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Item 2,2-Dithiobis(benzothiazole) complexes (Cd and Ni): Precursors to nanoparticles and electrochemical properties and interactions with Rhodamine B(Vaal University of Technology, 2021-10-13) Mabaso, Busisiwe Dagracia; Moloto, N., Prof.; Moloto, M. J., Prof.The ligand 2, 2-dithiobisbenzothiazole and it metal complexes have been a subject of interest in various fields but they have found to exhibit remarkable and prevalent biological and pharmacological activities. The ligand tends to coordinate to complexes through the sulfur atom and hence the metal-sulphide bond are good precursor to generate metal sulfide nanoparticles using single-source precursor route. The complexes are generally prepared by reflux for 1 to 2 hours depending on the solvent used to produce very stable solid products and some form in crystalline form. All the prepared nickel and cadmium complexes were characterized using techniques such as elemental analyzer, IR, 13C NMR spectroscopy and thermogravimatric analysis. The data obtained from the spectroscopic analysis was consistent of the coordination of the ligand with the metal ions through the sulphur atoms of the 2,2-dithiobisbenzothiazole moiety. The thermal analysis of the prepared complexes gave a final residue of metal sulphide for both metal complexes. Characterization techniques showed the formation of bidentate complexes for both nickel complex and cadmium complex. The prepared complexes were then used to synthesize metal sulphide nanoparticles .The nanoparticles were prepared by thermal decomposition method of the single source precursor in a solution of oleylamine (OLA). Two different parameters were investigated temperature and time to study their effect on the size and shape of the nanoparticles. The synthesized nanoparticles were characterized using techniques such as UV-Vis spectroscopy, photoluminescence spectroscopy, and X-ray diffraction analysis and transmission electron microscopy. The temperatures of the reaction have a significant effect on the rate of the reaction that will affect the size and shape of the nanoparticles. This effect was confirmed by the optical properties of the synthesized nanoparticles prepared at different reaction temperatures. The spectra shows that absorption maximum and band edge shift to lower wavelength as the temperature of reaction was progressively increased. This trend is associated to the decrease in particles size of the prepared nanoparticles. TEM images further confirmed that the particles size of the prepared nanoparticles was progressively decreased as the temperature was increased. The time of the reaction is one of the most significant factors in the synthesis of the nanoparticles. The investigation of the time of the reaction yield results that depicted that with increase in time of the reaction, the band edge increases, but relatively at short wavelength to the bulk. Hence, the band edges of the nanoparticles were blue shifted significantly to the bulk. The results show that with an increase in the time of the reaction, the nanoparticles increases in their size due to Ostwald ripening. The optimum complexes and optimum nanoparticles were used to further study their electrochemical properties using cyclic voltammetry and electrochemical impedance spectroscopy (EIS) graphs were fitted using the randles circuit and they confirm that the NiS nanoparticles GCE greatly increase the electron transfer rate, probably due to the nanostructured surface property of the NiS nanoparticles. Differential pulse voltammetry (DPV) was used to study the electrochemical behavior and the DPV showed that the current response of Rhb was higher for the optimum temperature NiS nanoparticles compared to all the materials used. There was an increase in the Rhb current response with an increase in pH and pH 7 was used as the optimum pH when Ni- complex was used as a modifier and pH 8 was used as optimum when NiS nanoparticles were used as a modifier. Effect of concentration showed that the NiS nanoparticles for the optimum temperature had a wide linear range and a low detection limit. The method has good accuracy, acceptable precision, and reproducibility. This method provides a novel electrochemical method for determination of RhB.Item Acceptance of biometric authentication security technology on mobile devices(Vaal University of Technology, 2022) Malatji, W. R.; Van Eck, Rene, Dr.; Zuva, Tranos, Prof.Mobile devices are rapidly becoming a key computing platform, transforming how people access business and personal information. Accessing business and personal data using mobile devices requires authentication that is secure. The world is rapidly becoming connected and all users of mobile devices need to be clear regarding individual data security. As a result, biometrics for mobile devices has come into existence. Biometric technology can be applied on mobile devices to improve the trustworthiness of wireless services. Furthermore, it is of great importance and necessary to start paying attention to and investing in mobile biometric technologies, as they are quickly turning into tools of choice for productivity. In the literature review, it shows that few studies measured the acceptance of biometric authentication technology on mobile devices. This study seeks to find out the perceptions as to the acceptance of biometric authentication technology on mobile devices. TAM2 was used as the foundation for generating the hypothesis and developing the conceptual framework for this study. This quantitative study used a survey-based questionnaire to collect data from 305 participants. The simple random sampling technique was used to select participants for this study. The response rate was 98% of the expected population, which was a total of 302 valid responses. A descriptive analysis was deployed to provide a description of respondents’ demographic characteristics. SPSS was used to compute the multiple regressions in order to evaluate the research hypotheses. The findings of this study revealed that perceived humanness, perceived interactivity, perceived social presence, perceived ease of use and subjective social norm, and perceived usefulness and trust are important determinants of customers’ intention to accept and use mobile biometric devices. It was found that reliability is a good predictor of trust. On the other hand privacy, identity theft and combining data are also important determinants of trust. This work can be used to strengthen biometric authentication technology in-cooperation with mobile devices for simplicity of use. Since most mobile devices are used for personal and business information, further research on the acceptance of biometric authentication technology on mobile devices is needed.Item Adoption of mobile learning at the University of Technology in South Africa(Vaal University of Technology, 2019-11-29) Hlatshwayo, Motsotua Confidence; Baxter, Roger; Zuva, Tranos, Prof.The influence of Information and Communication Technology (ICT) in the education system has encouraged both students and educators to become more and more computer literate. With the increased use of portable devices (tablets, PDAs, Smartphones, iPads etc.), mobile learning (m-learning) has gained popularity as it is believed to be an effective and efficient tool for content presentation and knowledge acquisition in education sector. The realisation of the benefits depends on the effective adoption of m-learning technology. The superseding purpose of this study was to investigate the adoption of mobile learning at a University of Technology (UoT) in South Africa. A quantitative study was carried out at an UoT in South Africa, with respect to mobile learning perceptions; 64 valid questionnaires were received from the participants. The proposed research framework/model derived from Extended Technology Acceptance Model (ETAM) and Technology Acceptance Model 3 (TAM3) was used. The Statistical Package for the Social Sciences (SPSS), version 25.0. was used for analysing data. The findings revealed that perceived usefulness of mobile learning, attitude toward mobile learning, service and system quality as well as perceived ease of use are significant predictors of intention to use mobile learning application. Perceived mobility on mobile learning strongly influences perceived usefulness more than perceived ease of use of mobile learning application. The study concluded that it is necessary to measure perception of potential users using the variables in the model proposed before adoption of mobile learning application to ascertain an effective adoption of the technology in education.Item Adsorption of Cr(VI) by iron oxide functionalized polyethyleneimine (PEI) coated activated carbon-silica composites(Vaal University of Technology, 2020-12-14) Qhubu, Mpho Cynthia; Nomngongo, P. N., Prof.; Pakade, V. E., Prof.Water scarcity due to limited resources and pollution of the little available water by organic and inorganic contaminants remains as one of the critical issues of the 21st century. Several treatment methods have been developed, with some being used successfully at industrial scale but many challenges including secondary sludge generation, high operation costs, high maintenance costs and high energy input were observed. In this study, the adsorption process was explored as an effective means for the removal of Cr(VI) ions from aqueous solution due to its economic feasibility and use of abundantly available adsorbents. Amongst the many available adsorbents, this work focused on exploring functionalized activated carbons (ACs) as adsorbents for Cr(VI) ions due to their favorable adsorption characteristics which involve large surface area, high porosity, and high radiant stability. The iron oxide functionalized polyethyleneimine activated carbon-silica composites were prepared through co-precipitation of Fe(II) and Fe(III) over Macadamia activated carbon to form the AC-Fe3O4 co-shell which was reacted with tetraethylorthosilicate (TEOS) and the polyethyleneimine (PEI). The different adsorbents prepared were labelled AC-Fe3O4, AC-Fe3O4-SiO2 and AC-Fe3O4-SiO2-PEI. The adsorbents were further characterized using elemental analysis (CHNS), thermo gravimetric analysis (TGA), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy, Brunauer-Emmett-Teller (BET), transmission electron spectroscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). FTIR displayed successful attachment of Fe3O4 and SiO2 with bands at 404 and 786 cm-1 being assigned to the asymmetric vibration of Fe-O and Si-O-Si while the asymmetric stretch of Si-OH is observed at 1066 cm-1. XRD showed the presence of magnetite particles in the adsorbents confirmed by the JCPDS 00-019-0629. EDS revealed the presence of Fe, Si, and N atoms which can relate to successful incorporation of the desired functional groups. Each of these materials were evaluated for their Cr(VI) ion removal through batch adsorption experiments where one parameter at a time was varied while all others were fixed. The parameters investigated included the effect of pH, contact time, initials Cr(VI) concentration, adsorbent dosage concentration and temperature. The optimum conditions were obtained at pH 3, initial concentration 2.5 mg/L, contact time of 120 min for AC-Fe3O4-SiO2-PEI. The optimization of each parameter was done in order to determine the conditions in which the adsorbents work best in the uptake of Cr(VI). All the three studied adsorbents showed acceptable adsorption performance for the removal of Cr(VI) from aqueous solutions. Adsorption isotherms studied confirmed that the adsorption data in all the three adsorbents fitted well into the Langmuir isotherm, demonstrating a homogeneous monolayer coverage. Regarding the kinetic studies, the adsorption data were best described by the pseudo-second order rate model with R2 values of 0.974, 0.974 and 0.962 for AC-Fe3O4, AC-Fe3O4-SiO2 and AC-Fe3O4-SiO2-PEI, respectively. The adsorption capacity observed from the present study (6.62, 3.92 and 5.48 for AC-Fe3O4, AC-Fe3O4-SiO2 and AC-Fe3O4-SiO2-PEI, respectively) were satisfactory and suitable as compared to those reported in literature. Thermodynamics data of the adsorption processes revealed a feasible spontaneous endothermic adsorption process which also confirmed that the reaction process occurred through chemisorption.Item Adsorption of nitrate and fluoride anions from aqueous solutions using doped magnetite-pinecone nanocomposites(Vaal University of Technology, 2022-03-23) Frans, Nonhlanhla; Ofomaja, A. E., Prof.; Akpotu, S., Dr.; Pholosi, A., Prof.The increasing rate of pollutants, such as nitrate and fluoride from industrial and agricultural sources in the environment, especially in water bodies, is becoming alarming. Excessive nitrate and fluoride concentration in water cause environmental toxicity and hazard such as eutrophication and toxic, chronic illnesses such as methemoglobinemia. Hence, there is an urgent need to remove these pollutants from water. There have been a few successful strategies for the purification of pollutants contaminated water. Adsorption has been applied to remove pollutants from aqueous media due to its flexibility, ease of use, cost-effectiveness and ability to adsorb contaminants at low concentrations. Various adsorbents have been applied to remove nitrate and fluoride anions, and doped magnetic has shown to be effective in removing these anions. In this study, manganese doped magnetite coated pinecone (Mn-MNP-PCP) and lanthanum doped magnetite coated pinecone (La-MNP-PCP) nanocomposite were prepared using the co-precipitation method. Fourier Transform Infra-Red (FT-IR), Scanning electron microscopy (SEM), Energy-dispersive x-ray spectroscopy (EDS), Thermo-gravimetric analysis (TGA), X-ray diffraction (XRD) were used to determine the surface groups, structure and morphology, chemical composition, thermal stability and phase determination (amorphous or crystalline) structure of the synthesised Mn-MNP-PCP and La-MNP-PCP adsorbents, respectively. In addition, batch adsorption experiments were conducted to evaluate the effects of solution pH, adsorbent dose, initial solution concentrations, contact time, adsorption kinetics, adsorption isotherm and the impact of co-existing anions on the adsorption of nitrate and fluoride ions. The mechanism of adsorption processes was also determined using equilibrium isotherm modelling results and thermodynamic parameters. The maximum adsorption capacity of Mn-MNP-PCP and La-MNP-PCP adsorbents for nitrate adsorption was 22.8 mg/g and 37.7 mg/g at solution pH 4, while the adsorption efficiency was 45.6% and 75.4%. Fluoride removal occurred at pH 2 with the adsorption capacity of 46.2 mg/g and 44.77 mg/g with the removal efficiency of 92.4 % and 89.6% on both Mn-MNP-PCP and La-MNP-PCP adsorbents. The optimum adsorbent dose for both Mn-MNP-PCP and La-MNP-PCP in the adsorption of nitrate and fluoride was 1 g/L. The optimum time for the uptake of nitrate and fluoride onto MNP-PCP and La-MNP-PCP was between 15 – 20 min. The competing phosphate and sulphate ions impacted the nitrate adsorption, while the presence of carbonate and chloride had positive nitrate adsorption onto both Mn-MNP-PCP and La-MNP-PCP nanocomposites. The decrease in nitrate adsorption may be attributed to the lower affinity of Mn-MNP-PCP and La-MNP-PCP for nitrate and a competition between the nitrate ions and co-existing anions for the active sites. The presence of all competitive ions decreased the fluoride adsorption onto Mn-MNP-PCP and La-MNP-PCP nanocomposites. The multi-valent anion with higher charge density have been reported to be more readily adsorbed than monovalent anion. The equilibrium data for nitrate and fluoride ions uptake was best described by Langmuir isotherm, which predicts the formation of ionic or covalent chemical bonds between the adsorbent and adsorbate. In the same vein, pseudo-second-order model is considerably suitable for nitrate and fluoride ions adsorption, which showed that their uptake was fast. Conclusively, La-MNP-PCP adsorbent is an effective adsorbent for nitrate adsorption, while Mn-MNP-PCP effectively trmoved fluoride ions from the aqueous solution.Item Adsorption studies of toxic metal ions (Co(II), Ni(II), Cu(II), Cr(VI) and Pb(II)) and methylene blue using black cumin (Nigella sativa L.) seeds(Vaal University of Technology, 2021) Thabede, P. M.; Xaba, T., Dr.; Naidoo, E. B., Prof.; Shooto, N. D., Dr.High levels of pollutants in water are found to have poisonous effects on human health. Due to increasing awareness about the environment and strict environmental regulations, wastewater treatment has become a very important aspect of research. Thus, this makes the adsorption of pollutants an urgent matter. The aim of this research was to investigate the adsorption capacity of black cumin seeds in the removal of cobalt-Co(II), nickel-Ni(II), copper-(II), chromium-Cr(VI), lead-Pb(II), and methylene blue (MB) dye from aqueous solution. In this research work the black cumin seeds were reacted with sodium hydroxide (NaOH), hydrochloric acid (HCl), phosphoric acid (H3PO4), potassium permanganate (KMnO4) and sulfuric acid (H2SO4). Thereafter it was carbonized at 200 and 300 °C and functionalized with magnetite-sucrose nanoparticles and further carbonized at 600 °C to improve the adsorption capacity of the materials towards different pollutants. The seeds were characterized by scanning electron microscopy (SEM), thermogravimetric analyser (TGA), X-ray diffractometer (XRD), Brunauer, Emmett and Teller (BET) and Fourier transformed infrared (FTIR) spectroscopy. The SEM images showed that the surface morphology of the treated adsorbents was more porous and had cavities more than the starting material. The TGA profile showed a major weight loss between 198-487 °C which was due to disintegration of cellulose, lignin and hemicellulose. The XRD spectra of adsorbents showed broad peaks at 2θ value of 21° associated crystalline lignocellulose content. FTIR results showed that the adsorbents had functional groups such as hydroxyl (-OH), carboxyl (-COOH), amide (-NH) and carbonyl (-C=O). The BET surface area of pristine black cumin seeds was 2.7 m2/g and increased after treatment with KMnO4 and H3PO4 to 10.1 and 9.3 m2/g respectively. The surface area of the carbon black cumin seeds was 11.67 m2/g whilst the activation of carbon from black cumin seeds with 10 and 20% H2SO4 gave the surface area of 20.14 and 21.54 m2/g respectively. The seeds activated with 20% H2SO4 showed larger pore width of 7.13 nm compared to 6.81 and 3.78 nm after treatment with 10% H2SO4 and carbon black cumin seeds respectively. The results show that there is an increase in surface area and pore size for both 10 and 20% H2SO4 in comparison with carbon black cumin seeds. The adsorption of Co(II), Ni(II), Cu(II), Cr(VI) and Pb(II) and MB in the solution was investigated by studying the effect of initial concentration, contact time, temperature and pH. The batch adsorption experiments were conducted using different ion solution concentrations of 20, 40, 60, 80 and 100 mg/L, contact time was determined at intervals of 1, 5, 10, 15, 20, 30, 60, 90 and 120 min, while temperature was studied at 298, 303, 313, 333 and 353 K. On the other hand, the effect of pH on all solutions was studied at pH 1, 3,5,7 and 9. The results showed that the acid treated black cumin seeds (AT-BCS) and base treated black cumin seeds (BT-BCS) were successfully used for quaternary adsorption study of Cu(II), Co(II), Pb(II) and Ni(II) ions from aqueous solution. The results for the adsorbents indicated that the BT-BCS adsorbed more metals than AT-BCS and the UT-BCS. The maximum capacity for BT-BCS was 190.7 mg/g for Cu(II) whilst AT-BCS and UT-BCS showed capacities of 180.1 and 135 mg/g respectively for Pb(II). The uptake of Cr(VI) and Cd(II) ions onto pristine black seeds (PBS), KMnO4 black seeds (KMBS) and H3PO4 black seeds (H3BS) treated adsorbents showed that the trend for Cr(VI) ions was KMBS>H3BS>PBS with capacities of 16.12, 15.98 and 10.15 mg/g respectively. Meanwhile the adsorption of Cd(II) ions showed maximum capacities of 19.15, 19.09 and 16.80 mg/g for KMBS, H3BS and PBS respectively. Carbon from black cumin (CBC) seeds was modified with 10 % and 20 % sulfuric acid (H2SO4) then carbonized at 200 °C to obtain the activated adsorbents of ACBC-10 and ACBC-20. The new adsorbents were used for the adsorption of Cd(II) and methylene blue (MB). The adsorbents maximum trend for Cd(II) was ACBC-10>ACBC-20>CBC meanwhile the trend for methylene blue (MB) dye was ACBC-20>ACBC-10>CBC. The overall capacities showed that the prepared materials adsorbed more MB dye (16.42 mg/g) than Cd(II) ions (13.65 mg/g). The preparation of carbon from black cumin seeds (BCC) and activation with 10 and 20 % sulfuric acid (H2SO4) at 300 °C to obtain new adsorbents namely (BCAC-10) and (BCAC-20) respectively was used for the adsorption of Pb(II) ions and MB dye from aqueous solution. The maximum adsorption of Pb(II) ions was 17.19, 17.71 and 17.98 mg/g onto BCC, BCAC-10 and BCAC-20 respectively. Whilst for MB dye it was 11.63, 12.71 and 16.85 mg/g onto BCC, BCAC-10 and BCAC-20 respectively. The utilization of pristine Nigella Sativa (PNS) and magnetite-sucrose functionalized Nigella Sativa (FNS) seeds as the adsorbents for the uptake of Cr(VI) and Pb(II) ions from synthetic wastewater revealed that the maximum adsorption capacities for Cr(VI) were 15.6 and 13.0 mg/g onto PNS and FNS composites respectively at pH 1. On the hand, the maximum sorption capacities for Pb(II) ions were 39.7 and 37.9 mg/g onto PNS and FNS respectively at pH 5. The sorption study of Cr(VI), Cd(II) ions and MB dye by pristine Nigella Sativa (PNS) seeds, defatted and carbonized Nigella Sativa seeds from aqueous solution was investigated. The PNS seeds were treated using acetone (then named ANS) and N,N dimethylformamide (named DNS). The defatted ANS and DNS adsorbents were carbonized at 600 °C and named CANS and CDNS. The results of pristine, defatted and carbonized seeds maximum capacities were compared with each other and found that CANS had highest adsorption capacity of 99.82 mg/g for MB, 96.89 mg/g for Cd(II) and 87.44 mg/g for Cr(VI) followed by CDNS with 93.90, 73.91 and 65.38 mg/g for MB, Cd(II) and Cr(VI) respectively. ANS capacities were 58.44, 45.28 and 48.96 mg/g whilst DNS capacities were 48.19, 32.69 and 34.65 mg/g for MB, Cd and Cr(VI) respectively. PNS had the lowest sorption capacities at 43.88, 36.01 and 19.84 mg/g for MB, Cd and Cr(VI) respectively. Therefore, this makes black cumin seeds a promising material for use in wastewater treatment to mitigate metal ions and dye pollution.Item An adsorptive study of Pb(II), Cr(VI) ions and methylene blue dye by treated and untreated coral limestones in aqueous solution(Vaal University of Technology, 2021) Nkutha, Cynthia Sibongile; Naidoo, E. B., Prof.; Shooto, N. D., Dr.For centuries the contamination of surface water has been problematic, especially in third world countries whereby socio-economic issues are prevalent. With the development of various technologies for surface water rehabilitation, adsorption has been found to be the most viable due to its lower cost implications. As such the development of innovative adsorbents which are synergistic to the low cost method have been sought. Herein, the use of fossil coral limestone from Mauritius as adsorbents for the removal of Pb(II), Cr(VI) and methylene blue is presented. The pristine material (PCLS) was thermally treated by calcination to temperatures 800°C (CLS-800) and 900°C (CLS-900) and chemically treated by using an acid HCl (ACL) and base NaOH (BCL). The optimum conditions found for chemical and thermal treatment of the pristine material were used for the one pot synthesis of magnetite and maghemite calcium carbonate based nanocomposites. The pristine fossil coral limestones were characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDS), X-ray fluorescence XRF), X-ray diffractometer (XRD), Brunauer, Emmett and Teller (BET) and Fourier transformed infrared (FTIR) spectroscopy, UV visible spectrophotometer (UV/vis) and Photolumiscent spectroscopy (PL). Surface morphology of the material was found to contain an interconnected framework of pores, with a surface area of 20.45 m2/g and pore with of 4.04 nm. Thermal treatment of the material was found to increase the surface area of the materials to 64.10 and 63.28 m2/g for CLS-800 and CLS-900. The surface morphology of the calcined materials compared to the pristine were fibrous like and irregularly shaped for CLS-800 and CLS-900 respectively. The FTIR revealed the dominant surface groups to be (-C-O) and (-C=O) asymmetric stretch of the in and out of plane bend of carbonate (-CO32-), with the composition of the material being 91.76 % (-CaO) and 3.32% SrO. The thermally treated materials also exhibited vibrations of asymmetric stretch, which are characteristics of the carbonates as with the pristine material. However, EDS of the pristine compared to that of the calcined materials show a decline in the carbon and oxygen content, due to calcination. The XRD analysis confirmed the orthorhombic structure of aragonite, while CLS-800 was rhombohedral calcite with newly developed (-CaO) peaks. CLS-900 showed complete removal of CaCO3 polymorphs with more (-CaO) peaks. The surface morphology of the chemically modified samples show irregularly shaped surface. The XRD analysis confirmed that chemical treatment did convert the materials to a different polymorph. The FTIR of the chemically modified materials compared to the pristine, were found to reveal a removal of the vibrations of the asymmetric stretch associated with carbonates. However, vibrations associated with (-CaO) were observed. The SEM of the nanocomposites was observed to deviate from sphericity with variable size distribution. The materials were both red and blue shifted due to their variable sizes. Their UV/vis revealed absorption bands in the visible region. The adsorption analysis was done by varying parameters such as time, pH, concentration and temperature. The data was such that the highest capacity for the pristine material was found to be 37.24, 39.26 and 69.42 mg/g for MB, Pb(II) and Cr(VI) respectively. The removal of MB and Pb(II) pollutants were due to physical adsorption, as observed from the good fitting to pseudo first order model (PFOM). The removal of Cr(VI) was due chemisorption and the good fit on pseudo second order model (PSOM). The adsorption process was supported on a heterogeneous surface whereby multilayer adsorption could occur. Adsorption was spontaneous and feasible, exothermic for MB and Pb(II) and endothermic for Cr(VI) at all the studied temperatures as observed from thermodynamics. The adsorption of methylene blue was found to be more favourable on adsorption compared to photo-degradation Chemical modification was observed to increase adsorption and the maximum removal capacities for PCLS, ACL and BCL for Cr(VI) ions were 69.42, 65.04, 64.88 mg/g, Pb(II) ions 39.36, 74.11, 78.34 mg/g and methylene blue 37.24, 46.28, 46.39 mg/g, respectively. Uptake of Cr(VI) and methylene blue on ACL and BCL was feasible on a heterogeneous surface whereby multilayer adsorption took place. Monolayer adsorption on a homogenous surface of ACL and BCL was observed for Pb(II) uptake. The uptake of Pb(II) was exothermic on PCLS and ACL while methylene blue only on PCLS. The adsorption of Cr(VI) ions onto PCLS, ACL and BCL and methylene blue dye onto ACL and BCL were endothermic in nature. The adsorption process was spontaneous and feasible at all the studied temperatures. Thermal modification further increased the adsorption uptake of the pollutants. The recorded uptake for Cr(VI) and Pb(II) were 99.12 and 98.42 mg/g onto CLS-800 and CLS-900, respectively. The adsorption process was found to be physisorption, due to the good fit on PFOM. In addition, the adsorption occurred on a heterogeneous surface whereby multilayer adsorption was possible. The removal of Cr(VI) was found to be exothermic for both the materials and Pb(II) was found to be endothermic. The materials were tested for their reusability to up to four cycles, whereby the removal on the fourth cycle were 16.87, 63.60, 73.13 mg/g for Cr(VI), 9.87, 64.19 and 70.95 mg/g for Pb(II) on PCLS, CLS-800 and CLS-900. While the leaching test for PCLS, CLS-800 and CLS-900 for the release of Ca2+ into solution was found to be within the permissible limits of world health organisation (WHO). The as synthesized nanocomposites increase adsorption of the pollutants. Maximum capacities were found to be 345.34, 388.31, 377.92 and 375.35 mg/g for Pb(II) onto magnetite-PCLS, magnetite-CLS, maghemite-PCLS and maghemite-CLS, respectively and 308.01, 335.3, 335.29 and 335.27 mg/g for Cr(VI) onto magnetite-PCLS, magnetite-CLS, maghemite-PCLS and maghemite-CLS, respectively. From the data it was observed that the maghemite samples were much more favourable for the removal of the pollutants. The removal was due to chemical adsorption, as observed from the good fit onto PSOM and intraparticle diffusion (IPD), whereby surface adsorption was the rate limiting step. The adsorption process was heterogeneous and multilayer, while thermodynamic data reveal that adsorption was spontaneous and favourable at the studied temperature.Item Alanine, aspartic acid and lactose-capped CuS, ZnS and FeS nanoparticles: synthesis, characterization and properties(Vaal University of Technology, 2017) Mofokeng, Thapelo Prince; Shumbula, P. M., Dr.; Moloto, M. J., Prof.Water soluble metal sulfide nanoparticles were successfully synthesized using an aqueous, simple and environmentally friendly synthetic method in the presence of ʟ-alanine, ʟ-aspartic acid and lactose, acting as both stabilizers and crystal growth modifiers. The structural and optical properties of the synthesized metal sulfide nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), Ultraviolet-visible (UV-Vis) and photoluminescence spectroscopy. Colloidal method was employed in the synthesis of CuS, ZnS and FeS nanoparticles from metal chlorides as precursors and thioacetamide (TAA) as a sulphur source. The effect of temperature on the growth and solubility of nanoparticles was investigated. The absorption spectra of all samples prepared were blue shifted as compared to their bulk materials indicating small particles size. The morphologies and sizes of the nanoparticles were influenced by the variation of temperature and capping agent. TEM images revealed interesting changes in the morphology of CuS nanoparticles formed from various capping agents. By varying the temperature, ʟ-aspartic acid-capped CuS nanoparticles changed from rod-shaped particles to particles dominated with hexagonal shape. However, the morphologies of both ZnS and FeS nanoparticles were close to spherical shape and were unaffected by either change of temperature or capping agent. Water-solubility of bio-functionalized CuS, ZnS and FeS nanoparticles was investigated. Amongst the three capping agents used, ʟ-alanine (Ala) was found to be the most effective capping agent to render solubility of the nanoparticles. As the temperature was increased, the solubility of the particles also increased. Cytotoxicity and antimicrobial activity of ʟ-alanine-capped CuS and ZnS nanoparticles were investigated. The particles were less toxic at low to moderate concentrations and only induced toxicity at higher concentrations. Particles synthesized at 95 °C were less toxic compared to other nanoparticles (35 and 65 °C) for both two set of experiments, as informed by the CC50 values. Antimicrobial properties were tested using different strains of both positive and negative bacteria and fungi. It was found that Ala-capped CuS nanoparticles were more effective against the bacteria than Ala-capped ZnS nanoparticles.Item Amino acid-capped metal selenide nanoparticles: their synthesis, characterization, optical and magnetic properties(2018-04) Mokubung, Kopano Edward; Moloto, N; Moloto, M. J.Quantum dots (QDs) have already proven features that can be considered to improve their properties for biological applications. Metal selenide nanoparticles possess semiconducting behaviors that can vary with structural and optical properties evolving from their synthesis. An aqueous medium through a simple, non-toxic and environmentally friendly colloidal route for the preparation of water-soluble CdSe, Cu2Se, FeSe semiconductor nanoparticles has been developed. Different capping molecules with multi-functional moieties (-COOH, -NH2 and -OH) namely, L-cysteine, L-glutamic acid and L-phenylalanine, have been employed in the preparation of cadmium selenide, copper selenide and iron selenide semiconductor nanoparticles as capping molecules. The synthesized metal selenide nanoparticles were characterized by Fourier Transform Infrared (FTIR), UV-Vis spectroscopy, Photoluminescence spectroscopy (PL), X-ray Diffraction (XRD), Vibrating Sample Magnetometer (VSM) and Transmission Electron Microscopy (TEM). The FTIR spectroscopy confirmed the binding moiety through the surface of the nanoparticles which is pH dependent. The XRD patterns confirmed a cubic phase of CdSe and Cu2Se while FeSe revealed a hexagonal phase for the synthesized nanoparticles. The optical absorption as a function of wavelength for the prepared nanoparticles at different temperature is investigated. The morphology of the nanoparticles dominated through this method was spherical in shape. Amino acids capped metal selenide nanoparticles were successfully synthesized by aqueous medium through a simple colloidal route. The absorption spectra of all samples prepared were blue shifted as compared to their bulk counterparts which signify quantum confinement effect. The optical absorption measurements show some dependency of the temperature values used in the synthesis of nanoparticles. The effect of temperature and pH on the growth and morphology of nanoparticles was investigated. X-ray diffraction patterns confirms the structure, single cubic and hexagonal phase for the synthesized nanoparticles. TEM studies of metal selenide nanoparticle show that particle size increases with the increase in reaction temperature. The vibrating sample magnetometer (VSM) shows almost linear without any hysteresis loop for copper selenide, which indicated the absence of magnetism and exhibits paramagnetic nature than diamagnetic properties while iron selenide revealed twofold ferromagnetic behavior in low fields and paramagnetic behavior in up fields.Item Analysis and application of semantic web mechanism for storing and querying ontologies(Vaal University of Technology, 2017-02) Kwuimi, Raoul; Fonou-Dombeu, J. V., Dr.Since the introduction of Semantic Web in the early 2000, storing and querying ontologies have been a subject of greater research. Thus, several types of storage media and mechanisms have been developed to increase storage and query speed and efficiency of ontologies in Semantic Web applications. Existing Semantic Web mechanisms for storing and querying ontologies are implemented on several storage media and support different languages. However, there is a shortage of studies that provide an empirical analysis and application of these ontology storage and query mechanisms in the Semantic Web domain. This study conducted an analysis and application of the Semantic Web mechanisms for storing and querying ontologies. A thorough literature review was carried out to identify relevant publications pertaining to existing Semantic Web mechanisms for storing and querying ontologies as well as the platforms and storage media for implementing these mechanisms. Thereafter, the Design research method was used consisting of a set of predefined steps, namely, awareness, suggestion, development, evaluation, and conclusion. The awareness stage identified the need for an architecture to test several ontology storage media and mechanisms. In the suggestion stage a framework was proposed to empirically analyse and evaluate existing ontology storage and query mechanisms. The required Semantic Web platforms were identified to implement the framework in the development stage. The evaluation stage used a set of metrics to evaluate the framework including: the loading times of ontologies, the disc space used to store the ontology repositories and the mean and variance of query response times. Further, the evaluation stage analysed and discussed the storage mechanisms implemented in Semantic Web platforms. Finally, the outcome of the performance of the framework is presented in the conclusion stage. The framework was practically tested with six ontologies of different formats and sizes on two popular Semantic Web platforms, namely, Sesame and Jena API and the ontology storage and query mechanisms were analysed and compared. Although the underlying structures of repositories in the in-memory and native files in Jena and Sesame could not be accessed, it was possible to access and analyse the data in the repositories in the relational database storage in both Sesame and Jena. The results showed that Sesame relational uses a combination of mechanisms such as normalized triples store in combination with vertical partitioning. That combination allows Sesame to store ontologies based on their contents; in other words, each ontology has a different database schema in Sesame. Jena on the other hand, uses only a normalized triple store mechanism, also known as generic schema mechanism to store ontologies; thus, all ontologies in Jena have the same database schema. The study would be useful to the Semantic Web and Computer Science communities as it does not only provide theoretical knowledge but also the empirical findings that may serve as a base for further development of ontology storage media and mechanisms.Item Antimicrobial activity and dye photodegradation of titanium dioxide nanoparticles immobilized on polyacrylonitrile-cellulose acetate polymer blended nanofibers.(Vaal University of Technology, 2019) Nkabinde, Sibongile Chrestina; Matabola, K. P., Dr.; Moloto, M. J., Prof.Electrospinning is a method that has gained more attention due to its capability in spinning a wide variety of polymeric fibers and nanoparticles embedded in polymer fibers. Polymer blending has been considered the most appropriate way for creating new materials with fused properties which improve poor chemical, mechanical, thermal and dynamic mechanical properties of each polymer. Hence, in this study, electrospinning technique was used to fabricate polyacrylonitrile (PAN) nanofibers at concentrations of (10, 12 and 14 wt%) and cellulose acetate (CA) nanofibers at concentrations of (14, 16 and 18 wt%). 10wt% of PAN and 16 wt% of CA were blended together and the optimum blend ratio was found to be 80/20 PAN/CA. TiO2 nanoparticles (0.2 and 0.4 wt%) were incorporated into CA nanofibers and (1, 2 and 3 wt%) were incorporated into PAN and PAN/CA blended polymers, respectively. Applied voltages of 20, 22 and 24 kV were varied at a spinning distance of 15cm and the optimum voltage for the fabrication of composite was 22 kV. The sol-gel method was used to synthesise the TiO2 nanoparticles at different calcination temperatures of 400, 500 and 600 ºC. The fabricated composite nanofibers were tested for antibacterial and photocatalytic activities. The synthesised nanomaterials were characterized using SEM, TEM, EDX, UV-Vis, PL, FTIR spectroscopy, XRD and TGA. The absorption and emission spectra illustrated the formation of TiO2 nanoparticles and the increase in absorption band edges. TEM showed the spherical morphology of the nanoparticles with average diameter of 12.2 nm for nanoparticles calcined at 500 ºC. SEM illustrated the diameter and morphology of the nanofibers and composites with the average diameter of 220, 338, 181, 250, 538, 294 nm for PAN, CA, PAN-TiO2, CA-TiO2, PAN/CA and PAN/CA-TiO2, respectively. XRD revealed anatase phase as the dominant crystalline phase of the synthesised nanoparticles. FTIR spectroscopy and EDX signified that the formation of composite nanofibers and the presence of TiO2 nanoparticles corresponded to the Ti-O stretching and Ti-O-Ti bands on the FTIR spectra. The antimicrobial activity of the composite nanofibers were tested against E. coli, S. aureus and C. albicans microorganisms. The photocatalytic activity of the nanomaterials was tested using methyl orange dye. PAN/CA-TiO2 composite nanofibers revealed the greatest antibacterial activity against selected microorganisms as compared to the other nanocomposites. PAN/CA-TiO2 nanocomposite (44%) showed greater rate of photodegradation of methyl orange than PAN-TiO2 nanofibers (28%) and TiO2 nanoparticles (12%) under visible light irradiation.Item Antimicrobial activity of synthesized copper chalcogenides nanoparticles and plant extracts.(2019-03) Mbewana, Nokhanyo; Mubiayi, Kalenga Pierre, Dr; Mthunzi, Fanyana, Dr; Moloto, Makwena Justice, ProfChemical precipitation method is the most widely used of all methods for preparing good quality semiconductor nanoparticles. Several conditions are optimized for producing the desired size and shape of particles. The parameters such as capping molecule, precursor concentration, time and temperature were investigated using the colloidal hot injection method. The effect of capping agent was the first parameter investigated in the synthesis of copper selenide, copper sulphide and copper oxide nanoparticles. The capping agents of interest in this study were oleylamine (OLA) and trioctylphosphine (TOP), due to their ability to act as reducing agents, surfactant, solvent and enhancement of colloidal stabilization. The use of oleylamine and trioctylphosphine were carried out at 220 °C for 30 minutes. The optical and structural properties of the yielded nanoparticles were characterize using UV/Vis spectroscopy, TEM and XRD and showed dependence on the type capping interactions from the two agents. Nanoparticles synthesized using TOP produced two phases whereas a single phase was observed from OLA as confirmed by XRD. OLA produced bigger particle sizes compared to TOP but with a wider variety of shapes. The wide variety of particle structures of OLA capped nanoparticles was advantageous since different types of bacteria were targeted in this work. Therefore, other synthetic parameters were investigated using OLA as both solvent and capping molecule. Precursor concentration ratio showed bigger effect in the size, and shape of the yielded nanoparticles. For copper selenide and copper sulphide (Cu: Se/ S), 1:1 concentration ratio gave the best optical and structural properties while copper oxide (CuO) nanoparticles demonstrated its best optical and structural properties in 2:1 ratio (Cu: O). Nonetheless, 1:1 precursor concentration ratio was used to optimise other parameters. Since reaction time has a profound effect on the nanocrystals size and shapes, the effect of reaction time in OLA was also investigated. The reaction time showed no effect on the phase composition of the synthesized copper sulphide, copper oxide and copper selenide nanoparticles. Reaction time of 30 minutes gave the best optical (the shape of the absorption band edge and emission maxima values) and structural (size distribution of particles) properties for CuSe and CuS compared to other reaction times (15 min, 45 and 60 min). 15 min reaction time gave the best optical and structural properties for copper oxide but nonetheless, 30 min was used as the optimum reaction time for further optimization. Temperature showed an effect in size, shape and the stoichiometry of the reaction. These effects were confirmed by the optical and structural properties of the synthesized nanoparticles. XRD patterns revealed some differences with the temperature change, indicating an effect on the phase composition of CuS and CuO but not on CuSe nanoparticles. CuSe and CuS nanoparticles synthesized at 220 °C gave the ideal optical and morphological features compared to other temperatures that were selected (160 ºC, 190 ºC and 240 ºC). Nonetheless, CuO revealed its best optical and structural properties at 160 ºC. 220 ºC was deduced to be the optimum temperature for the synthesis of these three materials under the synthetic conditions. The optimum parameter (220 ºC, 30 min and 1:1 ratio) were used to synthesize the three copper chalcogenides which were then tested against Gram-negative (E. coli and P. aeruginosa), Gram-positive (S. aureus and E. faecalis), and fungi (C. albicans). The plant species, Combretum molle and Acacia mearnsii were phytochemical screened for the presence of active organic compounds and the content of total phenols, flavonoids and antioxidants using different solvents. Both C. molle and A. mearnsii revealed the highest phenolic content in acetone extracts. C. molle revealed its highest flavonoid content in methanol extract and its highest free radical scavenging activity in acetone extract. Acetone extracts demonstrated the highest flavonoid content as well as the highest free radical scavenging activity of A. meansii. The solubility of copper chalcogenides and plant extract was tested in four different solvents and the solvent that demonstrated highest solubility was used for the coordination of the plant extract and copper chalcogenides. The plant extract coordinated nanoparticles were tested for their antibacterial and antifungal activity. Their results were compared to those of the active ingredient in their respective solvents from the medicinal plants as well as those of copper chalcogenides nanoparticles without plant extracts using diffusion disk and MICs methods. The synthesized nanoparticles showed better performance than plant extracts with copper oxide performing the best, followed by copper selenide and lastly by copper sulfide. The performance of plants extracts highly dependent on the solvent of extract with acetone showing the best performance for both C. molle and A. Mearnsii followed by ethanol. The addition of active ingredients from C. molle and A. mearnsii to the synthesized nanoparticles did not enhance the performance of these nanoparticles.Item Antimycobacterial activity of synthetic compounds isolated from South African medicinal plants against mycobacterium tuberculosis(Vaal University of Technology, 2014-11) Ledwaba, Elizabeth Ramadimetsa; Bapela, N. B., Dr.; Van Wyk, ChristaTuberculosis (TB) remains one of the most difficult infectious diseases to control in the world today. The disease spreads easily in overcrowded, badly ventilated places and among people who are undernourished. Trends in the incidence of TB together with the development of multi-drug (MDR-TB) and extensively drug resistant (XDR-TB) strains of TB raises the need to intensify the search for more efficient drugs to combat this disease. Herbal remedies used in traditional medicine provide an interesting and largely unexplored source for the discovery of potentially new drugs for infections such as TB. The aim of the study was to evaluate the in vitro antimycobacterial activity of synthesized compounds from medicinal plants against Mycobacterium tuberculosis (M. tuberculosis). About 40 synthesized compounds isolated from South African medicinal plants were screened against H37RV using microplate alamar blue assay (MABA). Identified active compounds were screened against resistant strains of M. tuberculosis (MDR, XDR and pre-XDR) and sensitive clinical isolates of TB. Cytotoxicity and synergistic drug combination studies were done on active compounds to validate their toxicity and synergy levels. Cytotoxicity was done by sulforhodamine assay (SRB) against the C2C12 cell line. Only six compounds showed activity against M. tuberculosis with minimum inhibitory concentration (MIC) below 10μg/ml. The results obtained indicated that the cytotoxicity effects of the three compounds on C2C12 cells demonstrated marginal toxicity except for MVB 282/61215 which showed a high toxicity at the lowest concentration of 0.156μg/ml with over 100% viable cells at the highest concentration (5μg/ml). MVB 282/61271 had the highest percentage cell viability (65%) at the lowest concentration. Only two compounds had a higher potency evoking a bigger response at low concentrations with treated cells still viable after 3 days of incubation with the compound which was comparable with the treatment of isoniazid (INH). Synergistic activity of the six compounds was less in INH combination as compared to the rifampicin’s (RIF) combination. The results demonstrated that the synergistic interaction between the compounds and RIF could the antituberculosis acitivity. In conclusion the synergistic effects with RIF translate to lower dosing requirements of the compounds and the potential to combat multidrug resistant TB. In deed there is no doubt that natural products, with their range of interesting chemical structures and powerful antimycobacterial effects are certain to remain important participants in the development of new generations of antimycobacterial drugs.Item An approach to a creative pedagogy to improve the learner-content relation in Tertiary ICT education in South Africa.(Vaal University of Technology, 2018-12) Van Eck, Rene; Jordaan, A., ProfThe work-integrated learning (WIL) concept was introduced to enhance the employability of students completing their IT qualification at universities of Technology (UoTs) in South Africa. Employability is defined as a combination of characteristics that make a person a useful and thereby desirable employee. WIL is defined as a component of a curriculum to improve the value of student learning by integrating academic training and practical workplace exposure. However, a large cohort of students registered for the IT qualification at UoTs do not find company placement for WIL, resulting in these students having to complete this final qualifying module of their qualification by undertaking a group project on campus. The group project entails developing a software system for a client. The overall sentiment expressed by employers, lecturers and students in this study is that students who remain on campus for the group project are not as well-prepared as those who find placement at a company for their in-service training. This study aimed to develop and propose an approach to a creative pedagogy in the form of a simulated working environment on campus within a tertiary educational setting to contribute towards enhancing the learner-content relation of WIL students, in order to improve the employability of students by providing the on-campus project students with an equal opportunity to those going into industry for their in-service training. The philosophy adopted for this research is interpretivism, with the Vaal University of Technology as the case of the research. The investigation adopted a mixed-method approach where respondents were requested to complete questionnaires focusing on their perceptions of on-campus group work vs. in-service training at companies for the WIL component of the IT qualification. Five respondent groups were identified for participation in the study, namely: i) In-service training students, i.e. WIL students who found placement in a company; ii) Project students, i.e. WIL students who remained on campus to do a group project; iii) Graduates, i.e. students who already completed WIL and graduated; iv) Employers of WIL students who found placement at a company; and v) Lecturers involved in WIL training on campus. The responses of the various respondent groups were analysed qualitatively and quantitatively. Comparisons of the perceptions of the respective groups were made to explore the possibility of a viable solution to the on-campus group work challenges that were identified. Based on reviewing recent literature, analysing the data collected from the completed to questionnaires by different role players, and adapting and the institutional strategy framework for WIL developed by Jacobs in 2015, an approach to a creative pedagogy in the form of a virtual company on campus for WIL students is presented to provide students who cannot find placement in industry for their in-service training with an equal experience to the in-service training company students. The proposed pedagogical approach incorporates the five standards defined by Tharp in 2018 as requirements for an effective and successful curriculum in the development of the actual virtual company. These include: contextualisation, challenging activities, joint productive activity, intellectual conversation and language development. The proposed approach adopts a three-layered approach to a creative pedagogy, with the aim of improving the employability of on-campus WIL students. The first layer lays the basis for implementing a virtual company on campus and includes aspects such as the objective for a simulated working environment on campus, employer preferences, and the skills set students should possess for employers to offer them a placement in their company for in-service training. The second layer focuses on the details that should be in place for a virtual company to be successfully implemented. This practical layer in the implementation of the virtual company focuses on infrastructure, Finance, HR, legislative approval, and appropriate assessments. The third layer only follows when the second layer has been put into place. This layer deals with how academic content can be included in the proposed pedagogical approach. The study also revealed that in addition to adopting the concept of a virtual company on campus for WIL students, a substantial focus should be on soft skills training. The exit level outcomes (ELOs) related to a simulated working environment for the WIL module of the IT are specified in the HEQF (Higher Education Qualifications Framework) document as set out by the South African Qualifications Authority.Item Assessing the genetic diversity of Alternaria Bataticola in South Africa using molecular markers(2015) Chalwe, Joseph Musonda; Pillay, Michael; Adebola, PatrickSweetpotato (Ipomoea batatas) is an important food crop that is grown in many countries. A number of viral and fungal sweetpotato diseases have been reported worldwide. One of the major and most economic diseases of the sweetpotato is Alternaria blight which is caused by the fungal pathogen Alternaria bataticola. This disease can be managed in a short term using fungicides and cultural practices. However, a long term and inexpensive approach is through the development of resistant cultivars. A prerequisite to this approach is the knowledge of the genetic diversity of this fungal pathogen. This study assessed the genetic diversity of 25 South African isolates of A. bataticola from naturally infected leaves and stems collected from different sweetpotato growing regions in South Africa by (i) characterising the isolates based on their morphology (ii) pathogenicity tests (iii) random amplified polymorphic DNA (RAPD) (iv) variation of the ITS2 sequences and (v) prediction of the ITS2 secondary structures. The isolates revealed some variation in colony colour pigments after culturing but Koch’s postulates were confirmed by their pathogenicity tests. The analysis of RAPD and variation of the ITS2 sequences showed high levels of variation (100%) among the isolates. Dendrograms generated from these analyses had many subclusters and did not cluster the isolates according to their geographic origins. The ITS2 secondary structures were predicted and can be used to identify and distinguish the isolates. This information in addition to the genetic diversity of the A. bataticola isolates will aid plant breeders in the development of resistant sweetpotato cultivars and early management of blight disease in South Africa.Item Assessing the genetic diversity of South African sweetpotato germplasm using DNA and protein markers(2013-06) Selaocoe, Maleshoane EllenSweetpotato is one of the most important food crops in developing countries including South Africa. Currently two major types of cultivars are grown in South Africa: one is the orange-fleshed sweetpotato (OFSP) which has high β-carotene content, a precursor of vitamin A. The second type is the cream-fleshed sweetpotato (CFSP) which has low β-carotene content but is high in dry matter. Most South Africans prefer the CFSP although the OFSP offers more advantages. This presents a challenge to plant breeders to develop new varieties that will combine the desirable qualities of both the cultivars. To achieve this goal, plant breeders need knowledge about the genetic variation of the crop to develop an efficient breeding programme. This study assessed the genetic relationships of 28 orange- and cream-fleshed sweetpotato accessions by (i) examining the variation in leaf proteins, (ii) using random amplified polymorphic DNA (RAPD) and, (iii) using variation of the ITS region. The analysis of proteins, RAPD and variation of the ITS region polymorphism levels were 55.6%, 98% and 16.5%, respectively. Dendrograms generated from all the analyses generally clustered the accession according to their flesh colour and country of origin. Analysis of molecular variance (AMOVA) found a significant difference between OFSP and CFSP and a significant difference between the South African and non-South African germplasm. The high genetic diversity in the South African sweetpotato germplasm is a positive indicator for a breeding programme that has a number of targets such as breeding for nutritional improvement, disease resistance and drought toleranceItem Assessing the morphological variation and characterising the proteins of bambara groundnut (Vigna Subterranea L. Verdc)(Vaal University of Technology, 2016-12) Evangeline, Unigwe Amara; Adebola, Dr. P.; Pillay, Prof. M.Bambara groundnut (Vigna subterranea L. Verdc) is an underutilized crop in the African continent. It is a drought tolerant crop and fixes atmospheric nitrogen. Bambara groundnut is primarily grown for the protein content of its seeds and is mainly produced by small scale farmers at the subsistence level. However, despite its importance as a subsistence crop in many African countries, only local landraces of bambara groundnut are still cultivated. Mass selection of a few local varieties for the main agronomic characteristics has been carried out. All the bambara groundnut germplasm in South Africa has not been morphologically characterized. Although the protein of bambara groundnut is of good quality and is rich in lysine, there is no information on the characterisation of these proteins. The presence of antinutritional factors in the crop has also received little attention. This study focused on three major objectives including: (I) to assess the extent of morphological variations among thirty selected landraces of bambara groundnut, (II) to characterize the major seed proteins in these accessions using one dimensional gel electrophoresis, and (III) to determine the presence of any anti-nutritional factors in the seeds of the selected bambara groundnut landraces. 30 accessions of bambara groundnut were evaluated for their variability in agronomic and morphological traits. The field experiment was conducted at ARC-VOPI in Roodeplaat research farm during the 2014/2015 summer cropping season. The field trial was arranged as a complete randomized block design with 3 replications. 18 quantitative traits were recorded to estimate the level of genetic variability among accessions. 4 different methods were employed to extract seed proteins from 30 bambara groundnut accessions in order to ascertain the best method for protein extraction. These methods included: 10%-80% isopropanol, 10% trichloroacetic acid (TCA) in acetone solution, sonication and 2x Lammeli buffer extraction methods. The quick start Qubit® fluorometer protein kit was used to determine the protein concentration in each sample. The samples were then subjected to one dimensional gel electrophoresis. For antinutritional analysis, 5 factors (condensed tannins, free and phytic acid phosphate, polyphenol and trypsin contents) were used to determine the amount of antinutrient in 30 bambara seeds that were ground to a fine powdery flour. 3 replicates of all the samples were ground for each assay evaluated. The flour was then immediately extracted and used for the different assays. The analysis of variance revealed significant differences only in 10 of the 18 phenotypic traits that were evaluated. The UPGMA cluster analysis based on the quantitative traits produced four distinct groups of genotypes and a singleton. Genotypes SB11-1A, SB19-1A, SB12-3B and Bambara-12 were found to possess good vegetative characters and are recommended for use as suitable parents when breeding cultivars for fodder production. Desirable yield and yield-related traits were identified in B7-1, SB4-4C, SB19-1A, Bambara-12 and SB16-5A and are recommended as suitable parental lines for bambara groundnut grain production improvement. The quantitative characters therefore provided a useful measure of genetic variability among bambara genotypes and will enable the identification of potential parental materials for future breeding programmes in South Africa. Out of the 4 different seed protein extraction methods exploited for this study, the 2x Laemmli buffer extraction method produced the best result with clear protein bands. A unique feature from all extraction methods was the presence of a common protein band at ̴ 75 kDa. All extraction methods except 10 % TCA-Acetone resolved common banding patterns in all the bambara groundnut samples. This data suggests that there is very little or no intraspecific genetic diversity among the seed proteins of bambara groundnut accessions studied. There was wide variation in the content of the five antinutritional compounds among the thirty bambara groundnut accessions. The mean values for condensed tannin content ranged between 0.20 - 6.20 mg/g. Free phosphate recorded an overall mean of 1.71 mg/g while a range of 1.35 - 4.93 mg/g was observed by phytic acid phosphate (PAP). The polyphenol content had an overall mean of 0.39 mg/g and trypsin inhibitor (TIA) was quite variable among the bambara groundnut accessions ranging from 5.30 - 73.40 TIA/mg. Generally, higher levels of antinutrients were observed in this study compared to the other studies. The results obtained in this study led to a conclusion that although variations exits among the accessions studied, further research is required to verify the extent of morphological variations, the efficiency of protein extractions methods evaluated and the effects of these antinutrients in human and animal feeds.Item Assessing the pollutant removal efficiency of a wetland as a polishing treatment for municipal wastewater(Vaal University of Technology, 2021-02-16) Mphuthi, Betty Refilwe; Osifo, P., Prof.; Walmsley, T. A., Dr.Pollution of aquatic systems by wastewater containing pathogens, heavy metals and high concentrations of nutrients is of great concern due the ecological risks they impose. The toxic effects of metals may occur even at low concentrations because of potential bio magnification in the food chain. Excessive nutrients cause algal blooms which depletes oxygen and prevents sunlight from penetrating into the water, thereby killing fish and other aquatic organisms. This study investigated the pollutant removal efficiency of a riparian wetland located in Sebokeng, Emfuleni local municipality, South Africa. The study was carried out to assess the water quality of a wetland located downstream of the Sebokeng wastewater treatment plant by monitoring and analysing the physico-chemical parameters which included pH, temperature, electrical conductivity, nutrient levels (nitrates, phosphates, nitrites) and heavy metals. The water samples were collected from the effluent discharge of the treatment plant, upstream and downstream of the wetland. Plant uptake of heavy metals in a riparian wetland, nitrification as well as denitrification processes have been historically recorded as the main processes that contribute to the high removal of pollutants in a wetland. The contaminant concentrations of the influent and the effluent were used to estimate the wetland efficiency in improving the water quality that passes through it and its potential effects on improving the quality of irrigation waters. The heavy metals of interest included Al, Cd, Cr, Cu, Fe, Pb, Mn and Zn. Most heavy metals within the wetland occurred at low concentrations (lower than detectable limits and within the discharge limits for irrigation purposes). The results indicate that the average removal efficiencies for Electrical Conductivity (EC), Total coliforms (TC), E. coli, BOD5, COD, TSS, carbonate hardness, aluminium, iron, manganese, copper, nitrite, nitrate, sulfate and ortho-phosphate were 43 %, 51%, 85%, 60%, 61%, 61%, 21%, 67%, 52%, 51%, 83%, 56%, 89%, 49% and 54% respectively. The study showed that this wetland can provide up to 89% removal efficiency of pollutants. Of particular significance was the high pathogen and nutrient removal efficiency. A t-test was performed in order to determine the statistical significance of the wetland pollutant removal efficiencies. All p-values calculated were well below 0.05 and the removal efficiencies are therefore considered statistically significant. For this particular ecosystem the findings show that there is no great concern about metal pollution since most of the metals tested for were below the minimum limit for irrigation stipulated by the South African water regulation department (DWAF 1996a). Therefore, the wetland effluent water qualifies for both agriculture and landscape irrigation. Future considerations in choosing to use wetlands as a polishing facility for wastewater treatment systems are highlighted in the study.Item Assessment of e-learning readiness in South African schools.(Vaal University of Technology, 2019) Kolo, Ditlalane Irene; Van Eck, René; Zuva, Tranos, Prof.The delivery of education and/or curriculum is shifting from the traditional method of delivery to a digital format, most notably the e-learning, using available technology. However, without e-learning readiness, e-learning benefits will not be reaped and the probability of failure in adopting e-learning will be high. Therefore, it is imperative to know the levels of readiness for e-learning of educators and learners in South African schools. In this study, e-learning readiness of the South African educators and learners in previously disadvantaged schools in Gauteng were investigated. A twenty-nine (29) item questionnaire was used to obtain the data. This new learning method is being introduced and will be implemented by Gauteng Department of Education. The data obtained from the questionnaires was then analyzed by using a STOPE (Strategy, Technology, Organization, People and Environment) model. The results obtained by using STOPE analysis indicated the overall readiness for e-learning at a level of 77%. This is above the mid-point of 50% showing that the schools in Gauteng are ready for adoption of e-learning. The five-point Likert scale method was also used to check the e-learning readiness and established a level of 3.86. The schools in Gauteng that participated in our study are ready for e-learning adoption but need to improve on their people and content readiness. These schools show that they will benefit in adopting e-learning in their schools.Item Asset tracking, monitoring and recovery system based on hybrid radio frequency identification and global positioning system technologies(Vaal University of Technology, 2021) Matshego, Itumeleng Olebogeng; Appiah, M., Dr.; Zuva, Tranos, Prof.Tracking involves information gathering, manipulation and proving information on the location of a set item. Many single or hybrid technologies – Global Positioning System (GPS), Radio Frequency (RF), Bluetooth (BLT) or Wireless Fidelity (WiFi) – have been used to provide tracking information of an asset of interest. The use of hybrid technology in tracking assets has proven to be effective if the selection of the technologies used is done correctly. This study used a hybrid of GPS and Radio Frequency technologies to track assets of interest because of their characteristics for use inside and outside a building. In this study GPS geo-fencing was used and time interval was used to receive data from the technology. Heuristic methodology, which enabled us to divide a room into sections, was used, where testing was done in sections in a room with different types of material, such as bricks, wood or metal, and the RF signal degradation, called attenuation, was measured. A straight-line distance and a sum of distances at 30-minute intervals were calculated to determine how far the asset had travelled from the point of origin to the new position. A distance of less than 10 metres was ignored. Geofencing was used to trigger an event since it indicates that the asset has crossed the permitted boundary. An RF reader was placed at the door to identify when the asset left a building and triggered an event. A model was used for searching for a missing item in a room. The results showed that the system was able to produce two distances, one straight-line distance and the other the approximate sum distance travelled by the asset in 30-minute intervals. The RF model was able to find an asset in a room filled with different materials.