Technician A says that to properly lubricate a driveshaft U-joint with twin zerks, grease must be pumped into both nipples. Technician B says that if grease exits all four trunnion seals on a U-joint, it indicates that it has been properly greased and purged. Who is correct?

Estimate the change in specific internal energy au and specific enthalpy h from inlet to outlet for ethylene glycol (a liquid) flowing through each of the following devices: (a) a heat exchanger where the glycol temperature increases from 20 °c to 80 °c; (b) a pump operating at about 25 °c and increasing the glycol pressure from 100 kpa to 8 mpa.