简介:Consideringtheheterogeneityofgeomechanicalmaterials,seismicityduringbrittlerockfailureundercompressiveloadingonthesamplewithanoriginalweakzoneissimulatedbyusingrockfailureprocessanalysiscode(RFPA2D).Therun-throughprocessofweakzone,theformingofnewfaultandassociatedmicro-seismicitiesarestudied.Themodelingdemonstratesthetotalprocessofsourcedevelopmentofearthquakefromdeformation,micro-failuretocollapseandthebehavioroftemporal-spatialdistributionofmicro-seismicities.Thestress,strainandthetemporal-spatialdistributionofmicro-seismicitieslife-likelyportrayedthephenomenaoflocalizationandtemporal-spatialtransitions,whichissimilartothoseobservedinourrealcrust.Also,theresultsobtainedinsimulationsareinagreementwithorsimilartothereportedexperimentalobservations.
简介:在世界的许多区域,一座桥将在它的期望的服务生活期间经历多重极端危险。州的高速公路和交通官员(AASHTO)的当前的美国协会负担和电阻因素设计(LRFD)说明基于失败可能性被提出,它充分为死了的负担和非极端的实时负担被校准。对地震负担效果的设计独立被建立。设计对搜索效果被使用能力减小的概念也独立提出(或增加搜索深度)。而且,搜索效果因为后者用基于力量的分析被提出,不能直接被连接到一个LRFD限制状态方程。这份报纸(在二部分)介绍一个基于概率的过程由于卡车在桥上估计联合危险效果,地震并且搜索,由对待效果作为相等的负担效果搜索以便它能在基于可靠性的失败计算被包括。部分地我这个系列,为把scour深度当作相等的负担效果的一般原则被介绍。在第二部分,相应的桥失败概率,出现象同时让卡车负担和等价物搜索负担效果一样搜索份量上被讨论。有条件的部分失败可能性和必要条件的关键公式被建立。以便说明方法论,死者的一个例子,卡车,地震并且在一个简单的桥堆积基础上搜索效果被代表。
简介:SulfatechitosanderivativeshavegoodsolubilityandtherapeuticeffectonthecellmodelofNAFLD.TheaimofthisstudywastoexaminethetherapeuticeffectofsulfatechitosanderivativesonNAFLD.ThemaleWistarratswereorallyfedhighfatemulsionandreceivedsulfatechitosanderivativesfor5weekstodeterminethepre-treatmenteffectofsulfatechitosanderivativesonNAFLD.ToevaluatethetherapeuticeffectofsulfatechitosanderivativesonNAFLD,theratswereorallyfedwithhighconcentrationemulsionfor5weeks,followedbysulfatechitosanderivativesfor3weeks.Histologicalanalysisandbiomedicalassaysshowedthatsulfatechitosanderivativescandramaticallypreventthedevelopmentofhepaticsteatosisinhepatocytecells.Inanimalstudies,pre-treatmentandtreatmentwithsulfatechitosanderivativessignificantlyprotectedagainsthepaticsteatohepatitisinducedbyhighfatdietaccordingtohistologicalanalysis.Furthermore,increasedTC,ALT,MDA,andLEPinNAFLDweresignificantlyamelioratedbypre-treatmentandtreatmentwithsulfatechitosanderivatives.Furthermore,increasedTG,AST,andTNF-αinNAFLDweresignificantlyamelioratedbytreatmentwithsulfatechitosanderivatives.Sulfatechitosanderivativeshavegoodpre-treatmentandtherapeuticeffectonNAFLD.
简介:-Theshearfailureofarigid-plasticdentedclampedtubularbeamunderthelateralimpactofamassisinvestigated.Boththedentingandtheimpactpointareinthemiddlespanofthebeam.Itisassumedthatdentingdoesnotspreadduringtheshearsliding.Numericalresultsshowthattheaxialforceandlateraldeflectionofthebeamareverysmallatthemomentoftheoccurenceofshearfailure,whichmeansthatthefinitedeformationeffectcanbeneglectedintheshearfailureanalysis.Also,someaspectsoftheinitialimpactenergyareinvestigated.
简介:Experimentsonsonictransmissionshowthataslabstonecandirectlytransmitpartoftheenergyofawaveexcitedbyknockingorbyatransducerintotheair.Theotherpartofthewaveenergycangeneratethenormalmodeofvibrationontheslabstoneandexcitemeasurableacousticsignalsintheair.Thedominantfrequencyisrelatedtothesizeoftheslabstone.Theseresultsindicatethattheacousticemission(AE)inrockalsodisplayssimilarbehaviorifthesourceisshallow.Itisdemonstratedthatwiththenucleationandpropagationofcracks,thedominantfrequencyoftheradiatedwavewillbelower.Whenthefrequencybecomesverylow,thewavecanbetransmittedthroughtherockintotheairandbereceivedbyamicrophone.Accordingtothetheoryofsimilarityofsize,therewillbelow-frequencywavesbeforestrongearthquakesbecauseofnucleationofcracks,whichcanbereceivedbyspeciallow-frequencytransducersorinfrasonicdetectors.Beforeearthquakes,themechanismofprecursorscouldbeverycomplicated.Theymightbeproducedbyplasticcreeporattributedtoliquidsbutnotbrittlefractureinmostcases.Sotheperiodsoftheproducedwaveswillbelonger.Thisperhapsaccountsforthelackofforeshocksbeforemanystrongearthquakes.
简介:TheeffectsonhepaticEROD(7-ethoxyresorufinO-deethylase)inMugilso-iuyexposedtobenzo(a)pyrene(BaP),pyreneandtheirmixturesofequalconcentrationwereinvestigated,atconcentrationsof0.1,1.0,5.0,10.0,50.0μg/dm3,inexperimentalcondition.Time-effectsanddoseresponseofthebiochemicalindexswereobserved.TheresultsshowedthatthehepaticERODactivitieswereinducedbytheexposureofBaP,pyreneandtheirmixturesathighconcentration.Dose-responseconnectionswerethatthehepaticERODactivitieswereelevatedwithincreasingconcentrationofthepollutants.ThecombinedeffectofBaPandpyreneat1:1concentrationratioonhepaticERODactivitywasantagonism.
简介:Oysterextractisaneffectivebioactivitycomponent.Ithasabundantnutritionalvalueandantiviral,antitumorandimmunedefensefunctions.Theroleofoysterextractintreatingliverinjuryhasbeenpaidmoreattention.WeuseWistarratstomakealcoholicliverdiseasemodelthroughinjectingalcoholintorats'stomachs.Theseratswererandomlydividedintofivegroups:modelgroup,controlgroup,low-dose,middle-doseandhigh-doseexperimentalgroupwithadoseof0.12gkg-1,0.40gkg-1,and1.20gkg-1alcoholic.Afternineweeks,serumbiomarkers(ALT,AST,TGandTCHO),malondialdehyde(MDA),glutathione(GSH),C3a,C5a,IL-17,TNF-ɑ,anti-MAA-HASIgG,CD3+,CD4+,CD8+,NKcellactivationandzinccontentwereassessed.Theresultsshowedthattheserumbiomarkers(ALT,AST,TGandTCHO),MDAcontent,anti-MAA-HSAIgG,serumC3a,C5aIL-17andTNF-ɑlevelsofoysterextracttreatmentgroupsweresignificantlydecreasedincomparisonwithmodelgroup.Onthecontrary,GSHshowedadversetrend.SerumCD3+,CD4+andNKcellactivationweresignificantlyincreasedinmiddle-dosegroupandhigh-dosegroupcomparedwithmodelgroup,andtherewasdecreaseofCD8+activityinhigh-dosegroup.PlasmaZnlevelwasdecreasedinmodelgroupcomparedwiththatincontrolgroup.Meanwhile,MeanplasmaZnlevelsincreaseddramaticallyfollowingthedoseincreaseofagivenoysterextract.
简介:On26thOctober2015,anMw7.5earthquakestrucknorthernPakistan,withitsepicenterlocated45kmsouthwestofJarmintheHinduKushregionofAfghanistan.Theearthquakeresultedfromreversefaultingatadepthof210km,resultingin280fatalitiesandsubstantialdamagetosome109,123buildings.Regionalseismicity,characteristicsofrecordedstrongmotions,damagestatistics,andbuildingperformanceobservationsarepresented.Earthquakedamagewasmostlyconstrainedtoseismic-deficientunreinforcedmasonry(URM)buildings.Typicalfailuremodesincludedtoppledminarets,partialorcompleteoutofplanecollapseofURMwalls,diagonalshearcrackinginpiers,flexuralcrackinginspandrels,cornerdamage,poundingdamage,anddamageduetogroundsettlement.ThemajorityofhumanlossresultedduetofailureofURMwallsandsubsequentroofcollapse.URMbuildingslocatedinruralhillyareasclosertotheepicentersufferedmoreintenseandfrequentdamagethanurbanURMbuildingslocatedfartherawayinlargercities.
简介:Theloadandcorrosioncausedbytheharshmarineenvironmentleadtotheseveredegradationofoffshoreequipmentandtotheircompromisedsecurityandreliability.Inthequantitativeriskanalysis,thefailuremodelsaredifficulttoestablishthroughtraditionalstatisticalmethods.Hence,thecalculationoftheoccurrenceprobabilityofsmallsampleeventsisoftenmetwithgreatuncertainty.Inthisstudy,theBayesianstatisticalmethodisimplementedtoanalyzetheoilandgasleakagesofFPSOinternalturret,whichisatypicalsmallsampleriskbutcouldleadtoseverelosses.Accordingtothecorrespondingfailuremechanism,twoBayesianstatisticalmodelsusingtheWeibulldistributionandlogarithmicnormaldistributionasthepopulationdistributionareestablished,andtheposteriordistributionofthecorrespondingparametersiscalculated.TheoptimalBayesianstatisticalmodelisdeterminedaccordingtotheBayesianinformationcriterionandAkaikecriterion.Onthebasisofthedeterminedoptimalmodel,thecorrespondingreliabilityindexissolvedtoprovidebasicdataforthesubsequentriskassessmentsofFPSOsystems.
简介:自从增强的水泥(RC)的很当前的地震能力评估,框架结构被任何一个静电干扰闲差事分析(PA)或动态时间历史分析实现,与象柱,横梁和墙的如此的主要结构的部件上的塑料绞链(PH)的多样的背景,复杂行为砍在横梁列关节(BCJ)的失败通常在主要地震期间被忽视。这研究建议新非线性的PA过程考虑砍在BCJ的失败并且寻求估计实际损坏到RC结构。基于FEMA-356的说明,由在塑料绞链的地点上斜放的二口非线性的生气神气组成的一个简化联合模型被建立,允许复杂PA被表现。为了验证这个方法,能力曲线的分析结果和失败的有效性,机制源于框架与试验性的大小相比的三不同动物完全长大的RC。由考虑砍在BCJ的失败,建议非线性的分析过程能被用来估计RC框架的结构的行为包括地震能力和关节的进步失败顺序,以一种精确、有效的方式。
简介:Ingeneral,earthquakecyclerelatedtoearthquakefaultingcouldincludefourmajorprocesseswhichcouldbedescribedby(1)faultlocking,(2)self-accelerationornucleation(possibleforeshocks),(3)coseismicslip,and(4)post-stressrelaxationandafterslip.Asuddenstaticstresschange/perturbationinthesurroundingcrustcanadvance/delaythefaultinstabilityorfailuretimeandmodifyearthquakerates.Basedonasimpleone-dimensionalspring-sliderblockmodelwiththecombinationofrate-and-statedependentfrictionrelation,inthisstudy,wehaveapproximatelyderivedthesimpleanalyticalsolutionsofclockadvance/delayoffaultfailurescausedbyasuddenstaticCoulombstresschangeappliedinthedifferenttemporalevolutionperiodsduringanearthquakefaulting.Theresultshavebeenusedinthephysics-basedexplanationofdelayedcharacteristicearthquakeinParkfieldregion,California,inwhichthenextcharacteristicearthquakeofM6.0after1966occurredin2004insteadofaround1988accordingtoitscharacteristicreturnperiodof22years.Atthesametime,theanalyticalsolutionsalsoindicatethatthetimeadvance/delayinCoulombstresschangederivedbythedislocationmodelhasacertainlimitationandfundamentalflaw.Furthermore,wediscussedtheessentialdifferencebetweenrate-andstate-variableconstitutive(R–S)modelandCoulombstressmodelusedcommonlyincurrentearthquaketriggeringstudy,anddemonstratedthat,infact,theCoulombstressmodelcouldbeinvolvedintheR–Smodel.Theresults,wehaveobtainedinthisstudy,couldbeusedinthedevelopmentoftime-dependentfaultinteractionmodelandtheprobabilitycalculationrelatedtothetime-dependentandrenewalearthquakepredictionmodel.
简介:Thispaperpresentstwokinematicfailuremechanismsofthree-dimensionalrectangularfootingrestingonhomogeneousundrainedclayfoundationunderuniaxialverticalloadinganduniaxialmomentloading.ThefailuremechanismunderverticalloadingcomprisesaplanestrainPrandtl-typemechanismoverthecentralpartofthelongerside,andthesizeofthemechanismgraduallyreducesattheendsofthelongersideandovertheshortersideasthecornerofrectangularfootingisbeingapproachedwherethedirectionofsoilmotionremainsnormaltoeachcorrespondingsiderespectively.Thefailuremechanismundermomentloadingcomprisesaplanestrainscoopslidingmechanismoverthecentralpartofthelongerside,andtheradiusofscoopslidingmechanismincreaseslinearlyattheendsofthelongerside.Onthebasisofthekinematicfailuremechanismsmentionedabove,theverticalultimatebearingcapacityandtheultimatebearingcapacityagainstmomentormomentultimatebearingcapacityareobtainedbyuseofupperboundlimitanalysistheory.Atthesametime,numericalanalysisresults,Skempton'sresultsandSalgadoetal.'sresultsarecomparedwiththisupperboundsolution.Itshowsthatthepresentedfailuremechanismsandplasticlimitanalysispredictionsarevalidated.Inordertoinvestigatethebehaviorsofundrainedclayfoundationbeneaththerectangularfootingsubjectedtothecombinedloadings,numericalanalysisisadoptedbyvirtueofthegeneral-purposeFEMsoftwareABAQUS,wheretheclayisassumedtoobeytheMohr-Coulombyieldingcriterion.ThefailureenvelopeandtheultimatebearingcapacityareachievedbythenumericalanalysisresultswiththevaryingaspectratiosfromlengthLtobreadthBoftherectangularfooting.ThefailuremechanismsofrectangularfootingwhicharesubjectedtothecombinedverticalloadingVandhorizontalloadingH(VerticalloadingVandmomentloadingM,andhorizontalloadingHandmomentloadingMrespectivelyareobservedinthefiniteelementa
简介:Inthisstudy,threerapidrepairtechniquesareproposedtoretrofitcircularbridgepiersthatareseverelydamagedbytheflexuralfailuremodeinmajorearthquakes.Thequasi-statictestsonthree1:2.5scaledcircularpierspecimensareconductedtoevaluatetheefficiencyoftheproposedrepairtechniques.Forthepurposeofrapidrepair,therepairprocedureforallthespecimensisconductedwithinfourdays,andthebehavioroftherepairedspecimensisevaluatedandcomparedwiththeoriginalones.Afiniteelementmodelisdevelopedtopredictthecyclicbehavioroftherepairedspecimensandthenumericalresultsarecomparedwiththetestdata.Itisfoundthatalltherepairedspecimensexhibitsimilarorlargerlateralstrengthanddeformationcapacitythantheoriginalones.Theinitiallateralstiffnessofalltherepairedspecimensislowerthanthatoftheoriginalones,whiletheyshowahigherlateralstiffnessatthelaterstageofthetest.Nonoticeabledifferenceisobservedfortheenergydissipationcapacitybetweentheoriginalandrepairedpierspecimens.Itissuggestedthattherepairtechniqueusingtheearly-strengthconcretejacketconfinedbycarbonfiberreinforcedpolymer(CFRP)sheetscanbeanoptimalmethodfortherapidrepairofseverelyearthquake-damagedcircularbridgepierswithflexuralfailuremode.
简介:Theacutetoxiclevelsofformalintoamarinered-tidedinoflagellateProrocentrumminimumSchiller(Mastigophora,Dinoflagellida)weredeterminedbylinearregressionanalysis.Thedataobtainedrevealedthatthereisacloseregressionrelationshipbetweenlogarithmicconcentrationsofformalinandmortalityprobitscalesoftheorganismwhenexposuretimesare1,2,6,12,24h.Themedianlethalconcentrations(LC50values)obtainedfromcorrelationanalysisfortheseexposuretimes(with95%confidenceintervals),were11.83,6.76,4.37,4.27and3.98mgL^-1respectively.AtoxicitycurvewasobtainedtoconnecttheexposuretimeandLC50valuefromthecorrelationbetweenthem.TheresultsindicatedthatP.minimumcouldbekilledorfixedbyformalinintheconcentrationrangeof4-12mgL^-1within1-24h.
简介:桥的以前的失败分析典型地独立集中于基础失败或上层建筑失败。在一座实际的桥,然而,地震导致的基础失败和上层建筑失败可以影响对方。而且,以前的研究典型地使用简化模型分析桥失败;然而,与使用相比在计算精确性有固有的缺点一详细说明三维(3D)有限元素(FE)模型。相反地,一个详细3DFE模型要求更计算的费用,和3D元素的一个合适的侵蚀标准是必要的。在这份报纸,包括一个相应侵蚀标准,一个多尺度的FE模型显著地被求婚并且验证那个罐头由建模与高精确减少计算费用增强的水泥(RC)的伪dynamic测试墩。一座连续RC桥的地震失败的数字模拟基于用LS-DYNA为方法建模的多尺度的FE被执行。桥,各种各样的连接力量和双向刺激的非线性的性质被考虑。数字结果证明连接的失败将导致girders的大跳的回答。墩的非线性的变丑将加重跳的损坏。而且,双向地震将导致怪癖的跳到girders和不同失败模式到邻近的墩。
简介:在台湾的Barlin水坝的失败,中国为在为快速的侵蚀和隧道恢复追随者建模评估概念提供重要案例研究故意、意外的水坝移动。我们使用了1D和quasi-2D的现在的建模努力解开了hydraulics和沉积模型(NETSTARS)建水坝评估discretization和parameterization怎么影响thefitofbedelevationpredictions到列在后面的观察失败。我们的分析评估了模型敏感到过去常定义剖面图的溪流试管的沉积运输功能,活跃的层厚度,和数字。结果显示那一)模型比到流试管的数字对活跃的层厚度和沉积运输功能更敏感,b)水坝移动模型的开发是可能的得益于及时改变活跃的层厚度,并且c)增加的侧面的discretization不看起来改善模型在我们的地点装入陡峭、很快改变的河环境。我们与之间的差别的讨论得出结论,识别对的需要,和1D的一般使用,quasi-2D,并且充分,2D在水坝移动和失败分析当模特儿。
简介:Rockexperimentresultsindicatethattheload/unloadresponseratio(LURR)ofrocksexpressedviastrainenergymayhavesingularornegativevalueafterthestressintherockreachesitsmaximumbeforerockfailureorwhentherockgoesintothestrain-weakeningphase.Theuniversalityofthisphenomenonisdiscussed.ExpressedviastrainorstrainenergyandthetraveltimeofPwave,thevariationformofthereciprocalofLURRduringtheprocessofrockfailurepreparationisderived.TheresultsshowthatafterasharpdecreasethereciprocalofLURRreachesitsminimumwhenthemainfractureoftherockisabouttoappear.Thisfeaturecanbetakenasanindicationthattherockmainfractureisimpending.