Answer:
Assumption:
1. The kinetic and potential energy changes are negligible
2. The cylinder is well insulated and thus heat transfer is negligible.
3. The thermal energy stored in the cylinder itself is negligible.
4. The process is stated to be reversible
Analysis:
a. This is reversible adiabatic(i.e isentropic) process and thus 
From the refrigerant table A11-A13

sat vapor
m=

b.) We take the content of the cylinder as the sysytem.
This is a closed system since no mass leaves or enters.
Hence, the energy balance for adiabatic closed system can be expressed as:
ΔE
ΔU
)
workdone during the isentropic process
=5.8491(246.82-219.9)
=5.8491(26.91)
=157.3993
=157.4kJ
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Answer:
Civil Engineering.
Explanation:
Civil Engineering is a field of engineering study that deals with professional practising in designing and developing infrastructures such as transport system and networks, buildings, etc.
<u>Civil engineering is regarded as the second--oldest form of engineering studies in the field of engineering.</u>
<u>A person who studies civil engineering is able to design and develop major projects in transportations system such as road construction, bridges, airports, tunnels, etc.</u>
So, Danny, who is interested in studying transporation networks and system should opt for studying civil engineering.