Implementation of school-based assessment in high schools, Mpumalanga Province, South Africa : implications for teaching and learning
- Authors: Chipfiko, Jack
- Date: 2019
- Subjects: High schools -- Examinations Educational tests and measurements
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/15892 , vital:40549
- Description: The purpose of any education system is to deliver a quality educational product. Various forms of assessment are used to ensure the suitability of the product and inform decisions. In South Africa, School-Based Assessment(SBA) is one of the tools used to assess the content competences, skills, values and attitudes; to provide learners, parents and teachers with results that are a meaningful indication of what the learners know, understand and can do at the time of assessment (DBE, 2012). Surprisingly, on a yearly basis, Umalusi reports reveal that SBA marks are rejected resulting in the learners being resulted on mostly the year end examination. The purpose of this study was to examine the implementation of SBA with a view to unearth the factors contributing to the perennial rejection of SBA marks, resulting in learners from some schools being unfairly assessed. To explore the research problem, a mixed methods study, employing a concurrent triangulation design, was employed. Total Quality Management theory was the theoretical framework anchoring this study. Sub research questions to interrogate the research problem focused on examining the roles of the teachers, learners and parents in the implementation of SBA; assessing the structures in place to support the implementation of SBA; examining how teachers, learners and parents play complementary roles in the implementation of SBA; and identifying strategies to enhance the implementation of SBA in South African (SA) high schools. Data were collected using Questionnaires, interviews and focus group discussions with purposively selected samples of teachers, learners and SGB chairpersons from high schools in White River Circuit in Mpumalanga Province in South Africa. The use of mixed methods produced quantitative and qualitative data which were independently analysed and merged during interpretation. Findings revealed that: participants and respondents confirmed the various roles of SBA in teaching and learning; structures were in place to support the implementation of SBA in high schools; complementarity of roles were sporadic in the implementation of SBA in high schools; and various strategies were employed to enhance the implementation of SBA in high schools. Implications for teaching and learning focused on realigning the implementation processes in the production of a quality educational product, and maximising its benefits to teachers, learners and parents.
- Full Text:
- Date Issued: 2019
Improving the supply of subsidised housing in South Africa
- Authors: Bekker, Jakobus Petrus
- Date: 2017
- Subjects: Housing -- South Africa Housing subsidies -- South Africa , Low-income housing -- South Africa Public housing -- South Africa Housing development -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/19553 , vital:28893
- Description: Despite South African citizen’s constitutional right to adequate housing, Government’s housing delivery has been described as a complex, multi-stakeholder, multi-phase problem, exacerbated by political interference and corruption. Housing delivery in South Africa is ideologically and politically designed and executed. However, the government subsidised housing sector remains plagued by: huge and increasing backlogs; corruption; quality concerns, and recipient and stakeholder dissatisfaction. This includes the government subsidised housing construction sector, which faces issues such as: established contractors leaving the sector; late and failed completion; substandard quality; rework; cost overruns; late progress payments; and insolvencies. Moreover, government subsidised housing officials, which forms part of this sector, must contend with abandoned projects and appointing new contractors; shoddy workmanship from sub-standard contractors; remedial work, including demolition and rebuilding; and systemic problems such as staff shortages and under qualified staff. The process of Government’s ideological and political designed and execution may therefore not have considered certain practicalities relative to construction principles and practice. It therefore appears that there may be some relationship between the compatibility of Government’s housing ideological and political designed (policy) and execution and general construction principles and practice. It is clear from the related literature that government subsidised housing construction has mostly been investigated as an exercise observing from the outside in, and not from a construction sector perspective. The main purpose of this study is thus to explore housing policy and practice compatibility as a major obstacle to housing delivery in general and assess whether the current housing policy is sufficiently responsive to the requirements of the government subsidised housing sector by specifically describing and exploring the effects of Government’s housing procurement policies relative to the ability of the construction sector to supply government subsidised housing. More specifically, the study describes and explores corruption, quality; contractors and worker competency, and government capacity as specific consequences of housing policy and practice incompatibility, as well as factors contributing to recipient dissatisfaction and the housing backlog. Finally, based on the finding, a proposed framework for improving the supply of subsidised housing in South Africa has been developed. The methodology for this study adopted a post-positivist philosophy, embracing a quantitative approach using questionnaires, which incorporated mainly five-point Likert type scale, but also multiple-choice questions, as instruments for data collection. Three surveys were conducted, starting with a pilot study and followed by a primary study, during which a total of 2 884 potential participants within the construction sector across South Africa were randomly sampled and solicited to participate, of which 284 responded. The respondents consisted of four groups: general contractors (76); government housing officials (34); built environment professionals (137), and built environment suppliers (37). An electronic questionnaire was sent by email to all potential participants and allowed four weeks to complete the survey. Furthermore, a housing recipient survey was conducted among 100 randomly selected recipients of government subsidised housing in the Nelson Mandela Metropolitan area, by means of a structured interview using a paper based questionnaire, over a period of two weeks. The primary outcome measures used for this study were the ranked mean scores for mainly descriptive analysis and the Chi-square test, the 𝑡-test, Cohan’s d test, ANOVA and Scheffé test, using Cronbach's alpha as a measure of internal consistency of scale and validity, for inferential analyses and hypotheses testing. Hypothesis testing was founded upon Government’s worldview that its policies will not influence the operations of the construction sector relative to housing construction, and therefore tested respondents’ perspectives with respect to the impact that government policies have in terms of contractor operations and contractor success, as well as its contribution towards the housing backlog, substandard housing, recipient dissatisfaction and corruption. The following results were obtained by means of the hypothesis testing:Government housing procurement policies are inappropriate for application in the government subsidised housing sector. Respondents therefore disagree with the notion that government policy and practices do not impact contractor operations and contractor success, and thus the supply of houses; The application of government housing procurement policies leads to inadequate quality. Respondents therefore disagree with the notion that government preferential procurement policies do not impact quality; Government’s housing procurement policies inappropriately target emerging contractors. Respondents therefore disagree with the notion that Government’s targeting of emerging contractors does not impact housing supply; Government has inadequate capacity to address subsidised housing construction sector requirements in terms of housing projects. Respondents therefore disagree with the notion that Government has the capacity to address subsidised housing construction sector requirements in the supply of housing, and Government subsidised houses do not meet recipients’ expectations. Respondents therefore disagree with the notion that government subsidised houses do meet recipients’ expectations. It thus became apparent that housing supply is mostly inhibited by Government’s housing procurement policy, contributing to various factors, such as quality capability, contractor capability, systemic and administrative capacity, and resulting in recipient dissatisfaction. Using Pearson’s product moment correlation, a framework model was developed to illustrate the process flow, which revealed definitive statistical and practical relationships between these factors, and indeed reflects complex relationships between factors inhibiting supply and resulting in recipient dissatisfaction. To find an appropriate framework model for the purpose of improving housing supply, various sources were consulted. Based on the research question, together with the aims and objectives for this study, as well as the realisation that the problems associated with housing supply relate to the project management of the construction phase, which requires interventions for improving supply, it was decided that a results framework would be the most appropriate for this purpose. The proposed framework is therefore a graphical depiction of how the research process may be used to identify problems in the government subsidised housing sector, questioning how these may be resolved, setting strategies to improve the situation, evolving hypotheses and testing these hypotheses to establish the critical factors to be considered in the process of resolving the problem in the housing sector, by means of implementation and feedback.
- Full Text:
- Date Issued: 2017
In search of identity: an anthropological study on the experiences of Rastafarians in contemporary Malawi
- Authors: Maganga, Stewart Martin
- Date: 2019
- Subjects: Malawi -- Religious life and customs , Rastafari movement Identity (Philosophical concept)
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/42536 , vital:36666
- Description: Prior to 1994, religious freedoms were largely restricted because the constitution at the time vested its powers in the president who was at the time was Dr. Hastings Kamuzu Banda. Banda, who ruled Malawi for thirty years, sought to present Malawi to the outside world as a Christian nation. This was purposefully done by ignoring the existence of other religious faiths in the country of which Rastafari was one. Although the Rastafari movement was in existence during Banda’s presidency, most Rastas found it difficult to practice their religious beliefs freely. Because of this, it was found that throughout the three decades Banda was in power, the Rastafari movement in Malawi was virtually underground. This further gave the public impression to the public at the time that Rastas were non-existent in the country. It was only after the general elections of 1994 that Malawians became aware of the existence of the Rastafari movement in the country. With that said, there remains a paucity of written information on the Rastafari movement in Malawi, that is before and after the 1994 general election. To be able to establish why the Rastafari movement continues to grow in Malawi, this thesis began by addressing the question of why a certain group of individuals would seek becoming to Rastas in Malawi including its impact on their lives including relationships with both friends and family members. For the many that embraced Rastafari, the intention was to embrace a spiritual identity that was separate to that of their parents. Most raised the concern that the religions that they were previously affiliated did not allow them the freedom to explore their spirituality. This further raises the question regarding the link between established religions and spirituality. In as much as Rastafari has provided the individuals in this study a sense of meaning and identity in their lives, they have had to contend with facing confrontation with friends and family members. This thesis also explored the experiences that come with being a Rasta in Malawi. Amongst the issues that are of concern to the Rasta community is that for the many Rasta children that attend public schools, most are denied their right to attend classes with dreadlocks. Most Rastas had hoped that with the advent of democracy in Malawi, their fundamental rights would be recognised and protected under the constitution. What this thesis has demonstrated that despite the existence of democracy in Malawi, it did ultimately result in a society that would be open to diversity. What this study has demonstrated is that Malawi continues to remain a highly conservative society. This is further illustrated in the way Malawian Rastas have had to contend with being denied employment opportunities including their fundamental right to smoke chamba (marijuana) freely. This thesis set out to argue that the democracy brought about by the elections of 1994 did not necessarily result in the improved conditions of minority religious groups like Rastafarians. This is despite the current constitution allowing for religious freedom. Despite this, the thesis further set out to show that the Rastafari movement does have vital role in the current dispensation. The issues that make the Rastafari movement pertinent in present-day Malawi include issues of corruption and neo-colonialism. This thesis concluded that more must be done to improve the conditions of Rastas in Malawi. Some of recommendations that were raised in this study included reviewing the current policy regarding the length of hair that one wears to school as it relates to one’s religious beliefs. The other recommendation that was raised in this study includes amending the Religious and Moral Education (RME) school curriculum in order that it becomes inclusive of other religious faiths that are existing in the country. In addition, the current legislation regarding the possession of chamba must be amended to accommodate for religious groups such as Rastas who use it for religious purposes.
- Full Text:
- Date Issued: 2019
In vivo toxicological evaluation of peptide conjugated gold nanoparticles for potential application in colorectal cancer diagnosis
- Authors: Adewale, Olusola Bolaji
- Date: 2018
- Subjects: Nanostructured materials -- Toxicology , Colon (Anatomy) -- Cancer Rectum -- Cancer
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/50133 , vital:42050
- Description: Colorectal cancer (CRC) is among the leading cause of cancer-related deaths in South Africa and worldwide. Efforts are being made at finding improved diagnostic tools, as early detection (before metastasis) is a major factor in CRC treatment. Colonoscopy is the most reliable detection method, but is a specialised and expensive procedure, which is invasive, not readily available and not patient-friendly. There is a risk of developing interval cancers, as colonoscopies are performed every 10 years after the age of 40. The development of non-invasive, cost efficient and readily available diagnostic tools to CRC, which can be performed at more regular intervals, using tumour-targeting molecular imaging agents, is of urgent attention. Gold nanoparticles (AuNPs) possess several physicochemical properties, including ease of synthesis, biocompatibility, and the ability to be conjugated by ligands or biomolecules such as polyethylene glycol (PEG) and peptides for improved stability, tissue targeting and selectivity. These factors potentiate the role in biomedical applications, including cancer theranostics. Conjugation of AuNPs with a targeting molecule (e.g. antibody or peptide) is directed against cancer cell receptors. The peptides, p.C, p.L, and p.14, bind to CRC cells in vitro. Conjugation of AuNPs with these peptides should be investigated for CRC diagnosis in vivo, as it is hypothesised to allow examinations at shorter intervals through imaging techniques. This could reduce the risk of interval cancers, but before developing this novel tool, in vivo toxicity evaluations are essential. This study was therefore aimed at investigating the short- and long-term toxicological effects of a single intravenous injection of peptides (p.C, p.L, and p.14) conjugated to AuNPs in a healthy rat model. Citrate-capped AuNPs were synthesised by the citrate-reduction method, and conjugated with each peptide (biotinylated) using a combination of PEG (99% PEG-OH and 1% PEG-biotin) as a stabilising agent and linker, via biotin-streptavidin interaction. Healthy male Wistar rats were intravenously injected with 14 nm citrate-AuNPs, PEG-, p.C-PEG, p.L-PEG, and p.14-PEG-AuNPs (100 μg/kg body weight), and the control rats were injected with phosphate buffered saline. The animals were monitored for behavioural, physiological, biochemical, haematological and histological changes, as well as inflammatory responses. Phase 1 rats were sacrificed 2 weeks post-injection to determine the immediate or acute toxicity of the AuNPs, while phase 2 animals were sacrificed 12 weeks post-injection, to investigate the delayed or persistence toxicity of the AuNPs. Results revealed no significant toxicities with the citrate, PEG-, p.C-PEG and p.14-PEG-AuNPs over 12 weeks post-exposure, as evidenced by biochemical assays such as serum marker enzymes, liver and kidney function markers, and cholestatic indicators; haematological parameters; oxidative stress markers; and histopathological examinations. P.L-PEG-AuNPs, however, caused significant toxicity (p<0.05) to rats, as evidenced by increased relative liver weight, increased malondialdehyde levels, and total white blood cell counts 2 weeks post-exposure when compared to the control group. This was, however, reversed during the 12 weeks post-exposure. Further, there were no evidence of inflammatory responses, using pro-inflammatory markers including phospho interleukin 18 (IL-18) and interferon-γ (IFN-γ), as indicated by immunohistochemical staining of the liver, spleen, kidney and colon of rats 2 weeks post-injection of AuNPs. Citrate, PEG-, p.C-PEG, and p.14-PEG-AuNPs did not induce immediate, acute or persistent toxicity, while p.L-PEG-AuNPs induced a transient acute toxicity. It can be concluded that 14 nm spherical citrate-AuNPs at 100 μg/kg body weight is a good candidate for biomedical applications, and as a suitable carrier for diagnostic and/or therapeutic molecules. Combination of 99% PEG-OH and 1% PEG-biotin is an appropriate option for stabilising AuNPs in biological environment, and conjugating secondary diagnostic or therapeutic biomolecules or agents to citrate-capped AuNPs. Peptide-conjugated AuNPs are suitable for the development into a diagnostic tool for CRC in vivo.
- Full Text:
- Date Issued: 2018
Indigenous forests level of deforestation, forest dependency and factors determining willingness to participate in indigenous forest conservation: evidence from resettled farmers of Shamva, Zimbabwe
- Authors: Chivheya, Renias V
- Date: 2016
- Subjects: Forest conservation -- Zimbabwe Forests and forestry -- Economic aspects -- Zimbabwe Deforestation -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/2370 , vital:27786
- Description: This study first explored the rate of forest deforestation in Shamva resettlement areas. It then identified and estimated the extent to which these resettled farmers depend on forest for their livelihoods. Evaluation of farmer perceptions on management issues and willingness to participate in indigenous forest conservation and the socio-economic and institutional factors which affect their willingness to participate were also done. Finally the study sought to identify incentives for forests conservation. The study was conducted in Shamva district in Mashonaland Central province. And the respondents were stratified into three groups: A1, A2 and Old resettlement models. The three models differ on how they were implemented and supported which might render them to have different deforestation rates, livelihood strategies and forest dependency. A total of 247 respondents were surveyed, consisting of 98 A1 farmers, 50 A2 farmers and 99 Old resettled farmers. The data was collected using GIS and remote sensing, structured questionnaire interviews and direct observation. The data was analysed using descriptive analysis, KAP analytic framework and binary logistic regression analysis. The land cover/changes results revealed that both deforestation and afforestation are taking place in Shamva resettlement. Woodland and bushland were decreasing, croplands were also decreasing. However woodland dense and grasslands were increasing. Deforestation was found to be as a result of the resettled farmers’ livelihood strategies which were found to be diverse and agriculture being dominant in all models. All the farmers depended on the forest but at varying levels of 19 percent for Old and 14 percent forA1 and 0.02 percent for A2 resettle farmers. 84 percent of the interviewed farmers however, indicated that they are willing to conserve forest with A1 farmers being the highest followed by A2 86 percent and lastly Old resettled farmers at 76.8 percent. Results of the binary regression model revealed that the significant factors which explain willingness to participate in indigenous forest conservation are age, marital status, education, gender, institution, culture and belief, employment and household size. The highest preferred incentive was the provision of free seedlings and the lowest was out grower scheme. The study recommends that GIS and remote sensing should be used to monitor deforestation, off farm projects be encouraged, exotic and indigenous trees be promoted and forest conservation education be promoted in resettlement areas.
- Full Text:
- Date Issued: 2016
Indigenous knowledge and climate change : insights from Muzarabani, Zimbabwe
- Authors: Chanza, Nelson
- Date: 2014
- Subjects: Indigenous peoples – Ecology – Zimbabwe -- Centenary District , Climatic changes -- Social aspects – Zimbabwe -- Centenary District , Climatic changes – Zimbabwe -- Centenary District
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:10671 , http://hdl.handle.net/10948/d1020299
- Description: Discourse characterising climate change has largely revolved around aspects within the realm of impact identification, mitigation and adaptation. Apparently, a burgeoning appetite to examine the role of indigenous knowledge (IK) now confronts the fronts of climate science, policy and practice. The surge in attention to localbased knowledge is attributed to growing challenges posed by change and variability in the climate system. This study argues that indigenous-based knowledge is capable of filling knowledge gaps and validating current understanding about climate change particularly at local levels. Essentially, the paucity of knowledge about local climatic events can be circumvented by engaging indigenous ‘scientists’ whose many years of direct contact with the environment have equipped them with the indispensable knowledge, skills and experiences to understand the same. Primarily, the thesis’ objectives were threefold. One, it captured useful indicators of climate change and variability from the understanding of the indigenous people, which can also be used to enhance understanding of climate change impacts.Two, it drew from the knowledge, experiences, skills and practices of the locals in order to inform appropriate community level mitigation and adaptation interventions. And, three, it highlighted the fact that knowledge of the indigenous people can be used to direct research on climate change. The study area (Muzarabani in Zimbabwe) experiences recurrent droughts and floods and its villagers rely predominantly on climate-sensitive livelihoods. As such, it was selected to provide a reliable case on IK practices and experiences of the people witnessing climatic events. The study was framed within an epistemological and methodological configuration of emancipatory pedagogy that looks at the generators of climate knowledge as ‘scientists’ in their own right. A qualitative elicitation interviewing technique involving in-depth discussions with traditional leaders and elderly knowledgeable citizens was conducted. The participants were selected through chain referrals until the level of theoretical saturation. In addition, directed field observations, document analysis and key informant interviews with other respondents selected through theoretical sampling enhanced the robustness of data acquisition methods. Group-based participatory data analysis and reflexive pragmatism also enhanced rigour and quality of research findings intended to balance between the strictures of the scientific audience and the views of the knowledge generators. Three key themes were derived from IK-climate change linkages as: indigenous based indicators of climate change, indigenous-based mitigation and indigenous based adaptation. A range of indigenous-based indicators identified pointed to a progressively drier climate with shorter growing seasons that are also punctuated by mid-season dry spells. A trend towards increased desiccation of water bodies (rivers, ponds and vleis) was further observed. There is also an upsurge in the abundance and pestiferous nature of Macrotermes spp, Quelea quelea and Acanthoplus discoidalis, which are most likely related to climate change. Some of these indicators closely match with those used in mainstream climate science and they also serve to understand climate change impacts at a finer local level of analysis. Indigenous-based mitigation is mainly driven by the notion of sacredness where the locals regard forestry, certain trees and vleis as sacrosanct. Tampering with these is believed to upset the spirits who have powers to influence climate. Opportunities associated with IK deployment in climate mitigation are understood from the viewpoint of enhancing greenhouse gas (GHG) sinks and that of reducing vulnerability to extreme climatic events. Specifically, this can be achieved through enhancing GHG sequestration through forestry and land-use management initiatives; that is, reducing emissions from deforestation and forestry related degradation (REDD+) and Land Use and Land-Use Cover and Forestry (LULUCF). These two are the dominant schemes adopted by the Intergovernmental Panel on Climate Change (IPCC) to govern climate mitigation. Indigenous disaster risk management (DRM) strategies abound in drought, famine, flood and violent storms through various forms such as Zunde raMambo, nhimbe, rain-making ceremonies and community early warning systems (EWS).The locals in Muzarabani are not passive observers of the changing climate system. Increasing environmental risks necessitates them to devise countermeasures for responding to climatic stimuli with the intention of minimising harm and/or enhancing the benefits brought about by the same. Thus, a portfolio of IK-based adaptation strategies best described as an assortment of short-term coping practices and longterm adaptive strategies were identified. These range from exploitation of ecosystem services, agricultural based interventions, riverine farming, traditional phonological knowledge (TPK) to migration. Therefore, it was revealed that community-based adaptation (CBA) can adequately leverage on IK to improve adaptive capacity and build community resilience against climate change. Clearly, the complementary role of indigenous-based knowledge cannot be disputed, given the demonstrated range of applications from identifying several indicators of change and variability in the climate system, examination of climate change impacts, to identification and assessment of mitigation and adaptation options. The study advises that exogenous climate interventions need to be congruent with indigenous based strategies to avoid maladaptation. To the climate research community therefore, it should be realised that IK is useful both as leads and as baseline knowledge for future work on the impacts of climate change, and in the assessment of climate interventions. In this regard, the remaining challenge is to formulate a framework of constructive dialogue between indigenous scientists and conventional scientists so as to make sure that the mutual benefits of the two knowledge forms are adequately harnessed. Handled well, such collaborative effort would ensure enhanced climate change knowledge for successful mitigation and adaptation strategies. Handled poorly, there is a risk that the developmental needs of communities exposed to climatic events would not be addressed.
- Full Text:
- Date Issued: 2014
Influence of laser surface treatment on residual stress distribution and dynamic properties in rotary friction welded ti-6al-4v components
- Authors: Tsikayi, Davies Shamiso
- Date: 2019
- Subjects: Lasers -- Industrial applications , Friction welding Pressure welding Metals -- Research
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/43823 , vital:37050
- Description: This manuscript details a study on laser surface treatment, a surface modification technique that is an easily flexible way of improving material surface properties of complex geometries. The research explored the potential of laser surface modification/treatment as a post welding surface processing technique for RFW Ti-6Al-4V ELI components by evaluating the microstructural effects, influence on fatigue life and the depth and magnitude of residual stresses induced. The outcome of this study reveals how post processing by laser surface modification affects crack initiation hence fatigue life and further explains mechanisms potentially contributing to enhanced joint properties. This study was accomplished by investigating the effect of laser surface treatment on surface properties of hourglass cylindrical rotary friction welded Ti-6Al-4V ELI specimens. Preliminary work was done in two stages. The first stage involved conducting laser surface treatment on 3 mm Ti-6Al-4V sheets. In this stage, an understanding of the process variables concerning the laser surface treatment process characteristics was established. Laser power and focus position were varied whilst scanning speed was kept constant. The observed macrographs were quantified in terms of laser penetration depth and width. A hardness and microstructural analysis was also conducted on selected specimens of the laser surface treated flat sheets trials. The second stage involved surface treatment of the hourglass fatigue specimen. This preliminary work allowed for the type and influence of treatment strategy to be analysed. The influence of treatment strategy on the depth of penetration was established with an emphasis on achieving homogeneity of the laser surface treated zone’s depth of penetration around the complete cylindrical specimen’s diameter. The final matrix involved varying laser power, scanning speed and focus position and the specimens were characterised by comparing hardness, residual stresses and microstructure. The results showed that laser surface treatment changed the hardness profile of the near surface of the specimen owing to the introduction of a homogenous microstructure at the surface as compared to a friction welded specimen. The microstructure was resolved using electron backscatter diffraction. A fully α-lamella microstructure was observed in the two specimens analysed at a position of 200 μm from the surface. The α-lamella had different width sizes with the low-power density specimen having a very fine microstructure as compared to that of the high-power density specimen. EBSD phase maps were also analysed for the parent, rotary friction welded only and friction welded laser surface treated specimens. The laser treated specimens showed virtually no β phase present as compared to the parent and rotary friction welded only specimens. LST processing improved the fatigue properties of the RFW specimens. The position of failure shifted from the HAZ to outside the RFW joint. This change in position was attributed to the surface modification by LST thereby introducing a more homogenous microstructure at the surface of the specimen. Additionally, it was also observed that the power density had an important role to play in the fatigue properties of the laser surface treated specimens. The high-power density LST specimens had a low fatigue limit compared to the low-power density specimens. The low fatigue limit at high- power density correlated with the residual stress results where the high-power density specimen had the highest attained surface tensile axial residual stresses. In conclusion, the main influences of laser surface treatment of small friction welded Ti-6Al-4V ELI components relate to an increase in fatigue properties by shifting crack initiation sites to less stressed areas. In this way, laser surface treatment could assist in the optimisation of manufacturing methodologies for small near net shape complex geometry components. The uniform and homogenous microstructure eliminates or reduces microstructural variations as observed in as welded components, reducing weld zone hardness variation. Additionally, the study showed that the introduction of a near surface refined microstructure inhibited crack initiation in the welded region.
- Full Text:
- Date Issued: 2019
Influence of process energy on stress corrosion susceptibility of a friction hydro pillar repaired steam turbine rotor disc blade locating hole
- Authors: Pentz, Willem Gerhard
- Date: 2020
- Subjects: Friction welding , Mechanical engineering
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/47106 , vital:39810
- Description: Currently the power generation industry is struggling to keep older coal power plants running efficiently. One of the major hurdles is to keep repair and service cost low. Over time stress corrosion cracking (SCC) occurs in the locating pinholes of tier type rotors which locate the turbine blades. This is where this research aims to assist with an alternative repair technique, Friction Hydro Pillar Processing (FHPP) welding, to have longer service intervals thus saving cost and time. The same material can be used for welding and a new aligned hole can be drilled. FHPP welding is a solid state friction welding process. Four different FHPP axial forces were selected to compare their respective performance in subsequent tensile testing, impact testing and SCC testing. All the tensile samples extracted from preheated welds and post weld heat treated welds fracture in the parent material, which indicates good weld efficiency. The impact crack route from the weld nugget towards the parent material was identified in the energy and force graph. Axial force which promote impact toughness can be selected with this curve. SCC occurs when a tensile stress is applied to a susceptible material when in a conducive environment for cracking. A new SCC W-shape was designed and performed well during initial testing. With the SCC W-shape two specimens can be extracted opposite each other and tested. Both the preheated weld samples and the post weld heat treatment (PWHT) weld samples had improved SCC performance over their respective parent material samples. A high axial force, low process energy, and high process energy rate (low process energy and low weld time) produced a weld with improved SCC resistance. FHPP (with PWHT) is a promising repair technique as it improved on the SCC resistance and impact toughness as well as having 100% bond efficiency. More research is still required to identify the SCC mechanism of the FHPP weld.
- Full Text:
- Date Issued: 2020
Influence of the macro-economic environment on the construction sector's contribution to the South African economy, 1984 to 2011
- Authors: Babalola, Adewumi Joseph
- Date: 2016
- Subjects: Construction industry -- Economic aspects Economic development Environmental economics
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/5618 , vital:20916
- Description: The construction sector serves as the engine of growth to the South Africa economy because of its catalytic role in the growth and development of the country. This study focuses mainly on the influence of the macro-economic environment on the contribution of the private sector to construction in the South Africa economy from 1984 to 2011. Government construction work is considered to be an injection into the economy; in this regard, state construction is regarded as public investment in the economy; and therefore, it is anti-cyclic (Keynes, 1936). The aim of this study has been to develop an econometric model for predicting the influence of the macroeconomic environment on the contribution of the private sector to the construction sector in the South Africa economy. The research design adopted in this study was an “ex-post facto” type, otherwise known as a causal-comparative design. The data were extracted from the published sources of the South African National Statistics, namely SARB, Stats SA and Quantec SA. The estimation technique used in this study was the ARDL model using quarterly data from 1984 to 2011. This is because in the construction sector, the influence of the independent variables is always felt over time – rather than all at once. The results of this study show that there is a long run causal relationship between inflation rate, interest rate, real exchange rate, GDP and gdp in the construction sector. The descriptive statistical analysis shows that there is a negative relationship between variables inflation rate and interest rate and the private sector spending in construction. However, economic growth as well as growth in the construction sector has a positive relationship with the private sector spending in construction. Likewise, the real exchange rate and labour productivity in construction have a negative relationship with the private sector’s spending in construction and they are statistically insignificant. The variance decomposition analysis show that the private sector spending in construction explains about 75 per cent of it variations, followed by inflation rate that explains 21 per cent on the average; while the remaining variations, comprising about 4 per cent, were shared among the other independent variables, such as GDP, GDP in construction, the interest rate and the real exchange rate. It was discovered that only the inflation rate does Granger-cause the private sector spending in construction. From the finding it can be concluded that inflation rate is a significant explanatory variable in explaining the variation in the dependent variable during period under review. Policy recommendations are as follows: firstly, the monetary authorities in South Africa should embark on sound policies that would bring about low prices of the construction materials. This would ensure growth and development in the construction sector; secondly, a stimulating development plan that would encourage private sector investment in properties and infrastructural development must be instituted; thirdly, an alternative policy to the present inflation targeting is recommended that would bring about low inflation, high growth, low unemployment and stable exchange rate; fourthly, the present policy on interest rate must be reviewed to allow for more participation in construction projects by the private sectors of the economy; fifthly, due to the fact that fluctuation in the crude oil prices in the international market is one of the major factors causing high inflation rate in South Africa, government must source local alternative products that would bring down prices of construction materials.
- Full Text:
- Date Issued: 2016
Influences on construction project delivery time
- Authors: Olatunji, Aiyetan Ayodeji
- Date: 2010
- Subjects: Construction industry -- South Africa -- Management , Project management -- South Africa , Construction industry -- Economic aspects -- South Africa , Construction industry -- Technological innovations -- South Africa , Construction industry -- Labor productivity -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9681 , http://hdl.handle.net/10948/1548 , Construction industry -- South Africa -- Management , Project management -- South Africa , Construction industry -- Economic aspects -- South Africa , Construction industry -- Technological innovations -- South Africa , Construction industry -- Labor productivity -- South Africa
- Description: Construction delays are a global phenomenon. Factors causing construction delays in construction projects differ from country to country, due to different prevailing conditions. The prevailing conditions that could exert an influence on project delivery time are: political, economic, and physical factors as well as level of technological development; management style, and construction techniques. The construction industry is a major player in the economy, generating both employment and wealth. However, many projects experience extensive delays and thereby exceed initial time and cost estimates. This study aims at determining the causes of delays in project delivery in South Africa; evolving interventions, and developing a model for the delivery of projects on time. Inferential and linear regression statistical tools were used in the analysis of data for the study. The sample population consists of architects, builders, quantity surveyors, structural engineers, and clients, and the metropolitan cities of five provinces constituted the geographical delimitation of the study. The provinces are: Eastern Cape; Free State; Gauteng; KwaZulu-Natal, and Western Cape. The metropolitan cities are: Bloemfontein; Cape Town; Durban; Johannesburg, and Port Elizabeth. Findings which negatively influence project delivery time in South Africa include the following: lack of adequate planning; management style; the lack of constructability reviews of designs; inadequate motivation of workers; economic policies; lack of prompt payment to contractors, and quality of management during design and construction. Recommendations include: (1) The introduction of the following courses in built environment tertiary education � quality management competences; operational planning; design management, and generic management; (2) pre-qualification of suppliers; (3) inclusion of the following in tender documentation � human resource schedule; plant and equipment schedule; quality assurance plan, and work schedule; (4) appointment of materials specialists on a large projects; (5) the model developed should be adopted for use in the South African construction industry for the delivery of projects on time, and (6) the linear regression equation: Y = 13.1159 + 1.1341x or 35.3 percent addition on time for the estimation of project delivery time.
- Full Text:
- Date Issued: 2010
Innovation: its impact on the success of construction micro, small, and medium enterprises in northern Nigeria
- Authors: Tsado, Abel John
- Date: 2019
- Subjects: Construction industry -- Nigeria , Business enterprises -- Nigeria Success in business -- Nigeria Economics—Environmental aspects
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/44951 , vital:38191
- Description: There is growing recognition of the important role Construction Micro, Small and Medium Enterprises (CMSMEs) play in economic development. In 2013, Nigeria had about 36,994,578 Micro, Small, and Medium Enterprises (MSMEs) and 731,303 CMSMEs, about 1.99% of the total number of MSMEs in the country. However, 50% of CMSMEs in Nigeria close down within their first five years of existence. Consequently, only about 10% of CMSMEs in Nigeria survive, thrive, and grow to maturity. Enterprises failing within so short a time, portend a huge problem surrounding CMSME innovation and success. While literature seems to indicate innovation as the likely way out of CMSMEs failure, few researchers have considered the connection between CMSMEs innovation and their success. Hence, this research aimed to explore the effect of innovation(s) and innovation systems on the success of the Northern Nigerian CMSMEs. The research objectives were: to identify the types of innovation that are predominant in/peculiar to the Northern Nigerian CMSMEs; to determine how the types of innovation impact the success of the Northern Nigerian CMSMEs; to establish what the innovation systems that manage the innovation of the Northern Nigerian CMSMEs are; and, to determine how the innovation systems, promote innovation among the Northern Nigerian CMSMEs. Qualitative research method was utilised; consisting of 17 recorded interviews within Northern Nigerian which is the study area. The interview also employed structured interview guide, comprising structured open-ended questions to ensure consistency and rigour in the data collection process. The research adopted two stage non-probabilistic sampling, comprising judgmental and snowballing sampling for stage one and two respectively. In stage one, participants were drawn judgmentally based on their innovation and in stage two, the sample size was expanded, using a snowballing sampling technique where the participants in stage one suggested other participants who had also been innovative. Data collected were transcribed and open coded, while the codes for innovation types, and innovation impact on CMSME success were developed with the aid of a deductive code earlier developed from literature. The code occurrences were determined and categorised, and themes were developed. These themes were then subjected to interpretation and analysis. The research findings indicate that the predominant type of innovations within the CMSMEs in the northern part of Nigeria are product innovation, management innovation and service innovation. In addition, there are, technological application innovations, logistics innovations and labour innovations. These innovations impact on the profit, capital, customers, workers and the products of the CMSMEs studied. The innovations are responsible for the CMSMEs success periods, reasons for success and their salient points of success. Therefore, the research concludes that innovation impacts on the studied CMSMEs success. Consequently, the research achieved its aim. The study also discovered an absence of systems that support the innovation of CMSMEs in the northern part of Nigeria. Through this research, an innovation system framework has been developed and it is recommended that it be implemented because of the observed lack of innovation systems in Nigeria.
- Full Text:
- Date Issued: 2019
Integrating sustainability dimensions into construction labour productivity determinants in Zimbabwe
- Authors: Moyo, Tirivavi
- Date: 2020
- Subjects: Construction industry -- Labor productivity -- Zimbabwe , Construction workers -- Zimbabwe Construction industry -- Employees -- Zimbabwe Construction industry -- Management
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/46207 , vital:39514
- Description: Low construction labour productivity and inadequate welfare of construction workers is a compound challenge in Zimbabwe. This challenge is due to shortcomings situated in the Decent Work Agenda. Whilst a plethora of contributory factors exists, those that affect the Zimbabwean construction industry were identified for interrogation. Therefore, the study aimed to improve and sustain construction labour productivity in Zimbabwe through fulfilling significant decent work substantive elements, in consideration of demographic variables of stakeholders. A cross-sectional survey research strategy was utilised with quantitative data being collected from selected respondents through the use of questionnaires. The population for the study consisted of randomly selected construction companies registered with the Construction Industry Federation of Zimbabwe and based in Harare, Bulawayo and Shurugwi where site managers’/project managers’ participated. Construction skilled and semi-skilled workers on thirteen (13) construction sites, situated within the same study area, participated in the study. Educators from technical and vocational training institutions and respondents from relevant regulatory bodies were also selected to participate in the study. Quantitative data analysis methods which included Pearson chi-squared tests, Mann-Whitney U tests; Kruskal-Wallis tests, Pearson bivariate correlation method and Regression analysis were utilised. Demographic variables (age, gender, designation, educational levels and experience) were utilised to determine the existence of statistically significant differences in respondents’ perceptions. Construction companies are encouraged to implement corporate social responsibility strategies through equipping workers of different educational levels with knowledge and skills that can be transferred to and benefit themselves and their communities. Adequately trained construction workers best serve their communities through improving their livelihoods, improved safety and health consciousness and quality workmanship. People centred management aspects were found to be fundamental within construction sites as they promote the welfare of workers and should precede any productivity improvement drives. Technical and vocational training institutions need to inculcate sustainability learning objectives within their curricula if any meaning strides in enhancing welfare and productivity of workers is to be achieved. Also, establishing structured on-the-job training that incorporates sustainability learning objectives to achieve workers’ safety on sites is essential. There was a consensus that working conditions must ensure the welfare of workers first before any productivity gains can be realised. Provision of acceptable decent working conditions for different designations and educational levels was encouraged. A comprehensive model was developed for sustaining construction labour productivity that included statistically significant regression models and derived statistically significant demographics from construction labour productivity determinants under study. Validation of the regression models was undertaken through cross-validation and comparison with existing theory. Tenable labour productivity performance measurement and reporting must be inclusive of decent work accomplishments. Short-term interventions that include awareness campaigns and provision of adequate working conditions are required for project-based resolutions whilst, long-term interventions are required where structural reforms within the training of skilled, semi-skilled workers and managers are required, for continuous improvement.
- Full Text:
- Date Issued: 2020
Integration of indigenous knowledge in the intermediate phase school curriculum in a selected education district in the Eastern Cape, South Africa
- Authors: Mkosi, Nkosinathi Ndumiso Lizo
- Date: 2019
- Subjects: Education -- Curricula -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/16136 , vital:40671
- Description: The aims and principles of the post-apartheid South African school curricula, ranging from the Revised National Curriculum Statement Grades R-9 and the National Curriculum Statement Grades 10-12, to include the Curriculum and Assessment Policy Statements (Grades 1-12), have been aligned with the aims and principles of the South African Constitution. The aims and principles, among others, speak to the establishment of human rights, inclusivity, environmental and social justice, and valuing of indigenous knowledge systems. These are the bedrock of all the subjects and do not necessarily confine themselves to the science subjects only; even though the call of inclusion of indigenous knowledge in the sciences is oversubscribed. There has been concerns raised variously that the integration of indigenous knowledge systems in the curriculum, generally, and in the teaching of the respective subjects, particularly, does not necessarily happen as it should be. Thus, the purpose of this mixed methods approach study that adopted a concurrent triangulation mixed methods design and premised on the postpositivist paradigm investigated the integration of indigenous knowledge in the Intermediate Phase school curriculum in a selected Education District in the Eastern Cape Province, South Africa. The guiding lenses adopted for this study were two-fold. The main primary theoretical framework drew from three integration theories: (a) Huang and Newell’s (2003) Knowledge Integration Processes and Dynamics notions; (b) Beane’s (1995) Curriculum Integration and the Disciplines of Knowledge and (c) Harden’s (2000) Integration ladder: A Tool for Curriculum Planning and Evaluation. The ‘secondary’ lens of analysis, which the researcher named, the ‘supplemental framework’, was constituted by notions and constructs derived from the indigenous knowledge systems discourses and postcolonial notions and constructs. The study revealed, among other findings, that (i) whilst a majority of teachers claimed to integrate IK in their classrooms, a significant number did not, and those who claimed to be integrating were unsure about how to integrate (ii) the majority of teachers, HoDs and Subject Advisors were either poorly trained or did not receive any training in the integration of IK (iii) the support and monitoring of IK integration was poor to non-existent. Thus, the study proposes a model, the Integrative Indigenous Knowledge Integration Support and Monitoring Model (IIKISMM), which may act as a framework for the coordination of the support and monitoring of IK integration in the school curriculum. There are significant recommendations offered by the study to teachers and policy makers with regards the integration of indigenous knowledge systems in the school curriculum. Also offered by the study are possibilities for further research in the integration of indigenous knowledge system in the curriculum.
- Full Text:
- Date Issued: 2019
Integration of values into management of learners' discipline in Ugandan schools
- Authors: Sekiwu, Denis
- Date: 2013
- Subjects: School management and organization -- Uganda , School discipline -- Uganda
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9583 , http://hdl.handle.net/10948/d1020814
- Description: To make education a profitable enterprise and contributor to social development requires that schools infuse values into schooling as part of the ethical construction of learners and citizenship building. This research used Kampala district as the case study to conduct a qualitative inquiry with grounded theory to examine the integration of values into the management of learners’ discipline in Ugandan schools. Using a sample of 60 participants, the researcher gathered data using personal interviews, focus group interviews, and documentary analysis. Through the analysis of this data, the researcher established that the School Governing Body (SGB), government, educators, missionaries and the community are stakeholders highly involved in directing the process of values integration into learners’ discipline. He also discerned that different schools impart moral, spiritual, academic, aesthetic, social and universal values into the learners. However with the 1963 Castle Report on Education that led to the nationalization and secularization of schools, denominational schools strongly felt that government robbed them of their powers to control and manage schools through the “principle of subsidiarity”. This seems to have led to the gradual erosion of values and breakdown of discipline in the denominational schools as well as the others. The central argument of this thesis is that integrating values into school discipline in Uganda would result into an inclusive education system that supports both theist and atheist attitudes towards formal schooling. Some respondents argued that values should be directly integrated into learners’ discipline while others opposed values integration. Those who supported values integration into school discipline pointed out that it is an integral part of life-education. On the other hand, those who oppose integrating values argued that values integration might be misused to impose secular influences on the learners. The existing avenues of optimal integration of values into school discipline include use of physical punishment and restorative justice, although custodial methods are widely condemned by human rights activists for being too harsh, punitive and retaliatory. Restorative justice methods used include the use of religious and social clubs as well as counseling and guidance. Collective stakeholder participation in school management is also widely used where school management, government, parents and the community take on a collaborative role in empowering and creating an environment for positive discipline. Finally, missionary educators play a significant role in learners’ behavioural modification. The challenges of values integration into school discipline, on the other hand, are policy-related; including poor school administrative styles, failure to define which values to emphasize in disciplinary management, lack of staff motivation and educators’ unethical behaviour. The classroom-related challenges were an over emphasis on academic values that, consequently, turn education into a theoretical rather than a practical exercise. This is compounded by the poor teaching methodologies used like rote-learning due to the problem of dealing with large classes especially in UPE and USE schools and the strict emphasis on an examination-centered syllabus. The social-related challenge observed was the negative influence of the media on young people’s life styles, consequently, leading to permissiveness, aggressive, violent and militant behaviours now common in schools. The study underscored the need to emphasise stakeholder responsibility in school disciplinary management, and the necessity to offer visionary and collegial leadership, identify a common set of values critical to the promotion of life-long learning, promotion of life-education to ensure formation of morally upright learners, and encourage inclusive education (UBUNTUISM). Government should draft a national education philosophy to guide schools in integration of values education, emphasizing secular, moral and religious values, as well as the need for restorative justice, and employing more pragmatic teaching methodologies. There is also the need to create role-models and staff motivation. All these are cardinal remedies in ensuring constructive school discipline. Finally, the central theory that explains the integration is an Integrated Values Framework (IVF) for Positive Discipline (PD). It advocates that discipline is a process of nurturing learners through the provision of inclusive education, life-long learning and citizenship building.
- Full Text:
- Date Issued: 2013
Interest rate liberalisation and economic growth in SADC countries
- Authors: Moyo, Clement Zibusiso
- Date: 2018
- Subjects: Southern African Development Community , Economic development -- Africa, Southern Developing countries -- Economic conditions
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/22791 , vital:30087
- Description: The pioneers of financial liberalisation, McKinnon (1973) and Shaw (1973) argue that inter-est rates determined by market forces have a positive effect on economic growth rates. Inter-est rates that are kept at low levels through the intervention of a central bank discourage sav-ings and capital accumulation, and distort the allocation of resources. Interest rate liberalisa-tion results in higher real interest rates which could have a positive effect on savings, invest-ments and economic growth (Ang & McKibbin 2007). Interest rate liberalisation also reduces capital flight and encourages capital inflows by increasing return for investors which supple-ments domestic investments. Shaw (1973) argued that interest rate liberalisation promotes financial development by encouraging savings and increasing the availability of funds for lending purposes. The study provides an empirical analysis of the channels through which interest rate liberalisation impacts on economic growth in SADC countries for the period 1990 to 2015. The study is motivated by the concerns on the impact of interest rate liberalisation on eco-nomic growth in the period after the 2008-’09 global financial crisis as well as concerns that interest rate liberalisation increases the likelihood of financial crises. Higher interest rates resulting from interest rate liberalisation may increase the likelihood of financial crises by encouraging risk-taking on the part of banks in an attempt to take advantage of higher returns. Authorities in most countries have reduced interest rates in an attempt to boost aggregate demand, which is expected to speed up the recovery from the crisis. However, the lowering of interest rates may result in a decrease in savings and investments, which are the main drivers of long-term economic growth. Real interest rates below equilibrium may encourage banks to take more risks in their lending practices in order to earn higher returns which may result in an increase in non-performing loans. The influence of interest rates on financial crises has thus received considerable attention since the onset of the 2008-’09 global financial crisis and this thesis contributes to the literature by determining how interest rates impact on economic growth in SADC countries and whether interest rate liberalisation increases the likelihood of financial crises. The study examines the relationship between interest rate liberalisation and economic growth through different channels. These include savings and investments, capital flows and finan-cial development. The study uses the Pooled Mean Group (PMG) estimator proposed by Pesaran et al (1999) to estimate the effect of interest rate liberalisation on economic growth through the abovementioned channels. The study also examines whether interest rate liberalisation increases the likelihood of financial crises. This is estimated using the logit model, due to the binary nature of the dependent variable. The results provide limited support for the McKinnon and Shaw hypothesis. Interest rate liberalisation has a positive effect on economic growth through higher savings and investments. Interest rate liberalisation has a positive outcome on capital inflows, which indicates that the prospect of earning higher returns encourages foreign investors to invest in the domestic economy. However, capital inflows do not enhance economic growth. This could be due to the low levels of human capital in SADC countries. Interest rate liberalisation boosts financial development through higher savings and invest-ments. However, financial development has a negative effect on economic growth because of the link between financial development and financial crises. The results show that interest rate liberalisation decreases the likelihood of financial crises directly, however, it increases the probability of financial crises indirectly through financial development. This suggests that the major cause of financial crises in the region is the low levels of institutional quality and lack of adequate supervisory frameworks to monitor the functioning of the financial system. Therefore, the results imply that the negative impact of interest rate liberalisation may outweigh the positive effect of higher savings and investments in SADC countries. A number of policy recommendations can be drawn from the study. Liberalisation of interest rates has a positive effect on economic growth through savings and investments. However improving the levels of institutional quality is vital for preventing financial crises. Interest rate liberalisation may not have a direct influence on financial crises, but higher levels of fi-nancial development emanating from higher interest rates increase the likelihood of financial crises. Therefore, a sound monitoring framework is necessary for the benefits of financial liberalisation to be realised. Also, investment in education, training and research and development is a necessity so as to increase levels of human capital, which in turn may allow the region to reap the benefits of capital inflows.
- Full Text:
- Date Issued: 2018
Investigating emerging deleuzoguattarian connections to the environment via information technology
- Authors: Siwak, Jakub
- Date: 2016
- Subjects: Mass media and the environment , Neoliberalism
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/8329 , vital:26343
- Description: This thesis explores whether or not it is possible to positively inflect – via digital means – people’s orientations toward nature through connecting their duration to the time of animals. The thesis opens with an overview of the contemporary environmental crisis, mapping related significant discourses, events and responses from the early 1960s onward. In this regard, after thematizing the relatively ineffective global institutional response to the environmental crisis to date – in spite of both consistent criticisms proffered by a range of stakeholders and widely available information on the scope of current environmental degradation – the lack of any concerted effort to deal with this issue is accounted for in terms of the dimensions of what Kilbourne, Beckmann and Thelen refer to as the ‘Dominant Social Paradigm’ (DSP). However, it is argued that of these dimensions, the technological dimension is most amenable to pro-environmental inflection, particularly through recent developments within information technology. That is, despite the latter being the privileged technology of neoliberalism, and despite the environmental cost of its current material infrastructure, it is also highly unlikely that societies will abandon their dependence on information technology in the near future. Given this, the importance of considering how such technology can be harnessed to positively re-orientate users’ perceptions of the natural world, in a way that also avoids the pitfall of technophilia, is advanced. In terms of this, both positive and negative appraisals of information technology by prominent new media theorists are discussed, and information technology is put forward as a tool that remains indeterminate in terms of its use. After this, and with a view to exploring how the technological dimension of the DSP might possibly be inflected in a pro-environmental manner, the thesis draws on the works of Gilles Deleuze and Félix Guattari who promote desire and difference outside the ambit of capitalism, particularly through desubjectivation in relation to their concept of ‘becoming-animal.’ Finally, after dealing in addition with some potential theoretical challenges to the application of Deleuze’s ideas within the digital realm, focus shifts to three contemporary digital artefacts which have the capacity, albeit to varying degrees, to facilitate a becoming-animal. In this regard, a distinction is made between those artefacts that precipitate first-, second- and third-order hybrid durationality, and it is argued that the latter category presents the greatest promise of interfacing the time of humans with the time of animals.
- Full Text:
- Date Issued: 2016
Investigating the impact of a psychometric assessment technique in the South African automotive industry
- Authors: Piro, Karen
- Date: 2011
- Subjects: Automobile industry and trade -- South Africa -- Employees -- Ability testing , Automobile industry and trade -- South Africa -- Employees -- Training of
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9397 , http://hdl.handle.net/10948/1381 , Automobile industry and trade -- South Africa -- Employees -- Ability testing , Automobile industry and trade -- South Africa -- Employees -- Training of
- Description: This research takes place in a South African multinational automotive industry, which needs to be on the forefront for being globally competitive and sustainable to remain viable in the country. A strategic initiative was embarked upon to identify talent within their staff population, through the psychometric assessment of learning potential. The objective was to identify high potential employees and provide them with the requisite training and development to meet the demands of the rapidly advancing technology. The primary purpose of this study is to investigate the usefulness of the Ability, Process of Information and Learning Battery (APIL) as a psychometric assessment tool for identifying talent, within a heterogeneous workforce. This research adopts a cross-cultural approach as it is comparative in nature and addresses the adequacy of a psychometric instrument in a multicultural context. The Employment Equity Act has transformed the landscape of the use of psychological measurement in South Africa, in that it stipulates that no psychological test that is biased against any cultural group can be used. A sample of 841 heterogeneous staff employees was assessed with three major research objectives: (a) to ensure that the instrument could stand scientific scrutiny thereby complying with the Employment Equity Act; (b) to recommend ways the organisation can identify and understand employees’ talent more holistically; and (c) to manage talent more effectively. The heterogeneous sample was divided into six homogeneous subsets for statistical analysis. This research attempted to answer the first objective through the examination of internal consistency, bias and equivalence of the APIL. Results showed good internal consistency, very good construct equivalence and low item bias, demonstrating the APIL can be applied fairly in a multicultural industrial setting. The second objective was determined by investigating whether significant difference in mean learning potential scores occur among the identified subsets in the sample. Statistical analyses provide clear trend lines indicating that sociopolitical and socioeconomic factors of advantagement and disadvantagement, age and education influence learning potential. However it is also evident that there are individuals across all subsets that demonstrate strong cognitive potential. This supports the rationale on which the APIL was developed, in that it distinguishes people with high learning potential despite the fact that there may be gaps or limitations in skill repertoire due to past disadvantagement. Recommendations to address the third objective is provided by aligning learning potential with the performance management system to provide a holistic overview of the talent composition. This will assist in the identifying of strategic training and development interventions needed at the individual, functional and organisational level, which is key for the South African automotive industry to remain competitive and viable.
- Full Text:
- Date Issued: 2011
Investigation of the NFC technology for mobile payments and the development of a prototype payment application in the context of marginalized rural areas
- Authors: Gurajena, Caroline
- Date: 2014
- Subjects: Mobile commerce -- South Africa Mobile communication systems -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/14071 , vital:39802
- Description: The Internet of Things (IoT) environment involves the interaction of numerous ‘things’. These ‘things’ are embedded with different kinds of technologies such as RFID technology, NFC technology and sensors. This causes IoT to bring into play many security risks apart from the ones that already exist in the current Internet, for example, embedded RFID tags can be easily triggered and send their content which could be private information. IoT also introduces internal attacks such as on-off attack, bad mouthing and white washing attacks into networks that already exist. These internal attacks cannot be solved by hard security mechanisms such as cryptographic algorithms and firewalls because they guarantee total trust. This eliminates uncertainty which should always be available where trust exist. That is, hard security mechanisms enable IoT ‘things’ to either trust another ‘thing’ completely or not and this makes them unsuitable for the IoT environment. When objects in any network are communicating, there is some element of uncertainty. Also, hard security mechanisms such as public key cryptography cause communication overheard in the already resource-constrained IoT devices and these conventional cryptography methods cannot deal with internal attacks. This brings about the need for a middleware that includes functions that will manage trust, privacy and security issues of all data exchange, communications and network connections. For IoT to be successful, the provision of trust, security and privacy measures are essential. Trust management may enhance the adoption and security measures in IoT. Trust helps in identifying trustworthy ‘things’ in the network and give ‘things’ in the network the ability to reason in all aspects concerning trust in the environment. Trust can be administered through a trust management model. This research notes that most of the trust models that have been proposed fail to address scalability challenges and lack suitable computation methods. It is on that premise that this research focuses on developing a suitable trust model for the IoT environment. The research also introduces new ways of creating relationships in IoT. This enables the creation of new cooperation opportunities in the environment. In overall, this research aimed to design and develop a generic trust and authority delegation model for the heterogonous IoT environment that is scalable and generalized to cater for the heterogeneous IoT environment. This research was conducted in three phases. The first phase reviewed literature in order to identify outstanding issues in IoT trust management and also identify the suitable computational method. This provided a critical analysis of different computational methods highlighting their advantages and limitations. In the second phase of the research, the proposed trust model was designed and tested. In the last phase, the feasibility of the proposed model was evaluated. The proposed model is based on fuzzy logic. Fuzzy logic was selected for trust computation because it is able to imitate the process of the human mind through the use of linguistic variables and it can handle uncertainty. The proposed model was tested in a simulated environment. The simulation results showed that the proposed model can identify selfish and malicious entities effectively. The results also showed that the model was able to deal with different types of behaviours of entities. The testing proved that the proposed trust model can support decision making in IoT based on trust. The results from the evaluation show that this research ameliorates the design and development of trust management solutions for the IoT environment.
- Full Text:
- Date Issued: 2014
Investigation of the potential separation of isomers and related compounds using host compound (2R,3R)-(−)-2,3-dimethoxy-1,1,4,4-tetraphenylbutane-1,4-diol
- Authors: Pohl, Pieter Lourens
- Date: 2018
- Subjects: Chemistry, Organic , Clathrate compounds Thermal analysis
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/23131 , vital:30432
- Description: In this study, we investigated the potential of a host compound, (2R,3R)-(−)-2,3-dimethoxy-1,1,4,4-tetraphenylbutane-1,4-diol (DMT), for use in the separation of isomers and related compounds using host-guest chemistry. The title molecule, DMT, is composed of a butane chain bearing hydroxyl moieties on the terminal carbons and methoxy moieties on the two internal, chiral carbon atoms. In addition, there are two phenyl rings on each of the terminal carbons. The synthesis of DMT was carried out by subjecting the diester of naturally-occurring optically active tartaric acid to a Grignard reaction employing phenylmagnesium bromide. Subsequent methylation of the secondary hydroxy groups with dimethyl sulfate afforded DMT. The resulting host molecule was investigated for its inclusion abilities by crystallizing with a number of potential aromatic, aliphatic and alicyclic guests such as toluene, aniline, nitrobenzene, anisole, cyclohexane, ethyl acetate and ethanol. Host:guest ratios were determined by means of 1H-NMR spectroscopy. Of the hosts investigated, DMT favoured a host:guest ratio of 2:1 for all included guests investigated. It complexed with most non-polycyclic aromatic guests as well as cyclohexane, cyclohexene and cyclohexanone. It was not able to include short chain or branched alcohols such as methanol, ethanol or 2-propanol, or other hetero-aliphatic or hetero- cyclic compounds such as diethyl ether, acetonitrile, morpholine or dioxane. Competition inclusion experiments were performed in which DMT was crystallized from equimolar and non-equimolar binary, ternary and quaternary mixtures of appropriate guests. The mother liquor mixtures and resultant crystals were subjected to GC-MS analysis in order to determine whether DMT showed discriminatory behaviour towards the guests from a mixture. It was observed that DMT was able to differentiate between related compounds, for example, the host preferred to include N,N-dimethylaniline compared with N-methylaniline and aniline. The host also discriminated against isomers, for example, p-xylene was preferentially included over o-xylene and m-xylene, while o-cresol was included in preference to p-cresol and m-cresol. Single crystal X-ray analysis was used to investigate the host–guest interactions responsible for guest inclusion, as well as to discern reasons for the host’s selective behaviour. X-ray data for the inclusion complexes indicated that each complex was isostructural, crystallizing in the monoclinic C2 crystal system. A pair of 1,3- and 2,4- intramolecular hydrogen bonds, as well as intramolecular non-classic hydrogen bonds between adjacent ortho-aromatic hydrogens and hydroxy moieties was a significant stabilizing factor for the geometry of the host. Guests were held within discrete cavities in the crystal lattice, and experienced only π–π stacking, CH–π interactions and other short contacts. Thermal analyses were used to determine the relative thermal stabilities of the complexes, and these data compared to the selectivity preference of DMT, obtained from the competition experiments, in order to assess the reasons for any discriminatory behaviour. Finally, Hirshfeld surface analysis data was used to determine if the thermal stability of the complexes was related to the number and type of interactions between host and guest.
- Full Text:
- Date Issued: 2018
Investigation of the thermo-chemical behaviour of coal-algae agglomerates
- Authors: Baloyi, Hope
- Date: 2018
- Subjects: Biomass energy , Coal -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/23913 , vital:30642
- Description: There is a growing research interest in the co-processing of biomass and coal, with the aim of addressing the negative attributes associated with the thermal processing of coal alone. Biomass feedstocks are regarded as a clean, renewable source, and the co-utilization of biomass feedstocks with coal is deemed to have a potential to reduce emission of pollutants (i.e. NOx and SOx) and volatile organic compounds (VOC’s). Moreover, biomass are thermally reactive and thus facilitate the conversion of coal during co-processing. Biomass material and coal are two autonomous fuel materials with different chemical characteristics and have a dissimilar thermal behaviour making it difficult to achieve chemical interaction between the two solid fuels to contribute to the formation of products. Coalgae® Technology developed at the Nelson Mandela University, involves the biological treatment of coal fines by adsorbing live microalgae biomass (in slurry form) onto waste coal fines to form coal-microalgae agglomerates. This new innovative approach seeks to integrate bio-based feedstock into coal thermal processing and to improve the utilization and thermal efficiency of coal fines as well as the interaction between the volatile components of biomass and coal during thermal processing (e.g. devolatilization), thereby overcoming some of the challenges that confront the co-processing of coal and biomass. Coal fines are low-ranked coals, generally characterized by high contents of sulphur, high ash yields, low calorific values and poor thermal reactivity, and these attributes limits the thermo-chemical processing of the coal fines. Therefore, this investigation was undertaken to assess the thermo-chemical behaviour of coal-microalgae agglomerates, formed by adsorbing live microalgae slurry at varying ratios onto coal fines. For this purpose, the effects of adsorbing microalgae at varying ratios on the chemical characteristics and thermal behaviour of coal fines under pyrolytic conditions were investigated. The primary aim was to assess whether the thermo-chemical behaviour of coal-microalgae agglomerates, formed by adsorption of live microalgae onto fine coal, is substantively modified compared to a simple additive model of the original coal and pre-dried microalgae biomass samples. Results obtained from the proximate analyses performed on an Eltra Thermo-gravimetric analyzer (TGA) thermostep, have shown that the adsorption of microalgae slurry onto coal fines does not possess greater influence in improving the yield of volatiles and ash in coal fines than can be expected from a simple additive model of the original raw materials. Based on the ultimate analyses results, it was found that the adsorption of microalgae slurry resulted in a systematic reduction in the sulphur content, a notable increase in the hydrogen and oxygen contents, however, no significant disparities were found between the measured ultimate properties of coal-microalgae agglomerates as compared to the theoretically-expected ultimate properties from a simple linear combination of parental coal and microalgae biomass. Assessment of the thermal behaviour of parental samples and coal-microalgae agglomerates involved the use non-isothermal (40-900ºC, 20 K/min) thermogravimetry under inert conditions. It was found that the adsorption of microalgae slurry onto coal fines resulted in an improved thermal reactivity of coal fines, although, did not affect the overall pyrolysis characteristics of the coal fines. Comparison of the thermal profiles (measured and calculated TG/DTG curves), revealed that the yield of volatile products during the pyrolysis of coal-microalgae blends do not exceed the expected volatile yields from a simple combination of coal and microalgae biomass. These results suggest that there was no positive or accelerative synergistic interaction between volatile components of adsorbed microalgae and coal fines during pyrolysis. Mild pyrolysis of raw coal and coal-microalgae performed in a fixed-bed reactor furnace (450ºC), resulted in improved yields of Fossil-Bio crude (FBC) oil (derived from coal-microalgae pyrolysis), at increased biomass ratio compared to coal tar. FBC Oil was found to contain relatively high contents of oxygen, hydrogen, and low sulphur content than coal tar. GC-MS analyses showed the presence of a heterocyclic compounds (i.e. Indole and 2, 6 dimethyl pyridine) in the FBC oil and these were not identified in the coal tar. Furthermore, high boiling compounds such as Flourene, pyrene and pentacosane were identified in the coal tar, however not identified in the FBC oil. Simulated distillation results showed notable differences between the FBC oil and coal tar in terms of the distribution of boiling point fractions particularly, high boing point components. Semi-devolatilized chars derived from coal-microalgae agglomerates showed substantial degree of decarboxylation and dehydrogenation compared to the coal chars.
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- Date Issued: 2018