UWCScholar
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Doping of iron transition metal onto cerium oxide lattice for enhanced photocatalytic degradation of acid violet 7 azo dye under solar irradiation
(Elsevier B.V., 2025) Mishra, Ajay Kumar; Malatjie, Kgolofelo; Ndlovu, Lloyd
Dye-contaminated water possess a severe environmental problem due to its adverse effects on ecosystems, human health, and water resources. In this study, cerium oxide (CeO2) was successfully produced and doped with different ratios of iron (5,10 and 15 mol%) via a facile co-precipitation method for use in photocatalytic degradation of acid violet 7 (AV7) from an aqueous solution. The physicochemical properties of the nanophotocatalysts were studied using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Ultraviolet–Visible spectrophotometer (UV–Vis), Raman spectroscopy, photoluminescence spectroscopy (PL), X-ray photoelectron spectroscopy (XPS), X-ray diffractometer (XRD), and Brunauer-Emmett-Teller (BET). SEM-EDS confirmed the presence of Fe, O and Ce elements in the photocatalysts. The 5 mol% Fe-dopped CeO2 possess high photocatalytic activity with the removal efficiency of approximately 98 % of AV7 dye when compared to pristine CeO2 (38 %), 10 % Fe-doped CeO2 (85 %) and 15 % Fe-doped (86 %). The higher photodegradation of 5 mol% Fe-doped CeO2 was attributed to suppressed recombination of photogenerated charge carriers as displayed by PL, as well as the high surface area observed from BET analysis. In addition, the electrochemical characterization confirmed high migration of photogenerated electron-hole pairs for 5 mol% Fe-CeO2/FTO which substantiates the enhanced photocatalytic degradation of AV7.
The impact of intergrating the history of science into the teaching and learning of life sciences in the further education and training curriculum.
(University of the Western Cape, 2024) Buthelezi, Penelope Zamashenge Gugulethu; Langenhoven, Keith; De Beer, Josef; Khuzwayo, Bhekumusa
This study examined the impact of incorporating the History of Science (HoS) into the teaching and learning of Life Sciences in the FET curriculum. A sample of ten (10) Grade 11 Life Sciences teacher respondents from 2 (two) public secondary schools were chosen at random for the study's qualitative component. These schools were drawn from sixteen public schools in the Thabo-Mofutsanyane district, in the Free State Province of South Africa. A selected sample of fifty (50) Grade 11 learners was further drawn from these 2 (two) selected schools for the quantitative part of the study. The study developed History of Science Integrated Instruction (HoSII) experimental unit model as a teaching strategy and assessment tools. The study employed a sequential exploratory mixed methodological research design, where qualitative and quantitative data were collected sequentially. Qualitative data was collected through open-ended questionnaires and was analyzed a week prior to the implementation of the treatment. This served to inform the implementation of the HoSII experimental unit model. Quantitative data from learners was collected by one test instrument that was administered at varying periods, a preliminary test first, a day before the treatment, and as a post-test immediately after the intervention. The learners’ scores obtained from pre and post-tests were analysed using SPSS statistical analysis. The study findings indicated that historically based instruction impacted on Grade 11 learners’ educational achievement. The study advocated the necessity of teachers' in-service training, as well as curriculum adjustments to accommodate programmes perceived to be lengthy for teachers to include in their methods of instruction. The study's conclusions have ramifications for the HoSII programme which could be used to guide teachers in the integration of HoS into Life Sciences teaching. This programme would further contribute to the efforts of curriculum planners to improve Life Sciences teachers’ PCK on the integration of HoS in their teaching practices.
Finding radio transients with anomaly detection and active learning based on volunteer classifications
(Oxford University Press, 2025) Lochner, Michelle; Andersson, Alex; Woudt, Patrick
In this work, we explore the applicability of unsupervised machine learning algorithms to finding radio transients. Facilities such as the Square Kilometre Array (SKA) will provide huge volumes of data in which to detect rare transients; the challenge for astronomers is how to find them. We demonstrate the effectiveness of anomaly detection algorithms using 1.3 GHz light curves from the SKA precursor MeerKAT. We make use of three sets of descriptive parameters ('feature sets') as applied to two anomaly detection techniques in the astronomaly package and analyse our performance by comparison with citizen science labels on the same data set. Using transients found by volunteers as our ground truth, we demonstrate that anomaly detection techniques can recall over half of the radio transients in the 10 per cent of the data with the highest anomaly scores. We find that the choice of anomaly detection algorithm makes a minor difference, but that feature set choice is crucial, especially when considering available resources for human inspection and/or follow-up. Active learning, where human labels are given for just 2 per cent of the data, improves recall by up to 20 percentage points, depending on the combination of features and model used. The best-performing results produce a factor of 5 times fewer sources requiring vetting by experts. This is the first effort to apply anomaly detection techniques to finding radio transients and shows great promise for application to other data sets, and as a real-Time transient detection system for upcoming large surveys.
Leveraging remote sensing for optimised national scale agricultural water management in South Africa
(Elsevier B.V., 2025) Sibanda, Mbulisi; Mpakairi, Kudzai; Dube, Timothy
Agriculture remains a critical water resources consumer in arid regions, globally, including southern Africa. The intensity of consumption, however, varies significantly depending on the adopted watering method (i.e., rainfed or irrigated) and agricultural region. Efficient agricultural water management hinges on effectively monitoring Crop Water Use (CWU) and Crop Water Productivity (CWP). This study, thus, leveraged Moderate Resolution Imaging Spectroradiometer (MODIS) remotely sensed data in estimating the spatio-temporal variations of CWP and CWU across irrigated and rainfed croplands in diverse South African agricultural regions between 2017 and 2022. The results showed that rainfed croplands had higher CWU in agricultural regions dominated by grains (150 mm/yr) and cattle (160 mm/yr), while irrigated croplands exhibited the highest CWU in agricultural regions with sheep rearing (175 mm/yr) and subsistence agricultural activities (160 mm/yr). However, there were no significant differences (p > 0.05) in overall CWU across all the agricultural regions. Irrigated croplands generally had higher annual CWP (>0.002 kg/mm3/yr), while rainfed croplands consistently showed low CWP especially in forestry (0.001 kg/mm3/yr) and sugar (0.0012 kg/mm3/yr) agricultural regions. There were also no significant differences in average CWP between irrigated and rainfed croplands (p > 0.05). This study demonstrates the effectiveness of national-scale remotely sensed data in monitoring the spatiotemporal variations of CWP and CWU in South Africa. The results can be used to tailor strategies to specific agricultural regions and crop types and optimise water use efficiency. This would contribute significantly to sustainable national-scale agricultural water management in South Africa.
Factors shaping Covid-19 vaccine acceptability among young people in South Africa and Nigeria: an exploratory qualitative study
(Public Library of Science, 2025) Casale, Marisa; Somefun, Oluwaseyi; Sumankuuro, Joshua
Covid-19 vaccine hesitancy among young people can be seen as an acute – but not isolated – phenomenon within an alarming longer-term trend of broader vaccine distrust in Africa. Yet there are still considerable knowledge gaps in relation to the scope and drivers of low vaccine acceptability among young people. Moreover, better frameworks and tools are needed to conceptualise and better understand acceptability in this population group. We applied the recently published Accelerate Framework for Young People’s Acceptability to guide qualitative research with young people living in South Africa and Nigeria. We aimed to investigate their overall acceptability of the Covid-19 vaccine, and explore factors shaping this acceptability and willingness to be vaccinated. In collaboration with seven community-based organisation partners, we conducted 12 in-person focus groups and 36 remote interviews with 163 individuals aged 15-24. Through a collaborative, iterative process we conducted thematic analysis, incorporating aspects of both deductive and inductive approaches. Our findings show how vaccine acceptability is shaped by a multiplicity of inter-related factors. They also provide a more in-depth perspective of some of these phenomena, their relative importance and their connections in this group of young people. Limited vaccine understanding, conflicting information and distrust, the influence of others, and fear of side effects were key inter-related drivers of low vaccine acceptability. Factors promoting Covid-19 vaccine acceptability were instead: positive perceptions of vaccine safety and efficacy, protection from disease, protection of others, and a desire to return to normal activity. We discuss implications of these findings for policy and practice, both to increase acceptability of Covid-19 vaccination among young people, and more broadly promote vaccination as a critical component of public health programs. Lastly, we reflect on this first application of theAccelerate Framework, and implications for its use in future studies.