The interaction between concrete pavement and corrosion-induced copper runoff from buildings

Changes in chemical speciation of copper and the capacity of concrete pavement to retain copper in runoff water from external buildings have been investigated at urban field conditions, and in parallel laboratory experiments simulating outdoor scenarios. The research study showed the concrete surface to form a copper rich surface layer (≈50 μm thick) upon exposure, and a high capacity to significantly reduce the bioavailable fraction of released copper (20–95%). The retention capacity of copper varied between 5 and 20% during single runoff events in the laboratory, and between 10 and 40% of the total copper release during single natural runoff events. The capacity to retain and reduce the bioavailable fraction of non-retained copper increased with increasing wetness of the concrete surfaces, increasing pH of the runoff water and decreasing flow rates. Bioassay testing with bacterial and yeast bioreporters showed the bioavailable fraction of non-retained copper to be significantly lower than the total copper concentration in the runoff water, between 22 and 40% for bacteria and between 8 and 31% for yeast. The application of generated data to simulate a fictive outdoor scenario, suggests a significant reduction of bioavailable and total copper to background values during environmental entry as a result of dilution, and the interaction with solid surfaces, organic matter and complexing agents already in the drainage system.     

废聚苯乙烯泡沫塑料的催化裂解

为了对废聚苯乙烯泡沫塑料（WPS）资源化利用,通过对WPS进行催化裂解的方法,研究了催化剂种类和裂解温度对裂解时间、裂解油产率、苯乙烯回收率以及裂解油纯度的影响。研究结果表明,催化剂种类和裂解温度对裂解反应有着重要影响。裂解温度升高,裂解油产率提高,裂解时间缩短,但苯乙烯选择性下降;低于380 ℃时,氧化钙的裂解油产率和裂解时间优于氧化铝和氯化铝,但苯乙烯的选择性劣于氧化铝和氯化铝;高于400 ℃时,氯化铝、氧化铝和氧化钙的催化活性接近。在实验条件下,WPS催化裂解的最佳催化剂为氯化铝,380 ℃下的裂解时间为25 min,裂解油产率为85.48%,裂解油中苯乙烯含量为80.66%（w）,且副产物较少。     

An estimate of the contribution of outdoor concrete yards used by livestock to the UK inventories of ammonia, nitrous oxide and methane

Many farms have unroofed concrete yards used by livestock. These concrete yards have received little attention as sources of gaseous emissions. From 1997 to 1999 measurements were made of emissions of ammonia (NH₃), nitrous oxide (N₂O) and methane (CH₄) from 11 concrete yards used by livestock. A postal survey was carried out to assess the areas of yards on farms in England and Wales to enable the measurements to be scaled up to estimate national emissions. Using the results of this study NH₃-N emissions from farm concrete yards were calculated to be ca. 35×10³ t annually. This is 13% of the current estimated total NH₃-N emission from UK livestock. Concrete yards were an insignificant source of N₂O and CH₄ which were both <0.01% of current estimates of agricultural emissions.     

火灾下钢筋混凝土板温度场分布

本文对足尺钢筋混凝土板进行了恒载下受火试验研究,通过试验,了解了钢筋混凝土板在受火过程中的温度分布规律;并与有限元分析结果进行了对照,结果吻合较好。全部火灾试验采用自行研制的火灾试验炉,试验结果表明炉子性能稳定、使用方便。     

空斗墙片墙抗侧力性能试验研究

为了了解空斗墙建筑在地震作用下的抗震性能,通过MTS加载系统对空斗墙片墙的抗侧力性能进行了伪静力试验,研究了不同砌筑方法和不同构造措施下空斗墙片墙在水平和垂直作用下初始裂缝的开展部位、裂缝形态、发展规律和墙体破坏机制,得到了不同空斗墙片墙的开裂荷载和极限荷载,为确定经济有效的空斗墙片墙构造措施提供试验依据.试验结果表明,采用构造柱加拉结筋或采用构造柱加水平钢筋混凝土带的空斗片墙,无论开裂荷载还是极限荷载都较无构造措施的空斗片墙有较大提高,可使空斗墙表现出良好的延性,而无加固措施的空斗墙,其脆性十分明显.     

基于应力强度因子的发动机连杆裂解力数值模拟分析

目的为获得合适的裂解力,以某款轿车发动机连杆为研究对象,应用扩展有限元法(Extended Finite Element Method,XFEM)对裂解工艺中的裂解力进行计算分析。方法根据部件的实际尺寸建立预制初始微裂纹条件下的连杆裂解有限元模型,确定相关的材料参数,并进行有限元网格划分,确定部件之间的约束类型。以应力强度因子大于材料断裂韧度,裂纹即扩展为依据,反复试算得出应力强度因子达到断裂韧度时的裂解力,进而通过大量计算和数据拟合得出初始微裂纹长度与裂解力之间的关系。分析裂解力对塑性区的影响,为裂解力阈值确定给出参考。结果当裂解力能够满足裂解工艺要求时,预制的初始微裂纹长度应尽可能小。结论最为理想的裂解力为材料断裂韧度对应的裂解力。文中提出的分析方法也适合于求解各类连杆的裂解力。     

二氧化碳致裂对煤岩孔隙表面分形特征影响实验研究

为了探究二氧化碳致裂对贵州高瓦斯低渗透煤层的孔隙致裂增透作用,提出了应用低温氮吸附与FHH模型相结合的方法,分析致裂前后煤样的微观孔隙特征变化,并将分形维数与孔隙特征参数结合。研究结果表明:二氧化碳致裂对煤的孔隙具有明显的作用效果,致裂后煤岩体中微孔含量、比表面积减少,而孔容、平均孔直径增加;致裂作用会使煤的分形维数减小,孔隙表面受致裂效果会趋于光滑;受二氧化碳致裂作用,分形维数的大小与平均孔直径、孔容和吸附量等存在负相关关系,与比表面积、微孔含量等呈正相关关系。     

一种新的废塑料油化生产工艺的研究

针对废塑料油化工艺中的问题 ,应用新型的流化床反应釜催化裂解废塑料 ,并利用混合废塑料为原料进行了中试试验 ;研究了催化剂种类和催化改质温度对所得液体油品产率、催化剂积碳率等的影响以及热裂解中裂解温度对液体油品产率的影响。油品经催化改质后 ,其质量得到明显提高 ,该法所生产的汽油和柴油产品符合国家标准     

废弃塑料裂解油化技术

综述了废弃塑料进行热裂解和催化裂解以获得聚合单体、柴油、汽油和燃料气的工艺原理、工艺流程和常用的裂解催化剂。指出裂解油化技术是今后处理废弃塑料的主要方式之一。     

混凝土,砂浆和灰砂砖在模拟酸雨条件下的化学行为

用周期浸泡加速腐蚀试验法研究ｐＨ＝３．５、５．６和ｐＨ为１．０时ＳＯ２－为０、０．０６、０．１、０．２ｍｏｌ／Ｌ等６种模拟酸雨条件下混凝土、砂浆和灰砂砖的化学行为。研究表明：酸雨对材料的影响，主要是Ｈ＋侵蚀引起的溶解腐蚀和ＳＯ４２－侵蚀引起的膨胀腐蚀。