Consider a fluid with mean inlet temperature ti flowing through a tube of diameter d and length l, at a mass flow rate . the tube is subjected to a surface heat flux that can be expressed as , where a and b are constants. determine an expression for the mean temperature of the fluid as a function of the x-coordinate.

In a unit cell of fcc structure, indicate the position of one of the tetrahedral interstitial sites by plotting the corresponding tetrahedron. do the same for one of the octahedral interstitial sites (in a separate fcc unit cell). mark the positions of all the tetrahedral and octahedral interstitial sites in the unit cells. how many equivalent tetrahedral sites and how many equivalent octahedral sites are contained in a fcc unit cell, respectively. what is the coordination number for a tetrahedral site and what is the coordination number for an octahedral site?