Water diversion projects are widely implemented to address water scarcity, improve water quality, and restore ecological conditions in degraded aquatic systems. This study applies a process-based hydrodynamic-environmental model to investigate the dynamics of eutrophication and the representative antibiotic tetracycline in Chaohu Lake under the influence of the Yangtze–Chaohu Water Diversion Project. To explore the influence of different diversion pathways, two numerical scenarios were developed representing two alternative water diversion options: western and eastern routes. The model was validated against field data, achieving Nash–Sutcliffe efficiency values ranging from 0.34 to 0.80 and absolute relative differences between 9.31% and 18.64%, indicating satisfactory performance. Assessment results revealed that tetracycline posed high ecological risks during summer, while nutrient concentrations and eutrophication levels remained within mild to moderate ranges throughout the study period. Comparison of the two scenarios indicated that the western route more effectively reduced ecological risks, yielding annual reductions of 9.12% in total phosphorus, 13.68% in chlorophyll-a, and 11.5% in tetracycline concentrations. This study provides critical insights for optimizing the operation of water diversion projects and supports the sustainable management of aquatic ecosystems, particularly in mitigating the combined threats of eutrophication and antibiotic pollution.

The inevitably formed residual stress in the Selective Laser Melting (SLM) process leads to distortion, crack and even delamination of the workpiece. Single laser is commonly applied during SLM processing. However, its productivity is much lower than multiple lasers. In addition, the research of residual stress with multi-laser condition currently is limited in the open documents. In this paper, a three-dimensional (3D) thermo-mechanical model, with considerations of temperature dependent properties of Ti-6Al-4V, phase change and convective flow, is developed at first. Then, the numerical results of maximum temperature and dimensions of the molten pool are validated by available experimental data. Furthermore, a parametric study in regards to a series of scan strategies is investigated. According to the simulation results, the residual stress increases significantly when the laser number reaches four. The “two-zone technique” scan strategy decreases the equivalent residual stress by 10.6% compared to the successive scan strategy. With a shortening scan length, the residual stress first increases slightly, then decreases dramatically and attains the minimum when it is a quarter. Furthermore, for the multi-laser SLM process, carefully planning the scanning sequence and the sweeping direction to decrease heat concentration is beneficial in controlling the residual stress.