玄武岩纤维布的耐久性试验研究

通过改变玄武岩纤维布、浸润树脂等因素,对玄武岩纤维增强复合材料进行湿热老化试验,系统研究随着老化时间的增长,玄武岩纤维增强复合材料抗拉强度、延伸率和拉伸弹性模量的变化规律,并与其他类型的纤维增强复合材料湿热老化性能进行比较。对玄武岩纤维在结构加固和修复中的应用和耐久性问题有一定指导意义。     

Biomonitoring of urinary metals in a population living in the vicinity of industrial sources: a comparison with the general population of Andalusia, Spain

The Ria of Huelva (south-west Spain) is one of the most polluted fluvial-estuarine systems in the world. Industrial activity delivers huge amounts of pollutants to the local environment, particularly heavy metals and arsenic. Here we aimed to determine urinary levels of As, Cd, Cr, Cu and Ni in a representative sample (n=857) of adults living in the Ria of Huelva. Levels were compared to those from a representative sample of 861 adults of the general urban population of Andalusia (southern Spain) and multiple regression models were developed to identify individual factors associated with urinary levels of these elements. Arsenic levels were significantly higher in the Ria of Huelva as compared to other Andalusian cities, whereas Cd and Ni levels were significantly lower. Despite these differences, levels in both groups were similar to the reference values reported in previous studies for general population. Age, gender, diet and lifestyle were the major factors contributing to the interindividual variation in urinary metals. In conclusion, despite living in a highly polluted area, the population of the Ria of Huelva failed to show higher urinary levels of the studied metals as compared to a reference urban population of the same region.     

Lead levels of edibles grown in contaminated residential soils: a field survey

Plants grown in lead contaminated soils can accumulate lead from the adherence of dust and translocation into the plant tissue. In order to evaluate the potential health hazard due to the consumption of plants grown in residential gardens contaminated by lead, a survey of the lead concentrations in a typical array of edible vegetables, fruits and herbs was conducted. Samples of garden plants harvested from the field were washed with detergent or water alone to remove adhered soil. They were dried, separated into sections including root, shoot and edible fruit, and then analyzed for lead content using inductively coupled plasma-atomic emission spectrometry (ICP-AES). Soil samples, taken in conjunction with the plant harvesting, were analyzed using flame atomic absorbance (FAA). A pattern of lead transference from soil through the root to the stem and leaves of garden crops was found. The majority of the lead was concentrated in the roots (root:soil ranging from 0.02 to 0.51), with some translocation into the shoots (shoot:soil as high as 0.10). This pattern is a concern particularly for crops in which the root, stems, stalks or leaves are edible. The lead concentration in fruiting vegetables was less than the detection limit of 10 ppm (microgram lead/gram dry plant matter). Some edible portions of the leafy vegetables and herbs, however, were found to have lead levels that, if consumed, could contribute to the total body burden of lead. Therefore, urban gardeners should test the lead levels in their soils and develop strategies to ensure safety.     

Performance evaluation of the coupling of a desktop personalized ventilation air terminal device and desk mounted fans

The performance of a coupled system of the Desktop Personalized Ventilation Air Terminal Device (DPV ATD) and desk mounted fans (DMF) was examined in a field environmental chamber. Cooling effect was evaluated using manikin-based equivalent temperature (Teq,), of each of the 26 body segments of a breathing thermal manikin (BTM) and personal exposure effectiveness (PEE) was used as an indicator for effectiveness of ventilation. Computational fluid dynamics (CFD) was used to examine the velocity field generated around BTM to provide better understanding of the relationship between air patterns generated and convective cooling effect on each of the body segments produced by DPV ATD coupled with DMF. Four different positions of DPV ATD were examined: two positions each in front and on the side of the BTM. Measurements were conducted at ambient temperature of 26 °C and PV air temperature of 23 °C at a flow rate of 10 L/s. The results indicate that coupling of DPV ATD and DMF distributes cooling more uniformly across BTM surfaces and therefore has the potential to reduce risk of draft discomfort as compared to usage of DPV ATD alone. Personalized exposure effectiveness was increased in 3 of the positions examined when the coupled system was used.     

WSTi3515S阻燃钛合金热暴露性能

对WSTi3515S合金板坯试样进行550℃/100 h/AC热暴露试验后,分别在室温和100℃下测试其拉伸性能;未经过热暴露的试样,分别在从室温到550℃的不同温度点测试了其拉伸性能。结果表明:经过热暴露后的试样,受到析出相强化的作用,强度略有提高,但塑性指标均存在明显下降,其中,100℃时的拉伸强度低于室温拉伸性能,塑性有所提高,但仍比未经过热暴露的试样测试结果低;热暴露时,晶界处析出第二相是WSTi3515S合金的关键特征,也是WSTi3515S合金热稳定性能降低的原因;在试验温度提高的情况下,光滑拉伸试样强度不断降低,塑性先上升后降低;缺口拉伸试样强度持续下降,塑性没有明显变化,弹性模量持续下降。     

不同地区大气曝晒对涂层耐蚀性能的影响Ⅰ.丙烯酸聚氨酯涂层

通过检测不同大气环境中曝晒后丙烯酸聚氨酯涂层的光泽度、吸水率、涂层／金属间结合强度、涂层的耐盐雾腐蚀性和界面电化学腐蚀特征，研究武汉和拉萨地区大气环境对丙烯酸聚氨酯涂层耐蚀性能的影响。结果表明，丙烯酸聚氨酯涂层在拉萨大气环境中老化程度相对较为严重。在拉萨地区涂层主要以光降解方式老化，而在武汉地区涂层以光降解和水降解方式老化；在拉萨地区，涂层阻挡腐蚀性介质能力下降较为明显，曝晒12个月后涂层的界面电极电化学反应由扩散步骤控制，而在武汉地区该反应主要由电化学步骤控制。     

550℃热暴露对Ti40阻燃钛合金力学性能的影响

对Ti40合金锻态、热处理态、550 ℃热暴露不同时间的组织和性能进行了研究.结果表明,该合金在热暴露过程中析出物较少,并且主要分布在晶界,这些晶界析出物是合金热稳定性能降低的主要原因.通过系统分析合金组织和力学性能,认为可以将Ti40合金550 ℃热暴露过程划分为3个阶段,分别是析出物萌生阶段、析出物长大阶段和析出物在晶界连成析出物带阶段,每个阶段对应的力学性能是由析出物形态决定的.在热暴露末期,出现性能不稳定和硬度与强度不匹配的主要原因是析出物沿晶界形成了完整的析出物带.