Cementation process in the 1740s. In the early modern period, brass, an alloy of copper and zinc, was usually produced by a cementation process in which metallic copper was heated with calamine, a zinc ore, to make calamine brass. Cementation process The cementation process is an obsolete technology for making steel by carburization of iron. Unlike modern steelmaking, it increased the amount of carbon in the iron. It was apparently developed before the 17th century. Derwentcote Steel Furnace, built in 1720, is the earliest surviving example of a cementation furnace. Another example in the UK is the cementation furnace in Doncaster Street,
Average variance extracted Average variance extracted In statistics (classical test theory), average variance extracted (AVE) is a measure of the amount of variance that is captured by a construct in relation to the amount of variance due to measurement error. The average variance extracted was first proposed by Fornell & Larcker (1981). The average variance extracted can be calculated as follows: Here, formula_2 is the number of items, formula_3 the factor loading of item formula_4 and formula_5 the variance of the error of item formula_4. The average variance extracted has often been used to assess discriminant validity based on the following "rule of