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Analysis of lift and drag forces on the wing of the underwater glider
No full textThesis (Master of Engineering in Mechanical Engineering)--Cape Peninsula University of Technology, 2018.Underwater glider wings are the lifting surfaces of unmanned underwater vehicles UUVs depending on the chosen aerofoil sections. The efficiency as well as the performance of an underwater glider mostly depends on the hydrodynamic characteristics such as lift, drag, lift to drag ratio, etc of the wings. Among other factors, the geometric properties of the glider wing are also crucial to underwater glider performance. This study presents an opportunity for the numerical investigation to improve the hydrodynamic performance by incorporating curvature at the trailing edge of a wing as oppose to the standard straight or sharp trailing edge. A CAD model with straight leading edge and trailing edge was prepared with NACA 0016 using SolidWorks 2017. The operating conditions were setup such that the inlet speed varies from 0.1 to 0.5 m/s representing a Reynolds number 27.8 x 10ᵌ and 53 x 10ᵌ.
The static pressure at different angles of attack (AOA) which varies from 2 to 16degrees at the increment of 2degrees for three turbulent models (K-Ԑ-standard, K-Ԑ-RNG and K-Ԑ-Realizable), was computed for upper and lower surfaces of the modified wing model using ANSYS Fluent 18.1. Thereafter the static pressure distribution, lift coefficient, drag coefficient, lift to drag ratio and pressure coefficient for both upper and lower surfaces were analysed. The findings showed that the lift and drag coefficient are influenced by the AOA and the inlet speed. If these parameters change the performance of the underwater glider changes as depicted by figure 5.6 and figure 5.7. The hydrodynamics of the underwater glider wing is optimized using the Cʟ/Cᴅ ratio as function of the operating conditions (AOA and the inlet speed). The investigation showed that the optimal design point of the AOA of 12 degrees and a corresponding inlet speed of 0.26m/s. The critical AOA matched with the optimal design point AOA of 12 degrees. It was also observed that Cp varies across the wing span. The results showed the Cp is higher closer to the fuselage while decreasing towards the mid-span and at the tip of the wing. This showed that the wing experiences more stress close to the fuselage than the rest of the wing span which implies that a higher structural rigidity is required close to the fuselage. The results of the drag and lift curves correspond to the wing characteristics typical observed for this type of aerofoil
Effect of microbial consortium on the biokinetic test for assessing acid rock drainage potential
No full textThesis (Master of Engineering in Chemical Engineering)--Cape Peninsula University of Technology, 2018.Acid rock drainage (ARD) is one of the most severe environmental challenges currently faced by the mining industry worldwide. ARD is formed from the oxidation of sulphide-bearing minerals, particularly pyrite, in the presence of water and oxygen. ARD generation is accelerated by the presence of naturally occurring iron and sulphur-oxidizing micro-organisms, which regenerate leaching agents that facilitate sulphide mineral oxidation. ARD pollution is characterized by a high concentration of metals and sulphates in solution, low pH and a high salt content (salinity) in the environment, contaminating soil and groundwater. In South Africa, ARD is a major challenge in the gold and coal mining industries, where millions of tons of sulphide waste rock and overburden are generated and discarded. Characterization of these waste materials is required to develop an appropriate disposal strategy to minimise the risk of pollution and the generation of ARD. Potential ARD generation prediction from waste rock depends on the precise characterization of ARD potential using Biokinetic tests. Commonly used ARD prediction methods are static and long-term kinetic tests. Static tests provide data for a worst-case scenario focussing on strong acid chemical leaching potential to give an overall acid forming potential of a sample. Such kinetic tests provide data illustrating the rate of the net acid generation capacity of mine waste. However, these tests are capital intensive and time-consuming and fail to provide adequate information on the effect of micro-organisms on the overall net acid generation capacity of mine waste. The Biokinetic test reported herein and developed at the University of Cape Town, focusses on addressing a worst case scenario provided by static tests in a cost-effective manner and reduced time frames provided for by conventional kinetic tests. This test primarily provides relative rates of ARD generation in the presence of micro-organisms within 90 days. However, the Biokinetic test is at the developmental stage and thus far, has not been consistently used for different waste ores to determine a standardised approach. Therefore, the aim of this study was to investigate the effects of microbial consortia and to develop a standardisation approach for the test for ARD formation potential using gold-bearing and copper-bearing waste rock. Additionally, to refine the Semi-continuous Biokinetic test simulation, a flow-through system where there is minimal seepage in the waste deposit, was also developed. The sulphur content of the gold and copper-bearing samples used in this study was between 2.3 and 3.15%, respectively. These waste rock samples were found to be potentially acid- forming. In the Biokinetic test, finely milled waste rock samples were slurrified, inoculated with consortia and cultured under standard bioleaching conditions. Leaching and acidification rates were monitored
The institutionalisation of an information security culture in a petroleum organisation in the Western Cape
No full textThesis (MTech (Information Technology))--Cape Peninsula University of Technology, 2018.In today’s world, organisations cannot exist without having information readily available. The protection of information relies not only on technology but also on the behaviour of employees. The failure to institutionalise an information security culture inside an organisation will cause the continued occurrence of security breaches. The aim of the research is to explore how an information security culture can be institutionalised within a petroleum organisation in the Western Cape. The primary research question is posed as follows: “What are the factors affecting the institutionalisation of an information security culture?” To answer the research question, a study was conducted at a petroleum organisation in the Western Cape. A subjectivist ontological and interpretivist epistemological stance has been adopted and an inductive research approach was followed. The research strategy was a case study. Data for this study were gathered through interviews (12 in total) using semi-structured questionnaires. The data collected were transcribed, summarised, and categorised to provide a clear understanding of the data. For this study, twenty-four findings and seven themes were identified. The themes are: i) user awareness training and education; ii) user management; iii) compliance and monitoring; iv) change management; v) process simplification; vi) communication strategy; and vii) top management support. Guidelines are proposed, comprising four primary components. Ethical clearance to conduct the study was obtained from the Ethics committee of CPUT and permission to conduct the study was obtained from the Chief Information Officer (CIO) of the petroleum organisation. The findings point to collaboration between employees, the Information Security department, and management in order to institute a culture of security inside the organisation
Environmental stress effects on the phytochemistry and bioactivity responses of a South African medicinal bulbous plant, Tulbaghia violacea Harvey (Alliaceae)
No full textThesis (MTech (Horticulture))--Cape Peninsula University of Technology, 2018.Deteriorating living and environmental conditions have contributed to the increasing prevalence of diseases in plants and animals. In humans, accumulation of abnormally high levels of free radicals in the tissues has been implicated in many non-communicable diseases, such as diabetes, cancer, arthritis, ischemia, gastritis, obesity and asthma. Worldwide, there is recognition of need to improve plant and animal health. Tulbaghia violacea (Alliaceae) is a medicinal plant that is extensively harvested by traditional healers in the wild for its medicinal uses and if this practice continues, it may result in an unsolicited decline of the species in situ. Therefore, there is a need for cultivation of this species. Plant cultivation in a controlled environment for conservation purposes as well as the enhancement of yield and quality is gaining favour among farmers and consumers. The main aim of this study was to investigate the effects of altering the growing conditions by applying environmental stresses on the plant growth, antifungal and antioxidant activities of T. violacea, with the view of enhancing the future cultivation of this species for pharmaceutical companies, traditional healers and the horticulture industry. This study was divided into two parts, and the first part, which was further sub-divided into two separate preliminary experiments, is presented in chapter three. Simultaneous assessments of the effects of i) varied pH levels (pH 4, pH 6, pH 8) and ii) light intensity on plant growth, antioxidant-content and -capacity of extracts of T. violacea were carried out. The second part of the thesis consisted of a more detailed assessment of the above-mentioned independent variables and interactions thereof on plant growth, and antifungal activity of extracts of T. violacea. Results obtained from the first part of the study, showed that plants exposed to pH 6 showed a marked increase in plant height (from 25-37 cm) after 2 months of treatment although, generally, the variations of the different growth parameters among the pH treatments were not significant (p > 0.05). Antioxidant-contents and -capacity were not significantly different (p > 0.05) when pH treatments were compared. However, a high polyphenol content value (of 3 mg/g) occurred in leaves of plants exposed to pH 8. Overall, comparatively, there was no significant difference (p > 0.05) in antioxidant-content and -capacity when pH treatments. In the light experiment, decreasing light intensity led to the elongation of plant height. A higher mean shoot length of 34.6 cm was obtained under low light compared to normal light (26.5 cm) two months post-treatment. The results obtained in this study indicated that light had a significant affect (p < 0.05) on the vegetative growth of this species. In contrast, normal light intensity yielded higher antioxidant-content and -capacity. The polyphenol and flavanol content were fluctuating between the averages of 5.8 mg/g to 8.5 mg/g. Overall, there was a significant difference (p < 0.05) in the antioxidant-content and -capacity when low and normal light intensity treatments compared. In conclusion, both normal light intensity and at pH 8 induced better antioxidant results. In the second part of the study, chapter four, one-month old T. violacea plantlets were grown under two light intensities (low light and normal light) in a greenhouse and concurrently exposed to varying pH levels: pH 4, pH 6 and pH 8. Plants exposed to normal light received natural sunlight through the roof of the greenhouse, while low light intensity (40% reduction) was achieved using shade nets. Plants were drip irrigated with Nutrifeed fertilizer. Plant growth parameters such as height and fresh and dry weights were determined. Leaf samples were analysed for macro-and micro-nutrients contents. Antifungal tests were carried out on the plant extracts from the various treatments in an antifungal bioassay (minimum inhibitory concentration [MIC]). The experimental data collected were analysed using one and two-way analyses of variance (ANOVA), and Tukey HSD was used to separate the means at p < 0.05 level of significance. Varied effects of different pH levels (4, 6 and 8) and light intensities (low and normal) on plant height, and fresh and dry weights were recorded in the current study. A significant interactive (df, 2; F = 0.001; p < 0.001) effect between pH and light on fresh weight was observed. The results revealed that there was a significant difference (df, 2, 57; F = 12.63; p < 0.001) in dry weights with plants under normal light intensity and pH 4 treatment (8.285 ± 0.802 g) producing the highest dry weight. There was a significant interaction (df, 2; F = 6.4; p < 0.001) between pH and light intensity on plant dry weight. Extracts from plants grown under normal light intensity showed stronger antifungal activity at pH level 4, and MIC values ranged from 0.18 ± 0 to 0.375 ± 0.04 mg/ml at 6h and 1.5 ± 0 to 0.97 ± 0.18 mg/ml at 18h. In conclusion, this study demonstrated the interactive effects of pH and light intensity on the growth of T. violacea. These findings also confirmed that it is possible to enhance the cultivation of T. violacea under greenhouse conditions. Chapter 5 focused on the interactive effects of pH and watering regime on plant growth, nutrient uptake and antifungal activity of T. violacea plant extracts, grown hydroponically. The results showed that there were significant differences (p < 0.05) on plant growth parameters amongst the different watering regimes under normal light intensity. Broadly, two trends occurred in the results: firstly, more macro-nutrients were taken up by plants in the higher frequency watering intervals as opposed to higher tissue micronutrient nutrient values for plants grown under the lower light intensity conditions. The levels of N, P, K, Mg nutrient uptake differed significantly in plants (p < 0.001) among watering interval periods. On the other hand, plants simultaneously exposed to extended watering intervals of 21-day and low light intensity showed more bioactivity of the crude extracts against F. oxysporum in the MIC bioassay. Based on the current results, a combination of shorter watering interval and normal light intensity favoured plant growth and development, while plants grown under low light intensity with longer watering interval showed good bioactivity. Broadly, these results demonstrated that varying pH, light intensity, and watering regime can influence plant growth, secondary metabolite contents and antifungal activity of crude extracts of T. violacea. These findings will contribute to the current body of knowledge around cultivation of indigenous medicinal plants. The study will further benefit the conservation of medicinal plant initiatives, increased income of small-scale farmers and potentially promote indigenous knowledge by increasing the availability of South African medicinal plants
Salts and cocrystals of substituted phenylacetic acids
No full textThesis (Master of Applied Science in Chemistry)--Cape Peninsula University of Technology, 2018.The prediction of the single crystal structure that will form due to the combination of two or more compounds to form a multicomponent crystal is one of the important areas of research in crystal engineering. Since these compounds display different properties when combined as a single crystal, knowledge of synthesis and design of the resulting compound is essential. The formation of a multicomponent crystal, such as a salt or a cocrystal generally depends on the complementarity of the functional groups present on both components. This means that basicity and acidity of the functional groups present on the selected compounds need to be considered. This study investigated salts and cocrystals of 3-chloro-4-hydroxyphenylacetic acid (CHPAA) using the ΔpKa rule. The calculated ΔpKa values were recorded and correlated with the experimental analysis in predicting the outcome of the crystallisation experiments ie. salt or cocrystal formation. This was further confirmed by the analysis of the C-O bond lengths found in the crystal structures. Salts were obtained by combinations of CHPAA with several organic bases (co-formers) such as diethylamine, dibutylamine, 2-aminopyridine, 2-amino-4-methylpyridine, 2-amino-6-methylpyridine and 4-dimethylaminopyridine. The calculated ΔpKa values were within the range of salt formation. Furthermore, the experimental analysis also showed that all resulting compounds were salts. Cocrystals were obtained by reactions of nicotinamide, isonicotinamide, phenazine and 4,4’-bipyridine with CHPAA. Again, the calculated ΔpKa values predicted cocrystals as the new solid forms. Experimental analysis carried out also confirmed cocrystal formation. For all resulting compounds, the comparison of intermolecular interactions as well as supramolecular synthons were reported. All compounds were synthesised by slow evaporation techniques using various organic solvents and characterised by single crystal X-ray diffraction, powder X-ray diffraction, thermal analysis and Fourier transformer infrared spectroscopy. From the structural analysis, it was found that all resulting structures displayed strong N-H•••O and O-H•••O intermolecular interactions including weak interactions of C-H•••Cl, C-H•••O and C-H•••π for a few of the structures. Furthermore, comparison of the crystal structures showed that no packing arrangement similarity existed between the compounds
The ability of newly qualified teachers to integrate technology into their pedagogical practice
Get PDFThesis (DEd (Education))--Cape Peninsula University of Technology, 2018.Growing numbers of urban and rural South African classrooms are now occupied by learners accustomed to, or could easily learn how to use technology that they have been described as ‘digital natives’. In order to design lessons that facilitate knowledge acquisition in a way that is familiar and relevant to these digital natives in the 21st century classroom, teachers have to integrate technology into their daily practice.
In response to this situation, the National Department of Higher Education (NDoHE) has drafted an e-Education policy to inform schools about the use of technology for innovative teaching and enhanced learning. Provincial education departments are expected to drive this policy. In the context of the historically entrenched socio-economic inequalities in South African schools, the use of technology could be a key instrument in closing the gap between privileged and underprivileged communities. Currently the Western Cape Education Department is involved in many initiatives to make technology more available and accessible. Although some public schools in the Western Cape have been provided with various forms of technology for teachers to use in their teaching, much more needs to be done to encourage newly qualified teachers (NQTs) to adopt, adapt and use technology effectively in the classroom. This study aims to answer the key research question: What factors influence NQTs’ ability to integrate technology into their pedagogical practice? In order to explore these factors, concepts from the TPACK and UTAUT2 models, which constitute the conceptual framework of the study, were used to collect, analyse and interpret data. From a review of the relevant literature, it emerged that although the factors that influence NQTs’ ability to integrate technology into their pedagogy have been extensively investigated internationally, few studies have been conducted in South Africa as a whole, and even fewer in the Western Cape; which makes this a pioneering local study. Because of the importance of technology in the 21st century classroom, factors that influence teachers’ use of technology need constantly to be monitored in order for school leaders to formulate programmes to encourage more teachers to integrate technology into their lessons effectively
The use of non-financial performance measures by small and medium enterprises operating in the hotel industry, in the Cape Metropole
No full textThesis (MTech (Cost and Management Accounting))--Cape Peninsula University of Technology, 2018.Small and Medium Enterprises (SMEs) operating in the hotel industry in South Africa are perceived to be failing/underperforming partly due to their reluctance to use Non-Financial Performance Measures (NFPMs). The main purpose of this study was to determine the extent to which SMEs in the hotel industry use three categories of NFPMs, namely; customer oriented, internal business process as well as learning and innovation, for running their businesses. This objective requires quantitative data to determine the percentage of SMEs in the hotel sector that make use of NFPMS. Specifically, the study aimed to determine the types of NFPMs used by the SMEs, the purposes for which these measures are used, the perceived effectiveness of the NFPMs currently used, as well as the factors that inhibit SMEs from using NFPMs. To this end, a questionnaire survey was administered on owners/managers of 100 hotels operating in the Cape Metropole. Purposeful sampling method was employed.
Test of reliability of questionnaire was done during the experimental stage to ensure the stability, consistence, repeatability, or reproduction of the same results if questionnaires were to be administered to the same population using the same methodology at different times.
The results of the study revealed that customer oriented measures were the most frequently used NFPMs, while learning and innovation related measures were the least frequently used NFPMs by the sampled SMEs. Concerning the purpose for which SMEs use NFPMs, the results revealed that SMEs used the NFPMs mainly for: improving the profitability of their business, improving productivity and effectiveness, as well as for improving decision–making. As far as the perceived effectiveness of the NFPMs currently used by SMEs, the results revealed that customer oriented measures were perceived by the sampled respondents to be the most effective of the three NFPMs. With respect to the factors inhibiting SMEs’ use of NFPMs, the results revealed that the main factors were high cost of implementing these measures, incomparability of the measures to those of other SMEs due to their entity specific nature, difficulty in quantifying the NFPMs measures, as well as employee resistance.
This study fills a gap in the literature by making a significant contribution on the usage of NFPMs by SMEs. The study provides useful information on the usage of NFPMs that the Department of Small Business Development and Small Enterprise Development agency(SEDA) can use to inform the development of interventions aimed at reducing SMEs’ failure. These findings may also help SMEs to improve their usage of NFPMs in order to capitalise on the benefits gained from using these measures. Furthermore, these findings may help SMEs to overcome the factors that inhibit them from using NFPMs
Ant tree miner amyntas for intrusion detection
No full textThesis (MTech (Information Technology))--Cape Peninsula University of Technology, 2018.With the constant evolution of information systems, companies have to acclimatise to the vast increase of data flowing through their networks. Business processes rely heavily on information technology and operate within a framework of little to no space for interruptions. Cyber attacks aimed at interrupting business operations, false intrusion detections and leaked information burden companies with large monetary and reputational costs. Intrusion detection systems analyse network traffic to identify suspicious patterns that intent to compromise the system. Classifiers (algorithms) are used to classify the data within different categories e.g. malicious or normal network traffic. Recent surveys within intrusion detection highlight the need for improved detection techniques and warrant further experimentation for improvement. This experimental research project focuses on implementing swarm intelligence techniques within the intrusion detection domain. The Ant Tree Miner algorithm induces decision trees by using ant colony optimisation techniques. The Ant Tree Miner poses high accuracy with efficient results. However, limited research has been performed on this classifier in other domains such as intrusion detection. The research provides the intrusion detection domain with a new algorithm that improves upon results of decision trees and ant colony optimisation techniques when applied to the domain. The research has led to valuable insights into the Ant Tree Miner classifier within a previously unknown domain and created an intrusion detection benchmark for future researchers
Management of student misconduct at a TVET college in the Western Cape
No full textThesis (MEd)--Cape Peninsula University of Technology, 2018.Technical Vocational Education and Training (TVET) colleges play an important role in providing a competent workforce that can contribute to the economic development of South Africa. TVET Colleges also provide an alternative pathway for students who have not completed grade 12. TVET Colleges have seen many changes during the past decades and have reportedly been underperforming in various areas, including academically. Student misconduct may, amongst other factors, have a determining influence on the poor performance of TVET Colleges. Student misconduct comprises the nature of student misconduct, factors leading to student misconduct and management of student misconduct. The nature of student misconduct, factors leading to student misconduct and methods used to manage student misconduct at TVET Colleges remain largely unidentified and need to be researched. The purpose of this study is to determine the nature of student misconduct, factors leading to student misconduct and how student misconduct is managed at a TVET College in the Western Cape. The nature of student misconduct is classified into ordinary student misconduct and serious misconduct. Factors leading to student misconduct are classified into factors related to the management of TVET Colleges, lecturer qualifications and competence and student background and preparedness. Management of student misconduct is classified into reactive methods and preventative methods for managing student misconduct. The research methodology employed for this study was an explanatory mixed method. The explanatory mixed methodology collects quantitative data first and then, based on the quantitative findings, collects qualitative data to elaborate on the quantitative findings. The major findings of the quantitative phase created topics for further discussion during qualitative interviews. The study found that the most frequent forms of TVET student misconduct are ordinary forms of student misconduct such as absenteeism, playing with cellular phones in class and arriving late for lessons. The most frequent factors leading to student misconduct were found to be students becoming hungry during lessons, students coming from disadvantaged homes and students finding work too difficult. Students' home environment and level of academic preparedness therefore has an impact on their behaviour. Students who originate from disadvantaged homes, experience lack of provision in their basic needs, and also a lack of geborgenheit which lead to student disciplinary problems. As a counter measure, methods applied in the interest of managing student misconduct should include an atmosphere of geborgenheit. The study indicated that the most effective methods for managing student misconduct are the creation of a friendly classroom atmosphere, lecturer’s good subject knowledge, proper lesson preparation and positive student-lecturer relationships. A combination of the above-mentioned methods implies interesting lessons filled with activities that engage students who feel safe, loved and unconditionally accepted in their learning environment. When students feel safe and unconditionally accepted they experience an atmosphere of geborgenheit, a pre-requisite for management of student discipline. Poorly disciplined students, it was found, who display deliberate forms of student misconduct should be disciplined by means of stricter methods such as classroom rules and the disciplinary procedure. Methods applied in the interest of managing student misconduct should, however, be accompanied by an atmosphere of geborgenheit. Disciplinary measures should address misconduct from a position of love and unconditional acceptance. Students with behavioural problems need to be identified and referred to student support services for effective support. It is recommended that an early identification and support system be considered for early identification and referral of students with behavioural problems. Successful implementation of an early identification system should include the involvement health and welfare organisations and religious organisations. Student support services should, in addition, be expanded and posts created for educational psychologists to provide effective counselling to students with behavioural problems. TVET lecturers need to have workplace experience and qualifications, academic qualifications and teaching qualifications to enable them to present interesting, well prepared lessons using a variety of methodologies. It is recommended that TVET Colleges and the DHET invest in upgrading the qualifications of TVET lecturers through bursary schemes, time off at work and salary scales that are linked to qualification levels
Application of near infrared spectroscopy and chemometrics for the analysis of nutraceuticals in South Africa
No full textThesis (Master of Applied Sciences in Chemistry)--Cape Peninsula University of Technology, 2018.The high demand of omega-3 fish oil nutraceuticals (dietary supplements) is due to the numerous health benefits contributed by the polyunsaturated fatty acids (PUFA’s). The nutraceutical industry is required to follow good manufacturing practice (GMP) standards in order to ensure label claims and prevent adulteration. It is vital that the quality control (QC) procedures will be able to detect adulterated products. It is thus necessary to ensure the analytical techniques are adequate by using validated methods. The qualification or identification of natural fish oils is a difficult task due to overlapping concentration ranges of PUFA’s and other similar properties. Gas chromatography (GC) is the prescribed technique in the nutraceutical industry for analysis of omega-3 fatty acids, but it is time-consuming and costly. Near infrared (NIR) spectroscopy is a rapid and cost-effective technique that can replace the prescribed method if proven equivalent, through validation according to pharmaceutical criteria. In this study, NIR spectroscopy in combination with chemometrics was considered as an alternative method to GC, to identify various commercial fish oils and to quantify the PUFA’s. Identification methods were developed for nine commercial omega-3 fish oils using spectral libraries. Quantitative NIR methods were developed for arachidonic acid (AA), docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) in fish oils expressed as mg.g-1 as well as percentage (%) area using partial least squares (PLS) regression and independent validation by superimposing datasets with mutual properties. Based on the statistics in terms of SEC, R2, SEP and r of the PUFA models, the NIR method was equivalent to the prescribed GC methods and precision results obtained were within the prescribed criteria. NIR spectroscopy and chemometrics can be used for conclusive identification and quantification of omega-3 fish oils, thereby minimizing the risk of adulteration. The method also complied with the prescribed pharmaceutical method validation criteria; therefore, was demonstrated as an alternative method to GC for the nutraceutical industry