Aspring-loaded piston - cylinder device is initially filled with 0.15 lbm of an r-134a liquid-vapor mixture whose temperature is -20°f and whose quality is 75 percent. the spring constant in the spring force relation f = kx° is 40 lbf /in, and the piston diameter is 12 in. the r-134a undergoes a process that increases its volume by 50 percent. calculate the final temperature and enthalpy of the r-134a