September 2024 | AIChE

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September 2024

Nondestructive testing/examination (NDT/NDE)

Evaluation of an equipment item with the intention of measuring an equipment parameter without damaging or destroying the equipment item.

Nonconductive

Possessing a conductivity of less than 102 pS/m or a resistivity greater than 1010 W-m.

Noncombustible Material

A material that, in the form in which it is used and under the conditions anticipated, will not ignite, support combustion, burn, or release flammable vapors when subjected to fire or heat

Neutral Stability

The ambient boundary layer is well-mixed, with Pasquill stability class D, Ri = 0, and 1/L = 0. Usually occurs with high winds and/or small surface heat fluxes.

Neutral Cloud

The in-cloud density is equal to the ambient density. Neutral cloud and passive cloud are synonymous.

Neutral Buoyant Gas

A gas with density approximately equal to that of air at ambient temperature.

Net Positive Suction Head (NPSH)

The net static liquid head that must be provided on the suction side of the pump to prevent cavitation.

Near-Miss Incident

The description of less severe incidents (i.e., below the threshold for inclusion in a lagging metric), or unsafe conditions that activated one or more layers of protection. Although these events are actual events (i.e., a lagging metric), they are generally considered to be a good indicator of...

Near-Miss

An unplanned sequence of events that could have caused harm or loss if conditions were different or were allowed to progress, but actually did not.

Near-Field

The area within a few hundred meters downwind of the source where there is possible influence of local structures, source geometry, and initial plume momentum and buoyancy effects.

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