3. A 1000-g sample from the stockpile of the same aggregate as in Problem 2 weighed 635 g when immersed in water. Calculate the moisture content of the aggregate in the stockpile?

Apreheater involves the use of condensing steam at 100°c on the inside of a bank of tubes to heat air that enters at 1 atm and 25°c. the air moves at 5 m/s in cross flow over the tubes. each tube is 1 m long and has an outside diameter of 10 mm. what is the minimum value of nl needed to achieve an outlet temperature of t 75 c? what is the corresponding pressure drop across the tube bank?