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Propulsion and Power Research 2020年第4期9卷 355-371页

作者： Alborz Zehni Navid Balazadeh mojtaba Hajibabaei Kamran Poorghasemi Engine Research Center Mega Motor CorpTehranIran Department of Mechanical Engineering Sharif University of TechnologyTehranIran Department of Mechanical Engineering Iran University of Science and TechnologyTehranIran Department of Mechanical Engineering Shabestar BranchIslamic Azad UniversityShabestarIran

New methods have been studied in the past few decades to decrease exhaust emissions and fuel consumption of diesel *** new combustion methods as low-temperature combustion(LTC)strategies and also utilizing new fuels as bio-diesel are beneficial ways to overcome diesel engine *** numerical study focused on the effect of split injection strategies as well as swirl ratio(SR)on the biodiesel premixed charge compression ignition(PCCI)combustion process and the related *** this regard,KIVA-3V code as a CFD tool has been utilized to analyze the combustion and emission characteristics of the diesel *** and split injection strategies have been executed on biodiesel PCCI combustion and have been compared in order to probe and examine the injection *** results show that in both strategies,advancing the injection timing can lower the combustion emission and improve the engine performance by optimizing the start of injection(SOI)as sweet spot *** a high swirl ratio with the split injection strategy has a negative effect on overall combustion,emission,and performance in comparison with the single injection *** multi-injection scheme,SOI=−35 ATDC,SR=1.1,and for single injection scheme,SOI=−40 ATDC,SR=1.1 are considered as optimum cases regarding minimum total exhaust emissions and highest performance.

关键词： Premixed charge compression ignition(PCCI) Split injection Swirl ratio Biodiesel Combustion Emission

An empirical analysis of effective factors on farmers adaptation behavior in water scarcity conditions in rural communities

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International Soil and Water Conservation Research 2017年第4期5卷 265-272页

作者： Abdolmotalleb Rezaei Morteza Salmani Fatemeh Razaghi mojtaba Keshavarz Department of Agricultural Extension and Education College of Agricultural Economics and DevelopmentUniversity of TehranKarajIran

This paper investigates the effect of factors on Farmers Adaptation Behavior in Water Scarcity Conditions in Rural Communities of Sabzevar,Iran.A survey questionnaire was used for collecting data,the study population was 120 farmers in rural Sabzevar County selected based on the Cochran formula.A questionnaire was designed for the target group for the measurement of on farm adaptation behavior in water scarcity *** models were drawn using structural equation modeling and the relationships between latent variables and *** findings indicate that there is a significant relationship between awareness and adaptation ***,there is a significant relationship among network and media on farmer's perception about water scarcity and their activities toward better management of water in the critical *** are also significant relationships among perception and awareness with intention however,intention do not effect on adaptation behavior *** other words,even the that means farmers had information about crisis,they are not able to have not operational plans to confront the water scarcity conditions.

关键词： Farmers adaptation behavior Water scarcity Rural communities Iran

Use of GIS and BIM for the integration of tunnel designand construction process in conventional tunneling

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Underground Space 2024年第3期16卷 261-278页

作者： Mansour Hedayatzadeh Jamal Rostami Vasilis Sarhosis mojtaba Nematollahi Nabiollah Hajiantilaki Abouzar Shafiepour University of Leeds Leeds LS29JTUK Colorado School of Mines GoldenCO 80401USA University of Minho Guimaraes 4800-058Portugal General Mechanic Company Tehran ***Iran Ettehadrah Consulting Engineers Tehran Q83GVWVIran

This paper presents the development of a framework for the parametric design of tunnels using geographic information system (GIS)mapping and building information modelling (BIM). According to the framework, a parametric representation of each system component (e.g., layers of rock mass, size of excavation, topography, fault geometry, primary lining, secondary lining, rock bolts, etc.) can beincorporated in the GIS model with high levels of detail and used for the automatic generation of numerical models for the design oftunnel construction. This parametric evaluation allows the designer to consider several levels of detail for each component, for the effi-cient design and process optimization in conventional tunneling. Information between parametric analysis and numerical simulations canbe freely exchanged with significantly reduced computational effort while results can be exported into BIM. It is anticipated that the proposed framework could lead to a comprehensive, yet efficient analysis of complex conventional tunneling project using parametric evaluations at the early design stages.

关键词： Geographic information system Building information modelling Conventional tunneling Numerical simulations Parametric analysis

An Efficient Four-component Synthesis of Spiro[indolinepyrazolo[4＇,3＇：5,6] pyrido[2,3-d] pyrimidine]triones

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Chinese Journal of Chemistry 2012年第2期30卷 321-326页

作者： Ghahremanzadeh,Ramin Moghaddam,mojtaba Mirhosseini Bazgir,Ayoob Akhondi,Mohammad Mehdi Nanobiotechnology Research Center Avicenna Research InstituteACECRTehranIran Department of Chemistry Shahid Beheshti UniversityG.C.P.O.Box 19396-4716TehranIran Reproductive Research Center Avicenna Research InstituteACECRTehranIran

A four-component reaction in the presence of Alum [KAl（SO4）2·12H2O] as an inexpensive and reusable catalyst using the ionic liquid as an effective green reaction media is reported.

关键词： catalysis condensation cyclization green chemistry ionic liquids multicomponent reaction spiro compounds

Synthesis of 2-Aryl-l-arylmethyl-lH-1,3-benzimidazole Derivatives Using Silica-bonded PropyI-S-sulfonic Acid as Recyclable Solid Acid Catalyst

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Chinese Journal of Chemistry 2012年第3期30卷 517-521页

作者： Ghaem Ahmadi-Ana,Sayed Mohammad Baghernejad,mojtaba Niknam,Khodabakhsh Chemistry Department Gachsaran BranchIslamic Azad UniversityGachsaranIran Chemistry Department Faculty of SciencesPersian Gulf UniversityBushehr75169Iran

A highly selective synthesis of 2-aryl-l-arylmethyl-lH-1,3-benzimidazoles from the reaction of o-phenylene- diamine and aromatic aldehydes in the presence of silica-bonded propyl-S-sulfonic acid （SBSSA） at 80℃ in w... 详细信息

关键词： silica-bonded propyl-S-sulfonic acid aldehydes 2-aryl- 1-arylmethyl-lH-1,3-benzimidazoles,o-phenylenediamine water

Experimental study of ice accretion effects on aerodynamic performance of an NACA 23012 airfoil

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Chinese Journal of Aeronautics 2016年第3期29卷 585-595页

作者： Sohrab Gholamhosein Pouryoussefi Masoud Mirzaei Mohammad-Mahdi Nazemi mojtaba Fouladi Alireza Doostmahmoudi Department of Aerospace Engineering K.N.Toosi University of Technology

In this paper, the effects of icing on an NACA 23012 airfoil have been studied. Exper- iments were applied on the clean airfoil, runback ice, horn ice, and spanwise ridge ice at a Reynolds number of 0.6 x 10^6 over angles of attack from -8° to 20% and then results are compared. Gener- ally, it is found that ice accretion on the airfoil can contribute to formation of a flow separation bubble on the upper surface downstream from the leading edge. In addition, it is made clear that spanwise ridge ice provides the greatest negative effect on the aerodynamic performance of the airfoil. In this case, the stall angle drops about 10^6 and the maximum lift coefficient reduces about 50% which is hazardous for an airplane. While horn ice leads to a stall angle drop of about 4°and a maximum lift coefficient reduction to 21%, runback ice has the least effect on the flow pattern around the airfoil and the aerodynamic coefficients so as the stall angle decreases 2% and the maximum lift reduces about 8%.

关键词： Airfoil icing Aviation accidents:Horn ice NACA 23012 airfoilRunback ice Separation bobble Spanwise ridge ice

Alum （KAI（SO4）2·12H2O） Catalyzed Multicomponent Transformation： Simple, Efficient, and Green Route to Synthesis of Functional- ized Spiro[chromeno[2,3-d]pyrimidine-5,3＇-indoline]-tetraones in Ionic Liquid Media

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Chinese Journal of Chemistry 2012年第3期30卷 709-714页

作者： Mirhosseini Moghaddam, mojtaba Bazgir, Ayoob Mohammad Mehdi, Akhondi Ghahremanzadeh, Ramin Nanobiotechnology Research Center Avicenna Research Institute ACECR Tehran Iran Department of Chemistry Shahid Beheshti University Tehran Iran Reproductive Research Center Avicenna Research Institute ACECR Tehran Iran

The combination of isatin, barbituric acid, and cyclohexane-1,3-dione derivatives in the presence of alum （KAI（SO4）2· 12H2O） as a catalyst for 15 min was found to be a suitable and efficient method for the synthe... 详细信息

关键词： isatin spirooxindoles dimedone barbituric acid ionic liquids

Recent progress and perspectives in additive manufacturing of magnesium alloys

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Journal of Magnesium and Alloys 2022年第6期10卷 1511-1541页

作者： Zhuoran Zeng mojtaba Salehi Alexander Kopp Shiwei Xu Marco Esmaily Nick Birbilis College of Engineering and Computer Science Australian National UniversityACT.2601 Australia Additive Manufacturing Group Singapore Institute of Manufacturing Technology(SIMTech)Agency forScienceTechnology and Research(A∗STAR)73 Nanyang Drive637662 Singapore Meotec GmbH Philipsstr.8AachenGermany State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan UniversityChangsh1410082 China Department of Materials Science and Engineering Massachusetts Institute of TechnologyCambridgeMA 02139United States of America Volvo Materials Technology Laboratory Volvo GroupLundbyGothenburg 41715Sweden

Magnesium alloys remain critical in the context of light-weighting and advanced devices. The increased utilisation of magnesium(Mg)each year reveals growing demand for its Mg-based alloys. Additive manufacturing(AM) provides the possibility to directly manufacture components in net-shape, providing new possibilities and applications for the use of Mg-alloys, and new prospects in the utilisation of novel physical structures made possible from ‘3D printing’. The review herein seeks to holistically explore the additive manufacturing of Mg-alloys to date, including a synopsis of processes used and properties measured(with a comparison to conventionally prepared Mg-alloys). The challenges and possibilities of AM Mg-alloys are critically elaborated for the field of mechanical metallurgy.

关键词： Magnesium Additive manufacturing Microstructure 3D printing Mechanical properties Electrochemical properties

Analysis of Turbulent Flow on Tidal Stream Turbine by RANS and BEM

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Computer Modeling in Engineering & Sciences 2021年第5期127卷 515-532页

作者： Younes Noorollahi Mohammad-Javad Ziabakhsh Ganji Mohammadmahdi Rezaei mojtaba Tahani Department of Renewable Energy and Environmental Engineering Faculty of New Sciences and TechnologiesUniversity of TehranTehran***Iran Energy Modelling and Sustainable Energy System(METSAP)Research Laboratory Faculty of New Sciences and TechnologiesUniversity of TehranTehran***Iran Department of Aerospace Engineering Faculty of New Sciences and TechnologiesUniversity of TehranTehran***Iran

Nowadays,concerns arise because of the depletion of fossil fuel resources that forced scientists to develop new energy extraction *** of these renewable resources is tidal energy,where Iran has this potential *** are many ways to obtain the kinetic energy of the fluid flow caused by the moon’s gravitational effect on *** horizontal axis tidal turbines is one of the ways to achieve the kinetic energy of the *** this type of turbine has similar technology to horizontal axis wind turbines,they may be an appropriate choice for constructing a tidal power plant in *** paper presents the numerical simulation and momentum method of a three-bladed horizontal axis tidal *** validate the thrust and power coefficients for a fixed pitch angle at the blade tip speed ratio of 4 to 10 are compared with experimental *** this modelling,the rotating geometry simulation has been *** show that using a numerical method and blade element momentum,we can predict the horizontal axis tidal turbine’s thrust with an error of less than 10%.The numerical method has better accuracy in higher speed ratios,and it is appropriate to predict the behaviour of fluid in collision with turbines and its wake effects.

关键词： CFD BEM slicing mesh tidal stream turbine TSR

Innovative Compensation Methods for Large Voltage Drop Effects in Very Long HVDC Transmission Systems

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CSEE Journal of Power and Energy Systems 2021年第1期7卷 1-8页

作者： mojtaba Mohaddes Ting An Jingjing Lu Narinder Dhaliwal Marcio Szechtman Bjarne R.Andersen TransGrid Solutions.Winnipeg Canada Global Energy Interconnection Research Institute SGCC.Beijing 102209China Electrobras Rio de JaneiroBrazil Anderson Power Electronic Solutions Ltd Bexhill on SeaUK

This paper discusses the impacts of large voltage drops on very long HVDC transmission lines,especially when operating in a monopolar *** effect of using dedicated metallic return(DMR)conductors is *** main focus is on the potential rise at the neutral point of the converters and the need for an increased range for the converter transformer tap *** grounding schemes for multiterminals transnational HVDC systems are presented:single point low impedance grounding and high impedance multi-point *** advantages of the high impedance scheme are *** innovative compensation method for voltage drop effects using a series HVDC converter is presented along with simulation *** novel series converter can address both issues of neutral voltage rise and the impractical tap changer *** put the ideas into the perspective,a realistic example of a transnational HVDC connecting China,central Asia,Russia and West Europe is presented.

关键词： DC grid grounding HVDC series compensation transnational HVDC