Coalbed methane producibility from the Mannville coals in Alberta, Canada: A comparison of two areas   总被引：2，自引：1，他引：1  

T. Gentzis  F. Goodarzi  F.K. Cheung  F. Laggoun-Dfarge 《International Journal of Coal Geology》2008,74(3-4):237-249

Selenium concentrations were measured in five rock cores from a mine in Boone County, West Virginia to determine their relationship to sulfur, rock type and stratigraphic location. The samples spanned the Winifrede and Coalburg coal beds of the Middle Pennsylvania upper Kanawha Formation and included coals and clastic lithologies. The coals generally contained the highest concentrations of Se and the sandstones the lowest. No correlation was observed between total Se and sulfur concentrations for either the entire data set or for individual lithologies. Better correlations were identified for log concentrations between total Se and total organic carbon. Principal component analysis identified a strong sulfur–acid component, interpreted to be due to sulfide mineral presence, which correlates well with S but not with Se. Coal sample chemistry is more likely to load onto this component while clastic rock chemistry is more likely to load onto the second, non-sulfur component. Se concentrations load onto both components indicating they are not controlled by a single overriding chemistry. Selective extractions indicate that Se is distributed between both sulfide and organically-bound fractions, as defined by the test. Overall, the lack of correlation between Se and S, the distribution of Se among extracted fractions, and the loading of Se onto both sulfur and non-sulfur components support that the Se in these rock layers is distributed in more than one chemically-bound form. Non-coal rock units with the highest concentrations of Se were found adjacent to coal beds, suggesting that redistribution of Se may have occurred post-deposition. The acidic domed swamps that formed these coals were low in sulfur and a reasonable chemical setting to accumulate Se if it were introduced. The preservation of Se in the domed swamp peat coupled with post-depositional redistribution may partly explain the data presented.  相似文献   

Energetics and dynamics associated with two typical mobile trough pathways over East Asia in boreal winter     

Marco Yu-Ting Leung  Hoffman Ho-Nam Cheung  Wen Zhou 《Climate Dynamics》2015,44(5-6):1611-1626

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Major ion and isotope geochemistry of fluids and gases from coalbed methane and shallow groundwater wells in Alberta,Canada     

Katrina Cheung  Patrick Klassen  Bernhard Mayer  Fariborz Goodarzi  Ramon Aravena 《Applied Geochemistry》2010

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Effects of nitrogen and sulphide on macroinfaunal community: a microcosm study     

Shin PK  Cheung CK  Cheung SG 《Marine pollution bulletin》2006,52(11):1333-1339

A microcosm experiment was conducted to test the short-term effects of nitrogen (as TKN, total Kjeldahl nitrogen) and sulphide (as AVS, acid volatile sulphide) on macrobenthic infauna over a period of 8 weeks. The experiment consisted of four treatments using sediment cores (D: 8 cm, H: 20 cm) with addition of: I, nitrogen (N) to an in situ mean level of 0.48 mg Ng(-1) dw; II, sulphidic solution (S) to an in situ mean level of 318.8 microM S g(-1) dw; III, nitrogen and sulphidic solution (NS) to in situ mean levels of 0.45 mg Ng(-1) dw and 329.0 microM S g(-1) dw, respectively, and IV, control with no addition of N and S. Sediment cores were retrieved for analysis of infaunal composition after weeks 2, 4 and 8. A total of 646 specimens of macrobenthic infauna belonging to 27 species were recorded from the cores, in which polychaetes were the most abundant with respect to species and individual numbers. Mean species number and diversity H' of the control and N treatment was statistically higher than S and NS treatments, mean individual number of the S treatment was larger than the NS treatment, and mean evenness J of the S treatment was lower than the N and NS treatments as well as the control. Individual numbers also showed a significant increase from weeks 2 to 8, whereas evenness J decreased in weeks 4 and 8. Multivariate analyses of the faunal data suggested that benthic composition of the N treatment and control did not differ during the experimental period, but changes in benthic structure in S and NS treatments were evident. The present findings demonstrated the dose-response relationship of benthic species changes under controlled addition of N and S. The response to N and S additions in the sediment microcosms was in agreement with the general effects of organic enrichment on macrobenthic communities along a spatial gradient of organic pollution as described by Pearson and Rosenberg [Pearson, T.H., Rosenberg, R., 1978. Macrobenthic succession in relation to organic enrichment and pollution of the marine environment. Oceanography and Marine Biology Annual Review 16, 229-311]. However, in the present experiment, community changes in the treatments were observable in a short, temporal scale.  相似文献   

Baseline data of subtropical coral communities in Hoi Ha Wan Marine Park, Hong Kong, obtained by an underwater remote operated vehicle (ROV)     

Lam K  Shin PK  Bradbeer R  Ku KK  Hodgson P  Cheung SG 《Marine pollution bulletin》2007,54(1):107-112

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A clash of values and approaches: A case study of marine protected area planning in Mozambique     

Sérgio Rosendo  Katrina BrownAlison Joubert  Narriman JiddawiMicas Mechisso 《Ocean & Coastal Management》2011,54(1):55-65

Many developing countries are expanding their network of Marine Protected Areas (MPAs) to meet ambitious marine conservation targets set globally and to develop tourism nationally. This study explores the human dimensions of MPA planning in Mozambique by engaging local resource users in a series of structured discussions about marine resource use, pressures on marine resources, ways to address such pressures, and the potential positive and negative impacts of MPAs on the management of marine resources and livelihoods, from a community perspective. Findings show that the groups and communities interviewed are at best ambivalent towards MPAs while at the same time supporting increased government regulation, including conventional fisheries management measures. The study suggests that without significant community involvement in the choice of marine conservation tools, the drive to establish MPAs to achieve biodiversity conservation and tourism development goals may be counterproductive, at least in terms of poverty alleviation and sustainable resource use. It argues that a wider range of marine conservation approaches and tools needs to be considered in addition to MPAs, taking into consideration local views and institutional capacities.  相似文献   

An analytical technique for evaluation of coupled heat and mass flow coefficients in unsaturated soil     

R. N. Yong  D. M. Xu  A. M. O. Mohamed  S. C. H. Cheung 《国际地质力学数值与分析法杂志》1992,16(4):233-246

This study was done to evaluate a phenomenological approach for determining the coupled heat and water diffusion parameters. This technique requires the use of both theory and experimental data. The transport equation was solved analytically using nondimensional analysis. The calculated diffusion parameters of a compacted sand–bentonite-based material are presented. The agreement between the back calculated values and the experimental volumetric water content profiles was good. Practical application of the technique is also discussed.  相似文献   

Graph-assisted landscape monitoring     

Alan Kwok Lun Cheung  David O’sullivan  Gary Brierley 《International journal of geographical information science》2013,27(4):580-605

The structure of computational spatial analysis has mostly built on data lattices inherited from cartography, where visualization of information takes priority over analysis. In these framings, spatial relationships cannot easily be encoded into traditional data lattices. This hinders spatial analysis that emphasizes how interactions among spatial entities reflect mutual inter-relationships. This paper explores how graph theoretic principles can support spatiotemporal analysis by enabling assessment of spatial and temporal relationships in landscape monitoring.  相似文献   

Heliophysics Event Knowledgebase for?the?Solar Dynamics Observatory (SDO) and Beyond     

N. Hurlburt  M. Cheung  C. Schrijver  L. Chang  S. Freeland  S. Green  C. Heck  A. Jaffey  A. Kobashi  D. Schiff  J. Serafin  R. Seguin  G. Slater  A. Somani  R. Timmons 《Solar physics》2012,275(1-2):67-78

The immense volume of data generated by the suite of instruments on the Solar Dynamics Observatory (SDO) requires new tools for efficient identifying and accessing data that is most relevant for research. We have developed the Heliophysics Events Knowledgebase (HEK) to fill this need. The HEK system combines automated data mining using feature-detection methods and high-performance visualization systems for data markup. In addition, web services and clients are provided for searching the resulting metadata, reviewing results, and efficiently accessing the data. We review these components and present examples of their use with SDO data.  相似文献   

Effects of salinity on anatomical features and physiology of a semi-mangrove plant Myoporum bontioides     

H.M. Xu  N.F.Y. Tam  Q.J. Zan  M. Bai  P.K.S. Shin  L.L.P. Vrijmoed  S.G. Cheung  W.B. Liao 《Marine pollution bulletin》2014

The effect of different concentrations of NaCl, 0, 100, 200, 300 and 400 mM, on the anatomical features and physiology of Myoporum bontioides was investigated. The photosynthetic rates (Pn) were significantly reduced by salt stress, with the lowest values at 400 mM NaCl. The content of malondialdehyde (MDA), proline and soluble sugar, as well as the activities of peroxidase (POD) and catalase (CAT) increased at the beginning, but became similar to the control as the experiment proceeded. The NaCl effect on superoxide dismutase (SOD) was different from the other parameters, with a significant reduction at 400 mM NaCl at Day 7. Salt glands were found in both upper and lower epidermis, and the ratios of the thickness of palisade to spongy mesophyll tissues increased with NaCl concentrations. The medullary ray was clearly damaged by NaCl at levels of 200 and 300 mM. These results demonstrated that M. bontioides could adapt to a relatively low salinity, and was not a halophilous species.  相似文献