Our rotameter has been calibrated for nitrogen at room temperature and atmospheric pressure; the calibration shows that for a reading (float-position) of 50% of the height of the rotameter tube the volumetric flow rate is 100 cm3/min. we now need to measure the flow of helium at room temperature and atmospheric pressure, using the same rotameter. when the reading is 50% of full scale, estimate the helium volumetric flow rate. for this problem you can consider that the density of float () is much higher than that of the fluid ( ).

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?