Liquid water at 100°F and 200 gal/min volumetric flow rate enters a cooling tower operating at steady state. Atmospheric air enters with a dry-bulb temperature of 80°F and a wet-bulb temperature of 60°F. Moist air exits the cooling tower at 90° and 90% relative humidity. Makeup water is provided at 80°F. Calculate the mass flow rates of the dry air and makeup water, each in lb/min, versus return water temperature at 80, 90, and 100°F. Ignore kinetic and potential energy changes.

Coiled springs ought to be very strong and stiff. si3n4 is a strong, stiff material. would you select this material for a spring? explain.

Burgers vector is generally parallel to the dislocation line. a)-true b)-false

To save energy, the air supply to a 2000 ft office has been shut off overnight and the room temperature has dropped to 40°f. in the morning, the thermostat is reset to 70°f and warm air at 120 f begins to flov in at 200ft'/min. the air is well mixed within the room, and an equal mass flow of air at room temperature (changing with time) is withdrawn through a return duct. the air pressure is nearly 1 atm everywhere. ignoring heat transfer with the surroundings and kinetic and potential energy effects, estimate how long it takes for the room temperature to reach 70°f. plot the room temperature as a function of time.