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271.
W. Graham Glen Michael P. Zelenka Richard C. Graham 《Atmospheric environment (Oxford, England : 1994)》1996,30(24):4225-4232
A model which quantifies the relationship between the monthly time series for CO emissions, the monthly time series in ambient CO concentration, and meteorologically driven dispersion was developed. Fifteen cities representing a wide range of geographical and climatic conditions were selected. An eight-year time series (1984–1991 inclusive) of monthly averaged data were examined in each city. A new method of handling missing ambient concentration values which is designed to calculate city-wide average concentrations that follow the trend seen at individual monitor sites is presented. This method is general and can be used in other applications involving missing data. The model uses emissions estimates along with two meteorological variables (wind speed and mixing height) to estimate monthly averages of ambient air pollution concentrations. The model is shown to have a wide range of applicability; it works equally well for a wide range of cities that have very different temporal CO distributions. The model is suited for assessing long-term trends in ambient air pollutants and can also be used for estimating seasonal variations in concentration, estimation of trends in emissions, and for filling in gaps in the ambient concentration record. 相似文献
272.
Debera A. Backhus Flynn W. Picardal Scott Johnson Tracy Knowles Richard Collins Anna Radue Sanggoo Kim 《Journal of contaminant hydrology》1997,28(4):337-361
Sorption of organic contaminants to soils has been shown to limit bioavailability and biodegradation in some systems. Use of surfactants has been proposed to reverse this effect. In this study, the effects of a high organic carbon content soil and a nonionic surfactant (Triton X-100) on the reductive dechlorination of carbon tetrachloride (CCl4) were examined in anaerobic systems containing Shewanella putrefaciens. Although more than 70% of the added CCl4 was sorbed to the soil phase in these systems, the reductive dechlorination of CCl4 was not diminished. Rather, rates of CCl4 dechlorination in systems containing soil were enhanced relative to systems containing non-sorptive sand slurries. This enhancement was also observed in sterile soil slurries to which a chemical reductant, dithiothreitol was added. It appears that the organic soil used in these experiments contains some catalytic factor capable of transforming CCl4 in the presence of an appropriate chemical or microbial reductant. The addition of Triton X-100 to sand and soil slurries containing S. putrefaciens resulted in increased CCl4 degradation in both systems. The effect of Triton could not be explained by: (i) surfactant induced changes in the distribution of CCl4, (i.e. decreased sorption) or the rate of CCl4 desorption; (ii) a direct reaction between Triton and CCl4; or (iii) increased cell numbers resulting from use of the surfactant as a substrate. Rather, it appears that Triton X-100 addition resulted in lysis of bacterial cells, a release of biochemical reductant, and enhanced reductive transformation of CCl4. These results provide insights to guide the development of more effective direct or indirect bioremediation strategies. 相似文献
273.
274.
The organic fraction of a municipal solid waste was added in different doses to an eroded soil formed of loam and with no
vegetal cover. After three years, the changes in macronutrient content and the chemical-structural composition of its organic
matter were studied. The addition of the organic fraction from a municipal solid waste had a positive effect on soil regeneration,
the treated soils being covered with spontaneous vegetation from 1 yr onwards. An increase in electrical conductivity and
a fall in pH were noted in the treated soils as were increases in macronutrients, particularly N and available P and the different
carbon fractions. Optical density measurements of the organic matter extracted with sodium pyrophosphate showed that the treated
soils contained an organic matter with less condensed compounds and with a greater tendency to evolve than the control. A
pyrolysis-gas chromatography study of the organic matter extracted with pyrophosphate showed large quantities of benzene both
in the treated soils and control; pyrrole was also relatively abundant, although this fragment decreased as the dose rose.
Xylenes and pyridine were present in greater quantities in the control and furfural in the treated soils. Three years after
addition to the soil, the organic matter had a higher proportion of fragments derived from aromatic compounds and a smaller
proportion derived from hydrocarbons. Similarity indices showed that, although the added and newly formed organic matter 3
yr after addition continued to differ from that of the original soil and to be more mineralizable, the transformations it
has undergone made it more similar to the original organic matter of the soil than it was at the moment of being added. 相似文献
275.
金磊 《中国安全科学学报》1992,(3)
结合对电气可靠性技术的宏观分析态势及安全减灾[9][10]的迫切要求,研究了实用的漏电开关质量可靠性评价指标及分析模型;针对漏电开关的故障,提出了构筑现代民用建筑(多指住宅)供用电安全网络的实施要点及有关标准化措施。 相似文献
276.
Paul Schroeder 《Environmental management》1991,15(4):475-481
A possible response to increasing atmospheric CO2 concentration is to attempt to increase the amount of carbon stored in terrestrial vegetation. One approach to increasing
the size of the terrestrial carbon sink is to increase the growth of forests by utilizing intensive forest management practices.
This article uses data from the literature and from forest growth and yield models to analyze the impact of three management
practices on carbon storage: thinning, fertilization, and control of competing vegetation. Using Douglas-fir (Pseudotsuga menziesii) and loblolly pine (Pinus taeda) as example species, results from experiments with computer simulation models suggest that, for these two species, thinning
generally does not increase carbon storage and may actually cause a decrease. The exception is thinning of very dense young
stands. Fertilization generally increases carbon storage, although the response can be quite variable. The largest gains in
carbon storage are likely to come from fertilizing lower-quality sites and from fertilizing thinned or less dense stands.
Forests usually show increased growth in response to fertilization over a wide range of ages. Simulation of the growth of
loblolly pine indicates that controlling competing vegetation at an early age helps to maximize stand growth and carbon storage.
The research described in this article has been funded by the US Environmental Protection Agency. This document has been prepared
at the EPA Environmental Research Laboratory in Corvallis, Oregon, through contract number 68-C8-0006 to NSI Technology Inc.
It has been subjected to the agency’s peer and administrative review and approved for publication. Mention of trade names
or commercial products does not constitute endorsement or recommendation for use. 相似文献
277.
Stanley A. Temple 《Environmental management》1996,20(6):873-878
The synthetic field of conservation biology uses principles derived from many different disciplines to address biodiversity issues. Many of these principles have come from ecology, and two simple ones that seem to relate to many issues involving the utility industry are: (1) Everything is interconnected (and should usually stay that way), and (2) We can never do merely one thing. The first principle can be applied to both the biotic and physical environments that are impacted by industrial activities. Habitat fragmentation and the loss of physical and biotic connectedness that results are frequently associated with transmission rights-of-way. These problems can be reduced—or even turned into conservation benefits—by careful planning and creative management. The second principle applies to the utility industry's programs to deal with carbon released by burning fossil fuels. Ecological knowledge can allow these programs to contribute to the preservation of biodiversity in addition to addressing a pollution problem. Without careful ecological analyses, industry could easily create new problems while implementing solutions to old ones. 相似文献
278.
Noel J. Cutright 《Environmental management》1996,20(6):913-918
One of the most pressing environmental issues today is the possibility that projected increases in global emissions of greenhouse gases from increased deforestation, development, and fossil-fuel combustion could significantly alter global climate patterns. Under the terms of the United Nations Framework Convention on Climate Change, signed in Rio de Janeiro during the June 1992 Earth Summit, the United States and other industrialized countries committed to balancing greenhouse gas emissions at 1990 levels in the year 2000. Included in the treaty is a provision titled Joint Implementation, whereby industrialized countries assist developing countries in jointly modifying long-term emission trends, either through emission reductions or by protecting and enhancing greenhouse gas sinks (carbon sequestration). The US Climate Action Plan, signed by President Clinton in 1993, calls for voluntary climate change mitigation measures by various sectors, and the action plan included a new program, the US Initiative on Joint Implementation. Wisconsin Electric decided to invest in a Jl project because its concept encourages creative, cost-effective solutions to environmental problems through partnering, international cooperation, and innovation. The project chosen, a forest preservation and management effort in Belize, will sequester more than five million tons of carbon dioxide over a 40-year period, will become economically selfsustaining after ten years, and will have substantial biodiversity benefits. 相似文献
279.
Optimizing carbon sequestration in commercial forests by integrating carbon management objectives in wood supply modeling 总被引:2,自引:0,他引:2
Charles P.-A. Bourque Eric T. Neilson Chris Gruenwald Samantha F. Perrin Jason C. Hiltz Yvon A. Blin Geoffrey V. Horsman Matthew S. Parker Christie B. Thorburn Michael M. Corey Fan-rui Meng D. Edwin Swift 《Mitigation and Adaptation Strategies for Global Change》2007,12(7):1253-1275
This paper provides a methodology for generating forest management plans, which explicitly maximize carbon (C) sequestration at the forest-landscape level. This paper takes advantage of concepts first presented in a paper
by Meng et al. (2003; Mitigation Adaptation Strategies Global Change 8:371–403) by integrating C-sequestration objective functions in existing
wood supply models. Carbon-stock calculations performed in WoodstockTM (RemSoft Inc.) are based on C yields generated from volume table data obtained from local Forest Development Survey plots
and a series of wood volume-to-C content conversion factors specified in von Mirbach (2000). The approach is used to investigate the impact of three demonstration forest-management scenarios on the C budget in a
110,000 ha forest in south-central New Brunswick, Canada. Explicit demonstration scenarios addressed include (1) maximizing
timber extraction either by clearcut or selection harvesting for greatest revenue generation, (2) maximizing total C storage
in the forest landscape and in wood products generated from harvesting, and (3) maximizing C storage together with revenue
generation. The level of clearcut harvesting was greatest for scenario 1 (≥15 × 104 m3 of wood and ≥943 ha of land per harvesting period), and least for scenario 2 (=0 m3 per harvesting period) where selection harvesting dominated. Because softwood saw logs were worth more than pulpwood ($60 m−3 vs. $40 m−3) and were strategic to the long-term storage of C, the production of softwood saw logs exceeded the production of pulpwood
in all scenarios. Selection harvesting was generally the preferred harvesting method across scenarios. Only in scenario 1 did levels of clearcut harvesting occasionally exceed those of selection harvesting, mainly in the removal of old, dilapidated
stands early in the simulation (i.e., during periods 1 through 3). Scenario 2 provided the greatest total C-storage increase over 80 years (i.e., 14 × 106 Mg C, or roughly 264 Mg ha−1) at a cost of $111 per Mg C due to lost revenues. Scenarios 3 and 1 produced reduced storage rates of roughly 9 × 106 Mg C and 3 × 106 Mg C, respectively; about 64% and 22% of the total, 80-year C storage calculated in scenario 2. The bulk of the C in scenario 2 was stored in the forest, amounting to about 76% of the total C sequestered. 相似文献
280.
Rizaldi Boer Upik R. Wasrin Perdinan Hendri Bambang D. Dasanto Willy Makundi Julius Hero M. Ridwan Nur Masripatin 《Mitigation and Adaptation Strategies for Global Change》2007,12(6):1169-1188
Rehabilitation of degraded forest land through implementation of carbon-sink projects can increase terrestrial carbon (C)
stock. However, carbon emissions outside the project boundary, which is commonly referred to as leakage, may reduce or negate
the sequestration benefits. This study assessed leakage from carbon-sink projects that could potentially be implemented in
the study area comprised of 11 sub-districts in the Batanghari District, Jambi Province, Sumatra, Indonesia. The study estimates
the probability of a given land use/cover being converted into other uses/cover, by applying a logit model. The predictor
variables were: proximity to the center of the land use area, distance to transportation channel (road or river), area of
agricultural land, unemployment (number of job seekers), job opportunities, population density and income. Leakage was estimated
by analyzing with and without carbon-sink projects scenarios. Most of the predictors were estimated as being significant in
their contribution to land use cover change. The results of the analysis show that leakage in the study area can be large
enough to more than offset the project’s carbon sequestration benefits during the period 2002–2012. However, leakage results
are very sensitive to changes of carbon density of the land uses in the study area. By reducing C-density of lowland and hill
forest by about 10% for the baseline scenario, the leakage becomes positive. Further data collection and refinement is therefore
required. Nevertheless, this study has demonstrated that regional analysis is a useful approach to assess leakage. 相似文献