Environmental Science and Pollution Research - Aedes aegypti and Culex quinquefasciatus are vectors of diseases that constitute public health problems. The discovery of products capable of... 相似文献
Microplastics have recently become a major environmental issue due to their ubiquitous distribution, uncontrolled environmental occurrences, small sizes and long lifetimes. Actual remediation methods include filtration, incineration and advanced oxidation processes such as ozonation, but those methods require high energy or generate unwanted by-products. Here we tested the degradation of fragmented, low-density polyethylene (LDPE) microplastic residues, by visible light-induced heterogeneous photocatalysis activated by zinc oxide nanorods. The reaction was monitored using Fourier-transform infrared spectroscopy, dynamic mechanical analyser and optical imaging. Results show a 30% increase of the carbonyl index of residues, and an increase of brittleness accompanied by a large number of wrinkles, cracks and cavities on the surface. The degree of oxidation was directly proportional to the catalyst surface area. A mechanism for polyethylene degradation is proposed.
Journal of Material Cycles and Waste Management - Material flow analysis (MFA) is a well-established tool for supporting decisions on nutrient management. This paper shows the importance of the... 相似文献
In this paper, we investigate the presence of economies of scale in the global iron-making industry for integrated steel plants, iron making being the first stage in the steel-making process. Iron making depends on basic commodities, such as iron ore, coke and various forms of energy, required in the operation of the blast furnace, which can be classified as essential inputs and used in fixed proportions to produce iron. A generalized Leontief cost function is estimated using panel data for 69 integrated plants, such a specification being appropriate for technologies with essential inputs that are used in fixed proportions in production. A significant scale effect is observed due to the existence of fixed costs and a linear dependence of the cost function on production. Under a simple linear cost function, a rough estimate of the breakeven scale of plant, where costs equal revenue, is 4.5 Mt per year. Competitiveness, as measured by the ratio of plant average cost per tonne to best practice cost per tonne, can be shown to be positively related to the scale of production as well as the cost of essential inputs. Therefore, low-cost producers are also often producers with low raw material costs and production levels below the estimated breakeven scale of operation. Labor costs, although significant, are comparatively less important as a driver towards low costs. 相似文献
This paper argues that important issues of sustainable development have been addressed through single-issue landscape plans, and that these plans have carried little weight within the land use decision-making process. A more consolidated approach, based on multi-function landscape plans, is proposed. After reviewing the range of plans which, in the UK, cover woodland, farmscapes, visual amenity, coasts, catchments and biodiversity, the case is made for an integrative plan capable of addressing natural resource issues at the landscape scale. The preliminary character of an integrative plan is outlined. Whilst landscape plans have a relatively weak basis for implementation, it is concluded that a sufficient range of powers is available to ensure some progress. 相似文献
The paper draws on an empirical study of two workshops in which the issues that arise from the use of geographic information systems (GIS) as a planning tool in public participation settings were explored by local residents who take an active interest in local planning matters in their London borough. The paper demonstrates how issues concerned with the democratization of GIS and public participation GIS (PPGIS) informed the structure and conduct of the workshops and the qualitative analysis of the workshop discussions. Key themes raised by participants included: the potential of PPGIS as a means of extending knowledge networks; issues of data ownership and the responsiveness of data providers to public concerns; and the role that institutional norms and practices play in democratizing information availability and the transparency of the decision-making process. The paper concludes that the potential of PPGIS as a planning tool cannot be separated from public concerns about the legitimacy of the planning process or local government. 相似文献