 heat conduct ga inert intern model heat conduct ga inert intern model rate energi transfer parallel flat plate evalu stagnant ga polyatom inert intern mode deviat thermal conduct complet equilibrium inert mode relax time effect wall excit de-excit mode linear theori consist small temperatur differ plate eucken-valu conduct exceed relax time non-zero plate effect excit inert mode relax time short wall energi transfer rate small wall presenc felt distort temperatur profil boundari layer adjac wall order thick time result analog hirschfeld's 1956 case chemic reaction experiment measur conduct hot wire cell type apparatu extrapol measur reciproc conduct reciproc pressur load full eucken slope reciproc appar measur conduct versu reciproc pressur curv function relax time well accommod coeffici relax compar temperatur jump effect rotat diatom molecul 