The American black bear lived during the same period as short-faced bears (Arctodus simus and A. pristinus) and the Florida spectacled bear (Tremarctos floridanus). These Tremarctine bears evolved from bears that had emigrated from Asia to North America 7â8 ma.
A plenum space is a part of a building that can facilitate air circulation for heating and air conditioning systems, by providing pathways for either heated/conditioned or return airflows, usually at greater than atmospheric pressure.
plenum chamber. A component of a jet engine designed to hold air at a pressure slightly higher than that of the surrounding air. Plenum chambers stabilize the pressure of the air before it enters the compressor.n enclosed space in which a plenum condition exists; air is forced into it for slow distribution through ducts.