简介:Aimofpresentworkistoreplaceasbestosinthermalinsulationbyanotherpercentageofnon-toxicfillerssuchassilica.DifferentformulationsoffillerswerepreparedandaddedtoNordel(Tradenameassignedforethylene,propyleneand1,4-hexadieneelastomers).Thephysicalandmechanicalproperties(afterandbeforeaging),andthermalpropertiesofthepreparedsampleswereinvestigated.Theobjectivewastochooseanewformulationwithpropertiesthatresembleascloselyaspossiblethoseoftheoriginallyusedinthermalinsulation.Aftermeasuringthepropertiesoftensilestrength,elongation,hardness,specificgravity,compressionset,reboundresilience,thermalconductivity,andinitialandfinaldecompositiontemperatures,thesamplethathadvaluesveryclosetothoseoftheoriginallyusedinthermalinsulationwaschosenandrecommendedtobeused.FromcomparisonitwasfoundthatEPDMrubberwith50%silicagavetheoptimumpropertiesclosesttotheoriginallyused.
简介:Atime-resolvednumericalcomputationalapproach,involvingthecombustionofdouble-basepropellantisperformedonthermalprotectionmaterialforSRMnozzle.AnimplicitNavier-StokesSolverisselectedtosimulatetwo-dimensionalaxial-symmetricunsteadyturbulentflowofcompressiblefluid.ThegoverningequationsarediscreditedbyusingthefiniteVolumemethod.S-Aturbulencemodelisemployed.CFDschemeisimplementedtoinvestigatethetemperaturedistributioncausesatnozzlethroatinsertscompositematerial.DifferentparametershavebeenselectedfortheanalysistovalidatethetemperaturevariationinthethroatinsertsandbakingmaterialofSRMnozzle.TheadvancedSRMnozzlecompositematerialisalsocharacterizedforthehighthermostabilityandhighthermomechanicalcapabilitiestomakeitmorereliable,simplerandlighter.
简介:2017年7月,公安部等九部门出台《食品、保健食品欺诈和虚假宣传整治方案》,着手严厉打击违规营销宣传产品功效、误导和欺骗消费者等违法行为。2017年9月,公安部等9部门召开全国食品、保健食品欺诈和虚假宣传整治工作电视电话会议,随后多部门联手开展了一次时间跨度最长、涉及范围最广的专项行动。截至2018年7月,全国各地共查处食品、保健食品违法违规案件3.7万余件,货值金额16.2亿元,抓获犯罪嫌疑人8600多名,整治工作取得阶段性成效,市场经营环境得到有效净化。本期特稿以保健品诈骗和虚假宣传为主题,展现了公安部及各地警方在保健食品欺诈和虚假宣传整治工作中取得的成绩,列举了相关典型案例,给出了治理保健品诈骗和虚假宣传的观点,介绍了相关法律法规,总结了防范保健品诈骗和虚假宣传的安全注意事项。