塑料管道行业洗牌在即

近年来,国家化学建材领导小组相继出台了“关于加强我国化学建材生产和推广应用的若干意见”、“国家化学建材产业十五计划和2010年发展规划纲要”和“关于加速化学建材推广应用和限制淘汰落后产品的规定”等政策,这些政策大大加强了塑料建材的推广应用力度。在塑料管道行业发展前景一片光明而欣喜的同时,我们也不得不注意到这样一个情况,无论从市场需求还是资金的市场运作来看,塑料管道企业区域化、集团化形式已凸显出来。由于现阶段我国塑料管道产业集中度偏低,导致很多企业工艺装备小型化、科技水平低,造成产品缺乏竞争力,产品结构不合理…     

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.     

工业废料磷石膏的工程特性试验研究

对大量作为工业废料堆放的磷石膏进行材料试验，即级配试验、击实试验、三轴试验和压缩试验，研究其压缩特性和强度特性及影响其力学性能的因素，探讨了其作为地基处理时的换填材料的可行性。     

Elimination of beta-blockers in sewage treatment plants

beta-Blockers are used to treat high blood pressure as well as patients recovering from heart attacks. In several studies, they were detected in surface water, thus indicating incomplete degradability of these substances in sewage treatment plants (STPs). In this study, we determined the sorption coefficients (K(D)) and degradation rates of the four beta-blockers sotalol, atenolol, metoprolol and propranolol in sludge from an STP operating with municipal wastewater. The sorption coefficients (K(D), standard deviations in brackets) were determined as 0.04(+/-0.035), 0.04(+/-0.033), 0.00(+/-0.023) and 0.32(+/-0.058) Lg(-1)(COD), and the pseudo-first-order degradation rate constants were estimated to be 0.29(+/-0.02), 0.69(+/-0.05), 0.58(+/-0.05) and 0.39(+/-0.07) Ld(-1)g(-1)(COD) for sotalol, atenolol, metoprolol and propranolol, respectively. These values translate into a typical elimination in STPs (sludge concentrations of 4g(COD)L(-1) and a hydraulic retention time of 6h) of 25%, 37%, 44% and 50% for sotalol, propranolol, metoprolol and atenolol, respectively. These results are also confirmed by measurements in two municipal STPs for atenolol, sotalol and propranolol. The estimated eliminations are slightly too high for metoprolol.     

Reproducibility of indoor environment characteristics obtained in a walk through questionnaire. A pilot study

Walk through questionnaires may be feasible tools to obtain data on the indoor environment in community studies. However, limited information is available regarding the reproducibility of the data obtained through these questionnaires. In this pilot study, two construction engineering students inspected ten dwellings twice by means of a standardized walk through questionnaire. The two engineering students inspected the dwellings independent of each other within two months. Time between the two visits varied between 14 and 40 days. The variables presented were based on information from the residents and inspection. The continuous variables recorded included number of rooms in the dwellings, room volume, length of filled shelves and textile area. The inter- and intra-observed variabilities were poorer for number of rooms and shelf factor than for the other variables. For the 3 of the 9 categorical variables based on inspection, the inter-observer comparison showed complete agreement with a kappa statistics of 1.0, these variables being condition of the window frames and construction of outside walls and roof. One of the categorical variables showed a kappa statistics of < 0.5, these variables being presence of basement and presence of condensation at windows. This study indicates a wide variation in observer variability between various items of a walk through questionnaire. Clear definitions of all the parts of the questionnaire are needed, as well as thorough training of observers.     

Landscape, race and memory: biographical mapping of the routes of British Asian landscape values

In this paper the migration routes of British Asian women living in London are examined. It is shown that British Asians connect with a myriad of landscapes abroad, including East Africa, India and Pakistan. These connections to past landscapes are mapped and considered here as valued environments of British Asian women in Britain. Through the mapping of their biographies, it is apparent that memories of other landscapes are embedded in environmental practices in Britain, therefore contributing to making the landscape in Britain inclusive and meaningful in the context of the South Asian migration. The maps of migration show the heterogeneity of landscapes experienced by the British Asian women. Memories of other lands manifest themselves in the UK. The effect of these memories on the South Asian home itself in the process of shaping diasporic geographies of belonging and being within the UK is illustrated.     

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、…     

Indoor air quality in the 21st century: search for excellence

Field studies demonstrate that there are substantial numbers of dissatisfied people in many buildings, among them those suffering from sick building syndrome (SBS) symptoms, even though existing standards and guidelines are met. The reason is that the requirements specified in these standards are rather low, allowing a substantial group of people to become dissatisfied and to be adversely affected. A paradigm shift from rather mediocre to excellent indoor environments is foreseen in the 21st century. Based on existing information and on new research results, five principles are suggested as elements behind a new philosophy of excellence: 1) better indoor air quality increases productivity and decreases SBS symptoms; 2) unnecessary indoor pollution sources should be avoided; 3) the air should be served cool and dry to the occupants; 4) "personalized air", i.e. a small amount of clean air, should be served gently, close to the breathing zone of each individual; and 5) individual control of the thermal environment should be provided. These principles of excellence are compatible with energy efficiency and sustainability.     

Semi-volatile organic compounds in the Campaspe River system (Victoria, Australia)

The levels of semi-volatile organic compounds (SVOCs) in the Campaspe River system, North Central Victoria, Australia, were monitored from January to September 1995, and the environmental trends and sources of these compounds were determined. The land use within particular catchments dictated the complexity of the SVOCs in run-off water. Run-off from native forest contained the greatest number of SVOCs. Soil and ground litter were shown to contain the greatest complexity of SVOCs, mostly terpenes. However, only a small proportion were leached by run-off with the remainder being tightly bound to the soil or volatilizing to the atmosphere. Under the prevailing drought of early 1995, the rivers contained no detectable SVOCs until the first catchment run-off after significant rainfall in May. The maximum complexity and concentration of the SVOCs coincided with extensive run-off after heavy rainfall in June, effecting a surge of SVOCs with the flood peak. Fatty acids, their amides and hydrocarbons made up the majority of the compounds identified and were in the 1-39 micrograms/l concentration range. The levels then diminished as the catchment was flushed by continual run-off. These results support Lake's 1967 hypothesis that natural floodwaters contain a signature of SVOCs entering from the catchment. The downstream passage of these compounds was obstructed by a man-made storage, Lake Eppalock, with only low concentrations of SVOCs (1-3 micrograms/l) in the outflow, displaying no correlation to run-off.