Aprilliano , Francisko, Nereus Tugur Redationo, and Bernardus Cristanto Putra Mbulu. 2025. “COMPARISON OF VARIATIONS OF ROBUSTA AND ARABIKA COFFEE GROUNDS BY COMPOSITION (60%: 40%, 50%: 50%, 40%: 60%) TO DETERMINE THE HARDNESS AND CALORIFIC VALUE OF BRICKETS”. Mechanical, Energy and Material (METAL) 3 (1):01-07. https://ejournal.widyakarya.ac.id/index.php/metal/article/view/121.