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
Materials Science Laboratory to handle the FIs, the Sample Cartridge Assembly (SCA), together with any associated experiment-dedicated electronics that may be required. A FI is an arrangement of heating elements, isolating zones and cooling zones contained in a thermal insulation assembly. On the outer envelope of this assembly is a water-cooled metal jacket forming the mechanical interface to the Core Facility. The major characteristics of the two produced Furnace Inserts are: The LGF is designed mainly for Bridgman crystal growth of semiconductor materials. It consists of two heated cavities separated by an adiabatic zone. This assembly can establish low and precisely controlled gradients