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Martin Pichler Georg Guggenberger Robert Hartmann Wolfgang Zech 《Environmental science and pollution research international》1996,3(1):24-31
The behavior of 20 PAH in the organic layers of a L mull, an Of mull and a mor was assessed by a combined approach of a soil
profile study, and the analysis of particle-size separates. Increasing PAH concentrations with depth in the mor profile (L,
866 μg kg−3; Of, 2902 μg kg−1; Oh, 10489 ug kg−1) were assigned to selective enrichment during organic matter decomposition. PAH were further highly enriched within the finer
separates. For the L horizons, significant positive correlations were established between the enrichment of individual PAH
(as observed from the decomposition gradient between the >2-mm fraction and the < 0.05-mm fraction), and the KOW for each compound. The slope of the regression line, m, described the degree of differentiation between low- and high-molecular
PAH during litter decomposition. Since m was greatest in the most biologically active humus type (L mull, 0.33) and smallest
in the most inactive (mor, 0.20), microbial breakdown was assumed as the dominating process for this differentiation. The
results also indicated that decomposition processes had already taken place in the L horizons, leading to morphological and
chemical changes of organic matter, and to an enrichment of high molecular PAH. 相似文献
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576.
Wolfgang K. H. Kinzelbach 《Environmental management》1981,5(1):69-77
In most industrialized countries, environmental standards exist which prescribe the maximum allowable man-made increase in water temperature of a river. Together with flowrate and weather conditions, these standards determine the rate at which waste heat may be discharged into a river at any moment. Power generating stations with variable cooling systems can adjust their heat discharge into the river in compliance with environmental standards and by doing so exert an influence on power generation capacity. In this paper, a scheme is developed that allows a chain of power stations discharging into the same river to operate their cooling systems such that the output of total electricity is maximized and water temperature standards are accomodated. The optimum balance between stations is determined through dynamic programming. From the results of a simulation model using historical data, simple decision rules for day-to-day operation are abstracted. These rules are based solely on the river flow rates at each power station. 相似文献
577.
An experimental group of homing pigeons (Columba livia f. domestica) learned to associate food with a magnetic anomaly produced by bar magnets that were fixed to the bowl in which they received
their daily food ration in their home loft; the control group lacked this experience. Both groups were trained to search for
two hidden food depots in a rectangular sand-filled arena without obvious visual cues; for the experimental birds, these depots
were also marked with three 1.15 × 106 μT bar magnets. During the tests, there were two food depots, one marked with the magnets, the other unmarked; their position
within the arena was changed from test to test. The experimental birds searched within 10 cm of the magnetically marked depot
in 49% of the test sessions, whereas the control birds searched there in only 11% of the sessions. Both groups searched near
the control depot in 11 and 13% of the sessions, respectively. The significant preference of the magnetically marked food
depot by the experimental birds shows that homing pigeons cannot only detect a magnetic anomaly but can also use it as a cue
for locating hidden food in an open arena. 相似文献
578.
Azhar Abbas Muhammad Ajaz Hussain Muhammad Amin Muhammad Sher Muhammad Nawaz Tahir Wolfgang Tremel 《环境科学学报(英文版)》2015,37(11):51-58
Chemically modified pullulan was evaluated for its sorption efficiency and selectivity to remove cadmium(Cd) from spiked high-hardness groundwater(GW). Pullulan esterified with succinic anhydride using dimethylaminopyridine showed a fairly high degree of substitution value as confirmed by1 H NMR spectroscopy. Pullulan succinate(Pull-Suc) was converted into the sodium salt(Pull-Suc-Na). The effect of contact time(5–200 min) and p H(2–8) on Cd-uptake by the sorbent(Pull-Suc-Na) was investigated. The sorbent showed more than 90% Cd-removal in first 15 min from distilled water(DW) and GW solution,respectively. Comparison of Pull-Suc-Na with other polysaccharidal sorbents suggested its high efficiency(DW 476.2 mg/g and GW 454.5 mg/g) and selectivity for the removal of Cd by an ion exchange mechanism, which is further supported by the negative Gibbs free energy values calculated from Langmuir isotherms. A Langmuir isotherm kinetic model provided the best fit for the sorption of Cd using Pull-Suc-Na. The sorbent showed a negligible decrease in Cd-uptake over three regeneration cycles. The thermal stability testing of the sorbents indicated that Pull-Suc-Na(sorbent) is more stable than Pull-Suc. 相似文献
579.
Recent Industrial Applications of Lignin: A Sustainable Alternative to Nonrenewable Materials 总被引:10,自引:0,他引:10
Lignin represents a vastly under-utilized natural polymer co-generated during papermaking and biomass fractionation. Different types of lignin exist, and these differ with regard to isolation protocol and plant resource (i.e., wood type or agricultural harvesting residue). The incorporation of lignin into polymeric systems has been demonstrated, and this depends on solubility and reactivity characteristics. Several industrial utilization examples are presented for sulfur-free, water-insoluble lignins. These include materials for automotive brakes, wood panel products, biodispersants, polyurethane foams, and epoxy resins for printed circuit boards. 相似文献