code: def jenkins_rao(target, throat_perimeter='throat.perimeter',
                  throat_area='throat.area',
                  throat_diameter='throat.indiameter'):
      r
      P = target[throat_perimeter]
      A = target[throat_area]
      r = target[throat_diameter]/2
      # Normalized by value for perfect circle
      value = (P/A)/(2/r)
      return value
docs: r"""
      Jenkins and Rao relate the capillary pressure in an eliptical throat to
      the aspect ratio
  
      References
      ----------
      Jenkins, R.G. and Rao, M.B., The effect of elliptical pores on
      mercury porosimetry results. Powder technology, 38(2), pp.177-180. (1984)