SPEKTRA Volume 4 issue 1 contains 5 papers: 1) Proton Dripline for Isotone N = 18, 20, and 22 Using Modified Relativistic Mean Field (MRMF) Model; 2) The Effect of Poly (Ethylene Glycol) on The Photoluminescence Properties of Carbon Dots from Cassava Peels Synthesized by Hydrothermal Methods; 3) Acceleration Response Spectrum and Effective Duration of Lebak Earthquake January 23, 2018 in Jakarta Region; 4) Analysis The Effect of Primary Coil Length of Transformator to The Resulted Electromotif Force; 5) Heating and Quenching Procedure on The Making of Traditional Blacksmith Steel With High Quality.