Consider the packed bed operating conditions of Problem 5.12, but with Pyrex (p = 2225 kg/m3 ∙ c = 835 J/kg ∙ K. k = 1.4 W/m ∙ K) used instead of aluminum. How long does it take a sphere near the inlet of the system to accumulate 90% of the maximum possible thermal energy? What is the corresponding temperature at the center of the sphere?