16918 research outputs found
Sort by
Recovery of organic electrolyte solvents from spent perforated Li-ion cells using a low-temperature vacuum-assisted distillation process
No full textElectrolyte solvent recovery is rarely addressed in current state-of-the-art lithium-ion battery (LiB) recycling processes, even though electrolytes are flammable, toxic, and hazardous. In conventional recycling processes, electrolytes typically evaporate or decompose uncontrollably during pre-treatment steps such as shredding, leading to both safety risks and environmental damage. To overcome these limitations, we investigated a controlled electrolyte solvent recovery process using mild-temperature vacuum distillation on perforated, intact batteries rather than shredded material. This method enabled safe handling and minimised uncontrolled emissions during pre-treatment. Analysis results demonstrate a successful 84 % recovery of the major electrolyte solvents, dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and ethylene carbonate (EC), after 300 min of thermal-vacuum treatment at 110 °C and 80 mBar vacuum pressure. Decomposition products of Lithium Hexafluorophosphate (LiPF₆), which include hydrogen fluoride (HF) and phosphoryl fluoride (POF₃), were not identified in the exhaust gas, and the scrubber solution remained neutral during operation. These results demonstrate that thermal treatment below 110 °C is a non-complex, feasible, and environmentally friendly process for recovering electrolyte solvents prior to metal recovery, addressing a major gap in current LiB recycling processes
Women’s experiences of communication and supportive care during labour: a qualitative study in rural KwaZulu-Natal, South Africa
No full textBackground: Quality maternal care is crucial to improve outcomes for both mothers and newborns. Many initiatives to improve maternal care concentrate on improving clinical practice. However, women’s experiences of care are also important determinants of health outcomes. Establishing strong interpersonal relationships between health workers and women is essential for delivering high-quality person-centered care, with health workers who empathize with women, respect their needs and concerns, and communicate effectively. Aligned with the World Health Organization standards of care framework, this study aimed to explore women’s experiences of care during labour and childbirth, focusing on communication, respectful, and supportive care. Methods: A qualitative exploratory study was conducted with postpartum women in rural district hospitals in KwaZulu-Natal. Purposive sampling was used to recruit women from communities within the hospitals’ catchment areas. Data were collected through focus group discussions (FGDs) conducted in the local language of participants. Five FGDs were conducted between January and April 2023. Inductive thematic analysis using NVivo v12 was employed to analyze the data. Findings: A few women described positive experiences of care, but most women reported suboptimal care characterized by poor communication, lack of privacy, and disrespectful treatment. Participants described experiences of verbal and physical abuse, being called demeaning names, facing invasive procedures without providing consent, and inadequate emotional support, such as their concerns being systematically ignored and birth companions being denied entry to labour wards. Some women responded to these challenges through various coping mechanisms including staying quiet to avoid confrontation, following instructions rigidly, seeking advice from other women in the labour ward, and in some cases standing up for themselves. Some women described persistent anger and distress as a result of their experiences. Conclusion: The findings of the study highlight persistent gaps in effective communication and supportive care for women during labour and childbirth. Possible interventions could be aimed at improving communication skills of health workers as well as fostering a culture of empathy and respect for women in their care. In addition, empowering women through antenatal education and implementing birth companion policies could further improve women’s experiences during labour and childbirth
A Research Paper submitted in partial fulfilment of the requirements for the degree of master in ducation (adult learning and global change)
No full textThis study investigated the impact of a shift in the medium of instruction from face-to-face to online learning on the identity formation of students at Technical and Vocational Education and Training (TVET) colleges. Drawing on a Foucauldian lens, the study critically analyses and problematises the shift in power relations that students and teachers encounter in online teaching and learning environments. The main themes explored in this study were the conceptions of e-learning, autonomy and challenges in e-learning, online identity in e-learning, and students’ and lecturers’ shifts of power relations. The study employed a qualitative research approach, gathering data through semi-structured interviews at a TVET college in South Africa. The investigation explored how the shift to online learning has resulted in changes in students’ identities, particularly in relation to how identity shifts due to moving to an online teaching and learning platform. The study examined how students and lecturers negotiate and resist the exercise of power in online learning environments and how their identities are shaped and reshaped in response to these power dynamics The findings of this study contribute to an understanding of the complex interplay between identity formation, power relations, and online learning in the context of TVET colleges. This research has implications for policymakers, educators, and researchers interested in understanding the multifaceted nature of student identity in the digital age. As such, the study provided insights into the challenges and opportunities that students encounter in online learning environments and suggests recommendations for educational institutions to create inclusive and empowering online learning experiences for students
Using machine learning algorithms to develop a remotely-sensed framework for drought monitoring in different climate regions in South Africa
No full textDroughts pose a significant threat to rainfed smallholder farming systems, particularly in regions with varying climatic conditions. This study aimed to develop a spatial modelling framework for assessing the occurrence and frequency of droughts across different climatic zones, with a focus on rainfed smallholder farms. Specifically, this study sought to develop a spatial modelling framework for assessing the occurrence and frequency of droughts on rainfed smallholder farms across different climatic zones in South Africa i.e. the Limpopo, North West, Mpumalanga and Gauteng Provinces. By integrating satellite-derived vegetation indices, specifically the Normalised Difference Vegetation Index (NDVI) and the Modified Soil-Adjusted Vegetation Index 2 (MSAVI2), with state-of-the-art machine learning algorithms, the accuracy of drought mapping in rainfed smallholder farms was significantly enhanced. The study employed the Gradient Boosting Decision Tree (GBDT), Support Vector Machine (SVM), Convolutional Neural Network (CNN), Random Forest (RF) and Transformer models to capture complex spatial and temporal patterns of drought dynamics. The results showed that the Transformer model was effective in detecting rainfed smallholder farms (with an Overall Accuracy of 0.85 and a mean Intersection over Union (IoU) of 0.86). The study further evaluated the agricultural and meteorological drought conditions from 2004 to 2023. The Vegetation Condition Index (VCI) from SPOT VEGETATION 1 and PROBA-V data and the Standardised Precipitation Index (SPI) from CHIRPS data were computed
Impact of thyroid dysfunction on clinical outcome in head and neck cancer: a systematic review and meta-analysis
No full textBackground: The influence of thyroid dysfunction on the clinical outcomes of head and neck cancer (HNC) patients remains an area of ongoing investigation, with previous studies yielding variable results. Treatments for HNC, particularly radiotherapy, frequently impact thyroid function. This meta-analysis aimed to synthesize the available evidence on the association between thyroid status (dysfunction vs. euthyroid) and survival outcomes in HNC patients. Methods: A systematic review and meta-analysis were conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Medline, Web of Science, Cochrane Library, Embase and Scopus were searched (January 2000-October 2024) for studies comparing survival outcomes (primarily Overall Survival) in adult HNC patients with thyroid dysfunction versus euthyroid patients. Two reviewers independently selected studies and extracted relevant data. The risk of bias for included studies was assessed using the Newcastle-Ottawa Scale (NOS) for cohort studies and the Cochrane Risk of Bias 2 (RoB2) tool for randomized controlled trials. Hazard ratios (HRs) with 95% confidence intervals (CIs) comparing survival were pooled using both fixed-effect (common-effect) and random-effects (REML) models. Heterogeneity across studies was assessed using the I² statistic and Cochran’s Q test. Statistical analyses were performed using R with the meta package. Results: Six studies met the inclusion criteria for systematic review. Four of these studies, encompassing 671 participants, reported sufficient data (Hazard Ratios for Overall Survival) for meta-analysis. The fixed-effect model yielded a pooled HR of 0.99 (95% CI: 0.98, 1.00; p = 0.0013). However, significant heterogeneity was observed (I² = 81.5%, p = 0.0010). Consequently, the random-effects model, deemed more appropriate, yielded a pooled HR of 1.45 (95% CI: 0.66, 3.19; p = 0.3601), indicating no statistically significant association between thyroid status and overall survival in HNC patients. The estimated between-study variance (τ²) was 0.53. Conclusion: This meta-analysis revealed substantial heterogeneity among studies investigating the impact of thyroid status on HNC survival. When accounting for this heterogeneity using a random-effects model, no significant association was found. The findings highlight the need for further research with larger sample sizes, standardized definitions of thyroid dysfunction, consistent reporting of adjusted effect estimates, and exploration of heterogeneity sources. Trial registration: CRD42024535167
Pathways, pressure, and profit: adaptive innovation and strain in a convicted cybercrime academy called Hustle Kingdom
No full textThis research offers the first empirical examination of the “Hustle Kingdom (HK)”phenomenon. Hustle Kingdoms are underground cybercrime training centers in West Africa that recruit and train young men to become digital fraudsters. The empirical foundation of this study draws on case files from the Economic and Financial Crimes Commission (EFCC) concerning the prosecution and eventual conviction of the proprietor and students of a Hustle Kingdom. Ethnographic field notes and informal conversations with relevant authorities supplement this dataset. It examines the significance of Merton’s Strain Theory ,focusing on the innovation mode of adaptation, to understand how economic pressures and socio-fabric elements of society drive individuals toward illicit entrepreneurship. Our findings reveal key characteristics of these academies ,including their structure, recruitment and governance strategies, motivations ,indirect enablers, and prosecutorial challenges. While this pioneering investigation positions Hustle Kingdoms as an alternative route to economic mobility for many youths, it situates Hustle Kingdoms within broader processes of deviant innovation and informal economic adaptation. The study concludes by reflecting on the broader ecosystem of subtle enablers
UWC carnival
No full textA collection of digitised photographs of a carnival held at the University of the Western Cape campus in the city of Bellville South Africa. As yet the precise date of the carnival is unknown. The print collection is held at the Special Collections section of the Main University Library
Local perspectives, regional consequences: the socio-environmental impacts of sand harvesting in southern Africa
No full textAfter water, sand is the most exploited resource on Earth, with extraction rates often exceeding the sustainable supply, impacting ecosystems and local communities. Still, there is very little information on the situation in southern Africa, despite the rapid economic growth in the region and associated increase in sand demand. This study aimed to address this gap by identifying the implications of sand extraction on local communities and the ecosystem, drawing upon the perspectives of local stakeholders. Qualitative data collected in Botswana, South Africa and Mozambique through stakeholder interviews, revealed a suite of environmental and social issues surrounding both licensed and unlicensed operations. The experienced negative impacts and benefits were occasionally contradictory in nature, strongly depending on characteristics relating to geography, and the type of sand harvesting activity. We subsequently explored links between experienced benefits, impacts and current regulatory frameworks through development of a Driver-Pressure-State-Impact-Response (DPSIR) framework, which highlighted that careful mining site selection and adherence to regulations could minimise socio-environmental impacts whilst achieving benefits. The findings of the study provided insights on the main obstacles for alleviating sand harvesting-related impacts and existing knowledge gaps that need to be first addressed to inform the development of more sustainable sand harvesting practices
Advanced computational techniques for pipe burst detection and localisation in water distribution networks
No full textPipe bursts cause a considerable loss of treated water, increase the risks of environmental contamination and are a health hazard for the end-user as they can create a passage for contaminants to enter water distribution networks (WDN). Identifying pipe burst locations will help water service providers repair pipe bursts in a timely manner. Given the ever-increasing importance of water, a great number of methods to locate pipe bursts have been proposed. But none have proved to produce results accurate enough for water service providers to heavily rely on. Therefore, this thesis presents a comprehensive investigation addressing two critical challenges in pipe burst localisation: optimising fully-linear deep learning (FL-DL) architectures for accurate detection and developing real-time localisation methods using Change point detection (CPD) algorithms. The research is structured in two main phases to tackle these challenges. The first phase conducts a comparative analysis of hyperparameter optimisation techniques, Particle Swarm Optimisation (PSO) and Population-Based Training (PBT), for FL-DL architectures. This investigation addresses the limitations of traditional detection methods, which are often costly, labour-intensive, and limited in scalability. Results demonstrate PSO’s superior performance, with PSO-optimised models consistently achieving higher accuracy and lower variance compared to PBT implementations. Notably, PSOFL-ResNet achieved a mean accuracy of 98.92% and PSOFL- DenseNet reached 98.78%, significantly outperforming their PBT counterparts at 96.70% and 97.22% respectively
A measurement of Galactic synchrotron emission using MWA drift scan observations
No full textStudying the diffuse Galactic synchrotron emission (hereafter, DGSE) at arc-minute angular scale is important to remove the foregrounds for the cosmological 21-cm observations. Statistical measurements of the large-scale DGSE can also be used to constrain the magnetic field and the cosmic ray electron density of our Galaxy's interstellar medium (ISM). Here, we have used the Murchison Widefield Array (MWA) drift scan observations atto measure the angular power spectrumof the DGSE of a region of the sky from right ascension (RA)toat the fixed declination . In this RA range, we have chosen 24 pointing centers (PCs), for which we have removed all the bright point sources above , and applied the Tapered Gridded Estimator (TGE) on residual data to estimate the . We use the angular multipole rangeto fit the data with a model, , where we interpret the model as the combination of a power lawnature of the DGSE and a constant part due to the Poisson fluctuations of the residual point sources. We are able to fit the modelfor six PCs centered atand . We run the Markov Chain Monte Carlo (MCMC) ensemble sampler to get the best-fit values of the parametersandfor these PCs. We see that the values ofvary in the rangetomK , whereas thevaries in the rangeto . We find that the value ofis consistent atlevel with the earlier measurement of the DGSE at similar frequency and angular scale