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171.
172.
Analytic webs support the synthesis of ecological data sets 总被引:1,自引:0,他引:1
173.
McFarland MJ Palmer GR Rasmussen SL Kordich MM Pollet DA Jensen JA Lindsay MH 《Journal of the Air & Waste Management Association (1995)》2006,56(7):1041-1051
The U.S. Department of Defense-approved activities conducted at the Utah Test and Training Range (UTTR) include both operational readiness test firing of intercontinental ballistic missile (ICBM) motors, as well as the destruction of obsolete or otherwise unusable ICBM motors through open burn/open detonation (OB/OD). Within the Utah Division of Air Quality, these activities have been identified as having the potential to generate unacceptable noise levels, as well as significant amounts of volatile organic compounds (VOCs). Hill Air Force Base, UT, has completed a series of field tests at the UTTR in which sound-monitoring surveillance of OB/OD activities was conducted to validate the Sound Intensity Prediction System (SIPS) model. Using results generated by the SIPS model to support the decision to detonate, the UTTR successfully disposed of missile motors having an aggregate net explosive weight (NEW) of 81,374 lb without generating adverse noise levels within populated areas. In conjunction with collecting noise-monitoring data, air emissions were collected to support the development of air emission factors for both static missile motor firings and OB/OD activities. Through the installation of 15 ground-based air samplers, the generation of combustion-fixed gases, VOCs, and chlorides was monitored during the 81,374-lb NEW detonation event. Comparison of field measurements to predictions generated from the US Navy energetic combustion pollutant formation model, POLU4WN, indicated that, as the detonation fire ball expanded, organic compounds, as well as CO, continued to oxidize as the combustion gases mixed with ambient air. VOC analysis of air samplers confirmed the presence of chloromethane, vinyl chloride, benzene, toluene, and 2-methyl-1-propene. Qualitative chloride analysis indicated that gaseous HCl was generated at low concentrations, if at all. 相似文献
174.
Gudbjerg J Trötschler O Färber A Sonnenborg TO Jensen KH 《Journal of contaminant hydrology》2004,75(3-4):297-318
Numerical simulation of steam injection into a water-saturated porous medium may be hindered by unphysical behavior causing the model to slow down. We show how spurious water flow may arise on the boundary between a steam zone and a saturated zone, giving rise to dramatic pressure drops. This is caused by the discretization of the temperature gradient coupled with the direct relation between pressure and temperature in the steam zone. The problem may be a severe limitation to numerical modeling. A solution is presented where the spurious water flow is blocked and this widely enhances the performance of the model. This new method is applied to a previously reported example exhibiting numerical problems. Furthermore, it is applied to the simulation of 2-D sandbox experiments where LNAPL is remediated from a smearing zone by steam injection. These experiments would have been difficult to analyze numerically without the adjustment to prevent spurious flow. 相似文献
175.
Karsten Klint Jensen 《Journal of Agricultural and Environmental Ethics》2006,19(3):269-283
When it comes to conflict over risk management priorities in food production, a number of observers, including myself, have
called for some sort of public deliberation as a means of resolving the moral disagreements underlying such conflicts. This
paper asks how, precisely, such deliberation might be facilitated. It is shown that representative democracy and the liberal
regulation that most Western democracies adhere to place important constraints on public deliberation. The challenge is to
find forums for public deliberation that can operate within these constraints while still making a constructive contribution. 相似文献
176.
Karsten Klint Jensen 《Journal of Agricultural and Environmental Ethics》2007,20(6):515-532
Is it legitimate for a business to concentrate on profits under respect for the law and ethical custom? On the one hand, there seems to be good reasons for claiming that a corporation has a duty to act for the benefit of all its stakeholders. On the other hand, this seems to dissolve the notion of a private business; but then again, a private business would appear to be exempted from ethical responsibility. This is what Kenneth Goodpaster has called the stakeholder paradox: either we have ethics without business or we have business without ethics. Through a different route, I reach the same solution to this paradox as Goodpaster, namely that a corporation is the instrument of the shareholders only, but that shareholders still have an obligation to act ethically responsibly. To this, I add discussion of Friedman’s claim that this responsibility consists in increasing profits. I show that most of his arguments fail. Only pragmatic considerations allow to a certain extent that some of the ethical responsibility is left over to democratic regulation. 相似文献
177.
Removal of NAPLs from the unsaturated zone using steam: prevention of downward migration by injecting mixtures of steam and air 总被引:1,自引:0,他引:1
Steam injection for remediation of porous media contaminated by nonaqueous phase liquids has been shown to be a potentially efficient technology. There is, however, concern that the technique may lead to downward migration of separate phase contaminant. In this work, a modification of the steam injection technology is presented, where a mixture of steam and air was injected. In two-dimensional experiments with unsaturated porous medium contaminated with nonaqueous phase liquids, it was demonstrated how injection of pure steam lead to severe downward migration. Similar experiments, where steam and air were injected simultaneously, resulted in practically no downward migration and still rapid cleanup was achieved. The processes responsible for the prevention of downward migration when injecting steam-air mixtures were analyzed using a nonisothermal multiphase flow and transport model. Hereby, three mechanisms were identified and it was demonstrated how the effectiveness of these mechanisms depended on the air-to-steam mixing ratio. 相似文献
178.
Environmental dynamics have important spatial dimensions, which calls for a spatial approach in policy analyses. Further to this, assessing agri-environmental policies involves analyses of individual measures as well as their combined effects on farmer behaviour and the environment. The integration of an economic behavioural model in a spatial framework has enabled analyses of a geographically targeted subsidy scheme for drinking water protection in combination with a uniform tax on commercial nitrogen fertilizer. Results show that policy measures for reducing nitrogen use can have combined effects (cross-achievements), thereby affecting each other's cost-effectiveness. Cross-achievements between a nitrogen fertilizer tax and a subsidy scheme based on elicitation are shown not to be additive, making partial analyses of policy measures more uncertain. 相似文献
179.
A.L. Jensen 《Ecological modelling》1982,15(2):127-144
The surplus production model, a conventional fishery stock assessment model, is applied to assess the entrainment and impingement impact of the Monroe Power Plant on the yellow perch standing stock and fishery in the western basni of Lake Erie. Biological parameters of the model are estimated from commercial catch and effort data and entrainment and impingement coefficients are estimated from power plant data. The model is applied to estimate stock biomass, egg production, and larva production; the proportions entrained and impinged are then estimated. The impact of water withdrawal on the equilibrium standing stock and maximum sustainable yield from the fishery is estimated and the impact of increased water withdrawal on the equilibrium standing maximum sustainable yield are larger than the proportion of the standing stock entrained and impinged, but the impact of the Monroe Power Plant is relatively small; it decreases biomass and the maximum sustainable yield of the yellow perch stock by only a few percent. However, there are several power plants impacting the yellow perch stock of the western basin of Lake Erie and the combined impact should be examined. 相似文献
180.
Skeletonema costatum (Grev.) Cleve grown in batch culture at low light intensity under a 14 h light: 10 h dark photocycle showed exponential cell proliferation (1.1 doublings d-1) without significant phasing of the cell division by the light: dark cycle. The growth in carbon concentration was, however, restricted to the light period. The turbidity of the culture closely followed the carbon oattern, and was not affected by the increase in the cell number during the dark period. It was found that a trustule suspension had only approximately 1% of the turbidity of the corresponding intact algae. Culture turbidity was therefore regarded as a biomass parameter similar to the carbon concentration, without direct correlation to the timing of the cell division. The short-time variations in the turbidity of growing algal cultures were further studied in a cage culture turbidostat. The growth rate (based on turbidity) increased rapidly during the first half of the light period, decreased slightly towards the evening and was zero throughout the dark period. When transformed to continuous light, the growth of the culture continued to show damped oscillations for up to 1 wk, but with a period of 26.7 h instead of 24 h. The same circadian rhythm was observed in chlorophyll content, and is thus possibly a reflection of a freely oscillating internal biological clock. The cage culture turbidostat was found to be a suitable device for studies of the photocycle related regulation of biosynthesis in S. costatum. 相似文献