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River

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Articles 31 - 33 of 33

Full-Text Articles in Social and Behavioral Sciences

Minimum Energy As The General Form Of Critical Flow And Maximum Flow Efficiency And For Explaining Variations In River Channel Pattern, He Qing Huang, Howard H. Chang, Gerald Nanson Jan 2004

Minimum Energy As The General Form Of Critical Flow And Maximum Flow Efficiency And For Explaining Variations In River Channel Pattern, He Qing Huang, Howard H. Chang, Gerald Nanson

Faculty of Science, Medicine and Health - Papers: part A

Although the Bélanger-Böss theorem of critical flow has been widely applied in open channel hydraulics, it was derived from the laws governing ideal frictionless flow. This study explores a more general expression of this theorem and examines its applicability to flow with friction and sediment transport. It demonstrates that the theorem can be more generally presented as the principle of minimum energy (PME), with maximum efficiency of energy use and minimum friction or minimum energy dissipation as its equivalents. Critical flow depth under frictionless conditions, the best hydraulic section where friction is introduced, and the most efficient alluvial channel geometry …

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Changing Ecological Concerns In Rock-Art Subject Matter Of North Australia's Keep River Region, Paul Tacon, Ken Mulvaney, Sven Ouzman, Richard L. Fullagar, Lesley M. Head, Paddy Carlton Jan 2003

Changing Ecological Concerns In Rock-Art Subject Matter Of North Australia's Keep River Region, Paul Tacon, Ken Mulvaney, Sven Ouzman, Richard L. Fullagar, Lesley M. Head, Paddy Carlton

Faculty of Science - Papers (Archive)

The Keep River region has a complex body of engraved and painted rock-art, distinct from but with links to regions to the east, west and south. At least four major periods of figurative rock-art have been identified with differing subject matters and ages. Significant changes in depictions of human figures and animals are evident, reflecting shifts in emphasis associated with ecological concerns and environmental change. We flesh out the relative rock-art chronology by highlighting these changes, from worlds dominated by humans to those dominated by mammals and birds, and finally to a recent world of reptiles and humans. Symbolic aspects …

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Identification Of Cryptosporidium Oocysts In River Water, Jerry Ongerth, Henry Stibbs Jan 1987

Identification Of Cryptosporidium Oocysts In River Water, Jerry Ongerth, Henry Stibbs

Faculty of Engineering and Information Sciences - Papers: Part A

Water samples were collected from four rivers in Washington State and two rivers in California and examined for the presence of Cryptosporidium oocysts. Oocyst-sized particles were concentrated from 20-liter samples of water by membrane filtration, centrifugation, and differential sedimentation. The particle concentrate was then deposited on a 25-mm-diameter membrane filter for oocyst identification by indirect immunofluorescence assay. The identification procedure had a limit of detection of about five oocysts per liter. Cryptosporidium oocysts were found in each of 11 river water samples examined. Concentrations ranged from 2 to 112 oocysts per liter. The finding of Cryptosporidium oocysts in all samples …

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