1. It can also be expanded to include irreversible polytropic processes. 2. One common class of barotropic model used in astrophysics is a polytropic fluid. 3. The constant is known as the polytropic index. 4. The index n is the polytropic index that appears in the polytropic equation of state, 5. The index n is the polytropic index that appears in the polytropic equation of state, 6. Axial compressors can have high efficiencies; around 90 % polytropic at their design conditions. 7. The polytropic process equation can describe multiple expansion and compression processes which include heat transfer. 8. The polytropic exponent ( n + 1 ) / n } } is sometimes preferred over. 9. This exponent is a polytropic value for the ratio of variable heats for air and similar gases at the temperatures present. 10. Sometimes the word " polytrope " may be used to refer to an equation of state that looks similar to the polytropic fluid.