不同泥龄对活性污泥絮凝特性的影响

为了揭示不同污泥龄活性污泥的絮凝特性及作用机制,采用序批式反应器,考察污泥龄（solid retention time,SRT）对絮体EPS（extra-micro colony polymeric substances,EMPS）和菌胶团EPS（extra-cellular polymeric substances,ECPS）2种EPS组分的影响,通过扩展的DLVO理论和EPS组分解析不同污泥龄的絮凝性能。研究结果表明,随着SRT的增大,活性污泥的相互作用能曲线存在明显的势垒和势垒值逐渐减少,EMPS和ECPS含量逐渐减少,且相对于ECPS的变化,EMPS含量随泥龄的变化更加明显,其中蛋白质与腐殖质含量逐渐降低,污泥絮凝性能变好。这表明,较高的污泥相互作用能势垒和EMPS组分含量是污泥絮凝性能低的内在机制,且EMPS中蛋白质和腐殖质含量的变化是不同污泥龄污泥絮凝性能差异的主要原因。     

厌氧氨氧化工艺的启动及微生物群落结构分析

构建了2个装载不同填料的厌氧污泥床（UASB）反应器（R1：载活性炭的K3填料;R2：普通K3填料）,对比研究了2种厌氧氨氧化系统的启动特征、脱氮性能,分析了R1反应器的微生物群落结构变化规律,并对R1不同高程的基质去除特征和微生物群落组分进行了解析。结果发现,R1在第86天启动成功,短于R2的100 d,长期运行后R1和R2的最大氮容积负荷（NLR）分别为2.156和2.122 g·（L·d）-1,最大氮去除负荷（NRR）分别达到1.855和1.815 g·（L·d）-1。在R1中,内部基质浓度随高度增加而降低,进水NH4+-N浓度较低时（50、100 mg·L-1）和较高时（350、450 mg·L-1）,基质的去除分别集中在反应器高度0~7 cm和17~37 cm处,而且厌氧氨氧化菌含量与氮去除率间呈正相关关系。另外,R1运行过程中厌氧氨氧化优势菌种由Candidatus brocadia（20 d）变为Candidatus Jettenia和Candidatus Kuenenia的混合菌种（134 d）。     

多因素对聚氯乙烯和废弃液晶显示屏协同热解氯化提铟的影响

聚氯乙烯（polyvinyl chloride, PVC）和废弃液晶显示屏（liquid crystal displays, LCDs）协同热解,可利用PVC产生的氯化氢提取LCDs中的铟,实现废弃PVC塑料和LCDs废物综合利用。通过PVC和LCDs协同热解实验,在PVC热解温度和载气流速一定条件下,采用采用Design-Expert 8.0.5b软件对氯铟比、氯化温度、氯化时间等因素进行实验方案设计和结果分析。结果表明,在其他操作条件一定的前提下,氯铟比、氯化温度、氯化时间对铟回收率的影响均为显著;通过分析实验结果并建立数学模型,最终得到实际可操作的最佳实验条件,其结果为氯化温度为500 ℃、氯化时间为30 min和氯铟比为11：1,铟回收率为97.50%。本研究对于废弃PVC塑料和LCDs的资源化综合利用具有重要的参考价值。     

构建限制性条件下微生物群体生长模型时的问题

Logistic生长模型在表征营养限制性生长条件下微生物群体生长时,遇到了种种困难．该模型未能明确给出微生物群体生长的“延迟期”和“代时”两个重要生长动力学参数,也忽视了方程中参数“r”应为平均生长速率,且不具有内禀生长率性质等诸多生物学特点．采用E．coli ATCC31343,37℃液体摇瓶培养下获得的实验数据,证实了Logistic模型存在的上述局限性．通过对E．coli以葡萄糖和山梨醇共作碳源时,表现出的“二峰生长”曲线与用Logistic方程拟合结果的比较,表明适合度分析（goodness—fit test）不能作为模型是否适合的唯一判据．并对构建微生物群体生长模型的策略进行了讨论．图5参31     

我国注册安全工程师注册现状分析

根据注册安全工程师初始注册申请表以及注册安全工程师注册信息管理数据库、国家安全生产监督管理总局和人事部人事考试中心提供的数据,对目前已注册的17441名注册安全工程师的年龄结构、学历结构、安全生产相关工作年限和受聘单位性质进行了统计分析。结果表明,我国现有注册安全工程师年龄、学历结构合理,但数量上仍不能满足需要。笔者提出应通过制订考试标准等方式加快注册安全工程师专业技术人才队伍建设的建议。     

基于关联维的事故时间序列分形特征分析

根据我国"十五"期间事故统计数据,构造了一个事故时间序列;基于相空间重构理论,对事故序列进行了相空间重构,应用G-P算法,对事故时间序列的分形特征进行了研究,计算得出事故时间序列的关联维数。研究结果表明:当嵌入维数达到8以后,该事故动力学系统具有稳定的关联维数4.7,说明至少有5个因子在影响着事故时间序列的动态变化,并且该系统的有效自由度为8。本研究对建立事故时间序列的预测模型有较大的参考价值。     

Measuring mining safety with injury statistics: lost workdays as indicators of risk

PROBLEM: Mining in the United States remains one of the most hazardous industries, despite significant reductions in fatal injury rates over the last century. Coal mine fatality rates, for example, have dropped almost a thousand-fold since their peak in 1908. While incidence rates are very important indicators, lost worktime measures offer an alternative metric for evaluating job safety and health performance. The first objective of this study examined the distributions and summary statistics of all injuries reported to the Mine Safety and Health Administration from 1983 through 2004. Over the period studied (1983-2004), there were 31,515,368 lost workdays associated with mining injuries, for an equivalent of 5,700 person-years lost annually. The second objective addressed the problem of comparing safety program performance in mines for situations where denominator data were lacking. By examining the consequences of injuries, comparisons can be made between disparate operations without the need for denominators. Total risk in the form of lost workday sums can help to distinguish between lower- and higher-risk operations or time periods. METHOD: Our method was to use a beta distribution to model the losses and to compare underground coal mining to underground metal/nonmetal mining from 2000 to 2004. RESULTS: Our results showed the probability of an injury having 10 or more lost workdays was 0.52 for coal mine cases versus 0.35 for metal/nonmetal mine cases. In addition, a comparison of injuries involving continuous mining machines over 2001-2002 versus 2003-2004 showed that the ratio of average losses in the later period to those in the earlier period was approximately 1.08, suggesting increasing risks for such operations. DISCUSSION: This denominator-free safety measure will help the mining industry more effectively identify higher-risk operations and more realistically evaluate their safety improvement programs. IMPACT ON INDUSTRY: Attention to a variety of metrics concerning the performance of a job safety and health program will enhance industry's ability to manage these programs and reduce risk.     

Carbon market and technology transfer: statistical analysis for exploring implications

The impact of clean development mechanism (CDM) projects on climate change technology transfer (CCTT), which is essential for developing countries to achieve higher mitigation targets and move towards more sustainable paths, has been, until now, inadequately understood and analysed. The aim of this paper is to analyse the carbon market contribution to CCTT, mainly through the CDM, so as to stimulate developing countries towards the deployment and diffusion of low-carbon technologies that fulfil their sustainability goals. Indeed, relatively few studies deal with the assessment of the CDM contribution to CCTT, mainly through desk analysis and empirical evaluations on project design documents. To the best of our knowledge, there are no studies dealing with CCTT through CDM projects using statistical approaches. The added value of this article is the use of statistical analysis, time series analysis and multiple linear regression to analyse carbon market experiences in selected cross-representative developing countries. This assessment indicated the very heterogeneous CCTT across CDM project types, varying significantly in terms of reliance on imported technology, mix of equipment and knowledge and source countries for the technology.     

Analysis of herbicide residues by gas chromatography

The extraction and clean‐up, and gas Chromatographic conditions for the detection and determination of herbicides, their metabolites and related compounds are reviewed. The literature material is examined critically in the text and presented in tabular form for quick reference. The section dealing with extraction/clean‐up techniques is sub‐divided with respect to water, soil, plant material, animal, fish and micro‐organisms. Under eight herbicide group headings the important gas Chromatographic parameters such as stationary phase, support phase, column temperature and mode of detection are tabulated. Also tabulated are the application of various detectors to herbicide analyses and limits of detection where information was available. Most commonly used liquid and support phases are listed and their frequency of use given. Different aspects of derivative formation used for the positive identification and quantitation of herbicides are discussed with emphasis on esterification, alkylation and silylation. Other important conversion techniques are outlined, particularly those associated with enhancement of sensitivity e.g. bromination, iodination, dinitrophenylation etc. Efforts that have been made towards general and automated analytical methods are discussed.     

Toxic effects of phosphoramidate on Paramecium sp. with special emphasis on respiratory metabolism,growth, and generation time

The toxicological impacts of the increasing number of synthetic compounds present in the aquatic environment are assessed predominantly in laboratory studies where test organisms are exposed to a range of concentrations of single compounds. Protozoan cells are often used as bioindicators for the presence of xenobiotic compounds. In this article, we describe the inhibitory effect of a synthetic phosphoramidate derivative at different concentrations (40, 60, and 80?µmol?L^?1) on Paramecium sp., affecting its growth (proliferation) in concentration-dependent manner, as well as the generation time and response percentage. The LC₅₀ value determined for these protozoa was estimated at 60?µmol?L^?1 on 24?h of exposure. The respiratory metabolism of protozoan is perturbed at three concentrations, noting that the oxygen consumption was significantly increased at high concentrations after 18?h of exposure. In addition, the data can be used as reference values in further testing with other pesticides.