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WÄRTSILÄ
Encyclopedia of Marine and Energy Technology

N

137 results

Non-combustible material

marine

A material which neither burns nor gives off flammable vapours in sufficient quantity for self-ignition when heated to approximately 750°C, this being determined in accordance with the Fire Test Procedures Code, (SOLAS).

Nondestructive test (NDT)

marine

Any test that does not damage the material under test and can, therefore, be used on the finished items.

Nondestructive testing

energy

Nondestructive testing (NDT) is a wide group of analysis techniques used in science and technology industry to evaluate the properties of a material, component or system without causing damage.

Nondestructive testing methods of hull welds

marine

Inspection of welded joints is carried out by non-destructive methods, such as radiography, ultrasonic, magnetic particle or liquid penetrant.

Nonimaging optics

energy

Nonimaging optics is the branch of optics concerned with the optimal transfer of light radiation between a source and a target.

Non-organic grease

marine

A type of grease which does not attack the seal.

Non-return valve

marine

A valve that is designed to prevent a reverse flow. If the valve disc is not attached to the spindle, it is called a screw down non-return (SDNR) valve.

Non-spinning reserve

energy

The non-spinning reserve or supplemental reserve is the extra generating capacity that is not currently connected to the system but can be brought online after a short delay.

Non-volatile petroleum

marine

Petroleum having a flash point of 60°C or above, as determined by the closed cup method of test.

Nordex SE

energy

Nordex SE is a European company that designs, sells and manufactures wind turbines.

Normal conditions (on the bridge), normal sailing conditions

marine

Normal conditions exist when trouble-free operation of the equipment required for thebridge operation is given and environmental conditions with regard to weather and traffic do not cause excessive operator workloads and/or impair visibility.

Normal force

energy

In mechanics, the normal force is the component of a contact force that is perpendicular to the surface that an object contacts.

Normal operational and habitable condition

marine

A condition under which the ship as a whole, the machinery, service, means and aids ensuring propulsion, ability to steer, safe navigation, fire and flooding safety....

Normalising

marine

The type of steel heat treatment. The steel is heated to 850-950°C depending upon its carbon contents and then allowed to cool in air. The resulting product is hard strong steel with a refined grain structure.

Normally unmanned installation

energy

A Normally Unmanned Installation is a type of automated offshore Oil/Gas platform designed to be primarily operated remotely, without the constant presence of personnel.

Not under command (NUC)

marine

A vessel which through exceptional circumstances is unable to manoeuvre as, required by the COLREGs.

Notch ductility

marine

The property of a material whereby it will withstand stress due to a notch or area of stress concentration without cracking or failure.

NOx emissions

marine

see EXHAUST GAS EMISSIONS FROM SHIPS.

NOx REDUCER SYSTEM

marine

The Wärtsilä NOx Reducer System is based on the Selective Catalytic Reduction technique for Nitrogen Oxide (NOx) reduction.

NOx Technical Code

marine

The Technical Code on Control of Emission of Nitrogen Oxides from Marine Diesel Engines adopted by IMO.

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