The company PureNSafe is designing a portable, solar-powered disinfection system for Army use only. The system is simply an inlet pipe, a pump, a mixing chamber and an outlet pipe. The water is continuously pumped into the chamber where it is irradiated with UV light before it exits through the the appropriate tube into a collection vessel. The disinfection rate constant rate of disinfection with UV light is 7.80 s.1 and the amount of bacteria has to be reduced by 99.9%. be reduced by 99.9%. Since the Army requires an object that can be carried in a backpack, it requires that the chamber of the apparatus must not hold a capacity greater than 2 L. How much water will the system be able to produce during 10 hours of sunshine?

Acommercial grade cubical freezer, 4 m on a side, has a composite wall consisting of an exterior sheet of 5.0-mm thick plain carbon steel (kst= 60.5 w/m k), an intermediate layer of 100-mm thick polyurethane insulation (kins 0.02 w/m k), and an inner sheet of 5.0- mm thick aluminium alloy (kal polyurethane insulation and both metallic sheets are each characterized by a thermal contact resistance of r 2.5 x 104 m2 k/w. (a) what is the steady-state cooling load that must be maintained by the refrigerator under conditions for which the outer and inner surface temperatures are 25°c and -5°c, respectively? (b) for power saving purpose, which wall material should be increased/reduced in. thickness in order to reduce 50% of the cooling load found in part (a)? redesign the thickness of the proposed material. 177 w/m-k). adhesive interfaces between the q=575.93 w