.ClaRa.SubSystems.Furnace.FreeboardSlice_L4.ParticleMigration .ClaRa.SubSystems.Furnace.FreeboardSlice_L4.ParticleMigrationmodel ParticleMigration = ClaRa.Components.Furnace.GeneralTransportPhenomena.ParticleMigration.FixedMigrationSpeed_simple(w_fixed = 1);