Given the growing demand for increased energy capacity and power density in battery systems, ensuring thermal safety in lithium-ion batteries has become a significant challenge for the coming decade. Effective thermal management plays a crucial role in battery design optimization. Air-cooling temperatures in vehicles often vary from ambient due to internal ventilation, with external air potentially overheating due to vehicle malfunctions. This article highlights the efficiency of lateral side air cooling in battery packs, suggesting a need for further exploration beyond traditional front side methods. In this study, we examine the impact of three different temperature levels and two distinct air-cooling directions on the performance of an air-cooling system. Our results reveal that the air-cooling direction has a more pronounced influence compared with the air-cooling temperature. By employing an optimal air-cooling direction and ambient air-cooling temperature, it is possible to achieve a temperature reduction of approximately 5 K in the battery, which otherwise requires a 10 K decrease in the air-cooling temperature to achieve a similar effect. Therefore, we propose an empirical formula for air-cooling efficiency under various conditions, aiming to provide valuable insights into the factors affecting air-cooling systems for industrial applications toward enhancing the fire safety of battery energy storage systems.

The cellular automata (CA) model has been a meaningful way to study pedestrian evacuation during emergencies, such as fires, for many years. Although the time step used in the CA model is one of the most essential elements, there is a lack of research on its impact on evacuation time. In this paper, we set different time step sizes in an extended cellular automaton model and discuss the effect of time step size on the overall evacuation time under different emergency types and levels. For a fixed step time mode, the larger the time step, the longer the evacuation time. In each time step size, the evacuation time gradually increases with the increase of emergency level, and there is a sharp increase when the time for pedestrians to move one step is exactly an integer multiple of the time step. When there is no friction between pedestrians, the evacuation time at each time step first decreases slightly with the increase of emergency level and then remains unchanged; the larger the time step, when the evacuation time remains unchanged, the lower the emergency level and the greater the evacuation time. For the variable time step model, when the friction between pedestrians approaches infinity, the total evacuation time does not change with the emergency level; when the friction between pedestrians is reduced, the total evacuation time slightly decreases with the increase of the emergency level. The less friction there is, the more significant the reduction. The results of previous actual experiments are also reflected in the simulation at a lower emergency level. The result shows that the time step size significantly impacts the evacuation simulation results of the CA model, and researchers should choose carefully to obtain more realistic simulation results.

Understanding exit choice behaviour is essential for optimising safety management strategies in building evacuations. Previous research focused on contextual attributes, such as spatial information, influencing exit choice, often using utility models based on monotonic functions of attributes. However, during emergencies, evacuees typically make rapid, less calculated decisions. The choice of context can significantly impact the evaluation of attributes, leading to preference reversals within the same choice set but under varying context conditions. This cognitive psychological phenomenon, known as context effects, encompasses the compromise effect, the similarity effect, and the attraction effect. While researchers have long recognised the pivotal role of context effects in human decision making, their incorporation into computer-aided evacuation management remains limited. To address this gap, we introduce context effects (CE) in a social force (SF) model, CE-SF. Evaluating CE-SF’s performance against the UF-SF model, which considers only the utility function (UF), we find that CE-SF better replicates exit choice behaviour across urgency levels, highlighting its potential to enhance evacuation strategies. Notably, our study identifies three distinct context effects during evacuations, emphasising their importance in advancing safety measures.

The catalytic conversion of polyolefin waste into valuable hydrocarbons strongly depends on the atomistic structure of zeolite, yet the fundamental interactions between polypropylene (PP) degradation intermediates and zeolite active sites remain insufficiently understood. In this work, the active-site chemistry of HZSM-5 during PP pyrolysis is systematically investigated by integrating experimental catalytic pyrolysis, reactive molecular dynamics (ReaxFF-MD) simulations, and density functional theory (DFT) calculations. The influence of the framework, including Si/Al ratio, isolated Al T-site location, paired Al configurations, and metal-modified active sites, is examined to elucidate how nanoscale catalytic environments regulate radical reactions during PP decomposition. ReaxFF-MD results reveal that the catalytic behaviour of HZSM-5 is highly sensitive to the spatial configuration of framework aluminium. A Si/Al ratio of 60 achieves the highest gas yield (41.8 %) and exhibits pronounced selectivity towards propylene (C3H6), while the Si/Al ratio of 30 favours the production of gasoline-range hydrocarbons (38.5 %). Additionally, the T8 site provides the most favourable environment for converting large hydrocarbon intermediates into gas yield (46.4 %) with the lower Fermi level (-3.331 eV) and adsorption energy (7.426 eV), suggesting a lower energy barrier for polymer degradation. DFT analysis further shows that cooperative paired Al sites (T5-T11) enhance the adsorption and stabilisation of reaction intermediates with the lowest Ef of -6.574 eV and adsorption energy of 3.045 eV, thereby facilitating radical cracking pathways. In addition, Fe-modified HZSM-5 significantly improves propylene formation (54.9 %) by promoting intermediate activation and hydrogen transfer reactions. Overall, fundamental insights via ReaxFF-MD simulation results have been provided in this work, revealing molecular-level interactions of zeolite-catalysed polyolefin degradation, which offer important insights towards nanoengineering of HZSM-5 catalysts for high-efficient plastic upcycling.