Sand is a vital ingredient for modern structures and to meet demand, a substantial volume of sand is extracted illegally from riverbeds globally. The Vietnamese Mekong Delta is one of the largest delta in Asia and it has a long history of riverbed s
Sand and gravel is dredged from the seabed in various parts of the world for, among other things, land reclamation, concreting aggregate, building sand, beach nourishment, and coastal protection. The largest producer in the world is Japan at around 80–100 Mm3 per year, Hong Kong at 25–30...
[56]. M20 grade of concrete, is the mix ratio of cement, sand and aggregates of 1:1.5:3 in volume. Guney (2010) found concrete with 10% waste foundry sand exhibits almost similar results to that of the control one [57]. View article Related terms: Silicate Aluminum Carbon Dioxide ...
Sand seas are some of the least hospitable domains of Earth’s surface; the atmosphere is dry and windy with extreme diurnal cycles1and the land is barren and erodible2. Spanning 100–600,000 km2, sand seas (or ergs) host the largest expanses of repeating patterned topography on the planet...
Land evaluation for afforestation in a semi-arid environment: The montane plains of the Central Highlands of North Yemen In semi-arid environments, much land use depends on water harvesting from the upper members of soil catenas to support crops on the lower members. In the C... D Dent,R...
Made for digging, scooping, sifting, pouring, and molding, sand toys help build fine motor skills, gross motor development, and eye-hand coordination in kids. Sand toys also help kids gain an understanding of volume and capacity and they teach kids how different elements like sand and water ...
Coastal erosion threatens coastal land which is an invaluable limited resource to Small Island Developing States (SIDS). Columbus Bay, located on the south-western peninsula of Trinidad, experiences high rates of coastal erosion which has resulted in the loss of millions of dollars to coconut estat...
even as its volume diminishes. Sand-glasses came into use in part because of the need to measure time at sea, far from any landmark; speed would be measured by counting the number of knots in a rope paid out from the back of the ship in the time it took for the sand to run throu...
As the name implies, slow sand filters are operated at low filtration rates, typically 0.1–1 m/h. (Note: filtration rate is usually expressed as approach velocity, e.g. m/h, which is equivalent to a volume flow rate per unit area, m3/m2h.) Slow sand filters use rather fine sand ...
Over several years, gains or losses in the total sand volume (integrated from the back beach to 8 m depth, over the few km alongshore survey spans) are sometimes comparable to nourishment volumes, suggesting relatively large interannual sediment fluxes across the control volume boundaries. The ...