简介:文章阐明了PBL教学法在“船舶强度与结构设计”课程教学中的应用,介绍了其具体实施步骤。实施效果显示,该方法取得了良好的教学效果,具有一定的参考意义。
简介:Strongrestrictionsonemissionsfrommarinepowerplants(particularlySOx,NOx)willprobablybeadoptedinthenearfuture.Inthispaper,acombinedsolidoxidefuelcell(SOFC)andsteamturbinefuelledbynaturalgasisproposedasanattractiveoptiontolimittheenvironmentalimpactofthemarinesector.TheanalyzedvariantofthecombinedcycleincludesaSOFCoperatedwithnaturalgasfuelandasteamturbinewithasingle-pressurewasteheatboiler.ThecalculationswereperformedfortwotypesoftubularandplanarSOFCs,eachwithanoutputpowerof18MW.Thispaperincludesadetailedenergyanalysisofthecombinedsystem.Massandenergybalancesareperformednotonlyforthewholeplantbutalsoforeachcomponentinordertoevaluatethethermalefficiencyofthecombinedcycle.Inaddition,theeffectsofusingnaturalgasasafuelonthefuelcellvoltageandperformanceareinvestigated.Ithasbeenfoundthatahighoverallefficiencyapproaching60%maybeachievedwithanoptimumconfigurationusingtheSOFCsystem.Thehybridsystemwouldalsoreduceemissions,fuelconsumption,andimprovethetotalsystemefficiency.
简介:Theprogressofeconomicglobalization,therapidgrowthofinternationaltrade,andthemaritimetransportationhasplayedanincreasinglysignificantroleintheinternationalsupplychain.Asaresult,worldwideseaportshavesufferedfromacentralproblem,whichappearsintheformofmassiveamountsoffuelconsumedandexhaustgasfumesemittedfromtheshipswhileberthed.Manyportshavetakenthenecessaryprecautionstoovercomethisproblem,whileothersstillsufferduetothepresenceoftechnicalandfinancialconstraints.Inthispaper,thebarriers,interconnectionstandards,rules,regulations,powersources,andeconomicandenvironmentalanalysisrelatedtoships,shore-sidepowerwerestudiedineffortstofindasolutiontoovercomehisproblem.Asacasestudy,thispaperinvestigatesthepracticability,costsandbenefitsofswitchingfromonboardshipauxiliaryenginestoshore-sidepowerconnectionforhigh-speedcraftscalledAlkaherawhileberthedattheportofSafaga,Egypt.Theresultsprovidethenationalelectricitygridconceptasthebesteconomicalselectionwith49.03percentofannualcostsaving.Moreover,environmentally,itcouldachieveanannualreductioninexhaustgasemissionsofCO2,CO,NOx,P.M,andSO2by276,2.32,18.87,0.825and3.84tons,respectively.