简介:Sandjetinnon-Newtonianviscoplasticfluidisassociatedwithanumberofindustrialandengineeringapplications,includingsandcappingforthereclamationofoilsandstailingspondsandsedimentdepositionintosoftmud.Inthisstudy,severalexperimentswerecarriedoutbydepositingcircularsandjetsverticallyintoviscoplasticfluids,knownasLaponitegel.Thedeformationregimesofsandjetsinthegelwereinvestigated.Theyield-gravityparameterofthedeformedsanddropinthegelwascomputed.
简介:Theprobabilitydistributionsofsandparticles'lift-offandincidentvelocitiesinawind-blownsandfluxplayveryimportantrolesinthesimulationofthewind-blownsandmovement.Inthispaper,theverticalandthehorizontalspeedsofsandparticleslocatedat1.0mmaboveasand-bedinawind-blownsandfluxareobservedwiththeaidofPhaseDopplerAnemometry(PDA)inawindtunnel.Basedontheexperimentaldata,theprobabilitydistributionsofnotonlytheverticallift-offspeedbutalsothelift-offvelocityaswellasitshorizontalcomponentandtheincidentvelocityaswellasitsverticalandhorizontalcomponentscanbeobtainedbytheequaldistancehistogrammethod.Itisfound,accordingtotheresultsoftheχ2-testfortheseprobabilitydistributions,thattheprobabilitydensityfunctions(pdf's)ofthesandparticles'lift-offandincidentvelocitiesaswellastheirverticalcomponentsaredescribedbytheGammadensityfunctionwithdifferentpeakvaluesandshapesandthedownwindincidentandlift-offhorizontalspeeds,respectively,canbedescribedbythelognormalandtheGammadensityfunctions.Thesepdf'sdependonnotonlythesandparticlediameterbutalsothewindspeed.
简介:Inordertoinvestigatetheinfluenceoftheverticalvibrationloadingontheliquefactionofsaturatedsand,onedimensionalmodelforthesaturatedsandwithaverticalvibrationispresentedbasedonthetwophasecontinuousmediatheory.Thedevelopmentoftheliquefactionandtheliquefactionregionareanalyzed.Itisshownthattheverticalvibrationloadingcouldinduceliquefaction.Therateoftheliquefactionincreaseswiththeincreaseoftheinitiallimitstrainorinitialporosityoramplitudeandfrequencyofloading,andincreaseswiththedecreaseofthepermeabilityorinitialmodulus.Itisshownalsothatthereisaphaselaginthesandcolumn.Whenthesandpermeabilitydistributionisnon-uniform,theporepressureandthestrainwillrisesharplywherethepermeabilityisthesmallest,andfracturemightbeinduced.Withthedevelopmentofliquefaction,thestrengthofthesoilfoundationbecomessmallerandsmaller.Inthelimitingcase,landslidesordebrisflowscouldoccur.
简介:WesummarizeinthisoverviewachievementsincurrentresearchfrontiersinAsiansanddustwithemphasisonthemethodforsanddustresearch,thesourcesofsanddustaerosols,emissionofsanddust,mechanismofsanddustweather,chemicaltransformationduringtransport,andinfluencesonclimaticenvironmentandoceans.OurmainresultsshowthatmostofAsiansanddustcomesfromMongolia,theGobiDesert,aridandsemiariddesertareasinnorthwestChina,whichisdividedintoinitialsourcesandenhancedsources.HalfoftheglobalproductionofdustoriginatesfromAsiandustsourceregions.Asiandustweatherissoimmensethatitcancovera5-7-dayjourneyfromthesourcestotheKoreanPeninsula,JapanIslands,andthePacificOceantoevenimpactNorthAmerica.Asiandustweatherplaysanactiveroleinthebiogeochemicalcyclesoftraceelementsinthemid-latitudeNorthernHemisphere.
简介:Immersionofautomotivepartsinafluidizedbedoffoundrysandisusedtobothstripthecastingsfreefrommouldingsandandtoheat-treatthecastingsat500?C.Thefluidbedisheatedbyhotgasesfromaburnerdirectedfirstintoaserpentineheatexchangerlocatednearoneside-walloftherectangulartank,andthenintoadistributorconsistingofhorizontalspargerpipeshavingmaintenancestandpipesfixedintotheiruppersurfaces.
简介:Windblownsandfluxanddunefieldevolvingtowardtheoasishavebeenacommonecologicalandenvironmentalthreatconfrontedbymanycountries.Meanwhile,itisalsoakindofcomplexdynamicalprocessinvolvingmultipletemporalandspatialscaleswhichisstilloutofaccuratedescriptionthroughcurrentfieldobservations.Availablemodelsandreliablequantitativesimulationsareofsignificantvaluetopredictthespreadingrateofdesertificationandprovideanoptimaldesignforsandprevention.Thisp...
简介:Thecomplexityoftheloadsactingontheoffshorewindturbines(OWTs)structuresandthesignificanceofinvestigationonstructuredynamicsareexplained.Testresultsobtainedfromascaledwindturbinemodelarealsosummarized.Themodelissupportedonmonopile,subjectedtodifferenttypesofdynamicloadingusinganinnovativeoutofbalancemasssystemtoapplycyclic/dynamicloads.Thetestresultsshowthenaturalfrequencyofthewindturbinestructureincreaseswiththenumberofcycles,butwithareducedrateofincreasewiththeaccumulationofsoilstrainlevel.Thechangeisfoundtobedependentontheshearstrainlevelinthesoilnexttothepilewhichmatcheswiththeexpectationsfromtheelementtestsofthesoil.Thetestresultswereplottedinanon-dimensionalmannerinordertobescaledtopredicttheprototypeconsequencesusingelementtestsofasoilusingresonantcolumnapparatus.