Abstract: An electrochemical differential resistance measurement arrangement usable for detecting low concentration ionic impurities such as chemical warfare agents in liquids such as water. The disclosure includes details of electrochemical cells used in the liquid resistance measurement arrangement including one cell with fixed electrode positions and a selective ion transmitting membrane one cell with adjustable electrode position, and a combination cell. A differential bridge electrical circuit, together with a preferred form of alternating current energization therefor, an effluent circuit therefor and a balancing method sequence of steps for the bridge, are also included.

Abstract: A paint or other protective coating removal arrangement involving the use of reciprocal motion ultrasonic frequency mechanical energy applied to the coating by a variety of tool and abrasive substrate members in the company of surface preparation agents such as coolant, heating, softening, and/or abrasive agents. The invention is particularly applicable and disclosed in terms of protective coating removal from aircraft, such as is often necessary for replacement or in the reutilization of aircraft with different identification markings. The coating removal arrangement is environmentally and human operator safe in comparison with presently used coating removal arrangements such as abrasive blasting and chemical solvent removal.