简介：Anacousticbasedinstrument,theABSAcousticBubbleSpectrometer??(ABS),wasinvestigatedforthedetectionandquantificationofbubblesinbiologicalmedia.Theseincludeviscoelasticmedia(blood),materialsofvaryingdensity(boneintissue),non-homogenousdistributionofbubbles(intravenousbubblyflow),andbubblesmigratingintissue(decompressionsickness,DCS).TheperformanceoftheABSwasdemonstratedinaseriesoflaboratoryexperiments.Validationofthecodewasperformedusingaviscoelasticpolymersolution,Polyox,inwhichthebubblesizedistributionandvoidfractionweredeterminedbyABSmeasurementsandwithimageanalysisofhighspeedvideos.ThesetestsshowedthattheaccuracyoftheABSwasnotsignificantlyaffectedbyviscoelasticityforbubblessmallerthan200microns.TheABSdetectionandmeasurementofnon-homogenousbubbledistributionswasdemonstratedusingabubblyflowthroughasimulatedveinsurroundedbytissue.Thescatterofacousticsignalsduetobonesintheacousticpathwaywasalsoinvestigated.Thesein-vitroexperimentsweredoneusingmeat(beef)asatissuesimulant.Decompressionexperimentsweredoneusingbeefmeatwhichwasheldunderwaterathighpressure(9.9atm)thenrapidlydecompressed.Bubblesizedistributionsandvoidfractioncalculationsintheseexperimentswerethenvalidatedusingimageanalysisofhighspeedvideo.Inaddition,preliminaryexperimentswereperformedwiththeUSNavyMedicalResearchCenter,demonstratingtheutilityofthemodifiedABSsystemindetectingtheevolutionofbubblesinswineundergoingdecompressionsickness(DCS).TheseresultsindicatethattheABSmaybeusedtodetectandquantifytheevolutionofbubblesin-vivoandaidinthemonitoringofDCS.

简介：Aerationisanimportantfactoraffectingthebiologicalaerationfilter.Withasetofexperimentdevicespeciallydesignedforthepurpose,andtheparticleimagevelocimetrytechnique,thevelocityfieldofthegas-liquidtwo-phaseflowisstudiedunderdifferentconditions.Thevarioussimulatedaerationstateswereactuallyappliedtotheexperimentaldeviceofsewagetreatment,andtheresultsofthenumericalsimulationwereverified.Thefinalexperimentalresultsindicatethatthemostefficientstateoccurswhentheratioofwaterinaerationtankh/w=1,thediameterofcapillarytubesd=0.6mmandthevelocityofbubblesv=0.3m/s.