OpenUCT is the open access institutional repository of the University of Cape Town (UCT). It preserves and makes UCT scholarly outputs digitally and freely available, including theses and dissertations, journal articles, book chapters, technical and research reports, as well as open educational resources.
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Open Access
The use of indigenous plant material by local authorities in amenity horticulture in the Cape Province of South Africa
(1988) Kruger, Peter; Fuggle, R F
The purpose of this study is to investigate the current use of indigenous plant material in Amenity Horticulture by local authorities in the Cape Province. It focuses on the built-up and street environments, and includes public gardens, pavements, road verges, recreational grounds, walkways and car parks which fall under the jurisdiction of local authorities. The study relates to the assertions by Bernatzky ( 1978), Poynton (1983), Dixon (1985), and Fairall (1970) that . there is a heightened interest in the use of indigenous plant species in a number of countries. It investigates what Flint (1980) calls the growing awareness amongst contemporary landscape planners towards the use of indigenous plants in landscape design. He says that the movement toward landscaping with native plants has now spread widely' but has not as yet reached its full potential. lts ultimate expression may be found in recreating natural associations of plants.
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Open Access
A bundle adjustment solution for a personal computer environment
(1990) Rommelaere, C L M
Photogrammetry is the science and art of using and measuring photographs for various purposes. The word photogrammetry literally means the measuring of something "written" with light. Various photogrammetric techniques have been developed to solve a wide variety of problems in many fields of endeavour. The bundle solution is one technique which has proven very useful and versatile.
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Open Access
Site of struggle, custodian of memory: reimagining the St George's Cathedral complex
(2023) Myburgh, Rachel Catherine; Papanicolaou, Stiliani
A collective effort from citizens transformed the cathedral into a place which they consider their spiritual home (Weeder, 2020). It has been an integral part of South Africa's transition from minority rule to democracy. The evolution of the buildings over time is significant. I have looked at the buildings as they existed previously as well as in their current form. The happenings in and around these structures is also very important. These buildings are steeped in history not only in form but also in respect of attitude and philosophy. The memory of the people of Cape Town, past and present, guide the research and design process. The buildings do not stand apart from the people but rather converse with them. Photographs, plans, and drawings (of all types), together with its written history inform the sites potential. This tells the story of a place of worship conceived in the time of conquest and colonialism, forged by struggle, and come of age as a custodian of memory.
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Open Access
The costs of traditional construction methods against modular construction methods in South Africa: the perception of construction professionals
(2024) de Jager, Ashley Mirlné; Lefoka, Mochelo
This study aims to gain insight into how construction professionals in South Africa perceive the cost of construction with regards to modular construction methods versus traditional construction methods. This study aims to compare the benefits and drawbacks of modular construction versus traditional construction methods. Modular construction involves building certain elements of the structure in a factory setting before transporting them to the construction site for assembly, while traditional construction involves building all the elements of a structure on-site. The research focuses on factors such as cost, time efficiency, quality control, and environmental impact. The study finds that construction professionals perceive modular construction leads to cost savings and improved quality control more than that of traditional construction projects. Overall, the choice between modular and traditional construction should be based on the specific needs and goals of the project and the client's specifications as per contract data. The findings of this study revealed that modular construction is perceived to be more affordable and faster to complete than traditional construction methods. The cost and duration of different stages during construction are the main factors that create cost variances. More construction professionals have experience with traditional construction projects in comparison to modular construction projects. However, modular construction produces less waste, is considered safer, and uses less labour during the construction process. Based on the findings in the study, it can be concluded that modular construction is a cost-effective and efficient method of construction that can save time and money compared to traditional construction methods. However, it is important to note that certain factors can create cost variances between the two methods, such as the cost and duration of different stages during construction. These factors are directly connected to the cost and time spent within the various stages of construction. The findings from the study revealed that during the various stages of construction; site preparation, foundations and excavations, ground floor construction, superstructure work, roof construction, external and internal finishes, and site handover, it was found that construction professionals perceive traditional construction methods to be more costly and take more time to complete in comparison to modular construction methods. Overall, the choice of construction method should be based on the specific needs and goals of the project, as well as the trade-offs between cost, time efficiency, quality, safety, and environmental impact. To gather data for this study, 91 participants participated and complete an online survey. Google Forms, a widely recognized web-based survey platform, was employed to administer the questionnaire. The survey itself consisted of a series of questions designed to assess participants' understanding and attitudes towards the topic of interest. Upon completion, the collected responses were automatically stored in a centralized database for further analysis. To analyse the collected data, the mean item score method was employed. This approach involves calculating the average score for each survey item, providing a comprehensive overview of participants' responses. The study employed a positivist philosophy, adhering to the belief that knowledge can be derived from objective observation and measurement. To achieve this, the research adopted a deductive approach, whereby hypotheses were formulated based on existing theories and then tested using empirical data. A mono-method approach was implemented, relying solely on quantitative data collection and analysis. This quantitative approach involved collecting numerical data and analysing it using statistical methods. The study was limited to a specific time horizon, providing a record of the hypothesis under investigation
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Open Access
A detailed investigation into diamond-bearing xenoliths from Newlands Kimberlite, South Africa
(2001) Menzies, Andrew; Gurney, John
This study involves a detailed investigation of diamond-bearing peridotite and eclogite from Newlands kimberlite, located on the Kaapvaal craton, South Africa. Eighteen peridotitic garnet macrocrysts (1 to 3 cm in size) containing diamond, and one with graphite, consist predominantly of lilac garnet with diamond (or graphite) ± chromite and altered silicates. The garnets are predominantly high-Cr(> 8 wt¾), Ti-depleted, and extremely sub-calcic {< 3 wt¾). However, three specimens have high-Cr calcic compositions. The chromites are Cr-rich, Ti-depleted, whilst the solitary olivine is Fo 93 .4. The sub-calcic garnets display a narrow range of trace element signatures, depleted in Zr, Y, Ga, and Ti, whilst Sr and LREE's are enriched. The [REE] 0 patterns are all very similar and display a sinusoidal shape. The most calcic diamondiferous garnet analysed at Newlands yields a [REE] 0 pattern similar to "fertile" mantle garnets. The major and trace element geochemistry of the sub-calcic garnets is similar to inclusions in diamonds and diamond-bearing peridotites world-wide. Geothennometry yields temperatures ranging from 900 to 1050 °C, equivalent to pressures of 40 to 55 kbar (based on a 37-38 mW/m2 geothenn determined from Newlands coarse peridotites). This P-T range is within the diamond stability field. Four diamond-bearing peridotitic garnet macrocrysts are Re depleted and yield a range of ages spanning from the Proterozoic (minimum TRD 1.77 Ga) to the mid-Archrean (maximum TMA 3.52 Ga). Seventeen eclogites (2 to 6 cm in size) containing diamond are dominated by coarse-grained garnet and clinopyroxene, with primary trace phases including sulphides and rutile. Alteration is pervasive and ranges from minor grain boundary effects to massive mineral (primarily clinopyroxene) replacement. The garnets have Na2O concentrations greater than 0.07 wt%, whilst the clinopyroxenes have K2O concentrations greater than 0.08 wt%. Both phases are Fe-rich and Ca- and Mg- poor relative to other eclogites from Newlands. The garnets display a very restricted range of trace element compositions and are relatively enriched in Ga, Zn, Mn and Ti, and depleted in Cr and Ni relative to most diamond-free eclogites from Newlands. The garnets have similar [REE] 0 patterns that are [HREE]n enriched. The clinopyroxenes also display a restricted range of trace element compositions (with one exception), and are relatively enriched in Ga, Zn, Zr, Mn and Ti, and depleted in Ni relative to diamond-free eclogites from Newlands. The clinopyroxenes have similar [REE]n patterns that are [LREE]n enriched. Bulle rock major element compositions (calculated assuming a 50:50 gamet-clinopyroxene ratio) are compositionally similar to ancient (Proterozoic or Archrean?) magnesian basalts. A statistical analysis of eclogites at Newlands indicates that those associated with diamonds have a discernible geochemistry. The diamond-bearing eclogites, with one exception, have textures and mineral geochemistry equivalent to Group I (and Group B) eclogites (depending on the classification scheme used). Geothermometry yields temperatures between 920 to 1080 °C, equivalent to pressures between 42 and 58 kbar (based on a 37-38 mW/m 2 geotherm), which lies within the diamond stability field. Re-Os systematics for the diamond-bearing eclogites are indicative of formation ages in the Archrean. These eclogites had 187 Os/1 88 Os substantially higher than chondritic mantle at circa 3 Ga. The Re-Os systematics, major and trace element mineral chemistry, and stable isotopes (albeit preliminary) of the diamond-bearing eclogites from Newlands are consistent with a protolith that has interacted within surficial environments. This implies the operation of plate tectonics since the early part of the Earths history. The peridotitic diamonds occur in two primary forms, namely (< I mm) single octahedra or octahedral aggregates. The eclogitic diamonds range in size from approximately 100 μm within diamond aggregates to large single crystals up to 2 mm. The dominant morphology is octahedral but there are also significant numbers of cubes and dodecahedrons, and some cubo-octahedrons. Cathodoluminescence indicates that the eclogitic diamonds grew in at least three distinct periods. FTIR spectra indicate that the peridotitic and eclogitic diamonds display different nitrogen concentrations and platelet peak positions. Specifically, the vast majority of harzburgitic diamonds are Type II (or near Type II) whilst all eclogitic diamonds are Type I, with significantly higher N concentrations. Based on these criteria, the majority of diamonds at Newlands are of eclogitic origin. Furthermore, this difference implies that the peridotitic and eclogitic diamonds at Newlands are derived from separate sources. Both sets of diamonds have type IaAB aggregation states ranging from 0 to 20 %, consistent with diamond formation in the Archrean for both parageneses. Time-averaged temperatures imply that the diamonds formed at higher temperatures than their ambient levels at the time ofkimberlite eruption. The early Proterozoic to mid-Archrean Re-Os ages obtained for both the diamond-bearing garnet macrocryst and diamond-bearing eclogites at Newlands overlap the major crustal building periods of the Kaapvaal craton ( de Wit et al., 1992). This implies that cratonic root stabilisation beneath the Kaapvaal craton is potentially coeval with crustal formation (Kramers, 1979; Richardson et al., 1984; Richardson et al., 1990; Richardson and Harris, 1997). The presence of diamond implies that the SCLM may have extended to depths of approximately 200 km by the end of the Archrean. In addition, the apparent lack of any systematic age variation with calculated equilibrium conditions implies that the SCLM and overlying continental crust nuclei have been coupled since formation. Once formed, these assemblages remain coupled and, under favourable circumstances, can survive the destructive forces of plate tectonics.