Description: Length of time that maintenance is performed on an object, including technical, logistical, and internal administrative delays; Name: time for maintenance 
Description: Time interval when maintenance is carried out on an item including technical, logistic and internal administrative delays; Name: Maintenance time
Description: through a surface, product of the sound pressure, p, and the component of the particle velocity, un, at a point on the surface in the direction normal to the surface, integrated over that surface; Name: sound power