The following results were obtained using a Jenike shear cell with time consolidation of 0, 7 and 14 days. Obtain the theoretical minimum opening for a cylindrical silo of hopper half angle 30, H(0) of 2.2 and angle of wall friction of 15. Use a powder bulk density of 1800 kg/m. Assume angle of internal friction is 60 0 day 7 days 14 days fc fc fc 2.6 3.0 5.5 7.0 9.0 10.0 3.1 5.5 5.7 9.0 9.2 12.0 3.4 8.0 5.9 12.0 9.3 14.0 All stress units are kPa. The actual hopper opening is 1 m in diameter; determine the time that the powder can be left in the hopper without arching? 40 #=1111 30 20 f=1.1 ff=1.3 ff=1.4 #f=1.6 ff=1.8 ff=2.0 10 ff=2.5 ff=3.0 0 0 10 20 30 40 50 #f=4.0