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231.
Y. Dubuc P. Janneteau R. Labont C. Roy F. Brire 《Journal of the American Water Resources Association》1986,22(2):297-303
ABSTRACT: The use of peatlands as the main form of wastewater treatment in a northern climate was studied for the James Bay Energy Society. The Fontanges campsite (70° 17′ 30″ W; 54° 34′ 00″ N) was chosen as the study site. In less than 1.5 km from the point of discharge BOD5, COD, total hardness, inorganic carbon, orthophosphates, total phosphorus, ammonia and total nitrogen were reduced by at least 90 percent. The peatland treatment system studied is divided into four components, each having a specific function. The first part combines the action of microorganisms and adsorption on peat, thus reducing the organic content while increasing the inorganic constituents. The second part uses peat to adsorb the inorganic elements already present in the wastewater and those produced in the first part of the system. The third component acts as an aerator, increasing the dissolved oxygen and decreasing the BOD5 levels of the water. The fourth part removes most of the remaining nutrients, thus acting like a tertiary treatment. Overall, peatlands seemed to be effective in treating domestic settled wastewater in a cold climate. 相似文献
232.
Long-chain fatty acid carbohydrate esters (FACE) were synthesized by the acid chloride-pyridine reaction to different degrees of substitution (DS). The hydrolyzed soybean oil was used as the source of unsaturated fatty acids. High molecular weight FACE polymers are insoluble in common solvents, such as benzene, toluene, THF, etc., and are highly water resistant. However, FACE polymers of hydrolyzed cellulose (MW 180 kD) are soluble/swellable in toluene and can be cast into tough, flexible films. FACE polymer properties of tensile strength and clasticity vary with degree of substitution and polymer size.Paper presented at the Bio/Environmentally Degradable Polymer Society—Third National Meeting, June 6–8, 1994, Boston, Massachusetts. 相似文献
233.
Y.A.W. de Kort A.L. Meijnders A.A.G. Sponselee W.A. IJsselsteijn 《Journal of environmental psychology》2006,26(4):309-320
Restorative environments are environments that can help restore depleted attention resources or reduce emotional and psychophysiological stress. These effects have been demonstrated not only in real environments, but also in mediated (projected, broadcasted, etc.) environments. However, the importance of simulation qualities to restoration outcomes has not been systematically studied. The present experiment investigates the importance of immersion in a mediated environment in relation to restoration. Is a projected natural environment more restorative when one is more immersed in it, and hence feels more present in it? The hypothesis was that a more immersive projection would show stronger stress-reducing effects of a mediated restorative environment. After performing a stress-inducing task, participants watched a nature film on either a high or low immersive screen. Physiological measurements (heart period and skin conductance level) were taken throughout the experiment. In addition, we measured self-reported affect and presence using the ITC-Sense of Presence Questionnaire. Significant effects of the screen size manipulation appeared on physiological measures, but not on self-reported affect. The data showed an interaction between screen size and restorative phase on heart period and skin conductance level, indicating stronger restoration for the immersive screen condition over time. We therefore conclude that immersion enhances restorative potential of a mediated natural environment. Self-reported affect did correlate significantly with experienced presence, illustrating the relevance of this experiential counterpart of immersion, although a mediating effect of presence has not yet been established. 相似文献
234.
Knut Veisten Ståle Navrud Johnny S. Y. Valen 《Journal of Environmental Planning and Management》2006,49(2):167-180
Previous contingent valuation (CV) studies on biodiversity have indicated that as much as one-quarter of the respondents show lexicographic preferences when facing biodiversity-money trade-offs. This behaviour is incompatible with welfare theory underlying CV, and thus questions the validity and reliability of the outcome of CV of changes in biodiversity. However, it is difficult from CV responses to distinguish between strict and modified lexicographic preferences, and those attaching a high value to biodiversity. This paper adds to the empirical evidence showing that what at first hand seems to represent strict lexicographic preferences is at most representing modified lexicographic preferences, and probably rather represent just high valuation of biodiversity. Data on both hypothetical and actual willingness to pay (WTP) from a CV study on biodiversity were used to perform tests of inconsistent attitudes to estimate the maximum share of non-compensatory preferences for biodiversity. The results show that there are very few respondents in the group that consistently state high preference for biodiversity preservation and show clear reluctance to trade-off biodiversity with other goods. However, this group also had higher WTP, both hypothetical and actual, than the reference group. This is consistent with exchange preferences and steep indifference curves. Thus, people with lexicographic preferences for biodiversity are probably less numerous than previously indicated. 相似文献
235.
Ming‐Hsi Hsu Chi‐Ray Wu Wen‐Cheng Liu Albert Y. Kuo 《Journal of the American Water Resources Association》2006,42(4):901-914
ABSTRACT: To comprehend the distributions of salinity, temperature, and suspended sediment in the Danshuei River estuary in Taiwan, monthly field surveys were conducted in 2003. These included several high and low slackwater surveys and intensive surveys. The results show that the Danshuei River estuary is predominately a partially mixed estuary. The highest concentration of suspended sediment is typically observed at the Chung‐Hsin Bridge, the most upstream sampling station. The suspended sediment concentration exhibits a general decreasing trend in the downstream direction. It may be concluded that the sediments mostly come from the upstream reach. A locally high concentration of suspended sediment is found at the Kuan‐Du station because of the local deep channel bathymetry and two‐layered estuarine circulation. A vertical two‐dimensional hydrodynamic and sediment transport model is applied to investigate the tidally averaged salinity distribution, residual circulation, and suspended sediment concentration. The modeling results reveal that, under the Q75 flow condition (i.e., low flow), a turbidity maximum occurs at the Kuan‐Du station due to the strong estuarine circulation. The model simulation with a much higher river flow condition results in a weaker residual circulation and weaker turbidity maximum. 相似文献
236.
Y Tachikawa M. Shiiba T Takasao 《Journal of the American Water Resources Association》1994,30(1):9-17
ABSTRACT: To make a distributed rainfall-runoff model, it is very important to build a model of topographic surface of a basin which takes account of the direction of water flow. In this paper, a geographic information system in hydrologic modeling, the BGIS (Basin Geomorphic Information Systems) are presented for modeling a river basin using a TIN-DEM (Triangulated Irregular Network - Digital Elevation Model) data structure. The BGIS have two core systems, which are the TIN-DEM generating system and the topographic analysis system. In the TIN-DEM generating system, landscapes are modeled as a set of contiguous non-overlapping terangular facets whose vertices are made up of points on a regular grid DEM and on river segments. These triangular facets are subdivided, if needed, so that each of them has only one side through which water flows out. The TIN-DEM generating system is made up of four modules, (1) a module for generating triangles from a grid DEM, (2) a module for getting rid of pits, (3) a module for joining discontinuous valley segments to a channel network, (4) a module for subdividing triangular facets. In the topographic analysis system, using datasets processed with the TIN-DEM generating system, a watershed source area for any segments in a stream network are delineated automatically, and topographic attributes of slopes, aspects, flow path lengths and upslope contributing areas are computed. 相似文献
237.
Behavior of dialifor, dimethoate, and methidathion in artificially fortified grape juice processed into wine. 总被引:1,自引:0,他引:1
N S Kawar Y Iwata M E Düsch F A Gunther 《Journal of environmental science and health. Part. B》1979,14(5):505-513
Dialifor and methidathion were added to diluted "Zinfandel" grape concentrate at 25 ppm and dimethoate at 1.0 and 25 ppm prior to fermentation with Saccharomyces cerevisiae. The finished wine 56 days later contained 10% (2.5 ppm) of the dialifor, 46% (12 ppm) of the methidathion and 85% (21 and 0.98 ppm) of the dimethoate added to the grape must. Residues in wine stored at 24 degrees C dissipated by hydrolysis; half-lives in wine were 7 days for dialifor and methidathion and 30 days for dimethoate. Residues were unchanged in wine in frozen storage for one year. Analysis of seven commercial wines for dimethoate indicated less than 0.03 ppm dimethoate was present; identity could not be confirmed by thin-layer chromatography at this level. 相似文献
238.
Natural food items of five species of marine cladocerans, Evadne nordmanni, E. tergestina, Penilia avirostris, Podon leuckarti and P. polyphemoides, were investigated in the Inland Sea of Japan between April 1986 and May 1987. Gut content examination with SEM (scanning electron microscopy) revealed that feeding was largely limited to centric diatoms and a few exceptions of pennate diatoms and dinoflagellates. No animal remains were detected, and some unidentified materials were also found. Phytoplankton smaller than 35 m in size (cell diameter in centric diatoms and longest dimension in others) was found most frequently in the gut of cladocerans. The role of grazing of marine cladocerans in trophodynamic pathways of the pelagic realm is discussed. 相似文献
239.
Investigation into the pressure resistance of 8 intertidal species belonging to the genera, Uca, Sesurma, Talorchestia and Littorina from the Northern Gulf of Mexico and Panama sheds light on the relationships between temperature and hydrostatic-pressure resistance. Generally, increasing temperature increases the pressure required to elicit reversible reactions such as increased activity and tetany, or paralysis, wheroas increasing temperature generally evokes the irreversible response of death (LD50) at a decreasing pressure. Tropical stenotherms tend to be more sensitive to hydrostatic pressure than eurythermal-temperate species at the same or similar temperatures. 相似文献