Vegetation changes in Conservation Reserve Program lands in interior Alaska

Over 14 million hectares of erosion prone cropland in the United States has been converted into grasslands through the Conservation Reserve Program (CRP) administered by the United States Department of Agriculture, however, studies of the effects of CRP enrollment on plant communities and subsequent plant succession are largely lacking. In Delta Junction, Alaska plant communities in CRP fields are transitioning from grasslands to shrub dominated plant communities, which are resulting in compliance problems with program regulations that state “fields must be maintained in a condition that permits easy conversion to cropland”. To determine plant succession and how previous land management and soils might influence the transition, we measured plant populations in 20 CRP fields throughout Delta Junction using modified-Whittaker plots. These data were combined with data on current management practices, previous farming history, soils, soil properties, diversity indices, and time since land was cleared and analyzed with nonmetric multidimensional scaling ordination to determine factors that influence plant succession. Time in the CRP was the only factor consistently influencing plant succession. As time in the CRP increased, the planted introduced grasses brome grass (Bromus inermis) and red fescue (Festuca rubra) and the native pteridophyte (Equisetum arvense) decreased, whereas a native grass (Calamigrostis canadensis), five native forb, two native shrub, and three native tree species increased. Plant diversity increased at a rate of more than 2 species per 1000 m² per year. Regression analyses of plant species and plant groups using time in the CRP as the dependent variable resulted in the identification of outlier CRP fields with significantly more or less than expected covers of vegetation. All fields with these outliers had reasonable explanations for the differences in cover that were unrelated to the overall rate of plant succession. Current management practices will result in incompliant fields and different management practices that result in woody vegetation control is key to maintaining CRP fields in compliance.     

Muhlbauer评分法在输油管道风险评价中的应用及分析

与其它运输方式相比,管道运输在正常运行情况下,其环境污染小。但是,产生事故后其环境风险大。本文利用Muhlbauer评分法对天津-北京航空煤油输送管道进行了风险评价,经过模拟计算后,定量分析了该输油管道的相对风险数,并提出了提高管道运行安全性的措施。评价结果表明:该管道的相对风险数为59,存在一定风险,但风险可接受。相对风险数中可变因素占66.5%,在不增加项目基建投资基础上,通过加强管理等措施,可提高可变因素的指数分值和相对风险数,使管道安全性能提高16.1%。     

Effects of sediment dredging on water quality and zooplankton community structure in a shallow of eutrophic lake

Effects of suction dredging on water quality and zooplankton community structure in a shallow of eutrophic lake,were evaluated.The results showed that a decreasing trend for levels of phosphorus,organic matter,total suspended solids,Chlorophyll a and Secchi transparency in the water column was found,while levels of water depth,electrical conductivity,total dissolved solids and NO 3--N concentration increased markedly post-dredging.The effects of dredging on dissolved oxygen,pH value and temperature were alm...     

Production of a newly isolated Paenibacillus polymyxa biocontrol agent using monosodium glutamate wastewater and potato wastewater

A phyllosphere bacterial strain EBL-06 was isolated from wheat leaves. The morphology, cultural characteristics, phospholipid fatty acids, physiological and antagonistic fungus activities of this strain were investigated. A phylogenetic tree was constructed by comparing with the published 16S rDNA sequences of the relevant bacteria. The results showed that the isolate EBL-06 was a strain of Paenibacillus polymyxa; this strain performed a high level of antagonistic fungus activity toward a broad spectrum of phytopathogens, such as Botrytis cinerea, Cladosporium cucumerinum, Fusarium spp. The isolate EBL-06 can grow well using monosodium glutamate wastewater (MGW) and potato wastewater (PW) as culture medium. The maximum yield of 6.5 × 10 9 CFU/mL of the isolate EBL-06 anti-fungus biocontrol agent was reached in 15 hr cultivation at 28°C, pH 6.0–7.5 using the mixture of MGW and PW (1:9).     

基于神经网络评估的密封点泄漏检测

介绍了运用神经网络评估方法对石化生产装置泄漏风险进行量化评估的主要程序：输入变量的选择、风险指标的确定及总风险评估指标的确定等。以某炼油厂柴油加氢精制装置的应用为例,说明该方法可以指导企业根据最终确定的风险等级制定泄漏检测计划,对高风险部位增加检测的频次,既能有效监控密封点的密封效果,又减少不必要的资源投入。     

泥水平衡顶管技术在川气东送管道工程中的应用

介绍了泥水平衡顶管施工中采取的改进措施,实践证明,改进后未发生任何安全事故,且比预期提前了18天。     

土壤中重金属测定方法探讨

采用硝酸+氢氟酸+高氯酸全分解方法消解土壤样品,并结合原子吸收分光光度法和标准加入法测定土壤中、锌、铅、镉、镍、总铬的含量.结果表明,该方法具有操作简便、快速,节省试剂,准确可靠等特点:实际土壤样品的检测结果完全能满足环境土壤样品测定的要求.     

效益型资源化啤酒废水处理技术应用及效果

本项处理技术屏弃了以往环境处理技术沿用的生产末端处理路线.根据啤酒生产工艺特点,在全面分析,平衡工艺废水的特性,数量及排放规律的基础上提出综合治理方案,着重于从废水中提取有用物质和能源,治理过程中把废水当做资源加以利用,而且具有明显低投入高增益的经济效益.装置2年来运行结果证明:核心技术——UASB 高效,实用,易操作,运行稳定居国内领先水平,其主要技术指标达到国内外同类研究的先进水平.该项技术可在啤酒行业及以粮食为原料的其它酿造行业和食品加工业中推广应用,并已被国家科委列为《国家级科技成果重点推广计划》及国家环保局最佳实用技术.     

包头市大气氟化物排放总量控制管理研究

结合实践,阐述了总量控制管理的必要性和可能性;介绍和分析了总量管理的内容和程序;对主要问题提出对策和措施;形成运行管理机制,提出排氟量计算、污染物输送扩散模型等构成的技术支持系统。