A general mechanistic model for predicting the fate and transport of phthalates in indoor environments

A mechanistic model that considers particle dynamics and their effects on surface emissions and sorptions was developed to predict the fate and transport of phthalates in indoor environments. A controlled case study was conducted in a test house to evaluate the model. The model‐predicted evolving concentrations of benzyl butyl phthalate in indoor air and settled dust and on interior surfaces are in good agreement with measurements. Sensitivity analysis was performed to quantify the effects of parameter uncertainties on model predictions. The model was then applied to a typical residential environment to investigate the fate of di‐2‐ethylhexyl phthalate (DEHP) and the factors that affect its transport. The predicted steady‐state DEHP concentrations were 0.14 μg/m³ in indoor air and ranged from 80 to 46 000 μg/g in settled dust on various surfaces, which are generally consistent with the measurements of previous studies in homes in different countries. An increase in the mass concentration of indoor particles may significantly enhance DEHP emission and its concentrations in air and on surfaces, whereas increasing ventilation has only a limited effect in reducing DEHP in indoor air. The influence of cleaning activities on reducing DEHP concentration in indoor air and on interior surfaces was quantified, and the results showed that DEHP exposure can be reduced by frequent and effective cleaning activities and the removal of existing sources, though it may take a relatively long period of time for the levels to drop significantly. Finally, the model was adjusted to identify the relative contributions of gaseous sorption and particulate‐bound deposition to the overall uptake of semi‐volatile organic compounds (SVOCs) by indoor surfaces as functions of time and the octanol‐air partition coefficient (K_oa) of the chemical. Overall, the model clarifies the mechanisms that govern the emission of phthalates and the subsequent interactions among air, suspended particles, settled dust, and interior surfaces. This model can be easily extended to incorporate additional indoor source materials/products, sorption surfaces, particle sources, and room spaces. It can also be modified to predict the fate and transport of other SVOCs, such as phthalate‐alternative plasticizers, flame retardants, and biocides, and serves to improve our understanding of human exposure to SVOCs in indoor environments.     

A PROBABILISTIC ASSESSMENT OF TEMPERATURE EFFECTS ON THE LOW CYCLE FATIGUE BEHAVIOUR OF 1Cr_(18)Ni_9Ti STEEL WELD METAL

1.IntroductionFatigueistakenasapotentialfailuremodeintheRulesforConstructionofNuclearPowerPlantComponentsofASMESectionill[1].ThedesignS-NcurveisdevelopedfirstlybyusingtheLangerS--Nmodel[21fittingthedataofvirtualstressamplitudeandcyclestocrackinitiation,whichareobtainedfromuniaxialstrain-controlledtestonsmall-sizepolishedbarspecimensinairenvironment,toobtainameanbest--fitcurve.Next,twotypesofcorrection,ameanstresscorrectionandatemperaturecorrection,areappliedtothemeancurve.Then,thedataar…     

Corrosion Process and Surface Protection for YBCO Superconductor

１ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅＹＢＣＯｓｕｐｅｒｃｏｎｄｕｃｔｏｒｒｅａｃｔｓｖｅｒｙｅａｓｉｌｙｗｉｔｈｍｏｉｓｔｕｒｅａｎｄｃａｒｂｏｎｄｉｏｘｉｄｅｉｎｔｈｅａｉｒｔｏｆｏｒｍａｌｋａｌｉ．Ｔｈｉｓｒｅｄｕｃｅｓｔｈｅｓｕｐｅｒｃｏｎｄｕ...     

辅助加热PCVD—TiN薄膜的性能及结构分析

研究了反应气体对辅助加热ＰＣＶＤ－ＴｉＮ薄膜制备的影响。结果表明,提高反应气体中ＴｉＣｌ４薄膜内的氯含本不变。     

Q235钢奥氏体氮碳共渗后的回火转变

研究了Ｑ２３５钢奥氏体氮碳共渗后共渗层回火时组织、结构、表面硬度、硬度分布以及耐磨性的变化。结果表明：奥氏体氮碳共渗层在回火后,化合物层的ε相析出γ相,奥氏体淬火层发生含氮马氏体的分解和残留奥氏体的转变,过渡层也析出了γ相,从而使共渗层的表面硬度和渗层中各层的硬度都得到很大的提高,硬度分布得到改善,同时使渗层的耐磨性提高,得到了更为优越的渗层     

重力分离SHS法内衬陶瓷层中裂纹形成机理的研究

基于重力分离ＳＨＳ法制备陶瓷内衬复合钢管的研究,探讨了内衬陶瓷层中的裂纹形成机理,并分析了影响裂纹萌生与扩展的因素。研究表明,内衬陶瓷层中主要分布着由压应力场所造成的径向裂纹和因热应力场所引起的网状裂纹;陶瓷层中裂纹的萌生与扩展,除决定于应力场强度外,还受陶瓷层中的气相孔隙及Ｆｅ粒子尺寸分布的影响。     

铝电磁铸轧冷却区中电磁场行为探讨

介绍了铝电磁连续铸轧冷却区中电磁场的基本特性,探讨了电磁场在冷却区段的作用效果,分析了电磁场在该区中产生的几种磁势和电势,以及这几种磁势和电势的形态对铝熔体的影响,并描述了铝熔体中电子在这个区域的运动轨迹。     

泡沫金属的研究及其应用进展

详细介绍了新型结构功能材料－泡沫金属的制备方法,并针对其性能特征和结构敏感性叙述了泡沫金属的各种优异特性和应用领域,指出了泡沫金属材料是一种具有广阔应用前景的新型结构功能材料。     

石油天然气工业中CO2腐蚀的研究进展

介绍了石油天然气工业中ＣＯ２腐蚀方面的研究进展,其中包括ＣＯ２的腐蚀机制、腐蚀速率计算公式、影响腐蚀的各种因素及腐蚀控制手段,重点介绍了影响腐蚀速率的各种因素。     

预制块制备对挤压铸造SiCW／ZM5复合材料性能的影响

制备了含不同粘结剂的ＳｉＣ晶须预制块,并采用挤压铸造法制备出含不同粘结剂的ＳｉＣｗ／ＺＭ５镁基复合材料,对其组织结构和力学性能进行了研究。结果表明,采用含酸性磷酸铝粘结剂制备的ＳｉＣｗ／ＺＭ５镁基复合材料的性能最佳,这可能和粘结剂与晶须以及基体合金的界面反应有关