This issue Vol. 4 No. 1, June 2025 – Journal of Engineering and Science presents a spectrum of engineering research unified by threads of sustainability, multi-criteria performance optimization, design innovation for resource-constrained contexts, and the enhancement of access to engineering education. The first article addresses an urban environmental issue by examining the influence of moisture variation on NH₃ and H₂S emissions during municipal solid waste drying, offering potential insights for odor mitigation and improved occupational safety at processing facilities. The second article advances material evaluation methodology through the application of Grey Relational Analysis to integrate diverse quality parameters of composite particleboard into a unified performance index, accelerating the determination of optimal process combinations. The third article focuses on small-scale renewable energy generation in low wind speed regions by comparing the performance of taper and inverse taper turbine blades, emphasizing geometric adaptation to improve start-up torque and energy capture efficiency. The fourth article explores the fatigue resistance of thermoplastic polyurethane composites reinforced with sugar palm fiber, highlighting the potential of locally sourced bio-based materials for light to semi-flexible cyclic applications. The fifth article presents strategies for enhancing the performance of low-cost DC motors for educational purposes, balancing electromechanical efficiency, operational stability, and affordability. Collectively, the issue illustrates a research direction that combines environmentally friendly technologies, natural resource-based materials engineering, measured optimization, and the democratization of engineering learning tools—reflecting a commitment to innovation that is both practically relevant and responsive to contemporary sustainability challenges. (Note: This description is based on available table of contents information.)