简介:Basedonfluidequations,weshowatime-dependentself-consistentnonlinearmodelforvoidformationinmagnetizeddustyplasmas.Thecylindricalconfigurationisappliedtobetterillustratetheeffectsofthestaticmagneticfield,consideringtheazimuthalmotionofthedusts.Thenonlinearevolutionofthedustvoidandtherotationofthedustparticlesaretheninvestigatednumerically.Theresultsshowthat,similartotheunmagnetizedone-dimensionalmodel,theradialiondragplaysacrucialroleintheevolutionofthevoid.Moreover,thedustrotationisdrivenbytheazimuthaliondragforceexertingonthedust.Astheazimuthalcomponentofionvelocityincreaseslinearlywiththestrengthofthemagneticfield,theazimuthalcomponentofdustvelocityincreasessynchronously.Moreover,theangularvelocitygradientsofthedustrotationshowasheareddustflowaroundthevoid.
简介:Alongwiththeflourishingofthewindenergyindustry,floatingoffshorewindturbineshavearousedmuchinterestamongtheacademiaaswellasenterprises.Inthispaper,theeffectsofthesupportingplatformmotionontheaerodynamicsofafloatingwindturbinearestudiedusingtheopensourceCFDframeworkOpenFOAM.Theplatformmotionresponses,includingsurge,heaveandpitch,aresuperimposedontotherotationofthewindturbine.Thrustandtorqueonthewindturbinearecomparedandanalysedforthecasesofdifferentplatformmotionpatternstogetherwiththeflowfield.Itisshownthatthemovementofthesupportingplatformcanhavelargeinfluencesonafloatingoffshorewindturbineandthusneedstobeconsideredcarefullyduringthedesignprocess.
简介:Background:Novelplayertrackingtechnologiescanchangetheunderstandingofperformancedeterminantsinteamsportsbyallowingtoaccuratelymeasuringtheactivitydemands.Theaimofthisstudywastoidentifyhowthedefensivepressureaffectsthetime-motionvariablesandthetechnicalactionsinbasketball.Methods:Twentyinternationalmaleplayers(age:16.05±2.09years,weight:73.13±8.10kg,height:183.10±5.88cm)playedtwo10minbasketballquarters,wheretheyusedaman-to-man1/4-courtdefenseuntilthe4thmin(F1/4),changedtoman-to-manfullcourt(FULL)for3minand,fromthe7thtothe10thminreturnedto1/4-courtdefense(S1/4).AcomputerizednotationalanalysiswasperformedusingSimiScoutandpositionaldatawerecapturedwiththeUbisenseRealTimeLocationSystem(meansamplingrate3.74±0.45Hzpertransmitter/player).Results:Thetime-motionvariablespresentedsimilarresultsbetweendefensiveconditions,showingatotaldistancecoveredaround90m/min.However,resultssuggestedpossibleverticaljumpimpairmentsinS1/4periods.Therewasmoredistancecoveredwhilejoggingintheoffensivecourt(38.15±12.17m/minoffensivecourtvs.32.94±10.84m/mindefensivecourt,p<0.05)andmoredistancecoveredwhilerunninginthedefensivecourt(16.41±10.27m/minoffensivecourtvs.19.56±10.29m/mindefensivecourt,p<0.05).Conclusion:Theseresultssuggesthowtoimprovetaskrepresentativenessduringspecificconditioningorgame-basedtrainingsituationsandalsotohelpcoaches’strategicdecisionsduringthegames.
简介:腱垂直地系在因此,物理腱压力的深理解要求的紧张腿平台(TLP)腱的全部的轴的变丑的决心,它是举,沥青,和澎湃的回答的联合。TLP的侧面的方面的垂直运动被结合巨浪并且组成沥青运动的部分。腱被连接到TLP的方面;因此,侧面的方面的全部的排水量与腱和全部的轴的压力的全部的变丑有关。因此,在TLP的方面调查全部的垂直反应是必要的。在自由的各种各样的度之间联合没在反应振幅操作员(RAO)被考虑。因此在频率领域分析,估计的垂直RAO是不完全的。在时间领域,另外,在TLP的中心的仅仅举运动典型地被学习;这个问题需要被处理。在这份报纸,我们在频率和时间领域在TLP的方面在垂直反应调查沥青运动的部分。数字结果在一些时期范围在TLP的边的垂直运动表明沥青运动的重要效果。
简介:Background:Thegreatertrochantermarkeriscommonlyusedin3-dimensional(3D)models;however,itsinfluenceonhipandkneekinematicsduringgaitisunclear.Understandingtheinfluenceofthegreatertrochantermarkerisimportantwhenquantifyingfrontalandtransverseplanehipandkneekinematics,parameterswhichareparticularlyrelevanttoinvestigateinindividualswithconditionssuchaspatellofemoralpain,kneeosteoarthritis,anteriorcruciateligament(ACL)injury,andhippain.Theaimofthisstudywastoevaluatetheeffectofincludingthegreatertrochanterintheconstructionofthethighsegmentonhipandkneekinematicsduringgait.Methods:3Dkinematicswerecollectedin19healthysubjectsduringwalkingusingasurfacemarkersystem.Hipandkneeangleswerecomparedacrosstwothighsegmentdefinitions(withandwithoutgreatertrochanter)attwotimepointsduringstance:peakkneeflexion(PKF)andminimumkneeflexion(MinKF).Results:Hipandkneeanglesdifferedinmagnitudeanddirectioninthetransverseplaneatbothtimepoints.Inthethighmodelwiththegreatertrochanterthehipwasmoreexternallyrotatedthaninthethighmodelwithoutthegreatertrochanter(PKF:-9.34°±5.21°vs.1.40°±5.22°,MinKF:-5.68°±4.24°vs.5.01°±4.86°;p<0.001).Inthethighmodelwiththegreatertrochanter,thekneeanglewasmoreinternallyrotatedcomparedtothekneeanglecalculatedusingthethighdefinitionwithoutthegreatertrochanter(PKF:14.67°±6.78°vs.4.33°±4.18°,MinKF:10.54°±6.71°vs.-0.01°±2.69°;p<0.001).Smallbutsignificantdifferencesweredetectedinthesagittalandfrontalplaneanglesatbothtimepoints(p<0.001).Conclusion:Hipandkneekinematicsdifferedacrossdifferentsegmentdefinitionsincludingorexcludingthegreatertrochantermarker,especiallyinthetransverseplane.Thereforewhenconsideringwhethertoincludethegreatertrochanterinthethighsegmentmodelwhenusingasurfacemarkerstocalculate3Dkinematicsformovementassessment,iti
简介:Adesignofsemi-submersibleplatformismainlybasedontheextremeresponseanalysisduetotheforcesexperiencedbythecomponentsduringlifetime.Theexternalloadscaninducetheextremeairgapresponseandpotentialdeckimpacttothesemi-submersibleplatform.Itisimportanttopredictairgapresponseofplatformsaccuratelyinordertocheckthestrengthoflocalstructureswhichwithstandthewaveslammingduetonegativeairgap.Thewindloadcannotbesimulatedeasilybymodeltestintowingtankwhereasitcanbesimulatedaccuratelyinwindtunneltest.Furthermore,fullscalesimulationofthemooringsysteminmodeltestisstillatuffworkespeciallythestiffnessofthemooringsystem.Owingtotheabovementionedproblem,themodeltestresultsarenotaccurateenoughforairgapevaluation.Theaimofthispaperistopresentsensitivityanalysisresultsofairgapmotionwithrespecttothemooringsystemandwindloadforthedesignofsemi-submersibleplatform.Thoughthemodeltestresultsarenotsuitableforthedirectevaluationofairgap,theycanbeusedasagoodbasisfortuningtheradiationdampingandviscousdraginnumericalsimulation.Inthepresenteddesignexample,anumericalmodelistunedandvalidatedbyANSYSAQWAbasedonthemodeltestresultswithasimple4linesymmetricalhorizontalsoftmooringsystem.Accordingtothetunednumericalmodel,sensitivityanalysisstudiesofairgapmotionwithrespecttothemooringsystemandwindloadareperformedintimedomain.Threemooringsystemsandfivesimulationcasesaboutthepresentedplatformaresimulatedbasedontheresultsofwindtunneltestsandsea-keepingtests.Thesensitivityanalysisresultsarevaluableforthefloatingplatformdesign.