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741.
742.
Restoring riparian ecosystems in human-dominated landscapes requires attention to complexity, and consideration of diverse drivers, social actors, and contexts. Addressing a Global North bias, this case study uses a mixed-method approach, integrating historical data, remote sensing techniques and stakeholder perceptions to guide restoration of a river in the Western Cape, South Africa. An analysis of aerial photographs of the riparian zone from 1953 to 2016 revealed that although anthropogenic land conversion happened primarily before the 1950s, several land use and land cover classes showed marked increases in area, including: waterbodies (+ 1074%), urban areas (+ 316%), alien weeds (+ 311%) and terrestrial alien trees (+ 79%). These changes have likely been driven by land fragmentation, disturbance, and agricultural intensification. Stakeholder interviews revealed that despite the clear need for restoration, several barriers exist to successful implementation; these stem from inadequate financial resources, inappropriate funding models, institutional challenges, and a lack of techno-scientific knowledge. We give several recommendations to overcome these barriers.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01691-y. 相似文献
743.
744.
考察了处理效果良好的循序间歇式废水生物除磷试验装置内活性污泥的微生物组成及其优势菌的磷代谢特性。试验结果表明,活性污泥混合液中的优势菌为假单胞菌属,其次是气单胞菌属和棒杆菌属,仅发现少量的不动杆菌属。当以乙酸钠为基质时,假单胞菌属于好氧培养过程中能明显除磷,其效果与厌氧/好氧培养过程的相近。另外,在好氧条件下,以乙酸钠为基质培养时,向培养基内滴加H2SO4可导致假单胞菌产生磷释放现象,滴加NaOH或NaHCO3时,则发生过量摄磷现象,并且加NaOH所引起的磷摄取量较NaHCO3的大。 相似文献
745.
746.
基于破煤理论建立了采煤机的力学模型,采用ADAMS建立采煤机刚柔耦合模型,并解决了边界条件添加、接触法向力提取等技术问题,分析了行星轴、架的可靠性;基于行星减速机构强度校核基本原理,开发了行星齿轮强度校核软件,以虚拟仿真中的动态接触法向力为输入,对某公司两种行星减速机构设计方案中各齿轮的接触应力和弯曲应力进行研究。该方法解决了传统分析中齿轮受力无法确定以及采用有限元软件无法求解齿根弯曲应力、求解接触应力时间过长的不足。结果表明:二级行星减速机构采用4行星轮结构要优于采用3行星轮方案,传动更稳定、可靠。 相似文献
747.
Xingyu Liu Bowei Chen Jinghe Chen Laichang Zou Jiankang Wen 《Chemistry and Ecology》2016,32(5):419-431
The Zijin heap bioleaching plant started operation by the end of 2005; due to the proximity of the Ting River, concerns rose about the migration of acidophiles outside of the heap. In this study, 53 soil samples and 51 liquid samples were collected, and the biogeographical distribution of acidophiles was investigated using clone libraries and real-time polymerase chain reaction (PCR), the physicochemical characteristics were analysed by Inductively Coupled Plasma Optical Emission Spectrometry (ICP). The results indicated the bioleaching system had some influence on the surrounding environment. Both microbial community and physiochemical index emerged correlation with distance of sampling sites from bioleaching system, mainly limited in the zone 30?m outside bioleaching system. Correlation analysis indicated the migration of different acidophiles was influenced by different factors. Leptospirillum had higher migration capability than the other acidophiles, and such migration capability was one of the important influence factors for its distribution. Environment factors and survival ability were the key influence factors for Acidithiobacillus, Sulfobacillus and Ferroplasma to survive in the surrounding environment. 相似文献
748.
强震作用下地埋结构的数值模型 总被引:2,自引:0,他引:2
应用时域边界元法研究了结构 介质动力相互作用问题。假设摩擦遵守库仑定理 ,当入射波足够强时界面会出现局部滑移、分离。由于边界上的区域 (滑移、分离和粘着 )是未知的 ,所以 ,笔者研究的实际上是个复杂的边界非线性问题。该模型对评估和预测地埋结构在动荷载下的安全具有重要的理论价值 相似文献
749.
印染废水处理工程应用研究 总被引:3,自引:0,他引:3
印染厂生产废水具有高浓度、高色度和含有大量难降解有机物的特点 ,用单一的化学法或生物法处理效果不好。江阴某印染厂采用物化 +三级生化 +物化法处理印染生产废水 ,设计处理能力 36 0m3 d ,废水进水CODCr,BOD5,SS和色度分别为 2 0 0 0~ 30 0 0mg L ,6 0 0~ 70 0mg L ,350~ 50 0mg L和 50 0~ 1 0 0 0倍 ,经处理后 ,出水稳定并达到污水排放一级标准。 相似文献
750.
The removal of disinfection by-products formation potential(DBPFP) in artificially intensified biological activated carbon(IBAC) process which is developed on the basis of traditional ozone granular activated carbon was evaluated. By IBAC removals of 31% and 68% for THMFP and HAAFP were obtained respectively. Under identical conditions, the removals of the same substances were 4% and 32% respectively only by the granular activated carbon(GAC) process. Compared with GAC, the high removal rates of the two formed potential substances were due to the increasing of bioactivity of the media and the synergistic capabilities of biological degradation cooperating with activated carbon adsorption of organic compounds. A clear linear correlation ( R^2 = 0.9562 and R^2 = 0.9007) between DOC HAAFP removal rate and Empty Bed Contact Time(EBCT) of IBAC process was observed, while that between THMFP removal rate and EBCT of GAC was R^2 = 0.9782. In addition certain linear correlations between THMFP, HAAFP and UV254 ( R^2 = 0.855 and R^2 = 0.7702) were found for the treated water. For IBAC process there are also more advantages such as long backwashing cycle time, low backwashing intensity and prolonging activated carbon lifetime and so on. 相似文献