In the case of a refrigeration system undergoing an irreversible cycle, $$\oint {{{SQ} \over T}} $$ is _____________$$\left( { < 0/ = 0/ > 0} \right)$$

One kilomole of an ideal gas is throttled from an initial pressure of $$0.5$$ $$MPa$$ to $$0.1$$ $$MPa.$$ The initial temperature is $$300$$ $$K.$$ The entropy change of the universe is:

A heat reservoir at $$900$$ $$K$$ is brought into contact with the ambient at $$300$$ $$K$$ for a short time. During this period $$9000$$ $$kJ$$ of heat is lost by the heat reservoir. The total loss in availability due to this process is

In adiabatic flow with friction, the stagnation temperature along a streamline ____________ (increase / remains constant)