A generic data processing engine is operable to receive a format definition and process data formatted according to the definition, without use of formatting information in the data. Depending on the results of the comparison, the assessed impairment rating may be reevaluated, in some cases by a trained impairment evaluator, and others by an expert medical staff. The control unit carries out a judgement that a self-ignition state has been established in the engine depends on one of the rotation speed of the engine and a variation rate of the rotation speed has exceeded a prescribed value. Depending upon the course of instruction, the user could be credited for a partially completed course with fractional credits if so stated in the course description. The glass fragments are thereafter removed from the tumbling apparatus, resulting in smoothed, heat-treated glass fragments that are suitable for direct handling without hand protection. The second sustaining period is included at least at the end of the sustaining period.