共查询到20条相似文献,搜索用时 15 毫秒
1.
F.L. Ludwig R.C. Sandys A.E. Moon 《Journal of the Air & Waste Management Association (1995)》2013,63(6):499-504
Three separate mathematical models were combined to calculate the changes in carbon monoxide (CO) concentrations that might result from traffic engineering changes. The three models used were: (1) The Dynamic Highway Transportation model (DHTM) which relates traffic flow patterns to physical parameters and traffic signal characteristics of a network; (2) an emission model that predicts CO emissions from traffic flow parameters such as number of stops, idling time, etc; and (3) the APRAC-1A urban diffusion model which calculates CO concentrations from source distributions and meteorological factors. The composite model was applied to traffic in downtown Chicago for a specific set of meteorological conditions. Results are compared for two traffic signal control schemes. In those blocks where concentrations were highest, the model indicates a 20% reduction is possible through improved traffic signal controls. The model should be useful for testing other traffic control measures. 相似文献
2.
Managing the Three-Rivers Headwater Region, China: From Ecological Engineering to Social Engineering 总被引:1,自引:0,他引:1
Yiping Fang 《Ambio》2013,42(5):566-576
The three-rivers headwater region (THRHR) of Qinghai province, China plays a key role as source of fresh water and ecosystem services for central and eastern China. Global warming and human activities in the THRHR have threatened the ecosystem since the 1980s. Therefore, the Chinese government has included managing of the THRHR in the national strategy since 2003. The State Integrated Test and Demonstration Region of the THRHR highlights the connection with social engineering (focus on improving people’s livelihood and well-being) in managing nature reserves. Based on this program, this perspective attempts a holistic analysis of the strategic role of the THRHR, requirements for change, indices of change, and approaches to change. Long-term success of managing nature reserves requires effective combination of ecological conservation, economic development, and social progress. Thus, the philosophy of social engineering should be employed as a strategy to manage the THRHR. 相似文献
3.
Acidification of soils and surface waters caused by acid deposition is still a major problem in southern Scandinavia, despite
clear signs of recovery. Besides emission control, liming of lakes, streams, and wetlands is currently used to ameliorate
acidification in Sweden. An alternative strategy is forest soil liming to restore the acidified upland soils from which much
acidified runoff originates. This cost–benefit analysis compared these liming strategies with a special emphasis on the time
perspective for expected benefits. Benefits transfer was used to estimate use values for sport ffishing and nonuse values in terms of existence values. The results show that large-scale forest soil liming is not socioeconomically profitable, while
lake liming is, if it is done efficiently—in other words, if only acidified surface waters are treated. The beguiling logic
of “solving” an environmental problem at its source (soils), rather than continuing to treat the symptoms (surface waters),
is thus misleading. 相似文献
4.
Carolyn B. Doty Curtis C. Travis 《Journal of the Air & Waste Management Association (1995)》2013,63(12):1535-1543
Abstract Although the Superfund remedial action decision process is a complex process involving a variety of technical, political, and public health issues, the primary goal of remedial action is the protection of public health. We performed an in-depth analysis of 50 post-SARA Records of Decision in order to characterize the role of risk assessment in the decision-making process and determine whether decisions are being made in an effective and environmentally protective manner. Our findings indicate that the majority of decisions to remediate Superfund sites are based on the existence of contamination per se and not on actual public health risk. Although hypothetical risk is an essential consideration, this gray area is not well-defined in the current decision-making process. The lack of assessment of the degree of risk reduction associated with the remedial alternatives evaluated and the lack of support indicating the effectiveness of the remedial alternatives selected also constitute major weaknesses in the majority of decisions. These inadequacies undermine rationales regarding the protectiveness and cost-effectiveness of the remedial alternatives selected. The fact that objectives beyond addressing public health risk are often unclear in the decision-making process also weakens rationales for costeffectiveness. 相似文献
5.
Swanson J Kittelson D Pui D Watts W 《Journal of the Air & Waste Management Association (1995)》2010,60(10):1177-1191
This paper is part of the Journal of the Air & Waste Management Association's 2010 special issue on combustion aerosol measurements. The issue is a combination of papers that synthesize and evaluate ideas and perspectives that were presented by experts at a series of workshops sponsored by the Coordinating Research Council that aimed to evaluate the current and future status of diesel particulate matter (DPM) measurement. Measurement of DPM is a complex issue with many stakeholders, including air quality management and enforcement agencies, engine manufacturers, health experts, and climatologists. Adoption of the U.S. Environmental Protection Agency 2007 heavy-duty engine DPM standards posed a unique challenge to engine manufacturers. The new standards reduced DPM emissions to the point that improvements to the gravimetric method were required to increase the accuracy and the sensitivity of the measurement. Despite these improvements, the method still has shortcomings. The objectives of this paper are to review the physical and chemical properties of DPM that make gravimetric measurement difficult at very low concentrations and to review alternative metrics and methods that are potentially more accurate, sensitive, and specific. Particle volatility, size, surface area, and number metrics are considered, as well as methods to quantify them. Although the authors believe that an alternative method is required to meet the needs of engine manufacturers, the methods reviewed in the paper are applicable to other areas where the gravimetric method detection limit is approached and greater accuracy and sensitivity are required. The paper concludes by suggesting a method to measure active surface area, combined with a method to separate semi-volatile and solid fractions to further increase the specificity of the measurement, has potential for reducing the lower detection limit of DPM and enabling engine manufacturers to reduce DPM emissions in the future. 相似文献
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7.
Ronald J. Turner 《Journal of the Air & Waste Management Association (1995)》2013,63(6):728-737
The Hazardous and Solid Waste Amendments to the Resource Conservation and Recovery Act direct the Environmental Protection Agency to determine the available treatment technologies for a number of hazardous waste streams, including halogenated organics. If it is determined that existing technology and capacity is sufficient for the safe management of the designated halogenated organic wastes, these wastes will be prohibited from land disposal, effective July 8,1987. This article summarizes the general characteristics and treatment alternatives for this waste category. 相似文献
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9.
Climate Change Impact on Riverine Nutrient Load and Land-Based Remedial Measures of the Baltic Sea Action Plan 总被引:1,自引:0,他引:1
To reduce eutrophication of the Baltic Sea, all nine surrounding countries have agreed upon reduction targets in the HELCOM Baltic Sea Action Plan (BSAP). Yet, monitoring sites and model concepts for decision support are few. To provide one more tool for analysis of water and nutrient fluxes in the Baltic Sea basin, the HYPE model has been applied to the region (called Balt-HYPE). It was used here for experimenting with land-based remedial measures and future climate projections to quantify the impacts of these on water and nutrient loads to the sea. The results suggest that there is a possibility to reach the BSAP nutrient reduction targets by 2100, and that climate change may both aggravate and help in some aspects. Uncertainties in the model results are large, mainly due to the spread of the climate model projections, but also due to the hydrological model. 相似文献
10.
B.M. Gawlik N. Sotiriou E.A. Feicht S. Schulte-Hostede A. Kettrup 《Chemosphere》1997,34(12):2525-2551
The determination of the soil adsorption behaviour of an environmental chemical is very important to the evaluation of potential dangers for man and nature. One of the major problems for European regulators working in the field of environmental protection and risk assessment is the lack of complete and comparable soil sorption data, e.g. Koc values. The large number of existing chemicals makes it necessary to develop and apply fast methods as an alternative to classical batch or column studies. Based on this context numerous approaches to estimate Koc have been published during the past two decades.
In this paper more than 200 existing relationships for Koc estimations have been reviewed and divided into four categories. Regression equations for the most important classes of non-ionic organic environmental chemicals able to estimate soil adsorption coefficients are summarised, and the advantages and drawbacks of the different approaches are discussed briefly.
Due to the fact that a broad application of the proposed approaches is limited by the quality and comparability of the underlying experimental Koc values reference soils are postulated to create a common basis for the comparison of soil adsorption coefficients. 相似文献
11.
文中综述了氰化物的危害和含氰废水的来源以及目前处理含氰废水的方法。以工程实例重点介绍亚铁蓝法处理此废水的应用。亚铁蓝法除氰可分二级进行,第一级在中性条件总氰去除率达到80%以上,第二级直接在一级出水加碱调pH至8~9沉淀即可,通过二级处理总氰去除率达到95%左右。 相似文献
12.
George Arnold Sc.D. E. Edgerley Jr. 《Journal of the Air & Waste Management Association (1995)》2013,63(4):235-237
The air basin between the Mississippi River and the bluff in Illinois is of particular interest for this report. The autumnal temperature profiles were measured by a wiresonde. Each day through September and October had an inversion at dawn and/or dusk. During the entire three months, inversions 5° or more occurred at dawn 64% of the mornings, those 10° or more occurred 45% of the mornings; and those 15° occurred 23% of the mornings. Under intense inversions, the topography holds cool air in the basin like water in a saucer, and currents within this 200-ft air layer comprise a quasi-closed circulation system. A frequent pattern of air circulation involves a northwestward surface drift in the basin, with a southwest wind aloft and an updraft over St. Louis. This forms a horizontal semi-vortex along the river, concentrating the heavier particulates near East St. Louis and Granite City. Multiple evidence showed this pattern to exist one morning among four. Business interests would use the basin for industrial expansion, but air resource planners prefer to keep new air pollution sources out of this low land. 相似文献
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14.
Hajime Masukawa Masaharu Kitashima Kazuhito Inoue Hidehiro Sakurai Robert P. Hausinger 《Ambio》2012,41(2):169-173
To mitigate global warming caused by burning fossil fuels, a renewable energy source available in large quantity is urgently required. We are proposing large-scale photobiological H2 production by mariculture-raised cyanobacteria where the microbes capture part of the huge amount of solar energy received on earth’s surface and use water as the source of electrons to reduce protons. The H2 production system is based on photosynthetic and nitrogenase activities of cyanobacteria, using uptake hydrogenase mutants that can accumulate H2 for extended periods even in the presence of evolved O2. This review summarizes our efforts to improve the rate of photobiological H2 production through genetic engineering. The challenges yet to be overcome to further increase the conversion efficiency of solar energy to H2 also are discussed. 相似文献
15.
Craig F. Novak 《Journal of contaminant hydrology》1996,21(1-4)
The Fracture-Matrix Transport (FMT) code couples saturated porous medium advection and diffusion with mechanistic chemical models for speciation and interphase reactions. Previous versions of FMT simulated double-porosity transport in two dimensions on the continuum from advection- to diffusion-dominated, with a user-specified velocity field to allow double-porosity transport. However, aqueous density was assumed constant, and reactive minerals were assumed to occupy negligible volume. Both of these assumptions can be considered poor for evaporite systems, where large changes in porosity and aqueous density can result from high mineral solubilities. Further development of FMT has relaxed these restrictions, allowing aqueous density to vary with phase composition, and allowing void volume to change as minerals dissolve and precipitate. This paper describes the additional mathematical complexity and code modifications required to simulate such systems. The sensitivity of advection-dominated transport to these variables is explored briefly in a one-dimensional example. 相似文献
16.
The behaviour of Hediste diversicolor from the Humber was investigated under different concentrations of copper sulphate. A range of behaviours were indicative of metal-stress. These included consistent attempts at burrowing, eversion of the proboscis and abnormal crawling. The bioassay itself consisted of exposing worms to increasing concentrations of copper sulphate and recording the concentration at which a stress response was elicited. The behavioural end-points were shown to be a good predictor of time of death of Fal estuary worms under acutely toxic conditions. The bioassay would therefore allow the separation of tolerance phenotypes without mortality to the worm. Worms were not affected by consecutive bioassays and it was proposed that tolerance to more than one metal could be determined for individual worms. 相似文献
17.
介绍了砀山县近期处理规模为25000m^3/d、采用一体化氧化沟工艺的污水处理厂的设计情况,并针对雨污合流制采取了一系列的解决措施。 相似文献
18.
Soliman AS Jacko RB Palmer GM 《Journal of the Air & Waste Management Association (1995)》2006,56(11):1540-1549
The purpose of the study was to quantify the impact of traffic conditions, such as free flow and congestion, on local air quality. The Borman Expressway (I-80/94) in Northwest Indiana is considered a test bed for this research because of the high volume of class 9 truck traffic traveling on it, as well as the existing and continuing installation of the Intelligent Transportation System (ITS) to improve traffic management along the highway stretch. An empirical traffic air quality (TAQ) model was developed to estimate the fine particulate matter (PM2.5) emission factors (grams per kilometer) based solely on the measured traffic parameters, namely, average speed, average acceleration, and class 9 truck density. The TAQ model has shown better predictions that matched the measured emission factor values more than the U.S. Environmental Protection Agency (EPA)-PART5 model. During congestion (defined as flow-speeds < 50 km/hr [30 mi/hr]), the TAQ model, on average, overpredicted the measured values only by a factor of 1.2, in comparison to a fourfold underprediction using the EPA-PART5 model. On the other hand, during free flow (defined as flow-speeds > 80 km/hr [50 mi/hr]), the TAQ model was conservative in that it overpredicted the measured values by 1.5-fold. 相似文献
19.
Joy RW Heirigs PL Torgerson GD St Denis M Austin TC Gordon J Tefft B Lindner J 《Journal of the Air & Waste Management Association (1995)》2004,54(3):269-285
A series of studies was performed to develop an alternative to the U.S. Environmental Protection Agency's gold standard IM240 mass-based emission test. The new IM147 test was based on the second phase of the IM240 that consists of 147 sec of transient vehicle operation. Paired IM240/IM147 tests were conducted on vehicles ranging from 1981 to 1996 to determine IM147 cutpoints and excess emissions were identified. Additionally, an optimized test procedure was developed that combined possible triplicate IM147s with improved drive trace quality control, fast-pass, and retest methods. The optimized procedure was found to provide improved vehicle preconditioning with a relatively minor decrease in excess emissions identification. Resulting identification rates ranged from 96 to 100% for hydrocarbons (HC), 93-100% for CO, and 93-100% for NOx, depending on cutpoint selection, while false failures caused by lack of vehicle preconditioning were reduced to essentially zero. Significant vehicle throughput improvements were achieved through the development of software algorithms involving modal fast-pass and retest procedures. Modal drive trace variation limits also were developed to improve test accuracy. The combination of the algorithms reduced average IM147 test times by nearly 60%. 相似文献
20.
对AB工艺处理毛纺废水进行了系统研究,在预处理和生物吸附处理阶段作了一些技术改进,并结合江苏箭鹿集团第一毛纺厂处理毛纺废水的工程实例,对其工作原理、工艺流程、设计参数以及效益等作了详细的分析,实践证明:运用效果显著。 相似文献