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.
The plenum box ensures a continuous flow to the diffuser, and plenum boxes equipped with dampers create the possibility of adjusting the diffuser on an individual level. Further more, the ple-num box is usually supplied with acoustic insulation. This contributes to the sound attenuation inside the box.he plenum boxes are normally delivered with dampers and measuring devices in addition to acoustic insulation. The plenum boxes are equipped with a scaled adjustment wire with a lock-func-tion where the K-factor is independent of the diffuser. The K-factors are printed on the adjustment wire.