NF E37-306-2005 往复式内燃机交流发电机组.第6部分:试验方法

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标准名称：	口琴
中标分类：	轻工、文化与生活用品 >> 文教、体育、娱乐用品 >> 乐器
发布日期：
实施日期：	1991-01-01
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【英文标准名称】:StandardPracticeforEvaluatingthePerformanceofDiffusiveSamplers
【原文标准名称】:评价扩散采样器性能的标准实施规程
【标准号】:ASTMD6246-2008
【标准状态】:现行
【国别】:美国
【发布日期】:2008-01-01
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:D22.04
【标准类型】:(Practice)
【标准水平】:()
【中文主题词】:
【英文主题词】:accuracy;airmonitoring;bias;concentration;diffusive;evaluation;gases;passive;performance;precision;samplingandanalysis;samplers;tests;uncertainty;vapors;workplaceatmospheres;Airmonitoring;Concentration(ofelements);
【摘要】:Gasorvaporsamplingisoftenaccomplishedbyactivelypumpingairthroughacollectionmediumsuchasactivatedcharcoal.Problemsassociatedwithapumpx2013;inconvenience,inaccuracy,andexpensex2013;areinextricablefromthistypeofsampling.Thealternativecoveredbythispracticeistousediffusionformovingthecompoundofinterestontothecollectionmedium.Thisapproachtosamplingisattractivebecauseoftheconvenienceofuseandlowtotalmonitoringcost.However,previousstudieshavefoundsignificantproblemswiththeaccuracyofsomesamplers.Therefore,althoughdiffusivesamplersmayprovideaplethoraofdata,inaccuraciesandmisuseofdiffusivesamplersmayyetaffectresearchstudies.Furthermore,workerprotectionsmaybebasedonfaultyassumptions.Theaimofthispracticeistocountertheuncertaintiesindiffusivesamplingthroughachievingabroadlyacceptedsetofperformancetestsandacceptancecriteriaforprovingtheefficacyofanygivendiffusivesamplerintendedforuse.1.1Thispracticecoverstheevaluationoftheperformanceofdiffusivesamplersofgasesandvaporsforuseoversamplingperiodsfrom4to12handforwindspeedslessthan0.5m/s.Suchsamplingperiodsandwindspeedsarethemostcommonintheindoorworkplacesetting.Thispracticedoesnotapplytostaticorareasamplinginwindspeedslessthan0.1m/s,whendiffusionoutsidethesamplermaydominateneededconvectionfromtheambientairtothevicinityofthesampler.Givenasuitableexposurechamber,thepracticecanbeextendedtocoversampleruseforothersamplingperiodsandconditions.Theaimistoprovideaconcisesetofexperimentsforclassifyingsamplersprimarilyinaccordancewithasinglesampleraccuracyfigure.Accuracyisdefined(3.2.1)inthisstandardsoastotakeintoaccountbothimprecisionanduncorrectedbias.Accuracyestimatesrefertoconditionsofsamplerusewhicharenormallyexpectedinaworkplacesetting.Theseconditionsmaybecharacterizedbythetemperature,atmosphericpressure,humidity,andambientwindspeed,noneofwhichmaybeconstantoraccuratelyknownwhenthesamplerisusedinthefield.Futhermore,theaccuracyaccountsfortheeffectsofdiffusivelossofanalyteontheestimationoftime-weightedaveragesofconcentrationswhichmaynotbeconstantintime.Asidefromaccuracy,thesamplersaretestedforcompliancewiththemanufacturer''sstatedlimitsoncapacity,possiblyinthepresenceofinterferingcompounds.1.2Thispracticeisanextensionofpreviousresearchondiffusivesamplers(1-14)aswellasPracticesD4597,D4598,D4599,andMDHS27.Anessentialadvancehereistheestimationofsampleraccuracyunderactualconditionsofuse.Futhermore,thecostsofsamplerevaluationarereduced.1.3Knowledgegainedfromsimilaranalytesexpeditessamplerevaluation.Forexample,interpolationofdatacharacterizingthesamplingofanalytesatseparatedpointsofahomologousseriesofcompoundsisrecommended.Atpresenttheprocedureof(9)issuggested.Followingevaluationofasamplerinuseatasinglehomologousseriesmemberaccordingtothepresentpractice,highermolecularweightmemberswouldreceivepartialvalidationsconsideringsamplingrate,capacity,analyticalrecovery,andinterferences.Thetestfordiffusiveanalytelosscanbeomittediftheeffectisfoundnegligibleforagivensampleroranalyteseries.1.4ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.5Thisstandarddoesnotpurportt......
【中国标准分类号】:C70
【国际标准分类号】:13_040_30
【页数】:8P.;A4
【正文语种】:英语