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Design of an automated cyanide gas detection and control system for a gold mine
Get PDFConference Contribution, North-West University, Potchefstroom,Cyanidation is an essential process that uses sodium cyanide in gold production. The use of sodium cyanide poses the risk of cyanide gas (HCN gas) poisoning, which has been a challenge in gold mines for many years. A gap exists in the literature regarding systems that simultaneously detect and control dangerous levels of HCN gas. Significant literature sources report HCN gas monitoring systems that detect and record gas concentration levels in the air at different intervals. Furthermore, most reported treatment methods focus on controlling free cyanide in processing effluent, not the HCN gas. Therefore, this paper presents the design of an automated, real-time HCN gas detection and control system for a gold mine using the Internet of Things (IoT). The designed system can detect any rise above the OSHA legal airborne HCN gas permissible exposure limit (PEL) of ten parts per million. In case of detection, the sensor sends a signal to the microcontroller, which triggers a warning alarm to alert workers to evacuate the area. Simultaneously, a signal is sent to the solenoid valve to close the cyanide tank supply. The DC fan immediately provides an air supply that neutralizes the toxic levels of HCN gas
The ‘Justice’ in ‘Just and Equitable’ Compensation
No full textBook chapter,This chapter investigates the notion of ‘justice’ that informs ‘just and equitable’ compensation in section 25 of the Constitution and questions whether this notion changed during the attempt to amend section 25. It starts off by investigating the possible meaning of ‘justice’ during the transition and interrogates the usefulness of that notion of justice in interpreting section 25. It makes the argument that the conversations bringing about the Constitution Eighteenth Amendment Bill, even though not leading to an amendment, were important to challenge the notion of ‘justice’. The adoption of this Constitution lays a secure foundation for the people of South Africa to transcend the divisions and strife of the past, which generated gross violations of human rights, the transgression of humanitarian principles in violent conflicts and a legacy of hatred, fear, guilt and revenge. These can now be addressed on the basis that there is a need for understanding but not for vengeance, a need for reparation but not for retaliation, a need for ubuntu but not for victimisation (Epilogue of the interim Constitution, 1993)
A comprehensive high pure momentum equity timing framework using the Kalman filter and ARIMA forecasting
Get PDFArticle, Faculty of Natural and Agricultural Sciences (Unit for Data Science and Computing (UDSC)--Northwest University, Potchefstroom CampusThe pursuit of higher returns has led to a growing interest in factor timing as a strategy to enhance portfolio returns. Momentum is a popular factor, which involves buying securities that have shown consistent price appreciation over the past 3 to 12 months or past few years, with the expectation that the trend will continue and reducing exposure to those that consistently declined. An important part of a factor timing strategy is in the portfolio optimization process. This article aimed to first construct a large capitalization pure momentum portfolio, which included a dynamic stringent portfolio construction process criteria for selecting stocks estimated from historical data. Second, as a part of the portfolio’s risk management strategy, the Kalman filter was applied to the historical performance of this portfolio. Lastly, the ARIMA forecast was used to estimate expected performance and the confidence intervals. The empirical results showed that this pure equity momentum factor timing framework with the Kalman filter together with the ARIMA (autoregressive integrated moving average) forecasting methodology was iterative and incorporated new information as it became available and further enhanced the monitoring and rebalancing process. This adaptive approach enabled the portfolio to capitalize on time-varying return anomalies as they occured
Attenuating the relationship between job insecurity and job satisfaction: An examination of the role of organizational learning climate in three countries.
Get PDFJournal Article. Faculty of Humanities: Research & Innovation, North-West University, Vaal campusResearch indicates job insecurity (JI) is related to lower job satisfaction, partially mediated by psychological contract breach (PCB; a perceived breaking of the implicit exchange relationship between employer and employee). The authors investigated the extent to which providing a positive organizational learning climate (OLC) might attenuate the relationships between (a) qualitative JI and PCB and (b) PCB and job satisfaction. Using cross-sectional survey data from higher education industry employees within the US (N = 372), South Africa (N = 1096), and Croatia (N = 719), the study found consistent results across all three settings. Qualitative JI was negatively associated with job satisfaction both directly and indirectly via PCB. Although a positive OLC did not attenuate the relationship between JI and PCB, it did buffer the relationship between PCB and job satisfaction. The findings are discussed in light of Conservation of Resources theory and the need to identify practical organizational interventions to alleviate the adverse effects of qualitative JI.This research was made possible by the Knowledge Interchange and Collaboration (KIC) grant of the National Research Foundation (South Africa) under the grant number 110267 (Reference number KIC170419227844) and through funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement no. 896341
Blurring the binaries of home/school in Family Language Policy: Parents as teachers in heritage language lessons
Get PDFJournal Article. North-West UniversityThe persistence of the COVID-19-induced lockdowns resulted in increased parent-child encounters as parents worked from home while children learnt through remote platforms. This blurred the binaries of home/school as parents assumed the role of teachers by participating in children’s schooling more formally. By focusing on the role of parents as teachers in heritage language tasks, this study discusses family language ideologies and how they are infused into the teaching and learning of Ndebele, a historically minoritised and marginalised language in Zimbabwe. Data is drawn from a linguistic ethnography of a Ndebele heritage language family residing in the city of Bulawayo. Data consists of audiorecorded Ndebele language lessons and parental interviews. By drawing on the concepts of Family Language Policy and Bourdieu’s notion of ‘legitimate language’, the study exposes how children’s heritage language tasks became important aspects of family’s language transactions, contestations and negotiations. Parents build on their temporary teacher authority to assert their agency in reinforcing a Ndebele identity by endeavouring to teach Ndebele to their children through a ‘Ndebele lens’. Children’s stances towards parents’ monolingual practices and ideologies reveal their resistant agency. Their appeals for explanations and translations of some Ndebele words and expressions into English reproduce school language practices and ideologies that project English as the legitimate language. Parents’ insistence on monolingual practices and children’s language negotiations also reproduces the tensions that exist between English and indigenous languages at school and in the community at large. The study concludes that despite these tensions, these heritage language tasks present opportunities for productive language concordant parent-child encounters that reinforce children’s linguistic identities
Experimental and Computational Thermal Analysis of Ti-Based Alloy Produced by Laser Metal Deposition Technique
Get PDFArticle, Faculty of Natural and Agricultural Sciences (Material Science Innovation and Modelling (MaSIM)--Mahikeng CampusA Ti-Fe-Si-Cr-Nb alloy was fabricated using laser metal deposition (LMD) technique. The laser power and scanning speed were varied during fabrication to optimize the processing parameters. The thermal behavior during LMD processing was modeled and simulated by means of COMSOL Multiphysics 6.0 software. The samples produced were characterized using an optical microscope, X-ray diffractometer, and scanning electron microscope coupled with energy dispersive spectroscopy. The microhardness and wear behavior of the alloy were tested using a diamond indenter and ball-on-disk wear machine. The results obtained showed that the alloys exhibited similar dendritic microstructure for all processing parameters. The formation of cracks and pores were evident mainly in samples that were produced at high scanning speed and low laser power. A decrease in microhardness was noticed when the
laser power was increased, while an increase in scanning speed yielded samples with high microhardness values. The alloy showed good tribological behavior, but no clear relationship between the wear resistance of the alloy and the variation of the laser processing parameters could be establishe
Genomic characterisation of an extendedspectrum β-Lactamase-producing Klebsiella pneumoniae isolate assigned to a novel sequence type (6914)
Get PDFJournal Article, Faculty of Natural and Agricultural Sciences, Unit for Environmental Sciences and Management-- Potchefstroom CampusBackground: Cow milk, which is sometimes consumed raw, hosts a plethora of microorganisms, some of which are beneficial, while others raise food safety concerns. In this study, the draft genome of an extended-spectrum β-lactamase-producing Klebsiella pneumoniae subsp. pneumoniae strain Cow102, isolated from raw cow milk used to produce traditional foods in Nigeria, is reported.
Result: The genome has a total length of 5,359,907 bp, with 70 contigs and a GC content of 57.35%. A total of 5,244 protein coding sequences were detected with 31% mapped to a subsystem, and genes coding for amino acids and derivatives being the most prevalent. Multilocus sequence typing revealed that the strain had new allelic profile assigned to the novel 6914 sequence type possessing capsular and lipopolysaccharide antigen K locus 122 with an unknown K type (KL122) and O locus O1/O2v2 with type O2afg, respectively. A total of 28 resistance-related genes, 98 virulence-related genes, two plasmids and five phages were identified in the genome. The resistance genes oqxA, oqxB and an IS3 belonging to cluster 204 were traced to bacteriophage Escher 500,465. Comparative analysis predicted one strain specific orthologous group comprising three genes.
Conclusion: This report of a novel sequence type (ST6914) in K. pneumoniae presents a new allelic profile, indicating ongoing evolution and diversification within the species. Its uniqueness suggests it may represent a locally evolved lineage, although further sampling would be necessary to confirm this hypothesis. The strain's multidrug resistance, virulence gene repertoire, and isolation from animal milk render it a potentially significant public health concern, underscoring the importance of genomic surveillance in non-clinical settings to detect emerging strains. Further research is required to fully characterise the capsular K type of ST6914.Acknowledgements
The authors are thankful to the animal breeders in dairy farms where milk samples were collected in Sokoto State, Nigeria for assistance during the milking process.
Funding
This study was partly funded by the Applied Microbiology International (formerly: Society for Applied Microbiology), United Kingdom, through the 2019 Research Support Grant awarded to MOA and CNE. Open access funding provided by North-West University
Strategic Spatial Planning for Air Quality: Evaluating Policies in South African Urban Development
No full textConference Contribution, Faculty of Natural and Agricultural Sciences (Unit for Environmental Sciences and Management)--Northwest University, Potchefstroom CampusThe integration of spatial planning and air quality management is essential for sustainable urban development and is, expectedly, strongly advocated in the Municipal Systems Act (32 of 2000). Rapid urbanisation and industrialisation in South Africa induced air quality challenges, particularly affecting low-income settlements near heavy industrial zones. This literature review aims to critically analyse the alignment between South African spatial planning and air quality management directives. By examining key directives (policies, frameworks and legislation), this study investigates whether these directives are aligned to mitigate air pollution and promote equitable urban development. The findings highlight gaps and synergies in directive implementation, providing insights into the effectiveness of current directives to intercept rapidly decreasing air quality. Ultimately, this review underscores the need for improved and aligned directives that address urban planning and air quality management to facilitate healthier living environments for all South Africans
Transactivator of Transcription (Tat)‑Induced Neuroinflammation as a Key Pathway in Neuronal Dysfunction: A Scoping Review
Get PDFJournal Article, Human Metabolomics, North-West University, PotchefstroomThe activity of HIV-1 and its viral proteins within the central nervous system (CNS) is responsible for a wide array of neuropathological effects, resulting in a spectrum of neurocognitive deficits defined as HIV-associated neurocognitive disorders (HAND). Amongst the various viral proteins, the transactivator of transcription (Tat) remains detectable even with effective antiretroviral therapy (ART) and suppressed viremia, highlighting the significance of this protein in the modern ART era. Tat has been extensively researched in both fundamental and clinical settings due to its role in neuroinflammation, neuronal damage, and neurocognitive impairment amongst people living with HIV (PLHIV). To date, numerous fundamental studies have explored Tat-induced neuroinflammation. However, there is no clear consensus on the most frequently studied inflammatory markers or the consistency in the levels of these Tat-induced inflammatory marker levels across different studies. Therefore, we conducted a scoping review of studies investigating Tat-induced neuroinflammation. We conducted searches in PubMed, Scopus, and Web of Science databases using a search protocol tailored specifically to adhere to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses for scoping reviews (PRISMA-ScR) guidelines. From the 22 included studies, findings suggest that the HIV-1 Tat protein amplifies levels of neuroinflammatory markers. Amongst the vast array of inflammatory markers explored in the included studies, consistent results point to higher levels of CCL2, IL-6, IL-8, and TNF-α in primary cells and cell lines exposed to or transfected with HIV-1 Tat. These markers are regulated by key inflammatory pathways, such as the extracellular signal-regulated kinase (ERK)1/2 mitogen-activated protein kinase (MAPK) pathway, the phosphatidylinositol 3-kinase (PI3K) pathway, the p38 MAPK pathway, and nuclear factor-kB (NF-kB). Furthermore, Tat has been shown to induce neuronal apoptosis, both directly and indirectly. With regards to study designs, utilizing full-length Tat101 at concentrations ranging from 100 to 1000 ng/ml and durations of 24 and 48 h appears optimal for investigating Tat-induced neuroinflammation. In this context, we highlight specific inflammatory markers and pathways that are potentially pivotal in Tat-induced neuroinflammation and subsequent neuronal damage. A deeper investigation into these markers and pathways is crucial to better understand their roles in the development of HAND.Open access funding provided by North-West University. MEW was funded by the NRF Thuthuka grant (TTK22031652) and the Poliomyelitis Research Foundation (PRF) grant (23/84)
Suitability of invasive gobies as paratenic hosts for acanthocephalans of the genus Pomphorhynchus sp.
Get PDFJournal Article, Water Research Group, Unit for Environmental Sciences and Management, North-West University, PotchefstroomPonto-Caspian gobies became highly abundant in many regions outside their native distribution range (e.g. in the Rhine River system). In the newly invaded habitats, the parasite communities of the invasive gobies are characterized by a lower species richness compared to their native range. Interestingly, acanthocephalans of the genus Pomphorhynchus are highly abundant, although they do not become mature and mostly remain encapsulated in the abdominal cavity as preadults. Thus, gobiids could either represent a dead-end host for Pomphorhynchus sp. declining its population (dilution effect) or act as a paratenic host that could increase the infection pressure if the infected gobies are preyed upon by appropriate definitive hosts (spill back). To determine which of the 2 scenarios the gobiids contribute to, we conducted 2 infection experiments using smaller and larger individuals of the definitive host chub (Squalius cephalus), infected with preadults of Pomphorhynchus sp. collected from the abdominal cavity of Neogobius melanostomus. The results showed that preadults were able to complete their development and mature in the definitive host with mean recovery rates of 17.9% in smaller and 27.0% in larger chubs. Successful infections were observed in 62.0% and 80.0% of the smaller and larger chubs, respectively. Our study demonstrated that gobies can theoretically serve as a paratenic host for acanthocephalans of the genus Pomphorhynchus, and that infection might spill back into the local fish community if infected gobies are preyed upon by suitable definitive hosts of Pomphorhynchus sp. such as large barbel or chub