A circulation type media agitator mill includes a cylindrical vessel, and an agitating member arranged rotatably in the cylindrical vessel. By using Matched Replica correlation processing with the local and reference signals subdivided into discrete segments prior to correlation, the effects of mobile clock drift and Doppler shifts can be mitigated allowing for increased processing gain. A coating is applied to the sheet and the light detector, wherein penetration of the coating by a light source allows the light source to scatter within the sheet. Multiple elastic straps 500 can be connected end-to-end forming an elongated elastic strap of desired length having closed central hooks with open hooks on each end. In other embodiments, the key is merely a web address that the user may contact. The magnitude of the conductor current necessary for this compensation is a measure for the amount of nano-particles present at the sensor.