This issue comprises five scholarly articles contributed by nineteen authors, presenting recent advances in engineering research through diverse methodological approaches and multidisciplinary perspectives. The published studies collectively demonstrate the integration of experimental investigations, computational modelling, systematic literature review, and systems analysis to address contemporary challenges in engineering, manufacturing, and environmental sustainability.
The issue features research on the influence of post-weld heat treatment on the surface integrity and microhardness of GTAW-repaired aluminium alloys, providing experimental evidence for improving material performance and repair quality. Another contribution employs finite element analysis to evaluate the crashworthiness of a multi-stage aluminium impact attenuator, offering insights into structural optimization for automotive safety applications. Advancing the field of additive manufacturing, a comprehensive literature review critically examines mechanical characteristics and finite element-based non-uniform infill density strategies for Fused Deposition Modelling (FDM)-printed components, identifying current developments, research gaps, and future directions.
Environmental engineering is represented through two complementary studies. The first presents a systematic review of system dynamics applications for integrated domestic wastewater management, emphasizing stock–flow modelling, policy scenario analysis, and river water quality management. The second provides an empirical assessment of floating marine debris by investigating its density, composition, chemical characteristics, and recycling potential, contributing to evidence-based strategies for sustainable coastal and waste management.
Collectively, the articles published in this issue highlight the increasing application of advanced analytical techniques, experimental validation, numerical simulation, evidence synthesis, and sustainability-oriented research in solving complex engineering problems. By bringing together innovative methodologies and practical engineering applications, this issue contributes to the advancement of engineering knowledge, supports informed decision-making, and encourages future interdisciplinary research that addresses both industrial needs and global sustainability challenges.