Development of Eco-friendly Antimicrobial Bricks Using Nickel Slag Waste Enriched with TiO2 to Counteract E. coli Contamination L. Agusu, W. O. Nurtia, M. Z. Muzakkar, I. W. Sutapa, Y. Ishikawa, Y. Fujii, T. Asano, S. Mitsudo, Y. Tatematsu International Journal of Acta Material Vol. 2 No. 1 2025 DOI 10.62749/ijactmat.v2i1.20