简介:Atthe'98shippingexpositionheldinstamford,connecticutUSAACTAMaritimepresident,richardthorsen,unveiledspeedportforthefirsttime,itisaconceptofnewcontainerterminalandoperatingsystem,whichtakesfulladvantageofnaturaltimemotionrelationshipsandthelatestcomputerandrobotictechnologies.
简介:Acomplianttowerismodeledasapartiallydry,partiallytapered,dampedTimoshenkobeamwiththesuperstructuremodeledasaneccentrictipmass,andanon-classicaldampedboundaryatthebase.Thefoundationismodeledasacombinationofalinearspringandatorsionalspring,alongwithparallellinearandtorsionaldampers(Kelvin-Voigtmodel).Thesuperstructureaddstothekineticenergyofthesystemwithoutaffectingthepotentialenergy,therebyreducingthenaturalfrequencies.Theweightofthesuperstructureactsasanaxialcompressiveloadonthebeam,reducingitsnaturalfrequenciesfurther.Theemptyspacefactorduetothetruss-typestructureofthetowerisincluded.Theeffectofsheardeformationandrotaryinertiaareincludedinthevibrationanalysis;withthenon-uniformbeammode-shapesbeingaweightedsumoftheuniformbeammode-shapessatisfyingtheendcondition.TheweightsareevaluatedbytheRayleigh-Ritz(RR)method,andverifiedusingfiniteelementmethod(FEM).Theweightofthesuperstructureactsasanaxialcompressiveloadonthebeam.Kelvin-Voigtmodelofstructuraldampingisincluded.Apartofthestructurebeingunderwater,thevirtualaddedinertiaisincludedtocalculatethewetnaturalfrequencies.Aparametricstudyisdoneforvariousmagnitudesoftipmassandvariouslevelsofsubmergence.ThecomputationalefficiencyandaccuracyoftheRayleigh-Ritzmethod,ascomparedtotheFEA,hasbeendemonstrated.Theadvantageofusingclosed-formtrialfunctionsisclearlyseenintheefficacyofcalculatingthevariousenergycomponentsintheRRmethod.
简介:2001年是新世纪,新千年的初始年,是“十五”计划的起步年,也是石化股份公司上市后的第一年,在新的一年里,安全生产将面临更加艰巨的任务,经受更加严峻的考验,首先,安全工作要适应股份公司上市后的新要求,上市后的石化股份公司要努力成为全球经济紧密关联的国际化公司,做到经营,管理公开透明,自觉接受国际资本市场的考验,接受投资者和证券监管机构的监督,安全与环保作为企业的重要工作,特别是作为直接影响企业形象乃至股价的外部最直观的监督项目,必须研究新情况,解决新问题,加大力度,提高水平,努力适应新发展,其次,安全工作要以受无成年繁重生产经营任务的考验,油田,炼油,化工,销售企业四大板块2001年的生产经营任务都比2000年有所加重,完成这些任务对安全生产工作提出了很高的要求,特别是长周期,高负荷,低成本,高回报将对安全生产工作构成巨大压力,第三,安全工作要经受进一步浓化改革带来的影响和冲击,2001年内,上市与非上市要彻底分开,关融分流任务要落实到位,这些从长远看十分必要的改革举措涉及干部职工的切身利益,在执行中会在一定程度上影响职工队伍的稳定,影响安全生产,面对严峻的形势,各级领导干部一定要充分提高认识,深入做好思想政治工作,统一思想,坚定信心,信中精力抓好安全工作,为集团公司实现全年与发展四大奋斗目标提供可靠的安全保障。