$9.$ True$/$False: Trickle bed reactors are advantageous due to their high energy consumption compared to other reactor types.

$10.$ True$/$False: Flow regime identification is not critical when designing multiphase flow systems.

$11.$ True$/$False: Optical imaging cannot be used to estimate volume fractions in multiphase flows.

$12.$ True$/$False: The drift velocity in the drift flux model represents the velocity of the liquid phase relative to the pipe walls.