Table 5.

Summary of the experimental observations.

	EMATs	MSTs
Advantages	- Low sensitivity to surface debris and surface roughness	- High amplitude and SNR of SH wave signal
Disadvantages	- Low amplitude and SNR of SH wave signal - Requirement to maintain a uniform lift off to provide consistent transduction	- Requirement of a relatively large normal force to excite and receive SH waves through dry fractional coupling - SH wave amplitude dependence on the normal force value and the degree of surface roughness - Limited operation on the surface where friction-reducing debris are present