Sound waves are transmitted into the test part. Reflections of these waves are monitored and evaluated for acceptance. Fluorescent and visible dyes are applied to the test objects. These dyes will highlight indications open to the material surface. An eddy current field is established in a test part. As this part moves past a coil arrangement discontinuities in the field are measured and compared against known standards.   Magnetic fields are induced into the test object. Metallic powders (wet or dry) are applied to the surface and reveal surface and near surface interruptions in the magnetic field. Infra-red thermography produces digital images which detect changes in heat emmitted by an object. Analysis of this image can detect mechanical friction in maintenance applications, electrical problems, discontinuities in materials and assist in a variety of troubleshooting.