简介:Compressivesensingisarevolutionaryideaproposedrecentlytoachievemuchlowersamplingrateforsignals.Intheimageapplicationwithlimitedresourcesthecameradatacanbestoredandprocessedincompressedform.Analgorithmformovingobjectandregiondetectioninvideousingacompressivesamplingisdeveloped.Thealgorithmestimatesmotioninformationofthemovingobjectandregionsinthevideofromthecompressivemeasurementsofthecurrentimageandbackgroundscene.Thealgorithmdoesnotperforminversecompressiveoperationtoobtaintheactualpixelsofthecurrentimagenortheestimatedbackground.Thisleadstoacomputationallyefficientmethodandasystemcomparedwiththeexistingmotionestimationmethods.Theexperimentalresultsshowthatthesamplingratecanreduceto25%withoutsacrificingperformance.
简介:压缩力量,氯化物穿入抵抗和二高效的水泥的微观结构不到三被检验治好条件。治好的条件包括治好的标准(SC),治好匹配(MC,哪个工具在温度治好的封上的具体标本控制了盒子)并且根据温度的发展法律裸体水泥(NMC)治好匹配在地点上在集体水泥测量了。结果显示在MC和NMC下面的水泥在SC下面比那显示出更高的抵抗到氯化物穿入。在MC下面的水泥在NMC下面比那些有稍微更低的氯化物穿入,但是在NMC下面的标本的压缩力量比在在56d的MC下面的那高。另外,在NMC和MC下面具体比在SC下面有更高早的力量,特别在早年龄。然而,治好在248白天影响水泥的压缩力量的条件的顺序是:SC>NMC>MC。
简介:Concreteinreinforcedconcretestructure(RC)isgenerallyundersignificantcompressivestressload.Toguaranteerequiredqualityandductility,varioustestshavetobeconductedtomeasuretheconcrete'scompressivestrengthbasedonACI(AmericanConcreteInstitute)code.Investigationsofrecentdevastatingcollapsesofstructuresaroundtheworldshowedthatsomeofthecollapsesdirectlyresultedfromthepoorqualityoftheconcrete.Thelessonlearnedfromthesetragediesisthatguaranteeinghighqualityofconcreteisoneofthemostimportantfactorsensuringthesafetyofthereinforcedconcretestructure.Inordertoensurehighqualityofconcrete,anewmethodforanalyzingandevaluatingtheconcreteproductionprocessiscalledfor.Inthispaper,theindicesoffitandstabledegreeareproposedasbasistoevaluatethefitnessandstabilityofconcrete'scompressivestrength.Thesetwoindicesarecombinedtodefineandevaluatethequalityindexofthecompressivestrengthofconcrete.Principlesofstatisticsareusedtoderivethebestestimatorsoftheseindices.Basedontheoutcomeofthestudy,aconcretecompressivestrengthqualitycontrolchartisproposedasatooltohelptheevaluationprocess.Finally,anewevaluationproceduretoassessthequalitycontrolcapabilityoftheindividualconcretemanufacturerisalsoproposed.
简介:Inordertoimprovethecompressivestrengthofxonotlite,thepretreatedquartzpowder,slakedCaO,additive,deionizedwater(water-solidratioof30)wereplacedinamagneticallystirredautoclave,andthecorrespondingproductswereobtainedafterincubatingat220℃for0,1,3and6h,respectivelytoexplorethesyntheticprocessofxonotlite.Inthepreparedxonotlitepowder,0,5%,10%,15%and20%(bymass,thesamehereinafter)ofpre-treatedceramicstaplefiberswereadded,andtwosetsofspecimenwiththespecificationsofφ50mm×35mmweremoldedbypressedfiltration.Onesetofspecimenswerenotsintered,andtheothergroupwasfiredat1000℃for2htoexploretheeffectofceramicfiberadditiononthecompressivestrengthbeforeandaftersinteringofxonotlite.TheresultsshowthatC-S-Hgelisfirstsynthesizedinthesynthesisofxonotlite,andthentheC-S-Hgelistransformedtoformtobermlite,atlasttobermlitefullyreactstoproducexonotlite.Theadditionofceramicfiberenhancesthecompressivestrengthofthexonotlitebeforeandaftersintering.Whenthe15%ceramicfiberisadded,thecompressivestrengthisthehighest.Thespecimensbeforeandafterthehightemperaturefiringcontainxonotlitephaseandcalciumsilicatephase,respectively,andthecompressivestrengthofthefiredspecimensishigherthanthatofthegreenones.
简介:裂口Hopkinson压力酒吧(SHPB)技术被用来与不同钢纤维内容决定反应粉末水泥(RPC)的动态力量。有不同厚度的脉搏shapers的二种类型被认为减少high-frequency-oscillation效果并且在某个变丑范围上完成将近经常的紧张率。像水泥的材料的压缩力量是hydrostatic-stress-dependent,这被知道,并且明显的动态力量改进来自两个静水力学的压力和紧张的效果评价。以便区分他们,数字方法被用来在RPC的动态压缩强度上计算静水力学的应力,然后真紧张率效果的贡献被决定。另外,动态力量和RPC的失败模式上的钢纤维的效果被讨论。
简介:在相等的压缩力量的前提上把臼的力量弄弯上的矿物质混合的影响被调查。三矿物质混合(苍蝇灰,扎根的成粒的强风炉子炉渣和钢炉渣)被使用。在这研究的矿物质混合的增加的数量从22.5%~60%,并且water-to-binder比率从0.34~0.50。与相等的压缩力量,不同的臼能与他们的弯曲力量在如此的一份下降订单被安排:水泥苍蝇灰臼,水泥臼,cement-GGBS臼,和水泥钢炉渣臼。与一样的压缩力量,越高钢炉渣内容和water-to-binder比率,越多降低臼的弯曲力量。然而,矿物质混合内容的效果和水泥苍蝇灰臼和cement-GGBS臼的弯曲力量上的water-to-binder比率是远不引人注目的。
简介:Inthispaper,anexperimentalstudyonthesulphateattackresistanceofhigh-performanceconcrete(HPC)withtwodifferentwater-to-binderratios(w/b)undercompressiveloadingispresented.Thesulphateconcentration,compressivestrength,andthemasschangeintheHPCspecimensweredeterminedforimmersioninaNa2SO4solutionoverdifferentdurationsunderexternalcompressiveloadingbyself-regulatingloadingequipment.Theeffectsofthecompressivestress,thew/bratio,andtheNa2SO4solutionconcentrationontheHPCsulphateattackresistanceundercompressiveloadingwereanalysed.TheresultsshowedthattheHPCsulphateattackresistanceundercompressiveloadingwascloselyrelatedtothestresslevel,thew/bratio,andtheNa2SO4solutionconcentration.Applyinga0.3stressratioforthecompressiveloadingorreducingthew/bratioclearlyimprovedtheHPCsulphateattackresistance,whereasapplyinga0.6stressratioforthecompressiveloadingorexposingtheHPCtoamoreconcentratedNa2SO4solutionacceleratedthesulphateattackandHPCdeterioration.
简介:QingdaoJiaozhouBaysubseatunnelisthesecondself-builttunnelinChinawiththedesignedservicelifeover100years.Thedurabilityofliningconcreteareoneofanimportantfactorstodeterminatetheservicelifeoftunnel.Consideringthemainenvironmentalloadsandmechanicalloadsofsubseatunnel,thedurabilitypropertiesofliningconcreteundercombinedactionofcompressiveloadandcarbonationhasbeenstudiedthroughthecriticalcompressiveloadtest,acceleratedcarbonationtest,naturalcarbonationtestandcapillarysuctiontest.Thetestsresultsshowthatcriticalcompressiveloadapparentlyacceleratesthecarbonationanddeterioratestheanti-permeabilityofconcrete.Underthecombinedactionofcriticalcompressiveloadandcarbonation,thedurabilityofliningconcretedecreases.Basedonthecarbonizationlifecriteriaandresearchresults,forthehigh-performanceconcretewithproposedmixratio,thepredictedservicelifeofliningconcreteforJiaozhoubaysubseatunnelisabout80yearswhichfailstoreachtherequiredservicelife.Itisnecessarytoadoptothermeasurementssimultaneouslytoimprovethedurabilityofliningconcrete.
简介:AmodelofcrosslinkerunbindingisimplementedinahighlycoarsegrainedgranularmodelofF-actincytoskeleton.WeemploythisspecificgranularmodeltostudythemechanismsofthecompressiveresponsesofF-actinnetworks.ItisfoundthatthecompressiveresponseofF-actincytoskeletonhasdependencyonthestrainrate.TheevolutionofdeformationenergyinthenetworkindicatesthatcrosslinkerunbindingeventscaninducetheremodellingofF-actincytoskeletoninresponsetoexternalloadings.TheinternalstressinF-actincytoskeletoncanefficientlydissipatewiththehelpofcrosslinkerunbinding,whichcouldleadtothespontaneousrelaxationoflivingcells.
简介:许多设计材料随紧张率的增加表明他们的压缩强度的动态改进,它在材料模型被包括了在影响和强风负担下面改进材料和结构的回答的数字模拟的可靠性。设计以hydrostatic-stress-sensitive方式表现的材料的一个范围的动态压缩强度上的紧张率效果被调查。hydrostatic-stress-sensitive材料的压缩强度的动态改进可以包括导致惯性的侧面的监禁效果,这被结束,作为一个non-strain-rate因素,它可以极大地提高这些材料的压缩强度。一些实验公式可以基于紧张率在这些hydrostatic-stress-sensitive材料的压缩强度上完成的动态压力紧张大小在预言上,并且这样过高估计结构的抵抗到影响和强风负担,导致保护的结构的非保守的设计。
简介:Themajorobjectiveofthisresearchwastodiscusstheeffectsofloadingrateontheflexural-tensionpropertiesanduniaxialcompressivestrengthofmicro-surfacingmixtureusingthree-pointbendingtestanduniaxialcompressivetestrespectively.Asapreventivemaintenancesurfacetreatmentonasphaltpavement,micro-surfacingwasformedonthebasisoftheISSArecommendationofanoptimummicro-surfacingdesign.Testswereconductedoverawiderangeoftemperaturetoinvestigatethedifferenceofpropertiesfromlowloadingratetoarelativelyhighloadingrate.Three-pointbendingtestwasusedtostudytheflexuralstrength,strainandmodulusofmicro-surfacingmixture,anduniaxialcompressivetestwascarriedouttoobtaintherelationshipbetweenstrengthandtheloadingrateaswellastemperature.Theexperimentalresultsshowedthatflexuralstrengthathighloadingratewaslargerthanthatatlowloadingrate.Theflexuralstrengthdifferencebetweenlowandhighloadingrateenlargedwhenthetemperaturerose.Theflexuralstrainathighloadingrateincreasedcomparedwithresultsofthelowloadingrate.Resultsoftheflexuralmodulusrevealedthatmicro-surfacingmixtureexhibitedbetteranti-crackingcharacteristicatlowtemperaturewhengivenarelativelylowloadingrate.Resultsofuniaxialcompressivetestrevealedthatthestrengthdifferenceofmicro-surfacingamongdifferentloadingratesincreasedwiththeincreaseoftemperature.Thelogarithmrelationshipbetweenthestrengthandloadingrateoverawiderangeoftemperaturewasobtainedtocomparetheexperimentalandpredictedvalues,whichresultinginareasonableconsistency.
简介:Thispaperfocusesontheeffectoftemperatureontheout-of-planecompressivepropertiesandfailuremechanismofcarbonfiber/epoxycompositepyramidaltrusscoressandwichpanels(CF/CPTSP).CF/CPTSPwithnovelreinforcedframesaremanufacturedbythewaterjetcuttingandinterlockingassemblymethodinthispaper.Thetheoreticalanalysisispresentedtopredicttheout-of-planecompressivestiffnessandstrengthofCF/CPTSPatdifferentambienttemperatures.Thetestsofcompositesandwichpanelsareperformedthroughoutthetemperaturerangefrom-90℃to180℃.Goodagreementisfoundbetweentheoreticalpredictionsandexperimentalmeasurements.ExperimentalresultsindicatethatthelowtemperatureincreasesthecompressivestiffnessandstrengthofCF/CPTSP.However,thehightemperaturecausesthedegradationofthecompressivestiffnessandstrength.Meanwhile,theeffectsoftemperatureonthefailuremodeofcompositesandwichpanelsarealsoobserved.
简介:Thelargesize,crack-freeZr55Cu30Al10Ni5bulkmetallicglass(BMGs)withthediameterof54mmandtheheightof15mmwasbuiltbylasersolidformingadditivemanufacturingtechnology,whosesizeislargerthanthecriticaldiameterbycasting.Themicrostructure,tensileandcompressivedeformationbehaviorsandfracturemorphologyoflasersolidformedZr55Cu30Al10Ni5BMGswereinvestigated.Itisfoundthatthecrystallizationmainlyoccursintheheat-affectedzonesofdepositionlayers,whichconsistofAl5Ni3Zr2,NiZr2,ZrCu,CuZr2phases.Thecontentofamorphousphaseinthedepositisabout63%.Underthecompressiveloading,thedepositpresentsnoplasticitybeforefractureoccurs.Thefractureprocessismainlycontrolledbytheshearstressandthecompressiveshearfractureanglesofabout39.Thecompressivestrengthreaches1452MPa,whichisequivalenttothatofas-CastZr55Cu30Al10Ni5BMGs,andthereexistvein-likepatterns,river-likepatternsandsmoothregionsatthecompressivefractography.Underthetensileloading,thedepositpresentsthebrittlefracturepatternwithoutplasticdeformation.Thefractureprocessexhibitsnormalfracturemodel,andthetensileshearfractureangleofabout90°.Thetensilestrengthisonlyabout609MPa,andthetensilefractographymainlyconsistsofmicro-scaledcoresandvein-likepatterns,dimple-likepatterns,chocolate-likepatternsandsmoothregions.Theresultsfurtherverifiedthefeasibilityandlargepotentialoflaseradditivemanufacturingonfabricationandindustrialapplicationoflarge-scaleBMGsparts.
简介:AdditivelymanufacturedTi-6Al-4Vlatticestructureshavefoundimportantnicheapplications.However,theyoftenshowinsufficientcompressiveductilityorinsufficientstructuralintegrity.Inthisstudy,abatchof45octahedralTi-6Al-4Vlatticestructureswasmanufacturedinthreedifferentstrutdiameters(0.5,1.0,1.5mm)byselectiveelectronbeammelting(SEBM).Theinfluenceofpost-SEBMannealingonthecompressivedeformationcharacteristicsofthelatticestructurewasinvestigated.Theas-builtTi-6AI-4Vlatticesfragmentedwhenthecompressivestrainreached13%-23%dependingonstrutdiameter.Annealingat950℃(Ptransustemperature:995℃)onlyslightlyimprovedthecompressiveductilityofthelatticestructures.However,annealingat1050℃(p-annealing)fundamentallychangedthecompressivedeformationmodeofthelatticestructures.Theresultantcompressivestress-straincurvewasfeaturedbyalongsmoothplateauandnofactureoccurredevenaftersignificantdensificationofthelatticestructurehadtakenplace(>50%ofcompressivestrain).