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Microstructural evolution and creep properties of Mg-4Sn alloys by addition of calcium up to 4 wt.%

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Transactions of Nonferrous Metals Society of China 2020年第4期30卷 896-904页

作者： Amir BAGHANI Hamid KHALILPOUR seyed mahdi MIRESMAEILI Department of Mechanical Engineering University of IowaIowa CityIAUSA Department of Mining Metallurgical and Materials EngineeringLaval UniversityQuebecCanada Faculty of Mechanical Engineering Shahid Rajaee Teacher Training UniversityTehranIran

The effects of addition of calcium up to 4 wt.% on the microstructure and creep properties of Mg-4 Sn alloys were investigated by the impression creep test. Impression creep tests were performed in temperature range between 445 and 475 K under normalized stresses σ/G(where σ is the stress;G is the shear modulus) between 0.0225 and 0.035. Optical microscopy and scanning electron microscopy were used to study the microstructure of samples. It is observed that the addition of Ca more than 2 wt.% suppresses less stable Mg Sn2 phase, and instead forms more thermally stable phases of Ca-Mg-Sn and Mg2 Ca at the grain boundaries which improve the creep resistance of Mg-4 Sn alloys. According to the stress exponents(6.04

关键词： impression creep test Mg-Sn-Ca alloy creep mechanism microstructure

Assessment of the anterior chamber parameters after laser iridotomy in primary angle close suspect using Pentacam and gonioscopy

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International Journal of Ophthalmology(English edition) 2013年第5期6卷 680-684页

作者： Alireza Esmaeili Behzad Barazandeh Sina Ahmadi Alireza Haghi seyed mahdi Ahmadi Hosseini Fereshteh Abolbashari Department of Ophthalmology Razavi Hospital Refractive Error Research Center School of Paramedical SciencesMashhad University of Medical Sciences

AIM:To evaluate the changes in the anterior segment parameters of the subjects with primary angle closure suspect(PACS) before and after laser iridotomy(LI) using the Pentacam and gonioscopy. METHODS:Forty-eight eyes of 48 PACS were *** chamber angle(ACA),central anterior chamber depth(ACD),anterior chamber volume(ACV) and central corneal thickness(CCT) were recorded from the Pentacam before and one month after *** was graded according to Shaffer classification using Goldmann ***:ACA increased significantly from 25.59±4.41 to 26.46±4.33 degrees(P=0.009) and ACV changed from 85.97±16.07mm3to 99.25±15.83mm3(P=0.000).The changes in ACD,CCT and intraocular pressure were non-significant(P>0.05).Gonioscopy showed significant widening of the Shaffer angle in 4 quadrants(P<0.001).CONCLUSION:Pentacam can serve as the objective instrument in assessing the efficacy of LI.

关键词： glaucoma laser iridotomy Pentacam angle closure gonioscopy

Effect of Gd3+-,Pr3+-or Sm3+-substituted cobalt-zinc ferrite on photodegradation of methyl orange and cytotoxicity tests

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Journal of Rare Earths 2019年第12期37卷 1288-1295页

作者： seyed mahdi Peymani-Motlagh Nadia Moeinian Mojtaba Rostami mahdi Fasihi-Ramandi Ali Sobhani-Nasab Mehdi Rahimi-Nasrabadi Mohammad Eghbali-Arani Mohammad Reza Ganjali Teofil Jesionowski Hermann Ehrlich Mohammad Ali Karimi Narges Ajami Department of Chemistry Imam Hossein UniversityTehran 16765-3454Iran Department of Chemistry Payame Noor UniversityTehran 19395-4697Iran Young Researchers and Elite Club Karaj BranchIslamic Azad UniversityKaraj ***Iran Molecular Biology Research Center Systems Biology and Poisoning InstituteBaqiyatallah University of Medical SciencesTehran ***Iran Social Determinants of Health(SDH)Research Center Kashan University of Medical SciencesKashan ***Iran Core Research Lab Kashan University of Medical SciencesKashan ***Iran Faculty of Pharmacy Baqiyatallah University of Medical SciencesTehran 195163759Iran Department of Physics University of KashanKashan ***Iran Center of Excellence in Electrochemistry Faculty of ChemistryUniversity of TehranTehran ***Iran Institute of Chemical Technology and Engineering Faculty of Chemical TechnologyPoznan University of TechnologyPoznan 60965Poland Institute of Electronic and Sensor Materials TU Bergakademie FreibergFreiberg 09599Germany

Gd3+-,Pr3+-or Sm3+-doped Co-Zn(Co0.5Zn0.5Fe2 O4)magnetic ferrites(i.e.,Co0.5Zn0.5Gd0.1Fe1.9O4,Co0.5Zn0.5Pr0.1Fe1.9O4 and Co0.5Zn0.5Sm0.1Fe1.9O4)were prepared using a facile sol-gel approach,and the structure,surface morphology and chemical composition of the products were studied by means of scanning electron microscopy(SEM),energy dispersive X-ray analysis(EDX),X-ray diffraction(XRD),UVvisible diffuse reflectance spectroscopy(DRS),photoluminescence(PL)spectroscopy,Fourier transform infrared spectroscopy(FT-IR)and vibrating sample magnetometer(VSM)*** patterns show the Co-Zn product is composed of cubic spinel phases with few impurities or secondary phases,and the average crystallite sizes of the samples are determined to be approximately^51—80,~99—181,~68—103 and^83—133 *** the coercivity and remnant and saturation magnetizations,evaluated by vibrating sample magnetometer(VSM),are found to increase linearly with the incorporation of Gd3+,Pr3+and Sm3+in the product *** CO1-xZnxFe2-yRyO4 photocatalyst sample is found to display a red shift in its absorption,and exhibits outstanding photocatalytic effects in the degradation of MO under ultraviolet(UV)*** is attributed to the reduction of the band gap of cobalt-zinc ferrite due to the presence of rare earth *** in vitro evaluations of the cytotoxic effects of the synthesized nanoparticles were performed on a HeLa cell line.

关键词： Magnetic ferrite Rare earth ions Photocatalyst Cytotoxicity Sol-gel

Kinetic studies of the oxidative coupling of methane over the Mn/Na_2WO_4/SiO_2 catalyst

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Journal of Natural Gas Chemistry 2009年第1期18卷 25-34页

作者： seyed Mehdi Kamali Shahri seyed Mehdi Alavi Reaction Engineering Lab. Chemical Engineering Department Iran University of Science and Technology Tehran-Iran

Oxidative coupling of methane is a direct way to obtain C2 hydrocarbon, and Mn-Na-W/SiO2 catalyst is the most promising among all the catalysts. The 2%Mn/5%Na2WO4/SiO2 catalyst was prepared by the incipient wetness impregnation method. A 7-step heterogeneous reaction model of the oxidative coupling of methane to C2 hydrocarbons was conducted by co-feeding methane and oxygen at a total pressure of 1 bar over the catalyst. The kinetic measurements were carried out in a micro-catalytic fixed bed reactor. The kinetic data were obtained at the appropriate range of reaction conditions （4 kPa〈Po2 〈20 kPa, 20 kPa〈PcH4〈80 kPa, 800 ℃〈T〈900℃）. The proposed reaction kinetic scheme consists of three primary and four consecutive reaction steps. The conversions of hydrocarbons and carbon oxides were evaluated by applying Langmuir-Hinshelwood type rate equations. Power-law rate equation was applied only for the water-gas shift reaction. In addition, the effects of operating conditions on the reaction rate were studied. The proposed kinetic model can predict the conversion of methane and oxygen as well as the yield of C2 hydrocarbons and carbon oxides with an average accuracy of ± 15%.

关键词： kinetic model oxidative coupling of methane reaction rate

Study of M-ZSM-5 nanocatalysts(M: Cu, Mn, Fe, Co …) for selective catalytic reduction of NO with NH_3: Process optimization by Taguchi method

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Chinese Journal of Chemical Engineering 2015年第10期23卷 1647-1654页

作者： Parvaneh Nakhostin Panahi Darush Salari Aligholi Niaei seyed mahdi Mousavi Department of Chemistry Faculty of Science University of Zanjan Department of Applied Chemistry Faculty of Chemistry University of Tabriz Department of Chemical Engineering & Petroleum University of Tabriz Faculty of Chemistry University of Kashan

A series of different transition metals(V,Co,Cr,Mn,Fe,Ni,Cu and Zn) promoted H-ZSM-5 catalysts were prepared by impregnation method and characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM) and transmission electron microscopy(TEM).The catalytic activity of these catalysts was evaluated for the selective catalytic reduction(SCR) of NO with NH_3 as reductant in the presence of *** results revealed that the catalytic activity of Cu-ZSM-5 nanocatalyst for NO conversion to N_2 was 80%at 300 ℃,which was the best among various promoted *** of experiments(DOEs) with Taguchi method was employed to optimize NH_3-SCR process parameters such as NH_3/NO ratio,O_2 concentration,and gas hourly space velocity(GHSV) over Cu-ZSM-5 nanocatalyst at 250 and 300 ℃.Results showed that the most important parameter in NH_3-SCR of NO is O_2 concentration;followed by NH_3/NO ratio and GHSV has little *** NO conversion to N_2 of 63.1%and 94.86%was observed at 250℃ and 300℃,respectively under the obtained optimum conditions.

关键词： NO SCR ZSM-5 Transition metal Taguchi method

Assessment of fracture process in forta and polypropylene fiber-reinforced concrete using experimental analysis and digital image correlation

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Frontiers of Structural and Civil Engineering 2022年第12期16卷 1633-1652页

作者： seyed Hamid KALALI Hamid ESKANDARI-NADDAF seyed Ali EMAMIAN Department of Civil Engineering Hakim Sabzevari UniversitySabzevar ***Iran

This paper aims to characterize the evolution of the fracture process and the cracking behavior in fortaferro(FF)and polypropylene(PP)fiber-reinforced concrete under the uniaxial compressive loading using experimental analysis and digital image correlation(DIC)on the surface *** this purpose,6 mix designs,including two FF volume fractions of 0.10%,and 0.20%and three PP volume fractions of 0.20%,0.30%,and 0.40%,in addition to a control mix were evaluated according to compressive strength,modulus of elasticity,toughness index,and stress–strain *** influence of fibers on the microstructural texture of specimens was analyzed by scanning electron microscope(SEM)*** show that FF fiber-reinforced concrete specimens demonstrated increased ductility and strength compared to PP *** results revealed that the major crack and fracture appeared at the peak load of the control specimen due to brittleness and sudden gain of large lateral strain,while a gradual increase in micro-crack quantity at 75%of peak load was observed in the fiber specimens,which thenbegan to connect with each other up to the final *** accuracy of the results supports DIC as a reliable alternative for the characterization of the fracture process in fiber-reinforced concrete.

关键词： fiber-reinforced concrete forta-ferro and polypropylene fiber fracture process cracking behavior digital image correlation

Large-scale seismic isolation through regulated liquefaction： a feasibility study

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Earthquake Engineering and Engineering Vibration 2016年第4期15卷 579-595页

作者： seyed Amin Mousavi Morteza Bastami seyed Mehdi Zahrai School of Civil Engineering College of Engineering University of Tehran Tehran Iran International Institute of Earthquake Engineering and Seismology TehranIran Center of Excellence for Engineering and Management of Civil Infrastructures School of Civil Engineering Faculty of EngineeringUniversity of Tehran Tehran Ivan

Using controlled liquefaction, a seismic isolation technique is introduced by which a large area with dozens of structures can be seismically isolated. The proposed Large Scale Seismic Isolation （LSSI） is in many ways similar to conventional base isolations. The required bearing is provided by a fully undrained pre-saturated liquefiable layer which has substantial vertical stiffness/capacity and minimal lateral stiffness. Moreover, required energy dissipation would be provided through material damping and Biot flow-induced damping within the liquefied layer. LSSI consists of a thick non- liquefiable crust layer and an underlying engineered pre-saturated liquefiable layer bounded by two impermeable thin clay layers. The liquefiable layer should be designed to trigger liquefaction as soon as possible within the early seconds of a design level seismic event. Adopting the energy-based GMP liquefaction theory, optimum gradation of the liquefiable layer is also investigated. It tumed out that LSSI would effectively reduce acceleration response spectrum within short to medium periods. Contribution of the proposed LSSI is more pronounced in the case of stronger ground motions such as near field events as well as ground motions with longer return periods.

关键词： liquefaction seismic isolation effective stress analysis ground response analysis passive control

Correlation of the mean activity coefficient of aqueous electrolyte solutions using an equation of state

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Chinese Journal of Chemical Engineering 2016年第10期24卷 1456-1463页

作者： seyed Hossein Mazloumi Chemical Engineering Department Faculty of EngineeringFerdowsi University of Mashhad

Accurate calculation of thermodynamic properties of electrolyte solution is essential in the design and optimization of many processes in chemical industries. A new electrolyte equation of state is developed for aqueous electrolyte solutions. The Carnahan-Starling repulsive model and an attractive term based on square-well potential are adopted to represent the short range interaction of ionic and molecular species in the new electrolyte EOS. The long range interaction of ionic species is expressed by a simplified version of Mean Spherical Approximation theory （MSA）. The new equation of state also contains a Born term for charging free energy of ions. Three adjustable parameters of new eEOS per each electrolyte solution are size parameter, square-well potential depth and square-well potential interaction range. The new eEOS is applied for correlation of mean activity coefficient and prediction of osmotic coefficient of various strong aqueous electrolyte solutions at 25℃ and 0.1 MPa. In addition, the extension of the new eEOS for correlation of mean activity coefficient and solution density of a few aqueous electrolytes at temperature range of 0 to 100℃ is carried out.

关键词： Aqueous electrolyte solution Electrolyte equation of state Activity coefficient Osmotic coefficient Solution density

Creep rupture assessment for Level-2 PSA of a 2-loop PWR： accounting for phenomenological uncertainties

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Nuclear Science and Techniques 2017年第8期28卷 117-125页

作者： Faramarz Yousefpour seyed Mohsen Hoseyni seyed Mojtaba Hoseyni seyed Ali Hashemi Olia Kaveh Karimi Nuclear Science and Technology Research Institute TehranIran Young Researchers and Elite Club East Tehran BranchIslamic Azad University Tehran Iran

The Level-2 probabilistic safety assessment(PSA) of pressurized water reactors studies the possibility of creep rupture for major reactor coolant system components during the course of high pressure severe accident sequences. The present paper covers this technical issue and tries to quantify its associated phenomenological uncertainties for the development of Level-2 PSA. A framework is proposed for the formal quantification of uncertainties in the Level-2 PSA model of a PWR type nuclear power plant using an integrated deterministic and PSA approach. This is demonstrated for estimation of creep rupture failure probability in station blackout severe accident of a 2-loop PWR, which is the representative case for high pressure sequences. MELCOR 1.8.6 code is employed here as the deterministic tool for the assessment of physical phenomena in the course of accident. In addition, a MATLAB code is developed for quantification of the probabilistic part by treating the uncertainties through separation of aleatory and epistemic sources of *** probability for steam generator tube creep rupture is estimated at 0.17.

关键词：模型不确定性蠕变断裂 PSA 压水堆断裂评价二级现象学反应堆冷却剂系统