The firing shrinkage of a clay is usually about the same as the drying shrinkage. Total shrinkage will usually be about 8-12%. The next stage that happens during the firing process is vitrification. This is the hardening, tightening and finally the partial glassification of the clay. Vitrification results from fusions or melting of the various components of the clay.
Middlesboro is served by the Middlesboro-Bell County Airport, which is a single runway, general aviation airport and is the second oldest airport still in use in Kentucky, ranking behind Bowman Field in Louisville.. The airport was established in 1944, however, the first recorded flight into the city was in 1912.
Murfreesboro is a city in and the county seat of Rutherford County, Tennessee, United States. The population was 108,755 according to the United States Census Bureau's 2010 U.S. Census, up from 68,816 residents certified during the 2000 census. The center of population of Tennessee is located in Murfreesboro. The city is part of the Nashville metropolitan area, which includes thirteen counties and a population of 1,666,566 (2009).