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971.
A model is developed to predict annual and total above-ground carbon storage within a hybrid poplar stream buffer. The regression model predicts tree wet weight based upon circumference at breast-height (137 cm) with an r-square value of 0.9922. Carbon storage in above-ground biomass is estimated to be 3.57 to 3.71 metric tons per hectare, with a measured annual increment of 0.92 to 1.37 metric ton per hectare per year. The variability of carbon storage within this biological system, including soil organic matter, is explored, and the number of samples required to achieve a desired level of statistical certainty are predicted. As has been investigated previously for other biological systems (Garten and Wullschleger, 1999), the study shows that a prohibitively large number of samples must be taken in order to achieve high degrees of certainty about mean carbon storage values. The study also shows, however, that mean values with somewhat greater uncertainties can easily be achieved with much smaller sample sizes. Thus carbon sequestration verification might be accomplished cost-effectively if the degree of certainty required is not unrealistically high for highly variable natural systems. 相似文献
972.
Richard P. Haynes 《Journal of Agricultural and Environmental Ethics》2006,19(4):335-336
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This paper presents the results of an evaluation of excessive salt emissions from 16 hogged fuel boilers in Washington, Oregon, and Alaska. Logs transported or stored in sea water, absorb substantial amounts of salt which is noncombustible, and is emitted as a fine particulate when the hogged fuel is burned, contributing to opacity and particulate emissions. Control measures considered are fuel pretreatment, combustion modification, use of conventional particulate control devices (electrostatic precipitators, fabric filters, and wet scrubbers), and several novel particulate control devices.The best available control technology appears to be a mechanical collector-fabric filter combination; some electrostatic scrubber type devices have also shown excellent capability. 相似文献
977.
Richard Zeckhauser 《Journal of Environmental Economics and Management》1981,8(3):215-237
A theory of effective policy choice is developed that recognizes that the probability that a policy is adopted depends on who gains from it, who loses, and by how much. Ten pieces of recent environmental legislation are assessed to see how mechanisms such as coupling with other legislation, phased implementation, and the manipulation of uncertainty can spread benefits and costs. Several optimizing models are presented that explicitly incorporate the probability of adoption. 相似文献
978.
A sex-linked recessive lethal test was performed on male fruit flies of the species Drosophila melanogaster, (Oregon-R strain), exposed to an approximate five-fold dilution of exhaust from a diesel engine. The eight hour exposure was achieved by drawing diluted diesel exhaust from a three cubic meter stainless steel exposure chamber housing laboratory animals through a two liter reaction flask modified for use with Drosophila. A preconditioned sampling bag was used to collect the emissions after passing through the exposure chamber containing the flies. Results of analyses performed on the diesel exhaust mixture showed the following: carbon dioxide—0.17%, carbon monoxide—12.2 ppm, hydrocarbons—11.6 ppm, nitrogen oxide—3.8 ppm, nitrogen dioxide—2.9 ppm, sulphur dioxide—1.0 ppm, and particulates—2.18 mg/m3. Two broods of the F2 generation were investigated for the occurrence of recessive lethal events. These broods approximated the developing gametogenic stages of mature sperm (P1 matings on days 2 and 3 postexposure) and spermatocytes (P1 matings on days 8 and 9). Additionally, the F3 generation was evaluated for the occurrence of mosaic recessive lethal events which might escape detection in the F2 generation. An equal number of F2 and F3 flies for both broods served as concurrent controls. Results indicate that, under the conditions tested, the diesel exhaust did not increase the mutation frequency of the exposed flies (F2 rate = 0.30%, F3 rate = 0%) when compared to the concurrent controls (F2 rate = 0.37%, F3 rate = 0.15%). 相似文献
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