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51.
The ecological reaction of species on environmental factors can differ both, temporally and geographically. Therefore, bioindicator systems must be shown to remain accurate at different places and points of time. Extreme events pose challenges for testing this robustness, which has not yet been explored systematically. The unique opportunity of the extreme flooding of the river Elbe in August 2002 was used for such a test. The bioindicator system for mean groundwater depth during the vegetation period and annual duration of inundation in floodplains studied here was developed with data collected in 1999. Data from 2003 were used to analyse the dependence of the bioindication results on the humidity of the study plots and taxonomic group (plants, molluscs and carabid beetles). For the duration of inundation, the accuracy of bioindication in 2003 was similar to that in 1999, except for the medium‐humid and dry plots using molluscs as indicators. For groundwater depth, the accuracy of bioindication in 2003 was similar to that of the reference year except in the dry plots with significantly lower accuracy for all species groups. With a few exceptions, the bioindicator system is shown to be robust and to remain accurate in spite of an extreme flood event. In conclusion, the relevance of extreme events for the robustness of bioindicator systems differs between the indicated parameters and taxonomic groups. The results stress the need to take into account the limits of the working range and the occurrence of extreme events, when testing and applying bioindicator systems. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
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53.
There is increasing concern regarding the presence of unregulated trace organic chemicals in drinking water supplies that receive discharge from municipal wastewater treatment plants. In comparison to conventional and advanced drinking water treatment, riverbank filtration represents a low-cost and low-energy alternative that can attenuate total organic carbon (TOC) as well as trace organic chemicals (TOrC). This study examined the role of predominant redox conditions, retention time, biodegradable organic carbon, and temperature to achieve attenuation of TOC and TOrC through monitoring efforts at three full-scale RBF facilities in different geographic areas of the United States. The RBF systems investigated in this study were able to act as a reliable barrier for TOC, nitrogen, and certain TOrC. Temperature (seasonal) variation played an important role for the make-up of the river water quality and performance of the RBF systems. Temperatures of less than 10 °C did not affect TOC removal but resulted in diminished attenuation of nitrate and select TOrC.  相似文献   
54.
Low ambient pressures at elevated flight altitudes lead to power losses in fuel cell powered aircrafts. As countermeasure ambient air can be pressurized with a suitable fuel cell air supply system. In this study the influence of low ambient pressures and pressure losses within the system on the performance of two turbo compressors and the resulting stack power are examined theoretically and the findings validated experimentally. Results show that decreasing ambient pressures and pressure losses in front and after the compressor reduce the maximum pressure from 2.4 to 1.6 bar(a) in the examined system. Air compression may require a significant share of the fuel cell stack power and the maximum system power is reduced from 54 to 41 kW. For air pressures higher than 1.8 bar(a) the fuel cell stack power gain due to pressurization is found to be cancelled out by the increasing power required for air compression.  相似文献   
55.
Thermal desorption spectroscopy (TDS) under ultra high vacuum (UHV) condition has been used to investigate the desorption characteristics of Cu/CeO2/γ-Al2O3 thin film catalysts coated onto the microchannel of a microreactor. TDS results demonstrate that surface desorption profiles and chemical properties (acid–base and redox properties) are remarkably influenced by the catalyst composition, i.e. the loading of copper and ceria. The enhanced basicity with the increase of ceria loading and the decrease of copper loading is evident from the shifted desorption maximum of CO2 in TDS spectra. Three oxygen species, ranging from weakly bound oxygen desorbed at low temperature to the strongly held lattice oxygen desorbed at high temperature, are easily discernible and clearly identified by O2 TDS spectra, depending on the catalyst compositions. The concomitant thermal desorption of O2, CO2, and H2O at low temperature indicates the unique chemical properties of copper/ceria catalyst with appropriate copper and ceria contents. The observed low-temperature feature is ascribed to the role of porthole of copper/ceria interfacial area for several desorbed species. The weakly bound oxygen species is attributed to the enhanced abundance of copper/ceria interfacial anionic vacancies created by the intimate contact between copper and ceria entities and its impact on steam reforming of methanol (SRM) reaction is tentatively discussed in terms of reverse oxygen spillover.  相似文献   
56.
Washing laundry is one of the most widespread housework in the world. Today, washing machines do this work in many private households, using water, electricity, chemical substances, and process time. Although energy efficiency is in the focus of many regulations which have already achieved significant improvements, the question remains, how relevant these processes are in terms of the absolute impact on resources and whether there are possibilities to improve even further by looking abroad. This survey, which is based on published data, compares the energy and water consumption for automatic laundry washing in an average private household with the total energy and water consumption of private households. Only little data are available on resource consumption for laundry washing and reliable figures based on in-use measurements are hard to obtain. But although some of the data in this report are poor, this is the first work that tries to elucidate the contribution of automatic laundry washing to the total electricity and water consumption of households in selected countries worldwide. The report estimates the resource consumption of roughly 590,000,000 washing machines in 38 countries with about 2.3 billion people, which is about one third of the world population. The results of this work show that laundry washing in private households is done with quite different amounts of electricity and water in different parts of the world both in absolute and relative comparison to the overall household consumption. But due to different consumer habits in dealing with the achieved washing performance in the different global regions, the best practice in washing laundry in a most sustainable way cannot be determined yet. Further research is needed to form a basis for a most sustainable development of resource consumption in private households.  相似文献   
57.
In some animals, such as mice and guinea pigs, a hormonally controlled mechanism increases the flexibility of the pubic symphysis and enhances the cervical remodeling necessary for safe delivery. Cervical ripening during pregnancy is associated with a paradoxical influx of leukocytes. However, the changes in cell metabolism during relaxation of the mouse pubic symphysis for delivery have not been extensively studied. In this work, we used light microscopy and transmission and scanning electron microcopy, as well as immunohistochemistry and Western blotting for MMP-8, to investigate the involvement of granulocytes or resident stromal cells in the relaxation of the virgin pubic symphysis during late pregnancy (days 18 and 19, before delivery) in vivo and in explanted joints. MMP-8 was studied because this collagenase is a hallmark for cervical ripening associated with the influx of granulocytes during late pregnancy. Extensive dissolution and disorganization of the extracellular matrix was seen around fibroblastic-like cells in late pregnancy. In contrast to the cervix (positive control), morphological and immunohistochemical analyses revealed that there was no characteristic cellular inflammatory response in the interpubic tissue. Staining for MMP-8 was observed in chondroid and fibroblastic-like cells of virgin and relaxed interpubic ligament, respectively. However, no granulocytes were seen during the extensive remodeling of the pubic joint in late pregnancy. These results indicate that constitutive stromal cells may have an important role in tissue relaxation during remodeling of the pubic symphysis in pregnancy.  相似文献   
58.
Reducing micropollutant pollution of water bodies is an important objective of water management and an integral part of environmental policy. Ceramic nanofiltration membranes were developed as multichannel membranes of increased membrane area and rotating disk filters. The membranes developed show retention of over 80 % for PEG 400. The membranes are currently being tested for the separation of micropollutants from wastewater contaminated with pharmaceuticals. With the help of a downstream oxidative process, the trace substances remaining in the permeate are degraded.  相似文献   
59.
Electronic Markets - Physical inactivity is a global public health problem that poses health risks to individuals and imposes financial burdens on already strained healthcare systems. Wearables...  相似文献   
60.
The sugar industry is concerned with color formation due to the oxidation of phenolic compounds in the presence of carbohydrates. In this study, we investigated the ozonation of a mixture of five phenolic compounds in water and aqueous sucrose solution: p-coumaric (p-COU), caffeic (CAF), syringic (SYR), and chlorogenic (CHO) acids, as well as the flavonoid quercetin (QUE). The experiments were carried out in a 3-L glass reactor with magnetic stirring and a diffuser plate at the bottom to feed the ozone-oxygen gas mixture. Initial solution concentrations of 5 mg L?1 of each acid, 15 mg L?1 of quercetin, and 40 g L?1 of sucrose were used. The degradation of phenolic compounds followed apparent first-order kinetics, with rate constants and percent removals decreasing in the presence of sucrose. In water, average consumed ozone dosages of 10.4 and 18.7 mg L?1 were necessary for 50% and 90% removals, respectively, for CHO, CAF, and p-COU; for QUE they were slightly higher (13.9 and 20.5 mg L?1, respectively). At a consumed dosage of 20.8 mg O3 L?1, more than 99% removal was obtained for CHO, CAF, and p-COU, while 96.2% was achieved for SYR. In contrast, QUE revealed to be more recalcitrant during ozonation in the absence of sucrose, with only 70% removal at the highest consumed O3 dosage. The consumed ozone dosages for 50% and 90% removals were higher for CHO, CAF, and p-COU in aqueous sucrose solution, which may impact ozone consumption during real sugarcane juice treatment. Sucrose and t-butanol were the main influential parameters that significantly affected the total amount of phenolic compounds degraded.  相似文献   
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