Manitoba Materials Conference 2011 May 11, 2011 Engineering & Information Technology Complex Atrium TheManitobaMaterialsConferencepostercompetitionbringstogetherstudentsandpostdoctoralfellowsfrom36researchgroupsacrosstheuniversityfromthedepartmentsofChemistry,CivilEngineering,Electrical&ComputerEngineering,GeologicalSciences,Mechanical&ManufacturingEngineering,Physics&Astronomy,FoodScienceandTextileScience.ThiscompetitionissponsoredbytheManitobaInstituteforMaterials.ConferenceChair:Dr.JohanvanLierop,Physics&AstronomyMIMDirector:Dr.MichaelFreund,Chemistry ComplexCrystallineMaterialsandNanostructures[1] RAMANSPECTROSCOPYOFTHECARBONACEOUSMATERIALFROMTHEKAPOETAMETEORITE:EVIDENCEFORTHEEXISTENCEOFMICRO/NANODIAMONDSAbdu,Yassir,PostdoctoralFellowGeologicalSciencesAdvisor:Dr.F.C.Hawthorne Nanometer‐sized(1‐3nm)diamondsthatpre‐datetheformationofoursolarsystem(presolarnanodiamonds)werefirstdiscoveredinmeteorites[1].Theywerenamedpresolarorinterstellarnanodiamondsbecausetheycontainisotopicallyanomalousnoblegases,particularlyXe‐HL,whichisenrichedbothintheheavy(H)andthelight(L)isotopesofXe.Theoriginandtheprocessbywhichthesepresolarnanodiamondshaveformedisstilldebated,howevermanyauthorsfavortheformationfromaprocesssimilartothechemical‐vapor‐deposition(CVD),whichisusedinthelaboratoryfortheproductionofnanodiamonds.Ramanspectroscopyisapowerfultechniquethatiscommonlyusedintheanalysisofcarbon‐basedmaterials,andithasrecentlybeenappliedtostudydiamondsinmeteorites[2].Herewereportonpreliminaryresultsfrommicro‐RamanspectroscopymeasurementsonacarbonaceousmaterialfromtheKapoetameteorite.TheRamanspectraindicatethepresenceofmicro/nanodiamondscoexistingwithagraphite‐likeamorphouscarbonphase.TheresultswillbediscussedinrelationtoRamanstudiesofdiamondfromothertypesofmeteoritesandsyntheticCVDnanodiamonds.[1]Lewis,R.S.etal.1978,Nature,326,160.[2]Karczemska,A.etal.2007,DiamondandRelatedMaterials,16,781.[2] SUPPRESSIONOFBLOCKINGBEHAVIORINAMACROSCOPICFCCNANOPARTICLECRYSTAL Desautels,Ryan,Ph.D.CandidatePhysicsandAstronomyAdvisor:Dr.J.vanLierop

Anincreasedawarenessofourdependenceonnon‐renewableresourcesisdrivingtheneedformoreenergyefficienttechnologies.Newfunctionalmagneticmaterialsareessentialcomponentsforthedevelopmentofthesetechnologies.Nanoscalephysics,physicsatsizescomparabletoaDNAhelixoravirus,isarapidlygrowingareaofresearchwhichstrivestounderstandanddevelopthesenewmagneticmaterials.Itiswellknownthatsyntheticmaterials(metamaterials)exhibitinterestingmagneticproperties.Thesepropertiesaregenerallydifferentthanthoseoftheisolatedcomponentsorthebulkmaterial.Wepresentanovelproteincrystallizationtechniquewhichallowsustofabricatebulkthree‐dimensionalorderedarrays(nanocrystals)ofmagnetoferritinnanoparticles.Theseperfectlyfacetedcrystalsofmagnetoferritinnanoparticlesofsizesuptoafewhundredmicrometersmitigatetheeffectsofstructuraldisorderrevealinglongrangemagneticorderingeffects.Acomparisonofthemagneticpropertiesbetweenuncrystallizedamorphousmagnetoferritinnanoparticlesandthree‐dimensionalcrystalsofmagnetoferritinnanoparticlesrevealthedifferencescausedbyinterparticleinteractions.Forexample,interparticleinteractionsalterthetemperaturedependenceofthelowfieldmagnetizationandsusceptibility.Surprisingly,nosuperparamagnetismwasdetectedinthenanocrystalupto400K,significantlyaboveroomtemperature,whereastheuncrystallizedmagnetoferritinnanoparticlesexhibitsuperparamagnetismabove50K. [3] CHARACTERISINGLONE­PAIRACTIVITYOFBIREFRINGENTLEAD(II)COORDINATIONPOLYMERSBY207PBSOLID­STATENMRGreer,Brandon,M.Sc.CandidateChemistryAdvisor:Dr.S.KroekerLead(II)coordinationpolymerscomposedofmetal‐organicfragmentsareoftenvaluedinopticalapplicationsfortheirbirefringence,owingtothewiderangeofstructuralandelectronicattributesthatcanbeaccessedthroughpolymerdesignandtuning.Thestereochemicalactivityofthelone‐pairelectronsonthelead(II)atomhasadecisiveimpactonthelocalgeometry,andcorrespondingly,ontheextendedcrystallinestructure.Weusesolid‐state207PbNMRanddensityfunctionaltheorycalculationstoinvestigatetherelationshipbetweenlone‐pairactivityandstructureforaseriesoflead(II)coordinationpolymerscontaining[N(CN)2]‐or[Au(CN)2]‐bridgingligandsandsubstitutedterpyridineancillaryligands.207Pbanisotropicshieldingexhibitscorrelationswithlocalstructureandbirefringentproperties,whileDFTcalculationsdescribetheeffectofligandbasicityonlead(II)lone‐pairactivity.Thisworkprovidesacompellinglinkbetweenspectroscopicandopticalproperties,suggesting207PbNMRmayhavearoleinmaterialsdesign. [4] SPINWAVEEVOLUTIONINFERROMAGNETICMICROSTRUCTURESHayward,Lauren,UndergraduateStudentPhysicsandAstronomyAdvisor:Dr.B.SouthernConfinedspinwavesinsinglemagneticmicrostripsareinvestigatedusingamicrowavephotovoltagetechnique.Directmappingofthespinwaveevolutionbetweensurface,edge,

andcentralmodesisachievedbytuningthedirectionoftheappliedmagneticfield.Boththeoreticalandnumericalmethodsareusedtostudytheevolutionoftheexcitationsandprovideexcellentagreementwiththeexperimentalresults.Themostprominentfeatureobservedisamoderepulsingbehaviorwhichindicatesmodehybridizationinthedipoledominatedpartofthespinwavespectrum. [5] THEORETICALMODELFORELECTRONDENSITYWAVESHAVINGTHEGRAPHENESTRUCTUREHernandez‐Melgar,Javier,B.Sc.(Hons.)CandidatePhysicsandAstronomyAdvisors:Dr.J.M.VailandDr.Z.WangWehavedevelopedatheoreticalmodelfortheanalysisoftwodimensionalelectrondensitywavessuchthattheminimaoftheself‐consistentfield(SCF)single‐electronenergyhavethesamepatternastheatomicsitesingraphene.Themany‐electronsystemisdescribedverysimplyintermsoftightbindingwithatomic‐likebasisfunctionsfromtheHartreeapproximation.Weconsiderthecasewheretheperiodicpotentialduetotheatomiccoresofthehostmaterialissuppressedinfavorofaneffectiveelectronmass.Theonlyperiodicpotentialinthemodelsystemisthenduetotheelectrondensitywave.Inorderforelectrondensitywavestoconstitutethestablegroundstate,theeffectivepairwiseelectron‐electroninteractionmustincludenotonlyCoulomb,butothercontributions.Theseadditionalcontributionsarecommonlyattributedtoelectron‐phononinteraction.Iftheeffectivepairwiseinteractionleadstoastablegroundstatewithperiodicelectrondensityhavingthegraphenestructure,thensuchsystemsmaybeinvestigatedintermsofelectron‐phononcouplingstrength.Variationofchemicalcompositionandotherstaticcharacteristics,areoftenconsideredwhenattemptingtowidentherangeofsystemspossessingsomeoralloftheelectronicpropertiesofgraphene.Thepresentworkthenaddsdynamichost‐systemcharacteristicstostaticconsiderationsforsuchstudies.Inthepresentwork,thesolutionoftheHartreeequationdependsonsatisfyingthemathematicalself‐consistencyconditionbetweentheparametersoftheatomic‐likebasisfunctionsandtheeffectivepairwisecoupling.ForsystemsthatcansatisfytheSCFcondition,thequestionofstabilitymustbeaddressed:Isthereamany‐electronconfigurationhavinglowerenergythanthedensitywave?ItcaneasilybeseenthatauniformelectronicdensityisasolutionoftheHartreeequationswhentheeffectivemassapproximationisused.Thusthedensitywavestatewillonlybestableifitstotalenergyislessthanthatoftheuniformdensitystate.WehavedeterminedtheanalyticalformoftheSCFcondition,usingcylindricallysymmetricharmonicoscillatorwavefunctionsfortheatomic‐likebasis.FurtherworkinprogressaddressestheSCFandtotal‐energystabilityconditions,tobeanalysedquantitatively. [6] UNDERSTANDINGANDCONTROLLINGTOPOTACTICREDUCTIONSOFN=1RUDDLESDEN­POPPERMANGANATESHernden,Brad,M.Sc.CandidateChemistryAdvisor:Dr.M.Bieringer

Overthelastdecademetalhydridesolidstatereductionshaveledtothesynthesisofmanynoveloxygendefecttransitionmetaloxides.Thistechniqueprovidesinsightintosolidstatereactionmechanismswhichareunderkineticcontrol.Progresstowardsstep‐wisemechanisticreactionsinsolidstatechemistryisbecomingviableusingthistechnique.Limitationsincurrentliteratureincludetheabsenceofwellcharacterizedmetalhydridereactivityasreductantsandrationalizationforthechoiceofmetalhydridereductantused.

LowtemperaturemetalhydridereductionsoftheSr2‐xCaxMnO4(0<x<2)systemhasbeenexplored.UsingavarietyofgroupIandIImetalhydridesassolidstatereductantsallowedforevaluationofreactiontrendsforthereductionofmanganateRuddlesden‐Popperphases.ThesetrendsemphasizethedifferencesinreactivityamonggroupIandIImetalhydridesandtheimpactofmetalhydridechoiceonthetopotacticreduction.ThetargetedsynthesisofSr2MnO4‐x(0<x<0.37)phaseswillbepresentedincludingtheuseofnovelhydridereductants.

InadditionthepotentialinsertionofsmallcationsintotheRuddlesden‐Popperphasesduringsolidstatereductionwillbepresented. [7] INVESTIGATIONOFTWOSTEPFORMATIONPATHWAYOFAPOTENTIALSOLIDOXIDEIONELECTROLYTEIN­DOPEDCeO2 Shafi,Shahid,Ph.D.CandidateChemistryAdvisor:Dr.M.BieringerCommercialoxide‐ionelectrolyteshavethefluoritestructurewithanionvacancies.CeO2crystallizesinthefluoritetypestructure,dopingwithdivalentandtrivalentcationscreatesoxideionvacanciesinthestructuremakingthempotentialcandidatesforsolidoxide‐ionelectrolytes.InparticularlanthanumdopedCeO2(Ce(1‐x)LnxO2‐d)havedrawnsignificantattentionduetoveryhighoxideionconductivitycomparedtothatofY2O3‐dopedZrO2(YSZ).TheobjectiveofthisworkistoexploretheformationofIn‐dopedCeO2viaatwo‐stepsynthesisusingin‐situpowderX‐raydiffraction.In‐depthanalysisofreactionpathwaysviain‐situtechniquesisimportantasitallowsidentificationofmetastablephases.Often,ex‐situinvestigationwouldnotprovideasmuchinformationandnoteworthyintermediateswouldstayunnoticed.Theex‐situattemptsforthedirectsynthesisofIn‐dopedCeO2fromstoichiometricamountsofCeO2andIn2O3hasnotbeensuccessfuldespitesimilarionicradiiforIn3+andCe4+,thisreactionwasfollowedin‐situandconfirmedthatthedirectsynthesisisnotpossible.Thealternatetwo‐stepsynthesisrouteinvolvesformationofIn‐dopedperovskiteBaCe(1‐x)InxO3‐dandsubsequentdecompositionusingCO2.TheentirephasediagramofBaCO3‐CeO2‐In2O3andCeO2‐In2O3systemsbelongingtothissynthesiswillbepresented.TheCe(1‐x)InxO2‐dphasesaremetastableandcanonlybepreparedatlowtemperaturesthroughCO2capturereaction.ThecompetitionbetweenCO2capturereactionandIn‐dopedCeO2decompositionwasinvestigatedandthemaximumIn‐dopingthatcanbeachievedwithBaCe(1‐x)InxO3‐dasanintermediatewasidentified.TheCO2capturereactionisanexcellentrouteforthesynthesisofdopedCeO2andtheresearchmethodologiesdevelopedinthisstudycanbeextendedtootherpromisingmaterials. [8] SURFACESPINSTABILITYINγ­Fe2O3NANOPARTICLESWITHACuSHELLSkoropata,Elizabeth,M.Sc.Candidate

PhysicsandAstronomyAdvisor:Dr.J.vanLieropThesmallsizeandhighsurfaceareaofnanoparticlesmakethemattractivecandidatesforuseinawidevarietyofapplicationssuchasdrugdelivery,datastorageandcontrastenhancementformagneticresonanceimaging.However,thesuitabilityofnanoparticlesforuseinsuchapplicationsreliesonhowwelltheirresponsetoanexternallyappliedmagneticfieldcanbeunderstoodandcontrolled.Finitesizeandsurfaceeffectstendtosuppressthemagneticresponseofnanoparticle,andacurrentchallengefacingmaterialsresearchersistooptimizethemagneticpropertiesofnanoparticlesandcreatenanoparticleswithmagneticpropertieswellsuitedtoapplications.Inordertostudytheeffectthatthesurfaceenvironmentofananoparticlehasonthemagneticpropertieswehavesynthesizedbareγ‐Fe2O3andnovelγ‐Fe2O3core/Cushellnanoparticlesandexaminedthechangesinthemagneticpropertiesbetweenthetwosystems.Thestructureandcompositionofeachsamplewascharacterizedusingtransmissionelectronmicroscopy,x‐raypowderdiffractionandx‐rayphotoelectronspectroscopy.ResultsindicatedthatforallCushellthicknessesamonolayerofCuOhadformedatthecore/shellinterface.WhilebulkCuOhasnonetmagnetization,x‐raymagneticcirculardichroismresultsindicatedthattheinterfacialCuOlayerwasmagnetized.ThemagneticCuOinteractedwithFeionsatthesurfaceoftheγ‐Fe2O3nanoparticleswhichresultedinanincreaseofthemagnetizationofthenanoparticlethatindicatedarecoveryoftheγ‐Fe2O3surfacemagnetism. [9] NONLINEARMICROMAGNETICSIMULATIONSOFPERMALLOYSTRIPSWismayer,Matthew,PostdoctoralFellowPhysicsandAstronomyAdvisor:Dr.B.SouthernConfinednonlinearspin‐wavemodesinapermalloy(Py)rectangularstripareinvestigatedusingthemicromagneticmethodtosolvetheLandau‐Lifshitz‐Gilbertequationfordampedprecessionalmotion.Thestudyinvolvesaccuratelymodelingtherelaxedanddynamicstatesforanormallymagnetisedmicrostrip.Therelaxedstateisdeterminedbyapplyingalargestaticmagneticfieldperpendiculartothestripplanetherebysaturatingthetotalmagnetisation.Thedynamicstateismodeledbyapplyingatimedependentsinusoidalfieldofconstantamplitudeandfrequencyalongthelengthofthestrip.AFourieranalysisofthedynamicmagnetisationisusedtomapoutthespin‐wavemodespectrumasafunctionoftheappliedstaticfield.Thespin‐wavespectruminthenonlinearregimeshowsgoodqualitativeagreementwithmeasurementsobtainedfromthephoto‐voltagetechnique.Thesemicromagneticsimulationsexpandthecurrentunderstandingonhownonlinearspin‐wavemodesinteractviathemagnetostaticforce. [10] AGENERAL,ONE­POT,GREENMETHODFORTHESYNTHESISANDFUNCTIONALIZATIONOFMETALOXIDENANOPARTICLESWorden,Matthew,M.Sc.CandidateChemistryAdvisor:Dr.T.Hegmann

Theriseofnanotechnologyalongwithincreasinginterestindevelopingsimpler,environmentallyfriendlysyntheticmethodspointstoaneedtoapplyto‘green’techniquestonanofabrication.Thiswasaccomplishedasshowninarecentpublicationfromourgroup,whichdetailedaone‐pot,aqueous,roomtemperaturesynthesisofmagnetite(Fe3O4)nanoparticlesthroughthereductionofanorganometallicprecursorwithsodiumborohydride.Researchfocusingonoureffortstoexpandthisproceduretoamoregeneralsynthesisofawidevarietyofmetaloxidenanoparticles(e.g.,Mn3O4,Co3O4,aswellasmixedmetaloxides)willbepresented.Analyticaldata‐suchasXRD,XPS,andIRspectroscopy‐characterizingtheparticleswillbeincluded.Furthermore,thisprocedureallowsforavarietyofhydrophilicandhydrophobiccoatingstobeappliedontotheparticles,anecessarysteptowardsspecificapplications.Ourongoinginvestigationsintothetechniquesinvolvedinobtainingcertaincoatingsandtheeffectsthereofwillalsobepresented. [11] CHARACTERIZATIONANDBIO­COMPATIBILITYOFIRONOXIDENANOPARTICLESSYNTHESIZEDUSINGANOVELONESTEP,LOWTEMPERATUREREDUCTIONMETHODYathindranath,Vinith,Ph.D.CandidateChemistryAdvisor:Dr.T.HegmannIronoxidenanoparticles(IONPs)haveanumberofemergingapplicationsinclinicalmedicineandhencethereisagreaterdemandforbetterwaysofpreparingIONPsthatarebiocompatible.Herewereportaversatileone‐potroomtemperaturesynthesisofIONPsfromiron(III)acetylacetonatefollowinganewhydrolysis/reductionmethod.Usingthismethod,wehavemade‘bare’,hydrophilicpoly(ethyleneglycol),L‐arginineandL‐glutamicandhydrophobicoleicacidcoatedIONPs.PhysicochemicalcharacterizationoftheresultingIONPswereperformedusingpowderx‐raydiffraction,transmissionelectronmicroscopy(TEM),FouriertransforminfraredspectroscopyandMossbauerspectroscopy.TheaverageparticlesizedeterminedusingTEMfortheIONPssynthesizedatroomtemperaturewerearound5nmwithnarrowsizedistribution.Todeterminebio‐compatibilityoftheIONPs,cellviabilityassayswereperformedinCaco2andHepG2celllinesusingMTTcytotoxicityassay.PermeabilityofhydrophobicoleicacidcoatedIONPswerecarriedoutonconfluentmonolayersofhumanbrainmicroendothelialcellsgrownonTranswellmembraneinserts.Inthepermeabilitystudies,IONPswerefoundinallcasesinthereceivercompartmentafter24hoursasdeterminedbythePrussianblueabsorbancewithrespecttothecontrol(whichdidn'treceiveanyIONPs).OleicacidcoatedIONPsexhibitedpoordispersibilityinDMEM,butstillpermeatedthecellmembraneinallcases.AppliedmagneticfieldclearlyproducedanenhancementinthepermeabilityofIONPsover24hours. ComplexNaturalSystems [12] DETECTINGTHEELECTRO­DEFORMATIONOFBIOLOGICALCELLSINMICROFLUIDICCHANNELS­AMECHANISMFORBIOPHYSICALFLOWCYTOMETRY

Ferrier,Graham,Ph.D.CandidateElectricalandComputerEngineeringAdvisor:Dr.D.ThomsonTheelectricalpropertiesofabiologicalcellarelinkedtoitssurfacemorphologyandmechanicalproperties,whichprovideinsightintoitsphysiologicalstate.Inthiswork,biologicalcellsflowinginafluid‐filledchannelgenerateposition‐dependentelectricalsignatureswhilepassingoverapairofinterdigitatedcoplanarelectrodes.Low‐(<3MHz)andhigh‐frequency(1.5GHz)electricalsignalsarecoupledtotheelectrodestoactuateanddetectcells,respectively.Inconductivecellbufferssuchasphosphatebufferedsaline(PBS),thelow‐frequencysignalforcescellsawayfromtheelectrodestowardthetopsurface(ceiling)ofthechannel.Atsufficientlylargesignalstrengths,thesecellsarepressedintotheceiling,andmaysubsequentlybecomedeformed.High‐frequencysignalsprovidethesensitivityrequiredtodynamicallydetectthecell‐to‐wallinteraction.Distinctelectricalsignaturesareobservedwhencellsaredrivenintocontactwiththeceiling,ascomparedwiththeequivalentsignaturesfrom"rigid"polystyrenespheres.Simulationsoftheequationofmotionareusedtoestimatetheexperimentaltrajectoriesofbothun‐actuatedandactuatedcellsastheypassovertheelectrodes.Sincedistinctivecellphenotypesexhibituniquesurfaceandmechanicalproperties,theirrespectivewallinteractionsmayformabasisfortheirdifferentiation. [13] FINGERPRINTINGTURQUOISEDEPOSITSINTHEAMERICANSOUTHWESTHull,Sharon,Ph.D.CandidateGeologicalSciences/AnthropologyAdvisor:Dr.M.FayekArchaeologistshaveusedanumberofgeochemicaltechniquestoobtainprovenanceinformationtodevelopandrefinemodelsforhumanmigration,localexchangenetworks,andlarge‐scaletradestructures.Techniqueshavebeendevelopedtoanalyzeavarietyofarchaeologicalmaterialsuchasobsidian,turquoise,quartz,marble,chert,andceramics.Newinstrumentationislessdestructive,moreprecise,andrequireslessmaterialforanalysis.Regardlessofinstrumentationandnewtechniques,tobeginreconstructionormodelthetransportofmineralresourcesitisnecessarytohaveaccurateknowledgeofthemineralofinterestandtheprovenanceregions.Forexample,wedevelopedatechniquetogeochemicallyfingerprintturquoiseprovenanceregionsusingtheisotopiccompositionsofhydrogen(D/H)andcopper(65Cu/63Cu)measuredbyanionmicroprobe.Theuseofisotopicratiosovercomesmanyofthelimitationsexperiencedinearlierstudiesusingtraceelementcompositionpatterns.Turquoiseisacomplexmineralandtheuseofamicroanalyticaltechniqueforanalyzingsolidsamplesallowsustoavoidinclusionsandmatrixthatmaybepresentinsamplespreparedforbulkanalysesandtheartifactscanbereturnedtotheiroriginalcollections.Asturquoiseartifactsaregeochemicallycharacterized,theirsignaturesareaddedandcomparedtoadatabasethatalsocontainsthegeochemicalfingerprintsofturquoiseprovenanceregions.Thisdatabaseisanon‐goingprojectthatwillcontinuallyexpandasmoreturquoiseprovenanceregionsandartifactsareanalyzedallowingexaminationofturquoiseprocurementstrategiesandexchangethroughtimeandspace.

[14] CHARACTERISTICSOFFEMTOSECONDLASERABLATIONONBIOMINERALSYang,Panseok,M.Sc.CandidateGeologicalSciencesSuppressedparticle‐size‐related‐fractionation(PSRF)andimprovedparticlesizedistribution,makesfemtosecond(fs)laserablationthepreferredsolidsamplingmethodovernanosecond(ns)laserablation,especiallyforvolatileelementsandelementswithhighfirstionizationpotentials.Inthisstudy,volatileelementssuchasZn,Hg,andPbinbiominerals(fishotolithsandfin‐rays)wereanalyzedbyTi:sapphirefs(~46fs)near‐infrared(=785nm)laserablationinductivelycoupledplasmamassspectrometry(NIR‐fs‐LA‐ICP‐MS)andwerecomparedwiththeresultsofNd:YAGns(~6ns)ultra‐violet(=213nm)laserablation.Inadditiontothevolatileelements,Sr,Ba,Cu,andCdwerealsoanalyzedforcomparisonbetweenthetwolaserablationtechniques.ConcentrationsoftheelementsweredeterminedbyusingMACS‐3,apelletedcalciumcarbonatereferencematerialobtainedfromUSGeologicalSurvey.Thesignalof43Ca+wasusedasaninternalreference,correctingforvariationsinthelaserablationyieldandtransportefficienciesandsensitivityoftheinstrument.ForNIR‐fs‐LA‐ICP‐MS,theinfluenceofvariouslaserparameters‐beamdiameters,focuspositionsrelativetosamplesurface,repetitionrates,laserfluences,andscanspeed‐ontheablationofbiomineralsisevaluated.Femtosecondlaserablationprovidedimprovedaccuracy,superiortothatobtainedusingnsLA‐ICP‐MS.Furthermore,fslaserpulsessignificantlyreducethefrequencyandamplitudeofspikesinsamplesignalscommonlyobservedfromnslaserablation,andthusreducefractionationatthelaserbeamsites.Thesereducednoiselevelsfromfslaserablationcancontributetomorepreciseisotoperatiodetermination.[15] WIRELESSHYGROTHERMALTRANSDUCERFORBUILDINGSTRUCTUREHEALTHMONITORINGZhao,JunHui,PostdoctoralFellowElectricalandComputerEngineering/ISISCanadaAdvisor:Dr.D.ThomsonHygrothermalbehaviorhasagreatimpactonthestrengthandintegrityofthebuildingcomponents.Formonitoringmoistureinducedstructuraldeteriorationandperformancedegradationsuchasfrostdamageandmoldgrowth,awireless,passiveinductor‐capacitor(LC)resonantcircuittechniqueisexploredformeasurementofthemoisturelevel.TheworkingmechanismisbasedoncapacitancechangeinducedbyvariationofeffectivedielectricconstantduetothepresenceofwaterwithinthebuildingmaterialssuchasstonesandthecorrespondingchangeoftheresonantfrequencyoftheLCcircuit.Themoisturelevelcanbedeterminedbydetectingtheresonantfrequencyshift.Inthisstudy,theLCresonantcircuitmoisturesensorconsistsofaninductivesensingcoilandacapacitorformedbytwostainlesssteelbars.Anotherinductiveinterrogatorcoilwasbuiltasasignaltransmitterandreceiver.ThecouplingsignalbetweenthesensingcoilandinterrogatorcoilwasmeasuredusingImpedanceAnalyzer.Arelativehumidity(RH)sensorwasimbeddedinsidetheholebesidethetwobarssothatthemoisturelevelinsidethestonecanalsobeevaluatedbasedontheRHvalue.Withthewatermoisturecontinuallypenetratingintotheregionbetweentheelectrodesofthetwobars,accumulationofthemoistureincreasesthe

effectivedielectricconstant,leadingtotheincreaseofthecapacitanceandthecorrespondingshiftoftheresonantfrequency.Theresonantfrequencychangedfrom5.96MHzto4.80MHzwhilethemoisturesensorindicatedtherelativehumidityinsidethestonechangedfromabout10%to100%atroomtemperature.Theresultsfordryingcycleswerealsoinvestigated.Sinceelectricalsignalcanbeinductivelytransmittedbetweentwospiralinductorswhichcanbeseparatelypositionedinthedifferentlocations,thus,wirelessmonitoringofthestructuralhealthbecomespossibleusingasimplyconfiguredtwobarscapacitivecomponentandaninductioncoil.Inaddition,thesesensorscanworkwirelesslywithoutrequiringbatteries. CompositeMaterialSystems [16] DEVELOPMENTOFCOMPOSITEMETEOROLOGICALTOWERSAlshurafa,Sami,Ph.D.CandidateCivilEngineeringAdvisor:Dr.D.Polyzois AnewgenerationoftowersisbeingdevelopedattheUniversityofManitobatosupportmeteorologicalandwindmonitoringinstrumentsthataddressissuesoficing,durabilityandsurvivabilityincoldclimatesusingcompositematerials.Theresearchprojectinvolves:analysis,designandfabricationoffullscalecompositetowers;testing;monitoringthestructuralandserviceabilityperformanceundersevereweatherconditions;and,icingmitigationtoensurethecontinuousoperationofthetowers. [17] MODELFORTIME-DEPENDENTDAMAGEEVOLUTIONANDITSINFLUENCEONCREEPOFMULTIDIRECTIONALPOLYMERCOMPOSITELAMINATES Asadi,Amir,Ph.D.CandidateMechanicalandManufacturingEngineeringAdvisor:Dr.R.JayaramanVariousdamagemodesthatevolvewithtimeinpolymercompositelaminates,suchastransversecracking,verticalcracking,delamination,andfiberfracture,aswellastheinteractionamongthem,influencethetime‐dependentdegradationinmodulus(creep)andstrength(creeprupture)ofpolymercompositelaminates.Thisstudyisfocusedonmodelingsimultaneoustime‐dependentevolutionoftransversecrackinginmultiplepliesofamultidirectionalpolymercompositelaminate(e.g.[θm/90n]s,[0/θm/90n]s),theirinfluenceoneachother'sevolutionandtheireffectoncreepofpolymercompositelaminates.Thedevelopedmodelisbasedonvariationalanalysisandmodifiedlaminationtheory.Thevariationalanalysismoduleinthemodelisusedtodeterminethestressstateatanygivencreeptime.Then,thestoredelasticenergy,determinedusingthisstressstate,iscomparedwithacriticalenergyforfracturetodeterminethecrackevolutionwithcreeptime.Thecreepstrainiscalculatedusingthemodifiedlaminationtheorymoduleofthemodel.Modelpredictionsarecomparedwithexperimentalresultstovalidatethemodel. [18] BIO-COMPOSITESFROMHEMPFIBERS

Fahimian,Mahi,Ph.D.Candidate&O'Connor,Brian,UndergraduateStudentMechanicalandManufacturingEngineeringAdvisor:Dr.R.JayaramanNaturalfiberbio‐composite,consistingofunsaturatedpolyesterandneedle‐punchednon‐wovenhempfibermats,hasbeendevelopedtoreplaceglassfibercompositesintransportationapplications.Thecompositeshavebeenmanufacturedusingvacuumassistedresintransfermolding(VARTM)andhempfibermats.Thepropertiesofthecompositehavebeentailoredbycontrollingthematmanufacturingparameterssuchaspunchdensityandpunchdepth.Biocompositeswith20%fibervolumefractionshowamodulussimilartothatofglassfibercompositewith30%fibervolumefraction.Variousfibersurfacetreatmentshavebeenstudiedtoimprovethehempfiber‐matrixinterfacialbonding.Acrylonitriletreatedfibershavebeenfoundtoprovideoptimalbondingandcompositeproperties.Demonstrativebuspartshavebeenmanufacturedusingthishempfiberbiocomposite. [19] POLYMERNANO­COMPOSITE Khorsand,Amirreza,Ph.D.CandidateMechanicalandManufacturingEngineeringAdvisor:Dr.R.JayaramanPolymercompositesareimportantcommercialmaterialswithapplicationsthatincludefilledelastomersfordamping,electricalinsulators,thermalconductors,andhigh‐performancecompositesforuseinaircraft.Duringthepastfourdecades,thepropertiesofpolymercompositeshavebeentailoredattwo‐threesizescales,millimeter(laminatelevel),micrometer(laminalevel),andsub‐micron(fibrelevel).Discoveryofcarbonnano‐tubes(withdiametersintherange10‐50nm(1nm=10‐9m),lengthoffewmicrons,modulusandstrength1000timesand100timesthatofthecurrentlyusedcarbonfibers,hasignitedthecurrentinterestintailoringthestructureofcompositesinafourthsizescale,namelythenano‐scale.Currentefforts,intherealmofstructuralcomposites,areexclusivelyfocusedonnanocarbonfibers/tubesandnano‐clay.Dependingonthereinforcement,bothstructuralandfunctionalpropertiescanbetailoredintoacomposite.Forexample,usingcarbonnano‐tubes,bothmechanicalandelectricalpropertiescanbeimprovedsignificantly.Currentresearchisfocusedontailoringthecompositepropertiesbycontrollingthestructureatallfoursizescales.Asafirststep,structureatthenano‐scaleisfocused.Compositemicrofiberswithnanoreinforcementaremanufacturedbymeltspinninganditspropertiesarecharacterizedasafunctionofreinforcementgeometry,orientation,andvolumefraction. [20] NOVELCONDUCTINGPOLYMER­HETEROPOLYACIDHYBRIDMATERIALFORARTIFICIALPHOTOSYNTHETICMEMBRANESMcDonald,Michael,Ph.D.CandidateChemistryAdvisor:Dr.M.FreundArtificialphotosynthetic(AP)approachestoconvertandstoresolarenergywillrequire

membranescapableofconductingbothionsandelectronswhileremainingrelativelytransparentandchemicallystable.Anewapproachisappliedhereininvolvingpreviouslydescribedinsituchemicalpolymerizationofelectronicallyconductingpoly(3,4‐ethylenedioxythiophene)(PEDOT)inthepresenceofprotonconductingheteropolyacid(HPA)phosphomolybdicacid(PMA).TheelectrochemicalbehaviourofthePEDOT/PMAhybridmaterialwasinvestigatedanditwasfoundthattheconductingpolymer(CP)issusceptibletoirreversibleoxidativeprocessesatpotentialswherewaterisoxidized.ThiswillbeproblematicinAPdevicesshouldtheprocessoccurinverycloseproximitytoaconductingpolymer‐basedmembrane.ItwasfoundthatPEDOTgrantsthesystemgoodelectricalperformanceintermsofconductivityandstabilityoveralargepHwindow;however,thepresenceofPMAwasnotfoundtoprovidesufficientprotonconductivity.Thiswasaddressedinanadditionalstudybytuningtheionic(andinturn,electronic)conductivityincreatingcompositeswiththeproton‐permselectivepolymerNafion.Itwasfoundthatamaterialofthisnaturewithnear‐equalconductivityforoptimalchemicalconversionefficiencywillconsistofroughlythreepartsNafionandonepartPEDOT/PMA.[21] ELECTRICALCHARACTERIZATIONOFSEMICONDUCTINGMICROWIRESANDTHEIRJUNCTIONWITHIONICANDELECTRONICCONDUCTINGPOLYMERCOMPOSITESMcEleney,Kevin,PostdoctoralFellowChemistryAdvisor:Dr.M.FreundTheever‐growingdemandforenergyandthepressuretoreducerelianceonthefossilfuel‐basedeconomieshasencouragedconsiderablemotivationtodevelopcleanandrenewableenergysources.Solarenergyisperhapsthemostabundantenergysourcewehaveavailablethusapotentresource.Asthesolarfluxisnotconstantatalltimesofthedayweneedtodevelopawaytoharvestthelightenergyandstoreforlateruse.Utilizinglighttodriveredoxreactionswecanstoresolarenergyaschemicalbonds.Inordertoachievethisaworkingdevicewouldrequirealightharvestingcomponent(semiconductingmicrowires),redoxcatalystsandsomemethodforseparatingtheoxidationandreductionreactions(membrane).Aspartofaglobalefforttodevelopnewsolarenergycollectorswehavebeenexploringtheroleofthemembraneinmanagingionicandelectronicconductivityinthesystemaswellasthejunctionbetweenthesemiconductingmicrowiresandthemembrane.Thisworkwillfocusonthedevelopmentofnewcontactformingmethodsforsemiconductingmicrowiresaswellasthecharacterizationofthemicrowire‐conductingmembranejunction.[22] DESIGNANDFABRICATIONOFELECTRONIC/IONICCONDUCTINGMEMBRANESFORARTIFICIALPHOTOSYNTHESISMcFarlane,Shaune,PostdoctoralFellowChemistryAdvisor:Dr.M.FreundArtificialphotosyntheticsystemswillrequiremultifunctionalmembranes.Incontrasttofuelcells,suchasystemwillrequirethemembranetoconductbothionsassociatedwith

redoxprocessesandelectrons/holesassociatedwithlightabsorption.Anapproachtodesigningandfabricatinganartificialphotosyntheticmembrane,involvingacompositematerialfashionedfromstate‐of‐the‐artelectronicallyandionicallyconductingpolymerswillbepresented.Itwillbeshownthatwhileartificialphotosyntheticsystemsthatusethesepolymersasamembranematerialhaveattractiveelectronic,ionic,physical,andopticalproperties,thereareimportanttradeoffs,whichinturnpresentopportunitiesforthedesignandsynthesisofnewmaterialsforartificialphotosyntheticsystems. [23] STIFFNESSOFEXTRACELLULARMATRIXCONTROLCELLFATE­3DBIOMIMETICNANO-COMPOSITESCAFFOLDFORBONEREGENERATION Mohamed,Azeden,PostdoctoralFellowMechanicalandManufacturingEngineering/BiochemistryandMolecularGeneticsAdvisor:Dr.M.XingIntroduction:Recentdiscoveriesinnovelbiodegradablematerials,nanotechnologyandstemcellresearchhaveledtissueengineeredbonegrafttobecomeapromisingalternativetherapytorepairandre‐constructbonedefectscausedbytrauma,tumorsandcongenitaldiseases.Typicalbonetissueengineeringstrategiesutilizebiocompatibleandbiodegradablesyntheticscaffoldswithinwhichprogenitorcellsreside.Uponimplantation,thescaffoldprovidesastructuralsupportaswellasamicroenvironment(niche)toregulateprogenitorstemcelldifferentiationandpromoteboneregenerationbyutilizinglocalizedphysicalandbiochemicalcues.Oneofthesephysicalcues,elasticityoftheextracellularmatrix(ECM),hasbeenclearlydemonstratedtoinfluencethefateofcelldifferentiation.IthasalsobeenfoundthatsolelychangingthestiffnessoftheECMdictatesthecommitmentofmesenchymalstemcells(MSCs)tovariouslineagessuchasneurons,myoblastsandosteoblasts.However,themechanismofhowthephysicalcuesofECMstiffnessissensedandprocessedbyprogenitorcellstoregulatedifferentiationiselusive.Methods:ToinvestigatehowelasticityoftheECMregulatesprogenitorcellfates,wedesignedthree‐dimensional(3D)scaffoldswithcontrollablestiffnesscreatedbyvariouspercentagesofhydroxyapatite(HA)andcollagen(Col)composition,whicharethemajornaturalcomponentsofbone.Pre‐osteoblastswereseededintoscaffolds.TheimpactonosteogenesisinducedbyvariousstiffnessesoftheECMhasbeenverifiedbyimmunohistology,geneexpressionandproteinanalyses.BioinformaticswasemployedtoaidintheidentificationofthesignalingpathwayofmechanotansductionbetweenECMandcells.Results:Ithasbeenconfirmedthatmatrixstiffnessinfluencesosteogenesisinthebiomimeticscaffoldsbasedonthedatafromreversetranscriptionreal‐timePCR(RTqPCR). [24] XPSCHARACTERIZATIONOFPROTONANDELECTRONCONDUCTINGCOMPOSITESTan,Damaris,M.Sc.CandidateChemistryAdvisor:Dr.M.Freund

Membranecompositesconsistingofelectronandprotonconductingcompositeswillberequiredforartificialphotosyntheticapplications.Inordertofunctioninanartificialphotosyntheticdevice,theyneedtobeconductive,homogeneousandtransparent.Previousstudieshaveshownthat12%PEDOT‐PSSinNafionhassufficientelectricalconductivitytohandletheexpectedchargegeneratedinanartificialphotosyntheticdevice.However,atthisconcentrationofconductingpolymerthetransparencyofthismembraneisquitelow.Wecanimprovethetransparencybybleachingthemembrane.Thetwoconductingpolymersinaqueousdispersionweredropcasttoformafreestandingmembrane.Tobleachthemembrane,itwassoakedinhydrogenperoxideandirradiatedwithUVlight.ThesurfaceofthemembraneswerecharacterizedbyX‐rayphotoelectronspectroscopy(XPS).Thebleachedandaspreparedcompositeswerecomparedfortheirhomogeneityanddifferencesinthechemicalcomposition. HighPerformanceComputing [25] BENCHMARKINGOFDENSITYFUNCTIONALTHEORYMETHODSFORTHEOLEFINPOLYMERIZATIONCATALYSIS:ASEARCHFORRELIABLEREFERENCEMETHODSShamov,GrigoryA.,PostdoctoralFellowChemistryAdvisor:Dr.G.SchreckenbachRationaldesignoftheolefinpolymerizationcatalystsrequiresrealistic,thatis,largeenough,modelssystems,andacomputationalmethodabletoprovidebalanceddescriptionofallaspectsofthesesystems(activationbarriers,non‐bondedinteractions,etc.)ThecommonlyusedDFTmethodswereshowntohaveproblemswithsomeoralloftheseaspects,andnouniversalDFTrecipehasbeencreatedtodate.ThusthereistheneedofbenchmarkingofDFTmethodsinordertoachieveaccuratepredictions.However,fortransitionmetalcatalysis,experimentalkineticandthermodynamicdataarescarce.Standardhigh‐levelcoupledclustertheorymethodssuchasCCSD(T)cannotyetbeappliedtothelargersystemsduetotheirveryunfavorablescalingandhighbasissetrequirements.InthisworkwehavetestedthetwofollowingalternativestoCCSD(T):thesemiempiricalvariantsofspin‐scaledMP2theory(SCS‐MP2),andtheDiffusionMonteCarlo(DMC)method.WecompareresultsofthesemethodsagainstCCSD(T)forthesmallestTi(IV)modelcatalystofolefinpolymerization,consideringchaintransferandchainpropagationstepsthatdeterminethepolymermolecularweight.Then,forthelarger,morerealisticmodelswebenchmarkavarietyofpureGGA,globalandrange‐separatedhybrids,withandwithoutdispersioncorrections,againstSCS‐MP2andDMC.ThisworkispartoftheResearchProgrammeoftheDutchPolymerInstitute(DPI),Eindhoven,TheNetherlands,Project#641[26] ACCELARATINGOPTICALFLOWWITHHIGHPERFORMANCECOMPUTINGSharma,Bhanu;MijaresChan,JoseJuan,Ph.D.CandidateElectricalandComputerEngineering

Advisors:Dr.R.ThulasiramanandDr.G.ThomasThisworkaddressesafundamentalproblemfromimageprocessing,thecomputationofopticalflowanditscomputationalconstraints.TheOpticalflow,beingformfromasequenceofimages,isusedtodescribethemotionapproximationsofanobjectwithinanimageplane.Multiplemethodshadbeendevelopedsince1940s.Withinthiswork,thecorrelation‐basedcomparisonmethodisselectedduetoitsbetterperformanceagainstthelackofframesorapoorsignal‐to‐noiseratio.Eventhough,thecorrelation‐basedmethodisrobust,thecomputationalcostbecomesaconstraintforitsimplementation.Forthismatter,ahighperformancecomputingsolutionispresentedincludingtheuseofgraphicprocessingunitsanditsalgorithmicoptimization. HighTemperatureAerospaceMaterials [27] FAILUREMECHANISMOFREPAIREDPOLYCRYSTALINEIN738ANDDSR80SUPERALLOYS.Abrokwah,Emmanuel,M.Sc.CandidateMechanicalandManufacturingEngineeringAdvisor:Dr.N.L.Richards SuperalloyshavebeenusedquiteextensivelyinthepastdecadesinhightemperatureapplicationsintheAerospaceandPowergenerationindustriesduetotheirhighresistancetothecreep,fatigueandoxidationdamagingmechanism.Itsstrengthismainlyderivedfromprecipitatinggammaprimephaseandsolidsolutionalloying.ThecostoftheseSuperalloysareveryexpensivemakingrepairoptionstodamagedcomponentpartsmoreattractiveasopposedtobuyingnewequipmentwhentheyaredamaged.ReplacementcostforamodernHTPstage1bladeis$500,000USDperengine.Repaircostofupto60%replacementcostisfeasiblemakingthedrivetowardsrepairingdamagecomponentmoreattractive.VariousrepairtechniquessuchasElectronbeam,Laser,Coldspray,Lowheatinput,Diffusionbonding,Widegapbrazing,PlasmasprayandGasTungstenArcWeldingarebeingused.AmongstthesemethodsthewidelyunderstoodandmorefamiliartechniquewhichismorecosteffectivetorepairindustriesisGasTungstenArcWelding.However,afterrepair,thereisvaryingfatiguedatafortheserepairedcomponents.Someoftherepairedcomponentshavecomparativelygoodmechanicalpropertiesasthebaselinematerialwhilesasothershaveinferiormechanicalpropertiescomparedtothebaselinematerial.Thesedisparitieshavebeenidentifiedaslackofrepairprocessoptimizationthatcausesdefectsintherepairedcomponent.Thisimpliesthatextrafailuremechanismsarepresentintherepairedcomponentwhichaccountsfortheinferiorfatiguepropertieswitnessedinsomeoftherepairedcomponents.Itisthereforeimperativetoidentifywhatthesefailuremechanismare,howtheyoccurandinwhichareasoftherepairedcomponentstheyarenoted.Thisknowledgewillbetterequiptheengineertobeabletoselectthebestrepairtechniquesandprocessparameterstominimizetheeffectofthesefailuremechanismsintherepairedcomponents.ThemainobjectiveofthisresearchistoidentifythefailuremechanismpresentintherepairedcomponentsinbothPolycrystallineIN738andDSR80.

[28] MICROCONSTITUENTSCAUSINGWELDHEATAFFECTEDZONEMICROFISSURINGININCONEL738SUPERALLOY Amegadzie,MarkYao,M.Sc.CandidateMechanicalandManufacturingEngineeringAdvisors:Dr.M.C.ChaturvediandDr.O.A.Ojo Inconel738isoneofthemostwidelyusedheatresistantalloysforthehotsectioncomponentsofaeroandindustrialgasturbines.Thealloy,however,isextremelydifficulttofabricateandrepairbyfusionweldingduetoitshighsusceptibilitytoheataffectedzone(HAZ)intergranularmicrofissuring.Inthepresentwork,theHAZmicrostructureintungsteninertgasweldedIN738superalloywascarefullystudiedbyelectronmicrocopytechniquestoidentifythemicroconstituentsthatareresponsibleforthehighsusceptibilityofthematerialtomicrofissuring.TheHAZcrackingwasobservedtobecloselyassociatedwitheutectic‐typeliquationreactionofsolidificationproductspresentinthecastalloy,includingMC‐typecarbides,M2SCsulpho‐carbidesandM3B2borides.Inaddition,non‐equilibriumliquidphasedissolutionofthemainstrengtheningofthesuperalloy,γ'precipitates,wasfoundtobeanothervitalfactorcontributingtothelowresistanceofthematerialtocrackingunderthermallyinducedweldingstresses.Theresultsoftheinvestigationwillbepresented. [29] FATIGUEBEHAVIOROFANEWLYDEVELOPEDAEROSPACESUPERALLOYHAYNES282 Buckson,Richard,Ph.D.CandidateMechanicalandManufacturingEngineeringAdvisor:Dr.O.A.OjoStrain‐controlledLowCycleFatigue(LCF)andFatigueCrackPropagation(FCG)testswerecarriedoutonanewlydevelopedAerospacesuperalloy,Haynes282,initsstandardheattreatmentcondition.LCFtestresultsdemonstratedthatHaynes282exhibitedarelativelyshortperiodofinitialcyclichardeningfollowedbyaregimeofcyclicsofteningtospecimenfailureatallthestrainamplitudesemployedinthework.Anincreaseinthestressratioleadtoanincreasedcrackpropagationrate.However,incontrasttocommonassumptions,theloadingfrequencywasobservedtohaveaninfluenceonthecrackgrowthbehaviour.Thecyclicdeformationparametersdeterminedintheworkindicatestrongfatiguedeformationresistanceofthenewlydevelopedsuperalloy. [30] IMPROVINGTHEOXIDATIONBEHAVIOUROFANICKELBASEDSUPERALLOYPRODUCEDBYPOWDERMETALLURGYMurray,D.Clark,M.Sc.CandidateMechanicalandManufacturingEngineeringAdvisors:Dr.N.L.RichardsandDr.W.F.CaleyNickelbasedSuperalloysareoftenusedinapplicationsthatrequirebothhightemperaturestrengthandexcellentoxidationresistance.Thehightemperaturestrengthofthesematerialsisoftenfoundthroughaγ'phase(Ni3Al)inthesealloysandoxidationresistance

issaidtodramaticallyimprovethroughminoradditionsofreactiveelements.InthepresentresearchaNi‐12Cr‐9Fe(w/o)masterpowderhasbeenblendedwithalubricantandcombinationsofaluminum,siliconandyttriuminanefforttoqualifyandquantifytheoxidationresistanceofthevariouscompositions.Thetransverserupturestrength(TRS)barshavebeenproducedthroughthemethodsofcolduni‐axialdiecompaction,anintermediatetemperaturelubricantremovalstageandfollowedbyasinteringprofilepreviouslydeveloped(1300°Cw/2hhold).Thedensityofthemajorityofcompactspostsinterwasapproximately80%.Inanefforttoincreasethedensityofthesecompactspriortooxidation,Gleeblethermo‐mechanicaldeformationhasbeenperformed.Thisdeformationhasyieldeddensitiesinthecompactsofapproximately90%althoughthe¥'strengtheningphasefoundinmanyNi‐basedSuperalloyswasnolongernotedthroughmicroscopy.Variousheattreatmentprocedureswillbeperformedonthedensifiedcompactsinanefforttorestoretheγ'phasetothemicrostructure.Subsequentlythecompactstheywillbesectionedintocouponsandoxidizedat900°Cthroughstaticoxidationfortimesupto1000h.Therolesoftheelementalpowdersaddedtotheternarysysteminprovidingoptimumoxidationresistancemaythenbeassessed.[31] PROCESSINGOFAEROSPACESUPERALLOYSTHROUGHLINEARFRICTIONTECHNIQUEOla,Oyedele,Ph.D.CandidateMechanicalandManufacturingEngineeringAdvisors:Dr.M.C.ChaturvediandDr.O.A.OjoLinearfrictionwelding(LFW)isarelativelynewandstate‐of‐the‐artprocessforjoiningaerospacematerialsthatareverydifficulttoweld.Thesematerialsincludepolycrystalline,directionallysolidifiedandsinglecrystalnickel‐basesuperalloysusedinmanufacturinghotsectioncomponentsofaerospacegasturbineengines.LFWisespeciallyattractiveforjoiningthesematerialsduetoitseffectivenessineliminatingamajorlimitationofconventionalfusionweldingprocesses,whichisgrainboundaryliquationcracking.However,LFWproducessomemicrostructuralanomaliesthathavebeendifficulttoexplain.Thegoalofthisworkwastostudy,andunderstand,thedevelopmentofthesemicrostructuralanomalies,whichiscriticaltoimprovingthejoiningprocedureandmechanicalpropertiesoflinearfrictionweldedjointsinnickel‐basesuperalloys.Theresultsofthisworkwillbepresented.[32] ELECTRONMICROSCOPYIDENTIFICATIONOFM5B3BORIDEANDITSEFFECTONMECHANICALPROPERTYINHY282SUPERALLOYOsoba,Lawrence,Ph.D.CandidateMechanicalandManufacturingEngineeringAdvisor:Dr.O.A.OjoHaynes282isanewγ'strengthenednickel‐basesuperalloydesignedforhightemperatureapplicationsinaerospaceandpowergenerationturbineengines.Thepropertiesandperformanceofmaterialsdependontheirinitialmicrostructureorthosedevelopedinservice.Therefore,themicrostructureofthenewlydevelopedHY282superalloyinthefullyheattreatedconditionwascarefullystudiedusingelectronmicroscopytechniques.In

additiontoM23C6andMC‐typecarbideparticlespreviouslyreportedtobepresentinthealloy,precipitatesbasedonanewphase,M5B3boride,whichhasnotbeenreportedinthenewalloywereidentifiedalongtheintergranularregion.FormationofthegrainboundaryM5B3borideswasfoundtosignificantlyreducetheductilityofthenewalloyathightemperatures.Incontrasttowhatisexpectedbasedonsolid‐statereaction,thepresentstudyshowedthatapossiblewayofmitigatingagainsttheductilitydamagecausedbytheboridesisbyincreasingthegrainboundarysurfaceareainthealloythroughthermo‐mechanicallyinducedgrainrefinement.Theresultsofthestudywillbepresented. LiquidandSolidCrystals [33] ALIGNMENTANDSELF­ASSEMBLYOFSURFACE­FUCTIONALIZEDGOLDNANORODSINLIQUIDCRYSTALSFeng,Xiang,Ph.D.CandidateChemistryAdvisor:Dr.T.HegmannThesignificantinterestinanisometricnanomaterialsarisesfromtheiruniqueopticalandelectronicpropertiesthatcaneasilybetunedthroughsmallchangesinsize,structureandshape.However,thefabricationoforientationalorderedarraysofanisotropicnanoparticlesfromthebottomupremainsachallengingquest.Toaddressthisproblem,wedispersedhydrophobicgoldnanorodscoatedwithorganosilanesinliquidcrystalsphases(nematicandcolumnar)andutilizeddifferenttypesofsurface‐modifiedsubstratestoobtainplanar(homogeneous)orhomeotropicalignmentofliquidcrystalsandthedispersedgoldnanorods.Thequalityofliquidcrystalandnanorodalignmentwerecharacterizedbypolarizedopticalmicroscopyandpolarizedvisiblespectrophotometry,respectively.Here,surface‐functionalizedgoldnanorodsproducedviaacoatingexchangefromCTAB(cetyltrimethylammoniumbromide)tofunctionalizedliquidcrystallinemoietiesarethoughttofacilitatetheself‐assemblyandlarge‐scalealignmentofthenanorods. [34] MAGIC-SIZEDCdSeNANOCRYSTALSINANEMATICLIQUIDCRYSTAL Mirzaei,Javad ,Ph.D.CandidateChemistryAdvisor:Dr.T.HegmannDispersionsofmetallicandsemiconductornanoparticlesinnematicliquidcrystals(NLCs)canhaveuniqueeffectsontheelectro‐opticpropertiesoftheNLChost[1].Suchparticlesalsoimpacttheopticalcharacteristicsincludingthinfilmtexture,molecularalignmentanddefectformation.[2]Herein,wereportontheeffectsofthreetypesofquantumdots(QDs),fromafamilyofmagic‐sizedCdSesemiconductornanocrystalsexhibitingabrightbandgapphotoluminescencewiththemaximumintensityat463nm,ontheoptical,alignmentandelectro‐opticpropertiesofaNLCandcomparingtheresultswithexistingdata[3‐4]fromothertypesofparticles.SeveralmixturesoftheNLCdopedwithsmallquantitiesofsuchQDshavebeenprepared,andtheopticalaswellaselectro‐opticpropertieshavebeen

studied.Here,fluorescenceconfocalpolarizedmicroscopyhasproventobeanindispensabletooltoelucidatetheeffectsoftheseluminescentparticles.1)H.QiandT.Hegmann,J.Mater.Chem.,2006,16,4197‐4205.2)T.Hegmann,H.QiandV.M.Marx,J.Inorg.Organomet.P.,2007,17,483‐508.3)B.KinkeadandT.Hegmann,J.Mater.Chem.,2010,20,448‐458.4)M.Urbanski,B.Kinkead,T.HegmannandH.‐S.Kitzerow,LiquidCrystals,2010,37,1151‐1156. MicroelectricalmechanicalSystems(MEMS) [35] ESTIMATINGTHESAMPLEINTERACTIONVOLUMEINDYNAMICHETERODYNEDELECTROSTATICFORCEMICROSCOPY Anema,Everet,M.Sc.CandidateElectricalandComputerEngineeringAdvisor:Dr.D.Oliver Theelectricforcemicroscope(EFM)isauniquetoolthatspatiallymapselectricalpropertiessuchassurfacecharge.Thistechniquealsoallowsfortheinspectionoflocalvariationsinthepermittivityofmaterial,avariationthatisnotrestrictedtothesurfaceofthematerial.TheprimaryobjectiveofthisprojectwastodeterminethevolumeofmaterialthattheEFMtipwasinteractingwith.ThisobjectivewasaccomplishedusingfieldtheorytopredicttheelectricfieldinsidethechamberoftheEFMandwiththepredictedfieldscalculatetheportionofthematerialthatisresponsibleforthemajorityoftheforce.Tovalidatethemathematicalmodelsitwasnecessarytocomparetheresultswiththeactualexperimentthatwasmodelled.TheexperimentswereconductedinvacuumusingdynamicheterodynedEFMapproach.Thistechniqueappliesanamplitudemodulatedsignaltothetipandobservesthevariationinresonantamplitudetodeterminetheforceactingonthetip,andfromthistheelectricalpropertiesofthematerial.ThesampleusedwasthecalibrationgratingTGZ‐01/02/03manufacturedbyMikroMasch.ThesesamplesconsistofanSisubstratewithaseriesofSiO2stepsofvaryingheights.ThesesampleswereusedtochangetheratioofSitoSiO2inthematerialdirectlybelowthetip.Twomodelswerecreated,oneanalyticalandthesecondusingCOMSOL,afiniteelementpackage.Thetwomodelshavefairlygoodagreementwitheachotherbasedontheforceactingonthetip;theydifferbyabout8%.Anestimateofthisforcebasedonexperimentaldataiswithinanorderofmagnitudeofthevaluesobtainedusingthemodels. [36] POLYMER­BASEDMEMSCHEMICAPACITORSENSOREmadi,Arezoo,Ph.D.CandidateElectricalandComputerEngineeringAdvisor:Dr.C.ShafaiPromisinggasdetectorsarepolymer‐basedsensors,whichbenefitfromavastrangeoforganicpolymersthatreactdifferentlytoadesiredvolatile.Traditionallypolymer‐basedsensorsutilizeacompositefilmofaninsulatingpolymertogetherwithconductivefiller,andresistancemeasurementsareperformedtostudythesensorresponsetoadesired

analyte.However,itisobservedthatanytemperaturevariationalterssensorsensitivityandcausesanerrorinthesensorresponse.Toovercomethisdisadvantage,anothersensorstructureisproposedandfabricated.Theproposeddesignemploysamicro‐resistiveheaterthatmaintainsaconstanttemperaturethroughoutdevice.Theresistiveheateralongwithinterdigitatedelectrodesisfabricatedonathinsiliconplatformandcapacitivemeasurementscanbeperformedtoinvestigatethepresenceofvolatile,therefore,thereisnoneedforconductivefillerinthesensingfilm.Averylowcostandhighaccuratecapacitance‐to‐digitalconvertorcanbeutilizedtoconvertthemeasuredcapacitancetoadigitalsignal.Themicro‐heatercanbebiasedtoeffectivelyachieveandmaintainthedesiredtemperatureaboveambienttemperature.Differentgeometriesareconsideredtodesignanefficientstructurewithoptimumrequiredinputpowerandminimumtemperaturevariationacrosssensingarea.Differentmicro‐heaterlocationandshapesareinvestigatedastheheatingelement.3DCOMSOLheattransfersimulationsindicatecantileverstructurewithheateratonesideandlocatedtowardendoncantileverastheoptimumstructure. [37] ANALYZINGDIRECTIONALLEUKOCYTEMIGRATIONUSINGMICROFLUIDICDEVICESLi,Jing,M.Sc.CandidatePhysicsandAstronomyAdvisor:Dr.F.LinImmunecellmigrationisafundamentalprocessthatenablesimmunosurveillanceandimmuneresponses.Understandingthemechanismofimmunecellmigrationisnotonlyofimportancetothebiologyofcells,butalsohashighrelevancetocelltraffickingmediatedphysiologicalproblemsanddiseasessuchasembryogenesis,woundhealing,autoimmunediseasesandcancers.Immunecellmigrationcanbedirectedbydifferentenvironmentalfactorssuchaschemicalconcentrationgradientsthroughaprocesscalledchemotaxis.Inadditiontochemicalgradientdirectedcellmigration,directcurrent(DC)electricfieldscanbegeneratedinvivoandinvitro,andsuchelectricfieldscanalsoguidethemigrationofimmunecells(i.e.electrotaxis).Conventionalcellmigrationassaysaregenerallylackofcontrolforconfiguringextracellularenvironmentsandconsumelargeamountofreagents.Recentdevelopmentofmicrofluidicdevicesoffersanovelapproachforstudyingcellmigrationunderminiaturizedandwell‐controlledexperimentalconditions.Thefocusofthepresentstudyisonapplyingmicrofluidicsystemstoquantitativemeasurementandanalysisofimmunecellchemotaxisandelectrotaxis.Usingasimplemicrofluidicdevicethatcanproducedefinedandstablechemoattractantgradients,wedemonstratedchemotaxisofhumanneutrophilsandTlymphocytestodifferentchemokinegradients.Furthermore,weshowedthatneutrophilchemotaxistoachemokinegradientwithphysiologicallyrelevantprofilescanbemeasuredatthesinglecelllevelinthemicrofluidicdevicebydirectlyloadingjustadropofbloodtothedevice.Inadditiontochemotaxis,wedevelopedmicrofluidicdevicesthatcangenerateuniformdirectcurrentelectricfields.Usingthesedevices,weinthefirsttimedemonstratedelectrotaxisofactivatedhumanTlymphocytes.Thisfindingisconsistentwithpreviouselectrotaxisstudiesonotherleukocytesubsetssuggestingelectrotaxisisanovelguidingmechanismsforimmunecellmigration.Insummary,ourstudyprovidesnovelmicrofluidictoolsforanalyzingimmune

cellmigrationdirectedbychemicalandelectricalcues. [38] AMEMSELECTRICFIELDSENSOROPTIMIZATIONBYMULTI­OBJECTIVENICHEDPARETOGENETICALGORITHMRoy,Mark,M.Sc.CandidateElectricalandComputerEngineeringAdvisor:Dr.C.ShafaiMicro‐electro‐mechanicalsystems(MEMS)havetraditionallybeenoptimizedmanuallybasedonthesolutionstodynamicequationsandintuition.Thispaperpresentstheapplicationofamulti‐objectivenichedParetogeneticalgorithmtooptimizeasynthesizeddesignofaMEMSelectricfieldsensor.Thegeometryofthesensordesignisvariedinordertomeettheobjectivesofmaximaldisplacement,minimalstress,minimaltemperatureandaresonantfrequencynear2kHz.ThealgorithmgraduallyevolvesasetofsolutionstowardsaParetosetinwhichnosolutionisbetterinallobjectivesthananyothersolution.Whenthealgorithmhasfinishedthedesignermaychooseoneormoresolutionsfromthesetwhichbestmeetstheirobjectivesallowingthemtoseetheavailabletrade‐offs.Theresultsshowcomparableorbetterperformanceinsimulationthandevicesoptimizedmanuallyorbyothermeans.[39] MICROWAVESENSORFORTHEDETECTIONOFSINGLESUPERPARAMAGNETICMICROBEADSINAMICROFLUIDICDEVICEFORUSEINBIOPARTICLESEPARATIONANDCOUNTINGRzeszowski,Szymon,M.Sc.CandidateElectricalandComputerEngineeringAdvisor:Dr.G.BridgesAppropriatelycoatedmagneticmicrobeadsareareliableandgentlewayofisolatingspecificbioparticlesfromasampleandhavebeenwidelyusedinlaboratoriesfordecades.Thisistypicallyperformedonlargevolumesamplesinvolvingmillionsofparticles.Microfluidicsenablesthemanipulationandcontroloffluidsatthenanolitrevolumescale,andincombinationwithappropriatemicroelectronics,enablestheintegrationandautomationofvariouslaboratoryprocessesontoasingledevice,includingsinglebioparticledetectionandmanipulation.Thedetectionofasinglemagneticmicrobeadiscriticalfordetectingsinglebioparticles.Wepresentahighfrequencyinductancesensorthatiscapableofdetectingsingle4.5µmsuperparamagneticbeadsastheyflowinsidea25µmdeepchannel.Thesensorisbasedonamicrowaveinterferometerandaresonatorterminatedbyaloop‐shapedelectrodeatthebottomofthemicrofluidicchannel.Thesensorcandetectinductancechangesasamagneticbeadpassesoverloopelectrode.Thesuperparamagneticbeadsweemployarecomposedofsingle‐domainnanoparticlesofiron‐oxideembeddedinapolymermatrix.Thehigh‐frequencymagneticpropertiesofthesebeadsarelargelyuntestedandthissensorprovidesinsightintotheirmagneticpermeabilityatafrequencyof1.5GHz.Althoughvariousothermagneticsensorshavebeendeveloped,ourapproachdoesnotrequireanadditionaldcbiasingmagneticfield,whichisadvantageousformicroelectronicfabrication.

[40] ATUNABLEMEMS­ENABLEDFREQUENCYSELECTIVESURFACESafariHassanAbadi,Mojtaba,M.Sc.CandidateElectricalandComputerEngineeringAdvisor:Dr.C.ShafaiAfrequencyselectivesurface(FSS)basedonswitchableslotsonthegroundplaneispresented.TheswitchingisdoneusinganactuatingMEMSbridgeovertheslot.TheintentistodemonstratethecontroloftheresonancefrequencyoftheFSSbydeflectingthebridge.Itisshownthatbyapplyingavoltagebetweenthebridgeandthegroundplane,thebridgedisplacesandchangesthecapacitanceofthesystemwhichinturnchangestheresonancefrequency.Twoanalysesarepresented,(1)Electromechanicalanalysistoshowhowthebridgedeflectsbythevoltage,(2)EManalysistoshowhowtheresonancefrequencychangesbythebridgedeflection.ThemeasurementresultsfortwoupanddownpositionsoftheMEMSbridgearegiven,whichshowagoodagreementwithsimulationresults. [41] QUASI­STATICOPTIMIZATIONOFAMICROMACHINEDELECTRICFIELDMILLZhou,Yu,M.Sc.CandidateElectricalandComputerEngineeringAdvisor:Dr.C.ShafaiAmicromachinedElectricFieldMill(MEFM)hasbeendevelopedandhasshowncapableofmeasuringbothdcandacelectricfields.Thesensoroperatesbyusingthermalactuatorstooscillateaperforatedgroundedshutteroverunderlyingelectrodes.Inthispresentation,anewgenerationofsensorisinvestigated,werethedimensionsoftheperforationsintheshutterareoptimizedtomaximizesensorresolution.Quasi‐staticelectricfieldchargingofsenseelectrodeshasbeenexploredtomaximizethechargingsignal.Simulationshaveshownthattheinducedchargeontheelectrodes,thereforethecurrentsignal,isdependentontheinverseofthegapbetweentheshutterandelectrodes,anddependentonthesizeofperforationsintheshutteraswellasthespacingbetweenperforations.Thecurrentsensordesignalsosuffersfromchargingeffect,whichreducessensorsensitivityovertime.Shieldingoftheelectrodes,bymeansofagroundedguardingringisinvestigated.Presentedsimulationsdemonstratethattheguardingringcangreatlyreducethefringingfieldattheedgeoftheshutter.Thiswillhavethebenefitsofreducedcharging,aswellasreducedelectricfieldinterferencefromthermalactuatorswhichwillincreasesensorresolution. PhotonicandPhononicInteractions [42] USINGASPINTRONICMICROWAVESENSORTOSEETHEINVISIBLECao,ZhongXing,Ph.D.CandidatePhysicsandAstronomyAdvisor:Dr.C.‐M.Hu

Microwavepropagationinadielectricmediumunderliesallresponsesofmicrowaveenergyinteractionwiththedielectricsystem.Therefore,itisgenerallyacceptedthatthedielectricpropertiescanbeaccuratelyreconstructedbycharacterizingthespatialdistributionofabsorbedmicrowaveenergy.Forthispurpose,boththeamplitudeandthephaseofmicrowavefieldsareessentialinordertodeducethecomplexdielectricconstantofmaterialsduetoenergyloss.Theadvantageofmicrowavesisthattheycanpenetrateintotheobjectandenablethedetectionsof‘hiding’objects,whichisimportantforhealthcareandsecurityapplications.However,themicrowavewavelengthiscomparableorevenlargerthanthesizeofobjectsundertest,therefore,suchsub‐wavelengthfeaturesarerestrictedtothenear‐field.Thedevelopmentofspintronictechniquesshineslightonthedetectionoftheinteractionbetweenmicrowaveanddielectricmaterials,especiallyduetoitsphase‐resolvedcapability.Incontrasttotheamplitudewhichiseasilymeasuredbyaconventionalstaticortime‐averageapproachsuchasapowermeter,conventionalphasemetershaveanupperfrequencylimitofafew100kHzimposedbytheabilityofelectroniccircuitsunderhigh‐speedoperation.Veryrecently,anovelsensorhasbeeninventedinourgroup,whichhasbothamplitude‐andphase‐resolvedcapabilitiesforprobingmicrowavefields.Furthermore,duetothesub‐mmsizeofsuchaspintronicsensor,itcanbesituatedveryclosetothesamplefornear‐fieldimaging.Theinteractioninthesub‐wavelengthscalebetweenmicrowavesanddielectricmaterialscanthereforebedetected.Inthisposter,wedemonstrateboththephaseandamplitude‐resolvedcapabilitiesofthissensor,thesub‐wavelengthfeatureofobjectsinvisibletotheeye,aswellasthedielectricdependenceoftheimaging. [43] SERSIMAGINGOFFUNGIWITHGOLDNANOPARTICLESSYNTHESIZEDINVIVOFarazkhorasani,Fatemeh,Ph.D.CandidateChemistryAdvisor:Dr.K.M.GoughMetalnanoparticlesareofgreatinterestbothfundamentallyandtechnologicallyduetotheiruniquechemicalandphysicalpropertiescomparedtotheirbulkcounterparts.Fungiareabletoreducemetalsandproducevariousintracellularandextracellularmetalcolloidswithouttheneedforexternalreducingreagents.Fungihavepervasiveandessentialrolesinplantsurvivalthatincludesymbioticrelationshipswhereinfungitradeservicesforfood.Theyalsoincludesomeofthemoredeadlypathogensthatthreatencropsandhumanhealth;othersparticipateinsymbioticrelationshipswithplants,helpingthemacquirenutrientsfromsoils.Thesesubstantialpositiveandnegativeimpactsoffungionhumanandecosystemactivitiesnecessitatebetterunderstandingoffungaldiversity,biology,andecology.IncubationofAspergillusnidulanshyphaewithaqueouschloroaurateresultsinrapidinvivosynthesisofgoldnanoparticles(AuNPs)withinandonthehyphalsurface.CompositionasAuNPisconfirmedbyscanningtransmissionx‐raymicroscopy.TransmissionelectronmicroscopyimagesofcellsafterincubationvividlyshowtheformationofAuNPs,ranginginsizefromafewnmtoseveralmicrons.Largerparticlesaretrianglesorirregularhexagons,whilesmallerparticlesappeartobeglobular,and~10‐50nmindiameter,hencesuitableforSERS.MostoftheAuNPswereassociatedwithhyphalwalls,bothinthecytoplasmandontheouterwallsurface.SERSspectraarereadily

generatedfromthesesamplesandanalysisisongoing.WenowseektorestrictNPformationtocellwall,inaseriesofAspergillusmutantswithsignificantvariationsinwallmorphology.OurlateststudiesonpH,temperature,metalconcentration,exposuretimeandstartingbiomassillustratetheimportanceoftheseparametersforthecontrolofNPformation(sizeandlocation)whilemaintainingadequatecellviability. [44] OBSERVATIONOFBRAGGANDHYBRIDIZATIONGAPSIN2DPHONONICCRYSTALSLee,EricJinSer,Ph.D.CandidatePhysicsandAstronomyAdvisor:Dr.J.H.PageThereisgrowinginterestinthepropertiesofphononiccrystals[1‐4],whichmayexhibitbandgapsduetoBraggscattering[1,2]and/orahybridizationmechanism[5‐7].Recently,thecoexistenceofahybridizationgapandaBragggapatdifferentfrequenciesina3Dphononiccrystalhasbeenreported[7].Here,wefocuson2Dcrystals,wherethelatticeconstantacanbetunedbychangingtheseparationbetweenthescatterers.Sincethebandgapfrequenciesforthesetwotypesofgapdependdifferentlyona,theirdifferentphysicaloriginscanbedistinguishedexperimentally.Weobservebothtypesofgapsseparately,andalsothecompetitionbetweenthehybridizationandBraggmechanismswhentheyoccuratsimilarfrequenciesinthesamecrystals.Here,transmissionexperimentstoinvestigatethebandstructurewereconductedinawatertankusingpairsofidenticaltransducersspanningthefrequencyrangefrom0.5to4.0MHz.Furtherconfirmationofthedifferentcharacterofthehybridizationgapsinourcrystalswasrevealedbycomparisonwithrandomsamples.Thehybridizationgapsarerobustinthattheyoccurinallsamplesatsimilarfrequencies,whileBragggapsaredestroyedbydisorderandshiftinfrequencyasthelatticeconstantisvaried.Inthehybridizationgaps,thegroupvelocitywasfoundtobenegative,withthiseffectbeingespeciallypronouncedinthephononiccrystalscomparedwiththerandomsamples.References:[1]A.Sukhovich,L.Jing,andJ.H.Page:Phys.Rev.B77(2008)014301.[2]S.Yang,J.H.Page,Z.Liu,etal.:Phys.Rev.Lett.88(2002)104301.[3]S.Yang,J.H.Page,Z.Liu,etal.:Phys.Rev.Lett.93(2004)024301.[4]A.Sukhovich,B.Merheb,K.Muralidharan,etal.:Phys.Rev.Lett.102(2009)154301.[5]X.D.Jing,P.Sheng,andM.Y.Zhou:Phys.Rev.A46(1992)6513.[6]X.Zhang,Z.Y.Liu,F.G.Wu,etal.:Phys.Rev.E73(2006)066604.[7]T.Still,W.Cheng,M.Retsch,etal.:Phys.Rev.Lett.100(2008)194301. SoftandDisorderedMaterials [45] DRUGCONTAINING,ANTIMICROBIALMICRO­ANDSUBMICRO­POLYUREACAPSULESBASEDONINTERFACIALCROSSLINKINGOFPOLYETHYLENIMINEHe,Wei,M.Sc.CandidateTextileScienceAdvisor:Dr.S.Liu

Narrowly‐dispersedpolyureacapsulesinthediameterrangeof0.2µm‐5µmcanbesynthesizedfrompolyethylenimineanddiisocyanateviainterfacialcrosslinkingwithoil‐in‐oilemulsioncarriedoutunderroomtemperatureforashortperiodoftime(10min).Differentsolventssuchaswater,ethanol,DMFcanbeadoptedasdispersephase.Themildreactionconditionsandtheflexibilityinsolventselectionallowawideselectionofantimicrobialdrugs,nutrients,andgrowthfactorsforencapsulation.Incaseofcortisone,amodelhydrophobicdrug,loadingcapacityandefficiencyare26wt%and57%respectively.Theencapsulateddrugcanbereleasedat37degreeCelsiusforover7days.Theprocesscanberegulatedtoleavespecificamountsofisocyantegroupsonthemicrocapsuleaftersynthesissoanantimicrobialmoietysuchasquaternaryammoniumcompound(QAC)canbeconvenientlyattachedtothesurfaceofthecapsulesinashortperiodoftimeavoidingleachingoftheencapsulatedbioactiveagents.ThegraftedQACcanendowthecapsuleofsurfaceantimicrobialactivityaspositivelychargedofQACcanattractnegativelychargedbacteriaandcausedisruptionofcellmembranes.TheQACgraftedcapsulesdemonstrated61%reductionofE.coliafter30minutescontactwiththebacterialsuspensionatroomtemperature. [46] TRANSVERSECONFINEMENTOFELASTICWAVESNEARTHEEXPECTEDLOCALIZATIONTRANSITIONINAHIGHLYPOROUSGLASSNETWORKStrybulevych,Anatoliy,PostdoctoralFellowPhysicsandAstronomyAdvisor:Dr.J.H.PageGiventherecentsuccessfulexperimentalobservationoftheAndersonlocalizationofelasticwavesinathree‐dimensionalnetworkofaluminumbeads[1],theinvestigationofwavetransportinsimilarsystemsisofconsiderableinterest.Inthisposter,weuseultrasonictechniquestostudydeparturesfromnormaldiffusivebehaviorinahighlyporousnetwork,withasolidvolumefractionofonly0.33,formedfromsinteredglassbeads.Atintermediatefrequencies,wherethewavelengthiscomparablewiththeporesizesinthemedium,verystrongscatteringisobserved,withvaluesofklforlongitudinalwavescloseto1.Previousmeasurementsinthissystemrevealedaplateauinthediffusioncoefficient,determinedbyfittingthepredictionsofthediffusionapproximationtothetimedependenceofthetransmittedintensity,overawiderangeoffrequencies[2].Tolookforpossibledeviationsfromnormaldiffusivetransportinthissystem,thetransversespreadingofatightlyfocusedinputbeamwasmeasuredontheoppositefaceofthesample.Themeansquarewidthofthetransverseprofileisfoundtoincreasewithpropagationtimemoreslowlythanexpectedfordiffusewaves,asignatureofrenormalizationofthediffusioncoefficientduetointerferenceeffectsthatcanleadtoAndersonlocalization.Asthefrequencyisincreasedfromtheloweredgeoftheintermediatefrequencyregime,thelong‐timetransversewidthdecreasesbutremainslargerthanthesamplethickness,indicatingthat,overtherangeoffrequenciesstudied,atransitiontolocalizedmodesisbeingapproachedbutnotyetreachedinthesemeasurements.[1]H.Hu,A.Strybulevych,J.H.Page,S.E.Skipetrov,andB.A.vanTiggelen,NaturePhysics,4,945‐948(2008).[2]J.H.Page,W.K.Hildebrand,J.Back,R.Holmes,andJ.Bobowski,Phys.Stat.Sol.(c),11,

2925‐2928(2004).[47] THEORETICALSTUDYOFTHEFLOWBEHAVIORINSIDEACYLINDRICALTUBEWITHGRAFTEDPOLYMERSSuo,Tongchuan,PostdoctoralFellowPhysicsandAstronomyAdvisor:Dr.M.WhitmoreAself‐consistentmean‐fieldtheoryofflowthroughacylindricaltubewithgraftedpolymersispresented.Thepolymerdensityprofilecanbecalculatedinthepresenceofanyfluidflowprofileand,conversely,thefluidflowprofilecanbedeterminedfromanypolymerprofile.Consequently,theycanbothbecalculatedinaself‐consistentmanner.Thenumericalresultsindicatethat,althoughthegraftedpolymerchainsarealwaysstretchedbytheflowfield,theoverallconcentrationprofilemayormaynotchangedcomparedwiththecasewithoutflow.Theconditionsunderwhicheachoccursarediscussed. [48] SINGLE­ANDDOUBLE­RESONANCENMRSTUDIESOFPHASESEPARATIONANDCRYSTALLIZATIONINMODELNUCLEARWASTEGLASSESWren,John,Ph.D.CandidateChemistryAdvisor:Dr.S.KroekerBorosilicateglassesarecommonlyusedintheimmobilizationofradioactivewaste.Howeverthepoorsolubilityofcertainfissionproductsrestrictswasteloadingincommercialglasses.Tobetterunderstandthenatureofphaseseparationandcrystallizationphenomena,wehaveinvestigatedaseriesofmolybdenum‐bearingborosilicateglassesmodeledontypicalindustrialwastecompositions.Double‐resonanceNMRmethodswereimplementedtoprobetheproximityofnetwork‐forming(11B,29Si)andnetwork‐modifying(133Cs,23Na)cations,correlatingpositivelywithphase‐separatedandhomogeneousglasses.Moreover,single‐resonanceNMRexperiments(95Mo,133Cs,23Na)arefoundtobeparticularlyvaluablefordetectingthepresenceofcrystallizationproductsprecipitatedfromtheglass,especiallywherediffraction‐basedtechniquesmaybelimitedbycation‐cationsubstitution,smallcrystalsizeandlowlevelsofcrystallinity.Inthemodelglassesunderinvestigation,previouslyunknownmixed‐alkalimolybdateswereidentifiedbyNMRinthecomplexphaseassemblagequenchedfromthemelt.Theresultscanbeinterpretedintermsofthedegreeofglasshomogeneity,akeyparameterinlong‐termchemicaldurability. SurfacesandInterfaces [49] RAMANSTUDYOFSPUTTEREDHFO2THINFILMSBelo,Gustavo,Ph.D.CandidateElectricalandComputerEngineeringAdvisor:Dr.D.A.Buchanan

ThecrystallinephaseofHafniumdioxide(HfO2)thinfilmsdepositedbymagnetronsputteringusingdifferentconditionsandpots‐depositionannealingareinvestigatedusingLinearRamanSpectroscopy.The250nmthinfilmsweredepositedusingHfmetalandHfOtargetswithAr:O2ratios1:4and7:0sccmrespectivelyandpowerdensity3.7W/cm2.Apost‐depositionrapidthermalannealing(RTA)wasperformedinallsamplesfor90sat600,400and800°C.RoomtemperatureRamanspectrafeaturesinthe100‐750cm-1spectralrangeareassignedtovibrationalmodesassociatedtothecrystallinestructure.TheobserveddatawerefittedtoasumofappropriatenumberofLorentziansandtheRamanbandswereidentifiedconsideringtheactivesymmetrymodesexpectedfromamonoclinicortetragonalphase.The as-deposited Hf targetfilmexhibitatetragonalphasewhiletheas‐depositedHfOtargetfilmisamorphous.Astheannealingtemperatureincreasesbothfilmsbecomeamorphousandat600°Cstartstocrystallizeinamonoclinicphase. [50] CONTROLLEDRELEASEOFDOXORUBICINFROMPHANDREDOXDUALRESPONSIVEPEG­REDUCIBLEPOLY(BETA­AMINOESTER)SCOPOLYMERICMICELLESChen,Jun,PostdoctoralFellowMechanicalandManufacturingEngineering/TextileSciencesAdvisors:Dr.M.XingandDr.W.Zhong ThegoalofthisstudyistodevelopandcharacterizeanovelpHandredoxdualresponsivemicelles.Thesemicelleswillpreservetheircore‐shellstructureunderphysiologicalconditionsbutwillsharplyrespondtoacidic,and/orreductiveenvironmenttorapidlyreleasetheirincorporateddrug.Thenovelcopolymercontainingdisulfidebondsineachrepeatunitofpoly(beta‐aminoester)swassynthesizedviaMichaeladditionpolymerizationfrom2,2'‐dithiodiethanoldiacrylateand4,4'‐trimethylenedipiperidineandmethoxy‐PEG‐NH2.ResultsofNMRandGPCcharacterizationssuggestedthatthecopolymermayhave2‐3PEGchainsasgrafttoformthestructureofReduciblePoly(beta‐aminoester)s‐g‐Poly(ethyleneglycol).PHandredoxsensitivitiesofthecopolymericmicelleswereevaluatedusingafluorescencespectrometryanddynamiclightscattering.Ananti‐cancerdrug,doxorubicin(DOX),wastrappedintothemicelles.TheexperimentsofinvitrodrugreleasefromtheDOX‐loadedmicellesconfirmedthatDOXreleasedfasterfrommicellesinaweaklyacidicenvironment(pH6.5)thanatpH7.4,orinthepresenceofhigherconcentration(5mM)ofreducingagent(DTT).Particularly,DOXwasfoundtoreleasefasterfromtheDOX‐loadedmicellesinanenvironmentwithbothstimuli(pH6.5and5mMDTT),thaninconditionswithonlyonestimulus(pH6.5or5mMDTT).MTTassayshowedthattheDOX‐loadedmicelleshadacomparativecytotocixitytotheHepG2tumorcellscomparedtoDOX,whileblankmicellesshowedaverylowcytotocixitytothetumorcells.TheconfocalimagesindifferenttimepointsconfirmedtheefficientintracellulardoxorubicinreleasefromtheDOX‐loadedmicelles. [51] CORROSIONBEHAVIOURATTHEHEAD/NECKINTERFACEOFARTIFICIALHIPJOINTSDyrkacz,Richard,Ph.D.CandidateMechanicalandManufacturingEngineeringAdvisor:Dr.U.Wyss

Metal‐on‐metal(me‐on‐me)hipprostheseshavebeenknowntodisplaybetterwearbehaviourthanmetal‐on‐polyethylene(me‐on‐PE)hipprostheses.Forinstance,me‐on‐meimplantsexhibitmorethan100timeslessvolumetricwearingincomparisontome‐on‐PEimplants(noncross‐linkedPE),whensubjectedtothesameloadingandlubricationconditions.Me‐on‐meimplants,however,haveshowninsomecasestoleadtoadversetissuereactionstometalwearrequiringrevisionsurgery.Recently,itwasfoundthatmetalwearcanalsooriginatefromthehead/neckinterface,possiblyleadingtothesameadversetissuereactionsasmetalwearfromthearticulation.Thelong‐termpurposeofthisinvestigationistoassessthecorrosionandfrettingbehaviouratthehead/neckMorsetaperofme‐on‐meandme‐on‐PEmodularhipprostheses,andtoassesstheinfluenceofheadsizeonthecorrosionandfrettingbehaviour.Forthisstudy,36mmheadme‐on‐memodularhipprostheseswerecollectedfromtheImplantRetrievalAnalysisProgram(IRAP)databaseoftheConcordiaHipandKneeInstitute.Thecorrosionandfrettingofthehead/neckinterfacewillbepresentedusinganovelscoringmethod. [52] MULTIFUNCTIONALELECTROSPUNNANOFIBROUSSCAFFOLDSFORTISSUEENGINEERINGGao,Haiyun,M.Sc.CandidateTextileScienceAdvisor:Dr.W.Zhong Bymimickingthenativeextracellularmatrix(ECM),electrospunnanofibrousscaffolds(ENSs)canprovidebothchemicalandphysicalcuestomodulatecelladherenceanddifferentiationandtopromotetissueregenerationwhileretainingbioresorbableandbiocompatibleproperties.ENSscanalsobevehiclesthatcarrybioactivemoleculesortherapeuticagentstoenhancetissuehealingbyreleasingtheminasustainedandcontrolledway.Fromadevelopmentalbiologyperspective,healingisasynergicprocessthatinvolvesmultiplegrowthfactors,andgrowthfactor‐ladenscaffoldscanbeusedtocontrolstemcellfateandtopromotevascularization.

WedevelopedENSstodelivermultiplebiomoleculesbyloadingtheminthecore‐sheathstructureand/orbyconjugatingthemtothenanofibersurfaces.Inourwork,poly(L‐lactide)‐poly(ethyleneglycol)‐NH2(PLLA‐b‐PEG‐NH2)andpoly(L‐lactide)(PLLA)wereemulsionelectrospunintonanofiberswithacore‐sheathstructure.Amodeldrug,tetracyclinehydrochloride(TCH),wasloadedwithinthenanofibers.Aminoandcarboxylreactivegroupswerethenactivatedonthefibersurfacesusingsaturatedwatervaporexposureandbasehydrolysis,respectively.ThesereactivegroupsallowedthesurfaceoftheENStobefunctionalizedwithtwootherbioactivemolecules,FITC‐andrhodamine‐labeledbovineserumalbumins,whichwereusedasmodelproteins.TheENSswereshowntoretaintheirantimicrobialcapacityaftertwofunctionalizationreactions,indicatingthatmultifunctionalnanofiberscanpotentiallybedevelopedintofunctionalwounddressingsorperiodontalmembranesorusedinmorecomplicatedtissuesystemswheremultiplegrowthfactorsandanti‐infectionprecautionsarecriticalforthesuccessfulimplantationandregenerationoftissues. [53] SURFACE­ENGINEEREDPETVASCULARGRAFTSWITHIMPROVEDLONG­

TERMBIOCOMPATIBILITYLi,Jiang,M.Sc.CandidateTextileSciencesAdvisor:Dr.S.Liu Sincetherearemanycoronaryarterybypassgraftsurgerieseachyearandthesupplyofnativevesselsisinsufficient,syntheticgraftsbecomenecessary.WhenvasculargraftsmadeofsyntheticpolymerssuchasPETcomeincontactwithblood,theyareeasytooccludewhichisespeciallytrueforsmall‐diametergrafts.Sotheluminalsurfaceofvasculargraftsshouldinhibitplateletadhesionandthrombosisformation.Now,immobilizingheparin,ananticoagulatingagent,ontothesurfaceofbiomaterialsisacommonmethod.Toadaptthelong‐termuseofvasculargrafts,covalentlinkageisanidealimmobilizationmethodforheparin.However,chemicalmodificationofPETisachallengingtaskduetothechemicalinertnessandhighcrystallinityofPET.Besides,apropersurfacedensityofheparinisalsorequiredtoguaranteetheperformanceofthebiomaterials.MyprojectaimstodevelopPETvasculargraftswithideallong‐termbiocompatibilityinthesimplestoperation.WehavedurablyimmobilizedheparinontheinnersurfaceofPETvasculargraftsbasedonamodificationmethodofformingasurfaceinterpenetratingnetwork(IPN).Firstly,N‐(2‐aminoethyl)acrylamide(AEAM)wasco‐polymerizedwithadivinylcrosslinkeronthesurfaceofPETtoformtheIPN.ThistypeofIPNwasdefinedasthermoplasticsemi‐IPNandthesurfacemodificationproducedbythistechniqueisdurableexceptwhenthesubstratepolymerisdissolvedormeltedwhichwillnothappeninthisapplication.Then,heparinwasimmobilizedthroughstableamidebondswithAEAM.TheimmobilizationofheparinthroughAEAMhasbeenconfirmedbyXPSandtheamountofimmobilizedheparinquantifiedbythetitrationwithacationicdye‐‐‐ToluidineBluedye.Forthenextstep,ourworkistoobtainanoptimaldensityofheparinonthesurfaceandusebiologicaltesttodemonstratetheperformanceofPETvasculargraftsmodifiedinourlab. [54] HIGHRESOLUTIONULTRASOUNDIMAGINGMijaresChan,JoseJuan,Ph.D.CandidateElectricalandComputerEngineeringAdvisor:Dr.G.Thomas Ultrasoundflawdetectionisoneofthetechniquesusedinindustrialultrasonictesting.Flawdetection,wheninspectionisdonewithinthin‐layeredmaterials,canbecomeachallengingandtime‐consumingproblemsinceidentifyingtheechopatternsofafailuremayrequireeitherspecializedtrainingand/orperformsomesignalenhancement.Inthiswork,theuseofpulse‐echoultrasoundtestingwithsyntheticaperturefocusingandsignalprocessingtechniquestocreatehigh‐resolutionimagesoftheregionofinterestisdiscussed.Toovercomeanexcessivecomputationaltime,theuseofgraphicprocessingunitsisintroduced.Theproposedmethodwasdevelopedwiththeintentionofprovidingamorereliablesolutiontoidentifyingfaultswithindifferentdepthsofaspecimen.[55] EFFECTOFLOWPOWERDEPOSITIONANDLOWOXIDATIONTEMPERATUREONTHEQUALITYOFSPUTTEREDHFO2GATEDIELECTRICSMinko,Auxence,PostdoctoralFellow

ElectricalandComputerEngineeringAdvisor:Dr.D.A.Buchanan ThescalingofsiliconintegratedcircuithaspushedtheconventionalSiO2toitsphysicallimits.High‐kbasedgatedielectricisthepromisingstructureforthefutureofVLSIdevices.Recently,manycandidatessuchaszirconiumdioxide(ZrO2),aluminumoxide(Al2O3),andlanthanumaluminates(LaAlO3)havebeenextensivelydiscussed.Infact,highdielectricconstantfilmsofferthepotentialtomaintainthesamecapacitancevalueofathinSiO2whilereducing,byphysicallythickerfilms,theleakagecurrent.HfO2isconsideredasoneofthemostpromisinghigh‐kcandidates.HfO2filmshavebeendepositedbysputtering,bychemicalvapordeposition(CVD),andbyatomiclayerdeposition.WhileCVDandALDremainreliablebutexpensivewaystogrowhafniumdioxidedielectric,sputteringisalowcostalternativedepositionmethod.However,silicaorsilicateinterfaciallayersareinevitablyformedduringtheHfO2filmgrowthonsilicon.Inthiswork,athinHfO2filmpreparedbyDCmagnetronsputteringusingalow‐powerdepositionfollowedbyalow‐temperaturethermaloxidationshowgreatlyimprovedinterfacialandelectricalpropertiesofthegatestack.ThemeasurementsbyEllipsometryandX‐rayphotoelectronspectroscopy(XPS)showthegreatqualityofthepreparedHfO2film,witharefractiveindexof1.9andanoxygen/hafniumratioof2:1.TheTransmissionElectronMicroscopy(TEM)investigationshowsthatthethicknessofthenon‐desirableinterfacelayerisdramaticallyreducedtoapproximately1nm.Adielectricconstantof~22andalowleakagecurrentdensityof~10‐6A/cm2at1.3MV/cmhavebeenmeasuredbycapacitance‐voltage(C‐V)andcurrent‐voltage(I‐V)measurementsrespectively. [56] DRESSINGSOLUTIONTOBURNWOUNDS:ANTIMICROBIALANDNON­ADHESIVEWOUNDDRESSINGSPu,Tianyun,M.Sc.CandidateTextileSciencesAdvisor:Dr.S.Liu Burnwoundinfectionsisthemainreasonforthefailureofburntreatmentandmaybringlethalproblems.Amongburnwounddressing,thoseimpregnatedwithsilvershowgoodperformanceofinfectioncontrol.Thedesignofanewantibacterialandatraumaticdressingforthepurposeoftreatingburnwoundisquitenecessarybecauseanidealburnwounddressingshouldnotonlyavoidinfectionbutalsodonotadherewiththewoundornewformingepidermis.ThisprojectaimstodevelopanewuniversalmethodofdepositinghydrogelandAgNPs(silvernanoparticles)ontowounddressingssotoachievenewantibacterialandatraumaticdressings.Silverhaslongbeenusedasawide‐spectrumantibacterialagent,hydrogelhastheabilitytoabsorbwaterandkeepamoistenvironment,sothatitcanbeusedtopreventadhesivenesswhichiscausedbytheexudatesfromwound.PU(polyurethane)filmischosenasarepresentativeofwounddressingssinceitallowsphysicianstocheckthehealingofwoundswithoutremovingthedressingduetoitstransparency.Usingacylamide(AM),N,N'‐Methylenebisacrylamide(MBA,crosslinker)andbenzophenone(BP,initiator)tocarryoutphotoinitiatedsurfacemodification,PAMIPN(polyacrylamideinterpenetratingpolymernetwork)willbegraftedonPUpristinefilmcalledPAM‐PU.WithAM,MBA,KPS(potassiumpersulfate)andsilvernitrateforaheat

initiatedcrosslinkreaction,silverioncontainingPAMhydrogelcangrowonPAM‐PU,calledPAM‐gel‐PU.Afterimmersinginsodiumborohydridesolutionforreducing,nanosilver‐PAM‐gel‐PUwasobtained.Comparedwithsilverion,silvernanoparticleislesstoxictohumanskin.Hydrogelcanabsorb679%waterintermsofitsoriginalweightwhichmeansitcanwellabsorbexudatesfromwound.Fromantibacterialtest,after2hcontactwith10^7CFU/mlbacterialsuspension,99.99%MRSA40065(Methicillin‐resistantStaphylococcusaureus)werekilledbysilvernanoparticlethatindicatesthenanosilver‐PAM‐gel‐PUcaneffectivelycontrolinfectionandkillbacteria.Basedonthosepreliminaryresults,thenextstepforthisprojectistocarryoutacelldetachmenttesttoprovethatfibroblastcellsdonotadheretohydrogel.Treatmentofburnwoundsiscostlybothforthepatientintermsofreducedqualityoflifeandfinancially.Successfuldevelopmentofantimicrobialandnon‐adhesivedressingswillmakeavaluablecontributiontoimprovinghealingratesandthepatient'squalityoflife.[57] ELECTRICALCHARACTERIZATIONOFSEMICONDUCTINGMICROWIRESANDTHEIRJUNCTIONWITHIONICANDELECTRONICCONDUCTINGPOLYMERCOMPOSITESYahyaie,Iman ,Ph.D.CandidateElectricalandComputerEngineeringAdvisors:Dr.D.OliverandDr.D.Thomson Anewapproachfortheelectrical(DC)characterizationofsinglesiliconmicrowiresispresented.Theapproachinvolvesasoftcontactformationprocedureusingtungstenprobes.BasicelectricalpropertiessuchasDCresistivity(conductivity)ofthemicrowiresandalsothedopingdistributionalongthelengthofthemicrowiresmaybeinvestigatedusingthisapproach.Furthermore,thejunctionbetweenmicrowiresandconductingpolymersfortheuseinaproposedartificialphotosynthesissystemarealsostudied.Additions­LiquidandSolidCrystalsWITHDRAWN[58] DOPINGSMECTIC­CLIQUIDCRYSTALSWITHCHIRALNANOPARTICLES:NANOPARTICLESDECORATEDWITHSTRONGCHIRALINDUCERS Sharma,Anshul,M.Sc.CandidateChemistryAdvisor:Dr.T.HegmannLiquidcrystals(LCs)showlargevariationsinpropertieswhensubjectedtoelectricfields,polarisedlight,temperature,pH,andotherstimuli.Inthepresenceofanelectricfield,thechiralsmectic‐Cphase(SmC*)sandwichedbetweentworubbedpolyimide‐coatedglassslides(justafewmicronsthick)orientsinawaythatgivesrisetoaspontaneousferroelectricpolarization(PS)thatcanbeswitchedbetweentwosurface‐stabilizedstateswithfastresponsetimesandbistability.Suchsurface‐stabilizedferroelectricLCsarewidelyusedinvariousmicrodisplayapplications.UsuallySmC*LCsarepreparedbymixingachiraldopantofhighpolarizationpower

withanachiralsmectic(SmC)liquidcrystalmixture.Thepolarizationpowerisafunctionoftheeffectivetransferofchirality.AverypotentclassofchiraldopantswithatropisomericbiphenylcentralcoreshavebeendevelopedbyLemieuxetal.,andwereshowntoinducesomeofthehighestvaluesofthepolarizationpowereverreportedinphenylpyrimidineSmChostsfeaturinganidealstructuralmatch.[1]Toexploitthisstructuralmotifasnanoparticlecapping,wepreparedgoldnanoparticlesdecoratedwithsuchatropisomericbiphenylchiralmoietiestoserveasdopantsforLChosts.Basedonourpastworkon(S)‐naproxen‐cappedgoldnanoparticlesasdopantsinnematicLCs,[2]westudiedtheeffectivenessofthesechiralnanoparticlescappedwithatropisomersasdopantsforSmChosts.[1]RobertP.Lemieux,Acc.Chem.Res.2001,34,845.[2]HaoQi,JoeO’NeilandTorstenHegmann,J.Mater.Chem.2008,18,374.Additions­PhotonicandPhononicInteractions[59] Near­InfraredPropertiesofPPKTPandStoichiometricMgO:PPSLTCrystalsforHighPowerFemtosecondOpticalParametricOscillatorsZhao,Haitao,Ph.D.CandidateElectricalandComputerEngineeringAdvisor:Dr.A.MajorNonlinearmaterialiscriticalpointinbuildingafemtosecondopticalparametricoscillators(OPOs)innear‐infraredradiation,whicharepowerfulandindispensabletoolsformanyapplicationsthatrequirewavelengthtunability,shortpulseduration,highpeakpowerandhighrepetitionrate.Althoughperiodicallypoledlithiumniobate(PPLN)hasbeencommonlyusedforgenerationofnear‐IRirradiation,thelowphotorefractivedamagethresholdandhighcoercivefieldlargelylimititsoperatingrangeandoutputpower.Inthisworktwonewpromisingmaterials,periodicallypoledKTiOPO4(PPKTP)andperiodicallypoledstoichiometricMgO‐dopedLiTaO3(MgO:PPSLT)crystals,werestudiedtheoreticallytoassesstheirpotentialforthedesignofwidelytunableinfraredfemtosecondOPOsexcitedwithYb‐ionsolidstatelasers.TheopticalpropertiesaswellasthephasematchingandwavelengthtuningcharacteristicswerethoroughlyinvestigatedusingtheappropriateSellmeierequations.ThroughthechoiceofsuitablegratingperiodandtemperaturetuningboththePPKTPandMgO:PPSLTcrystalscanbedesignedtoprovideradiationfrom~1.3µmtotheirupperlimitoftransparencyrange.Moreover,thedispersivepropertiesincludinggroupvelocitydispersion(GVD)andgroupvelocitymismatch(GVM)werealsocalculated.Tothebestofourknowledge,thisisthefirstdetailedaccountofPPKTPandMgO:PPSLTcrystalpropertiesrelevanttoopticalparametricinteractionsinthenear‐IR.TheaimofthepresentedanalysisistoprovideathoroughreferenceforthedesignofpracticalPPKTP‐orMgO:PPSLT‐basedOPOspumpedbyhighpowerultrafastYb‐ionsolidstatelasers.

Additions­ComplexNaturalSystems[60] ANOVELWAYOFLOOKINGATTHECRYSTALSTRUCTUREPREDICTIONPROBLEM­ACASESTUDYOFTHEMILARITEGROUPOliverGagne,Ph.D.CandidateGeologicalSciencesAdvisor:Dr.F.HawthorneThegeneralfailuretomakereliablecrystalstructurepredictionsfromchemicalcompositionhaslongbeenidentifiedasacontinuingscandalinCrystallography.AlmostacenturyhaspassedsincethefamousX‐Raydiffractionexperimentthatresultedinthefirstcrystal‐structuresolution,yetthefactorsconstrainingcrystal‐structurearrangementsarestillnotunderstood.Probingthestabilitylimitsofmineralgroupsthatshowsolidsolutiongivesnewinsightintothecrystallizationprocess.Examinationofover350chemicalanalysesandstructurerefinementsofthemilaritegrouphasdefinedthecompositionallimitsofsubstitutionattheA,B,CandDsitesofthestructure.Therearecurrently21mineralsinthegroup,forming12rootcharge‐arrangements,plus14synthesizedcompositionsthatleadtoanadditionalone.Thestabilityoftherootcharge‐arrangementsmaybeexaminedwiththenewlydevelopedpredictivebond‐valencemethodology.Equationsderivedfromabondnetworkaresolvedinasystemofequationsinordertoobtainidealbond‐valencevalues,wherefeasibilitybecomesaquestionofwhetherthereisaspecificcombinationofcationsandanionsthatcansatisfythem.ThisisdeterminedfromanabsolutescanoftheInternationalCrystalStructureDatabase(ICSD),whereastatisticalsurveyforbondlengthsbyatom,oxidationstateandcoordinationnumberenablesustoassignabond‐valencerangestothepossiblecombinations.Therefore,fromapresetbondtopology,onecanobtainidealbond‐valencevaluesandassignpotentialelementstothesites.Customarybond‐valencetheorythenpermitsconversionofthebond‐valencevaluestocation‐aniondistances,optimizedwitha3‐Ddistance‐least‐squarescalculationtoobtainpossibleunit‐cellsoforderedatoms.Additions­ComplexCrystallineMaterialsandNanostructures[61] WORKFUNCTIONTUNINGOFREACTIVELYSPUTTEREDHf­Si­NMETALGATEELECTRODESFORADVANCEDCMOSTECHNOLOGY RekhaChaudhari,M.Sc.CandidateElectricalandComputerEngineeringAdvisor:Dr.D.BuchananDuetoaggressivereductionoftransistordimensions,theconventionalpoly‐silicongatedcomplementarymetaloxidesemiconductordeviceshaverevealedshortchanneleffects.Theconventionalpoly‐siliconisknowntosufferfromshortchanneleffectssuchaspolydepletion,highgateresistanceanddopantpenetration.Toreplacetheconventionalpoly‐

silicongate,extensiveresearchonworkfunctionengineeringofpotentialmetalgatesisbeingcarriedoutgloballytokeepupwiththescalingrequirementsforfutureCMOSdevices.Theabilitytotunetheworkfunctionofasinglemetalgatetechnology,overdesiredrangeishighlypreferable.ThepurposeofthisresearchistodiscoverthetuningoftheHf‐Si‐Ngateworkfunctionthroughtheincorporationofnitrogen.Metaloxidesemiconductor(MOS)capacitorsarefabricatedusingthermalSiO2asgateoxideonlightlydopedp‐typeSiwafer.HafniumandSilicontargetarereactivelyco‐sputteredat12mTorrinpresenceofN2andAr.ThegasflowratioRN=N2/(N2+Ar),isadjustedtovarythenitrogenconcentrationinHf‐Si‐Nfilms.ElectricalcharacterizationmeasurementswillbeperformedonallHf‐Si‐N/SiO2/SigatestackstoextracttheHf‐Si‐NworkfunctionandotherMOSdeviceparameters,includinggateoxidethickness,theacceptordopingconcentrationandflatbandvoltage.Interfacialbarrierheightswillbemeasuredusinginternalphoto‐emission(IPE)asanindependentconfirmationoftheHf‐Si‐Ngateworkfunction.Additions­HighTemperatureAerospaceMaterials[62] NUMERICALSIMULATIONOFSOLIDIFICATIONMICROSTRUCTUREINHYBRIDLASER­ARCSUPERALLOYWELDS Gao,Zhiguo,PostdoctoralFellowMechanicalandManufacturingEngineeringAdvisor:Dr.O.A.OjoAdvancedprocessingtechniquesandalloydesignhavebeenutilizedtoproducedirectionallysolidifiedandsinglecrystalnickel‐basesuperalloyswithimprovedelevatedtemperatureproperties,foraircraftengineapplications.Unfortunately,thenewgenerationsuperalloysareextremelydifficulttojoinbysuchconventionaltechniquesasarcandlaserbeamweldingprocesses,duetothesusceptibilityofthematerialstocrackinginducedbyformationofstraycrystalsduringweldsolidification.Toaddressthisproblem,applicationofanevolvingmaterialjoiningtechnique,hybridlaser‐arcwelding,tosinglecrystalsuperalloysisbeingdeveloped.Howbeit,duetoincreasedprocessvariablesandthecomplexlaser‐arcinteractioninvolved,efficientandeffectiveoptimizationofthetechniquenecessitatesnumericalsimulationmodelingofthejoiningprocess.Inthepresentwork,a3‐Dnumericalmodelthatincorporatesheattransferandliquidmetalflowwasdevelopedtosimulatetheinfluenceofvariousprocessparametersonsolidificationmicrostructuraldevelopmentduringhybridlaser‐arcweldingofsinglecrystalsuperalloy.Thedevelopment,validationandpredictionsofthe3‐Dmodelwillbepresented.Additions­SoftandDisorderedMaterials[63] CHARACTERIZINGTHERHEOLOGYOFVEGETABLESHORTENINGUSINGINDENTATIONANDFINITEELEMENTANALYSIS Gonzalez‐Gutierrez,Joamin,M.Sc.CandidateFoodScienceAdvisor:Dr.M.Scanlon

Vegetableshorteningisanimportantingredientinthefoodindustry.Rheologicalpropertiesarecriticaltoshorteningfunctionality,andtheseareusuallymeasuredbyindentation(penetrometer)tests.However,therheologicalresponseoftheseintricately‐structuredthree‐phaseparticlegelmaterialsiscomplex.Ourhypothesiswasthatbyintegratingmeasurementsofthefundamentalmaterialpropertiesofvegetableshorteningwithamechanicalmodel,theindentationresponsecouldbepredictedusingcommerciallyavailablefiniteelementanalysissoftware.Commercialvegetableshorteningwassubjecttobothlubricateduniaxialcompressionandindentationtestingusinga45degreeconicalindenter.Thefiniteelementanalysissoftwarepackage,Abaquswasusedtodeterminethegoverningparametersofanelasto‐viscous‐plasticmechanicalmodelfortheshorteningbasedonthecompressionanalyses.Themodelwasusedtopredicttheload‐displacementresponseintheindentationtests.Therheologicalbehaviorofshorteningcouldbecharacterizedby:purelylinear‐elasticatsmallstrains,strainhardeningandsofteningatintermediatestrains,andpurelyplasticatlargestrains.Rate‐dependencyeffectsweremanifestasachangeintheshapeofthestress‐straincurveratherthanjustanincreaseinstressvalueswithincreasingcrossheadspeed.Theelasto‐viscous‐plasticmodelcalibratedfromtheuniaxialcompressiondatasuccessfullypredictedtheindentationresponseofthevegetableshortening,althoughnotaswellathighloadingrates.Fromsuchanalyses,itisapparentthatindentationcanbeusedbothasasimplemechanicalqualityassurancetest,butalsotoderivefundamentalmechanicalparametersforbettercharacterizingvegetableshorteningrheologyforparticularapplications.[64] MECHANISMSOFSTABILIZINGFIBRE­ENRICHEDDAIRYPRODUCTS Repin,Nikolay,M.Sc.CandidateFoodScienceAdvisor:Dr.M.ScanlonandDr.G.FulcherAcidifieddairyproductsareoneoftheoldesttypesoffoodproducts.Unfortunatelyallofthemarelowindietaryfibre.Thus,fortificationwithdietaryfibreseemsanattractivemeansofimprovingthenutritionalprofileofproductssuchasyogurtoryogurtdrinks.However,dairyproductsenrichedwithGlucagel(acommercialproducthighinbarleybeta‐glucan)werefoundtosufferfromtexturaldefects.WhentheGlucagelconcentrationexceededacertainvalue(5g/L),dramaticphaseseparationwasobservedinsetyogurtandyogurtdrinkwhosevolumefractionofcaseinmicellesexceeded0.11.Toinvestigateinteractionsofbeta‐glucanpolymersandcaseinmicellesinthemilkpriortosettingofyogurt,mixturesofyogurtmilkandGlucagelweresystematicallystudied.DependingonthevolumefractionofcaseinmicellesandtheGlucagelconcentration,astablephaseoragelorasedimentedmaterialcouldexist.Thedrivingforceforphaseseparationwasdepletionflocculationofcaseinmicellesinthepresenceofbeta‐glucan.ThephaseseparationresponsiblefortexturaldefectsinyogurtsystemssupplementedwithhighamountsofGlucagelcanbeavoidedbythereductionofbeta‐glucanmolecularweight,aprocessthatlimitstherangeofattractionbetweenmicelles.IncubationofGlucagelwithlichenaseforvaryingtimesshiftedthephaseseparationlinestohigherconcentration.EnzymaticmanipulationofGlucagelisthusaneffective

meansofassuagingproductqualityissuesasthenaturalpropertiesofthehealthfulfibreingredientchange.