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Effects of strain-induced melt activation treatment on the microstructure and properties of Zn sacrificial anodes

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International Journal of Minerals,Metallurgy and Materials 2021年第10期28卷 1693-1704页

作者： Behrooz shayegh Boroujeny Payam Raiesi Goojani Ehsan Akbari Department of Engineering Shahrekord UniversityShahrekordIran

The microstructural properties and electrochemical performance of zinc(Zn)sacrificial anodes during strain-induced melt activation(SIMA)were investigated in this *** samples were subjected to a compressive ratio of 20%-50% at various temperatures(425-435℃)and durations(5-30 min).Short-term electrochemical tests(anode tests)based on DNV-RP-B401 and potentiodynamic polarization tests were performed in 3.5wt%NaCl solution to evaluate the electrochemical efficiency and corrosion behavior of the samples,*** electrochemical test results for the optimum sample confirmed that the corrosion current density declined by 90% and the anode efficiency slightly decreased relative to that of the raw ***-dispersive X-ray spectroscopy,scanning electron microscopy,metallographic images,and microhardness profiles showed the accumulation of alloying elements on the boundary and the conversion of uniform corrosion into localized corrosion,hence the decrease of the Zn sacrificial anode’s efficiency after the SIMA process.

关键词： strain-induced melt activation process zinc sacrificial anode corrosion resistance anode test

Synthesis, characterization and antimicrobial activity of alkaline ion-exchanged ZnO/bentonite nanocomposites

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Journal of Central South University 2016年第4期23卷 787-792页

作者： Hamideh Pouraboulghasem Mohammad Ghorbanpour Razieh shayegh Samaneh Lotfiman Department of Food Science Islamic Azad University-Sarab Branch Sarab Iran Chemical Engineering Department University of Mohaghegh Ardabili Ardabil Iran

Nanocomposites of zinc/bentonite clay were synthesized for use as an antibacterial material by a quick and simple alkaline ion exchange method. The synthesis of zinc doped bentonite nanocomposite was accomplished by placing bentonite in a melting bath of ZnSO4 for 10, 20, 40, 60 and 90 rain. The complexes were characterized by XRD, SEM and DRS. XRD analyses and SEM observations confirmed the diffusion of zinc to the clay surfaces. Antibacterial activity tests against Escherichia coli showed that bentonite did not present any antibacterial properties, but after alkaline ion exchange treatment, inhibition was noted. The highest antibacterial activity was observed with ZnO/bentonite composite alkaline ion exchange for 60 and 90 rain. Interestingly, the leaching test indicated that ZnO/bentonite did not present any risk for drinking water treatment.

关键词： alkaline ion exchange ZnO/bentonite nanocomposite antibacterial activity

The Volterra-Lyapunov matrix theory for global stability analysis of a model of the HIV/AIDS

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International Journal of Biomathematics 2017年第1期10卷 13-33页

作者： Moosarreza Shamsyeh Zahedi Narges shayegh Kargar Department of Mathematics Payame Noor University P. O. Box 19395-3697 Tehran Iran

In this paper, we analyze a nonlinear mathematical model of the HIV/AIDS and screening of unaware infectives on the transmission dynamics of the disease in a homoge- neous population with constant immigration of susceptibles incorporating use of condom, screening of unaware infectives and treatment of the infected. We consider constant con- trols and thereafter by incorporating the theory of Volterra-Lyapunov stable matrices into the classical method of Lyapunov functions, we present an approach for global stability analysis of HIV/AIDS. The analysis and results presented in this paper make building blocks toward a comprehensive study and deeper understanding of the funda- mental mechanism in HIV/AIDS. A numerical study of the model is also carried out to investigate the analytical results.

关键词： Global stability human immunodeficiency virus (HIV) dynamical systems Volterra-Lyapunov stability.

Characterizations of dissimilar S32205/316L welds using austenitic, super-austenitic and super-duplex filler metals

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International Journal of Minerals,Metallurgy and Materials 2020年第1期27卷 119-127页

作者： A.Taheri B.Beidokhti B.shayegh Boroujeny A.Valizadeh Department of Materials Engineering Najafabad BranchIslamic Azad UniversityIsfahan ***Iran Materials and Metallurgical Engineering Department Faculty of EngineeringFerdowsi University of MashhadMashhad ***Iran Department of Engineering Shahrekord UniversityShahrekord 88186-34141Iran Brunel Centre for Advanced Solidification Technology(BCAST) Brunel UniversityUxbridge UB83PHUK

UNS S32205 duplex stainless steel plates were welded to AISI 316 L stainless steel using the pulsed gas tungsten arc welding process with three different filler metals: ER2594, ER312, and ER385. The microstructures of the welds were characterized using optical and scanning electron microscopy, and all of the specimens were evaluated by ferrite measurements. The mechanical properties were studied through hardness,tensile, and impact tests. In addition, the pitting resistance equivalent number was calculated and cyclic polarization tests were performed to evaluate the corrosion resistance of the weld metal. The results showed that chromium nitride was formed in the heat-affected zone of the duplex side,whereas no sigma phase was detected in any of the specimens. The ferrite number increased from the root pass to the final pass. The absorbed energies of the impact test decreased with increasing ferrite number, whereas the tensile strength was enhanced. The fully austenitic microstructure of the specimen welded with ER385 exhibited the highest resistance to pitting corrosion at 25°C, and the super-duplex weld metal presented superior corrosion resistance at 50°C.

关键词： stainless steel mechanical properties microstructure welding

Super gas wet and gas wet rock surface: State of the art evaluation through contact angle analysis

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Petroleum 2023年第1期9卷 1-7页

作者： Mohammad Azadi Tabar Abolfazl Dehghan Monfared Flor shayegh Farzad Barzegar Mohammad Hossein Ghazanfari Department of Chemical and Petroleum Engineering Sharif University of TechnologyTehran11155-9564Iran Department of Petroleum Engineering Faculty of PetroleumGas and Petrochemical EngineeringPersian Gulf UniversityBushehr75169-13817Iran Research Institute of Petroleum Industry Tehran14665-137Iran

Recently,super gas wet and gas wet surfaces have been extensively attended in petroleum industry,as supported by the increasing number of publications in the last decade related to wettability alteration in gas condensate *** many cases,contact angle measurement has been employed to assess the wettability *** though contact angle measurement seems to be a straightforward approach,there exist many misuses of this technique and consequently misinterpretation of the corresponding *** this regard,a critical inspection of the most recent updated concepts and the intervening parameters in the contact angle based wettability evaluation of liquid-solid-gas systems could aid to provide some remediation to alleviate this *** this end,this work presents a survey on the accurate terms and rigorous protocols based on the community of surface science and *** a preliminary step,advancing,receding,static,and the most stable contact angle terminology are *** study is followed by the definition of the contact angle hysteresis *** application of surface free energy in the selection of the best gas wet agent is then ***,the impact of the size-dependent behavior of drop on contact angle is ***,a sessile drop experiment is explained to achieve the defined *** future contributions to petroleum industry journals,like this journal,this work could offer an easy use of the conceptual framework for analyzing the results and comparative evaluations in chemical wettability modifier agents.

关键词： Contact angle hysteresis Size-dependent behavior Surface free energy Stick-slip Wettability alteration Condensate reservoirs

Effect of in ovo ghrelin administration on serum malondialdehyde level in newly-hatched chickens

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Asian Pacific Journal of Tropical Biomedicine 2012年第1期2卷 47-49页

作者： Alireza Lotfi Habib Aghdam Shahryar Yahya Ebrahimnezhad Jalal shayegh Department of Animal Science Shabestar BranchIslamic Azad University Department of Veterinary Medicine Shabestar BranchIslamic Azad University

Objective:To investigate effects of in ovo ghrelin administration on serum malondialdehyde(MDA)level in newly-hatched ***:Fertilized eggs were divided into 7 groups:group Tl as control(without injection),group T2(in ovo injected with 50 ng/egg ghrelin on day 5),group T3(in ovo injected with 100 ng/egg ghrelin on day 5),group T4(in ovo injected with 50 ng/egg ghrelin on day 10),group T5(in ovo injected with 100 ng/egg ghrelin on day 10),group T6(in ovo injected with solvent:1%acetic acid,without ghrelin on day 5)and group T7(in ovo injected with solvent without ghrelin on day 10).After hatching,serum MDA concentrations were ***:Chrelin administrated groups(T2,T3,T4 and T5)had lower serum MDA level in comparison with control group(T1)or solvent injected groups(T6 and T7).T2 and T3(ghrelin injection on day 5)had significantly lower MDA concentrations(4.10 and 4.60 nmol/mL,respectively)in comparison with other *** T4 and T5,MDA levels were lower than T1,T6 and T7(non-ghrelin administrated groups)(9.53 and 9.50 in comparison with 10.73,10.03 and 10.13 nmol/mL)and were higher than T2and ***:It can be concluded that in ovo administration of ghrelin can have antioxidative protection and reduce serum MDA *** administration on day 5 of incubation is more efficient.

关键词： Chicken Ghrelin In ovo injection Malondialdehyde Oxidative stress Antioxidative protection Incubation Acetic acid

Small Indian mongoose(Herpestes auropunctatus)in Iran:first evidence for the infection with Spirura sp.(Nematoda:Spiruridae)

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Journal of Coastal Life Medicine 2014年第11期 899-902页

作者： Ehsan Rakhshandehroo Hassan Sharifiyazdi Hossein shayegh Amin Ahmadi Department of Pathobiology School of Veterinary MedicinShiraz UniversityShirazIran Department of Clinical Studies School of Veterinary MedicinShiraz UniversityShirazIran

Objective:To investigate the infection with gastrointestinal helminthes in small Indian mongooses(Herpestes auropunctatus)and its epidemiologic aspects in ***:During June 2012 to July 2013,a total of 13 small Indian mongooses were caught using live trap boxes in an area located near Shiraz,southern of *** animals were euthanized,eviscerated and parts of the alimentary tract were *** mongooses showed a nematode attached to the mucosa of the ***:According to the main morphological characteristics,the specimens belonged to the genus Spirura(Blanchard 1849).This study represents the first evidences of the infection withSpirura *** Herpestes auropunctatus in the ***:Because the animal can invade and appear in the habitat of the other animal populations including omnivores or carnivores,it seems that mongooses in this area could have a high potential for the transmission of the infection with the spirurid nematodes to a large range of ***,besides the necessity of conducting the controlling programs,autochthonous dogs,cats and rodents should be included in more epidemiological studies in this region.

关键词： Small Indian mongoose Herpestes auropunctatus Spirura Southern Iran