An experimental study for a tubular centrifuge (R = 30.0 cm ; L = 40 cm; H=10 cm) operating at 1800 rpm processing 100 L/min suggests that the thickness of the cake obeys the following dynamic relationship. e = 4t + 1 where "e" is the thickness of the pie in cm and t is the time in minutes. Experimental data also indicate that the precipitate has SGS = 3.2. Under these conditions, what is the cutting diameter after 1 minute of operation?