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Sub-Saharan African countries spent on average 0.3% of their GDP on S&T (Science and Technology) in 2007. This represents a combined increase from US$1.8bn in 2002 to US$2.8bn in 2007. North African countries spend a comparative 0.4% of GDP on research, an increase from US$2.6bn in 2002 to US$3.3bn in 2007.
British Museum. Decoupage or découpage (/ ˌdeɪkuːˈpɑːʒ /; [1] French: [dekupaʒ]) is the art of decorating an object by gluing colored paper cutouts onto it in combination with special paint effects, gold leaf, and other decorative elements. Commonly, an object like a small box or an item of furniture is covered by cutouts from ...
Iron metallurgy may have been independently developed in the Nok culture between the 9th century BCE and 550 BCE. [ 5 ][ 6 ] The nearby Djenné-Djenno culture of the Niger Valley in Mali shows evidence of iron production from c. 250 BCE. The Bantu expansion spread the technology to Eastern and Southern Africa between 500 BCE and 400 CE, as ...
Africa has the longest record of human habitation in the world. The first hominins emerged 6–7 million years ago, and among the earliest anatomically modern human skulls found so far were discovered at Omo Kibish, [1] Jebel Irhoud, and Florisbad. [2][3][4][5] European archaeology, as well as that of North Africa, is generally divided into the ...
Polyacrylamide and other friction reducers decrease turbulence in fluid flow and pipe friction, thus allowing the pumps to pump at a higher rate without having greater pressure on the surface. [78] Ethylene glycol—prevents formation of scale deposits in the pipe. [78] Borate salts—used for maintaining fluid viscosity during the temperature ...
Orogenic gold deposit. An orogenic gold deposit is a type of hydrothermal mineral deposit. More than 75% of the gold recovered by humans through history belongs to the class of orogenic gold deposits. [1] Rock structure is the primary control of orogenic gold mineralization at all scales, as it controls both the transport and deposition ...
Cork is an impermeable buoyant material. It is the phellem layer of bark tissue which is harvested for commercial use primarily from Quercus suber (the cork oak), which is native to southwest Europe and northwest Africa. Cork is composed of suberin, a hydrophobic substance. Because of its impermeable, buoyant, elastic, and fire retardant ...
African wax prints, Dutch wax prints[1][2] or Ankara, [3] are a type of common material for clothing in West Africa and Central Africa. They were introduced to West and Central Africans by Dutch merchants during the 19th century, who took inspiration from native Indonesian designs. [4] They began to adapt their designs and colours to suit the ...