简介:TheobjectiveofthisresearchwastoexamineifcertainstrainsofBacillusbacteria,couldsurviveindrypowderproductsandifso,couldthebacteriadegradeorganiccontaminantsinsalinewastewateronaship.Aspartofthestudy,weisolated7domesticatedstrainsnamedNY1,NY2,…,andNY7,thestrainNY6showedtohavethebestperformancefororganicmatterdegradationandcouldsurviveindrypowdermorethan3months.NY6wasidentifiedasBacillusaerius,basedonthemorphologicalandphysic-chemicalproperties.Itsoptimalgrowthconditionswereasfollows:salinitywas2%;temperaturewas37℃;pHwasin6.5-7.0;bestratioofC:N:Pwas100:5:1.ThecapabilityofitsdrypowderforChemicalOxygenDemand(COD)removalwas800mgCOD/ginsynthesizedmarinewastewaterwith2%salinity.Thesporesinthedrypowderwere1.972×108g-1.
简介:Ananalyticalstudywaspresentedonactivecontrolofsoundtransmissionintoavibro-acousticenclosurecomprisingtwoflexibleplates.Twotypesofactuatorswereused,i.e.acousticactuatoranddistributedleadzirconatetitanatepiezoelectric(PZT)actuatorinsteadofpointforceactuator.Usingthemodalacoustictransferimpedance-mobilitymatrices,theexcitationandinteractioninthecoupledsoundtransmissionsystemcanbedescribedwithclearphysicalsignificance.Withthecontrolsystemdesignedtogloballyreducethesoundfield,differentcontrolsystemconfigurationswereconsidered,includingthestructuralactuatorontheincidentplate,actuatoronthereceivingplate,acousticactuatoronthecavity,andtheircombinations.Theeffectivenessandperformanceofthecontrolstrategycorrespondingtoeachsystemconfigurationwerecomparedanddiscussed.Theroleandcontrolmechanismofeachtypeofactuatorwereofparticularinterest.Itwasshownthattheincidentplateactuatoriseffectiveincontrollingthecavity-dominatedmodesandthestructuralmodesdominatedbytheincidentplateandreceivingplate.Twomaincontrolmechanismsareinvolvedinthiscontrolconfiguration,i.e.,modalsuppressingandmodalrearrangement.Forcontrolsystemconfigurationwithonlyacousticactuatorintheenclosure,themechanisminvolvedinthisarrangementispurelymodalsuppression.Desirableplacementsofstructuralactuatorsintermsoftotalpotentialenergyreductionwerealsodiscussed.