Concentration fluctuation measurements in clouds released from a quasi-instantaneous point source in the atmospheric surface layer     

Eugene Yee  R. Chan  P. R. Kosteniuk  G. M. Chandler  C. A. Biltoft  J. F. Bowers 《Boundary-Layer Meteorology》1994,71(4):341-373

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Measurements of level-crossing statistics of concentration fluctuations in plumes dispersing in the atmospheric surface layer     

Eugene Yee  R. Chan  P. R. Kosteniuk  G. M. Chandler  C. A. Biltoft  J. F. Bowers 《Boundary-Layer Meteorology》1995,73(1-2):53-90

The statistics of level crossings and local extremes in concentration fluctuations in plumes dispersing in the atmosphere have been investigated. A set of concentration fluctuation tracer experiments has been utilized to measure the statistical propertics of the upcrossing interval (inter-arrival time between consecutive concentration bursts), excursion duration (persistence or width of concentration bursts), and concentration amplitude (difference between the maximum and minimum concentrations between successive upcrossings) with respect to a range of concentration crossing levels. In particular, the effect of downwind distance and atmospheric stratification on the level-crossing statistics has been studied in detail. It is shown that the effect of increasing atmospheric stability on level-crossing statistics is similar to the effect of increasing distance from the source in the sense that level-crossing statistics of concentration fluctuations in stable stratification resemble those in neutral stratification, but at a greater downwind distance. It is also found that the distribution of the interval between consecutive upcrossings of a concentration level, as well as the duration of an excursion across a concentration level, can be approximated by a lognormal distribution, whereas the distribution of the concentration amplitude is best characterized by a gamma distribution. Some implications of these results for the modeling of level-crossing statistics of concentration fluctuations are discussed.  相似文献   

The difference in chemical composition of the 1962 lava from miyakezima magma reservoir in Japan     

I. Iwasaki  T. Ozawa  M. Yoshida  T. Katsura  Chan Kuk Kim  M. Aoyagi  Y. Yoshiike 《Bulletin of Volcanology》1982,45(2):81-85

Many examples of mixed magmas in banded lavas have been studied. Another type of mixed magmas or inhomogeneity of magma reservoir found in the 1962 lava flows of Miyake-zima Volcano erupted from fissures is reported.  相似文献   

Pneumatic beneficiation of coal fines using the counter-current fluidized cascade     

E.W. Chan  J.M. Beeckmans 《International Journal of Mineral Processing》1982,9(2):157-165

The counter-current gas-fluidized cascade (CFC) is a novel pneumatic device for separating mixed granular solids according to specific gravity. The possible utility of the CFC for beneficiation of coal in all size-ranges is presently under investigation, and in this paper some results are reported on pyrite beneficiation of synthetic pyrite-coal mixtures, and also on pyrite and ash beneficiation of as-received coal. The (geometric) mean particle size, by weight, of the coal used with added pyrite was 153 μm, and of the natural coal 233 μm. Preliminary results on the concentration of pyrite and ash in the reject streams indicate that CFC has some potential of being a simple and low-cost device for coal beneficiation.  相似文献   

Subliquidus glass-glass immiscibility along the albite-diopside join     

D.J. Henry  I.D.R. Mackinnon  I. Chan  A. Navrotsky 《Geochimica et cosmochimica acta》1983,47(2):277-282

A calorimetric study has shown that glasses along the albite-diopside join in the system albiteanorthite-diopside have positive enthalpies of mixing. Thermodynamic calculations based on these data describe a nearly symmetric, metastable, subliquidus irascibility gap along the join with a critical temperature at 910 K. The existence of the miscibility gap was tested experimentally by annealing an Ab₅₀Di₅₀ glass at 748 K and 823 K. Annealed glasses were examined by optical microscopy and by scanning and transmission electron microscopy. The glasses showed morphological and chemical features consistent with unmixing of two glass phases. The apparent mechanism of phase separation involves initial spinodal decomposition followed by coarsening to produce 0.1 μm–0.3 μm spherical glass phases.  相似文献   

Magnetic, Geochemical and Mineralogical Charac teristics of Soils in Qiangtang Basin, Tibet, China: Implications for Prospective Oil and Gas Land     

Liu Qingsheng Department of Geophysics  China University of Geosciences  Wuhan  The State Key Laboratory of Oil/Gas Reservoir Geology  Exploitation of China  Institute of Chengdu Technology  Chengdu Wu Qifan Li Haixia Department o 《中国地质大学学报(英文版)》2001,12(2)

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Methane in an acidic bog lake: The influence of peat in the catchment on the biogeochemistry of methane   总被引：3，自引：0，他引：3  

Peter Casper  On Chim Chan  Andre L. S. Furtado  Donald D. Adams 《Aquatic Sciences - Research Across Boundaries》2003,65(1):36-46

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Phthalate ester plasticizers,DDT, DDE and polychlorinated biphenyls in biota from the Gulf of Mexico     

C.S Giam  H.S Chan  G.S Neff 《Marine pollution bulletin》1978,9(9):249-251

The levels of phthalate ester plasticizers, DDT, DDE and polychlorinated biphenyls (PCBs) were determined in the tissues of 18 species of marine organisms from the northwestern Gulf of Mexico. Low levels of the most widely used phthalate, di-(2-ethylhexyl) phthalate, were found in the majority of the samples; no other phthalates were detected. DDT, DDE and PCBs were found in all samples, but at somewhat lower levels than those found in our 1971 survey. A decrease in p,p′-DDT/p,p′-DDE ratios relative to 1971 was also noted.  相似文献   

Effects of bottom sediments on the survival of Enterobacter aerogenes in seawater     

Kwong-Yu Chan  S.H. Wong  C.Y. Mak 《Marine pollution bulletin》1979,10(7):205-210

The survival of the coliform bacterium Enterobacter aerogenes in seawater was greatly affected by the underlying bottom sediments. The presence of sediments which contained higher concentrations of organic nutrients than the overlaying seawater prolonged the survival and even enabled growth of the bacterial cells. Results obtained from chemical analysis indicated that sediments of fine-grained, silt-clay type contained highest amounts of organic nutrients as compared with sediments with larger particle sizes such as silt and sand grains. Thus, nutrient contents of the sediments were found to be inversely proportional to sediment particle size. The degree of prolonged survival of E. aerogenes was also found to be inversely proportional to the size of the sediment particles presented. Release of the bound nutrients which became available to cells of E. aerogenes from sediments by action of waves and human activities can explain, at least in part, why high counts of coliform bacteria are obtained in coastal and beach waters.  相似文献   

Electromagnetic induction in the San Juan Bay region of Vancouver Island     

G.H. Chan  H.W. Dosso  L.K. Law 《Physics of the Earth and Planetary Interiors》1981,27(2):114-121

The response of the electric and magnetic field variations over the San Juan Bay region of Vancouver Island is studied using a scaled laboratory analogue model. The laboratory frequencies simulate periods of 10 and 100 s in the geophysical problem. The model results indicate that, for both E- and H-polarization of the source field, induced current in the ocean is deflected around Cape Flattery and channelled into the Juan de Fuca Strait. With increasing period, the proportion of current channelled into the Strait decreases sharply. Induced current in the strait is also funnelled into San Juan Bay, a finger-shaped bay ca. 4 km wide and 7.5 km long, for both polarizations of the source field. The effect of the Bay on the field response is confined to the local region, within approximately 6 km of the centre of the Bay. Good agreement between field station and analogue model H_z results was obtained for the San Juan Bay. The behaviour of the Parkinson arrow for these two stations is examined with the aid of the analogue model results.  相似文献