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排序方式: 共有235条查询结果,搜索用时 46 毫秒
41.
42.
Optimization of the recovery of plastics for recycling by density media separation cyclones 总被引:1,自引:0,他引:1
Gent Malcolm Richard Menendez MarioToraño Javier Torno Susana 《Resources, Conservation and Recycling》2011,55(4):472-482
Material recovery processes are presented as the optimum option for recycling plastic wastes as a means of recovering hydrocarbon resources. There exist a large variety of automated material recovery processes for recycling of such wastes but each with significant limitations. Of these, the separation based on differences in densities is advocated as the optimum process either for producing recycled products or preparing wastes for subsequent recovery processing.Density separation processes based on cyclone type density media separation (DMS) is presented as an important, potential method for increasing plastics recycling process capacities. It is demonstrated to have the capacity to separate a significantly larger range of particle sizes than those presently processed industrially. The mathematical relationship for the prediction of quality of typical LARCODEMS type density media separations by particle size and density as expressed by the Ecart Probable is presented.A proposed device configuration is presented for density media separation to optimize the recovery and purity of both density fractions produced. It is also suggested that to be economically viable, a large scale of operation is required for industrial plastics recycling operations recovering and producing a number of different plastics with a purity to be used as a substitute for virgin material. 相似文献
43.
Rosamund McDougall 《The Environmentalist》2008,28(2):155-157
Europe’s growing energy deficit and destabilising climate may lead the EU and its constituent member states to change its
attitude to population size and growth. 相似文献
44.
Impacts on industry of Europe's emerging chemicals policy REACh 总被引:1,自引:0,他引:1
For Europe, a new regime in chemicals regulation is about to start. After the proposal of the European Commission concerning the Registration, Evaluation and Authorization of Chemicals (REACh) passed its readings in the European Parliament and some differences with the European Council of Ministers were resolved, the regulation will come into force in June 2007. This paper is focused on the question how serious the cost burdens for industry induced by REACh will be, and whether the New European Member States (NMS) which joined the European Union in May 2004 will be able to cope with the regulation. This evaluation has been done by assessing the legislative, administrative and economic framework in New Member States and by analysing real business cases in companies. The empirical showcase business impact studies are at the same time of interest for companies of EU-15 states, other European countries who may implement the regulation, and even for exporters of raw materials and chemicals outside Europe, who will also have to comply with REACh if they market in the European Community. The results give no indications that REACh adoption will bring significant drawbacks to companies in the NMS. The emerging regulation will bring challenges for individual companies, especially for small and medium-sized ones, but for the European chemical industry as a whole, there is no question that it will be able to cope with REACh burdens without losing its global competitiveness. 相似文献
45.
46.
Kraigher H Al Sayegh Petkovsek S Grebenc T Simoncic P 《Environmental monitoring and assessment》2007,128(1-3):31-45
Mycorrhiza is the main spatial and temporal linkage between different constituents in a forest ecosystem. The functional compatibility
and stress tolerance of ectomycorrhizal types is species specific, and therefore the information on the ectomycorrhizal community
structure can add to the understanding of processes in forest ecosystems and can also be applied as tools for bioindication
of pollution stress in forest soils. We have studied the effects of pollution (N and S) on trees and forest soils by: (1)
quantification of ECM types diversity as in situ indicators in forest stands, (2) determination and quantification of pollution-sensitive or -insensitive ECM types as passive
monitors, (3) root growth and development of ECM on nonmycorrhizal spruce seedlings, planted at the studied sites (active
monitors), and (4) ECM infection (a bioassay based on mycorrhizal inoculum potential) of seedlings in an experimental set-up
as ex situ testers. ECM species richness for Norway spruce trees (Picea abies) showed higher values in unpolluted sites than in polluted ones, while the differences were not significant for European
beech trees (Fagus sylvatica). As pollution-sensitive or -insensitive ECM species in spruce forests, we suggest Hydnum rufescens (sensitive) and Paxillus involutus (unsensitive). Mycorrhizal potential in Norway spruce seedlings as a bioassay for soil N and S pollution was effective, and
is suggested as an additional, standardized and widely comparable system in bioindication of soil pollution. 相似文献
47.
Paoletti E Contran N Manning WJ Castagna A Ranieri A Tagliaferro F 《Environmental pollution (Barking, Essex : 1987)》2008,155(3):464-472
Treatments with ethylenediurea (EDU) protect plants from ozone foliar injury, but the processes underlying this protection are poorly understood. Adult ash trees (Fraxinus excelsior), with or without foliar ozone symptoms in previous years, were treated with EDU at 450ppm by gravitational trunk infusion in May-September 2005 (32.5ppmh AOT40). At 30-day intervals, shoot growth, gas exchange, chlorophyll a fluorescence, and water potential were determined. In September, several biochemical parameters were measured. The protective influence of EDU was supported by enhancement in the number of leaflets. EDU did not contribute its nitrogen to leaf tissue as a fertiliser, as determined from lack of difference in foliar N between treatments. Both biochemical (increase in ascorbate-peroxidase and ascorbic acid, and decrease in apoplastic hydrogen peroxide) and biophysical (decrease in stomatal conductance) processes regulated EDU action. As total ascorbic acid increased only in the asymptomatic trees, its role in alleviating O(3) effects on leaf growth and visible injury is controversial. 相似文献
48.
The distribution of Fe, Zn, Cu, Cd, Mn, Pb, and Ni in the organs and tissues (kidneys, liver, lungs, brain, heart, muscles, and feathers) of the European black vulture (Aegypius monachus) was studied. It was shown that heavy metals were not responsible for the mass mortality of these birds in southern Primorye in the winter of 2001–2002. The level of pollution with heavy metals of the range of European black vultures wintering in this region (northern China and western Mongolia) may be regarded as insignificant. 相似文献
49.
Zhongxiang Zhang 《Mitigation and Adaptation Strategies for Global Change》2007,12(2):203-217
The East-West Center convened the international conference on climate policy in Honolulu, Hawaii, on September 4–6, 2003. Sponsored by the Dutch Ministry of Housing, Spatial Planning and the Environment, the Japanese Ministry of the Environment, Industrial Technology Research Institute (Taiwan), and Institute for Global Environmental Strategies (Japan), this major event covered almost every important issue and featured perspectives from the most important parties and stakeholders in formulating and implementing climate policies and taking international climate negotiations further. It brought together a remarkable cross-section of world opinion on climate policy after Kyoto. This report provides a summary of each presentation and highlights discussions organized under the following six session headings: Session 1: Climate Change in Focus – From Science to Policy; Session 2: U.S. Climate Policy and Perspectives; Session 3: European Union Climate Policy and Perspectives; Session 4: Challenges for other Major Industrialized Countries; Session 5: Issues Related to Developing Countries; and Session 6: Panel Discussions: Where Do We Go from Here?. 相似文献
50.
Arseny Tsvey Victor N. Bulyuk Vlad Kosarev 《Behavioral ecology and sociobiology》2007,61(11):1665-1674
How migratory birds decide when to leave a stopover site is important to the understanding of bird migration strategies. Our
study looks at how body condition and the weather affect the decision to depart on nocturnal migratory flight. During two
autumn migration seasons (2002–2003), we radio tracked 51 first-year European robins, Erithacus rubecula, at a stopover site on the Courish Spit (Eastern Baltic) from the first day after landing until their migratory departure.
The tagged robins stopped over for 1–14 days. There was no clear relationship between stopover duration and energetic condition
on arrival. Weather conditions (wind, precipitation, and cloud cover) on departure differed measurably between years. In 2002,
robins took off mainly under following winds and clear skies. In 2003, there were mainly light head winds and partially cloudy
or overcast skies. This could be explained by the year-specific role of weather factors in making the decision to depart.
In both years, robins making short (1–2 days) stopovers took off in more varied weather situations than those individuals
with long stopovers. This suggests that robins from the former group were more inclined to continue with migration than longer-stay
birds that, apart from re-fuelling, could be waiting for favourable weather. The lack of a relationship between stopover duration
and body condition and some departures under unfavourable weather conditions suggest that endogenous spatiotemporal programmes
may play an important role in controlling stopover duration in robins. 相似文献