Barcol hardness test the Barcol impressor was developed by Walter Colman as a hand-held, portable means of assessing the hardness of a material during World War II. The United States Army Air Corps required a hand-held method of checking the hardness of rivets due to concerns that aircraft could be sabotaged by replacing normal rivets with soft lead or wooden ones which would fail during flight. The impressor operates when the tip is pressed against the material in question. The hardness of the material determines how far the tip indents and this is transferred by a tension spring and lever to be read
Janka Bryl National Academy of Sciences of Belarus. Bryl's first story appeared in 1938 and his first short story collection appeared in 1946. The first collection of stories was called "Apaviadanni" (Stories). Bryl's books are mostly works of psychological fiction and his characters tend to be sensitive and prone to introspection. They were largely set in Belarusian villages and frequently about the people's fight against the Nazis. Janka Bryl Janka (Yanka) Bryl (, August 4, 1917 – July 25, 2006) was a Belarusian writer best known for his short stories. He was one of the older generation of Soviet writers who had