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Fuel and graphite temperatures in a micro nuclear reactor during a DLOFC
Du Toit, Charl; Boyes, Wayne; Slabber, Johan F.M. (Taylor and Francis, 2026)
The Advanced Micro Reactor (AMR), a high-temperature gas-cooled prismatic block reactor, is being designed to produce 10 MW of thermal power. The active core consists of an inner graphite reflector, fuel graphite block assemblies arranged in three rings, and an outer graphite reflector (OR). The system code Flownex SE has been used to set up an axisymmetric network model of the reactor to study the thermal-hydraulic behavior of the reactor under steady-state conditions and during a depressurized loss-of–forced cooling (DLOFC) event. The helium coolant enters the reactor at 320°C, flows up in the risers in the OR to the upper plenum, down through the core, and exists the lower plenum at 750°C. In the risers, the coolant is preheated to 324.8°C. Under steady-state conditions, the top of the core is on average 403°C cooler than the bottom of the core, and the maximum fuel and graphite temperatures are 1032.4°C and 809.0°C, respectively. During the DLOFC, the reactor endeavors to heat up the upper part of the core, cool down the lower part of the core, and set up the required temperature gradient in the radial direction to remove the decay heat and the excess heat accumulated in the solids. When the DLOFC starts and the reactor is scrammed, the fuel temperatures drop steeply, along with the drop in power, until they are in equilibrium with the corresponding graphite temperatures, and then follow the graphite temperatures as the decay heat decreases and the graphite heats up or cools down. This paper focuses among other things on the accumulation and release of heat by the fuel and solids during the DLOFC. The thermal behavior of the inner ring of the fuel block assemblies receives special attention.
From species to pixels : monitoring rangeland quality & productivity by leveraging the NDVI-RCI relationship
Nondlazi, Basanda Xhantilomzi; Cho, Moses Azong; Mantlana, Brian Khanyisa; Ramoelo, Abel (Routledge, 2026)
Grasslands are highly vulnerable to climate and changes in grazing management, yet little is known about the national rangeland response to long-term (>18 years) grazing management that may confound climate effects. This study assessed the correlation between Normalized Difference Vegetation Index (NDVI), i.e., productivity and Rangeland Condition Index (RCI) i.e., quality and predicted historical grazing management (26 years) using Ecological Index Method (EIM) analysis of 72 relevés in the Highland Sourveld (HSV). Relationships between 150 NDVI and 72 RCI samples showed a rate of 0.125 change in NDVI for every 12.5% change in RCI. In 1983, the HSV’s rangeland carrying capacity (RCC) ranged from 2.0 - 2.2 ha/AU/yr (land required to support one mature bovine for 1 year), with an NDVI of 0.43, like the benchmark. site. By 2009, the RCC decreased to 3.2 ha/AU/yr, with NDVI <0.30. Selective overgrazing, reduced RCC by increasing Increaser II species and reducing Decreaser species presence. Findings suggest combining NDVI and RCI is more effective than using either alone. Integrating remote sensing with traditional ecological data (Ecological Remote Sensing - eRS) improves our understanding of rangeland vulnarability, thus, ideal for permanent monitoring of public rangelands in South Africa.
From Lake Victoria to the tap : antibiotic resistance and pathogenic contamination of Kisumu City water supply and wastewater network
Reva, Oleg N.; Sifuna, Anthony; Orata, Francis; Omolo, Caroline; Iramiot, Jacob Stanley; Enright, Mark C.; Mutshembele, Awelani; Zhou, Jian; Shivoga, William A. (Wiley, 2026)
Waterborne diseases and antimicrobial resistance (AMR) pose mounting public health threats across sub-Saharan Africa, particularly in rapidly urbanising regions dependent on untreated or poorly treated surface waters. This study applied shotgun metagenomic sequencing to characterise microbial communities, virulence factors and antibiotic resistance genes (ARGs) in water samples collected from Lake Victoria, River Wigwa, Dunga Water Treatment Plant, Nyalenda Wastewater Stabilisation Ponds and the tap water outlet in post-treatment supply pipe in Kisumu city (Kenya). Bacterial taxa dominated all metagenomes, with 121 classes represented. Cyanobacteria, particularly Planktothrix, were highly abundant in lake and tap water, whereas wastewater and river samples exhibited greater taxonomic diversity. Major human pathogens, including Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Acinetobacter baumannii and Bacillus cereus/anthracis, were detected in nearly all samples, with unexpectedly high prevalence in tap water. Viral indicators of faecal contamination (adenoviruses, enteroviruses and torque teno viruses) corroborated widespread wastewater influence. Functional gene profiling revealed a rich resistome comprising aminoglycoside-modifying enzymes, β-lactamases, vancomycin-resistance operons and disinfectant-resistance determinants. The highest ARG and virulence gene frequencies occurred in tap and treatment-plant water, suggesting that incomplete disinfection and biofilm persistence promote the proliferation and exchange of ARGs between environmental and pathogenic taxa. In contrast, Lake Victoria water exhibited lower ARG abundance, reflecting natural self-purification processes. These findings underscore the inadequate water treatment and open wastewater systems create ecological ‘hotspots’ for ARG selection and horizontal gene transfer. Metagenomic surveillance integrated into One Health frameworks can enhance risk forecasting and guide interventions to mitigate AMR emergence and dissemination in freshwater systems serving over 35 million people across the Lake Victoria basin.
Gaming disorder : prevalence and association with psychosocial outcomes in the German general adult population
Threlfall, David; Althaus, Catherine (Wiley, 2026)
This article surveys the arrival of gameful government into Australian public sector practice. Gameful government is a shorthand, descriptive term denoting the interpenetration of (video)games, and design elements and thinking from them, into public sector work. Knowledge of gameful government is limited, in Australia and internationally, due to localised usage, low visibility, and limited understanding beyond informed observers. Our study partially redresses this under-exploration of public sector games and gamification, both empirically and ethically. To do so, we detail the history of gaming for public sector purposes, a story starting with wargaming. Then, we categorise past and current gameful Australian public sector projects into a typology with five categories: recruitment; training and learning; public communication and policy education; engagement; and implementation and evaluation. We analyse the typology categories and characteristic cases within them. Finally, we assess the benefits and risks of gameful government for citizens and public sector practice. POINTS FOR PRACTITIONERS • Knowledge, skills, and practices from (video)game play and development are increasingly prevalent within the Australian public sector. This article descriptively terms this gameful government. • Despite a range of current use cases—for recruitment, training and learning, public communication and policy education, public engagement, implementation, and evaluation—Australian public sector examples are localised, particularly in Defence. • Realising the potential of games for public sector and societal ends will require broader acknowledgement and understanding of this practice, as part of larger shifts in public sector capability and technological transformation.
Perspectives of primary healthcare nurses on cultural practices contributing to late antenatal booking in South Africa
Maluleke- Ngomane, Sharon H.; Ramavhoya, Thifhelimbilu I. (AOSIS, 2025-09-17)
BACKGROUND : Primary health care (PHC) nurses are crucial in reducing late antenatal booking and early detection of pregnancy-related conditions to enhance the best perinatal outcomes. Research confirms that early antenatal care is a key intervention to safe motherhood, aimed at preventing perinatal adverse events; however, cultural practices of pregnant women have a role to play in late antenatal booking. AIM : This study explored and discussed the cultural practices of antenatal clients that contribute to late antenatal booking as related by PHC nurses. SETTING : This study was conducted at PHC facilities in Mpumalanga province, South Africa. METHODS : Following qualitative phenomenological design, PHC nurses’ perceptions of cultural practices of antenatal clients contributing to delayed antenatal booking were explored and described. Purposeful sampling was followed to sample PHC nurses with three or more years of experience to respond to in-depth, open-ended questions. Colaizzi’s thematic data analysis was used to facilitate emerging themes and sub-themes. Measures of trustworthiness were ensured for this study. RESULTS : Results show that PHC nurses believe that antenatal clients intentionally book late and use herbs and religious interventions. Furthermore, PHC nurses neglect the cultural practices of antenatal clients. CONCLUSION : Primary health care nurses may encourage trusting relationships by making cultural adjustments and increasing cultural competency, which may increase early antenatal booking, reduce the use of harmful interventions and improve positive perinatal outcomes. CONTRIBUTIONS : This study contributed to an awareness of cultural inertia among PHC nurses, which may be averting clients from openness to health promotion provided at PHC facilities.