A framework for the management of environmental information in Higher Education Institutions
- Authors: Jonamu, Blessing Tapiwa
- Date: 2014
- Subjects: Sustainability , Universities and colleges , Environmental management
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10492 , http://hdl.handle.net/10948/d1020620
- Description: Higher Education Institutions (HEIs) are not immune to the global environment problems. An increasing awareness of the environmental responsibilities of HEIs has led researchers to investigate the role of environmental information and Environmental Management Information Systems (EMISs) in HEIs. EMISs play a major role in environmental management and environmental decision making in HEIs. Internationally, an increasing number of HEIs are embracing the concept of ‘sustainable HEIs’ by undertaking green campus initiatives. HEIs often use diverse information systems, some of which are manual systems, proven to be inefficient and this gives rise to redundant and inconsistent databases which result in non-compliance with regulations, confusion and lack of co-ordinated effort. There is therefore need for an integrated, comprehensive software system and framework which can assist with the efficient management of environmental information at South African HEIs. This study fills a gap in the field of environmental sustainability at HEIs as the evaluation of existing sustainability programs has shown common weakness such as: Failure to effectively set baselines, flaws in data acquisition and management and missing documentation. The aim of this study is to propose a framework for Environmental Information Management (EIM) in HEIs. The framework includes guidelines related to the components of the framework which can also be used to perform a gap analysis to facilitate the improved design of effective and efficient EIM processes and data stores. The Design Science Research (DSR) methodology is the research methodology used in the development of the two artifacts of this study namely: The EIM framework for HEIs and an EMIS prototype to serve as proof of concept. Problem identification and motivation was the first activity of the DSR which was done through a rigorous literature review and an investigation and evaluation of extant systems. This resulted in the design of an initial EIM framework for HEIs. Nelson Mandela Metropolitan University (NMMU) was the HEI used as the case study. The EIM framework was applied at NMMU and this enabled the researcher to understand the current As-Is EIM processes at NMMU and this resulted in clear objectives of a solution. The EMIS prototype (data warehouse) was then designed and implemented based on the theoretical framework. Three sets of evaluations were done to determine the acceptance of the EIM framework for HEIs and the performance of the EMIS prototype. The EIM framework was generally positively accepted and minor suggestions were made. An updated version of the EIM framework was proposed and evaluated. The experimental evaluation results showed that the EMIS prototype was efficient and effective. The contribution of this study is an EIM framework for HEIs and an implementation of an EMIS (EnviroDW) at NMMU that could be utilised by other HEIs.
- Full Text:
- Date Issued: 2014
- Authors: Jonamu, Blessing Tapiwa
- Date: 2014
- Subjects: Sustainability , Universities and colleges , Environmental management
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10492 , http://hdl.handle.net/10948/d1020620
- Description: Higher Education Institutions (HEIs) are not immune to the global environment problems. An increasing awareness of the environmental responsibilities of HEIs has led researchers to investigate the role of environmental information and Environmental Management Information Systems (EMISs) in HEIs. EMISs play a major role in environmental management and environmental decision making in HEIs. Internationally, an increasing number of HEIs are embracing the concept of ‘sustainable HEIs’ by undertaking green campus initiatives. HEIs often use diverse information systems, some of which are manual systems, proven to be inefficient and this gives rise to redundant and inconsistent databases which result in non-compliance with regulations, confusion and lack of co-ordinated effort. There is therefore need for an integrated, comprehensive software system and framework which can assist with the efficient management of environmental information at South African HEIs. This study fills a gap in the field of environmental sustainability at HEIs as the evaluation of existing sustainability programs has shown common weakness such as: Failure to effectively set baselines, flaws in data acquisition and management and missing documentation. The aim of this study is to propose a framework for Environmental Information Management (EIM) in HEIs. The framework includes guidelines related to the components of the framework which can also be used to perform a gap analysis to facilitate the improved design of effective and efficient EIM processes and data stores. The Design Science Research (DSR) methodology is the research methodology used in the development of the two artifacts of this study namely: The EIM framework for HEIs and an EMIS prototype to serve as proof of concept. Problem identification and motivation was the first activity of the DSR which was done through a rigorous literature review and an investigation and evaluation of extant systems. This resulted in the design of an initial EIM framework for HEIs. Nelson Mandela Metropolitan University (NMMU) was the HEI used as the case study. The EIM framework was applied at NMMU and this enabled the researcher to understand the current As-Is EIM processes at NMMU and this resulted in clear objectives of a solution. The EMIS prototype (data warehouse) was then designed and implemented based on the theoretical framework. Three sets of evaluations were done to determine the acceptance of the EIM framework for HEIs and the performance of the EMIS prototype. The EIM framework was generally positively accepted and minor suggestions were made. An updated version of the EIM framework was proposed and evaluated. The experimental evaluation results showed that the EMIS prototype was efficient and effective. The contribution of this study is an EIM framework for HEIs and an implementation of an EMIS (EnviroDW) at NMMU that could be utilised by other HEIs.
- Full Text:
- Date Issued: 2014
A hybrid model for managing personal health records in South Africa
- Authors: Kyazze, Michael
- Date: 2014
- Subjects: Cloud computing -- South Africa , Information storage and retrieval systems -- Medical care -- South Africa , Medical records -- Management -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/3145 , vital:20403
- Description: Doctors can experience difficulty in accessing medical information of new patients. One reason for this is that the management of medical records is mostly institution-centred. The lack of access to medical information may negatively affect patients in several ways. These include new medical tests that may need to be carried out at a cost to the patient and doctors prescribing drugs to which the patient is allergic. This research investigates how patients can play an active role in sharing their personal health records (PHRs) with doctors located in geographically separate areas. In order to achieve the goal of this research, existing literature concerning medical health records and standards was reviewed. A literature review of techniques that can be used to ensure privacy of health information was also undertaken. Interview studies were carried out with three medical practices in Port Elizabeth with the aim of contextualising the findings from the literature study. The Design Science Research methodology was used for this research. A Hybrid Model for Managing Personal Health Records in South Africa is proposed. This model allows patients to view their PHRs on their mobile phones and medical practitioners to manage the patients’ PHRs using a web-based application. The patients’ PHR information is stored both on a cloud server and on mobile devices hence the hybrid nature. Two prototypes were developed as a proof of concept; a mobile application for the patients and a web-based application for the medical practitioners. A field study was carried out with the NMMU health services department and 12 participants over a period of two weeks. The results of the field study were highly positive. The successful evaluation of the prototypes provides empirical evidence that the proposed model brings us closer to the realisation of ubiquitous access to PHRS in South Africa.
- Full Text:
- Date Issued: 2014
- Authors: Kyazze, Michael
- Date: 2014
- Subjects: Cloud computing -- South Africa , Information storage and retrieval systems -- Medical care -- South Africa , Medical records -- Management -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/3145 , vital:20403
- Description: Doctors can experience difficulty in accessing medical information of new patients. One reason for this is that the management of medical records is mostly institution-centred. The lack of access to medical information may negatively affect patients in several ways. These include new medical tests that may need to be carried out at a cost to the patient and doctors prescribing drugs to which the patient is allergic. This research investigates how patients can play an active role in sharing their personal health records (PHRs) with doctors located in geographically separate areas. In order to achieve the goal of this research, existing literature concerning medical health records and standards was reviewed. A literature review of techniques that can be used to ensure privacy of health information was also undertaken. Interview studies were carried out with three medical practices in Port Elizabeth with the aim of contextualising the findings from the literature study. The Design Science Research methodology was used for this research. A Hybrid Model for Managing Personal Health Records in South Africa is proposed. This model allows patients to view their PHRs on their mobile phones and medical practitioners to manage the patients’ PHRs using a web-based application. The patients’ PHR information is stored both on a cloud server and on mobile devices hence the hybrid nature. Two prototypes were developed as a proof of concept; a mobile application for the patients and a web-based application for the medical practitioners. A field study was carried out with the NMMU health services department and 12 participants over a period of two weeks. The results of the field study were highly positive. The successful evaluation of the prototypes provides empirical evidence that the proposed model brings us closer to the realisation of ubiquitous access to PHRS in South Africa.
- Full Text:
- Date Issued: 2014
A hybridisation technique for game playing using the upper confidence for trees algorithm with artificial neural networks
- Authors: Burger, Clayton
- Date: 2014
- Subjects: Neural networks (Computer science) , Computer algorithms
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/3957 , vital:20495
- Description: In the domain of strategic game playing, the use of statistical techniques such as the Upper Confidence for Trees (UCT) algorithm, has become the norm as they offer many benefits over classical algorithms. These benefits include requiring no game-specific strategic knowledge and time-scalable performance. UCT does not incorporate any strategic information specific to the game considered, but instead uses repeated sampling to effectively brute-force search through the game tree or search space. The lack of game-specific knowledge in UCT is thus both a benefit but also a strategic disadvantage. Pattern recognition techniques, specifically Neural Networks (NN), were identified as a means of addressing the lack of game-specific knowledge in UCT. Through a novel hybridisation technique which combines UCT and trained NNs for pruning, the UCTNN algorithm was derived. The NN component of UCT-NN was trained using a UCT self-play scheme to generate game-specific knowledge without the need to construct and manage game databases for training purposes. The UCT-NN algorithm is outlined for pruning in the game of Go-Moku as a candidate case-study for this research. The UCT-NN algorithm contained three major parameters which emerged from the UCT algorithm, the use of NNs and the pruning schemes considered. Suitable methods for finding candidate values for these three parameters were outlined and applied to the game of Go-Moku on a 5 by 5 board. An empirical investigation of the playing performance of UCT-NN was conducted in comparison to UCT through three benchmarks. The benchmarks comprise a common randomly moving opponent, a common UCTmax player which is given a large amount of playing time, and a pair-wise tournament between UCT-NN and UCT. The results of the performance evaluation for 5 by 5 Go-Moku were promising, which prompted an evaluation of a larger 9 by 9 Go-Moku board. The results of both evaluations indicate that the time allocated to the UCT-NN algorithm directly affects its performance when compared to UCT. The UCT-NN algorithm generally performs better than UCT in games with very limited time-constraints in all benchmarks considered except when playing against a randomly moving player in 9 by 9 Go-Moku. In real-time and near-real-time Go-Moku games, UCT-NN provides statistically significant improvements compared to UCT. The findings of this research contribute to the realisation of applying game-specific knowledge to the UCT algorithm.
- Full Text:
- Date Issued: 2014
- Authors: Burger, Clayton
- Date: 2014
- Subjects: Neural networks (Computer science) , Computer algorithms
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/3957 , vital:20495
- Description: In the domain of strategic game playing, the use of statistical techniques such as the Upper Confidence for Trees (UCT) algorithm, has become the norm as they offer many benefits over classical algorithms. These benefits include requiring no game-specific strategic knowledge and time-scalable performance. UCT does not incorporate any strategic information specific to the game considered, but instead uses repeated sampling to effectively brute-force search through the game tree or search space. The lack of game-specific knowledge in UCT is thus both a benefit but also a strategic disadvantage. Pattern recognition techniques, specifically Neural Networks (NN), were identified as a means of addressing the lack of game-specific knowledge in UCT. Through a novel hybridisation technique which combines UCT and trained NNs for pruning, the UCTNN algorithm was derived. The NN component of UCT-NN was trained using a UCT self-play scheme to generate game-specific knowledge without the need to construct and manage game databases for training purposes. The UCT-NN algorithm is outlined for pruning in the game of Go-Moku as a candidate case-study for this research. The UCT-NN algorithm contained three major parameters which emerged from the UCT algorithm, the use of NNs and the pruning schemes considered. Suitable methods for finding candidate values for these three parameters were outlined and applied to the game of Go-Moku on a 5 by 5 board. An empirical investigation of the playing performance of UCT-NN was conducted in comparison to UCT through three benchmarks. The benchmarks comprise a common randomly moving opponent, a common UCTmax player which is given a large amount of playing time, and a pair-wise tournament between UCT-NN and UCT. The results of the performance evaluation for 5 by 5 Go-Moku were promising, which prompted an evaluation of a larger 9 by 9 Go-Moku board. The results of both evaluations indicate that the time allocated to the UCT-NN algorithm directly affects its performance when compared to UCT. The UCT-NN algorithm generally performs better than UCT in games with very limited time-constraints in all benchmarks considered except when playing against a randomly moving player in 9 by 9 Go-Moku. In real-time and near-real-time Go-Moku games, UCT-NN provides statistically significant improvements compared to UCT. The findings of this research contribute to the realisation of applying game-specific knowledge to the UCT algorithm.
- Full Text:
- Date Issued: 2014
An architecutre for the effective use of mobile devices in supporting contact learning
- Authors: Alnseerat, Nemr
- Date: 2014
- Subjects: Mobile communication systems in education , Educational technology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10490 , http://hdl.handle.net/10948/d1020079
- Description: The features and capacities of mobile devices offer a wide range of significant opportunities for providing learning content in workplaces and educational institutions. This new approach of teaching, called mobile learning, allows for the delivery of learning content on the move at any time. Mobile learning supports learning by producing learning content to learners in a modern and acceptable way. The number of mobile learning applications has increased rapidly in educational environments. There are, however, limited mobile learning applications that take advantage of mobile devices to support contact learning in the classroom environment. The aim of this research was to design a mobile learning architecture to effectively support contact learning in the classroom. The researcher investigated the historical and theoretical background of mobile learning and reported these findings. This included an overview of existing mobile learning architectures. After identifying their limitations, the researcher designed the Contact Instruction Mobile Learning Architecture (CIMLA) to facilitate the use of mobile devices in the classroom. The researcher developed the LiveLearning prototype based on the proposed architecture as a proof of concept. He conducted a usability evaluation in order to determine the usability of LiveLearning. The results indicated that the LiveLearning prototype is effective in supporting contact learning in the classroom.
- Full Text:
- Date Issued: 2014
- Authors: Alnseerat, Nemr
- Date: 2014
- Subjects: Mobile communication systems in education , Educational technology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10490 , http://hdl.handle.net/10948/d1020079
- Description: The features and capacities of mobile devices offer a wide range of significant opportunities for providing learning content in workplaces and educational institutions. This new approach of teaching, called mobile learning, allows for the delivery of learning content on the move at any time. Mobile learning supports learning by producing learning content to learners in a modern and acceptable way. The number of mobile learning applications has increased rapidly in educational environments. There are, however, limited mobile learning applications that take advantage of mobile devices to support contact learning in the classroom environment. The aim of this research was to design a mobile learning architecture to effectively support contact learning in the classroom. The researcher investigated the historical and theoretical background of mobile learning and reported these findings. This included an overview of existing mobile learning architectures. After identifying their limitations, the researcher designed the Contact Instruction Mobile Learning Architecture (CIMLA) to facilitate the use of mobile devices in the classroom. The researcher developed the LiveLearning prototype based on the proposed architecture as a proof of concept. He conducted a usability evaluation in order to determine the usability of LiveLearning. The results indicated that the LiveLearning prototype is effective in supporting contact learning in the classroom.
- Full Text:
- Date Issued: 2014
An investigation into the use of a ceramifiable Ethylene Vinyl Acetate (EVA) co-polymer formulation to aid flame retardency in electrical cables
- Authors: Bambalaza, Sonwabo Elvis
- Date: 2014
- Subjects: Vinyl acetate , Polymeric composites , Inorganic compounds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10433 , http://hdl.handle.net/10948/d1020159
- Description: The concept of a unique ceramifiable Ethylene vinyl acetate (EVA) based polymer composite was based on the incorporation of inorganic compounds such as aluminium hydroxide, calcium carbonate, muscovite mica, and calcined kaolinite within a 95 percent EVA/ 5 percent Polydimethylsiloxane (PDMS) polymer matrix such tha t upon heating to elevated temperatures of about 1000 oC, a solid end-product with ceramic-like properties would be formed. The ceramifiable EVA based polymer composite was developed to be used as electric cable insulation or sheath as the formation of a ceramic based material at elevated temperatures would provide flame retardant properties during fire situations. The flame retardant properties at elevated temperatures would ensure that the insulation remains at such temperatures due to some of the properties of the resultant ceramic such as reasonably high flexural strength, high thermal stability, non-reactivity and high melting point. During a fire this would ensure that flames would not be propagated along the length of the cable and also protect the underlying conducting wires from being exposed to the high temperatures of the fire. Its application as a cable insulation also required that the material functions as a cable insulator under ambient temperature conditions where the ceramifiable polymer composite should retain certain polymer properties such as the post-cure tensile strength (MPa), degree of polymer elongation (percent), thermal expansion, thermal slacking, limited oxygen index and electrical insulation. This study made use of a composite experimental design approach that would allow for the optimization of the amounts of the additives in the ceramifiable polymer composite giving both the desired mechanical properties of the material under normal operating temperatures as a polymer and also as a ceramic once exposed to elevated temperatures. The optimization of additives used in the ceramifiable polymer composite was done by using a D-optimal mixture design of experiments (DoE) which was analyzed by multiple linear regression.
- Full Text:
- Date Issued: 2014
- Authors: Bambalaza, Sonwabo Elvis
- Date: 2014
- Subjects: Vinyl acetate , Polymeric composites , Inorganic compounds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10433 , http://hdl.handle.net/10948/d1020159
- Description: The concept of a unique ceramifiable Ethylene vinyl acetate (EVA) based polymer composite was based on the incorporation of inorganic compounds such as aluminium hydroxide, calcium carbonate, muscovite mica, and calcined kaolinite within a 95 percent EVA/ 5 percent Polydimethylsiloxane (PDMS) polymer matrix such tha t upon heating to elevated temperatures of about 1000 oC, a solid end-product with ceramic-like properties would be formed. The ceramifiable EVA based polymer composite was developed to be used as electric cable insulation or sheath as the formation of a ceramic based material at elevated temperatures would provide flame retardant properties during fire situations. The flame retardant properties at elevated temperatures would ensure that the insulation remains at such temperatures due to some of the properties of the resultant ceramic such as reasonably high flexural strength, high thermal stability, non-reactivity and high melting point. During a fire this would ensure that flames would not be propagated along the length of the cable and also protect the underlying conducting wires from being exposed to the high temperatures of the fire. Its application as a cable insulation also required that the material functions as a cable insulator under ambient temperature conditions where the ceramifiable polymer composite should retain certain polymer properties such as the post-cure tensile strength (MPa), degree of polymer elongation (percent), thermal expansion, thermal slacking, limited oxygen index and electrical insulation. This study made use of a composite experimental design approach that would allow for the optimization of the amounts of the additives in the ceramifiable polymer composite giving both the desired mechanical properties of the material under normal operating temperatures as a polymer and also as a ceramic once exposed to elevated temperatures. The optimization of additives used in the ceramifiable polymer composite was done by using a D-optimal mixture design of experiments (DoE) which was analyzed by multiple linear regression.
- Full Text:
- Date Issued: 2014
An investigation on the role of Development Finance Institutions (DFI) in building small emerging enterprises for property development initiatives in South Africa
- Authors: Noholoza, Alex
- Date: 2014
- Subjects: Real estate development -- South Africa -- Finance , Entrepreneurship -- South Africa , Small business -- South Africa -- Finance
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:9714 , http://hdl.handle.net/10948/d1020646
- Description: Purpose of this treatise: The aim of this treatise is to identify the challenges facing emerging entrepreneurs in accessing funding for property development initiatives which results in high levels of declined loans thereby limiting participation in the property market as well as the interventions necessary to improve access to finance. Design / methodology / approach: The questionnaires were emailed to funding institutions and emerging property developers. The questionnaire investigates the respondents‟ perception of importance and evidence of questions on property development, finance and managerial skills drawn from the literature. Findings: The findings of this study are consistent with and support the findings of previous local and international literature on constraints that SME‟s have in accessing finance for various initiatives. The findings indicate that the emerging property developers in South Africa are characterised by insufficient number in representation in the property sector, high risk averse financial institutions that requires collateral to lend. The findings of the study indicate that broader and bolder initiatives aimed at improving the emerging property developer's representation in the market needs a holistic and collaborative approach from the various institutions to aide these entrepreneurs. Value of paper: The research is of importance to all stakeholders involved in the property sector, financial institutions and economic development of the SME sector. The results of the study will contribute to the understanding of the current financing limitations facing SMEs and will assist funding institutions to better understand the role and importance of effective collaboration in improving access to finance to emerging property developers.
- Full Text:
- Date Issued: 2014
- Authors: Noholoza, Alex
- Date: 2014
- Subjects: Real estate development -- South Africa -- Finance , Entrepreneurship -- South Africa , Small business -- South Africa -- Finance
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:9714 , http://hdl.handle.net/10948/d1020646
- Description: Purpose of this treatise: The aim of this treatise is to identify the challenges facing emerging entrepreneurs in accessing funding for property development initiatives which results in high levels of declined loans thereby limiting participation in the property market as well as the interventions necessary to improve access to finance. Design / methodology / approach: The questionnaires were emailed to funding institutions and emerging property developers. The questionnaire investigates the respondents‟ perception of importance and evidence of questions on property development, finance and managerial skills drawn from the literature. Findings: The findings of this study are consistent with and support the findings of previous local and international literature on constraints that SME‟s have in accessing finance for various initiatives. The findings indicate that the emerging property developers in South Africa are characterised by insufficient number in representation in the property sector, high risk averse financial institutions that requires collateral to lend. The findings of the study indicate that broader and bolder initiatives aimed at improving the emerging property developer's representation in the market needs a holistic and collaborative approach from the various institutions to aide these entrepreneurs. Value of paper: The research is of importance to all stakeholders involved in the property sector, financial institutions and economic development of the SME sector. The results of the study will contribute to the understanding of the current financing limitations facing SMEs and will assist funding institutions to better understand the role and importance of effective collaboration in improving access to finance to emerging property developers.
- Full Text:
- Date Issued: 2014
Analysis of the interaction between recombinant human Beta2 integrin I-domains and CD23
- Authors: Sprong, Kaitlin
- Date: 2014
- Subjects: Immune response -- Regulation , Immunoglobulins , CD23 antigen
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10362 , http://hdl.handle.net/10948/d1021078
- Description: In order to further elucidate the interaction between CD23 and β2 integrins (CD11b/CD18) the following objectives were established: Expression and purification of CD11b I-domain as a GST-fusion protein using Escherichia coli; Cloning, synthesis and expression of CD18 I-Like domain.CD11b I-domain has previously been expressed as a GST-fusion protein (Daniels, 2010) and consequently led to comparable expression of CD18 I-like domain as a GST-fusion protein; Preparation of two site-directed mutants of CD18 I-Like domain in order to study the function of the serine residue involved in the S116P mutation. The serine was mutated to proline, as in LAD patients, as well as alanine, a non-polar alternative, in order to contrast and compare binding characteristics. Expression, refolding and purification of sCD23, and a double mutatedsCD23 (RKΔAA) from E. coli; This was performed according to the method described by Daniels et al. (2005); Investigation of the CD23-CD11b I-like domain interaction through surface plasmon resonance spectroscopy.
- Full Text:
- Date Issued: 2014
- Authors: Sprong, Kaitlin
- Date: 2014
- Subjects: Immune response -- Regulation , Immunoglobulins , CD23 antigen
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10362 , http://hdl.handle.net/10948/d1021078
- Description: In order to further elucidate the interaction between CD23 and β2 integrins (CD11b/CD18) the following objectives were established: Expression and purification of CD11b I-domain as a GST-fusion protein using Escherichia coli; Cloning, synthesis and expression of CD18 I-Like domain.CD11b I-domain has previously been expressed as a GST-fusion protein (Daniels, 2010) and consequently led to comparable expression of CD18 I-like domain as a GST-fusion protein; Preparation of two site-directed mutants of CD18 I-Like domain in order to study the function of the serine residue involved in the S116P mutation. The serine was mutated to proline, as in LAD patients, as well as alanine, a non-polar alternative, in order to contrast and compare binding characteristics. Expression, refolding and purification of sCD23, and a double mutatedsCD23 (RKΔAA) from E. coli; This was performed according to the method described by Daniels et al. (2005); Investigation of the CD23-CD11b I-like domain interaction through surface plasmon resonance spectroscopy.
- Full Text:
- Date Issued: 2014
Analysis of the tectonic and basin evolution of the seychelles microcontinent during the mesozoic to cenozoic, based on seismic and well data
- Authors: Mondon, Jean-Luc Andre
- Date: 2014
- Subjects: Sedimentation and deposition , Gondwana (Continent) , Sedimentary basins
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/4386 , vital:20593
- Description: The Seychelles Microcontinent (SMc) is a fragment of continental lithosphere that experienced multiple phases of rifting and thermal subsidence during its isolation and submergence within the Indian Ocean. Originally part of central Gondwana, along with India and Madagascar, the SMc first emerged during Mesozoic fragmentation of Gondwana (ca. 220 – 180 Ma) along a complex rifted margin. Fragmentation involved three major rift phases, viz.: 1) Middle Triassic – Middle Jurassic (Rift I), associated with the “Karoo rifts” and break-up between [India-Madagascar-Seychelles] and East Africa; 2) Middle Jurassic – Early Cretaceous (Rift II), associated with the rifting and break-up of Madagascar from [India-Seychelles]; 3) Late Cretaceous (Rift III), associated with the rifting and final break-away of the SMc from India. In this study, the tectonic and sedimentary history of the SMc is analysed using 2D seismic reflection datasets and three exploration wells. Seismic to well-log correlations provide a chrono-stratigraphic framework that identifies seven sequences from the Middle Triassic to the Paleogene. This also identified horst and graben structures related to the extensional tectonics and thermal subsidence of this continental fragment. The latter is reflected also in changes of its litho-facies preserved on the SMc, from terrestrial to marine. The oldest sedimentary rocks identified on the SMc are Middle Triassic organic rich claystones (Sequence 7, Rift I), which grade upwards into alternating Upper Triassic sandstones and mudstones (Sequence 6, Rift I) followed by upward coarsening Lower Jurassic mudstones to sandstone units (Sequence 5, Rift I). These sequences are interpreted as lacustrine facies that evolved into fluvial channel migration facies and finally into progradational delta front facies. Sequence 5 is overlain by Middle Jurassic oolitic limestones that grade upwards into organic rich mudstones (Sequence 4, thermal subsidence after Rift I); the latter are interpreted as restricted-marginal marine deposits. Following Sequence 4, separated by a major break-up unconformity (BU), are the Upper Cretaceous open marine deposits comprising limestones, claystones and sandstones, and terminated with basaltic volcanics (ca. 66 Ma) prior to the separation of the SMc from India (Sequence 3, Rift III). This is overlain by the post-rift – thermal subsidence sequences comprising open marine claystones and shelf limestones (Sequence 2) followed by a sequence of shelf limestones (Sequence 1) that form the present carbonate platform, the Seychelles Plateau that lies approximately 200 m below the present sea-level. Backstripping and subsidence analysis quantifies 3 stages of subsidence; Phase A: Slow subsidence (ca. 5-20 m/Ma), from the Middle Jurassic to the Upper Cretaceous that terminated during a major marine transgression during ingression of the Tethys Sea between East Africa and [Madagascar-Seychelles-India]. This created marine conditions and the subsequent deposition of Sequences 4 and 3; Phase B: Accelerated subsidence (ca. 35-60 m/Ma) recorded throughout the Paleocene to the middle Eocene leading to deeper marine conditions and the subsequent deposition of Sequence 2; and Phase C: Reduced subsidence (ca. 10-30 m/Ma) following the interaction between the Carlsberg Ridge and the Reunion hotspot (ca. 55 Ma) that possibly introduced a reduction in subsidence and the subsequent deposition of Sequence 1 as the SMc drifted and thermally subsided to its submerged present location, and is now dominated mainly by marine carbonates. The effects of the Madagascar and Seychelles/India separation (ca. 84 Ma) are not observed in the subsidence analysis, possibly because it involved transcurrent-rotational movement between the two plates over a short period of time.
- Full Text:
- Date Issued: 2014
- Authors: Mondon, Jean-Luc Andre
- Date: 2014
- Subjects: Sedimentation and deposition , Gondwana (Continent) , Sedimentary basins
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/4386 , vital:20593
- Description: The Seychelles Microcontinent (SMc) is a fragment of continental lithosphere that experienced multiple phases of rifting and thermal subsidence during its isolation and submergence within the Indian Ocean. Originally part of central Gondwana, along with India and Madagascar, the SMc first emerged during Mesozoic fragmentation of Gondwana (ca. 220 – 180 Ma) along a complex rifted margin. Fragmentation involved three major rift phases, viz.: 1) Middle Triassic – Middle Jurassic (Rift I), associated with the “Karoo rifts” and break-up between [India-Madagascar-Seychelles] and East Africa; 2) Middle Jurassic – Early Cretaceous (Rift II), associated with the rifting and break-up of Madagascar from [India-Seychelles]; 3) Late Cretaceous (Rift III), associated with the rifting and final break-away of the SMc from India. In this study, the tectonic and sedimentary history of the SMc is analysed using 2D seismic reflection datasets and three exploration wells. Seismic to well-log correlations provide a chrono-stratigraphic framework that identifies seven sequences from the Middle Triassic to the Paleogene. This also identified horst and graben structures related to the extensional tectonics and thermal subsidence of this continental fragment. The latter is reflected also in changes of its litho-facies preserved on the SMc, from terrestrial to marine. The oldest sedimentary rocks identified on the SMc are Middle Triassic organic rich claystones (Sequence 7, Rift I), which grade upwards into alternating Upper Triassic sandstones and mudstones (Sequence 6, Rift I) followed by upward coarsening Lower Jurassic mudstones to sandstone units (Sequence 5, Rift I). These sequences are interpreted as lacustrine facies that evolved into fluvial channel migration facies and finally into progradational delta front facies. Sequence 5 is overlain by Middle Jurassic oolitic limestones that grade upwards into organic rich mudstones (Sequence 4, thermal subsidence after Rift I); the latter are interpreted as restricted-marginal marine deposits. Following Sequence 4, separated by a major break-up unconformity (BU), are the Upper Cretaceous open marine deposits comprising limestones, claystones and sandstones, and terminated with basaltic volcanics (ca. 66 Ma) prior to the separation of the SMc from India (Sequence 3, Rift III). This is overlain by the post-rift – thermal subsidence sequences comprising open marine claystones and shelf limestones (Sequence 2) followed by a sequence of shelf limestones (Sequence 1) that form the present carbonate platform, the Seychelles Plateau that lies approximately 200 m below the present sea-level. Backstripping and subsidence analysis quantifies 3 stages of subsidence; Phase A: Slow subsidence (ca. 5-20 m/Ma), from the Middle Jurassic to the Upper Cretaceous that terminated during a major marine transgression during ingression of the Tethys Sea between East Africa and [Madagascar-Seychelles-India]. This created marine conditions and the subsequent deposition of Sequences 4 and 3; Phase B: Accelerated subsidence (ca. 35-60 m/Ma) recorded throughout the Paleocene to the middle Eocene leading to deeper marine conditions and the subsequent deposition of Sequence 2; and Phase C: Reduced subsidence (ca. 10-30 m/Ma) following the interaction between the Carlsberg Ridge and the Reunion hotspot (ca. 55 Ma) that possibly introduced a reduction in subsidence and the subsequent deposition of Sequence 1 as the SMc drifted and thermally subsided to its submerged present location, and is now dominated mainly by marine carbonates. The effects of the Madagascar and Seychelles/India separation (ca. 84 Ma) are not observed in the subsidence analysis, possibly because it involved transcurrent-rotational movement between the two plates over a short period of time.
- Full Text:
- Date Issued: 2014
Biospeciation and antidiabetic effects of oxidovanadium(IV) complexes
- Authors: Ugirinema, Vital
- Date: 2014
- Subjects: Vanadium compounds , Diabetes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10442 , http://hdl.handle.net/10948/d1020973
- Description: The syntheses of bis(1R-imidazole-2/4-carboxylato)oxidovanadium(IV) complexes was successfully carried out and the complexes were isolated in the solid state. The coordinated water was confirmed by elemental analyses, and single crystal XRD. The complexes were therefore distorted octahedral rather than square planar due to the coordination of water at the sixth position. The reaction of the vanadyl ion (VO2+) with imidazole-4-carboxylic acid (Im4COOH), imidazole-2-carboxylic acid (Im2COOH) and methylimidazole-2-carboxylic acid (MeIm2COOH), respectively, in the presence of small bioligands (bL) [oxalate (Ox), lactate (Lact), and phosphate (Phos)] and high molecular weight (HMM) human serum proteins [albumin (HSA) and transferrin (hTf)] were studied in aqueous solution using potentiometric acid base titrations under oxygen and carbon dioxide–free conditions. The data obtained from these titrations was used to calculate the binary and ternary stability constants using the programme HYPERQUAD. The overall stability constants for VO2+-L-Ox system (log β1111 = 18.9, 18.79 and 19.86), VO2+-L-Lact system (log β1111 = 21.83, 20.98 and 22.86), and VO2+-L-Phos system (log β1111 = 27.35, 24.16 and 27.42) (for L= Im4COOH, Im2COOH and MeIm2COOH, respectively) were obtained. The species distribution diagrams showed that under physiological pH the following ternary and quaternary species; [(VO)L(bL)], and [VO(L)(bL)(OH)], would dominate provided that the competition with serum proteins is not too strong. These species were also confirmed by HPLC, LC-MS and EPR. The overall stability constants for the VO2+-L-HSA system (log β2,1,1,0 = 24.3, 23.7 and 24.7), and for the VO2+-L-hTf system (log β2,2,1,0 = 31.1, 30.8, 36.4 for L = Im4COOH, Im2COOH and MeIm2COOH, respectively), suggesting stronger binding of transferrin. The formation constants for the formation of binary (VO(IV) and the proteins) were 9.1 and 13 for log β11, and 20.9 and 25.2 for β12, for human serum albumin and human serum transferrin respectively. The species distribution diagrams for the proteins (HMM) with oxidovanadium(IV) under physiological pH was dominated by VO(HMM)2, VOL(HMM) for unsubstituted Im4COOH and Im2COOH, however, for the N-substituted MeIm2COOH, the species distribution diagrams under physiological pH, were dominated by VOL2, VO(HMM)2 and VO2L2(HMM). These species were further confirmed by HPLC, MALDI-TOF-MS and EPR. The glucose stimulated insulin secretion (GSIS) action of the complexes was investigated using INS-1E cells at 1μM concentration which was established through cytotoxicity studies via the MTT assay. The vanadium salt (VOSO4), cationic vanadium(IV) complex ([VO(MeImCH2OH)2]2+) were also included in the GSIS study in addition to the three neutral complexes [VO(Im4COO)2, VO(Im2COO)2 and VO(MeIm2COO)2] for comparison. The neutral complexes, especially VO(MeIm2COO)2, showed promising results in the stimulation of insulin secretion than the cationic complex and the vanadium salt.
- Full Text:
- Date Issued: 2014
- Authors: Ugirinema, Vital
- Date: 2014
- Subjects: Vanadium compounds , Diabetes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10442 , http://hdl.handle.net/10948/d1020973
- Description: The syntheses of bis(1R-imidazole-2/4-carboxylato)oxidovanadium(IV) complexes was successfully carried out and the complexes were isolated in the solid state. The coordinated water was confirmed by elemental analyses, and single crystal XRD. The complexes were therefore distorted octahedral rather than square planar due to the coordination of water at the sixth position. The reaction of the vanadyl ion (VO2+) with imidazole-4-carboxylic acid (Im4COOH), imidazole-2-carboxylic acid (Im2COOH) and methylimidazole-2-carboxylic acid (MeIm2COOH), respectively, in the presence of small bioligands (bL) [oxalate (Ox), lactate (Lact), and phosphate (Phos)] and high molecular weight (HMM) human serum proteins [albumin (HSA) and transferrin (hTf)] were studied in aqueous solution using potentiometric acid base titrations under oxygen and carbon dioxide–free conditions. The data obtained from these titrations was used to calculate the binary and ternary stability constants using the programme HYPERQUAD. The overall stability constants for VO2+-L-Ox system (log β1111 = 18.9, 18.79 and 19.86), VO2+-L-Lact system (log β1111 = 21.83, 20.98 and 22.86), and VO2+-L-Phos system (log β1111 = 27.35, 24.16 and 27.42) (for L= Im4COOH, Im2COOH and MeIm2COOH, respectively) were obtained. The species distribution diagrams showed that under physiological pH the following ternary and quaternary species; [(VO)L(bL)], and [VO(L)(bL)(OH)], would dominate provided that the competition with serum proteins is not too strong. These species were also confirmed by HPLC, LC-MS and EPR. The overall stability constants for the VO2+-L-HSA system (log β2,1,1,0 = 24.3, 23.7 and 24.7), and for the VO2+-L-hTf system (log β2,2,1,0 = 31.1, 30.8, 36.4 for L = Im4COOH, Im2COOH and MeIm2COOH, respectively), suggesting stronger binding of transferrin. The formation constants for the formation of binary (VO(IV) and the proteins) were 9.1 and 13 for log β11, and 20.9 and 25.2 for β12, for human serum albumin and human serum transferrin respectively. The species distribution diagrams for the proteins (HMM) with oxidovanadium(IV) under physiological pH was dominated by VO(HMM)2, VOL(HMM) for unsubstituted Im4COOH and Im2COOH, however, for the N-substituted MeIm2COOH, the species distribution diagrams under physiological pH, were dominated by VOL2, VO(HMM)2 and VO2L2(HMM). These species were further confirmed by HPLC, MALDI-TOF-MS and EPR. The glucose stimulated insulin secretion (GSIS) action of the complexes was investigated using INS-1E cells at 1μM concentration which was established through cytotoxicity studies via the MTT assay. The vanadium salt (VOSO4), cationic vanadium(IV) complex ([VO(MeImCH2OH)2]2+) were also included in the GSIS study in addition to the three neutral complexes [VO(Im4COO)2, VO(Im2COO)2 and VO(MeIm2COO)2] for comparison. The neutral complexes, especially VO(MeIm2COO)2, showed promising results in the stimulation of insulin secretion than the cationic complex and the vanadium salt.
- Full Text:
- Date Issued: 2014
Causes and effects of non-payment of residential property rates in Mahikeng
- Authors: Asianoah, Rexford Kofi
- Date: 2014
- Subjects: Debts, Public -- South Africa -- Mahikeng , Municipal default -- South Africa -- Mahikeng , Public utilities -- South Africa -- Mahikeng , Collecting of accounts -- South Africa -- Mahikeng
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:9674 , http://hdl.handle.net/10948/d1020076
- Description: One of the major sources of income to South African Municipalities is property rates. Income generated from property rates is meant to develop and deliver services to residents living in the said Municipal area. The main aim of the research was to identify the causes and effects of the non-payment of residential property rates, and also to develop workable strategies to maximise the collection of residential property rates in order to ensure developmental growth sustenance, specifically in Mahikeng Municipal area. Related literature was reviewed on the non-financial viability of Municipalities, maintenance of public infrastructure, service delivery and Municipal development plans in establishing the relationship with non-payment of residential property rates. Four hypotheses were set to guide the research with two testing positive with high level of confidence using the chi square method of testing. The research methodology employed in the research was mainly quantitative where the results and findings obtained from the questionnaire were statistically analysed. The research revealed that: The Mahikeng Local Municipality has failed to find the right medium to send rates bills to clients on time, is not taking active responsibility to recover rates debts, does not provide quality service delivery and the reluctance by locals to pay their property rates. The effects thereof, are the inability of the Municipality to deliver effective and efficient services, lack of maintenance of public infrastructure and development in the area. By implementing various options such as email, sms and the post to send rates bills to property owners, by employing different payment options, for example debit orders, transfers, bank deposits and discounts for property owners and embarking on periodic public awareness campaigns in educating the community regarding the importance of payment of property rates could serve as effective mechanisms to address the non-payment of residential property rates faced by the Mahikeng Local Municipality.
- Full Text:
- Date Issued: 2014
- Authors: Asianoah, Rexford Kofi
- Date: 2014
- Subjects: Debts, Public -- South Africa -- Mahikeng , Municipal default -- South Africa -- Mahikeng , Public utilities -- South Africa -- Mahikeng , Collecting of accounts -- South Africa -- Mahikeng
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:9674 , http://hdl.handle.net/10948/d1020076
- Description: One of the major sources of income to South African Municipalities is property rates. Income generated from property rates is meant to develop and deliver services to residents living in the said Municipal area. The main aim of the research was to identify the causes and effects of the non-payment of residential property rates, and also to develop workable strategies to maximise the collection of residential property rates in order to ensure developmental growth sustenance, specifically in Mahikeng Municipal area. Related literature was reviewed on the non-financial viability of Municipalities, maintenance of public infrastructure, service delivery and Municipal development plans in establishing the relationship with non-payment of residential property rates. Four hypotheses were set to guide the research with two testing positive with high level of confidence using the chi square method of testing. The research methodology employed in the research was mainly quantitative where the results and findings obtained from the questionnaire were statistically analysed. The research revealed that: The Mahikeng Local Municipality has failed to find the right medium to send rates bills to clients on time, is not taking active responsibility to recover rates debts, does not provide quality service delivery and the reluctance by locals to pay their property rates. The effects thereof, are the inability of the Municipality to deliver effective and efficient services, lack of maintenance of public infrastructure and development in the area. By implementing various options such as email, sms and the post to send rates bills to property owners, by employing different payment options, for example debit orders, transfers, bank deposits and discounts for property owners and embarking on periodic public awareness campaigns in educating the community regarding the importance of payment of property rates could serve as effective mechanisms to address the non-payment of residential property rates faced by the Mahikeng Local Municipality.
- Full Text:
- Date Issued: 2014
Characterization of animal fibres
- Authors: Notayi, Mzwamadoda
- Date: 2014
- Subjects: Animal fibres , Textile fabrics , Animal science
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10552 , http://hdl.handle.net/10948/d1020426
- Description: Identification of fibres, particularly in blends, requires knowledge of their characteristics. Individual Identifying features between wool and mohair fibres were investigated in this study using a Scanning Electron Microscope (SEM), Fourier Transform Infrared-Attenuated Total Reflection (FTIR-ATR), Fourier Transform Raman and Atomic Force Microscope (AFM). This study confirmed that wool and mohair can be differentiated and identified in blends using the cuticle scale height (CSH) criterion, wool having an average CSH of 0.6 ± 0.1 μm and mohair having an average CSH of 0.4 ± 0.1 μm. The AFM provided highly reproducible CSH results, which also confirmed the SEM results that indeed wool and mohair could be differentiated using the CSH as criterion. The AFM gave a CSH value of 0.9 ± 0.2 μm for wool and 0.6 ± 0.2 μm for mohair, the difference between the two results being statistically significant according to the student t-test. It has been demonstrated that wool and mohair identification in blends is possible, by using the AFM to measure CSH, although the method is very time consuming and might be expensive. The FTIR-ATR showed similar spectra for wool and mohair fibres, confirming that the two fibre types consist of the same polymer material. Nevertheless, a difference was observed in the ratios of the relative intensities of the amide I (around 1630 cm-1) to the amide II (around 1515cm-1) absorption bands. The FT Raman provided similar spectra for the wool and mohair fibres, although a possible distinguishing feature between the two fibres could be the intensities of the alkyl side chains chemical band near 2940 cm-1 in the spectra of the two fibre types. According to the results obtained in this study, the FTIR-ATR and the FT Raman techniques may have potential for differentiating between wool and mohair but this requires further investigation.
- Full Text:
- Date Issued: 2014
- Authors: Notayi, Mzwamadoda
- Date: 2014
- Subjects: Animal fibres , Textile fabrics , Animal science
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10552 , http://hdl.handle.net/10948/d1020426
- Description: Identification of fibres, particularly in blends, requires knowledge of their characteristics. Individual Identifying features between wool and mohair fibres were investigated in this study using a Scanning Electron Microscope (SEM), Fourier Transform Infrared-Attenuated Total Reflection (FTIR-ATR), Fourier Transform Raman and Atomic Force Microscope (AFM). This study confirmed that wool and mohair can be differentiated and identified in blends using the cuticle scale height (CSH) criterion, wool having an average CSH of 0.6 ± 0.1 μm and mohair having an average CSH of 0.4 ± 0.1 μm. The AFM provided highly reproducible CSH results, which also confirmed the SEM results that indeed wool and mohair could be differentiated using the CSH as criterion. The AFM gave a CSH value of 0.9 ± 0.2 μm for wool and 0.6 ± 0.2 μm for mohair, the difference between the two results being statistically significant according to the student t-test. It has been demonstrated that wool and mohair identification in blends is possible, by using the AFM to measure CSH, although the method is very time consuming and might be expensive. The FTIR-ATR showed similar spectra for wool and mohair fibres, confirming that the two fibre types consist of the same polymer material. Nevertheless, a difference was observed in the ratios of the relative intensities of the amide I (around 1630 cm-1) to the amide II (around 1515cm-1) absorption bands. The FT Raman provided similar spectra for the wool and mohair fibres, although a possible distinguishing feature between the two fibres could be the intensities of the alkyl side chains chemical band near 2940 cm-1 in the spectra of the two fibre types. According to the results obtained in this study, the FTIR-ATR and the FT Raman techniques may have potential for differentiating between wool and mohair but this requires further investigation.
- Full Text:
- Date Issued: 2014
Characterization of chromatic dispersion in single mode fibre
- Authors: Wassin, Shukree
- Date: 2014
- Subjects: Fiber optics Electromagnetic waves , Electromagnetic waves -- Transmission
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/47807 , vital:40379
- Description: In this dissertation, an investigation of chromatic dispersion is presented. The Pulse delay and phase Shift chromatic dispersion characterization techniques were used for conducting the measurements. The experiments were performed in a modern optical fibre research laboratory and chromatic dispersion measurements were carried out on several lengths of G.652 and G.655 single mode fibres. The pulse delay characterization technique measures the time of flight between two modulated optical signals whilst propagating along the fibre under test. During phase shift experiments, the group delay is obtained by measuring the relative phase difference as a function of wavelength, between adjacent sinusoidal light signals. The pulse delay and phase shift characterization techniques illustrated excellent agreement in the measured! chromatic Dispersion coefficients along the G.652 standard single mode! fibre as well as the G.655 positive and negative non-zero dispersion shifted fibre. It was found that the measurement accuracy improved as the fibre length increased. A periodic shift between the modulated optical signals, propagating along the fibre was experimentally observed. It is to be remarked that the longer wavelength signals propagated faster along the G.655 positive non-zero dispersion shifted fibre in comparison to its transmission within the G.655 negative non-zero dispersion shifted fibre. Furthermore, it was found that the sinusoidal signal shifted towards the left along the G.655 negative NZDSF fibre whilst the shift occurred towards the right along the G.655 positive NZDSF fibre. Generally, the shift arising along the G.655 fibres was found to be smaller than the shift seen throughout the G.652 fibres. Towards the end of this study, a chromatic dispersion compensation system was designed and tested. Once characterization of the compensation link was completed, it was experimentally illustrated that the chromatic dispersion across the system was successfully reduced. Finally, a sum of squares of error statistical test showed that the phase shift technique is more accurate in comparison to the pulse delay method. This result was found to be in good agreement with published work found in literature.
- Full Text:
- Date Issued: 2014
- Authors: Wassin, Shukree
- Date: 2014
- Subjects: Fiber optics Electromagnetic waves , Electromagnetic waves -- Transmission
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/47807 , vital:40379
- Description: In this dissertation, an investigation of chromatic dispersion is presented. The Pulse delay and phase Shift chromatic dispersion characterization techniques were used for conducting the measurements. The experiments were performed in a modern optical fibre research laboratory and chromatic dispersion measurements were carried out on several lengths of G.652 and G.655 single mode fibres. The pulse delay characterization technique measures the time of flight between two modulated optical signals whilst propagating along the fibre under test. During phase shift experiments, the group delay is obtained by measuring the relative phase difference as a function of wavelength, between adjacent sinusoidal light signals. The pulse delay and phase shift characterization techniques illustrated excellent agreement in the measured! chromatic Dispersion coefficients along the G.652 standard single mode! fibre as well as the G.655 positive and negative non-zero dispersion shifted fibre. It was found that the measurement accuracy improved as the fibre length increased. A periodic shift between the modulated optical signals, propagating along the fibre was experimentally observed. It is to be remarked that the longer wavelength signals propagated faster along the G.655 positive non-zero dispersion shifted fibre in comparison to its transmission within the G.655 negative non-zero dispersion shifted fibre. Furthermore, it was found that the sinusoidal signal shifted towards the left along the G.655 negative NZDSF fibre whilst the shift occurred towards the right along the G.655 positive NZDSF fibre. Generally, the shift arising along the G.655 fibres was found to be smaller than the shift seen throughout the G.652 fibres. Towards the end of this study, a chromatic dispersion compensation system was designed and tested. Once characterization of the compensation link was completed, it was experimentally illustrated that the chromatic dispersion across the system was successfully reduced. Finally, a sum of squares of error statistical test showed that the phase shift technique is more accurate in comparison to the pulse delay method. This result was found to be in good agreement with published work found in literature.
- Full Text:
- Date Issued: 2014
Contemporary use and seasonal abundance of indigenous edible plants (with an emphasis on geophytes) available to human foragers on the Cape south coast, South Africa
- Authors: De Vynck, Jan Carlo
- Date: 2014
- Subjects: Wild plants, Edible -- Africa, Southern , Coastal plants -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10638 , http://hdl.handle.net/10948/d1020044
- Description: Human subsistence within the Cape Floristic Region (Cape) dates back to our inception as a distinct species. Unique archaeological evidence found here for the defining attribute of cognitive modernity, as well as coinciding paleo-climatic challenges to survival, both highlight the Cape’s potential to support the existence of pre-historic hunter-gatherers. This habitat, with its unprecedented diversity of geophytes and other plant growth forms, has not yet revealed its potential to provide carbohydrate resources for early Homo sapiens sapiens. In order to investigate this potential, an ethnobotanical survey of the south Cape coastal area near Still Bay was conducted. Despite 17th Century colonialism marking the onset of indigenous plant knowledge decline, the 18 people of Khoe-San descent interviewed in this survey still actively used 58 indigenous edible plant species with a variety of 69 uses. Fruit showed the highest popularity of plants used (52 percent) followed by nectar, with plants having underground storage organs (USOs) ranking third (34 percent). Among growth forms, shrubs dominated (34 percent) followed by geophytes and trees (both 21 percent). With the exception of Prionium serratum, which was rare in the research area, this study failed to identify species that could have formed a staple source of carbohydrate for pre-colonial Khoe-San peoples of the Cape south coast. While eight species of USOs were identified (12 percent of total) only Cyphia species emerged as an important carbohydrate source. This study indicated the importance of Thicket Biome species as a source of edible plants. The second component of the study comprised a two year phenological survey of indigenous edible plant species in four primary vegetation types. A total of 32 USO species and 21 species with aboveground edible carbohydrates (fruiting species) were identified across all sites. Limestone Fynbos had the richest flora of edible species (21 USO species and 18 fruiting species), followed by Strandveld (15 USOs and 13 fruiting species), Renosterveld (8 and 8, respectively) and lastly Sand Fynbos (5 and 5, respectively). The season of highest apparency showed slight variation amongst the four sites over the two years, with more variation evident in the period of apparency. The first survey year had below average rainfall, while the second year received an average rainfall amount. The second year saw a dramatic increase in apparency of abundance for all sites (50 to 60 percent increase) except for the Sand Fynbos site, which showed little change. The other sites showed a one month increase in the period of apparency in the second survey year. Overall, late summer to autumn was the period of lowest apparency of USOs. The ripening of certain fruiting species during this time would have provided a source of carbohydrate when USO availability was at its lowest. Strandveld had the highest biomass in the peak of apparency (over 80 kgha-1) in the first year with a nearly 20 percent increase for the second year. The combined biomass for the four study sites in the first survey year was roughly 150 kgha-1 and 185 kgha-1 for the second year. The apparency of abundance (ripe and edible phase) of fruiting species did not increase much for Renosterveld and Strandveld in the second survey year, except for Limestone Fynbos (49 percent increase) and Sand Fynbos (53 percent). A multivariate analysis showed seven phenophases for high apparency of edible USOs and ripe fruit across the four vegetation types. Given the contribution of evergreen USOs and fruiting species, there would always have been carbohydrates available for foragers to collect in the major vegetation types of the south Cape coast. However, harvesting and processing this carbohydrate resource would have posed cognitive challenges for MSA hunter-gatherers, given the interwoven taxonomic complexity of numerous toxic plant species, and the diverse phenology of edible plant species within the varied vegetation types. These challenges were undoubtedly mastered, highlighting the Cape environment as a possible catalyst to improved human cognitive maturity.
- Full Text:
- Date Issued: 2014
- Authors: De Vynck, Jan Carlo
- Date: 2014
- Subjects: Wild plants, Edible -- Africa, Southern , Coastal plants -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10638 , http://hdl.handle.net/10948/d1020044
- Description: Human subsistence within the Cape Floristic Region (Cape) dates back to our inception as a distinct species. Unique archaeological evidence found here for the defining attribute of cognitive modernity, as well as coinciding paleo-climatic challenges to survival, both highlight the Cape’s potential to support the existence of pre-historic hunter-gatherers. This habitat, with its unprecedented diversity of geophytes and other plant growth forms, has not yet revealed its potential to provide carbohydrate resources for early Homo sapiens sapiens. In order to investigate this potential, an ethnobotanical survey of the south Cape coastal area near Still Bay was conducted. Despite 17th Century colonialism marking the onset of indigenous plant knowledge decline, the 18 people of Khoe-San descent interviewed in this survey still actively used 58 indigenous edible plant species with a variety of 69 uses. Fruit showed the highest popularity of plants used (52 percent) followed by nectar, with plants having underground storage organs (USOs) ranking third (34 percent). Among growth forms, shrubs dominated (34 percent) followed by geophytes and trees (both 21 percent). With the exception of Prionium serratum, which was rare in the research area, this study failed to identify species that could have formed a staple source of carbohydrate for pre-colonial Khoe-San peoples of the Cape south coast. While eight species of USOs were identified (12 percent of total) only Cyphia species emerged as an important carbohydrate source. This study indicated the importance of Thicket Biome species as a source of edible plants. The second component of the study comprised a two year phenological survey of indigenous edible plant species in four primary vegetation types. A total of 32 USO species and 21 species with aboveground edible carbohydrates (fruiting species) were identified across all sites. Limestone Fynbos had the richest flora of edible species (21 USO species and 18 fruiting species), followed by Strandveld (15 USOs and 13 fruiting species), Renosterveld (8 and 8, respectively) and lastly Sand Fynbos (5 and 5, respectively). The season of highest apparency showed slight variation amongst the four sites over the two years, with more variation evident in the period of apparency. The first survey year had below average rainfall, while the second year received an average rainfall amount. The second year saw a dramatic increase in apparency of abundance for all sites (50 to 60 percent increase) except for the Sand Fynbos site, which showed little change. The other sites showed a one month increase in the period of apparency in the second survey year. Overall, late summer to autumn was the period of lowest apparency of USOs. The ripening of certain fruiting species during this time would have provided a source of carbohydrate when USO availability was at its lowest. Strandveld had the highest biomass in the peak of apparency (over 80 kgha-1) in the first year with a nearly 20 percent increase for the second year. The combined biomass for the four study sites in the first survey year was roughly 150 kgha-1 and 185 kgha-1 for the second year. The apparency of abundance (ripe and edible phase) of fruiting species did not increase much for Renosterveld and Strandveld in the second survey year, except for Limestone Fynbos (49 percent increase) and Sand Fynbos (53 percent). A multivariate analysis showed seven phenophases for high apparency of edible USOs and ripe fruit across the four vegetation types. Given the contribution of evergreen USOs and fruiting species, there would always have been carbohydrates available for foragers to collect in the major vegetation types of the south Cape coast. However, harvesting and processing this carbohydrate resource would have posed cognitive challenges for MSA hunter-gatherers, given the interwoven taxonomic complexity of numerous toxic plant species, and the diverse phenology of edible plant species within the varied vegetation types. These challenges were undoubtedly mastered, highlighting the Cape environment as a possible catalyst to improved human cognitive maturity.
- Full Text:
- Date Issued: 2014
Developing an understanding of the drivers of bat activity patterns relevant to wind turbines
- Authors: Thwaits, Tiffany Edan
- Date: 2014
- Subjects: Bats -- Behavior -- Climatic factors -- South Africa , Bats -- Ecology -- South Africa -- Eastern Cape , Wind power -- Environmental aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10726 , http://hdl.handle.net/10948/d1020970
- Description: The increasing number of proposed wind farm developments in South Africa provides an immediate reason to assess bat activity and diversity, with the expectation of developing measures to mitigate for negative impacts. The overall aim of this thesis was contribute to an understanding of the drivers of bat activity, relevant to wind turbines, and to determine what factors (exogenous – environmental, or endogenous – intrinsic physiological processes) contributed to observed bat activity patterns, at the Metrowind Van Stadens Wind Farm in the Eastern Cape of South Africa. A combination of active (mist netting) and passive (acoustic) bat monitoring techniques were used to determine free-ranging bat activity patterns (Chapter 3). A total of 889 bat passes were recorded over 323 detector nights from the beginning of May 2012 to the end of December 2012. The Cape serotine bat (82 per cent) and the Egyptian free-tailed bat (97 per cent) made up the majority of all bat passes recorded on site. Large variations in bat activity per month and per hour were apparent, with bat activity peaking in May 2012 and during the first few hours after sunset (18:00-23:00). Patterns in nightly, free-ranging bat activity at the site were modelled against various environmental conditions. Month, temperature, wind speed and an interaction between month and rainfall were the most significant predictors of bat activity, explaining 80 per cent of the variation observed on free-ranging bat activity patterns. A total of eight Cape serotine bats (Table 4.1.) were caught in mist nets on site and changes in the resting metabolic rate (RMR) of torpid (n = 6), and normothermic (n = 2) bats, over a 24 hr period, were measured and used to predict free-ranging Cape serotine bat activity (Chapter 4). Cape serotine bats showed a high proclivity for torpor in the laboratory and peaks in RMR were observed at 18:00 (0.89 ± 0.95 VO2 mℓ.g-1.hr-1) and again from 20:00-21:00 (0.89 ± 0.91 VO2 mℓ.g-1.hr-1). Peaks in RMR of torpid individuals coincided with peaks in the average hourly free-ranging activity of the Cape serotine bat, and RMR explained 33 per cent of the variation and was a good predictor of free-ranging bat activity (R2 = 0.2914). This study showed that both exogenous (Chapter 3) and endogenous (Chapter 4) factors drive bat activity in the wild. Although this dissertation was not intended for wind turbine management, the information presented on the biology and activity of bats is important for managing interactions between bats and wind turbines. By determining what factors influence bat activity, we are able to predict when bats will be most active and thus can develop mitigation measures to reduce the potential impacts that wind turbines will have on the bat community. In order to conserve bats and reduce potential bat fatalities from occurring at the site, mitigation measures should be concentrated to those times when bats are most active (May and during the first few hours after sunset – 18:00 to 22:00).
- Full Text:
- Date Issued: 2014
- Authors: Thwaits, Tiffany Edan
- Date: 2014
- Subjects: Bats -- Behavior -- Climatic factors -- South Africa , Bats -- Ecology -- South Africa -- Eastern Cape , Wind power -- Environmental aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10726 , http://hdl.handle.net/10948/d1020970
- Description: The increasing number of proposed wind farm developments in South Africa provides an immediate reason to assess bat activity and diversity, with the expectation of developing measures to mitigate for negative impacts. The overall aim of this thesis was contribute to an understanding of the drivers of bat activity, relevant to wind turbines, and to determine what factors (exogenous – environmental, or endogenous – intrinsic physiological processes) contributed to observed bat activity patterns, at the Metrowind Van Stadens Wind Farm in the Eastern Cape of South Africa. A combination of active (mist netting) and passive (acoustic) bat monitoring techniques were used to determine free-ranging bat activity patterns (Chapter 3). A total of 889 bat passes were recorded over 323 detector nights from the beginning of May 2012 to the end of December 2012. The Cape serotine bat (82 per cent) and the Egyptian free-tailed bat (97 per cent) made up the majority of all bat passes recorded on site. Large variations in bat activity per month and per hour were apparent, with bat activity peaking in May 2012 and during the first few hours after sunset (18:00-23:00). Patterns in nightly, free-ranging bat activity at the site were modelled against various environmental conditions. Month, temperature, wind speed and an interaction between month and rainfall were the most significant predictors of bat activity, explaining 80 per cent of the variation observed on free-ranging bat activity patterns. A total of eight Cape serotine bats (Table 4.1.) were caught in mist nets on site and changes in the resting metabolic rate (RMR) of torpid (n = 6), and normothermic (n = 2) bats, over a 24 hr period, were measured and used to predict free-ranging Cape serotine bat activity (Chapter 4). Cape serotine bats showed a high proclivity for torpor in the laboratory and peaks in RMR were observed at 18:00 (0.89 ± 0.95 VO2 mℓ.g-1.hr-1) and again from 20:00-21:00 (0.89 ± 0.91 VO2 mℓ.g-1.hr-1). Peaks in RMR of torpid individuals coincided with peaks in the average hourly free-ranging activity of the Cape serotine bat, and RMR explained 33 per cent of the variation and was a good predictor of free-ranging bat activity (R2 = 0.2914). This study showed that both exogenous (Chapter 3) and endogenous (Chapter 4) factors drive bat activity in the wild. Although this dissertation was not intended for wind turbine management, the information presented on the biology and activity of bats is important for managing interactions between bats and wind turbines. By determining what factors influence bat activity, we are able to predict when bats will be most active and thus can develop mitigation measures to reduce the potential impacts that wind turbines will have on the bat community. In order to conserve bats and reduce potential bat fatalities from occurring at the site, mitigation measures should be concentrated to those times when bats are most active (May and during the first few hours after sunset – 18:00 to 22:00).
- Full Text:
- Date Issued: 2014
Development of polymer templates for ZnO nanorods
- Authors: Dobson, Stephen Robert
- Date: 2014
- Subjects: Polymers , Semiconductor industry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10556 , http://hdl.handle.net/10948/d1020805
- Description: One of the biggest challenges for the semiconductor industry is the development of nanofabrication techniques that allow for the fabrication of structures on a scale tens of nanometers in size. This provides greater potential functionality at reduced costs. Established conventional techniques, such as photolithography, are unable to achieve features below 30 nm due to the inherent limitations of the wavelength of light sources currently available. For this reason block copolymers received considerable attention in order to overcome these challenges in lithographic technology. Block copolymers have an inherent processing advantage of self assembling into various nanoscopic structures such as spheres, cylinders and lamellae amongst others on a scale below 50 nm. The dimensions and structures are readily tuneable based on molecular weights (Mw) and compositions of the copolymers. However, to be usable within industry a great deal more research still needs to be conducted on the use and nature of block copolymers. In this study the block copolymer of poly(styrene-block-methylmethacrylate) (PS-b-PMMA) was investigated as a potential nano-mask for semiconductor growth. Research was conducted on thin films of PS-b-PMMA by altering the parameters influencing the kinetics and thermodynamic effects on the thin films, in order to produce a structure of cylinders of PMMA perpendicular to the substrate within a PS matrix on a silicon (Si) substrate. It is shown that thermally annealing the PS-b-PMMA thin films under conditions where there is no preferential interaction of the substrate or open surface with either components of the block copolymer (i.e. PS or PMMA with Si or ambient) and at an appropriate thin film thickness, perpendicular cylinders of PMMA within a PS matrix form in the thin films. The determined ideal thin film thickness is 32 nm, with non-preferential interaction attained between block and substrate by coating a poly(styrene-random-methylmethacrylate) (PS-r-PMMA) on the Si substrate and annealing within a vacuum. Additionally, acetic acid, as a known selective solvent of PMMA, is used to further process the thin film of PS-b-PMMA. Thus a final PS nano-mask containing pores with a diameter tens of nanometers in size is produced. The pores are shown to have an average diameter of 13.5 nm. Measurements were taken throughout the investigation using a scanning probe microscope (SPM) to determine surface topography and phase morphology of the PS-b-PMMA thin films. X-ray reflectometry (XRR) is used to measure film thickness. The research in this study shows that thin films of PS containing hexagonally arranged pores can be produced and could find potential use as a nano-mask for semiconductor growth.
- Full Text:
- Date Issued: 2014
- Authors: Dobson, Stephen Robert
- Date: 2014
- Subjects: Polymers , Semiconductor industry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10556 , http://hdl.handle.net/10948/d1020805
- Description: One of the biggest challenges for the semiconductor industry is the development of nanofabrication techniques that allow for the fabrication of structures on a scale tens of nanometers in size. This provides greater potential functionality at reduced costs. Established conventional techniques, such as photolithography, are unable to achieve features below 30 nm due to the inherent limitations of the wavelength of light sources currently available. For this reason block copolymers received considerable attention in order to overcome these challenges in lithographic technology. Block copolymers have an inherent processing advantage of self assembling into various nanoscopic structures such as spheres, cylinders and lamellae amongst others on a scale below 50 nm. The dimensions and structures are readily tuneable based on molecular weights (Mw) and compositions of the copolymers. However, to be usable within industry a great deal more research still needs to be conducted on the use and nature of block copolymers. In this study the block copolymer of poly(styrene-block-methylmethacrylate) (PS-b-PMMA) was investigated as a potential nano-mask for semiconductor growth. Research was conducted on thin films of PS-b-PMMA by altering the parameters influencing the kinetics and thermodynamic effects on the thin films, in order to produce a structure of cylinders of PMMA perpendicular to the substrate within a PS matrix on a silicon (Si) substrate. It is shown that thermally annealing the PS-b-PMMA thin films under conditions where there is no preferential interaction of the substrate or open surface with either components of the block copolymer (i.e. PS or PMMA with Si or ambient) and at an appropriate thin film thickness, perpendicular cylinders of PMMA within a PS matrix form in the thin films. The determined ideal thin film thickness is 32 nm, with non-preferential interaction attained between block and substrate by coating a poly(styrene-random-methylmethacrylate) (PS-r-PMMA) on the Si substrate and annealing within a vacuum. Additionally, acetic acid, as a known selective solvent of PMMA, is used to further process the thin film of PS-b-PMMA. Thus a final PS nano-mask containing pores with a diameter tens of nanometers in size is produced. The pores are shown to have an average diameter of 13.5 nm. Measurements were taken throughout the investigation using a scanning probe microscope (SPM) to determine surface topography and phase morphology of the PS-b-PMMA thin films. X-ray reflectometry (XRR) is used to measure film thickness. The research in this study shows that thin films of PS containing hexagonally arranged pores can be produced and could find potential use as a nano-mask for semiconductor growth.
- Full Text:
- Date Issued: 2014
Electrical conductivity experiments on carbon-rich Karoo shales and forward modelling of aeromagnetic data across the Beattie Anomaly
- Authors: Branch, Thomas Cameron
- Date: 2014
- Subjects: Earth sciences -- South Africa -- Karoo , Geology -- South Africa -- Karoo
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10662 , http://hdl.handle.net/10948/d1014544
- Description: The Beattie Magnetic Anomaly is the world’s longest terrestrial magnetic anomaly with a strike length of over 1000 km and a wavelength in excess of 100 km. Collinear with this is a large belt of elevated crustal conductivities called the Southern Cape Conductive Belt. Historical crustal interpretations proposed a common source of serpentinized ophiolite as an explanation for both the anomalous crustal magnetic susceptibility and electrical conductivities. Spreading between the Western and Eastern Cape of South Africa the mid- to lower crust that hosts these anomalies is obscured by the overlying Cape and Karoo Supergroups. Between 2003 and 2006, three high resolution geophysical experiments were completed across the surface maximum of the Beattie Magnetic Anomaly (BMA) and the Southern Cape Conductive Belt (SCCB). These included a magnetotelluric (MT) survey and near vertical reflection and wide angle refraction seismic profiles. Within the MT inversion model the SCCB appeared as a composite anomaly, which included a mid-crustal conductor which is spatially associated with the BMA and a laterally continuous upper crustal conductor which is located at depths equivalent to the lower Karoo Supergroup. Subsequently; the upper crustal conductor was identified in northern and eastern extensions of the magnetotelluric profile; a distance in excess of 400 km. Historical magnetometer and Schlumberger Sounding experiments have previously identified elevated conductivities in the Karoo sequences which were attributed to the Whitehill and Prince Albert formations. These carboniferous, transgressive sediments are known to be conductive from borehole conductivity surveys and direct measurements at surface. In order to constrain the conductive properties of these sediments, impedance spectroscopy (IS) experiments were completed on core samples collected from a historical borehole drilled near to the MT profile. Part One of this thesis presents the results of these experiments, which support the proposition that the Whitehill and Prince Albert Formations are responsible for the laterally continuous, sub-horizontal, upper crustal conductor visible in the MT inversion model. Vitrinite reflectance studies were performed on the same samples by the Montanuniversität, in Leoben, these results corroborate the proposition that elevated organic carbon, of meta-anthracite rank, is the primary conductive phase for the Whitehill and Prince Albert formations. Part two of this thesis completed forward modelling exercises using historical aeromagnetic data previously collected across the Beattie Magnetic Anomaly. Preliminary models were unable to fit the geometry of any single magnetic model with conductors present in the MT inversion model discounting the proposition that the SCCB and BMA arise from a single crustal unit. Two constrained models were arrived at through an iterative process that sought a best fit between the measured data and the NVR crustal interpretations. The first model, proposes a largely resistive unit which incorporates portions of elevated crustal conductivity; these conductors are spatially correlated to crustal portions also characterised by high seismic reflectivity. The size of this modelled body suggest the likely host of the BMA is an intermediate plutonic terrane, analogous with the Natal sector of the Namaqua Natal Mobile Belt as well as the Heimefrontfjella in Dronning Maud Land, Antarctica, with magnetite hosted within shear zones. This is in agreement with previous studies. The second model proposes a lower crustal sliver imaged in the NVR data at depths proximal to the Curie Isotherm for magnetite and hematite as the source of the BMA. At these depths geomagnetic properties such as burial magnetisation or thermo-viscous remanent magnetism (TVRM) can potentially be linked to regional scale tectonic processes and can theoretically elevate a body’s net magnetic susceptibility. TVRM has been proposed for long wavelength crustal anomalies elsewhere.
- Full Text:
- Date Issued: 2014
- Authors: Branch, Thomas Cameron
- Date: 2014
- Subjects: Earth sciences -- South Africa -- Karoo , Geology -- South Africa -- Karoo
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10662 , http://hdl.handle.net/10948/d1014544
- Description: The Beattie Magnetic Anomaly is the world’s longest terrestrial magnetic anomaly with a strike length of over 1000 km and a wavelength in excess of 100 km. Collinear with this is a large belt of elevated crustal conductivities called the Southern Cape Conductive Belt. Historical crustal interpretations proposed a common source of serpentinized ophiolite as an explanation for both the anomalous crustal magnetic susceptibility and electrical conductivities. Spreading between the Western and Eastern Cape of South Africa the mid- to lower crust that hosts these anomalies is obscured by the overlying Cape and Karoo Supergroups. Between 2003 and 2006, three high resolution geophysical experiments were completed across the surface maximum of the Beattie Magnetic Anomaly (BMA) and the Southern Cape Conductive Belt (SCCB). These included a magnetotelluric (MT) survey and near vertical reflection and wide angle refraction seismic profiles. Within the MT inversion model the SCCB appeared as a composite anomaly, which included a mid-crustal conductor which is spatially associated with the BMA and a laterally continuous upper crustal conductor which is located at depths equivalent to the lower Karoo Supergroup. Subsequently; the upper crustal conductor was identified in northern and eastern extensions of the magnetotelluric profile; a distance in excess of 400 km. Historical magnetometer and Schlumberger Sounding experiments have previously identified elevated conductivities in the Karoo sequences which were attributed to the Whitehill and Prince Albert formations. These carboniferous, transgressive sediments are known to be conductive from borehole conductivity surveys and direct measurements at surface. In order to constrain the conductive properties of these sediments, impedance spectroscopy (IS) experiments were completed on core samples collected from a historical borehole drilled near to the MT profile. Part One of this thesis presents the results of these experiments, which support the proposition that the Whitehill and Prince Albert Formations are responsible for the laterally continuous, sub-horizontal, upper crustal conductor visible in the MT inversion model. Vitrinite reflectance studies were performed on the same samples by the Montanuniversität, in Leoben, these results corroborate the proposition that elevated organic carbon, of meta-anthracite rank, is the primary conductive phase for the Whitehill and Prince Albert formations. Part two of this thesis completed forward modelling exercises using historical aeromagnetic data previously collected across the Beattie Magnetic Anomaly. Preliminary models were unable to fit the geometry of any single magnetic model with conductors present in the MT inversion model discounting the proposition that the SCCB and BMA arise from a single crustal unit. Two constrained models were arrived at through an iterative process that sought a best fit between the measured data and the NVR crustal interpretations. The first model, proposes a largely resistive unit which incorporates portions of elevated crustal conductivity; these conductors are spatially correlated to crustal portions also characterised by high seismic reflectivity. The size of this modelled body suggest the likely host of the BMA is an intermediate plutonic terrane, analogous with the Natal sector of the Namaqua Natal Mobile Belt as well as the Heimefrontfjella in Dronning Maud Land, Antarctica, with magnetite hosted within shear zones. This is in agreement with previous studies. The second model proposes a lower crustal sliver imaged in the NVR data at depths proximal to the Curie Isotherm for magnetite and hematite as the source of the BMA. At these depths geomagnetic properties such as burial magnetisation or thermo-viscous remanent magnetism (TVRM) can potentially be linked to regional scale tectonic processes and can theoretically elevate a body’s net magnetic susceptibility. TVRM has been proposed for long wavelength crustal anomalies elsewhere.
- Full Text:
- Date Issued: 2014
Electron microscopy characterisation of polycrystalline silicon carbide
- Authors: Ndzane, Nolufefe Muriel
- Date: 2014
- Subjects: Electron microscopy , Silicon carbide
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10553 , http://hdl.handle.net/10948/d1020634
- Description: This dissertation focuses on an electron microscopy investigation of the microstructure of SiC layers in TRISO coated particles deposited by chemical vapour deposition under different experimental conditions, which include temperature, concentration of gases and deposition time. The polycrystalline β-SiC was deposited from the decomposition of methyl trichlorosilane MTS in the presence of hydrogen (H2) as carrier gas. Scanning electron microscopy (SEM), using the backscattered electron (BSE) mode, was used to image the microstructure of and defects in the SiC layers of TRISO particles. Electron backscatter diffraction (EBSD) in the SEM was used to determine the SiC grain sizes and distribution thereof in TRISO particles deposited under different conditions. For samples with a poor EBSD indexing rate, transmission Kikuchi diffraction and transmission electron microscopy (TEM) investigations were also carried out. From the results, the effects of growth temperature on the SiC microstructure, specifically on the grain size and shape and the porosity were determined. The effects of cooling or non-cooling of the gas inlet nozzle on the SiC microstructure were also investigated. TEM and scanning TEM (STEM) analyses of the SiC layers in TRISO particles were performed to image the defects and reveal the crystallinity of SiC layers. The microstructure and composition of SiC tubes fabricated by reaction bonding (RB) was also investigated by using electron microscopy and Raman spectroscopy. SEM-BSE imaging of RBSiC samples allowed the identification of impurities and free silicon in the RBSiC. Finally, the penetration of the metallic fission product, palladium, in reaction bonded SiC at a temperature of a 1000ºC is determined. A brief comment on the suitability of RBSiC as candidate for fuel cladding in a PWR is made. A short discussion of the suitability of the characterisation techniques used is included at the end.
- Full Text:
- Date Issued: 2014
- Authors: Ndzane, Nolufefe Muriel
- Date: 2014
- Subjects: Electron microscopy , Silicon carbide
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10553 , http://hdl.handle.net/10948/d1020634
- Description: This dissertation focuses on an electron microscopy investigation of the microstructure of SiC layers in TRISO coated particles deposited by chemical vapour deposition under different experimental conditions, which include temperature, concentration of gases and deposition time. The polycrystalline β-SiC was deposited from the decomposition of methyl trichlorosilane MTS in the presence of hydrogen (H2) as carrier gas. Scanning electron microscopy (SEM), using the backscattered electron (BSE) mode, was used to image the microstructure of and defects in the SiC layers of TRISO particles. Electron backscatter diffraction (EBSD) in the SEM was used to determine the SiC grain sizes and distribution thereof in TRISO particles deposited under different conditions. For samples with a poor EBSD indexing rate, transmission Kikuchi diffraction and transmission electron microscopy (TEM) investigations were also carried out. From the results, the effects of growth temperature on the SiC microstructure, specifically on the grain size and shape and the porosity were determined. The effects of cooling or non-cooling of the gas inlet nozzle on the SiC microstructure were also investigated. TEM and scanning TEM (STEM) analyses of the SiC layers in TRISO particles were performed to image the defects and reveal the crystallinity of SiC layers. The microstructure and composition of SiC tubes fabricated by reaction bonding (RB) was also investigated by using electron microscopy and Raman spectroscopy. SEM-BSE imaging of RBSiC samples allowed the identification of impurities and free silicon in the RBSiC. Finally, the penetration of the metallic fission product, palladium, in reaction bonded SiC at a temperature of a 1000ºC is determined. A brief comment on the suitability of RBSiC as candidate for fuel cladding in a PWR is made. A short discussion of the suitability of the characterisation techniques used is included at the end.
- Full Text:
- Date Issued: 2014
Identification of membrane biomakers for colorectal cancer using an in-solico and molecular approach
- Authors: Van Vuuren, Larry Peter
- Date: 2014
- Subjects: Cancer -- Research , Colon (Anatomy) -- Cancer , Rectum -- Cancer
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/47970 , vital:40457
- Description: The aim of this study was to identify membrane biomarkers for colorectal cancer using an insilico and molecular approach. Colorectal cancer (CRC) globally accounts for more than half a million deaths. In South Africa alone, approximately one in 97 men is at risk of getting CRC; and for women, it is one in 162. Novel and non-invasive diagnostic tools, such as biomarkers, are needed for early CRC detection. In order to reduce the fatality rate in this disease, Biomarkers are used as indicators of a biological state; and they are measurable in biological media. They can be used to distinguish between a diseased state and a normal state, thus aiding diagnostics, response to specific therapies, and screening for an early diagnosis. A gene list of potential CRC biomarkers was generated by mining two gene databases, namely: Oncomine and Gene Expression Atlas. A total of 44 candidate genes were identified, based on their location on the cell surface, using the Database for Annotation, Visualisation and Integrated Discovery. These 44 genes were then subjected to an in-depth literature mining. The literature search parameters in PubMed, PubMed Central, Google Scholar and Science direct revealed publications showing that 23 genes were validated, while 21 genes were not validated. Nineteen genes were selected for gene validation in human colorectal cancer and healthy tissue of twelve patients. Total RNA was extracted from 12 colorectal cancer and 12 healthy tissue samples. The RNA was then quantified and reverse-transcribed into cDNA for gene expression analysis. The qPCR running conditions were optimized, by running a melting curve, in order to determine the optimum annealing temperatures. Primarily melt curves were run for nineteen of these twenty-one genes. Melt-curve analysis showed that nine genes were poor candidates for further validation studies; and therefore, only ten genes, namely: AGTRAP, ANKRD46, BACE2, CFB, CIAO1, NOMO3, PTDSS1, SLC5A6, TNFRSF12A and ZDHHC9 were validated by qPCR in human resected colorectal carcinoma and the normal tissues of twelve patients. The qPCR results showed that ZDHHC9 and the SLC5A6 genes were the only two statistically significant ones; and they were found to be down-regulated in human colorectal cancer vs healthy tissue samples.
- Full Text:
- Date Issued: 2014
Identification of membrane biomakers for colorectal cancer using an in-solico and molecular approach
- Authors: Van Vuuren, Larry Peter
- Date: 2014
- Subjects: Cancer -- Research , Colon (Anatomy) -- Cancer , Rectum -- Cancer
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/47970 , vital:40457
- Description: The aim of this study was to identify membrane biomarkers for colorectal cancer using an insilico and molecular approach. Colorectal cancer (CRC) globally accounts for more than half a million deaths. In South Africa alone, approximately one in 97 men is at risk of getting CRC; and for women, it is one in 162. Novel and non-invasive diagnostic tools, such as biomarkers, are needed for early CRC detection. In order to reduce the fatality rate in this disease, Biomarkers are used as indicators of a biological state; and they are measurable in biological media. They can be used to distinguish between a diseased state and a normal state, thus aiding diagnostics, response to specific therapies, and screening for an early diagnosis. A gene list of potential CRC biomarkers was generated by mining two gene databases, namely: Oncomine and Gene Expression Atlas. A total of 44 candidate genes were identified, based on their location on the cell surface, using the Database for Annotation, Visualisation and Integrated Discovery. These 44 genes were then subjected to an in-depth literature mining. The literature search parameters in PubMed, PubMed Central, Google Scholar and Science direct revealed publications showing that 23 genes were validated, while 21 genes were not validated. Nineteen genes were selected for gene validation in human colorectal cancer and healthy tissue of twelve patients. Total RNA was extracted from 12 colorectal cancer and 12 healthy tissue samples. The RNA was then quantified and reverse-transcribed into cDNA for gene expression analysis. The qPCR running conditions were optimized, by running a melting curve, in order to determine the optimum annealing temperatures. Primarily melt curves were run for nineteen of these twenty-one genes. Melt-curve analysis showed that nine genes were poor candidates for further validation studies; and therefore, only ten genes, namely: AGTRAP, ANKRD46, BACE2, CFB, CIAO1, NOMO3, PTDSS1, SLC5A6, TNFRSF12A and ZDHHC9 were validated by qPCR in human resected colorectal carcinoma and the normal tissues of twelve patients. The qPCR results showed that ZDHHC9 and the SLC5A6 genes were the only two statistically significant ones; and they were found to be down-regulated in human colorectal cancer vs healthy tissue samples.
- Full Text:
- Date Issued: 2014
Influence of anthropogenic stressors on the behaviour and mortality of the endangered African penguin
- Authors: Nyengera, Reason
- Date: 2014
- Subjects: African penguin -- South Africa -- Algoa Bay , Birds -- Mortality -- South Africa -- Algoa Bay , Endangered species -- Breeding -- South Africa -- Algoa Bay
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/3064 , vital:20395
- Description: This study investigated the potential impacts of several anthropogenic stressors on the movement and survival of African penguins in Algoa Bay, taking into account prey availability and environmental conditions (sea surface temperature and chlorophyll productivity). The primary drive for the study was based on the seismic exploration, which took place in the habitat of the endangered African penguin. The research was also carried out to understand how pelagic fishing and prey availability influence the broader behavioural and mortality aspects of penguins. To achieve this goal, I used monthly beach surveys to assess seabird mortality, admissions of penguins in rehabilitation centres and the monitoring of breeding penguins’ movement at sea through individual GPS tracking. In addition, prey distribution and abundance were monitored with acoustic surveys to assess potential changes in relation anthropogenic stressors. Breeding African penguins did not react dramatically to seismic activities, except on St Croix Island where they changed their foraging direction during the seismic period. There was no evidence of a siginficant increase in African penguin carcasses encountered or strandings along the beaches during the period of seismic activity. However, a sharp increase in encounter rate was recorded soon after seismic operations, which may potentially indicate a delay between the effect of seismic activities on penguin mortality and the encounter of the related carcasses after the operation. However, the impact of seismic surveys on penguins may be long-term rather than short term, and additional studies would be needed to reveal long-term effects of seismic activities, if any. Foraging effort of breeding African penguins increased substantially in the presence of commercial fishing activities within close proximity to the colonies. To a greater extent, at-sea movement patterns and counts of beach cast carcasses were largely influenced by prey availability. Penguins spent more time at sea, traveled longer and covered a larger foraging area during periods of relatvely low pelagic fish abundance. There was also a sharp increase in African penguin mortality during periods of low prey availability in the Bay. However, environmental conditions showed some influence over these interactions. Foraging effort of breeding African penguins increased substantially in the presence of commercial fishing activities within close proximity to the colonies. To a greater extent, at-sea movement patterns and counts of beach cast carcasses were largely influenced by prey availability. Penguins spent more time at sea, traveled longer and covered a larger foraging area during periods of relatvely low pelagic fish abundance. There was also a sharp increase in African penguin mortality during periods of low prey availability in the Bay. However, environmental conditions showed some influence over these interactions. For example a red tide event during in period of low prey availability, made it difficult to understand impacts of prey on penguins difficult. Both anthropogenic stressors and environmental conditions influenced African penguins’ behaviour and survival. Due to the worrying trend of African penguins in South Africa for the past few years, all conservation management efforts to increase penguin numbers and limit their mortality are necessary. This study highlights the negative impact of industrial fishing on this Endangered species and the rapid increase in mortality of penguins during times of low prey availability. A network of Marine Protected Areas would certainly increase food availability to African penguins by limiting competition with fisheries, and contribute to increasing the population numbers.
- Full Text:
- Date Issued: 2014
- Authors: Nyengera, Reason
- Date: 2014
- Subjects: African penguin -- South Africa -- Algoa Bay , Birds -- Mortality -- South Africa -- Algoa Bay , Endangered species -- Breeding -- South Africa -- Algoa Bay
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/3064 , vital:20395
- Description: This study investigated the potential impacts of several anthropogenic stressors on the movement and survival of African penguins in Algoa Bay, taking into account prey availability and environmental conditions (sea surface temperature and chlorophyll productivity). The primary drive for the study was based on the seismic exploration, which took place in the habitat of the endangered African penguin. The research was also carried out to understand how pelagic fishing and prey availability influence the broader behavioural and mortality aspects of penguins. To achieve this goal, I used monthly beach surveys to assess seabird mortality, admissions of penguins in rehabilitation centres and the monitoring of breeding penguins’ movement at sea through individual GPS tracking. In addition, prey distribution and abundance were monitored with acoustic surveys to assess potential changes in relation anthropogenic stressors. Breeding African penguins did not react dramatically to seismic activities, except on St Croix Island where they changed their foraging direction during the seismic period. There was no evidence of a siginficant increase in African penguin carcasses encountered or strandings along the beaches during the period of seismic activity. However, a sharp increase in encounter rate was recorded soon after seismic operations, which may potentially indicate a delay between the effect of seismic activities on penguin mortality and the encounter of the related carcasses after the operation. However, the impact of seismic surveys on penguins may be long-term rather than short term, and additional studies would be needed to reveal long-term effects of seismic activities, if any. Foraging effort of breeding African penguins increased substantially in the presence of commercial fishing activities within close proximity to the colonies. To a greater extent, at-sea movement patterns and counts of beach cast carcasses were largely influenced by prey availability. Penguins spent more time at sea, traveled longer and covered a larger foraging area during periods of relatvely low pelagic fish abundance. There was also a sharp increase in African penguin mortality during periods of low prey availability in the Bay. However, environmental conditions showed some influence over these interactions. Foraging effort of breeding African penguins increased substantially in the presence of commercial fishing activities within close proximity to the colonies. To a greater extent, at-sea movement patterns and counts of beach cast carcasses were largely influenced by prey availability. Penguins spent more time at sea, traveled longer and covered a larger foraging area during periods of relatvely low pelagic fish abundance. There was also a sharp increase in African penguin mortality during periods of low prey availability in the Bay. However, environmental conditions showed some influence over these interactions. For example a red tide event during in period of low prey availability, made it difficult to understand impacts of prey on penguins difficult. Both anthropogenic stressors and environmental conditions influenced African penguins’ behaviour and survival. Due to the worrying trend of African penguins in South Africa for the past few years, all conservation management efforts to increase penguin numbers and limit their mortality are necessary. This study highlights the negative impact of industrial fishing on this Endangered species and the rapid increase in mortality of penguins during times of low prey availability. A network of Marine Protected Areas would certainly increase food availability to African penguins by limiting competition with fisheries, and contribute to increasing the population numbers.
- Full Text:
- Date Issued: 2014
Lesson for spatial planning: post-1994 human settlement development in Nelson Mandela Bay Municipality
- Authors: Nagar, Manesh
- Date: 2014
- Subjects: Land settlement -- South Africa -- Port Elizabeth -- 21st century Human geography -- South Africa -- Port Elizabeth -- 21st century , City planning -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/47992 , vital:40461
- Description: Spatial planning of human settlements in South African cities, particularly during the apartheid era, has been extensively investigated. Urban development in Nelson Mandela Bay (formerly known as Port Elizabeth) resembled most other South African cities and towns based on the informants of the apartheid spatial planning policies since 1948. Consequent to the colonial style urban forms, the typical South African city and town (including Nelson Mandela Bay) faces numerous challenges to eradicate the effects of the apartheid legacies of functional and structural inefficiencies during the post-apartheid period. The research aims at examining the effectiveness of the post-apartheid residential policies with emphasis on the ‘Breaking New Ground’ policy in meeting the government’s expectations of restructuring and transformation of spatial urban planning after 1994, between 2004 and 2011 in Walmer Township. More specifically, the objectives of the study were to determine the extent of eradication of informal settlements in the study area; functional integration to investigate the extent of transformation of the study area in terms of functional integration; and to analyse the financially sustainability of the area, focused on the road network. The study was theoretically and conceptually influenced by colonial and postcolonial policies that impacted on urban development and spatial planning in the former colonial city. Methodologically, both quantitative and qualitative approaches were adopted in this investigation and in a case study. The data used for the study was obtained from both primary and secondary sources. Primary data were collected by using a remote sensing technique and via face-to-face interviews, where the interviewees were selected at random from within the identified suburb areas. Secondary data were obtained from scholarly articles and books, and government agencies and departments. The Chi-square test of dependence was used and this was to determine whether there was a relationship between variables. The results indicate that there are over 3,000 informal settlement dwellings in 2011, and very little eradication of informal settlement has been achieved. Although there are signs of heightened efforts of functional integration, it still remains limited. It was revealed that the local government has missed opportunities to promote the BNG policy objectives, particularly in the application of higher density developments and to promote cost-effective road networks. Based on the outcomes of the study, there are clear signs of the post-apartheid governments’ slow pace to transform human settlements. The post-apartheid housing policies, in particular the BNG policy, have not effectively transformed human settlements as envisaged.
- Full Text:
- Date Issued: 2014
- Authors: Nagar, Manesh
- Date: 2014
- Subjects: Land settlement -- South Africa -- Port Elizabeth -- 21st century Human geography -- South Africa -- Port Elizabeth -- 21st century , City planning -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/47992 , vital:40461
- Description: Spatial planning of human settlements in South African cities, particularly during the apartheid era, has been extensively investigated. Urban development in Nelson Mandela Bay (formerly known as Port Elizabeth) resembled most other South African cities and towns based on the informants of the apartheid spatial planning policies since 1948. Consequent to the colonial style urban forms, the typical South African city and town (including Nelson Mandela Bay) faces numerous challenges to eradicate the effects of the apartheid legacies of functional and structural inefficiencies during the post-apartheid period. The research aims at examining the effectiveness of the post-apartheid residential policies with emphasis on the ‘Breaking New Ground’ policy in meeting the government’s expectations of restructuring and transformation of spatial urban planning after 1994, between 2004 and 2011 in Walmer Township. More specifically, the objectives of the study were to determine the extent of eradication of informal settlements in the study area; functional integration to investigate the extent of transformation of the study area in terms of functional integration; and to analyse the financially sustainability of the area, focused on the road network. The study was theoretically and conceptually influenced by colonial and postcolonial policies that impacted on urban development and spatial planning in the former colonial city. Methodologically, both quantitative and qualitative approaches were adopted in this investigation and in a case study. The data used for the study was obtained from both primary and secondary sources. Primary data were collected by using a remote sensing technique and via face-to-face interviews, where the interviewees were selected at random from within the identified suburb areas. Secondary data were obtained from scholarly articles and books, and government agencies and departments. The Chi-square test of dependence was used and this was to determine whether there was a relationship between variables. The results indicate that there are over 3,000 informal settlement dwellings in 2011, and very little eradication of informal settlement has been achieved. Although there are signs of heightened efforts of functional integration, it still remains limited. It was revealed that the local government has missed opportunities to promote the BNG policy objectives, particularly in the application of higher density developments and to promote cost-effective road networks. Based on the outcomes of the study, there are clear signs of the post-apartheid governments’ slow pace to transform human settlements. The post-apartheid housing policies, in particular the BNG policy, have not effectively transformed human settlements as envisaged.
- Full Text:
- Date Issued: 2014