Tin pest related problems such as tin whiskers. At 13.2 °C (about 56 °F) and below, pure tin transforms from the silvery, ductile metallic allotrope of β-form "white tin" to the brittle, nonmetallic, α-form "grey tin" with a diamond cubic structure. The transformation is slow to initiate due to a high activation energy but the presence of germanium (or crystal structures of similar form and size) or very low temperatures of roughly −30 °C aids the initiation. There is also a large volume increase of about 27% associated with the phase change to the nonmetallic low temperature allotrope. This frequently makes tin
EMLL 15th Anniversary Show EMLL 15th Anniversary Show Mexican professional wrestling promotion Empresa Mexicana de Lucha Libre (EMLL) commemorated their 15th anniversary with two "'EMLL 15th Anniversary Shows". The first Anniversary show was held on September 22, 1948 in Arena Coliseo in Mexico City, Mexico, EMLL's main venue. The second event took place two days later on September 24, 1948 in Arena Modelo. The events commemorated the 15th anniversary of EMLL, which would later become the oldest professional wrestling promotion in the world. The Anniversary show is EMLL's biggest show of the year, their Super Bowl event. The first anniversary show featured the EMLL