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Efficient photocatalytic degradation of metoprolol using activated carbon supported NiFe-layered double hydroxides (NiFe-LDH/C) under solar-driven simulation
Biata, Raphael N.; Mabhulusa, Wendy; Mofokeng, Lethula E.; Ratshiedana, Rudzani; Munonde, Tshimangadzo S.; Nxumalo, Edward N. (KeAi Communications Co., 2025-09)
The efficient photocatalytic degradation of pharmaceuticals in wastewater is critically important for environmental protection. The synthesis and characterization of NiFe-LDH/C for the photocatalytic degradation of selected β-blockers, specifically metoprolol, under UV light conditions were investigated in this study. The study aimed to explore the potential of NiFe-LDH/C as a catalyst for the degradation of metoprolol, a commonly used pharmaceutical compound in the treatment of chronic diseases such as high blood pressure and chest pains, which is frequently detected in wastewater. The selection of NiFe-LDH/C was driven by the need for materials with high photocatalytic activity, the ability to generate reactive oxygen species and enhance charge separation, and stability under solar light. Activated carbon was employed as a support to increase the surface area and improve the dispersion of the LDH particles, thereby enhancing overall photocatalytic efficiency. The results showed that NiFe-LDH/C exhibited excellent photocatalytic activity in degrading metoprolol under both UV and sunlight-mediated conditions, with degradation efficiencies of over 89 %. Furthermore, the characterization of the NiFe-LDH/C catalyst revealed its stability and recyclability, making it a promising candidate for the efficient removal of pharmaceutical compounds from wastewater through photocatalytic degradation. The characterization results showed that the NiFe-LDH/C exhibited a high degree of crystallinity and a well-defined layered structure. The photocatalytic experiments demonstrated that the NiFe-LDH/C was effective in degrading metoprolol and ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) was used to elucidate the degradation products of metoprolol in water.
Multi-objective optimization of load flow in power systems: an overview
Nyingu, Bansendeka Theo; Masike, Lebogang; Mbukani, Mwana Wa Kalaga (MDPI, 2025-11-20)
The expanding complexity of power systems—driven by the motivation to reduce their carbon footprint by integrating renewable energy sources (RESs) in the grid, the increasing energy demand, grid scalability, and the necessity for reliable and sustainable operation—has made the optimal power flow (OPF) problem the main issue in power systems. Hence, the concept of muti-objective optimal power flow (MOOPF) in power systems has become a crucial tool for power system management and planning. This article provides an overview of recent optimization techniques in power systems that have MOOPF as their central problem, as well as their applications in power systems, with the purpose of identifying significant approaches, challenges and trends when it comes to large-scale probabilistic MOOPF. This overview was developed based on an in-depth analysis of MOOPF techniques, the classification of their applications, and the formulation of the problem in power systems. This overview contributes to the existing literature by highlighting the evolution of optimization techniques, and the need for robust, probabilistic hybrid optimization techniques that can address variability, uncertainty, reliability, and sustainability in power systems. These findings are significant because they emphasize the current transition towards more adaptive and intelligent optimization strategies, which are essential to developing sustainable, dependable, and effective power systems, especially as we move towards smart grids and low-carbon energy systems.
Investigating the patterns of tree cover and density in relation to abiotic and biotic factors in Kruger National Park
Riccardi, Tullia; D’Ammando, Giacomo; Wilson, Lucy; Attorre, Fabio; Davies, Andrew; Farcomeni, Alessio; MacFadyen, Sandra; Strydom, Tercia; Smit, Izak P.J.; Malatesta, Luca (Wiley, 2025-11)
Across savanna ecosystems worldwide, the decline of large trees and the rapid expansion of shrubs present major conservation challenges. These trends are especially pronounced in South Africa's Kruger National Park (KNP), the country's largest protected area. To quantify their extent and identify their drivers, we conducted a spatial assessment of tree cover and density across KNP from 2011 until 2022. We then evaluated how these response variables are influenced by abiotic factors, including fire, climate, soil, and geology, and by biotic factors, such as the densities of African elephant adult male bulls and herds, including females and calves. We defined trees as land-cover elements that cast a distinct shadow and stand taller than 5 m. Using Collect Earth, an open-source software for augmented visual interpretation of high-resolution satellite imagery, we assessed tree cover and density on 4258 plots of 0.5 ha each. We recorded 27,918 trees, equivalent to an average density of 13 trees/ha. Counts in each plot were truncated to a maximum of 30 individuals. We validated our estimates of tree cover and height against independent, high-resolution airborne LiDAR measurements, which yielded an RMSE of 8.89% for trees taller than 3 m. The relative influence of selected predictors on tree cover and density was analyzed through logistic and survival regressions. Geology had the greatest influence on tree distribution, where both tree cover and density were higher on nutrient-poor granitic substrates than on nutrient-rich basalts. Tree cover and density were higher in areas with low fire frequency, close to main rivers, and with higher sand content in the soil. The mean annual rainfall showed a positive correlation with tree cover, while it had a negative correlation with the number of trees. Elephant bulls were found to be negatively correlated with both tree cover and density. In contrast, elephant herds exhibited a positive correlation with tree cover and density. This study highlights the importance of understanding the effects of multiple factors on tree distribution and aims to provide a baseline for assessing tree cover and density across KNP to support ongoing tree management strategies and contribute to future conservation priorities.
Self-reported vocal demands, perceptions, and knowledge of occupational voice users in South Africa
Vermeulen, Rouxjeanne; Du Toit, Maria; Van Lierde, K.M. (Kristiane); Graham, Marien Alet; Van der Linde, Jeannie (Elsevier, 2025-07)
OBJECTIVES : The study aimed to describe daily vocal demands, perceptions and knowledge as reported by occupational voice users. STUDY DESIGN : A descriptive, cross-sectional research design was employed. METHODS : A survey on vocal demands, perceptions and knowledge was distributed to 102 occupational voice users via a snowball sampling technique. RESULTS : Slightly more than half of the participants (55%) reported using their voice for work 36.5 hours a week on average (SD = 15.5, range: 33–40). Participants reported that, on average, their daily voice use is 6.3 hours (SD = 2.7) for work and the majority (81%) reported a decrease in voice quality after work; Three-quarters (75%) also reported vocal fatigue at the end of day. Approximately one-third (33%) reported being exposed to environments where they are expected to shout, scream or cheer loudly. More than half of the participants (61%) reported that they have previously received vocal health education but 40% reported that they felt this training was insufficient. High vocal demands are significantly correlated to an increase in perceived vocal handicap rs = 0.242; (P = 0.018), tiredness of voice rs = 0.270; (P = 0.008), physical discomfort rs = 0.217; (P = 0.038) as well as how occupational voice users experience improvement of symptoms with rest rs = −0.356 (P < 0.001). Other risk factors highlighted by occupational voice users are the ingestion of liquid caffeine, alcohol, and carbonated drinks, smoking or the presence of chronic cough, chronic laryngitis, and gastroesophageal reflux disease. CONCLUSIONS : Occupational voice users are subjected to high daily vocal demands that can be seen to be linked to vocal fatigue, changes in voice quality and vocal symptoms experienced. It is essential that occupational voice users as well as treating clinicians are aware of certain significant predictors of both vocal handicap and vocal fatigue. These findings provide insights for developing strategies for training and cultivating vocal health consciousness and preventive voice care initiatives that focus on occupational voice users in South Africa.
UDI editorial winter issue 2025
Landman, Karina; Aelbrecht, Patricia (Palgrave Macmillan, 2026)
Shaping quality environments and public interest outcomes through urban design governance