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Limited medical use in drugs such as strontium ranelate. Non-toxic; in humans, it often substitutes for calcium. [11] sulfur: 16: 5: Sulfur is essential and ubiquitous, partly because it is part of the amino acids cysteine and methionine. Many metals that appear as enzyme cofactors are bound by cysteine, and methionine is essential for protein ...
The use of polished stone axes marks a significant advance, because a much wider variety of rocks could serve as tools. A late Bronze Age sword- or dagger-blade. The innovation of smelting and casting metals in the Bronze Age started to change the way that cultures developed and interacted with each other.
Aluminium (or aluminum) metal is very rare in native form, and the process to refine it from ores is complex, so for most of human history it was unknown. However, the compound alum has been known since the 5th century BCE and was used extensively by the ancients for dyeing .
The Bayer process is the principal industrial means of refining bauxite to produce alumina (aluminium oxide) and was developed by Carl Josef Bayer.Bauxite, the most important ore of aluminium, contains only 30–60% aluminium oxide (Al 2 O 3), the rest being a mixture of silica, various iron oxides, and titanium dioxide. [1]
Gold–aluminium intermetallic have different properties from the individual metals, such as low conductivity and high melting point depending on their composition. Due to the difference of density between the metals and intermetallics, the growth of the intermetallic layers causes reduction in volume, and therefore creates gaps in the metal ...
A knowledge ark would have to be resistant to the effects of natural or man-made disasters in order to be viable. Such an ark should include, but would not be limited to, information or material relevant to the survival and prosperity of human civilization. Other types of knowledge arks might include genetic material, such as in a DNA bank.
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The metals of antiquity are the seven metals which humans had identified and found use for in prehistoric times in Africa, Europe and throughout Asia: [1] gold, silver, copper, tin, lead, iron, and mercury. Zinc, arsenic, and antimony were also known during antiquity, but they were not recognised as distinct metals until later.