检索结果-南通市图书馆

Convective h.at transfer from two rotating circular cylinders in tandem arrangement by using lattice Boltzmann meth.d

在线全文

学校读者我要写书评

暂无评论

Applied Math.matics and Mech.nics(English.Edition) 2012年第4期33卷 427-444页

作者： h. nemati M. FARh.DI K. SEDIGh. M. M. PIROUZ N. N. ABATARI Faculty of Mech.nical Engineering Babol Noshirvani University of Technology

Th. numerical investigation of th. two-dimensional laminar flow past two ro- tating circular cylinders in th. tandem arrangement is conducted by th. lattice Boltzmann meth.d. Th. numerical strategy is used for dealing with.curved and moving boundaries of th. second-order accuracy for velocity and temperature fields. Th. effects of various rotational speed ratios and gap spacing are studied with.th. Reynolds number of 100 and th. Prandtl number of 0.71. A varied range of rotational speed ratios are investigated for four different gap spacing, i.e., 3.0, 1.5, 0.7, and 0.2. Th. results sh.w th.t, for th. first cylinder, th. lift and drag coefficients for large gap spacing are similar to th.se for a single cylinder; for th. second cylinder, th. lift coefficient descends with.th. increase in th. angular velocity for all gap spacing, wh.le th. drag coefficient ascends except for th. gap spacing of 3.0. Th. results of th. averaged periodic Nusselt number on th. surface of th. cylinders sh.w th.t, for small distances between th. cylinders and low angular velocities, conduction is a dominant mech.nism of h.at transfer, but for large distances and h.gh.angular velocities, convection is th. main mech.nism of h.at transfer.

关键词： lattice Boltzmann meth.d rotating circular cylinder laminar flow curvedand moving boundary

Titania Nanostructures for Dye-sensitized Solar Cells

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2012年第4期4卷 253-266页

作者： M.Maleksh.h. Byranvand A.nemati Kh.rat M.h.Bazargan Sch.ol of Ch.mistry University College of Science University of Tehran Iranian Research.Organization for Science and Tech.ology (IROST)

Titania is one kind of important materials, wh.ch.h.s been extensively investigated because of its unique electronic and optical properties. Research.efforts h.ve largely focused on th. optimization of th. dye,but recently th. titania nanostructures electrode itself h.s attracted more attention. It h.s been sh.wn th.t particle size, sh.pe, crystallinity, surface morph.logy, and ch.mistry of th. TiO_2 material are key parameters wh.ch.sh.uld be controlled for optimized performance of th. solar cell. Titania can be found in different sh.pe of nanostructures including mesoporous, nanotube, nanowire, and nanorod structures. Th. present article reviews th. structural, synth.sis, electronic, and optical properties of TiO_2 nanostructures for dye sensitized solar cells.

关键词： Titania nanostructures Dye sensitized solar cells Mesoporous Nanotubes Nanowires Nanorods

Zn(NO_3)_2·6h.2O/2,4,6-trich.oro-1,3,5-triazine(TCT) a mild and selective system for nitration of ph.nols

在线全文

学校读者我要写书评

暂无评论

Ch.nese Ch.mical Letters 2010年第4期21卷 403-406页

作者： Firouzeh.nemati h.ssein Kiani Department of Ch.mistry Faculty of ScienceSemnan UniversitySemnanIran

Certain ph.nols and naph.h.ls were nitrated regioselectively with.Zn(NO)·6h./TCT in acetonitrile as solvent at room temperature and sh.rt reaction time in good *** reaction condition was *** is a ch.ap and commercial... 详细信息

关键词： Nitration Ph.nols 2 4 6-Trich.oro-l 3 5-triazine Regioselective

Nano-Fe_3O_4 encapsulated-silica particles bearing sulfonic acid groups as a magnetically separable catalyst for green and efficient synth.sis of functionalized pyrimido[4,5-b]quinolines and indeno fused pyrido[2,3-d]pyrimidines in water

在线全文

学校读者我要写书评

暂无评论

Ch.nese Ch.mical Letters 2013年第5期24卷 370-372页

作者： Firouzeh.nemati Rah.leh.Saeedirad Department of Ch.mistry Semnan University

Th. magnetic nanoparticles supported silica sulfuric acid was used as an efficient catalyst for th. synth.sis of pyrimido[4,5-b]quinoIines and indeno fused pyrido（2,3-d]pyrimidines in *** desired products were obtained in excellent ***_3O_4@SiO_2-SO_3h.was readily recovered using an external magnet and could be reused several times with.ut significant loss of reactivity.

关键词： Magnetic nanoparticles Pyrimido[4,5-b]quinolines Indeno fused pyrido[2,3-d]pyrimidines Green solvent

Synth.sis and spectral properties of Nd-doped glass-ceramics in SiO_2-CaO-MgO system prepared by sol-gel meth.d

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earth. 2013年第6期31卷 595-599页

作者： Masoud Eslami Zoh.eh.h.mnabard Ali nemati Materials Science & Engineering Department Sharif University of Technology Materials Research.Sch.ol Ceramic Group

SiO2-CaO-MgO glass and glass-ceramic powder doped with.Nd3＋ were synth.sized with.sol-gel meth.d. Tetraeth.lorth.silicate （TEOS）, Ca（NO3）2？4h.O, Mg（NO3）2？6h.O, Nd（NO3）3？6h.O, eth.nol, distilled water, and h.O3 were used as starting materials. Th. synth.sized powder’s properties were examined with.simultaneous th.rmal analysis （STA）, X-ray diffraction （XRD）, ph.toluminescence （PL） and scanning electron microscopy （SEM） analysis. Th. STA curves sh.wed th.t th. softening point and crystallization temperatures were sh.fted to h.gh.r temperatures with.increasing dopant content. Regarding XRD patterns of glass samples, Nd was found to act as an intermediate oxide in glass matrix. Th. XRD patterns of glass-ceramic samples indicated th.t bredigite and akermanite crystallized in th. glass matrix after h.at treating at 900 oC. Th. fluorescence spectra sh.wed th.t glass-ceramics emitted much.stronger irradiation th.n glasses with.th. same dopant content. Th. SEM images illustrated uniform and h.mogeneous distribution of applied oxides in glass and glass-ceramic compositions.

关键词： glass glass-ceramic synth.sis sol-gel meth.d spectral properties rare earth.

Improvements in th. microstructure and fatigue beh.vior of pure copper using equal ch.nnel angular extrusion

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2014年第6期21卷 569-576页

作者： J.nemati G.h.Majzoobi S.Sulaiman B.T.h.T.Bah.rudin M.A.Azmah.h.nim Department of Mech.nical and Manufacturing Engineering Universiti Putra Malaysia Sch.ol of Mech.nics Islamic Azad UniversityTakestan Branch348194 9479 Takestan Iran

In th.s study, annealed pure copper was extruded using equal ch.nnel angular extrusion （ECAE） for a maximum of eigh. passes. Th. fatigue resistance of extruded specimens was evaluated for different passes and applied stresses using fatigue tests, fractograph., and metallograph.. Th. mech.nical properties of th. extruded material were obtained at a tensile test velocity of 0.5 mm/min. It was found th.t th. maximum increase in strength.occurred after th. 2nd pass. Th. total increase in ultimate strength.after eigh. passes was 94%. Th. results of fatigue tests indicated th.t a significant improvement in fatigue life occurred after th. 2nd pass. In subsequent passes, th. fatigue life con-tinued to improve but at a considerably lower rate. Th. improved fatigue life was dependent on th. number of passes and applied stresses. For low stresses （or h.gh.cycle fatigue）, a maximum increase in fatigue resistance of approximately 500%was observed for th. extruded material after eigh. passes, wh.reas a maximum fatigue resistance of 5000%was obtained for h.gh.applied stresses （or low-cycle fatigue）. Optical microscopic examinations revealed grain refinements in th. range of 32 to 4 μm. A maximum increase in impact energy absorption of 100%was ach.eved after eigh. passes. Consistent results were obtained from fractograph. and metallograph. examinations of th. ex-truded material during fatigue tests.

关键词： copper equal ch.nnel angular extrusion fatigue of materials grain size grain refinement fracture tough.ess

Effect of equal ch.nnel angular extrusion on Al-6063 bending fatigue ch.racteristics

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2015年第4期22卷 395-404页

作者： J.nemati G.h.Majzoobi S.Sulaiman B.T.h.T.Bah.rudin M.A.Azmah.h.nim Department of Mech.nical and Manufacturing Engineering University Putra Malaysia Engineering Faculty Bu-Ali Sina University Sch.ol of Mech.nics Islamic Azad UniversityTakestan Branch

Th. purpose of th.s investigation was to refine th. grains of annealed 6063 aluminum alloy and to improve its yield stress and ul- timate strength. Th.s was accomplish.d via th. equal ch.nnel angular extrusion （ECAE） process at a temperature of 200℃ using route A, with.a constant ram speed of 30 mm/min th.ough.a die angle of 90° between th. die ch.nnels for as many as 6 passes. Th. experiments were conducted on an Avery universal testing mach.ne. Th. results sh.wed th.t th. grain diameter decreased from 45 μm to 2.8 μm after 6 extru- sion passes. Th. results also indicated th.t th. major improvement in fatigue resistance occurred after th. first pass. Th. subsequent passes improved th. fatigue life but at a considerably lower rate. A maximum increase of 1100% in th. case of low applied stresses and an ap- proximately 2200% increase in fatigue resistance in th. case of h.gh.applied stresses were observed after 5 passes. Th. improvement of fa- tigue resistance is presumed to be due to （1） a reduction in th. size and th. number of Si crystals with.increasing number of ECAE passes, （2） th. aggregation of Cu during th. ECAE process, （3） th. formation and growth.of CuA12 grains, and （4） grain refinement of th. A1--6063 alloy during th. ECAE process.

关键词： aluminum alloys equal ch.nnel angular pressing bending fatigue life grain size microstructure

h.at transfer simulation of annular elliptical fin-and-tube h.at exch.nger by transition SST model

在线全文

学校读者我要写书评

暂无评论

Journal of Central South.University 2020年第8期27卷 2324-2337页

作者： h.nemati A R RAh.MZADEh.WANG Ch.-ch.an Department of Mech.nics Marvdasht BranchIslamic Azad UniversityMarvdashtIran Mech.nical Engineering Islamic Azad UniversityBushehr branchBushehrIran Department of Mech.nical Engineering National Chiao Tung UniversityHsinchu 300TaiwanChina

In th.s study,th.rmo-fluid ch.racteristics of elliptical annular finned tube h.at exch.nger were numerically studied in *** SST model was utilized to simulate turbulent *** of air velocities,h.rizontal to vertical fin diameter ratios,and fin densities were examined in *** simulations indicate superior performance of elliptical fin *** was sh.wn th.t pressure drop of annular elliptical fin can be only one h.lf of th.t of a circular annular fin wh.le containing comparable h.at transfer *** vertical elliptical annular fin may even contain a h.gh.r h.at transfer performance over circular *** are proposed to estimate th. Nu number and pressure drop based on th. annular circular *** maximum deviations between th. proposed correlations and simulations regarding pressure drop and h.at transfer coefficient are 5.6%and 3.2%,*** furth.r elaboration of th. superiority of th. elliptical layout from th. second law perspective,normalized entropy generation was also *** all cases,th. entropy generation rate in circular fin was h.gh.r th.n th.t of an elliptical fin.

关键词： annular fin elliptical fin entropy generation transition SST model tube bundle

Multi Objective Load Sh.dding Framework

在线全文

学校读者我要写书评

暂无评论

Smart Grid and Renewable Energy 2015年第8期6卷 260-277页

作者： Atieh.Delavari Milad nemati Moh.mmad h. Moradi Power System Engineering HamedanIran Ph.tovoltaic Systems Power Engineering HamedanIran Microgrids Control Power Engineering HamedanIran

In th.s paper, a multi-objective load sh.dding framework on th. power system is presented. Th. frame work is useable in any kind of smart power systems;th. word of smart h.re refers to th. availability of data transmission infrastructure (like PLC or power line carrier) in th. system, in order to carry th. system data to th. load sh.dding framework. Th.s is an open framework th.t means it can optimize load sh.dding problem by considering unlimited number of objective functions, in oth.r word, th. number of objectives can be as much.as th. operator decides, finally in th. end of frame work just one matrix breaker state is ch.sen in a way of h.ving th. most compatibility with.th. operator ideas wh.ch.are determined by objectives importance percentage wh.ch.are one input groups of th. framework. A two-stage meth.dology is used for th. optimal load sh.dding problem. In th. first stage, Discrete Multi-objective Particle Swarm Optimization meth.d is used to find a collection of th. best states of load sh.dding (Pareto front). In th. second stage, th. fuzzy logic is used as a Pareto front inference engine. Fuzzy selection algorith. (FSA) is designed in a way th.t it can infer according to th. operator’s opinion with.ut th. expert interference th.t means rule base is formed automatically by fuzzy algorith.. FSA is consisted of two parts. Membersh.p functions and rules base are formed automatically in th. first part, th. former in accordance with.th. costs of Pareto front particles and th. latter in correspondence with.importance percentage of objectives wh.ch.are entered to FSA by operator;in oth.r word, decision matrix is formed automatically in th. algorith. according to th. cost of Pareto front particles and importance percentage of objectives. In th. Second part, Mamdani inference engine scrutinizes th. Pareto front particles by th. use of formed membersh.p functions and rules base to know if th.y are compatible to operator’s opinion or not. Getting th.s approach. cost

关键词： Objective Load Sh.dding Pareto Front Fuzzy