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11.
Emissions from passenger ferries operating in urban harbors may contribute significantly to emissions inventories and commuter exposure to air pollution. In particular, ferries are problematic because of high emissions of oxides of nitrogen (NOx) and particulate matter (PM) from primarily unregulated diesel engines. This paper explores technical solutions to reduce pollution from passenger ferries operating in the New York-New Jersey Harbor. The paper discusses and demonstrates a mixed-integer, non-linear programming model used to identify optimal control strategies for meeting NOx and PM reduction targets for 45 privately owned commuter ferries in the harbor. Results from the model can be used by policy-makers to craft programs aimed at achieving least-cost reduction targets.  相似文献   
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This article is about Total Quality Management and its relationship to corporate environmental affairs. As the TQM movement expands, the commitment to continuous quality improvement, customer satisfaction, and collaborative, team-oriented workplaces is finding new applications. Just as the success of Federal Express, AT&T, and other winners of the Malcolm Baldrige National Quality Award shows that Total Quality Management can transform a business, we also are learning of successes companies are having applying TQM principles to environmental management. Our experience with TQM and environmental management at Coors Brewing Company is in the area of pollution prevention. In addition to our brewing operations, we also operate the country's largest aluminum can manufacturing plant, where we produce 4 billion cans a year, a separate facility that makes the can tops, a glass bottle manufacturing plant, and various support facilities. In all, we have some 7,000 employees, and building a commitment to pollution prevention in an operation of that size requires much more than just adopting quality principles. In this article we show how it also means understanding how those principles will mesh with the corporate culture. What we found is that before TQM can begin its magic, a company must review its own culture to see how problems have traditionally been solved and how challenges have been met.  相似文献   
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ABSTRACT: As part of a study of Redwood National Park in north-western California, an investigation was conducted from June to November 1974 on intragravel dissolved oxygen and sediment in three tributaries to Redwood Creek, a major coastal stream that flows through Redwood National Park. Of concern was whether the intragravel environment of streams in logged and unlogged redwood-forested drainage basins was different. The tributary in the unlogged drainage basin had lower percentages of fine streambed sediment than either of the tributaries in logged drainage basins. Concentration and percentage saturation of dissolved oxygen of intragravel water were highest in the stream in the unlogged drainage basin, intermediate in the stream in the patch-cut drainage basin, and lowest in the stream in the clear-cut drainage basin. The differences in intragravel dissolved-oxygen conditions among the three tributaries are attributed chiefly to differences in their interchange of surface and intragravel water. The larger quantities of fine streambed sediment in the two streams in logged basins may have reduced the permeability of the streambeds and hence their capacity to interchange surface and intragravel water. However, differences in the lithology of the three tributary drainage basins examined may contribute to the differences in the percentage of fine sediments observed among the streams, even in the absence of logging.  相似文献   
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Thoracic deformation under an applied load is an established indicator of injury risk, but the force required to achieve an injurious level of deformation currently is not understood adequately. This article evaluates how two potentially important factors, loading condition and muscle tensing, affect the structural response of the dynamically loaded thorax. Structural models of two human cadaver thoraxes and two porcine thoraxes were used to quantify the effects. The human cadavers, which represent anthropometric extremes, were subjected to anterior loading from (1) a 5.1-cm-wide belt oriented diagonally (i.e., seatbelt-like loading), (2) a 15.2-cm-diameter rigid hub, and (3) a 20.3-cm-wide belt oriented laterally (i.e., a distributed load). A structural model having the mathematical formulation of a quasilinear viscoelastic material model was used to model the elastic and viscous response, with ramp-hold tests used to determine the model coefficients. The effect of thoracic musculature was assessed using similar ramp-hold tests on the porcine subjects, each with and without forced muscle contraction. Even maximally contracted thoracic musculature is shown to have a minimal effect on the response, with similar elastic and viscous characteristics exhibited by each subject regardless of muscle tone. The elastic response is shown to be approximately a factor of three stiffer for diagonal belt loading and for this distributed loading condition than for the hub loading, indicating that the response is influenced most by the particular anatomical structures that are engaged and, secondarily, by the area of load application. Specifically, shoulder involvement is shown to have a strong influence. The force relaxation is found to be pronounced, but insensitive to the loading condition, with long-time force relaxation coefficients (G( infinity )) in the range of 0.1 to 0.3. The findings of this study provide restraint-specific guidelines for the force-deflection characteristics of both physical and computational thoracic models.  相似文献   
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This paper presents results from field studies carried out during the 1993-1998 Australian cotton (Gossypium hirsutum L.) seasons to monitor off-target droplet movement of endosulfan (6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepin 3-oxide) insecticide applied to a commercial cotton crop. Averaged over a wide range of conditions, off-target deposition 500 m downwind of the field boundary was approximately 2% of the field-applied rate with oil-based applications and 1% with water-based applications. Mean airborne drift values recorded 100 m downwind of a single flight line were a third as much with water-based application compared with oil-based application. Calculations using a Gaussian diffusion model and the U.S. Spray Drift Task Force AgDRIFT model produced downwind drift profiles that compared favorably with experimental data. Both models and data indicate that by adopting large droplet placement (LDP) application methods and incorporating crop buffer distances, spray drift can be effectively managed.  相似文献   
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The paper introduces the theory of graceful extensibility which expresses fundamental characteristics of the adaptive universe that constrain the search for sustained adaptability. The theory explains the contrast between successful and unsuccessful cases of sustained adaptability for systems that serve human purposes. Sustained adaptability refers to the ability to continue to adapt to changing environments, stakeholders, demands, contexts, and constraints (in effect, to adapt how the system in question adapts). The key new concept at the heart of the theory is graceful extensibility. Graceful extensibility is the opposite of brittleness, where brittleness is a sudden collapse or failure when events push the system up to and beyond its boundaries for handling changing disturbances and variations. As the opposite of brittleness, graceful extensibility is the ability of a system to extend its capacity to adapt when surprise events challenge its boundaries. The theory is presented in the form of a set of 10 proto-theorems derived from just two assumptions—in the adaptive universe, resources are always finite and change continues. The theory contains three subsets of fundamentals: managing the risk of saturation, networks of adaptive units, and outmaneuvering constraints. The theory attempts to provide a formal base and common language that characterizes how complex systems sustain and fail to sustain adaptability as demands change.  相似文献   
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We report the application of an infrared (IR) differential absorption Lidar (DIAL) system (also capable of ultra violet measurements) built at the National Physical Laboratory (NPL), UK, to field measurements of total site emissions (controlled and fugitive) from petrochemical and landfill installations. The validation of the IR-DIAL was carried out via a series of controlled field experiments including comparison to GC analysis and tests against controlled methane releases from a test stack, all detailing agreements on the order of ±20%. In volatile organic compound (VOC) measurements at a UK petrochemical site it was found that the American Petroleum Institute's methodology of the time for calculating the emitted flux underestimated by a factor of 2.4. Also, in a similar field trial it was found that scaling traditional point measurements at easily accessible flanges and valves to represent all flanges and valves on a site led to an underestimation by a factor of 6. In addition to petrochemical examples we also report field measurements from a landfill site to demonstrate the advantageous of the DIAL technique for monitoring area emission sources. In this case study it was found that active (still being filled) cells resulted in significantly greater VOC emission rates (30 kg h(-1)) than closed (≤ 10 kg h(-1)).  相似文献   
19.
Various governmental regulatory agencies are responsible for establishing regulations on the discharge of chlorinated organic compounds from pulp and paper mills. The procedures for setting permit limits are the basic topic of this article. Different methods of determining permit limits are set forth and discussed in a number of references, including documents of the Environmental Protection Agency. This paper discusses in detail the application of one particular methodology—the lognormal model approach. In this paper we utilize a real data set and include the necessary calculations required to set up permit limits. The basic tenets of the permit process are such that if limits are set too low, operators who are in full regulatory compliance will still be frequently cited, and if limits are set too high, operators who are not in compliance will seldom if ever be cited. Thus there is a great need for these effluent limits to be determined with great care, both to protect the environment receiving the wastewater and the industry producing the wastewater.  相似文献   
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