“…In general, combining NDT methods with root cause analysis can be a very useful procedure also in other industrial areas, including mechanics [10,11], hydraulics of working machines [12], heat flows [13], as well as diagnostics of modified surfaces [14,15], including plasma-sprayed coatings [16] or electro-spark deposition ESD combined with laser machining [17,18]. This approach may also be useful in the biotechnology industry [19,20], where the cause-effect relationships of the processes are very complicated due to numerous feedbacks and the occurring circular processes.…”