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91.
92.
生态建设本质和能力核心就是生产要素筹集配置能力和工程技术能力,因而生态建设受人力资源素质状态影响极大。本文深刻揭示生态建设人力资源规律和时空动态,对人力资源在生态建设角色、地位、作用、特征、人力资源的属性,对人力资源开发的影响因素、难点、重点、策略和措施等予以深刻而独到剖析;为各级政府、企业事业单位、社会团体从事生态建设人力资源开发,培养高素质生态建设活动组织者、指挥者、经营者和大量实用型技术人才提供依据和指导。  相似文献   
93.
A column leaching study was carried out over a period of 77 days to determine the changes in the chemistry of an acid soil and of the corresponding leachates after the addition of an anaerobic sludge (equivalent to 69 Mg DW ha−1). By the end of the experiment, the addition of the sludge to the soil had induced an increase in soil pH (from pH 3.6–4.0 to pH 4.1–4.8), in spite of the pronounced decrease in pH detected in the leachates by day 18 of the experiment. The decrease in pH (down to pH 3.3) occurred at the same time as leachate SO4 and Fe peaked. Once the acidification attributed to sulphide oxidation ceased, the “liming effect” of the sludge became evident and counteracted further proton production – such as that associated with oxidation of NH4 – at least for the duration of the study. Concentrations of Zn, Cd, Ni, and to a lesser extent, Pb in leachates displayed pulses at the beginning of the experiment (first 12 days), whereas the concentration of Cu followed a more irregular pattern; the concentrations of these metals never surpassed the European threshold values for drinking water. In contrast, concentrations of NO3, Mn, and Cr in leachates had increased by the end of the experiment – in parallel with an increase in dissolved organic C (DOC) – and surpassed the European threshold for drinking water. Mineralisation of native soil organic C (SOC) was enhanced by the addition of this N-rich residue, and the organic C mass balance at the end of the experiment was negative. Nitrogen mass balance, although positive, exhibited a loss of 77% of the N added to the system. The results obtained indicate that application of this sewage sludge to a soil with a pH < 5, at the loading rate used here, and without liming (i.e., non fulfilment of the requirements of the present European Directive) may pose a risk in terms of groundwater contamination.  相似文献   
94.
Fenton's pre-treatment of mature landfill leachate   总被引:20,自引:0,他引:20  
Lopez A  Pagano M  Volpe A  Di Pinto AC 《Chemosphere》2004,54(7):1005-1010
The aim of this study was to check the effectiveness of the Fenton's reagent (Fe2+ + H2O2 + H+) for the pre-treatment of a municipal landfill leachate with the objective of improving its overall biodegradability, evaluated in terms of BOD5/COD ratio, up to a value compatible with biological treatment. The leachate came from a municipal sanitary landfill located in southern Italy and the average values of its main parameters were: pH=8.2; COD=10,540 mgl(-1); BOD5=2,300 mgl(-1); TOC=3,900 mgl(-1); NH4-N=5210 mgl(-1); conductivity=45,350 microScm(-1); alkalinity=21,470 mgl(-1) CaCO3. The effect of initial pH value on the pre-treatment effectiveness was evaluated by titrating the amount of acidic by-products formed. The extent of leachate oxidation was monitored and controlled by both pH and redox potential measurements. The best operational conditions for achieving the desired goal (i.e., BOD5/COD> or =0.5) resulted: Fe2+=275 mgl(-1); H2O2=3,300 mgl(-1); initial pH=3; reaction time=2 h. At the end of the Fenton's pre-treatment, in order to permit a subsequent biological treatment, residual ferric ions were removed increasing the pH up to 8.5 by adding 3 gl(-1) of Ca(OH)2 and 3 mgl(-1) of a cationic polyelectrolyte, the latter as an aid to coagulation. This final step also resulted in a further modest removal of residual COD due to co-precipitation phenomena.  相似文献   
95.
固体火箭发动机沿海环境适应性分析   总被引:3,自引:1,他引:2  
为提高导弹武器环境适应性,针对沿海地区的气候环境特点,分析了高温、高湿、湿热、盐雾、霉菌和辐射等典型环境条件对固体火箭发动机薄弱环节的影响,结合研制和作战使用的实际,提出了改进导弹武器装备沿海环境适应性的方法.  相似文献   
96.
Journal of Material Cycles and Waste Management - The polysaccharide chitin (CHIT), extracted mainly from exoskeletons of crustaceans, can be obtained from shrimp fishery waste. It is the source of...  相似文献   
97.
Cemeteries and crematoria are the main funeral ways used in the world nowadays. It is a little-studied segment in the present days, mainly as for the possible environmental impacts in the environment, such as those derived from dental amalgam, prostheses, and dioxins, among other. This article aimed to identify the environmental impacts caused by cemeteries and crematoria and to point out new trends in funeral processes such as freeze-drying and alkaline hydrolysis. The study is justified due to the large part of the Brazilian population that do not know the environmental impacts caused by cemeteries and crematoria, as well as to bring information about the new processes. For that, a research was carried out with 400 people. The main results show that among all the funeral processes, the new freeze-drying process was opted by 33% of the sample. We also identified that the main reasons for choosing the funeral process were less environmental impact (28%), no after-death expenses (grave payment) (16.1%), and the possibility of putting away or throwing away the remains wherever you want (14.9%). Finally, new funeral processes were well accepted by the Brazilian population—those who were interviewed—due to their benefits.  相似文献   
98.
99.
Abstract

The fulvic acid (fua) fractions of two samples of composted solid wastes [urban (urfua) and livestock (lsfua) wastes], commercialized to be used in agriculture as organic correctives or fertilizers, were analyzed for their affinity towards Cu(II) at pH=6. Molecular fluorescence spectroscopy (synchronous mode) was used to monitor the quenching caused by the complexation upon addition of Cu(II) to fua. Spectral data were preprocessed by a chemometric self‐modeling mixture analysis method (SIMPLISMA) to detect the number of different types of fluorescent binding sites that exist in each fua, their spectra and the corresponding quenching profiles [fluorescence intensity as function of the total Cu(II) concentration]. From the analysis of the quenching profiles, the amount of binding sites (Cl) and the corresponding conditional stability constants (K') were calculated. Both fua samples have approximately Cl = 0.21 mmol/g and the logarithms of K’ are 4.21(3) and 4.51(8), respectively for urfua and lsfua. The differences detected between these fua samples and those extracted from natural soils can be attributed mainly to the relatively small humification extent of the present anthropogenic fua samples.  相似文献   
100.
Although melanin is the most common pigment in animal integuments, the adaptive function of variation in melanin-based coloration remains poorly understood. The individual fitness returns associated with melanin pigments can be variable across species as these pigments can have physical and biological protective properties and genes involved in melanogenesis may vary in the intensity of pleiotropic effects. Moreover, dark and pale coloration can also enhance camouflage in alternative habitats and melanin-based coloration can be involved in social interactions. We investigated whether darker or paler individuals achieve a higher fitness in birds, a taxon wherein associations between melanin-based coloration and fitness parameters have been studied in a large number of species. A meta-analysis showed that the degree of melanin-based coloration was not significantly associated with laying date, clutch size, brood size, and survival across 26 species. Similar results were found when restricting the analyses to non-sexually dimorphic birds, colour polymorphic and monomorphic species, in passerines and non-passerines and in species for which inter-individual variation in melanism is due to colour intensity. However, eumelanic coloration was positively associated with clutch and brood size in sexually dimorphic species and those that vary in the size of black patches, respectively. Given that greater extent of melanin-based coloration was positively associated with reproductive parameters and survival in some species but negatively in other species, we conclude that in birds the sign and magnitude of selection exerted on melanin-based coloration is species- or trait-specific.  相似文献   
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