Amass of m = 1 kg of an ideal gas (gas constant r= 278 j/kgk) undergoes two polytropic processes. during the first process temperature increases from 27 0c to 237 0c and volume decreases from 1 m3 to 0.3 m3. during the second process temperature increases to 473 0c and volume is constant. the isentropic exponent of the gas is 1.4. determine (a) polytropic exponents (b) missing properties of the gas (c) heat and work of the first process and (d) draw the processes in p-v diagram

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?

Different types of steels contain different elements that alter the characteristics of the steel. for each of the following elements, explain what the element does when alloyed with steel.

Which of the following refers to refers to how well the control system responds to sudden changes in the system. a)-transient regulation b)- distributed regulation c)-constant regulation d)-steady-state regulation