This project documents my process of visual and hermeneutic enquiry centred on the Tswaing meteorite impact crater, north of Pretoria. In my visual investigation I attempt to apprehend the landscape through a cyclical process which involves walking within it, photographing it in 360° ‘visualisations’, editing the imagery and returning, often frustrated, to repeat both encounter and process. The cycle of reflection leads me to consider my circular process itself as a dialogical mode of interpretation and response to the primeval, circular landscape of the impact crater. Informed by Gadamer’s (1975) notion of a hermeneutic circle which extends interpretation and understanding, the reflexive process is extended and enriched through dialogue with the work of pertinent scientists, artists, poets and writers. Landscape is considered as an artefact of deep time, challenging entrenched traditions and notions while considering significant contemporary responses. The dissertation attempts to demonstrate the layered accretion of concept and meaning contained within the visual and theoretical components of the investigation

The Vredefort Dome is located southwest of Johannesburg, South Africa, and represents the deeply eroded remnant of the central uplift of the world’s largest known impact structure, with an estimated diameter of ~300 km. The Vredefort impact structure is also the oldest known impact structure on Earth (~2.02 Ga). The Vredefort Dome comprises an ~40 km wide core of Archaean basement gneisses and an ~20 km wide collar of subvertical to overturned Late Archaean to Palaeoproterozoic supracrustal strata. This project presents the results of Landsat-TM and aerial photograph analysis, as well as field mapping of Witwatersrand Supergroup metasedimentary strata in the collar of the Vredefort Dome. The aim of this study was to investigate the structures (such as folds, faults, fractures), at all scales, and other deformation features (such as shatter cones and pseudotachylitic breccias) in the field area, and to establish geometric and temporal relationships between these features with regard to the impact cratering process. This study revealed a highly heterogeneous internal structure of the collar involving folds, faults, fractures and melt breccias that are interpreted as the product of shock deformation and central uplift formation during the Vredefort impact event. Broadly radially-oriented symmetric and asymmetric folds, with wavelengths from tens of metres to kilometres, and conjugate radial to oblique faults with strike-slip displacements of, typically, tens to hundreds of metres accommodated tangential shortening of the collar of the dome that decreased from ~17 %, at a radial distance from the dome centre of 21 km, to <5 % at a radial distance of 29 km. Ubiquitous shear fractures containing pseudotachylitic breccia, particularly in the metapelitic units, display variable local slip senses consistent with either tangential shortening or tangential extension; however, it is uncertain whether they formed at the same time as the larger faults during the rise of the central uplift or earlier, during the shock compression phase of cratering. Contrary to the findings about shatter cones of some earlier workers in the Vredefort structure, the Vredefort cone fractures do not show uniform apex orientations at any given outcrop, nor do small cones show a pattern consistent with the previously postulated “master cone” concept. The model of simple back-rotation of the strata to a horizontal pre-impact position also does not lead to a uniform centripetal-upward orientation of the cone apices. Striation patterns on the cone surfaces are variable, ranging from typically diverging, i.e., branching off the cone apex, to subparallel to parallel on almost flat surfaces. Striation angles on shatter cones do not increase with distance from the crater centre, as suggested previously. Instead, individual outcrops present a range of such striation angles, and a more irregular distribution of striation angle values with regard to the distance from the crater centre suggests localised controls involving the nature and shape of various heterogeneities in the target rock on this aspect of cone morphology. On the basis of the observations made during this study on small-scale structures in the collar of the Vredefort Dome, the relationship of shatter cones with curviplanar fractures (multipli-striated joint sets - MSJS) is confirmed. Pervasive, metre-scale tensile fractures crosscut shatter cones and appear to have formed after the closely-spaced MSJ-type fractures. The results of this study indicate that none of the existing models is able to explain all characteristics of shatter cones fully; therefore, a combination of aspects of the different models may currently be the best possible way to explain the formation and origin of shatter cones, and the formation of the related MSJ and their characteristic aspects (e.g., curviplanar shape, melt formation, etc.). The observed variety of shatter cone orientations, surface morphology and striation geometry in the dome concurs broadly with the results of some previous studies. The abundance of striated surfaces along closely-spaced sets of fractures (MSJ) observed in this study can be reconciled with reflection/scattering of a fast propagating wave at heterogeneities in the target rocks, as proposed by recent studies. This would mean that closely-spaced fractures and shatter cones were not formed during shock compression, as widely postulated in the past, but immediately after the passage of the shock wave, by the interference of the scattered elastic wave and the tensional hoop stress that develops behind the shock front. In addition to shatter cones, quartzite units show two other fracture types – a centimetre-spaced rhomboidal to orthogonal type that may be the product of shock-induced deformation and related to the formation of shatter cones, and later joints accomplishing tangential and radial extension. The occurrence of pseudotachylitic breccia within some of these later joints confirms the general impact timing of these features. Pseudotachylitic breccias in the collar rocks occur as up to several centimetre-wide veins with variable orientations to the bedding and as more voluminous pods and networks in zones of structural complexity, such as the hinges of large-scale folds and along large-scale faults, as well as locally, at lithological interfaces. In places, tension gash arrays along thin veins are observed indicating that movement occurred along these planes. Initial cooling calculations for pseudotachylitic breccias of different widths and compositions (metapelite or quartzite) suggest that thick veins (<10 cm) could have stayed molten over the entire duration of crater development (at least 10 minutes), making it possible for shock-induced melts to intrude dilational sites, such as fold hinges and extensional fractures, during the formation and subsequent collapse of the central uplift. Intrusion of such melts may also have lubricated movements along brittle and ductile structures. Thus, the presence of both shock- and friction-generated melts is likely in the collar of the Vredefort Dome. Based on the spatial and geometric relationship between the structures and other deformation features observed in the collar rocks of the Vredefort Dome, it is possible to establish a temporal sequence of deformation events. Shatter cones and related closely-spaced fractures were formed during the contact/compression phase of the cratering process. The formation of at least some shock-induced pseudotachylitic breccia also belongs into this phase. Large-scale folds and faults and friction-generated melts can be related to the initial formation of the central uplift and extensional joints to the subsequent collapse of the central uplift.

Introduction: Nontyphoidal Salmonella (NTS) has been associated with HIV from the outset of the HIV pandemic. The few NTS studies done in Africa and America have not documented the impact of HIV on clinical-microbiologic features and mortality in patients with NTS infection. This study determined the association between HIV serostatus and mortality proportion, clinical presentation, length of hospital stay, frequency of invasive NTS infection recurrence, NTS serotypes and estimated the population attributable fraction of mortality due to HIV among patients with invasive NTS infection in South Africa. Methods: Secondary data from enteric diseases national surveillance in South Africa from 2003 to 2006 were analysed as a cross sectional study. A total of 1 398 subjects with known HIV serostatus were obtained after data cleaning. Data analysis was done in Stata using chi squared test for categorical variables and Wilcoxon rank sum test / Kruskal- Wallis test for continuous variables. Logistic regression models were used to quantify the associations, and adjust for confounders and effect modification. Population attributable fraction was calculated to quantify the impact of HIV on mortality. Results: Majority (82.26%) of patients were HIV positive. The frequency pattern of HIV positive serostatus in different age groups coincided with that of invasive NTS. The overall mortality was 32.00%. HIV positive patients had a higher proportion (35.79 %) of mortality than HIV negative patients (15.55 %) (P<0.001). Fifty five percent of deaths in this study population were attributed to HIV infection. In multivariate models, HIV positive patients were more likely than HIV negative patients to die (OR = 2.50, 95% CI 1.69- 3.70), to develop lower respiratory tract infection (LRTI) (OR = 1.89, 95% CI,1.34- 2.65), to have recurrence of invasive NTS (OR = 3.90, 95% CI 1.41-10.77), to stay less than 16 days in hospitals (OR = 1.61, 95% CI, 1.08-2.40) and to be infected with Salmonella serotype Typhimurium infection (OR = 2.59, 95% CI 1.91-3.51). There were no significant differences in temperature, cardiac arrest, meningitis and site of specimen isolation (p>0.05). Discussion: The major limitation to this study was poor data quality of the surveillance system, including missing HIV serostatus hence the findings cannot be generalized to patients with unknown HIV status. Conclusion: HIV infection is common among patients with invasive NTS and is associated with excess mortality, LRTI, fewer than 16 days of hospital stay, recurrent invasive NTS infection and Salmonella Typhimurium. It is important for clinicians to rule out HIV infection in patients with invasive NTS especially those presenting with LRTI and Salmonella Typhimurium infection in addition to recurrent NTS infection, which is a wellknown feature associated with HIV. Recommendation: Since these patients received antimicrobials and had considerable mortality, the first line treatment of invasive NTS should be reviewed especially to HIV positive patients by investigating resistance patterns and conducting a clinical trial of newer and effective antimicrobials.

A research report submitted to the Faculty of Science, University of the Witwatersrand, in partial fulfilment of the requirements of the degree of Master of Science. Johannesburg, 2016. / This study evaluates the Environmental Impact Assessment (EIA) practice in the South African energy sector against a criteria developed by the researcher to determine the extent to which the EIAs contribute towards sustainable development. A questionnaire survey was conducted to gather information on the performance of the EIA practice of Eskom, which in this study represents the energy sector of South Africa. A review of the quality of a sample of EISs was also done against the modified Lee and Colley review package. The study revealed some strengths and weaknesses of EIA, as practiced by Eskom. The strengths include effective mitigation, public participation, training and the use of resources within ecological limits. The EISs were found to be generally of satisfactory quality. The weaknesses which limit EIA in the energy sector to reach its full potential in promoting sustainable development include inadequate monitoring, inadequate consideration of cumulative impacts and alternatives and inadequate engagement with community members directly affected by development projects on a personal level. Despite these weaknesses, the study concludes that EIA in the energy sector contributes, to some extent, towards the promotion of sustainable development. Key words: Environmental Impact Assessment, EIS, sustainable development, monitoring, mitigation, public participation, alternatives, ecological limits / LG2017

Thesis (M.Sc.)--University of the Witwatersrand, Faculty of Science, School of Environmental Sciences, 2017. / Public participation in environmental impact assessments has been the subject of many studies around the world. The effectiveness of the public participation process in a South African context has however not been tackled by many authours. A study was conducted in order to assess the effectiveness of the public participation for environmental impact assessments in South Africa. In order to achieve this, 20 environmental impact reports were scrutinised, key informant interviews were conducted and analysis of legislation, regulation as well as applicable Guidelines was carried out. Results indicated that public participation in environmental impact assessment regulation fall short of addressing what the principles of the law states. Consequently, there is a need for the review of regulation to prescribe the involvement of marginalised groups through additional participation such as public meetings in the appropriate language as well as ensuring skills development to aid in effective participation. The inclusion of the monitoring of the implementation of the environmental management programmes as well as the inclusion of public participation in this process and therefore the life cycle of the project will aid in ensuring that the public has access to decision making. / XL2018

Cette thèse est réalisée au sein du Laboratoire de Génie Industriel et Production de Metz (LGIPM) et s'inscrit donc dans une dynamique à la fois européenne et mondiale qui est la réduction des impacts environnementaux et sociétaux des systèmes de transport. Notre but est de développer un système d'aide à la décision au choix d'un itinéraire de fret ayant le moins d'impacts possible sur l'environnement et la société. Pour se faire, nous avons défini des fonctions qui permettent de calculer pour chaque chemin d'un réseau de transport intermodal, les critères économiques (coût, temps, dégâts dus aux transbordements) et les critères écologiques (pollution, consommation d'énergie, nuisances sonores et risque d'accident) à considérer. Par la suite, nous avons construit un modèle de plus court chemin multiobjectif permettant d’optimiser les sept critères ainsi définis. Pour résoudre ce modèle, un algorithme de colonies de fourmis multiobjectif a été mis en place afin de prendre en compte le grand nombre de critères et l'intermodalité du réseau. Une implémentation est ensuite réalisée sur un réseau de transport intermodal se basant sur des données géographiques réelles et les performances de l’algorithme mis en place sont analysées et prouvées / The topic of this thesis is about environmental and societal impacts abatement within the green supply chain. This thesis is taking place in the Laboratory of Industrial Engineering and Production of Metz (LGIPM). Our goal is to develop a decision support system in choosing a path with the less environmental and societal impacts. For building our decision support system, we defined a mathematical model which computes for each part in our transportation network, the travel time, the transportation cost and the damage due to transshipment, the amount of greenhouse gas emissions that are emitted, the energy consumption, the noise emitted and the accident risk. From this graph, we built a multiobjective shortest path problem. A multiobjective ant colony algorithm MOSPACO (Ant colony optimization for multiobjective shortest path problem) is then proposed to solve the proposed multiobjective shortest path problem; this new algorithm aims to take into account the large number of criteria and intermodal network. The running of the algorithm gives a Pareto front from which the decision maker can choose his desired itinerary

Ice hockey helmets effectively mitigate the risk of skull fractures and focal traumatic brain injuries in professional ice hockey (PIH), but do not manage diffuse brain injuries such as concussion. This is due to current standard tests, which only represent one head impact event (a fall to the ice) and do not measure rotational head kinematics. It is important that helmets are evaluated using impact conditions that represent how players sustain concussions in ice hockey. The objective of this study was to describe the relationship between three ice hockey helmet tests and reconstructions of three concussive injury events in PIH. A flat anvil drop test (representing head-to-ice impacts), angled anvil drop test (representing head-to-boards impacts at 30o and 45o) and pneumatic ram test (representing medium and high compliance shoulder-to-head impacts) were performed using parameters reflecting concussive injuries in PIH. Stepwise regressions identified the dynamic response variables producing the strongest relationships with MPS. For the flat anvil drop test, dominant linear acceleration had the strongest relationship with MPS (R2 = 0.960), while there were no significant predictors of MPS from the PIH head-to-ice reconstructions. Rotational velocity had the strongest relationship for the 30o (R2 = 0.978) and 45o Anvil Drop Tests (R2 = 0.977), while rotational acceleration had the strongest relationship for the PIH head-to-boards reconstructions (R2 = 0.649). Resultant rotational acceleration had the strongest relationship for the medium compliance ram test (R2 = 0.671), the high compliance ram test (R2 = 0.850) and the PIH shoulder-to-head reconstructions (R2 = 0.763). The flat anvil drop test results indicate that falls on a flat, rigid surface induce primarily linear acceleration of the head. Standards should continue using this type of test to ensure helmets prevent skull fracture and focal TBI. Ice hockey helmets should also be evaluated using an angled anvil drop test and a collision ram test, representing two unique head impact events known to cause concussive injuries. The 45o Anvil Drop Test provided a closer representation of concussive head-to-boards impacts in PIH, with rotational velocity producing the strongest relationship with MPS. For collision impacts, the Medium Compliance Ram Test yielded repeatable impact conditions while the High Compliance Ram Test provided a closer representation of real-world concussive shoulder-to-head impacts. For these pneumatic ram tests, rotational acceleration produced the strongest relationship with MPS. The information in this thesis may be used by standards organizations when designing future ice hockey helmet tests.

液滴撞在固體上是個常見現象並且有廣泛的應用，譬如噴墨打印，塗層，工業冷卻以及飛機上的積冰。當液滴撞在乾燥的表面上會出现很多的結果：它可能完全反彈，或平緩的展開，或猛烈地飛濺出許多微小的液滴。影響撞擊過程包括撞擊速度，液體和固體的性質以及周圍的空氣。最近的研究發現降低周圍氣體壓強可以抑制液體飛濺。這表明空氣對於飛濺機制起了關鍵作用。因此，了解在液固撞擊過程中空氣的重要性會給這一基本現象帶來新的發展，並可能改善如控制飛濺和表面塗層等一些實踐過程。 / 採用高速攝影和顯微成像技術，我們做了液滴撞擊光滑且乾燥固體表面的實驗，研究了被困在裡面的氣體。我們觀察了在液體接觸襯底之前一層氣膜被壓縮並形成的過程，發現其壓強比大氣壓值要高得多。壓縮程度取決於撞擊速度，我們通過減速的液體與壓縮空氣的平衡關係給出了解釋。在液體與襯底接觸後，空氣膜的邊緣在豎直方向上擴展，壓強在幾十微秒內迅速降低。這個厚的邊沿在表面張力，慣性力和粘性阻力的複雜相互作用下最終收縮成氣泡。 / 當液滴以很高的速度撞擊平滑固體表面上，液體發生飛濺。人們對這個常見的現象缺乏基本的了解。採用高速攝影技術，我們觀察到是被困在展開液體前沿下的超薄氣膜觸發了飛濺現象。因為這層薄膜比空氣分子的平均自由程更薄，具有與聲速相當的非常高速來轉移動量，並產生一個比常規計算強十倍的應力。如此"強風"在小尺度上開起了開爾文-亥姆霍茲不穩定性並且有效地產生飛濺。我們的模型定量地與實驗驗證相符，並給出了一個對於液滴在光滑表面上飛濺的基本解釋。 / The impacts of liquid drops onto solid substrates are ubiquitous and appear in a variety of applications, such as ink-jet printing, spray coating, industrial cooling processes and ice accumulation on aircraft. When a liquid drop hits a dry substrate, there are many possible outcomes: it can rebound completely, spread smoothly, or splash dramatically ejecting many tiny daughter droplets. Clearly, the hitting dynamics may be influenced by different factors, including the velocity of impact, liquid and surface properties, as well as the surrounding air. Recent study reveals that by lowering the ambient gas pressure, liquid splash could be eliminated. It indicates that the role of air is a significant key to the mechanism of splash creation. Therefore, understanding the behavior of air during liquid-solid impacts will bring new advances to this fundamental phenomenon, and may benefit practical processes such as splash control and surface coating. / Using high-speed photography coupled with optical interference, we experimentally study the air entrapment during a liquid drop impacting a smooth and dry solid substrate. We observe the formation of a compressed air film before the liquid touches the substrate, with internal pressure considerably higher than the atmospheric value. The degree of compression highly depends on the impact velocity, as explained by balancing the liquid deceleration with the large pressure of the compressed air. After contact, the air film expands vertically at the edge, reducing its pressure within a few tens of microseconds and producing a thick rim on the perimeter. This thick-rimmed air film subsequently contracts into an air bubble, governed by the complex interaction between surface tension, inertia and viscous drag. Such a process is universally observed for impacts above a few centimeters high. / When a fast-moving drop impacts onto a smooth substrate, splashing will be produced at the edge of the expanding liquid sheet. This ubiquitous phenomenon lacks a fundamental understanding. With high speed photography, we illustrate that an ultra-thin air film trapped at the expanding liquid front triggers splashing. Because this film is thinner than the mean free path of air molecules, the interior air flow transfers momentum with an unusually high velocity comparable to the speed of sound, and generates a stress ten times stronger than the conventional calculation. Such a "strong wind" initiates Kelvin-Helmholtz instabilities at small length scales and effectively produces splashing. Our model agrees quantitatively with experimental verifications, and brings a fundamental understanding to the ubiquitous phenomenon of drop splashing on smooth substrates. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Liu, Yuan = 液體固體碰撞過程中空氣重要性的研究 / 劉嫄. / Thesis (Ph.D.) Chinese University of Hong Kong, 2014. / Includes bibliographical references (leaves 78-80). / Abstracts also in Chinese. / Liu, Yuan = Ye ti gu ti peng zhuang guo cheng zhong kong qi zhong yao xing de yan jiu / Liu Yuan.

Bioplastics are emerging as most promising materials to replace oil based thermoplastics particularly in packaging. Bioplastics can mitigate and address concerns about the negative role of plastics in the environment creating pollution and depleting resources hence bioplastics can enable an innovative approach toward addressing these issues. However, manufacturing of bioplastic is still costly and their mechanical and thermal properties require extensive development. Therefore there has been substantial interest to improve processing and properties of bioplastics to diminish the environmental impacts caused by continuous use of synthetic polymers of petroleum origin. In this research, Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) or PHBV and Polybutylene succinate (PBS) composites and blends were developed to improve the properties of PHBV as the matrix polymer and hence produce a novel formulation for product development. Three approaches were studied in this work:  The effect of talcum powder as a nucleating agent and reinforcing filler.  The effect of oligomer chain extenders on miscibility, crystallinity, thermal and thermomechanical, mechanical and morphological properties of PHBV/PBS blends.  The effect of acrylic core-shell impact modifier on crystallinity, thermal and thermomechanical, mechanical and morphological properties of PHBV were also evaluated. All the above scientific approaches have been studied. It was noticed that talc can change the sluggish crystallinity of PHBV. Talc enhances nucleation of PHBV in the composites which leads to a faster crystallization rate. The heat distortion temperature, crystallinity and the modulus of PHBV/talc composite were also increased. In the presence of the chain extender (CE) the miscibility conditions of PHBV/PBS blends were changed. The results were supported by calculation of the activation energies. The elongation at break and tensile strength of PHBV/PBS/Chain extender blends increased indicating miscibility change. The possible reaction mechanism between PHBV, PBS and CE are proposed and the results supported by using FTIR. Immiscibility results of the PHBV/PBS blends are supported by SEM images. Addition of the impact modifier to PHBV reduced the crystallization rate and prolonged crystallization time. It has been found that the shell of impact modifier (PMMA) is partially miscible with PHBV. The absorbed impact energy is improved by the impact modifier but the improvement was not as satisfactory as results noted for PLA. The SEM images showed the average fine dispersion of different sized particles inside the matrix.

The status of ‘Shakespeare’ is an incredibly intricate cultural construct, which is influenced by circumstantially contingent hierarchies of value, academic discourses, institutional processes, educational curricula, and media techniques. Having explored the context in which Shakespeare currently stands as an icon through the review of existing scholarship, this thesis employs a combined methodology to facilitate an investigation of some of the ways in which the playwright and his works are significant in contemporary culture, by specifically examining three late-1990s Shakespearean films and some particular types of audience responses. The case studies – Romeo + Juliet, Shakespeare in Love and 10 Things I Hate About You – are each analysed, according to their individual content and context, as cinematic products, which are understood in relation to Shakespeare and also many other cultural frameworks. It is acknowledged that Shakespeare has a particularly potent and established iconicity within academia and the education system, and it is argued that this position informs, but is also modified and challenged by, the filmic conceptualisations. These observations are enriched and developed by the findings of empirical audience research. Questionnaires were used to elicit a mixture of quantitative and qualitative information from secondary school teachers of Shakespeare, and from first year English and/or media undergraduates, about their experiences and opinions of Shakespeare in contemporary culture, especially Shakespearean films. Patterns identifiable in the data generated confirm that cinematic interpretations can transform the cultural currency of Shakespeare, reducing the distance between young people and the text by using familiar modes of address, but also point to tensions stemming from a disjunction of conventional evaluative criteria and the diverse ways in which Shakespeare now functions in mass culture. This work therefore contributes to debates about Shakespeare’s cultural status by examining the complex processes of negotiation of meaning that are discernable in these instances.