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Inhibiting carbon dioxide hydrate formation using deep eutectic solvents
Get PDFA thesis submitted in full fulfillment of the Degree of Master of Engineering in Chemical Engineering, Durban University of Technology, Durban, 2023.The formation of gas hydrates in pipelines during gas and petroleum extraction processes can result in multiphase systems including gas hydrates. These will form as solids in the presence of water and gas under thermodynamically favourable temperature and pressure conditions. Gas hydrates raise safety concerns, hinder process performance, and impact on financial resources as they block pipelines. The formation of gas hydrates can be efficiently prevented by using certain substances referred to as inhibitors. However, most inhibitors are expensive, potentially dangerous, and damaging to the environment. Hence, there is need to investigate environmentally friendly alternatives to mitigate gas hydrates. The objective of this study was to examine the efficiency of green additives referred to as deep eutectic solvents (DES) in inhibiting carbon dioxide gas hydrate formation. Deep eutectic solvents consisting of Tetrapropylammonium bromide + glycerol (DES-1), Tetramethylammonium chloride + glycerol (DES-2), and Tetramethylammonium chloride + ethylene glycol (DES-3) on carbon dioxide hydrates is investigated. These solvents are worth studying because their synthesis, purification, and environmental friendliness offer economic advantages. Molecular Dynamics (MD) simulations were used to theoretically determine the conditions that promote or inhibit the formation and stability of cardon dioxide hydrates in the presence of the selected inhibitors. The conditions investigated include temperature, pressure, and inhibitor concentration. The use of rigorous computational methods for preliminary screening significantly reduces the cost and the duration of experiments. MD simulation results were further validated using experimental gas hydrate equilibrium data. Results obtained in the present study indicated that the various DES solutions have both inhibiting and promoting effects. It was also found that low concentrations promoted hydrate dissociation, whereas high concentration greater than 0,20 stabilised hydrate formation. Pressure and temperature also impacted on the concentration of the DES solutions that inhibited or promoted hydrate formation. The concentration of the DES solutions shifted the hydrate curve to inhibit or promote hydrate formation.
In vitro antioxidant, mineral analysis and antimicrobial activities of extract and fractions from the aerial part of Heterotis rotundifolia (Sm.) Jacq. Fel
Get PDFHeterotis rountidifolia (Sm.) Jacq. Fel, is employed in Nigeria traditional medicine for the treatment of various diseases. The study investigated the antioxidant, mineral composition and antimicrobial activities of aerial part of Heterotis rotundifolia using standard procedures. The proximate composition on dry matter basis showed high carbohydrate (48.41%) and low lipid (0.77%) contents while mineral content revealed that sodium (5.68 mg/100 g) and zinc (4.64 mg/100 g) were the highest. The total caloric value per 100 g was 260.93 kcal. Methanol (ME) fraction exhibited the highest radical scavenging (EC50 = 59.36 µg/mL) and reducing (EC50 = 76.54 µg/mL) activity. Contents of total flavonoids and phenolics were highest in ME and ethyl acetate (EAE) fractions (39.2 mg GAE/g and 183.5 mg RE/g, respectively), while hexane (HE) fraction showed the lowest radical scavenging, ferric reducing and nitric oxide assay (EC50 = 268.56, 87.86, and 98.30 µg/mL, respectively). The minimum inhibitory concentration (MIC) and minimum bactericidal/fungicidal concentration (MBC/MFC) against various bacterial and fungal strains using tube dilution method showed strong activity at MIC of 50 mg/mL depicted by n-HE fraction, though lower MBC of 37.5 mg/mL by ME fraction made the ME fraction of better potentials. Gas chromatography-mass spectrum (GC-MS) analysis of the ME fraction revealed 5-Hydroxymethylfurfural (16.87%), Methyl 6-O-[1-methylpropyl]-β-D-galactopyranoside (16.07%), 4H-Pyran-4-one,2,3-dihydro-3,5-dihydroxy- (8.28%), 6-methyl-β-D-glucopyranose, 1,6-anhydro- (6.56%), 2-heptanol (6.82%), stigmastan-3,5-diene (4.32%) amongst others. This research demonstrates that extract and fractions from aerial part of H. rotundifolia possesses antioxidant, antimicrobial and nutritive potentials, albeit with generally weak antifungal activity and, may be attributed to the presence of its phytochemical constituents.Keywords: </p
Entrepreneurship education and economic emancipation of youths in Oyo State, Nigeria, West Africa
Get PDFThe primary aim of every citizen in any nation of the world is to be economically emancipated, as it enables one to be self-reliant rather than depending on parents, guardians or government for survival. However, the majority of Nigerian youths are living in abject poverty compared to their counterparts in developed countries. In an attempt to find a solution to the problem of acute poverty, this study investigated the relationship between entrepreneurship, education and the economic emancipation of youths in the Ibadan Metropolis, Oyo State, Nigeria. A sample of 350 respondents was selected through the purposive sampling technique. Three hypotheses were tested. A self-designed online survey questionnaire titled “Entrepreneurship Education and Economic Emancipation Questionnaire (EEEEQ)” was administered and used for data collection. Pearson Product Moment Correlation (PPMC) and multiple regression analysis were the statistical tools employed for data analysis. The findings revealed a significant relationship between entrepreneurship knowledge and economic emancipation among youths in Ibadan Metropolis, Oyo State, Nigeria (r=0.78, p<0.05). It was also shown that entrepreneurial skills and economic emancipation among youths in Ibadan Metropolis, Oyo State, Nigeria were significantly related (r=0.63, p<0.05). Based on the findings of the study, it was recommended that more emphasis should be given to entrepreneurial skill acquisition and to the adequate provision of learning tools and materials. Government should also make available grants for youth with potential to demonstrate and maximize their acquired entrepreneurial knowledge and skills.</jats:p
The relationship between SME financial sustainability and owners’ financial well-being in South Africa
Get PDFThis study examines the relationship between financial sustainability and the financial well-being of SME owners in Durban, South Africa. Utilising a quantitative research design, data were gathered through close-ended surveys from a diverse cross-section of SME owners, employing a cross-sectional approach.The study adopted a positivist philosophical framework, emphasising quantitative data analysis to derive conclusions. A total of 250 responses were collected, yielding a robust response rate of 82%. The analysis involved descriptive statistics and correlation analysis, with the correlation matrix revealing a positive, statistically significant correlation (r = 0.504, p < 0.05) between financial sustainability and financial well-being. The findings indicate that higher levels of financial sustainability are associated with greater financial well-being among SME owners, though the strength of this relationship is moderate. The regression analysis further supports this positive association, suggesting that interventions aimed at enhancing financial sustainability may significantly improve the financial well-being of SME owners. These results align with the theoretical framework of the Easterlin Paradox, which highlights the relative importance of financial stability in enhancing overall well-being. Based on these findings, several recommendations are proposed, including fostering financial literacy, enhancing access to financial resources, and promoting entrepreneurial collaboration
Macroeconomic and firm-specific determinants of financial performance : evidence from non-life insurance companies in Africa
Get PDFThis study aimed to examine the macroeconomic and firm-specific determinants of financial performance using 121 listed non-life insurance companies from 48 African countries for the period 2008–2019. Panel data of 1452 observations were examined using both ordinary least squares and two-step System Generalised Method of Moments estimators. The findings of this study show that lagged return on assets, equity capital, operational efficiency and leverage, investment capability and gross domestic product are the statistically significant determinants of financial performance in African non-life insurance companies even though equity capital, operational efficiency and leverage are inversely significant. It is concluded that insurance industries, policymakers, government and investors should take into consideration these significant factors in taking decision and improving their performance. Also, it is recommended that the capital structures of the sector should be restructured to maintain a favourable balance in the equity and debt of the companies. Also, mechanisms such as automated systems that can reduce operational cost should be adopted such that financial performance can be enhanced
Factors affecting the profitability of reinsurance companies in sub-Saharan Africa : evidence from dynamic panel analysis
Get PDFThis study, which analysed the profitability of 42 reinsurers in Sub-Saharan Africa from 1991 to 2020, revealed that various factors such as gross domestic product, competition (HHI), premium growth, investment performance, underwriting risk, and operational efficiency affect the profitability in these companies. This study is quantitative and dynamic using system-generalised method of moments to analyse the data. The study discovered that reinsurers should broaden their services to remain highly competitive and boost their premium growth such that their profitability is sustained. Also, there should be a separate department of qualified professionals overseeing the adequate management of risk before sealing ceding agreement with insurers
Enhancing the usability of a university student support services FAQ Chatbot
Get PDFSubmitted in fulfillment of the requirements of the Master of Information and Communications Technology Degree, Durban University of Technology, Durban, South Africa, 2024.Chatbots play a vital role in customer facing interaction. They offer real-time text or voice responses via intuitive human interaction systems and are often driven by AI technologies. Despite widespread adoption, their optimisation for university environments remains elusive. With a lens on Universities of Sub-Saharan Africa, this dissertation positions usability as essential in a chatbot’s ability to provide effective support for student support services. This dissertation identifies with the dire need for more rigorous design and development in line with the needs of a modern, inclusive university sensitive and responsive to its students’ varying degrees of multiculturalism, multilingualism, socio-economic standing and technology and digital literacy baseline skills. The topic of chatbot integration in University systems has received significant attention in recent years but few have focused on the interplay between usability factors such as, anthropomorphism, NLP, or UX. This has limited our understanding of how best to enhance chatbots, specifically in University student support services. This study aimed to identify the key design factors for an enhanced usability FAQ chatbot, tailored for University student support services. In pursuit of this aim, a usability design framework as well as a FAQ chatbot was developed and tested in a popular University in South Africa. The base functional requirements were inferred from extant literature and then fused with data collected from students and administrative members of staff. The design framework was also influenced by well-known usability principles and standards from ISO, Nielsen and Shneiderman and others. Google Dialogflow was used to develop the chatbot, architected by the design framework. Based on the DSR paradigm, the research followed a systematic approach encompassing usability design, framework development, tool evaluation, and FAQ chatbot development and testing. First-year students and administrative staff members were active participants and served as change agents during the iterative DSR process. Thematic analysis was used to carefully analyse the feedback from participants during the development stages and seed this into the ongoing design process. This iterative process of development and refinement allowed for a richer understanding of how users perceive and interact with the chatbot. During analysis of the final evaluation feedback, PLS-SEM illuminated relationships, dependencies and interactions among various usability design factors which influence the chatbot's overall usability. The major contribution is a blueprint for the design and development of an effective University student support services FAQ chatbot. Theoretical contributions include a usability design framework, iterative DSR development process and evaluation and feedback instruments using robust analysis techniques. There is a need for further research and refinement at the confluence of NLP, anthropomorphism and FAQ chatbot design frameworks.
Bio-inspired optimisation of a new cost model for minimising labour costs in computer networking infrastructure
Get PDFSubmitted in fulfillment of the requirements of the degree of Doctor of Philosophy in Information Technology (IT), Durban University of Technology, Durban, South Africa, 2024.This thesis revolves around the bio-inspired optimisation of a newly formulated cost model tailored for initial installation of a user-specified computer networking infrastructure, motivated by requirements of networking industries, with a focal point on minimising labour costs. The new cost function of this infrastructure installation incorporates essential decision variables related to labour, encompassing the daily requirements and costs of both skilled and unskilled workers, their respective hourly rates, installation hours, and the overall project duration. This deliberate emphasis on labour-centric factors aim to offer nuanced insights into the intricacies of project budgeting and resource allocation. The research critically evaluates the effectiveness of the cost function by examining various factors, such as daily fixed costs, a size and complexity factor tailored to individual scenarios, and a penalty coefficient aimed at ensuring compliance with project schedules. Significantly, the deliberate exclusion of equipment, material, maintenance and operational costs underscores the focused examination of labour-related expenditures, providing a unique contribution to the optimisation landscape within the installation of the user-specified computer networking infrastructure projects. Utilising advanced bio-inspired optimisation techniques, alongside real-world data, this study endeavours to gauge the effectiveness of the new cost model in minimising labour expenses while upholding optimal network performance. The anticipated outcomes of this study extend beyond theoretical contexts to practical implications, providing actionable insights and recommendations for network infrastructure planners. The significance of labour-centric considerations in project planning and design is underscored, providing a more encompassing perspective that aligns with the evolving landscape of modern technological infrastructures. By giving attention to labour-intensive aspects within installation of computer networking infrastructure projects, the thesis aspires to enhance budgeting accuracy and streamline resource allocation processes, thereby fostering more efficient and cost-effective project outcomes.
Health insurance cross-selling predictions with machine learning for South African consumers
Get PDFSubmission in completion of the requirements for the Degree of Master of Information and Communications Technology, Durban University of Technology, Durban, South Africa, 2024.Cross-selling is the practice of selling additional products or services to an existing customer to increase business revenue. Cross-selling health insurance is challenging for companies, as they spend significant time meeting with prospective clients without knowing the likelihood of a sale. A health insurance provider often markets additional insurance products to its clients through different channels. This study aims to develop a robust ML model to help health insurance companies identify potential customers likely to engage in cross-selling. Objectives include extracting and preparing customer data from a large South African insurance company using suitable ML techniques. The study also seeks to determine effective algorithms for predicting health insurance cross-selling and to identify influential features for algorithm selection. This study adopted a quantitative research approach focused on extracting health insurance customer data. To achieve this, the study applied ML techniques by using the Python language using a dataset obtained from a large South African insurance company which is a rich repository that contains demographics, health conditions, and policy information. The study applied various ML algorithms, including Random Forest, KNearest Neighbors, XGBoost classifier, and Logistic Regression, feature engineering techniques were employed to enhance predictive accuracy. Analyzing 1,000,000 customer records with 17 features, Random Forest emerged as the top model with an accuracy of 0.91 and an F1 score of 1.00. The study found that customers aged 2570, with prior insurance and longer service history, are more likely to purchase additional health insurance. This study will assist insurance providers in developing a strategy for reaching out to those clients in order to enhance their business operations and revenue.Cross-sellingMachine learning algorithmsHealth insurancePredictionFeature engineeringModel trainingModel evaluation metricsSupervised machine learningUnsupervised machine learning
On AI-iteration process for finding fixed points of enriched contraction and enriched nonexpansive mappings with application to fractional BVPs
No full textIn this article, we consider the AI-iteration process for approximating the fixed points of enriched
contraction and enriched nonexpansive mappings. Firstly, we prove the strong convergence of the AI-iteration
process to the fixed points of enriched contraction mappings. Furthermore, we present a numerical experiment to demonstrate the efficiency of the AI-iterative method over some existing methods. Secondly, we establish the weak and strong convergence results of AI-iteration method for enriched nonexpansive mappings in uniformly convex Banach spaces. Thirdly, the stability analysis results of the considered method is presented. Finally, we apply our results to the solution of fractional boundary value problems in Banach space