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.
It ensures, through the use of baffles, that air pressure is equalised for the purpose of even air distribution. In terms of an outdoor digital signage enclosure, a plenum chamber ensures both the even distribution of air and resistance to water ingress during pressurised wash down.This is achieved through the optimal placement of baffles within the plenum.An Armagard Plenum Chamber.t ensures, through the use of baffles, that air pressure is equalised for the purpose of even air distribution. In terms of an outdoor digital signage enclosure, a plenum chamber ensures both the even distribution of air and resistance to water ingress during pressurised wash down.