In the above article,1p(1γ)/γ in Eq. (29) should be replaced by p(γ1)/γ, so this equation should read

(1)

This was an isolated misprint, and the subsequent formulas were not affected in any way.

The author is grateful to Miguel Barros for pointing out this error.

1.
J. P. S.
Bizarro
, “
The thermodynamic efficiency of heat engines with friction
,”
Am. J. Phys.
80
,
298
305
(
2012
).