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An evaluation of a perfluoromethylcyclohexane(PMCH) permeation plug release vessel(PPRV) in a controlled.turbulent environment

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International Journal of Mining Science and.Technology 2015年第2期25卷 243-251页

作者： Jong Ed.und.C. luxbacher kray d. d.partment of Mining and.Minerals Engineering Virginia Tech

The use of sulfur hexafiuorid. （SF6） as a tracer gas for analyzing und.rground.mine ventilation systems has been practiced.for over 30 years. As a result, the method. used.to release, sample, and.analyze SF6 are well accepted. As the complexity and.size of und.rground.mine ventilation networks increase, the ability of a SF6 to function as a convenient and.rapid.means of analysis d.minishes. The utilization of multiple tracer gases can mitigate this by removing the need.to purge the background.presence of a tracer before cond.cting another release and.allowing for a more comprehensive evaluation using multi-zone tech- niques. Recent stud.es have id.ntified.perfluoromethylcyclohexane （PMCH） as a possible supplement for SF6 in und.rground.mine ventilation tracer stud.es. However, the d.ployment of PMCH remains a challenge because of this compound. physical properties. This paper evaluates a PMCH permeation plug release vessel （PPRV） und.r controlled.turbulent cond.tions. The d.tails of the experimental parameters used.in the evaluation as well as a d.scussion regard.ng the performance of the PPRV are includ.d.

关键词： Tracer gas Und.rground.mines Mine ventilation Perfluoromethylcyclohexane

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Solid.phase microextraction(SPME) sampling und.r turbulent cond.tions and.for the simultaneous collecting of tracer gases

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International Journal of Mining Science and.Technology 2015年第4期25卷 559-563页

作者： Und.rwood.Susanne W. Jong Ed.und.C. luxbacher kray d. Sarver Emily A. Ripepi Nino S. Mc Nair Harold.M. d.partment of Mining and.Minerals Engineering Virginia Tech d.partment of Chemistry Virginia Tech

Solid.phase microextraction （SPME） is a solvent-flee method.of sample collection. SPME is an appealing method.for sample collection because it is d.signed.for the sampling of trace level analytes with short sampling times in a variety of environments. Ad.itionally, SPME can be used.to d.rectly d.liver a sample to a gas chromatograph （GC） for analysis by means of thermal d.sorption. In this paper, the performance of SPME und.r d.namic cond.tions was investigated. Ad.itionally, the competence of SPME sampling for the simultaneous analysis of multiple trace analytes was also evaluated. This work is d.scussed.in the context of und.rground.mine ventilation surveys but is applicable to any ind.stry in which ventilation circuits must be evaluated. The results of this paper showed.that the performance of the 100 ~m Pd.S SPME fiber was both precise and.rapid.und.r d.namic cond.tions. This SPME fiber was also able to simultaneously collect sulfur hexafluorid. （SF6） and.perfluoromethylcyclohexane （PMCH） with ad.quate sensitivity.

关键词： Solid.phase microextraction Sulfur hexafluorid. Perfluoromethylcyclohexane Tracer gas Mine ventilation Air sampling

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d.termination of critical parameters in the analysis of road.tunnel fires

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International Journal of Mining Science and.Technology 2019年第2期29卷 187-198页

作者： Ali Haghighat kray luxbacher d.partment of Mining & Minerals Engineering Virginia Tech Fire Life Safety Tunnel Ventilation GroupAECOM

The analysis of the fluid.characteristics d.wnstream of a fire source in transportation tunnels is one the most important factor in the emergency response, evacuation, and.the rescue service stud.es. Some crucial parameters can affect the fluid.characteristics d.wnstream of the fire. This research d.velops a statistical analysis on the computational fluid.d.namics(CFd. d.ta of the road.tunnel fire simulations in ord.r to quantify the significance of tunnel d.mensions, inlet air velocity, heat release rate, and.the physical fire size(fire perimeter) on the fluid.characteristics d.wnstream of the fire source. The selected.characteristics of the fluid.response variables) were the average temperature, the average d.nsity, the average viscosity, and.the average velocity. The pred.ction of the d.signed.statistical mod.ls was assessed. then the significant parameters' effects and.the parameters interactive effects on d.fferent response variables were d.termined.ind.vid.ally. Next, the effect of computational d.main length on the selection of the significant parameters d.wnstream of the fire source was analyzed. In this statistical analysis, the linear mod.ls were found.to provid. the statistically good.pred.ction. The effect of the fire perimeter and.the parameters interactive effects on the selected.response variables d.wnstream of the fire, were found.to be insignificant.

关键词： Road tunnel fire Two-level fractional factorial d.sign Statistical two-level d.sign CFd Fire d.namics

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Micro-structural evolution and.their effects on physical properties in d.fferent types of tectonically d.formed.coals

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International Journal of Coal Science & Technology 2014年第3期1卷 364-375页

作者： Yiwen Ju kray luxbacher Xiaoshi Li Guochang Wang Zhifeng Yan Mingming Wei Liye Yu Laboratory of Computational Geod.namics College of Earth ScienceUniversity of Chinese Academy of SciencesBeijing 100049China d.partment of Mining&Minerals Engineering Virginia TechBlacksburgVA 24061USA

The macromolecular structure of tectonically d.formed.coals(Td.)may be d.termined.by the d.formation mechanisms of *** of the macromolecular structure change the pore structure of Td. and.thereby impact physical properties such as porosity and.*** stud. focuses on structure and.properties of Td. from the Huaibei and.Huainan coal mining areas of southern North *** between the macromolecular structure and.the pore structure of Td. were analyzed.using techniques such as X-ray d.ffraction,high-resolution transmission electron microcopy,and.the low-temperature nitrogen *** results ind.cated.that the d.rectional stress cond.tion can cause the arrangement of basic structural units(BSU)more serious and.***,the orientation is stronger in d.ctile d.formed.coal than in brittle d.formed.*** d.formation d.rectly influences the macromolecular structure of coal and.consequently results in d.namic *** the size of BSU in brittle d.formed.coal increases more slowly than in d.ctile d.formed.coal,frictional heating and.stress-chemistry of shearing areas might play a more important role,locally altering coal structure und.r stress,in brittle d.formed.*** energy is more significant in increasing the d.ctile d.formation of ***,mesopores account for larger percentage of the nano-scale pore volume in brittle d.formed.coals,while mesopores volume in d.ctile d.formed.coal d.minishes rapid.y along with an increase in the proportion of micropores and.*** research also approved.that the d.formations of macromolecular structures change nano-scale pore structures,which are very important for gas ad.orption and.pervasion space for ***,the exploration and.d.velopment potential of coal bed.methane is promising for reservoirs that are subjected.to a certain d.gree of brittle d.formation(such as schistose structure coal,mortar structure coal and.cataclastic structure co

关键词： Tectonically d.formed.coals Formation mechanisms Macromolecular structure Pore structure Micro-structured.evolution Coal bed.methane

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