DSpace Repository

Welcome to the NWU Repository, the open access Institutional Repository of the North-West University (NWU-IR). This is a digital archive that collects, preserves and distributes research material created by members of NWU. The aim of the NWU-IR is to increase the visibility, availability and impact of the research output of the North-West University through Open Access, search engine indexing and harvesting by several initiatives.

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Recent Submissions

Development of an integrated continuous improvement and innovation thinking model for a South African Bank
(North-West University, 2026) Richards, Y; Coetzee, R
Companies cannot succeed without actively focusing on both Continuous Improvement and Innovation Thinking simultaneously. Often, organisations apply these methodologies in isolationor use only one. In South Africa's banking industry, a clear gap has been identified in the lack of integrated implementation of Continuous Improvement and Innovation Thinking. This research aimed to explore how these two concepts could be integrated into an improvement strategy specifically for the South African banking sector. The research involved reviewing the latest literature on Continuous Improvement and Innovation Thinking methodologies used across various countries and industries. It also sought to determine the root causes for the failure to utilise and combine both methods through a qualitative study. Additionally, the study aimed to identify the elements necessary for a theoretical framework integrating Continuous Improvement and Innovation Thinking. This was done through interviews with banking practitioners specialising in both of these areas.The ultimate goal was to develop a verified and validated (evaluated) artefact that integrates Continuous Improvement and Innovation Thinking for the banking sector in South Africa. This artefact was informed by both literature and interview findings, highlighting identified challenges and proposing solutions. The resulting integrated model incorporates different phases tailored to the organisation's maturity level, acknowledging that various areas may have distinct levels of maturity in Continuous Improvement and innovation. The new model includes various Continuous Improvement and Innovation methodologies along with their respective steps. It also specifies different roles for participants in each phase, depending on the organisation's maturity level. This study offers an integrated solution to issues that were previously addressed separately. The new integrated model will help companies drive Continuous Improvement and innovation in a coordinated way, which is essential for maintaining market competitiveness.
Afrikaanse jeugtaal: 'n ondersoek na die taalgebruik van bruin jeugdiges
(North-West University, 2025) Steyn, BN; Kirsten, J; Bekker, I
Die interaksie tussen linguistiese variasie, sosiale betekenis en die evolusie en ontwikkeling van die linguistiese sisteem self is waarna Tagliamonte (2006:5) verwys as variasie-sosiolinguistiek. Die impak van sosiale en linguistiese faktore op taalvariasie en -verandering is van belang vir variasie-sosiolinguiste (Hadei, 2020:3). Eckert (2018) maak 'n onderskeid tussen drie strominge van variasiestudies, en beklemtoon dat die derde stroming meer aandag gee aan die betekenis van variasie in plaas van grootskaalse stedelikeopnamestudies of etnografiese studies van plaaslike dinamika, wat in die vorige strominge voorgekom het. Hierdie studie beoog om linguistiese variasie te bespreek vanuit 'n derdestromingbenadering tot variasiestudies, wat gebaseer is op die praktykgemeenskappe wat in die skoolomgewing gevind word.Hoërskool is 'n sosiale plek vir interaksies sowel as om akademies uit te blink vir baie bruin jeugdiges. Die benutting van grammatikale variante deur sprekers in verband met die ontwikkeling van sosiale identiteite in die opvoedkundige omgewing word in hierdie studie bestudeer. Hierdie studie fokus op 'n groep leerders by 'n township-skool (Noordwes-provinsie)in die noordoostelike dele van Suid-Afrika. Sosiolinguistiese onderhoude is met leerders van verskeie sosiale groepe (soos klevaas, moegoes en draadsitters) van 16-21-jariges gevoer nadat hulle waargeneem is in die skoolomgewing. Hierdie studie fokus op sewe (7) Afrikaanse grammatikale verskynsels: besitskonstruksie (hom/sy), genitiewe se met voornaamwoorde (onse/ons), werkwoordkonstruksies (gehet/gehad en is (was)/wees) en idiosinkratiese verskynsels: ongewone meervoudsvorme (huise/huis), wisselvorme van versamelnaamwoord (goeterse/goete), e-klankbyvoeging (beginne/begin). Hierdie spesifieke linguistiese veranderlikes is om twee redes gekies: aangesien grammatikale verskynsels sosiaal opvallend is en sosiale betekenisse het wat met die frekwente gebruik daarvan geassosieer word, het hierdie studie ten doel gehad om te bepaal tot watter mate die verskillende variante gebruik word. Aan die een kant het Saal en Lawrence (2019) onder meer bevind dat hierdie grammatikale verskynsels geassosieer word met tieners se (geskrewe) taalgebruik; en aan die ander kant het Marais (2005) se studie, wat wit tieners uit die noordoostelike dele van die land ingesluit het, nie die taalgebruik van bruin jeugdiges in haar studie verreken het nie. Die linguistiese variasie wat in hierdie studie ondersoek is, word dus gebruik om die leemtes in die literatuur aan te vul oor die (gesproke) taalgebruik van bruin jeugdiges vanuit die noordoostelike dele van Suid-Afrika.As alles saamgevat word, kan verskeie variasiemetodes 'n meer omvattende en geïntegreerde sosiolinguistiese analise verskaf, soos hierdie studie demonstreer. Deur deelnemers te identifiseer en te klassifiseer in hul toepaslike sosiale groeperings, is waarnemings en anekdotiese rekords gebruik om beskrywende data oor die verskillende sosiale groeperings te verskaf. Ten einde die kenmerkende grammatikale verskynsels van deelnemers op grond van hul sosiale groeperings vas te stel, is individuele onderhoude daarna gevoer. Wat linguistiese variasie in hierdie township-skool betref, voer ek aan dat leerders se stilistiese gebruik van hierdie linguistiese praktyke sosiaal en geslagtelik gemerk is. Byvoorbeeld, die veranderlike ons was 'n sosiale merker, wat deur die moegoes gebruik is. En wat geslag betref, het die seuns wees en beginne verkies, terwyl voorkeur gegee is aan is (was) en begin deur die meisies.
Mode of occurrence and behaviour of mineral matter in fine coal rejects during thermal treatment
(North-West University, 2024) Mphahlele, K; Bunt, JR; Matjie, RH
The use of coal as a primary energy source remains of interest globally due to its contribution to economic development and the affordable and reliable energy. However, the depletion of coal reserves and increased energy demand highlight the need to valorise coal wastes such as finecoal rejects (FCR). In addition, conventional disposal of FCR poses significant threats to human health and the environment due to emissions of H2S, SO2, CO2, heavy metals/metallic inorganic elements such as cadmium and arsenic, as well as volatile organic compounds (VOCs) arising from pyrite-associated spontaneous combustion and the interaction of organic sulphur and calcium within the FCRs. Direct utilisation of FCR in conventional boilers and gasifiers with highash yield, high moisture content, and fine particle size may create downstream problems such as slagging, fouling, and erosion during utilisation. This is especially true if the transformational behaviour of the mineral matter (ash forming part of coal) is not fully understood. Discerning the FCR mineral matter has the potential to allow for the utilisation of FCR in conventional boilers and gasifiers as a co-feed to traditional feedstocks. This can extend coal energy security, minimise coal waste handling costs and alleviate/mitigate environmental challenges associated with FCR disposal. These benefits may be achieved by better understanding the mode of occurrence of mineral matter and its behaviour during thermal treatment. This research investigates the potential for utilisation of South African FCR in gasification and pyrolysis processes and aims to address environmental concerns and reduce disposal costs associated with this coal waste. Previous studies have focused primarily on unoxidised FCRs, particularly steam-station coals (labelled STEM in this study), and neglecting the partially oxidisedFCRs, such as those from thermal-export plants (labelled TEP in this study) and their beneficiated fractions. This investigation comprehensively characterised and compared two types of South African FCRs, one from TEP and the other from STEM. The FCRs exhibited properties similar to those of feed coals for gasification and combustion, with notable differences in the mineral matter and vitrinite proportions and the alkali index, which is higher in the TEP sample. Thermogravimetric-gasification experiments demonstrated higher reaction rates and carbon conversion for the TEP sample, indicating its superior reactivity compared to the STEM sample. Raman and X-ray diffraction analyses revealed the presence of aromatic and aliphatic hydrocarbons and mineral matter in the FCRs, contributing positively to coal gasification reactivity. An exploration of the mode of occurrence of mineral matter in FCR was also conducted by employing density-separation, chemical fractionation, and demineralisation techniques. This approach divided FCR mineral matter into different modes of occurrence, including extraneous minerals and inherent mineral matter (ion-exchangeable cations, salts of carboxylic acids and submicron minerals). The influence of extraneous minerals was studied by blending FCR and its density-separated, chemically fractionated, and demineralised residues with a composite of reactive oxides (MgO and Fe2O3) and a hydrated oxide mineral (Ca(OH)2). The results indicated an enhanced activation energy during pyrolysis, resulting in increased carbon conversion. Cleat minerals and extraneous minerals catalysed pyrolysis reactions, facilitating the cracking of heavy tars to lighter fractions. However, the presence of oxygen in the reactive oxides hindered deoxygenation reactions, affecting pyrolysis efficiency. The study also investigated the effects of carboxylate salts on FCR pyrolysis, particularly ferrous acetate, magnesium acetate and calcium acetate as Fe2+/Mg/Ca-acetate composite. The results revealed the catalytic potential dependency on FCR carbon conversion on inherent mineral matter and its association with the dominant maceral groups. Adding carboxylate salts led to enhanced decomposition rates, carbon conversion, and the formation of sulphur-bearing phases and nanocarbonates, which influenced tar yield and gas composition. Overall, this research provides valuable insights into the reactivity and mode of occurrence of mineral matter in FCR, offering a foundation for their utilisation in gasification and pyrolysis applications. Understanding these properties makes it possible to mitigate disposal costs, health hazards, air pollution, and fines volume accumulation of FCR, thereby promoting their sustainable utilisation in the energy sector.
Improving advanced M&V by incorporating real time unplanned event identification on deep-level mines
(North-West University, 2024) Matthee, FJL; Marais, JH; Pascoe, J
Baselines and budgets play a crucial role in the monitoring of energy-saving initiatives by measurement and verification (M&V) specialists. While budgets are primarily designed for cost planning, baselines serve as historical benchmarks to discern improvements over time. The advent of advanced metering infrastructure has revolutionized the assessment of progress in real-time, giving rise to advanced M&V processes. This evolution includes the integration of data forecasting techniques, such as machine learning and regression models. However, existing models often focus solely on comparing results to a constant baseline, neglecting the impact of operational changes like unplanned events, which are scarcely addressed in the literature. This study aims to develop a predictive energy consumption model that accommodates operational changes and provides practical guidelines for handling unplanned events in deep-level mines. The approach employs the Moving Average (MA) equation to predict monthly energy consumption based on historical data. This prediction serves as a baseline, compared with a second prediction incorporating actual energy consumption data for each day. The resulting error is monitored to detect changes in operations, utilizing the guidelines as a reference. The developed model and guidelines were applied to two deep-level mining systems lacking advanced M&V implementation. The model successfully identified unplanned events in both cases, significantly reducing the time spent compared to traditional M&V processes. In case study A, where a water pipe issue went unnoticed for 97 days, the model could have expedited Improving advanced M&V by incorporating real time unplanned event identification on deep-level mines the identification and correction process by approximately 70 days, representing a 72% improvement. In case study B, where compressed air control valve failures were masked by another initiative, leading to a delayed investigation three months later, the prediction model could have saved 82% of the timeline. The combined potential savings on both case studies amount to R1.6 million, underscoring the critical need for real-time unplanned event identification in deep-level mines through the application of advanced M&V principles.
A deep learning framework for expert-guided sailplane performance optimisation
(Elsevier, 2026) le Roux, Vincent; Davel, Marelie; Bosman, Johan
The aerodynamic optimisation of high-performance aircraft is traditionally hampered by computationally prohibitive simulations, limiting the scope and agility of design space exploration. To overcome this barrier, we introduce a unified, data-driven framework founded on deep neural networks that enables rapid, expertguided optimisation. The framework replaces the conventional simulation pipeline with a suite of bespoke deep learning models: one for the controllable generation of airfoils from intuitive geometric parameters, and another for their instantaneous 2D performance prediction. Applied to the optimisation of a stateof-the-art 15-meter standard class sailplane, the framework achieved a mean lift-to-drag ratio increase of 1.26% over a competitive baseline, while rigorously adhering to all user-defined geometric constraints. The results demonstrate that combining expert-defined geometric constraints with data-driven design exploration can substantially reduce computational overhead while maintaining physical interpretability in preliminary aerodynamic design.