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58 个结果
  • 简介:OnMarch26,2010anunderwaterexplosion(UWE)ledtothesinkingoftheROKSCheonan.TheofficialMultinationalCivilian-MilitaryJointInvestigationGroup(MCMJIG)reportconcludedthatthecauseoftheunderwaterexplosionwasa250kgnetexplosiveweight(NEW)detonationatadepthof69mfromaDPRK'CHT-02D'torpedo.KimandGitterman(2012a)determinedtheNEWandseismicmagnitudeas136kgatadepthofapproximately8mand2.04,respectivelyusingbasichydrodynamicsbasedontheoreticalandexperimentalmethodsaswellasspectralanalysisandseismicmethods.ThepurposeofthisstudywastoclarifythecauseoftheUWEviamoredetailedmethodsusingbubbledynamicsandsimulationofpropellersaswellasforensicseismology.Regardingtheobservedbubblepulseperiodof0.990s,0.976sand1.030swerefoundincaseofa136NEWatadetonationdepthof8musingtheboundaryelementmethod(BEM)and3Dbubbleshapesimulationsderivedfora136kgNEWdetonationatadepthof8mapproximately5mportsidefromthehullcenterline.Hereweshowthroughanalyticalequations,modelsand3Dbubbleshapesimulationsthatthemostprobablecauseofthisunderwaterexplosionwasa136kgNEWdetonationatadepthof8mattributabletoaROKlittoral'landcontrol'mine(LCM).

  • 标签: CEPSTRUM SPECTROGRAM BUBBLE pulse TOROIDAL BUBBLE
  • 简介:<正>Glasgow,UK18th-20thAugust2014AbouttheconferenceTheconferencewillbringtogetherresearchers,practitionerstoaddressthesafetyandreliabilityissuesasapplicabletodifferentstagesintheanalysis,designconstructionandin-servicelifeofmarinestructuressuchasship,offshore,submergedstructuresandtherenewableenergystructures.Thiswillinvolveadvancedanalysisbothforstrengthandloadmodelinordertoestablishsafetylevelbothfordeterministicmodel(WSDmethod)andforreliabilitybaseddesign(LRFDmethod).Oneoftheaimsofthedesignshouldbetoachieveadequatebutnotexcessivelevelofsafetywhichcanbesatisfiedthroughreliabilitybasedmethodandthistakesintoaccountuncertaintiesofdesignvariables.CurrentmoderncodesaretryingtoprovidedesignproceduresonLRFDformatalthoughnoexplicitreliabilityanalysisisdonetoarrivethesepartialsafetyfactors.Thisconferencewilldealwithalltheseissuesandseehowthesetechniquesareappliedtovarioustypesofmarinestructures.Glasgow,thevenueforthisconferenceisacitywhichhaslotofattractions.TheworldfamousLoch-LomondisonlyfewmilesawayandEdinburghis50minutesjourneybytrain.Thecitywillalsohostthe2014CommonwealthGames.

  • 标签: 船舶安全 可靠性 国际会议 水下结构 离岸
  • 简介:Inordertostudytheeffectsofgeometricparametersoftherudderonthehydrodynamicperformanceofthepropeller-ruddersystem,thesurfacepanelmethodisusedtobuildthenumericalmodelofthesteadyinteractionbetweenthepropellerandruddertoanalyzetherelevantfactors.Theinteractionbetweenthepropellerandrudderisconsideredthroughtheinducedvelocities,whicharecircumferentiallyaveraged,sotheunsteadyproblemistranslatedtosteadystate.Aniterativecalculationmethodisuseduntilthehydrodynamicperformanceconverges.Firstly,thehydrodynamicperformanceofthechosenpropeller-ruddersystemiscalculated,andthecomparisonbetweenthecalculatedresultsandtheexperimentaldataindicatesthatthecalculationprogramisreliable.Then,thevariableparametersofrudderareinvestigated,andthecalculationresultsshowthatthepropeller-rudderspacinghasanegativerelationshipwiththeefficiencyofthepropeller-ruddersystem,andtherudderspanhasanoptimalmatchrangewiththepropellerdiameter.Futhermore,therudderchordandthicknessbothhaveapositivecorrelationwiththehydrodynamicperformanceofthepropeller-ruddersystem.

  • 标签: RUDDER GEOMETRIC parameters propeller-rudder system induced
  • 简介:Severalindustrialapplicationssuchaselectronicdevices,heatexchangers,gasturbineblades,etc.needcoolingprocesses.Theinternalcoolingtechniqueisproperforsomeapplications.Inthepresentwork,computationalsimulationsweremadeusingANSYSCFXtopredicttheimprovementsofinternalheattransferintherectangularribbedchannelusingdifferentcoolants.Severalcoolantssuchasair,steam,air/mistandsteam/mistwereinvestigated.Theshearstresstransportmodel(SST)isselectedbycomparingthestandardk-ωandOmegaReynoldsStress(ωRS)turbulencemodelswithexperimentalresults.Theresultsindicatethattheheattransfercoefficientsareenhancedintheribbedchannelwhileinjectingsmallamountsofmist.Theheattransfercoefficientsofair/mist,steamandsteam/mistincreaseby12.5%,49.5%and107%overthatofair,respectively.Furthermore,incomparisontoair,theair/mistheattransfercoefficientenhancesbyabout1.05to1.14timeswhenthemistmassfractionincreasesfrom2%to8%,respectively.Thesteam/mistheattransfercoefficientincreasesbyabout1.12to1.27timeshigherthanthatofsteamovertheconsideredrangeofmistmassfraction.

  • 标签: heat transfer RIB ROUGHNESS MIST rectangular
  • 简介:Inordertostudycavitationcharacteristicsofa2-Dhydrofoil,themethodthatcombinesnonlinearcavitationmodelandmixed-iterationisusedtopredictandanalyzethecavitationperformanceofhydrofoils.ThecavitationelementsarenonlinearlydisposedbasedontheGreenformulaandperturbationpotentialpanelmethod.Atthesametime,themethodthatcombinescavityshapeforfixedcavitylength(CSCL)iterationandcavityshapeforfixedcavitationnumber(CSCN)iterationisusedtoworkoutthethicknessandlengthofhydrofoilcavitations.Throughanalysisofcalculationresults,itcanbeconcludedthatthejumpofpressureandvelocitypotentiallyexistbetweencavitationendareaandnon-cavitationsareaonsuctionsurfacewhencavitationoccursonhydrofoil.Incertainanglesofattack,thecavitationnumberhasanegativeimpactonthelengthofcavitations.Andunderthesameangleofattackandcavitationnumber,thebiggerthethicknessofthehydrofoil,theshorterthecavitationslength.

  • 标签: 2-D HYDROFOIL CAVITATION performance nonlinear theory
  • 简介:Foralargefloatingvesselinwaves,radiationdampingisnotanaccuratepredictionofthedegreeofrollunlikeotherdegreesoffreedommotion.Therefore,togettheknowledgeofrollmotionperformanceofdeepwaterpipelaycranevesselsandtokeepthevesselworkingsafety,thepaperpresentstherelationshipbetweenaseriesofdimensionlessrolldampingcoefficientsandtherollresponseamplitudeoperator(RAO).Byusingtwokindsofempiricaldata,therolldampingisestimatedinthecalculationflow.Aftergettingtherolldampingcoefficientfromthemodeltest,apredictionofrollmotioninregularwavesisevaluated.Accordingtothewaveconditionintheworkingregion,shorttermstatisticsofrollmotionarepresentedunderdifferentwaveparameters.Moreover,therelationshipbetweenthemaximalrollresponseleveltopeakspectralwaveperiodandtherolldampingcoefficientisinvestigated.Resultsmayprovidesomereferencetodesignandimprovethiskindofvessel.

  • 标签: DEEPWATER pipelay CRANE vessel ROLL damping
  • 简介:文中依据客观故据资料,从决策支持,应急抢险,污染物围控与清除,应急队伍等8个方面系统分析了宁波港船我化学品泄漏应急处置能力现状,指出了不足之处.并提出了加强船栽化学品泄漏应急处置能力建设建议

  • 标签: 化学品 水上泄漏 应急处置 反应能力
  • 简介:Theobjectiveofthisworkistoanalysefatiguereliabilityofdeckstructuressubjectedtocorrelatedcrackgrowth.Thestressintensityfactorsofthecorrelatedcracksareobtainedbyfiniteelementanalysisandbasedonwhichthegeometrycorrectionfunctionsarederived.TheMonteCarlosimulationsareappliedtopredictthestatisticaldescriptorsofcorrelatedcracksbasedontheParis-Erdoganequation.Aprobabilisticmodelofcrackgrowthasafunctionoftimeisusedtoanalysethefatiguereliabilityofdeckstructuresaccountingforthecrackpropagationcorrelation.Adeckstructureismodelledasaseriessystemofstiffenedpanels,whereastiffenedpanelisregardedasaparallelsystemcomposedofplatesandarelongitudinal.Ithasbeenproventhatthemethoddevelopedherecanbeconvenientlyappliedtoperformthefatiguereliabilityassessmentofstructuressubjectedtocorrelatedcrackgrowth.

  • 标签: CRACK growth FATIGUE reliability DECK structures
  • 简介:T0KY0MOU组织港口当局累计检查船舶38067艘次,无缺陷通过11933艘次,滞留1422艘次,滞留率3.7%;滞留船舶中,船龄15年及以上老旧船舶802艘次,占564%,船龄最老的当属1954年建造客轮“PRINCESS”号。设备老化且疏于维护保养是导致滞留主要原因。

  • 标签: 滞留率 组织 备忘录 滞留船舶 老旧船舶 维护保养
  • 简介:Strongrestrictionsonemissionsfrommarinepowerplants(particularlySOx,NOx)willprobablybeadoptedinthenearfuture.Inthispaper,acombinedsolidoxidefuelcell(SOFC)andsteamturbinefuelledbynaturalgasisproposedasanattractiveoptiontolimittheenvironmentalimpactofthemarinesector.TheanalyzedvariantofthecombinedcycleincludesaSOFCoperatedwithnaturalgasfuelandasteamturbinewithasingle-pressurewasteheatboiler.ThecalculationswereperformedfortwotypesoftubularandplanarSOFCs,eachwithanoutputpowerof18MW.Thispaperincludesadetailedenergyanalysisofthecombinedsystem.Massandenergybalancesareperformednotonlyforthewholeplantbutalsoforeachcomponentinordertoevaluatethethermalefficiencyofthecombinedcycle.Inaddition,theeffectsofusingnaturalgasasafuelonthefuelcellvoltageandperformanceareinvestigated.Ithasbeenfoundthatahighoverallefficiencyapproaching60%maybeachievedwithanoptimumconfigurationusingtheSOFCsystem.Thehybridsystemwouldalsoreduceemissions,fuelconsumption,andimprovethetotalsystemefficiency.

  • 标签: marine STEAM TURBINE natural gas FUEL
  • 简介:Wavediffractionoftwoconcentricporouscylinderswithvaryingporositywasstudiedbyusingananalyticalmethodbasedoneigenfunctionmatching.Thefluiddomainaroundthecylindersisdividedintothreesub-domainsandineachsub-domainaneigenfunctionexpansionofthevelocitypotentialisobtainedbysatisfyingtheLaplaceequation,theboundaryconditionsonthefreesurfaceandontheseabed.Theunknowncoefficientsofeigenfunctionexpansionsaredeterminedbyboundaryconditionsontheporoushulls.Inthepaper,theboundaryconditionsarebasedupontheassumptionthattheflowintheporousmediumisgovernedbyDarcy’slaw.Twoporous-effectparametersappliedontwoporouscylindersarefunctionsoftheverticalcoordinateinsteadoftheconstant.Waveloadingontheouterandinnercylinderispresentedinthenumericalresults.

  • 标签: CONCENTRIC porous cylinders WAVE loading DIFFRACTION
  • 简介:文章探讨了能力本位下航海英语课程体系内涵,并从语言教学理论层面剖析了航海英语交际能力内在构成.提出能力本位下航海英语课程体系构建实践原则,最后结合《STCW公约》马尼拉修正案重新构建航海英语课程体系。

  • 标签: 能力本位 交际能力 航海英语 课程体系
  • 简介:文章说明了太宰治试图通过《灯笼》这部作品叙述自己苦于世人歧视、后又释怀心路历程,同时也表明了希望世人消除对弱者歧视愿望。

  • 标签: 灯笼 羞耻 盗贼 歧视
  • 简介:是什么使得通用电气、杜邦、宝洁这样公司出类拔萃?卓越产品?杰出员工?优秀领导者?都对。深究一下,它们成功背后还有另一个更为根本原因:选择合适经营战略。而要选择合适经营战略,不仅要分析经营环境及市场走势,不可或缺还有对自己及竞争者现行战略识别。本文就将在各班轮公司2012年年报基础上,分析市场总体变化情况、各大公司经营业绩经营战略。

  • 标签: 班轮公司 经营战略 市场走势 通用电气 经营环境 经营业绩
  • 简介:跌入谷底国际航运业毫不客气地终结了全球造船业上一轮繁荣,持续地对各大船企业形成致命冲击,“接单难、交船难、盈利难”等现象已成为广大船企必须面对难题。为此,不少船企加大了“转方式、调结构”力度,以期在不景气市场中求得生存乃至发展空间。

  • 标签: 造船业 国际航运业 企业 盈利
  • 简介:文章从高校财务投资回报风险、债务负担风险、筹资能力风险、财务管理效率风险、内部控制缺失风险等方面阐述了高校财务风险成因,提出了控制风险对策,以期为降低高校财务风险提供借鉴。

  • 标签: 高校 财务风险 成因与对策
  • 简介:文章针对当前职业岗位需求,以项目引领、任务驱动为导向,从改革思路、项目化设计、教学方法手段等方面,开展了“船体装配”课程改革探索,具有一定实践指导意义。

  • 标签: 高职教育 船体装配 项目化课程改革
  • 简介:文章介绍了当前非法中介存在方式危害,深入分析了其存在原因,并从加大宣传力度、切实推行便民服务措施、治理非法中介、加强队伍管理、建立联合执法工作机制、完善内部监督机制等方面提出了应对策略,以期为海事管理部门打击非法中介提供借鉴。

  • 标签: 海事部门 船舶代理 非法中介 对策