Determine whether or not each of the following four transaction execution histories is serializable. If a history is serializable, specify a serial order of transaction execution to which it is equivalent

A. r1[x] r2[y] w2[x] r1[z] r3[z] w3[z] w1[z]
B. w1[x] w1[y] r2[u] w2[x] r2[y] w2[y] w1[z]
C. w1[x] w2[y] r2[u] w1[z] w2[x] r2[y] w1[u]
D. w1[x] w2[u] w2[y] w1[y] w3[x] w3[u] w1[z]

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.

Acompressor receives the shaft work to decrease the pressure of the fluid. a)- true b)- false

An ideal otto cycle with air as the working fluid has a compression ratio of 8. the minimum and maximum temperatures in the cycle are 300 k and 1340 k. use constant specific heats at room temperature to determine (a) the amount of heat transferred to the air during the heat- addition kj/kg, (b) the thermal efficiency, and (c) the thermal efficiency of a carnot cycle ope limits. process, in rating between the same temperature