Treatment of gas-phase methanol in conventional biofilters packed with lava rock

The performance of laboratory scale methanol-degrading biofilters packed with lava rock was checked during almost 1 yr under different conditions. The biomass concentration and biomass adaptation of the inoculum dramatically affected the start-up and the performance of the systems during the first stages of operation. A fast start-up was obtained when using concentrated and adapted inocula, while diluted or non-adapted inocula proved to be much less efficient. The performance of the reactor during long-term operation was significantly affected by the toxic load and moisture content of the gas. Critical loads between 120 and 280 g/m(3)h were reached during different phases of the study. The reactor had a high stability to EBRT changes when working at values between 48.0 and 91.1s, showing little or no negative effect when decreasing the EBRT. Hardly any difference was observed regarding performance when using either a downflow or upflow feed, although slightly better results were obtained when working in a downflow mode.     

An extension of ASM2d including pH calculation

This paper presents an extension of the Activated Sludge Model No. 2d (ASM2d) including a chemical model able to calculate the pH value in biological processes. The developed chemical model incorporates the complete set of chemical species affecting the pH value to ASM2d describing non-equilibrium biochemical processes. It considers the system formed by one aqueous phase, in which biochemical processes take place, and one gaseous phase, and is based on the assumptions of instantaneous chemical equilibrium under liquid phase and kinetically governed mass transport between the liquid and gas phase. The ASM2d enlargement comprises the addition of every component affecting the pH value and an ion-balance for the calculation of the pH value and the dissociation species. The significant pH variations observed in a sequencing batch reactor operated for enhanced biological phosphorus removal were used to verify the capability of the extended model for predicting the dynamics of pH jointly with concentrations of acetic acid and phosphate. A pH inhibition function for polyphosphate accumulating bacteria has also been included in the model to simulate the behaviour observed. Experimental data obtained in four different experiments (with different sludge retention time and influent phosphorus concentrations) were accurately reproduced.     

城市环境中的设施与居民的心理和行为

人对环境具有本能的感觉和认知能力,不同环境给予社会群体(指具有一定的文化层次、道德修养、风俗习惯和生活水准等的社会各阶层)的心理感受和行为诱导也各有所异。在当前倡导和谐社会的形势下,构筑良好的城市环境设施,对提高居民的生活环境质量,培养他们健康积极的心理和行为,具有重要的作用和意义。     

Effect of agitation, turbidity, aluminium foil reflectors and container volume on the inactivation efficiency of batch-process solar disinfectors

We report the results of experiments designed to improve the efficacy of the solar disinfection of drinking water, inactivation process. The effects of periodic agitation, covering the rear surface of the container with aluminium foil, container volume and turbidity on the solar inactivation kinetics of Escherichia coli (starting population = 10(6) CFU ml(-1)) were investigated. It was shown that agitation promoted the release of dissolved oxygen from water with subsequent decrease in the inactivation rates of E. coli. In contrast, covering the rear surface of the solar disinfection container with aluminium foil improved the inactivation efficiency of the system. The mean decay constant for bacterial populations in foil-backed bottles was found to be a factor of 1.85 (std. dev. = 0.43) higher than that of non-foil-backed bottles. Inactivation rates decrease as turbidity increases. However, total inactivation was achievable in 300 NTU samples within 8 h exposure to strong sunshine. Inactivation kinetics was not dependent on the volume of the water container for volumes in the range 500-1500 ml.     

半刚性基层沥青路面的裂缝形成机理与预防

阐述半刚性基层沥青路面的裂缝形式、裂缝形成机理及影响裂缝频数的主要因素，并提出了预防裂缝的措施。     

韩国新乡村运动

韩国新乡村运动是一场由韩国政府主导调整经济结构的战略性全民运动。其特点是通过实实在在的项目开发,激发广大农民改变旧貌的热情,让农民在新村运动中受惠,从中探索出一条扶贫、致富的道路。免费向各村提供300袋水泥,是韩国政府打响新乡村运动的“第一炮”,茅草屋变砖瓦房,油灯变电灯,则是韩国乡村面貌变化的第二步,而优化农业结构,增加农民收入,是韩国新乡村运动的核心。期间,一首《致富歌》唱遍韩国乡村“清晨的曙光照亮,让我们振作精神,走向致富的前方。拼搏、奋斗,我们的前程充满辉煌。”深究中韩两国经济发展的历史与现状就会发现,韩国在推进和实现国家工业化、城市化和现代化进程中,遇到的诸多问题与中国目前遇到的问题多有相似之处。因此,我们相信韩国新乡村运动的经验、教训对中国调整农村政策和产业结构、对中国三农问题的解决都会有所启示。我们更相信,中国农民的前程也一样充满阳光。     

用陶瓷复合材料的概念设计人工骨生物材料

现有人工骨陶瓷材料存在的主要缺点是脆性大,抗疲劳性差。由于生物陶瓷材料的弹性模量较小,很难采用添加氧化锆引起的相变增韧来解决上述缺点。采用添加纤维制成陶瓷纤维复合材料,并控制基质相中的气孔率分布呈梯度倾斜,是一个合理而有前途的新颖人工骨材料。     

离子型火灾探测器的清洗工作值得关注

目前在我国使用的火灾自动报警系统中 ,各种探测器品种繁多 ,但应用最广的是离子型火灾探测器。离子型火灾探测器的工作原理是利用空气离化法 ,当α射线通过两个电极之间的空气时 ,由于α射线的作用 ,不导电的空气分子变成了导电的正、负离子。在电场的作用下 ,负离子向正极运动 ,正离子向负极运动 ,并产生感应电荷。然后将感应电荷所形成的电流或电压信号 ,经过电子电路的整形、放大、甄别等过程而被分析和记录。当烟雾粒子进入电离室后 ,使电离电流减少 ,这样 ,就将烟雾的物理量转变成电量 ,发出火灾报警信号 ,达到了火灾报警的目的。一、…     

钢结构旧厂横向刚度的实测计算及其可靠性鉴定标准的探讨

在《工业厂房可靠性鉴定标准》中，如何按空间图形评定厂房的横向刚度，尚缺乏标准。在太钢第一炼钢厂平炉车间抽柱钢厂房的可靠性鉴定中，采用按空间工作的实测法和空间计算模式的有限元分析进行了评定，并根据研究结果提出了建议标准     

论建筑的同一性和多样性

西方建筑发展历程充满了复杂性和矛盾性，而造成这种现象的主要原因就是因为它们的建筑设计思想缺乏本质同一性的统摄。