نتایج جستجو برای: layered gravel

تعداد نتایج: 37400  

2004
S. Schweizer

Decisions about flood protection and river rehabilitation require prediction of the consequences of each possible management alternative. To provide such predictions, an integrative model is required that represents the cause-effect relations between revitalisation measures and morphologic, hydraulic and ecological consequences. This paper describes the hydraulics submodel of such an integrativ...

2010
P. Y. Julien C. K. Chang

The 2003 flood of the Muda River reached 1,340 m3 /s at Ladang Victoria and adversely impacted 45,000 people in Malaysia. A flood control remediation plan proposed a levee height based on a 50-year discharge of 1 ,815 m3 /s obtained from hydrologic models. This design discharge falls outside the 95% confidence intervals of the flood frequency analysis based on field measurements. Instream sand ...

ژورنال: آبخیزداری ایران 2020

Surface gravel cover is an important factor for contoroling of soil erosion in dry area specially in area that plant can not grow because of excessive dryness and salinity. The objective of this study was investigation effect of different surface gravel cover on runoff and sediment yeild. For this porpose, 36 field plots with 20 meter length and 0.5 meter width at 3 percent slope were construct...

2013
E. E. Adiotomre

Submitted: Jul 12, 2013; Accepted: Aug 26, 2013; Published: Aug 29, 2013 Abstract: Sand production in water, oil and gas wells is usually controlled by gravel packing techniques worldwide. Consideration in the gravel pack design requires that the particle size is five or six times the formation sand depending on the formation sand median diameter. Sieve analysis result shows that the grain size...

Journal: :Applied and environmental microbiology 2016
Andries J van der Walt Riegardt M Johnson Don A Cowan Mary Seely Jean-Baptiste Ramond

UNLABELLED Fairy circles (FCs) are barren circular patches of soil surrounded by grass species. Their origin is poorly understood. FCs feature in both the gravel plains and the dune fields of the Namib Desert. While a substantial number of hypotheses to explain the origin and/or maintenance of fairy circles have been presented, none are completely consistent with either their properties or thei...

2013
Manuel Muñoz Alcobendas Eduardo Munera Sánchez Francisco Blanes José-Enrique Simó-Ten

In this work is presented a general architecture for a multi physical agent network system based on the coordination and the behaviour management. The system is organised in a hierarchical structure where are distinguished the individual agent actions and the collective ones linked to the whole agent network. Individual actions are also organised in a hybrid layered system that take advantages ...

2010
Michael Bliss Singer

[1] The first extensive dataset on subaqueous bed material grain size in a large river subject to reduced sediment supply is investigated alongside bathymetry, modeled flow, and sediment flux. Results suggest that following sediment supply decline and a shift to a finer sediment supply, the gravel‐sand transition (GST) in fluvial systems extends and subsequently migrates upstream. The non‐abrup...

2011
N. Khezri H. Chanson

Abstract: A tidal bore is a positive surge taking place during the flood tide under macro-tidal conditions and the bore represents the leading edge of the tidal wave propagating upstream. The fundamentals of tidal bores remain unknown, although some physical experiments were performed during the last two decades. In this study, some physical modelling was performed to investigate the tidal bore...

2000
R. K. Rowe

Local strain measurements opposite gravel contacts and around a single isolated perforation are reported for a high-density-polyethylene pipe (320 mm outside diameter, 32 mm thick) typical of that commonly used as part of the leachate collection system in municipal solid waste landfills. Emphasis is given to examining the localized effect of coarse gravel contacts on pipe strain and the strain ...

2009
Mengzhi CHEN Yingying TANG Xianpo LI Zhaoxiang YU

In this study constructed wetlands (CWs) were used to remove three heavy metals (Zn, Cu and Pb). The two tested substrates were made of coke and gravel, respectively. First order dynamic model was appropriate to describe removing of Zn and Cu. The experimental results showed that first dynamic removal rate constants of Zn in CWs with coke and gravel were 0.2326 h and 0.1222 h, respectively. And...

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