简介：AlatticeBoltzmannnumericalmodelingmethodwasdevelopedtopredictskinconcentrationaftertopicalapplicationofadrugontheskin.ThemethodisbasedonD2Q9latticespacesassociatedwiththeBhatnagar-Gross-Krook(BGK)collisiontermtosolvetheconvection-diffusionequation(CDE).Asimulationwascarriedoutindifferentrangesofthevalueofbound,whichisrelatedtoskincapillaryclearanceandthevolumeofdiffusionduringapercutaneousabsorptionprocess.Whenatypicaldrugisusedontheskin,thevalueofcorrespondstotheamountofdrugabsorbedbythebloodandtheabsorptionofthedrugaddedtotheskin.Theeffectofwasstudiedforwhentheregionofskincontactisalinesegmentontheskinsurface.

简介：Acombustionmodelofalarge-scalesupercriticalcirculatingfluidizedbed(CFB)boilerwasdevelopedforcomprehensivecomputational-fluid-dynamicsanalysis.Themodelincorporatesgas-solidhydrodynamics,coalcombustion,heattransferonheatexchangesurfacesinthefurnace,andheattransferbetweenfumaceandworkingmediumintheheattransfertubes.Insimulatingthedenseanddilutephasesinthefumace,thegas-solidhydrodynamicsisbasedontheEuler-Eulermodelandenergy-minimizationmultiscaledragmodel.Coalcombustionentailsevaporation,devolatilization,charcombustion,gashomogeneousreaction,andpollutantemission.Thecoefficientofheattransferbetweengas-solidandthewaterwallisestimatedusingtheclusterrenewalmodel,andforradiation,thediscreteordinatemodelisused.Moreover,thermohydraulicprocessesinthemembranewallarealsoineludedintheheattransferprocess.Themodelwassuccessfullyappliedinsimulationsofa350-MWsupercriticalCFBboiler.Detaileddistributionsofsolidsconcentration,oxygen,heatflux,andworkingmediumtemperatureintheboilerfurnacearepresented.

简介：ThegoalofthisstudyistoanalyzethestatisticsofthebackscattersignalfrombovinecancellousboneusingaNakagamimodelandtoevaluatethefeasibilityofNakagami-modelparametersforcancellousbonecharacterization.Ultrasonicbackscattermeasurementswereperformedon24bovinecancellousbonespecimensinvitroandthebackscattersignalswerecompensatedforthefrequency-dependentattenuationpriortotheenvelopedetection.ThestatisticsofthebackscatterenvelopeweremodeledusingtheNakagamidistribution.Ourresultsrevealthatthebackscatterenvelopemainlyfollowedpre-Rayleighdistributions,andthedeviationsofthebackscatterenvelopefromRayleighdistributiondecreasedwithincreasingbonedensity.TheNakagamishapeparameter(i.e.,m)wassignificantlycorrelatedwithbonedensities(R=0.78–0.81,p<0.001)andtrabecularmicrostructures(|R|=0.46–0.78,p<0.05).Thescaleparameter(i.e.,?)andsignal-to-noiseratio(SNR)alsoyieldedsignificantcorrelationswithbonedensityandstructuralfeatures.Multiplelinearregressionsshowedthatbonevolumefraction(BV/TV)wasthemainpredictoroftheNakagamiparameters,andmicrostructureproducedsignificantlyindependentcontributiontothepredictionofNakagamidistributionparameters,explaininganadditional10.2%ofthevarianceatmost.TheinvitrostudyshowedthatstatisticalparametersderivedwithNakagamimodelmightbeusefulforcancellousbonecharacterization,andstatisticalanalysishaspotentialforultrasonicbackscatterboneevaluation.

简介：Thelargedesignfreedomofvariable-stiffness(VS)compositematerialpresupposesitspotentialforwideengineeringapplication.PreviousresearchindicatesthatthedesignofVScylindricalstructureshelpstoincreasethebucklingloadascomparedtoquasi-isotropic(QI)cylindricalstructures.Thispaperfocusesontheanti-bucklingperformanceofVScylindricalstructuresundercombinedloadsandtheefficientoptimizationdesignmethod.Twokindsofconditions,bendingmomentandinternalpressure,andbendingmomentandtorqueareconsidered.Influencesofthegeometricaldefects,ovality,onthecylinder'sperformancesarealsoinvestigated.Toincreasethecomputationalefficiency,anadaptiveKrigingmeta-modelisproposedtoapproximatethestructuralresponseofthecylinders.InthisimprovedKrigingmodel,amixedupdatingruleisusedinconstructingthemeta-model.Ageneticalgorithm(GA)isimplementedintheoptimizationdesign.TheoptimalresultsshowthatthebucklingloadofVScylindersinallcasesisgreatlyincreasedascomparedwithaQIcylinder.

简介：WehavecomprehensivelyinvestigatedthefrustratedJ1-J2-J3Heisenbergmodelonasimplecubiclattice.Thismodelallowsthreeregimesofmagneticorder,viz.,(π;π;π),(0;π;π)and(0;0;π),denotedasAF1,AF2,andAF3,respectively.Theeffectsoftheinterplayofneighboringcouplingsonthemodelarestudiedintheentiretemperaturerange.Thezerotemperaturemagneticpropertiesofthismodelarediscussedutilizingthelinearspinwave(LSW)theory,nonlinearspinwave(NLSW)theory,andGreen’sfunction(GF)method.ThezerotemperaturephasediagramsevaluatedbytheLSWandNLSWmethodsareillustrated,andareobservedtoexhibitdifferentparameterboundaries.Incertainregionsandalongtheparameterboundaries,thepossiblephasetransformationsdrivenbytheparametersarediscussed.TheresultsobtainedusingtheLSW,NLSW,andGFmethodsarecomparedwiththoseobtainedusingtheseriesexpansion(SE)method,andareobservedtobeingoodagreementwhenthevalueofJ2isnotclosetotheparameterboundaries.ThegroundstateenergiesobtainedusingtheLSWandNLSWmethodsareclosetothatobtainedusingtheSEmethod.Atfinitetemperatures,onlytheGFmethodisemployedtoevaluatethemagneticproperties,andthecalculatedphasediagramisobservedtobeidenticaltotheclassicalphasediagram.Theresultsindicatethatattheparameterboundaries,atemperature-drivenfirst-orderphasetransitionbetweenAF1andAF2mayoccuralongtheboundaryline.AlongtheAF1-AF3andAF2-AF3boundarylines,AF3islessstablethanAF1andAF2.OurcalculatedcriticaltemperatureagreeswiththatobtainedusingMonteCarlosimulationsandpseudofermionfunctionalrenormalizationgroupscheme.