Tan, Wei Jim, Zulkifli Mohamad Ariff, Arjulizan Rusli, and Muhamad Sharan Musa. 2026. “A Modular, 3D-Printed, and Cost-Effective Near-Infrared Spectrometer With Machine Learning for Commodity Plastic Identification”. IIUM Engineering Journal 27 (3):403-15. https://doi.org/10.31436/iiumej.v27i3.4388.