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Quantifying the cost of load curtailment on mine dewatering systems
Get PDFMaster Engineering in Mechanical Engineering ,North-West University, Potchtfsroom CampusSouth Africa is experiencing severe electricity supply shortages, leading to rolling blackouts and soaring electricity prices. In response, demand-side management (DSM) measures are crucial to ensure grid stability and to alleviate electricity costs. Alongside load shedding, mandatory load curtailment by key consumers is being enforced during critical periods to alleviate the strain on electricity supply. As a result, mining operations have been significantly impacted by the enforced load curtailment measures.
Mine dewatering systems have long been considered suitable for DSM measures, with load shift away from peak time-of-use easily implemented due to the built-in water storage capacity in the systems. Additionally, pumping systems have been halted for prolonged periods as part of load reduction strategies for Eskom's load curtailment, intensifying the strain on mine dewatering systems. It is, therefore, challenging to find a balance between load reduction, meeting dewatering requirements, and maintaining load shift.
A lack of information regarding the cost of load curtailment on mine dewatering systems presents a significant challenge in devising clear strategies for load reduction and comparing alternative load reduction approaches. Currently, there is no existing model that relates the incidence and duration of load curtailment events to the electricity cost of mine dewatering operations, necessitating an in-depth investigation.
This study aims to quantify the cost of load curtailment on the mine dewatering systems. A method was developed to assess the cost implications under various load curtailment scenarios at mine dewatering systems, involving the creation of a digital twin simulation model of the dewatering system.
The method was implemented at a case-study mine shaft A, located at mining operation 1. The simulation was adjusted iteratively to examine the relationship between load curtailment duration and pumping electricity cost, DSM performance, and meeting dewatering requirements over a 30-day test period.
The case study simulation results revealed that pumps can be stopped for up to 135 hours a month while still meeting dewatering requirements. The cost of electricity for pumping increases with each additional instance of curtailment, totalling R5.52 million in winter and R990 thousand in summer for 135 hours of load curtailment, based on 2023/24 tariffs. Peak pumping is necessary after 32 hours of pump stoppages, and load shift performance declines after that. Nevertheless, the evening load shift project performance remains above the 6.7 MW target, as curtailment often aligns with evening peak periods.
Initiating diesel generators for load reduction costs around R80 000 per hour, totalling R11.4 million over 135 hours. Pump stoppage costs start low but peak at R90 000 per hour after 127 hours in winter. Therefore, it appears that pump stoppages represent a viable load reduction strategy at shaft A for up to 123 hours per month in winter and 135 hours in summer.
The developed method proved effective in determining the cost of load curtailment on mine dewatering systems for any given shaft. The findings of this study will help mining industries to devise more informed strategies for managing load curtailment while ensuring the efficient and cost-effective operation of their dewatering systems.-ETA Operations (Pty) LtdMaster
The influence of organisational culture on psychological safety, affective commitment, and organisational citizenship behaviour at selected SETAs in South Africa
Get PDFMasters in Business Administration, North-West University, Vanderbijlpark CampusPurpose: As organisational culture plays a pivotal role in the growth and success of any organisation, a positive and effective organisational culture can have a significant influence on employee behaviour, including psychological safety, affective commitment, and organisational citizenship behaviour (OCB). The purpose of this study is to investigate the influence of organisational culture on psychological safety, affective commitment, and OCB in selected Sector Education and Training Authorities (SETAs) in South Africa. The study examines the relationship between organisational culture, psychological safety, affective commitment, and OCB.
Design/methodology/approach: A quantitative research approach was used. Using the convenience sampling technique, quantitative data was collected via an online survey with 174 employees working in six different branches of SETA located in the Gauteng province of South Africa. Data was analysed using the Statistical Package for Social Sciences (SPSS) Version 28.0.
Results: The results of this study reveal a negative relationship between organisational culture, psychological safety, and OCB. The results further reveal a negative correlation between affective commitment and psychological safety. However, a moderate positive relationship was found between organisational culture and affective commitment.
Managerial implications/limitations: The findings of this study can be useful for policymakers and public sector organisations responsible for employee wellbeing and maximising their commitment to the organisation. This study was limited to six SETA offices in one province in South Africa, namely the Gauteng province. This study was also limited in terms of research design and methodology. This study also provides recommendations for future research.
Originality/value: The findings of this study will contribute to the body of knowledge regarding organisational culture, psychological safety, employee affective commitment, and organisational citizenship behaviour in public sector organisations.Master
The impact of COVID-19 on the relationship between sustainability and financial performance: A multi-theoretical interpretation
Get PDFMaster of Commerce in Management Accountancy, North-West University, Potchefstroom CampusMost research papers do not emphasise the importance of theoretical frameworks enough – theories are often only included for publication purposes, or briefly mentioned and never revisited, or even omitted. The focus of this study was to consider how theoretical frameworks impact the interpretation of results. The primary objective of the study was to consider the interpretation of multiple theories (six selected theories) on a specific scenario, i.e., the relationship between JSE listed companies’ financial performance (in terms of financial ratios) and sustainability performance (in terms of ESG) before and after the COVID-19 pandemic.
Literature revealed that there are inconclusive results regarding the relationship between financial and sustainability performance. Furthermore, there were limited cases where this relationship was examined within a crisis-period. The most recent crisis, the COVID-19 pandemic, had an immense impact on companies’ performance; subsequently this study investigated the relationship between companies’ financial and sustainability performance before and after COVID-19. This relationship was used as a scenario where the results obtained were interpreted within the context of multiple theoretical frameworks.
A sample of 104 JSE listed companies from the sectors that were probably most severely affected by COVID-19 was selected. Data was extracted for 2017 to 2022 to analyse the association between financial performance and sustainability performance. A mixed effect regression model was developed to test the association and to provide a basis to interpret the results within the context of multiple theories.
ROE, an accounting-based measure of financial performance, was the main indicator of financial performance. However, after correlations were conducted, Tobin’s Q, a market-based measure of financial performance, and ESG, a measure of sustainability performance, revealed the most significant relationship – therefore, the relationship between these two variables, before and after COVID-19, was considered when the results were interpreted within multiple theories.
It was concluded that sustainability performance had a negative impact on financial performance, both before and after COVID-19. In contrast, financial performance had a negative impact on sustainability performance before COVID-19, but a positive impact after COVID-19. These results were interpreted within the context of stakeholder-, stewardship-, signalling-, shareholder-, resource-based- and legitimacy theory. It was concluded that the theoretical framework from which a specific scenario is considered, impacts the interpretation of results, i.e., the same results can be seen as positive or negative, depending on the applicable theory. This illustrated the importance of theoretical frameworks.Master
Exploring the impact of the fourth industrial revolution on a ferrochrome production plant in South Africa
Get PDFMaster of Business Administration, North-West University, Vanderbijlpark CampusThe central research question of this study is, "How can the Fourth Industrial Revolution (4IR) impact a ferrochrome production plant in South Africa?" This question is particularly relevant given the increasing global focus on 4IR technologies and their potential to revolutionise industries. This is especially important for the South African ferrochrome industry, a sector crucial for the country's economy.
The study employs a mono-method, qualitative research approach, considered the most suitable due to its focus on non-numeric data collection and analysis. Semi-structured interviews were conducted with industry professionals to gain in-depth insights into their perspectives on 4IR. Eight participants from various management levels in one organisation were interviewed. The data was transcribed and analysed using coding techniques and Atlas.ti to identify key themes and patterns.
The research is structured into various sections, beginning with an introduction that outlines the problem statement, objectives, and the study's relevance in filling existing knowledge gaps. This is followed by a literature review that provides an industry overview and investigates the potential impact of 4IR on safety, profitability, and sustainability within the ferrochrome sector.
Key findings include a general familiarity with 4IR but a notable gap in practical understanding, the industry's emerging progress in 4IR adoption, and the potential for positive impacts on safety, profitability, and sustainability. The study underscores the necessity of 4IR implementation for the industry's competitiveness and sustainability, highlighting the importance of early technology adoption.
In conclusion, the study effectively addressed its primary objective by exploring the potential impact of the Fourth Industrial Revolution (4IR) on a ferrochrome production plant in South Africa. The industry's progress in 4IR is still in emerging stages. However, the potential for a positive impact on safety, profitability, and sustainability is evident. The importance of implementing 4IR technologies is emphasised by the ferrochrome sector's critical role in South Africa's economy. Given the industry's
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significance, adopting 4IR is beneficial and essential for its continued viability in South Africa.
As for the secondary objectives, the study successfully determined the industry's readiness for 4IR, explored its relevance for the future of ferrochrome production in South Africa, and drew actionable conclusions on its impact. The study also highlighted the importance of considering environmental, social, and political factors in strategic planning for 4IR. Recommendations for both practical industry applications and future research are provided, making this study a foundational piece for further investigations into the impact of 4IR on the ferrochrome industry in South Africa.Master
Novel data augmentation schemes for pose classification using a convolutional neural network
Get PDFMaster of Science in Computer Science, North-West University, Potchefstroom CampusPopulation aging is a global trend that can be attributed to declining fertility rates, longer life expectancies, and aging cohorts in many developed countries. The number of individuals over the age of 60 is expected to rise significantly in the coming decades and will likely place additional pressure on healthcare systems worldwide. Currently, falls are one of the leading causes of hospitalisation among the elderly and can result in life-threating injuries and long-term disability. Promptly administering aid to a fall victim can significantly improve their chances of recovery and reduce the need for specialised care. To address these problems, fall detection systems have been developed which facilitate early intervention and reduce the negative consequences of falls. This allows seniors to maintain their independence even after incurring a fall while also alleviating the anticipated pressures on healthcare since injuries are readily treated. However, there is no universal approach or solution to fall detection due to the complexity of the problem domain. New avenues of research are continually stimulated and explored as technological advances are made and new sensor technology becomes available.
Vision-based approaches for fall detection are more favourable than wearable and ambient sensor-based approaches since they are less obtrusive and can provide more information about the context of a fall. However, fall recognition requires quantifying the recorded human body from footage data, which can be achieved through pose estimation and approximating the location of different body parts. This study investigates the effectiveness of data augmentation techniques on such pose estimated mappings to improve pose classification when conducted using a convolutional neural network (CNN). A novel pose descriptor is designed that can be superimposed onto the imaged human body to encode the kinematic arrangement of limbs and relevant positional cues. This method emphasises the postural differences between poses in the abstracted feature space of a CNN classifier, thereby improving the classifier's ability to reliably differentiate between poses. The approach is demonstrated on a fall dataset that consists of multiple pose classes that are typical of everyday activities.
The study results indicate that the proposed visual augmentation schemes are effective in improving CNN-based pose classification. An improvement of up to 11 percentage points was achieved over a baseline pose recognition accuracy that is free of any augmentations. The simplicity of the approach makes it useful for real-time applications that warrant timely action and response. These findings are expected to pave the way for more accurate fall detection systems that minimise the risk of fall-related injuries while reducing the intensity of their medical care.Master
Examining the Oversight Role of the Republic of Botswana’s Parliament
Get PDFDoctor of Philosophy in Public Management and Governance, North-West University, Potchefstroom CampusThe study attempted to examine the oversight role and function of the Republic of Botswana Parliament. Concern regarding the role and function of Parliament in ensuring accountable Executive authority required scholarly examination. Such an examination was necessary to maintain key public administration principles of realising effective and efficient public service. The ineffective execution of the principle of separation of powers, has resulted in structural, administrative, and operational limitations that hinder the effectiveness of Botswana’s Parliament to hold the Executive accountable. Therefore, this study sought to develop a framework necessary to enhance guiding of the oversight role and function of Parliament as well as to foster the separation of powers between Parliament and the Executive branches of government in Botswana. This enhancing of the oversight role of Parliament is necessary to attain an independent, strong, efficient and effective Parliament which is able to hold the Executive meaningfully accountable. To achieve its purpose, the study used qualitative research methodologies. The first were semi-structured interviews, employed as the empirical component of the study, and allowing predetermined questions with respondents to guide the discussions. The second used a desktop review data collection approach which is highlighted throughout the study. This approach is summarised to provide a discourse and understanding of the applicable oversight framework for the Parliament of Botswana that fosters the principle of separation of powers. Participants were drawn from stakeholders relevant to this study, such as current and former members of Parliament (MPs), current and former members of the Executive, the Clerk and Speaker of the National Assembly, representatives of civil society organisations in Botswana and academic experts from the University of Botswana. Key findings of the study are that Botswana’s Parliament is limited and often ineffective in exercising its oversight responsibilities. This finding is observed owing to a number of reasons, including Parliament’s lack of independence from the Executive, the dominance and control of Parliament by the Executive, the extensive executive powers of the president, a single dominant ruling party, weak opposition parties, weak civil society organisations, insufficient support staff for MPs, the nature of the political party caucus system, lack of question time for the president, the manner in which the motion of no confidence item is structured by the Constitution of the Republic of Botswana of 1966, and undeveloped Parliamentary committee structures. The study concludes, recommending that, in order to optimise the oversight function of Parliament, and to eliminate the dominance and control of the Executive, Parliament needs to be separated from the Executive in accordance with the classical principles of the theory of separation of powers, as highlighted in the proposed oversight framework of the study. It is considered that, once Parliament is separated from Executive control, then reforms pertaining to the operational and administrative oversight challenges may be better implemented. The study recommends an overarching and comprehensive oversight framework necessary to guide the role and function of Parliament in Botswana. It is within this framework that solutions to the aforementioned administrative and operational problems identified are provided.Doctora
The influence of HIV-1 viral protein R sequence variation on immune activation, inflammation, and metabolism: implications for neurocognitive impairment
Get PDFMaster of Science in Biochemistry, North-West University, Potchefstroom CampusBackground
Human immunodeficiency virus (HIV) affects millions of people around the world and was shown
to affect the central nervous system (CNS), resulting in HIV-associated neurocognitive disorder
(HAND). Despite the use of antiretroviral therapy (ART), mild forms of HAND persist. HAND is
associated with systemic inflammation and dysregulated metabolism. Although viral proteins have
a role in HIV-1 pathogenesis and the development of HAND, the exact role of less common viral
proteins such as viral protein R (Vpr), are not known. Little is known about the influence that Vpr
amino acid sequence variants have on immune activation, inflammation, and metabolism in
people living with HIV. Here, we investigated the relationship between Vpr amino acid sequence
variants, inflammation, and metabolism in a cohort of South African people living with HIV.
Methods
A systematic review was conducted to determine the association of Vpr amino acid variants with
clinical outcomes in people living with HIV by creating a search criterion and selecting articles
based on this selection criterion. Plasma samples from n = 48 South African, subtype C people
living with HIV were used to investigate the association between Vpr amino acid sequence
variation and immune activation, inflammation, and metabolism in an antiretroviral (ART)-naïve
cohort. Viral protein sequence analysis was done to determine the presence of amino acid
variants at positions 22, 41, 45, and 55 which are associated with neurological outcomes in people
living with HIV. Enzyme-Linked Immunosorbent Assay (ELISA) analysis was performed to
measure sCD163, neutrophil gelatinase-associated lipocalin (NGAL), high-sensitivity C-reactive
protein (hsCRP), soluble urokinase plasminogen activator receptor (suPAR), and interleukin-6
(IL-6) concentrations in people living with HIV. For liquid chromatography–tandem mass
spectrometry (LC-MS/MS), plasma samples from n = 32 people living with HIV were used to
investigate the levels of tryptophan, kynurenine, kynurenic acid, quinolinic acid (QUIN), and the
tryptophan/kynurenine ratio. Various statistical analyses were conducted to determine the
association between Vpr amino acid sequence variation and the levels of immune markers and
metabolites of the tryptophan-kynurenine pathway.
Results
A systematic review of the existing literature suggested that Vpr amino acid variants are
associated with clinical outcomes such as disease progression, neurological outcomes, and
treatment status in people living with HIV. In this regard, 77H and 85P Vpr amino acid variants
were considered noteworthy. Furthermore, Vpr amino acid variants associated with negative
neurological outcomes were identified. Among the many neuropathogenic Vpr amino acid
variants and immune markers examined, the ELISA analysis revealed that after applying
Bonferroni corrections (p = .05/3) and adjusting for sex and locality, suPAR levels were nearing
significance for higher levels in participants with the 41G amino acid variant compared to those
with the 41S variant (p = .035). Further, amino acid variations at position 41 (between 41G and
41S) exhibited a significant association with suPAR (adj R2 = .089, β = .386; 95% CI .125 to 3.251;
p = .035). The metabolomics data found that, out of all the Vpr amino acid substitutions and
metabolites that were investigated, only the Vpr 41G and 55A groups was nearing significance
for higher levels of QUIN compared to the Vpr 41S and 55T groups, respectively (all p = .023)
after applying Bonferroni corrections (p = .05/3) and adjusting for covariates (age and sex).
Multiple regression results revealed that Vpr amino acid variations at position 41 (adj R2= .049, β
= .505; p = .023), and 55 (adj R2= .126, β = .444; p = .023) displayed significant associations with
QUIN after adjusting for age and sex. Lastly, the higher QUIN levels observed in the Vpr 41G
group were found to be correlated with suPAR (r = .588, p = .005).
Conclusions
These findings suggest that Vpr amino acid sequence variations might contribute to dysregulated
inflammation in people living with HIV, which could explain the observed association between
specific Vpr variants and HAND found in prior research. Furthermore, the Vpr amino acid
sequence variations could have an influence on metabolism and inflammation, potentially
contributing to HIV-1 pathogenesis and the development of HAND. Thus, these Vpr variants merit
further investigation to fully understand their roles in HIV-1 pathogenesis and neuropathogenesis.Master
User-based activity logging and analysis to improve system maintenance
Get PDFMaster of Engineering in Computer and Electronic
Engineering, North-West University, Vanderbijlpark CampusSoftware maintenance is continuous and forms part of the software development process. Research suggests that 15% of the total software development cost should be allocated to implementing a maintenance model for a software system. Unused components or noncompliant software will increase over the project’s life cycle. The discontinuation of some
systems may reduce the resources required to maintain the system. Deciding how many resources
to allocate for maintenance for each subsystem can be challenging without a suitable
software maintenance prioritisation method.
Software logging is crucial to improve software maintenance by troubleshooting. In extensive
software systems, logging enables the development team to monitor specific events. A
suitable logging mechanism can identify the most used software system. In web-based applications,
the user interactions with each software system can be determined by capturing
user-based events.
Analysing logs can be challenging if the logging mechanism does not track the desired userbased
events. Developing a method to track these events for a specific purpose is more
efficient and reliable. The author suggests integrating the method to create a logging mechanism
and a log analysis to prioritise software maintenance.
The method for this study was divided into two main functional parts, namely the logging
mechanism and the log analysis. The characteristics of these user-based events, user types,
and user-based attributes are defined. The logging mechanism captures any user activity on
the software systems, and the logging points in strategic locations in the software systems
capture the log attributes. HTTP requests have more significant and relevant data about a
specific event. Additional data from request parameters are obtained as metadata that can
be used for system diagnostic purposes.
For the log analysis for this study, log quality is monitored to ensure that event logs are consistent,
reliable, and complete to create prioritisation recommendations for software maintenance.
A test system validates the method’s work, making modifications where needed. The
results of this method applied to case studies proved that the method can prioritise software
maintenance. The results are evaluated and discussed, and positive and negative points are
highlighted by implementing this method. Therefore, the study objectives have addressed
the need to develop a method for log analysis for software maintenance by creating a suitable
logging mechanism to capture user-based event logs.-ETA-Operations (Pty) Ltd
-IPGIP-bursaryMaster
Political Patronage in South Africa Local Government: Is the Local Government: Municipal Systems Amendment Act Helping Matters?
Get PDFJournal Article, Faculty of Humanities, Afrocentric Governance of Public Affairs (AGoPA)-- Vanderbijlpark CampusOne of the lead precursors to unstable local governance in the contemporary South Africa pertains to the embedded culture of political patronage. It is believed that the provisions added to the newly amended version of the Local Government: Municipal Systems Act 3 of 2022, which among other things, limits the political rights of officials, will somehow counter the existing patronage patterns. While this Amendment Act is a step in the right direction in as far as professionalisation of the local government sector is concerned, the question that this article attempts to answer is: will this attempt to insulate officials from politics result in stable municipal administrations, ethical conduct, professionalism, service delivery and less political interference? In addition, what are the ramifications that political parties are likely to encounter as a result of the curtailed political rights of their members? One of the findings is that the inserted changes are going to destabilise, firstly, the intra-party arrangements at political level, and secondly, will uproot elements of favouritism, nepotism and to some extent frustrate the existing culture of patronage in municipalities. However, it must be acknowledged that this is not going to be easy, given the damage already done such as bloated organograms, and the practice of cadre deployment which is facilitated by ruling parties in councils. With local government being at the coalface of service delivery and development, professionalisation is crucial but there is also a need to cultivate and encourage a strong ethos and philosophy of praxis underpinned by Ubuntu, the African philosophy
A draft tube to improve mixing in swirling flow-based solid–liquid mixing reactors
Get PDFJournal Article, Faculty of Natural and Agricultural Sciences, Material Science Innovation and Modelling (MaSIM)-- Mahikeng CampusThe Swirl Flow Reactor (SFR) is a recently proposed specially designed reactor to address challenges of solid liquid mixing for high-temperature and high-pressure processes. Previous research has shown that the mixing homogeneity of the SFR is not yet optimal and has still potential for improvement. To enhance the homogeneity of the SFR and to optimize the utilization of the previously identified Precessing Vortex Core at the nozzle, an improvement is proposed by the inclusion of a draft tube in the reactor center. Computational Fluid Dynamics is used to study the flow structure, particle distribution, and large-scale coherent structures in the SFR. The improved SFR has been validated for its more homogeneous mixing, where the homogeneity is improved from 0.945 for the original reactor to 0.991 in the new proposed design. Also, the influence of the draft tube on the fluctuating velocities and turbulence within the improved SFR has been indicated. In addition, Spectral Proper Orthogonal Decomposition (SPOD) is used to identify and reconstruct the coherent structures in the reactor. A flattened double-layer helical precessing vortex core (PVC) and its second-order harmonic at frequencies of 35.8 Hz and 71 Hz have been identified, which introduce extra large scale mixing near the nozzle of the reactor.Acknowledgments
The funding of this research by the ‘Dienst onderzoekscoördinatie (DOC) KU Leuven’ through grant number C3/19/015 is gratefully acknowledged. The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center), funded by the Research Foundation - Flanders (FWO) and the Flemish Government – department EW