**a. The thermodynamic cycle**

It is a "standard" Brayton cycle, usually adopted in large scale turbogas. With the exception of the industrial cycles, for constructive reasons, the compression ratio is extremely low in this UMGT (p2/p1 ≈ 2), and therefore the total efficiency of the machine is corresponding low (7-8%). Increase of the compression ratio, recovery of the heat of the gas are possible modifications under investigation, to increase such efficiency: but such upgrading appear difficult to implement on an UMGT device.
