In a constant-head permeability test, the length of the specimen is 200 mm and the cross sectional area is 78.5 cm2. If k = 2.1 x 10^-2 cm/sec, and a rate of flow of 130 cm3/min has to be maintained during the test, what should be the head difference across the specimen?

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?