Fourcault process the pit must be "heated back" and then the process can continue anew. Glass chemistry has a huge impact on the process since it controls the melting, forming and annealing temperatures, liquidus temperature (point where various chemicals that make up the glass start to crystallize out of the glass) and rates of change of characteristics of the glass itself. Occasionally the ribbon will break or crack, leading to failure of the drawing process. Such breaks, known as "checks" can be alleviated by using proper operating parameters. Sometimes an expedient measure, using a portable source of heat, can be used to
Bioabsorbable metallic glass Bioabsorbable metallic glass Bioresorbable (or bioabsorbable) metallic glass is a type of amorphous metal, which is based on the "Mg-Zn-Ca ternary system". Containing only elements which already exist inside the human body, namely Mg, Zn and Ca, these amorphous alloys are a special type of biodegradable metal. The first reported metallic glass was an alloy (AuSi) produced at Caltech by W. Klement (Jr.), Willens and Duwez in 1960. This and other early glass-forming alloys had to be cooled extremely rapidly (in the order of one mega-kelvin per second, 10 K/s) to avoid crystallization. An important consequence of this was that