High energy prices and the growing concern for “Peak Oil” have put energy analysis, once again, on the front burner. However, before speculating about possible roadmaps regarding our energy future, it would be wise to develop better quantitative analyses. This paper flags the existence of systemic epistemological flaws in the current use of aggregate energy indicators and presents an alternative approach capable of dealing with the issue of multiple dimensions and multiple scales. Starting from a critical appraisal of the aggregate indicator “Economic Energy Intensity” it shows that economic and biophysical variables are often correlated and that their value is determined by characteristics which can only observed across different levels and scales. Complex metabolic systems (systems that use energy to maintain and reproduce themselves) are operating simultaneously at different scales. This implies that changes in the characteristics of parts, defined at the local scale, and changes in the characteristics of the whole, defined at the large scale can only be obtained after establishing a scaling mechanism in the analysis. In order to deal with the issue of scale in energy accounting, we propose to make a distinction between three different categories: (i) primary energy sources (PES) - establishing a link between energy quantities and the associated requirement of biophysical gradients, at the large scale, on the interface black-box/context; (ii) energy carriers (EC) - defining the set of energy inputs required by technical devices for expressing useful functions, at the local scale, within the parts operating inside the black-box; (iii) end uses (EU) the set of functions to be expressed by society across hierarchical levels for reproducing itself. Finally, the paper presents examples of quantitative results obtained using an innovative method of analysis - Multi-Scale Integrated Analysis of Societal and Ecosystem Metabolism (MuSIASEM). We conclude that by using this new accounting method it is possible to generate a better understanding of external and internal constraints determining the desirability and viability of the metabolic pattern of societies. 相似文献
The traditional degradation of organic pollutants is based on the sacrifice of chemical or biological reagents. In this study, a purely physical technique was developed to break the chemical bonds and consequently decompose macromolecules in aqueous solution. Assisted with a high-speed mechanical blade, refined quartz sand grains with particularly sharp nanoscale edges can act as ‘nano-knives', which are able to cut the long chain of carboxymethyl cellulose(CMC, as a model molecule). High performance size exclusion chromatography measurements evidenced that the original CMC molecules(41,000 Da) were decomposed into a series of smaller molecules(460, 1000, 2200, 21,000, 27,000 and 31,000 Da). Consequently, the initial viscosity of the CMC solution(2 g/L) rapidly decreased by approximately 50% after 3 min treatment by the nano-knife materials along with the mechanical blade. Fourier transform infrared(FTIR) spectra indicated that the original functional groups were still present and new functional groups were not produced after shearing. The intensity of the main functional groupβ-1-4-glycosidic bond(wavenumber 1062 cm-1) was observed to markedly decrease after shearing. These results indicated that the long-chain CMC was cleaved into short-chain CMC. A degradation mechanism was proposed whereby the cutting force generated by the rapid motion of the nano-knives may be responsible for the breakage of β-1-4-glycosidic bonds in the macromolecular cellulose backbone. These results provide support for a potentially more affordable and environment-friendly strategy for physical-based decomposition of recalcitrant organic pollutants from aqueous solution without the need of chemical or biological reagents. 相似文献
Environmental Science and Pollution Research - Radon exhalation from soil and ores is among the most dangerous risks for the public health care. The impact becomes even more powerful when... 相似文献
Environmental Science and Pollution Research - A large amount of fresh tobacco waste with high water content are produced in farmland, and it may cause environmental pollution if it is not properly... 相似文献
Environmental Science and Pollution Research - To control the dust pollution caused by open-pit coal mining and reduce or avoid the secondary hazards of existing dust suppressants to the... 相似文献
Copper oxide nanoparticles (CuO NPs) have received considerable attention for their toxic effects on crops and potential application in agriculture. In order to investigate the biological effects of CuO NPs on plants, we exposed cucumber (Cucumis sativus) to two sizes of CuO NPs (510 nm, μCuO and 43 nm, nCuO). Results indicated that with concentration increased, the available Cu content in soil increased significantly. The addition of CuO NPs increased Cu content and other nutrient element (e.g., K, P, Mn, and Zn) content in plants. However, diverse particle sizes had different effects. The nCuO treatment had larger translocation factor, higher nutrient element content in fruits, and lower oxidative damage than μCuO treatment. Moreover, nCuO of 100 mg/kg could stimulate cucumber growth, while μCuO had no obvious effects on growth. Conclusively, CuO NPs could be used as copper fertilizer to supply copper to cucumber. The nCuO had better effects on improving the bioavailability of Cu and nutritional value of fruits. These results can help develop strategies for safe disposal of CuO NPs as agricultural fertilizer.