16. A cylindrical reactor fitted with Rushton Turbine has a liquid volume of 100,000 litres. It has an aspect ratio (the ratio of the channel height to the width) of 2:1. The diameter of the impeller should be approximate:

A. 1.3 m
B. 3.3 m
C. 5.3 m
D. 7.3 m

17. In the bubble boundary layer, oxygen concentration can be determined by measuring

A. the steady-state oxygen concentration in a mixed aerated reactor before inoculation
B. the steady-state oxygen concentration in a mixed aerated reactor after inoculation
C. the steady-state oxygen concentration in the boundary layer using a micro-probe
D. volume of oxygen supplied

18. Impeller damage can be minimized by

A. using specially designed axial flow impellers
B. using radial flow impellers
C. using Intermig impellers
D. all of the above

19. To increase the oxygen transfer rate in a shake flask culture system, which of the following (s) is/are followed?

A. Liquid volume in the flask is reduced
B. Stirrer speed is increased
C. Baffled flasks are used
D. All of the above

20. What is/are the major difference(s) between disc and turbine type stirrer?

A. Blades in disc type are projected out beyond the edge of the disc while blades are curved one in turbine type
B. Turbine type requires 50 % less air than disc type for the same yield and energy consumption
C. Both (a) and (b)
D. Number of blades in the stirrer