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 Kulcsár the next year, she won a prize in the National Chamber Music Competition. Kulcsár works mainly with singers. She accompanied Marianna Sipos in the ARD International Music Competition in 2012. Founding member of the Moltopera Company since 2011. She accompanied among others Moltopera's production Don Giovanni, Magic Flute (in the Palace of Arts), Fledermaus, La Bohéme, Cavalleria Rusticana, Menotti's: The telephone, L'enfant et les sortiléges (in the National Theater of Pécs), and "How to survive an opera recital?" (in the Sziget Festival). Janka Kulcsár Janka Kulcsár (born 8 April 1985) is a Hungarian pianist and répétiteur, and a founding member