Non-Destructive Evaluation: Science and Technology

I shall make a review of the status of "Non-destructive evaluation (NDE) : Science and Technology". I am aware that this is a very mixed audience. There are the techn-icians and scientists of the laboratory; we have also members of the public, students and the media; so I would spend a few minutes explaining for the benefit of the uninitiated as to what non-destructive techniques are. The best way to carry the point home to all of you is to talk about the application of these techniques in medicine and physiology. I am sure all of you know about X-rays or most of you have been X-rayed sometime or the other when it was suspected that your human skeleton structure, bone structure, has undergone fracture due to an accident. Bones are opaque to x-rays, and if there is a fracture you are able to identify this in a two-dimensionalpicture, in a film or in a screen. There are similar other techniques. When we do computer aided scanning using X-rays, we use principles of mathematics to re-construct a three dime-nsional picture of the object that is being scanned; this is the technique of CATSCAN or computer aided tomograph