Thermography

The use of infrared thermography whereby temperatures of a wide variety of targets can be measured remotely and without contact. This is accomplished by measuring the infrared energy radiating from the surface of the target and converting this measurement to an equivalent surface temperature.

Thermal conductivity

Measure of the ability of a solid or liquid to transfer heat.

Thermal stability

Ability of a fuel or lubricant to resist oxidation under high temperature operating conditions.

Thin film lubrication

A condition of lubrication in which the film thickness of the lubricant is such that the friction between the surfaces is determined by the properties of the surfaces as well as by the viscosity of the lubricant.

Thixotropy

That property of a lubricating grease which is manifested by a softening in consistency as a result of shearing followed by a hardening in consistency starting immediately after the shearing is stopped.

Three-body abrasion

A particulate wear process by which particles are pressed between two sliding surfaces.

Thrust Bearing

An axial-load bearing.

Timken OK Load

The heaviest load that a test lubricant will sustain without scoring the test block in the Timken Test procedures, ASTM Methods D 2509 (greases) and D 2782 (oils).

Total Acid Number (TAN)

The quantity of base, expressed in milligrams of potassium hydroxide, that is required to neutralize all acidic constituents present in 1 gram of sample. (ASTM Designation D 974.)

Total Base Number (TBN)

The quantity of acid, expressed in terms of the equivalent number of milligrams of potassium hydroxide that is required to neutralize all basic constituents present in 1 gram of sample. (ASTM Designation D 974.)

Tribology

The science and technology of interacting surfaces in relative motion, including the study of lubrication, friction and wear. Tribological wear is wear that occurs as a result of relative motion at the surface.

Turbidity

The degree of opacity of a fluid.

Turbulent flow sampler

A sampler that contains a flow path in which turbulence is induced in the main stream by abruptly changing the direction of the fluid.