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Plasma Science and Technology 2013年第6期15卷 586-592页

作者： Vahid abbasi Ahmad GHOLAMI Kaveh NIAYESH Electrical Engineering Department Iran University of Science and TechnologyNarmakTehranIran School of Electical and Computer Engineering College of EngineeringUniversity of TehranIR-14395 TehranIran

In a gas circuit breaker,metal vapor resulting from electrode erosion is injected into the arc *** arc then burns in a mixture of SF;and electrode vapor,which has properties significantly different from those of pure SF;.Thermodynamic properties and transport coefficients of thermal plasmas formed in SF;-copper vapor mixtures change as a function of temperature and *** property that is mostly affected by the presence of copper is electrical conductivity,which is important in magnetohydrodynamic（MHD） *** this study,the transport coefficients of SF;in the presence of 10 percent copper are considered as the basis of MHD *** are made between the results during arc formation for pure SF;and SF;-Cu mixture in a medium voltage（MV） circuit *** to the transport coefficients influenced by the SF;-Cu mixture,the distribution of the electric potential, temperature,electromagnetic force density and current density of the arc column are presented and ***,the arc stability and pinch effect near current zero with 3-D simulation are investigated,which is advantageous to improving the efficiency of arc plasma simulation.

关键词： magnetohydrodynamic(MHD) electromagnetic force SF6-Cu mixture transport coefficients pure SF6

Measurement and Monte Carlo simulation of γ-ray dose rate in high-exposure building materials

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Nuclear Science and Techniques 2017年第2期28卷 30-34页

作者： A. abbasi M. Hassanzadeh Reactor Research School Nuclear Science and Technology Institute (NSTRI) P.O. Box 141551339 Tehran Iran University of Kyrenia Kyrenia North Cyprus Mersin 10Turkey

Natural radioactivity radionuclides in building materials, such as^(226)Ra,^(232)Th and^(40)K, cause indoor exposure due to their gamma-rays. In this research, in a standard dwelling room(5.0 m 9 4.0 m 9 2.8 m), with the floor covered by various granite stones, was set up to simulate the dose rates from the radionuclides using MCNP4 C code. Using samples of granite building products in Iran, activities of the^(226)Ra,^(232)Th and^(40)K were measured at 3.8–94.2, 6.5–172.2 and 556.9–1529.2 Bq kg^(-1),respectively. The simulated dose rates were26.31–184.36 n Gy h^(-1), while the measured dose rates were 27.70–204.17 n Gy h^(-1). With the results in good agreement, the simulation is suitable for any kind of dwelling places.

关键词： Radioactivity Building materials Absorbed dose Experimental MCNP4C

Three-Dimensional Simulation of Plasma Deformation During Contact Opening in a Circuit Breaker,Including the Analysis of Kink Instability and Sausage Instability

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Plasma Science and Technology 2012年第11期14卷 996-1001页

作者： Vahid abbasi Ahmad GHOLAMI Kaveh NIAYESH High Voltage and Magnetic Material Research Center Electrical Engineering DepartmentIran University of Science and Technology School of Electrical and Computer Engineering University of Tehran

A three-dimensional （3-D） transient model has been developed to investigate plasma deformation driven by a magnetic field and its influence on arc stability in a circuit breaker. The 3-D distribution of electric current density is obtained from a current continuity equation along with the generalized Ohm＇s law; while the magnetic field induced by the current flowing through the arc column is calculated by the magnetic vector potential equation. When gas interacts with an arc column, fundamental factors, such as Ampere＇s law, Ohm＇s law, the turbulence model, transport equations of mass, momentum and energy of plasma flow, have to be coupled for aria- lyzing the phenomenon. The coupled interactions between arc and plasma flow are described in the fl＇amework of time-dependent magnetohydrodynamic （MHD） equations in conjunction with a K-~ turbulence model. Simulations have been focused on sausage and kink instabilities in plasma （these phenomena are related tO pinch effects and electromagnetic fields）. The 3-D sjm- ulation reveals the relation between plasma deformation and instability phenomena, which affect arc stability during circuit breaker operation. Plasma deformation is the consequence of coupled interactions between the electromagnetic force and plasma flow described in simulations.

关键词： magnetohydrodynamic (MHD) plasma deformation electromagnetic force kink instability sausage instability

A Novel Process in Semi-Solid Metal Casting

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Journal of Materials Science & Technology 2012年第10期28卷 946-950页

作者： Bijan abbasi-Khazaei Saeid Ghaderi Department of Material Eng. Faculty of Eng.Razi University

In this research a new process for semi-solid casting of ductile iron based on the high nucleation rate combined with locally mechanical stirring is presented. In this process at first fully liquid ductile iron was poured on the peripheral surface of a wheel rotating against pouring direction. At this stage, the solid crystals nucleated at the chilling surface were pushed to the melt by a heat resistance steel cutter and finally the semi-solid slurry was generated. Reheating treatment was done on the samples to achieve more efficiency of semi-solid casting process. The effects of the travelling distance of solid particles during casting, the reheating time and temperature were examined. The results showed that the process effectively changes the dendrite structure to globular one.

关键词： Semi-solid Casting Ductile cast iron

Microstructural Characteristics and Mechanical Properties of Low-Alloy, Medium-Carbon Steels After Multiple Tempering

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Acta Metallurgica Sinica(English Letters) 2019年第1期32卷 74-88页

作者： Erfan abbasi Quanshun Luo Dave Owens Materials and Engineering Research Institute Sheffield Hallam University Tyzack Machine Knives Ltd

The microstructure and mechanical properties of NiCrMoV-and NiCrSi-alloyed medium-carbon steels were investigated after multiple tempering. After austenitising, the steels were hardened by oil quenching and subsequently double or triple tempered at temperatures from 250 to 500 °C. The samples were characterised using scanning electron microscopy and X-ray diffraction, while the mechanical properties were evaluated by Vickers hardness testing, V-notched Charpy impact testing and tensile testing. The results showed that the retained austenite was stable up to 400 °C and the applied multiple tempering below this temperature did not lead to a complete decomposition of retained austenite in both steels. It was also found that the microstructure, hardness and impact toughness varied mainly as a function of tempering temperature,regardless of the number of tempering stages. Moreover, the impact toughness of NiCrMoV steel was rather similar after single/triple tempering at different temperatures, while NiCrSi steel exhibited tempered martensite embrittlement after single/double tempering at 400 °C. The observed difference was mainly attributed to the effect of precipitation behaviour due to the effect of alloying additions in the studied steels.

关键词： Medium-carbon steels Multiple tempering Alloying addition Mechanical properties Retained austenite Precipitation behaviour

Fixed points stability,bifurcation analysis,and chaos control of a Lotka-Volterra model with two predators and their prey

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International Journal of Biomathematics 2024年第4期17卷 1-38页

作者： Muhammad Aqib abbasi Department of Mathematics Quaid-I-Azam University Islamabad44230Pakistan

The study of the population dynamics of a three-species Lotka-Volterra model is crucial in gaining a deeper understanding of the delicate balance between prey and predator *** research takes a unique approach by exploring the stability of fixed points and the occurrence of Hopf *** using the bifurcation theory,our study provides a comprehensive analysis of the conditions for the existence of Hopf *** is validated through detailed numerical simulations and visual representations that demonstrate the potential for chaos in these *** mitigate this instability,we employ a hybrid control strategy that ensures the stability of the controlled model even in the presence of Hopf *** research is not only significant in advancing the field of ecology but also has far-reaching practical implications for wildlife management and conservation *** results provide a deeper understanding of the complex dynamics of prey-predator interactions and have the potential to inform sustainable management practices and ensure the survival of these species.

关键词： Fixed points existence and uniqueness Hopf bifurcation

Biodiversity of vespid wasps in spatial and temporal dimensions in northern Zanjan Province of Iran

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生态学杂志 2008年第5期27卷 797-802页

作者： Roohollah abbasi Maedeh Mashhadikhan Mehdi abbasi Bahrain Kiabi Department of Biology Faculty of Science Shahid Beheshti University Tehran Iran Department of Biology Facuhy of Science Islamic Azad University-Damghan Branch Damghan Iran Department of Irrigation Faculty of Agriculture University of Zabol Zabol Iran

Vespidae is one of the major families of Hymenoptera with more than 115000 described species. In the present paper, Simpson and Shannon-Wiener diversity indices, Simpson, Camargo, Smith and Wilson, and modified Nee evenness indices, and richness index based on rarefaction method were adopted to study the biodiversity of vespid wasps in spatial and temporal dimensions in northern Zanjan Province of Iran. In spatial dimension, Zanjan and Gilvan showed the highest and the lowest species diversity, evenness, and richness, respectively; while in temporal dimension, 16 July-6 August showed the highest species diversity and richness, and 18 May-27 May and 23 August-2 September showed the highest and the lowest species evenness, respectively. Significant differences in species abundance between localities of study area were observed by Kruskal-Wallis nonparametric test.

关键词：生物多样性黄蜂伊朗生活性性

Repetitive Thermomechanical Processing towards Ultra Fine Grain Structure in 301,304 and 304L Stainless Steels

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Journal of Materials Science & Technology 2011年第4期27卷 338-343页

作者： A.Momeni S.M.abbasi Department of Mining and Metallurgical Engineering Amirkabir University of Technology KNT University of Technology

Thermomechanical processing as a combination of cold rolling and annealing was performed on austenitic stainless steels 301,304 and 304L. Two cold rolling steps each one up to a reduction of 75% were combined with an intermediate annealing at 800℃ for 20 min. The final annealing was performed *** same temperature and time. Cold rolling contributed to martensite formation at the expense of metastable austenite in the studied materials. Austenite in 301 was found to be less stable than that in 304 and 304L. Hence, higher strength characteristics in the as-quenched 301 stainless steels were attributed to the higher volume fraction of martensite. Both α′-martensite and ε-martensite were found to form as induced by deformation. However, the intensity of ε-martensite increased as the stability of austenite decreased. Annealing after cold rolling led to the reversion of austenite with an ultra fine grained structure in the order of 0.5-1 μm from the strain induced martensite. The final grain size was found to be an inverse function of the amount of strain induced martensite. The thermomechanical processing considerably improved the strength characteristics while the simultaneous decrease of elongation was rather low.

关键词： Austenitic stainless steel Cold rolling Ultra fine grain Deformation induced martensite

Simultaneous syngas production with different H_2/CO ratio in a multi-tubular methane steam and dry reformer by utilizing of CLC

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Journal of Energy Chemistry 2015年第1期24卷 54-64页

作者： Mohsen abbasi Mehdi Farniaei mohammad Reza Rahimpour Alireza Shariati Department of Chemical Engineering School of Chemical and Petroleum Engineering Persian Gulf UniversityBushehr 75169 Iran Department of Chemical Engineering Shiraz University of TechnologyShiraz 71555-313 Iran Department of Chemical Engineering School of Chemical and Petroleum Engineering Shiraz UniversityShiraz 71345 Iran

For syngas production, the combustion of fossil fuels produces large amounts of CO2 as a greenhouse gas annually which intensifies global warming. In this study, chemical looping combustion （CLC） has been utilized for the elimination of CO2 emission to atmosphere during simultaneous syngas production with different H2/CO ratio in steam reforming of methane （SR） and dry reforming of methane （DR） in a CLC-SR-DR configuration. In CLC-SR-DR with 184 reformer tubes （similar to an industrial scale steam reformer in Zagros Petrochemical Company, Assaluyeh, Iran）, DR reaction occurs over Rh-based catalysts in 31 tubes. Also, SR reaction is happened over Ni-based catalysts in 153 tubes. CLC via employment of Mn-based oxygen carriers supplies heat for DR and SR reactions and produces CO2 and H2O as raw materials simultaneously. A steady state heterogeneous catalytic reaction model is applied to analyze the performance and applicability of the proposed CLC-SR-DR configuration. Simulation results show that combustion efficiency reached 1 at the outlet of fuel reactor （FR）. Therefore, pure CO2 and H2O can be recycled to DR and SR sides, respectively. Also, CH4 conversion reached 0.2803 and 0.7275 at the outlet of SR and DR sides, respectively. Simulation results indicate that, 3223 kmol.h-l syngas with a H2/CO ratio equal to 9.826 was produced in SR side of CLC-SR-DR. After that, 1844 kmol.h-1 syngas with a H2/CO ratio equal to 0.986 was achieved in DR side of CLC-SR-DR. Results illustrate that by increasing the number of DR tubes to 50 tubes and considering 184 fixed total tubes in CLC-SR-DR, CH4 conversions in SR and DR sides decreased 2.69% and 3.31%, respectively. However, this subject caused total syngas production in SR and DR sides （in all of 184 tubes） enhance to 5427 kmol-h-1. Finally, thermal and molar behaviors of the proposed configuration demonstrate that CLC-SR-DR is applicable for simultaneous syngas production with high and low Hx/CO ratios in an environmental fr

关键词： chemical looping combustion (CLC) dry reforming of methane (DR) steam reforming of methane carbon dioxide capturing syngas produc-tion

Grifola frondosa polysaccharides alleviate Alzheimer's disease in rats

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Asian Pacific Journal of Tropical Biomedicine 2024年第11期14卷 500-506页

作者： Samira Behrad Sina Pourranjbar mohammad Pourranjbar Saeid abbasi-Maleki Samira Rostami Mehr Reza Hossein Gholizadeh Salmani Nasrollah Moradikor Department of Oral and Maxillofacial Pathology Dental SchoolSemnan University of Medical SciencesSemnanIran Faculty of Medicine Kerman University of Medical SciencesKermanIran Department and Neuroscience Research Center Kerman University of Medical SciencesKermanIran Pharmaceutical Sciences Research Center Health InstituteKermanshah University of Medical SciencesKermanshahIran Department of Basic Sciences Faculty of Veterinary MedicineUrmia UniversityUrmiaIran International Center for Neuroscience Research Institute for Intelligent ResearchTbilisiGeorgia

Objective:To evaluate the effect of Grifola frondosa polysaccharides(GFP)in a rat model of Alzheimer’s disease(AD).Methods:Seventy-five rats were divided into five groups:the normal control group and the AD group treated with or without GFP(100,200,and 400 mg/kg).Behavioral responses in the open field test and elevated plus maze test were ***,the levels of malondialdehyde and ferric-reducing ability of plasma,and the mRNA expressions of TNF-α,IL-6,and IL-1βin the hippocampus were ***:Treatment with GFP significantly improved AD-induced behavioral changes in the open field test and elevated plus maze test(P<0.05).In addition,the level of malondialdehyde and the mRNA expressions of TNF-α,IL-6,and IL-1βwere decreased by GFP treatment in a dose-dependent manner in AD rats(P<0.05),while the level of ferric-reducing ability of plasma was significantly increased(P<0.05).Conclusions:Oral administration of GFP can reduce inflammation and oxidative stress,as well as improve behavioral responses associated with AD,suggesting its potential use in AD ***,additional studies are needed to elucidate its underlying mechanisms and efficacy.

关键词： Grifola frondosa Polysaccharides Dementia Behavioral responses Inflammation Alzheimer’s disease