نتایج جستجو برای: sediment particle

تعداد نتایج: 210022  

2010
JACK LEWIS

Automated data collection is essential to effectively measure suspended sediment loads in storm events, particularly in small basins. Continuous turbidity measurements can be used, along with discharge, in an automated system that makes real-time sampling decisions to facilitate sedi­ ment load estimation. The Turbidity Threshold Sampling method distributes sample collection over the range of r...

2002
J. Talley U. Ghosh R. Luthy R. Valente

This work applied new investigative techniques to assess the locations, distributions, and associations of polycyclic aromatic hydrocarbons (PAHs) in dredged harbor sediment. Dredged materials from the Milwaukee Confined Disposal Facility were collected and homogenized to provide sufficient sample for four month bioslurry treatment testing and for PAH analyses on various size and density fracti...

2016
Kurt Imhoff Marco P. Maneta Andrew Wilcox

Sediment routing in gravel-bed rivers refers to the intermittent transport and storage of bedload particles, where short-duration steps are separated by periods of inactivity. Channel morphology governs sediment routing, but morphologic effects on routing in headwater systems are not well understood compared to lowland systems. RFID tracers are a valuable tool that can be employed to characteri...

Journal: :Environmental science & technology 2003
J V K Kukkonen P F Landrum S Mitra D C Gossiaux J Gunnarsson D Weston

Measures of desorption are currently considered important as potential surrogates for bioaccumulation as measures of the bioavailability of sediment-sorbed contaminants. This study determined desorption rates of four laboratory spiked compounds, benzo[a]pyrene (BaP), 2,4,5,2',4',5'-hexachlorobiphenyl (HCBP), 3,4,3',4'-tetrachlorobiphenyl (TCBP), and pyrene (PY), to evaluate the effect of sedime...

Journal: :Environmental science & technology 2003
Upal Ghosh John R Zimmerman Richard G Luthy

This research provides particle-scale understanding of PCB and PAH distribution in sediments obtained from three urban locations in the United States: Hunters Point, CA; Milwaukee Harbor, WI; and Harbor Point, NY. The sediments comprised mineral grains (primarily sand, silt, and clays) and carbonaceous particles (primarily coal, coke, charcoal, pitch, cenospheres, and wood). The carbonaceous se...

2009
Nian-Sheng Cheng

Whether or not a sediment particle is entrained from a channel bed is associated with both average bed shear stress and shear stress fluctuation, the latter being flow-dependent and also related to bed irregularities. In the first part of this study, a preliminary analysis of possible fluctuations induced by bed roughness is presented for the case of immobile plane bed comprised of unisized sed...

Journal: :Science 1954
B R Colby C H Hembree

A natural chute in the Niobrara River near Cody, Nebr., constricts the flow of the river except at high stages to a narrow channel in which the turbulence is sufficient to suspend nearly the total sediment discharge. Because much of the flow originates in the sandhills area of Nebraska, the water discharge and sediment discharge are relatively uniform. Sediment discharges based on depth-integra...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1984
M T DeBanne M Bolyos J Gauldie E Regoeczi

Analyses by differential centrifugation of liver homogenates from rats that had received 131I-labeled asialoorosomucoid showed that, 1 min after injection, most of the intracellular ligand was associated with a particle that did not sediment at 2.5 X 10(5) g-min. However, by 10 min, undigested ligand became associated with a particle that did sediment at this speed. On analytical ultracentrifug...

Journal: :مرتع و آبخیزداری 0
سادات فیض نیا استاد دانشکدة منابع طبیعی دانشگاه تهران سهیلا یونس زاده جلیلی کارشناس ارشد دانشکدة منابع طبیعی دانشگاه تهران حسن احمدی استاد گروه آبخیزداری دانشگاه آزاد اسلامی، واحد علوم و تحقیقات تهران

due to difficulties in the application of traditional methods for identifying sediment sources, fingerprinting techniques, based on physical, chemical and organic properties of sediment and source materials, are increasingly being used as a valuable and effective alternative approach to obtain such information. the first step in this method is using an appropriate combination of diagnostic prop...

2005
Valerie Partridge Sandra Aasen Kathy Welch

PSAMP Long-term Sediment Monitoring As part of the Puget Sound Ambient Monitoring Program (PSAMP), the Washington State Department of Ecology sampled sediments at ten fixed stations each spring from 1989 through 2000 (Figure 1). Stations were chosen from a variety of habitats and geographic locations in Puget Sound. Sediments from each station were analyzed for particle size, organic carbon con...

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