Determine the carburizing time $($in s$)$ necessary to achieve a carbon concentration of $0\mathrm{.}44wt\%$ at a position $1\mathrm{.}4$ mm into an iron$-$

carbon alloy that initially contains $0\mathrm{.}031wt\%C.$ The surface concentration is to be maintained at $1\mathrm{.}2wt\%C,$ and the treatment is to be

conducted at $1110C.$ Assume that $D_0=5\mathrm{.}1{10}^{-5}\frac{m^2}{s}$ and $Q_d=154k\frac{J}{m}ol.$ You will find the table below useful.