Ammonia enters the expansion valve of a refrigeration system at a pressure of 1.4 mpa and a temperature of 32degreec and exits at 0.08 mpa. if the refrigerant undergoes a throttling process, what is the quality of the refrigerant exiting the expansion valve?

Apipe with an outside diameter of 15 cm is exposed to an ambient air and surrounding temperature of -20°c. the pipe has an outer surface temperature of 65°c and an emissivity of 0.85. if the rate of heat loss from the pipe surface is 0.95 kw per meter of length, the external convective heat transfer coefficient (h) is: (a) 12.5 w/m"k (b) 18.6 w/mk (c) 23.7 w/mk (d) 27.9 w/mk (e) 33.5 w/mk

What is a monomer? how do they form a ploymer from the view point of chemical bonding?

The proportional limit is always greater than the yield strength for a material. a)-trune b)- false