code: def gamma_coag(ConcClay, ConcAluminum, coag, material,
                 DiamTube, RatioHeightDiameter):
      
      return (1 - np.exp((
                         (-frac_vol_floc_initial(ConcAluminum, 0*u.kg/u.m**3, coag, material)
                           * material.Diameter)
                          / (frac_vol_floc_initial(0*u.kg/u.m**3, ConcClay, coag, material)
                             * coag.Diameter))
                         * (1 / np.pi)
                         * (ratio_area_clay_total(ConcClay, material,
                                                  DiamTube, RatioHeightDiameter)
                            / ratio_clay_sphere(RatioHeightDiameter))
                         ))
docs: Return the coverage of clay with nanoglobs.
  
      This function accounts for loss to the tube flocculator walls
      and a poisson distribution on the clay given random hits by the
      nanoglobs. The poisson distribution results in the coverage only
      gradually approaching full coverage as coagulant dose increases.
  
      :param ConcClay: Concentration of clay in suspension
      :type ConcClay: float
      :param ConcAluminum: Concentration of aluminum in solution
      :type ConcAluminum: float
      :param coag: Type of coagulant in solution, e.g. floc_model.PACl
      :type coag: floc_model.Material
      :param material: Type of clay in suspension, e.g. floc_model.Clay
      :type material: floc_model.Material
      :param DiamTube: Diameter of flocculator tube (assumes tube flocculator for calculation of reactor surface area)
      :type DiamTube: float
      :param RatioHeightDiameter: Dimensionless ratio of clay height to clay diameter
      :type RatioHeightDiameter: float
  
      :return: Fraction of the clay surface area that is coated with coagulant precipitates
      :rtype: float