Wind turbine drivetrains are flexible mechanical systems prone to torsional oscillations, particularly when modeled as a two-mass system consisting of rotor inertia, generator inertia, and a flexible shaft. These oscillations can increase mechanical stresses, accelerate fatigue damage, and reduce power quality if not properly controlled. Shaft damping plays a critical role in shaping the dynamic response of the drivetrain, but it also introduces a trade-off between vibration suppression and energy efficiency.

This paper investigates the effect of shaft damping on the dynamic performance of a wind turbine drivetrain modeled as a two-mass system. Transfer function models for rotor speed, generator speed, and shaft torque were derived, and both time-domain and frequency-domain analyses were performed. Step responses were used to evaluate transient metrics such as overshoot, oscillation amplitude, and settling time, while Bode diagrams captured resonance behavior and frequency sensitivity. The cumulative energy dissipated in the shaft was also computed to assess efficiency impacts.

The results show that low shaft damping produces sharp resonance peaks and sustained oscillations, leading to poor dynamic stability. Increasing damping reduces oscillations, suppresses resonant modes, and improves torque transmission smoothness. However, higher damping levels also result in greater energy dissipation, reducing drivetrain efficiency. These findings highlight the need for optimal damping selection to balance mechanical stability with energy performance. This study provides insights into the design and optimization of wind turbine drivetrains, contributing to improved reliability and overall system performance.

Access to reliable and affordable energy is a key barrier limiting the adoption of controlled-environment farming in rural regions. This study evaluates the performance of Mushroom Kothi, a low-cost IoT-enabled cultivation chamber, when powered by solar photovoltaic panels, and quantifies its environmental benefits through energy use analysis and life cycle assessment (LCA). Experiments were carried out in Saeedpur Khas village, Prayagraj (Uttar Pradesh), where the device was operated under two scenarios: (i) conventional grid electricity supply and (ii) off-grid solar panels with battery backup. Power consumption was continuously monitored across full mushroom crop cycles, and energy savings were estimated against regional grid electricity baselines. In addition, a streamlined LCA was performed using the AWARE method to assess water stress implications and broader sustainability impacts. Results showed that the device consumed less than 100 W peak, and a 150 W solar panel with a small battery was sufficient to power chamber operations throughout the cultivation cycle. Solar integration reduced grid dependency by over 85%, resulting in significant cost savings and estimated CO₂ emission reductions of 0.35–0.45 kg per kg of mushrooms produced. The AWARE analysis further indicated lower water stress impacts compared with conventional open-shed cultivation due to improved microclimate regulation. These findings demonstrate that solar-powered controlled chambers can provide an energy-efficient, climate-resilient, and environmentally sustainable solution for smallholder mushroom farming. The approach holds particular relevance for the Global South, where energy insecurity and resource constraints are major challenges to scaling sustainable agriculture.

Many therapeutic and nutritional benefits have been attributed to the different parts of Prosopis africana in numerous studies. This study investigated the effect of Prosopis africana leaf extract on inflammatory and oxidative stress markers in rats experimentally induced with obesity. Twenty Wistar albino rats (n = 5) were divided into a non-obese control group and three obese groups. The obese groups were first maintained on a high-fat diet for ten weeks before treatment. One of the obese groups served as the untreated control, while the remaining two groups were treated with 200 mg/kg and 400 mg/kg of the P. africana leaf extract (with return to normal diet), respectively. Serum TNF-α, IFN-γ, and MDA levels were measured after 28 days of treatment. The results showed that the untreated obese group had significantly (p < 0.05) elevated levels of TNF-α, IFN-γ, and MDA compared to the non-obese control. In contrast to the untreated obese group, the treatment groups exhibited significantly reduced levels of these parameters, with the most pronounced effect observed at the highest extract dose. This result highlights the potential therapeutic benefits of P. africana leaves in reducing obesity-related inflammatory processes, further supporting the health benefits that have been reported with the use of P. africana leaves.

Occupant behavior significantly influences residential energy consumption, yet traditional energy modeling practices commonly rely on fixed activity schedules, neglecting dynamic behavioral variations. Among household activities, Dishwashing is a notable yet often overlooked contributor to residential energy demand, as it involves both electricity and hot-water use. Its frequent occurrence after dinner significantly adds to evening peak loads. To address this gap, this study develops a high-resolution, data-driven framework specifically focused on modeling residential dishwashing behavior to support demand-flexible energy management strategies. Utilizing detailed temporal data on dishwashing activities extracted from the American Time Use Survey (ATUS), complemented by relevant household and temporal covariates, this research applies advanced machine-learning algorithms to predict both the probability and timing of dishwasher operation. The resulting occupant-informed load profiles are integrated into comprehensive building energy simulation models, facilitating the assessment of peak-shifting potential, energy-efficiency improvements, and demand-response effectiveness. Findings from this analysis provide enhanced predictive accuracy for energy demand, inform the development of occupant-centered appliance control strategies, and yield actionable insights and recommendations for incentive design and retrofit policies. Furthermore, the proposed modeling framework offers flexibility for adaptation to other occupant-driven activities, promoting broader scalability in occupant-centric energy modeling and supporting the transition toward resilient, low-carbon energy systems.

In the context of current climate change, extreme weather events such as heatwaves are becoming more frequent. These events have a particularly severe impact in urban environments due to the urban heat island effect. Providing thermal comfort for people using open public spaces requires localised cooling strategies, particularly in areas with high footfall, such as transport hubs, squares and promenades. Adiabatic cooling is a promising solution as it can lower air temperatures in an energy-efficient manner with relatively low environmental impact. This article provides an overview of current adiabatic outdoor cooling systems, assessing their energy, economic and environmental efficiency and considering various options for achieving comfortable temperatures. Particular attention is paid to integrating systems with renewable energy sources, such as solar power, and to determining the optimal 'cooling point' at which the system can operate autonomously, without the need for additional electrical power. The results demonstrate that, when properly sized and designed, adiabatic cooling systems can significantly enhance thermal comfort in urban outdoor spaces while minimising energy consumption. This represents a promising adaptive strategy in response to increasingly frequent urban heatwaves. The paper provides practical design guidelines and lays the groundwork for further research into the sustainable cooling of occupied outdoor spaces.

The escalating demand for sustainable packaging materials has driven research into biodegradable polymers derived from agricultural and industrial waste. This study focuses on the development and physicochemical characterization of novel antibacterial bioplastic films based on chemically modified banana (Musa paradisiaca) peel starch and chitosan. Starch was first extracted from banana peels and subsequently subjected to a chemical modification, such as acetylation, to enhance its thermoplastic properties and reduce its inherent hydrophilicity. The modified starch was then blended with a chitosan solution at various concentrations to formulate a composite film-forming solution. The bioplastic films were fabricated using the solution casting method, followed by a controlled drying process.

A comprehensive characterization was performed to evaluate the resulting films. Fourier-Transform Infrared Spectroscopy (FTIR) was employed to confirm the success of the chemical modification and to identify intermolecular interactions between the starch and chitosan polymers. The crystalline structure of the films was analyzed using X-ray Diffraction (XRD), while Scanning Electron Microscopy (SEM) was used to investigate the surface and cross-sectional morphology. Key physical properties, including tensile strength, elongation at break, water vapor permeability (WVP), and thermal stability via Thermogravimetric Analysis (TGA), were systematically measured. Finally, the antibacterial efficacy of the composite films was quantitatively assessed against common foodborne pathogens, such as Escherichia coli and Staphylococcus aureus, using the agar diffusion method. This methodology provides a framework for evaluating the potential of these biocomposites as a high-performance, eco-friendly packaging alternative.

Golf is generally perceived as a safe and moderate sport; however, in middle-aged and older adults, it can pose significant health risks, including sudden cardiac events. Particularly during putting on the green, repetitive squatting and standing motions combined with psychological pressure may increase the risk of stroke or other cardiovascular incidents. In this pilot study, we aimed to investigate whether biometric signals can capture mental tension during golf play. Four healthy male participants were monitored while playing a full round of golf. We used a Holter ECG and a wearable pulse wave sensor to collect physiological data, including three-axis acceleration, R–R intervals (RRI), and heart rate variability (HRV) indices such as SDNN, LF, HF, and LF/HF ratio. Our analysis revealed no clear correlation between composite acceleration and RRI during the play. However, SDNN, LF, and HF values showed a tendency to increase by the final hole compared to the first hole, suggesting progressive autonomic adaptation or accumulated tension. Moreover, the LF/HF ratio decreased after play in all participants, indicating a shift toward parasympathetic dominance and a relaxation trend. These findings suggest that biometric signals, especially HRV indices, may reflect mental and physical changes during golf, potentially providing useful indicators for monitoring cardiovascular strain and risk in older adults engaged in this activity.

Polyhydroxyalkanoates (PHAs) are biodegradable polyesters synthesized by microorganisms and have attracted significant attention as sustainable alternatives to petroleum-based plastics. Accurate quantification of intracellularly accumulated PHAs often requires complex pretreatment procedures, including polymer extraction and purification. In this study, we propose a simplified and reliable method for the quantification of PHAs based on alkaline decomposition followed by high-performance liquid chromatography (HPLC). We focused on the copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)], which consists of two monomer units: 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV). Under alkaline conditions, these monomers are decomposed into 2-butenoic acid (2BE) and 2-pentenoic acid (2PE), respectively. The molar conversion factors from PHB to 2BE (α) and PHV to 2PE (β) were experimentally determined through calibration curves constructed using both commercially available standards and alkaline-treated PHA samples. These constants were then used to calculate the concentrations of PHB and PHV. The conversion factors were calculated to be α = 3.26 and β = 3.30. Standard P(3HB-co-3HV) samples were analyzed using this method, and the measured values closely matched the theoretical concentrations, confirming the method's accuracy. This approach simplifies PHA quantification without compromising reliability and eliminates the need for solvent-based extraction. Future work will explore the applicability of this method for analyzing intracellular PHAs in bacterial cells, potentially streamlining PHA analysis in various environmental and industrial settings.

Nelsonia canescens is traditionally used to treat infections. This study evaluated its phytochemical composition and antimicrobial activity to validate ethnomedicinal claims. The methanol extract and fractions (hexane, chloroform, ethyl acetate, and butanol) were screened for phytochemicals and tested against Staphylococcus aureus, Escherichia coli, Salmonella typhi, Candida albicans, and Aspergillus niger using agar diffusion and broth dilution methods, with ciprofloxacin and fluconazole as controls. Phytochemical analysis revealed flavonoids, saponins, tannins, alkaloids, and cardiac glycosides. Antimicrobial assays showed that the butanol fraction (BF) and an isolated compound (IS) exhibited strong activity, with inhibition zones of 30–36 mm (S. aureus) and 28–30 mm (E. coli). The ethyl acetate fraction (EAF) showed moderate antifungal effects (17 mm against C. albicans). IS had the lowest MIC values (2.5–10 mg/ml), comparable to ciprofloxacin (1.25–2.5 µg/ml), and demonstrated bactericidal effects (MBC: 5–50 mg/ml). Non-polar fractions (CME, HF, and CF) were inactive, while fluconazole was effective only against fungi (MIC/MFC: 1.25–2.5 µg/ml). Polar fractions (BF, EAF) and IS displayed promising antimicrobial activity, particularly against Gram-positive bacteria and C. albicans, though standard drugs were more potent. The presence of bioactive compounds supports N. canescens traditional use, highlighting its potential as a source of natural antimicrobial agents. Further optimization could enhance efficacy.

Per- and polyfluoroalkyl substances (PFASs) are synthetic chemicals widely applied in industrial processes and consumer products due to their thermal stability and resistance to degradation. However, these same properties make PFASs environmentally persistent and a potential threat to human health. Although international concern about PFAS exposure has grown, limited research has explored their effects in African populations. This study investigated the serum levels of three PFASs—perfluorooctanoic acid (PFOA), perfluorooctanesulfonate (PFOS), and perfluorobutane sulfonate (PFBS)—and their association with diabetes mellitus (DM) in a mixed-ancestry population from Bellville South, Cape Town, South Africa. Serum samples (n = 179) were analyzed using liquid chromatography–tandem mass spectrometry (LC–MS-8030), and statistical analyses were performed with STATISTICA software. All three PFASs were detected in every sample, with PFOA showing the highest mean concentration (9.43 ± 13.16 ng/mL). Concentrations were generally higher in females than males, with PFOA levels significantly elevated among women (p = 0.0116). Despite these exposures, no statistically significant associations were observed between PFAS concentrations and glycaemic status, obesity, or other metabolic predictors (p > 0.05). Notably, PFOS demonstrated a modest positive correlation with HbA1c in females, suggesting potential gender-specific interactions. While our findings did not establish a clear link between PFAS exposure and DM, they highlight measurable human exposure within this community and emphasize the need for further research. Given the widespread detection of PFASs in environmental matrices and medicinal plants in South Africa, larger-scale longitudinal studies are warranted to clarify exposure pathways and potential health implications.