Uniform zakuthupi khalidwe, wandiweyani lamellar kapangidwe, pamwamba lathyathyathya ndi yosalala, si kosavuta mapindikidwe, ntchito khola, ndi
m'mphepete kuwala ndi yosalala, kosavuta kugwa m'mphepete ndi wosanjikiza, zoipa, sanali kuwala ndi mpweya permeability.