Advanced thermal characterization of fractionated natural organic matter

This work focuses on an experimental investigation of the thermodynamic properties of natural organic matter (NOM), and whether fractions of NOM possess the same thermodynamic characteristics as the whole NOM from which they are derived. Advanced thermal characterization techniques were employed to quantify thermal expansion coefficients (alpha), constant-pressure specific heat capacities (C(p)), and thermal transition temperatures (T(t)) of several aquatic- and terrestrial-derived NOM. For the first time, glass transition behavior is reported for a series of NOM fractions derived from the same whole aquatic or terrestrial source, including humic acid-, fulvic acid-, and carbohydrate-based NOM, and a terrestrial humin. Thermal mechanical analysis (TMA), standard differential scanning calorimetry (DSC), and temperature-modulated differential scanning calorimetry (TMDSC) measurements revealed T(t) ranging from -87 degrees C for a terrestrial carbohydrate fraction to 62 degrees C for the humin fraction. The NOM generally followed a trend of increasing T(t) from carbohydrate to fulvic acid to humic acid to humin, and greater T(t) associated with terrestrial fractions relative to aquatic fractions, similar to that expected for macromolecules possessing greater rigidity and larger molecular weight. Many of the NOM samples also possessed evidence of multiple transitions, similar to beta and alpha transitions of synthetic macromolecules. The presence of multiple transitions in fractionated NOM, however, is not necessarily reflected in whole NOM, suggesting other potential influences in the thermal behavior of the whole NOM relative to fractionated NOM. Temperature-scanning X-ray diffraction studies of each NOM fraction confirmed the amorphous character of each sample through T(t).     

Characterization of Aerobic Bacteria Involved in Degrading Polyethylene Glycol (PEG)-3400 Obtained by Plating and Enrichment Culture Techniques

Polyethylene glycol (PEG) 3400-degrading aerobic bacteria were isolated from tap water and wetland sediments and then characterized. Only one Sphingomonas strain was obtained in enrichment cultures from each inoculum source whereas a total of 15 bacterial strains were isolated on agar plates. Nine of the 15 isolates were confirmed as PEG 3400 degraders. Three of the 9 PEG 3400 degraders were Gram-negative bacteria belonging to the genus Pseudomonas and genus Sphingomonas. The remaining six isolates were Gram-positive bacteria belonging to genera Rhodococcus, Williamsia, Mycobacterium and Bacillus. PEG 3400 was quantified at 194 nm spectrophotometrically and, at the same time, the growth of two Gram-negative (isolates P1 and P7) and five Gram-positive (isolates P2, P3, P4, P5 and P6) PEG 3400-degrading bacteria were assayed in liquid media and on agar plates amended with PEG 3400, and also on Nutrient Agar plates and pure agar plates without PEG 3400 addition. No growth was observed on the pure agar plates for all the tested strains for a period of 31 days. All tested PEG 3400 degraders showed much lower viability in liquid culture than on the corresponding agar plates in the presence of PEG 3400. Two Gram-negative isolates P1 and P7 did not show significant growth advantage over the Gram-positive isolates both on the agar plates and in the liquid medium amended with PEG 3400. Our results suggest that diversity of PEG degrading bacteria is high in the environments and culturing techniques affect the successful isolation of the bacteria responsible for degradation.     

开发洋口港的自然优势和宏观功能

本文根据近几年对洋口港的调查实测资料，分析了建深水港的可行性，并提出为解决长江口通海航道水深不足，充分发挥南通港港群机能等问题，供有关部门参考。     

分子筛在铅污染土壤修复中的应用研究

采用溶液试验,从待选钝化材料中初步筛选出对Pb具有较好钝化效果的钝化材料,运用经典混料设计的试验方法,将优选出的13X分子筛、凹凸棒土、粉煤灰三种钝化材料复配成钝化剂,添加到Pb含量为1 500mg/kg的污染土中,添加量为污染土的20％,并保持土壤的含水率35％,3天后取钝化后土壤,采用(HJ/T 300-2007)(固体废物浸出毒性浸出方法醋酸缓冲溶液法)测其浸出液中的重金属Pb含量,采用Minitab软件对混料设计试验数据进行处理,优选出钝化重金属Pb的最佳钝化剂配方:分子筛25％,凹凸棒土42.6％,粉煤灰32.4％,钝化后浸出液中重金属Pb含量为0.027 1 mg/L,明显低于地表水质量标准的Ⅲ类标准0.05 mg/L.     

基于两高司法解释的突发环境事件应急监测风险管理的思考

突发环境污染事故的发生,往往伴随着环境违法行为,因此突发性环境污染监测涉刑的可能性更大.因此环境监测站在实施突发性环境污染事件监测工作时,在环境监测环节及时收集可能的违法证据,形成证据链,为复现环境污染事件提供证据,为司法界入及时提供技术支持.根据风险管理原则,采用矩阵法对涉刑下的突发性环境事件应急监测进行了风险事件识别和风险评价,详细地对涉刑情形下的突发性环境事件应急监测进行环境分析,并提出了相应的风险应对措施,为环境监测系统防范和规避风险提供参考.     

A cross‐level model of shared leadership,meaning, and individual creativity

Research on leadership and creativity is dominated by the study of leadership from people in formal leadership positions. The very nature of creativity requires self‐direction, however. This points to shared leadership, a process in which members dynamically share the leadership role, as a particularly relevant influence to consider. Drawing on psychological empowerment theory, we develop the shared leadership perspective on individual creativity. We argue that shared leadership has a cross‐level influence on individual creativity that is mediated by the experience of meaning of work and moderated by individual differences in power distance value: for individuals lower on power distance, shared leadership has a positive linear relationship with individual creativity; for individuals higher on power distance, shared leadership has a curvilinear relationship with individual creativity that is decreasingly positive. Using a sample of 623 members from 95 teams in 34 Chinese organizations, we find support for this multilevel model. Findings offer theoretical implications for shared leadership and creativity research and provide managerial implications.     

生态修复技术在富营养化水库水质改善中的应用研究

2006年初对广东省大镜山水库实施了生态修复工程,工程运行一年后,对该生态修复工程的效果进行了分析,结果表明：生态修复技术实施一年后,大镜山水库富营养化水平明显降低。与进水口（C区）相比,生态修复工程区（A、B区）透明度增加,氮、磷营养盐含量都有不同程度的降低。生态修复工程区TN、NH4-N与C区同期比最大降幅分别达19.6%、90.4%,TP、PO4-P同期比最大降幅分别达49.5%、67.5%,同时生态修复工程区内的叶绿素浓度也明显低于C区。     

Comparison between inhibitor and uncoupler for minimizing excess sludge production of an activated sludge process

In order to study the minimization of excess sludge production, the reduction in the excess sludge production in the presence of an inhibitor and uncoupler was studied in this work. The experimental results show that such an addition could effectively reduce the production of excess sludge. With the energy uncoupling model established in this work, energy uncoupling coefficient (E _u) was used to evaluate the reduction in excess sludge production. The energy uncoupling coefficients in the presence of dinitrophenol (dNP), Zn²⁺, and Cu²⁺ was 0.75, 0.46, and 0.18, respectively. The analysis demonstrated that energy spilling occurred in the presence of dNP, and that dNP was an effective uncoupler for reducing the production of excess activated sludge without affecting the microbial respiration activity.     

模拟纳污水体底质参数变化

本文介绍了模拟纳污水体中ＷＡＲ，ＷＭＲ，ＷＣＨ，ＳＡＲ，ＳＭＲ，ＳＳＦ和ＲＯＣ的变化。过程曲线表明水体污染时底质参数出现累积现象。     

Detection of geosmin and 2-methylisoborneol by liquid-liquid extraction-gas chromatograph mass spectrum (LLE-GCMS) and solid phase extraction-gas chromatograph mass spectrum (SPE-GCMS)

Two sample preparation methods were introduced and compared in this paper to establish a simple, quick and exact analysis of geosmin and 2-methylisoborneol. LC-18 column was employed in solid phase extraction (SPE), 1.0 mL of hexane was adopted in liquid-liquid extraction (LLE), and the extracts were analyzed by gas chromatograph mass spectrum (GCMS) in selected ion mode. Mean recoveries of SPE were low for 2-methylisoborneol (2-MIB) and geosmin (GSM) with values below 50%. For LLE, the recoveries were satisfyingly above 50% for 2-MIB and 80% for GSM. Detection limits of the LLE method were as low as 1.0 ng/L for GSM and 5.0 ng/L for 2-MIB. A year-long investigation on odor chemicals of drinking water in Shanghai demonstrated that in the summer, there was a serious odor problem induced by a high concentration of 2-MIB. The highest concentration of 152.82 ng/L appeared in July in raw water, while GSM flocculation was minimal with concentrations below odor threshold.