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Release m.dels for leaks from.high-pressure hydrogen storage system.

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Chinese Science Bulletin 2014年第19期59卷 2302-2308页

作者： Xue-Fang Li david m. christopher Jing-Liang Bi Key Laboratory for Therm.l Science and Power Engineering of m.nistry of Education Tsinghua University

Sim.lations and analyses of experim.ntal data from.leaks from.high-pressure hydrogen storage system. will require knowledge of the stagnation state tim. histories and stream.properties exiting the *** analytical ideal-gas m.del based on the ideal gas state equation and a com.uter program.m.king use of the NIST standard reference database(REFPROP)were developed to m.del the entire process of leaks from.high-pressurized hydrogen gas *** results obtained by the two m.thods agree with each other *** the gas behavior departs from.the ideal gas properties at high pressures,the actual stagnation pressure and tem.erature decay m.re rapidly than with the ideal-gas assum.tion.

关键词：存储系统高压氢理想气体状态方程泄漏释放模式理想气体模型计算机程序时间历程

Heat Transfer in the m.crolayer Under a Bubble During Nucleate Boiling

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Tsinghua Science and Technology 2010年第4期15卷 404-413页

作者： david m.christopher 张璐 Key Laboratory for Therm.l Science and Power Engineering of m.nistry of Education Department of Thermal Engineering Tsinghua University

m.ny studies have shown that a very thin liquid m.crolayer form. under vapor bubbles during nucleate boiling. The heat transfer from.the surface to the bubble is then significantly affected by this m.- crolayer and the curved region leading into the m.crolayer. Various m.dels have been developed to predict the m.crolayer shape and the heat transfer along the curved interfacial region, but they tend to have incon- sistent boundary conditions or unrealistic results. This paper presents a theoretical m.del to predict the m.- crolayer thickness and the heat transfer rates for a variety of conditions. The results show how the wall su- perheat, the Ham.ker constant, the bubble radius, and the accom.odation coefficient at the interface affect the evaporation heat transfer rates and the m.crolayer shape for a large range of conditions for water and FC 72. The m.crolayer results are then shown to com.are well with predictions m.de by solving the Na- vier-Stokes equations in the m.crolayer.

关键词： nucleate boiling bubble growth heat transfer m.crolayer

Jet flows from.bubbles during subcooled pool boiling on m.cro wires

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Science China(Technological Sciences) 2005年第4期48卷 385-402页

作者： D. m. christopher Laboratory of Phase Change and Interfacial Transport Phenom.na Department of Thermal Engineering Tsinghua University Beijing 100084 China

An experim.ntal investigation was conducted on subcooled nucleate boiling on ultra-sm.ll wires having diam.ters of 25―100 μm. High-speed photography and laser PIV (Particle Im.ge Velocim.try) technology were used to visually observe the bubble dynam.cs. For highly subcooled boiling at m.derate heat fluxes, the bubbles generally rem.ined attached to the m.cro heating wires and bubble-top jet flows were clearly observed. Sm.ller bubbles usually had stronger bubble-top jet flows, while larger bubbles seem.d to produce m.lti-jet flows. The structures of the bubble-top jet flows, as well as m.lti-jet flows, were proposed from.the experim.ntal observation. A m.del was developed to describe jet flow phenom.na from.bubbles on m.cro wires. Num.rical sim.lations for bubbles having diam.ter of 0.03 and 0.06 m. showed that both the bubble-top and m.lti-jet flows were induced by a strong m.rangoni effect due to high tem.erature gradients near the wire. The predicted velocity m.gnitudes and flow structures agreed very well with experim.ntal m.asurem.nts. The bubble size relative to the wire is an im.ortant factor affecting the jet flow structure. For a 0.03 m. bubble on a 0.1 m. wire, only a bubble-top jet flow form., while a com.lex m.lti-jet flow pattern form. around the bubble with a weak bubble-top jet and two side jet flows for a 0.06 m. bubble.

关键词： subcooled boiling, bubble, m.lti-jet, jet flow, PIV, m.rangoni, CFD.

Num.rical analysis for the prediction of bum. prone conditions:A southern Appalachian pillar coal bum. case study

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International Journal of m.ning Science and Technology 2021年第1期31卷 75-81页

作者： christopher Newm.n david Newm.n Appalachian m.ning&Engineering Inc.LexingtonKY 40503USA

Two m.ners were fatally injured when a pillar bum. occurred during retreat m.ning in a southern West Virginia coal *** m.ne was operating in the Eagle seam.with overm.ning in the No.2 Gas and Powellton seam..A coal bum. is defined as a sudden and violent failure of coal caused by the release of stored strain energy in the *** significant strides have been m.de by academ.a,industry,and regulatory agencies to better understand bum. conditions and m.tigation techniques,coal bum.s represent a long standing,highly site-specific engineering problem.in which the exact failure m.chanism.is not clearly *** this case history,a cut-by-cut analysis of retreat m.ning operations was conducted on the 4 East m.in leading up to the pillar bum. *** input param.ters were derived from.site-specific geologic inform.tion and m.ne geom.try for the analysis of pillar stress conditions and energy release using *** overview of stress conditions in the panel was presented including a precursor event that occurred two crosscuts inby the bum. *** m.thodology presented in the paper for the evaluation of the fatal bum. event can be used for the identification of bum. prone conditions prior to developm.nt and retreat of a m.ning area.

关键词： Bum. Burst Coal Energy release rate Lam.del Num.rical m.deling

CO2 degassing and m.lting of m.tasom.tized m.ntle lithosphere during rifting-Num.rical study

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Geoscience Frontiers 2019年第4期10卷 1409-1420页

作者： Weronika Gorczyk christopher m. Gonzalez University of Western Australia Centre for Exploration TargetingSchool of Earth SciencesARC Centre of Excellence for Core to Crust Fluid SystemsPerthWestern AustraliaAustralia School of Earth Atmosphere and EnvironmentMonash University ClaytonMelbourneVICAustralia

:Reactivation of m.tasom.tized m.ntle lithosphere m.y occur during continental extension,which is an im.ortant com.onent of plate *** lower m.st part of the m.tasom.tized dom.ins in the subcontinental m.ntle lithosphere can be locally enriched in ***,partial m.lting of these m.tasom.tized dom.ins m.y play a crucial role in the global carbon ***,little is known about this process and up until now few num.rical constraints are *** we address this knowledge gap and use a 2-D high resolution petrological-therm.m.chanical m.del to assess lithospheric ***2 degassing and *** test 4 lithospheric thicknesses:90,110,130 and 200 km.with a 10 km.thick m.tasom.tized layer at the base using CO2 of 2 wt.%in the bulk *** carbonate enriched layer is stable below^3 GPa(>110 km.for a tem.erature of 1300℃;therefore,we only observe degassing patterns for lithospheric m.dels that are 130 km.and 200 km.*** m.tasom.tized layer for the 130 km.thick lithosphere m.stly com.rises carbonatite m.lting,whereas in the 200 km.thick scenario propagation of m.lt developm.nt from.kim.erlites to carbonatites occurs as the m.tasom.tic m.ntle is exhum.d during *** num.rical m.dels fit well into natural rifting zones of the European Cenozoic Rift System.for young(shallow)and of the North Atlantic Rift for old(thick)lithosphere.

关键词： Rifting m.ntle CO2 degassing Carbonate m.lting

Bubble Coalescence Heat Transfer During Subcooled Nucleate Pool Boiling

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工程热物理学报 2012年第12期33卷 2171-2175页

作者： Abdoulaye Coulibaly LIN Xipeng Bi Jingliang david m.christopher Departm.nt of Therm.l Engineering Tsinghua University

Bubble coalescence during subcooled nucleate pool boiling was investigated experim.ntally using constant wall tem.erature boundary conditions while the wall heat flux was m.asured at a various locations to understand the effects of coalescence on the heat *** observations showed that the coalesced bubble m.ved and oscillated on the heater surface with significant heat transfer variations prior to *** observations also showed coalescence with no increase in the heat transfer *** heat flux for boiling with coalescence fluctuated m.ch m.re than for single bubble boiling due to the vaporization of the liquid layer trapped between the bubbles.

关键词： m.croheater pool boiling bubble coalescence bubble dynam.cs

Assessing risks from.m.ning-induced ground m.vem.nts near gas wells

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International Journal of m.ning Science and Technology 2020年第1期30卷 11-16页

作者： christopher m.rk Gregory m.Rum.augh m.ne Safety and Health Adm.nistration PittsburghPAUSA

The proliferation of unconventional gas well developm.nt in the Northern Appalachian coalfields has raised a num.er of m.ne safety *** wells,which extract gas from.deep shale form.tions,are characterized by gas volum.s and pressures that are significantly higher than those observed at m.ny conventional *** gas is com.osed largely of m.thane as well as other *** of planned and actively producing wells penetrate protective coal pillars or barriers within active m.ne boundaries,including chain pillars located between longwall *** released from.a well dam.ged by m.ning-induced ground m.vem.nts could pose a risk to m.ners by flowing into the m.ne *** m.ning-induced ground m.vem.nts that m.y cause well dam.ge include conventional subsidence,non-conventional subsidence(*** plane slip),pillar failure,and floor *** paper describes the known risk factors for each of the four failure *** includes a fram.work that can guide the risk assessm.nt process when m.ning takes place near gas or oil wells.

关键词： Gas well Subsidence Coal protection pillar Risk m.trix Longwall m.ning

Influence of size effect and boundary conditions on tem.erature overshooting in nanoscale therm.l conduction

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Chinese Science Bulletin 2014年第12期59卷 1334-1339页

作者： Xuefang Li m.ngtian Xu david m.christopher Key Laboratory for Therm.l Science and Power Engineering of m.nistry of Education Tsinghua University Institute of Therm.l Science and Technology Shandong University

The tem.erature overshooting phenom.non in one-dim.nsional nanoscale heat conduction in thin film. is studied for various boundary *** results show that when ballistic heat transport strongly affects the heat transport process,tem.erature overshooting is m.re likely to occur.A sudden increase of tem.erature on only one surface of a thin film.cannot trigger tem.erature overshooting,while sym.etric boundary tem.erature perturbations lead to the largest tem.erature *** heat conduction is also studied in a nanoscale *** analytic results show that Fourier’s law m.y severely underestim.te the tem.eratures in nanofilm. as well as in nanoareas when tem.erature overshooting occurs.

关键词：边界温度过冲现象边界条件纳米级热传导尺寸效应纳米薄膜热传递过程

m.tilin and ghrelin gene experienced episodic evolution during prim.tive placental m.m.al evolution

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Science China(Life Sciences) 2010年第6期53卷 677-682页

作者： IRWIN m. david Departm.nts of Laboratory m.dicine and Pathobiology and the Banting and Best Diabetes Centre University of Toronto

m.tilin and ghrelin,m.m.ers of a structure-function-related horm.ne fam.ly,play im.ortant roles in gastrointestinal function,regulation of energy hom.ostasis and growth horm.ne *** observed episodic evolution in both of their prehorm.ne gene sequences during prim.tive placental m.m.al evolution,during which m.st of the nonsynonym.us changes result in radical *** note,a functional obestatin horm.ne m.ght have only originated after this episodic evolution *** in placental m.m.al evolution,a series of biology com.lexities *** the sam. tim. the m.tilin and ghrelin prehorm.ne genes,which play im.ortant roles in several of these processes,experienced episodic evolution with dram.tic changes in their coding *** observations suggest that som. of the lineage-specific physiological adaptations are due to episodic evolution of the m.tilin and ghrelin genes.

关键词： m.tilin ghrelin episodic evolution