Gas tungsten arc welding
Gas tungsten arc welding (GTAW), also known as tungsten inert gas (TIG) welding, is an arc welding process that uses a nonconsumable tungsten electrode to produce the weld . The weld area is protected from atmospheric contamination by a shielding gas (usually an inert more
Ammolite is a rare and valuable opal -like organic gemstone found primarily along the eastern slopes of the Rocky Mountains of the United States and Canada . It is made of the fossil ized shells of ammonite s, which in turn are composed primarily of aragonite , the same mineral that m more
Rudolf 'Rudi' Vrba, born Walter Rosenberg (September 11 , 1924 – March 27 , 2006 ), was a professor of pharmacology at the University of British Columbia . He came to public attention in 1944 when, in April that year, he and a friend, Alfréd Wetzler , became the second and third more
Slate industry in Wales
, Wales, about 1910.
The slate industry in Wales began during the Roman period when slate was used to roof the fort at Segontium , now Caernarfon . The slate industry grew slowly until the early 18th century, then expanded rapidly until the late 19th century, at which t more
Titanium () is a chemical element with the symbol Ti and atomic number 22. It is a light, strong, lustrous, corrosion -resistant (including resistance to sea water and chlorine ) transition metal with a grayish color . Titanium can be alloy ed with other elements such as iron , alumin more