3. Electronic Theses and Dissertations (ETDs) - All submissions
Permanent URI for this communityhttps://wiredspace.wits.ac.za/handle/10539/45
For queries relating to content and technical issues, please contact IR specialists via this email address : openscholarship.library@wits.ac.za, Tel: 011 717 4652 or 011 717 1954
Browse
16147 results
Search Results
Item The affective black experience: struggles with conformity for young black professionals in corporate South Africa(2017-09) Bokala, Kutlwano TlameloSouth Africa’s democratic transition was cultured by, amongst others, the mythical ideology of Rainbowism. Rooted in happiness and the promises thereof, the renowned national metaphor was utilised by the state to radically shift the country’s narrative around nationhood towards a shared understanding of identity, belonging, citizenship, and diversity. Today, the influence of Rainbowism within state-led efforts towards social change has slowly deemed under much public scrutiny. Persistent poverty, inequality and violence have fostered the emergence of, what many are calling, an “End of the Rainbow” discourse. As integral and lurid entities within post-apartheid nation-building, black youth and institutionalised spaces have affected and been affected by the shortcomings of Rainbowism. Their shared history and intersecting significance in fuelling collective action amongst South Africans have been well depicted in recent times where youth-led movements have highlighted the inequality and unhappiness that exists in institutions spaces like the university. However, little mention has been made about how black youth are making sense of institutional life within spaces like the workplace, against the backdrop of promised happiness. Through the conversations had with eight young black professionals, this research report centres Rainbowism as a project of happiness that governs institutional life for black youth in South Africa. Happiness is revealed as a dominant discourse operating along axes of power that shape ‘happy’ employees based on various forms of corporeal differentiation.Item The eyes of the naked: what do the eyes of the naked see?(2018-11) Hermanus, LithaProtest literature is dead! Modify it or kill it, said many, including the likes of Professor Njabulo Ndebele and Justice Albie Sachs. At the dawn of the South African democracy, the latter is famously reported to have requested that, at the very least, the genre be sent into a five-year coma (Plummer, 1998). At its height, protest literature was criticised for its lack of creative depth and complexity. A ‘go-to’ for many African writers, it became too ubiquitous. Most of the genre’s authors produced works that were said to suffer from too much sameness. Their white characters were often predictably and typically oppressive, and their African ones were necessarily good. Among other recurring themes, existed political turmoil, violence, death and communities engaging in politically-charged funerals (Lockwood, 2008). Themes did not venture much beyond the struggle against apartheid. It was argued – by Professor Ndebele and others – that a plethora of other themes were part of the South African human experience and they also warranted exploration in literature. This Masters in Creative Writing work, which is comprised of a novel and a complementary reflexive essay (titled The Eyes of the Naked: What Do The Eyes of the Naked See?), explores the notion that, despite the end of apartheid, the conditions that gave rise to protest literature endure. There remains much to protest. There was plenty to protest before the advent of apartheid. Thus, in the essay, the novel The Eyes of the Naked is positioned in the South African canon between a seminal protest literature novel in Mongane Serote’s To Every Birth Its Blood and a pivotal post-apartheid literature text in Zakes Mda’s Ways of Dying. In all three novels there is a colonial thread that traverses epochs. It is suggested that The Eyes of the Naked is a reimagining of protest literature. However, this new variety unequivocally aspires towards complexity and depth. In the novel, protest is located in myriad themes that have their roots in the colonial (and apartheid) experience. These are themes such as civilian violence/crime; love; sexuality; filial disconnection; cultural deracination; masculinity/femininity; the migrant labour system; racism/xenophobia/revolution vs. terrorism. In the end, however, one must submit that The Eyes of the Naked is not classic protest literature. It is a revival of it that seeks to address, with creative depth and complexity, and through a host of other themes, the unrelenting subjugation of Africans in a land that is their home – on soil which most of their feet have never left.Item Drawing on Words: Jasper Johns's Illustrations of Samuel Beckett's Foirades/Fizzles(1994) Richards, Colin PeterBetween 1973 and 1976 artist Jasper Johns produced some thirty-three illustrations to accompany five prose texts authored by Samuel Beckett. The result was the book Foirades!Fizzles, published in New York in 1976. Almost without exception the critical literature published on this book draws the relation between image and text away from any idea of illustration. And this only when the idea is not simply ignored. This critical attitude reflects a wider tendency in especially elevated critico-aesthetic discourse to consider illustration as aesthetically and textually debased. Bracketed off, illustration merely signals a parasitic relation. Compromising the integrity of the texts it enjoins, it articulates a secondary aesthetic of the accessory. This view seems unproductive not only when applied to Johns's work, but also to image-text combinations more generally. The sheer incidence of such combinations (including illustration) in recent and current aesthetic production suggests that the indifference or prejudicial critical reflex routinely provoked by illustration marks a moment of poverty in contemporary critical thinking. This moment appears solidly rooted in a once dominant and still apparently powerful formalist and purist impulses within modernist discourse. The persistence of these impulses suggests the survival of unexamined, limiting and tenacious critical assumptions. A closer examination of selected texts - pre-modernist, modernist, and post-modernist - point beyond these assumptions. Here the logic of the supplement in particular illuminates very specifically how illustration might come to function, and where its incendiary critical potential may lie. The supplement resists the easy hierarchisation or even synthesis of different texts which has been the fate of illustration. It renders illustration both critically robust and radical. The concept of allegory is also illuminating here. It not only helps us understand better the fate of illustration within modernism and postmodernism, but also provides for enlightening readings of Foirades!Fizzles. In turn, a revaluation of illustration opens up a more productive view of allegory in both modernist and postmodernist discourse. Illustration, in coordinating different semiotic systems, however marginally, can function as a framing, focusing and spacing device, a way of bracketing and specifying themes, structures and forms within a given textual complex, a way of opening readings otherwise foreclosed or overlooked. In this study such readings are articulated through a set of textual configurations which include: vision and perception; the body, eye, and skin; calibration, measurement, and point of view; memory, repetition and originality; and finally liminality, ambiguity and metastable signification. Against the grain of published opinion there is then much to be gained by recognising the capacious critical potential of illustration, what we might term its 'motivated contingency'. Rather than being considered critically inconsequential or an aesthetic impedin1ent, illustration may in fact provide an almost unique opportunity not only to explore issues germane to Johns's work (both independently and in relation to Beckett's texts), but also to address certain important critical debates within postmodern discourse. Its value may be felt in reading Foirades!Fizzles, in reading other image-text combinations, and the broader relations between visual art, literature, and language.Item The geology of the Otjosondu manganese area: south west Africa(1959) Roper, HaroldGeological mapping and compilation of data from mining and prospecting operations in the Otjosondu area in South West Africa provided the information presented in this thesis. The geomorphology of the area is described and the general geology is discussed. Details of the complicated folding suffered by the Iamara rocks are presented. The petrology and petrography of' the outcropping representatives of the ancient sedimentary and intrusive rocks is described under the section on economic geology, interpretations of the complex structures of the ore bodies are presented. The mineralogy of the ores was studied by means of polished sections, X-ray diffraction and differential thermal analysis techniques. It is concluded from both field and laboratory evidence that these ores represent the metamorphosed equivalents of syngenetic manganese bearing sedimentsItem The Morphology and Transport of Mucus in Mammalian Airways.(1975) Andre William Wessels van AsThe mucociliary clearance mechanisms in mammalian pulmonary airways have been re-examined. In this investigation Wistar rats, housed both under specific pathogen free (SPF) and normal animal house conditions, were examined. An intact airway . system from the trachea down to the level of the terminal bronchioles was used. The airway preparation was rapidly isolated and examined under carefully controlled in vitro conditions. Specimens remained viable for at least 10 h. Mucociliary activity was observed through the intact bronchial wall with the aid of incident light. This function could be examined at all levels of the pulmonary tree in the same specimen. In contrast to the previously described presence of a continuous mucous bl~ket, the morphology of mucus in the airways of the rat has been shown to be discontinuous. Mucus is present as discrete particles of varying size. Under the light microscope these particles appeared to fall into three categories: droplets less than 4 μm in diameter; flakes 10-70 μm in diameter; and plaques which are conglomerations of droplets and flakes. Scanning electron microscopy reveals that droplets (i.e. single particles) may be as small as 0,5 μm and that composite particles made up of numerous aggregated droplets may be as small as 5 μm in diameter. Plaques are conglomerations of these particles. In the normal intrapulmonary airways only smaller particles are seen and are transported over the individual metachronal fields. In the larger extralobar airways these particles move together to be transported in well defined streams which may be up to 500 μm wide. These streams may follow a winding course up the trachea and more than one may be in operation at a time. Under conditions of hypersecretion such as occurs with chronic respiratory disease in rats (CRD) the number of particles increase peripherally and plaques may be found in small airways. The transport of mucus is however still intermittent and it never becomes confluent. Acute bronchitis results in wide-spread abnormalities of ciliary activity and mucus transport, which leads to total disorganisation of pulmonary clearance. "Chronic bronchitis" associated with CRD results in more organised abnormalities of mucociliary activity. Cilia may become inactive, reverse the .direction of their effective stroke, beat retrogradely, and exhibit abnormal beat patterns which result in impaired mucus clearance. Squamous metaplastic areas further impede mucus transport. In general mucus transport rates were found to be faster in rats with "chronic bronchitis" than SPF rats, provided that the extent of the damage to the mucous membrane was ( not too great in the "bronchitic" animal. This finding was confirmed by the examination of airway preparations approximately 19 h after the exposure to a charcoal aerosol. While significant amounts of charcoal were retained at the bifurcations of bronchi in SPF rats, most of the charcoal was cleared in "bronchitic rats'.'. The only areas where particles were seen were on bronchitic patches or on whirlpools. The findings of this study indicated that mucus was present in a discontinuous form, and that in both SPF and non-SPF animals no evidence for a mucous blanket was found.Item The Morphology and Transport of Mucus in Mammalian Airways.(1975) Andre William Wessels van AsThe mucociliary clearance mechanisms in mammalian pulmonary airways have been re-examined. In this investigation Wistar rats, housed both under specific pathogen system frfroeme (tShPeFt)raacnhdeanodrmowanl taonimthael lheovuelseofcotnhdeititoenrms, inwael rbe roexnacmhiionleeds . wAans uinsetadc. t airway The airway preparation was rapidly isolated and examined under carefully controlled in vitro conditions. Specimens remained viable for at least 10 h. Mucociliary activity was observed through the intact bronchial wall with the aid of incident light. This function could be examined at all levels of the pulmonary tree in the same specimen. In contrast to the previously described presence of a continuous mucous bl�ket, the morphology of mucus in the airways of the rat has been shown to be discontinuous. Mucus is present as discrete particles of varying size. Under the light microscope these particles appeared to fall into three categories: droplets less than 4 µm in diameter; flakes 10-70 µm in diameter; and plaques which are conglomerations of droplets and flakes. Scanning electron microscopy reveals that droplets (i.e. single particles) may be as small as 0,5 µm and that composite particles made up of numerous aggregated droplets may be as small as 5 µm in diameter. Plaques are conglomerations of these particles. In the normal intrapulmonary airways only smaller particles are seen and are transported over the individual metachronal fields. In the larger extralobar airways these particles move together to be transported in well defined streams which may be up to 500 µm wide. These streams may follow a winding course up the trachea and more than one may be in operation at a time. Under conditions of hypersecretion such as occurs with chronic respiratory disease in rats (CRD) the number of particles increase peripherally and plaques may be found in small airways. The transport of mucus is however still intermittent and it never be comes confluent. Acute bronchitis results in wide-spread abnormalities of ciliary activity and mucus transport, which leads to total disorganisation of pulmonary clearance. "Chronic bronchitis" associated with CRD results in more organised abnormalities of mucociliary activity. Cilia may become inactive, reverse the .direction of their effective stroke, beat retrogradely, and exhibit abnormal beat patterns which result in impaired mucus clearance. Squamous metaplastic areas further impede mucus transport. In general mucus transport rates were found to be faster in rats with "chronic bronchitis" than SPF rats, provided that the extent of the damage to the mucous membrane was not too great in the "bronchitic" animal. This finding was confirmed by the examination of airway preparations approximately 19 h after the exposure to a charcoal aerosol. While significant amounts of charcoal were retained at the bifurca tions of bronchi in SPF rats, most of the charcoal was cleared in "bronchitic rats .The only areas where particles were seen were on bronchitic patches or on whirlpools. The findings of this study indicated that mucus was present in a discontinuous form, and that in both SPF and non-SPF animals no evidence for a mucous blanket was found.Item The penetration and fracturing mechanisms generated in brittle rock by the impingement of a high velocity jet(1992) Giltner, Scott GeorgeExtensive studies on the jet penetration process in ductile metal targets have been previously carried out in numerous investigations. As a result, the penetration in ductile targets has been characterized by various theoretical models. However the penetration of brittle materials, particularly rock, has received considerably less attention. The lack of information concerning brittle materials is important as major differences between penetration in ductile and brittle materials have been observed. In most instances the actual penetration in brittle materials is far less than that given by theoretical calculations. This thesis presents an investigation into the high velocity jet penetration of brittle rock. The aim of this work is to describe the dynamic forces transmitted into the rock by the jet and the subsequent response of the rock to these forces. It is shown that existing penetration theories do not adequately describe penetration in rock. Of all the jet and target properties considered in the theories examined, target strength is shown to be the most relevant for predicting penetration depth. Recovery of the actual hole created was achieved by overcoring of the hole. Detailed measurements of the hole profile and fracture zones around the hole are presented. From the recovered samples of the hole, thin and polished sections were obtained for microscopic analysis. Results from the microscopic examination of these specimens are discussed from which temperature and pressure information are derived. In order to provide an adequate description of the penetration process, instrumentation was used to measure the penetration velocity, particle acceleration, and dynamic strain generated in the rock. From the instrumentation the interface pressure, dynamic stress, and dynamic strain generated in the rock are quantified and related to the various fracture zones identified around the hole. The results of these tests indicate that penetration in rock can be separated into three distinct phases. Initially the rock behaves as a hydrodynamic fluid should the interface pressure be very high. However as the interface pressure drops, the strength of the rock becomes evident and the second phase is entered into. The second phase is characterized by rapid changes occurring in the behaviour of the rock. Once the behaviour of the rock has stabilized, the third and final phase of penetration is entered. This final phase is predominantly controlled by the rock strength. As a result of this investigation, a better understanding of the interaction between the rock target and penetrating jet has been established. Additionally the behaviour of rock subjected to very high shock pressure has also been described. This has allowed better insight into the material properties governing the penetration process and the fracturing of rock from purely dynamic stresses.Item Item Experiences of unemployment, the meaning of wage work: the dilemma of wage work among ex-gold mineworkers in the Free State Goldfields(2018) Sefalafala, Thabang MasiloThe thesis explores experiences of unemployment to understand the meaning of wage work. This ethnographic research focuses on the everyday lived experiences of unemployed ex-mineworkers in their local contexts. Through personal narratives of men laid off from the dying Goldfields of the Free State (previously called the Orange Free State (OFS), it aims to explicate the powerful moral effects of wage work in a context of pervasive joblessness. Ex-mineworkers affirmed their commitment to wage work as the only way in which security, respect, pride, and dignity can happen in society. Yet, increasingly, in South Africa and indeed across the world, wage work can no longer fulfil those values and its traditional promise. The findings illuminate how unemployment had a profound impact on ex-mineworkers’ sense of self and their place in their homes and communities. They suffer stigma, diminished sense of masculine confidence and negative self-perceptions. The thesis describes the ways in which unemployment was experienced as economic insecurity, social insecurity, and psychological distress. However, I argue that these impairments are only symptoms of a much deeper problem, that is, they experienced a deep moral unease at being unemployed. These impairments do not produce deleterious effects on the unemployed merely because they cause poverty, social uncertainties, and psychological distress, which of course are important, but because a particular moral regulation has lost hold over individuals. The thesis argues that unemployment produced deleterious effects on the unemployed because it occasioned the abrupt disruption of, and loss of shared collective moral values without the immediate provision of an alternative collective moral order in place of the old. As such, unemployment is experienced as loss. Ex-mineworkers attempted to overcome the three impairments through a combination of livelihood strategies. Strategies included standing by the side of the road (men by the side of the road), collecting scrap metal for recycling and remittances. They often inadequately benefitted (indirectly) from various state grants. The livelihood activities they undertook were seen as humiliating and driven by desperation and they were unable to facilitate and secure sustainable and predictable sources of economic security or new forms of social status and dignity. With the above in mind, ex-mineworkers imagined the positive impact that a Basic Income Grant (BIG) or an unemployment grant would have in reducing the insecurities (economic, social, and psychological) of the unemployed. They framed grants as ‘handouts’ which while reducing insecurities, cannot, ultimately, substitute wage work and the values tied to it. They preferred employment and jobs over non-wage forms of income distribution. But this raises a policy dilemma; What happens when full employment becomes impossible? If job creation fails, how do we explain the continued commitment to wage work as the central medium of what it means to live a productive life? I argue, the answer lies not only with respect to the economic benefits tied to jobs, but rather, a deeper historical sociological factor, which is the moral status of wage work in society. The moral status and commitment to wage work, not only makes wage work the only perceived viable way of attaining livelihoods, a meaningful life, masculine status etc., but it also hegemonically blinds the unemployed, policy makers and analysts to imagine possibilities of decent life outside wage work.Item Laser shock peening in friction stir welded joints with lack of penetration defects(2016) Leering, Mitchell PatrickThis experimental work was conducted in order to assess the influence of the application of Laser Shock Peening (LSP) to Friction Stir Welded (FSW) joints. LSP has the ability to potentially recover the reduction in joint mechanical properties that arose due to the presence of a common FSW defect known as Lack of Penetration (LOP). The material used throughout this study was 3 mm thick AA6082-T6 Aluminium. This specific material was selected due to its weldability and common use in the manufacturing of aircraft structures. A 20 mm diameter, spiralled profile shoulder and 5 mm diameter, tapered, three facetted pin was used in the manufacturing of the FSW joints. Experimental assessment and optimisation of the FSW parameters window consisted of the varying the tool rotational speed from 630 to 1600 RPM, at five increments and the feed rate from 200 to 600 mm/min, 200 mm/min intervals. The joints were assessed on the overall quality, microstructure, ductility and static strength. The parameter combinations produced joints with ultimate tensile joint efficiencies which ranged from 48% to 74% that of the base material. The initial study showed that higher welding rates, typically associated with low feed rates, resulted in the highest quality joints. This was attributed to the sufficient thermal softening of the material during welding. The increased welding temperatures improved the joint formation, material flow and mechanical properties. Due to the elevated welding temperatures and material flow, substantial flash formation was observed on all joints manufactured with a welding rate of 5 rev/mm and higher. These results formed the foundation of the multi-objective optimisation in order to determine the most suitable parameters for this welding configuration. The optimisation simulation determined the optimum parameters to be, a tool rotational speed of 1433 RPM, feed rate of 196 mm/min and a welding rate of 7.3 rev/mm. Due to the fixed gearing of the CNC FSW machine the required tool rotational speed could not be achieved, thus, all FSW completed after the optimisation was completed at 1600 RPM, 200 mm/min and 8.00 rev/mm. This parameter combination produced a joint of high structural integrity, high ductility and with no visual sign of internal voids, defects or lack of penetration. The performance of the defect free joint formed the foundation of the characterisation of the influence of intentionally introduced LOP defects. LOP was defined as a pre-initiated crack which formed at the root surface during the fabrication of a FSW joint. Controlled and consistent LOP was introduced into the joints, manufactured with welding parameters of 1600 RPM and 200 mm/min, by offsetting the welding tool in combinations of the normal and lateral directions relative to the joint line. The defects originated at the root surface and extended at various lengths through the thickness of the joints due to the numerous offsets. The defects lengths ranged from a few microns to as much as 954.5 μm. A number of defects affected as much as 43% of the joint thickness. The presence of the defects negatively affected the joints structural static strength by as much as 9% to 27% (dependent on the size of the defect) and dynamic fatigue life of as much as 36%. Laser Shock Peening (LSP) is a novel post manufacturing technique, which has been used to introduce compressive residual stresses within the near surface of the metallic components. A LSP processing was completed without a protective ablative coating (LSPwC), at a wavelength of 1064 nm and pulsed nano-second laser at 10 Hz. The characterisation of varying the laser power intensity and processed coverage to the base of FSW AA6082-T6 Aluminium was completed through extensive parameter window exploration. Factors such as the quality of the energy delivery, sample deflection, strain hardening, penetration of effects through the FSW joint thickness and the improvement of the fatigue life of the base material were used to define the appropriate parameters. A multi-objective optimisation strategy was implemented in the attempt to fully explore the regions between tested parameter combinations; to provide an optimum set of LSP parameters which would be used in combination of the optimum FSW parameters. The simulation predicted two optimum sets of parameters dependent on the desired outcome of either maximising component fatigue or LSP depth of penetration effect. Due to the nature of this research requiring both fatigue and penetration depth, a parameter set was selected based on parameters that would theoretically provide the maximum for both desired outcomes. The optimum power intensity and coverage was specified as 3.33 GW/cm2 and 1067 spots/cm2. The optimum parameters of each process was combined in an attempt to recover the drop in fatigue life of the joints due to the presence of the LOP defect. LSP was capable of altering the near surface residual stress states of approximately 100 MPa tensile to -150 to -200 MPa compressive across the three measurement ranges. It was found that LSP had minimal effect on the fatigue life of the components in the low cycle fatigue due to the applied stress relaxing the introduced stress thus having minimal effect on the life of the joints. LSP was found to increase the fatigue life of the non-defective joints by as much as 68%. LSP showed a life improvement of approximately 20% in a joint which had a defect length of roughly 175μm. After the application of LSP the samples in the low cycle fatigue tended to fail at a closed cycles to failure as the non-defective unpeened samples. Application of a LSP to a FSW was found to shift the fracture position of the flawed components from the region of the defect to that of the Heat Affected Zone (HAZ) on the advancing side of the weld. It is suggested that, the shift in fracture position was due to critical relocation of the tensile stress during LSP into the HAZ on the advancing side. The results did not conclusively show that LSP was capable of recovering the effects of the LOP but was plausible that it could possible. This has been said due to some samples exhibiting an increase and due to the change in location of the fracture position.