Heat sterilization of lumber, timbers, and pallets is used to kill insects to prevent their transfer between countries in international trade. This is analogous to food sterilization by heat. A...

Question7: Calculate the ratio of the two heating times (for a single board versus when
they are stacked), and explain the ratio.


Note1: Don’t use Heissler charts to answer this question.
Note2: You’re free to make assumptions regarding any value you think you need in order to solve the problem. Just explain your reasoning behind your assumption in a logical manner.

please explain step by step for better understanding, thanks

Extracted text: Heat sterilization of lumber, timbers, and pallets is used to kill insects to prevent their transfer between countries in international trade. This is analogous to food sterilization by heat. A typical requirement here is that the slowest heating point of any wood configuration be held at 56 °C for 30 minutes. Consider hot air heating of wooden boards that maintains their surface temperature at 70 °C. The boards are stacked outside and in the winter time they can be considered to be at 0 °C when they are brought in for heating. The thermal diffusivity of the wood is 9*10-8 m?/s.