The tensile and shear strength of a composite are known to be F1t = 400MPa, F2t = 50MPa, F6 = 80MPa, and its compressive strength in both directions are twice stronger. Its elastic moduli are E11 = 50GPa, E22 = 10GPa, G12 = 8GPa, ν12 = 0.5. Two types of loading are to be applied to the compo i) σ11 and σ22; ii) σ11 and σ12. Based on the maximum stress and the maximum strain theories, plot the failure surface to indicate the boundary of safe and unsafe regions in the two-dimensional stress space for each of the two loading conditions.

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?

A2-m rigid tank initially contains saturated water vapor at 100 kpa. the tank is connected to a supply line through a valve. steam is flowing in the supply line at 600 kpa and 300 c. the valve is opened, and steam is allowed to enter the tank until the pressure in the tank reaches the line pressure, at which point the valve is closed. a thermometer placed in the tank indicates that the temperature at the final state is 200°c. determine (a) the mass of steam that has entered the tank (b) the amount of heat transfer.

What is the major difference between thermoplastics and thermosetting plastics from the polymerization structure point of view?