Cyber Security Responsibilization: an evaluation of the intervention approaches adopted by the Five Eyes Countries and China
- Renaud, Karen, Orgeron, Craig, Warkentin, Merrill, French, P Edward
- Authors: Renaud, Karen , Orgeron, Craig , Warkentin, Merrill , French, P Edward
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149806 , vital:38885 , https://0-doi.org.wam.seals.ac.za/10.1111/puar.13210
- Description: Governments can intervene to a greater or lesser extent in managing the risks that citizens face. They can adopt a maximal intervention approach (e .g. COVID‐19) or a hands‐off approach (e .g ., unemployment) , effectively “responsibilizing” their citizens. To manage the cyber risk, governments publish cyber‐related policies. This article examines the intervention stances the governments adopt in supporting individual citizens managing their personal cyber risk. The authors pinpoint the cyber‐related responsibilities that several governments espouse, applying a “responsibilization” analysis. Those applying to citizens are identified, thereby revealing the governments' cyber‐related intervention stance. The analysis reveals that most governments adopt a minimal cyber‐related intervention stance in supporting their citizens. Given the increasing number of successful cyber attacks on individuals, it seems time for the consequences of this stance to be acknowledged and reconsidered. The authors argue that governments should support individual citizens more effectively in dealing with cyber threats.
- Full Text:
- Date Issued: 2020
- Authors: Renaud, Karen , Orgeron, Craig , Warkentin, Merrill , French, P Edward
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149806 , vital:38885 , https://0-doi.org.wam.seals.ac.za/10.1111/puar.13210
- Description: Governments can intervene to a greater or lesser extent in managing the risks that citizens face. They can adopt a maximal intervention approach (e .g. COVID‐19) or a hands‐off approach (e .g ., unemployment) , effectively “responsibilizing” their citizens. To manage the cyber risk, governments publish cyber‐related policies. This article examines the intervention stances the governments adopt in supporting individual citizens managing their personal cyber risk. The authors pinpoint the cyber‐related responsibilities that several governments espouse, applying a “responsibilization” analysis. Those applying to citizens are identified, thereby revealing the governments' cyber‐related intervention stance. The analysis reveals that most governments adopt a minimal cyber‐related intervention stance in supporting their citizens. Given the increasing number of successful cyber attacks on individuals, it seems time for the consequences of this stance to be acknowledged and reconsidered. The authors argue that governments should support individual citizens more effectively in dealing with cyber threats.
- Full Text:
- Date Issued: 2020
Cyclooxygenase-1 as an anti-stroke target: potential inhibitor identification and non-synonymous single nucleotide polymorphism analysis
- Authors: Muronzi, Tendai
- Date: 2020
- Subjects: Cerebrovascular disease , Cerebrovascular disease -- Treatment , Cerebrovascular disease -- Chemotherapy , Cyclooxygenases , High throughput screening (Drug development) , Drug development , Molecular dynamics , South African Natural Compounds Database , ZINC database
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/143404 , vital:38243
- Description: Stroke is the third leading cause of death worldwide, with 87% of cases being ischemic stroke. The two primary therapeutic strategies to reduce post-ischemic brain damage are cellular and vascular approaches. The vascular strategy aims to rapidly re-open obstructed blood vessels, while the cellular approach aims to interfere with the signalling pathways that facilitate neuron damage and death. Unfortunately, popular vascular treatments have adverse side effects, necessitating the need for alternative chemotherapeutics. In this study, cyclooxygenase-1 (COX-1), which plays a significant role in the post- ischemic neuroinflammation and neuronal death, was targeted for identification of novel drug compounds and to assess the effect of nsSNPs on its structure and function. In a drug discovery part, ligands from the South African Natural Compounds Database (SANCDB-https://sancdb.rubi.ru.ac.za/) and ZINC database (http://zinc15.docking.org/) were used for high-throughput virtual screening (HVTS) against COX-1. Additionally, five nsSNPs were being investigated to assess their impact on protein structure and function. Three of these SNPs were in the COX-1 dimer interface. Molecular docking and molecular dynamics simulations revealed asymmetric nature of the protein. Several ligands, peculiar to each monomer, exhibited favourable binding energies in the respective active sites. SNP analysis indicated effects on inter-monomer interactions and protein stability.
- Full Text:
- Date Issued: 2020
- Authors: Muronzi, Tendai
- Date: 2020
- Subjects: Cerebrovascular disease , Cerebrovascular disease -- Treatment , Cerebrovascular disease -- Chemotherapy , Cyclooxygenases , High throughput screening (Drug development) , Drug development , Molecular dynamics , South African Natural Compounds Database , ZINC database
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/143404 , vital:38243
- Description: Stroke is the third leading cause of death worldwide, with 87% of cases being ischemic stroke. The two primary therapeutic strategies to reduce post-ischemic brain damage are cellular and vascular approaches. The vascular strategy aims to rapidly re-open obstructed blood vessels, while the cellular approach aims to interfere with the signalling pathways that facilitate neuron damage and death. Unfortunately, popular vascular treatments have adverse side effects, necessitating the need for alternative chemotherapeutics. In this study, cyclooxygenase-1 (COX-1), which plays a significant role in the post- ischemic neuroinflammation and neuronal death, was targeted for identification of novel drug compounds and to assess the effect of nsSNPs on its structure and function. In a drug discovery part, ligands from the South African Natural Compounds Database (SANCDB-https://sancdb.rubi.ru.ac.za/) and ZINC database (http://zinc15.docking.org/) were used for high-throughput virtual screening (HVTS) against COX-1. Additionally, five nsSNPs were being investigated to assess their impact on protein structure and function. Three of these SNPs were in the COX-1 dimer interface. Molecular docking and molecular dynamics simulations revealed asymmetric nature of the protein. Several ligands, peculiar to each monomer, exhibited favourable binding energies in the respective active sites. SNP analysis indicated effects on inter-monomer interactions and protein stability.
- Full Text:
- Date Issued: 2020
Cytotoxicity of triterpenoids from Clerodendrum glabrum against triple negative breast cancer cells in vitro:
- Teclegeorgish, Zecarias W, Mokgalaka, Ntebogeng S, Vukea, Nyeleti, de la Mare, Jo-Anne, Tembu, Vuyelwa J
- Authors: Teclegeorgish, Zecarias W , Mokgalaka, Ntebogeng S , Vukea, Nyeleti , de la Mare, Jo-Anne , Tembu, Vuyelwa J
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/161511 , vital:40634 , https://doi.org/10.1016/j.sajb.2020.07.009
- Description: Clerodendrum glabrum is an indigenous medicinal plant that is used to treat cough, cold, sore throat and chest complaints. The stem bark of Clerodendrum glabrum afforded four tritepenoids namely, 3β-olean-12-en-3-yl palmitate (β-amyrin palmitate), (1), 3β hydroxy 5-glutinene (glutinol), (2), 3β-lup-20(29)-en-3-palmitate (Lupeol-3-palmitate), (3), 3β-lup-20(29)-en-3-ol (lupeol) (4) and one common phytosterol (stigmasterol) (5). The structures were established on the basis of their spectroscopic analysis. The compounds were screened for cytotoxicity against the HCC70 triple negative breast cancer (TNBC), MCF-7 hormone receptor positive breast cancer and MCF-12A non-cancerous mammary epithelial cell lines.
- Full Text:
- Date Issued: 2020
- Authors: Teclegeorgish, Zecarias W , Mokgalaka, Ntebogeng S , Vukea, Nyeleti , de la Mare, Jo-Anne , Tembu, Vuyelwa J
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/161511 , vital:40634 , https://doi.org/10.1016/j.sajb.2020.07.009
- Description: Clerodendrum glabrum is an indigenous medicinal plant that is used to treat cough, cold, sore throat and chest complaints. The stem bark of Clerodendrum glabrum afforded four tritepenoids namely, 3β-olean-12-en-3-yl palmitate (β-amyrin palmitate), (1), 3β hydroxy 5-glutinene (glutinol), (2), 3β-lup-20(29)-en-3-palmitate (Lupeol-3-palmitate), (3), 3β-lup-20(29)-en-3-ol (lupeol) (4) and one common phytosterol (stigmasterol) (5). The structures were established on the basis of their spectroscopic analysis. The compounds were screened for cytotoxicity against the HCC70 triple negative breast cancer (TNBC), MCF-7 hormone receptor positive breast cancer and MCF-12A non-cancerous mammary epithelial cell lines.
- Full Text:
- Date Issued: 2020
Data on microhardness and structural analysis of friction stir spot welded lap joints of AA5083-H116
- Esther T. Akinlabi, Ayuba S. Osinubi b, Nkosinathi Madushele b, Stephen A. Akinlabi c, Omolayo M. Ikumapayi d,∗
- Authors: Esther T. Akinlabi , Ayuba S. Osinubi b , Nkosinathi Madushele b , Stephen A. Akinlabi c , Omolayo M. Ikumapayi d,∗
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/3260 , vital:43286 , https://www.sciencedirect.com/science/article/pii/S2352340920314669
- Description: Friction stir spot welding (FSSW) was established to compete reasonably with the reverting, bolting, adhesive bonding as well as resistance spot welding (RSW) which have been used in the past for lap joining in automobile, aerospace, marine, railways, defence and shipbuilding industries. The use of these ancient and conventional joining techniques had led to increasing material cost, installation labour, and additional weight in the aircraft, shipbuilding, and other areas of applications. All these are disadvantages that can be overcome using FSSW. This research work carried out friction stir spot welding on 5058-H116 aluminium alloy by employing rotational speed in the step of 300 rpm ranges from 600 rpm to 1200 rpm with a no travel speed. It was noted that the dwell times were in the step of 5 s varying from 5 s to 15 s while the tool plunge rate was maintained at 30 mm/min. In this dataset, a cylindrical tapered rotating H13 Hot-working steel tool was used with a probe length of 5 mm and probe diameter of 6 mm, it has a shoulder diameter of 18 mm. The tool penetration depth (plunge) was maintained at 0.2 mm and the tool tilt angle at 2°. Structural integrity was car-ried out using Rigaku ultima IV multifunctional X-ray diffractometer (XRD) with a scan voltage of 40 kV and scan current of 30 mA. This was used to determine crystallite sizes, peak intensity, d-spacing, full width at half maximum intensity (FWHM) of the diffraction peak. TH713 digital microhardness equipment with diamond indenter was used for microhardness data acquisition following ASTM E92–82 standard test. The average Vickers hardness data values at different zones of the spot-welds were captured and presented.
- Full Text:
- Date Issued: 2020
Data on microhardness and structural analysis of friction stir spot welded lap joints of AA5083-H116
- Authors: Esther T. Akinlabi , Ayuba S. Osinubi b , Nkosinathi Madushele b , Stephen A. Akinlabi c , Omolayo M. Ikumapayi d,∗
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/3260 , vital:43286 , https://www.sciencedirect.com/science/article/pii/S2352340920314669
- Description: Friction stir spot welding (FSSW) was established to compete reasonably with the reverting, bolting, adhesive bonding as well as resistance spot welding (RSW) which have been used in the past for lap joining in automobile, aerospace, marine, railways, defence and shipbuilding industries. The use of these ancient and conventional joining techniques had led to increasing material cost, installation labour, and additional weight in the aircraft, shipbuilding, and other areas of applications. All these are disadvantages that can be overcome using FSSW. This research work carried out friction stir spot welding on 5058-H116 aluminium alloy by employing rotational speed in the step of 300 rpm ranges from 600 rpm to 1200 rpm with a no travel speed. It was noted that the dwell times were in the step of 5 s varying from 5 s to 15 s while the tool plunge rate was maintained at 30 mm/min. In this dataset, a cylindrical tapered rotating H13 Hot-working steel tool was used with a probe length of 5 mm and probe diameter of 6 mm, it has a shoulder diameter of 18 mm. The tool penetration depth (plunge) was maintained at 0.2 mm and the tool tilt angle at 2°. Structural integrity was car-ried out using Rigaku ultima IV multifunctional X-ray diffractometer (XRD) with a scan voltage of 40 kV and scan current of 30 mA. This was used to determine crystallite sizes, peak intensity, d-spacing, full width at half maximum intensity (FWHM) of the diffraction peak. TH713 digital microhardness equipment with diamond indenter was used for microhardness data acquisition following ASTM E92–82 standard test. The average Vickers hardness data values at different zones of the spot-welds were captured and presented.
- Full Text:
- Date Issued: 2020
Data transport over optical fibre for ska using advanced modulation flexible spectrum technology
- Authors: Dlamini, Phumla Patience
- Date: 2020
- Subjects: Fiber optics
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/50666 , vital:42329
- Description: Flexible Spectrum Dense Wavelength Division Multiplexed (DWDM) optical fibre networks are next-generation technology for handling extremely high data rates of the kind produced by MeerKAT and SKA.We optimise the flexible spectrum for real-time dynamic channel wavelength assignment, to ensure optimum network performance. We needed to identify and develop novel hardware and dynamic algorithms for these networks to function optimally to perform critical tasks. Such tasks include wavelength assignment, signal routing, network restoration and network protection. The antennas of the Square Kilometre Array (SKA) network connect to the correlator and data processor in a simple point-to-point fixed configuration. The connection of the astronomer users to the data processor, however, requires a more complex network architecture. This is because the network has users scattered around South Africa, Africa and the whole world. This calls for upgrade of the classical fixed wavelength spectrum grids, to flexible spectrum grid that has improved capacity, reliable, simple and cost-effectiveness through sharing of network infrastructure. The exponential growth of data traffic in current optical communication networks requires higher capacity for the bandwidth demands at a reduced cost per bit. All-optical signal processing is a promising technique to improve network resource utilisation and resolve wavelength contention associated with the flexible spectrum. Flexible Spectrum Dense Wavelength Division Multiplexed (DWDM) optical fibre networks are next-generation technology for handling extremely high data rates of the kind produced by MeerKAT and SKA. Each DWDM channel is capable of 10 Gbps transmission rate, which is sliceable into finer flexible grid 12.5 GHz granularity to offer the network elastic spectrum and channel spacing capable of signal routing and wavelength switching for the scalability of aggregate bandwidth. The variable-sized portions of the flexible spectrum assignment to end users at different speeds depend on bandwidth demand, allowing efficient utilisation of the spectrum resources. The entire bandwidth of dynamic optical connections must be contiguously allocated. However, there is an introduction of spectrum fragmentation due to spectrum contiguity related to the optical channels having different width. Thus large traffic demands are likely to experience blocking regardless of available bandwidth. To minimise the congestion and cost-effectively obtain high performance, the optical network must be reconfigurable, achievable by adding wavelength as an extra degree of freedom for effectiveness. This can introduce colourless, directionless and contentionless reconfigurability to route individual wavelengths from fibre to fibre across multiple nodes to avoid wavelength blocking/collisions, increasing the flexibility and capacity of a network. For these networks to function optimally, novel hardware and dynamic algorithms identification and development is a critical task. Such tasks include wavelength assignment, signal routing, network restoration and network protection. In this work, we for the first time to our knowledge proposed a spectrum defragmentation technique through reallocation of the central frequency of the optical transmitter, to increase the probability of finding a sufficient continuous spectrum. This is to improve network resource utilisation, capacity and resolve wavelength contention associated with a flexible spectrum in optical communication networks. The following chapter provides details on a flexible spectrum in optical fibre networks utilising DWDM, optimising transmitter-receivers, advanced modulation formats, coherent detection, reconfigurable optical add and drop multiplexer (ROADM) technology to implement hardware and middleware platforms which address growing bandwidth demands for scalability, flexibility and cost-efficiency. A major attribute is tunable lasers, an essential component for future flexible spectrum with application to wavelength switching, routing, wavelength conversion and ROADM for the multi-node optical network through spectrum flexibility and cost-effective sharing of fibre links, transmitters and receivers. Spectrum slicing into fine granular sub-carriers and assigning several frequency slots to accommodate diverse traffic demands is a viable approach. This work experimentally presents a spectral efficient technique for bandwidth variability, wavelength allocation, routing, defragmentation and wavelength selective switches in the nodes of a network, capable of removing the fixed grid spacing using low cost, high bandwidth, power-efficient and wavelength-tunable vertical-cavity surface-emitting laser (VCSEL) transmitter directly modulated with 10 Gbps data. This to ensure that majority of the spectrum utilisation at finer channel spacing, wastage of the spectrum resource as caused by the wavelength continuity constraint reduction and it improves bandwidth utilisation. The technique is flexible in terms of modulation formats and accommodates various formats with spectrally continuous channels, fulfilling the future bandwidth demands with transmissions beyond 100 Gbps per channel while maintaining spectral efficiency.
- Full Text:
- Date Issued: 2020
- Authors: Dlamini, Phumla Patience
- Date: 2020
- Subjects: Fiber optics
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/50666 , vital:42329
- Description: Flexible Spectrum Dense Wavelength Division Multiplexed (DWDM) optical fibre networks are next-generation technology for handling extremely high data rates of the kind produced by MeerKAT and SKA.We optimise the flexible spectrum for real-time dynamic channel wavelength assignment, to ensure optimum network performance. We needed to identify and develop novel hardware and dynamic algorithms for these networks to function optimally to perform critical tasks. Such tasks include wavelength assignment, signal routing, network restoration and network protection. The antennas of the Square Kilometre Array (SKA) network connect to the correlator and data processor in a simple point-to-point fixed configuration. The connection of the astronomer users to the data processor, however, requires a more complex network architecture. This is because the network has users scattered around South Africa, Africa and the whole world. This calls for upgrade of the classical fixed wavelength spectrum grids, to flexible spectrum grid that has improved capacity, reliable, simple and cost-effectiveness through sharing of network infrastructure. The exponential growth of data traffic in current optical communication networks requires higher capacity for the bandwidth demands at a reduced cost per bit. All-optical signal processing is a promising technique to improve network resource utilisation and resolve wavelength contention associated with the flexible spectrum. Flexible Spectrum Dense Wavelength Division Multiplexed (DWDM) optical fibre networks are next-generation technology for handling extremely high data rates of the kind produced by MeerKAT and SKA. Each DWDM channel is capable of 10 Gbps transmission rate, which is sliceable into finer flexible grid 12.5 GHz granularity to offer the network elastic spectrum and channel spacing capable of signal routing and wavelength switching for the scalability of aggregate bandwidth. The variable-sized portions of the flexible spectrum assignment to end users at different speeds depend on bandwidth demand, allowing efficient utilisation of the spectrum resources. The entire bandwidth of dynamic optical connections must be contiguously allocated. However, there is an introduction of spectrum fragmentation due to spectrum contiguity related to the optical channels having different width. Thus large traffic demands are likely to experience blocking regardless of available bandwidth. To minimise the congestion and cost-effectively obtain high performance, the optical network must be reconfigurable, achievable by adding wavelength as an extra degree of freedom for effectiveness. This can introduce colourless, directionless and contentionless reconfigurability to route individual wavelengths from fibre to fibre across multiple nodes to avoid wavelength blocking/collisions, increasing the flexibility and capacity of a network. For these networks to function optimally, novel hardware and dynamic algorithms identification and development is a critical task. Such tasks include wavelength assignment, signal routing, network restoration and network protection. In this work, we for the first time to our knowledge proposed a spectrum defragmentation technique through reallocation of the central frequency of the optical transmitter, to increase the probability of finding a sufficient continuous spectrum. This is to improve network resource utilisation, capacity and resolve wavelength contention associated with a flexible spectrum in optical communication networks. The following chapter provides details on a flexible spectrum in optical fibre networks utilising DWDM, optimising transmitter-receivers, advanced modulation formats, coherent detection, reconfigurable optical add and drop multiplexer (ROADM) technology to implement hardware and middleware platforms which address growing bandwidth demands for scalability, flexibility and cost-efficiency. A major attribute is tunable lasers, an essential component for future flexible spectrum with application to wavelength switching, routing, wavelength conversion and ROADM for the multi-node optical network through spectrum flexibility and cost-effective sharing of fibre links, transmitters and receivers. Spectrum slicing into fine granular sub-carriers and assigning several frequency slots to accommodate diverse traffic demands is a viable approach. This work experimentally presents a spectral efficient technique for bandwidth variability, wavelength allocation, routing, defragmentation and wavelength selective switches in the nodes of a network, capable of removing the fixed grid spacing using low cost, high bandwidth, power-efficient and wavelength-tunable vertical-cavity surface-emitting laser (VCSEL) transmitter directly modulated with 10 Gbps data. This to ensure that majority of the spectrum utilisation at finer channel spacing, wastage of the spectrum resource as caused by the wavelength continuity constraint reduction and it improves bandwidth utilisation. The technique is flexible in terms of modulation formats and accommodates various formats with spectrally continuous channels, fulfilling the future bandwidth demands with transmissions beyond 100 Gbps per channel while maintaining spectral efficiency.
- Full Text:
- Date Issued: 2020
Database and guide for Lesotho wool and mohair production and quality
- Authors: Maqalika, Papali Elizabeth
- Date: 2020
- Subjects: Mohair -- Dissertations -- Lesotho , Wool -- Dissertations -- Lesotho Textile fabrics -- Lesotho Textile industry -- Lesotho
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/49148 , vital:41605
- Description: Lesotho produces significant quantities of Merino apparel wool and mohair, both of a quality that allows them to compete on the global market and to make a significant contribution to the economy of the country. Nevertheless, very little production and quality data and trends of these fibres have been documented. This is a serious disadvantage in terms of international trading and benchmarking as well as attempts to improve the production and quality of Lesotho wool and mohair. In the light of the aforementioned, the available production and quality data of the past 10 years have been captured and analysed for trends and also benchmarking, where considered applicable. The main focus is on fibre diameter (fineness), staple length, and yield since they largely determine fibre quality, application and price. Some quality related tests were undertaken to fill certain important gaps in the available data. In addition, prickle and medullation were evaluated on representative wool and mohair samples, respectively, because they represent important quality measures for apparel wool and mohair, respectively. It was found that Lesotho wool and mohair are of a fairly good and internationally competitive quality, with the wool having an average fibre diameter (MFD) of ≈20μm, an average staple length of about 64mm, an average VM level of about 4%, an average yield of about 57%, and the annual production being about 4 million kilograms greasy. The average staple length of the mohair was about 140mm, average MFD about 29μm and the average medullation, which unless otherwise specified, refers to the objectionable medullated fibres (kemp type) including the flat medullated fibre, relatively high at about 5.7%. The latter is certainly an area of concern which needs attention and improvement. It was found that the prickle level (Comfort Factor), of some of the wools tested was of such a level as to make the wool suitable for wearing against the skin. With respect to mohair, there is considerable scope to substantially reduce the level of objectionable medullated (kemp style) fibre level through the appropriate breeding interventions. Production of both wool and mohair has increased slightly over the ten years covered by this study. It also became apparent that Lesotho wool and mohair quality and production are greatly influenced by the farming practices and climatic conditions. Greater adoption of the merino sheep breed, sheds/barns and sheep coats are suggested as ways to reduce mortality rate (due to extremely cold temperatures), improve quality and increase yield and production. Some farming practices such as the lack of barns, supplementary feeding and veterinary care present constraints in terms of production of both wool and mohair. The districts in the Highlands region had the highest production of mostly wool, this being ascribed to better pastures, climatic and other conditions conducive to wool and mohair production. Both wool and mohair are considered to have potential for improved quality and production, which could be affected by appropriate interventions by the Small Agricultural and Development Project (SADP) and others through National Wool and Mohair Growers Association (NWMGA). Nevertheless, since the wool and mohair growers (farmers) do not form part of these and other interventions, they do not readily adopt the various strategies and decisions and do not receive the associated benefits immediately. It is therefore advised that local farmers, relevant educators and researchers be represented in policy and other decision making forums. In this way, educational campaigns will be demand driven with greater chance of adoption and success.
- Full Text:
- Date Issued: 2020
- Authors: Maqalika, Papali Elizabeth
- Date: 2020
- Subjects: Mohair -- Dissertations -- Lesotho , Wool -- Dissertations -- Lesotho Textile fabrics -- Lesotho Textile industry -- Lesotho
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/49148 , vital:41605
- Description: Lesotho produces significant quantities of Merino apparel wool and mohair, both of a quality that allows them to compete on the global market and to make a significant contribution to the economy of the country. Nevertheless, very little production and quality data and trends of these fibres have been documented. This is a serious disadvantage in terms of international trading and benchmarking as well as attempts to improve the production and quality of Lesotho wool and mohair. In the light of the aforementioned, the available production and quality data of the past 10 years have been captured and analysed for trends and also benchmarking, where considered applicable. The main focus is on fibre diameter (fineness), staple length, and yield since they largely determine fibre quality, application and price. Some quality related tests were undertaken to fill certain important gaps in the available data. In addition, prickle and medullation were evaluated on representative wool and mohair samples, respectively, because they represent important quality measures for apparel wool and mohair, respectively. It was found that Lesotho wool and mohair are of a fairly good and internationally competitive quality, with the wool having an average fibre diameter (MFD) of ≈20μm, an average staple length of about 64mm, an average VM level of about 4%, an average yield of about 57%, and the annual production being about 4 million kilograms greasy. The average staple length of the mohair was about 140mm, average MFD about 29μm and the average medullation, which unless otherwise specified, refers to the objectionable medullated fibres (kemp type) including the flat medullated fibre, relatively high at about 5.7%. The latter is certainly an area of concern which needs attention and improvement. It was found that the prickle level (Comfort Factor), of some of the wools tested was of such a level as to make the wool suitable for wearing against the skin. With respect to mohair, there is considerable scope to substantially reduce the level of objectionable medullated (kemp style) fibre level through the appropriate breeding interventions. Production of both wool and mohair has increased slightly over the ten years covered by this study. It also became apparent that Lesotho wool and mohair quality and production are greatly influenced by the farming practices and climatic conditions. Greater adoption of the merino sheep breed, sheds/barns and sheep coats are suggested as ways to reduce mortality rate (due to extremely cold temperatures), improve quality and increase yield and production. Some farming practices such as the lack of barns, supplementary feeding and veterinary care present constraints in terms of production of both wool and mohair. The districts in the Highlands region had the highest production of mostly wool, this being ascribed to better pastures, climatic and other conditions conducive to wool and mohair production. Both wool and mohair are considered to have potential for improved quality and production, which could be affected by appropriate interventions by the Small Agricultural and Development Project (SADP) and others through National Wool and Mohair Growers Association (NWMGA). Nevertheless, since the wool and mohair growers (farmers) do not form part of these and other interventions, they do not readily adopt the various strategies and decisions and do not receive the associated benefits immediately. It is therefore advised that local farmers, relevant educators and researchers be represented in policy and other decision making forums. In this way, educational campaigns will be demand driven with greater chance of adoption and success.
- Full Text:
- Date Issued: 2020
Dataset and ANN model prediction of performance of graphene nanolubricant with R600a in domestic refrigerator system
- Taiwo, Babarinde, Stephen, Akinlabi, Daniel Makundwaneyi, Madyira, Ekundayo, Funmilayo M, Paul Adeola, Adedeji
- Authors: Taiwo, Babarinde , Stephen, Akinlabi , Daniel Makundwaneyi, Madyira , Ekundayo, Funmilayo M , Paul Adeola, Adedeji
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/3139 , vital:43150 , (https://www.sciencedirect.com/science/article/pii/S2352340920309926)
- Description: This work evaluated the steady state performance of R600a in the base lubricant and graphene nanolubricant. The measuring instruments required and their uncertainties were provided, step by step method and procedures for preparation of graphene nanolubricant concentration and substituting it with the base lubricant in domestic refrigerator system are described. The system temperatures data was captured at the inlet and outlet of the system components. Also, the pressures data was recorded at the compressor inlet and outlet. The data was recorded for 3 h at 30 min interval at an ambient temperature of 27 °C. The experimental dataset, Artificial Neural Network (ANN) training and testing dataset are provided. The artificial intelligence approach of ANN model to predict the performance of graphene nanolubricant in domestic refrigerator is explained. Also, the ANN model prediction statistical performance metrics such as Root Mean Square Error (RMSE) and Mean Absolute Deviation (MAD), Mean Absolute Percentage Error (MAPE) and coefficient of determination (R2) are also provided. The data is useful to researchers in the field of refrigeration and energy efficiency materials, for replacing nanolubricant with the base lubricant in refrigerator systems. The data can be reuse for simulation and modelling vapour compression energy system.
- Full Text:
- Date Issued: 2020
- Authors: Taiwo, Babarinde , Stephen, Akinlabi , Daniel Makundwaneyi, Madyira , Ekundayo, Funmilayo M , Paul Adeola, Adedeji
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/3139 , vital:43150 , (https://www.sciencedirect.com/science/article/pii/S2352340920309926)
- Description: This work evaluated the steady state performance of R600a in the base lubricant and graphene nanolubricant. The measuring instruments required and their uncertainties were provided, step by step method and procedures for preparation of graphene nanolubricant concentration and substituting it with the base lubricant in domestic refrigerator system are described. The system temperatures data was captured at the inlet and outlet of the system components. Also, the pressures data was recorded at the compressor inlet and outlet. The data was recorded for 3 h at 30 min interval at an ambient temperature of 27 °C. The experimental dataset, Artificial Neural Network (ANN) training and testing dataset are provided. The artificial intelligence approach of ANN model to predict the performance of graphene nanolubricant in domestic refrigerator is explained. Also, the ANN model prediction statistical performance metrics such as Root Mean Square Error (RMSE) and Mean Absolute Deviation (MAD), Mean Absolute Percentage Error (MAPE) and coefficient of determination (R2) are also provided. The data is useful to researchers in the field of refrigeration and energy efficiency materials, for replacing nanolubricant with the base lubricant in refrigerator systems. The data can be reuse for simulation and modelling vapour compression energy system.
- Full Text:
- Date Issued: 2020
Dataset of experimental and adaptive neuro-fuzzy inference system (ANFIS) model prediction of R600a/MWCNT nanolubricant in a vapour compression system
- Babarinde, T O, Akinlabi, S A, Madyira, D M, Ekundayo, F M, Adedeji, P A
- Authors: Babarinde, T O , Akinlabi, S A , Madyira, D M , Ekundayo, F M , Adedeji, P A
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/3248 , vital:43283 , https://www.sciencedirect.com/science/article/pii/S2352340920312105
- Description: This research paper assessed the performance of R600a with the base lubricant and Multi-walled Carbon Nanotube (MWCNT) nanolubricant at steady state. It describes the instruments required for measurement of the data parameter and its uncertainties, steps involved in preparing and replacing the MWCNT nanolubricant concentration with base lubricant in vapour compression refrigeration. The system’s temperature data was collected at the components inlets and outlets. Pressure data was also registered at the compressor outlet and inlet. The data was captured at 27 °C ambient temperature at an interval of 30 min for 300 min. The experiment includes the experimental data collection, Adaptive Neuro-Fuzzy Inference System (ANFIS) training and testing dataset. The use of ANFIS model is explained in predicting the efficiency of MWCNT nanolubricant in a vapour compression refrigerator system. The ANFIS model also provides statistical output measures such as Root Mean Square Error (RMSE) and Mean Absolute Deviation (MAD), Mean Absolute Percentage Error (MAPE), and determination coefficient (R2). The data is useful and important for replacing MWCNT nanolubricant with base lubricant in a vapour compression refrigeration system for researchers in the specialisation of energy-efficient materials in refrigeration. The data present can be reused for vapour compression refrigeration systems simulation and modelling.
- Full Text:
- Date Issued: 2020
- Authors: Babarinde, T O , Akinlabi, S A , Madyira, D M , Ekundayo, F M , Adedeji, P A
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/3248 , vital:43283 , https://www.sciencedirect.com/science/article/pii/S2352340920312105
- Description: This research paper assessed the performance of R600a with the base lubricant and Multi-walled Carbon Nanotube (MWCNT) nanolubricant at steady state. It describes the instruments required for measurement of the data parameter and its uncertainties, steps involved in preparing and replacing the MWCNT nanolubricant concentration with base lubricant in vapour compression refrigeration. The system’s temperature data was collected at the components inlets and outlets. Pressure data was also registered at the compressor outlet and inlet. The data was captured at 27 °C ambient temperature at an interval of 30 min for 300 min. The experiment includes the experimental data collection, Adaptive Neuro-Fuzzy Inference System (ANFIS) training and testing dataset. The use of ANFIS model is explained in predicting the efficiency of MWCNT nanolubricant in a vapour compression refrigerator system. The ANFIS model also provides statistical output measures such as Root Mean Square Error (RMSE) and Mean Absolute Deviation (MAD), Mean Absolute Percentage Error (MAPE), and determination coefficient (R2). The data is useful and important for replacing MWCNT nanolubricant with base lubricant in a vapour compression refrigeration system for researchers in the specialisation of energy-efficient materials in refrigeration. The data present can be reused for vapour compression refrigeration systems simulation and modelling.
- Full Text:
- Date Issued: 2020
Debunking the myth of lack of vocabulary for teaching content knowledge in primary schools: exploring terminology for science in Ekegusii of Kenya
- Authors: Mose, Peter
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150095 , vital:38939 , DOI: 10.1080/02572117.2020.1733827
- Description: The language-in-education policy to teach in mother tongues at lower primary level is not adhered to by classroom teachers in Kenya due to, among other reasons, lack of content terminology. The purpose of this study was to demonstrate that mother tongues can be used to teach science up to the end of grade three, considering the nature of topics for this level and other extra-classroom realities. Our research objectives were to examine the nature and content of science topics and sub-topics from grade one to grade three; examine conceptual and technical terms in grade one to grade three science textbooks; describe the Ekegusii equivalents of these terms; and explain the feasibility of teaching science in Ekegusii up to the end of grade three.
- Full Text:
- Date Issued: 2020
- Authors: Mose, Peter
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150095 , vital:38939 , DOI: 10.1080/02572117.2020.1733827
- Description: The language-in-education policy to teach in mother tongues at lower primary level is not adhered to by classroom teachers in Kenya due to, among other reasons, lack of content terminology. The purpose of this study was to demonstrate that mother tongues can be used to teach science up to the end of grade three, considering the nature of topics for this level and other extra-classroom realities. Our research objectives were to examine the nature and content of science topics and sub-topics from grade one to grade three; examine conceptual and technical terms in grade one to grade three science textbooks; describe the Ekegusii equivalents of these terms; and explain the feasibility of teaching science in Ekegusii up to the end of grade three.
- Full Text:
- Date Issued: 2020
Decent work and informal employment: the case of Bulawayo Metropolitan Province (Central Business District) Zimbabwe
- Authors: Bob, Shaka Keny
- Date: 2020
- Subjects: Labor -- Zimbabwe , Informal sector (Economics) -- Zimbabwe , Job creation -- Zimbabwe , Poor -- Zimbabwe -- Employment , Labor policy -- Zimbabwe , Football coaches -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/115241 , vital:34104
- Description: Zimbabwe, similar to other developing countries experiences a high level of informal employment. However, most informal jobs are situated in very poor working conditions and are characterised by decent work deficits. Despite the fact that various studies have shown the importance of the informal economy in that it provides livelihood earning opportunities for the majority of people in the Global South, it has remained a largely forgotten sector in policy making in most countries. It is, therefore, important that informal work be taken seriously and efforts must be made to improve working conditions for the urban working poor in the developing world. The purpose of this study is to investigate on the self-reported experiences of informal workers to understand their perspectives surrounding the concept of decent work in the Zimbabwean context. The case study is the Bulawayo metropolitan province, and this study targeted informal workers who trade within the central business district. The study also aimed to measure the decent work deficit scores between two economic sectors (food and clothing traders). This was done by testing the suitability of the Edward Webster Decent Work Deficit Index as a methodology of measuring decent work at a micro level. The analysis is based on a mixed methods study which was carried out through the use of a semi-structured survey. The study revealed that decent work for the sampled informal workers meant work related improvements, insurances and risk management, right of expression and business advancement skills which closely resembles the International Labour Organisation's conceptualisation of decent work. The study also highlighted that childcare assistance and disability insurance are concepts which remained excluded in the current conceptualisation of decent work. The thesis offers a new policy angle which shows that to promote decent work the concept of heterogeneity must be adopted because inequalities persist within the informal economy. The study also suggested that the Edward Webster Decent Work Deficit Index can be used as an appropriate methodology of monitoring the progress towards achieving decent work at the micro level i.e. industry or individual level. This is because since the formation of the decent work concept; the International Labour Organisation has only provided a methodology of how to measure the progress of decent work at the county level. The survey findings revealed that food vendors scored more poorly on the decent work deficit index compared to the clothing traders. The study also identified that food vendors and clothing traders are faced with different challenges which suggests that policy makers must take that into consideration when attempting to design policies or programmes which are aimed at assisting informal workers.
- Full Text:
- Date Issued: 2020
- Authors: Bob, Shaka Keny
- Date: 2020
- Subjects: Labor -- Zimbabwe , Informal sector (Economics) -- Zimbabwe , Job creation -- Zimbabwe , Poor -- Zimbabwe -- Employment , Labor policy -- Zimbabwe , Football coaches -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/115241 , vital:34104
- Description: Zimbabwe, similar to other developing countries experiences a high level of informal employment. However, most informal jobs are situated in very poor working conditions and are characterised by decent work deficits. Despite the fact that various studies have shown the importance of the informal economy in that it provides livelihood earning opportunities for the majority of people in the Global South, it has remained a largely forgotten sector in policy making in most countries. It is, therefore, important that informal work be taken seriously and efforts must be made to improve working conditions for the urban working poor in the developing world. The purpose of this study is to investigate on the self-reported experiences of informal workers to understand their perspectives surrounding the concept of decent work in the Zimbabwean context. The case study is the Bulawayo metropolitan province, and this study targeted informal workers who trade within the central business district. The study also aimed to measure the decent work deficit scores between two economic sectors (food and clothing traders). This was done by testing the suitability of the Edward Webster Decent Work Deficit Index as a methodology of measuring decent work at a micro level. The analysis is based on a mixed methods study which was carried out through the use of a semi-structured survey. The study revealed that decent work for the sampled informal workers meant work related improvements, insurances and risk management, right of expression and business advancement skills which closely resembles the International Labour Organisation's conceptualisation of decent work. The study also highlighted that childcare assistance and disability insurance are concepts which remained excluded in the current conceptualisation of decent work. The thesis offers a new policy angle which shows that to promote decent work the concept of heterogeneity must be adopted because inequalities persist within the informal economy. The study also suggested that the Edward Webster Decent Work Deficit Index can be used as an appropriate methodology of monitoring the progress towards achieving decent work at the micro level i.e. industry or individual level. This is because since the formation of the decent work concept; the International Labour Organisation has only provided a methodology of how to measure the progress of decent work at the county level. The survey findings revealed that food vendors scored more poorly on the decent work deficit index compared to the clothing traders. The study also identified that food vendors and clothing traders are faced with different challenges which suggests that policy makers must take that into consideration when attempting to design policies or programmes which are aimed at assisting informal workers.
- Full Text:
- Date Issued: 2020
Decision analysis to inform invasive alien plant management in the Garden Route Biosphere Reserve
- Authors: Masunungure, Current
- Date: 2020
- Subjects: Invasive plants -- South Africa , Alien plants -- South Africa , Biodiversity -- South Africa -- Management , Ecosystem management -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/49159 , vital:41606
- Description: Invasive alien plants (IAP) pose significant threats to global economies and biodiversity and are often considered as wicked problems. With an increasing number of IAP and limited resources, their management and decision-making processes are becoming difficult because of uncertainty, multiple and conflicting objectives, and diverse stakeholder views, facts and values. This is particularly challenging given the complex interactions between economic, ecological, and social elements that exist in invaded areas. Consequently, it is important to incorporate new ways of thinking and novel methodologies to improve our understanding of IAP management and the decision-making processes around them, which are currently inadequate. Decision analysis can help with dealing with these challenges and support decision-making under uncertainty. Drawing on the systems thinking approach and the concepts of leverage points, transition management and transformational change, the aim of this thesis was to explore the effectiveness of IAP management and the decision-making process in the Garden Route Biosphere Reserve (GRBR). This was achieved using a mixed methods approach involving: social-ecological inventory (identifying relevant stakeholders); review of literature on the available decision support tools; key informant interviews (stakeholder perspectives on the current decision-making process); and stakeholder workshop and expert consultation (casual loop modelling). The results of this thesis provide evidence that application of the proposed principles of robust decision-making has the potential to overcome the weaknesses of the current decision-making process and as such, enables decision-makers to efficiently allocate resources towards IAS management. A novel causal loop diagram (CLD) was developed to highlight the interconnections between key variables in IAP management and decision-making. This revealed that to transcend ‘policy resistance’ and ‘quickfixes that fail’ archetypes, and improve IAP management, the stakeholders need to consider deep leverage points, for example, fostering trust and shared understanding among different stakeholder groups. These can be realistically maintained over the long-term and can cause a fundamental change in IAP management, rather than focusing on shallow leverage points that are relatively easy to implement but do not result in significant systemic change. The findings of this thesis are flexible and could guide various stakeholder groups at local, national, and international scales in improving the effectiveness of IAP management and decision-making.
- Full Text:
- Date Issued: 2020
- Authors: Masunungure, Current
- Date: 2020
- Subjects: Invasive plants -- South Africa , Alien plants -- South Africa , Biodiversity -- South Africa -- Management , Ecosystem management -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/49159 , vital:41606
- Description: Invasive alien plants (IAP) pose significant threats to global economies and biodiversity and are often considered as wicked problems. With an increasing number of IAP and limited resources, their management and decision-making processes are becoming difficult because of uncertainty, multiple and conflicting objectives, and diverse stakeholder views, facts and values. This is particularly challenging given the complex interactions between economic, ecological, and social elements that exist in invaded areas. Consequently, it is important to incorporate new ways of thinking and novel methodologies to improve our understanding of IAP management and the decision-making processes around them, which are currently inadequate. Decision analysis can help with dealing with these challenges and support decision-making under uncertainty. Drawing on the systems thinking approach and the concepts of leverage points, transition management and transformational change, the aim of this thesis was to explore the effectiveness of IAP management and the decision-making process in the Garden Route Biosphere Reserve (GRBR). This was achieved using a mixed methods approach involving: social-ecological inventory (identifying relevant stakeholders); review of literature on the available decision support tools; key informant interviews (stakeholder perspectives on the current decision-making process); and stakeholder workshop and expert consultation (casual loop modelling). The results of this thesis provide evidence that application of the proposed principles of robust decision-making has the potential to overcome the weaknesses of the current decision-making process and as such, enables decision-makers to efficiently allocate resources towards IAS management. A novel causal loop diagram (CLD) was developed to highlight the interconnections between key variables in IAP management and decision-making. This revealed that to transcend ‘policy resistance’ and ‘quickfixes that fail’ archetypes, and improve IAP management, the stakeholders need to consider deep leverage points, for example, fostering trust and shared understanding among different stakeholder groups. These can be realistically maintained over the long-term and can cause a fundamental change in IAP management, rather than focusing on shallow leverage points that are relatively easy to implement but do not result in significant systemic change. The findings of this thesis are flexible and could guide various stakeholder groups at local, national, and international scales in improving the effectiveness of IAP management and decision-making.
- Full Text:
- Date Issued: 2020
Decolonisation as a spatial question: the student accommodation crisis and Higher Education transformation
- Mzileni, Pedro, Mkhize, Nomalanga
- Authors: Mzileni, Pedro , Mkhize, Nomalanga
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156378 , vital:39984 , DOI: 10.1080/21528586.2020.1733649
- Description: Debates on epistemological decolonisation have focused on curriculum issues. There has not been sufficient analysis of how questions of decolonisation are shaped by other factors, such as the very spatial location of universities. This article argues that the colonial nature of the university in South Africa is directly linked spatially to the historic land question of dispossession in South Africa. Historically, South African universities came to be fixed as physical and cultural elements of towns and cities based on the broader trajectory of settler-colonialism and apartheid urban development, segregation and the Group Areas logic of the apartheid state.
- Full Text:
- Date Issued: 2020
- Authors: Mzileni, Pedro , Mkhize, Nomalanga
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156378 , vital:39984 , DOI: 10.1080/21528586.2020.1733649
- Description: Debates on epistemological decolonisation have focused on curriculum issues. There has not been sufficient analysis of how questions of decolonisation are shaped by other factors, such as the very spatial location of universities. This article argues that the colonial nature of the university in South Africa is directly linked spatially to the historic land question of dispossession in South Africa. Historically, South African universities came to be fixed as physical and cultural elements of towns and cities based on the broader trajectory of settler-colonialism and apartheid urban development, segregation and the Group Areas logic of the apartheid state.
- Full Text:
- Date Issued: 2020
Decolonisation of nature in towns and cities of South Africa:
- Cocks, Michelle L, Shackleton, Charlie M, Walsh, Lindsey S, Haynes, Duncan, Manyani, Amanda, Radebe, Dennis
- Authors: Cocks, Michelle L , Shackleton, Charlie M , Walsh, Lindsey S , Haynes, Duncan , Manyani, Amanda , Radebe, Dennis
- Date: 2020
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/175720 , vital:42618 , ISBN 9781000215182
- Description: Ways of conceptualising the world around us and being in this world are defined by an ontological understanding. Within a Eurocentric ideological understanding, nature is positioned to be opposite to culture, ie, nature is considered as “other” of which humans are not a part. Modernity is perceived as the antithesis of nature as processes of production, metabolism and expansion of modern cities represent attempts to tame and control nature. In turn, cities have become viewed as agents of development and change, promoting ideals of progress, thinking and innovation (Jayne 2005). Eurocentric ideals are framed as the forerunners of these processes and have come to influence international policies, global governance, alliances and networks which have in turn informed the design and governance of cities and influenced all aspects of urban liveability (Bouteligier 2011), including how urban natures are defined and constructed and the wellbeing benefits derived from them.
- Full Text:
- Date Issued: 2020
- Authors: Cocks, Michelle L , Shackleton, Charlie M , Walsh, Lindsey S , Haynes, Duncan , Manyani, Amanda , Radebe, Dennis
- Date: 2020
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/175720 , vital:42618 , ISBN 9781000215182
- Description: Ways of conceptualising the world around us and being in this world are defined by an ontological understanding. Within a Eurocentric ideological understanding, nature is positioned to be opposite to culture, ie, nature is considered as “other” of which humans are not a part. Modernity is perceived as the antithesis of nature as processes of production, metabolism and expansion of modern cities represent attempts to tame and control nature. In turn, cities have become viewed as agents of development and change, promoting ideals of progress, thinking and innovation (Jayne 2005). Eurocentric ideals are framed as the forerunners of these processes and have come to influence international policies, global governance, alliances and networks which have in turn informed the design and governance of cities and influenced all aspects of urban liveability (Bouteligier 2011), including how urban natures are defined and constructed and the wellbeing benefits derived from them.
- Full Text:
- Date Issued: 2020
Decorated titania fibers as photocatalysts for hydrogen generation and organic matter degradation
- Mapukata, Sivuyisiwe, Hainer, Andrew S, Lanterna, Anabel E, Scaiano, Juan C, Nyokong, Tebello
- Authors: Mapukata, Sivuyisiwe , Hainer, Andrew S , Lanterna, Anabel E , Scaiano, Juan C , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186573 , vital:44513 , xlink:href="https://doi.org/10.1016/j.jphotochem.2019.112185"
- Description: Heterogenous photocatalysts based on electrospun fibers composed of polyvinylpyrrolidone and titanium propoxide were prepared and heated at 500, 750 and 950 °C to obtain anatase and rutile fibers. The fibers were then decorated with Pd and Co nanoparticles as well as a symmetrical zinc phthalocyanine (Pc). The fibrous materials obtained have a paper-like macroscopic appearance allowing for easy handling and separation. The photocatalytic activities of the new materials were evaluated for the generation of H2 upon UV (368 nm) or visible (630 nm) light excitation. Depending on the heat treatment or the post-synthetic decoration method, the materials show higher, or similar, activity compared to P25-TiO2, with superior ease of separation. The catalysts showed ability to degrade organic matter, with MeOH used as a model compound. This is of considerable importance for potential water treatment applications that will require flow-compatible materials.
- Full Text:
- Date Issued: 2020
- Authors: Mapukata, Sivuyisiwe , Hainer, Andrew S , Lanterna, Anabel E , Scaiano, Juan C , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186573 , vital:44513 , xlink:href="https://doi.org/10.1016/j.jphotochem.2019.112185"
- Description: Heterogenous photocatalysts based on electrospun fibers composed of polyvinylpyrrolidone and titanium propoxide were prepared and heated at 500, 750 and 950 °C to obtain anatase and rutile fibers. The fibers were then decorated with Pd and Co nanoparticles as well as a symmetrical zinc phthalocyanine (Pc). The fibrous materials obtained have a paper-like macroscopic appearance allowing for easy handling and separation. The photocatalytic activities of the new materials were evaluated for the generation of H2 upon UV (368 nm) or visible (630 nm) light excitation. Depending on the heat treatment or the post-synthetic decoration method, the materials show higher, or similar, activity compared to P25-TiO2, with superior ease of separation. The catalysts showed ability to degrade organic matter, with MeOH used as a model compound. This is of considerable importance for potential water treatment applications that will require flow-compatible materials.
- Full Text:
- Date Issued: 2020
Deep phylogeographic structure may indicate cryptic species within the Sparid genus Spondyliosoma:
- McKeown, Niall J, Gwilliam, Michael P, Healey, Amy J E, Skujina, Ilze, Potts, Warren M, Sauer, Warwick H H, Shaw, Paul W
- Authors: McKeown, Niall J , Gwilliam, Michael P , Healey, Amy J E , Skujina, Ilze , Potts, Warren M , Sauer, Warwick H H , Shaw, Paul W
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158085 , vital:40147 , DOI: 10.1111/jfb.14316
- Description: Two geographically nonoverlapping species are currently described within the sparid genus Spondyliosoma: Spondyliosoma cantharus (Black Seabream) occurring across Mediterranean and eastern Atlantic waters from NW Europe to Angola and S. emarginatum (Steentjie) considered endemic to southern Africa. To address prominent knowledge gaps this study investigated range‐wide phylogeographic structure across both species. Mitochondrial DNA sequences revealed deep phylogeographic structuring with four regionally partitioned reciprocally monophyletic clades, a Mediterranean clade and three more closely related Atlantic clades [NE Atlantic, Angola and South Africa (corresponding to S. emarginatum)]. Divergence and distribution of the lineages reflects survival in, and expansion from, disjunct glacial refuge areas. Cytonuclear differentiation of S. emarginatum supports its validity as a distinct species endemic to South African waters.
- Full Text:
- Date Issued: 2020
- Authors: McKeown, Niall J , Gwilliam, Michael P , Healey, Amy J E , Skujina, Ilze , Potts, Warren M , Sauer, Warwick H H , Shaw, Paul W
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158085 , vital:40147 , DOI: 10.1111/jfb.14316
- Description: Two geographically nonoverlapping species are currently described within the sparid genus Spondyliosoma: Spondyliosoma cantharus (Black Seabream) occurring across Mediterranean and eastern Atlantic waters from NW Europe to Angola and S. emarginatum (Steentjie) considered endemic to southern Africa. To address prominent knowledge gaps this study investigated range‐wide phylogeographic structure across both species. Mitochondrial DNA sequences revealed deep phylogeographic structuring with four regionally partitioned reciprocally monophyletic clades, a Mediterranean clade and three more closely related Atlantic clades [NE Atlantic, Angola and South Africa (corresponding to S. emarginatum)]. Divergence and distribution of the lineages reflects survival in, and expansion from, disjunct glacial refuge areas. Cytonuclear differentiation of S. emarginatum supports its validity as a distinct species endemic to South African waters.
- Full Text:
- Date Issued: 2020
Default in payment, an application of statistical learning techniques
- Authors: Gcakasi, Lulama
- Date: 2020
- Subjects: Credit -- South Africa -- Risk assessment , Risk management -- Statistical methods -- South Africa , Credit -- Management -- Statistical methods , Commercial statistics
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/141547 , vital:37984
- Description: The ability of financial institutions to detect whether a customer will default on their credit card payment is essential for its profitability. To that effect, financial institutions have credit scoring systems in place to be able to estimate the credit risk associated with a customer. Various classification models are used to develop credit scoring systems such as k-nearest neighbours, logistic regression and classification trees. This study aims to assess the performance of different classification models on the prediction of credit card payment default. Credit data is usually of high dimension and as a result dimension reduction techniques, namely principal component analysis and linear discriminant analysis, are used in this study as a means to improve model performance. Two classification models are used, namely neural networks and support vector machines. Model performance is evaluated using accuracy and area under the curve (AUC). The neuarl network classifier performed better than the support vector machine classifier as it produced higher accuracy rates and AUC values. Dimension reduction techniques were not effective in improving model performance but did result in less computationally expensive models.
- Full Text:
- Date Issued: 2020
- Authors: Gcakasi, Lulama
- Date: 2020
- Subjects: Credit -- South Africa -- Risk assessment , Risk management -- Statistical methods -- South Africa , Credit -- Management -- Statistical methods , Commercial statistics
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/141547 , vital:37984
- Description: The ability of financial institutions to detect whether a customer will default on their credit card payment is essential for its profitability. To that effect, financial institutions have credit scoring systems in place to be able to estimate the credit risk associated with a customer. Various classification models are used to develop credit scoring systems such as k-nearest neighbours, logistic regression and classification trees. This study aims to assess the performance of different classification models on the prediction of credit card payment default. Credit data is usually of high dimension and as a result dimension reduction techniques, namely principal component analysis and linear discriminant analysis, are used in this study as a means to improve model performance. Two classification models are used, namely neural networks and support vector machines. Model performance is evaluated using accuracy and area under the curve (AUC). The neuarl network classifier performed better than the support vector machine classifier as it produced higher accuracy rates and AUC values. Dimension reduction techniques were not effective in improving model performance but did result in less computationally expensive models.
- Full Text:
- Date Issued: 2020
Defect Classification in Photovoltaic Modules through Thermal Infrared Imaging using Machine Learning
- Dunderdale, Christopher, Clohessy, C M
- Authors: Dunderdale, Christopher , Clohessy, C M
- Date: 2020
- Subjects: Photovoltaic power generation -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/48280 , vital:40838
- Description: As the global energy demand continues to soar, solar energy has become an attractive and environmentally conscious method to meet this demand. This study examines the use of machine learning techniques for defect detection and classification in photovoltaic systems using thermal infrared images. A deep learning and feature-based approach is also investigated for the purpose of detecting and classifying defective photovoltaic modules. The VGG-16 and MobileNet deep learning models are shown to provide good performance for the classification of defects. The scale invariant feature transform (SIFT) descriptor, combined with the random forest and support vector machine classifier, is also used to discriminate between defective and non-defective photovoltaic modules in a South African setting. The successful implementation of this approach has significant potential for cost reduction in defect classification over currently available methods.
- Full Text:
- Date Issued: 2020
- Authors: Dunderdale, Christopher , Clohessy, C M
- Date: 2020
- Subjects: Photovoltaic power generation -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/48280 , vital:40838
- Description: As the global energy demand continues to soar, solar energy has become an attractive and environmentally conscious method to meet this demand. This study examines the use of machine learning techniques for defect detection and classification in photovoltaic systems using thermal infrared images. A deep learning and feature-based approach is also investigated for the purpose of detecting and classifying defective photovoltaic modules. The VGG-16 and MobileNet deep learning models are shown to provide good performance for the classification of defects. The scale invariant feature transform (SIFT) descriptor, combined with the random forest and support vector machine classifier, is also used to discriminate between defective and non-defective photovoltaic modules in a South African setting. The successful implementation of this approach has significant potential for cost reduction in defect classification over currently available methods.
- Full Text:
- Date Issued: 2020
Defining the potential ecological roles of three sea turtle species (Caretta caretta, Chelonia mydas and Eretmochelys imbricata) along the Eastern seaboard of South Africa
- Authors: Ramboran, Ryan
- Date: 2020
- Subjects: Sea turtles -- Conservation -- South Africa , Sea turtles -- Habitat -- Conservation -- South Africa Marine ecology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/49343 , vital:41623
- Description: Sea turtles were once key species, driving the ecosystem process and energy flows, the past loss of their ecological roles, however has resulted in reduced ecosystem functionality through food web shifts and trophic cascades. Therefore understanding the past and present ecological roles of sea turtles is identified as one of the global research priorities for sea turtle management and conservation.
- Full Text: false
- Date Issued: 2020
- Authors: Ramboran, Ryan
- Date: 2020
- Subjects: Sea turtles -- Conservation -- South Africa , Sea turtles -- Habitat -- Conservation -- South Africa Marine ecology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/49343 , vital:41623
- Description: Sea turtles were once key species, driving the ecosystem process and energy flows, the past loss of their ecological roles, however has resulted in reduced ecosystem functionality through food web shifts and trophic cascades. Therefore understanding the past and present ecological roles of sea turtles is identified as one of the global research priorities for sea turtle management and conservation.
- Full Text: false
- Date Issued: 2020
Delineating functional properties of a cello-oligosaccharide and Bglucan specific cellobiohydrolase (GH5_38): Its synergism with Cel6A and Cel7A for B-(1,3)-(1,4)-glucan degradation
- Mafa, Mpho S, Malgas, Samkelo, Rashamuse, Konanani, Pletschke, Brett I
- Authors: Mafa, Mpho S , Malgas, Samkelo , Rashamuse, Konanani , Pletschke, Brett I
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429425 , vital:72609 , xlink:href="https://doi.org/10.1016/j.carres.2020.108081"
- Description: Cellulase cocktails formulated to degrade crystalline cellulose generally contain cellobiohydrolases (CBHs), referred to as CBHI (Cel7A) and CBHII (Cel6A), as the major constituents. The combined hydrolytic activities of CBHI and CBHII improve the release of fermentable sugars (β-1,4-cellobiose as the main product) from crystalline cellulose. In this study, a novel cellobiohydrolase (Exg-D) sourced from a metagenome of hindgut bacterial symbionts of a termite was heterologouly expressed, purified, and functionally characterised. Exg-D specific activity was higher on insoluble barley β-glucan (38.94 U/mg protein), soluble wheat flour β-glucan (12.71 U/mg protein) and oat β-glucan (8.89 U/mg protein) compared to cellulosic substrates; Avicel and CMC. We further explored Exg-D activity on the unpretreated or NaOH-pretreated (mercerised) Avicel and compared its activity to commercially available CBHI and CBHII on these celluloses. CBHI displayed the highest activity of 4.74 U/mg protein on mercerised cellulose followed by CBHII (2.14 U/mg protein), while Exg-D activity on untreated and mercerised cellulose was 1.66 and 1.67 U/mg protein, respectively. The high activity of CBHI was supported by binding assays, which revealed that CBHI has a higher binding capacity towards crystalline cellulose compared to Exg-D and CBHII. Only CBHI and CBHII showed synergism during the hydrolysis of mercerised Avicel, showing a degree of synergy (DS) of about 1.299 and yielded about 1.43 μmol/ml of reducing sugars higher than control. In contrast, Exg-D and CBHII displayed synergism during β-glucan degradation, displaying a DS of about 1.22. Thus, we propose that Exg-D should only be used synergistically with other CBHs to degrade mixed linked-β-(1,3)-(1,4)-glucan.
- Full Text:
- Date Issued: 2020
- Authors: Mafa, Mpho S , Malgas, Samkelo , Rashamuse, Konanani , Pletschke, Brett I
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429425 , vital:72609 , xlink:href="https://doi.org/10.1016/j.carres.2020.108081"
- Description: Cellulase cocktails formulated to degrade crystalline cellulose generally contain cellobiohydrolases (CBHs), referred to as CBHI (Cel7A) and CBHII (Cel6A), as the major constituents. The combined hydrolytic activities of CBHI and CBHII improve the release of fermentable sugars (β-1,4-cellobiose as the main product) from crystalline cellulose. In this study, a novel cellobiohydrolase (Exg-D) sourced from a metagenome of hindgut bacterial symbionts of a termite was heterologouly expressed, purified, and functionally characterised. Exg-D specific activity was higher on insoluble barley β-glucan (38.94 U/mg protein), soluble wheat flour β-glucan (12.71 U/mg protein) and oat β-glucan (8.89 U/mg protein) compared to cellulosic substrates; Avicel and CMC. We further explored Exg-D activity on the unpretreated or NaOH-pretreated (mercerised) Avicel and compared its activity to commercially available CBHI and CBHII on these celluloses. CBHI displayed the highest activity of 4.74 U/mg protein on mercerised cellulose followed by CBHII (2.14 U/mg protein), while Exg-D activity on untreated and mercerised cellulose was 1.66 and 1.67 U/mg protein, respectively. The high activity of CBHI was supported by binding assays, which revealed that CBHI has a higher binding capacity towards crystalline cellulose compared to Exg-D and CBHII. Only CBHI and CBHII showed synergism during the hydrolysis of mercerised Avicel, showing a degree of synergy (DS) of about 1.299 and yielded about 1.43 μmol/ml of reducing sugars higher than control. In contrast, Exg-D and CBHII displayed synergism during β-glucan degradation, displaying a DS of about 1.22. Thus, we propose that Exg-D should only be used synergistically with other CBHs to degrade mixed linked-β-(1,3)-(1,4)-glucan.
- Full Text:
- Date Issued: 2020
Derivative actions in contemporary company law: A comparative assessment from an enhanced accountability perspective
- Authors: Hamadziripi , Friedrich
- Date: 2020
- Subjects: Judicial discretion
- Language: English
- Type: Thesis , Doctoral , LLD
- Identifier: http://hdl.handle.net/10353/18336 , vital:42253
- Description: The company is one of the most popular organisational vehicles for conducting business. The very nature of the company as a juristic person is attractive. The principle of legal personality entitles a company to act as a legal entity separate from its members. The principle was laid down in the landmark decision of Salomon v Salomon 1897 AC 22 (HL). This decision shows that a company is a full player in the legal arena. It has standing before the courts of law and is the proper plaintiff for wrongs done to it, not any of the stakeholders who may also be affected by the wrongdoing. However, it has to be noted that a company is just an artificial person. It is a fictitious being, a juristic person and a creature of statute. Therefore, even though a company has the capacity to acquire rights which can be enforced in a court of law and obligations which another legal subject can enforce against it, a company cannot in all respects be equated with a human person, for it has no physical substance. Inevitably, a director must act as its hands, brain, legs, mouth and eyes. Regardless of how financially strong a company can be, its juristic nature places all its resources and wealth at the mercy of its directors and officers. A company can neither protect itself against wrongdoing, vindicate nor enforce its rights without its representative directors and officers. If the wrongdoing faction in a company comprises of directors who are required to act in the best interests of the company, then who will enforce the company’s rights? The juristic nature of a company makes it vulnerable to abuse, especially by directors. It is important to note that internal stakeholders such as directors innocent of wrongdoing, employees and shareholders are not the only ones who stand to lose from the failure of corporate governance. External stakeholders’ interests too are vulnerable to abuse as a result of a company being abused by its leaders. There is, therefore, a need for a mechanism that controls abuse of power especially by agents of a company. Such a mechanism is critical to accountability as it protects the company from director malfeasance while promoting adherence to corporate governance principles in general. Also, successful derivative claims play a significant role in securing compensation for the company. Seeing that a company can be injured by both internal and external stakeholders, it is imperative that there be an effective and efficient mechanism that protects both the company and its owners without deterring entrepreneurship and stakeholder participation. Proceeding from an iii accountability enhancement perspective, this study undertakes a comparative assessment of the derivative action as a mechanism that created to deal effectively with the mischief revealed in the above paragraphs. For a complainant to be able to invoke the derivative action for relief, he or she must comply with certain requirements. Those requirements will be examined in greater detail with respect to the American, South African, English and Japanese laws. Empirical research has concluded that directors’ exposure to derivative claims remains largely theoretical. The critical question is whether the requirements for commencing or continuing a derivative action are too onerous. Although the remedy is available in theory, its shortcomings appear to make derivative actions almost impossible to invoke in practice. It has been argued that the greatest impediment to a derivative action by minority shareholders arises from the practical barriers to the commencement of derivative proceedings. With respect to the USA, it has further been demonstrated that there is a positive correlation between the significant decline in the importance of derivative litigation and the creation of additional legal hurdles in breach of directors’ duties cases. This study seeks to examine the various shortcomings of the remedy and suggest ways to make it less onerous as well as increase its availability to more stakeholders
- Full Text:
- Date Issued: 2020
- Authors: Hamadziripi , Friedrich
- Date: 2020
- Subjects: Judicial discretion
- Language: English
- Type: Thesis , Doctoral , LLD
- Identifier: http://hdl.handle.net/10353/18336 , vital:42253
- Description: The company is one of the most popular organisational vehicles for conducting business. The very nature of the company as a juristic person is attractive. The principle of legal personality entitles a company to act as a legal entity separate from its members. The principle was laid down in the landmark decision of Salomon v Salomon 1897 AC 22 (HL). This decision shows that a company is a full player in the legal arena. It has standing before the courts of law and is the proper plaintiff for wrongs done to it, not any of the stakeholders who may also be affected by the wrongdoing. However, it has to be noted that a company is just an artificial person. It is a fictitious being, a juristic person and a creature of statute. Therefore, even though a company has the capacity to acquire rights which can be enforced in a court of law and obligations which another legal subject can enforce against it, a company cannot in all respects be equated with a human person, for it has no physical substance. Inevitably, a director must act as its hands, brain, legs, mouth and eyes. Regardless of how financially strong a company can be, its juristic nature places all its resources and wealth at the mercy of its directors and officers. A company can neither protect itself against wrongdoing, vindicate nor enforce its rights without its representative directors and officers. If the wrongdoing faction in a company comprises of directors who are required to act in the best interests of the company, then who will enforce the company’s rights? The juristic nature of a company makes it vulnerable to abuse, especially by directors. It is important to note that internal stakeholders such as directors innocent of wrongdoing, employees and shareholders are not the only ones who stand to lose from the failure of corporate governance. External stakeholders’ interests too are vulnerable to abuse as a result of a company being abused by its leaders. There is, therefore, a need for a mechanism that controls abuse of power especially by agents of a company. Such a mechanism is critical to accountability as it protects the company from director malfeasance while promoting adherence to corporate governance principles in general. Also, successful derivative claims play a significant role in securing compensation for the company. Seeing that a company can be injured by both internal and external stakeholders, it is imperative that there be an effective and efficient mechanism that protects both the company and its owners without deterring entrepreneurship and stakeholder participation. Proceeding from an iii accountability enhancement perspective, this study undertakes a comparative assessment of the derivative action as a mechanism that created to deal effectively with the mischief revealed in the above paragraphs. For a complainant to be able to invoke the derivative action for relief, he or she must comply with certain requirements. Those requirements will be examined in greater detail with respect to the American, South African, English and Japanese laws. Empirical research has concluded that directors’ exposure to derivative claims remains largely theoretical. The critical question is whether the requirements for commencing or continuing a derivative action are too onerous. Although the remedy is available in theory, its shortcomings appear to make derivative actions almost impossible to invoke in practice. It has been argued that the greatest impediment to a derivative action by minority shareholders arises from the practical barriers to the commencement of derivative proceedings. With respect to the USA, it has further been demonstrated that there is a positive correlation between the significant decline in the importance of derivative litigation and the creation of additional legal hurdles in breach of directors’ duties cases. This study seeks to examine the various shortcomings of the remedy and suggest ways to make it less onerous as well as increase its availability to more stakeholders
- Full Text:
- Date Issued: 2020