On the structurization of coal dust precipitations and their influence   on aerodynamic resistance by granulated mediums in air filters at nuclear   power plants
  The processes of structurization of dust precipitations in granulated filtering mediums, formed by the monolithic glass spherical granules with the diameters of 2mm and 3mm, are re-searched. The distinctions between the distributions of filtered coal dust masses in the air filters with cylindrical granules and the air filters with spherical granules, are found. The influences by the filtered dust masses on the air resistance of both the air filters with the cylindrical granules and the air filters with the spherical granules are described. The conclusions on a possibility of the use of various chemical adsorbents with different geometric forms and volumetric dimensions to improve the filtering properties of granulated filtering mediums in air filters at nuclear power plants are formulated. 
I. M. Neklyudov, O. P. Ledenyov, L. I. Fedorova, P. Ya. Poltinin
physics.ao-ph cond-mat.soft