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Modelling of the effect of operational parameters and concentration of some corrosion inhibitors on the corrosion of carbon steel
, Article Anti-Corrosion Methods and Materials ; Volume 49, Issue 6 , 2002 , Pages 426-432 ; 00035599 (ISSN) ; Kazemeini, M ; Safekordi, A ; Badakhshan, A ; Sharif University of Technology
2002
Abstract
Several corrosion inhibitors, such as, HEDP, sodium molybdate and zinc ions, were added to an aqueous corrosive media containing different concentrations chloride ions, and the corrosion rates (CRs) of carbon steel were measured at various temperatures. It was shown that, in the presence of more than 1,200 ppm of chloride ions, and temperatures greater than or equal to 42.5°C, the combination of HEDP, molybdate and zinc could not control the corrosion in a cooling water system. Then four different models were designed to represent the CR of carbon steel in presence of various corrosive parameters
Expression of PIAS genes in migraine patients
, Article Journal of Molecular Neuroscience ; Volume 71, Issue 10 , 2021 , Pages 2053-2059 ; 08958696 (ISSN) ; Hesami, O ; Nazer, N ; Sayad, A ; Taheri, M ; Sharif University of Technology
Humana Press Inc
2021
Abstract
Migraine is a complex disabling condition which is associated with dysregulation of several pathways particularly those being associated with immune responses. In order to assess contribution of protein inhibitor of activated STAT (PIAS) in the pathogenesis of migraine, we quantified expression levels of PIAS1–PIAS4 genes in the circulation of patients with migraine compared with controls. Expression of PIAS1 was substantially lower in total migraineurs compared with controls (ratio of mean expressions (RME) = 0.18, SE = 0.29, P value < 0.001) and in both male and female migraineurs compared with sex-matched controls. Expression of PIAS2 was lower in migraineurs without aura compared with...
Inhibitory activity on type 2 diabetes and hypertension key-enzymes, and antioxidant capacity of veronica persica phenolic-rich extracts
, Article Cellular and Molecular Biology ; Volume 62, Issue 6 , 2016 , Pages 80-85 ; 01455680 (ISSN) ; Tayeboon, G. S ; Sharifi Rad, J ; Iriti, M ; Varoni, E. M ; Razazi, S ; Sharif University of Technology
Cellular and Molecular Biology Association
2016
Abstract
Veronica genus (Plantaginaceae) is broadly distributed in different habitats. In this study, the inhibitory activity of free soluble and conjugated phenolic extracts of Veronica persica on key enzymes associated to type 2 diabetes (α-glucosidase and α-amylase) and hypertension (angiotensin I converting enzyme, ACE) was assessed, as well as their antioxidant power. Our results showed that both the extracts inhibited α-amylase, α-glucosidase and ACE in a dose-dependent manner. In particular, free phenolic extract significantly (P < 0.05) inhibited α-glucosidase (IC50 532.97 μg/mL), whereas conjugated phenolic extract significantly (P < 0.05) inhibited a-amylase (IC50 489.73 μg/mL) and ACE...
Evaluation of the Effect of Olive Leaf Extract (Olive Leaf) as a Green Inhibitor on Corrosion of Concrete Steel Reinforcements in the Persian Gulf Sea Water Simulator
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdollah (Supervisor)
Abstract
In this project, olive leaf extract has been investigated as a green corrosion inhibitor or in other words environmentally friendly for rebars embedded in concrete in the Persian Gulf Sea water simulator. Olive leaves were prepared by ultrasonic method at 50 ° C with the help of ethanol solvent. The water-ethanol solvent was 70:30 and the resulting extract was immediately applied to the concrete mix in specified doses. Portland cement type 2 according to ISIRI-389-96 standard has been used to prepare concrete. The resulting extract powder was added to the samples in four different doses: 2%, 4%, 6%, 8% by weight of cement to prove the inhibitory function as well as the cathodic or inhibitory...
Use of artificial neural networks in a QSAR study of Anti-HIV activity for a large group of HEPT derivatives
, Article Journal of Chemical Information and Computer Sciences ; Volume 40, Issue 1 , 2000 , Pages 147-154 ; 00952338 (ISSN) ; Parastar, F ; Sharif University of Technology
American Chemical Society
2000
Abstract
Anti-HIV activity for a set of 107 inhibitors of the HIV-1 reverse transcriptase, derivatives of 1-[2-hydroxyethoxy)methyl]-6-(phenylthio)thymine (HEPT), was modeled with the aid of chemometric techniques. The activity of these compounds was estimated by means of multiple linear regression (MLR) and artificial neural network (ANN) techniques and compared with the previous works. The results obtained using the MLR method indicate that the anti-HIV activity of the HEPT derivatives depends on the reverse of standard shadow area on the YZ plane and the ratio of the partial charges of the most positive atom to the most negative atom of the molecule. The best computational neural network model was...
Evaluation of the Performance of Sheng (Tragopogon Buphthalmos Boiss) Extract as a Green Corrosion Inhibitor in High Concentration Hydrochloric Acid Solutions
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdollah (Supervisor)
Abstract
In this study, the extract of Tragopogon buphthalmos Boiss was investigated as a green or environmentally friendly corrosion inhibitor for mild carbon steels in high concentration hydrochloric acid solutions. Tragopogon buphthalmos Boiss was extracted using the extraction method of digestion at 50 ° C assisted by ultrasonic bath. Water-ethanol-acetone solvents were used in ratios of 30:35:35, respectively. The ratio of plant volume to solvent volume was one to ten. The container containing the extract was placed in a bath water at 50 ° C until the extract was in the form of gum, then stored at -15 ° C In a freezer. Infrared Fourier transform spectroscopy (FTIR) was used to determine the...
Experimental and theoretical studies of media effects on copper Corrosion in acidic environments containing 2-amino-5-mercapto-1,3,4-thiadiazole
, Article Journal of the Iranian Chemical Society ; Volume 7, Issue 2 , June , 2010 , Pages 478-486 ; 1735207X (ISSN) ; Arshadi, M.R ; Biglar, M ; Sharif University of Technology
2010
Abstract
Corrosion behaviour of copper metal in acid solutions (HCl, H 2SO4 and H3PO4) containing 2-amino-5-mercapto-1,3,4-thiadiazole (AMT) was investigated experimentally and theoretically via gravimetric, potentio-dynamic and quantum electrochemical approaches. Similar behavior was observed for H2SO4 and H3PO4 media, and related to the nature of anions at metal/solution interface. With regard to HCl, however, the rate of corrosion was determined to be low at initial stages, but high later on using an auto-catalyzing mechanism. In the presence of AMT, the experimental studies revealed that this molecule was a good anodic-type inhibitor causing substantial changes in corrosion potential. Moreover,...
Simulation of the effects of pozzolanic additives and corrosion inhibitor on the corrosion of reinforced concrete by artificial neural networks
, Article Revista Romana de Materiale/ Romanian Journal of Materials ; Volume 49, Issue 4 , 2019 , Pages 535-543 ; 15833186 (ISSN) ; Nobakhti, A ; Shokrgozar, A ; Afshar, A ; Sharif University of Technology
Fundatia Serban Solacolu
2019
Abstract
In this research, we simulate the corrosive behavior of steel reinforcements on 5 different mixtures to investigate the effect of two powerful protective methods, including pozzolanic additives and corrosion inhibitor on concrete, by artificial neural networks (ANNs). Related to this model, fly ash (FA), micro silica (MS), and slag were used as pozzolanic materials at an optimum 25%, 10%, and 25% of cement weight, respectively. Moreover, Ferrogard 901 as an inhibitor was also utilized. The producer recommends using12 kg/m3 to get the best possible results. The non-linear corrosion of concrete into a marine solution (3.5% NaCl) was simulated by the feed forward back propagation (FFBP)...
Simulation of the effects of pozzolanic additives and corrosion inhibitor on the corrosion of reinforced concrete by artificial neural networks
, Article Revista Romana de Materiale/ Romanian Journal of Materials ; Volume 49, Issue 4 , 2019 , Pages 535-543 ; 15833186 (ISSN) ; Nobakhti, A ; Shokrgozar, A ; Afshar, A ; Sharif University of Technology
Fundatia Serban Solacolu
2019
Abstract
In this research, we simulate the corrosive behavior of steel reinforcements on 5 different mixtures to investigate the effect of two powerful protective methods, including pozzolanic additives and corrosion inhibitor on concrete, by artificial neural networks (ANNs). Related to this model, fly ash (FA), micro silica (MS), and slag were used as pozzolanic materials at an optimum 25%, 10%, and 25% of cement weight, respectively. Moreover, Ferrogard 901 as an inhibitor was also utilized. The producer recommends using12 kg/m3 to get the best possible results. The non-linear corrosion of concrete into a marine solution (3.5% NaCl) was simulated by the feed forward back propagation (FFBP)...
Cluster approach to corrosion inhibition problems: Interaction studies
, Article Materials Chemistry and Physics ; Volume 86, Issue 2-3 , 2004 , Pages 311-314 ; 02540584 (ISSN) ; Lashgari, M ; Parsafar, Gh. A ; Sharif University of Technology
2004
Abstract
The interaction energies of 3,5 di-methyl pyridine (A) and 2,4 di-methyl pyridine (B) on the (100) surface of body-centered cubic (bcc) iron were determined via a cluster model and ab initio quantum chemical calculations at density functional theory level. The obtained energies were used to compare the inhibition behavior of these molecules for iron corrosion in hydrochloric acid solution. The iron surface and its adsorption sites (on-top, bridge, hollow) were considered as some clusters taken from two-layered 〈100〉 planes, i.e. Fe1(1), Fe4(2,2), and Fe5(4,1). So, the process for which quantum chemical calculations was carried out consists of adsorption of molecule A (B) on these clusters....
Effect of Oleuropein as Green Inhibitor on Corrosion Protection of Painted Steel
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
The corrosion rate of steel (EN 10130 DC-04) in the presence of oleuropein in aqueous corrosive solutions (of different concentrations in 1M and 0.5M hydrochloric acid and also 3.5% sodium chloride) evaluated and results was shown that oleuropein can protect steel surfaces and it acts as good inhibitor. This means that the observations of linear polarization and weight loss experiments showed inhibitor efficiency more than 97% in acidic corrosive medium and above 74% for aqueous solution of 3.5% sodium chloride. Adding oleuropein at different concentrations (i.e. 300 ppm, 700 ppm, and 1000 ppm) to three different types of polymeric paint structures (nitrocellulose alkyd base, acrylic base,...
Cluster/polarized continuum models for density functional theory investigations of benzimidazole corrosion inhibitors at metal/solution interface
, Article Corrosion ; Volume 62, Issue 3 , 2006 , Pages 199-206 ; 00109312 (ISSN) ; Arshadi, M. R ; Parsafar, Gh. A ; Sastri, U. S ; Sharif University of Technology
National Assoc. of Corrosion Engineers International
2006
Abstract
The molecular behavior of some benzimidazole (C7H 6N2) derivatives as corrosion inhibitors ojiron in hydrochloric acid (HCl) solution was investigated quantum electrochemically via the inhibitors' chemical potential (μ), molecular softness (σ), and the extent of charge transfer from the inhibitor to the metal (ΔN). These quantities were obtained from density functional theory (DFT) calculations for three models, i.e., isolated inhibitors (in vacua), inhibitors in solution, and, finally, inhibitors in electrical double layer (EDL). In these models, the effects of solvent, substrate, and electric field were considered using a polarized continuum model, iron Fe13(9,4) cluster, and a...
A simple and fast method for comparison of corrosion inhibition powers between pairs of pyridine derivative molecules
, Article Corrosion ; Volume 61, Issue 8 , 2005 , Pages 778-783 ; 00109312 (ISSN) ; Arshadi, M. R ; Parsafar, Gh. A ; Sharif University of Technology
National Assoc. of Corrosion Engineers International
2005
Abstract
Ab initio quantum chemical calculations at the density functional theory (DFT) level were performed on eight pyridine derivative molecules as corrosion inhibitors for iron in an acidic solution. In this regard, the geometry of the molecules were optimized using the B3LYP/6-31G method first, and then interactions of these optimized structures with the iron atom were explored using the B3LYP/LANL1MB method. Two modes of adsorption were considered, i.e., planar adsorption (P) via the pyridine ring and vertical adsorption (V) through a nitrogen atom. The interaction energy was minimized through the variation of the inhibitor molecule-iron atom distance. These minimum energy values, along with...
Theoretical Assessment of the Corrosion Inhibitory Effect of Some Derivatized Benzaldehyde Based Schiff Bases
, M.Sc. Thesis Sharif University of Technology ; Gobal, Freydoon (Supervisor)
Abstract
Schiff bases are used as prevalent ligands in coordination chemistry and are prepared easily. Their application as mild inhibitory agents for prevention of various steel’s corrosion in acidic solution has been proved. When their structure is altered, multi-purpose application for them is found. This property has led to a motive for research and study. In this study, electronic properties of a group of Schiff bases are investigated. The goal of this study is using quantum mechanics (QM) as a tool for specifying electronic properties of some of these bases. With respect to QM calculation which is done by density functional theory (DFT), their properties as inhibitory agents are studied. First,...
Molecular Dynamics Simulation of Aβ42 Neurotoxicity Inhibition in Order to Alzheimer’s Disease Treatment
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor) ; Saeedi, Mohammad Saeed (Supervisor)
Abstract
Alzheimer’s disease (AD) is the most common type of dementia in the elderly. The neuropathology and treatment of AD is not precisely determined yet, but according to the pathological studies, AD is associated with presence of toxic soluble oligomers and insoluble senile plaques formed by amyloidosis of Amyloid Beta (Aβ) in neocortical region of brain. An attractive therapeutic approach to treat AD is to identify small ligands that are capable of binding to critical residues in order to inhibit or reverse Aβ amyloidosis process as source of neurotoxicity. In this area, therapeutic efforts designed various organic agents and most of them focused on the N-terminal sequence of Aβ. The aim of...
An Investigation on Pitting Corrosion of 304, 316 and 316L Stainless Steels in 3.5%NaCl Solution and Effect of polyethyleneimine on Pitting Corrosion of These Steels
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdollah (Supervisor)
Abstract
In this study, pitting corrosion of 304, 316 and 316L stainless steels in 3.5% NaCl solution at different temperatures (25, 40, and 70°C), were studied by electrochemical methods such as Cyclic Potentiodynamic Polarization, Electrochemical Impedance Spectroscopy and Immersion tests. Also, the effects of different concentrations of polyethyleneimine with two molecular weights (2000 and 60000 g/mol) on pitting corrosion of these steels were investigated. Finally, the adsorption behavior of inhibitors on surface of alloys was investigated by Atomic Force Microscopy (AFM) and Attenuated Total Reflectance Fourier transform spectroscopy (ATR-FTIR). It was found that both inhibitors prevent...
Modeling of Gas Hydrate Formation in Presence of Inhibitors Using the Fuzzy Logic
, M.Sc. Thesis Sharif University of Technology ; Taghikhani, Vahid (Supervisor) ; Ghotbi, Cyrus (Supervisor)
Abstract
Nowadays oil and gas industry has taken the pulse of world energy. Different countries of the world are trying more and more to explore and produce this black gold. To do so these countries has gained many experiences and even gone to seas and oceans to find oil and gas. In the process, they has faced with a new phenomenon called gas hydrate. The phenomenon which was unknown and destructive at first after excessive research, today is even called as the future energy source of the world. But what we discussed in this study is hydrate as a problem in oil and gas industry. Gas hydrates are formed in favorable temperature and pressure condition (low temperature and high pressure) in the...
Comparative studies of some heterocyclic compounds as corrosion inhibitors of copper in phosphoric acid media
, Article Chemical Engineering Communications ; Volume 197, Issue 10 , 2010 , Pages 1303-1314 ; 00986445 (ISSN) ; Arshadi, M. R ; Biglar, M ; Sharif University of Technology
2010
Abstract
Corrosion inhibition properties of some heterocyclic compounds (3-mercapto 1,2,4 triazole, benzotriazole, thiophene, and tetra hydro-thiophene) in Cu/H3PO4 medium were investigated theoretically and experimentally via cluster/polarized continuum and gravimetric approaches. Second-order Møller-Plesset perturbation and density functional theories were applied, and the electronic chemical potential, molecular softness, and extent of charge transfer were determined for inhibitor molecules at the metal/solution interface. Good correlations were observed for both theories between the calculated quantities and experimental data. To reveal the quality of metal-inhibitor interactions, comprehensive...
Fabrication of hollow carbon spheres doped with zinc cations to enhance corrosion protection of organosilane coatings
, Article Surfaces and Interfaces ; Volume 21 , 2020 ; Mahdavian, M ; Ramazani, A ; Sharif University of Technology
Elsevier B.V
2020
Abstract
Hollow carbon spheres (HCS) are spherical forms of carbon materials that can be used as nanocontainers due to their empty cores. In this work, zinc cations were doped in HCS (Zn@HCS) from an aquatic solution of zinc nitrate salt. Corrosion inhibition of released zinc cations in saline solution on bare mild steel samples was assessed by EIS, polarization, and electrochemical noise measurements. The sample surfaces were characterized through FTIR spectroscopy and grazing incidence XRD analyses after exposure to the test solutions. The results showed improvement in the corrosion resistance in the presence of Zn@HCS in a long immersion period. Zn@HCS were also incorporated in organosilane...
A study of glycine-based dithiocarbamates as effective corrosion inhibitors for cold rolled carbon steel in HCl solutions
, Article Surfaces and Interfaces ; Volume 21 , 2020 ; Shockravi, A ; Mokarami Ghartavol, H ; Ziyaei Halimehjani, A ; Ostadrahimi, M ; Mirhosseini, S. M ; Behzadi, H ; Ghorbani, M ; Sharif University of Technology
Elsevier B.V
2020
Abstract
The corrosion inhibition of glycine-based dithiocarbamates with benzyl (BDTC) and propyl (PDTC) groups were investigated for cold rolled carbon steel (CRS) in 0.5 M HCl, indicating that the compounds as mixed type inhibitors significantly reduced the corrosion rate of the CRS due to the formation of a stable protective film on the metal surface. As confirmed by ATR-FTIR, SEM, AFM, XPS and theoretical studies, chemically adsorbed BDTC molecule is a better corrosion inhibitor with higher corrosion efficiency of about 98% at room temperature and a better thermal stability attributed to the Fe-S and Fe-N bindings, and in addition, to the presence of the benzene ring in the molecular structure. ©...