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Item The Quantitative Hydrogeological Mapping of Zebediela Estates, Central Transvaal(University of the Witwatersrand, Johannesburg, 1970-05) Pretorius, Desmond AubreyThe groundwater system on zebediela Estates, situated along the northern edge of the Springbok Flats in the Central Transvaal, has been studied by physiographic, geologic , geophysical, geochemical, and hydrologic methods . Emphasis has been placed on the subsurface mapping of the spatial distribution patterns of a nvn1ber of hydrogeologic parameters, and computer-based polynomial trend surface analysis has been employed to facilitate the interpretation of the maps. The computer has also been used to determine the general statistics of the frequency distributions of the various parameters and to platform sequential multiple linear regression analysis in an attempt to determine the relationships between the variables . Data arrays of observations, computations, and interpretations have been disp layed in 38 tables in the text and 21 appendices to the text . The distr ibution patterns , in one and two dimensions, have been portrayed in 8 text figures and 117 maps, separate from the t ext. The area studied covers approximate ly 23 square mil es, in which 556, 000 orange trees have been planted on 5800 acres . An average annual amount of 2400 million gallons of water is required to maintain t he operation, and 560 million gallons of this quantity are withdrawn, on the average, each year from boreholes tapping the groundwater resources of the Estates . Up to April, 1969, 315 holes had been drilled, and 151 had become producers at one time or another. In 19 years of exploitation between 1950 and 1968, 10, 600 million gallons of groundwater were withdrawn, at an average rate of 13 million gallons per year per production borehole. The study has shown that the groundwater system supplying this substantial quantity of water consists of two main elements - a piedmont alluvial slope, in which stream channels and paleochannels on coalescing alluvial fans are acting as conduits for the transmistion of water from the intake areas; and an underlying bedrock storage reservoir composed of aquifers of the Transvaal and Karroo sequences . The Malmani dolomite aquifers and the Stormberg basalt aquifers are superior to those of the Wolkberg quartzites, shales, and lavas, and the Stormberg Cave sandstones. It has been possible to distinguish two cycles of Karoo basalts, each of which shows differentiation . The upper cycle is far more important as an aquifer than the lower cycle. The piedmont slope is composed of portions of three alluvial fans , the spines of which have a general southeasterly trend towards the junction of the Nkumpi and Olifant rivers in the valley-flat environment well to the south of the Estates . The upland areas above the apices of the fans embrace the mountain ranges which form the northern rim of the Transvaal Basin, and these uplands have suffered right-lateral movements along extensive east-northeast-trending transcurrent faults which must have continued to be active into recent times in order to displace the stream course on the fans. The fan-head section and portion of the midfan section of the Nkumpi fan, in which the Gompies River is situated, occur over the east-central, eastern, and southeastern parts of the property, and, where underlain by the upper basalt aquifers, constitute the most important source of groundwater on Zebediela Estates. The whole of the fan-head and mid-fan sections of the Mamukebe fan are located in the riorthern, west-central, western, and southwestern localities of the area studied. The fan is much smaller than either of the others, and is underlain by Wolkberg rocks, Cave sandstones, and lower basalts. Its overall groundwater potential is consequently lower than that of either of the other two components of the piedmont slope. Only a very restricted portion of the fan-head section of the Mogoto fan occurs in the extreme northwestern corner of the Estates, where it is underlain by the dolomite aquifer, Its groundwater parameters are consequently very favourable, but the true potential of this fan lies beyond the western boundary of the property. The average yield of boreholes in the upper basalt is 3600 gallons per hour; in the lower basalt, 2000 g.p.h.; in the sandstone, 1500 g.p.h.; in the dolomite, 11,200 g.p.h.; and in the quartzites, 1500 g.p.h. The average yield for all boreholes on the Estates is 4100 gallons per hour. All of these figures are appreciably higher than those for equivalent formations elsewhere in South Africa, testifying to the impoi,tance of the piedmont alluvial slope environment in the overall groundwater system at Zebediela. The average annual recharge of the groundwater reservoirs from all sources has been estimated at 700 million gallons. With the average annual withdrawal being of the order of 560 million gallons, the possibility exists that production from the aquifers can be increased by 25 per cent, without fear of serious, permanent deterioration in the performance of the groundwater system. However, excessive exploitation in times of low recharge might lead to the development of quality h.azards with respect to sodiuum, ehloride, and bicarbonate over the upperbasalts. This possibility does not exist for the remaining aquifers, particularly those in the dolomite, from which relatively pure water is drawn. An added problem in the recharge of the upper basalt aquifer is the contamination of t he groundwater in storage by lithium, brought into the Zebediela groundwater- system by the Nkumpi River, which transmits the element from the granite terrain to the north of the mountainous rim of the Springbok Flats. A new model of groundwater exploration has been devised, based on optimum drilling sites being located where coincidence takes place of piedmont stream channel conduits, dolomite or upper basalt aquifers, and transcurrent fault aquicludes, Results obtained from the employment of this model during two years of drilling subsequent to its development in a preliminary form produced an increase of 14 per cent in the average yield of all boreholes drilled.Item Optimisation of fragmentation at south deep gold fields mine: a case study(2020) Nong, MatsobaneA fundamental aspect of an efficient mining operation is the steady movement of material throughout the mine system; particularly the flow of ore from the upstream excavation point to the downstream processing or stockpile site(s). This can be achieved by attaining an optimal fragmentation size from drilling and blasting suitable for subsequent mining process such as loading, hauling and crushing. Drilling and blasting are the first fragmentation process and is currently the most economical technique of fragmenting hard and competent rock especially for deep-level mines where operational costs are high. The aim of this research is to analyse and optimise fragmentation to improve the oreflow efficiency at South Deep Mine in South Africa. The mine experiences coarse fragmentation that cannot pass through 300mm by 300mm grizzlies. As such, secondary blasting is often done to reduce the size of boulders either in the stopes or on top of the grizzly which leads to a reduction in productivity. Although coarse fragmentation is reported in the stopes and on top of grizzlies, the plant is reporting fine fragmentation that is not suitable for the ball mill. This results in reduced gold recoveries. To get a better understanding of the fragmentation size distribution achieved, fifty-one images of the muckpile from five stopes were analysed using the Split-Desktop software. The analysis showed an overall F80 passing of 287.48mm, which is less than the 300mm grizzly size implying that the fragmentation size achieved is adequate. However, looking at the overall particle size, the Rosin-Rammler distribution was found to be 0.80. This infers an inconsistent fragmentation where the mine produces both coarse and fine fragmentation size. The AEGIS Underground drill and blast software was used to analyse the drill and blast design patterns. The analysis showed that the design toe spacing varies from about 0.5m to 7.5m in the same blast. Due to the software’s limitations, the break model analysis was only run for toe spacing between 2m and 7.5m. This showed that there is no overlap between blastholes which may be the source of the coarse fragmentation size. Fine fragment size may be as a result of blastholes which are close together, i.e. 0.5m. Although not tested, the impact of blasting stresses emanating from primary stopes may result in fractures in secondary stopes which will have a greater impact on the propagation of the shock wave and high-pressure gases between the blastholes and consequently the fragmentation distribution size. It is recommended that the mine change their drill and blast pattern. The mine must change from 76mm blasthole diameters and introduce a larger blasthole diameter of 89mm blasthole diameter. Not only will this diameter improve drilling accuracies but will reduce the fragmentation size distribution. It is also recommended that the mine maintains a ring burden of 2m throughout despite an increase in the blasthole diameter. For the first design, the toe spacing must also be 2m followed by increments of 0.5m per blast until a suitable fragmentation distribution size is achieved. After which, the toe spacing must be kept constant. It is important that South Deep Mine continually evaluate the fragmentation size distribution achieved from each blast for optimisation purposes. Therefore, a blast management system is important.Item External change management: the revised policy of registered construction health and safety agents in South Africa(2021) Khoza, Sepelong RebeccaPurpose: South Africa’s construction industry continuously strives to improve its health and safety( H&S). Consequently, South Africa revised its Construction Regulations in 2014 to include the requirement for the application for construction permit to include a competent construction health and safety (CHS) agent. This research investigates how change management processes enable construction companies to effectively comply with the revised H&S policy requirement. Design/methodology/approach: Using a cross-sectional survey design, an online structured questionnaire was sent to SACPCMP-registered construction professionals and construction professionals of a state-owned enterprise in South Africa using purposive sampling. 170 construction professionals responded (85% response rate). Likert scale/ ordinal data were collected on the factors affecting the registration for the CHS agents (Objective 1), understanding of the implications of implementing the revised H&S policy (Objective 2), applicability of the different change management strategies (Objective 3), and the attitudes towards organizational changes for implementing the revised H&S policy (Objective 4). Findings: There was a strong agreement that H&S is best implemented in the early phases of construction project (Objective 1). Average understanding existed that any person who is interested in being an H&S agent can become one by going for an interview only(Objective 2). Also, there was a strong agreement that project participants’ need to comply with the changes as required by the law (Objective 3) and that the attitude of top management towards change is positive (Objective 4).Research limitations/implications: The construction professionals acknowledge that the revised H&S policy needs to be adhered to, as per the law, however there are hindrances to being registered because of factors that can be sorted out by management and how they roll out the change management within the companies. Originality/ Value: The Ingenuity of the research is based on the change management in the context of the revised H&S policy in South AfricaItem A bathhouse in Cyrildene - a phenomenological approach to the design of a bathhouse in Johannesburg(2021) Kow, AlanIn Johannesburg, there is a lack of global bathhouse typologies. They either don’t exist or are in a form which caters to a niche subculture. Bathhouse culture has been around for hundreds of years and many people around the world take advantage of it as a form of communal bonding, relaxation and general hygiene. In addition to this, when done correctly, it has the effect of stripping away of social class and distinction as well as providing a safe and entertaining environment for those within its walls. This study aims to bring my personal experience of an East-Asian bathhouse into Cyrildene, a predominantly Chinese neighbourhood, that is slowly losing its cultural identity. Building on existing data on historic bathhouses from around the world, it asks: How can the concept of phenomenology be used to guide the design of an Asian style bathhouse in order to enhance the Asian/Chinese cultural experience and help in the revitalisation of Derrick street as a distinct cultural hub In Johannesburg? The main methodologies that will be used in this report will be from literature reviews on historical analysis of bathhouses around the world but more specifically in Eastern Asia. One on one interviews with the residents and shop owners living in Cyrildene as well as the owner/s of a spa. Observations based on mapping and photography will also be employed. The last will be the use of auto-ethnographic data from my own experiences. The main hypothesis of the report will be seeing if the bathhouse typology through the use of a variety of different programs that range from bathing to eating to sleeping in addition to the application of architectural phenomenological theories helps make it suitable for Cyrildene and thereby revitalise and strengthen the areas existing cultural identity.Item A comparison of various modelling techniques to optimise production rate on a platinum mining project(2021) Dreyer, JacoEvery business aims to create an optimal economic value for its shareholders. The production rate is one of the critical drivers of value in the mining business. Several approaches have been developed to determine the production rate for mining operations. This study applied three approaches for determining production rate, namely the tonnage-based, microeconomic and marginal-analysis modelling methods. These methods were applied on a platinum project, and the production rate results from the three methods were used to determine the life of mine (LOM) production profiles, capital expenditure (CAPEX) and operational expenditure (OPEX). These results were then used as inputs into a discounted cash flow (DCF) model. The DCF model results were compared and analysed to determine a production rate determination method that results in an optimum production output rate for the project. The study revealed that the tonnage-based modelling technique resulted in the highest production rate of 410-kilo tonnes per month (ktpm), the highest CAPEX of USD957.24 million, the lowest OPEX of USD75.37 per mined tonne, the highest net present value (NPV) of USD63.12 million and the highest internal rate of return (IRR) of 12.85% over a 40-year LOM. The microeconomic modelling technique ranked second with a production rate of 270 ktpm, CAPEX of USD 726.24 million, OPEX of USD 76.68 per mined tonne, NPV of USD 3.46 million and IRR of 10.17%. The marginal-analysis modelling technique ranked last with a production rate of 230 ktpm, CAPEX of USD 658.76 million, OPEX of USD 77.83 per mined tonne, NPV of USD -10.69 million and the lowest IRR of 9.47%. Mineral Resource tonnage-based modelling may be further investigated in other commodities other than platinum or other multi-element/polymetallic mineral deposits in line with the South African mining industry. This will result in the formulation of industry-specific calibration in the South African mining industryItem The polymorphic state and real estate: rethinking the relationship between the state and real estate through Johannesburg & Bangalore(2022) Pillay, SaritaThis research seeks to expand understanding of the relationship between the state and real estate. It is guided by the impulse, from experience in urban land justice activism, to acknowledge multiplicity in the state, and to contextualise the nebulous boundary between the private and public. I argue that commonly adopted concepts in critical scholarship – in the strands of urban power, urban planning and historical materialism – do not adequately offer a means to do this. Thus, drawing from how these concepts have been stretched and refuted in critical scholarship, an analytical lens is assembled for this research. It is guided by three influences: a historical materialist analytic of the urban; non-normative approaches to a postcolonial state theorised in India; and insights on the amorphous boundary between the state and private sector in real estate The starting point for this research is Johannesburg. However, an expansive spectrum of Indian critical scholarship surfaced in reading the relationship between the state and real estate. This raised the methodological utility of bringing Johannesburg into empirical conversation with an Indian city. Emerging organically as this city was Bangalore. Rather than ‘cases’, Johannesburg and Bangalore are approached as ‘vantage points’ through which to explore the relationship between the ubiquitous, albeit socially constructed, state and real estate. This research was thus guided by the question: (How) can the relationship between the state and real estate be conceptualised through Johannesburg and Bangalore? To begin to explore this, I undertook in-depth interviews with 62 key informants in real estate and government, as well as observations in real estate conferences and as an intern in a real estate consultancy firm. Additional analysis was undertaken of news articles, industry reports and building statistics. Three lesser-seen relationships between the state and real estate emerged, grounded in each city but developed through each other: an enabling relationship between local government and real estate shaped by the post-apartheid transition in Johannesburg; central government’s incorporation of real estate in Bangalore; and the Government Employees Pension Fund’s (GEPF) embeddedness in Johannesburg real estate as an ‘investor state’. In a landscape of differentiated real estate, the state was shown to be central to financialised forms of real estate – but not only so. This contributes to conceptualising a polymorphic state and real estate. Empirically, this work expands critical scholarship to direct considered attention to non-corporate forms of real estate in India, and listed corporate real estate in South AfricItem The underrepresentation of technical women in executive and board of directors’ roles in the ten largest listed mining companies in South Africa(2022) Zulu, NoluthandoAs with many technical industries, mining is dominated by men. It is well established that the industry has struggled with the attraction and retention of female talent. While women have made significant inroads in the industry, technical women (defined here as women who come from a geology, engineering, metallurgical, etc background) are underrepresented in the most senior decision-making roles of major mining companies. The purpose of the study was to explore this phenomenon, examining the executive committee and board composition of the 10 largest mining companies listed on the Johannesburg Stock Exchange and interviewing 30 technical women who have worked for, or currently work for, these organisations. The results demonstrate that technical women seldom advance from operations to the boardroom and, typically, play a support function while men make core mining and technical decisions. The study also finds that many technical women move into nontechnical roles for a number of reasons. Further, while attraction of women to the industry continues to rise, the studied companies are struggling to retain technical female talent. The study further highlights the significance of government intervention concerning the inclusion and advancement of women in mining. It also emphasises the need for continued policy development and concludes with recommendations on how mining companies can drive both the inclusion of women in mining as well as their corporate advancement.Item Foraging for Earth: resurrecting the heritage of ochre through land reparation of an iron ore mine(University of the Witwatersrand, Johannesburg, 2023) O'Maker, Simone; Felix, SandraThis thesis aims to extract concepts, ideologies and theories viable to the rights of land. To rewrite a set of spatial relations that deeply grapple with the remnants of the Ngwenya mountain, in an iron-ore mine within the Kingdom of Eswatini, as an archaeological, cultural, ecological and geographical site. Foraging for Earth aims to mend its wounds that gives back the earth its dignity. It questions what architecture arises from seeing the land as a living being and to what extent it can form a relationship with a post-mined landscape. The concept of the design is derived from the site’s scar, a palimpsest of narratives rooted to memory, decay, healing and regeneration, and thereby interprets reparative strategies into a living archive that aims to reclaim what the landscape used to be. The program includes an earth reparation facility, a knowledge-sharing centre, an ochre sanctuary, craft studio and a sculpture garden. Constant visual and physical engagement encourages one to be aware of the land’s rich narrative.Item Mwana Wevhu (Child of the soil): Enhancing subsistence cotton farming through education with production creating employment opportunities in Marondera, Zimbabwe(University of the Witwatersrand, Johannesburg, 2023) Mafemba, Simbarashe A.; Kirkman, DeborahCotton plant production in Zimbabwe has witnessed a concerning decline. This cash crop, crucial for the country’s economy, has unfortunately become a harbinger of poverty among diligent farmers. Nonetheless, there is a glimmer of hope on the horizon with the adoption of sustainable farming practices, including the use of organic seeds, which can reduce pesticide usage and water requirements, potentially revitalizing cotton production. Marondera, an agricultural hub, predominantly relies on subsistence farming methods to cultivate this labor and capital-intensive cash crop. Regrettably, these methods have proven inefficient for achieving profitability, ultimately pushing farmers further into poverty. The objective of my research is to delve into the realm of cotton farming, seeking avenues to enhance its viability and sustainability, thereby empowering farmers and fostering employment opportunities within associated industries. Cotton cultivation presents a multitude of job prospects, particularly during the processing phase. As part of my architectural intervention, I aspire to design a community Research Centre in Marondera. This center will serve as a knowledge hub, equipping cotton farmers with the expertise and techniques needed to cultivate the crop efficiently and sustainably. A pivotal aspect of the design will be the incorporation of vernacular architecture and locally available materials, ensuring that the architecture aligns with the practical needs of the local population it serves.Item Stories of the Forgone Forlorn Forgotten Space: Interrogating Mdantsane’s Liminal Space in which Ritual Operates(University of the Witwatersrand, Johannesburg, 2023-09) Xhegwana, Buhle; Maape, SechabaThe proposed site is located on Golden Highway in Mdantsane, Eastern Cape, and is a vacant plot of land adjacent to Mdantsane Correctional Services. The site situates itself in close proximity to multiple educational institutions and commerce, centrally within the township. The proposed research aims to analyse how Amasiko (cultural practices and their memory) within a non-transcribed culture can be translated into a built form that would be representative of its people. The built form would be envisioned as a container for memory where the ethnographic layering of information becomes a tool to access the ritual and its memory as a “Grand Mnemonic Device” to relay import ant aspects of the culture and its history (Trieb, 2013). The space envisaged must promote the acts of remembering and collecting as a tool in the process of creating a “house of memory” (Bahloul, 1992). This assembles what was not transcribed into a physical, experiential manifestation by creating a stronger link between architecture and society, looking beyond the merely functional state of architecture represented in the context. The program enacted in the space will mirror the act of the ritual by providing spaces that relate to the processes of the ritual in their various stages of the procession. The three main ritual processes focused on include Umgidi (Initiation ceremony), Umshado (wedding) and Umngcwabo (Funeral). The spaces proposed function as a tool to access the memory and ritual through its organisation while its program reaches out to the community. The program includes a community hall centred around the acts of song, dance and sermon; a kitchen to be used during gatherings and as a link to food security outreach; urban farm facilities to service the kitchen and community; discussion rooms for skill sharing, dialogue, non-transcribed learning and storytelling; video exhibition spaces to immerse oneself in the memory; a foyer with a primary focus on cleansing or washing hands before crossing the threshold into the space; storage and offices for facilitators of the space.Item Inheriting Resonance: Regenerating Indigenous African Musical Pedagogy Through an Education and Culture Centre in Newtown(University of the Witwatersrand, Johannesburg, 2023-09) Bopela, Bonnie; Gwebu, Nomonde; Felix, SandraIndigenous African Music requires spatial interventions to counter its erasure in a South African education system that has historically prioritised Western Art Music. This research analyses the relationship between African musical pedagogy and architecture. It aims to address the erasure of musical knowledge through an architectural design that evokes regeneration in an urban setting. Using Pallasmaa’s theory of phenomenology as a guiding focus, this research contextualises African music and how it manifests architecturally. The haptic and embodied architectural experiences defined by phenomenology are inherent within African music. By focusing on the musical bow instruments at the centre of many tribes across Southern Africa, the intrinsic qualities of these instruments are translated and abstracted to form an embodied architectural design intervention embued with an African musical identity. This research argues that phenomenological architectural design methodologies can regenerate, preserve and sustain indigenous musical knowledge(s) for future generations.Item Ponte; Realness. Symbiotic parasitism in drag(University of the Witwatersrand, Johannesburg, 2023-09) Georgiev, Victor Geoergiev; Bahman, DirkThe intended investigation explores queer identity and the extent to which it can symbiotically co-inhabit an outdated structure to create social cohesion and integration resulting in a regeneration. Consisting of interventions exploring identity representation and familial programmes to create a sense of community. Research focuses on vulnerable communities present within Ponte (a structure containing aspects of familiarity to Ballroom spaces) and their synergy with the Ballroom community in Johannesburg. Through architectural processes engaging with space making and programming, aims value the creation of space. Encouraging educational models through social engagement which facilitate acceptance, sex, and gender expressions through a mutual occupation. Theories identified in queer spaces and Hertzburgers writings provide solutions through familiarity and atmospheres that allow for a symbiosis of community. Research outcomes indicate an adaptive re-use of Ponte through a reprogramming relating to investigations that highlight the buildings previous intentions as a vertical city.Item Discrimination between nearby and direct lightning strikes to a long operational medium voltage line to assist in the determination of the basic insulation level (BIL)(2024) Van Schalkwyk, Willem Jacobus DirkseThe lightning performance of a Medium Voltage (MV) line needs to be divided into two categories: lightning performance due to nearby lightning and direct lightning strikes. A better nearby lightning performance requires a higher Basic Insulation Level (BIL) while the direct lightning performance requires a lower BIL to minimize equipment failure. The electromagnetic coupling models for calculating the Lightning Induced Overvoltage (LIOV) on a line are complicated and reliant on accurate input data. Therefore, short floating lines (< 3 km) were used to calculate the line’s lightning performance. The models were then verified with LIOV measurements on these short floating lines and the results were normalized to estimate the lightning performance of long operational lines. These estimations for long lines could never be verified due to the complexity of calculations and the cost and logistics of equipment to do measurements on long operational lines. A new methodology to measure the lightning performance of a long operational line was developed and verified. The obstacles such as the long line length, the changing soil resistivity, the lightning channel properties and the rapid attenuation of the LIOV along the energized line have been used as an advantage in the new method. The finite soil conductivity was used as an advantage to distinguish between nearby lightning and direct lightning strikes while the power frequency current was used to determine whether the LIOV exceeded the line BIL and caused a line fault. An existing electromagnetic coupling computer model, the ATP-EMTP, was verified with the existing ERM using the same input data. The ATP-EMTP model was then extended to include the equipped long MV line. There was no existing model or measurements to which the results could be compared to. Actual nearby lightning and direct lightning strikes of which the termination point was known were used to verify the new methodology. A significant size database (consisting of 38 675 lightning flashes and 1 155 line faults over two years) was used to evaluate the IEEE Std 1410-2010 estimated lightning performance of the long line.Item Peak-to-average power ratio reduction in optical-OFDM systems using lexicographical permutations(2024) Niwareeba, RolandThe work presented in this thesis extends and contributes to the research in reducing the high Peakto-Average Power Ratio (PAPR) in optical-Orthogonal Frequency Division Multiplexing (OFDM) systems using probabilistic-based and hybrid techniques. Whereas the high PAPR problem has been extensively studied and a number of solutions provided for the conventional Radio Frequency (RF)-OFDM systems, there are only a few solutions proposed specifically for PAPR reduction in optical-OFDM systems. Although the probabilistic-based techniques such as Conventional Selected Mapping (CSLM) and Data Position Permutation (DPP) result into significant PAPR reduction performance with negligible Bit Error Rate (BER) degradation, the resulting increase in both hardware and computational complexity as a result of a large number of Inverse Fast Fourier Transform (IFFT) operations that have to be performed to generate the candidate signals is still a major drawback. In order to reduce the complexity, in this research, two techniques which are applied in opticalOFDM systems are proposed. The first technique is the hybrid method composed of a modified CSLM and µ-law companding techniques called Low Complexity Hybrid Selected Mapping (LCHSLM). The proposed method achieves almost 50% reduction in complexity compared to CSLM with less BER degradation. The second technique based on lexicographical permutations called Lexicographical Symbol Position Permutation (LSPP) works by dividing the optical-OFDM symbol into a number of sub-blocks and performing lexicographical permutations to obtain the candidate signals after the IFFT operations. In the proposed LSPP, all the candidate permutation sequences are not obtained at once unlike in the DPP where the number of candidate permutation sequences increases at a factorial rate of growth as the number of sub-blocks increases resulting in a more complex system. Additionally, the research proposes an algorithm where a threshold PAPR value is introduced and the candidate signals are generated until a candidate with a PAPR value less or equal to the threshold is obtained. The results show that the complexity in terms of IFFT operations can be reduced substantially depending on the selected threshold and the number of candidate signals. Furthermore, the research introduces a new algorithm based on the global gain (net gain) to determine the most suitable number of permutation candidate sequences to achieve a reasonable PAPR reduction performance without increasing the time and hardware complexity to levels that the systems cannot tolerate.Item Reducing water absorption characteristics of kraft paper reinforced with modified nanoparticles(2024) Katun, Mohammed MahmoodThe inherent hydrophilic characteristics of cellulose wood fibre compromise the dielectric properties of kraft paper insulation that is used mainly in oil-insulated power transformers. This thesis, therefore, presents a novel material design model of nanocomposite kraft paper with improved hydrophobic properties for power transformer insulation applications. The concept of nanodielectric kraft paper design was used. Rutile-titanium dioxide nanoparticles (rutile-TiO2 NPs) were selected as the nanofiller. Compared with other metal-oxides, rutileTiO2 NPs are stable in chemical reactions, have good thermal stability and also have high electrical resistivity. Rutile-TiO2 of 19.72 nm diameter were fabricated using the sol-gel method and then used in reinforcing the kraft paper to produce a nanocomposite kraft paper with improved dielectric properties. Since the nanoparticles are inherently hydrophilic, and the intention is to produce a hydrophilic nanocomposite kraft paper, a technique was devised to make the NPs hydrophobic. The rutile-TiO2 NPs were surface conditioned with two alternative surfactants; Alkyl ketene dimer (AKD) and alkenyl succinic anhydride (ASA). Various quantities of the two surfactants were investigated to determine the optimal amount. The resultant surface-modified rutile-TiO2 NPs were studied to understand their hydrophilicity and thermal stability properties. It was found that the unmodified rutile-TiO2 NPs absorbed more moisture, compared with the surface-modified nanofiller, the mass increased by about 4% due to moisture absorption. The surface-modified rutile-TiO2 NPs with 5% AKD had 45% more thermal resilience than the unmodified rutile-TiO2 NPs surface and this is a significant knowledge contribution of this thesis. Using an unbleached kraft pulp, nanocomposite kraft paper specimens were fabricated with nanoparticles having varying surfactant loading. The specimens were then characterized to reveal various critical properties such as hydrophobicity, thermal, dielectric losses and dielectric strength. The version of the nanocomposite kraft paper that gave the most improved water and moisture absorption properties was that with 5vol/vol% ASA surface-modified NPs. The moisture absorption rate dropped by 74% compared to the unfilled kraft paper, and the water vapor transmission rate decreased by 30%. The contact angle of water droplets improved by 12%, and water absorption rate improved by being 4 times slower. The dielectric loss measurements showed that the nanocomposite kraft paper containing rutile-TiO2 NPs (5 vol/vol% ASA) also had 40% lower dielectric losses than the reference (unfilled) samples. The breakdown voltage of the nanocomposite kraft paper increased by about 15% while thermal withstand was improved by 5.4%. This research, therefore, has successfully improved the hydrophobic properties of kraft paper by filling it with surface-modified rutileTiO2 NP. It can be argued from the results that for power transformer application, the novel nanocomposite kraft paper developed in this thesis will improve power transformer insulation reliability design by mitigating the main agents of insulation degradation which are water and thermal stress.Item Architecture as mnemonic experiencing past, present, and future narratives in a Johannesburg cultural complex(2024) Segal, YehudaMemory is transient, it comes and it goes. It is a passing remembrance of a past time, person or place. Memory is the experience we store in our minds to recall at a future time and date. It is the friends we make on the first day of school, our childhood holidays, or beach sand between our toes. Memory is also stored in books, visuals, art, and the internet. It is the long-gone monarch in a painting, the photographs and videos of historical events that record a past time and people. And so, memory is architecture- or, simply, space. Spatial recall- the ability to remember a space or place, directions from point A to point B, is the reason we find our way when lost. The architecture of memory is related to that of structures, buildings and spaces that serve to record or preserve a past event or person, yet also the landmark that guides us. It is a museum, memorial, triumphal arch and even a religious or cultural space. It is also the old as opposed, or in harmony with, the new. Architecture as mnemonic is relatable to other aspects and devices with mnemonic value. Memory is therefore an important aspect of archi - tecture and the built world. Not only do we remember through spatial interactions, we also experience spaces which lead to us creating new memories.Item To burn or not to burn: an approach to control waste in our society highlighting the Relationship between energy, recycling and communities(2024) Kabongo, BenedictteThe capacity of South Africa and other developing countries is as minimal. On the other hand, the growing trends - population growth, industrialization, and economic growth- in modern-day society have improved human wellness. As a result, when resource consumption rises, so as solid waste. However, in developing countries, the generation of waste per capita is the lover compared to developed countries; the main challenge is the capacity to handle it effectively. Moreover, efficiently landfill, recycle and reuse. The resource consumption model in developing countries is linear, meaning that processing, producing, using, and discarding products to nature harms the environment through the emission of greenhouse gas, the pollution of land and water resource, and boost climate effect. In the last decade, solid waste management has improved technologically and operationally and responds to environmental concerns; its focus is on the end-stage solutions, focusing on the reduction of waste rather than sustainability, whose core focus is the prevention of waste. South Africa’s approach regarding solid waste is to push waste up towards minimal production, reuse, and recycling through comprehensive producer responsibility and economic instruments This research focuses on the factors impacting solid waste management in South Africa and will put forward realistic avenues for using solid waste as a resource. In addition, it will help find successful initiatives highlighting inclusive planning and management of those facilities. Finally, this finds approaches for the private sector, the government, and the community to link service and value chains in sustainable solid waste management. For example, it adopts practices that divert waste from landfills, formalizes reclaimers or waste pickers, initiates waste-to-energy technologies, and encourages recycling at all waste cycle stages.Item Improving open pit mine economics through ultimate pit slope optimization: case study of Pickstone-Peerless mine(2024) Nyamande, PardonIn most open pit mining operations the need to create stable pit slopes and the influence of the overall pit slope on the economics of such an operation is highly appreciated. Despite such knowledge many open pit mines are designed with little or no geotechnical investigations being carried out so as to come up with an optimized pit slope in line with site specific conditions. This can lead to under or over estimating pit slope angles. Conservative (too gentle) slopes result in high stripping ratios therefore a high operating cost. Slopes too steep may result in slope failures, which may lead to high operating costs or premature mine closure. This project emphasises the importance of geotechnical investigations not only for safety reasons but for economic reasons as well. A case study of Pickstone Peerless mine was used. Geotechnical data was gathered through core logging and face mapping of the existing pit. The data gathered was then used for stability analysis employing empirical, kinematics, limit equilibrium and numerical modelling. Rocscience software packages were used for numerical based analysis. From the results obtained it was concluded that it is possible to steepen the current 52o overall pit slope angle of the Peerless pit by 1o without compromising stability at both bench and regional scales. This will be possible provided adequate slope management practices are put in place and adhered to. The steeper slope would have saved the mine more than 2,681,110 m3 of waste stripping, translating to in excess of $12,064,995.00 (USD) in financial savings for the existing pit. The steeper angle applicable to the current pit may not be appropriate to the pit extensions. Further geotechnical evaluations should be done on suitably positioned and spaced boreholes in the area of the extension, to verify the stability of steeper slopes in that area. The analysis done as part of this project was used to show that the current pit can be deepened by 5 m without a push back.Item The incorporation of unmanned aerial vehicles in a slope stability monitoring system: a Rössing uranium mine case study(2024) Shanyengana, Olga NdapewoshaliSlope stability monitoring is a safety critical input in the Slope and Dump Management Plan (SDMP) at Rössing Uranium Limited (RUL) mine. The SDMP was adopted to satisfy the requirements of the D3 standard – management of slope geotechnical hazard at the operation. Through this standard, RUL aims to provide an injury-free and safe working environment for the operation. This is achieved by proactive identification and management of slope risks and instabilities onsite. This research is a case study of the incorporation of unmanned aerial vehicle (UAV) technology into the slope stability monitoring system (SSM) at RUL, towards conformance to the D3 standard. The study highlights the safety benefits gained by removing personnel from hazardous areas and substituting them with UAVs. The utilisation of UAV data in geotechnical processes such as; the final wall assessment, crack detection and monitoring, as well as dump advancement rate calculations are also discussed. The study further investigated the use of UAVs for SSM prism inspections and proposes the incorporation of UAVs into the trigger action response plan (TARP). A concept of UAV modification for prism-cleaning operations has been developed through this research, to alleviate the challenges of prism loss in inaccessible areas due to dust accumulation on the prism surfaces.Item Urban scripting audio-visual forms of storytelling in urban design and planning: the case of two activity streets in Johannesburg(2024) Mkhabela, SolamSouth African cities reflect spaces based on Euro-American theories and norms, mapping methods, and design imperatives. At a local level, this imposition’s tool of static diagrams, plans, sections, elevation, and aerials; broader spatial plans with localized frameworks; regulatory plans controlling land use results in spaces hindering socio-economic development, especially for the marginalized, which comprises a predominantly black African and poor cohort. Consequently, current practice must significantly improve a city’s engagement with everyday users. Based on the indicated need, this thesis argues that the first step to effective urban design is accurately ascertaining spatial needs. In responding to current city-making practices that create ineffective spatial outputs, the study introduces Urban Scripting as a novel transdisciplinary and practice-based approach for assessing inhabitable urban locations. Its methodology in city-making processes strategically inserts social narrative to enhance understanding of daily user experiences. In creating accessible ways of exposing urban layer details, the procedures combine Nguni oral tradition (local expertise) with audio-visual (disciplinary knowledge) as a hybrid narrative technique that simultaneously analyzes and produces. Here narrative suggests using story to amplify an evolving discourse unit that writes and communicates spatial imagination. More so, storytelling, framed in and through interaction, finds people and information often missed by conventional mapping and assessment tools, specifically the voices in the ‘twilight zone,’ the space between legal and illegal on-the-ground operations. Transdisciplinary methods structure more critical and empirically on-ground evidence that inductively leads to new ways of thinking and analyzing. Practice-based casework turns space into place, builds an anthology of empirical knowledge to inform city-making methodologies, and shapes appropriate policies supporting subaltern communities. Programmatically and polemically, it explores how a cinematic frame is an inclusive tool within a specific set of urban processes. Ultimately, its enframing application calibrates an empathetic narrative, potentially transforming lives better for an African city in motion. This approach is valuable for practitioners as a firm departure from convention and thrusts Black African knowledge to the forefront, thus acting as a decolonization tool. Tested at two different sites in Johannesburg, Alexandra (formerly a Black dormitory ‘township’) and Orange Grove (once a whites-only area), the approach effectively engaged with spatial users, specifically, the microentrepreneurs whose urban insurgency practiced on the side of the street serves the broader public yet remains unnoticed by spatial practice. Urban Scripting’s methodology better understood the urban spatial challenges and needs at the Johannesburg study sites. For spatial practice site assessment, theory building, and iv practical application, it is an approach that is likely to prove equally effective in communicating bottom-up needs to help imagine and design a fair and democratic city in hundreds of other similar environments in South Africa and indeed, across Africa, where parallel realities exist.
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