The emissivity of galvanized steel sheet, a common roofing material, is 0.13 at temperatures around 300 K, while its absorptivity for solar irradiation is 0.65. Determine the surface temperature, in °C, of a roof constructed of the material on a day when 350 W/m2, [infinity] 16°C, and 7 W/m2·K. Assume the bottom surface of the steel is insulated.

Amass of m 1.5 kg of steam is contained in a closed rigid container. initially the pressure and temperature of the steam are: p 1.5 mpa and t 240°c (superheated state), respectively. then the temperature drops to t2= 100°c as the result of heat transfer to the surroundings. determine: a) quality of the steam at the end of the process, b) heat transfer with the surroundings. for: p1.5 mpa and t 240°c: enthalpy of superheated vapour is 2900 kj/kg, specific volume of superheated vapour is 0. 1483 m/kg, while for t 100°c: enthalpy of saturated liquid water is 419kj/kg, specific volume of saturated liquid water is 0.001043m/kg, enthalpy of saturated vapour is 2676 kj/kg, specific volume of saturated vapour is 1.672 m/kg and pressure is 0.1 mpa.

Draw the engineering stress-strain curve for (a) bcc; (b) fcc metals and mark important points.

A)-explain briefly the importance of standards in engineering design. b)- what is patent? c)-explain the relationship between these standards: b. s. and b. s.en d)- in engineering design concepts, types of loads and how they act are important factors. explain.