ROLE OF ETA PHASE EVOLUTION ON CREEP PROPERTIES OF NICKEL BASE SUPERALLOYS USED IN ADVANCED ELECTRIC POWER GENERATION PLANTS

Advanced fossil energy power generation plants require materials that withstand high temperatures and corrosive environments. One such material that is used in steam turbines is Nimonic 263. It is a nickel-base superalloy that is principally strengthened by gamma primephase (Ni3(Ti, Al)) and has an L12structure. At extended times and at turbine operating temperatures however, eta (Ni3Ti) phase is known to form at the expense of gamma prime. Eta has a complex DO24structure and is the stable phase between 750°C and 900°C, but with slow kinetics of formation. Little is understood about eta phase, and it may negatively impact the strength and creep resistance of Nimonic 263. The hypothesis of this project is that eta phase lowers the steady state creep rate of Nimonic 263. The aim of this project was to study the creep performance and deformation behavior of three related materials to isolate the effects of eta phase on steady state creep behavior in secondary creep regime. The three materials are: Standard commercial Nimonic 263 containing only gamma prime Standard commercial Nimonic 263 that has been heat-treated to contain both gamma primeand eta phases prior to creep testing Modified Michigan Tech alloy based on Nimonic 263 that contains only eta and no gamma prime Based on this improved understanding of creep deformation and failure mechanisms as a function of eta phase, existing creep models were modified to reflect eta phase effects in secondary creep. This modified model will improve life prediction and component design for advanced fossil energy power plant systems

Exploring the role of the local state in the production and maintenance of space through the delivery of basic services and community responses: the case of N12 highway park, Ekurhuleni metropolitan municipality

A Dissertation submitted to the Faculty of Engineering and Built Environment, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of Master of Urban Studies. Johannesburg, 2018.This dissertation rests on the argument that spatial production in informal settlements is shaped by state planning processes and the practice of service delivery. The South African urban landscape has been characterized by increasing amounts of informal settlements and the continuities of harsh state responses to these settlements in the form of evictions and relocations. There is a large body of literature on the spatial consequences of informal settlements which is usually centred on poor people-state relations and elaborated through two dynamics. Firstly, the retaliation of residents of informal communities towards the state in the form of Holston’s (1998) insurgent citizenship and protests. Secondly, looking at state responses to informality through policy and clientalist relations, this limiting the attention to the personal experiences of residents living in informality. This ethnographic study explores the theoretical concepts of spatial production and meaning of place for people living in informality. It builds on the work of Henri Lefebvre and Yi Fu Tuan who attribute value to everyday practices and experiences in producing space. These concepts are employed to investigate how the community of N12 Highway Park in the Ekurhuleni Metropolitan Municipality has produced space and made sense of place at the backdrop of their relocation and the kind of basic services the community has received. The study has made use of participant observation, in-depth interviews and focus groups to collect data from community members and state representatives. It describes state responses to informality in communities, with focus placed on the N12 Highway Park informal settlement. It further explores the identities forged by community members in relation to their own perceptions of space and the use of shared state provided facilities; methods behind individual shack renovations; and the establishment of social spaces. The research concludes that service delivery shapes the community’s perceptions of the state and of their lived environment. Furthermore, perceptions of space have shaped spatial production and finding a sense of place through forms of attachment and detachment by community members. This spatial understanding suggests that space is at the centre of people-state relations. Space is therefore shaped by various actors and in the case study of the N12 Highway Park informal settlement: space production as a concept and practice serves as a tool to understand how informal communities give value to their lived environment.MT 201

Health seeking practices amongst primigravidae in the Gauteng Province, South Africa

ABSTRACT This abstract provides a brief summary of the research study (Nieswiadomy, 2002). The South African report on confidential enquiries into maternal deaths identified delayed and/or infrequent antenatal care as a significant avoidable factor contributing to maternal mortality in South Africa (SA) (Department of Health (DOH), 2001). There are still women in South Africa whose first antenatal care contact with the midwives obstetrical unit (MOU) is in the third trimester of their pregnancy. The aim of this study was to determine the health seeking practices amongst primigravidae at a level 1 MOU, based in a peri-urban area in Gauteng province, SA. The health seeking practice of concern was antenatal clinic attendance. The research design was qualitative, descriptive, exploratory and contextual. The research method implemented was unstructured individual in-depth interviews. The population consisted of primigravidae who were attending antenatal clinic at a level 1 MOU. The sample consisted of primigravidae who booked at the level 1 MOU’s antenatal clinic in the third trimester of their pregnancy. Maximum variety purposive sampling, with inclusion and exclusion criteria, was used and sampling continued until data were saturated. The sample size consisted of 10 participants whereby 2 of them were the pilot study and eight were the interviews that followed the pilot study. Data were collected by means of individual in-depth interviews. One question was asked: ‘What experiences influenced you to go for your first antenatal visit when you did?’ Interviews were audio taped, transcribed and analyzed by using Tesch’s eight steps of data analysis (Creswell, 1994). Lincoln and Guba’s four strategies for trustworthiness were applied and ethical considerations were implemented. The results were discussed under two themes. Those themes were: needs, and delayed booking. The recommendations were made regarding the recommendations that arose from the study, recommendations for research, nursing practice and nursing education

Engineering Fluorescently Labeled Human Fibroblast Growth Factor One Mutants and Characterizing Their Photophysics Properties Towards Designing FRET Assays

Human fibroblast growth factor one (hFGF1) belongs to a family of 22 FGF members produced by fibroblast cells. Cell signaling during physiological processes of angiogenesis and wound healing occurs when hFGF1 binds to its receptor (FGFR). However, when heterogenous homeostasis is not maintained, fibroblast cells exhibit excessive proliferation which can lead to a myriad of cancers. smFRET is an ultrasensitive distant dependent (1-10 nm) technique capable of resolving such heterogeneity in structural dynamics and binding affinities (Kd). Therefore, we successfully designed and characterized fluorescently labeled hFGF1 tracers which span the visible light region of the electromagnetic spectrum for use in smFRET. Fluorescent labeling was achieved by utilizing the maleimide moiety of the dyes (Alexa Fluor, Cyanine and iFluor) to conjugate to the cysteine residues via a thioether bond. We synthesized biologically active, and site specifically fluorescently labeled hFGF1 mutants of F2C-hFGF1 (on the flexible N terminal loop) and T79C-hFGF1 (on the rigid loop between β strand 7-8). The main findings showed that the dye and protein required a certain degree of flexibility to obtain high labeling efficiency but having too much flexibility caused low labeling efficiency because of entropic penalty during conjugation. Ensemble and single molecule level characterization of the photophysical parameters of ensemble QY, fluorescence lifetime and molecular brightness revealed that the dyes properties depended on the rotational and vibrational degrees of freedom of the dye on the protein, dye structure and degree of flexibility of the labeling site. Overall, we successfully fluorescently labeled hFGF1 at specific sites and characterized its photophysical properties as this information is critical in designing FRET assay

Community engagement in higher education: Developments after the first institutional audit cycle

This study explores how three universities have responded to the Higher Education Qualifications Committee (HEQC) recommendations regarding deficiencies in implementing their community engagement (CE) missions. The Education White Paper 3 locates community engagement within the policy changes of transformation in higher education. However, literature reveals that there is still considerable resistance to accepting CE as a core function of universities. This study is qualitative and uses document analysis to understand the extent to which three universities identified for this study have progressed regarding their CE missions. The documents analysed include HEQC first audit cycle reports, policies, strategic plans, annual reports and institutional websites. Open Systems Theory (Emery) was used to underpin the findings of this study. The results revealed that despite the challenges reported in the literature, universities had developed policy frameworks to facilitate understanding of the concept among internal stakeholders and put structures for managing CE initiatives

Developmental local government as a catalyst or an impediment towards a South African developmental state

Includes bibliographical references: leaves 201-224South African authorities formalised their goal to pursue a developmental state with the adoption of the National Development Plan (NDP) in 2012. It is clear from the reading of the NDP that the authorities are convinced that the developmental state approach is a cause for development. The declaration to construct a developmental state is interesting at best or bizarre at worst in that developmental states are often identified by assessing their (economic) performance over a period. They hardly sought out to intentionally build developmental states. The South African governance system has implications for a quest to construct a developmental state. Whereas the literature on East Asian countries tends to focus on the role of central governments in economic development, the South African governance places a huge emphasis on cooperative governance between the three spheres of government. To this end, the constitution spells out the specific developmental objectives that must be pursued by municipalities. This essentially means that the system of cooperative governance, and the extent of effectiveness of local government, will either catalyse or impede the realisation of South African developmental state. Developmental states are often distinguished from others by their structures, roles and outcomes. Their structures and roles are developmental and are a cause for soaring outcomes. This logic was employed to analyse the nature of structures and roles in eight (8) selected municipalities over a 15-year period and how these influenced the actual policy performance. Findings that emerged from over 30 interviews with high ranking officials in various institutions and the thorough analysis of a number of documents confirm that structures and roles in municipalities are far from being developmental. The study also found that informal factors have effectively ‘juniorised’ local government as a sphere of government despite the constitution emphasising the equality of all three spheres. In the final analysis, local government is incapacitated to carry out its developmental mandate. It is against this reality of incapacitation of local government that the study argues that the performance of local government, measured against its constitutional objectives, effectively impedes the realisation of a developmental state in South Africa.Development StudiesD. Litt. et Phil. (Development Studies

Correlation of mining pit depth and flotation recovery of oxidized platinum group mineral ores

Abstract: South Africa (SA) has a total of three reefs from the Bushveld Igneous Complex (BIC), which are mined and processed for the recovery of Platinum Group Elements (PGEs). The three reefs are Merensky, the UG2 and the Platreef (Mungall & Naldrett, 2008). The Platinum Group Minerals (PGMs) are mostly sourced from the UG2 reef because they are easy to recover as compared to Merensky and Platreef (Hey, 1999) by froth flotation. The froth flotation concentration process has been at the forefront in concentrating the PGMs from their perspective ores. Different concentrating circuits have been developed and these are aimed at floating mainly the sulfide minerals. Despite success in floating the sulfide minerals, significant complications are being encountered when it comes to floating weathered ores. Poor recoveries and high chromite grades are achieved when using the current conventional processing circuits due to complex mineralogy of oxidized ores (Becker, et al., 2014; Bulatovic, 2010; Cramer, 2001)...M.Tech. (Extraction Metallurgy

Impact of ecophysiological factors on biocontrol of aflatoxin contamination of maize by atoxigenic aspergillus flavus strains

This study has (a) evaluated the biodiversity in toxigenic mycobiota associated with maize from subsistence farmers’ stores in five climatic regions of Lesotho in two seasons, (b) compared the effect of ecophysiological factors on interactions between atoxigenic (AFL-) and toxigenic (AFL+) Aspergillus strains and control of aflatoxin B1 (AFB1) contamination of maize, (c) examined the mechanism of action of AFL- strains in relation to mycelial growth rate, sporulation, germination rate, germ tube extension, C-source utilisation patterns and hydrolytic enzymes and (d) examined ecophysiological approaches to enhance competitiveness of the atoxigenic strains. Cont/d

Geotechnical conditions, community-based practices and developments in Slovo park informal settlement, Johannesburg

A research report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, in fulfillment of the requirements for the degree of Masters of Built Environment in Housing.In recent years, authorities, experts and environmental agencies have had to deal with the challenge of considering dolomitic zones for the in situ upgrading of urban informal communities. South Africa appears to lead many regions globally in the management of developing construction methods on dolomitic terrains. The benefits of such expertise are, however, not yet visible in informal settlements. Intervention envisaged by the Constitution, various laws and regulations seem to have little effect. The challenge remains: the need to significantly improve the economic prospects and livelihoods of residents of informal settlements. Lack of such interventions is driving dangerous practices that exacerbate the development of dolomitic hazards, such as sinkholes. The informal settlement of Slovo Park was selected for the study because it is built on dolomite and at present there are major on-going debates between the City of Johannesburg (CoJ) and the community around issues of residential upgrading in relation to possible geotechnical hazards materialising in this area. The aim of the study was to investigate and define human actions that can exacerbate the formation of sinkholes within this type of setting. This research also strives to illustrate the gap that exists between conventional geotechnical interventions, and the important key roles that informal communities could play in preparing for and mitigating dolomitic risks. The study recommends the adoption of a Dolomite Risk Management protocol, as well as social awareness programmes, to inform residents of the negative impacts that socio-cultural and household practices and decisions can have on sinkholes creationMT 201

Mould Contamination of ready-to-eat cereal-based foods retailed in lesotho with special reference to toxigenicAspergillus flavus

Samples belonging to four different brands (Instant Morvite™, E-Papa™, Ace Instant Porridge™ and Roasted Morvite™) of ready-to-eat fortified cereal-based foodstuffs imported from the Republic of South Africa were bought from different retail outlets in the Roma valley, Lesotho and examined for contamination with moulds. All (100%) of Roasted Morvite™ and E-Papa™ examined were contaminated with fungi. The greatest average fungal load (1.33 × 105) was recorded on Roasted Morvite™samples. Although all the E-papa™ samples were contaminated, the upper limit average mould load (1.0 × 104) was the lowest compared to other brands that were analysed. A total of 226 isolates belonging to five different genera (Aspergillus, Penicillium, Cladosporium, Wallemia and unidentified genus) were recovered. For each of the brands assessed, average mould counts for some samples were above maximum permissible limits (103 CFU/g) established by World Food Programmeguidelines for fortified blended foods. Aspergillus and Penicillium isolates exhibited greatest fungal population densities, 52.7%, 36.3%, respectively. Wallemia was the least frequently isolated genus in this study; only four isolates (1.8%) recovered from all the samples investigated belonged to this genus. Of the Aspergillus speciesisolated, A. niger had the greatest relative density (39.5%) followed by A. flavus (37.8%), while Aspergillus amstelodami and unidentified Aspergillus species had the lowest. Of the 22 A. flavus isolates tested for sclerotia production potential, 18 produced large sclerotia with average diameter > 400.02±82.61 on Czapek solution, agar. Ten (56%) of these isolates were toxigenic as evidenced by formation of a blue fluorescence on the reverse of the plates when observed under UV (365 nm). It was concluded that the detection of above -permissible limits levels of moulds and aflatoxigenic fungi in some samples analysed presents a risk to consumers’ health. Itis, therefore, suggested that a statutory, independent and science-based body dedicated to protecting public health and consumer interest in the area of food safety and hygiene be established. The main function of such a body would be to take all reasonable steps to ensure that food produced, distributed or marketed in Lesotho meets the highest standards of food safety and hygiene available