Measurement of film thickness in lubricated components using ultrasonic reflection.

Many everyday objects are used without consideration of the fact that they rely on a tiny layer of lubricant as thin as 1/1000th of the thickness of a human hair in order to operate correctly. However, without the lubricant, problems are quickly noticed: door hinges squeaking, wear in engines or failure of hip implants. This thesis documents the application of ultrasound to the measurement of this layer of lubricant.