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401.
402.
用季胺盐作萃取剂,采用一级萃取回收废催化剂中的钼,其钼回收率可达90%,反萃液可直接得到四钼酸铵,工艺简单,操作方便,具有显著的经济效益和一定的环境效益。 相似文献
403.
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
404.
405.
赤峰市科尔沁沙地重要生态功能保护区生态环境现状评价及可持续发展战略探讨 总被引:1,自引:0,他引:1
本文对科尔沁沙地生态环境特点、现状、生态环境恶化的主要原因及对经济、社会和环境产生的影响进行了评价,并提出了科尔沁沙地经济、社会可持续发展的对策及发展战略,为全面落实《全国生态保护纲要》提供依据。 相似文献
406.
407.
408.
观音阁水库水体中氮、磷污染现状及其防治对策 总被引:1,自引:0,他引:1
孟凡青 《辽宁城乡环境科技》2006,26(4):13-15
本文通过对观音阁水库的水质进行监测和调查分析,了解观音阁水库水体中氮、磷污染状况及来源。根据监测和调查结果可以判断,磷是观音阁水库中限制性营养盐。通过采取必要的防治对策和措施,控制氮、磷的浓度,不仅可以控制观音阁水库水体富营养化程度,而且还能产生一定的经济效益。 相似文献
409.
Dermatas D Dadachov M Mirabito M Meng X 《Journal of the Air & Waste Management Association (1995)》2003,53(11):1363-1372
Artificially contaminated (spiked) natural soils were solidified/stabilized using various combinations of commonly used additives, such as lime, cement, fly ash, activated carbon, and silica fume. The effectiveness of the solidification/stabilization (S/S) processes was evaluated based on experimental findings from compaction testing, unconfined compressive shear strength, and X-ray diffraction (XRD). Correlations of limited reliability between unconfined compressive strength and penetrometer and torvane measurements were derived. Results from XRD experiments indicated that certain organic contaminants (i.e., naphthalene and pyrene) might impact the S/S processes for a given combination of additives. The type and amount of organic contaminants also affected the pozzolanic reactions. Specifically, the absence or small peak intensity of pozzolanic product XRD patterns for a given combination of additives was a good indication that the type and the amount of organic contaminant present inhibited pozzolanic reactions. This phenomenon was tested and confirmed for actual field-contaminated samples. 相似文献
410.
To demonstrate conformity of transportation projects to National Ambient Air Quality Standards in accordance with State Implementation Plans, the U.S. Environmental Protection Agency (EPA) uses intersection level of service (LOS) as one of its major criteria for screening for potential carbon monoxide (CO) hotspots. Although intersection LOS is a measure of traffic volume, signal timing, and related congestion and delay, the assigned level reflects only the computed averaged stopped delay (ASD) per vehicle at the intersection. Thus, intersections can often operate at the same LOS but produce vastly different levels of predicted CO concentrations. For example, a two-lane approach operating at LOS D will produce very different levels of CO than a five-lane approach also operating at LOS D. This study explores the effectiveness of the LOS D criterion as a screen for identifying potential CO hotspots. The study results indicate that LOS is a poor predictor of potential CO hotspots when compared to results generated with the EPA-recommended micro-scale model CAL3QHCr. To more consistently screen out those intersections that will not be identified as CO hotspots using the micro-scale models, a new criterion, equivalent red-time vehicles (ERTV), is introduced. The modeling results using ERTV suggest that it is a more robust measure for identifying potential CO hotspots, and conversely, screening out those intersections that are not likely to be identified as hotspots using micro-scale simulation results. 相似文献