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431.
Isaac R. Kaplan Shan-Tan Lu Hossein M. Alimi John MacMurphey 《Environmental Forensics》2013,14(3):231-248
Fingerprinting of hydrocarbon products requires high resolution differentiation of individual hydrocarbon compounds in any mixture. This requires the applications of various measuring techniques. In this paper, we have chosen the heavy hydrocarbons in fuels, lubricants and paving material as examples to discuss the methods for chemical characterization and differentiation. In the category most frequently termed "semi-volatile hydrocarbons" with boiling points from about 500°F to 1200°F or higher, there are several families of hydrocarbons, both natural and refined that are not easily distinguished by conventional EPA tests. Among the groups which we will use as examples are asphalts, hydraulic fluid, transmission oil, motor lubricating oils, heating oils, crude oil and coal. These hydrocarbon families are best studied using combined gas chromatography-mass spectrometry in full scan mode and characterizing various homologous series of hydrocarbons at known fragment ions. The hydrocarbon series providing the best information are: (1) N -alkanes; (2) iso-alkanes; (3) steranes; (4) terpanes; (5) polynuclear aromatic hydrocarbons; (6) aromatic steranes; and (7) specific polycyclic compounds. 相似文献
432.
The REDD+ (Reducing Emissions from Deforestation and Forest Degradation) partnership works to promote the reduction of greenhouse gas (GHG) emissions by protecting forests in developing countries through positive incentives. It is regarded as an essential component of the post‐2012 climate regime to stabilize GHG emissions and engage developing countries in worldwide mitigation endeavours. This study focuses on the gap between agricultural revenue and REDD+ compensation through the construction of several scenarios that explore the impacts of possible carbon price ranges.Three scenarios that reflect different potential policies are examined: (1) current carbon trading; (2) carbon trading with all forestry activities; and (3) carbon trading with all countries participating gradually over the coming decades. Data for developing the scenarios were obtained through a case study in central Kalimantan, Indonesia, by interrogating the potential for revenue by expanding agricultural land. The results indicate that REDD+ payments could not effectively compensate land users for their opportunity cost of deforestation, making it difficult for the governments to ensure that REDD+ money “reaches the ground” in terms of balancing the agricultural revenue of land users. 相似文献
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437.
张璐 《中国环境管理干部学院学报》2012,22(2):8-11
从行为参与、管理参与和环境意识三个方面阐述了当前环保事务参与中存在的性别差异问题;从社会结构的视角分析了性别化对环保参与现状的影响。针对存在的问题和制约因素,从社会系统、社会资源和环境意识三个方面提出发展建议。 相似文献
438.
通过分析当前社会需求,结合高职高专院校目前的教学模式,提出计算机应用专业的《JSP动态网站设计》课程的教学改革方案。在基于工作任务的lAPP(导入-分析-实践-项目)教学情境中,开展“课堂实训+虚拟公司+校外实训基地”三位一体的实践模式教学,同时,将对工作过程的考核纳入课程的整个考核体系之中,使学生在课程中能够获得真实的职业体验和完善的实践能力。 相似文献
439.
Effect of humic acids on physicochemical property and Cd(II) sorption of multiwalled carbon nanotubes 总被引:1,自引:0,他引:1
Zinc pyrithione is used as an antifouling agent. However, the environmental impacts of zinc pyrithione have recently been of concern. Zinc induces diverse actions during oxidative stress; therefore, we examined the effect of zinc pyrithione on rat thymocytes suffering from oxidative stress using appropriate fluorescent probes. The cytotoxicity of zinc pyrithione was not observed when the cells were incubated with 3 μM zinc pyrithione for 3 h. However, zinc pyrithione at nanomolar concentrations (10 nM or more) significantly increased the lethality of cells suffering from oxidative stress induced by 3 mM H2O2. The application of zinc pyrithione alone at nanomolar concentrations increased intracellular Zn2+ level and the cellular content of superoxide anions, and decreased the cellular content of nonprotein thiols. The simultaneous application of nanomolar zinc pyrithione and micromolar H2O2 synergistically increased the intracellular Zn2+ level. Therefore, zinc pyrithione at nanomolar concentrations may exert severe cytotoxic action on cells simultaneously exposed to chemicals that induce oxidative stress. If so, zinc pyrithione leaked from antifouling materials into surrounding environments would be a risk factor for aquatic ecosystems. Alternatively, zinc pyrithione under conditions of oxidative stress may become more potent antifouling ingredient. 相似文献
440.
Phytoavailability and geospeciation of cadmium in contaminated soil remediated by Rhodobacter sphaeroides 总被引:1,自引:0,他引:1
A microorganism was isolated from oil field injection water and identified as Rhodobacter sphaeroides. It was used for the remediation of simulated cadmium-contaminated soil. The phytoavailability of Cd was investigated through wheat seedling method to determine the efficiency of remediation. It was found that after remediation, the accumulation of Cd in wheat roots and leaves decreased by 67% and 53%, respectively. The Cd speciation in soil was determined with Tessier extraction procedure. It was found that the total Cd content in soil did not change during the experiments, but the geo-speciation of Cd changed remarkably. Among the five fractions, the concentration of exchangeable phases decreased by 27-46% and that of the phases bound to Fe-Mn oxides increased by 22-44%. The decrease of Cd accumulation in wheat showed significant positive correlation with the decrease of exchangeable phases. It could be concluded that the remediation of R. sphaeroides was carried out through the conversion of Cd to more stable forms. The decrease of sulfate concentration in supernatant indicated that the R. sphaeroides consumed sulfate. 相似文献