نتایج جستجو برای: sand mining
تعداد نتایج: 114337 فیلتر نتایج به سال:
Abstract Numerical models for calculating bottom morphology are increasingly popular because of their long-term forecasting capabilities as well ability to identify causes. However, the simulation morphology, in addition natural factors, is also governed by economic activities, especially sand mining. In this paper, we propose development numerical model curvilinear coordinates combined with a ...
Offshore activities often encounter large scale sand patterns, such as sand waves. Sand waves are offshore bed forms occurring at water depths of 10 to 50 m. Their wavelengths can lead up to 500 m and their heights are typically several metres. Furthermore, sand waves have been shown to migrate, with typical velocities of up to metres per year. These dynamic sand waves decrease the least naviga...
BACKGROUND Beach sand can harbor fecal indicator organisms and pathogens, but enteric illness risk associated with sand contact remains unclear. METHODS In 2007, visitors at 2 recreational marine beaches were asked on the day of their visit about sand contact. Ten to 12 days later, participants answered questions about health symptoms since the visit. F+ coliphage, Enterococcus, Bacteroidales...
Mining activities can endanger the stability of hydraulic structures. Numerical modeling local scouring around hydrodynamic and circular bridge pile groups, due to action clear water conditions via non-cohesive sediment, was performed using a computational fluid dynamics (CFD) model, large eddy simulation (LES) turbulence van Rijn sedimentary model with FLOW-3D software. The groups were positio...
The use of cemented Aeolian sand-fly ash backfill (CAFB) material to fill the mining area improve surface subsidence damage caused by underground coal is in development stage. Their performance with large overflow water and strength loss not well understood. Few research has been conducted understand effects aeolian sand gangue on rheological properties CAFB plasticizers. Therefore, this study ...
Previous research has shown that the temperature of underlying permafrost decreases after the ground surface is covered with sand. No significant conclusions have yet been drawn that explain why this happens, because the heat transfer mechanism effects of the sand layer on the underlying permafrost remain unclear. These mechanisms were studied in the present work. We found that the upward short...
In the evolution processes of wind blown sand movement and aeolian geomorphology, it always contains some complex behaviors, for example, the nonlinear character of turbulence and attractors, the stochastic character of wind gust, liftoff and movement of sand, the interaction among wind field, sand movement, electric field in wind blown sand flux and thermal diffusion, multi-scale character fro...
Straw checkerboard barrier (SCB) is the most representative antidesertification measure and plays a significant role in antidesertification projects. Large-eddy simulation and discrete-particle tracing were used to numerically simulate the wind sand movement inside the straw checkerboard barrier (SCB), study the movement characteristics of sand particles, find the transverse velocities of sand ...
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