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821.
This paper describes the development and testing of a deterministic simulation model for pest and resistance management of the Colorado potato beetle (CPB). Historically, CPB have developed resistance to new pesticides quickly. A potato farmer's pesticide application decisions trade off current crop yields and resistance development. The simulation incorporates major aspects of beetle life processes, pesticide resistance, and potato growth in order to predict the consequences of a pesticide application strategy over a ten-year planning horizon. 相似文献
822.
Duane H. Pontius Wallace B. Smith 《Journal of the Air & Waste Management Association (1995)》2013,63(12):1301-1303
ABSTRACTOzone reactivity scales play an important role in selecting which chemical compounds are used in products ranging from gasoline to pesticides to hairspray in California, across the United States and around the world. The California Statewide Air Pollution Research Center (SAPRC) box model that calculates ozone reactivity uses a representative urban atmosphere to predict how much additional ozone forms for each kilogram of compound emission. This representative urban atmosphere has remained constant since 1988, even though more than 25 years of emissions controls have greatly reduced ambient ozone concentrations across the United States during this time period. Here we explore the effects of updating the representative urban atmosphere used for ozone reactivity calculations from 1988 to 2010 conditions by updating the meteorology, emission rates, concentration of initial conditions, concentration of background species, and composition of volatile organic compound (VOC) profiles. Box model scenarios are explored for 39 cities across the United States to calculate the Maximum Incremental Reactivity (MIR) scale for 1,233 individual compounds and compound-mixtures. Median MIR values across the cities decreased by approximately 20.3% when model conditions were updated. The decrease is primarily due to changes in atmospheric composition ultimately attributable to emissions control programs between 1998 and 2010. Further effects were caused by changes in meteorological variables stemming from shifting seasons for peak ozone events (summer versus early fall). Lumped model species with the highest MIR values in 1988 experienced the greatest decrease in MIR values when conditions were updated to 2010. Despite the reduction in the absolute reactivity in the updated 2010 atmosphere, the relative ranking of the VOCs according to their reactivity did not change strongly compared to the original 1988 atmosphere. These findings indicate that past decisions about ozone control programs remain valid today, and the ozone reactivity scale continues to provide relevant guidance for future policy decisions even as new products are developed.Implications: Updating the representative urban atmosphere used for the Maximum Incremental Reactivity (MIR) scale from 1988 to 2010 conditions caused the reactivity of 1223 individual compounds and combined mixtures to decrease by an average of 20.3% but the relative ranking of the VOCs was not strongly affected. This means that previous guidance about preferred chemical formulations to reduce ozone formation in cities across the United States remain valid today, and the MIR scale continues to provide relevant guidance for future policy decisions even as new products are developed. 相似文献
823.
Robert G. Smith Alan Sherman 《Journal of the Air & Waste Management Association (1995)》2013,63(8):792-793
In colleges and universities across the country, courses in ecology and environmental science are among the newest additions to the catalog. The goal of such courses is to make students aware of the environmental dilemma, a just and necessary goal. However, there is a need to do more than this. Jobs dealing with environmental protection are becoming more and more complex due to the recent passage of State and Federal legislation, which includes the Clean Air Act, the Amendments to the Water Pollution Control Act and the Occupational Safety and Health Act, just to name a few. Trained personnel are needed by industry and government. For this reason, in 1971, Middlesex County College initiated an Environmental Health Science Technology Program. 相似文献
824.
P. Vann Bush Todd R. Snyder Wallace B. Smith 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1292-1297
Some of the features of the fluidized-bed combustion (FBC) process have a direct bearing on the particulate properties that most strongly influence filtering pressure drop. A laboratory program was conducted to experimentally determine the relative pressure drop characteristics of ashes from the TVA-EPRI 20-MW bubbling bed, atmospheric pressure FBC (AFBC) pilot plant and six pulverized-coal combustion (PC) units. The combined influences of measured particle and dust cake properties on filtering pressure drop were estimated with existing filtration theories. These theories predict a higher pressure drop for a dust cake produced with the AFBC ash than for one consisting of any of the PC ashes. Laboratory measurements were made of the flow resistance of idealized, simulated dust cakes to confirm these predictions. Field operating data from the fabric filters collecting some of the tested ashes were available to validate the laboratory results. The laboratory and field data show relatively good agreement. The AFBC ash must be treated as a special case for fabric filters, and careful selection of cleaning method and fabric must be made to minimize the inherently high pressure drop characteristics of this ash. 相似文献
825.
Jonathan R. Smith 《Journal of the Air & Waste Management Association (1995)》2013,63(9):969-970
A common part of many gas analyses using bubblers is to combine the contents of the first n-1 impingers and analyze them separate from the nth. The nth impinger, yielding as it should a nil result, confirms that all of the sample entering the train was caught and that the concentration calculated therefrom represents the “true” value. Many a hapless analyst has found himself stuck with nonzero nth impingers on occasion. Bemgloath tb reject the whole test, the analyst will often report the concentration based on the total catch (with appropriate qualifiers, of course). Another common practice is to calculate the percentage of the total catch in the first n-1 impingers. Sometimes this is reported, erroneously, as the sampler efficiency. The true sampler efficiency cannot be known (if it is less than 100%) because the presence of sample in the last impinger indicates that some unknown amount has passed through the train entirely. 相似文献
826.
Robert C. Carr Wallace B. Smith 《Journal of the Air & Waste Management Association (1995)》2013,63(6):694-699
This is the sixth and last part in a series of papers discussing the experience of electric utilities in applying baghouse technology for the collection of particulate matter at coal-fired electric power generating plants. The series presents new data obtained in research sponsored by the Electric Power Research Institute (EPRI) on reverse-gas and shake/deflate cleaned baghouses, and specifically addresses a number of unresolved issues in the design and operation of these units. This paper discusses research, development and demonstration activities now underway or planned to further understand baghouse technology to ensure efficient, economic and reliable service in utility applications. In addition, it summarizes the major findings reported in Parts I through V. 相似文献
827.
Gordon L. Smith 《Journal of the Air & Waste Management Association (1995)》2013,63(12):1154-1156
The basic engineering and economic factors relative to fabric filtration systems are reviewed. Fabrication and erection costs, and maintenance costs are then discussed in greater depth. 相似文献
828.
C. L. Burton D. A. Smith 《Journal of the Air & Waste Management Association (1995)》2013,63(2):139-143
An electrostatic precipitator, furnished on a 500-Mw tan-gentially-fired steam generator burning coal, was to collect 99.6% of the fly ash being generated in the furnace of this unit. Preliminary measurements indicated that the installation was not meeting its collection guarantee. Precipitator outlet flue dust distribution indicated that poor gas flow distribution might be one of the causes of the low performance. When observation ports were installed in the outlet flue to permit a direct visual evaluation of the problem, it was found that high velocity jets were present in the collecting electrodes, and that hopper sweepage was present. A model study along with velocity distribution measurements of the installation were authorized. Flow analysis indicated that the field and model correlated well. Extensive changes were made in the model, which eliminated or minimized the high velocity jets and hopper sweepage. After these changes were made in the field installation, it was able to achieve the required dust collection efficiency. 相似文献
829.
Integrated Environmental Assessment of the Mid-Atlantic Region with Analytical Network Process 总被引:1,自引:0,他引:1
A decision analysis method for integrating environmental indicators was developed. This was a combination of Principal Component Analysis (PCA) and the Analytic Network Process (ANP). Being able to take into account the interdependency among variables, the method was capable of ranking ecosystems in terms of environmental conditions and suggesting cumulative impacts across a large region. Using data on land cover, population, roads, streams, air pollution, and topography of the Mid-Atlantic Region of the United States, we were able to point out areas which were in relatively poor condition and/or vulnerable to future deterioration regarding various environmental aspects. The method offered an easy and comprehensive way to combine the strengths of conventional multivariate statistics (PCA) and decision-making science tool (ANP) for integrated environmental assessment. 相似文献
830.
Locantore NW Tran LT O'Neill RV McKinnis PW Smith ER O'Connell M 《Environmental monitoring and assessment》2004,94(1-3):249-261
The U.S. Environmental Protections Agency's (U.S. EPA) Regional Vulnerability Assessment(ReVA) program has focused much of its research over the last five years on developing and evaluating integration methods for spatial data. An initial strategic priority was to use existing data from monitoring programs, model results, and other spatial data. Because most of these data were not collected with an intention of integrating into a regional assessment of conditions and vulnerabilities, issues exist that may preclude the use of some methods or require some sort of data preparation. Additionally, to support multi-criteria decision-making, methods need to be able to address a series of assessment questions that provide insights into where environmental risks are a priority. This paper provides an overview of twelve spatial integration methods that can be applied towards regional assessment, along with preliminary results as to how sensitive each method is to data issues that will likely be encountered with the use of existing data. 相似文献