1. THE HYDRODYNAMIC OF THREE-PHASE FLUIDIZED BED WITH LOW DENSITY SOLIDS. Authors: POP ALEXANDRU, DRAGAN S., BOTAR-JID C..2. MATHEMATICAL MODELING FOR THE CRYSTALLIZATION PROCESS OF HYDROXYAPATITE OBTAINED BY PRECIPITATION IN AQUEOUS SOLUTION. Authors: VALENTINA R. DEJEU, BARABÁS RÉKA, POP ALEXANDRU, BOGYA ERZSÉBET SÁRA, PAUL ŞERBAN AGACHI.