Schoch Shift Effect

The Schoch Shift Effect is a very interesting and non intuitive effect. a compression wave who travel in a liquid and strike an elastic solid close to the second critical angle, seems to split in an specular and non specular reflected lobes with the presence of a null zone (as shown bellow).

Schlieren photograph taken by Neubauer and Dragonette:

W. G. Neubauer and L. R. Dragonette, “Measurement of Rayleigh
phase velocity and estimates of shear speed by Schlieren visualization,”
J. Appl. Phys., vol. 45, no. 2, pp. 618–622, 1974.

Lack of Fusion Wagon Tracks

A couple of ¨parallel¨ indications lines bounding  the root bead, are classically called ¨wagon tracks¨ by skilled radiographers.This indication is explained by RT personnel as a couple of almost parallel slag inclusion lines after the root pass has been completed. Sometimes this phenomenon involves a couple of lack of fusion lines side by side as can be seen in the image below:

From one side, the UTPA indication is shown below: