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941.
942.
943.
M. Demarcke J.-F. Müller N. Schoon H. Van Langenhove J. Dewulf E. Joó K. Steppe M. Šimpraga B. Heinesch M. Aubinet C. Amelynck 《Atmospheric environment (Oxford, England : 1994)》2010,44(27):3261-3268
Monoterpenoid emissions from Fagus sylvatica L. trees have been measured at light- and temperature-controlled conditions in a growth chamber, using Proton Transfer Reaction Mass Spectrometry (PTR-MS) and the dynamic branch enclosure technique.De novo synthesized monoterpenoid Standard Emission Factors, obtained by applying the G97 algorithm (Guenther, 1997), varied between 2 and 32 μg gDW?1 h?1 and showed a strong decline in late August and September, probably due to senescence.The response of monoterpenoid emissions to temperature variations at a constant daily light pattern could be well reproduced with a modified version of the MEGAN algorithm (Guenther et al., 2006), with a typical dependence on the average temperature over the past five days.The diurnal emissions at constant temperature showed a typical hysteretic behaviour, which could also be adequately described with the modified MEGAN algorithm by taking into account a dependence on the average light levels experienced by the trees during the past 10–13 h.The impact of the past light and temperature conditions on the monoterpenoid emissions from F. sylvatica L. was found to be much stronger than assumed in previous algorithms.Since our experiments were conducted under low light intensity, future studies should aim at confirming and completing the proposed algorithm updates in sunny conditions and natural environments. 相似文献
944.
945.
Atmospheric polycyclic aromatic hydrocarbons in remote European and Atlantic sites located above the boundary mixing layer 总被引:1,自引:1,他引:0
Barend Leendert Van Drooge Pilar Fernández Joan O. Grimalt Evzen Stuchlík Carlos J. Torres García Emilio Cuevas 《Environmental science and pollution research international》2010,17(6):1207-1216
Background, aim and scope
Ambient air concentrations of polycyclic aromatic hydrocarbons (PAH) were determined at five elevated mountain sites on the European continent and the Atlantic Ocean. All sites can be considered remote background areas since they are situated above the timberline and they lack local emission sources of these compounds. 相似文献946.
O. Sracek M. Mihaljevič B. Kříbek V. Majer J. Filip A. Vaněk V. Penížek V. Ettler B. Mapani 《Environmental monitoring and assessment》2014,186(8):4891-4903
The mine tailings at Kombat, in semiarid northeastern Namibia, were investigated by the combination of solid-phase analyses, mineralogical methods, leaching tests, and speciation modeling. Dissolution of the most abundant primary sulfides, chalcopyrite and galena, released copper and lead which were adsorbed onto ferric oxyhydroxides or precipitated in the form of malachite, Cu2CO3(OH)2, and cerussite, PbCO3, respectively. Arsenic released from arsenopyrite was incorporated into ferric oxyhydroxides. Based on sequential extraction and 57Fe Mössbauer spectroscopy, a large amount of ferric iron is present as low solubility hematite and goethite formed rapidly (<10 years) under warm semiarid climatic conditions, and arsenic in these phases is relatively tightly bound. It seems that Cu and especially Pb in carbonate minerals represent a more serious environmental risk. Immobilization of As in hematite has implications for other mining sites in regions with similar climatic conditions because this process results in long-term immobilization of As. 相似文献
947.
Outbound offending: The journey to crime and crime sprees 总被引:1,自引:0,他引:1
Studies on crime and mobility primarily focus on local crime patterns. The city has long played an important role, whether analysing the offence or the offender. This paper goes beyond city boundaries and discusses ‘outbound offenders’, whose crime trips start in a city, but end outside. It is argued that a substantial proportion of crime trips follow this pattern, indicating that areas other than cities also provide interesting opportunities for property crime. We link outbound offending to a number of features that may explain crime travelling, including the target’s features and offender/offence features. We find that outbound offending mostly occurs towards affluent target regions and near motorways, as such confirming findings from previous research. We also find crime sprees to be indicative for mobile offending. Thus, mobile property offenders tend to compensate for travelled distances, not only by targeting affluent areas and using fast transportation means, but also by committing several successive offences, hereby reducing their relative transportation cost for each offence. 相似文献
948.
Development of Proteinous Bioplastics Using Bloodmeal 总被引:1,自引:0,他引:1
Casparus J. R. Verbeek Lisa E. van den Berg 《Journal of Polymers and the Environment》2011,19(1):1-10
The aim of this work was to investigate the use of bloodmeal as a thermoplastic biopolymer. Processing required water and chemical additives to perform three main functions: breaking covalent cross-links using sodium sulfite (SS), sodium dodecyl sulfate and urea as processing aids, and evaporating some processing water to allow formation of new interactions to stabilize the final structure. Extrusion was only possible in the presence of SS and strongly influenced by water and urea content. It was found that once water had been removed, mechanical properties increased significantly, indicating the formation of new intermolecular forces. SDS was required for processing and consolidation, but, it may restrict formation of new intermolecular forces, if used in excessive quantities. Materials based on optimal additive levels had a tensile strength of 8 MPa, Young’s modulus of 320 MPa and toughness 1.6 MPa m½. 相似文献
949.
950.
Ana F. L. Godoi Eliza Y. Sawada Mary Rosa R. de Marchi René Van Grieken Ricardo H. M. Godoi 《Water, Air, & Soil Pollution: Focus》2009,9(3-4):163-169
The use of inks containing organic solvents by the offset printing process implies in the release of volatile organic compounds to the work environment. Many of these compounds such as benzene, toluene, ethylbenzene, and the xylene isomers (well known by the acronym BTEX) are extremely toxic. In this study, the BTEX concentrations were determined in two different printing plants that use distinct types of inks: the conventional and the so-called ecological, which is manufactured based on vegetal oil. Concentration ranges were 43–84, 15–3,480, 2–133, 5–459, and 2–236 μg m?3 for benzene, toluene, ethylbenzene, m?+?p-xylene, and o-xylene, respectively, for the conventional printing plant. At the ecological printing plant, concentration ranges were below limit of detection (<LD)-31, <LD-618, <LD-1,690, <LD-10,500, <LD-3,360 μg m?3 for benzene, toluene, ethylbenzene, m?+?p-xylene, and o-xylene, respectively. BTEX concentrations are lower at the ecological printing environment than in the conventional, where mineral oil-based inks are used. However, the worker who cleans the printing matrices is exposed to high concentrations of ethylbenzene and xylenes, due probably to the cleaning product’s composition (containing high amounts of BTEX). Although the BTEX concentrations found in both printing work environments were below the limits considered by the Brazilian Law for Activities and Unhealthy Operations (NR-15), the exposure to such vapors characterizes risk to the workers’ health for some of the evaluated samples, mainly the personal ones. 相似文献