A series of long stainless steel bolts (ASTM A437 B4B) are fastened into a
metal plate with a thickness of \(4 \mathrm{~cm}\). The bolts have a thermal
conductivity of \(23.9 \mathrm{~W} / \mathrm{m} \cdot \mathrm{K}\), a specific
heat of \(460 \mathrm{~J} / \mathrm{kg} \cdot \mathrm{K}\), and a density of
\(7.8 \mathrm{~g} / \mathrm{cm}^{3}\). For the metal plate, the specific heat,
thermal conductivity, and density are $500 \mathrm{~J} / \mathrm{kg} \cdot
\mathrm{K}, 16.3 \mathrm{~W} / \mathrm{m} \cdot \mathrm{K}\(, and \)8
\mathrm{~g} / \mathrm{cm}^{3}$, respectively. The upper surface of the plate
is occasionally exposed to cryogenic fluid at \(-70^{\circ} \mathrm{C}\) with a
convection heat transfer coefficient of $300 \mathrm{~W} / \mathrm{m}^{2}
\cdot \mathrm{K}$. The lower surface of the plate is exposed to convection
with air at \(10^{\circ} \mathrm{C}\) and a convection heat transfer coefficient
of \(10 \mathrm{~W} / \mathrm{m}^{2}\). K. The bolts are fastened into the metal
plate from the bottom surface, and the distance measured from the plate's
upper surface to the bolt tips is \(1 \mathrm{~cm}\). The ASME Code for Process
Piping limits the minimum suitable temperature for ASTM A437 B4B stainless
steel bolt to \(-30^{\circ} \mathrm{C}\) (ASME B31.3-2014, Table A-2M). If the
initial temperature of the plate is \(10^{\circ} \mathrm{C}\) and the plate's
upper surface is exposed to the cryogenic fluid for \(9 \mathrm{~min}\), would
the bolts fastened in the plate still comply with the ASME code? Using the
explicit finite difference formulations with a uniform nodal spacing of
\(\Delta x=1 \mathrm{~cm}\), determine the temperature at each node for the
duration of the upper surface being exposed to the cryogenic fluid. Plot the
nodal temperatures as a function of time.