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Tactile memory: a haptic architectural approach is explored as a way of revitalizing the historic lime works in Olifantsfontein through the process of making ceramic works as an exhibitionist element
No full textThis dissertation explores the reactions that architectural experience can elicit, specifically by means of sensory stimulation. William J Mitchell associates sensory stimulation with the recollection of memories (2005:8), which causes an enhanced experience through a layering of different times/moments (the current moment and the remembered time).
Time is an important factor in the exploration, and as such the research is focused on sites with layered historical narratives within the South African context. The art history and development of Olifantsfontein in Gauteng recently came to light with the publication of Olifantsfontein Potteries 1907-1962. The potteries were originally started by Cullinan as part of the Consolidated Rand Brick, Pottery and Lime Company (Conrand). Between 1895 and the late 1950’s Conrand was the driving force behind the development of Olifantsfontein. The original site of Conrand has since been subdivided and developed, but the portion that housed the lime works remains undeveloped. Some reminders of the lime works remain on the site, albeit in a state of ruination. These include a lime quarry, a historic lime kiln and a cemetery.
The proposed intervention aims to celebrate the history of Olifantsfontein through the development of ceramics studios and galleries on the aforementioned site. The proposed program alludes to the concept of haptic architecture as a stimulus for recollection.
The enhancement of architectural experience is further explored by developing the process of ceramic making as an exhibitionist element to showcase the tactile quality of the program. For this purpose the aspects of ceramic making is examined and discussed
Outcomes of patients receiving radical radiation with concurrent chemotherapy for vulva cancer at Universitas Hospital Oncology Department, Free State, South Africa
No full textIntroduction and aim: Although cancer of the vulva is relatively rare in the developed world, incidence is increasing worldwide. In South Africa, increased incidence is accompanied by a decrease in age at diagnosis. Whereas patients in developed countries are often operable at presentation and undergo surgery, limited resources and the extent of presenting disease in our setting lead to an approach aiming for cure with primary radiotherapy and concurrent chemotherapy in many instances. Even with curable disease, the morbidity and mortality in these patients are high. This study aimed to measure survival outcomes in this group of patients.
Methods: This is a retrospective, descriptive cohort study of vulva carcinoma patients receiving radical treatment from 2006 to 2010. We collected demographic, treatment and follow-up data, and date of death where available.
Results: A total of 55 patients presented in the trial period, of which 30 met the inclusion criteria. The study population had a mean age 50 years, and 52% were HIV positive, of which 17% were on HAART. Of the HIV positive participants, most had a CD4 count above 400. Most patients had stage 3, moderately differentiated disease. The mean radiation dose received was 66.3 Gy, and nearly all patients completed concurrent chemotherapy. Adequate follow up data was only available for 7 participants, and date of death was only available for four. Survival parameters could thus not be calculated for this cohort.
Conclusion: Compared to departmental numbers from 2016 and 2017, the size of our cohort was small, which gives the impression that the incidence of vulva carcinoma is increasing. We concluded that our population is not comparable to international populations, which prompts interest in finding individualized treatment. However, more studies are needed to investigate survival of these patients receiving definitive radiotherapy with concurrent chemotherapy
Relationship between sorghum plant and grain characteristics, colonisation by mycotoxigenic Fusarium spp. and mycotoxin levels
No full textSorghum grain mold is an economically destructive disease that can influence both the yield and quality of the grain. Causal fungi include Fusarium spp. that produce mycotoxins that affect the wellbeing of humans and animals. Ways to improve disease resistance have been explored and include exploitation of physical and chemical traits, and cultivation practices.
Field trials were conducted at Cedara and Alma to evaluate sorghum grain mold resistance in 22 sorghum lines representing the range of plant and grain characteristics in commercially planted cultivars. Grain mold visual ratings, fungal biomass through ergosterol analysis, FGSC (F. graminearum species complex) quantification by means of qPCR and subsequent mycotoxin concentrations were analysed. Only purple plant colour was associated with higher grain mold ratings. No other grain characteristic were associated with resistance to colonisation or mycotoxins produced, which led to the assumption that resistance appears to be the result of complex reactions. The wetter Cedara had higher grain visual ratings, FGSC colonisation and subsequent mycotoxin production. AMMI analysis revealed genetic stability to grain mold through changing environments when visual assessments were applied, while ergosterol levels indicated genotypic adaptions to different environments. A multi-variable approach is needed for evaluation of resistance.
Grain of the 22 sorghum lines planted in Cedara and Alma were evaluated for chemical traits contributing to grain mold resistance. The highest total phenolic acid levels were recorded in red pericarp grain compared to the lowest found in white pericarp grain. Total phenolic acids for half of the lines remained stable levels across environmental changes as indicated through AMMI analysis. HPLC analysis indicated inconsistent levels of specific phenolic compounds across genotypes, with the exception of gallic acid that correlated with resistance to grain mold in genotypes. Higher total protein levels were associated with coloured pericarp grain on a tan plant colour, but no relationship with disease severity was recorded. Similarly no relationship was observed with glucanase and chitinase levels. Further in-depth studies are needed to understand the complex mechanisms involved in resistance.
Rotation systems were introduced into a field trial in Alma to evaluate the effect on grain mold and root rot severity in a high tannin and white tan genotype. Soil nutrient status, root and grain visual ratings, root mass and yield, ergosterol levels, FGSC and subsequent mycotoxin levels were measured. Throughout the trial, an increase in nutrients, root mass and yield were recorded in legume systems compared to fallow and monoculture sorghum systems. The effect of rotation systems on other parameters were variable. Cultivars also differed in their response with NS 5511, the high tannin cultivar, being more resistant to grain mold compared to PAN 8706W, the white tan cultivar, that was more resistant to root rot. Throughout the trial, beneficial effects of legume systems on root rot were observed, while responses to grain pathogens were variable.
Two fungicides, azoxystrobin/difenoconazole and epoxyconazole/pyraclostrobin were applied to four cultivars at different time periods (6, 8, 10, 6 + 8, 8 + 10 weeks after planting) in Potchefstroom, Greytown and Standerton. Only superficial discolourations on the roots and grain, general fungal colonisation and root growth were affected by fungicide treatments. Both fungicides reduced root rot, with only azoxystrobin/difenoconazole being effective against grain mold. Only root growth was stimulated with fungicide applications. Yield, FGSC colonisation and subsequent mycotoxins were influenced more by environment, i.e. locality and seasons, and choice of cultivars and not as a result of fungicide treatments.National Research Foundation (NRF)Sorghum TrustN.E. Borlaug Institut
Rhenium(I) complexes and cancer: synthesis and characterisation of mono- and bi-metallic complexes
No full textOrganometallic compounds such as Re(I) complexes showed to be toxic to a few cancer cell lines, but lack the property of being selective towards cancer cells for the use as novel chemotherapeutic agents. Toxicity tests are preliminary tests performed on different cell lines such as HeLa, HepG2 or PT45 to determine whether the compounds could be used as potential PDT (photodynamic therapy) agents. PDT is the administration of non-toxic drugs or dyes also known as photosensitizers (PS) to patients.
The main aim of this studies were to synthesize two N,Nʹ-bidentate ligands, 1,10- phenanthroline-5,6-dione (phenO2) and 1,10-phenanthroline-5,5-diamine (phen(NH2)2) and this was done successfully with a yield of 52 % and 48 % respectively, as reported in Chapter 3. Re(I) tri- and dicarbonyl complexes with different monodentate ligands: PPh3, PTA and DAPTA were synthesized for the evaluation of their luminescent properties and are reported in Chapter 5. PhenO2 and phen(NH2)2 are used as bridging ligands for the formation of two dinuclear complexes, [NEt4][Re2(CO)6(phen(NH)2)Br2] and [Re2(CO)6(phenO2)Br2]. The N,Nʹ-bidentate ligand, 1,10-phenanthroline, were coordinated to the Ru(III) metal centre which formed the precursor that was used for the synthesis of new bimetallic complexes with a combination of Pt(II) and Re(I) metals. All the compounds were successfully synthesized and characterised by NMR, IR, UV/Vis and elemental analysis as reported in Chapter 3.
The crystal structures of fac-[Re(CO)3(phen)(H2O)][NO3]∙1.5H2O (3), fac- [Re(CO)3(phen)(Br)] (4) and 5-amino-6-nitro-1,10-phenanthroline (phen(NH2)(NO2)) are collected and reported in Chapter 4. 3 and 4 crystallized in the P1� space group while phen(NH2)(NO2) crystallized in the Pbca space group. The Re-CO bond distances of 3 are within the range of 1.864(15) Å to 1.914(13) Å and 4 within the range of 1.902(9) Å to 1.934(7) Å. The Re-N bond distances for 3 is 2.178(8) Å and 2.180(8) Å and for 4 the Re-N distances is 2.183(6) Å. The bite angle of 3 is 76.5(3) ° and the bite angle of 4 is 75.8(2) °. The N-H bond distances of phen(NH2)(NO2) are 0.89(3) Å and 0.93(4) Å, while the N-O bond distances are greater than the N-H distances with bond distances reported as 1.244(3) Å and 1.241(3) Å. The angles between the O-N-O and H- N-H substituents are 120.0 °.
Luminescent studies was performed on the Re(I) tri- and dicarbonyl complexes for the evaluation of their luminescent properties. The Re(I) tricarbonyl complexes with monodentate phosphine ligands, fac-[Re(CO)3(phen)(PPh3)][NO3], fac-[Re(CO)3(phen)(PTA)][NO3] and fac-[Re(CO)3(phen)(DAPTA)][NO3], showed to absorb electrons from a wavelength of 265 nm to 266 nm. Their molar absorptivity coefficient ranges from 11490 to 31185 M-1 cm-1 while their emission wavelengths is at 610 nm. The Re(I) dicarbonyl complexes with bis-phosphine ligands, cis-trans-[Re(CO)2(phen)(PPh3)2][NO3], cis-trans-[Re(CO)2(phen)(PTA)2][NO3] and cis-trans-[Re(CO)2(phen)(DAPTA)2][NO3] showed luminescent properties at excitation wavelengths of 616 nm, 610 nm and 610 nm respectively. cis-trans- [Re(CO)2(phen)(PTA)2][NO3] has the largest molar absorptivity coefficient (14465 M-1 cm-1) of the three dicarbonyl complexes. cis-[Re(CO)2(phen)(PPh3)(Cl)], cis- [Re(CO)2(phen)(PTA)(Cl)] and cis-[Re(CO)2(phen)(DAPTA)(Cl)], the three dicarbonyl complexes with a monodentate phosphine ligands, have smaller molar absorptivity coefficients than all of the Re(I) compounds. These compounds also have greater emission wavelengths ranging from 620 nm to 630 nm.
Three novel bimetallic complexes, [Ru(phen)2(N,Nʹ-phenO2-O,Oʹ)-Re(CO)3Br][PF6]3, [Ru(phen)2(N,Nʹ-phenO2-O,Oʹ)-PtCl2][PF6]3 and [Re(CO)3(N,Nʹ-phenO2-O,Oʹ)-PtCl2]Br with yields of 25 %, 96 % and 98 % respectively, were synthesized to evaluate their cytotoxicity against HeLa and RPE-1 cell lines. [Re(CO)3(N,Nʹ-phenO2-O,Oʹ)-PtCl2]Br is the only complex that showed cytotoxic effects against the HeLa cell line with an IC50 value of 7.31 ± 0.07 μM
Nucleophile assisted carbon dioxide fixation for a cleaner environment
No full textEnglish: Nature has perfected CO2-fixation in plants through the C3, C4 and CAM (crassulacean acid metabolism) mechanisms. Thus, by applying a biomimetic approach to CO2-fixation the knowledge and approach can be ameliorated. This led to the identification of four “non- nucleophilic” bases, which can be categorized as amidines or guanidines, that have an innate ability to coordinate to CO2. The amidines were 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 1,5- diazabicyclo[4.3.0]non-5-ene (DBN) and the guanidines were 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), 1,1,3,3-tetramethylguanidine (TMG).
Overall, the main pursuit of this study was to elucidate on the relevant aspects pertaining to the assimilation and activation pathways of CO2. This was performed by firstly confirming the coordination ability of the bases to CO2 through preliminary solution studies, which indicated that TBD had the strongest ability followed by DBU, DBN and TMG. Thereafter, two model complexes were identified in literature that contained the bases. The general formulae for the two model complexes that were synthesized and characterized were trans-[Pd(L)2Cl2] and [Rh(L)(COD)Cl] (L = (DBU, DBN, TMG, TBD)), except for the TBD-Rh(I) complex.
Of the complexes synthesized, three yielded single crystals, of which two were novel complexes, that were suitable for single-crystal X-ray diffraction (SC-XRD); namely trans-[Pd(DBN)2Cl2], [Rh(COD)(DBU)Cl] and [Rh(COD)(TMG)Cl]. The novel Pd(II) complex packed centrosymmetrically, while the Rh(I) complexes were evaluated on the influence the bases had on the 1,5-cyclooctadiene (COD) conformation by assessing three dihedral angles within the COD. Of the three angles, the most significant difference is seen in the jaw angle (ψ) – between the two complexes (ψ = 75.3(3)° and 64.7(4)° for the DBU and TMG complexes respectively). This was attributed to increased electron density in the π antibonding orbitals on the metal centre, for the latter complex, which resulted in an increase in steric hindrance from the metal centre towards the back-bones of the COD. Therefore, in theory, substitution reactions of the bases by other strong bases would lead to a faster reaction in the TMG-containing complex as opposed to the DBU- Rh(I) complex. This is due to increased reactivity from the two electron donating pathways (σ and π donation) to the metal centre aiding the π back-donation to the diolefin.
This notion was confirmed through extremely fast substitution kinetic reactions observed in the two Rh(I) complexes by 4-dimethylaminopyridine (DMAP) at different temperatures, because the leaving group (being DBU or TMG) determines the rate of attack based on its electron density contribution to the metal centre. Furthermore, the substitution reaction followed a typical and classical associative mechanism and was supported by the negative ΔS≠ value determined for both complexes. The forward rate constant k1 was ten times slower and ca. 3 % less entropy driven for the DBU-complex than for the TMG-complex, with neither experiencing a strong solvation/reverse pathway.
Thus, similar rates may be achieved with CO2 but the rate being limited by the initial activation of CO2 by the bases. Additionally, the large solvent pathway may add to the reaction by performing the reaction under supercritical CO2.Afrikaans: Die natuur het CO2-fiksering in plante deur middel van die C3, C4 en CAM (“Crassulacean”- suurmetabolisme) meganismes vervolmaak. Dus, deur die toepassing van 'n biomimetiese benadering tot CO2-fiksering kan die fundamentele kennis uitgebrei word. Dit het gelei tot die identifisering van vier "nie-nukleofiele" basisse, wat as amidiene of guanidiene gekategoriseer kan word, wat 'n inherente vermoë het om CO2 te koördineer. Die amidiene was 1,8- diazadisiklo[5.4.0]undek-7-een (DBU) en 1,5-diazadisiklo[4.3.0]non-5-een (DBN) en die guanidiene was 1,5,7-triazadisiklo[4.4.0]dek-5-een (TBD), 1,1,3,3-tetrametielguanidien (TMG).
Die hoofdoel van hierdie studie om relevante aspekte rakende die assimilasie- en aktiveringsbane van CO2 te ondersoek. Dit is bewerkstellig deur eerstens die koördinasievermoë van die basisse aan CO2 te evalueer deur middel van voorlopige oplossingstudies, wat daarop dui dat TBD die sterkste vermoë het, gevolg deur DBU, DBN en TMG. Daarna is twee modelkomplekse in die literatuur geïdentifiseer wat die basisse bevat. Die algemene formules vir die twee modelkomplekse wat gesintetiseer en gekarakteriseer, was trans-[Pd(L)2Cl2] en [Rh(L)(COD)Cl] (L = (DBU, DBN, TMG, TBD)).
Van die komplekse wat gesintetiseer is, het drie enkelkristalle gelewer, waarvan twee nuwe komplekse was en geskik vir enkel-kristal X-straaldiffraksie; naamlik trans-[Pd(DBN)2Cl2], [Rh(COD)(DBU)Cl] en [Rh(COD)(TMG)Cl]. Die nuwe Pd(II) kompleks het sentrosymmetries gepak. Die Rh(I) komplekse is geëvalueer deur middel van die invloed wat die basisse op die konformasie van 1,5-siklooktadieen (COD) gehad het, soos gemanifesteer deur drie hoeke binne die COD. Vanuit hierdie drie hoeke is die belangrikste verskil in die kaakhoek (Eng. Jaw angle)
(ψ) waargeneem - tussen die twee komplekse (ψ = 75.3 (3) ° en 64.7 (4) ° vir die DBU en TMG komplekse onderskeidelik). Dit is toegeskryf aan verhoogde elektrondigtheid in die π- antibindingsorbitale op die metalsentrum, vir laasgenoemde kompleks, wat gelei het tot 'n toename in steriese interaksie met die ruggraat van die COD. Gevolglik in teorie, sal substitusiereaksies van hierdie basisse deur ander sterk nukleofiele lei tot 'n vinniger reaksie in die TMG-bevattende kompleks in teenstelling met die DBU-Rh(I) kompleks. Dit is te wyte aan verhoogde reaktiwiteit van die twee elektrondonerende interaksies (σ en π) aan die metalsentrum wat die π terugdonering aan die diolefin help.
Hierdie is bevestig deur middel van baie vinnige substitusiekinetiese reaksies wat by verskillende temperature in die twee Rh(I) komplekse deur 4-dimetielaminopiridien (DMAP) waargeneem word, omdat die verlatende groep (DBU of TMG) die tempo van aanval bepaal op grond van die elektrondigtheidsbydrae tot die metaal sentrum. Verder het die substitusiereaksie 'n tipiese en klassieke assosiatiewe meganisme gevolg soos afgelei van die negatiewe ΔS≠ waarde wat vir beide komplekse waargeneem is. Die voorwaartse tempokonstante k1 was tien keer stadiger en ongeveer
3% minder entropie gedrewe vir die DBU-kompleks in vergelyking met die TMG-kompleks, en het nie 'n sterk oplosmiddel/ terugwaartse getoon nie.
Dus, soortgelyke tempos kan met CO2 behaal word, maar die relatiewe tempo sal afhang van die aanvanklike aktivering van CO2 deur die basisse. Daarbenewens kan die groot oplosmiddelpad bydrae tot die reaksie, deur dit onder superkritiese CO2 uit te voer.SASOLUniversity of the Free Stat
Description of the life stages of forensically important Coleoptera in the central Free State
No full textThe identification and the development of beetles of forensic importance remain
understudied when compared to the number of studies conducted on development
and identification of the life stages of flies of forensic importance in central Free State.
This hinders our understanding of what beetle species are associated with
decomposing carcasses and how we can use their immature stages and their
development to determine Post Mortem Interval. It is important to make correct
species identification when calculating PMI because development data of one species
cannot be used for the forensic significance of another species, even in closely related
species. In recent successional studies that have been conducted in central Free
State, beetles of forensic importance have been identified to family or genus level.
Carcasses used in this experiment were domestic pig (Sus scrofa domesticus) with a
total of three pigs between the weights range of 32.5-49kg, Cape baboon (Papio
ursinus) with a total of two baboons weighing 18 and 19kg and one sheep (Ovis aries)
weighing 44kg. The carcasses were placed on the Western side of the campus of the
University of the Free State. The carcasses were allowed to decompose and insects
were collected twice a day during the decomposition period.
The aim of this project was to describe morphological characteristics, used to develop
keys with which to differentiate between beetle species (adults and immatures)
associated with decaying carcasses in central Free State.
A total of eighteen beetle species representing eight families of forensic importance
(Silphidae, Staphylinidae, Histeridae, Dermestidae, Cleridae, Trogidae,
Scarabaeidae, and Nitidulidae) were collected from the carcasses. Some beetle
species were reared under laboratory conditions with the intention of obtaining
immatures life stages that were not found in the field. The rearing temperature was set
to 28 ± 2ºC and a photoperiod of 12L:12D was maintained in the insectarium. A 3 to
4cm soil layer was laid down in some breeding containers and moist cotton wool was used to maintain the soil moisture levels. In some breeding containers, only sawdust
and styrofoam were used as pupation refugia.
Of eighteen species collected, only two species completed their development under
laboratory conditions. Some of the beetles that were collected are already described
in literature, and these beetles were redescribed using both external and internal
(internal male genitalia) morphological characteristics. Some of the species were only
identified to genus level and, in future, the morphological characteristics and
micrographs provided in this study will help with identification for both successional
and developmental studies.National Research Foundation (NRF)Free State Department of the PremierUniversity of the Free Stat
A strategy to improve the academic support of first-year students in a university access programme
No full textThe study focused on the development of a strategy to improve the academic support of first-year University Access Programme (UAP) students. These students seem to experience a number of challenges, and the nature of these challenges was determined through the literature review. These challenges include inequities in academic support, such as scarcity of tutoring support, the need for peer support programmes, and insufficiency in IT support and training. In addition, there seems to be a need for a preparatory support programme to deal with issues of segregation, rareness of academic support centres, and insufficient academic advising. These challenges could be the obstacles that hinder UAP student’s academic success, progression, and transition to the student’s preferred HE qualification. The identified experienced challenges paved way for the development of a strategy to improve academic support to this cohort of students. Once the strategy was developed, it was significant to identify components of such strategy, and to identify conditions conducive to the implementation of the strategy as what is successful at one institution, will not necessarily return the same results at another institution. In addition, shortcomings of the implemented strategy were identified and disseminated in this study. Functionalism was discussed as the theoretical framework that informed this study. A description of the functionalism was provided, including its evolution, its historical origin and the background in the context of the objectives of this study. Functionalism allowed for better understanding of the challenges that UAP students experienced and facilitated collaboration among the co-researchers in developing the strategy. Moreover, the argument laid by functionalism was that society consists of social institutions, and for society to function smoothly and survive, all the parts that exist within a social institution need to function interdependently and adapt to the everchanging education environment (Benokraitis, 2016: 14; Ferrante, 2013: 31; & Ferrante, 2016: 28). Participatory action research (PAR) was chosen as the research methodology in this study as one of the purposes of PAR is to improve the quality of people’s organisations and lives. Furthermore, researchers who employ PAR, study issues that relate to social problems, and that constrain and repress the lives of students and educators (Creswell, 2012: 582). Additionally, Marincowitz (2003: 595) indicates that PAR is a research process that focuses on improving quality of service by means of a selfreflective process, exploring and problem solving. Similarly, Ary et al. (2010: 515) articulate that PAR is emancipatory and transformational, and aims to challenge unproductive ways of working. In addition, data was collected through focus group discussions facilitated by the FreeAttitude Interview (FAI) technique (Nkonyane, 2014: 18; & Mahlomaholo, 2009: 228). A number of the reasons why focus group discussions were employed in the study were discussed. One of the reasons was to discover information that one would not otherwise access, that is, it is easier for other people to voice their concerns when they realise that others have similar experiences. Therefore, the participants were more comfortable to speak out and engage in discussions; they also provided evidence to reaching conclusions from post hoc analysis of separate statements from each interview. In addition, Focus group interviews work well with Critical Discourse Analysis (CDA), which was employed in this study. Central to CDA was the understanding that discourse was an integral aspect of power and control, that is, this method was chosen as it allows the researcher and the co-researchers to take control of the discussion, and no one feels forced to say something that they were not comfortable sharing with the group (Babbie & Mouton, 2005: 495; Lazar, 2005: 5). FAI and CDA enabled knowledge creation and informed critical aspects pertaining to the study (Lazar, 2005: 5; & Weninger, 2012: 3)
An exploration of mobile learning in South African accounting classrooms: a case study
No full textDissertation (M.Ed. (Curriculum Studies))--University of the Free State, 2019In this digital age, where mobile learning is being incorporated into teaching and learning, this research tries to explore the perceptions and experiences of teachers and learners on the use of mobile learning in South African high school accounting classrooms. Such a study is significant in order to see how mobile learning can enhance and improve the delivery of accounting so that learners will find the subject more enjoyable, develop their critical thinking abilities and understand the benefits of learning accounting at school level.
The study is a case study of three high schools where the delivery of accounting as a school subject incorporates mobile learning. The main findings from the research provide evidence of the following: teachers and learners still do not realise the benefits of mobile learning; although mobile learning has the power to transform teaching and learning, many still think it is only a substitute for the traditional ways; although these learners are the generation that grew up with technology, one should not assume they know how to use it effectively for academic purposes; what will determine how effective mobile learning will be adopted into an accounting teacher’s teaching methods depends on the teacher’s attitude and willingness to adopt; and the resources and software available to high school accounting are not effectively being used. This contributes to both teachers’ and learners’ acceptance of mobile technology in accounting being low, mobile learning currently hindering the understanding of the subject and both learners and teachers not feeling confident in using mobile learning.
This dissertation recommends that for mobile learning to have an impact on the teaching and learning practices of accounting, extensive and in-depth training for both teachers and learners are needed. More research on the use of mobile learning in high school accounting should be carried out. A great need for a more practical and relevant digitally enhanced curriculum exists. Such a curriculum should incorporate the appropriate software that is currently being used in the accounting workplace
A framework for optimising mathematics teaching environments in Thaba Nchu secondary schools
No full textMy educational perspective is based on my background and training. Being a teacher for more than 13 years had a direct influence on my perspectives and, when my own children started school, my whole perspective changed, as my focus shifted from being the teacher of other children, to being the teacher of my own children. For a number of years, I was part of a school partnership programme, where I mentored mathematics teachers in Thaba Nchu township secondary schools. Mentoring the Thaba Nchu mathematics teachers changed my educational perspective once again. These teachers implemented a unique way of teaching, and face a variety of obstacles and challenges. They struggle with problematic situations that teachers in cities take the absence of for granted. Township schools are contextually different from urban schools in many respects, including its geographical features, practices, learners’ support systems at home, and socio-economic status. Despite the challenges that township secondary school mathematics teachers face, they still go the extra mile. Many of them teach seven days a week, they assist learners with regular informal assessments, and they prepare properly for lessons. With the aforementioned in mind, an in-depth literature review indicated that the focus of research in this field has been mainly on the learners and the learning environment, and how the latter can be improved. Teachers are seldom given the opportunity to reflect on the challenges they encounter, or to make suggestions for overcoming these challenges. There is, furthermore, a desperate need in education for better communication and for establishing relationships between teachers, learners and their parents. Unfortunately, one of the realities is that some parents never visit their children’s schools, are undereducated themselves, with Grade 8 or lower school certificates, or are simply not interested in their children’s academic achievements, or the lack thereof. The primary research question of this study was, “What would constitute a framework for the establishment of improved Thaba Nchu secondary school mathematics teaching environments?” To answer this question, an autoethnographic, qualitative research design was used. Observations, field notes, interviews and questionnaires were used to collect data. In aiming to answer the primary research question, the study focused on four major parts. The first part was to determine what literature reports about the experiences of mathematics teachers and their teaching environments. Considering that it was an autoethnographic study, the next part focused on my own background. I used my perspectives as reference framework to understand the experiences of the teachers who participated in the study. Another part of the study focused on how teachers at Thaba Nchu secondary schools experience their teaching environments. To collect data about these attitudes and perspectives, interviews were used. The interviews were transcribed and coded to identify the challenges and positive aspects of the participants’ teaching environments. The data from the interviews were used to develop individualised questionnaires that focused on the fourth part of the study, namely, giving participants an opportunity to make recommendations for improving their teaching environment. The recommendations were ideas about how to address challenges in the Thaba Nchu secondary schools’ mathematics teaching environments, as well as suggestions for ways to nurture the positive aspects of the teaching environments. The questionnaires were transcribed and coded to develop and present a framework based on participants’ recommendations to optimise the mathematics teaching environments of Thaba Nchu secondary schools and, thereby, answering the primary research question. The framework aims, furthermore, to assist mathematics teachers from other township schools in similar situations and environments, to address the challenges they face, and to nurture the positive aspects they experience in their teaching environments. The framework consists of six main themes, namely, resources, parent/guardianrelated aspects, classroom-related aspects, learner-related aspects, teacher-related aspects and school-related aspects. The framework consists of independent parts, which means that each part can be addressed on its own. If all the themes are addressed, optimised teaching environments could be within reach of Thaba Nchu secondary school mathematics teachers
Recovery of platinum group elements from waste material
No full textThe aim of this study was to recover the platinum group elements (PGE) from recycled or waste material using hydrometallurgical techniques. The waste material that was investigated for the possible isolation of PGE is a spent automotive catalytic converter sample, ERM®-EBS504 which is a certified reference material for Pt, Pd and Rh. Surface analysis on the catalyst sample was performed using the scanning electron microscope coupled with energy dispersive X-ray spectroscopy (SEM-EDS) in order to identify the main components of the sample. However, the identification and quantification of the PGE using this technique was ineffective due to the concentrations of PGE in the catalyst sample which were below the detection limits of the SEM-EDS.
Two types of dissolution processes, namely aqua-regia open-beaker dissolution and sodium peroxide (Na2O2) fusion were employed to try and achieve the total dissolution of the automotive catalytic converter sample for the complete and accurate characterisation of PGE using the inductively coupled plasma optical emission spectroscopy (ICP-OES). Aqua-regia dissolution offered partial digestion of the sample and percentage recoveries of 66.9(4) %, 63.9(8) % and 41(1) % were obtained for Pt, Pd and Rh respectively at 80 °C and after a reaction time of 180 minutes. On the other hand, sodium peroxide was able to oxidise all the metals in the catalyst sample to easily soluble oxidation states which allowed for the further dissolution of the sample in aqua-regia. However, challenges in PGE quantification with the ICP-OES were experienced due to unacceptable and unsatisfactory PGE recoveries which were attributed to spectral interferences caused by the excess Na ions introduced from the Na2O2 flux. The introduction of Sc (361.363 nm) as an internal standard compensated effectively for the spectral interference and excellent PGE recoveries were obtained, namely 100(1) % for Pt, 100(3) % for Pd and 103(2) % for Rh. These results were successfully validated in accordance with the criteria of the Internal Standards Organisation (ISO 17025). This method was found suitable and reliable for the quantification of PGE in the automotive catalyst sample at different separation stages. The complete digestion and characterisation of the automotive catalyst sample enabled separation studies of PGE in various aqueous solutions.
The separation methods were firstly studied on artificial samples which emulated to a degree of the original composition of the dissolved automotive catalyst sample. Both solvent extraction and selective precipitation methods were investigated for the possible separation and purification of PGE. Trioctylphisphine oxide (TOPO) and 2- mercaptopyridide N-oxide sodium salt (NaPT) were employed as extractants while NH4OH and 8-hydroxyquinoline (oxine) were used as precipitants. Oxine was found to be highly selective towards the Pd in the solution precipitation in acidic solutions, resulting in the isolation of this element as a highly stable compound which was characterised using XRD, FT-IR, NMR and CHNS micro-elemental analysis. The selective precipitation of the non-precious elements in the presence of PGE using NH4OH was found time-consuming and inconclusive results were obtained for the PGE.
Solvent extraction of PGE using TOPO was found very suitable for the extraction of PGE from chloride solutions. Various parameters which included HCl concentration, ligand concentration, type of diluent and type of stripping reagent were investigated in order to optimise the extraction and selectivity for PGE. An increase in HCl concentration suppressed the extraction of PGE by TOPO, while the degree of Pt extraction was unaffected by this variation. Maximum extraction of all the PGE was observed at 4 M HCl and at high TOPO concentrations. These results improved remarkably when kerosene and hexane were used as diluents. The presence of the non-precious elements interfered to some extent with the extraction of PGE with TOPO. However, various stripping reagents such as NH4SCN proved to be highly selective in the stripping of Pt from Pd, Rh and the non-precious elements, while 2 M HCl proved to be selective towards Rh. Solvent extraction with NaPT proved to be more selective and effective towards Pd. This allowed for the selective isolation of Pd from the PGE and from the non-precious elements. The Pd-mercaptopyridine complex was isolated and successfully characterised with XRD, FT-IR, NMR and CHNS micro-elemental analysis.
These isolation methods were successfully applied to a dissolved and pre- concentrated catalyst sample, and Pt and Pd were successfully recovered with percentage recoveries of 87(4) % and 99(3) % respectively. However, the recovery of Rh using TOPO was unsuccessful, and this was attributed to the formation of the highly stable [RhCl6]3- in the presence of high chloride concentrations. The high chloride content in the solution were as a result of the formation and isolation of NaCl during the dissolution process which complicated the sample matrix, and thus the extraction process of PGE using TOPO. This method was also evaluated on a highly- concentrated rhodium waste solution which had been accumulated in the department, but proved to be ineffective. The recovery of Rh from this waste solution was achieved by the co-precipitation of the non-precious elements using oxine, resulting in Rh recovery of 80(4) % in the filtrate.National Research Foundation (NRF