Ultrasonic monitoring is such a technology.
Most plant systems and equipment generate operational noise of some sort and during failure modes the noise characteristics can change dramatically. Detecting this change and fixing the problem before failure can result in higher quality production output, reduced downtime, reduced maintenance overtime, and greatly reduced costs. In its simplest form, noise is a vibration of molecules through a medium, like air, grease, or metal, which moves spherically outward from its source. Vibrations can be broken down to energy levels at discrete frequencies and when the human ear detects these levels and frequencies, it translates them into intensities and tones which are then transmitted to the brain. The human ear can detect frequencies between 20 Hz and 20 kHz.