Olea capensis wood materials. It is also the one of the world's hardest woods according to the Janka hardness test. The timber has a good abrasion resistance and is very strong. It is an excellent turnery wood, and is used for a wide range of decorative items. Olea capensis Olea capensis, also known by the common name black ironwood, is an African tree species belonging to the Olive family (Oleaceae). It is widespread in Sub-Saharan Africa from the east in Somalia, Ethiopia and Sudan, south to the tip of South Africa, and west to Cameroon, Sierra Leone and the Islands of the
Carbonate hardness [milli[equivalent]s] per litre (meq/L) or ppm. Carbonate hardness expressed in ppm does not necessarily equal carbonate alkalinity expressed in ppm. formula_1 whereas formula_2 However, for water with a pH below 8.5, the CO will be less than 1% of the HCO so carbonate alkalinity will equal carbonate hardness to within an error of less than 1%. In a solution where only CO affects the pH, carbonate hardness can be used to calculate the concentration of dissolved CO in the solution with the formula CO = 3 × KH × 10, where KH is degrees of carbonate hardness and CO is