In astrophysics, the "'Lane Emden equation "'is a dimensionless form of Poisson's equation for the gravitational potential of a Newtonian self-gravitating, spherically symmetric, polytropic fluid.
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If the ideal gas law applies, a process is polytropic if and only if the ratio ( " K " ) of energy transfer as heat to energy transfer as work at each infinitesimal step of the process is kept constant:
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Where e is the specific energy, v is the specific volume, s is the specific entropy, m is the molecular mass, \ gamma here is considered a constant ( polytropic process ), and can be shown to correspond to the heat capacity ratio.
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There are three different classes of PERVs, PERV-A, PERV-B, and PERV-C . PERV-A and PERV-B are polytropic and can infect human cells in vitro, while PERV-C is ecotropic and does not replicate on human cells.
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When the index " n " is between any two of the former values ( 0, 1, " ? ", or " ), it means that the polytropic curve will cut through ( be bounded by ) the curves of the two bounding indices.
