TY - RPRT TI - Report no. 22- thread crack detection on railroad wheels : an ultrasonic system using EMATS AU - Schramm, Raymond E AU - Clark, Alfred V AU - Mitrakovic, Dragan V AU - Cohen, Yossef AU - Schull, Peter J AU - Schaps, Stephen R PY - 1991 PB - National Institute of Standards and Technology CY - Gaithersburg, MD SN - NIST IR 3967 DO - 10.6028/NIST.IR.3967 ER -