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+clear;
+clc;
+disp('Example 15.4');
+
+// aim : To determine
+// (a) the pressure, volume and temperature at cycle state points
+// (b) the heat received
+// (c) the work done 
+// (d) the thermal efficiency
+// (e) the carnot efficiency
+// (f) the work ration
+// (g) the mean effective pressure
+
+// given values
+ro = 8;// overall volume ratio;
+rv = 6;// volume ratio of adiabatic compression
+P1 = 100;// initial pressure , [kN/m^2]
+V1 = .084;// initial volume, [m^3]
+T1 = 273+28;// initial temperature, [K]
+Gama = 1.4;// heat capacity ratio
+cp = 1.006;// specific heat capacity, [kJ/kg K]
+
+// solution
+// taking reference  Fig. 15.18
+// (a)
+V2 = V1/rv;// volume at stage2, [m^3] 
+V4 = ro*V2;// volume at stage 4;[m^3]
+// using PV^(Gama)=constant for process 1-2
+P2 = P1*(V1/V2)^(Gama);// pressure at stage2,. [kN/m^2]
+T2 = T1*(V1/V2)^(Gama-1);// [K]
+
+P3 = P2;// pressure at stage 3, [kN/m^2]
+V3 = V4/rv;// volume at stage 3, [m^3]
+// since pressure is constant in process 2-3 , so using V/T=constant, so
+T3 = T2*(V3/V2);// temperature at stage 3, [K]
+
+// for process 1-4
+T4 = T1*(V4/V1);// temperature at stage4, [K
+P4 = P1;// pressure at stage4, [kN/m^2]
+
+mprintf('\n (a)  P1  =  %f kN/m^2,    V1  =  %f m^3,       t1  =  %f C,\n      P2  =    %f kN/m^2,    V2  =  %f m^3,      t2  =  %f C,\n      P3  =  %f kN/m^2,    V3  =  %f m^3,       t3  =  %f C,\n      P4  =  %f kN/m^2,      V4  =  %f m^3,       t4  =  %f C\n',P1,V1,T1-273,P2,V2,T2-273,P3,V3,T3-273,P4,V4,T4-273);
+
+// (b)
+R = cp*(Gama-1)/Gama;// gas constant, [kJ/kg K]
+m = P1*V1/(R*T1);// mass of gas, [kg]
+Q = m*cp*(T3-T2);// heat received, [kJ]
+mprintf('\n (b) The heat received is  =  %f kJ\n',Q);
+
+// (c) 
+W = P2*(V3-V2)-P1*(V4-V1)+((P3*V3-P4*V4)-(P2*V2-P1*V1))/(Gama-1);// work done, [kJ]
+mprintf('\n (c) The work done is  =  %f  kJ\n',W);
+
+//  (d)
+TE = 1-T1/T2;// thermal efficiency
+mprintf('\n (d) The thermal efficiency is  =  %f  percent\n',TE*100);
+
+// (e)
+CE = (T3-T1)/T3;// carnot efficiency
+mprintf('\n (e) The carnot efficiency is  =  %f  percent\n',CE*100);
+
+// (f)
+PW = P2*(V3-V2)+(P3*V3-P4*V4)/(Gama-1);// positive work done, [kj]
+WR = W/PW;//  work ratio
+mprintf('\n (f) The work ratio is  =  %f\n',WR);
+
+// (g)
+Pm = W/(V4-V2);// mean effective pressure, [kN/m^2]
+mprintf('\n (g) The mean effective pressure is  =  %f  kN/m^2\n',Pm);
+
+//  there is minor variation in answer reported in the book
+
+//  End