Gas bubble detection in liquid metals by means of the ultrasound transit-time-technique Artur Andruszkiewicz, Kerstin Eckert, Sven Eckert and Stefan Odenbach Eur. Phys. J. Special Topics, 220 (2013) 53-62 Published online: 26 March 2013 DOI: 10.1140/epjst/e2013-01796-0