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At the transition temperature the tetrahedral framework of beta-quartz twists, resulting in the symmetry of alpha-quartz; atoms move from particular house group positions to more general positions. At temperatures above 867 °C (1,593 °F), beta-quartz changes into tridymite, but the transformation may be very gradual because bond breaking takes place to type a more open construction. At very excessive pressures alpha-quartz transforms into coesite and, at nonetheless higher pressures, stishovite. This Week in History In these videos, find out what happened this week (or any week!) in historical past.

The spray polyurethane foam (SPF) handles the condensation management. Note that in IECC Climate Zones 5 and higher the SPF must be 2 lb/ft3 density. The gypsum board layer need not be installed if the assembly is an attic area somewhat than a cathedral ceiling. However, in such circumstances, an intumescent fireproofing coating utilized to the inside floor of the SPF … Read More