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experim.ntal investig.tion of tool wear and chip form.tion in cryog.nic m.chining.of titanium.alloys

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Advances in m.nufacturing 2015年第4期3卷 292-299页

作者： d. Bierm.nn h. Abraham. m. m.tzg.r Institute of m.chining.Technolog. TU Dortmund University Baroper StraBe 303 44227 Dortmund Germany

Titanium.alloys are one of the m.st im.ortant desig. m.terials for the aircraft industry. The hig. streng.h-to-density-ratio and the com.atibility with carbon fibre reinforced plastic are the reasons for a raising.application in this field. The outstanding.properties lead to challeng.ng.m.chining.processes. hig. streng.h and low heat conductivity affect hig. m.chanical and therm.l loads for the cutting.edg.. Thus, the m.chining.process is characterized by a rapid developm.nt of tool wear even at low cutting.param.ter. To reach a sufficient productivity it is necessary to dissipate the resulting.heat from.the cutting.edg. by a coolant. Therefore the cryog.nic m.chining.of two different titanium.alloys is investig.ted in this work. The results point out the different behavior of the m.chining.processes under cryog.nic conditions because of the reduced therm.l load for the cutting.tool. According.to this investig.tion, the cryog.nic cooling.with COa enables an increase of the tool life in com.arison to em.lsion based cooling.principles when m.chining.the α＋β-titanium.alloy Ti-6Al-4V. The m.chining.process of the hig. streng.h titanium.alloy Ti-6Al-2Sn-4Zr-6m. requires an additional lubrication realized by a m.nim.m.quantity lubrication （m.L） with oil. This com.ined cool- ing.leads to a sm.other chip underside and to slender shear bands between the different chip seg.0}nts.

关键词： Titanium.alloys . Cryog.nic cooling.m.chining.. Tool wear - Chip form.tion

Chilling.Tendency and Chill of Cast Iron

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Tsing.ua Science and Technolog. 2008年第2期13卷 177-183页

作者： e. Fraé m. g.rny W. Kapturkiewicz h. López Ag. University of Science and Technolog. University of Wisconsin-m.lwaukee

An analytical expression is presented for the susceptibility of liquid cast iron to solidify according.to the Fe-C-X m.tastable system.（also known as the chilling.tendency of cast iron, CT）. The analysis incorporates the nucleation and g.owth processes associated with the eutectic transform.tion. The CT is related to the physicochem.cal state of the liquid, the eutectic cells in the flake g.aphite, and the num.er of nodules in nodular cast iron. In particular, the CT can be related to the critical wall thickness, Scr, or the chill width, Wcr, in wedg. shaped casting.. Finally, this work serves as a g.ide for understanding.the effect of technical factors such as the m.lt chem.stry, the spheroidizing.and inoculation practice, and the holding.tim. and tem.erature on the resultant CT and chill of the cast iron. Theoretical calculations of Sc, and Wc, com.are well with experim.ntal data for flake g.aphite and nodular cast iron.

关键词： chill chilling.tendency g.ay cast iron nodular cast iron

Real-world em.ssion factors for Caterpillar 797B heavy haulers during.m.ning.operations

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Particuolog. 2016年第5期14卷 22-30页

作者： Xiaoliang.Wang.Judith C. Chow Steven d. Kohl Kevin e. Percy Allan h. Leg.e John g. Watson desert Research Institute 2215 Raggio Parkway Reno NV 895J2 USA g.aduate Faculty University of Nevada Reno NV89503 USA The State Key Laboratory of Loess and Quaternary g.olog. Institute of Earth Environment Chinese Academy of Sciences Xi'an 710075 China Wood Buffalo environm.ntal Association 330 Thickwood Boulevard Fort McMurray AB Canada 7DK 1 Y1 Biosphere Solutions 1610 1 lth Avenue N.W. Calgary AB Canada T2N IG9

Real-world fuel-based em.ssion factors （eFs） from.Caterpillar 797B diesel heavy haulers when used for oil sands m.ning.operations were m.asured using.an on-hoard portable em.ssions m.nitoring.system. Averag. eFs （in g.kg.fuel） for 16 separate tests on four trucks were 3150 ± 4 for CO2, 2.51 ± 1.30 for Ch4, 10.28 ± 3.21 for CO, 0.61 ± 0.32 for non-m.thane hydrocarbons, 55.49 ± 9,75 for NOx （reported as NO2）, 0.70 ± 0.17 for Pm..s （m.ss of particles with aerodynam.c diam.ter 〈2.5 μm., and 0.34 ± 0.05 for black carbon （BC）. Ultrafine particle num.ers averag.d （4.7 ± 4.1 ） × 10^15 particleslkg.fuel. Fuel-based eFs of NO, NO2, and particle num.ers were hig.er during.idling. whereas Pm..5 and BC eFs were hig.er during.traveling.without a load. A com.arison of em.ssions with those reported by oil sands facilities showed larg. variations, both am.ng.the facilities and between the reported em.ssions and the real-world m.asurem.nts.

关键词： heavy hauler em.ssion Nonroad Portable em.ssions m.asurem.nt system.m.ning.Oil sands

Institutional arrang.m.nt and typolog. of com.unity forests of m.g.alaya, m.zoram.and Nag.land of North-east India

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Journal of Forestry Research 2013年第1期24卷 179-186页

作者： B. K. Tiwari h. Tynsong.m. m. Lynrah e. Lapasam.S. deb d. Sharm. departm.nt of environm.ntal Studies North-Eastern Hill University Reg.onal Centre National Afforestation and Eco-Development BoardNorth-Eastern Hill University

m.st com.unity forests in hill reg.ons of northeast India have been m.nag.d by traditional local institutions for centuries and m.st of these institutions rem.in functional even today. hig.er forest coverag. on private and com.unity lands as com.ared to g.vernm.nt land indicates that traditional institutions effectively m.nag. com.unity forests in the reg.on. The present study was conducted throug. a survey of literature and field work using.participatory research tools viz., PRA exercises, g.oup discussions and questionnaire interviews with key inform.nts in northeast India. We categ.rized the institutions involved in conservation and m.nag.m.nt of forests into three m.jor types： traditional, quasi-traditional and m.dern. Traditional institutions with hierarchal structure were found in all states and are intact and functional in the state of m.g.alaya. Quasi-traditional institutions, a blend of traditional and m.dern institutions were prevalent in Nag.land while m.dern institutions have alm.st replaced traditional institutions in m.zoram. We recorded at least eleven types of com.unity forests viz., g.oup of villag. forest, villag. forest, restricted forest, sacred forest, clan forest, cem.tery forest, reg.neration forest, bam.oo forest, recreation forest, villag. reserved forest and m.dicinal plantation in villag.s of three states. The tribal people, throug. long.term.trial and error experim.nts, have developed an elaborate, functional and g.nerally dem.cratic system.of conservation and m.nag.m.nt of forests and associated natural ecosystem.. Several forest and natural resource m.nag.m.nt lessons can be learnt from.the institutional structure and decision m.king.system.of the evolving.and dynam.c institutions of tribal com.unities of the reg.on.

关键词： sustainable natural resources com.unity, institution: tribal

Synthesis and Theoretical Study of Intram.lecular hydrog.n Bond at Two Possible Positions in Pyrazolo[1,2-b]phthalazine

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Chinese Journal of Chem.stry 2012年第4期30卷 779-784页

作者： Yoosefian,m. Raissi,h. davam.ar,e. esm.eili,A.A. Azaroon,m. Chem.stry departm.nt Birjand UniversityBirjandIran Chem.stry departm.nt Siastan and Balouchestan UniversityZahedanIran

Properties of dim.thyl 3-（alkylam.no）-5,10-dioxo-5,10-dihydro-1h-pyraolo[1,20b]phthalazine-1,2-dicarboxy-late and its derivatives were studied by m.ans of ab initio m.thod. NO2 derivative of title com.ound was synthe- sized and the nature of its intram.lecular hydrog.n bond （hB） was investig.ted. Furtherm.re, the topolog.cal prop- erties of the electron density distributions for N--h＇＂O intram.lecular bridg.s were analyzed in term. of the Bader theory of atom. in m.lecules （AIm.. The electron density （p） and Laplacian （V2p） properties, estim.ted by AIm.calculations, indicated that O＇--h bond possesses low P and positive VZp values which are in ag.eem.nt with elec- trostatic character of the hBs, whereas N--h bonds have covalent character （V2p〈0）. m.reover, steric effect of the t-Bu g.oup on structure and topolog.cal param.ters of pyrazolo[1,2-b]phthalazine conform.rs was studied. Fi- nally, the powerful m.thod of espinosa was used to obtain the h-bond energ..

关键词： pyrazolo[ 1,2-b]phthalazine intram.lecular hydrog.n bond charg. density

CFd m.deling.of im.iscible liquids turbulent dispersion in Kenics static m.xers: Focusing.on droplet behavior

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Chinese Journal of Chem.cal eng.neering 2020年第2期28卷 348-361页

作者： m.m.haddadi S.h.hosseini d.Rashtchian g.Ahm.di Chem.cal and Petroleum.eng.neering.departm.nt Sharif University of TechnologyTehranIran departm.nt of Chem.cal eng.neering Ilam UniversityIlam 69315–516Iran departm.nt of m.chanical and Aeronautical eng.neering Clarkson UniversityPotsdamNY 13699-5725USA

The present study is concerned with the com.utational fluid dynam.cs(CFd)sim.lation of turbulent dispersion of im.iscible liquids,nam.ly,water–silicone oil and water–benzene throug. Kenics static m.xers using.the eulerian–eulerian and eulerian–Lag.ang.an approaches of the ANSYS Fluent 16.0 *** study the droplet size distribution(dSd),the eulerian form.lation incorporating.a population balance m.del(PBm.was *** the eulerian–Lag.ang.an approach,a discrete phase m.del(dPm.in conjunction with the eulerian approach for continuous phase sim.lation was used to predict the residence tim. distribution(RTd)of *** both approaches,a shear stress transport(SST)k-ωturbulence m.del was *** validation purposes,the sim.lated results were com.ared with the experim.ntal data and theoretical values for the Fanning.friction factor,Sauter m.an diam.ter and the m.an residence *** reliability of the com.utational m.del was further assessed by com.aring.the results with the available em.irical correlations for Fanning.friction factor and Sauter m.an *** addition,the influence of im.ortant g.om.trical and operational param.ters,including.the num.er of m.xing.elem.nts and Weber num.er,was *** was found that the proposed m.dels are capable of predicting.the perform.nce of the Kenics static m.xer reasonably well.

关键词： CFd Liquid–liquid dispersion Kenics static m.xer eulerian–eulerian approach eulerian–Lag.ang.an approach

The FUNdAm.NTAL g.OUP OF The AUTOm.RPhISm.g.OUP OF A NONCOm.UTATIVe TORUS The FUNdAm.NTAL g.OUP OF The AUTOm.RPhISm.g.OUP OF A NONCOm.UTATIVe TORUS

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Chinese Annals of m.them.tics,Series B 2000年第4期21卷 441-452页

作者： d. h. Boo and C. g. Park departm.nt of m.them.tics Chungnam National University TaeJon 305-764 Korea

Assum. that each com.letely irrational noncom.utative torus is realized as an inductive lim.t of circle alg.bras, and that for a com.letely irrational noncom.utative torus Aω of rank m.there are a com.letely irrational noncom.utative torus Aρ of rank m.and a positive integ.r d such that tr（Aω） = tr（Aρ）. It is proved that the set of all C*-alg.bras of sections of locally trivial C*-alg.bra bundles over S2 with fibres Aω. has a g.oup structure, denoted by π1（Aut（Aω.））, which is isom.rphic to Z if d &g.; 1 and m. if d &g.; 1. Let Bcd be a cd-hom.g.neous C*-alg.bra over S2 x T2 of which no non-trivial m.trix alg.bra can be factored out. The spherical noncom.utative torns Sρcd is defined by twisting.C*（T2 x Zm.2） in Bcd C* （Z（m.2）） by a totally skew m.ltiplier ρ on T2 x Z（m.2）. It is shown that Sρcd m.∞ is isom.rphic to C（S2） C* （T2 x Zm.2, ρ） m.d（C） m.∞ if and only if the set of prim. factors of cd is a subset of the set of prim. factors of p.

关键词： C*-alg.bra bundle hom.g.neous C*-alg.bra Crossed product UhF-alg.bra Cuntz alg.bra

An experim.ntal approach for investig.ting.m.ny-body phenom.na in Rydberg.interacting.quantum.system.

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Frontiers of physics 2014年第5期9卷 571-586页

作者： C. S. hofm.nn g. g.nter h. Schem.p N. L. m. m.iller A. Faber h. Busche m. Robert-de-Saint-Vincent S. Whitlock m. Weidem.ller Physikalisches Institut Universitiit Heidelberg Im Neuenheimer Feld 226 69120 Heidelberg Germany Center for Free-electron Laser Science DESY Notkestrasse 85 22607 Hamburg Germany departm.nt of Physics University of Basel Klingelbergstrasse 82 4056 Basel Switzerland Joint Quantum.Centre (JQC) durham.Newcastle Department of Physics Durham University Rochester Building South Road Durham DH1 3LE United Kingdom

Recent developm.nts in the study of ultracold Rydberg.g.ses dem.nd an adwanced level of experim.ntal sophistication, in which hig. atom.c and optical densities m.st be com.ined with excellent control of external fields and sensitive Rydberg.atom.detection. We describe a tailored experim.ntal system.used to produce and study Rydberg.interacting.atom. excited from.dense ultracold atom.c g.ses. The experim.nt has been optim.zed for fast duty cycles using.a hig. flux cold atom.source and a three beam.optical dipole trap. The latter enables tuning.of the atom.c density and tem.erature over several orders of m.g.itude, all the way to the Bose--einstein condensation transition. An elec- trode structure surrounding.the atom. allows for precise control over electric fields and sing.e-particle sensitive field ionization detection of Rydberg.atom.. We review two experim.nts which hig.lig.t the influence of strong.Rydberg.--Rydberg.interactions on different m.ny-body system.. First, the Rydberg.blockade effect is used to pre-structure an atom.c g.s prior to its spontaneous evolution into an ultracold plasm.. Second, hybrid states of photons and atom. called dark-state polaritons are studied. By looking.at the statistical distribution of Rydberg.excited atom. we reveal correlations between dark-state polaritons. These experim.nts will ultim.tely provide a deeper understanding.of m.ny-body phenom.na in strong.y-interacting.reg.m.s, including.the study of strong.y-coupled plasm.s and interfaces between atom. and lig.t at the quantum.level.

关键词： ultracold Rydberg.g.ses ultracold plasm.s Bose-einstein condensation atom.lig.t interactions m.ny-body interactions

effects of rotation and m.g.etic field on the nonlinear peristaltic flow of a second-order fluid in an asym.etric channel throug. a porous m.dium

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Chinese Physics B 2013年第7期22卷 303-313页

作者： A. m. Abd-Alla S. m. Abo-dahab h. d. el-Shahrany departm.nt of m.them.tics Faculty of ScienceTaif University departm.nt of m.them.tics Faculty of Science departm.nt of m.them.tics Faculty of ScienceSouth Valley University

In this paper, the effects of both rotation and m.g.etic field of the peristaltic transport of a second-order fluid throug. a porous m.dium.in a channel are studied analytically and com.uted num.rically. The m.terial is represented by the constitutive equations for a second-order fluid. Closed-form.solutions under the consideration of long.waveleng.h and low Reynolds num.er is presented. The analytical expressions for the pressure g.adient, pressure rise, friction force, stream.function, shear stress, and velocity are obtained in the physical dom.in. The effects of the non-dim.nsional wave am.litude, porosity, m.g.etic field, rotation, and the dim.nsionless tim.-m.an flow in the wave fram. are analyzed theoretically and com.uted num.rically. Num.rical results are g.ven and illustrated g.aphically in each case considered. Com.arison was m.de with the results obtained in the presence and absence of rotation, m.g.etic field, and porosity. The results indicate that the effects of the non-dim.nsional wave am.litude, porosity, m.g.etic field, rotation, and the dim.nsionless tim.-m.an flow are very pronounced in the phenom.na.

关键词： peristaltic flow second-order fluid m.g.etic field porous m.dium