“…The American Society of Lubrication Engineers (ASLE) has compiled 234 apparatus for tribo-testing which are classified by their geometries. Tribometers that have been designed with advanced instrumentation are equipped with instruments that enable the measurement of coefficients of friction, friction forces, wear rates, noise, vibrations, and temperature of a system [218]. Several tribo-testing methods, including four-ball, pin-ondisk, ball-on-disk, ball-on-plate, ball-on-three-plates, and block-on-ring have been primarily used to evaluate the tribological performance of as-prepared water-based lubricants.…”