“…The dual-phase-lag heat shown in Equation ( 5 ) has been applied in mathematical modeling of the heat transfer in functionally graded materials [ 13 , 14 , 15 ], ultrafast pulse-laser heating problems [ 16 , 17 ], porous media [ 18 , 19 , 20 ], nanocomposites [ 21 , 22 ], and living tissue [ 23 , 24 , 25 ]. If in Equation ( 5 ), then the classical parabolic heat conduction equation is obtained.…”