It is known that after the concrete is adjusted by trial mixing, the amount of various materials is: cement 3.10kg, water 1.86kg, sand 6.24kg, crushed stone 12.8kg, and the apparent density of the mixture is 2500kg ∕ m3 . : (1)How much is the amount of per cube concrete material? (2)If the moisture content of sand at the construction site is 2.5%, and the moisture content of stone is 0.5%, find the construction mix ratio.

Air inially occupying a volume of 1 m2 at 100 kpa, 27 c undergoes three internally reversible processes in series. process 1-2 compression to 500 kpa during which pv constant process 2-3 adiabatic expanslon to 100 kpa process 3-1: constant-pressure expansion to 100 kpa (a) calculate the change of entropy for each of the three processes. (b) calculate the heat and work involved in each process. (c) is this cycle a power cycle or refrigeration cycle?