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...

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...

[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...

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...

the present study was carried out in order to test the effect of grapevine rootstocks root growth on biomass and leaf nutrition status in extreme soil conditions. own rooted cuttings of rootstocks fercal, teleki kober 5bb, georgikon 28 and four new rootstock hybrids from the breeding program of georgikon faculty, hungary (fb01, jb01, zamor 17 and szf10) were grown 3 months in pots. the 5 l pots...

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 ...

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...