (NbV)" and "the sum of chromium, molybdenum, nickel and copper concentrations (CrMoNiCu)", as well... 

    Effect of cold rolling reduction and intercritical annealing temperature on the bulk texture of two TRIP-aided steel sheets

    , Article Journal of Materials Processing Technology ; Volume 203, Issue 1-3 , 2008 , Pages 293-300 ; 09240136 (ISSN) Emadoddin, E ; Akbarzadeh, A ; Daneshi, Gh ; Sharif University of Technology
    High strength TRIP-aided steel sheets with high formability and better ductility are of industrial interest. Texture control and retained austenite characterization are considered as the main factors with respect to the formability and ductility. Processing parameter such as initial conditions of hot rolling, cold rolling to final size of sheet, intercritical annealing after cold rolling and subsequent isothermal heat treatment to achieve TRIP specification in product, affect bulk texture of sheets. Moreover, chemical composition of steel should be noted especially because it can change the intensity of orientation and final macro texture of sheet. In this work, the effect of cold rolling... 

    Effect of annealing on soft magnetic behavior of nanostructured (Fe 0.5Co0.5)73.5Si13.5B 9Nb3Cu1 ribbons

    , Article Journal of Alloys and Compounds ; Vol. 582, issue , 2014 , pp. 79-82 Gheiratmand,T ; Hosseini, H. R. M ; Davami, P ; Gjoka, M ; Loizos, G ; Aashuri, H ; Sharif University of Technology
    The effects of relaxation and nanocrystallization on magnetic properties of (Fe0.5Co0.5)73.5Si13.5B 9Nb3Cu1 ribbons have been investigated. Ribbons were melt-spun at wheel speed of 38 m/s and then annealed at different temperatures. The results indicated that the relaxation processes shift the Curie temperature of amorphous phase to the higher temperatures. It was also found that through crystallization phenomena the saturation magnetization increases due to the super-exchange between Fe and Co atoms in the crystalline phase. A slight variation in magnetization was observed at ~700 °lC during heating due to the ordering transition in FeCo system. At early stage of crystalline phase... 

    Application of artificial neural networks to prediction of chemical composition of electrodeposited Ni-Mo thin films

    , Article ECS Transactions ; Volume 50, Issue 52 , Oct , 2012 , Pages 63-71 ; 19385862 (ISSN) Allahyarzadeh, M. H ; Rouhaghdam, A. S ; Aliofkhazraie, M ; Shahrabi, T ; Ashrafi, A ; Seddighian, A ; Sharif University of Technology
    Present research represents the application of artificial neural networks to predict the chemical composition of electrodeposited Ni-Mo thin films. Artificial neural networks commonly are utilized as a prediction tools so that these networks could approximately find kind of logic relationships between inputs and target; they fitted appropriate coefficient and weighting factors to the inputs which are proportional to their importance. In order to evaluate the model developed, experimental results were compared with the predicted ones. However, more data are required to train more reliable prediction models, presents study revealed an acceptable error less than 1% between predicted values and... 

    Practical properties and formaldehyde emission of medium density fiberboards (MDFs) recycled by electrical method

    , Article European Journal of Wood and Wood Products ; Volume 76, Issue 4 , 2018 , Pages 1287-1294 ; 00183768 (ISSN) Moezzipour, B ; Abdolkhani, A ; Doost hoseini, K ; Ramazani Saadat Abadi , A ; Tarmian, A ; Sharif University of Technology
    Springer Verlag  2018
    In this study, the performance of the electrical method in MDF wastes recycling was determined. For investigating the practical aspect of the electrical method, the hydrothermal method as a known recycling method was studied too. The recycling process by electrical method conducted for two different time durations (2 and 4 min) at a temperature of 100 °C and recycling using the hydrothermal method was done at a temperature of 105 °C for 150 min under 4 bar pressure with subsequent refining step. Recycled fibers were analyzed by determination of the chemical composition of fibers and fiber classification. After that, laboratory MDF boards with dimensions of 35 × 35 × 12 mm3 and density of... 

    Discovery of novel quaternary bulk metallic glasses using a developed correlation-based neural network approach

    , Article Computational Materials Science ; Volume 186 , 2021 ; 09270256 (ISSN) Samavatian, M ; Gholamipour, R ; Samavatian, V ; Sharif University of Technology
    Elsevier B.V  2021
    The immense space of composition-processing parameters leads to numerous trial-and-error experimental works for engineering of novel bulk metallic glasses (BMGs). To tackle this challenging problem, it is required to consider specific guidelines which are able to restrict the productive alloying compositions. In this work, a correlation-based neural network (CBNN) approach was developed, based on a dataset of 7950 alloying compositions, to design potential new MGs through prediction of casting ability, reduced glass transition (Trg) and critical thickness (Dmax). This approach involves individual and mutual characteristics of contributory factors to improve the prediction accuracy. To... 

    Adjustment of materials and sintering processes for MIM of Bi-material parts

    , Article European Powder Metallurgy Congress and Exhibition, Euro PM 2005, Prague, 2 October 2005 through 5 October 2005 ; Volume 2 , 2005 , Pages 315-320 ; 9781899072187 (ISBN) Imgrund, P ; Rota, A ; Hartwig, T ; Petzoldt, F ; Simchi, A ; European Powder Metallurgy Association ; Sharif University of Technology
    European Powder Metallurgy Association (EPMA)  2005
    In this paper, an investigation of bi-material parts produced by a two-component metal injection moulding process is presented. The compatibility of different materials for this process was evaluated by sinter dilatometry, taking into account the effects of powder particle size, powder loading and use of master alloys on the sintering behaviour. In a second step, sample material joints of 316L / H13, 316L / 17-4PH and 316L / iron were moulded, debinded and sintered together. The interfaces obtained were examined by optical microscopy and SEM. The diffusion of alloying elements across the interfaces was shown as a function of sintering temperatures. Changes in microstructures and chemical... 

    Characterization of pulse reverse Ni-Mo coatings on Cu substrate

    , Article Surface and Coatings Technology ; Vol. 238 , 2014 , pp. 158-164 ; ISSN: 02578972 Surani Yancheshmeh, H ; Ghorbani, M ; Sharif University of Technology
    The effect of pulse reverse current (PRC) method on Ni-Mo coatings electroplated from chloride solution was investigated by various plating parameters such as plating duration, the anodic duty cycle, the anodic current density and the cathodic current density. By increasing the anodic duty cycle and anodic current density, the Mo content of coatings reached 68wt.% and 78wt.%, respectively at cathodic current densities of 500 and 300mAcm-2. The Mo content of coatings increases by the preferential dissolution of Ni on the anodic pulse and also by the replenishment of Mo complexes in the diffusion layer near the substrate surface during the anodic pulse. In comparison with the direct current... 

    Infrared thin layer drying of saffron (Crocus sativus L.) stigmas: Mass transfer parameters and quality assessment

    , Article Chinese Journal of Chemical Engineering ; Volume 25, Issue 4 , 2017 , Pages 426-432 ; 10049541 (ISSN) Torki Harchegani, M ; Ghanbarian, D ; Maghsoodi, V ; Moheb, A ; Sharif University of Technology
    Chemical Industry Press  2017
    Saffron is the most precious and expensive agricultural product. A dehydration treatment is necessary to convert Crocus sativus L. stigmas into saffron spice. To the best of our knowledge, no information on mass transfer parameters of saffron stigmas is available in the literature. This study aimed at investigating the moisture transfer parameters and quality attributes of saffron stigmas under infrared treatment at different temperatures (60, 70, …, 110 °C). It was observed that the dehydration process of the samples occurred in a short accelerating rate period at the start followed by a falling rate period. The effective moisture diffusivity and convective mass transfer coefficient were... 

    Structure and corrosion behavior of oxide layer with Zr compounds on AZ31 Mg alloy processed by two-step plasma electrolytic oxidation

    , Article Surface and Coatings Technology ; Vol. 238 , 2014 , pp. 75-79 ; ISSN: 02578972 Einkhah, F ; Lee, K. M ; Sani, M. A. F ; Yoo, B ; Shin, D. H ; Sharif University of Technology
    The formation of the oxide layer with Zr compounds on AZ31 Mg alloy processed by two-step plasma electrolytic oxidation (PEO) has been investigated. After the PEO process first in an alkaline phosphate electrolyte and second in an acid electrolyte containing K2ZrF6, the microstructure, chemical composition, and phase composition of the oxide layers were analyzed via SEM, EDS, and XRD, respectively. The electrochemical reaction and the high temperature caused by the plasma discharges in the electrolyte were the main factors leading to the fabrication of an oxide layer containing Zr compounds on AZ31 Mg alloy. The micro-pores were filled with ZrO2 formed during the PEO process. The results of... 

    Pt and Pd as catalyst deposited by hydrogen reduction of metal salts on WO3 films for gasochromic application

    , Article Applied Surface Science ; Volume 273 , May , 2013 , Pages 261-267 ; 01694332 (ISSN) Tahmasebi Garavand, N ; Mahdavi, S. M ; Iraji Zad, A ; Sharif University of Technology
    In this study, tungsten oxide films were deposited by pulsed-laser deposition (PLD) technique. The as-deposited films were annealed at 250 °C in air for 1 h. The surface morphology, microstructure, crystalline phase, and chemical composition of the films were characterized by SEM, XRD and XPS techniques. Pt nanoparticles were deposited onto the tungsten oxide films through a two-step process. First of all, a layer of PtCl2 was coated on the WO3 surface by drop-drying the PtCl2 solution onto the WO3 surface at 60 °C. Consequently, the reduction of the PtCl2 into the metallic Pt nanoparticles was performed at 200 °C. In this study, the effect of the temperature during hydrogen reduction of... 

    Catalytic effect of copper oxide on H2S sensing properties of nanostructured WO3

    , Article Sensor Letters ; Volume 11, Issue 11 , 2013 , Pages 2015-2020 ; 1546198X (ISSN) Nowrouzi, R ; Razi, F ; Rahimi, F ; Zad, A. I ; Sharif University of Technology
    American Scientific Publishers  2013
    Cuprous oxide powder was added to WO3 sol as a catalyst and the composite sol was deposited on alumina substrates by spin coating process and annealing at 500 °C for 1 hour. Sensing properties of the pure and doped tungsten oxide samples to H2S gas were analyzed. WO 3-Cu2O (1%) samples showed good sensitivity towards 250 ppb of the gas at 100 °C and 1 ppm at room temperature (25 °C). Crystal structure, morphology and chemical composition of the sample were studied by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDAX) analyses and X-ray photoelectron spectroscopy (XPS). Based on these data, possible reaction mechanisms of hydrogen sulfide over WO... 

    Transient liquid phase bonding of wrought IN718 nickel based superalloy using standard heat treatment cycles: Microstructure and mechanical properties

    , Article Materials and Design ; Volume 50 , 2013 , Pages 694-701 ; 02641275 (ISSN) Pouranvari, M ; Ekrami, A ; Kokabi, A. H ; Sharif University of Technology
    Elsevier Ltd  2013
    Transient liquid phase (TLP) diffusion bonding is a preferred joining/repairing technique for nickel based superalloy. In this research, TLP bonding process carried out according to the standard heat treatment cycles for wrought IN718 base material in order to permit the combining of these two thermal operations. The results showed that the standard solution treatments at 1000 and 1050. °C for 60. min can result in completion of isothermal solidification in IN718/Ni-Cr-Fe-Si-B/IN718 system producing an entirely intermetallic free joint centerline. Two distinct microstructural zones were formed in the bonding affected zone: isothermal solidification zone (ISZ) which consists of single phase... 

    Effect of lanthanum doping on the lifetime of Co/γ-Al 2O 3 catalysts in Fischer-Tropsch synthesis

    , Article Journal of the Taiwan Institute of Chemical Engineers ; Volume 43, Issue 5 , September , 2012 , Pages 704-710 ; 18761070 (ISSN) Hemmati, M. R ; Kazemeini, M ; Zarkesh, J ; Khorasheh, F ; Sharif University of Technology
    Elsevier  2012
    Cobalt-based catalysts were prepared on gamma alumina supports, and their behaviour for different Fischer-Tropsch synthesis (FTS) conditions was assessed. Although Co/γ-Al 2O 3 is a well-known FTS catalyst, its durability ought to be improved to make the industrial process economically feasible. The effect of lanthanum doping on the catalyst lifetime was examined utilising reactor tests and catalyst characterization techniques including TPR, ICP and N 2 porosimetry. Reactor test results revealed that an optimum amount of lanthanum improved catalyst activity and selectivity. Increasing amounts of lanthanum doping up to about 1.1wt% seemed to modify the chemical composition of the support... 

    Hydrogen sensor based on MWNTs/WO 3

    , Article Proceedings of IEEE Sensors ; 2011 , Pages 5-7 ; 9781424492886 (ISBN) Azam, I. Z ; Roghayeh, G ; IEEE SENSORS Council ; Sharif University of Technology
    In this article we report hydrogen sensing property of WO 3/MWNTs thin films that were fabricated by spin-coating on alumina substrates. The MWNTs were initially functionalized (f-MWNTs) to enhance dispersion in the sol of multiwalled carbon nanotubes (MWNTs) and tungsten trioxide (WO 3). Microstructure, morphology and chemical composition of the materials were characterized by SEM, TEM, XRD and XPS methods. Our results show WO 3 nanoparticles were nucleated on oxygenated group on surface of f-MWNTs in hybrid suspension. After annealing the films at 350 °C, electrical conductance measurements at different operating temperature were performed and the results indicates rather fast and linear... 

    Investigation of the Shaft Failure Connected to Extruder

    , Article Journal of Failure Analysis and Prevention ; Volume 15, Issue 6 , 2015 , Pages 775-781 ; 15477029 (ISSN) Pelaseyed, S. S ; Mashayekhi, F ; Movahedi-Rad, A ; Sharif University of Technology
    Springer New York LLC  2015
    In this study, the failure analysis of a shaft of a unit, which had been failed during the service, was studied. This shaft was welded to the blades, and their chemical compositions were determined by spectroscopy method. In order to determine the root cause of failure and contribution factors, different investigation methods including visual examination, optical microscopy and scanning electron microscope analysis, and hardness test were carried out. It was concluded that the shaft was failed due to fatigue. The failure was caused by improper welding of blades to the shaft. At the end, in order to prevent or decelerate such failure, some recommended remedies were suggested  

    Plasma effects on anti-felting properties of wool fabrics

    , Article Surface and Coatings Technology ; Volume 205, Issue SUPPL. 1 , December , 2010 , Pages S349-S354 ; 02578972 (ISSN) Shahidi, S ; Rashidi, A ; Ghoranneviss, M ; Anvari, A ; Wiener, J ; Sharif University of Technology
    Low temperature plasma (LTP) is nowadays an intensively investigated superficial treatment of wool. In this work we have investigated the effect of LTP on wool fabric under different conditions. The effect of the position of samples inside the reactor and the kind of gases used as discharge medium has been also investigated. The results show that not only the topography of the surface is modified but also the chemical composition of the surface. It is shown that the hydrophilicity of the samples and also their shrink resistance and anti-felting behavior have improved significantly under LTP treatment. The results show that the shrinkage of 30.1% for untreated samples has reduced to about... 

    Surface micromorphology and fractal geometry of Co/CP/X (X = Cu, Ti, SM and Ni) nanoflake electrocatalysts

    , Article RSC Advances ; Volume 6, Issue 32 , 2016 , Pages 27228-27234 ; 20462069 (ISSN) Ţəlu, Ş ; Solaymani, S ; Bramowicz, M ; Naseri, N ; Kulesza, S ; Ghaderi, A ; Sharif University of Technology
    Royal Society of Chemistry  2016
    This paper analyses the three-dimensional (3-D) surface texture of Co/CP/X (X = Cu, Ti, SM and Ni, CP: carbonaceous paste) nanoflakes prepared electrochemically using a conventional three electrode system. The surface chemical composition of the samples was investigated by X-ray photoelectron spectroscopy (XPS). Surface images were recorded using scanning electron microscopy (SEM) and analyzed by means of the fractal geometry. Statistical, fractal and functional surface properties of the prepared samples were computed. The statistical functions applied to the SEM data were employed in order to characterise the surfaces topographically (in amplitude, spatial distribution and pattern of... 

    New insight into H2S sensing mechanism of continuous SnO2-CuO bilayer thin film: A theoretical macroscopic approach

    , Article Journal of Physical Chemistry C ; Volume 120, Issue 14 , 2016 , Pages 7678-7684 ; 19327447 (ISSN) Boroun, Z ; Ghorbani, M ; Moosavi, A ; Mohammadpour, R ; Sharif University of Technology
    American Chemical Society  2016
    SnO2-CuO is one the most promising systems for detection of detrimental H2S gas. Although previous experimental research has suggested a sulfidation reaction to explain selectivity toward H2S, little is known about the origin of change of electrical response of this system by changing the H2S gas concentration. In this study the relation between sensing response of continuous SnO2-CuO bilayer thin film and H2S gas concentration is computed based on changeability of chemical composition of covellite CuxS. For this purpose, chemical activity of sulfur as a function of atomic fraction in covellite copper sulfide is estimated using Gibbs energies of formation and chemical thermodynamics. By... 

    Fabrication and the electrochemical activation of network-like MnO2 nanoflakes as a flexible and large-area supercapacitor electrode

    , Article Journal of Solid State Electrochemistry ; Volume 22, Issue 11 , 2018 , Pages 3507-3514 ; 14328488 (ISSN) Mardi, S ; Moradlou, O ; Moshfegh, A. Z ; Sharif University of Technology
    Porous network-like MnO2 thick films are successfully synthesized on a flexible stainless steel (SS) mesh using a simple and low-cost electrodeposition method followed by an electrochemical activation process. Morphology, chemical composition, and crystal structure of the prepared electrodes before and after the activation process are determined and compared by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) analyses. The results show that the implementation of the electrochemical activation process does not change the chemical composition and crystal structure of the films, but it influences the surface morphology of the MnO2...