Around casting is 0.1 m in diameter and 0.56 m in length. another casting of the same metal is rectangular in cross section, with a width-to-thickness ratio of 2, and has the same length and cross-sectional area as the round casting. both pieces are cast under the same conditions. what is the difference in the solidification times of the two castings?

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?

Select any two (2) areas of applications of chain-drive. (clo4) a)-permanent lubrication necessary b)-hydraulic forklift truck operation c)-rigging and heavy moving materials d)-relatively high maintenance costs e)-costlier than belt drives

Heat transfer by is the fastest mode of heat transfer that requires no intervening medium. a)-conduction b)-convection c)-radiation d)-conduction and convection