Unit-4-Method(教材答案)

Unit4MethodV.Exercises1.Sample:ConsideradiskasshowninFig.1.Thediskiscoupledwithapinwithaninitialradialclearance.Anapproximationisintroducedinordertosimplifythegeometryfortheanalyticalandnumericalsolutions.Figure2highlightshowtodecomposethevectorthatindicatesthepositionofthemass.Thecentrifugalforcesmaybewrittenasthesumofthetwocomponentsxandy.Forsimplicity,hereafterthepinisassumedasbeingrigidandthediskasdeformable.2.Sample:Firstly,thelogsareplacedintheshredder.Thentheyarecutintosmallchipswhicharemixedwithwaterandacid.Afterthat,theyareheatedandcrushedtoaheavypulpwhichiscleaned.Itisalsochemicallybleachedtowhitenit.Later,itispassedthroughrollerstoflattenit.Thensheetsofwetpaperareproduced.Finally,thewaterisremovedfromthesheetswhicharepressed,driedandrefineduntilthefinishedpaperisproduced.3.Sample:Twoexperimentswerecarriedoutusingdifferentcombinationsofseasoningandvaryingcookingtemperatures.A4.5kgfrozenorganicchickenwaspurchasedfromBuyriteSupermarket.Buyriteonlysellsgrade“A”chickensapprovedbytheOrganicFarmersAssociation,thusensuringboththehomogeneityofthesampleandthequalityoftheproduct.SeasoningwereobtainedfromSeasonIncUKandwereusedassupplied.AccordingtothemethoddescribedbyHanksetal.(1998),thechickenwasfirstimmersedinfreshlyboiledwatercooledtoatemperatureof20°Candwassubsequentlyrinsedthoroughlyinasaltsolutionsoastoreducethelevelofbacteriaonthesurfaceofthechicken.Inordertoobtaintwosamplesofequalsizeandweightfortesting,thechickenwasfirstskinnedusingastandardBS1709Skin-o-matic;thefleshwasthenremovedfromthebonewitha4cmsteelSabatierknife,afterwhichitwascutinto3cm-cubes,eachweighing100g.Twoofthecubesthusobtainedwererandomlyselectedfortesting.ThecubesweredriedindividuallyinaPhillipsR2D2Dehydratorfor10minutes.Immediatelyafterremovingeachcubefromthedehydratoritwascoatedwiththeselectedseasoningmixtureandlefttostandonaglassplatefor30minutesatroomtemperature(16°C)inordertoenhanceabsorptionoftheseasoningpriortoheating.Seasoningquantitiesweremeasuredusedstandarddomestickitchenscalesandwerethereforeonlyapproximate.Eachcubewasthenplacedonanovenproofdishandtransferredtoapre-heatedPanasonicModel33KYstandardelectricfan-assistedovenat150°Cfor10minutes.Theproductwasremovedfromtheovenandallowedtocometoequilibrium,afterwhichthecubeswereassessedaccordingtotheTTStestdevelopedbyDundee(Dundee,1997).