Calamine brass slowly phased out as zinc smelting techniques were developed in Europe, which produced metallic zinc more suitable for brass production than calamine. However, the conversion away from calamine brass manufacture was slow; a British patent was awarded to William Champion in 1738, but the alloying of metallic zinc and copper to produce brass was not patented until 1781 (by James Emerson), and calamine brass mills persisted in South Wales until as late as 1858. The slow diffusion of this technology was probably the result of economic factors. Calamine brass Calamine brass is brass produced by a particular alloying technique using
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