code: def ratio_area_clay_total(ConcClay, material, DiamTube, RatioHeightDiameter):
      
      return (1
              / (1
                 + (2 * material.Diameter
                    / (3 * DiamTube * ratio_clay_sphere(RatioHeightDiameter)
                       * (ConcClay / material.Density)
                       )
                    )
                 )
              )
docs: Return the surface area of clay normalized by total surface area.
  
      Total surface area is a combination of clay and reactor wall
      surface areas. This function is used to estimate how much coagulant
      actually goes to the clay.
  
      :param ConcClay: Concentration of clay in suspension
      :type ConcClay: float
      :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 describing ratio of clay height to clay diameter
      :type RatioHeightDiameter: float
  
      :return: The ratio of clay surface area to total available surface area (accounting for reactor walls)
      :rtype: float