Problem 4. (30 points) For the outlet temperature control system of steam-heated stirred tank shown as in the figure below, (a) (10 points) Specify whether the control valve is air-to-close or air-to-open; (b) (10 points) Should the temperature controller, TC, be reverse acting or direct acting? Justify your answer. Assume that I/P transducer has negligible dynamics and positive gain; (C) (10 points) Propose a feedback/feedforward control method and draw the control diagram. You could add controllers, transducers or other instruments if needed. Please also include transmission lines between various instruments. Note that thermocouple measures the temperature of liquid in the tank, which is same as outlet temperature. Transmitter TT CM Controller TC Current-to-pressure (VP) transducer Thermocouple + Ps C Steam Condensate