SPEKTRA Volume 3 issue 3 contains 6 papers: 1) Two-Dimensional Dynamics Of Spherical Grain Floating On The Propagating Wave Fluid Surface, 2) Struktur Mikro Dan Sifat Magnetik Dari Lapisan Tipis Nanokomposit Fe3o4/Pvdf, 3) Pengaruh Gelombang Mikro (Microwave Assisted) Terhadap Kurva Histerisis Dari Bahan Ferromagnetik Copd Berbentuk Ellipsoid, 4) Identifikasi Ketebalan Lapisan Sedimen Dan Struktur Bawah Permukaan Di Zona Amblesan Kota Lama Semarang Berdasarkan Data Mikroseismik, 5) Synthesis Of Sodalite Zeolite From Coal Bottom Ash With Variation Of Naalo2 Concentration Using Alkali Melting Hydrothermal Method, 6) The Effect Of Synthetic Zeolites On Sensitivity And Stability Of Uric Acid Biosensor Using Cycle Voltametry Method.