If
ø is temperature in a canned food at time t,
øo is initial temperature of a canned food,
øc is a retort temperature on an assumption of a constant,
K is a thermal diffusivity, u=θ-θe, uo=θ0-θe,
u=0 under the boundary condition of a ?? square can
(length=a, width=b, height=c)
and the initial condition being u=uo (constant),
then u may be represented with a formula (10), except earlier time of the process.
Therefore, a temperature of the center of the can may be indicated with a formula (11).
The calculations of the writer's formula (11) are tested for the date formerly reported as to the square sized cans of sardine in oil by Itani and Ito (1915) and Lang (1935) respectively.
The results are shown in the Tables I, II, III and V.
It can be concluded from the Lang's data, that ƒn for the 1/2 sardine in oil should be 13.5 rather than 22.2 of his description. (See Fig. 2)
