A source at temperature of $$500K$$ provides $$1000$$ $$kJ$$ of heat. The temperature of environment is $${27^ \circ }C.$$ The maximum useful work (in $$kJ$$) that can be obtained from the heat source is __________

At the inlet of an axial impulse turbine rotor, the blade linear speed is 25 m/s, the magnitude of absolute velocity is 100 m/s and the angle between them is 25°. The relative velocity and the axial component of velocity remain the same between the inlet and outlet of the blades. The blade inlet and outlet velocity triangles are shown in the figure. Assuming no losses, the specific work (in J/kg) is ____________.