Taheri H.,Kish University |
Dolati A.,Sharif University of Technology |
Beidokhti B.,Ferdowsi University of Mashhad
Anti-Corrosion Methods and Materials | Year: 2015
Purpose – This paper aims to clarify the corrosion behavior of two famous structural steels in sour environment. These steels have a vast application in oil and gas industries. The study aims to find the effect of different concentrations of sour solution on the origin of crack in these steels. Design/methodology/approach – After preparation of specimens, different sour solutions were made using the synthetic brine (according to National Association of Corrosion Engineers [NACE], Technical Committee Report 1D182) and various amounts of Na2S.9H2O and CH3COOH. The polarization test was done by Potansiostat apparatus model Zahner-IM6 at two temperatures, 25°C and 50°C. The corrosion current densities were obtained from the polarization curves. Finally, the corrosion products and hydrogen-induced cracking (HIC) were investigated by Tescan Vega II XMU scanning electron microscope (SEM) linked to a Rontec energy-dispersive X-ray spectroscopy (EDS) system. Findings – API 5L-X70 steel showed smaller corrosion current values than A516-Gr70 steel. The HIC cracks propagated parallel to the surface of A516-Gr70 steel in three solutions and confirmed the inappropriateness of this steel for sour environment applications. Originality/value – This paper studies the effect of sour environment on the behavior of two famous industrial steels at two temperatures by new method. © 2015, Emerald Group Publishing Limited.
Ghadamyari M.,Kish University |
Moayed M.H.,Ferdowsi University of Mashhad |
Davoodi A.,Kharazmi University
Journal of Corrosion Science and Engineering | Year: 2012
The effectiveness of 1% tin (Sn) on preventing Cu-30Zn alloys from corrosion in sulphide polluted 3.5% NaCl solution was studied by AC and DC electrochemical techniques. The EIS results showed that a double-loop capacitive circuit could characterize the surface reactions. Moreover, corrosion resistance of surface layer formed on the alloy was remarkably less than the charge transfer resistance. Furthermore, increasing in Na2S concentration slightly increases the corrosion rate of alloy, confirming the potentiodynamic polarizations studies. Moreover, tin reduces the corrosion rate by forming SnO2 as a protecting layer and by shifting corrosion potential toward positive values. © 2012 University of Manchester and the authors.
Akbari M.,Islamic Azad University at Tehran |
Berenji S.,Kish University |
Reza A.,Alzahra University
ICETC 2010 - 2010 2nd International Conference on Education Technology and Computer | Year: 2010
Static vulnerability Detection approach usually produces large amount of false positives. To achieve better result, a tool which is able to understand the analyzed source code and join it to high level programming concepts is needed. The proposed tool presents in this paper provides a novel semantic level method for detecting C language source code vulnerabilities. In a programming language each vulnerability is correlated to a valid code in point of compiler view. In other word, a written code in a particular situation may cause a vulnerability. To implement this tool, a collection of vulnerability attribute (VA) that represented a source code pattern for each vulnerability is prepared. Then the relation of these VAs in a pattern is extracted. In continue the parse tree of estimating source code was generated. Vulnerability detection is done in two general steps; first the generated parse tree is traversed by DFS and annotated, then vulnerability detection rules (VR) are performed on annotated tree to find code weaknesses. In this paper proposed tool is compared with other vulnerability detection tools. The comparison shows that the tool is useful for finding buffer overflow flaws with low false positive rate. © 2010 IEEE.
Kakooei S.,Petronas University of Technology |
Kakooei S.,Kish University |
Akil H.M.,Universiti Sains Malaysia |
Dolati A.,Kish University |
And 2 more authors.
Construction and Building Materials | Year: 2012
One effective method for preventing corrosion of steel reinforcement and improving the mechanical properties of concrete is changing the physical nature of concrete by adding different materials. In this study, we have used polypropylene fibers as an additional material. We have compared the corrosion rate of rebar using different volume ratios and sizes of polypropylene fibers. Reinforcement potential increased as the amount of fibers increased from 0 to 2 kg m -3. The polypropylene fibers delay the initial corrosion process by preventing cracking, thereby decreasing permeability of the concrete. In addition, the corrosion rate of concrete samples made with Kish Island coral aggregate was compared to samples made with a siliceous aggregate. The corrosion rate in this concrete is more than twice that in siliceous concrete. We concluded that coral aggregate is improper for making concrete and using in concrete structures in the onshore atmosphere. © 2012 Elsevier Ltd. All rights reserved.