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101.
102.
不同磷质量浓度体系中pH变化对铜绿微囊藻和四尾栅藻竞争的影响 总被引:9,自引:3,他引:6
铜绿微囊藻和四尾栅藻分别是太湖中最为常见的蓝藻和绿藻.微囊藻在湖泊中形成优势是微囊藻水华发生的重要条件.在模拟太湖水的竞争实验(ρ(磷)分别为0.012,0.112,0.412和1.612 mg/L)中,四尾栅藻均形成优势,而且在稳定期时pH达到10以上.但用0.04 mol/L HCl将pH都降到5.8后,2种藻的增殖都出现明显的变化,在ρ(磷)低于0.412 mg/L时,四尾栅藻优势变得更加明显;而在ρ(磷)为1.612 mg/L时,铜绿微囊藻则形成优势.说明pH对蓝藻和绿藻竞争的影响在不同ρ(磷)的水体中是不同的. 相似文献
103.
Dr. M. Sam Mannan is one of the true pioneers in the process safety area, spending almost his entire lifetime in process safety and risk research. He was dedicated to ‘make safety second nature’ and published an impressive body of work. An overview of his research helps understanding the process safety area and provides insight in the legacy of this process safety pioneer. In this paper, 327 publications authored by Dr. Mannan from 1999 to 2019 in Web of Science core collection were downloaded and visually analyzed from four perspectives: his publication outputs, collaboration networks, topic areas, and highly cited papers and cited references. The results show a rapidly increasing trend in his research activity, mostly through journal publications. He published in 53 different outlets, with Journal of Loss Prevention in the Process Industries being most frequently selected. Dr. Mannan had a very active and diverse worldwide network, and collaborated with 18 different countries/regions, nearly 90 different institutions and 387 authors. His publications addressed process safety-related topics widely, including safety related to liquefied natural gas, explosions, runaway reactions, inherent safety, flammability and aerosol, and more recently resilience. Dr. Mannan's most cited paper focused on ‘fuzzy risk matrix’, whereas the most frequently cited reference in his work is ‘thermal hazard evaluation by an accelerating rate calorimeter’ by Townsend DI in 1980. Based on his most recent research activity, promising future directions for process safety research include resilience linked to risk assessment and management, for instance through the ‘safety triad’ concept he promoted shortly before passing away. 相似文献
104.
Comparative degradation between heavy and light crude oil mediated by nitrogen‐induced cell‐surface hydrophobicity 下载免费PDF全文
A bacterial strain UKMP‐10M2 isolated from a Malaysian petroleum refinery was able to degrade 84% of heavy Khafji sour crude and 68% of light Tapis sweet crude within seven days. Analysis of gas chromatography‐flame ionization detector chromatograms show the strain UKMP‐10M2 degraded up to 90% pristane and 50% phytane in heavy crude, but significantly lower pristane (50%) and phytane (30%) were degraded from the light crude. A mixture of aliphatic hexadecane and three‐ring phenanthrene better supported the growth of isolate UKMP‐10M2 compared to using phenanthrene alone, suggesting cometabolism influenced how crude oil with different individual hydrocarbon contents affected the degradation. Peptone as the source of nitrogen increases the emulsifying index in UKMP‐10M2 exposed to heavy Khafji sour crude 20% higher than in light Tapis sweet crude. However, BATH assay showed the same nitrogen source increases bacterial cell surface hydrophobicity of UKMP‐10M2 up to 14% higher in light Tapis crude oil compared to heavy Khafji. This study suggest the nitrogen source plays a decisive role in elevating UKMP‐10M2 bacterial cells hydrophobicity, and in correlation with types of crude oil. Phylogenetic tree analysis based on 16S rDNA sequence results identified the strain to be Rhodococcus ruber. 相似文献
105.
The scale, duration and intensity of conflicts over mineral resources vary greatly. However, they always involve, in varying proportions, the triad stakeholder model—corporation, state, community—each element of which is internally heterogeneous. Increasingly, new players are entering the scene: international non-governmental organizations (NGOs), environmental grassroots groups, indigenous transnational networks, international aid and development agencies. Nevertheless, conflicts and arrangements around access to and control over mineral resources can take the apparent form of dyadic relationships between companies and local communities, resulting in negotiated company-community agreements, often called “Impact and Benefit Agreements” (IBAs). In our analysis, local agreements on mineral resource governance are seen as building blocks in the production of mining policy “from below”, even though they seem at first sight to exclude the state. This paper argues that these agreements, and the negotiations surrounding them, inform debates around mining through both “horizontal diffusion” (influence on other localities facing similar situations) and “vertical diffusion” (influence on policy design and implementation at upper political and administrative levels). This diffusion may occur in a “positive” sense, effecting further change in line with the intent of the original agreement, or in a “negative” one, actually making substantive change less likely, whether at a community or policy level. We build this argument through two case studies from New Caledonia, in the south-west Pacific, where mining has long been a key issue, especially in the current context of “negotiated decolonization” launched by the 1998 Nouméa Accord. 相似文献
106.
The impacts of production disruption in Remanufacturing/Manufacturing (R/M) integrated supply chain on the sales and the methods of production disruption management were studied. A system dynamics model for the R/M integrated supply chain with production disruption was improved by system dynamics methodology. The numerical examples were shown to illustrate the simulation results. The impacts of different recovery times of production disruption on the sales were presented. In order to mitigate the disruption risks and ensure the sales at the needed sales ratio, the methods for setting multi-echelon inventory levels before the occurring of the production disruption and the methods for making back-up plans after the production disruption occurs were given. 相似文献
107.
As an effort to better utilize the microbial fuel cell (MFC) technology, we previously proposed an innovative MFC system named M2FC consisting of ferric-based MFC part and ferrous-based fuel cell (FC) part. In this reactor, ferric ion, the catholyte in the MFC part, was efficiently regenerated by the FC part with the generation of additional electricity. When both units were operated separately, the ferric-based MFC part produced approximately 1360 mW m−2 of power density with FeCl3 as catholyte and Fe-citrate as anolyte. The ferrous-based FC part with FeCl3 as catholyte and Fe-EDTA as anolyte displayed the highest power density (1500 mW m−2), while that with ferricyanide as catholyte and Fe-noligand as anolyte had the lowest power density (380 mW m−2). The types of catholytes and chelating complexes as anolyte were found to play important roles in the reduction of ferric ions and oxidation of ferrous ion. Linear sweep voltammetry results supported that the cathode electrolytes were electrically active and these agreed well with the M2FC reactor performance. These results clearly showed that ligands played critical role in the efficiency and rate for recycling iron ion and thus the M2FC performance. 相似文献
108.
用1971-2000年的30年逐日降水量资料,按旬统计汶川地震重灾县5-12月各旬的雨日、中雨日、大雨日、暴雨日的平均日数和气候概率,根据地震重灾区实际地质环境条件,降低强降雨强度条件,基于模糊综合评判法,按照最大隶属度原则对汶川特大地震重灾区的39个县进行地质灾害时空气候风险评估。结果表明:重灾区的地质灾害气候风险指数值存在两个高值期间,一个是5月中旬至7月上旬,另一个是8月下旬至9月下旬。而10月下旬至次年4月,重灾区降雨明显减少,绝大部分地区没有地质灾害气候风险;从地域分布来看,高风险区域主要集中在重灾区的西部和中部,风险等级为3~4级(风险较大或很大),东部地区风险等级为1~2级(中等风险或风险较小),但7月下旬高等级风险区位置集中在重灾区的南部和东部。 相似文献
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110.
采用微波消解一氢化物发生原子荧光光谱法同时测定芦苇中砷和镉,优化了试验条件。砷在0ug/L-80.0ug/L、镉在0ug/L~10.0ug/L范围内线性良好,检出限分别为0.010ug/L和0.012ug/L,样品测定的RSD为0.7%-2.0%,平均加标回收率为84.0%~107%。 相似文献