Effect of Ce(3+) on soluble microbial products production in anaerobic granular sludge digestion

Upflow anaerobic sludge bed reactors fed on glucose were used to investigate the effects of Ce(3+) on soluble microbial products (SMP) production, which is the majority of the residual chemical oxygen demand present in the effluent. It was found that Ce(3+) concentration of 0.05 mg/L had no significant effect on the amount of SMP production, whereas that of 1 mg/L led to the increase in SMP production. The molecular-weight distribution and carbohydrate analysis indicated that an increase in SMP production may be partly attributed to the release of extracellular polymeric substances (EPS) into the bulk solution resulted from cerium toxicity, and the nucleic acids analysis suggested that increased cell lysis also contributed to SMP accumulation in the presence of Ce(3+). The increase in SMP production in the presence of Ce(3+) is possibly a consequence of the release of EPS and increased cell lysis due to cerium toxicity.     

Effective degradation of para-chloronitrobenzene through a sequential treatment using zero-valent iron reduction and Fenton oxidation

In this study, zero-valent iron (ZVI) was used to pretreat para-chloronitrobenzene (p-CNB), and the major product was para-chloroaniline (p-CAN). By adding H(2)O(2) directly, further p-CAN degradation can be attributed to Fenton oxidation because ferrous ions (Fe(2+)) released during the ZVI corrosion could be used as an activator for H(2)O(2) decomposition. In the reduction process, the reduction efficiency of p-CNB as well as Fe(2+) concentration increased with increasing iron dosage and decreasing solution pH. Under the optimal conditions, 25 mg L(-1) of p-CNB could be transformed in 3 h when initial solution pH was 3.0 and ZVI dosage was 2.0 g L(-1). A sufficient amount of Fe(2+) (50.4 mg L(-1)) was obtained after the above reaction to activate H(2)O(2). In the Fenton process, the oxidization of p-CAN was also more effective in acidic conditions and it increased with increasing H(2)O(2) concentration. The control experiments showed that the sequential treatment was more effective than Fenton oxidation alone in treating p-CNB wastewater since the removal rate of total organic carbon (TOC) was improved by about 34%. It suggested that the amino function group is more susceptible to oxidative radical attack than the nitro function group. Therefore, sequential treatment using zero-valent iron reduction followed by Fenton oxidation is a promising method for p-CNB degradation.     

水利工程竣工验收检测评价体系构建

通过调查分析全国有代表性的水利工程质量检测和竣工验收检测的技术资料,以及对工程建 设行业已有检测技术标准的对比分析和研究,提出了水利工程竣工验收检测分部和检测单元的划分、 检测项目和抽样数量、检测技术和评价方法,以及检测评价体系的构成,为制定水利工程质量验收检 测评价技术标准提供技术支持。     

非球形风沙粒子的低雷诺数绕流阻力特性研究

采用有限体积法计算了均匀来流条件下圆柱体和正四面体颗粒的低雷诺数三维绕流流场,得到了颗粒在不刚来流方向下的速度分布、压力分布,分析了其阻力特性.结果表明,非球型颗粒的在风场中的绕流阻力大小受来流方向的影响明显,在特定方向阻力最大,这与绕流后的剪切层结构有关.通过比较发现,以往非球型颗粒阻力经验公式给出的只是单一来流方向时的阻力值,而非平均值.根据计算结果给出了新的拟合非球体阻力系数计算公式,可以更准确地估算非球型风沙颗粒各来流方向的平均阻力值.     

基于GIS的乌江流域新安江模型参数率定

为了使新安江模型的运用更能真实反映流域的基本特征及产汇流机理,利用地理信息系统空间分析的功能,由数字高程模型导出乌江武隆以上流域的流域排水网,并在此基础上提取汇流长度及坡度等地形特征值。在地理信息系统平台上,计算出流域下垫面的植被、土壤、地貌等特征值,并将其与流域模型参数建立相关关系。结果表明,各流域模拟的确定性系数及模拟精度均较高。因此,预报结果更加合理,理论依据也更加可靠。     

CFG桩复合地基静载检测方法探讨

某大型低层建筑群采用CFG桩进行地基处理.本文应用JGJ106-2003<建筑基桩检测技术规范>中的静载检测方法,对经CFG桩处理的粉质黏土地基承载力进行检测.通过对检测过程和成果的分析总结,对规程规定方法中有关预载、级差超限、加荷控制、卸载观测等方面不明确之处进行了探讨.     

巴山水电站面板堆石坝变形监测控制网的建立

介绍重庆巴山混凝土面板堆石坝外部变形监测控制网的建立与施测,并对监测控制网计算进行了分析,总结了该控制网建立过程中的经验,为类似条件下水电工程平面变形监测控制网和水准网的建立提供参考。     

一种高性能入侵防御系统的设计与实现

随着高速网络的普及,传统的入侵防御系统在数据包的高速捕获和实时处理方面,已经不能满足性能上的要求。设计并实现了一种高性能入侵防御系统,PF_RING DNA Intrusion Prevention System:PDIPS。PDIPS运行在通用多核平台,采用PF_RING的DNA技术,实现对数据包的线速捕获,同时采用多线程和CPU绑定技术并行地处理数据包,提高了系统的整体性能。试验结果表明,在相同的测试环境下,本系统与传统的入侵防御方案相比,在性能上有较好的提升,可以适应千兆环境的需求。     

下井人员生命体征传感器的设计

针对目前中国矿井人员健康在线监测技术落后、未实现下井人员身体状况在线监测的现状,介绍了一种矿井人员区域定位与健康监测系统的总体结构,重点研究了下井人员健康监测传感器技术,提出了体温监测传感器、脉搏监测传感器、救护队员姿态监测传感器及一种集成的生命体征监测传感器的设计方案,对预防矿井潜在医疗紧急事件具有重要意义。     

薄煤层视频监控系统设计

根据薄煤层工作面的特点设计了视频监控系统,介绍了系统的总体设计及软硬件设计。该系统实现了对薄煤层工作面的实时监控,系统性能稳定,图像清晰,画面流畅,通信延时短,将大大提高采煤效率,降低工人的劳动强度。