无锡市桃花山生活垃圾填埋场扩建工程渗沥液导排设计

通过分析无锡市桃花山垃圾填埋场原工程渗沥液导排在实际运行中存在的问题,针对当前卫生填埋场的现状,提出扩建工程在原工程和扩建工程和新场渗沥液导排2个关键环节上采取的措施。     

The effect of protected areas on forest disturbance in the Carpathian Mountains 1985–2010

Protected areas are a cornerstone for forest protection, but they are not always effective during times of socioeconomic and institutional crises. The Carpathian Mountains in Eastern Europe are an ecologically outstanding region, with widespread seminatural and old‐growth forest. Since 1990, Carpathian countries (Czech Republic, Hungary, Poland, Romania, Slovakia, and Ukraine) have experienced economic hardship and institutional changes, including the breakdown of socialism, European Union accession, and a rapid expansion of protected areas. The question is how protected‐area effectiveness has varied during these times across the Carpathians given these changes. We analyzed a satellite‐based data set of forest disturbance (i.e., forest loss due to harvesting or natural disturbances) from 1985 to 2010 and used matching statistics and a fixed‐effects estimator to quantify the effect of protection on forest disturbance. Protected areas in the Czech Republic, Slovakia, and the Ukraine had significantly less deforestation inside protected areas than outside in some periods; the likelihood of disturbance was reduced by 1–5%. The effectiveness of protection increased over time in these countries, whereas the opposite was true in Romania. Older protected areas were most effective in Romania and Hungary, but newer protected areas were more effective in Czech Republic, and Poland. Strict protection (International Union for Conservation of Nature [IUCN] protection category Ia‐II) was not more effective than landscape‐level protection (IUCN III‐VI). We suggest that the strength of institutions, the differences in forest privatization, forest management, prior distribution of protected areas, and when countries joined the European Union may provide explanations for the strikingly heterogeneous effectiveness patterns among countries. Our results highlight how different the effects of protected areas can be at broad scales, indicating that the effectiveness of protected areas is transitory over time and space and suggesting that generalizations about the effectiveness of protected areas can be misleading.     

铁氮掺杂碳纳米管/纤维复合物制备及其催化氧还原的效果

阴极催化剂是影响微生物燃料电池(microbial fuel cell,MFC)性能的关键因素.通过研究制备成本低廉、氧还原反应(ORR)催化活性高的阴极催化剂来替代Pt/C对于实现MFC规模化应用具有重大意义.研究采用化学气相沉淀法,以三聚氰胺作为碳氮前驱物、以黑珍珠2000或乙炔炭黑作为碳源,外加醋酸亚铁作为铁前驱物,合成了两种铁氮掺杂碳纳米管/纤维复合物(FeNCB和FeNCC),作为MFC的阴极催化剂.通过循环伏安法和旋转圆盘-环电极分析FeNCB、FeNCC和Pt/C的ORR催化活性的差异,并用MFC验证其差异.结果表明,FeNCB性能与Pt/C相当,优于FeNCC,其催化路径是通过4电子途径催化氧还原反应;MFC-FeNCB性能略优于MFC-Pt/C,显著优于MFC-FeNCB有助于MFC的扩大化,其最大功率密度为1 212.8mW·m~(-2),开路电压为0.875 V,电池稳定电压为(0.500±0.025)V.用X射线衍射、X射线光电子光谱、拉曼光谱等进一步分析显示,复合物中碳纳米管管径的大小、铁氮掺杂的类型和含量以及氧含量是引起制备的复合物催化氧还原性能差异的原因所在.     

突扩巷道模型风流态的LDA与PIV联合测试

针对传统的接触式瞬时速度测量方法的局限性,采用非接触测量技术激光多普勒测速仪(LDA)及粒子成像测速仪(PIV)对平直巷道及断面突扩后风流状态进行试验测试。在巷道试验模型条件下,PIV技术可以瞬时获得巷道突扩流场信息,平直巷道速度流线基本呈平滑直线,突扩隅角有大涡存在,并且涡流区测风方向极不稳定,而且风速很低,风速平均值在0.1~0.2 m/s波动,表明在煤矿井下测风时可以有条件地忽略涡流区。LDA技术测试得到巷道断面各点统计平均流速,由于受突扩涡流及二次流的影响,平直巷道断面风速从壁面以跃迁方式"突变"达到均值,断面风速分布呈近似均等的动态波浪线分布而非准抛物线型分布。结果表明,LDA与PIV测量技术联合应用可以测试以湍流为特征的巷道流场风流变化情况。     

Experimental evidence for the effects of task repetitiveness on mental strain and objective work performance

People frequently have to work in high repetitive jobs. Previous research has focused exclusively on the effects of task repetitiveness on well‐being, while neglecting effects on work performance. In the present study, we aimed to fill this void by conducting two workplace simulations with experimental manipulations of task repetitiveness. Participants worked for about 5 hours at either a computer workstation, compiling computer hardware packages according to customer requests (Experiment 1, N = 160), or at an assembly line, piecing together equipment sets for furniture (Experiment 2, N = 213). Both experiments provide consistent evidence that high repetitiveness has a detrimental effect on well‐being, whereas work performance increases under conditions of high repetitiveness. On a practical level, our study hence shows that high task repetitiveness is a double‐edged sword for both employees and organizations. On a conceptual level, our findings emphasize the necessity to account for both mental strain and work performance when examining the effects of task repetitiveness. Copyright © 2014 John Wiley & Sons, Ltd.     

BEDROCK CONTROLS ON STREAM CHANNEL ENLARGEMENT WITH URBANIZATION,NORTH CENTRAL TEXAS1

Loss due to channel erosion in the Dallas, Texas, area is estimated to approach one-half million dollars in the last several years. Hydrogeomorphic analysis of natural and urban chalk and shale watersheds was performed in the central Texas area on watersheds ranging in size from 0.5 to 10 square miles in an effort to more adequately predict channel enlargement due to urbanization. Chalk watersheds were found to have greater drainage density, greater channel slope, lower sinuosity, and greater discharge per unit area than similar sized shale watersheds under natural conditions. With subsequent urbanization of the watersheds, chalk channel enlargement was from 12 to 67 percent greater than shale channel enlargement for similar sized watersheds. Greater enlargement in chalk channels is attributed to greater channel velocities and unit tractive force. Vegetation seems to play a significant role in influencing channel adjustments to the new flow regimes brought on by urbanization. Channel response to urbanization is documented and specific nonstructural guidelines are proposed which could reduce structural loss along urban stream channels.     

石首天鹅洲六合垸扩大麋鹿栖息地初析

自石首麋鹿国家级自然保护区设立以来,麋鹿种群得到了有效发展。因各种因素综合作用,现有保护区已呈现容纳量不足的趋势。相较其它湿地,依据岛屿生物地理学“平衡理论,”与麋鹿保护区相连通的六合垸似乎在扩大麋鹿栖息地方面具有地理优势。文章侧重从景观学(形状、连接度、廊道构建)及社会(移民)两个角度对其优势度状况作尝试性分析,进而得出六合垸并不具有明显优势的初步结论。     

脉冲电晕等离子法烟气脱硫的扩大实验研究

采用实际锅炉烟气进行脉冲电晕等离子法脱硫的扩大实验，得到了与模拟烟气进行的小实验相近的结果。结果表明，脉冲电晕等离子法能有效去除锅炉烟气中的ＳＯ２，脱硫率可达９５％以上。烟气的停留时间、脉冲电源放电功率及添加ＮＨ３等对脱硫率有较大影响，前两者越大，脱硫率越高，但应与处理量、能耗综合考虑，有函数关系η＝１１８．０（Ｐ／Ｑ）０．１１１１。加ＮＨ３量选取与烟气含ＳＯ２量１：１的当量比最有利，产物可用做肥料。试验结果为实用性放大提供了基础资料。     

A Sediment Budget for an Urbanizing Watershed, 1951‐1996, Montgomery County, Maryland,U.S.A.1

Abstract: Despite widespread interest, few sediment budgets are available to document patterns of erosion and sedimentation in developing watersheds. We assess the sediment budget for the Good Hope Tributary, a small watershed (4.05 km²) in Montgomery County, Maryland, from 1951‐1996. Lacking monitoring data spanning the period of interest, we rely on a variety of indirect and stratigraphic methods. Using regression equations relating sediment yield to construction, we estimated an upland sediment production of 5,700 m³ between 1951 and 1996. Regression equations indicate that channel cross‐sectional area is correlated with the extent of development; these relationships, when combined with historical land use data, suggest that upland sediment yield was augmented by 6,400 m³ produced by enlargement of first‐order and second‐order stream channels. We used dendrochronology to estimate that 4,000 m³ of sediment was stored on the floodplain from 1951‐1996. The sediment yield from the watershed, obtained by summing upstream contributions, totals 8,100 m³ of sediment, or 135 tons/km²/year. These results indicate that upland erosion, channel enlargement, and floodplain storage are all significant components of the sediment budget of our study area, and all three are approximately equal in magnitude. Erosion of “legacy” floodplain sediments originally deposited during poor agricultural practices of the 19th and early 20th Centuries has likely contributed between 0 and 20% of the total sediment yield, indicating that these remobilized deposits are not a dominant component of the sediment yield of our study area.     

Compliance with EU environmental law. The iceberg is melting

ABSTRACT

The European Union (EU) has become the main driver for environmental policy output for its member states whose number has more than tripled over the past four decades. The EU’s deepening and widening has led researchers to expect more non-compliance with EU environmental legislation. In fact, however, the implementation gap has narrowed over the past 25 years. Except for Southern enlargement, taking on new member states has not exacerbated the EU’s compliance problem in the field of environmental policy. Nor has the expansion of the environmental acquis. This is explained by the European Commission’s strategies of managing and enforcing compliance. EU environmental policy has become less demanding on member states since it increasingly tends to amend existing rather than set new legislation. Simultaneously, the Commission has developed new instruments to strengthen member state capacities to implement EU environmental legislation.