African sand

Sample Preparation. Two methods were used to produce sodium silicate glass samples for this study. The primary method used conventional glass melting techniques to produce compositions ranging from 12 to 21 wt. % Na20. Batch ingredients, African sand, sodiiam carbonate, and sodium nitrate, were melted at 1600 C for six hours in platinum crucibles, poured into patties and fine ground into 1 1/2" diameter discs with thickness of one to four millimeters. These anhydrous discs were fully hydrated in a one cubic foot autoclave under saturated steam conditions and stored in controlled relative hiimidity desiccators at room temperature. 

In examining vanilla beans the determination of the vanillin is a matter of importance. Busse recommends the following process for the determination 20 grams of the pods, crushed with sand, are exhausted with ether in a Soxhlet tube, and the ethereal extract is shaken out with 20 per cent, sodium bisulphite solution. From the latter, vanillin is removed by treatment with dilute H SO, the SO2 generated removed by a current of CO, and the vanillin extracted by shaking out with ether, evaporating the solvent and weighing the residue. In East African vanilla the author found 2 16 per cent, of vanillin, in that from Ceylon 1 48 per cent., and in Tahiti vanilla from 1-55 to 2 02 per cent. Tiemann and Haarman found in the best Bourbon vanilla 1 94 to 2-90 per cent., in the best Java vanilla 2 75 per cent., and in Mexican vanilla from 1-7 to 1 9 per cent. Tahiti vanilla sometimes contains less than 1 per cent, of vanilla. 

Mineral matter—when the rubber docs not contain admixtures of sand, clay, etc., owing to careless manufacture or to fraud—is present in small quantity. The best qualities (Pari) leave not more than 0 3-0-6%, but other usual qualities (Ceari, Mangabeira, Negro-head, native African and Asiatic rubbers) from x to 4%. 

N clearly contains a higher proportion of Cr than Unit B. This information suggests that the contributions from the Blue Nile (East African source) were higher during the deposition of Unit N than during the deposition of Unit B. This difference shows up only in the sand-sized fraction where the unaltered fragments of minerals from the different geological terrains are found. 

A variety from Cyprus, similar to the African, but larger and broader, globular in shape, soft on its surface, easily crumbled, and containing fine sand and pebbles. Varieties of this sort are also found pregnant with lime and conchylii. 

African iron ore (-6+12 mesh) was used as the dense bed material in the combustor and silica sand (-20+50 mesh) was used as the entrained bed material. 

The most abundant heteroatom is invariably sulfur, appearing in concentrations from below 0.1 wt. % in North African or Indonesian light crudes to over 5 wt. % in Venezuelan heavy crudes (Boscan) or Canadian tar sands. A wide variety of sulfur containing compounds are present in petroleum and refinery fractions, ranging from thiols to thiophenes the most important classes of organosulfur compounds of interest for our purposes are represented in Fig. 1.1. 

The first example is a West African field comprising a number of stacked Tertiary reservoirs. Figure 13 compares the vertical distribution of API gravity, predicted with the non-mixing model, with the field data. (The model reservoirs are a simplified representation of the reservoirs in this field in that sands that are in vertical communication are rolled into single gross reservoirs. This means that we are only looking to see... 

Flemming, B. W. 1978. Sand transport in the Agulhas current (south-east African continental margin). 

Flemming, B. 1980. Sand transport and bedform patterns on the continental shelf between Durban and Port Elizabeth (southeast African continental margin). Sedimentary Geology, 26 179-205. 

Abdominal dehiscence is common among the soldierless African species (Sands, 1972) in which the abdominal wall fractures, as a result of contraction of abdominal muscles, and the gut contents are expelled. Grasse and Noirot (1951) described columns of Anoplotermes, flanked by workers facing outward in a soldier-like manner, which were attacked by ants and killed, but subsequently rejected and were still untouched 20 h later. This suggests that their bodies contain substances noxious to ants. 

In the African development of metallurgy the Bronze Age was left out even if there is some evidence of copper manufacture in the Niger area. Iron became the first dominant metal [8.8]. Obviously there are no pictures of the oldest iron manufacture. And yet they are available When the European colonizers and missionaries reached the interior of Africa they found iron manufacturing methods that in all probability resembled the ancient techniques. Kurdufan is a province in present-day Sudan, rich in superficially situated bog ores. In 1840 an active iron-manufacturing locality was found. The furnace was a pit in the sand, about 30 cm deep. In the furnace charcoal and ore were put in layers and the charge was covered with charcoal, see Figure 8.11. 

Uranium ores vary dramatically from one site to another. In certain areas (for example, Saskatchewan, Canada, Wyoming, U.S.A., and South Australia, Australia), the ore is rich. In other areas (for example the mineral sands of Egypt, or the South African gold/uranium mines), uranium is essentially a by-product. 

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