简介:Toexploretheeffectofthegassourceflowrateontheactualdieselexhaustparticulatematter(PM),atestbenchfordieselengineexhaustpurificationwasconstructed,usingindirectnonthermalplasmatechnology.Theeffectsofdifferentgassourceflowratesonthequantityconcentration,composition,andapparentactivationenergyofPMwereinvestigated,usinganengineexhaustparticlesizerandathermo-gravimetricanalyzer.Theresultsshowthatwhenthegassourceflowratewaslarge,notonlythemaximumpeakquantityconcentrationsofparticleshadalargedrop,butalsothepeakquantityconcentrationsshiftedtosmallerparticlesizesfrom100nmto80nm.Whenthegassourceflowratewas10Lmin~(-1),thetotalquantityconcentrationgreatlydecreasedwheretheremovalrateofparticleswas79.2%,andthevariationofthedifferentmodeparticleproportionwasobvious.Non-thermalplasma(NTP)improvedtheoxidationabilityofvolatilematteraswellasthatofsolidcarbon.However,theNTPgassourceratehadlittleeffectsonoxidationactivityofvolatilematter,whileitstronglyinfluencedtheoxidationactivityofsolidcarbon.Consideringthequantityconcentrationandoxidationactivityofparticles,agassourceflowrateof10Lmin~(-1)wasmoreappropriateforthepurificationofparticles.
简介:AdsorptionequilibriumexperimentsofphenolontheNKAIIresinareseparatelyconductedinthepresenceandabsenceofultrasoundatambienttemperature.Theisothermofphenolonthepolymeradsorbentinthepresenceofultrasonicfieldisfirstlyreported.Resultsindicatedthattheisothermofphenoldeterminedinthepresenceofultrasoundislowerthanthatintheabsenceofultrasound.Inaddition,experimentsalsoshowthattheuseofultrasoundtotheadsorptionsystemofthephenolaqueoussolutionandNKAⅡresincouldcausetherisingofthetemperatureofthesystemintheorderof6^-C.TheeffectofultrasoundontheisothermofthephenolontheNKAⅡresinmostlyascribestothethermaleffectandthenon-thermaleffectofultrasonicfield.andtheroleofthelaterisgreaterthanthatoftheformer.
简介:Inthisstudy,aporousinsertedregenerativethermaloxidizer(PRTO)systemwasdevelopedfora125kWindustrialcopper-meltingfurnace,duetoitsadvantagesoflowNOxemissionsandhighradiantefficiency.Zirconiumdioxide(ZrO2)ceramicfoamswereplacedintothecombustionzoneofaregenerativethermaloxidizer(RTO).DifferentperformancecharacteristicsoftheRTOandPRTOsystems,includingpressuredrop,temperaturedistribution,emissions,andenergyefficiency,wereevaluatedtostudytheeffectsoftheporousinsertsonnon-premixedCH4combustion.ItwasfoundthatthePRTOsystemachievedasignificantreductionintheNOxemissionlevelandafuelsavingofapproximately30%comparedtotheRTOsystem.Itismostsuitableforaleancombustionprocessatanequivalenceratio<0.4withNOxandCOemissionlevelswithin0.002%-0.003%and0.001%-0.002%,respectively.
简介:现在的分析在非线性的热放射的影响下面经过常常动人的表面讨论伊灵·鲍威尔nanofluid的边界层流动。热和集体转移机制在身体上合适的对流边界条件下面被检验。可变热电导率和化学反应的效果也被考虑。用Homotopy分析方法(火腿)的所有深奥分布的系列答案被获得。统治嵌入的流动参数的影响通过图形的插图被讨论。在与温度的关系的热放射参数表演增加趋势介绍,这被观察。然而,化学反应参数展出减少的行为对集中分发。
简介:Basedontheporousmediatheoryandbytakingintoaccounttheeffectsoftheporefluidviscidity,energyexchangesduetotheadditionalthermalconductionandconvectionbetweensolidandfluidphases,amathematicalmodelforthedynamic-thermo-hydro-mechanicalcouplingofanon-localthermalequilibriumfluid-saturatedporousmedium,inwhichthetwoconstituentsareassumedtobeincompressibleandimmiscible,isestablishedundertheassumptionofsmalldeformationofthesolidphase,smallvelocityofthefluidphaseandsmalltemperaturechangesofthetwoconstituents.Themathematicalmodelofalocalthermalequilibriumfluid-saturatedporousmediumcanbeobtaineddirectlyfromtheaboveone.SeveralGurtin-typevariationalprinciples,especiallyHu-Washizutypevariationalprinciples,fortheinitialboundaryvalueproblemsofdynamicandquasi-staticresponsesarepresented.Itshouldbepointedoutthatthesevariationalprinciplescanbedegeneratedeasilyintothecaseofisothermalincompressiblefluid-saturatedelasticporousmedia,whichhavebeendiscussedpreviously.
简介:Microcalorimetrywasdevelopedtodeterminethermalconductivities(λ)ofthermalinsulatorswithhollowcylindricalshapes,Aspecialdeviceofspecimentwithresistancethreadswrappedonitssurfaceandelectricheaterplacedinitsholewasdesignedtomeettheneedsofdeterminingλwithoutusingstandardsubstancestocalibratetheinstrument.Aformulaforcalculatingthevalueofλwasderived.Byheatingintheholeandonthesurfaceofthespecimenrespectively,thevaluesofλcanbeobtainedconvenientlybythistechnique.Themethodwastestedwithteflon,plexiglass,quartzglassandp[olyethylene.Theexperimentalvaluesofλforthefoursubstancesagreewellwiththeliteraturesones.Erroranalysiswasalsomadeontheexperimentaldata.Itwasfounrthatthemainfactorsaffectingvaluesofλare:(1)Theerroreofdeterminingthevaluesofheatcumulatedinspecimenandmaterialsinthespacearounditand(2)theerroreofdeterminingthevaluesofinnerandouterradiiofcylindricalspecimen.λ
简介:Theeffectivethermalconductivityofcompositeswithellipsoidalfillersisanalyzedbyusingahomogenizationmethodthatisabletorepresentthemicrostructureprecisely.Inthisstudy,variousparameterssuchasthevolumefraction,shape,anddistributionofthefillerarequantitativelyestimatedtounderstandthemechanismsofheattransferinthecomposite.First,thermalboundaryresistancebetweenresinandfillerisimportantforobtainingcompositeswithhigherthermalconductivity.Second,theanisotropyoftheeffectivethermalconductivityarisesfromcontactbetweenfillerinthecaseofellipsoidalfillerandproduceslowerthermalresistance.Finally,thefillernetworkandthermalresistanceareessentialfortheheattransferincompositesbecausethepathofthermalconductionisimprovedbycontactbetweenneighboringfillerparticles.
简介:Residualstressevolutionregularityinthermalbarrierceramiccoatings(TBCs)underdifferentcyclesofthermalshockloadingof1100℃wasinvestigatedbythemicroscopicdigitalimagecorrelation(DIC)andmicro-Ramanspectroscopy,respectively.Theobtainedresultsshowedthat,asthecyclenumberofthethermalshockloadingincreases,theevolutionoftheresidualstressundergoesthreedistinctstages:asharpincrease,agradualchange,andareduction.TheextensionstressneartheTBCsurfaceisfasttransformedtocompressiveonethroughjustonethermalcycle.Afterdifferentthermalshockcycleswithpeaktemperatureof1100℃,phasetransformationinTBCdoesnothappen,whereasthegeneration,development,evolutionofthethermallygrownoxide(TGO)layerandmicro-cracksarethemainreasonscausingtheevolutionregularityoftheresidualstress.
简介:Acomprehensivetreatmentoffractureoffunctionallygradedmaterials(FGMs)isprovided.Itisassumedthatthematerialpropertiesdependonlyonthecoordinateperpendiculartothecracksurfacesandvarycontinuouslyalongthecrackfaces.Byusingalaminatedcompositeplatemodeltosimulatethema-terialnon-homogeneity,analgorithmforsolvingthesystembasedonLaplacetransformandFouriertransformtechniquesispresented.Unlikeearlierstudiesthatconsideredcertainassumedpropertydistributionsandasinglecrackproblem,thecurrentinvestigationstudiesmultiplecrackproblemintheFGMswitharbitrarilyvaryingmaterialproperties.Transientthermalstressesarepresented.
简介:Thethermalprotectionperformanceofsuperalloyhoneycombstructureinhigh-temperatureenvironmentsareimportantforthermalprotectiondesignofhigh-speedaircrafts.Byusingaself-developedtransientaerodynamicthermalsimulationsystem,thethermalprotectionperformanceofsuperalloyhoneycombpanelwastestedinthispaperatdifferenttransientheatingratesrangingfrom5℃/sto30℃/s,withthemaximuminstantaneoustemperaturereaching950℃.Furthermore,thethermalprotectionperformanceofsuperalloyhoneycombstructureundersimulatedthermalenvironmentswascomputedfordifferenthighheatingratesbyusing3Dfiniteelementmethod,andacomparisonbetweencalculationalandexperimentalresultswascarriedout.Theresultsofthisresearchprovideanimportantreferenceforthedesignofthermalprotectionsystemscomprisingsuperalloyhoneycombpanel.
简介:AbstractFor the detection of steatosis, quantitative ultrasound imaging techniques have achieved great progress in past years. Magnetic resonance imaging proton density fat fraction is currently the most accurate test to detect hepatic steatosis. Some blood biomarkers correlate with non-alcoholic steatohepatitis, but the accuracy is modest. Regarding liver fibrosis, liver stiffness measurement by transient elastography (TE) has high accuracy and is widely used across the world. Magnetic resonance elastography is marginally better than TE but is limited by its cost and availability. Several blood biomarkers of fibrosis have been used in clinical trials and hold promise for selecting patients for treatment and monitoring treatment response. This article reviews new developments in the non-invasive assessment of non-alcoholic fatty liver disease (NAFLD). Accumulating evidence suggests that various non-invasive tests can be used to diagnose NAFLD, assess its severity, and predict the prognosis. Further studies are needed to determine the role of the tests as monitoring tools. We cannot overemphasize the importance of context in selecting appropriate tests.
简介:Thispaperinvestigatesthemathematicfeaturesofnon-linearmodelsanddiscussestheprocessingwayofnon-linearfactorswhichcontributestothenon-linearityofanonlinearmodel.Onthebasisoftheerrordefinition,thispaperputsforwardanewadjustmentcriterion,SGPE.Last,thispaperinvestigatesthesolutionofanon-linearregressionmodelinthenon-linearmodelspaceandmakesthecomparisonbetweentheestimatedvaluesinnon-linearmodelspaceandthoseinlinearmodelspace.
简介:由测试melt索引(MI),张力的力量;碎延期比率,polyoxymethylene(POM)的热变老率被分析;比较。表面形态学;POM表面的功能组的类型被观察;由SEM分析了;XPS。结果证明MI在120°C与变老的时间逐渐地珍视增加,显示热氧化分解occurrs慢慢地。在张力的力量上的20天的热变老的效果;打破POM的延期比率不是明显的,证明变老POM是相当一个长过程。在以后105天,裂开的热变老;POM表面上的搽粉的occurr。XPS决心以前显示出样品的C1s系列;在变老以后,包括C-C的二座山峰;公司,当在变老以后C-C的内容减少时;公司的内容增加,显示POM的热变老主要是碎;C-C债券分解。原来的样品的O1s/C1s比率是56.98%;在105天的热变老以后,比率是72.92%。