Boosting the heat absorption efficiency in latent heat thermal energy storage (LHTES) systems continues to pose a major hurdle, primarily because phase change materials (PCMs) typically exhibit poor heat conduction properties. As a result, enhancing thermal transmission inside these systems is vital for accelerating energy accumulation and elevating overall operational effectiveness. This study employs computational fluid dynamics to investigate the charging thermal behaviour of PCM in a novel vertically oriented shell-and-tube LHTES system equipped with twisted fins of different configurations. The numerical model was developed using ANSYS 2024R1 and first validated against experimental data. The effectiveness of the design configurations was next evaluated by comparing non-perforated and perforated twisted fins with three perforation densities (sparse, moderate, and dense) against a baseline configuration without fins under identical operating conditions. The findings reveal that the charging time of baseline configuration was reduced by 46.50%, 49.30%, 53.52%, and 59.16% when using non-perforated twisted fins, sparsely perforated fins, moderately perforated fins, and densely perforated fins respectively. Compared with the non-perforated twisted fin design, the enhancement effectiveness of perforated fins increased from 1.06 for sparse perforations to 1.30 for dense perforations. This improvement indicates that increasing perforation density promotes additional convective mixing while maintaining adequate conductive heat transfer pathways, making densely perforated twisted fins the most effective configuration.
This article introduces the concept of improvised pragmatism of care to analyze how Indigenous communities, living in and around protected areas navigate animal health amidst ecological disruption and limited institutional capacities. Drawing on focus group discussions conducted in 2024 in seven communities of the Great Limpopo Transfrontier Conservation Area in Mozambique, we show how livestock care emerges not as static tradition nor simple adoption of biomedical protocols, but as dynamic practices that combine embodied diagnosis, herbal repertoires, and selective engagement with veterinary interventions. These plural strategies constitute resilient responses to epistemic injustice and ontological displacement in a conservation landscape. Improvised pragmatism of care captures this mode of governance from below: an active reconstitution of knowledge and practice under conditions of uncertainty. Our analysis cautions against treating animal health as an abstract, detachable component independent of human–animal relations or as separable from historical trajectories and contemporary territorial and environmental management policies. By foregrounding community improvisation as both epistemic and political practice, this study contributes to veterinary anthropology and health social sciences, highlighting how Indigenous actors can sustain multispecies health in contested landscapes marked by displacement and inequality.
The provision of paediatric and congenital heart disease services in Africa is currently less than 1% of the global surgical capacity. Coarctation of the aorta (CoA) is a common type of congenital heart disease and is influenced by the haemodynamics of blood. Patient-specific computational fluid dynamics (CFD) modelling offers valuable insights into haemodynamics in CoA, but significantly relies on the prescription of accurate outlet boundary conditions. The 3-Element Windkessel (3-EWK) model is an approach that is often used and has been shown to lead to physiologically realistic results. The accuracy of the 3-EWK is contingent on tuning of its lumped parameters (R1, R2, and C). This study quantifies the impact of measurement uncertainties from Doppler Echocardiography on the estimation of each 3-EWK lumped parameter and the resulting haemodynamic outputs from CFD across the cardiac cycle, using a stochastic approach. The results show that the resulting uncertainties in the lumped parameters do not have a significant effect on the bulk flow. This was shown by the variability of the pressure drop across the coarctation, the main clinical parameter, being less than 5%. This was similarly observed for the volume flow rate. Therefore, indicating that when using the 3-EWK model, measurement uncertainties due to Doppler echocardiography have a minor impact on the bulk flow. However, the time-varying inlet volume flow rate profile was seen to have had a more significant effect. Thus, indicating that it is of greater interest when compared to the lumped parameters.
Africa is experiencing a renewed natural resource boom. Heightened demand for the continent’s vast reserves of critical minerals and metals for green energy and technological applications, as well as its ability to serve oil and gas markets in a time of geopolitical turmoil, have triggered increased international interest and investment in African resource sectors. As in previous commodity booms, resource-rich African governments are articulating a desire to leverage natural resource wealth for economic growth and human development. Yet this promise also brings peril, as natural resource endowments have in the past generally failed to translate into improved living standards and economic growth for most resource-rich African states. Whether “this time will be different” for developmental outcomes will be shaped not just by resource endowments, but critically, by the interplay between global geopolitical dynamics, domestic political institutions, and local governance processes.
We present a population-level spectral analysis of fast radio bursts from the second CHIME/FRB catalog using three curvature-radiation–motivated templates: point-source, one-dimensional bunch, and paired-bunch cavity, together with two non-curvature oscillatory baselines. Fits are evaluated with reduced chi-squared χr2, the Akaike information criterion (AIC), the Bayesian information criterion (BIC), and the Ljung–Box residual autocorrelation test. All three templates yield median χr2 values close to unity for both repeating and non-repeating bursts. Repeaters show narrower χr2 distributions than non-repeaters, with statistically significant but modest population-level differences. AIC favours the one-dimensional bunch model for the largest fraction of sources within the curvature-radiation family; BIC also favours the 1d model in both FRB classes, though with a markedly increased relative share for the simpler point-source model. However, residual autocorrelation remains widespread across all models: only 12%–22% of sources simultaneously satisfy goodness-of-fit and residual-independence criteria, indicating persistent structured residuals beyond the tested templates. These results suggest that while curvature-radiation-motivated geometries capture the dominant spectral envelope of many FRBs, additional physical ingredients or spectral components are required to describe the fine-scale spectral structure of the data. Comparison with non-curvature baselines shows that oscillatory modulation is the dominant spectral signature within the CHIME band, with the curvature-radiation envelope not independently constrainable at these frequencies. The inferred effective spatial scales are ∼ 16–18 cm for the one-dimensional model and ∼ 25–28 cm for the cavity model. Their interpretation as bunch lengths or cavity separations is conditional on the assumed emission model.
