TUESDAY MORNING, 5 DECEMBER 2017 STUDIO 9, 8:00 AM TO 11:40 AM Session 2aAA ...

63 Pages·2017·0.48 MB·English

TUESDAYMORNING,5DECEMBER2017 STUDIO9,8:00A.M.TO11:40A.M.
Session2aAA
ArchitecturalAcousticsandMusicalAcoustics:PerformanceSpacesforModernMusic
K.AnthonyHoover,Cochair
McKayConantHoover,5655LinderoCanyonRoad,Suite325,WestlakeVillage,CA91362
BruceOlson,Cochair
OlsonSoundDesignLLC,8717HumboltAve.N.,BrooklynPark,MN55444
Chair’sIntroduction—8:00
InvitedPapers
8:05
2aAA1. Historical evolution of sound diffusion in spaces for modern music. Peter D’Antonio, Jeffrey Madison (RPG Acoust.
Systems LLC, 99 South St., Passaic, NJ 07055, [email protected]), and Trevor J. Cox (Acoust. Eng., Univ. of Salford,
Salford,UnitedKingdom)
Thispresentationwillreviewthehistoricalevolutionoftheuseofsounddiffusors,fromtheirinitialuseinrecordingcontrolrooms
toincludealmostallspacesfortheperformance,recording,andauditionofmusic.Shortlyaftertheinventionofthereflectionphase
grating diffusor by Manfred Schroeder in 1973, the quadratic residue diffusor was installed in Michael Fowler Hall, New Zealand,
UndergroundSoundrecordingstudiosinLargo,MD,andintheOakRidgeBoy’sAcornStudioinHenderson,TN.Theinitialaccep-
tanceofthesenewsurfacesledtoinstallationinhundredsofrecordingcontrolroomsandliverooms,hometheaters,stages,auditoria,
and worship spaces. The design of sound diffusors was expanded to use optimization algorithms created by Cox and D’Antonio to
includedecorativeshapestocomplementtheoriginalphasegratingsurfaces,thusopeningtheiruseinallarchitecturalacousticspaces.
Followingabriefreviewofthedesigntheoryoptions,manyapplicationsoverthreedecades,inawiderangeofvenueswillbepresented.
A speculation on what the future holds, based on evolving diffusive designs and advanced manufacturing methods, will also be
presented.
8:25
2aAA2.Tamingreverberationinanoutdooramphitheatre—TheFord.K.AnthonyHoover(McKayConantHoover,5655Lindero
CanyonRd.,Ste.325,WestlakeVillage,CA91362,[email protected])
ThehistoricFordAmphitheatreinHollywood,CA,recentlycompletedanoverallrenovationandexpansion.Thecenterpieceisthe
1,200-seatoutdooramphitheater,whichfeaturesadramaticarroyobackdrop.Thesidewalls,rearwall,towers,andhouseflooringwere
builtofconcretein1931afterabrushfiredestroyedtheoriginal1920woodstructure.Severalsound-absorptivetreatmentshadbeen
appliedtothewallsovertheyearsprevioustoourinvolvement,butexcessivereverberationandsomeanomalousreflectionsremained.
Thenewdesignfeaturesanexpanded“soundwall”thathelpstomitigatehighwaynoisewhileprovidingoptimallightingandcontrol
positions,andofferinganopportunitytoimprovetheacousticaltreatmentscheme.Theresultisauniqueinstallationofdecorativeperfo-
rated-metalpanelsthattamethereverberation,especiallyinthelowfrequencies.Assorteddesignchallenges,apparentarroyohillside
contributions,andtheresultantreverberationwillbediscussed.
8:45
2aAA3.ActiveAcousticsattheAppelRoom,JazzatLincolnCenter.TomWetmore(ColumbiaUniv.,NewYorkCity,NY)and
SteveEllison(MeyerSoundLabs,Inc.,2832SanPabloAve.,Berkeley,CA94702,[email protected])
TheAppelRoom(formerlyAllenRoom)isa483-seatvenueusedprimarilyforjazzperformancesintheJazzatLincolnCenter
complexinNewYorkCity.In2013theConstellationactiveacousticsystembyMeyerSoundwasincorporatedintotheroom’sarchitec-
ture.Thesystemallowsawiderangeofacousticconditionstobesetforanyperformance.Inthefirstfouryearsofoperation,avariety
ofsoloandensemblejazzartistshaveperformedinthisvenue.Thispaperwilldescribetheroom,thesystem,andtheresultsoverthe
firstfouryearsofoperationwithavarietyofmusicians.
2530 J.Acoust.Soc.Am.,Vol.142,No.4,Pt.2,October2017 174thMeeting:AcousticalSocietyofAmerica 2530
9:05
2aAA4.Amplifiedrehearsalandperformancespacesonacommunitycollegecampus.SamOrtallono(VisualPerformingArts,Lee
College,711W.TexasAve.,Baytown,TX77522,[email protected])
Amplifiedrehearsalandperformancespacesonacommunitycollegecampus.LeecollegeinBaytownTexashasseveralrehearsal
andperformancespacesavailabletopresentersandperformers.Manyofthesespaceshaveaccesstosoundreinforcementwhichinter-
actswiththestructure.Inthispresentation,wecompareandcontrasttheamplifiedsystemsandspaces,includingvariableacoustictreat-
ment.Eachspacehasadedicatedpurposethatdeterminestheequipment.
9:25
2aAA5.It’sAllAboutThatBass,DesignofaShowroomforMusic,Comedy,andTheater.BruceC.Olson(OlsonSoundDesign
LLC,8717HumboldtAve.North,BrooklynPark,MN55444,[email protected])andAnaM.Jaramillo(AFMGServicesNorth
AmericaLLC,BrooklynPark,MN)
An 1800 seat casino showroom was designed to provide “state-of-the-art“ acoustics for superstar country and pop performers,
headliningcomedians,andbigproductionBroadwaymusicals.Challengesincludedaverywidestage,acurvedbackwallandaclient
requirementforhiddenloudspeakers.Thispaperwillwalkyouthroughhowthesechallengesweremetwhilemaintainingthehigh-class M
look and feel of the room. We will also show the evolution of the sound system design from the initial system through successive A
upgrades. E.
U
9:45–10:00Break T
a
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10:00
2aAA6.DesignofhallsfortheenjoymentofAmericanmusic.RichardTalaske(TALASKE|SoundThinking,1033SouthBoulevard,
OakPark,IL60302,[email protected])
Designing for contemporary music performanceis more involvedthan achieving the acceptedmid-frequency reverberation time
withintheperformancespace.Whileaccomplishingthecorrectdegreeofreverberanceisessential,thisaloneisnotasufficientcondition
forcreatinganacousticenvironmentsuitablefortheenjoymentofjazz,blues,folk,rock,computer,world,orothernon-symphonicor
non-choralgenresofmusic.Controloflow-pitchedsound,achievingmoderaterunningliveliness,andcreatingamicrophone-friendly
acousticenvironmentarealsoessentialdesigngoals.Asusual,theacousticgoalsshouldbeaccomplishedwhiledevelopingawelcoming
roomdesignwhichoffersintimacybetweenperformersandpatronsandacommunalaudiencesetting.Theseacousticalandsocietal
goalsarediscussedinrelationtocompletedprojectssuchastheEllisMarsalisCenterforMusicinNOLA,TheSidneyHarmanCenter
inDC,andtheOldTownSchoolofFolkMusicinChicago.
10:20
2aAA7.TheGreatOutdoors—Theuniquechallengesimposedbytheoutdoorenvironmentforbothsoundreinforcement,as
wellasacousticalenhancement,ofacousticalandamplifiedmusic.SteveBarbar(E-cousticSystems,30DunbartonRd.,Belmont,
MA02478,[email protected])andJonathanLaney(d&baudiotechnik,Ashville,NC)
Outdoorperformancevenuesepitomizethedefinitionofamulti-purposeperformingartsfacility.However,theydifferinmanyways
fromtheirindoorcounterparts.Theycanbelargerthanmanyarenas,butlackthearchitecturethatbothprovidestheauralcuesofalarge
volume,andinaddition,providesinsulationfromintrusivenoise.Theprogrammingisoftenmorediverse.Onedaythevenuecouldhost
athreeorfouractamplifiedconcert—thefollowingdayasymphonyorchestra,oraweeklongmusicfestival.Weatherisalsoanenor-
mousunknownfactor.Wewilldiscussthechangingnatureofboththeprogramming,aswellaslistenersexpectations,atthesevenues.
Wewillalsodiscussthetechnologiesemployedatseveraloutdoorvenuesthatenablethemtomeettheexpectationsofthemusiciansas
wellastheaudience.
10:40
2aAA8.A240-SeatRecitalSpaceforAmplifiedPerformance.DamianDoria(StagesConsultantsLLC,75FeatherLn.,Guilford,CT
06437-4907,[email protected])andDaveKotch(CriterionAcoust.,JerseyCity,NJ)
Anew240-seatrecitalspacecompletedin2017foraCanadianUniversitywithaBachelorofMusicprogramteachingjazz,rock,
pop,metal,blues,soul,county,electronica,andhiphop.Thearchitecturaldesignbriefrequiredaroomthatcouldaccommodatethe
diverseprogrammingofstudentrecitalsandothermusicsessionsinamodernanaestheticallysatisfyinginteriordesign.Theconceptfor
theroomwasquicklyadoptedbytheOwnerandDesignTeam,butincludedseveralroomacousticschallenges.Thispaperwilldiscuss
theacousticalaccommodationofactivitiesintherecitalspace,alongwithintegrationofthehousesoundsystem,andachronicleofthe
design,value-engineering,construction,andfinalcommissioningprocess.
11:00
2aAA9.Ninetyneversoundedsogood:Guidinganhistoricalauditoriumintothe21stcentury.BrandonCudequestandDavidA.
Conant(McKayConantHoover,5655LinderoCanyonRd.,Ste.325,WestlakeVillage,CA91362,[email protected])
TheSacramentoWarMemorialAuditoriumopenedin1927withascreeningofthesilentfilm,“OldIronsides.”Overitsninety-year
career,the3500-seatauditoriumhashostedeverythingfromShrinersconventionstoShinedownconcerts,RinglingBrotherstoRolling
Stones,andmanymore.Initscurrentstate,theroomisexcessivelyreverberantforamplifiedmusic.Heating,ventilation,andaircondi-
tioningsystemswereupgradedduringthe1990s,albeitwithoutapparentacousticalinput.Streettrafficnoiseisclearlytransmittedvia
acoustically weak windows and stage house doors. McKay Conant Hoover is currently engaged in an acoustical, audiovisual, and
2531 J.Acoust.Soc.Am.,Vol.142,No.4,Pt.2,October2017 174thMeeting:AcousticalSocietyofAmerica 2531
theatricalrenovationofthishistoricvenue.Importantly,theAuditoriummusttemporarilyaccommodateSacramento’stouringBroad-
wayshows,Philharmonic,choral,andballetperformanceswhiletheirmainvenue,TheCommunityCenterTheater,undergoesaseveral
year-longrenovation.Thispaperwilldiscussacousticalchallengesfaced,currentfindings,andhowfactorssuchasill-conceivedpitlifts,
historicalfinishes,limitedstorage,andleadpaintinfluencedourrecommendations.
11:20
2aAA10.Worshipspaceacousticsandarchitectureforcontemporaryserviceswithmodernmusic.RobertC.Coffeen(None,R.C.
CoffeenConsultantinAcoust.,Lawrence,KS66047,[email protected])
Inrelativelyrecenttime,somereligiousworshipfacilitiesarepresentingacontemporaryworshipservicewithmusicthatcanbecon-
sideredmodernanddifferentfromthemoretraditionalmusicproducedbyanorgan,piano,groupsthatemployinstrumentsasusedbya
symphonyorchestra,andbyachoir.Modernmusicforacontemporaryserviceistypicallyproducedbyabandusingelectrickeyboards,
electricandacousticguitars,drums,andsingingbyasolovocalistorbysinginggroupswithallofthemusicelectro-acousticallyampli-
fied.Thus,halls,auditoriums,andsanctuariesforcontemporaryworshipservicesmustgenerallybelessreverberantthanafacilityfor
traditionalmusic,andthesoundreinforcementsystemmustproperlyhandlerelativelyhighlevelmusicandvocals.Italsoseemsthat
architecture forworshipfacilitieswherecontemporaryservices willbe heldhas changedfrommoretraditionalarchitecture tomore
informaldesignswithexposedceilingstructure,movablechairs,etc.ThisalsoseemstoproduceHVACsystemswithhighernoisedue
toexposedsupplyairducts,shortreturnairpaths,androof-topairhandlers.Examplesofandacousticaldataforworshipspaceswith
contemporaryserviceswillbepresented.
TUESDAYMORNING,5DECEMBER2017 SALONE,8:35A.M.TO12:00NOON
Session2aAB
AnimalBioacoustics,SignalProcessinginAcoustics,UnderwaterAcoustics,andAcousticalOceanography:
InMemoryofGeorgeIoup:AcousticsintheGulfofMexicoI
NataliaSidorovskaia,Cochair
Physics,ULLafayette,ULBOX44210,Lafayette,LA70504-4210
DavidK.Mellinger,Cochair
Coop.Inst.forMarineResourcesStudies,OregonStateUniversity,2030SEMarineScienceDr.,Newport,OR97365
Chair’sIntroduction—8:35
InvitedPapers
8:40
2aAB1.GeorgeIoup’scontributiontotheGulfofMexicoacousticresearch:pavingthepathintothefuture.NataliaSidorovskaia
(Phys., UL Lafayette, UL BOX 44210, Lafayette, LA 70504-4210, [email protected]) and Juliette W. Ioup (Phys., Univ. of New
Orleans,NewOrleans,LA)
Bytheendofthe1990s,researchersandregulatorsrecognizedtheneedforunderstandinghowanthropogenicactivitiesimpactceta-
cean’spopulationsintheGulfofMexico.In2000,GeorgeIoupwasoneofthefoundersoftheLittoralAcousticDemonstrationCenter
(LADC),aconsortiumofGulfCoastscientists,withthelong-termgoalofstudyingtheanthropogenicsoundscapesoftheGulfofMex-
icoandtheirimpactonmarinemammals.In2001,LADCwasthefirstteamtocollectlong-termacousticdatarichinspermwhalepho-
nationsfrombottom-mooredautonomousbuoys,technologydevelopedbyNAVOCEANOandadaptedforLADCneeds.Thefirststep
inestablishingabaselinedatabasewastaken.Atthesametime,Georgesparkedtheinterestofbioacousticianswithideasonhowto
employthedifferencesinspermwhalephonationstoidentifyindividualssimilartohowhumansrecognizevoices.LADCendeavors
continuedthroughdesigningacousticsurveystocharacterizethesoundscapesofseismicexplorationarraysandbeingthefirstteamto
recordbeakedwhalesintheGulfofMexicoin2007.Recentadvancesinunderstandingmarinemammalhabitats,studyingtheoilspill
impactontheseanimals,andintroducingnewacoustictechnologieswouldnotbepossiblewithouttheseminalworkofGeorgeIoup.
2532 J.Acoust.Soc.Am.,Vol.142,No.4,Pt.2,October2017 174thMeeting:AcousticalSocietyofAmerica 2532
9:00
2aAB2.Acomparisonofautomatedandmanualtechniquesforacousticallyidentifyingindividualspermwhaleswithchanging
aspect.ChristopherTiemann(R2SonicLLC,5307IndustrialOaksBlvd.,Ste.120,Austin,TX78735,[email protected])
AsshownbyhisextensivehistoryofresearchintheGulfofMexico,Dr.GeorgeIouphadafascinationwiththemarinemammals
thatlivedthere.Inparticular,hequestionedwhetherindividualwhalesofagivenspeciescouldidentifyeachotheracoustically,andby
extension,whetherhumanscoulddothesame.Georgewasanearlyproponentinthecommunityofadvancingautomatedmethodsfor
discriminatingindividualodontocetesbyanalyzingtheclickstheymake,aproblemthatgrowsconsiderablymoredifficultwhenmulti-
pleanimalsareclickingsimultaneously.IhadthegoodfortuneofbeingabletoexplorethissubjectwithGeorgeinanindependent
researchprojectthatmaynothavebeenwidelyreportedbutwasimportantandenjoyableforusnonetheless.Georgerealizedquickly
thatconventionalmethodsforautomatedgroupingofclicksfromthesameclicktrainwerefailingbecausetherewasnoguaranteeof
clickstructureconsistencyasananimalchangedaspectrelativetoareceiver.Anautomatedmethodforgroupingspermwhaleclicks
basedonacrosscorrelationmethodoriginallyappliedtodolphinclicksprovidedtheneededflexibilitytofollowanevolvingclickshape
asshownbytheclosematchbetweenGeorge’sautomatedresultsandmymanuallygeneratedgroupings.
9:20
2aAB3.Modelingasacomplementarytooltoacousticdataforunderstandingtheimpactofenvironmentaldisastersonmarine M
A
mammals.AzmyS.Ackleh,RossChiquet,TingtingTang,AmyVeprauskas(Mathematics,Univ.ofLouisianaatLafayette,P.O.Box
41010,Lafayette,LA70504,[email protected]),HalCawell(Univ.ofAmsterdam,Amsterdam,Netherlands),NataliaSidorovskaia E.
U
(Phys.,Univ.ofLouisianaatLafayette,Lafayette,LA),andBaolingMa(MillersvilleUniv.,Millersville,PA)
T
Thisstudyisfocusedonhowenvironmentaldisasters,suchastheDeepwaterHorizonoilrigexplosionin2010,affectthedynamics a
2
ofmarinemammalpopulations,particularlyspermwhalesandbeakedwhales,intheNorthernGulfofMexico.Webrieflydescribehow
modelingtechniquesareusedtoestimatedensitiesofmarinemammalsusingpassiveacousticdata.Wethendevelopamatrixmodelto
examinethepossiblelong-termeffectsofadisaster.Weconsidercasesinwhichtheeffectsofadisturbanceresultinreductionsineither
survival(lethalimpacts)orfecundity(sublethalimpacts).Thismodel,combinedwithdemographicstochasticity,allowsustostudythe
long-termrecoveryprocessfollowinganenvironmentaldisaster.Inparticular,recoveryprobabilitiesandrecoverytimesofthepopula-
tionarecomputed,andformulasarederivedtocomputethesensitivityoftherecoverytimetochangesinpropertiesofthepopulationor
theenvironmentaldisturbance.Wethenextendthemodelingmethodologytoconsiderhowmarinemammalsmaybeaffectedbythe
responseoftheirpreypopulationtoadisturbance.Ouranalysishighlightsthedifficultyofprojectingimpactsandrecoveryintheab-
senceofdetaileddemographicdata,andthevalueofpopulationmodelsinexploringscenariosandidentifyingimportantprocessesand
generalrelationships.[ThisresearchwasmadepossibleinpartbyagrantfromTheGulfofMexicoResearchInitiative.]
9:40
2aAB4.PassiveacousticmonitoringintheNorthernGulfofMexicousingoceangliders.DavidK.Mellinger,SharonL.Nieukirk,
SaraL.Heimlich,SeleneFregosi(Coop.Inst.forMarineResourcesStudies,OregonStateUniv.,2030SEMarineSci.Dr.,Newport,
OR 97365, [email protected]), Elizabeth T. K€usel, Martin Siderius (Northwest Electromagnetics and Acoust. Res.
Lab.,PortlandStateUniv.,Portland,OR),andNataliaSidorovskaia(Dept.ofPhys.,Univ.ofLouisianaatLafayette,Lafayette,LA)
AlthoughGeorgeIoupdidnotuseoceanglidersforpassiveacousticmonitoring,herecognizedtheirvalueasplatformsforPAM
andencouragedotherstousethem.TheyfunctionwellasPAMplatformsbecause(1)theymoveslowly,minimizingflownoise;(2)
theyhavenopropellerorcontinuouslyrunningmachinery,minimizingmotornoise;(3)theycollectacousticdatanearlycontinuously;
(4)theytraversetheupperwatercolumneveryfewhours,measuringtemperatureandsalinityasneededforcalculatingsoundspeedpro-
filesandenablingaccuratemodelingoflong-rangeacousticpropagation;(5)theycancoverhundredstothousandsofkilometersindis-
tanceduringadeployment,enablingthemtomonitoralargeareaand/orrepeatedlymonitorasmallerarea;and(6)somemodelscan
diveto1000m,thedepthatwhichsomedeep-divingcetaceans—spermandbeakedwhales,frequenttargetsofPAMoperations—forage
andvocalize.TwomodelsofglidersequippedwithpassiveacousticrecordingsystemsweredeployedintheNorthernGulfofMexicoin
thesummersof2015and2017tostudycetaceanoccurrenceandbehavior.Here,wesummarizethevirtuesandhazardsofgliderPAM,
anddescribeacousticdetectionandclassificationofcetaceansintheserecordings.[ResearchsupportedbyGoMRI.]
10:00
2aAB5.Echolocationforrestoration:OdontocetemonitoringintheGulfofMexico.KaitlinE.Frasier,RebeccaCohen,JenniferS.
Trickey,SeanM.Wiggins,AlbaSolsonaBerga(ScrippsInst.ofOceanogr.,8622KennelWay,LaJolla,CA92037,[email protected]),
MelissaSoldevilla,LanceGarrison(ProtectedResourcesDiv.,NOAASEFSC,Miami,FL),SimoneBaumann-Pickering,andJohnHil-
debrand(ScrippsInst.ofOceanogr.,LaJolla,CA)
Inthelate1990s,GeorgeE.IoupbeganstudyingecholocationclicksasameansofunderstandingmarinemammalsintheGulfof
Mexico(GOM).Healsoledoneofthefewresearchprogramsfocusedonpelagicspeciesinthischronicallyimpactedregionintheyears
precedingtheDeepwaterHorizonoilspill.Today,passiveacousticmonitoring(PAM)isoneoftheprimarytoolsusedtostudythe
nearly20pelagicodontocetespeciesfoundintheGOM,includingspermwhales,beakedwhales,dolphins,andKogiaspecies.Since
2010,PAMdeviceshavebeendeployednearlycontinuouslyintheregion,drivenbyanurgentneedtounderstandthelong-termeffects
of both acute and chronicanthropogenic impacts onGOM marine mammal populations. Recent advancesfueled by robust, reliable
PAMtechnologiesincludethedevelopmentofmulti-yeartimeseriesdocumentingchangesinspeciesdensitiesacrosscontinentalshelf
andslopehabitats,differentiatingGOModontocetespeciesbasedonecholocationclickproperties,andleveraginglong-termdatasetsto
understandtheinfluenceofhabitatvariabilityonoffshorespeciesdistributions.ThesecapabilitiesareprovingPAMisindispensableas
anobservationmethodfordamageassessment,decisionsupport,andrestorationactivitiesformarinemammals,especiallyinaccessible
pelagicpopulations.
10:20–10:40Break
2533 J.Acoust.Soc.Am.,Vol.142,No.4,Pt.2,October2017 174thMeeting:AcousticalSocietyofAmerica 2533
10:40
2aAB6. AirborneelectromagneticprofilingintheGulfofMexico.KennethW.Holladay(MathematicsDept.,Univ.ofNewOrleans,
NewOrleans,LA70148,[email protected])
First, I will give an overview of the research on Airborne Electromagnetic Profiling (AEM) by the University of New Orleans
(UNO)groupthatincludedGeorgeIoup.Thestandardtechniquesoferrorcorrection,calibration,modeling,inversemethods,interpola-
tion,andsmoothingwereusedtoconvertrawprofilerdataintomeaningfuldataandusefulproducts.AsapartofaNASAEPSCoRpro-
ject,thegroupappliedlayermodelstoAEMdatatomeasureshallowwaterbathymetryandwatercolumnstratificationintheGulfof
MexicoandcoastalnearsurfacegeomorphologyintheBaratariabasinofLouisiana.Inthesecondpartofthetalk,Iwillsketchthehis-
toryoftheUNOEngineeringandAppliedSciencedoctoralprogramandGeorgeIoup’slargeroleinit.
11:00
2aAB7.Lognormalbubblesizedistributions.JeraldW.Caruthers(29PecanDr.,LongBeach,MS39560,[email protected])
Inthestudyofoceanicbubblesbasedonempiricalacoustics,thedistributionsamongthesizesaretypicallyrepresentedbypower
lawswithnegativeslopesasconvenientdescriptorsofdatainlog/logformat.However,powerlawsdonotaddressthefactthatasbubble
sizesapproachzerotheirnumbersmustapproachzero.Multiplepowerlaws,includinga horizontalsegmentprecededbyapositive
power-lawsegmentandfollowedbytheexpectednegativepower-lawsegment,havebeenusedtorecognizeandmitigatethisproblem.
Althoughnotuniversallyadoptedasyet,severalacousticresearchershavesuggestedthatatleastsomeoceanicbubbledistributionsare
moreappropriatelyrepresentedbylognormaldistributions.In1941,A.N.Kolmogorovusedthe1922workofL.R.Richardsoncon-
cerningastochasticdownwardcascadeofrandomsizesofturbulentvorticesthatasymptoticallyresultinlognormaldistributionsofvor-
tices.Thiscurrentpaperusessuchacascadeofvorticestobeginadownwardcascadeofbubblessizescausingcascadingshearforceson
largebubblesthatwerecreatedbybreakingwaves.Incombinationwiththisdecreasingeffectofturbulentshearonthesefragmenting
bubbles,thedownwardcascadeofbubblessizesoverlapsandcontinueswithastrengthenedpartial-pressureeffectoneverincreasing
surfacetensioncausedbytheirdiminishingsizes.Issuesassociatedwiththisapproach,suchassumminglognormalgeneratorsandinter-
mittency,willbediscussed.
11:20
2aAB8.InmemoryofGeorgeE.Ioup:FounderoftheUniversityofNewOrleansphysicsprogramattheStennisSpaceCenter.
StanleyA.Chin-BingandJulietteW.Ioup(Dept.ofPhys.,Univ.ofNewOrleans,2000LakeshoreDr.,NewOrleans,LA70148,chin-
[email protected])
Inthelate1970s,twoU.S.NavyorganizationswereformedandlocatedinanareanowknownastheStennisSpaceCenter,Missis-
sippi,locatednearly50milesEastoftheUniversityofNewOrleans(UNO).Thesetwoorganizationsemployednearly1500scientists
andtechnicianswhoneededadvancedtraininginphysics,specificallycoursesinvolvingacousticsandsignalprocessing.In1982,Pro-
fessorGeorgeE.IouptooktheinitiativetohaveUNOdevelopandteachthesecourseson-siteattheStennisSpaceCenter.Inthefollow-
ing33years,nearly20differentgraduatelevelcoursesweredevelopedandtaughtmultipletimesattheStennisSpaceCenter.Itwas
possibletotakeallthenecessarycoursesneededfortheMastersandPh.D.degreeson-site,whilemaintainingfull-timeemployment.
UnderProfessorIoup’sleadership,severaldozenNavyscientistsreceivedadvanceddegreesfromtheUniversityofNewOrleans,and
manymorereceivedspecifictrainingthatenhancedtheirprofessionalcareers.Thispresentationwillhighlightthededicatedeffortsand
successesofGeorgeIoupincreatingtheUNOphysicsprogramattheStennisSpaceCenter,MS.
11:40
2aAB9.Relationshipbetweenheadsizeandbiosonartransmitandreceivebeamsinodontocetes.WhitlowAu(Univ.ofHawaii,
P.O.Box1106,Kailua,HI96734,[email protected])
Theuniqueshapeofadolphinhead,thedifferentspeciespecificshapeandtheinternalheadstructuresuggestaverycomplexpropa-
gationmechanismforthebiosonarsignalstotravelfromthephoniclipsintothewater.Despitethesefactors,acircularplanaraperture
oftheappropriatediametercanproduceatransmissionbeamthatresemblesthecorrespondingbeamofadolphin.Inthesimilarmanner,
thereceptionprocessisalsoverycomplexandnotcompletelyunderstood.Onceagain,despitethecomplexityinvolvingthereception
ofbiosonarechoes,asimplecircularplanarapertureoftherightdiametercanhaveareceivingbeamthatapproximateorresemblethe
receivingbeamofodontocetes.Forbothtransmissionandreceptionofbroadbandbiosonarsignals,thesizeoftheheadcomparedtothe
wavelengthofthesignalwilldeterminethedegreeofdirectionalityofthebeamsinodontocetesinasimilarmannerasaplanartrans-
ducer.BeampatterndatafromTursiopstruncates,Delphinapterusleucas,Pseudorcacrassidens,andPhocoenaphocoenawillbeused
todemonstratetherelationshipbetweenheadsizeanddirectionalityforthetransmitsignal.ReceivingbeampatterndatafromTursiops
truncatesandPhocoenaphocoenawillbeusedinasimilarmannerasforthetransmitbeam.
2534 J.Acoust.Soc.Am.,Vol.142,No.4,Pt.2,October2017 174thMeeting:AcousticalSocietyofAmerica 2534
TUESDAYMORNING,5DECEMBER2017 BALCONYM,8:25A.M.TO12:00NOON
Session2aBA
BiomedicalAcoustics,StructuralAcousticsandVibration,andPhysicalAcoustics:WavePropagation
inComplexMedia:FromTheorytoApplicationsI
GuillaumeHaiat,Cochair
MultiscaleModelingandSimulationLaboratory,CNRS,LaboratoireMSMS,Faculte(cid:2)desSciences,UPEC,
61avenuedugaldeGaulle,Creteil94010,France
PierreBelanger,Cochair
MechanicalEngineering,Ecoledetechnologiesuperieure,1100,NotreDameOuest,Montreal,
M
QCH3C1K/,Canada
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Chair’sIntroduction—8:25 T
a
2
InvitedPapers
8:30
2aBA1.Parity-timesyntheticphononicmedia.JohanChristensen(UC3MMadrid,UC3M,Madrid28935,Spain,johan.christensen@
uc3m.es)
Classicalsystemscontainingcleverlydevisedcombinationsoflossandgainelementsconstituteextremelyrichbuildingunitsthat
can mimic non-Hermitian properties, which conventionally are attainable in quantum mechanics only. Parity-time (PT) symmetric
media,alsoreferredtoassyntheticmedia,havebeendevisedinmanyopticalsystemswiththegroundbreakingpotentialtocreatenon-
reciprocalstructuresandone-waycloaksofinvisibility.Here,wedemonstrateafeasibleapproachforthecaseofelasticitywherethe
mostimportantingredientswithinsyntheticmaterials,lossandgain,areachievedthroughelectricallybiasedpiezoelectricsemiconduc-
tors[1].Westudyfirsthowwaveattenuationandamplificationcanbetuned,andwhencombined,cangiverisetoamechanicalPTsyn-
theticmediawithunidirectionalsuppressedreflectance,afeaturedirectlyapplicabletoevadingsonardetection[2].[1]J.Christensen,
M.Willatzen,V.R.Velasco,andM.-H.Lu,Phys.Rev.Lett.116,207601(2016).[2]S.A.Cummer,J.Christensen,andA.Alu,Nature
Rev.Mater.1,Articlenumber:16001(2016).
8:50
2aBA2.Beyondthesingle-scatteringassumptionforanalysisofdiffuseultrasonicscatteringexperiments.JosephA.Turnerand
NathanialMatz(Mech.andMater.Eng.,Univ.ofNebraska-Lincoln,W342NebraskaHall,Lincoln,NE68588-0526,[email protected])
Characterizationofdiffuseultrasonicscatteringischallengingbecauseaccuratemodelsrequireassumptionsaboutthedegreeofscat-
tering.Mostpreviousresearchhasfocusedonthesingle-scatteringregimeinwhichraysareassumedtoscatteronlyoncebeforedetec-
tion. In this presentation, scattering effects beyond single scattering are examined with a focus on polycrystalline materials. The
contributionofthesecondscatteringwithintheresponseisquantifiedwithrespecttomeasurementparametersandsampleproperties.
Theresultsshowthatsingle-scatteringmodelsareappropriateforweaklyscatteringmaterials,suchasaluminum,forawiderangeof
experimentsandgrainsizes.However,strongerscatteringmaterialsarepredictedtohavesignificantcomponentsbeyondsingle-scatter-
ingforcertainmeasurementparametersevenintheRayleighregime.Experimentalresultsforasteelalloyareusedtoverifymodelpre-
dictions.Theexperimentalworkshowsthedomainforwhichthedoubly-scatteredresponsebecomessignificantaswellasthelimitation
atwhichthedoublescatteringmodelisnolongerapplicable.Theresultscanbeusedtopredicttheapplicablefrequencyrangeforeach
levelofscatteringforagivenexperimentalconfiguration.Finally,theimpactofthehigher-orderscatteringisdiscussedwithrespectto
thedetectionofdefectswithinaheterogeneousmedium.
9:10
2aBA3. Acoustic propagation in a fractal network of scatterers. Vincent Gibiat, Etienne Bertaud (Toulouse Univ., 118 Rte. de
Narbonne, Toulouse 31400, France, [email protected]), MArie-Fraise PONGE (I2M, Bordeaux Univ., Bordeaux, France),
andXavierJacob(ToulouseUniv.,Toulouse,France)
Fractalnetworks,builtonCantorset,FibonacciseriesorSierpinskysetsarecharacteristicsofastructuralorganizationbetweenperiodic
andrandom.Ontheotherhand,theyhavebeenprovedtobeagooddescriptorofirregularsystemsasthewellknowndescriptionofBrit-
tanycoasts.Suchsystemscanbeseenasirregularboundaries,asinthecaseofirregularcoasts,whilethewaveequationsarestillusable
insidethesesboundaries.Alongtheboundaries,wavelocalizationispossible.Anothercaseisthatwhereboundariesareregularwhilethe
organization ofthe material where waves are propagatingcarriesthe fractality.Wavepropagationonsuchsystems canbeconsidered
throughtheaspectofmultiplescattering,andon1Dsystemsaswellon2DsystemsbuiltonCantororsierpinskiset,itispossibletoshow
2535 J.Acoust.Soc.Am.,Vol.142,No.4,Pt.2,October2017 174thMeeting:AcousticalSocietyofAmerica 2535
theexistenceoflocalizedmodes.Onthecontrarytothepreviouscase,localizationarisesnotalongtheboundariesbutinsidethepropagat-
ingmedium.Lesscommonorganizationofscatterers,forinstance,thosebuiltonFibonacciseriescanalsobecomparedtoperiodicorgani-
zationsaswellasrandomones.Variousexampleswillbeshownonexperimentalmaterialasontheoreticalornumericalexamples.
9:30
2aBA4.Relationshipbetweenultrasoundscatteringandacousticimpedancemapsinsparseanddenserandommedia.Jonathan
Mamou(F.L.LizziCtr.forBiomedicalEng.,RiversideRes.,156WilliamSt.,9thFl.,NewYork,NY10038,jmamou@riversidere-
search.org),KazukiTamura(GraduateSchoolofEng.,ChibaUniv.,Chiba,Japan),DanielRohrbach(F.L.LizziCtr.forBiomedical
Eng.,RiversideRes.,NewYorkCity,NY),TadashiYamaguchi(Ctr.forFrontierMedicalEng.,ChibaUniv.,Chiba,Japan),andEmilie
Franceschini(LaboratoiredeM(cid:2)ecaniqueetd’Acoustique,AixMarseilleUniversit(cid:2)e,CNRS,CentraleMarseille,Marseille,France)
Quantitative modeling of ultrasound scattering from soft tissues has been used extensively to characterize soft tissues. In this
approach,tissuesaretypicallymodeledasarandommediumcontainingscatterersofspecificshapes,acousticproperties,andspatial
arrangements.Underplane-waveinsonificationandassumingweakscattering(i.e.,Bornapproximation),thebackscatteredcoefficient
(BSC)ofsucharandommediumisfullydescribedbythepowerspectrumofitsthree-dimensional(3D)impedancemap(ZM).Atwo-
dimensional(2D)ZMcanbeobtainedbyscanningacousticmicroscopy(SAM)appliedtothintissuesectionsusingveryhigh-frequency
ultrasound(>100MHz).Underisotropicassumptions,2DZMscanpredicttheBSCaccurately;nevertheless,inthecaseofdensemedia,
wherethelocationsofthescattererscanbecorrelated,someofthetheoreticalassumptionsfail,whichrequiresintroductionofthestruc-
ture-factormodel(SFM).Usingexperimentalandsimulateddata,thispresentationwillreviewcomputationoftheBSCfromultrasound
measurements,theworkingprinciplesofSAM,theuseof3DZMsand2DZMstopredicttheBSC,SFMestimationfrom2DZMsand
3DZMs,andtheuseofSFMforBSCcomputationandtissuecharacterization.
9:50
2aBA5.Simulationofguidedwavesinlayeredfluid/viscoelastic/poroelasticmediausingsemi-analyticalfiniteelementmethod.
Vu-HieuNguyen(Univ.ofParis-Est,61Ave.dug(cid:2)en(cid:2)eraldeGaulle,Creteil94010,France,[email protected])
Understanding oftheultrasoundtransmissioninfunctionallygradedstructuresmaterialsisofgreatinterestinmanyengineering
applicationssuchasgeophysics,biomedicaldiagnostics,aircraft,andautomobile.Thispaperwillpresentacomputationalmethodand
itsimplementationproceduretostudythewavepropagationprobleminmultilayerstructuresmadefromacombinationoffluid,aniso-
tropicviscoelastic,andporoelasticmaterials.TheporoelasticmaterialisdescribedbyusingtheBiottheory.Thedevelopedapproachis
basedontheSemi-analyticalFiniteElementMethod(SAFE),whichonlyrequiresthediscretizationofthecross-sectionofthestructure.
Forthefiniteelementsolver,high-orderspectralelementhasbeenused,showingasignificantimprovementofthecomputationaleffi-
ciencycomparedtotheuseofconventionalhigh-orderelements.Numeralvalidationinbothtimeandfrequencydomainsshowthatthe
proposedapproachisefficienttoinvestigatethetransientresponseaswellasthedispersionoflayeredmedia.Someresultsinthecontext
ofquantitativeultrasoundaxialtransmissiontechniquesforassessingpropertiesofcorticallongboneswillalsobepresented.
10:10–10:25Break
10:25
2aBA6.Nonlinearcodawaveinterferometry:Characterizingdamage incomplexsolids.VincentTournat(LAUM,CNRS,Uni-
versit(cid:2)eduMaine,Av.O.Messiaen,LeMans72085,France,[email protected])
Inthistalk,wereportresultsonthenonlinearinteractionsofultrasoniccodawaves,inreverberatingormultiplescatteringmeso-
scopicsolidmedia.Usingthemethodofcodawaveinterferometry(CWI),weanalyzetheeffectofmixingacodawavewithanaddi-
tional lower frequency pump wave. The extracted CWI parameters, known to be highly sensitive to small geometric or elastic
modificationsofthetestedmedium,areshowntobepump-amplitudedependentandtocapturefinelytheresultsofthenonlinearinterac-
tions.Althoughnonlinearself-actioneffectswithcodawaveshavebeenreportedinunconsolidatedgranularmedia,theyaredifficultto
implementincrackedsolidsorconcrete.Instead,thereportednonlinearCWIclassofmethods(NCWI)showsrobustness,ahighsensi-
tivity,andhasbeenappliedsuccessfullytovariouscomplexmediaandstructures.Weshowthroughseveralexampleson«model»
media(crackedglassplates)andonconcretestructures,thatNCWIcanbeusefulforthenondestructiveevaluationofcomplexsolids
thatarestronglyscatteringatusualprobingfrequencies.Preliminaryresultsandprospectsinnonlinearelasticpropertiesimagingand
quantitativeevaluationwithNCWIarediscussed.
10:45
2aBA7.Propagationofultrasonicwavesincomplexmedia:InvestigationofcodawavetechniqueandtraditionalpolarandC-
scanimaging.NicoF.Declercq,LyndaChehami(Mech.Eng.,UMIGeorgiaTech–CNRS2958,GeorgiaTechLorraine,2rueMar-
coni, Metz 57070, France, [email protected]), Pascal Pomare`de (LEM3, UMR CNRS 7239, Art et M(cid:2)etiers Paris Tech,
Metz,France),OthmaneEz-Zahraouy,EsamAhmedMohammed(Mech.Eng.,UMIGeorgiaTech–CNRS2958,GeorgiaTechLor-
raine,Metz,France),andFodilMeraghni(LEM3,UMRCNRS7239,ArtetM(cid:2)etiersParisTech,Metz,France)
Adiscussionofnondestructivetechniquesispresentedfortheinvestigationofcomplexmedia,withafocusoncompositesamples.
Traditionally,oneappliesultrasonicC-scans,orpolarscans,whichareeasytoimplementandtointerpret.However,inmanyrealistic
cases,itisimportanttousemoresophisticatedapproachesasC-scansoftendonotrevealanyusefulinformation.Typically,theearly
partofreceivedsignalsisusedtoextractinformation,whereasthelaterpartisconsideredeitherasnoiseorasauselesscodawaveasin
musicalacoustics.Nevertheless,itappearsthatthecodapartcarriesusefulinformationaboutthemedium,andtherefore,itisimportant
toexploretechniquestoextractthatinformation.Inaddition,itturnsoutthatthecodaisverysensitivetomaterialpropertiesanddamage
asthosesoundwavesinteractlongerwiththematerialthanearlyarrivalwaves.First,earlierresultswillbeshownwhichcompareexper-
imentalpolarscanswithnumericalsimulations,then,forthesamesamples,codawaveresultswillbepresentedtoshowtheeffectof
damageonthecompositesamples.Themaindamageindicatoristhechangeinrelativewavevelocitywhichiscausedbythedamage.
2536 J.Acoust.Soc.Am.,Vol.142,No.4,Pt.2,October2017 174thMeeting:AcousticalSocietyofAmerica 2536
ContributedPaper
11:05 possibilityofcharacterizinganisotropicmaterials.Recentprogressinultra-
sound tomography using a circular array of transducers enabled velocity
2aBA8.Ultrasoundtomographyofmaterialswithhighsoundspeedcon-
mappingofmaterialswithhighsoundspeedcontrastrelativetotheback-
trast.TimotheFalardeauandPierreBelanger(Mech.Eng.,EcoledeTech-
ground.Inthisstudy,animageofacousticpropertiesofatitaniumrodsub-
nologieSup(cid:2)erieure,1100RueNotre-DameOuest,Montreal,QCH3C1K3,
merged in water was obtained using bent ray time-of-flight tomography.
Canada,[email protected])
Theexperimentswereperformedonacirculararrayultrasonictestbenchat
Non-destructiveevaluationofmaterialsusingultrasoundsisfrequently 2MHzfrequencyon322transductionpoints.A2Dfiniteelementmodelof
usedinindustryasawaytocharacterizematerialpropertiesandtolocate wavepropagationthroughwaterandtitaniumwasdevelopedinordertoval-
defects. Imaging methods based on back propagation of echo signals are idate experimental results. Finite element reconstruction matched experi-
limitedtoreconstructionoflowspatialfrequency.Ultrasounddiffractionto- mentalresultswithina10%errorforgeometryandvelocity.
mography is a transmission-based imaging method which gives the
InvitedPapers M
A
E.
U
T
11:20 a
2
2aBA9.Recentadvancesinresonantultrasoundspectroscopy(RUS)forthemeasurementofthestiffnesstensorofanisotropic
andattenuativematerials.QuentinGrimal(BiomedicalImagingLab.,SorbonneUniversit(cid:2)es-Universit(cid:2)ePierreetMarieCurie,15rue
del’(cid:2)ecoledem(cid:2)edecine,Paris75006,France,[email protected])
TheelasticitytensorofasmallsampleofanisotropicmaterialcanbeadvantageouslydeterminedwithResonantUltrasoundSpec-
troscopy(RUS).InRUS,resonantfrequenciesofasamplearemeasured,andcomputedfrequenciesofanumericalmodelofthesample
arefitted,yieldingthestiffnesstensor.RUSwasdevelopedinthe1990s,butuntilrecently,itwasinpracticelimitedtomeasuremateri-
alswithahighqualityfactor.Wehaverecentlyadaptedthemethodtomeasureattenuativematerialssuchasplasticsandhardbiological
tissues(boneandtoothtissues)withatypicalqualityfactorofabout25.OurstrategycombinesBayesianmethodstoretrieveoverlapped
resonantpeaksintheRUSspectraandtosolvetheinverseproblemusingalimitednumberofresonantfrequencies.Themethodallows
aquasi-automatedprocessingofRUSspectrawhereitisnotnecessarytoknowapriorithepairingbetweenmeasuredandcomputedfre-
quencies.Inthelastyears,wehaveextensivelyusedRUStodocumenttheanisotropicelasticpropertiesofhumanboneandweexplored
applicationinadditivemanufacturing.
11:40
2aBA10.Optical-resolutionphotoacousticimagingwithspeckleillumination.EmmanuelBossy(LIPhy,Universit(cid:2)eGrenobleAlpes/
CNRS,LIPhy,140ruedelaPhysique,Saint-Martind’He`res38400,France,[email protected])
Conventionalapproachesforoptical-resolutionphotoacousticmicroscopygenerallyinvolvesrasterscanningafocusedspotoverthe
sample.Here,weshowthatafull-fieldilluminationapproachwithmultiplespeckleilluminationcanalsoprovidediffraction-limitedop-
tical-resolutionphotoacousticimages.Twodifferentproof-of-conceptsaredemonstratedwithmicro-structuredtestsamples.Thefirst
approachfollowstheprincipleofghostimaging[1],andisbasedhereonsolvingalinearinverseproblemundersparsityassumptions:
theobjectisreconstructedthroughapseudo-inversecomputationofareferencematrixmadeofspecklepatternsmeasuredduringacali-
brationstep.Thesecondapproachisaspecklescanningmicroscopytechnique,whichadaptsthetechniqueproposedinfluorescencemi-
croscopybyBertolottietal.[2]:inourwork,spatiallyunresolvedphotoacousticmeasurementsareperformedforvarioustranslationsof
unknownspecklepatterns.Becausespecklepatternsnaturallyappearinmanyvarioussituations,includingpropagationthroughbiologi-
caltissueormulti-modefibers,speckle-illumination-basedphotoacousticmicroscopyprovidesapowerfulframeworkforthedevelop-
mentofnovelreconstructionapproaches,well-suitedtocompressedsensingapproaches.[1]Katzetal.,“Compressiveghostimaging,”
Appl.Phys.Lett.95(13),2009.[2]Bertolottietal.,“Non-invasiveimagingthroughopaquescatteringlayers,”Nature491(7423),2012.
2537 J.Acoust.Soc.Am.,Vol.142,No.4,Pt.2,October2017 174thMeeting:AcousticalSocietyofAmerica 2537
TUESDAYMORNING,5DECEMBER2017 BALCONYN,9:00A.M.TO12:00NOON
Session2aEA
EngineeringAcoustics:ThermophoneTransduction
ThomasR.Howarth,Cochair
NAVSEADivisionNewport,1176HowellSt.,B1346R404A,Newport,RI02841
AndrewR.Barnard,Cochair
MechanicalEngineering-EngineeringMechanics,MichiganTechnologicalUniversity,815R.L.SmithMEEMBuilding,
1400TownsendDrive,Houghton,MI49931
Chair’sIntroduction—9:00
InvitedPapers
9:05
2aEA1.Platinumfilmstocarbonnanostructures:Thehistoryofthethermophonetransducer.AndrewR.BarnardandMahsa
Asgarisabet(Mech.Eng.-Eng.Mech.,MichiganTechnolog.Univ.,815R.L.SmithMEEMBldg.,1400TownsendDr.,Houghton,MI
49931,[email protected])
Thethermophoneisadevicewhichcreatessoundusingrapidheatoscillationsonitssurface.Thisresultsinathinandlightweight
loudspeakerwithnomovingparts.Braunwasthefirsttoaddressthisphenomenoninthelate1800s.ArnoldandCrandalldevelopedthe
firsttheoryandcorrelatedexperimentalresultsin1917.Unfortunately,thematerialsnecessarytomakeanefficientthermophonedidnot
existintheirtime.In2008,Xiaorediscoveredthethermophoneeffectusingcarbonnanotubethinfilms,amaterialmuchbettersuitedto
efficientthermophones.Sincethenmanyresearchershavebeenworkingondevelopingthermophonetechnologyusingcarbonnano-
structuresincludingnanotubes,nanofibers,andgraphene.Thistalkwillcoverthehistoryofthethermophonefromitsearlydaysthrough
todayandgiveabroadoverviewoftheapplicationareasforthistechnology,whichspanfromunderwatertransducerstoconsumerelec-
tronicsandautomotiveapplications.
9:25
2aEA2.Thermoacousticsoundprojector:Beyondthefundamentalefficiencyofcarbonnanotubes.AliE.Aliev(AlanG.MacDiar-
midNanotechInst.,Univ.ofTexasatDallas,P.O.Box830688,BE26,Richardson,TX75083,[email protected])
Advancesinthermophonetransductionfromtheperspectiveofnovelnanostructuredmaterials,devicedesign,andsignalprocessing
willbepresented.Thecomparisonofstudied2Dand3Dnetworksofnanostructuredmaterialswithaerogelstructureswillbegiven.The
energyconversionefficiencyofencapsulatedthermoacousticdevicesexcitedbyshortpulseswithvaryingdutycycle,shapeofpulse,
andcarriersignalfrequencywillbeanalyzedforavarietyoffabricateddevices.Iwillprovideanextensiveexperimentalstudyofpulse
excitationindifferentthermodynamicregimesforfreestandingcarbonnanotubesheetswithvaryingthermalinertias(single-wall,multi-
wallwithvaryingdiameters,andnumberofsuperimposedsheets)invacuumandinair.Theexperimentalobservationsarerationalized
withinabasictheoreticalframework.Theacousticalandgeometricalparametersprovidingfurtherincreaseinefficiencyandtransduc-
tionperformanceforopenandclosedresonantsystemswillbediscussed.[ResearchsupportedbyONR,GrantNo.:N00014-17-1-2521.]
9:45
2aEA3.Thefabricationandcharacterizationofnanocarbonfoamsfortheirutilizationinthermoacousticdevice.MeiZhang,Paul
Wolmarans(High-PerformanceMater.Inst.,FloridaStateUniv.,IME,FAMU-FSUCollegeofEng.,2525PottsdamerSt.,Tallahassee,
FL32310,[email protected]),andAliE.Aliev(A.G.MacDiarmidNanoTechInst.,Univ.ofTexasatDallas,Richardson,TX)
Thermo-acoustic(TA)soundgeneration(thermophone)isanon-resonanttechniquewhereelectricalenergyisconvertedtosound
wavesthroughJouleheatingofaresistor(TAheatsource)withoutanymechanicalvibration,thusallowingforawidebandoperation.It
isclearthatthematerialandthestructureoftheresistorplayanimportantroleontheperformanceofthethermophone.Recently,ther-
mophonetransducersfabricatedfromnanoscalematerialsholdthepromiseofanewtransducertechnology.Transducersmadefrom
thesenanomaterialsoperateoverabroadfrequencyrangeandcanbedesignedtobelighterandthinnerthancompetingtechnologies.
Here,wereporttheTAheatsourceusingnanocarbonfoams.Nanocarbonfoamsarecarbonnanotubes(CNTs)basedallcarbonporous
materials.Theyhaveahierarchicallyporousstructureandtheporesizeandporositycanbetunedeasilyduringthefabricationprocess.
ThefoamsconsistofhighlyporousconductiveCNTnetworks.Theyarefreestanding,flexible,andmechanicallyrobustinvariousenvi-
ronments.Itisdemonstratedthatthefoamscanbeusedaselasticallycompressible,flexibleTAheatsource.Thedetailedfabrication
process,themorphologyofthefoams,theirthermalandelectricalproperties,andtheirperformanceasthermophonetransducerswillbe
presented.
2538 J.Acoust.Soc.Am.,Vol.142,No.4,Pt.2,October2017 174thMeeting:AcousticalSocietyofAmerica 2538
10:05
2aEA4.Thermophonesforsonarapplications.NathanaelK.Mayo,ChristianSchumacher,DonaldCox,JeffreyE.Boisvert,JohnB.
Blottman, and Thomas R. Howarth (Naval Undersea Warfare Center: Newport, Naval Undersea Warfare Ctr., Div. Newport, 1176
HowellSt.,Newport,RI02841-1708,[email protected])
Thermophonesareelectricallydriventhermoacoustic soundprojectorswhichhavehistoricallybeenused as a primary sourceof
sound.Thermophoneshaveasoundspectrathatarelargelydeterminedbytheirhousingandsupportandefficienciesthataredetermined
bythedevice’sabilitytomaintainadynamictemperaturegradientacrossagaseouslayersurroundingthethinheatingelement.Anum-
beroffactorsmakethermophonesanattractivetechnologyforunderwateruseincludingtherelativeeaseandlowcostofproduction,the
largethermalreservoirprovidedbythesurroundingaquaticenvironment,andtheabilitytotunethespectraoverabroadrangeoffre-
quencies.Wepresentcalibratedacousticunderwatertestsperformedonthermophoneswhichdemonstratethepotentialforanewclass
ofsonartransducers.Small,6.35cmdiameter,inertgasfilledlaminatepouchthermophoneswerefabricatedwhichprovidealowfre-
quencyresonance.Additionally,aliquidfilledthermophonedemonstratesasmoothresponseoverawidefrequencyband.
10:25–10:40Break
M
10:40
A
2aEA5.Cylindricalheatconductionmodelsforenclosedthermophones.BenjaminDzikowicz,JamesTressler,andJefferyW.Bald- E.
win(NavalRes.Lab.,4555OverlookAve.SW,Washington,DC20375,[email protected]) U
T
Theefficiencyofenclosedthermophonesisgovernedbythetime-dependentheattransportbetweentheheatingelementandtheen- a
2
closuregas.Efficiencygainshavebeenmadebyreducingtheheatcapacitanceoftheheatingelementssothatamaximumamountof
energyisavailablefortransport.However,efficiencyisstilllimitedwhenthereispoorconductionintoandoutoftheenclosuregas.An
analyticalmodelfortheconductioninanenclosedthermophonewithaheatingelementcomposedofaregularlyspacedlineararrayof
conductingfiberswillbepresented.Themodelconsidersinteractionbetweentheindividualfibersandtreatstheenclosurewallasaheat
sink.Theconductionmodelwillbeincorporatedintoadevicemodelwhichcancalculatesteady-stateacousticoutput.Theresultsare
comparedagainstexperimentaldata.Inaddition,thedevicemodelcanbeusedtoexploretheoptimalfiberspacingforenclosedthermo-
phoneswithregularlyspacedlineararrayheatingelements.[WorkfundedbytheNavalResearchLaboratory.]
ContributedPapers
11:00 filmwithlowheatcapacityproducesatemperaturewaveaccompaniedby
anacousticwaveinafrequencyrangeof1Hzto100KHz. Theexisting
2aEA6.Carbonnanotubecoaxialthermophoneforautomotiveexhaust
lumpedparametermodelsfortheplanarCNTthermophonesarenotappro-
noise cancellation. Suraj M. Prabhu, Andrew R. Barnard (Mech. Eng.,
priateforthecomplexgeometriesoftheCNTfilm.UsingCOMSOLmulti-
Michigan Technolog. Univ., 1400 Townsend Dr., 815 R.L. Smith Bldg.,
physics, an electrical-thermal-acoustic model of the non-planar CNT
Houghton,MI49931,[email protected]),andMahsaAsgarisabet(Mech.
thermophonehasbeendeveloped.Byapplyinganalternatingelectricalcur-
Eng.,MichiganTechnolog.Univ.,Plymouth,MI)
rent to the CNT film, the temperature variation was obtainedand used to
Exhaustnoisefromautomobilesisamajorconcernandneedstobecon- simulatethepressuredistribution.Fordifferentinputpowerlevels,thetem-
trolled. Current noise control systems, mainly mufflers, have significant perature distribution on the CNT film was compared to the experimental
size,weight,andperformancelimitationsatlowfrequencies.Passivecon- datafromthermalcamera.Theexperimentalsoundpressurelevelatdiffer-
trolsystemsareunabletocancelnoiseefficientlyovertheentirefrequency entlocationsinfrontoftheCNTthermophonewererecordedandusedto
spectrum.Activenoisecontrolsystemhelpstoovercometheabovelimita- validatethenon-planarmodel.
tion.Thispaperdealswiththedesignandtestingofacoaxialcarbonnano-
11:30
tube speaker for active cancellation of automotive exhaust noise. Carbon
nanotubesarevirtuallymasslessandworkonthethermo-acousticprinciple. 2aEA8. Application of carbon nanotube thermophones in consumer
Theirabilitytosustainheatmakesthemsuitableforuseinelevatedtemper- electronics. Stephania M. Vaglica (Mech. Eng., Michigan Technolog.
atureenvironmentssuchasautomotiveexhausts.Analyticalcalculationsare Univ., 52134wemblyct, Shelbytwp, MI 48315,[email protected])and
performed using transfer matrix method to evaluate the effect of coaxial Andrew Barnard (Mech. Eng., Michigan Technolog. Univ., Houghton,
thermo-phoneandsidebranchspeakersonthesoundpressurelevelinthe MI)
exhausttailpipe.DesignofthecoaxialCNTthermophoneandtestingofit
bymountingonanautomotiveexhausttailpipearediscussed.Lowfrequen- Athermoacoustictransducerisadevicethatconvertselectricalenergy
cies (20 Hz–1000 Hz) are considered to evaluate the performance of the into heat energy which then generates sound energy. Carbon nanotubes
thermophone. For active cancellation of exhaust noise, Filtered-X Least (CNT) are a thermoacoustic transducer that have the ability to transform
MeanSquare(FXLMS)algorithmisdevelopedandimplementedusingNI this energy. Carbon nanotubes are hexagonal lattice tubes of carbon that
LabVIEW. have diameters one ten thousandth of the thickness of human hair. These
graphite allotropes of carbon have a range of different applications and
11:15 properties, particularly thermoacoustic conductivity. Because of their
unique thermoacoustic properties, a lightweight loudspeaker can be
2aEA7.An experimentally validated electrical-thermal-acoustic model
designedbycreatinganalignedfilmofcarbonnanotubes.CNTsformnano-
of non-planar carbon nanotube thermophones. Mahsa Asgarisabet,
scaletubesthatarepositionedina“forest”likeconfiguration.Unlikeatypi-
AndrewR.Barnard,andSurajM.Prabhu(MichiganTechnolog.Univ.,815
cal loudspeaker, there is no magnetic coil that generates sound. Instead,
R.L.SmithMEEMBldg.,1400TownsendDr.,Houghton,MI49931,mas-
soundisgeneratedbythenanotubesfastcoolingandheatingproperty.This
[email protected])
cooling and heating effect will expand and contract the air around the
Carbonnanotube(CNT)thin-filmthermophonesareasolidstate,trans- speaker which will result in the propagation of a sound wave. This new
parent,magnet-free,stretchable,andlightweighttransducersthatworkvia type of speaker creates a brand new market for speciality consumer
thethermoacousticeffect.TherapidchangeinthetemperatureoftheCNT electronics.
2539 J.Acoust.Soc.Am.,Vol.142,No.4,Pt.2,October2017 174thMeeting:AcousticalSocietyofAmerica 2539