Intech.net - Engineering Glossary, Engineering Dictionary O

O&M - Operations and maintenance

Octane Number - A rating of the 'knock' characteristics of motor fuels.

OEM - Original Equipment Manufacturer.

Off Center - Not centered; offset, eccentric, or inaccurate.

Oil Hardening - A process of hardening a ferrous alloy of suitable composition by heating within or above the transformation
range and quenching in oil.

Oil Mist - A means of lubricating by injecting oil into an air stream producing a finely atomized spray.

Oil Whirl/Whip - An unstable free vibration whereby a fluid-film bearing has insufficient unit loading.

Oilstones - Moulded abrasives in various shapes used to hand-sharpen cutting tools.

OLED - Organic Light-Emitting Diode

Olefin - Aliphatic hydrocarbons with one or more double bonds along the chain.

Organic compound - Any compound containing carbon except for the carbonates (carbon dioxide, the carbonates and
bicarbonates), the cyanides, and cyanates.

Original Equipment Manufacturer - Products supplied by the company which first created the product.

Otto Cycle - An idealized reversible cycle of four operations occurring in a perfect four-stroke petrol engine.

Ounce Force - A derived unit of force in the British system of units.

Outer Dead Centre - Also known as bottom dead centre.

Outside Caliper - An instrument used to measure the outer dimension of an object.

Overrun - Often used to describe the condition where rotating machinery is in a coast down condition.

Oxidizing Flame - An oxyacetylene flame in which there is an excess of oxygen.

Oxyacetylene Welding - A welding process in which the required temperature is attained by flames obtained from the
combustion of acetylene with oxygen.

Oxygen Cutting - A process of cutting ferrous metals by means of the chemical action of oxygen on elements in the base
metal at elevated temperatures.