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Assessing impacts of climate changes extremes and land use/land cover changes on surface water quality in Letaba Catchment, South Africa
Get PDFThesis (M.Sc. (Geography)) -- University of Limpopo, 2024Water, a fundamental resource, plays a crucial role in human prosperity, and its relationship with climate dynamics and land use patterns is critical, particularly in semi-arid regions. This study assesses the impact of climate change and land-use/land-cover (LULC) changes on surface water quality within the Letaba Catchment. Remote sensing and GIS techniques provided valuable insights into land use changes, showcasing the effectiveness of the Random Forest classifier algorithm. The analysis of precipitation patterns over three key years (1986, 1994, and 2018) reveals substantial variations, uncovering the localised nature of rainfall influenced by geographical factors. The transition from 1986 to 1994 revealed noteworthy shifts, including an increase in forestry (6% to 13%) and built-up areas (11% to 12%), while water bodies experienced a significant reduction from 13% to 5%. The subsequent leap to 2018 continued this transformation, with further decreases in water bodies, forestry, and vegetation, and notable expansions in built-up areas, cultivated land, and barren land. This analysis showed the impacts of both natural processes and anthropogenic developments on the Letaba catchment's landscape. Examining surface water quality parameters, the study revealed a concerning decline in pH levels in 2018, indicating acidity and suggesting potential implications for aquatic life. Despite this, phosphorus, and Chemical Oxygen Demand (COD) levels adhered to acceptable standards, emphasizing the ecosystem's resilience to maintain nutrient balance. The analysis of the complex interaction between rainfall, LULC changes, and surface water quality parameters revelled intriguing insights. For the years 1986, 1994, and 2018, no significant connection was observed between electrical conductivity and rainfall. The examination of non-linear connections, crucial in understanding the impacts of LULC changes on the dynamics of surface water quality, highlighted the nuanced relationships captured through Spearman rank correlation. This study provides important analysis into the evolving surface water quality parameters of the Letaba Catchment, emphasising the impact of temporal dynamics, climate, and anthropogenic impacts on landscape and surface water quality.Water Research Commission (WRC
Fabrication of functionalised-MWCNTS/metal chalcogenides composite non-enzymatic electrochemical sensor for the the detection of glucose
Get PDFThesis (M.Sc. (Chemistry)) -- University of Limpopo, 2024One of the most significant analysis in medical diagnosis is blood glucose measurement. In other scientific and industrial domains, such as environmental monitoring, pharmaceuticals, and the food sector, they are equally indispensable, however commercial glucometers that are sold on the market frequently have a lot of flaws and limits. These can be caused by a variety of challenges, such as poor material design, incorrect storage, coding mistakes, issues with device calibration, manufacturing processes, and the substantial influence of ambient elements like pH and temperature. Some of these issues might be resolved by creating brand-new hybrid materials with enhanced characteristics (such stability and adsorption capabilities). The metal sulfide-decorated-functionalised-multi-walled carbon nanotube modified non-enzymatic glucose detecting sensor was studied. Many physicochemical and structural investigations, such as Fourier transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Raman spectroscopy, were performed to characterize the synthesized nanocomposites. Electrochemical methods such as square wave voltammetry, cyclic voltammetry, and electrochemical impedance spectroscopy were used to comprehensively test the produced sensors. The p-MWCNTs were purified and functionalised by acid treatment into COOH-MWCNTs. Amine functionalise MWCNTs (NH2-MWCNTs) were donated by Mintek. Metal sulfides nanoparticles (FeS2 and ZnS) were synthesised using hydrothermal method under the same experimental conditions as the metal sulfides/f-MWCNTs nanocomposites for comparison in the electrochemical studies. Fourier transform infrared spectroscopy (FTIR) verified that carboxyl (COOH) and amine (NH2) functional groups were detected on the surface of the f-MWCNTs, which appeared at lower wavenumbers, i.e., below the fingerprint due to the presence of metal sulfides. Transmission electron microscopy (TEM) was used to confirm that FeS2 and ZnS nanoparticles successfully decorated MWCNTs in situ. The functionalized MWCNTs surface exhibited a well-dispersed distribution of metal sulfides, as demonstrated by TEM pictures. X-ray diffraction (XRD) was used to confirm the chemical composition of the as-prepared MWCNTs, indicating the existence of MWCNTs and metal sulfides. The XRD pattern of FeS2/COOH-MWCNTs nanocomposites represented crystal planes of pyrite FeS2. The ZnS/COOH-MWCNTs nanocomposites' XRD pattern agrees with published data and confirms that ZnS forms in the cubic (sphalerite) phase with acceptable crystallinity. The Raman spectra of pristine MWCNTs, COOH-MWCNTs, FeS2/COOH-MWCNTs, FeS2/NH2-MWCNTs ZnS/COOH-MWCNTs and ZnS/NH2-MWCNTs all showed three vibration bands namely, D, G, and G’, further confirming the presence of the carbonous nature of the MWCNTs. The electrochemical characteristics of the nanocomposites formed by metal sulfides/functionalized-MWCNTs were investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). These analyses were performed in a solution containing 5 mM K3Fe(CN)6 /K4Fe(CN)6 as the redox probe and 0.1 M KCl as the supporting electrolyte. The resultant nanomaterials had redox active groups that produced a signal on the electrode surface, and these groups could be used to build electrochemical sensors and biosensors. The cyclic voltammograms illustrate the comparative current in this decreasing order: ZnS/COOH-MWCNTs-GCE> FeS2-GCE> p-MWCNTs-GCE> BARE-GCE> ZnS/NH2-MWCNTs-GCE> FeS2/NH2-MWCNTs-GCE> GCE-ZnS-GCE˃ GCE-COOH-MWCNTs-GCE> FeS2/COOH-MWCNTs-GCE˃ NH2-MWCNTs-GCE.
The fitted impedance data reveals that the GCE-ZnS/COOH-MWCNTs electrode has the lowest Rct value of 33 Ω, proposing a swift electron transfer of the GCE-ZnS/COOH-MWCNTs electrode as in comparison to the remaining electrodes, consistent with the findings from cyclic voltammetry. Consequently, the ZnS/COOH-MWCNTs nanocomposite showed better electroactivity and great potential to be employed for glucose detection. Square wave voltammetry (SWV) was used for the electroanalysis of the analyte (glucose) at the GCE-ZnS/COOH-MWCNTs. The results showed that the GCE-ZnS/COOH-MWCNTs had better electrocatalytic behaviour resulting from the higher oxidation peak currents (Ipa) and faster electron transport. The results from scan rate studies demonstrate that the scan rate (v) correlates directly with the glucose anodic current responses (Ipa) at GCE-ZnS/COOH-MWCNTs. The glucose oxidation mechanism at GCE-ZnS/COOH-MWCNTs was diffusion-controlled, indicated by the linear relationship observed between oxidation peak currents (Ipa) and the square root of the scan rate (v1/2). Employing square wave voltammetry, a limit of detection (LoD) of 0.83 mM was achieved for GCE-ZnS/COOH-MWCNTs within alinear dynamic range (LDR) of 1-9 mM. The sensitivity of the sensor was measured at 7.2 x 106 A.mM-1
Evaluation of corrosion inhibition effect of glycerol stearate on aluminium metal by electrochemical techniques
Get PDFJournal article published in the Arabian Journal of Chemistry (2023) 16, 104798The inhibitory effect of glycerol stearate (GS) on aluminium (Al) metal was examined
utilizing weight loss, potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy
(EIS) in hydrochloric acid (HCl) solution. Gravimetric analysis, PDP, and impedance
spectroscopy were used to calculate the rate of corrosion (EIS). Gravimetric measurement and electrochemical
methods both demonstrated that when the inhibitor concentration increased, the corrosion
rate decreased. PDP and EIS inhibition effectiveness was best at 50 10-5 mol. L-1 glycerol
stearate concentration,with 81.1% and 86.1%, respectively. The differences in corrosion potential
(Ecorr) values between the blank and inhibitor (GS) concentrations revealed that glycerol stearate
acted as a mixed type of corrosion inhibitor. The inhibitors’ adsorption on the aluminium surface
followed the Langmuir isotherm model. Fourier transform infrared spectroscopy (FTIR) indicated
the existence of an adsorption coating on the surface of the aluminium metal. SEM pictures of aluminium
demonstrated decreased inhomogeneities in the presence of glycerol stearate
Effect of dietary citric acid supplementation & use of non-linear models on growth performance in Venda chickens
Get PDFThesis (M.Sc. (Animal Production)) -- University of Limpopo, 2023The development curve of Venda chicken fed with various amounts of citric acid was
evaluated using nonlinear models in an experiment. to ascertain the effects of citric
acid supplementation level on feed intake, body weight increase, and linear
measurements on Venda chickens. 200 male Venda chickens were used in the
experiment which lasted 90 days. The chicks were randomly assigned to four
treatments (0, 12.5, 25 and 50g of citric acid inclusion) with 5 replications, resulting
in 20 floor pens with 10 chicks per replicate. A completely randomized design was
employed as experimental design. Analysis of Variance (ANOVA) was used to
determine the effect of citric acid on feed intake, body weight gain, FCR, GR and
body linear measurements. Three different non-linear models, namely Gompertz,
Weibull, and Richards, were used to define the growth curves of the Venda chickens.
The Duncan multiple range test at the 5% level of significance was utilized to detect
significant differences between the means. Models were compared using coefficients
of determination (R2) and standard errors (SE). The results indicated that feed
intake, body weight, average daily gain and growth rate of Venda chickens were not
affected (p > 0.05) by citric acid supplementation levels. Similarly, Citric acid
supplementation had no effects (p > 0.05) on the shank length and wing length of
Venda chickens. However, feed conversion ratio (FCR) of Venda chickens was
improved (p < 0.05) by with an increase in citric acid supplementation. The Venda
chicken fed citric acid at grower phase and finisher phase had better growth
performances than the starter phase. Citric acid supplementation improved the back
length and thigh length of Venda chickens. The Venda chickens fed citric acid at 25g
inclusion level significantly higher back and thigh length. The coefficient of determination ranged from 0.00 to 0.98 in all the treatments. The Gompertz Model and Richards Models both exhibited the same coefficient of determination across all treatments. The model with the lowest standard error was found to best describe the growth curve of male Venda across all treatments. The Gompertz model was observed to be suitable for explaining the growth of Venda chickens fed with feed without citric acid (CA0g) and citric acid 125g inclusion (CA12.5g). The Richards model was observed to be suitable for explaining the growth of Venda chickens fed citric acid 25g inclusion (CA25g) and citric acid 50g inclusion (CA50g). It is recommended to use a supplement containing lower citric acid to enhance the body linear measurements and growth performance of the chickens. Gompertz and Richards models can be utilized to characterize the growth curve of Venda chickens.National Research Foundation (NRF
Modelling willingness to pay for genetically modified Tela BT maize seed technology in Mpumalanga Province, South Africa
Get PDFThesis (M.Sc. Agriculture (Agricultural Economics)) -- University of Limpopo, 2023Maize (zea maize) is the most important crop in South African grain production, providing nutrients to both humans and animals. It is a basic raw material for producing fuel, starch, oil and alcoholic beverages, as well as other economic benefits such as high yields and high income. Smallholder households have great reliance on agriculture that has shown little productivity improvement over a long period of time. This slow agricultural progression is largely attributed to a relatively low adoption and use of improved technologies, including hybrid seeds and fertilizers. The GM technology has been identified as one of the solutions to prevalent issues of food inadequacy brought about by population growth and dissatisfactory food production by people living in less developed countries.
This study aimed at modelling willingness to pay (WTP) for genetically modified TELA® Bt maize seed technology in Mpumalanga Province, South Africa. The objectives of the study were to: profile socio-economic characteristics of smallholder maize farmers in
Mpumalanga Province, assess farmers’ knowledge, attitudes, perceptions, and practices (KAPP) towards the TELA® Bt maize seed technology in Mpumalanga Province, South
Africa, determine smallholder maize farmers’ WTP for the TELA® Bt maize seed technology in Mpumalanga Province, South Africa and analyse the determinant factors influencing smallholder maize farmers’ WTP for TELA® Bt maize seed technology in Mpumalanga Province. Data was collected from 289 farmers using purposive and multistage sampling techniques for the TELA® Bt maize, and snowball sampling techniques for the non-TELA® Bt maize farmers
The descriptive statistics, which included cross tabulations and frequency distributions were used to describe socioeconomic characteristics of smallholder maize farmers and their typology, which addressed the first objective of the study. To address the second objective of the study, the Likert-scale and descriptive statistics were used to assess farmers’ knowledge, attitudes, perceptions, and practice (KAPP) towards the TELA® Bt maize seed technology in the study area concerned. A discrete choice experiment was deployed to solicit and compute the mean willingness to pay (MWTP) from the farmers,
and finally, the Logistic regression model was used to identify determinant factors significant towards WTP for TELA® Bt maize seed technology.
The results from the Logit scale for parameter estimates used to compute the mean willingness to pay (MWTP) showed that the additional amount farmers were willing to pay for a 1 kg bag of the TELA Bt maize seed technology was R6.59. The Logistic regression model empirical results showed that among farmers who were willing to pay for the TELA® Bt maize technology, household size, access to extension services, health perception, trust in government and benefits perception had a significant impact in their WTP.
In light of the research findings, several policy suggestions were made that there should be a concerted effort from the side of the government to ensure frequent exposure of farmers to extension services. It also calls for the private institutions and NGOs responsible for the introduction of GM technology to work cohesively with the members of the public and the media to help facilitate the dissemination of relevant information about GM crops.(ARC) Agriculture Research Council
AAT
The pretext of identity crisis in Post-Colonial Africa : a study of selected Novels of Kopano Matlwa
Get PDFThesis (M.A. (English Studies)) -- University Limpopo, 2023This study has sought to explore the pretexts of identity crisis in post-colonial (South) Africa through the prism of Kopano Matlwa`s novels. It has used a qualitative research design to dissect the pretext of identity crisis in post-colonial (South) Africa unveiled in Matlwa’s novels through a textual analysis approach. The literature review section centred on the following themes: identity, colonialism and colonisation, pre-colonial, post-colonial, African, feminism, womanism, and Afrocentricity. Moreover, the findings from Matlwa’s novels revealed that the African-born free generation can resolve this identity crisis by reclaiming their roots and identity, and by going back into their past to identify with their African culture and traditions, where their roots come from which are linked to the African names and surnames. The majority of the characteristics in these novels are influenced by Western stereotypes and behaviours, and this resulted in a crisis as the African identity becomes left behind if not following, mimicking and experiencing a hybrid western identity
Educational testing techniques in senior secondary school physics in Nigeria : are we ascertaining the development of requisite behavioural objectives?
Get PDFJournal article published in African Perspectives of Research in Teaching & Learning Journal (APORTAL) Vol 7 (1) (2023)In order to estimate exam question demands and distributions in senior secondary school physics, this study was conducted. For the determination of the types of tasks involved, quantitative and qualitative research methods were combined (mixed method). Using Bloom’s taxonomy of educational objectives, content analysis was carried out on questions from West African Examination (WAEC) and University of Cambridge International Examination. A perceptual Rating Scale (PRS) with a reliability coefficient of 0.89 was used to determine the readability indices of the questions. Detailed information on the subject matter was gathered through an in-depth interview of two students who sat for the two examinations in the year 2021. Analysis of the data obtained was conducted using inductive thematic analysis and descriptive statistics. Bloom's taxonomy revealed that most questions were related to the lower levels (remembering and understanding), but no or very few questions were related to the higher levels. These outcomes portend far-reaching implications for the overall goals of teaching physics. It was therefore recommended that besides scaling up the training for inspectorate officers in the Ministry of Education, it is highly imperative for critical stakeholders and examination bodies, in particular, to promote questions along higher-order cognitive level
Enhanced creativity with Mini-PAT : a case of grade 9 technology teachers in Sekhukhune East
Get PDFJournal article published in African Perspectives of Research in Teaching & Learning Journal (APORTAL) Vol 7 (1) (2023)Creativity has become a prerequisite for societal progress, and schools are critical to this progress. The purpose of this study was to explore Grade 9 Technology teachers’ creative pedagogy when handing Mini-PAT in schools around Sekhukhune East district. Qualitative research design was employed by the researcher to purposively sample five (5) Technology teachers from five (5) schools to participate in this study. Non-participant observations and semi-structure interviews were used as the methods of data collection from the participants. This study adopted Rashmi’s four elemental model of creative pedagogy as a conceptual framework. The findings of this study have revealed that grade 9 Technology teachers have challenges in engaging their creative pedagogy when handling Mini-PAT and that hinders the promotion of creativity. These challenges are some of the reasons why the purpose of Technology of producing creative learners is not obtained. This study calls for the Department of Basic Education to revamp the curriculum for Technology education, especially as it concerns time allocation for a smooth incorporation of creativity in the classroom. It also encourages subject advisors to come with better ways of training teachers on how to apply their creative pedagogies and the design process when handling Mini-PAT. Lastly, it encourages Technology teachers to reflect on their teaching strategies with respect to creative thinking skill
“Pathetic Scholarship” In Gukurahundi and related studies: a silver lining from social media cloud
Get PDFJournal article published in African Perspectives of Research in Teaching & Learning (APORTAL) Vol 7 (2) (2023)“In every dark cloud, there is a silver lining”.
In this context, the perceived prevalence of pathetic scholarship in Gukurahundi studies and
other cognate fields is cause for concern among scholars and practitioners. However, pathetic
scholarship is not uniformly understood by interested parties, who largely base their arguments
on Euro-American perspectives that only provide a partial understanding of this phenomenon.
Against this backdrop, this paper seeks to critique pathetic scholarship, whether real or
imagined, in Gukurahundi Studies, Media, Politics, Conflict, and Peace Studies, just to mention
a few. For this paper, pathetic scholarship is understood as studies of sub-standard in terms of
set criteria. Methodologically, this paper employs conversations and interdisciplinary discourse
analysis with an alternative Afrocentric approach. In this paper, it is argued that pathetic
scholarship has not yet reached a crisis point. In fact, pathetic scholarship (in its current form)
carries the hopes and aspirations for interdisciplinary richness in tackling difficult subjects such
as Gukurahundi and apartheid
Teacher quality is a defining factor of student academic performance in schools : the case of a district in South Africa
Get PDFJournal article published in African Perspectives of Research in Teaching & Learning (APORTAL Vol. 7 (3) (2023)There does not seem to be a singular, all-defining factor justifying the poor performance of students across the globe, but what is indisputable is that many scholars have attributed the poor performance of students to teacher quality. This suggests a clear correlation between teacher quality and student performance. The researcher implemented a contingency theory that centres on creating a relationship between schooling processes and outcomes. An ethnographic design grounded in the interpretative paradigm and premised on the qualitative research approach was adopted to explore how societies and individuals function in their natural environment to facilitate learning. Through purposive sampling, 12 participants were drawn from two local municipalities in a district of South Africa to take part in individual interviews. The analysis was done
concurrently using ATLAS ti and thematic analysis. The findings suggest that claims of the
impact of teacher quality on students’ academic performance are indeed not overemphasised. However, they also show a systematic correlation between learner performance and teacher professional development rather than teacher quality alone. The study concludes that stakeholders must take full responsibility for learning by making holistic efforts towards teacher development and professionalism which are vital as long as teaching and learning remain an evolving practice