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    Synthesis parameters effect on the final morphology of the layered double hydroxide (LDH)

    , Article Protection of Metals and Physical Chemistry of Surfaces ; Volume 53, Issue 3 , 2017 , Pages 460-465 ; 20702051 (ISSN) Imanieh, I ; Afshar, A ; Sharif University of Technology
    Maik Nauka Publishing / Springer SBM  2017
    Abstract
    Smart coatings which prevent corrosion by several mechanisms recently have been carefully planned. One of these mechanisms is the use of ion exchangers like LDH in the coating network. Since the morphology is the most important properties for the applications that the surface plays an important role, LDH morphology was evaluated in this study. For this purpose, the LDH contain a kind of green inhibitor was synthesized and after evaluating its performance it was examined morphologically by changing significant parameters like MII/MIII, pH, aging time and temperature. It is found that, high ratio of the MII/MIII cause thinner layer of LDH. The pH also has special effect on the surface... 

    Effect of rolling speed on the occurrence of strain aging during and after warm rolling of a low-carbon steel

    , Article Journal of Materials Science ; Volume 45, Issue 13 , July , 2010 , Pages 3405-3412 ; 00222461 (ISSN) Koohbor, B ; Ohadi, D ; Serajzadeh, S ; Akhgar, J. M ; Sharif University of Technology
    2010
    Abstract
    In this study, effect of rolling speed on strain aging phenomena in warm rolling of a carbon steel has been investigated. For this purpose, by using a mathematical model and predicting temperature and strain rate fields, the possibility of occurrence of dynamic strain aging during the warm rolling was first evaluated. In the next stage, warm-rolled samples were aged up to 11 months at room temperature for studying the kinetics of static strain aging, while mechanical tests as well as microstructural evolutions have been performed to determine the effect of strain aging on material behavior. The results indicate that dynamic strain aging may not occur for the employed rolling program;... 

    Computational elucidation of the aging time effect on zeolite synthesis selectivity in the presence of water and diquaternary ammonium iodide

    , Article Physical Chemistry Chemical Physics ; Volume 23, Issue 37 , 2021 , Pages 21240-21248 ; 14639076 (ISSN) Ghanbari, B ; Kazemi Zangeneh, F ; Sastre, G ; Moeinian, M ; Marhabaie, S ; Taheri Rizi, Z ; Sharif University of Technology
    Royal Society of Chemistry  2021
    Abstract
    An example of zeolite selectivity (MFI → MOR) driven by synthesis aging time has been studied. Using N,N,N′,N′-tetramethyl-N,N′-dipropyl-ethylenediammonium diiodide (TMDP) as an organic structure-directing agent (OSDA), the zeolite phases obtained at 2 h (MFI 97%), 8 h (MFI 84%, MOR 16%) and 24 h (MFI 43%, MOR 57%) have been characterized by powder X-ray diffraction. The results suggest that at intermediate aging time, namely 8 h and 24 h, the dominant phase (MFI) is displaced by MOR. Different techniques (FT-IR, Raman, 13C MAS NMR, TGA/DTG and HC microanalysis) have been employed to verify the OSDA integrity and occlusion inside the zeolite micropores as well as to quantify the water and... 

    Effect of time and temperature on crude oil aging to do a right surfactant flooding with a new approach

    , Article Proceedings of the Annual Offshore Technology Conference ; Vol. 2, issue , 2014 , p. 1136-1142 ; ISSN: 01603663 ; ISBN: 9781632663870 Heidari, M. A ; Habibi, A ; Ayatollahi, S ; Masihi, M ; Ashoorian, S ; Sharif University of Technology
    Abstract
    Dilute Surfactant flooding has been recognized as one of the significant processes in chemical flooding. Many oil reservoirs became appropriate candidates for surfactant/water flooding when screening criteria was developed. Injected surfactant tried to mobilize the residual oil that was trapped in interstice. The main contributing mechanism to enhance oil recovery by surfactant flooding was defined as rock wettability alteration. Wettability is one of the substantial parameters to choose the best approach for a successful surfactant flooding in which tiny change in wettability will lead to improve oil recovery fundamentally. In this experimental study the effect of different aging time and... 

    Protection of titanium metal by nanohydroxyapatite coating with zirconia and alumina second phases

    , Article Protection of Metals and Physical Chemistry of Surfaces ; Volume 48, Issue 6 , 2012 , Pages 688-691 ; 20702051 (ISSN) Family, R ; Solati Hashjin, M ; Nik, S. N ; Nemati, A ; Sharif Universty of Technology
    2012
    Abstract
    In this study hydroxyapatite (HA)/zirconia/alumina composite coatings on titanium metal was carried out using Sol-Gel dip coating and calcination process. Hydroxyapatite-Alumina-Zirconia sol, coated samples in three processes by changing final sol stirring time, aging time, calcination temperature of synthesized powder and prepared coating and rate of coating. Some parts of prepared sol were also synthesized and became powder in all three processes. Scanning electron microscopy was used to estimate the particle size of the surface and for morphological analysis. The functional group and crystallization characteristics of the powders were analyzed using (FTIR) and X-Ray diffraction (XRD).... 

    Study on static strain aging of 6082 aluminium alloy

    , Article Materials Science and Technology ; Volume 26, Issue 2 , Jul , 2010 , Pages 169-175 ; 02670836 (ISSN) Dadbakhsh, S ; Karimi Taheri, A ; Sharif University of Technology
    2010
    Abstract
    In this study both the quench aging and static strain aging kinetics of a 6082 Al alloy were investigated at a temperature range of 130-200°C using the Vickers hardness and tensile test. The activation energy and dislocation density were determined at different stages of the aging phenomenon. The former was used to analyse the kinetics of aging and the latter to interpret the competition of strengthening and recovery mechanisms during aging. It is shown that different activation energies are achieved depending on the aging time and temperature relating to formation of appropriate precipitates at different stages of aging. Moreover, it is revealed that prestrain reduces the activation energy.... 

    Corrosion protection of aluminum by smart coatings containing layered double hydroxide (LDH) nanocontainers

    , Article Journal of Materials Research and Technology ; Volume 8, Issue 3 , 2019 , Pages 3004-3023 ; 22387854 (ISSN) Imanieh, I ; Afshar, A ; Sharif University of Technology
    Elsevier Editora Ltda  2019
    Abstract
    In this study, the LDH containing a kind of green inhibitor (sodium molybdate) was synthesized and utilized in a poly-vinyl alcohol (PVA) base coating applied on the aluminum (5054 series) surface. After evaluating the LDH performance, the inhibitor release from the LDH crystals was examined by changing significant parameters like MII/MIII (the molar ratio of divalent ions into trivalent ions), pH, aging time and temperature. In order to find the kinetic release of intercalated inhibitor a prediction model was introduced in 3.5% NaCl solution. The model expressed that the pH as the processing parameter has special effect on the kinetic releasing of the inhibitor. It can enhance the amount of...