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Volume94 ,Number ,January-February1989JournalofResearchoftheNationalInstituteofStandardsandTechnology

TheStructuralCeramicsDatabase:TechnicalFoundations

Volume94 Number January-February1989R.G .Munro,F.Y.Hwang',and C.R.Hubbard'CeramicsDivisionNationalInstituteof StandardsandTechnologyGaithersburg,MD20899

Thedevelopmentofacomputerizeddatabaseonadvancedstructuralceram-icscanplayacriticalrolenosteringthewidespreadliseofceramicsinindus-tryandinadvancedtechnologies.Acomputerizeddatabasemaybehemosteffectivemeansof acceleratingtechnol-ogydevelopmentbyenablingnewmate-rialstobeincorporatedntodesignsfarmorerapidlyhanwouldhavebeenpos-siblewithraditionalinformationrans-ferprocesses.Faster,moreefficientaccesstocriticaldataisthebasisforcreatingthistechnologicaladvantage.Further,acomputerizeddatabasepro-videsthemeansforamoreconsistenttreatmentofdata,greaterqualitycon-trolandproductreliability,andm-provedcontinuityof researchanddevelopmentprograms.

Apreliminarysystemhasbeencom-pletedasphaseoneofanongoingpro-grathtoestablishtheStructuralCeramicsDatabasesystem.Thesystemisdesignedobeusedonpersonalcom-puters.Developedinamodulardesign,thepreliminarysystemisocusedonthethermalpropertiesofmonolithicceram-

ics.Theinitialmodulesconsistofmate-rialsspecification,hermalexpansion,thermalconductivity,hermaldiffusiv-ity,specificheat,hermalshockresis-tance,andabibliographyof datareferences.Queryandoutputprogramsalsohavebeendevelopedorusewiththesemodules.Thelatterprogramele-ments,alongwiththedatabasemodules,willbesubjectedoseveralstagesoftestingandrefinementinthesecondphaseofthiseffort.Thegoalof there-finementprocesswillbetheestablish-mentofthissystemasauser-friendlyprototype.Threeprimaryconsiderationsprovidetheguidelinestohesystem'sdevelop-ment:1)Theuser'sneeds;2)Thena -tureofmaterialsproperties;and(3 )Therequirementsoftheprogramminglan-guage.Thepresentreportdiscussesthemannerandationalebywhicheachoftheseconsiderationsleadstospecificfeaturesinthedesignof thesystem.Keywords:ceramics;computerizeddatabase;materialproperties;StructuralCeramicsDatabase;user-friendly.

IntroductionTechnicaladvancesinmaterialsresearchareoc-

curringt apidacenllspectsfhedevelopmentandrefinementofadvancedceram-ics.Asaresult,echnicaldataareproliferatingat'Guest Scientist from;Material Research Laboratories,Taiwan,RepublicofChina.

-Currentaddress:akRidgeNationalLaboratory,OakRidge,TN37831.

anxponentiallyncreasingate.ndustriesmayreasonablyanticipatenewtechnologicalopportuni-tiesoaccompanyheseadvancesnmaterialsre-search.However,someoftheseopportunitieswillbelostifthenewdataarenotsuccessfullycommu-nicatedtothedesignengineerswhocantransformthedatantonewrbetterproducts.heradi-tionalommunicationoutesorisseminatingtechnicaldatafrequentlyhaveslowdiffusionrates

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Volume94 ,Number ,January-February1989Journalof Researchof theNationalInstituteofStandardsandTechnologyandmaybecumbersomeouse,especiallywhendisciplinaryboundariesarecrossed.Tocapturethedataandoashiontntoanexpeditiouslyusefulform,dvancesnomputerizednformationys -temsarebeingpursuedvigorouslyinawiderangeofscientificandngineeringields1-7],ndn- volvenationalgencies8],rofessionalocieties[9],anddedicatednonprofitorganizations[10].Thepresentreportdiscussestheinitialresultsoftheef -forttheNationalnstituteftandardsndTechnologytodevelopanewdatabasesystemthatwillbeocusedncriticalmaterialropertiesofadvancedstructuralceramics.ThecurrenteffortisbeingconductednconjunctionwithheresearchprogramattheCenterforAdvancedMaterialses-tablishedathePennsylvaniaStateUniversitybytheGasResearchInstitute.

Therapidlyincreasingimportanceofcomputer-izednformationystemsseadilypparentoevenhemostcasualobserver.Thenumberofin- formationsourcesnechnicalareassenormous.Thesubjectmatterswithintheseareasareincreas-inglydiversified.Thereareasteadilyproliferatingnumberofspecializationswithineachsubjectarea.Eachpecializationeneratesechnicalerminol-ogyotnommoniththerpecializations.And,heobjectivesforobtaining,developing,rusingthedataareunlimited.

Copingwiththisabundanceanddiversityof in-formationisthefunctionofthecomputerizeddata-base.Byusingheogisticalpowerofcomputers,datacanbestored,sorted,searched,retrieved,andusednaverysmallfractionoftheimerequiredbymanualmethods.Further,datastoredinacom-puterizeddatabasemayformthebasisof atechni-calcorporatememory"ecausehevailabilityandusefulnessofthedatapersistbeyondheife-timeoftheprojecthatgeneratedhedata.Asaresult,hereisnotonlyamorerapidutilizationoftechnicaladvances,butalsoareductionofwastefulduplicationofefforts.Thispowerfulprocessingofinformationcancreateimprovedperceptionsofre-searchstrengthsandweaknessesand,hence,mayprovidemprovedmanagerialvisionforfuturee- searchplanning.

ThetructuraleramicsDatabaseSCD)ys -temsbeingdevelopedohathesecapabilitiescanbeusedtohelpindustryintakingadvantageofnewlyemergingspecializedceramics.Thisobjec-tiveaswonherentequirements.heystemmustncludecriticaldata,andhesystemmustbeeasytouse.Theformerrequirementpertainstothecontentfheatabase.heatterequirementpertainsohowhecomputerizedsystemscon-

structed.TheSCDproject,herefore,hasbothadataacquisitioncomponentandasystemdevelop-mentactivity.

Thefirstphaseof theSCDprojectwasfocusedonthedevelopmentofapreliminarysoftwaresys-tem.Theinitialemphasis,therefore,wasontechni-calconsiderations,andtheresultwasapreliminarysystemhathasullyfunctioningstorage,earch,andretrievalcapabilities.

Thefirststepoftheprojectwastoconsidertheneedsof theuser.Theuser'srequirementsformedthebasisforspecifyingheechnicalrequirementsofhenderlyingatabasemanagementystem(DBMS)hatwouldbeselectedasheprogram-minglanguage.Tofurtherguidehedevelopmentofthesystem,aspecificapplicationarea,hightem-peraturegas-fueledheatexchangers,wasselected,andhegatheringofdatawasstarted.Theseac -torswerecombinedindeterminingtheinitialstruc-tureofthedatabasesystemthatwillbediscussedin thefollowingsections.

IssuesThedevelopmentoftheCDsystemrequires

theresolutionof threesetsofissues:hedesignis- sueshatesultromonsiderationfheser'sneeds11-12],hetechnicalissuesthatresultfromtheonstraintsfherogramminganguage[13-14],andthematerialspropertiesissuesthatre-sultfromthenatureofthematerialsandthepartic-ularropertieshatreoencludednhedatabase.

TheUserInterfaceFirstandforemost,hesystemmustbeeasyouse.hesystemshouldlaceveryittledemand

uponheusernermsoftechnicalknowledgeofcomputersromputerrogramming.ncestarted,hesystemshouldguideheuserateachstepoftheinteractivesession,alwaysclearlyndi-catingheser'sptions.Neverhouldheserneedtorefertoanoperationsmanual.

Atheameime,hentelligencefhesermustberespected.Theuserofadatabasewantstoextractinformationthatusuallyhasawelldefinedscopeandcontent.Thesystemmustmaketeasyfortheusertoposequestionsohedatabasenaclearandconcisemanner,andheanswersohequestionsmustbepresentedtotheuserquicklyandin eadilynderstoodormat.hosenswersshouldalsobeexpressednunitswithappropriate

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Volume94 ,Number ,January-February1989Journalof Researchof theNationalInstituteofStandardsandTechnology

dimensionsnderminologyhatreonvenientandomfortableorheser.henswersmustalsobecomprehensivenhesensehatheuser'srangesof conditionsandquestionsareanticipated,sohathequestionscanbeasked,andhathereareatavailableonswerhem.urther,whenevertheuserwantsadditionalinformationre-gardingnypecificata,heystemhouldprovidereferencestoreadilyavailableliterature.

Toaccomplishheseeatures,hedesignofthedatabaseshouldincludethreeprimarycharacteris-tics:implescreens;menuswithlight-bars;andon-linehelp.

Inmanyrespects,whatappearsonthescreensthemmediateinkbetweenhedatabaseandheuser.heppearancefhecreen,herefore,shouldotssaultheser'sensesut,ather,shouldfocustheuser'sattentiononthecentralcon-cern.Toomuchinformationpresentedotheuseronthescreencreatesconfusionanddistraction.Tomakeascreensimple,theprogramsometimesmustbeartheresponsibilityforconsiderablepreparatorystepspriortopresentingtheprincipalscreen.Asaresult,thedesignofasimplescreenisoften,roni-cally,moredifficulthanhedesignofacompli-catedscreen.

Theus eofamenusprobablyhemostmpor-tantmeansofsimplifyinghenteractionbetweenthedatabaseandheuser.Whenmenusareused,thereisnoneedorrequirementfortheusertore-memberrogramommandshatreoore-quentlycrytic,obscure,orunclear.Theoptionsarealwaysresentedoheuserwhonlyneedsoselectnefhem.As result,herereewerentryerrors.Further,thedatabasesystemisalwaysincontroloftheprogramflow,.e.,heusercanonlyaskheatabaseooperationshattsreadytodo .If primitiveDBMScommandsareac-cesseddirectly,tspossibleoaskaprogramoexecuteperationseforellfhereparatorystepshavebeenompleted.nhisituation,heprogramanhang"rcrash".With menu-drivenystem,heesponsibilityormaintainingtheproperprogramlowrestswithhedesignofthesystem.

Menusystemsarefurtherenhancedbytheus eoflight-bars, rectangularareahatappearsonhescreenasahighlightedregion.Thelight-barhigh-lightsoneoptionandcanbemovedbytheusertoanyotheroption.Tomakeaselectionfromamongtheoptions,heusermerelymovesthelight-barto highlightthedesiredoptionandpressesthereturnkey.xactlyhesamesetofkeystrokesareusedwitheverysuchmenu.Hence,theuser'sneedtobe

familiarwithhemechanicalspectsfhekey-boardareminimized.ight-barscanalsobepro-grammedsothatapointingdevicesuchasamousecanesed,herebyntirelyliminatingkeystrokesformenuselections.Alsomportantsthefactthattheuserseeswhatthechoiceiswhenthelight-barhighlightsanoption.

Theinformationandtheoptionspresentedtotheuserofamaterialspropertydatabasemustrelatetotheechnicalontentfheatabase.onse-quently,hewordsanderminologyusedonhescreenmustbeailoredoheechnicalmaterial.Technicalerminologysarelytandardizedacrossalldisciplines.Therefore,tsessentialhatonlinehelpbeavailableoheuseratanyimeoexplainheptionsndheerminology,ndoprovidereferencesoheiteraturewherenn- depthiscussionnheubjectmatteranefound.Onlinehelpprovidesinformationtotheuserimmediately,whenitmeansthemosttotheuser.MaterialsPropertyIssues

Theesignfaatabaseecessarilyequiresconsiderationof theinformationtobecontainedin theatabase.Datan atabaseccursnourtypes:umeric(numbers),character(words),logi-cal(trueorfalse),anddate(month,day,andyear).Beforethedatabasecanbeprescribed,hetypeofdatathatitistocontainmustbeknown.Thespeci-ficationofwhatspecificinformationisneededforamaterialspropertydatabaseses sobvioushantmightseematfirstthought.Forexample,considerwhatsrequiredodentifyaparticularstructuralceramicmaterial.Whatcharacteristicsuniquelyde-finehematerial?Conversely,canhematerialbegroupedwithothermaterialsaspartofamoregen-eralclass?

Itswidelyrecognizedhathenameoface-ramicmaterialdoesnotprovideanadequatede -scriptionfhematerial.orexample,herearemanyormsofsiliconnitride.Allsiliconnitrideshaveheamerimaryhemicalormula,i3N4,butthesinteringaids,impuritycomponents,poros-ity,andmicrostructurearedifferent.Thisquestionofidentifyingaceramicmaterialsbeingnvesti-gatedurrentlyyheASTMommittee-49,ComputerizationofMaterialPropertyData.Theirdeliberationsindicatehatatleast10categoriesofsupportinginformation,alsocalledmetadata,able1 ,aredesirableforthespecificationofanadvancedmaterial15].hesedescriptorsonlydentifyhematerialndootprovideanyfhematerialproperties.

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Volume94 ,Number ,January-February1989JournalofResearchof theNationalInstituteofStandardsandTechnologyTable .reliminaryguidelinesromASTMCommitteeE-49regardinghecategoriesofnformationneededodescribeamaterialordatabasepurposes

MaterialClassSpecificMaterialwithinaClassMaterialDesignationMaterialConditionMaterialSpecificationProducerorSourceofMaterialProducerLotNumberand/orAssignedReferenceNumberProductFormMaterialCompositionFabricationHistory

Eachmaterialropertyoencludednhedatabaselsomusteivenarefullyelectedspecificationata.Whatsheroperty?Whatmethodwasusedomeasuret?Arehedataofreasonablequality?

Therangeof propertiesthatshouldbeincludedinhedatabasedependsonheapplicationorheintendedus eofthedatabase.Ageneraldatabasethatsnotocusednnyarticularapplicationwouldneedtoincludefartoomanypropertiesthanwouldbepractical.Ratherhanconstructadata-basethatisentirelycomprehensive,itispreferablethatthedatabasebedevelopedforawellfocusedapplicationorhichheriticalataaneclearlydetermined.

Foranygivenproperty,animportantissueper-tainingoheusefulnessofthedatashowmuchsupportingdetailhouldbevailableoescribehowheropertyaluewasetermined.Whatdepthfnformationsequiredoncerninghemethodused,theconditionsof theexperiments,orthestatisticalreatmentshatmayhavebeenap -pliedtothedata?Thesequestionsareencounteredwheneverdataarereportedinthetechnicallitera-ture.echnicalapersresuallyequiredoprovideinsomemanneracompletedescriptionofal lxperimentalpparatus,xperimentalroce-dures,anddataanalysis.Adatabaseisnotintended,andshouldnotbeexpected,oreplaceatechnicalpaper.However,tmayemportantonowwhatexperimentalechniqueswereusedtoevalu-ateheproperty.Differentmethodsmaysubjectthematerialtodifferentconditions,andhence,theresultsfromonetechniquemaybemoreappropri-atetotheuser'sapplicationthanothertechniques.Toaccommodateheneedobelear,uccinct,andcompletewithrespecttopropertydataandits determination, ibliographyfechnicalefer-encesshouldbemaintainedaspartofthemetadatausedtodescribeandrecordmaterialproperties.

Thefinalconcernregardingthedataisthequal-ityofhevaluesrecordednhedatabase.omeassessmentofthequalityofthedata,tsaccuracyorreliabilitymustbeprovidedwiththevaluethatisrecordedinthedatabase.If therearelimitationsonhevalidityofthevalue,heuserneedsobeforewarnedfheimitations.hedesignofhedatabase,herefore,shouldincludemetadatafieldsinwhichthequalityandlimitationsof thedatacanbenoted.

ConstraintsoftheProgrammingEnvironmentTheprogrammingenvironmentforthedevelop-

mentofadatabaseismostconvenientlyandwiselytakentobeacommerciallyavailabledatabaseman-agementsystem(DBMS).ADBMSisessentiallyalanguagethatcanbeusedtotellthecomputerhowtotorendetrieveata.ommercialDBMSpackagescontainmanyhighlyrefinedfeaturesthatgreatlyfacilitatehecreationofadatabasearchi-tectureandprovideheessentialmeansosearchfornformationstoredwithinheresultingstruc-ture.Thesefeatures,whilesophisticatedanddesir-able,maylsoeiewedsonstraintsnhedatabasedesign.Thus,tsmportantodentifytheechnicalfeatureshatarenecessaryosecurecompatibilitywiththedatathataretobeincludedinthedatabaseandtoensurethefulfillmentoftherequirementsof theuser.

TheSCDmustconsistofmanymaterialproper-tiesndharacteristics,ncludinghematerialsspecification,hemicalomposition,icrostrui:;- ture,mechanicalproperties,andthermalcharacter-istics.achiecefnformationhatsoeincludedinthedatabasemustbeallotedadistinctamountfspacewherehenformationanestored.Inthesimpleststructureofadatabase,hepieces,calledfields,areconcatenatedtoformasin-glecollectionofinformation,calledarecord.

Field Field2 Field3 Field4 Field5 Field6asllustratednhediagram.nhisexample,ix fieldsofdifferentsizesarejoinedogetherononelineoormneecord.hecompletedatabasemayhenbevisualizedasacollectionofseveralsuchrecords,oneperline,witheachfieldalignedtoormacolumn.Acollectionofthreerecordswouldlooklikethefollowingmatrix:

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(Field ) (Field2) (Field3) (Field4) (Field5) (Field6) ( 1 , 1 ) ( 1 , 2 ) ( 1 , 3 ) ( 1 , 4 ) 1 , 5 ) ( 1 , 6 )( 2 , 1 ) ( 2 , 2 ) ( 2 , 3 ) 2 , 4 ) ( 2 , 5 ) ( 2 , 6 )( 3 , 1 ) ( 3 , 2 ) ( 3 , 3 ) 3 , 4 ) ( 3 , 5 ) ( 3 , 6 )

Inprinciple,hisrecordstructurecanbeusedforanydatabase.Inpractice,however,hisstructurecanbesomewhatawkwardandinconvenient.

Tollustratehispoint,considerasimpledata-basethatcontainsonlyselectedthermalpropertiesofmaterialsasafunctionoftemperature.Forthepurpose ofdiscussion,assumethatthefieldsforthishypotheticaldatabasearerestrictedtothenameofthematerial,thetemperature,hethermalconduc-tivity,ndhehermalshockresistance.upposealsohatesultsorluminaavebeenbtainedfromapublishedsourcethatreportedthethermalconductivityatthreetemperatures.Then,thedata-basewithonlythisdatawouldbe :(Material (Temperature) (Conductivity) (Shock

Name) esistance)Alumina 2 0 2 9Alumina 5 0 0 1 2Alumina 1 0 0 0 9

Thedatabasehashreerecordscorrespondingothehreeemperaturesatwhichhehermalcon-ductivitywasdetermined.ThefieldcontainingtheMaterialNamehashesamenformationneachrecord.Thisredundancyofinformationsypicalofmuchofthesupportingnformationhatsre-quiredomakeheatabaseseful.Manymorefieldswithsuchmetadatawouldbenecessaryocompletehespecificationofagooddatabaseonthermalconductivity,ncludingheunitsofem-peratureandhermalconductivity,detailednfor-mationonhecompositionandmicrostructureofthematerialandheprocessingechniqueusedomakehematerial,anddetailsabouthemeasure-mentmethod.Theproliferationofsuchieldscanrapidlyleadtoahighdegreeofredundantinforma-tionnhedatabase.Inheexample,hefieldforShockResistancesnotonlyredundant,butalsosuperfluoussincenovaluesforthatpropertyweregiveninthereferencedreport.

Redundantandsuperfluousdataarewastefuloflimitedstoragespace,reducethespeedwithwhichtheinformationcanbeprocessed,andincreasethe

potentialforerrorsintheentryof theinformationintothedatabase.Toavoidhissituation,adiffer-enttypeofdatabasestructureisneeded.Insteadoflinkingallheieldsogetherntoasinglerecord,theieldsanbedividedntoogicalubgroups.Eitherahierarchialorarelationaldatabasestruc-turecanaccomplishthisorganization.

Hierarchialdatabasesachievealogicalorganiza-tionandspaceefficiencybycreatingareestruc-ture.achewomponentoheatabasebecomesanewbranchinthetree.Ifacomponentisnotused,hatbranchdoesnotneedobecre-ated.Thus,thehierarchialsystemdoesnotrequireanywastedspace.However,maintenanceorrevi-sionof thetreestructurecanbecumbersome,andnavigatingthetreefromonerecordtoanothercanbeawkward.

Relationalatabasesrovide moreesirablestructureforscientificandengineeringapplicationsthatmayanticipateaneedforrevisionasthedisci-plineprogresses.Tollustratehispoint,considertherecedingxample.heriginalatabasecouldbedividedntohreecomponentdatabases,oneeachformaterialsspecification,hermalcon-ductivity,andhermalshockresistance.Inarela-tionaldatabasesystem,eachofthesecomponentscanbemaintainedndependently,providedhatauniquerelationbetweenhecomponentssspeci-fiedandpreserved.Thisrelationshipcanbeestab-lished,forexample,byaddinganewfield,calledakey,hatdentifieshesourceofthedataneachcomponent.nhexample,hehreeubgroupdatabasescouldbedefinedasfollows:

ields

(ID) (Name)

ubgroup-

Materials:

ThermalConductivity: (ID) (Temperature) (Conductivity)

0 0 0 1 Alumina

0001 2 0 2 90 0 0 1 5 0 0 1 20 0 0 1 1 0 0 0 9

ShockResistance: (ID) (Temperature) (Resistance)

Thereaterfficiencyfherelationalatabasestructureisreadilyapparenteveninthisrestrictedexample.TheadditionoftheIDieldssufficienttomakeheelationshipetweenheubgroups

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Volume94 ,Number ,January-February1989Journalof ResearchoftheNationalInstituteofStandardsandTechnology

clearandunambiguous.henewtructurecom-pletelyeliminatesthepreviouslyredundantandsu-perfluousdata.Foramaterialspropertydatabase,afullydevelopedsubgroupmightcontainasmanyas 50ields.Hence,herelationaldatabasestructuremaybeconsideredhepreferredstructureforsci-entificandengineeringdatabases.

Inheexample,tmaybeoted,urther,hatthreerecordswererequiredtorecordhethermalconductivityatthreetemperatures,eventhoughal lthreeesultswerebtainedromneeference.Logically,itwouldbeeasiertosearchandretrievethisinformationifal lthevalueswerecontainedin oneecord.AdvancedDBMSackagesrovidethisatastructurenheormofmultipleentryassociatedields.Inamultipleentryield,avari-ablenumberofdifferentvaluescanbeentered.As- sociatedieldsaremultipleentryieldsforwhichtheresaone-to-onecorrespondencebetweenheassociatedentries.Forexample,iftemperatureandconductivityareassociatedields,henheTher-malConductivitysubgroupdescribedabovewouldbecome:ThermalConductivity:ID) (Temperature) (Conductivity)

0001 20 ,500,1000 29 , 2,9Thefirstentrynheemperatureield,20 ,corre-spondsoheirstentrynheconductivityield,29 .Associatedieldscapturetheentiresetofrele-vantdatainthesinglerecord,herebymakingthesearchandretrievaloperationsmoreefficientandfaster.Theentireexampledatabase,recastasare-lationalatabasewithssociated,multiplentryfields,isreducedtoonlythefollowing:

ubgroupMaterials; (ID)

Fields

(Name)0001 Alumina

ThermalConductivity: (ID) (Temperature) (Conductivity)0001 20 ,500,1000 29 ,2,9

ShockResistance: (ID) (Temperature) (Resistance)

Mostmaterialspropertyinformationoccurswithparametricdependenciesandwithmanymetadatafields.Hence,associatedmultipleentryieldsnarelationaldatabasearenaturalanddesirablerefine-

ments ofthedatabasearchitectureforscientificandengineeringapplications.

Nexttothespecificationof theunderlyingdata-basetructure,hemostmportantonsiderationfortheprogrammingenvironmentisheabilitytosearchhedatabasefornformation.ndeed,tsthisstabilitythatmakesdatabasesusefulandpow-erful.Asaresult,hesearchandretrievalfeaturesarethehighlightsofmanyof theadvancedDBMSpackagesavailablecommercially.Inmakingcom-parisonsofsearchndretrievalapabilities,tsimportantoecognizehatmostearchesrespecifiednermsfheupportingetadataratherhanhepropertyitself.Manyofthemeta-datafieldsaretextualincharacter,.e.,collectionsofwords.Toindwhattheuserhasspecified,heDBMSmayneedtosearchwithinafieldtofindtheuser'swordsmbeddedwithinheield.NotllDBMSackagespermithisypeofsearch.ormaterialsropertyatabases,earchingwithinfieldmayessentialorcharacteristicsuchschemicalcomposition,microstructure,orprocess-ingconditions.Asummaryofthegeneralcharac-teristicshatmayeasonablyexpectedfDBMSforscientificandengineeringapplicationsisgivenintable2.Table2.Essentialrequirementsforadatabasemanagementsys-temDBMS)appliedoscientificandengineeringnformationsystems

RelationaldatabasestructureVariablelengthieldsLargefieldengths,nkilobyterangeMultipleentryieldsAssociatedieldsLargenumberoffieldsperrecordLargetotalrecord izes,nkilobyteangeVerylargemaximumnumberofrecordsHighefficiencyndexingConcurrentindexingMultipleieldkeysforindexingSearchonanyieldSearchwithinaieldLogicallyconcatenatedsearchesonseveralieldsCompatibilitywithothercomputerlanguagesCompiledorruntimecodes

StructuralCeramicsDatabaseThedevelopmentoftheSCDsystemhasbeen

structuredinalogicalsequenceofsteps.Initially,aparticularpplicationwaselectedorovidedefinitefocusforthechoiceof propertiestobein-cludednhedatabase.Theparticularapplication

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wasselectedafterconductingasurveyoftheactiv-itiesof theproject'sfoundingsponsor,theGasRe-searchnstituteGRI)16].RIontractorsindicatedthattailoringthesystemforusewithheatexchangerandrecuperatordesignwouldbeespe-ciallyvaluabletotheminboththeshort-termandtheong-term.FurtherdiscussionswithGRIcon-tractorsandotherresearchandindustrialcontactsproduced istfcriticalroperties,.e.,hosepropertieshatreneededorheesignffortsandforwhichcurrentinformationisofteninacces-sible,cumbersomeoind,and/oressentialohedesign.Withafocusedapplicationandasamplingoftheypicaldatatobencludednthedatabase,theeneralechnicalpecificationswereormu-lated.Thelatterspecificationswerecoupledtothesystemneeds,as seenfromtheuser'spointofview,todeterminetheoverallrequirementsforthebasicdatabasemanagementsystem(DBMS),assumma-rizednable.asednhoseequirements,commerciallyavailableDBMSwasselected.

Theystemoftwareesignffortashenaimedatdevelopingafullyfunctioningprototypesystem.Theconstructionoftheprototypewasbe -gunusingamodulardesignconsistingofgeneralmoduleshatmaybeusedforanyargetapplica-tion,ndailoredmoduleshatertainnlyospecificmaterialproperties.

Themodulardesignprovidesconsiderableflexi-bilityndllowsheystemoexpandedradaptedtodiverseapplications.Thisdesignisalsobeingexploitednapragmaticway.Itsperhapswellknownthatitismucheasiertodevelopapro-grammer'sworkingsystemhanitsodevelopaworkinguser-friendlysystem.Itmayalsobereadilyunderstoodhatertainatantryndeviewmodulesarenecessarybeforedatacanbeenteredintohesystemandbeverified.Consequently,omaximizehefficiencyfheystemevelop-ment,haseoneofhisprojectwasdirectedo-wardsheevelopmentfhosemoduleshatwouldprovideaworking,reliminarysystemas soonaspossible.heusernterfacemodulesarescheduledobedevelopednthesecondphaseoftheproject.

Thepreliminarysystemofthephaseoneeffortisnowcomplete.Thepreliminarysystemconsistsofmodulesformaterialsspecification,hermalexpan-sion,hermalonductivity,hermaliffusivity,specificheat,thermalshockresistance,abibliogra-phyofdatareferences,queries,andoutput.ur-rently,heueryndutputmodulesreathergeneral,fordevelopmentpurposes,andneedtobe

streamlinedbeforebeingusednheprototypeofphasetwo.Theothermodulesarereadyfortestingintheircurrentforms.

Tables3-9summarizethecontentsofthecurrentprimarynformationmodules.oromeields,suchasMaterialClass,heentriesarerestrictedtoasmall,inite,closedet .Thepossibleentriesforthosefieldsarealsoshowninthetables.Table3.Alistingoftheinformationfieldscontainedinthema- terialsspecificationmodule.Whereonlyixedntriesareal- lowed,healternativesareistedbelowthefieldtopicMaterialclass:

MonolithicceramicStructureclass:

Polycrystalline,Singlecrystal,Graphitic,AmorphousChemicalclass:

Carbide,Nitride,OxideChemicalnameChemicalAbstractServiceNumberChemicalormulaSourceof thematerialManufacturer'sdesignationforthematerialManufacturer'slotnumberProductdateStandarddesignspecificationcodeOrganizationsettingstandardspecificationSupplementaryinformationregardingspecificationFabricationprocess:

Slipcasting.Tapecasting.Sinteringfiring).Extension,Mechanicalhrowing,Diepressing,Isostaticpressing.Injectionmolding.Hotpressing,Glassceramicsroute,Glazing,Plasmaspray.Chemicalvapordeposition.Crushedground

Fabricationorm;Plate,Bar,Rod,Wire,Tube,Thickilm.Thinfilm.Powder

FabricationhistorySpecimenstate:Virgin,ModifiedDescriptionofspecimenmodificationLocationofthespecimenromwithintheabricationformElementalcompositionofthematerialWeightpercentsoftheelementalcomponentsStandarddeviationsofweightpercentsofelemental

componentsPhasecompositionofthematerialWeightpercentsofthephasecomponentsStandarddeviationsofweightpercentsofthephase

componentsMeanvalueofthebulkdensityofthematerialUnitofdensity:/cm',kg/m'TheoreticdensityGrainsizeUnitofgrainize:am,mm,m KnownorintendedapplicationsofthismaterialSupplementarynotes

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Volume94 ,Number,January-February1989JournalofResearchoftheNationalnstituteof StandardsandTechnology

Table4,Alistingoftheinformationfieldscontainedinthether-malexpansionmodule.Whereonlyixedentriesareallowed,thealternativesarelistedbelowtheieldopicMeasurementmethod:

Push-roddilatometer,Twinele-microscope.Interferometer,Singlecrystalx-raydiffraction.Powderx-raydiffraction.Neutrondiffraction.Highspeedpulsedheating,Volumetricdilatometry,ASTMC372(Dilatometry),ASTME289(Interferometry),ASTME831Thermodilatometry),Other

Samplepreparation/pretreatmentMeasurementnotesQualityCautionsUnitoftemperature:C,F,KUnitofthermalexpansioncoefficient: 10"KThermalexpansioncoefficientsattemperature:

TemperatureBulkaveragevalueValuealonga-axisValuealong6-axisValuealongc-axis

Polynomialrepresentationofprincipalaxialcoefficientsa(i,i):Temperaturerangefroma(l>1)=.a(2,2)=,a(3,3)=.

_+._ + _

,(r/iooo)-i-. _ (r/iooo)-i-. .(r/iooo)-)-_

.(r/iooo)-

.(r/iooo)-

.(7-/1000)^

Table5.Alistingoftheinformationfields containedinthether-malconductivitymodule.Whereonlyfixedentriesareallowed,thealternativesarelistedbelowthefieldopicMeasurementMethod:

Longitudinalheatlow,Forbes'bar.Radialheatflow.Directelectricalheating.Thermoelectric,Thermalcomparator,Periodicheatflow.Transientheatflow,ASTMC201Comparative),Other

SamplePreparation/PretreatmentMeasurementNotesQualityCautionsUnitoftemperature:C,F,KUnitofthermalconductivity:Wm'KTemperatureThermalconductivity

Table6.Alistingoftheinformationfieldscontainedinthether-maldiffusivitymodule.Whereonlyixedentriesareallowed,thealternativesarelistedbelowthefieldtopicMeasurementMethod:

Center-heatedongbar,End-heatedlongbar,Movingheatsource.Smallareacontact.Thermoelectriceffect,Semi-infiniteplate.Radialheatlow.Highntensityarc.Flashheating,Electricallyheatedod.Angstrom'smethod.ModifiedAngstrom'smethod.Temperaturewavevelocity.Temperaturewaveamplitude-decrement.Phaselag,Radialwave,ASTMC351InsulatingMaterials),ASTMC714(ThermalPulse),Other

SamplePreparation/PretreatmentMeasurementNotesQualityCautionsUnitof temperature:C,F,KUnitofthermaldiffusivity:m'sTemperatureThermalDiffusivity

Table.Aistingofhenformationieldscontainednhespecificheatmodule.Whereonlyfixedentriesareallowed,thealternativesarelistedbelowheieldopicMeasurementMethod:

Nernst-typeadiabaticvacuumcalorimeter.Modifiedadiabaticcalorimeter.Dropcecalorimeter.Dropisothermalwatercalorimeter,Dropcopperblockcalorimeter.Pulseheating,Comparativemethod,ASTMC351InsulatingMaterials),Other

SamplePreparation/PretreatmentMeasurementNotesQualityCautionsUnitoftemperature:C,F,KUnitofspecificheat:kg KTemperatureSpecificheat

Table8.Alistingofthe information fieldscontainedinthe ther-malshockmodule.Whereonlyixedentriesareallowed,healternativesarelistedbelowheieldopicMeasurementMethod:

WaterQuench/InternalFriction,OtherSamplePreparation/PretreatmentMeasurementNotesQualityCautionsUnitoftemperature:C,F,KCriticalquenchemperaturedifference

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Table9.Alistingoftheinformationfieldscontainedinthebib-liographymodule.Whereonlyixedentriesareallowed,healternativesarelistedbelowhefieldopicNamesof authorsTotalnumberofauthorsCountryofauthorsTitleofpaper/report/articleTypeofpublication:

Journal,Book,Generalreport.Contractreport,Conference,Dissertation/Thesis,Patent,Magnetictape.Private,Other

NameofpublicationmediumNamesof editorsofthepublicationmediumLanguageofpublicationChapternumberVolumenumberIssuenumberPagenumbersPublicationdatePublisherSponsorSiteofconference,meeting,universitygrantingdegree,

orothersitePatentnumberPatentcountryInitialsourceof abstractcitationChemicalAbstractServiceabstractnumberInternationalStandardSerialNumberNumberofmaterialsdiscussedNamesofmaterialsSynonymsformaterialsChemicalAbstractRegistrynumberPhysicalpropertiesdiscussed:

LatticeparameterChemicalpropertiesdiscussed:

Corrosion,Corrosionproducts.Corrosionate,Oxidation,Chemicalreactivity,Stability

Thermalpropertiesdiscussed:Thermalexpansion,Thermalconductivity,Thermaldiffusivity.Specificheat.Thermalshock.Thermalemissivity

Mechanicalpropertiesdiscussed:Elasticmodulus.Elasticconstants.Young'smodulus(E),Shearmodulus,Poisson'sratio.Bulkmodulus.Compressibility,Strength,Tensilestrength.Flexurestrength.Bendstrength.Fracturestrength,Rupturestrength.Stress-strain,Fractureenergy.Fracturetoughness.Toughness,R-curve,Criticalstressintensityactor.Crackgrowth,Creep,Creeprupture,Fatigue,Cyclicfatigue

ThenitialmaterialspecificationmoduleasbeenconstructedinaccordancewiththeguidelinesevolvingfromthedeliberationsofASTMCommit-tee-49,omputerizationfMaterialropertyData.Theguidelines,summarizedntable ,havebeenmplementedbydividingherequirednfor-mationinto32fields.Inbrief,hesefieldsdescribewhatthematerialiscalled,howandwhereitwasmade,andwhatphysicalandchemicalcharacteri-zationinformationhasbeenrecorded.

Theaterialsropertyatabasesreon-structedwithhesetsofinformationieldsnten-tionallykeptmall.heuser'sirstprioritysoknowthevalueofapropertyunderaspecifedcon-dition.Ingeneral,eachofthemeasurementmeth-odshascertainmeasurementconditionsassociatedwitht.hus,dentifyinghemethodffectivelyidentifiesheconditions.fcompleteetailsfaparticularmeasurementareneeded,heusermayconsultheiteraturereferencehatsncludednthebibliographicdatabase.Further,ahelpfunctionprovidesgeneralreferencesnwhichdescriptionsofallherelatedmeasurementechniquesmaybefound.

Discussion Fromhepointofviewofheuser,hebasicfunctionofthedatabasesohelpheuserobtain

information.Todohis,hedatabasesystemmusthaveaflexible,butuserfriendly,querycapability.TheessenceofthequerysystemnheSCDsl-lustratedinthefollowingflowchart:

StartOld Old,New,orExit? Exit System

New

RecallSubject,TopicandConditionSpecifications

SelectSubjectArea

SelectTopicwithinSubjectAreaSpecifyConditions

Yes SaveSubject,Topic,andConditions?Save No

SelectInformationtobeRetrievedandReported

ReportInformationYesMorenformation?

No YesOtherConditions?No

OtherTopics?No

YesNo

OtherSubjects? Ye s

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Volume94 ,Number ,January-February1989Journalof ResearchoftheNationalInstituteofStandardsandTechnology

Anyqueryessionmaybesavedforfutureuse.Therefore,athebeginningofanewession,heusersgivenheopportunityorecallapreviousqueryorostartanewone.AnewnvestigationbeginswithheselectionofthecentralsubjectonwhichhesearchoftheSCDwillbebased.Thesubjectcouldbeamaterial,aproperty,orabiblio-graphiceference.orxample,oxaminehepropertiesofasiliconnitride,thesubjectwouldbeceramicmaterialsandheopicwouldbesiliconnitride.urtherpecifications,uchsinteringaids,phasecomposition,oramaximumvalueforthethermalexpansioncoefficient,couldbe madein theSpecifyConditionsstep.Whentheuserissatis- fiedwithheconstructedquery,hequerycondi-tionsmaybesavedforfuturereference.

TheCDystemuseshequeryconditionsoselectfromheentiredatabaseonlyhesubsetofrecordshatulfillheser'sequirements.heusermayhenchooseoexamineanypartoftheinformationnheubset.orxample,avingspecifiedsiliconnitridewithMgOas asinteringaidand inearhermalxpansionoefficientotgreaterhan3.5 X 10"' 'K~',heusercouldreadilydeterminethevariationofthethermalshockresis-tancewithrespectofabricationprocess.Thelat-ternformationwouldebtainedypecifyingthathehermalshockresistanceandheabrica-tionrocessencludednhestftemse-portedtotheuser.

TheSCDqueryprogramismorepowerfulthanthesimplifiedflowchartreveals.Indeed,hepro-gramcurrentlyistoopowerfultobeuserfriendly.Withinhespecificationsofconditions,tispossi-bleoonducteveralndependentueriesndthencombinehemnto singlecomplexquery.However,complexqueriesrequiretheusertohaveaconsiderableknowledgeabouthestructureandcontentoftheieldsnhevariousdatabases.Anobjectiveoftheusernterfacemodulewillbeoharnessthepowerofthequeryprogramsothattheuseranindreciselyhenformationhatswanted,withoutnn-depthnowledgefheSCDsystem.Conclusion

ThetructuraleramicsDatabaseSCD)ys -temsbeingdevelopedasameansofacceleratingadvancesnceramics-basedechnology.heirstphaseoftheongoingSCDprogramhasresultedin apreliminarysystemforusewithpersonalcomput-ers.Thisphase-onesystemsfocusedonheher-

malropertiesfonolithiceramics.hemodulardesignof thesystempermitsindependentmodulesformaterialsspecification,thermalexpan-sion,hermalonductivity,hermaliffusivity,specificheat,thermalshockresistance,andabibli-ographyofdatareferences.Accessingtheinforma-tioncontainedinthesemodulesisaccomplishedbyqueryandoutputprogramelements.

Thedesignofthesystemhasbeenbasedonan analysisofthreeprimaryconsiderationsrelatingtotheuser,thematerialsproperties,andtheprogram-minganguage.achconsiderationmposeson-straintsnheesignfheystem.heser'sinterestistheprincipaldeterminantofthecontentofthedatabaseandhedesignofthemannerandstylewithwhichthesysteminteractswiththeuser.Theprogramminglanguagedeterminesthetechni-calimitationsonhowhedataareactuallyman-aged.hematerialsropertieseterminehatprovisionsarenecessarytoensurethatthecriticalinformationisadequatelyandaccuratelycommuni-catedtotheuser.Thelatterprovisionsimposecon-straints,orexample,nataalidationoutinesfordataentryandonquerystructuresfordatare-trieval.

ThesuccessoftheSCDsystemwillrestfirstonitsemphasisonuser-friendlinessandsecondonits contentfcriticallymportantata.heonve-nience,speed,andefficiencyoftheaccessohedatawillnableevelopmentsnesearchobetransferredondustrialpplicationsarorerapidlythancouldbeexpectedwiththetraditionaltechnologytransferprocesses.Acknowledgment

TheauthorswishtothankthegeneroussupportoftheGasResearchInstituteasafoundingsponsorinheNISTrogramoevelophetructuralCeramicsDatabasesystem.Numeroushelpfuldis-cussionswith..Messinareratefullyc-knowledged.

References[1 ]Grattidge,W.,Westbrook,J.,Northrup,C,andRumble,

J.,Materialsnformationorciencendechnology(MIST)ProjectOverview,Natl.Bur.Stand.U.S.)Spec.Publ.72 6(1986) .

[2]oerstra,M.L.,EngineeringDatabases(Elsevier,Amster-dam1985).

[3]umble,J.,andSibley,L. ,TowardsaTribologyInforma-tionystem,atl.ur .tand.U.S.)pec.ubl.37 (1987) .

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[4]Dabrowski,..,andJefferson,D.K.,AKnowledge-BasedystemorhysicalDatabaseDesign,Natl.ur .Stand.U.S.)Spec.Publ.500-1511988) .

[5]ahanmir,.,su ,. M.,ndMunro,..,ACTIS:TowardsaComprehensiveTribologyDatabase,Proc.oftheASTMConfonComputerizationandNetworkingofMaterialPropertyDatabases(ASTM,Philadelphia1987).

[6 ]Kaufman,J.G.,StandardsActivitiesofASTMCommitteeE-49,FirstnternationalSymposiumonComputerizationandNetworkingofMaterialsPropertyDatabases(ASTM,Philadelphia1987).

[7]Onkik,H.M.,andMessina,.G.,reatingaMaterialsDatabaseBuilderandProducingPublicationsorCeramicPhaseDiagrams,Proc.oftheASTMConfonComputeri-zationndNetworkingfMaterialropertyDatabases(ASTM,Philadelphia1987).

[8 ]NationalnstituteofStandardsandTechnology,Depart-mentofEnergy,DepartmentofDefense,NationalScienceFoundation,andElectricPowerResearchInstituteareex -amples.

[9]American Society forestingndMaterials (ASTM),AmericanCeramicSociety,AmericanChemicalSociety,andAmericanSocietyofMechanicalEngineersareexam-ples.

[10]NationalMaterialsPropertyDataNetwork,nc.sanex -ample.

[11]urlingam,A.,MatchingaDBMSoUserNeeds,Mini-MicroSystems,Oct.1981) .

[12]ones,P.F.,FourPrinciplesofMan-ComputerDialogue,ComputerAidedDesign10 , 971978).

[13]tamen,J,,andostello,W.,valuatingDatabaseLan-guages,Datamation,May(1981) .

[14]Dieckman,E.M.,ThreeRelationalDBMS,Datamation,Sept.1981) .

[15]Kaufman,..,tandardsoromputerizedMaterialPropertyDataourcesndntelligentKnowledgeys-temsnManagingngineeringata:heompetitiveEdge,R.E.Fulton,ed .AmericanSocietyofMechanicalEngineers,NewYork1987).

[16]Hubbard,C.R.,Dapkunas,S.J.,Munro,R.G.,andHsu,S..,dvancederamics:AriticalssessmentfDatabaseNeedsorheNaturalGasIndustry,Natl.Bur.Stand.U.S.)NBSIR88-3706(1988) .

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