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Predictive modeling of stress intensity factors in composite-repaired cracked aluminum plates : a finite element-based computational framework
Zouambi, Leila; Fekirini, Hamida; Bouafia, Farida; Khodja, Malika (Taylor and Francis, 2026-03-11)
The utilization of bonded composite patches for repairing fatigue-related damage in metallic structures has been acknowledged as an efficient and cost-effective approach, especially within the aerospace sector. However, accurate prediction of stress intensity factors (SIFs) in such repairs remains challenging for structural engineers. This work examines the mechanical behavior of a cracked AA2024T3 plate repaired with a carbon/epoxy composite patch under Mode I loading using finite element analysis (FEA). The study incorporates numerical results to develop a new computational model for precisely determining the repaired plate’s SIF. The developed predictive model, derived directly from FEA data analysis, demonstrates high accuracy with deviations ranging from 0.0006 to 0.0037 when compared to the finite element results. The model successfully predicts repair effectiveness and quantifies the patch’s influence on stress concentration near the crack tip. This computational framework offers a reliable method for forecasting repair efficacy and serves as a practical tool for structural engineers in the analysis and optimization of composite patch repairs. The high-precision model enables improved design decisions for structural repair applications.
A two-level hierarchical optimization framework for grid-connected photovoltaic-wind-battery systems in greenhouse energy management
Ren, Zhiling; Xu, Meng; Zhao, Zilong; Wang, Xinran; Guo, Jia; Dong, Yun (Elsevier, 2026-06)
Greenhouse operations are energy-intensive and face increasing pressure from high operational costs, carbon emissions, and grid reliability constraints. This study develops a grid-connected photovoltaic-wind-battery hybrid energy system and proposes a two-level hierarchical optimization framework for greenhouse energy management. At the upper level, greenhouse operations are optimized using two alternative strategies: energy demand minimization, which aims to reduce heating, cooling, and ventilation loads, and energy expense minimization, which focuses on minimizing energy costs under time-of-use electricity tariffs. At the lower level, energy system scheduling is addressed through renewable energy utilization maximization and comprehensive cost minimization strategies, the latter accounting for electricity purchases, battery degradation, and carbon emissions. Simulation results demonstrate that the comprehensive cost minimization strategy achieves the best overall balance between economic performance and environmental benefits, reducing total operational costs by 45.30% and carbon emissions by 69.25% compared with the baseline. Sensitivity analysis further reveals that the battery unit cost is the most influential factor affecting the economic performance of the system. The proposed framework provides practical guidance for designing cost-effective and low-carbon greenhouse energy systems, supporting reliable and sustainable energy networks.
Promoted bubble dynamics by S-site-induced Cu nucleating agent on the NiFe-based array electrode for efficient oxygen evolution process
Jiang, Runlai; Wang, Hanxiao; Wang, Zheng; Jiang, Yuanye; Gunasekaran, Sundaram; Wang, Xuyun; Liu, Jian; Song, Hongbing; Ren, Jianwei; Wang, Rongfang (American Chemical Society, 2026-03-09)
Please read abstract in the article.
Nurse leaders’ perceptions of existing followership practices : a descriptive qualitative study
Mamba, Welile Magnificent; Fourie, Willem; Heyns, Tanya (Elsevier, 2025)
INTRODUCTION : The success of healthcare organizations depends on partnerships between leaders and followers. Nurses need to be competent in both leader and follower roles because leader–follower relationships in nursing are interdependent rather than linear. However, nursing followership has been understudied. AIM : To explore nurse leaders’ perceptions of existing followership practices. MATERIALS AND METHODS : This descriptive qualitative study purposively selected 10 nurse leaders (top and middle management). Face-to-face, semi-structured, in-depth interviews were used to collect data. The audio-recorded interviews were transcribed verbatim and analyzed using Braun and Clarke’s method. FINDINGS : Participants perceived followership as a hierarchical role but were able to describe the characteristics of the “ideal” follower. Participants described the presence of leadership and follower support while functioning in the follower role. However, lack of leadership supervision and poor teamwork were reported to negatively influence the follower role. There was no formal followership training for participants to become effective followers. Moreover, nurse leaders lacked leadership knowledge and skills as they did not receive formal training while still followers. CONCLUSIONS : Followership education can dismantle the hierarchical view of the follower role. Leadership and follower support enhances follower role performance. Future research should explore followership development needs for nurses in hospital settings. IMPLICATION FOR NURSING MANAGEMENT : Lack of understanding the follower role is a limitation in healthcare teams. Nurse managers need to understand followership as a complimentary role to leadership and provide support to followers.
Violent protest actions during COVID-19 in South Africa : a practical theological response
Buqa, Wonke (AOSIS, 2025-06-05)
South Africa is rated as one of the highest in violent crimes that result in murder, standing at number four in the world. In 2023, there were 27 000 people reported murdered, which amounts to 45 people per 100 000. Violent protest actions are also a contributor to the number of deaths. One particular protest in July 2021 claimed more than 300 lives during the coronavirus disease 2019 (COVID-19) pandemic. The outbreak of the COVID-19 pandemic has been met with strikes, violence, and protests despite policies against such crowd gatherings. The study argues that violent protests are a result of the corruption system, mismanagement, and poor service delivery in the post-apartheid government. The study seeks to investigate the phenomenon of violent protest action during the intense COVID-19 pandemic. Moreover, the study argues that political instability, social injustices, economic stress, societal uncertainty, and the COVID-19 pandemic exacerbated pre-existing toxic social norms and inequalities in South Africa. Therefore, this study affirms that violent protest is a forceful demonstration of an underprivileged group protesting for 'salvation' and 'liberation' from economic struggles. Furthermore, this study proceeds to a transversal interdisciplinary approach where practical theology and psychology as sciences can share their critical concern and voices through a literature review. In this situation, contextually, practical theology must contribute constructively to listening to people's needs and respond to violence cautiously by presenting hope and reconciliation to the devastated communities. CONTRIBUTION : This study contributes to the interdisciplinary discourse of theology and psychology on violence among the underprivileged of South Africa, who through their protest action, demonstrate that indlala nomsindo zinamanyala [hunger and anger are obscene], and they know no boundaries. This study is relevant for practical theology and psychology because both disciplines are concerned with the social welfare and well-being of the people.