简介:Thestudyofbed-loadtransportisofgreatsignificancebothintheoryandinpractice.Thispaperdiscussesthesaltationofbed-loadsolidgrainsinflowingwater.Experimentsandtheoreticanalysishavebeenmadebymeansofhigh-speedphotographingandadvanceddataprocessingtechniquewithacombinedmethodbasedonmechanicalandstatisticaltheories.Itindicatesthatthesaltationisthemainformofthebed-loadtransportunderordinaryflowingconditions.Inthemeantime,takingsuecessivesaltationasthemod-elofbed-loadtransport,systematicanalysishasbeenmadewithregardtothekinematicpropertiesandmechanismofsaltation.ThestatisticalanalysisshowsthattheprobabilitydensityfunctionsoftherelativeheightandlengthofsaltationareinconformitywithΓ-typedistribution,whiletheprobabilitydensityfunc-tionsoftherelativevelocitiesofsaltationareinconformitywiththeGaussiandistribution.
简介:Determinationofsedimentstabilityinthefieldischallengingbecausebedshearstress(BSS),adeterminingfactorofsedimenterosion,can’teasilybedirectlymeasured.Totacklethischallengeandreliablyassesssedimenterodibilityinafastflowingriver,astandaloneunderwatercamerasystemandanewinsituflume(ISF)weredevelopedandappliedinthisstudy.ThecamerasystemwasusedtorecordsedimentmovementandthenewISFwasusedformeasuringcriticalbottomshearstress(CBSS).Thecameracanbedeployedaloneinwatertorecordvideosortakepictureswithlightemittingdiode(LED)lightingandflexibleschedulesettings.TheISFisbasedontheconceptthattheamountofforceneededtoerodethesameparticleunderdifferentflowconditionsshouldbesimilar.TwohighresolutionAcousticDopplerCurrentProfilers(ADCP)alsoweredeployedinthefieldtocollectvelocity-depthprofileswhichareusedbyconventionalmethodstocalculateBSSwiththelawofthewall.ThesedimenterodibilitywasthenassessedbasedonthecomparisonbetweentheobtainedCBSSandBSSandthenfurtherverifiedwiththerecordedobservationsfromthedeployedcamera.Theresultsrevealthatthewidelyusedconventionalmethodcanproducelargeuncertaintiesandisnotadequatetoprovidemeaningfulconclusionundertheseconditions.
简介:Inthispaper,animprovementofheatingmethodformeasuringwetnessoftheflowingwetsteamisdeveloped,thebasicprincipleoftheheatingmethodispresentedandthemathematicalmodelhasbeenbuiltforanalyzingthethermodynamicsproblemsduringtheprocessofheating,Moreover,aninstrumentformeasuringwetnessofwetsteamflowwasdesignedandmadeout.ThisinstumenthasbeenusedformeasuringwetnessofthewetsteamflowattheoutletofthenozzleriginThermalTurbineLaboratory,Xi'anJiaotongUniversity,Byanalyzingtherelativeerroroftheresult,itwasfoundthatthisinstrumenthasfairlyhighaccuracy,itcanbeusedastheprototypeofpracticalinstrumentandhasanimportantapplicablevalueinengineering.
简介:StudyofthemajorAsianriversdischargetotheoceanrevealsvariationsoftheirwaterdischargesandsedimentloads,andlocalcharacteristicsofriversedimentconcentrations.Onthebasisofthis,theAsianriversfallintothreeregions,includingEurasiaArctic,EastAsia,SoutheastandSouthAsiaRegions.TheEurasiaArcticRegionischaracterizedbythelowestsedimentconcentrationandload,whiletheEastAsiaRegionisofthehighestsedimentconcentrationandhighersedimentload,andtheSouth-EastandSouthAsiaRegionyieldshighersedimentconcentrationandhighestsedimentload.Thesedimentloadsoftheseregionsaremainlycontrolledbyclimate,geomorphologyandtectonicactivity.TheEurasiaArcticriverswithlargebasinareasandwaterdischarge,drainlowreliefwhichconsistsoftundrasediment,thuscausingthelowestsedimentload.TheEastAsiariverswithsmallbasinareasandlowestwaterdischarges,drainextensiveloessplateau,andtransportmosterodibleloessmaterial,whichresultsinhighestsedimentconcentration.TheSEandSouthAsiariversoriginatingfromtheTibetPlateauhavelargebasinareasandthelargestwaterdischargesbecauseoftheSummerMonsoonandhighrainfallinfluence,causingthehighestsedimentload.InAsia,tectonicmotionoftheTibetPlateauplaysanimportantrole.ThoselargeriversoriginatingfromtheTibetPlateautransportabout50%oftheworldriversedimentloadtooceanannually,forminglargeestuariesanddeltas,andconsequentlyexertingagreatinfluenceonsedimentationinthecoastalzoneandshelves.
简介:Thestructuralpropertiesofwateratdifferenttemperatureshavebeeninestigatedusingaflexiblewatermodelintheisothermal-isobaricensemble.Withdecreasingtemperature,thetetrahedralityofthedistributionofthewatermoleculesaroundthecentralwatermoleculeisenhanced,andthehydrogenbondsbecomemorelinear.Bymeansofaconjugategradientenergyminimization,dynamicalconfigurationsatvarioustemperatureshavebeenmappedontonearbypotential-energyminima,the50°-60°peak(P1)inthedistributionfunctionoftheO-O-Oangleofatrimerbecomesfarsmaller.HoweverthereappearstobeasmallbutobservabletemperaturedependenceofP1,i.e.thehigherthetemperature,thehighertheP1intensity.
简介:Withthedevelopmentofscienceandtechnology,theresearchesandapplicationofwaterresourcesincludingthegaswaterhavebeenconstantlydeveloped.Throughananalysisontheflawsofthewaterrighttheory,andbyexecutingreconstructionandrenewalofthetheoryandsystemofwaterrightinmodernsociety,thewaterrightpositionofthegaswaterwillbeestab-lished,leadingtothematurityofthewholelaweffectivenessandsubstantialresultsofwaterright.
简介:AwaterbearerinIndiahadtwolargepots,eachhungoneachendofapolewhichhecarriedacrosshisneck.Oneofthepotshadacrackinit,whiletheotherpotwasperfectandalwaysdeliveredafullportionofwaterattheendofthelongwalkfromthestreamtothemaster'shouse,andthecrackedpotwasonlyhalffullwhenthewaterbearerarrived.Fortwoyearsthiswentondaily.Ofcourse,theperfectpotwasproudofitsperfectiontowhichitwasbrought.Butthepoorcrackedpotwasashamedof...