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961.
电解铝西部转移是大势所趋,再生有色金属的西部转移是目前行业内探讨的热门话题。但西部并不具备大规模发展再生有色金属产业的条件和基础。西部再生有色金属产业更多的是依赖内生性的发展。 相似文献
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964.
在对水泥生产线篦冷机尾气除尘进行分析的基础上,提出了电除尘改袋式除尘的必要性,可有效控制新型干法窑烟尘和粉尘的排放浓度;针对具体案例的使用结果进行了阐述。 相似文献
965.
Melissa A. Kenney Peter R. Wilcock Benjamin F. Hobbs Nicholas E. Flores Daniela C. Martínez 《Journal of the American Water Resources Association》2012,48(3):603-615
Kenney, Melissa A., Peter R. Wilcock, Benjamin F. Hobbs, Nicholas E. Flores, and Daniela C. Martínez, 2012. Is Urban Stream Restoration Worth It? Journal of the American Water Resources Association (JAWRA) 48(3): 603-615. DOI: 10.1111/j.1752-1688.2011.00635.x Abstract: Public investment in urban stream restoration is growing, yet little has been done to quantify whether its benefits outweigh its cost. The most common drivers of urban stream projects are water quality improvement and infrastructure protection, although recreational and aesthetic benefits are often important community goals. We use standard economic methods to show that these contributions of restoration can be quantified and compared to costs. The approach is demonstrated with a case study in Baltimore, Maryland, a city with a legal mandate to reduce its pollutant load. Typical urban stream restoration costs of US$500-1,200 per foot are larger than the cost of the least expensive alternatives for management of nitrogen loads from stormwater (here, detention ponds, equivalent to $30-120 per foot of restored stream) and for protecting infrastructure (rip-rap armoring of streambanks, at $0-120 per foot). However, the higher costs of stream restoration can in some cases be justified by its aesthetic and recreational benefits, valued using a contingent valuation survey at $560-1,100 per foot. We do not intend to provide a definitive answer regarding the worth of stream restoration, but demonstrate that questions of worth can be asked and answered. Broader application of economic analysis would provide a defensible basis for understanding restoration benefits and for making restoration decisions. 相似文献
966.
Anaerobic degradation of microcrystalline cellulose: kinetics and micro-scale structure evolution 总被引:1,自引:0,他引:1
The degradation kinetics and micro-scale structure change of microcrystalline cellulose during anaerobic biodegradation were investigated. A modified Logistic model was established to properly describe the kinetics, which showed good fitness and wide applicability for cellulose degradation. A maximum degradation rate of 0.14 g L−1 h−1 was achieved after cultivating for 51.5 h. This result was in good agreement with the scanning electron microscope and X-ray diffraction analysis. Channels of 400-500 nm size started to occur on the crystalline surface of cellulose at around the inflexion time. Accordingly, the crystallinity significantly decreased at this point, indicating a degradation of the crystalline structure zones by anaerobic bacteria. This study offers direct morphological evidence and quantitative analysis of the biodegradation process of cellulose, and is beneficial to a better understanding of the cellulose degradation mechanism. 相似文献
967.
Viau CM Cardone JM Guecheva TN Yoneama ML Dias JF Pungartnik C Brendel M Saffi J Henriques JA 《Chemosphere》2012,86(5):477-484
Tin or stannous (Sn2+) compounds are used as catalysts, stabilizers in plastic industries, wood preservatives, agricultural biocides and nuclear medicine. In order to verify the Sn2+ up-take and toxicity in yeast cells we utilized a multi-elemental analysis known as particle-induced X-ray emission (PIXE) along with cell survival assays and quantitative real-time PCR. The detection of Sn2+ by PIXE was possible only in yeast cells in stationary phase of growth (STAT cells) that survive at 25 mM Sn2+ concentration. Yeast cells in exponential phase of growth (LOG cells) tolerate only micro-molar Sn2+ concentrations that result in intracellular concentration below of the method detection limit. Our PIXE analysis showed that STAT XV185-14c yeast cells demonstrate a significant loss of intracellular elements such as Mg, Zn, S, Fe and an increase in P levels after 1 h exposure to SnCl2. The survival assay showed enhanced tolerance of LOG yeast cells lacking the low-affinity iron and zinc transporters to stannous treatment, suggesting the possible involvement in Sn2+ uptake. Moreover, our qRT-PCR data showed that Sn2+ treatment could generate reactive oxygen species as it induces activation of many stress-response genes, including SOD1, YAP1, and APN1. 相似文献
968.
Organochlorine pesticides are persistent lipophilic organic pollutants and tend to accumulate in growing plants. During growth, cork is in contact with the open air for long periods (9-12 years). Owing to the previous widespread use of organochlorine pesticides and their high persistence in the environment, there is a risk that residues of such pesticides may be present in cork.In this study, the concentrations of 14 organochlorine pesticides—all of which are indicators of environmental pollution—were analyzed in cork bark samples from three regions in Spain and one in Portugal. In addition, the concentrations of 2,4,6-trichlorophenol (TCP) and 2,4,6-trichloroanisole (TCA) were also analyzed.Our results show only very low concentrations of lindane, γ-HCH (<2.6 ng g−1) and its byproducts α-HCH (<3.5 ng g−1) and β-HCH (<0.6 ng g−1).Among the DDT and its metabolites, only two were found: p,p′-DDT was found in a cork sample from Extremadura (0.1 ng g−1) and p,p′-DDE was present at a maximum concentration of 2.9 ng g−1 in a cork sample from Castile-La Mancha. However, all concentrations were well below the legal limit established by Regulation (EC) No. 396/2005 (10 ng g−1 in foodstuffs). We can conclude, therefore, that the cork samples we studied complied with food safety standards. 相似文献
969.
The aim of the current study was to investigate the potential of an aquatic plant, the water hyacinth (Eichhornia crassipes) devoid rhizospheric bacteria, to reduce naphthalene (a polyaromatic hydrocarbon) present in wastewater and wetlands.The capability of sterile water hyacinth plants to remove naphthalene from water and wastewater was studied in batch systems. Water hyacinths enhance the removal of pollutants through their consumption as nutrients and also through microbial activity of their rhizospheric bacteria.Experimental kinetics of naphthalene removal by water hyacinth coupled with natural rhizospheric bacteria was 100% after 9 d. Plants, decoupled of rhizospheric bacteria, reduced naphthalene concentration up to 45% during 7 d. Additionally, naphthalene uptake by water hyacinth revealed a biphasic behavior: a rapid first phase completed after 2.5 h, and a second, considerably slower rate, phase (2.5-225 h). In conclusion, water hyacinth devoid rhizospheric bacteria reduced significantly naphthalene concentration in water, revealing a considerable plant contribution in the biodegradation process of this pollutant. 相似文献