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Atomistic simulation studies of Li+, Na+ and Mg2+ inserted nano- architectured Ti02 for metal ion batteries
Get PDFThesis (Ph.D.(Chemistry)) -- University of Limpopo, 2023Since the rechargeable battery performance involving TiO2 anode strongly depends on its structural, transport and electrochemical properties, it is important to explore different TiO2 nanostructures in order to improve its operation through its ability of hosting mono and multivalent ions. Consequently, the current study involves synthesizing MxTiO2 (M = Li+, Na+, and Mg2+) (x= 0.11, 0.15, 0.19 and 0.23) nanospheres, nanoporous and nanosheets using the molecular dynamics based amorphization and recrystallization technique, employing a DL_POLY code. This is followed by predicting structural and mobile ion transport properties for future rechargeable batteries. Li+, Na+ and Mg2+ were inserted into the amorphous TiO2 nanosphere, nanoporous and nanosheet architectures in order to produce LixTiO2, NaxTiO2 and MgxTiO2 (x= 0.11, 0.15 ,0.19 and 0.23) for each nano-architecture. The amorphous nano-architectures were recrystallized by simulations at 2000 K and resultant structures were cooled from 1500 K to 0 K at intervals of 500 K. Finally all cooled nano-architectures at 0 K were analysed and subsequently heated to 2000 K at 100 K intervals. The TiO2 nanospheres with 0.11, 0.15, 0.23 Li+ and Na+ concentrations had similar microstructural defects, present in pure TiO2 and before Li insertion, characterised by dominant zigzag (brookite) and straight (rutile) tunnels with empty vacancies and Li+ and Na+ filled vacancies with few Li+ and Na+ located on the surface. On the other hand, the TiO2 nanospheres with 0,19 Li+ and Na+ concentrations remained amorphous after recrystallization, cooling and heating; hence their structural and microstructural features were not constructed. Surprisingly, the Mg0.19TiO2 nanosphere recrystallised successfully together with those of 0.11, 0.15, and 0.23 Mg2+ concentrations and their microstructures had zigzag (brookite), straight (rutile), tunnels with empty vacancies, Mg2+ filled vacancies and few Mg2+ were situated on the surfaces. The microstructures of the TiO2 nanoporous structures, with 0.11, 0.15, 0.19 and 0.23 Li+, Na+ and Mg2+ concentrations, showed crystalline patterns of zigzag tunnels (brookite), straight (rutile) tunnels with empty vacancies and Li+, Na+ and Mg2+ filled vacancies after being recrystallised and cooled, except for the 0.23 Mg2+ concentration which showed highly disordered patterns. The microstructures of TiO2 nanosheets, with 0.11, 0.15, 0.19 and 0.23 Li+, Na+ and Mg2+ concentrations, had a mixture of disordered and crystalline (ordered) patterns of zigzag (brookite) and straight (rutile) tunnels with few empty vacancies, and some were filled with Li+, Na+ and Mg2+ where most Li+ and Na+ ions were situated around the surface of the microstructure except for TiO2 nanosheets with 0.23 Mg2+ concentration which was amorphous, similar to that of Mg0.23TiO2 nanoporous architecture. All resulting TiO2 nanostructures and microstructures were further characterised and analyzed by their respective radial distribution functions (RDFs), simulated X-ray diffraction (XRD) patterns, diffusion coefficients and activation energies to study the effects of increased lithiation, sodiation, and magnesiation at various temperatures. The simulated Ti-O radial distribution functions were utilised to confirm the extent of crystallinity of nano-architectures after recrystallisation, cooling, and heating. In addition, simulated X-ray diffraction (XRD) patterns were employed to determine and compare crystallinity at low and elevated temperatures. Furthermore, they depicted rutile and brookite polymorphs in LixTiO2, NaxTiO2 and MgxTiO2, shown by our simulated microstructures, and observed in previous experimental and simulated studies of LixTiO2; which suggests possibility of easy and fast Li+, Na+ and Mg2+ ion passage in the current study. In the case of Li transport, for different nano-architectures, diffusion coefficients (DCs) for most Li concentrations were predominantly near zero at low temperatures and increased gradually above 500 K and significantly at higher temperatures beyond 1000 K. DCs of higher Li concentration nano-architectures tend to be highest. On the contrary, the diffusion coefficient of the amorphous Li0.19TiO2 nanosphere is elevated at low temperatures, however, it is exceeded by those of other concentrations at higher temperatures. On the whole the activation energies of Li in TiO2 nanosphere, nanoporous and nanosheet structures, in appropriate temperature range, were consistent with observed transport properties. In particular, the lowest activation energy for the amorphous Li0.19TiO2 nanosphere concurs with non-zero DC at lower temperatures. On Na transport in various TiO2 nano-architectures, DCs for most Na concentrations were predominantly near zero at low temperatures, except for the Na0.23TiO2 (associated explanation for such deviant behaviour is not yet available). Diffusion coefficients subsequently increased gradually above 500 K to substantial at higher temperatures, with DCs of higher Na concentrations in different nano-architectures tending to be highest; in particular the DC of the amorphous Na0.19TiO2 which was slightly higher than other crystalline NaxTiO2. The activation energy of the nanosphere with the highest Na concentration (Na0.23TiO2) was low, consistent with the trend of non-zero diffusion coefficients at low temperatures. The AEs of nanoporous structures at different Na contents were equivalent and related DCs almost overlap in the 500 to 1000 K range. In the case of nanosheets AEs are also almost equal for all NaxTiO2 with that of the Na0.23TiO2 (highest Na concentration) being highest resulting in a slightly lower diffusivity, except at very high temperatures. These results provide insights and an understanding on how much such TiO2 nano-architectures can enable operations of sodium ion batteries. Non-zero diffusion coefficients of Mg2+ commenced at lower temperatures in nanospheres, especially those with lower Mg concentrations. Related activation energies were also relatively low and increased with Mg2+ concentrations. However, in the nanoporous and nanosheet architectures, the Mg2+ DCs were almost zero below 1000 K and increased significantly above 1200 K with DC being highest in the heavily intercalated nanostructures. The activation energies for the latter two nano-architectures were in the range of 0.400 eV which is higher than in nanospheres, but comparable to those of the nanoporous Li-MnO2. Generally, on matching maximum diffusion coefficients of Li, Na and Mg mobile ions in TiO2 nano-architectures, it is apparent that they are all highest in nanospheres with DCLi > DCNa > DCMg. On comparing magnitudes of DCs in different nano-architectures the following trend emerges; for the monovalent Li and Na mobile ions DCSphere ~ 5DCPorous ~ 3DCSheet and for the divalent Mg mobile ion DCSphere ~ 2.5DCPorous ~ 2.5DCSheet. Such comparisons provide insights and an understanding on how much such TiO2 nano-architectures can enable performance of various mobile ion rechargeable batteriesNational Research Foundation (NRF) and
CSIR-Merseta bursar
Assessment of breeding practices, trait preferences of sheep farmers and sheep morphometric characterization in Makurung and Lenting Viillages of Lepelle-Nkumpi Local Municipality, Limpopo Province, South Africa
Get PDFThesis (M. Sc. (Animal Production)) -- University of Limpopo, 2024Sheep farming is practiced country wide, including in dry areas of Northern Cape, Western Cape and Limpopo Province. This study assessed the existence of production objectives, breeding practices, trait preferences of sheep farmers and morphometric characterization of sheep in two selected villages (Makurung and Lenting) of Lepelle-Nkumpi local municipality of Limpopo Province. Using 306 sheep of different classes, morphometric measurements were taken to characterize and predict body weight. Data was analyzed using Chi-square tests, descriptive statistics, rank index, Pearson’s correlation, analysis of variance (ANOVA) and various data mining algorithms such as Multivariate Adaptive Regression Spline (MARS) and Classification and Regression Tree (CART). Furthermore, MARS and CART were employed as data mining algorithms to determine the goodness of fit in body weight prediction from morphometric measurements. Socio-economic status results indicated that the majority of sheep farmers in the two surveyed villages were males, and there was no significant difference (P>0.05) observed between the villages. All the sheep farmers from Makurung village had tertiary education as their highest level of education, while in Lenting village majority of farmers had secondary education as their highest level of education, and there was a highly significant (P0.05) between the surveyed villages. Breeding practices indicated that a large proportion (90.00%) of sheep farmers in both villages practiced uncontrolled mating, and a highly significant difference (P0.05), while for breeding ewes, twinning ability (0.289), mothering ability (0.181), and lambing interval (0.168). Correlation results of rams in Makurung village showed that BW had a highly significant correlation with RH, HG, RL, WH and BL, While with rams of Lenting village, BW had a positive highly significant correlation with HG, WH, and BL. With ewes in Makurung village, BW had a highly significant correlation with RH, HG, WH and BL. While in Lenting village, BW had a highly significant correlation with RH, HG, RL, WH and BL. MARS and CART results indicated that HG had a significant effect (P<0.01) on WH, followed by BL, RH and the village. Goodness of fit criteria results indicated there was a high r (0.953), Rsq (0.900), ARsq (0.887) and low SDR (0.306) in MARS model, showing that this model was the best as compared with CART. The findings of this study imply that sheep farmers in Makurung and Lenting villages can read and write effectively and, therefore, can make decisions based on the design of CBBP. It was concluded that farmers in the two selected villages had household heads as male, who were married with education level of secondary and higher with ages ranging from 41-49. Sheep were kept mainly for saving and investment, with farmers having shown their highest preference for mating ability in rams and twinning ability in ewes. Most sheep farmers were not controlling the mating, with majority practicing culling and castration. In both sexes, BL, WH and HG can be used as a selection criterion when determining BW of sheep. Furthermore, both MARS and CART suggest that HG alone can be used as a predictor of BW in sheep. The goodness of fit calculations suggests that MARS was the best model. This study recommended that farmers, researchers, agricultural extension workers and other stake holders must collaborate in designing and implementing a community-based breeding programme by considering the production objectives, trait preferences and breeding practices.National Research Funding (NRF
Exploring grade 11 learners' intra-mathematical connections when solving trigonometric equations
Get PDFThesis (M.Ed. (Mathematics Education)) -- University of Limpopo, 2023This study explored the intra-mathematical connections that Grade 11 learners make
when solving trigonometric equations. The study was conducted in a high school in
Mankweng Circuit. A qualitative case study design was used in this study to describe
intra-mathematical connections and meaning learners made when solving
trigonometric equations. Data were collected through observations, documents and
interviews. During the lessons I was a participant observer, meanwhile documents
accessed were in the form of activities and test. Interviews were semi-structured which
allowed me to get more information about the intra-mathematical connections learners
made and how they affected them when solving trigonometric equations. Data were
analysed thematically. The findings showed that learners made intra-mathematical
connections of procedural, different representations, part-whole and meaning type. It
was also found that the type of intra-mathematical connections learners made in their
solution process allowed most of them to follow appropriate procedures, for
visualisation of the trigonometric equations and determine solutions as angles in
specific intervals. Therefore, the study recommends that the understanding of
mathematical concepts can be developed through the skill of making mathematical
connections which are highlighted by a network of nodes and links represented by
mathematical topics and concepts
The awareness and perception of sorting municipal solid waste : a case study of Lebowakgomo Zone A and F, Lepelle-Nkumpi Local Municipality, Limpopo Province
Get PDFThesis (M.Sc. (Geography)) -- University of Limpopo, 2023Sorting of waste at source is a process where the user is involved in the waste management system that contributes to waste separation. The Municipal Solid Waste (MSW) generated in households need to be sorted to improve sustainable waste management. This study addresses the awareness and perception of sorting municipal waste in Lebowakgomo Zone A and F, Lepelle-Nkumpi Local Municipality. The objectives of the study were to: assess the willingness of householders in sorting Municipal Solid Waste at households’ level before collection services in Lebowakgomo Zone A and F; investigate the socio-economic and environmental impacts of sorting solid waste at source in Lebowakgomo Zone A and F; ascertain the challenges faced during recycling of unseparated solid waste in Lebowakgomo Zone A and F and examine the strategies of Lepelle-Nkumpi Local Municipality on encouraging source separation at Lebowakgomo Zone A and F. The study used a mixed method research approach. The sample size for Lebowakgomo Zone A was 280 and for Lebowakgomo Zone F was 192. The data was collected using open and closed-ended questionnaires, key informant interviews and field observation. The data was analysed using the Statistical Package for the Social Sciences (SPSS) Software version 27. The analysed data was presented in the form of tables, pie charts, bar graphs, and thematic paragraphs. The findings of this research show that the households are willing to sort waste before collection services. There are, however, challenges of waste collection in the two sections. The socio-economic and environmental impacts in Lebowakgomo Zone A and F are creation of jobs, and community participation while there is littering and pollution from waste that is not collected properly. The storage of waste is lacking especially when waste is to be sorted firstly before recycling. Lepelle -Nkumpi Local Municipality is working with the communities to separate their waste. The environmental campaigns need to be established in communities to empower people with knowledge. Environmental education and awareness should be introduced in communities by Lepelle-Nkumpi Local Municipality
The role of municipal public accounts committee in enhancing accountability and municipal performance in Fetakgomo Tubatse Local Municipality
No full textThesis (MPAM.) -- University of Limpopo, 2023This mixed-methods case study examined the role of the Municipal Public Finance Committee (MPAC) in enhancing accountability and municipal performance in Fetakgomo Tubatse Local Municipality. The primary objective of this study was to gain insight into the establishment of MPACs and the state of accountability and performance in the municipality and the effectiveness with which MPACs are able to enhance accountability by municipal officials. Purposive and convenience sampling strategies were used to select eight MPAC members and fifteen councillors from whom qualitative and quantitative research data were collected using anonymised semi-structured questionnaires. Findings indicate that MPACs are adequately established in the municipality and play a critical role in ensuring oversight of municipal council compliance with requisite public finance guidelines in the delivery of services and ensuring that the municipal council adopts and implements resolutions made by the MPAC and Auditor-General. However, MPAC's independence, skill capacity and staffing shortages, as well as the culture of unaccountability and subtle reluctance on the part of the municipal council to uphold and implement its recommendations are major challenges that thwart MPAC's role in ensuring accountability and municipal performance. These findings contribute to the knowledge gaps related to the establishment, roles, challenges, and effectiveness of MPACs in conducting internal oversight activities in local municipalities
Review of extreme value theory with application to the Johannesburg Stock Exchange financial market data
Get PDFThesis (M.Sc. (Statistics)) -- University of Limpopo, 2023The financial sector is vital to the economy as it encourages economic growth.
Therefore, modelling the extremes and risk management of financial stock returns
and losses is vital to economic survival. However, with limited amount
of information it can be difficult to estimate the parameters of the distributions
due to the enormous variance and heavy tails of the financial stock returns.
The problem of limited amount of information has inspired the present
study to examine and model the extreme value behaviour of the Johannesburg
Stock Exchange (JSE) financial market data using the extreme value theory
(EVT). The study employed secondary data acquired from the JSE in South
Africa, which comprises the daily total return index of the All-Share Index
(ALSI) as well as the daily USD/ZAR exchange rates. The generalised extreme
value distribution (GEVD), r-largest order statistics GEVD (rGEVD), generalised
Pareto distribution (GPD), and the Poisson point process along with the
newly proposed alternative for GEVD called blended GEVD (bGEVD) models
were applied to the five-year daily JSE financial market data. The parent distribution
of the maximum daily JSE financial market data was investigated
and the Gamma distribution was found to be the optimal parent distribution.
The block maxima method was employed in the study to fit the EVT models.
The GEVD models for the USD/ZAR exchange rate and the All Share Total
Return Index (ALSTRI) were developed using the weekly and monthly block
maxima method. Both results of weekly and monthly maxima GEVD and the
monthly rGEVD models for the ALSTRI and the USD/ZAR exchange rate can
be modelled by the Weibull and/or Gumbel family. The 100-year return levels of the monthly GEVD, bGEVD, and rGEVD models are almost equal to the
maximum observations of the financial markets, revealing that the ALSTRI
and USD/ZAR exchange rates will exceed 10802 and R18.89 respectively, at
least once in 100 years. The Poisson point process return level estimates are
quite comparable with the GPD estimates, indicating that the ALSTRI and
USD/ZAR exchange rates will surpass 17501.63 and R23.72 respectively, at
least once in 100 years. This implies that the investors will experience higher
gains in the total returns of the ALSI. The USD/ZAR exchange rate return levels
suggest that the Rand will become more unstable in the long run. Instead
of focusing merely on the traditional methods of block maxima, the use of advanced
extreme value methods that accommodate even small datasets such
as GPD, r-largest order statistics, bGEVD, and Poisson point process are encouraged.
The researcher discovered that there are no studies conducted on
bGEVD in the field of finance or financial markets. In the future, more studies
on bGEVD, vine copulas, and r-largest order bGEVD can be conducted on the
financial markets and/or finance sector. Therefore, the present study will add
value to the literature and knowledge of statistics and econometrics
Mainstream educator's and attitudes in implementing inclusive education in the Seshego Circuit, Capricorn South District, Limpopo Province, South Africa
No full textThesis (M.Ed. (Curriculum Studies)) -- University of Limpopo, 2024The role of an educator in implementing inclusive education remains crucial in providing schooling opportunities that are inclusive of every learner in South Africa. The knowledge and attitudes of educators are vital resources for meeting the goals of the White Paper 6. This study explored educators’ knowledge of and attitudes towards the implementation of inclusive education in the Seshego District, Limpopo Province. Qualitative in approach, the study applied a case study design and collected data from ten educators through semi-structured interviews. Document analysis was also used to collect data. The results of the study indicated that there was a rudimentary understanding of inclusive education among educators, conflicting definitions and misconceptions about inclusive education were observed, challenges such as shortage of trained staff, lack of awareness, and inadequate resources, no alignment with global issues regarding the implementation of inclusive education, overwhelming experiences due to a lack of awareness, training, and support, which impacted their effectiveness; nevertheless, the educators did not indicate negative attitudes towards inclusive education despite the challenges, and the educators expressed a lack of confidence in their knowledge about inclusive education policies. The results, therefore, imply that the there is a need for comprehensive and standardized training for educators to enhance their understanding of inclusive education. Furthermore, policy implementation should consider the impact of geographical differences in students’ needs and experiences; support and intervention platforms for educators should be provided, including district resources to mitigate negative experiences and improve overall effectiveness. Policymakers should prioritize teacher education in inclusive practices by providing financial support and necessary teaching materials. Ongoing research and evaluation are essential to adapt policies and practices to the evolving needs of inclusive education by the Department of Education
The relationship between body surveillance, body esteem, self-esteem and eating behaviour among black male university students
Get PDFThesis (M.A. (Psychology)) -- University of Limpopo, 2023Body surveillance is increasing among South African men and is associated with
behaviours that threaten physical health, such as eating behaviours, low self-esteem
and body esteem. Although research has been conducted on the relationship
between body surveillance, self-esteem, body esteem and eating behaviours, there
is a paucity of research on the moderator roles of body- and self-esteem in the
relationship between men’s body surveillance and eating behaviour in Limpopo. A
quantitative study was conducted with a sample of 203 male university students from
the University of Limpopo to examine the relationships between body surveillance,
self-esteem, body esteem and eating behaviours. The Eating Choices Index did not
correlate with any variable. Age only correlated with body esteem, and the Revised
Restraint Scale only correlated with its subscales. Following that, further analysis
was conducted to predict self-esteem and body esteem from body surveillance. The
overall predictive models for both self-esteem and body esteem were statistically
significant, but they showed that amount of variance explained was miniscule. It is
recommended that scales used must be subjected to validation
An investigation of the relationship between english texting proficiency and spelling competency : a case of grade 10 learners at Mafolofolo High School in Limpopo Province, South Africa
Get PDFThesis (Ph.D. (English Studies)) -- University of Limpopo, 2024The purpose of the study was to investigate the relationship between English texting proficiency and spelling competency. In line with the assumed positivist stance, a quantitative approach was adopted for the investigation. A quasi-experiment research design was used to determine how the independent variable (texting proficiency) exerted influence on the dependent variable (spelling competency). A purposive sampling technique was employed to sample 92 Grade 10 learners to participate in the study. A preliminary questionnaire was administered to solicit information about the learners’ cell phone ownership and text messaging behaviour and tendencies. The gathered information was used to further demarcate the sample into Experiment and Control groups. The Experiment group comprised learners who owned a smart phone and participated in text messaging, while learners who did not own a cell phone and were not actively involved in text messaging were assigned to the Control group. A translation task, a textism reading task, a dictation exercise, and a creative writing test were administered as data collection strategies for the study. The sets of qualitative data collected through the four data collection instruments were analysed separately using checklists outlining specific criteria applied as measures of the participants’ levels of spelling proficiency. The results of the study revealed an existence of positive relationship between textism proficiency and spelling competency. Participants who were exposed to text messaging emerged as better spellers than respondents with restricted exposure to and activity in text messaging. Furthermore, female participants were proven to be more spelling-savvy than their male counterparts. The study recommends a perceptual shift in terms of how text messaging is regarded, in order to facilitate its acknowledgement and appreciation as a vital facilitative tool in formal language teaching and learnin
Entrepreneurial orientation and the performance of Small, Medium and Micro Enterprises in selected Municipalities of Limpopo Province: the role of market orientation and environmetal dynamism
Get PDFThesis (M. COM. (Business Management)) -- University of Limpopo, 2023A growing number of recent studies highlight an avenue of entrepreneurial orientation. Previous studies have examined the relationship between entrepreneurial orientation (EO) and performance (P) and and various mechanisms are intergarated in the relationship. The studies reveal inconsistent results, probably due to the omission of the mediating and moderating roles of market orienatation (MO) and environemental dynamism (ED). To explicitly address this gap, this study investigates how EO influences performance in selected municipalities of Limpopo Province: the role of MO and ED. The data was collected form 403 respondents across Capricorn and Sekhukhune Municipalities. The data was analysed using SmartPLS 4.0. The empirical findings of this study show that there is a significant positive relationship between EO and the performance of SMMEs. The study further shows that the relationship between EO and performance is partially mediated by MO and the relationship is also moderated by ED at an average weight. The contributions of this study are (i) that it unravels EO as a uni-dimesional construct and the effect it has on performance. The second contribution is assessing the roles of mediating and moderating variables that influence the EO-performance nexus. This paper fills a gap in the literature by exploring external business variables mediating and moderating the relationship between EO and performance and contributes to the discussion on the contradictory results regarding the relationship between EO and performanc