An investigation of ISO/IEC 27001 adoption in South Africa
- Authors: Coetzer, Christo
- Date: 2015
- Subjects: ISO 27001 Standard , Information technology -- Security measures , Computer security , Data protection
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4720 , http://hdl.handle.net/10962/d1018669
- Description: The research objective of this study is to investigate the low adoption of the ISO/IEC 27001 standard in South African organisations. This study does not differentiate between the ISO/IEC 27001:2005 and ISO/IEC 27001:2013 versions, as the focus is on adoption of the ISO/IEC 27001 standard. A survey-based research design was selected as the data collection method. The research instruments used in this study include a web-based questionnaire and in-person interviews with the participants. Based on the findings of this research, the organisations that participated in this study have an understanding of the ISO/IEC 27001 standard; however, fewer than a quarter of these have fully adopted the ISO/IEC 27001 standard. Furthermore, the main business objectives for organisations that have adopted the ISO/IEC 27001 standard were to ensure legal and regulatory compliance, and to fulfil client requirements. An Information Security Management System management guide based on the ISO/IEC 27001 Plan-Do-Check-Act model is developed to help organisations interested in the standard move towards ISO/IEC 27001 compliance.
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- Date Issued: 2015
DNA-based identification of forensically significant beetles from Southern Africa
- Authors: Collett, Isabel Judith
- Date: 2015
- Subjects: Carrion insects , Forensic entomology , Cleridae , Dermestidae , Silphidae , Staphylinidae , Scarabaeidae , Histeridae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5923 , http://hdl.handle.net/10962/d1017801
- Description: Necrophilous insects, if correctly identified, can provide useful forensic information. Research in this area has focussed on flies and beetles remain comparatively under-studied, partly because some adult carrion beetles are difficult to identify morphologically, as are their juvenile stages, often requiring specialist expertise in both cases. Molecular taxonomy has been proposed as a solution to these problems. DNA “barcodes" are short fragments of mitochondrial cytochrome oxidase I (COI) DNA that are anticipated to delineate species. This approach is becoming increasingly popular, but has been met with varying enthusiasm from taxonomists. This thesis examines their use in identifying forensically significant beetles.The DNA barcodes of 234 specimens of 25 forensically significant southern African beetle species from seven families (Cleridae, Dermestidae, Silphidae, Staphylinidae, Scarabaeidae, Trogidae and Histeridae) were obtained. Thirty-three initial barcode amplification failures were overcome by using primers other than the standard Folmer pair, undermining the barcode concept’s hope of universal primers that would allow even non-specialists to produce barcodes. Another 150 specimens (64%) entirely failed to yield barcodes, including 18 fresh specimens of three species of Trogidae, implying another lack of universality of the barcoding protocol. The majority of the beetles clustered with confamilials on neighbour-joining and maximum likelihood trees, but 1.3% of the barcodes failed to cluster with their respective families, raising questions concerning the associating power of barcodes. The identification tools of the GenBank and BOLD on-line DNA sequence databases identified 21% of the specimens to the species level, 6% of them correctly. There was evidence of a paralogous sequence in the Cleridae that, while supporting identification now that it has been associated with a morphological identification, would hamper attempts at identification by clustering or phylogenetic analysis.Distance and haplotype network analyses of the barcodes of six widespread species showed that they are not geographically structured. Barcodes are thus unlikely to be indicators of the region of origin of a species and will not determine whether a corpse has been relocated after death. To assess whether a different mitochondrial DNA fragment might address (some of) these problems, a 2.2 kb fragment extending from the 5’ end of the COI gene to the 3’ end of the Cytochrome Oxidase II (COII) gene was analysed for nine species. It was found that, for Dermestidae, Scarabaeidae and Histeridae, higher degrees of diversity occurred downstreamof the barcode region, but the region of highest diversity in the Cleridae was in the barcode region. Thus, finding a more reliable fragment along the COI-COII region for each family may make robust and guaranteed DNA-based identification of these beetles more likely. The possibility of a forensic specimen being incorrectly or not identified based on its barcode alone exists in about 40% of cases, even with the new barcodes reported here. Forensic science sets a very high bar in assessing the performance of its techniques, and it is concluded that barcodes currently have unsettling failure rates as court-worthy evidence.
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- Date Issued: 2015
Issues and concerns in developing regulated markets for endangered species products: the case of rhinoceros horns
- Authors: Collins, Alan , Fraser, Gavin C G , Snowball, Jeanette D
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124877 , vital:35706 , https://doi.org/10.1093/cje/bev076
- Description: A proposal for addressing rhinoceros poaching is to legalise the trade in rhino horn and adopt a regulated market approach, overturning the current trade ban. This orthodox economic prescription aims to reduce incentives to poach endangered wildlife by driving down the market price of their products via auctioned stockpile releases. Biologists are clear, however, that securing a stockpile for some species needs biological success in captive breeding programmes (CBPs), which varies markedly across species and habitats. Rhinoceros herds in a CBP would need spatially extensive terrain and costly permanent security measures; this only appears feasible for the less aggressive ‘white’ rhino. We argue that the market price would actually need to be sustained at a high level to cover protection costs over the longer reproduction cycles in CBPs and that, without extensive monitoring and the correct institutional structures being in place, legalising trade may encourage, rather than prevent, poaching. Supplementary policy measures that differentiate among consumer groups would also likely prove necessary.
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- Date Issued: 2015
Transformation, job creation and subsidies to creative industries: the case of South Africa’s film and television sector
- Authors: Collins, Alan , Snowball, Jeanette D
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67433 , vital:29087 , https://doi.org/10.1080/10286632.2013.874418
- Description: Pre-print , Many governments have tried to stimulate economic growth via policy on the creative industries. South Africa is no different but additionally has an overarching aim of achieving social and labour market ‘transformation’ to move away from the legacy of the apartheid era. The effectiveness of incentives provided to the film and television sector in South Africa are considered in terms of their stated objectives of job creation, skills and knowledge transfer and the attraction of foreign direct investment. Informed by empirical analysis of incentive scheme data and supplemented by elite interviews with key informants, some specific policy revisions are proposed.
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- Date Issued: 2015
The South African economy and internationally fuelled business cycles: an econometric analysis
- Authors: Conradie, Tiaan
- Date: 2015
- Subjects: Business cycles -- Econometric models , Econometrics
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10948/4354 , vital:20588
- Description: The objective of this study is to understand the dynamics of international monetary policy and the relationship that exists between larger more developed economies and smaller less developed economies within a policy context. The 2008 financial crisis has caused intense revival of Austrian economics due to the monetary nature of the recession caused as a subsequent effect of the stock/housing market collapse that occurred in 2007. One factor of the 2008 financial crisis that created intense concern was the extent to which the slowdown in economic activity was able to be transmitted across international borders. The South African economy was not isolated from the financial crisis by any means and experienced a significant slowdown in economic growth. By making use of data collected from the Federal Reserve Bank of St. Louis and the appropriate econometric techniques, a model is developed to study the dynamics between United States monetary policy and the South African economy. The Austrian School provides a sound theoretical framework that allows for the specification of testable propositions to verify the validity of an “Austrian” internationally transmitted business cycle. Using United States money supply, South African private consumption, South African gross fixed capital formation and the South African current account, a vector autoregressive model is specified to analyse the dynamics behind the United States and South African economy. The results of the empirical test all confirm the theoretical prescriptions developed in the literature review that monetary growth in the United States raise consumption, investment and improve the current account balance in the South African economy. This is a novel result for this study as it confirms that a large central economy has the ability to trigger economic expansions in a peripheral economy. This study further points out the inefficiencies associated with Keynesian style policy making and propagates for a movement towards a more prudent Austrian approach. Keynesian policy making through demand oriented policies have historically been more concerned with “curing” economic instability rather than preventing it. In light of this, the need for economic reform specifically within the manner in which monetary policy is conducted is evident. Aggressive monetary policy in the wake of economic slowdown is no longer effective at creating a sustainable and stable economic environment. A movement away from the monopolization of money and central economic decision making is necessary if the global economy wishes to reach economic permanence.
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- Date Issued: 2015
Beauveria and Metarhizium against false codling moth (Lepidoptera: Tortricidae): a step towards selecting isolates for potential development of a mycoinsecticide
- Authors: Coombes, Candice A , Hill, Martin P , Moore, Sean D , Dames, Joanna F , Fullard, T
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/405757 , vital:70203 , xlink:href="https://hdl.handle.net/10520/EJC167505"
- Description: False codling moth, Thaumatotibia leucotreta Meyrick (1912) (Lepidoptera: Tortricidae), can cause both pre- and post-harvest damage to citrus fruit. Not only can this result in reduced crop yield, but more importantly because of the moth's endemism to sub-Saharan Africa, it is classified as a phytosanitary pest by many export markets. An entire consignment of citrus may be rejected in the presence of a single moth (Moore 2012). Since the bulk of citrus fruit production in South Africa is exported, the control of T. leucotreta is critical (Citrus Growers Association, South Africa 2012). Traditionally, control has been achieved through the use of chemical insecticides; however, residue restrictions, resistance development and concerns about environmental pollution have substantially reduced the dependence on chemical pesticides in citrus. Research on T. leucotreta control has therefore focused on the use of biological organisms (e.g. parasitoids and viruses), which are used as control agents within an integrated pest management (IPM) programme in citrus. These biological control agents, however, only targeted the aboveground life stages of the pest, not the soil-dwelling life stages (late fifth instars, prepupae, pupae), which is the subject of this contribution (Moore 2012).
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- Date Issued: 2015
Experiences of incarcerated women who have committed intimate partner homicide
- Authors: Coombs-Brown, Chanelle
- Date: 2015
- Subjects: Incarcerated women Female offenders Women--Violence against
- Language: English
- Type: Thesis , Masters , Psychology
- Identifier: http://hdl.handle.net/10353/17406 , vital:40965
- Description: This qualitative study explores the experiences of incarcerated women who have perpetrated intimate partner homicide (IPH) and had been exposed to intimate partner violence (IPV) in their relationships. The study further explores women’s experiences of IPV, in particular those which motivated them to perpetrate IPH. The study examines how factors associated with IPV affect women to the point of responding with such lethal IPH. Additionally, it explores whether or not women feel remorse for their actions of IPH. The current study falls within an interpretive research paradigm and employs interpretative phenomenological analysis (IPA) as its theoretical framework. The researcher selected IPA as it works well in understanding and describing participants’ experiences. Semi-structured face to face interviews were conducted with nine women incarcerated for IPH. The findings of the study were analysed using the IPA approach. Three main themes emerged from the analysis: mainly all women reported to have experienced IPV in their respective relationships with the deceased, all, except one woman, reported that their partners had committed infidelity, the women also reported to have experienced much disappointment in gaining assistance from the judicial system. Therefore, on-going IPV including death threats resulted in fear; infidelity resulted in tremendous emotional and psychological strain, as well as feelings of betrayal; and perceived lack of support from the judicial system all appeared to have motivated women to perpetrate IPH with the majority indicating remorse.
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- Date Issued: 2015
An exploration of the principle of Dance Movement Therapy in water resource management research practice:
- Authors: Copteros, Athina
- Date: 2015
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/142016 , vital:38024 , ISBN PECS Conference: Social-ecological dynamics in the Anthropocene, Spier Estate, Cape Town, 2-5 November , http://www.pecs-science.org/research/news/news/2015pecsconferencesocialecologicaldynamicsintheanthropocene.5.40768cbb14b32a0480b694.html
- Description: An exploration of the principle of Dance Movement Therapy in water resource management research practice
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- Date Issued: 2015
Environmental flows, health and importance of macrophytes in the estuaries of water management area 11
- Authors: Cowie, Meredith
- Date: 2015
- Subjects: Estuarine ecology -- South Africa , Estuaries -- South Africa -- Management , Aquatic plants -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/7930 , vital:24324
- Description: Estuaries require sufficient quantity, quality and appropriate timing of freshwater inflow, referred to as environmental flow requirements, to ensure adequate health and functioning. In South Africa the environmental flow requirements of estuaries is determined using Resource Directed Measures (RDM). The present health and importance of an estuary must be considered when determining the ecological flow required to maintain an estuary in its desired state. An Estuarine Health Index that quantifies changes in abiotic and biotic components from natural conditions to present day is used. Health of biotic components is assessed according to changes in species richness, abundance and community composition. There has, however, been debate regarding the calculation of these attributes. In particular, for macrophytes, the inclusion of all habitat within the Estuarine Functional Zone (i.e. 5 m topographical contour) would affect the health and changes over time determined in past assessments. This is due to different areas being included as different areas would be included The aim of this study was to test the validity and suggest improvements to South Africa’s RDM macrophyte health score determination. The health of macrophytes were assessed at varying levels of intensity from desktop studies to thorough field studies. Rapid field studies provided a visual estimate of macrophyte health; while the intermediate and comprehensive assessments quantified change by mapping the distribution of macrophyte habitats from aerial photographs. These approaches were applied to the 64 estuaries within the Mvoti-Mzimkulu Water Management Area (WMA 11), situated in KwaZulu-Natal (KZN) on the subtropical east coast. Historically, these estuaries have supported restricted macrophyte habitats. Consequently, estuaries that presently or historically supported range limited habitats such as mangroves and swamp forest are considered important. Submerged macrophytes are scarce in KZN estuaries due to siltation and low turbidity and thus estuaries supporting this macrophyte habitat are also important. Based on available literature important estuaries were highlighted and selected for field studies. Transects spanning from the estuary water channel to the boundary of the EFZ provided a generalised distribution of KZN vegetation along an elevation gradient. The transition from estuarine to terrestrial vegetation can be used to improve the current EFZ boundaries, as estuarine area has been found to occur outside of the 5 m contour in some estuaries. Results from the desktop assessment indicated that most of the estuaries are moderately modified. There was a 50 % similarity in the macrophyte health scores determined by the desktop assessment to the 2011 National Biodiversity Assessment (NBA). Field studies mostly confirmed the desktop assessment aside from seven estuaries that had different scores. There has been a significant loss of macrophyte habitat with 100% loss of certain habitats from 9 of the 22 estuaries for which there were field assessments. Submerged macrophytes were not found at any of the estuaries that were assessed in the field. Black mangroves, Bruguiera gymnorrhiza (L.) Lam., were rediscovered at Ngane Estuary, however the few individuals could not be considered a ‘mappable’ community (i.e. <0.5 ha). Mtamvuna and Mkomazi estuaries both supported small stands of mangroves that, compared to data from 2006, appeared healthy. Macrophyte habitats and surrounding coastal forest matched the species composition described in the Vegetation Map of South Africa. The freshwater mangrove or Powder puff tree, Barringtonia racemosa (L.) Roxb, was not abundant in the estuaries. It was only found at four (Damba, Fafa, Little Amanzimtoti and Mvoti) of the estuaries that were assessed in the field. Important estuaries, from a botanical perspective, included some of the larger estuaries such as Mgeni, Durban Bay and Sipingo. Smaller, healthier estuaries that presently support mangrove and swamp forest habitat were also identified as important from a botanical perspective. Macrophyte habitats have mainly been lost due to non-flow related pressures. Sugarcane cultivation occurred within the floodplain of 25% of the estuaries. Nutrient enrichment was evident for 12.5% of the estuaries and reed encroachment was evident for 27% of estuaries for which there were field assessments. Development, aside from the N2 road bridges, was evident for 40% of the estuaries assessed in the field. Invasive plant species, including aquatic invasive plants, were present in all estuaries assessed in the field. The extent of invasive plant species was related to the degree of disturbance and surrounding land use pressures. The Mkomazi and Mvoti estuaries that were assessed at a comprehensive level, as they have earmarked for further water abstraction, had the poorest macrophyte health scores. The macrophyte health of these estuaries was much lower than previously determined by the NBA. The decline in health was attributed to the removal of macrophyte habitat for sugarcane cultivation and development as well as displacement by invasive plant species. The areas covered by the macrophyte habitats also differed from the NBA highlighting the importance of updated mapping and ground truthing. Largely differing macrophyte health scores were produced when attributes were calculated using different combinations of macrophyte habitats. Results indicate that only macrophyte habitats and no other floodplain vegetation should be included when calculating abundance. All macrophyte habitats, physical habitats and floodplain should be incorporated when calculating community composition. The minimum of these attributes is used as the overall macrophyte health score as a precautionary approach is followed. Scoring of health is subjective and the only benchmark for determining the most appropriate method is comparion with previous RDM studies. This study illustrates the need for a standardised RDM scoring method that is presented in a manner that ensures the same results irregardless of the speciliast conducting the study. The updated estuary health and importance scores for WMA 11 are necessary to inform management, particularly as few of the estuaries receive formal protection. In conclusion, this study contributed to the limited knowledge of the estuaries of WMA 11 and assisted in determining appropriate methods for assessing the health and importance of estuary macrophytes.
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- Date Issued: 2015
Developing and using an assessment instrument for spatial skills in Grade 10 geometry learners
- Authors: Cowley, Jane
- Date: 2015
- Subjects: Geometry -- Study and teaching (Secondary) -- South Africa -- Eastern Cape , Geometry -- Evaluation. , Mathematics -- Study and teaching (Secondary)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:2025 , http://hdl.handle.net/10962/d1017336
- Description: This qualitative investigation took the form of a case study and fell within the interpretive research paradigm. The Mathematics Chair at the Education Department of Rhodes University launched the Mathematics Teacher Enrichment Programme (MTEP) in 2010 in order to combat poor Mathematics performance of learners in the lower Albany district of the Eastern Cape. The challenge that the participating MTEP teachers faced was a lack of time available to implement new teaching ideas. This was because most of their time was spent catching up “lost” or untaught concepts in the classroom. To address this problem, the Catch-Up Project was launched, whereby selected Mathematics teachers in the area taught lost concepts to Grade Ten learners during afternoon classes in an attempt to improve their fundamental Mathematics knowledge. In order to establish which sections of Mathematics were more difficult for the learners in this programme, bench mark tests were administered biannually. Whilst these tests certainly identified deficient areas within their Mathematics knowledge, the poorest performance areas were the sections of the syllabus which were spatial in nature, such as Space and Shape and Geometry. However, a more in depth assessment tool was required to establish which specific spatial skills the learners were not able to employ when doing these Geometry tasks. To this end, the Spatial Skills Assessment Tasks (SSAT) was developed. It consisted of traditional text book type Geometry tasks and real-world context tasks, both of which were used to assess six spatial skills deemed crucial to successfully facilitate learning Geometry. The case study took place in two of the schools which participated in the Grade Ten Catch-Up project. The case was focused on Grade Ten learners and the unit of analysis was their responses to the SSAT instrument. The learners that participated all did so on a strictly voluntary basis and great care was taken to protect their wellbeing and anonymity at all times. The results of the SSAT instrument revealed that the real world context tasks were in general far more successfully answered than the traditional text book type questions. Important trends in learner responses were noted and highlighted. For example, geometric terminology remains a huge challenge for learners, especially as they study Mathematics in their second language. The ability of the learners to differentiate between such concepts as congruency and similarity is severely compromised, partly due to a lack of terminological understanding but also due to a perceived lack of exposure to the material. Concepts such as verticality and horizontality also remain a huge challenge, possibly for the same reasons. They are poorly understood and yet vital to achievement in Geometry. Recommendations for the development and strengthening of spatial skills support the constructivist approach to learning. Hands on activities and intensive sustained practice over a period of a few months, in which both teachers and learners are actively involved in the learning process, would be considered most beneficial to the long term enhancement of these vital spatial skills and to the learning of Geometry in general.
- Full Text:
- Date Issued: 2015
Saving the Sowetan : the public interest and commercial imperatives in journalism practice
- Authors: Cowling, Lesley
- Date: 2015
- Subjects: Sowetan (Johannesburg, South Africa) , Journalism -- Economic aspects -- South Africa -- Soweto , Journalism -- Political aspects -- South Africa -- Soweto , Black newspapers -- South Africa -- Soweto , Public interest -- South Africa -- Soweto , Corporate culture -- South Africa -- Soweto , Journalistic ethics -- South Africa -- Soweto , Journalism -- Objectivity -- South Africa -- Soweto
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3540 , http://hdl.handle.net/10962/d1017781
- Description: This thesis examines the complex ways in which notions of the public interest and commercial imperatives intertwine in journalism practice. It does this through a study of the 2004 takeover and relaunch of the Sowetan newspaper, the highest circulation daily in South Africa throughout the 1990s and an institution of black public life. The ‘public interest’ and ‘the commercial’ are recurring ideas in journalism scholarship and practice, and the relaunch appeared to be a challenge to reconcile the Sowetan’s commercial challenges with its historical responsibility to a ‘nation-building’ public. However, the research shows that the public/commercial aspects of journalism were inextricably entangled with Sowetan’s organisational culture, which was the matrix through which its journalism practice was expressed. Conflict in the organisation over the changes was not simply a contest between commercial realities and the public interest, with journalists defending a responsibility to the public and managers pushing commercial solutions, but a conflict between the culture of Sowetan “insiders”, steeped in the legacy of the newspaper, and “outsiders”, employed by the new owners to effect change. Another conclusion of the research is that commercial “realities” – often conceptualised as counter to the public interest – are highly mutable. Basic conditions, such as a dependence on advertising, exist. However, media managers must choose from a range of strategies to be commercially viable, which requires risk-taking, innovation and, often, guesswork. In such situations, the ‘wall’ between media managers and senior editors is porous, as all executives must manage the relationship between business and editorial imperatives. Executives tend to overlook culture as a factor in changing organisations, but I argue that journalism could benefit from engaging with management theory and organisational psychology, which offer ways to understand the specific dynamics of the organisation. Finally, I argue that the case of the Sowetan throws into question the idea that there may be a broadly universal journalism culture. The attachment of Sowetan journalists to their particular values and practice suggests that forms of journalism evolve in certain contexts to diverge from the ‘professional’ Anglo-American modes. These ‘journalisms’ use similar terms – such as the ‘public interest’ – but operationalise them quite differently. The responsibility to the public is imagined in very different ways, but remains a significant attachment for journalists.
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- Date Issued: 2015
Development role players' knowledge of ecological infrastructure in Eden district, South Africa
- Authors: Crisp, Abigail Gilmour
- Date: 2015
- Subjects: Climatic changes -- South Africa , Environmental management , Coastal engineering
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/8725 , vital:26424
- Description: Coastal disasters have been increasing in intensity and frequency around the world causing loss of life and millions of Rands’ worth of damage to infrastructure. Coastal communities are growing as more people are drawn to urban areas. These people depend on the services the coastal ecosystem provide but through degradation and land use change the supply of services is reduced. The ability of these communities and landscapes to bounce back from disturbance has been severely hampered. As a result communities are looking for ways in which they can protect their lives and their assets and become more resilient. Through development planning structures such as coastal foredunes, that offer a buffering capacity against storm surges, can be used to strengthen the resilience of coastal communities. The type of defences used in communities would be dependent on the knowledge of the decision makers. This study explores the discourses and practices that are present in development processes regarding ecological infrastructure (in its buffering capacity for risk reduction) as an option for adaptation to global environmental change in the coastal areas of Eden District. Qualitative data collection and analysis techniques were used. In-depth interviews were used to collect data, which was transformed into frequency data using content analysis. Descriptive statistics was then applied to the coded frequencies. The interpretation of the data was presented alongside the frequency data, via the descriptive statistics and quotations from interviews. It was determined that role players in development processes are aware of the complexities surrounding coastal social-ecological systems and understand the role foredunes play as ecological infrastructure within this system. Those who lack knowledge are aware of their knowledge gaps. Participants believe the study area is at risk due to human impacts and overall, participants felt that there is a general lack of awareness with regard to issues affecting our coastline, compounded by the absence of an enabling environment brought about by a lack of finances and time.
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- Date Issued: 2015
Characterisation of performance limiting defects in photovoltaic devices using electroluminescence and related techniques
- Authors: Crozier, Jacqueline Louise
- Date: 2015
- Subjects: Photovoltaic cells Solar cells Photovoltaic power systems
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/11004 , vital:26866
- Description: Solar cells allow the energy from the sun to be converted into electrical energy; this makes solar energy an environmentally friendly, sustainable alternative to fossil fuel energy sources. Solar cells are connected together in a photovoltaic (PV) module to provide the higher current, voltage and power outputs necessary for electrical applications. However, the performance of PV modules can limited by the degradation and defects. PV modules can be characterised using various opto-electronic techniques, each providing information about the performance of the module. The current-voltage (I-V) characteristic curve of a module being the most commonly used characterisation technique. The I-V curve is typically measured in outdoor, fully illuminated, conditions. This allows performance parameters such as short circuit current (ISC), open circuit voltage (VOC) and maximum power (PMAX) to be determined. However, it can be difficult to determine the root cause of the performance drop from the I-V curve alone. Electroluminescence (EL) is a module characterisation technique that allows defects and failures in PV modules to be successfully identified. This study investigates the characterisation of solar cells and photovoltaic modules using EL. EL occurs when a solar cell or module is forward biased and the injected electron-hole pairs recombine radiatively. The intensity of the emitted EL is related the applied voltage and the material properties. EL imaging is a useful characterisation technique in identifying module defects and failures. Defects such as micro-cracks, broken contact fingers and fractures are detected in EL images as well as material features such as grain boundaries. The common defects in crystalline silicon are catalogued and the possible causes are discussed. An experimental setup was developed in order to systematically take a high resolution EL image of every cell in the module and record the applied voltage and current. This produces a very detailed, clear, image of each cell with a pixel size in the micrometre range. This process is time consuming to acquire an EL image of an entire module so alternatively a different setup can be used and an EL image of a whole module can be captured in a single frame with an increased pixel size in the millimetre range. For EL imaging a silicon charge-coupled device (CCD) camera was used because it has very good spatial resolution however this sensor is only sensitive to wavelength in the range of 300-1200 nm. There is an overlap in wavelengths from about 900 to 1100 nm allowing the EL emitted from silicon solar cells to be detected. In conjunction with the high-resolution EL system an image processing program was developed to crop, adjust and align the images so only the relevant cell was included. This program also automatically detects certain defects that have a regular shape. Micro-cracks, broken fingers and striation rings are automatically identified. The program has an adjustable sensitivity to identify small or large defects. Defective cells are distinguished from undamaged cells by comparing the binary images to the ideal, undamaged cell. The current-voltage curves and the performance parameters of modules were compared with the EL images in order to discuss and identify power limiting defects. Features that remove significant portions of the cell from electrical contact such as micro-cracks are shown to have a larger effect of the performance of the module. Other features such as broken contact fingers, contact forming failures and striation rings do not significantly lower the performance of the module. Thus an understanding of how different features affect the module performance is important in order to correctly interpret the EL results. The intensity of the luminescence emitted is related to the applied voltage and the quantum efficiency of the cell material. The spectrum of the emitted luminescence was modelled and related to the recombination properties of the cell such as surface recombination velocity and minority carrier diffusion length/lifetime. In this study the emitted spectrum was modelled and the effects of recombination properties of the cell on the emitted spectrum were examined. The spectrum of the detected EL was modelled, dependent on the sensitivity of the camera, the transmission of the filters and the emitted photon flux. The integration of short-pass filters into the experimental setup in order to isolate short-wavelength luminescence was discussed. There is a proportional relationship between the intensity of the emitted EL and the local junction voltage. Resistive losses like series and shunt resistances lower the applied voltage and thus affect the EL image. The voltage dependence was assessed by comparing EL images taken at different applied biases. Analysis of the variation in EL intensity with voltage was successful in determining the origin of certain features in an EL image. Certain defects, those that are related to series resistance or shunting are highly voltage dependent. When a feature has little or no dependence on voltage then the defect could be in the laminate layers and not in the cell material. The results of this study allow for in-depth analysis of the defects found in PV modules using the high resolution EL imaging system and the image processing routine. The development of an image processing routine allows the interpretation of the EL image to be done automatically, resulting in a faster and more efficient process. By understanding the defects visible in the EL image, the test is more meaningful and allows the results to be used to predict module performance and potential failures.
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- Date Issued: 2015
Perceptions on the use of social media in the banking industry
- Authors: Cupp, Nicole Leshaan
- Date: 2015
- Subjects: Banks and banking -- Customer services , Banks and banking -- Social aspects , Internet marketing -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10948/5489 , vital:20870
- Description: As banks operate in a competitive environment, it is important for managers and marketers to identify how customer satisfaction and customer retention levels can be can be improved through social media aspects. Although models of customer satisfaction and customer retention have been well researched for client products/services, the literature available on social media as a marketing tool is limited in quantity compared to other more established areas of marketing. This research study reviews existing literature on the banking industry in terms of its characteristics and challenges. Literature on customer satisfaction and customer retention as relevant to the banking industry is reviewed, as well as how social media aspects can improve customer satisfaction and customer retention. Thus the primary objective of this study is to identify the social media aspects (benefits, clients’ trust and content) that influence the intervening variable (customer satisfaction) and dependent variable (customer retention) in the banking industry. An empirical investigation was undertaken to establish whether the independent variables; namely benefits, clients’ trust and content as related to social media can possibly influence customer satisfaction and ultimately customer retention in the banking industry. A positivistic research paradigm was followed for this study. Quantitative data was gathered by distributing questionnaires to a sample of bank clients and managers. The sample size consisted of 150 bank clients and 30 bank managers in the Nelson Mandela Metropolitan area in South Africa. The questionnaires were statistically analysed using the computer programmes Microsoft Excel and Statistica Version 12.0. The validity of the study was measured by utilising Exploratory Factor analysis. Cronbach’s Alpha correlation coefficients were calculated to measure the reliability and internal consistency of the measurement instrument of this study. Data was analysed in four phases. Descriptive statistics concerning the respondents and variables were calculated for this study. The validity of the measuring instrument was tested by performing EFA to consider construct validity. Thereafter, the internal reliability of the data was assessed using Cronbach’s Alpha correlation coefficients. Pearson’s product-moment correlation coefficients and multiple regression analyses were calculated. Through multiple regression calculations, the relationships predicted by the four hypotheses were analysed. Finally, t-tests and analysis of variance (ANOVA) tests were conducted. The empirical investigation revealed that significant positive relationships exist between the independent variables benefits, trustworthy content and the intervening variable customer satisfaction, as well as between these two independent variables and the dependent variable customer retention. From the empirical results it was concluded that if banks offer benefits and trustworthy content to their clients through social media channels, clients are likely to be satisfied with and retained by their bank. This study established and confirmed the significant positive relationship that exists between customer satisfaction and customer retention in the banking industry. All bank managers and marketers will benefit from the empirical results as well as the recommendations of this study on how to improve customer satisfaction and customer retention through social media channels which will ultimately improve the performance of banks.
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- Date Issued: 2015
Text data analysis for a smart city project in a developing nation
- Authors: Currin, Aubrey Jason
- Date: 2015
- Subjects: Natural language processing (Computer science) Human computation Human-computer interaction
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10353/2227 , vital:27709
- Description: Increased urbanisation against the backdrop of limited resources is complicating city planning and management of functions including public safety. The smart city concept can help, but most previous smart city systems have focused on utilising automated sensors and analysing quantitative data. In developing nations, using the ubiquitous mobile phone as an enabler for crowdsourcing of qualitative public safety reports, from the public, is a more viable option due to limited resources and infrastructure limitations. However, there is no specific best method for the analysis of qualitative text reports for a smart city in a developing nation. The aim of this study, therefore, is the development of a model for enabling the analysis of unstructured natural language text for use in a public safety smart city project. Following the guidelines of the design science paradigm, the resulting model was developed through the inductive review of related literature, assessed and refined by observations of a crowdsourcing prototype and conversational analysis with industry experts and academics. The content analysis technique was applied to the public safety reports obtained from the prototype via computer assisted qualitative data analysis software. This has resulted in the development of a hierarchical ontology which forms an additional output of this research project. Thus, this study has shown how municipalities or local government can use CAQDAS and content analysis techniques to prepare large quantities of text data for use in a smart city.
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- Date Issued: 2015
Challenges faced by Teachers in applying reading strategies when teaching English reading in the foundation phase in the Mthatha District
- Authors: Cweba, Vuyokazi
- Date: 2015
- Subjects: Reading(Foundation phase) English language -- Study and teaching -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , D Ed
- Identifier: http://hdl.handle.net/11260/856 , vital:29938
- Description: This study sought to investigate challenges faced by teachers in applying reading strategies when teaching reading in the Foundation Phase in the Mthatha District in South Africa. The study was conducted at Four Junior Secondary Schools. It was prompted by a deep concern about challenges faced by teachers in applying reading strategies required in the Foundation Phase. While studies have been carried out on applying reading strategies in the Foundation Phase, few studies have looked at the factors impacting on reading in South African schools, especially in the Mthatha District where isiXhosa is the mother tongue. The method used in this study involved a qualitative approach. The study addressed the following research questions: What strategies are used in the Foundation Phase? What type of challenges are faced by teachers? To what extent are educators trained to teach reading in the Foundation Phase? Does the lack of resources affect the performance of learners? To what extent does the use of a second language affect the performance of Foundation Phase learners? Do teachers receive enough support from the Department of Education to teach reading? The study is a multiple-case study and data were collected through individual interviews and focus group interviews (sixteen teachers were interviewed). Content analysis guided the data analysis through themes derived from the subsidiary questions. Data reporting took the form of thick description and verbatim quotations in line with the qualitative approach of the study. A pilot study was conducted in two Junior Secondary Schools for the purpose of validity and reliability. ii The study`s findings revealed that: Different reading strategies were used by teachers in the Foundation Phase, teachers faced many challenges in applying reading strategies such as teacher training in the teaching of reading. This suggests that intervention is needed by the Department of Education such as providing relevant resources which are essential in order to address the problem of reading. Improvisation by teachers to improve reading material, insufficient allocation of time, multilingualism, teacher competence, lack of motivation and parental involvement in relation to learner performance in reading all need attention in order to solve problems. Furthermore, lack of resources hinders the reading ability of learners. The use of home language as a medium of instruction in teaching reading is highlighted. There is insufficient support by the Department of Education for Foundation Phase teachers to teach reading. Based on the study findings, the researcher has recommended that teachers should be urged to use reading strategies in a way that benefits learners. The use of reading strategies, therefore, needs more attention. Libraries should be built in these schools to enable learners to develop a culture of reading. Education development officers, subject advisors, lead teachers and parents should work together to improve the reading ability of Foundation Phase learners.
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- Date Issued: 2015
The effects of gold coated and uncoated zinc oxide nanohexagons on the photophysicochemical properties of the low symmetry zinc phthalocyanine
- Authors: D'Souza, Sarah , Ogbodu, Rachael , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189077 , vital:44814 , xlink:href="https://doi.org/10.1016/j.molstruc.2015.06.088"
- Description: A new low symmetry, Zn phthalocyanine monosubstituted with diethylaminoethanethiol (mDEAET ZnPc) was synthesized and characterized. This work reports on its photophysical and photochemical properties of mDEAET ZnPc alone and when conjugated to gold coated and uncoated zinc oxide nanohexagons (ZnO NHXs). The photophysicochemical properties generally improved in the presence of the ZnO NHXs. These complexes were also tested for their photodynamic antimicrobial activity against Staphylococcus aureus (S. aureus). The Pc alone showed remarkable growth inhibition even at concentrations as low as 0.05 mg/mL. The conjugates showed a high photoinactivation of S. aureus after 30 min at a fluence of 90 mW cm−2 at a concentration of 0.05 mg/mL. The ZnPc-ZnO NHX conjugates produced the best antimicrobial results.
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- Date Issued: 2015
Enhanced triplet state yields in aqueous media of asymmetric zinc phthalocyanines when conjugated to silver nanoflowers
- Authors: D'Souza, Sarah , George, Reama , Göksel, Meltem , Atilla, Devrim , Durmus, Mahmut , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189099 , vital:44816 , xlink:href="https://doi.org/10.1016/j.poly.2015.08.017"
- Description: Novel low symmetry water-soluble zinc phthalocyanines (ZnPcs, complexes 1 and 2) were synthesized and then mixed with silver nanoflowers. Photophysical and photochemical studies were performed in order to determine the efficiency of complexes 1 and 2 as photosensitizers when alone and when combined with the silver nanoflowers. The Pcs show low fluorescence quantum yields and excellent triplet quantum yields of 0.78 (for 1) and 0.66 (for 2) in aqueous media. The triplet quantum yield values increased to 0.80 and 0.89, respectively, in the presence of silver nanoflowers. Long triplet lifetimes ranging from 180 to 200 μs in DMSO were obtained for complexes 1, 2 and their conjugates with silver nanoflowers.
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- Date Issued: 2015
Effects of differently shaped silver nanoparticles on the photophysics of pyridylsulfanyl-substituted phthalocyanines
- Authors: D'Souza, Sarah , Mashazi, Philani N , Britton, Jonathan , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193564 , vital:45348 , xlink:href="https://doi.org/10.1016/j.poly.2015.06.038"
- Description: This paper reports on the photophysical behavior of (2-pyridylsulfanyl)phthalocyaninato zinc(II) and 2,9(10),16(17),23(24)-tetra-(2-pyridylsulfanyl)phthalocyaninato zinc(II) in the presence of differently shaped silver nanoparticles (nanospheres, nanotriangles and nanoflowers). The presence of shaped nanoparticles increased both triplet quantum yields and lifetimes of the tetra-substituted mercaptopyridine zinc phthalocyanine in DMSO. It is apparent from this work that the shape of the silver nanoparticle used is of little consequence in influencing photophysical behavior of the phthalocyanines.
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- Date Issued: 2015
Effects of ZnO nanohexagons and nanorods on the fluorescence behavior of metallophthalocyanines
- Authors: D'Souza, Sarah , Moeno, Sharon , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189741 , vital:44927 , xlink:href="https://doi.org/10.1016/j.poly.2014.09.012"
- Description: This paper looks at the fluorescence behavior of zinc phthalocyanines: 2,(3),9(10),16(17),23(24)-tetrakis- (mercaptoacetic acid phthalocyaninato) zinc(II) (ZnTMAAPc), 2,(3),9(10),16(17),23(24)-tetrakis-(mercaptopropanoic acid phthalocyaninato) zinc(II) (ZnTMPAPc) and (OH)AlPcSmix (the latter contains a mixture of the di-, tri- and tetra-sulfonated derivatives with an average of three sulfonated groups per molecule) in the presence of ZnO nanoparticles. Fluorescence lifetimes of Pc complexes generally decreased in the presence of ZnO nanoparticles, with generally longer lifetimes for ZnO nanohexagons compared to ZnO nanorods.
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- Date Issued: 2015