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961.
Periodic assessment of progress toward established policy goals is crucial to understanding whether the applied efforts are effective. In Europe, the Water Framework Directive (WFD) adopted in year 2000 set ambitious environmental objectives to be achieved by the end of 2015 through the implementation of Integrated Water Resources Management (IWRM) principles. While at this stage it is premature to measure the impact of this Directive in terms of environmental outcomes, it is nonetheless important to develop indicators in order to monitor whether water management practices throughout Europe are aligning towards IWRM. This article presents the methodological development of the Water and Wetland Index, a comparative water policy assessment by environmental NGOs that was carried out in 2002–2003, and highlights the interest of repeating it in 2015, when the first WFD planning cycle will be completed.  相似文献   
962.
The structure of the floodplain forests of the Middle Ebro River (NE Spain) was examined at patch and landscape scales along a three-step chronosequence defined according to the extent of flow regulation-induced hydrogeomorphic changes, with the ultimate purpose of producing baseline information to guide through management and restoration plans. At patch scale, a total of 6,891 stems within 39 plots were registered for species, diameter and health status. The stem density, size class distribution, canopy dieback and mortality were further compared by means of non-parametric tests. At landscape scale, the temporal evolution of the area occupied by forest stands of different ages in the floodplain along the chronosequence was evaluated using four sets of aerial photographs dated in 1927, 1957, 1981 and 2003. The within-patch structure of pioneer forests (<25–30 years old) was characterized by dense and healthy populations of pioneer species (Populus nigra, Salix alba and Tamarix spp.), but the area occupied by these forest types has progressively decreased (up to 37%) since the intensification of river regulation (ca. 1957). In contrast, non-pioneer forests (>25–30 years old) were characterized by declining and sparse P. nigraS. albaTamarix spp. stands, where late-seral species such as Ulmus minor and Fraxinus angustifolia were frequent, but only as small-size stems. At landscape scale, these type of senescent forests have doubled their surface after river regulation was intensified. Populus alba only appeared in the oldest plots recorded (colonized before 1957), suggesting sexual regeneration failure during the last five decades, but usually as healthy and dense stands. Based on these findings, measures principally aimed at recovering some hydrogeomorphic dynamism are recommended to guarantee the self-sustainability of the floodplain forest ecosystem.  相似文献   
963.
This work focused on anaerobic biodegradation of blends composed of glycerol-plasticized polyvinyl alcohol (PVA) and biopolymer (starch, gellan, xanthan) in an aqueous environment, after inoculation with digested activated sludge from a municipal wastewater treatment plant. Glycerol degradability is comparable to degradability of used modifying agents. Modifying agents added in the 20–40 wt% range proportionally increased biodegradation degree (Dt) calculated from balance of transformed carbon in the system. Biodegradation degree of polysaccharides and glycerol attained 95% and over. For PVA it was only 6.5% (in breakdown times up to 500 h). Content of polysaccharides favorably affects biodegradation degree of polyvinyl alcohol blends, but at the expense of reduced mechanical properties of resultant products.  相似文献   
964.
The effect of lignosulfonate on poly(3-hydroxybutyrate-co-3-hydroxyvalerate), PHBV, was studied by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The PHBV/lignosulfonate samples were prepared by melt mixing in an internal mixer. SEM showed that PHBV/lignosulfonate samples present a cracked surface that is more intense in mixtures with high lignosulfonate proportions. According to DSC, melting and glass transition temperatures of the PHBV matrix decrease with lignosulfonate addition. The same effect was observed for melting enthalpies (ΔHm), which indicates a decrease of crystallinity. TGA showed that thermal stability of PHBV/lignosulfonate samples was shifted to lower temperatures, which indicates the existence of an interaction between the thermal decomposition processes of PHBV and lignosulfonate.  相似文献   
965.
Riparian forests (RF) growing along streams, rivers and lakes comprise more than 2% of the forest area in the Nordic countries (considering a 10 m wide zone from the water body). They have special ecological functions in the landscape. They receive water and nutrients from the upslope areas, are important habitats for biodiversity, have large soil carbon stores, but may emit more greenhouse gases (GHG) than the uplands. In this article, we present a review of the environmental services related to water protection, terrestrial biodiversity, carbon storage and greenhouse gas dynamics provided by RF in the Nordic countries. We discuss the benefits and trade-offs when leaving the RF as a buffer against the impacts from upland forest management, in particular the impacts of clear cutting. Forest buffers are effective in protecting water quality and aquatic life, and have positive effects on terrestrial biodiversity, particularly when broader than 40 m, whereas the effect on the greenhouse gas exchange is unclear.  相似文献   
966.
A common characteristic of carbon capture and storage systems is the important energy consumption associated with the CO2 capture process. This important drawback can be solved with the analysis, synthesis and optimization of this type of energy systems. The second law of thermodynamics has proved to be an essential tool in power and chemical plant optimization. The exergy analysis method has demonstrated good results in the synthesis of complex systems and efficiency improvements in energy applications.In this paper, a synthesis of pinch analysis and second law analysis is used to show the optimum window design of the integration of a calcium looping cycle into an existing coal power plant for CO2 capture. Results demonstrate that exergy analysis is an essential aid to reduce energy penalties in CO2 capture energy systems. In particular, for the case of carbonation/calcination CO2 systems integrated in existing coal power plants, almost 40% of the additional exergy consumption is available in the form of heat. Accordingly, the efficiency of the capture cycle depends strongly on the possibility of using this heat to produce extra steam (live, reheat and medium pressure) to generate extra power at steam turbine. The synthesis of pinch and second law analysis could reduce the additional coal consumption due to CO2 capture 2.5 times, from 217 to 85 MW.  相似文献   
967.
Since the damage suffered by buildings as a consequence of explosions usually affect the people inside them, it is important to take it into account when performing consequence analysis. The aim of this paper is to provide a methodology to estimate consequences to buildings from pressure waves produced by spherical vessel burst. This is done by combining characteristic overpressure–impulse–distance curves [González Ferradás, E., Diaz Alonso, F., Sanchez Perez, J.F., Miñana Aznar, A., Ruiz Gimeno, J. and Martinez Alonso, J., 2006, Characteristic overpressure–impulse–distance curves for vessel burst, Process Safety Progress, 25(3): 250–254] with PROBIT equations. The main advantage of this methodology is that it allows an overview of all the magnitudes involved, as damage is shown in the same graph as the overpressure, impulse and distance. In this paper diagrams and equations are presented to determine minor damage to buildings (broken windows, displacement of doors and window frames, tile displacement, etc.), major structural damage (cracks in walls, collapse of some walls) and collapse (the damage is so extensive that the building is partially or totally demolished).  相似文献   
968.
Water quality in streams is dependent on landscape metrics at catchment and wetland scales. A study was undertaken to evaluate the correlation between landscape metrics, namely patch density and area, shape, heterogeneity, aggregation, connectivity, land-use ratio, and water quality variables (salinity, nutrients, sediments, alkalinity, other potential pollutants and pH) in the agricultural areas of a semiarid Mediterranean region dominated by irrigated farmlands (NE Spain). The study also aims to develop wetland construction criteria in agricultural catchments. The percentage of arable land and landscape homogeneity (low value of Simpson index) are significantly correlated with salinity (r(2) = 0.72) and NO(3)-N variables (r(2) = 0.49) at catchment scale. The number of stock farms was correlated (Spearman's corr. = 0.60; p < 0.01) with TP concentration in stream water. The relative abundance of wetlands and the aggregation of its patches influence salinity variables at wetland scale (r(2) = 0.59 for Na(+) and K(+) concentrations). The number and aggregation of wetland patches are closely correlated to the landscape complexity of catchments, measured as patch density (r(2) = 0.69), patch size (r(2) = 0.53), and landscape heterogeneity (r(2) = 0.62). These results suggest that more effective results in water quality improvement would be achieved if we acted at both catchment and wetland scales, especially reducing landscape homogeneity and creating numerous wetlands scattered throughout the catchment. A set of guidelines for planners and decision makers is provided for future agricultural developments or to improve existing ones.  相似文献   
969.
Sulfate-reducing bacteria (SRB) that could grow on modified Postgate C medium (PC) containing chromium(VI) were isolated from industrial wastewaters and their chromium(VI) reduction capacities were investigated as a function of changes in the initial pH values, chromium, sulfate, NaCl and reactive dye concentrations. The optimum pH value at 50 mg l(-1) initial chromium(VI) concentration was determined to be 8. Chromium(VI) reduction by SRB was investigated at 22.7-98.4 mg l(-1) initial chromium(VI) concentrations. At the end of the experiments, the mixed cultures of SRB were found to reduce within 2-6 days more than 99% of the initial chromium(VI) levels, which ranged from 22.7 to 74.9 mg l(-1). The effects of the initial 0-9.0 g l(-1) concentrations of disodium sulfate and 0-6% (w/v) concentrations of NaCI to chromium reduction showed that the lowest concentrations of sulfate and NaCI were the best for chromium reduction in the PC medium including 50 mg l(-1) chromium(VI). Chromium(VI) reduction in 50 mg l(-1) and 25-100 mg l(-1) Remazol Blue, Reactive Black B or Reactive Red RB containing media were also investigated. In the experiments, 25-30% of the initial dye concentrations and 95% of the chromium(VI) was removed from the medium at the end of 72-h and 24-h incubation periods, respectively.  相似文献   
970.
Locating an undesirable facility is a sophisticated problem, for the evaluation procedures involve several objectives and the solution to the problem calls for some compromises to be made between probable conflicting criteria. This paper addresses the problem of undesirable facility location selection using the analytic network process (ANP), a multi-criteria decision-making technique. The ANP technique enables us to consider both qualitative and quantitative criteria as well as the interdependencies and feedbacks. A number of criteria (benefits, opportunities, costs and risks) and their sub-criteria are considered for siting a new facility with which this study has dealt. The questions of what criteria would be considered and what the interdependencies between these criteria and their weights would be were discussed and determined via interviews with some competent authorities of the Istanbul Municipality and of two environmental organizations. Four representative locations were evaluated and the most convenient one was selected. This was followed by the sensitivity analyses of the results.  相似文献   
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