简介:ObjectivePorencephaliccystpresentingwithotologicinvolvementisuncommon.Onlyafewcaseshavebeenreported.Wereportararecaseofcerebrospinalfluid(CSF)otorrheacausedbyamassiveporencephaliccystencompassingthelefttemporalandoccipitallobes.TheCSFleakwasrepairedsuccessfullyusingatransmastoidapproachwithfacia,abdomenfatandfibringluetosealtheosseousdefectsinthesinoduralangle.AreviewoftheliteratureconcerningporencephaliccystandCSFotorrheaisalsopresented.
简介:Osteocytesactasmechanosensorsinbone,whichcansendmechanicalsignalsdirectlytoosteoblaststhroughgapjunctions.However,underphysiologicalconditionsthenumberofgapjunctionsislimitedbecauseofthequantityvarianceofthetwokindsofcells.Inthisstudy,thepossibilityofindirectinteractionbetweenthesetwocellswasinvestigated.Anewflowchamperwasdesignedinwhichosteocytesandosteoblastswerecoculturedintwochampersseparately.OsteocyteswereexposedtofluidflowandthentheALPactivity,osteocalcinandosteopotinofosteoblastsweredetermined.TheresultsshowedthateitherALPactivityorproductionofosteocalcinandosteopotininosteoblaststhatwerecoculturedwithshearedosteocytesincreased,whichindicatedthatosteocytescouldregulateosteoblastsindirectlythroughsomesolublefactors.
简介:Vibrationofacircularmembraneincontactwithafluidhasextensiveapplicationsinindustry.Thenaturalvibrationfrequenciesfortheasymmetricfreevibrationofacircularmembraneincontactwithaboundedincompressiblefluidarederivedinthispaper.Consideringsmalloscillationsinducedbythemembranevibrationinanincompressibleandinviscidfluid,thevelocitypotentialfunctionisusedtodescribethefluidfield.Twoapproachesareusedtoderivethefreevibrationfrequenciesofthesystem,whichincludeavariationalformulationandanapproximatesolutionemployingtheRayleighquotientmethod.Agoodcorrelationisfoundbetweenfreevibrationfrequenciesevaluatedbythesemethods.Finally,theeffectsofthefluiddepth,themassdensity,andtheradialtensiononthefreevibrationfrequenciesofthecoupledsystemareinvestigated.
简介:ThispaperestablishesthevelocityfieldandtheadequateshearstresscorrespondingtothemotionofanOldroyd-BfluidbetweentwoinfinitecoaxialcircularcylindersbymeansoffiniteHankeltransforms.Theflowofthefluidisproducedbytheinnercylinderwhichappliesatime-dependentlongitudinalshearstresstothefluid.Theexactanalyticalsolutions,presentedinseriesformintermsofBesselfunctions,satisfyallimposedinitialandboundaryconditions.ThegeneralsolutionscanbeeasilyspecializedtogivesimilarsolutionsforMaxwell,secondgradeandNewtonianfluidsperformingthesamemotion.Finally,somecharacteristicsofthemotionaswellastheinfluenceofthematerialparametersonthebehaviorofthefluidmotionaregraphicallyillustrated.
简介:Toanalyzeanddepictcomplicatedfluidbehaviorsinfracturedporousmediawithvariablypermeablematrix,anintegrateddiscretecomputationalalgorithmisproposedbasedonlatticeBoltzmannmethod(LBM).Thispapercombineswiththeexternalforcemodelandstatisticalmaterialphysicstoeffectivelydescribethefeaturechangeswhilethefluidpassesthroughthefractureswithinthepermeablematrix.Asanapplicationexample,atwodimensionalrocksampleisreconstructedusingthedigitalimageandcharacterizedwithdifferentfeaturevaluesateachLBMgridtodistinguishpores,impermeableandpermeablematrixbystatingitslocalphysicalproperty.ComparedwiththeconventionalLBM,theresultsdemonstratetheadvantagesofproposedalgorithminmodelingfluidflowphenomenoninfracturedporousmediawithvariablypermeablematrix.
简介:Takingextractionrateasanindicator,theextractiontechnologyofChinese-firheartwoodbysupercriticalcarbondioxidetreatmentwasstudied,andtheextractionrateoftheSFE-CO2methodwascomparedtothatoftraditionalextractionmethod.Theresultsshowthatwhenextractionprocessingconditionwere:extractionpressure30MPa,extractiontemperature40℃,extractiontime120m,andflowvelocity20kg/h,theextractionrateofSFE-CO2was0.99%,0.20%morethanthatofthetraditionalextractionmethod.However,takingthecostintoconsideration,itisproposedthatthetraditionalextractionisusedunlesstherearespecificrequirements.
简介:为了提供,身体上在地区性的规模为风侵蚀研究基于风建模,3D计算液体动力学(CFD)风模型被开发。模型基于海军司烧方程用C语言被规划,并且它作为开放源代码自由地可得到。与空间分析和建模工具(SAMT)综合,风模型举办方便输入准备和强大的产量可视化。为了验证风模型,,一系列实验在一条风隧道被进行。一个堵住的流入实验被设计在基本液体进程的模拟上测试模型的性能。一个圆障碍实验被设计检查模型是否能在风地上模仿障碍的影响。结果证明测量并且模仿的风地有高关联,和风模型能两个都模仿风的基本过程和对风地的障碍的影响。这些结果显示出风模型的高可靠性。一个区域的一个数字举起模型(DEM)(长的3800m和1700m宽)在在内部蒙古的Xilingele草地(自治区域,中国)被用于模型,和一块3D风地成功地被产生了。由风隧道实验的模型和足够的确认的清楚的实现在地区性的规模为风侵蚀的预言和评价打了一个稳固的基础。
简介:Ananalyticalmodelisdevelopedtostudythesurfaceeffectsonthevibrationbehaviorincludingthenaturalfrequencyandthecriticalflowvelocityoffluid-conveyingnanotubesembeddedinanelasticmedium.TheeffectsofsurfaceelasticityandresidualsurfacestressareaccountedthroughthesurfaceelasticitymodelandtheYoung-Laplaceequation.AWinkler-typefoundationisemployedtomodeltheinteractionofnanotubesandthesurroundingmedium.Theresultsshowthatthesurfaceeffectshavemoreprominentinfluencesonthenaturefrequencywithsmallernanotubethickness,largeraspectratioandlargerelasticmediumconstants.Bothsurfacelayersandtheelasticmediumenhancethestabilityofnanotubes.Thisstudymightbehelpfulfordesigningthefluid-conveyingnanotubedevicesinNEMSandMEMSsystems.
简介:Atwo-dimensional(2D)numericalmodelisdevelopedforthewavesimulationandpropagationinawaveflume.Thefluidflowisassumedtobeviscousandincompressible,andtheNavier-Stokesandcontinuityequationsareusedasthegoverningequations.Thestandardk-εmodelisusedtomodeltheturbulentflow.TheNavierStokesequationsarediscretizedusingthestaggeredgridfinitedifferencemethodandsolvedbythesimplifiedmarkerandcell(SMAC)method.Wavesaregeneratedandpropagatedusingapistontypewavemaker.Anopenboundaryconditionisusedattheendofthenumericalflume.Somestandardtests,suchasthelid-drivencavity,theconstantunidirectionalvelocityfield,theshearingflow,andthedam-breakonthedrybed,areperformedtovalidthemodel.Todemonstratethecapabilityandaccuracyofthepresentmethod,theresultsofgeneratedwavesarecomparedwithavailablewavetheories.Finally,theclusteringtechnique(CT)isusedforthemeshgeneration,andthebestconditionissuggested.
简介:Intheunderwater-shockenvironment,cavitationoccursnearthestructuralsurface.Thedynamicresponseoffluid-structureinteractionsisinfluencedseriouslybythecavitationeffects.Itisalsothedifficultyinthefieldofunderwaterexplosion.Withthetraditionalboundaryelementmethodandthefiniteelementmethod(FEM),itisdifficulttosolvethenonlinearproblemwithcavitationeffectssubjectedtotheunderwaterexplosion.Tosolvethisproblem,undertheconsiderationofthecavitationeffectsandfluidcompressibility,withfluidvisciditybeingneglected,a3Dnumericalmodeloftransientnonlinearfluid-structureinteractionsubjectedtotheunderwaterexplosionisbuilt.Thefluidspectralelementmethod(SEM)andtheFEMareadoptedtosolvethismodel.AftercomparisonwiththeFEM,itisshownthattheSEMismoreprecisethantheFEM,andtheSEMresultsareingoodcoincidencewithbenchmarkresultsandexperimentresults.Basedonthis,combinedwithABAQUS,thetransientfluid-structureinteractionmechanismofthe3Dsubmergedsphericalshellandshipstiffenedplatessubjectedtotheunderwaterexplosionisdiscussed,andthecavitationregionanditsinfluenceonthestructuraldynamicresponsesarepresented.Thepaperaimsatprovidingreferencesforrelevantresearchontransientfluid-structureinteractionofshipstructuressubjectedtotheunderwaterexplosion.
简介:Thebasic-nitrogenaromaticcompoundsinfeedstocksandliquidproductsfromthemicro-reactorandsolublecomponentsofcokeobtainedduringfluidcatalyticcracking(FCC)processwereanalyzedbythemicro-electrosprayionization(ESI)9.4TFouriertransformioncyclotronresonancemassspectrometry(FT-ICRMS)withanaveragemassresolvingpowerof300000atamassrangeof100-1200.Theanalyticalresultsrevealedthatthecokergasoil(CGO)containedahigherabundanceofbasic-nitrogenaromaticcompoundswiththetypeof-5Nto-9Ncomparedwiththoseindeasphaltedoil(DAO)andmixedFCCfeedstock.Aftercatalyticcracking,theabundanceoflowlycondensedbasic-nitrogenaromaticcompoundswasmuchlessthanthoseofhighlycondensedaromaticsintheliquidproducts,withthecarbonnumbermainlyrangingfrom6to25andtheaveragecarbonnumberoftheside-chainsequatingto1-5.Onthecontrary,withrespecttothesolublecomponentsofcoke,theabundanceoflowlycondensedbasic-nitrogenaromaticcompoundswasmorethanthoseofhighlycondensedaromatics,andthecarbonnumberrangedfrom12to30,whichwasmuchsmallerthanthatofthemixedFCCfeedstockbutslightlylargerthanthatofthecrackedliquidproducts.TheseresultshaveprovidedsomefundamentalinformationonFCCprocess.