Fungal remediation of winery and distillery wastewaters using Trametes pubescens MB 89 and the enhanced production of a high-value enzyme therein
- Authors: Strong, Peter James
- Date: 2008
- Subjects: Fungal remediation Distilleries -- Waste disposal Wine and wine making -- Waste disposal Bioremediation Laccase Enzymes -- Biotechnology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3932 , http://hdl.handle.net/10962/d1003991
- Description: In this study white-rot fungi were investigated for their efficiency at distillery wastewater remediation and the production of laccase as a valuable by-product. Distillery wastewaters are high in organic load and low in pH. The presence of phenolic compounds can lead to extremely colour-rich wastewaters and can be toxic to microorganisms. The presence of the inorganic ions may also affect biological treatment. White-rot fungi are unique among eukaryotic or prokaryotic microbes in possessing powerful oxidative enzyme systems that can degrade lignin to carbon dioxide. These ligninolytic enzymes, such as lignin peroxidase, manganese peroxidase and laccase, are capable of degrading a vast range of toxic, recalcitrant environmental pollutants and this makes the white-rot fungi strong candidates for the bioremediation of polluted soils and waters. The laccase enzyme alone has shown remediation potential in wastewaters such as beer production effluent, olive mill wastewater, alcohol distillery wastes, dye-containing wastewaters from the textile industry as well as wastewaters from the paper and pulp industry. It has been shown to be capable of remediating soils and waters polluted with chlorinated phenolic compounds, polyaromatic hydrocarbons, nitrosubstituted compounds and fungicides, herbicides and insecticides.
- Full Text:
- Date Issued: 2008
- Authors: Strong, Peter James
- Date: 2008
- Subjects: Fungal remediation Distilleries -- Waste disposal Wine and wine making -- Waste disposal Bioremediation Laccase Enzymes -- Biotechnology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3932 , http://hdl.handle.net/10962/d1003991
- Description: In this study white-rot fungi were investigated for their efficiency at distillery wastewater remediation and the production of laccase as a valuable by-product. Distillery wastewaters are high in organic load and low in pH. The presence of phenolic compounds can lead to extremely colour-rich wastewaters and can be toxic to microorganisms. The presence of the inorganic ions may also affect biological treatment. White-rot fungi are unique among eukaryotic or prokaryotic microbes in possessing powerful oxidative enzyme systems that can degrade lignin to carbon dioxide. These ligninolytic enzymes, such as lignin peroxidase, manganese peroxidase and laccase, are capable of degrading a vast range of toxic, recalcitrant environmental pollutants and this makes the white-rot fungi strong candidates for the bioremediation of polluted soils and waters. The laccase enzyme alone has shown remediation potential in wastewaters such as beer production effluent, olive mill wastewater, alcohol distillery wastes, dye-containing wastewaters from the textile industry as well as wastewaters from the paper and pulp industry. It has been shown to be capable of remediating soils and waters polluted with chlorinated phenolic compounds, polyaromatic hydrocarbons, nitrosubstituted compounds and fungicides, herbicides and insecticides.
- Full Text:
- Date Issued: 2008
A study of a class of invariant optimal control problems on the Euclidean group SE(2)
- Authors: Adams, Ross Montague
- Date: 2011
- Subjects: Matrix groups Lie groups Extremal problems (Mathematics) Maximum principles (Mathematics) Hamilton-Jacobi equations Lyapunov stability
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5420 , http://hdl.handle.net/10962/d1006060
- Description: The aim of this thesis is to study a class of left-invariant optimal control problems on the matrix Lie group SE(2). We classify, under detached feedback equivalence, all controllable (left-invariant) control affine systems on SE(2). This result produces six types of control affine systems on SE(2). Hence, we study six associated left-invariant optimal control problems on SE(2). A left-invariant optimal control problem consists of minimizing a cost functional over the trajectory-control pairs of a left-invariant control system subject to appropriate boundary conditions. Each control problem is lifted from SE(2) to T*SE(2) ≅ SE(2) x se (2)*and then reduced to a problem on se (2)*. The maximum principle is used to obtain the optimal control and Hamiltonian corresponding to the normal extremals. Then we derive the (reduced) extremal equations on se (2)*. These equations are explicitly integrated by trigonometric and Jacobi elliptic functions. Finally, we fully classify, under Lyapunov stability, the equilibrium states of the normal extremal equations for each of the six types under consideration.
- Full Text:
- Date Issued: 2011
- Authors: Adams, Ross Montague
- Date: 2011
- Subjects: Matrix groups Lie groups Extremal problems (Mathematics) Maximum principles (Mathematics) Hamilton-Jacobi equations Lyapunov stability
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5420 , http://hdl.handle.net/10962/d1006060
- Description: The aim of this thesis is to study a class of left-invariant optimal control problems on the matrix Lie group SE(2). We classify, under detached feedback equivalence, all controllable (left-invariant) control affine systems on SE(2). This result produces six types of control affine systems on SE(2). Hence, we study six associated left-invariant optimal control problems on SE(2). A left-invariant optimal control problem consists of minimizing a cost functional over the trajectory-control pairs of a left-invariant control system subject to appropriate boundary conditions. Each control problem is lifted from SE(2) to T*SE(2) ≅ SE(2) x se (2)*and then reduced to a problem on se (2)*. The maximum principle is used to obtain the optimal control and Hamiltonian corresponding to the normal extremals. Then we derive the (reduced) extremal equations on se (2)*. These equations are explicitly integrated by trigonometric and Jacobi elliptic functions. Finally, we fully classify, under Lyapunov stability, the equilibrium states of the normal extremal equations for each of the six types under consideration.
- Full Text:
- Date Issued: 2011
The development of biological tools to aid in the genetic investigation of the black (Diceros bicornis) and white (Ceratotherium simum) rhinoceros mitochondrial genomes
- Authors: Parsons, Michelle
- Date: 2015
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/56059 , vital:26769
- Description: The black (Diceros bicornis) and white (Ceratotherium simum) rhinoceros are found in South Africa. A decline in the populations of these species has resulted due to human activities such as habitat fragmentation and poaching. This has contributed to the loss of genetic diversity amongst the black and white rhinoceros. Conservation and anti-poaching efforts are needed to help maintain genetic diversity. These efforts could be improved through the development of non-invasive techniques to examine DNA from threatened animals. The aim of this research was to develop a molecular technique which would allow for the identification of the black and white rhinoceros and to develop a molecular technique which would allow for intraspecies genetic variation to be examined. DNA extractions were performed on matched faecal and tissue samples that were collected from two regions in South Africa. Polymerase chain reaction (PCR) primer sets were designed to investigate several regions of the rhinoceros mitochondrial genome. PCR optimisation was completed for the target regions. Sequencing was conducted on all final PCR products. The cytochrome c oxidase subunit 1 (COIi) gene allowed for the rhinoceros family to be identified. This region was digested with the HindIII restriction enzyme, which allowed for the specific identification of either the black or white rhinoceros. A subsequent region of the cytochrome c oxidase subunit 1 (COIii) as well as the D-loop, hypervariable regions (HV1 and HV2), cytochrome b (cytb) and 16s rRNA regions were investigated. These regions displayed potential for establishing geographic origin for black rhinoceros samples, whereas the D-loop and HV2 show potential for the white rhinoceros. The white rhinoceros displayed sequence variation in the HV2 and cytb region, while variation was observed in the COIi and HV1 for the black rhinoceros. All investigated target regions allowed for the rhinoceros family to be identified. The COI (COIi and COIii), HV2 and cytb regions allowed for the subspecies of rhinoceros to be identified, however the D-loop was not able to identify the white rhinoceros species. The 16s rRNA and HV1 regions allowed for the correct subspecies of rhinoceros to be identified, however as the primers were only compatible for the black rhinoceros therefore a subsequent investigation is required for the white rhinoceros. The establishment of this novel PCR based technique to identify white and black rhinoceros will allow for efficient species identification in wildlife forensic cases. A biological method was established to study intraspecies variation for the white and black rhinoceros; however the investigated target regions did not yield sufficient genetic variation. The core techniques developed in this study will be valuable for future studies that wish to investigate genetic variation in mammal species.
- Full Text:
- Date Issued: 2015
- Authors: Parsons, Michelle
- Date: 2015
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/56059 , vital:26769
- Description: The black (Diceros bicornis) and white (Ceratotherium simum) rhinoceros are found in South Africa. A decline in the populations of these species has resulted due to human activities such as habitat fragmentation and poaching. This has contributed to the loss of genetic diversity amongst the black and white rhinoceros. Conservation and anti-poaching efforts are needed to help maintain genetic diversity. These efforts could be improved through the development of non-invasive techniques to examine DNA from threatened animals. The aim of this research was to develop a molecular technique which would allow for the identification of the black and white rhinoceros and to develop a molecular technique which would allow for intraspecies genetic variation to be examined. DNA extractions were performed on matched faecal and tissue samples that were collected from two regions in South Africa. Polymerase chain reaction (PCR) primer sets were designed to investigate several regions of the rhinoceros mitochondrial genome. PCR optimisation was completed for the target regions. Sequencing was conducted on all final PCR products. The cytochrome c oxidase subunit 1 (COIi) gene allowed for the rhinoceros family to be identified. This region was digested with the HindIII restriction enzyme, which allowed for the specific identification of either the black or white rhinoceros. A subsequent region of the cytochrome c oxidase subunit 1 (COIii) as well as the D-loop, hypervariable regions (HV1 and HV2), cytochrome b (cytb) and 16s rRNA regions were investigated. These regions displayed potential for establishing geographic origin for black rhinoceros samples, whereas the D-loop and HV2 show potential for the white rhinoceros. The white rhinoceros displayed sequence variation in the HV2 and cytb region, while variation was observed in the COIi and HV1 for the black rhinoceros. All investigated target regions allowed for the rhinoceros family to be identified. The COI (COIi and COIii), HV2 and cytb regions allowed for the subspecies of rhinoceros to be identified, however the D-loop was not able to identify the white rhinoceros species. The 16s rRNA and HV1 regions allowed for the correct subspecies of rhinoceros to be identified, however as the primers were only compatible for the black rhinoceros therefore a subsequent investigation is required for the white rhinoceros. The establishment of this novel PCR based technique to identify white and black rhinoceros will allow for efficient species identification in wildlife forensic cases. A biological method was established to study intraspecies variation for the white and black rhinoceros; however the investigated target regions did not yield sufficient genetic variation. The core techniques developed in this study will be valuable for future studies that wish to investigate genetic variation in mammal species.
- Full Text:
- Date Issued: 2015
Network analysis of trophic linkages in two sub-tropical estuaries along the South-East coast of South Africa
- Authors: Vosloo, Mathys Christiaan
- Date: 2012
- Subjects: Estuaries -- South Africa -- Eastern Cape , Estuarine ecology , Network analysis (Planning)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10708 , http://hdl.handle.net/10948/d1010966 , Estuaries -- South Africa -- Eastern Cape , Estuarine ecology , Network analysis (Planning)
- Description: Estuaries are some of the most productive yet threatened ecosystems in the world. Despite their importance they face significant threats through changes to river flow, eutrophication, rapid population growth long the caost and harvesting of natural resources. A number of international studies have been conducted investigating the structure and functioning of an array of ecosystems using ecological network analysis. Energy flow networks have been contsructed for coastal, lagoonal, intertidial and, most notably, permantently open estuaries. Despite the valualble insights contributed by these and other studies, a lack of information on the majority of estuarine ecosystems exists.
- Full Text:
- Date Issued: 2012
- Authors: Vosloo, Mathys Christiaan
- Date: 2012
- Subjects: Estuaries -- South Africa -- Eastern Cape , Estuarine ecology , Network analysis (Planning)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10708 , http://hdl.handle.net/10948/d1010966 , Estuaries -- South Africa -- Eastern Cape , Estuarine ecology , Network analysis (Planning)
- Description: Estuaries are some of the most productive yet threatened ecosystems in the world. Despite their importance they face significant threats through changes to river flow, eutrophication, rapid population growth long the caost and harvesting of natural resources. A number of international studies have been conducted investigating the structure and functioning of an array of ecosystems using ecological network analysis. Energy flow networks have been contsructed for coastal, lagoonal, intertidial and, most notably, permantently open estuaries. Despite the valualble insights contributed by these and other studies, a lack of information on the majority of estuarine ecosystems exists.
- Full Text:
- Date Issued: 2012
The use of Landsat ETM imagery as a suitable data capture source for alien acacia species for the WFW programme
- Authors: Cobbing, Benedict Louis
- Date: 2007
- Subjects: Geographic information systems , Global Positioning System , Landsat satellites , Agriculture -- Remote sensing , Geography -- Remote sensing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4856 , http://hdl.handle.net/10962/d1005532 , Geographic information systems , Global Positioning System , Landsat satellites , Agriculture -- Remote sensing , Geography -- Remote sensing
- Description: Geographic Information System technology today allows for the rapid analysis of vast amounts of spatial and non-spatial data. The power of a GIS can only be effected with the rapid collection of accurate input data. This is particularly true in the case of the South African National Working for Water (WFW) Programme where large volumes of spatial data on alien vegetation infestations are captured throughout the country. Alien vegetation clearing contracts cannot be generated, for WFW, without this data, so that the accurate capture of such data is crucial to the success of the programme. Mapping Invasive Alien Plant (IAP) data within WFW is a perennial problem (Coetzee, pers com, 2002), because not enough mapping is being done to meet the annual requirements of the programme in the various provinces. This is re-iterated by Richardson, 2004, who states that there is a shortage of accurate data on IAP abundance in South Africa. Therefore there is a need to investigate alternate methods of data capture; such as remote sensing, whilst working within the existing WFW data capture standards. The aim of this research was to investigate the use of Landsat ETM imagery as a data capture source for mapping alien vegetation for the WFW Programme in terms of their approved mapping methods, for both automated and manual classification techniques. The automated and manual classification results were compared to control data captured by differential Global Positioning Systems (DGPS). The research tested the various methods of data capture using Landsat ETM images over a range of study sites of varying complexity: a simple grassland area, a medium complexity grassy fynbos site and a complicated indigenous forest site. An important component of the research was to develop a mapping (classification) Ranking System based upon variables identified by WFW as fundamental in data capture decision making: spatial and positional accuracy, time constraints and cost constraints for three typical alien invaded areas. The mapping Ranking System compared the results of the various mapping methods for each factor for the study sites against each other. This provided an indication of which mapping method is the most efficient or suitable for a particular area.
- Full Text:
- Date Issued: 2007
- Authors: Cobbing, Benedict Louis
- Date: 2007
- Subjects: Geographic information systems , Global Positioning System , Landsat satellites , Agriculture -- Remote sensing , Geography -- Remote sensing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4856 , http://hdl.handle.net/10962/d1005532 , Geographic information systems , Global Positioning System , Landsat satellites , Agriculture -- Remote sensing , Geography -- Remote sensing
- Description: Geographic Information System technology today allows for the rapid analysis of vast amounts of spatial and non-spatial data. The power of a GIS can only be effected with the rapid collection of accurate input data. This is particularly true in the case of the South African National Working for Water (WFW) Programme where large volumes of spatial data on alien vegetation infestations are captured throughout the country. Alien vegetation clearing contracts cannot be generated, for WFW, without this data, so that the accurate capture of such data is crucial to the success of the programme. Mapping Invasive Alien Plant (IAP) data within WFW is a perennial problem (Coetzee, pers com, 2002), because not enough mapping is being done to meet the annual requirements of the programme in the various provinces. This is re-iterated by Richardson, 2004, who states that there is a shortage of accurate data on IAP abundance in South Africa. Therefore there is a need to investigate alternate methods of data capture; such as remote sensing, whilst working within the existing WFW data capture standards. The aim of this research was to investigate the use of Landsat ETM imagery as a data capture source for mapping alien vegetation for the WFW Programme in terms of their approved mapping methods, for both automated and manual classification techniques. The automated and manual classification results were compared to control data captured by differential Global Positioning Systems (DGPS). The research tested the various methods of data capture using Landsat ETM images over a range of study sites of varying complexity: a simple grassland area, a medium complexity grassy fynbos site and a complicated indigenous forest site. An important component of the research was to develop a mapping (classification) Ranking System based upon variables identified by WFW as fundamental in data capture decision making: spatial and positional accuracy, time constraints and cost constraints for three typical alien invaded areas. The mapping Ranking System compared the results of the various mapping methods for each factor for the study sites against each other. This provided an indication of which mapping method is the most efficient or suitable for a particular area.
- Full Text:
- Date Issued: 2007
The implementation of a core architecture for geophysical data acquisition
- Authors: Heasman, Ray Edward
- Date: 2000
- Subjects: Geophysics -- Data processing , Computer software -- Development , Seismometers , Computer input-output equipment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5471 , http://hdl.handle.net/10962/d1005256 , Geophysics -- Data processing , Computer software -- Development , Seismometers , Computer input-output equipment
- Description: This thesis describes the design, development and implementation of the core hardware and software of a modular data acquisition system for geophysical data collection. The primary application for this system is the acquisition and realtime processing of seismic data captured in mines. This system will be used by a commercial supplier of seismic instrumentation, ISS International, as a base architecture for the development of future products. The hardware and software has been designed to be extendable and support distributed processing. The IEEE-1394 High Performance Serial Bus is used to communicate with other CPU modules or peripherals. The software includes a pre-emptive multitasking microkernel, an asynchronous mailbox-based message passing communications system, and a functional IEEE-1394 protocol stack. The reasons for the end design and implementation decisions are given, and the problems encountered in the development of this system are described. A critical assessment of the match between the requirements for the project and the functionality of the implementation is made.
- Full Text:
- Date Issued: 2000
- Authors: Heasman, Ray Edward
- Date: 2000
- Subjects: Geophysics -- Data processing , Computer software -- Development , Seismometers , Computer input-output equipment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5471 , http://hdl.handle.net/10962/d1005256 , Geophysics -- Data processing , Computer software -- Development , Seismometers , Computer input-output equipment
- Description: This thesis describes the design, development and implementation of the core hardware and software of a modular data acquisition system for geophysical data collection. The primary application for this system is the acquisition and realtime processing of seismic data captured in mines. This system will be used by a commercial supplier of seismic instrumentation, ISS International, as a base architecture for the development of future products. The hardware and software has been designed to be extendable and support distributed processing. The IEEE-1394 High Performance Serial Bus is used to communicate with other CPU modules or peripherals. The software includes a pre-emptive multitasking microkernel, an asynchronous mailbox-based message passing communications system, and a functional IEEE-1394 protocol stack. The reasons for the end design and implementation decisions are given, and the problems encountered in the development of this system are described. A critical assessment of the match between the requirements for the project and the functionality of the implementation is made.
- Full Text:
- Date Issued: 2000
Studies in the plant ecology of Fern Kloof near Grahamstown
- Authors: Seagrief, S C
- Date: 1950
- Subjects: Plant communities -- South Africa -- Eastern Cape , Plant ecology -- South Africa -- Eastern Cape , Plants -- South Africa -- Eastern Cape , Forest ecology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4267 , http://hdl.handle.net/10962/d1014299
- Description: The area studied at Fern Kloof, near Grahamstown, consists of a strip of vegetation approximately 260 yds. long and 50 yds. wide, in which there are two communities: 1) indigenous forest 2) exotic Pine forest (which has only one tree species Pinus pinaster). Throughout the thesis this species is referred to as the pine. The object of the investigation has been to determine whether these communities are natural or not. This has involved a study of the floristic composition, the life forms and the structure of the plant communities. In addition, various soil and environmental factors have been studied.
- Full Text:
- Date Issued: 1950
- Authors: Seagrief, S C
- Date: 1950
- Subjects: Plant communities -- South Africa -- Eastern Cape , Plant ecology -- South Africa -- Eastern Cape , Plants -- South Africa -- Eastern Cape , Forest ecology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4267 , http://hdl.handle.net/10962/d1014299
- Description: The area studied at Fern Kloof, near Grahamstown, consists of a strip of vegetation approximately 260 yds. long and 50 yds. wide, in which there are two communities: 1) indigenous forest 2) exotic Pine forest (which has only one tree species Pinus pinaster). Throughout the thesis this species is referred to as the pine. The object of the investigation has been to determine whether these communities are natural or not. This has involved a study of the floristic composition, the life forms and the structure of the plant communities. In addition, various soil and environmental factors have been studied.
- Full Text:
- Date Issued: 1950
Where the global meets the local : South African youth and their experience of global media
- Authors: Strelitz, Larry Nathan
- Date: 2003
- Subjects: Mass media and youth -- South Africa Mass media -- Sociological aspects Mass media and culture -- South Africa Youth -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3290 , http://hdl.handle.net/10962/d1003078
- Description: Within the context of debates concerning the impact of global media on local youth, this study explores how a sample of South African youth responds to texts which were produced internationally, but distributed locally. Recognising the profound rootedness of media consumption in everyday life, the research examines the way these youth, differentially embedded in the South African economic and ideological formation, use these texts as part of their ongoing attempts to make sense of their lives. The study rejects the 'either/or' formulations that often accompany competing structuralist and culturalist approaches to text/audience relationships. Instead, using a combination of quantitative and qualitative research methods, it seeks to highlight the interplay between agency and structure, between individual choice and the structuring of experience by wider social and historical factors. The findings of the study point to the complex individual and social reasons that lie behind media consumption choices, and the diverse (and socially patterned) reasons why local audiences are either attracted to, or reject, global media. These and other findings, the study argues, highlight the deficiencies of the media imperialism thesis with its definitive claims for cultural homogenisation, seen as the primary, or most politically significant, effect of the globalisation of media. As such, this study should be read as a dialogue with those schools of thought that take a more unequivocal point of view on the impact of globalised media culture.
- Full Text:
- Date Issued: 2003
- Authors: Strelitz, Larry Nathan
- Date: 2003
- Subjects: Mass media and youth -- South Africa Mass media -- Sociological aspects Mass media and culture -- South Africa Youth -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3290 , http://hdl.handle.net/10962/d1003078
- Description: Within the context of debates concerning the impact of global media on local youth, this study explores how a sample of South African youth responds to texts which were produced internationally, but distributed locally. Recognising the profound rootedness of media consumption in everyday life, the research examines the way these youth, differentially embedded in the South African economic and ideological formation, use these texts as part of their ongoing attempts to make sense of their lives. The study rejects the 'either/or' formulations that often accompany competing structuralist and culturalist approaches to text/audience relationships. Instead, using a combination of quantitative and qualitative research methods, it seeks to highlight the interplay between agency and structure, between individual choice and the structuring of experience by wider social and historical factors. The findings of the study point to the complex individual and social reasons that lie behind media consumption choices, and the diverse (and socially patterned) reasons why local audiences are either attracted to, or reject, global media. These and other findings, the study argues, highlight the deficiencies of the media imperialism thesis with its definitive claims for cultural homogenisation, seen as the primary, or most politically significant, effect of the globalisation of media. As such, this study should be read as a dialogue with those schools of thought that take a more unequivocal point of view on the impact of globalised media culture.
- Full Text:
- Date Issued: 2003
The synthesis, empirical and theoretical studies of various (N→B) diarylborinate esters
- Authors: Manana, Pholani Sakhile
- Date: 2021-12
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/53869 , vital:46027
- Description: A series of core-functionalized borinic acids was synthesized from Grignard reagents and tributylborate and reacted with ethanolamine, amino acids, 2-pyridylmethanol as well as 2-(ethyl amino ethanol). Among the borinic acids synthesized were the ones bearing: para-(2, 15, 16, 22, 27)-methyl, (3, 20, 25)-chloro, (4, 23, 26)-fluoro, (5)-methoxy; meta-(7, 17)-methyl, (9)-fluoro; ortho-(6)-methyl, (8)-chloro, (10, 18, 19)-methoxy substituents on their respective aromatic systems. All compounds obtained by condensation of the borinic acids with the aforementioned nitrogen-containing substrates were characterized structurally by means of diffraction studies based on single crystals and found to constitute chelate esters/amides featuring covalent B-O and dative N→B bonds. The chelate compounds researched in this study could be classified into four families and represent the compounds: ethanol amine: (1) 2,2-diphenyl-1,3,2-oxazaborolidines, (2) 2,2-bis(p-tolyl)-1,3,2-oxazaborolidines, (3) 2,2-bis(p-chlorophenyl)-1,3,2-oxazaborolidines, (4) 2,2-bis(p-fluorophenyl)-1,3,2-oxazaborolidines, (5) 2,2-bis(p-methoxyphenyl)-1,3,2-oxazaborolidines, (6) 2,2-bis(o-tolyl)-1,3,2-oxazaborolidines, (7) 2,2-bis(m-tolyl)-1,3,2-oxazaborolidines, (8) 2,2-bis(o-chlorophenyl)-1,3,2-oxazaborolidines, (9) 2,2-bis(m-fluorophenyl)-1,3,2-oxazaborolidines, (10) 2,2-bis(o-methoxyphenyl)-1,3,2-oxazaborolidines. α-amino acids : (14) 4-methyl-2,2-diphenyl-1,3,2-oxazaborolidin-5-ones, (15) 2,2-bis(p-tolyl)-1,3,2-oxazaborolidin-5-ones, (16) 4-methyl-2,2-bis(p-tolyl)-1,3,2-oxazaborolidin-5-ones, (17) 4-isopropyl-2,2-bis(m-tolyl)-1,3,2-oxazaborolidin-5-ones, (18) 4-methyl-2,2-bis(o-methoxyphenyl)-1,3,2- oxazaborolidin-5-ones, (19) 4-acetamidyl-2,2-bis(o-methoxyphenyl)-1,3,2- oxazaborolidin-5-ones, (20) 4-phenylethane-2,2-bis(p-chlorophenyl)-1,3,2 oxazaborolidin-5-ones. 2-pyridylmethanol: (21) 1,3-hydroxypyridyl-2,2-diphenyl 1,3,2-oxazaborolidines, (22) 1,3-hydroxypyridyl-2,2-bis(p-tolyl)-1,3,2-oxazaborolidines, (23) 1,3-hydroxypyridyl-2,2-bis(p-fluorophenyl)-1,3,2-oxazaborolidines 2-(ethyl amino ethanol): (24) 3-ethyl-2,2-diphenyl-1,3,2-oxazaborolidines, (25) 3-ethyl-2,2-bis(p-chlorophenyl)-1,3,2-oxazaborolidines, (26) 3-ethyl-2,2-bis(p-fluorophenyl)-1,3,2-oxazaborolidines, (27) 3-ethyl-2,2-bis(p-tolyl)-1,3,2-oxazaborolidines. Apart from structural studies in the solid state, the compounds were also characterized by means of multinuclear NMR spectroscopy (1H, 11B, 13C) as well as UV/vis and FTIR. The typical 11B resonances were found in the range of (4-10 ppm). A series of characteristic metrical parameters for the compounds in the solid state as well as typical NMR shifts for the chelate target molecules was established that allowed for the determination of the coordination induced shift. The carbon atom bonded to the oxygen atom shifted upfield, while the carbon atom bonded to the nitrogen atom shifted downfield. Factors mentioned in the literature that has an influence on the hydrolytic stability on the heterocyclic borinate motif have been taken into consideration and verified for the systems researched in this study. The substitution at the nitrogen atom with one ethyl group caused the greatest increases in the N→B bond length (27) 1.714 Å, due to the increase in the nitrogen Lewis basicity, making it the least hydrolytically stable, these include compounds (24-26). Furthermore, DFT calculations were performed by employing Becke’s three parameter hybrid exchange functional with Lee–Yang–Parr functional (B3LYP) method using the Gaussian 16 program package (Rev. B01) employing the basis set 6-311++G(d,p), to corroborate and correlate the experimental findings, which gave a general R-squared value of 0.9978 for calculated vs experimental 13C chemical shifts. Thermal properties are recorded for select compounds, indicating the ΔH and the melting points. , Thesis (PhD) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2021
- Full Text:
- Date Issued: 2021-12
- Authors: Manana, Pholani Sakhile
- Date: 2021-12
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/53869 , vital:46027
- Description: A series of core-functionalized borinic acids was synthesized from Grignard reagents and tributylborate and reacted with ethanolamine, amino acids, 2-pyridylmethanol as well as 2-(ethyl amino ethanol). Among the borinic acids synthesized were the ones bearing: para-(2, 15, 16, 22, 27)-methyl, (3, 20, 25)-chloro, (4, 23, 26)-fluoro, (5)-methoxy; meta-(7, 17)-methyl, (9)-fluoro; ortho-(6)-methyl, (8)-chloro, (10, 18, 19)-methoxy substituents on their respective aromatic systems. All compounds obtained by condensation of the borinic acids with the aforementioned nitrogen-containing substrates were characterized structurally by means of diffraction studies based on single crystals and found to constitute chelate esters/amides featuring covalent B-O and dative N→B bonds. The chelate compounds researched in this study could be classified into four families and represent the compounds: ethanol amine: (1) 2,2-diphenyl-1,3,2-oxazaborolidines, (2) 2,2-bis(p-tolyl)-1,3,2-oxazaborolidines, (3) 2,2-bis(p-chlorophenyl)-1,3,2-oxazaborolidines, (4) 2,2-bis(p-fluorophenyl)-1,3,2-oxazaborolidines, (5) 2,2-bis(p-methoxyphenyl)-1,3,2-oxazaborolidines, (6) 2,2-bis(o-tolyl)-1,3,2-oxazaborolidines, (7) 2,2-bis(m-tolyl)-1,3,2-oxazaborolidines, (8) 2,2-bis(o-chlorophenyl)-1,3,2-oxazaborolidines, (9) 2,2-bis(m-fluorophenyl)-1,3,2-oxazaborolidines, (10) 2,2-bis(o-methoxyphenyl)-1,3,2-oxazaborolidines. α-amino acids : (14) 4-methyl-2,2-diphenyl-1,3,2-oxazaborolidin-5-ones, (15) 2,2-bis(p-tolyl)-1,3,2-oxazaborolidin-5-ones, (16) 4-methyl-2,2-bis(p-tolyl)-1,3,2-oxazaborolidin-5-ones, (17) 4-isopropyl-2,2-bis(m-tolyl)-1,3,2-oxazaborolidin-5-ones, (18) 4-methyl-2,2-bis(o-methoxyphenyl)-1,3,2- oxazaborolidin-5-ones, (19) 4-acetamidyl-2,2-bis(o-methoxyphenyl)-1,3,2- oxazaborolidin-5-ones, (20) 4-phenylethane-2,2-bis(p-chlorophenyl)-1,3,2 oxazaborolidin-5-ones. 2-pyridylmethanol: (21) 1,3-hydroxypyridyl-2,2-diphenyl 1,3,2-oxazaborolidines, (22) 1,3-hydroxypyridyl-2,2-bis(p-tolyl)-1,3,2-oxazaborolidines, (23) 1,3-hydroxypyridyl-2,2-bis(p-fluorophenyl)-1,3,2-oxazaborolidines 2-(ethyl amino ethanol): (24) 3-ethyl-2,2-diphenyl-1,3,2-oxazaborolidines, (25) 3-ethyl-2,2-bis(p-chlorophenyl)-1,3,2-oxazaborolidines, (26) 3-ethyl-2,2-bis(p-fluorophenyl)-1,3,2-oxazaborolidines, (27) 3-ethyl-2,2-bis(p-tolyl)-1,3,2-oxazaborolidines. Apart from structural studies in the solid state, the compounds were also characterized by means of multinuclear NMR spectroscopy (1H, 11B, 13C) as well as UV/vis and FTIR. The typical 11B resonances were found in the range of (4-10 ppm). A series of characteristic metrical parameters for the compounds in the solid state as well as typical NMR shifts for the chelate target molecules was established that allowed for the determination of the coordination induced shift. The carbon atom bonded to the oxygen atom shifted upfield, while the carbon atom bonded to the nitrogen atom shifted downfield. Factors mentioned in the literature that has an influence on the hydrolytic stability on the heterocyclic borinate motif have been taken into consideration and verified for the systems researched in this study. The substitution at the nitrogen atom with one ethyl group caused the greatest increases in the N→B bond length (27) 1.714 Å, due to the increase in the nitrogen Lewis basicity, making it the least hydrolytically stable, these include compounds (24-26). Furthermore, DFT calculations were performed by employing Becke’s three parameter hybrid exchange functional with Lee–Yang–Parr functional (B3LYP) method using the Gaussian 16 program package (Rev. B01) employing the basis set 6-311++G(d,p), to corroborate and correlate the experimental findings, which gave a general R-squared value of 0.9978 for calculated vs experimental 13C chemical shifts. Thermal properties are recorded for select compounds, indicating the ΔH and the melting points. , Thesis (PhD) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2021
- Full Text:
- Date Issued: 2021-12
Learners' perceptions of creating a collaborative hypermedia product: an exploratory case study at Mount Pleasant Primary School
- Authors: du Plessis, André
- Date: 2004
- Subjects: Computer-assisted instruction -- South Africa Computers -- Study and teaching -- South Africa Education, Elementary -- Activity programs Competency-based education -- South Africa Educational technology -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1663 , http://hdl.handle.net/10962/d1003546
- Description: The Ministry of Education (SICTE, 2002) states that the widespread introduction of computers in schools should support Curriculum 2005 and that computer technology is part and parcel of making schools the center of community life. The vision is to establish Smart Schools: schools that are reinvented in terms of teaching-learning practices to prepare learners for the information era (SICTE, 2002). Kafai (1996:71) has found that conventional school assignments rarely give learners the opportunity to spend a great deal of time on complex projects. As a result, many learners have little experience in design: planning, problem solving, researching, dealing with time constraints, modifying expectations and synthesizing everything in a project. Research by Carver, Lehrer, Connell and Erickson (1992); Lehrer, (1993); Lehrer, Erickson and Connell (1994); Kafai (1996); Liu and Hsiao (2002) and Liu (2002) indicates that the design of hypermedia artefacts can assist in providing experience in design. To date, no equivalent research has been conducted in South Africa to ascertain the perceptions of learners regarding the creation of a hypermedia artefact over an extended period of time and whether some of the critical outcomes specified in Curriculum 2005 can be addressed in such a learning-by-design hypermedia project. This study shows that design skills and aspects related to the critical outcomes of Curriculum 2005 can be achieved. Furthermore, it indicates that this kind of project encourages interest, motivation and collaboration. In addition, it suggests that learners experience the role of the teacher as different and prefer such a learning environment. In spite of the positive results, some aspects that need attention for future implementation are suggested.
- Full Text:
- Date Issued: 2004
- Authors: du Plessis, André
- Date: 2004
- Subjects: Computer-assisted instruction -- South Africa Computers -- Study and teaching -- South Africa Education, Elementary -- Activity programs Competency-based education -- South Africa Educational technology -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1663 , http://hdl.handle.net/10962/d1003546
- Description: The Ministry of Education (SICTE, 2002) states that the widespread introduction of computers in schools should support Curriculum 2005 and that computer technology is part and parcel of making schools the center of community life. The vision is to establish Smart Schools: schools that are reinvented in terms of teaching-learning practices to prepare learners for the information era (SICTE, 2002). Kafai (1996:71) has found that conventional school assignments rarely give learners the opportunity to spend a great deal of time on complex projects. As a result, many learners have little experience in design: planning, problem solving, researching, dealing with time constraints, modifying expectations and synthesizing everything in a project. Research by Carver, Lehrer, Connell and Erickson (1992); Lehrer, (1993); Lehrer, Erickson and Connell (1994); Kafai (1996); Liu and Hsiao (2002) and Liu (2002) indicates that the design of hypermedia artefacts can assist in providing experience in design. To date, no equivalent research has been conducted in South Africa to ascertain the perceptions of learners regarding the creation of a hypermedia artefact over an extended period of time and whether some of the critical outcomes specified in Curriculum 2005 can be addressed in such a learning-by-design hypermedia project. This study shows that design skills and aspects related to the critical outcomes of Curriculum 2005 can be achieved. Furthermore, it indicates that this kind of project encourages interest, motivation and collaboration. In addition, it suggests that learners experience the role of the teacher as different and prefer such a learning environment. In spite of the positive results, some aspects that need attention for future implementation are suggested.
- Full Text:
- Date Issued: 2004
The missionary work of the first Anglican Bishop of Natal, the Rt. Reverend John William Colenso, between the years 1852-1873
- Authors: Burnett, B B
- Date: 1947
- Subjects: Colenso, John William, 1814-1883
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2621 , http://hdl.handle.net/10962/d1014679
- Description: At the outset it had been my intention to make only the slightest of references to the Church Controversy in which Bishop Colenso was involved and to have touched only lightly on his theological position. Apart from anything else I hesitated to enter the arena in which so many had already collided violently and where my own prejudices might be enlisted on one side or the other. It became evident however that Colenso the Controversialist, the Theologian could not be dissociated from Colenso the missionary, without giving an inadequate, and even misleading history of his missionary activities. The Controversy had a serious and deleterious effect on his missionary work, and no estimate of the value of a missionary's labours would be valid without some consideration of his teaching, more especially when his orthodoxy is suspect. I have therefore dealt as briefly as I could with these questions in Chapter V because of their relevance, and because to produce a work on an ecclesiastic without some reference to his tenets would be like writing a biography of Louis Botha without any allusion to his political 'faith', or of Wellington, without any mention of Waterloo. it would represent a distortion of history to write about a Missionary Bishop as though he were an amateur politician, or of a missionary as though he were interested only in finance and administration.
- Full Text:
- Date Issued: 1947
- Authors: Burnett, B B
- Date: 1947
- Subjects: Colenso, John William, 1814-1883
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2621 , http://hdl.handle.net/10962/d1014679
- Description: At the outset it had been my intention to make only the slightest of references to the Church Controversy in which Bishop Colenso was involved and to have touched only lightly on his theological position. Apart from anything else I hesitated to enter the arena in which so many had already collided violently and where my own prejudices might be enlisted on one side or the other. It became evident however that Colenso the Controversialist, the Theologian could not be dissociated from Colenso the missionary, without giving an inadequate, and even misleading history of his missionary activities. The Controversy had a serious and deleterious effect on his missionary work, and no estimate of the value of a missionary's labours would be valid without some consideration of his teaching, more especially when his orthodoxy is suspect. I have therefore dealt as briefly as I could with these questions in Chapter V because of their relevance, and because to produce a work on an ecclesiastic without some reference to his tenets would be like writing a biography of Louis Botha without any allusion to his political 'faith', or of Wellington, without any mention of Waterloo. it would represent a distortion of history to write about a Missionary Bishop as though he were an amateur politician, or of a missionary as though he were interested only in finance and administration.
- Full Text:
- Date Issued: 1947
Novel camphor derivatives as potential asymmetric alkylation auxiliaries
- Authors: Skiti-Mama, Neliswa
- Date: 2008
- Subjects: Alkylation , Chemistry, Organic
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10372 , http://hdl.handle.net/10948/1077 , Alkylation , Chemistry, Organic
- Description: The investigation has been focussed on the synthesis and characterisation of camphor-derived chiral auxiliaries that incorporate two camphor skeletons and an evaluation of their stereodirecting potential in ester α-benzylation reactions. Two regioisomeric camphorquinone-derived monoketals were synthesised and identified by 1D- and 2D-NMR, and X-ray crystallography. The stereo-directing potential of the alcohols that resulted from reduction of these ketones as chiral auxiliaries in the alkylation of carboxylate ester derivatives has been studied. The diastereoselectivities shown by NMR spectroscopy range from 14- 30 % d.e. for (1R,2 S, 3R) -2 ,2-[ (1R, 2 S, 3R) -bornane-2,3-dioxy] - bornan-3-ol and 68-74 % d.e. for (1R, 2S ,3R) -3 ,3-[ (1R, 2S ,3R) - bornane-2, 3 -dioxy]bornan-2-ol with selectivities that correlate with the size of the alkyl group in the ester moiety. Trapping of the enolates generated from (1R, 2S ,3R)-2, 2 -[(1R,2 S, 3R) -bornane- 2,3-dioxy]bornan-3-yl propanoate afforded both E- and Z-silyl ketene acetal derivatives in the ratio of 64:36 confirming the formation of both possible enolate structures during enolization. Chiral auxiliaries containing a hemiaminal ether blocking group as well as two chiral alcohols containing monothio-ketal blocking groups have also been synthesised. α-Benzylation of their corresponding propanoate esters afforded the alkylated product with disappointingly low diastereos electivities. Asymmetric reduction of α-keto esters attached to (1R, 2 S, 3R) - 2,2- [ (1R,2 S, 3R) -bornane-2, 3 -dioxy]bornan-3-ol and (1R, 2S ,3R) - 3,3- [ (1R,2 S, 3R) -bornane-2, 3 -dioxy]bornan-2-ol with metal hydrides proceeded with selectivities of up to 30 % d.e. Modelling of the keto ester derivatives at DFT levels provided useful insights into possible conformations adopted by the two α-keto esters and hence the preferred face of attack by metal hydride during reduction.
- Full Text:
- Date Issued: 2008
- Authors: Skiti-Mama, Neliswa
- Date: 2008
- Subjects: Alkylation , Chemistry, Organic
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10372 , http://hdl.handle.net/10948/1077 , Alkylation , Chemistry, Organic
- Description: The investigation has been focussed on the synthesis and characterisation of camphor-derived chiral auxiliaries that incorporate two camphor skeletons and an evaluation of their stereodirecting potential in ester α-benzylation reactions. Two regioisomeric camphorquinone-derived monoketals were synthesised and identified by 1D- and 2D-NMR, and X-ray crystallography. The stereo-directing potential of the alcohols that resulted from reduction of these ketones as chiral auxiliaries in the alkylation of carboxylate ester derivatives has been studied. The diastereoselectivities shown by NMR spectroscopy range from 14- 30 % d.e. for (1R,2 S, 3R) -2 ,2-[ (1R, 2 S, 3R) -bornane-2,3-dioxy] - bornan-3-ol and 68-74 % d.e. for (1R, 2S ,3R) -3 ,3-[ (1R, 2S ,3R) - bornane-2, 3 -dioxy]bornan-2-ol with selectivities that correlate with the size of the alkyl group in the ester moiety. Trapping of the enolates generated from (1R, 2S ,3R)-2, 2 -[(1R,2 S, 3R) -bornane- 2,3-dioxy]bornan-3-yl propanoate afforded both E- and Z-silyl ketene acetal derivatives in the ratio of 64:36 confirming the formation of both possible enolate structures during enolization. Chiral auxiliaries containing a hemiaminal ether blocking group as well as two chiral alcohols containing monothio-ketal blocking groups have also been synthesised. α-Benzylation of their corresponding propanoate esters afforded the alkylated product with disappointingly low diastereos electivities. Asymmetric reduction of α-keto esters attached to (1R, 2 S, 3R) - 2,2- [ (1R,2 S, 3R) -bornane-2, 3 -dioxy]bornan-3-ol and (1R, 2S ,3R) - 3,3- [ (1R,2 S, 3R) -bornane-2, 3 -dioxy]bornan-2-ol with metal hydrides proceeded with selectivities of up to 30 % d.e. Modelling of the keto ester derivatives at DFT levels provided useful insights into possible conformations adopted by the two α-keto esters and hence the preferred face of attack by metal hydride during reduction.
- Full Text:
- Date Issued: 2008
Economic dualism and labour re-allocation in South Africa, 1917-1970
- Authors: Hindson, Douglas Carlisle
- Date: 1975
- Subjects: Labor policy -- South Africa -- History -- 20th century , Labor laws and legislation -- South Africa , Labor economics -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:1090 , http://hdl.handle.net/10962/d1012294 , Labor policy -- South Africa -- History -- 20th century , Labor laws and legislation -- South Africa , Labor economics -- South Africa
- Description: The central concern of this study is to analyse how the pattern of development in South Africa has influenced the long term growth of productive employment in the economy. The approach adopted is to appply a model of economic dualism to the South African case. Chapter 1, p. 1.
- Full Text:
- Date Issued: 1975
- Authors: Hindson, Douglas Carlisle
- Date: 1975
- Subjects: Labor policy -- South Africa -- History -- 20th century , Labor laws and legislation -- South Africa , Labor economics -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:1090 , http://hdl.handle.net/10962/d1012294 , Labor policy -- South Africa -- History -- 20th century , Labor laws and legislation -- South Africa , Labor economics -- South Africa
- Description: The central concern of this study is to analyse how the pattern of development in South Africa has influenced the long term growth of productive employment in the economy. The approach adopted is to appply a model of economic dualism to the South African case. Chapter 1, p. 1.
- Full Text:
- Date Issued: 1975
The ibali of Nongqawuse: translating the oral tradition into visual expression
- Authors: Nhlangwini, Andrew Pandheni
- Date: 2003
- Subjects: Nongqawuse, 1841-1898 , Xhosa (African people) -- History , Oral tradition -- South Africa -- Eastern Cape , Oral history -- South Africa -- Eastern Cape , Art -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MTech (Fine Art)
- Identifier: vital:10761 , http://hdl.handle.net/10948/237 , Nongqawuse, 1841-1898 , Xhosa (African people) -- History , Oral tradition -- South Africa -- Eastern Cape , Oral history -- South Africa -- Eastern Cape , Art -- South Africa -- Eastern Cape
- Description: The tribal life and the oral traditions of black South Africans have been marginalized. The consequence of the western civilization and the apartheid regime forced people to do away from their traditional heritage and culture; they adopted the western way of life. They buried their oral tradition and only a little has survived. To save the dying culture of the art of the oral tradition we need to go out and record and document the surviving oral tradition as soon as possible. Since the art of the oral tradition is an art form conducted by an artist, it may be possible to tell the ibali likaNongqawuse by means of visual imagery. Visual images can be read and be understood easily by the public because visual forms, sings, images can make up a language for both the literate as well as the illiterate.
- Full Text:
- Date Issued: 2003
- Authors: Nhlangwini, Andrew Pandheni
- Date: 2003
- Subjects: Nongqawuse, 1841-1898 , Xhosa (African people) -- History , Oral tradition -- South Africa -- Eastern Cape , Oral history -- South Africa -- Eastern Cape , Art -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MTech (Fine Art)
- Identifier: vital:10761 , http://hdl.handle.net/10948/237 , Nongqawuse, 1841-1898 , Xhosa (African people) -- History , Oral tradition -- South Africa -- Eastern Cape , Oral history -- South Africa -- Eastern Cape , Art -- South Africa -- Eastern Cape
- Description: The tribal life and the oral traditions of black South Africans have been marginalized. The consequence of the western civilization and the apartheid regime forced people to do away from their traditional heritage and culture; they adopted the western way of life. They buried their oral tradition and only a little has survived. To save the dying culture of the art of the oral tradition we need to go out and record and document the surviving oral tradition as soon as possible. Since the art of the oral tradition is an art form conducted by an artist, it may be possible to tell the ibali likaNongqawuse by means of visual imagery. Visual images can be read and be understood easily by the public because visual forms, sings, images can make up a language for both the literate as well as the illiterate.
- Full Text:
- Date Issued: 2003
Screening of technologies for the recovery of rhodium (III) metal ions from a precious metal refinery wastewater
- Authors: Mack, Cherie-Lynn
- Date: 2005
- Subjects: Rhodium , Metal ions , Sewage -- Purification -- Metals removal , Platinum group
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3987 , http://hdl.handle.net/10962/d1004046 , Rhodium , Metal ions , Sewage -- Purification -- Metals removal , Platinum group
- Description: The selective recovery of rhodium from wastewaters, in which the metal would be otherwise lost, would be highly profitable if the process were suitably low-cost. Current recovery processes are generally high maintenance and high-cost, whereas biological processes can be engineered to run with little external input in terms of cost and maintenance. Three emerging technologies were chosen based on their reported efficiency when removing base metals from wastewaters. The first technology screened, the sulphide-extraction membrane bioreactor (SEMB), consists of a sulphate-reducing prokaryote (SRP) anaerobic digester, in which a silicone membrane is submerged. Wastewater is passed through the membrane and metal ions are precipitated as metal sulphides by the hydrogen sulphide gas, which is capable of permeating the membrane. The second technology screened was a fluidized sand bed reactor in which metal ions are removed from solution via induction of nucleated precipitation by sodium carbonate onto the sand grains. The third, and most well established removal technology screened was a biosorption system using immobilized Saccharomyces cerevisiae biomass as the biosorbent. Experimental trials with each technology highlighted drawbacks with each; the SEMB system proved to be largely ineffective when challenged with the removal of rhodium from the wastewater as the rhodium precipitate fouled the membrane within hours, the fluidized bed system seemed unable to overcome the acidity of the wastewater and thus could not precipitate out the rhodium metal, and the efficiency of the biosorption process was hampered by the diversity of rhodium species present in the wastewater, which reduced the amount recovered. The outcomes of the trials with each technology indicated that further optimization of the technology or pretreatment of the wastewater is necessary before any of these options can be implemented. It could be concluded, however, that despite further optimization, both the SEMB and the fluidized bed system were not applicable in this case as precipitation would be non-specific, resulting in the necessity for further steps in order to purify the rhodium ions. Hence, the biosorption system was shown to be most applicable, and further optimization of the system could yield a highly efficient rhodium recovery process.
- Full Text:
- Date Issued: 2005
- Authors: Mack, Cherie-Lynn
- Date: 2005
- Subjects: Rhodium , Metal ions , Sewage -- Purification -- Metals removal , Platinum group
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3987 , http://hdl.handle.net/10962/d1004046 , Rhodium , Metal ions , Sewage -- Purification -- Metals removal , Platinum group
- Description: The selective recovery of rhodium from wastewaters, in which the metal would be otherwise lost, would be highly profitable if the process were suitably low-cost. Current recovery processes are generally high maintenance and high-cost, whereas biological processes can be engineered to run with little external input in terms of cost and maintenance. Three emerging technologies were chosen based on their reported efficiency when removing base metals from wastewaters. The first technology screened, the sulphide-extraction membrane bioreactor (SEMB), consists of a sulphate-reducing prokaryote (SRP) anaerobic digester, in which a silicone membrane is submerged. Wastewater is passed through the membrane and metal ions are precipitated as metal sulphides by the hydrogen sulphide gas, which is capable of permeating the membrane. The second technology screened was a fluidized sand bed reactor in which metal ions are removed from solution via induction of nucleated precipitation by sodium carbonate onto the sand grains. The third, and most well established removal technology screened was a biosorption system using immobilized Saccharomyces cerevisiae biomass as the biosorbent. Experimental trials with each technology highlighted drawbacks with each; the SEMB system proved to be largely ineffective when challenged with the removal of rhodium from the wastewater as the rhodium precipitate fouled the membrane within hours, the fluidized bed system seemed unable to overcome the acidity of the wastewater and thus could not precipitate out the rhodium metal, and the efficiency of the biosorption process was hampered by the diversity of rhodium species present in the wastewater, which reduced the amount recovered. The outcomes of the trials with each technology indicated that further optimization of the technology or pretreatment of the wastewater is necessary before any of these options can be implemented. It could be concluded, however, that despite further optimization, both the SEMB and the fluidized bed system were not applicable in this case as precipitation would be non-specific, resulting in the necessity for further steps in order to purify the rhodium ions. Hence, the biosorption system was shown to be most applicable, and further optimization of the system could yield a highly efficient rhodium recovery process.
- Full Text:
- Date Issued: 2005
Networking: enabling professional development and institutionalisation of environmental education courses in Southern Africa
- Authors: Lupele, Justin Kalaba
- Date: 2007
- Subjects: SADC Regional Environmental Education Programme Education -- Africa, Southern Environmental education -- Africa, Southern Environmental education -- Study and teaching -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1678 , http://hdl.handle.net/10962/d1003561
- Description: This study was aimed at understanding how networking can enable or constrain professional development and institutionalisation of environmental education courses in southern Africa in the context of the Course Development Network (CDN), a project of the Southern Africa Development Community Regional Environmental Education Programme (SADC REEP). The study involved 12 institutions (each institution was represented in the CDN by a staff member) in eight SADC member states. It was contextualized through a review of social, political, environmental and educational developments in southern Africa, with specific reference to regionalization processes, as the SADC REEF is constituted under this post-colonial political framework. Relational philosophy informed the research process and methodology. The philosophy underpinned three distinct, yet related theoretical perspectives namely: critical realism, which provided the ontological perspectives of the study; Actor Network Theory; and Community of Practice, which provided the epistemological perspectives. Data was generated during a 33-month period in southern Africa and 12 months in the United Kingdom (and on a one week visit to Italy). During a 12 month Split Site Commonwealth Scholarship award, tenable at Manchester Metropolitan University in the United Kingdom, I studied the Environment and School Initiative (ENSI) and the Sustainability Education for European Primary Schools (SEEPS), to examine whether the same mechanisms that made them successful would apply to the CDN in the context of southern Africa. While these two case studies provided useful insight into the relationship between networking, professional development and institutionalization of environmental education programmes, they were not the main focus of the research. Data analysis was mainly through inductive, abductive and retroductive modes of inference. Inductive data analysis was done by means of Nvivo – a computer software package used for qualitative data analysis. The software aided in revealing features and relationships in the data in more depth as it allowed flexibility in working with data. Abduction is the interpretation of a phenomenon by means of a conceptual framework. In this study, I used Actor Network Theory (ANT) (Latour & Woolgar, 1979; Callon, 1986) and Community of Practice (COP) (Lave, 1988; Lave & Wenger, 1991; Fullan, 2003) as analytical conceptual frameworks to probe networking and professional development respectively. Data on institutionalisation of environmental education courses was analysed by means of retroductive mode of inference, which is a thought operation that enables the understanding of social reality beyond what is empirically observable or experienced. This study reveals that there were a number of necessary (internal) and contingent (external) factors that enabled or constrained networking, professional development and institutionalisation of environmental education courses in the context of the CDN. The key factors included existing cultural capital, donor political economy, power relations, poverty related factors and social transformation trends. The study found that relational approaches and the use of three relational theoretical lenses provided a broader lens which enabled this study to identify different dynamics, greater ontological depth and understanding of the relational dynamics and relations at play in the CDN beyond the participants' experience and observable events. The study also contends that networking can provide a support structure for social transformation and change in environmental education.
- Full Text:
- Date Issued: 2007
- Authors: Lupele, Justin Kalaba
- Date: 2007
- Subjects: SADC Regional Environmental Education Programme Education -- Africa, Southern Environmental education -- Africa, Southern Environmental education -- Study and teaching -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1678 , http://hdl.handle.net/10962/d1003561
- Description: This study was aimed at understanding how networking can enable or constrain professional development and institutionalisation of environmental education courses in southern Africa in the context of the Course Development Network (CDN), a project of the Southern Africa Development Community Regional Environmental Education Programme (SADC REEP). The study involved 12 institutions (each institution was represented in the CDN by a staff member) in eight SADC member states. It was contextualized through a review of social, political, environmental and educational developments in southern Africa, with specific reference to regionalization processes, as the SADC REEF is constituted under this post-colonial political framework. Relational philosophy informed the research process and methodology. The philosophy underpinned three distinct, yet related theoretical perspectives namely: critical realism, which provided the ontological perspectives of the study; Actor Network Theory; and Community of Practice, which provided the epistemological perspectives. Data was generated during a 33-month period in southern Africa and 12 months in the United Kingdom (and on a one week visit to Italy). During a 12 month Split Site Commonwealth Scholarship award, tenable at Manchester Metropolitan University in the United Kingdom, I studied the Environment and School Initiative (ENSI) and the Sustainability Education for European Primary Schools (SEEPS), to examine whether the same mechanisms that made them successful would apply to the CDN in the context of southern Africa. While these two case studies provided useful insight into the relationship between networking, professional development and institutionalization of environmental education programmes, they were not the main focus of the research. Data analysis was mainly through inductive, abductive and retroductive modes of inference. Inductive data analysis was done by means of Nvivo – a computer software package used for qualitative data analysis. The software aided in revealing features and relationships in the data in more depth as it allowed flexibility in working with data. Abduction is the interpretation of a phenomenon by means of a conceptual framework. In this study, I used Actor Network Theory (ANT) (Latour & Woolgar, 1979; Callon, 1986) and Community of Practice (COP) (Lave, 1988; Lave & Wenger, 1991; Fullan, 2003) as analytical conceptual frameworks to probe networking and professional development respectively. Data on institutionalisation of environmental education courses was analysed by means of retroductive mode of inference, which is a thought operation that enables the understanding of social reality beyond what is empirically observable or experienced. This study reveals that there were a number of necessary (internal) and contingent (external) factors that enabled or constrained networking, professional development and institutionalisation of environmental education courses in the context of the CDN. The key factors included existing cultural capital, donor political economy, power relations, poverty related factors and social transformation trends. The study found that relational approaches and the use of three relational theoretical lenses provided a broader lens which enabled this study to identify different dynamics, greater ontological depth and understanding of the relational dynamics and relations at play in the CDN beyond the participants' experience and observable events. The study also contends that networking can provide a support structure for social transformation and change in environmental education.
- Full Text:
- Date Issued: 2007
Vergelyking van Tilapia (Oreochromis Mossambicus)en Koi (Ciprinus Carpio) in verskillende produksiestelsels
- Authors: Van der Merwe, Johan Philip
- Date: 2002
- Subjects: Fish culture
- Language: Afrikaans
- Type: Thesis , Masters , MTech (Agricultural Management)
- Identifier: vital:10967 , http://hdl.handle.net/10948/114 , Fish culture
- Description: Die studie was uitgevoer om te bepaal of warmwaterspesies soos tilapia (Oreochromis mossambicus) en koi (Ciprinus carpio) gebruik kan word as deel van 'n roterende akwakultuur produksie sisteem in die Wes-Kaap. Drie produksiestelsels (drywende hokstelsel; gronddamme en hersirkuleringseenheid) was ge-evalueer vir beide tilapia en koi produksie. Twee verskillende diëte (tilapia, 32% proteien, 'n lae waarde dieet en koi, 32% proteien, 'n hoë waarde dieet) was ook ge-evalueer vir die effek op koi produksie. Tilapia- en koi vingerlinge was teen dieselfde lading (250/hok) in elke produksiestelsel geplaas. By die begin van die proewe het die tilapia vingerlinge 'n gemiddelde gewig van 60-80g en die koi vingerlinge 'n gemiddelde lengte van 30-40 mm gehad. Die visse is twee keer per dag gevoer en data is op 'n maandelikse basis oor 'n periode van 84 dae versamel. Produksie data vir die tilapia versamel was: 1) die gemiddelde daaglikse toename, 2) die totale voer verbruik, 3) water temperature en 4) mortaliteite is daagliks aangeteken. Die produksie data versamel vir koi wat twee verskillende diëte ontvang het in drie verskillende produksiestelsels was: 1) die gemiddelde daaglikse toename in lengte, 2) die totale voer verbruik, 3) water temperature en 4) mortaliteite is daagliks aangeteken. Die resultate van die tilapia studie het aangedui dat tilapia in die hersirkuleeringseenheid het deurgaans 'n swaarder gewig gehad (p<0.05) as die van die drywende hokstelsel en gronddam stelsel. Terwyl die gronddam stelsel weer 'n swaarder gewig gehad het as die drywende hokstelsel behalwe vir April (171,67 / 39,49 vs 159,33 / 22,15). Nieteenstaande die verskil in begin gewig en eind gewig in die guns van die tilapia in die hersirkuleringseenheid teenoor die ander twee stelsels het die GDT tussen die drywende hokstelsel en die hersirkuleringseenheid nie noemenswaardig verskil nie (1,20 / 0,15 vs 1,40 / 0,24). Die tilapia in die gronddamme het egter swakker (p<0,05) gewigstoename van 0,72 / 0,32 g gehad teenoor die tilapia in die drywende hokstesel 1,40 / 0,24 g en 1,20 / 0,15 g van die tilapia in die hersirkuleringseenheid. Tilapia in die gronddamme het dus ongeveer 45% swakker gemiddelde gewigstoename getoon as die van die drywende hokstelsel en hersirkuleringseenheid. Die produksiestelsel het 'n hoogs betekenisvolle invloed (p<0,001) op die groeipotensiaal van tilapia gehad in hierdie studie. Die gemiddelde totale hoeveelheid voer verbruik was nie statisties verskillend tussen die drywende hokstelsel en gronddam stelsel nie (29,83 / 2,66 vs 30,83 / 5,42), maar wel (p<0,05) vir die hersirkuleringseenheid (29,94 / 0,88). Die VOV het nie verskil tussen die drywende hokstelsel en hersirkuleringeenheid, maar daar was wel 'n verskil (p<0,05) tussen hierdie twee stelsels en die van die gronddamme. Die totale gemiddelde mortaliteite van tilapia was die hoogste (p<0,05) vir die drywende hokstelsel in vergelyking met die gronddamme en hersirkuleringseenheid. Die drywende hokstelsel het 14,67 / 14,61% meer mortaliteite gehad as die gronddamme en hersirkuleringeenheid. Die koi studie se resultate dui aan dat die tipe stelsel het 'n hoogs betekenisvolle (p<0,001) invloed gehad op die gemiddelde toename in lengte van die koi vis vir die somerseisoen. Die tipe dieet het geen invloed op die toename in lengte van koi vis vir al drie die stelsels ge-evalueer, maar die interaksie tussen dieet en die tipe stelsel was wel betekenisvol (p<0.05). Die interaksie tussen die tipe dieet en die tipe stelsel was die hoogste vir die groddamme 136,41 / 32,46 mm en 136,25 / 33,08 mm vir beide tilapia en die koi diëte gevoer. Die gemiddelde totale voer wat deur koi visse in die drie stelsels verbruik is, het wel statisties van mekaar verskil (p<0,05). Koi visse in die gronddam stelsel het meer voer verbruik vir beide die tilapia- en koi dieet (31,03 / 2,01 en 29,67 / 3,57) in vergelyking met die (26,35 / 2,44 ; 26,98 / 0,49 en 5,50 # 0,52 en 6,13 / 0,22) vir die drywende hokke en hersirkuleringseenheid stelsels onderskiedelik. Die % mortaliteite was betekenisvol (p<0,05) vir die verskillende stelsels. Koi visse in die hersirkuleringseenheid het die hoogste mortaliteite gehad vir beide die tilapia en die koi diëte (65,50 / 18,07% en 79,50 / 38,27%) terwyl koi visse in die gronddamme die laagste mortaliteite ondervind het (1,20 / 1,20% en 2,33 / 4,89%) vir beide die tilapia en koi diëte. Die koi in die gronddam stelsel het die beste resultate gelewer en dit is ook moontlik om koi 'n lae waarde dieet te voer sonder nadelige effekte op produksie.
- Full Text:
- Date Issued: 2002
- Authors: Van der Merwe, Johan Philip
- Date: 2002
- Subjects: Fish culture
- Language: Afrikaans
- Type: Thesis , Masters , MTech (Agricultural Management)
- Identifier: vital:10967 , http://hdl.handle.net/10948/114 , Fish culture
- Description: Die studie was uitgevoer om te bepaal of warmwaterspesies soos tilapia (Oreochromis mossambicus) en koi (Ciprinus carpio) gebruik kan word as deel van 'n roterende akwakultuur produksie sisteem in die Wes-Kaap. Drie produksiestelsels (drywende hokstelsel; gronddamme en hersirkuleringseenheid) was ge-evalueer vir beide tilapia en koi produksie. Twee verskillende diëte (tilapia, 32% proteien, 'n lae waarde dieet en koi, 32% proteien, 'n hoë waarde dieet) was ook ge-evalueer vir die effek op koi produksie. Tilapia- en koi vingerlinge was teen dieselfde lading (250/hok) in elke produksiestelsel geplaas. By die begin van die proewe het die tilapia vingerlinge 'n gemiddelde gewig van 60-80g en die koi vingerlinge 'n gemiddelde lengte van 30-40 mm gehad. Die visse is twee keer per dag gevoer en data is op 'n maandelikse basis oor 'n periode van 84 dae versamel. Produksie data vir die tilapia versamel was: 1) die gemiddelde daaglikse toename, 2) die totale voer verbruik, 3) water temperature en 4) mortaliteite is daagliks aangeteken. Die produksie data versamel vir koi wat twee verskillende diëte ontvang het in drie verskillende produksiestelsels was: 1) die gemiddelde daaglikse toename in lengte, 2) die totale voer verbruik, 3) water temperature en 4) mortaliteite is daagliks aangeteken. Die resultate van die tilapia studie het aangedui dat tilapia in die hersirkuleeringseenheid het deurgaans 'n swaarder gewig gehad (p<0.05) as die van die drywende hokstelsel en gronddam stelsel. Terwyl die gronddam stelsel weer 'n swaarder gewig gehad het as die drywende hokstelsel behalwe vir April (171,67 / 39,49 vs 159,33 / 22,15). Nieteenstaande die verskil in begin gewig en eind gewig in die guns van die tilapia in die hersirkuleringseenheid teenoor die ander twee stelsels het die GDT tussen die drywende hokstelsel en die hersirkuleringseenheid nie noemenswaardig verskil nie (1,20 / 0,15 vs 1,40 / 0,24). Die tilapia in die gronddamme het egter swakker (p<0,05) gewigstoename van 0,72 / 0,32 g gehad teenoor die tilapia in die drywende hokstesel 1,40 / 0,24 g en 1,20 / 0,15 g van die tilapia in die hersirkuleringseenheid. Tilapia in die gronddamme het dus ongeveer 45% swakker gemiddelde gewigstoename getoon as die van die drywende hokstelsel en hersirkuleringseenheid. Die produksiestelsel het 'n hoogs betekenisvolle invloed (p<0,001) op die groeipotensiaal van tilapia gehad in hierdie studie. Die gemiddelde totale hoeveelheid voer verbruik was nie statisties verskillend tussen die drywende hokstelsel en gronddam stelsel nie (29,83 / 2,66 vs 30,83 / 5,42), maar wel (p<0,05) vir die hersirkuleringseenheid (29,94 / 0,88). Die VOV het nie verskil tussen die drywende hokstelsel en hersirkuleringeenheid, maar daar was wel 'n verskil (p<0,05) tussen hierdie twee stelsels en die van die gronddamme. Die totale gemiddelde mortaliteite van tilapia was die hoogste (p<0,05) vir die drywende hokstelsel in vergelyking met die gronddamme en hersirkuleringseenheid. Die drywende hokstelsel het 14,67 / 14,61% meer mortaliteite gehad as die gronddamme en hersirkuleringeenheid. Die koi studie se resultate dui aan dat die tipe stelsel het 'n hoogs betekenisvolle (p<0,001) invloed gehad op die gemiddelde toename in lengte van die koi vis vir die somerseisoen. Die tipe dieet het geen invloed op die toename in lengte van koi vis vir al drie die stelsels ge-evalueer, maar die interaksie tussen dieet en die tipe stelsel was wel betekenisvol (p<0.05). Die interaksie tussen die tipe dieet en die tipe stelsel was die hoogste vir die groddamme 136,41 / 32,46 mm en 136,25 / 33,08 mm vir beide tilapia en die koi diëte gevoer. Die gemiddelde totale voer wat deur koi visse in die drie stelsels verbruik is, het wel statisties van mekaar verskil (p<0,05). Koi visse in die gronddam stelsel het meer voer verbruik vir beide die tilapia- en koi dieet (31,03 / 2,01 en 29,67 / 3,57) in vergelyking met die (26,35 / 2,44 ; 26,98 / 0,49 en 5,50 # 0,52 en 6,13 / 0,22) vir die drywende hokke en hersirkuleringseenheid stelsels onderskiedelik. Die % mortaliteite was betekenisvol (p<0,05) vir die verskillende stelsels. Koi visse in die hersirkuleringseenheid het die hoogste mortaliteite gehad vir beide die tilapia en die koi diëte (65,50 / 18,07% en 79,50 / 38,27%) terwyl koi visse in die gronddamme die laagste mortaliteite ondervind het (1,20 / 1,20% en 2,33 / 4,89%) vir beide die tilapia en koi diëte. Die koi in die gronddam stelsel het die beste resultate gelewer en dit is ook moontlik om koi 'n lae waarde dieet te voer sonder nadelige effekte op produksie.
- Full Text:
- Date Issued: 2002
A model for a context aware machine-based personal memory manager and its implementation using a visual programming environment
- Authors: Tsegaye, Melekam Asrat
- Date: 2007
- Subjects: Visual programming (Computer science) Memory management (Computer science) Memory -- Data processing
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4640 , http://hdl.handle.net/10962/d1006563
- Description: Memory is a part of cognition. It is essential for an individual to function normally in society. It encompasses an individual's lifetime experience, thus defining his identity. This thesis develops the concept of a machine-based personal memory manager which captures and manages an individual's day-to-day external memories. Rather than accumulating large amounts of data which has to be mined for useful memories, the machine-based memory manager automatically organizes memories as they are captured to enable their quick retrieval and use. The main functions of the machine-based memory manager envisioned in this thesis are the support and the augmentation of an individual's biological memory system. In the thesis, a model for a machine-based memory manager is developed. A visual programming environment, which can be used to build context aware applications as well as a proof-of-concept machine-based memory manager, is conceptualized and implemented. An experimental machine-based memory manager is implemented and evaluated. The model describes a machine-based memory manager which manages an individual's external memories by context. It addresses the management of external memories which accumulate over long periods of time by proposing a context aware file system which automatically organizes external memories by context. It describes how personal memory management can be facilitated by machine using six entities (life streams, memory producers, memory consumers, a memory manager, memory fragments and context descriptors) and the processes in which these entities participate (memory capture, memory encoding and decoding, memory decoding and retrieval). The visual programming environment represents a development tool which contains facilities that support context aware application programming. For example, it provides facilities which enable the definition and use of virtual sensors. It enables rapid programming with a focus on component re-use and dynamic composition of applications through a visual interface. The experimental machine-based memory manager serves as an example implementation of the machine-based memory manager which is described by the model developed in this thesis. The hardware used in its implementation consists of widely available components such as a camera, microphone and sub-notebook computer which are assembled in the form of a wearable computer. The software is constructed using the visual programming environment developed in this thesis. It contains multiple sensor drivers, context interpreters, a context aware file system as well as memory retrieval and presentation interfaces. The evaluation of the machine-based memory manager shows that it is possible to create a machine which monitors the states of an individual and his environment, and manages his external memories, thus supporting and augmenting his biological memory.
- Full Text:
- Date Issued: 2007
- Authors: Tsegaye, Melekam Asrat
- Date: 2007
- Subjects: Visual programming (Computer science) Memory management (Computer science) Memory -- Data processing
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4640 , http://hdl.handle.net/10962/d1006563
- Description: Memory is a part of cognition. It is essential for an individual to function normally in society. It encompasses an individual's lifetime experience, thus defining his identity. This thesis develops the concept of a machine-based personal memory manager which captures and manages an individual's day-to-day external memories. Rather than accumulating large amounts of data which has to be mined for useful memories, the machine-based memory manager automatically organizes memories as they are captured to enable their quick retrieval and use. The main functions of the machine-based memory manager envisioned in this thesis are the support and the augmentation of an individual's biological memory system. In the thesis, a model for a machine-based memory manager is developed. A visual programming environment, which can be used to build context aware applications as well as a proof-of-concept machine-based memory manager, is conceptualized and implemented. An experimental machine-based memory manager is implemented and evaluated. The model describes a machine-based memory manager which manages an individual's external memories by context. It addresses the management of external memories which accumulate over long periods of time by proposing a context aware file system which automatically organizes external memories by context. It describes how personal memory management can be facilitated by machine using six entities (life streams, memory producers, memory consumers, a memory manager, memory fragments and context descriptors) and the processes in which these entities participate (memory capture, memory encoding and decoding, memory decoding and retrieval). The visual programming environment represents a development tool which contains facilities that support context aware application programming. For example, it provides facilities which enable the definition and use of virtual sensors. It enables rapid programming with a focus on component re-use and dynamic composition of applications through a visual interface. The experimental machine-based memory manager serves as an example implementation of the machine-based memory manager which is described by the model developed in this thesis. The hardware used in its implementation consists of widely available components such as a camera, microphone and sub-notebook computer which are assembled in the form of a wearable computer. The software is constructed using the visual programming environment developed in this thesis. It contains multiple sensor drivers, context interpreters, a context aware file system as well as memory retrieval and presentation interfaces. The evaluation of the machine-based memory manager shows that it is possible to create a machine which monitors the states of an individual and his environment, and manages his external memories, thus supporting and augmenting his biological memory.
- Full Text:
- Date Issued: 2007
Utilising value stream mapping to improve operations at Transwerk Uitenhage
- Authors: Silo, Andile Elliot
- Date: 2006
- Subjects: Production engineering , Production planning
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8760 , http://hdl.handle.net/10948/604 , http://hdl.handle.net/10948/d1011684 , Production engineering , Production planning
- Description: Transwerk is a business uint of Transnet. It was established in 1940. Since 1940 unti 1994, Transwerk operated as the engineering section of Spoornet and was known as South African Railways. Transwerk emancipated in 1994 and had plants in all nine provinces of South Africa. In the past, trains were hauled by steam locomatives, which were manually operated. With the improvement of technology, steam locomotives were replaced by diesel locomotives. The recent technology improvement brought about electric locomotives which are more reliable than diesel locomotives.Trnaswerk has a plant in the Eastern Cape Province which is situated in Uitenhage. This plant focuses on refurbishing wagins for Spoornet. This research is about improving the refurbishing processes of Transwerk Uitenhage.
- Full Text:
- Date Issued: 2006
- Authors: Silo, Andile Elliot
- Date: 2006
- Subjects: Production engineering , Production planning
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8760 , http://hdl.handle.net/10948/604 , http://hdl.handle.net/10948/d1011684 , Production engineering , Production planning
- Description: Transwerk is a business uint of Transnet. It was established in 1940. Since 1940 unti 1994, Transwerk operated as the engineering section of Spoornet and was known as South African Railways. Transwerk emancipated in 1994 and had plants in all nine provinces of South Africa. In the past, trains were hauled by steam locomatives, which were manually operated. With the improvement of technology, steam locomotives were replaced by diesel locomotives. The recent technology improvement brought about electric locomotives which are more reliable than diesel locomotives.Trnaswerk has a plant in the Eastern Cape Province which is situated in Uitenhage. This plant focuses on refurbishing wagins for Spoornet. This research is about improving the refurbishing processes of Transwerk Uitenhage.
- Full Text:
- Date Issued: 2006
A study of four-dimensional oscillator groups and the associated left-invariant control affine systems
- Authors: Biggs, Rory
- Date: 2012
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/164941 , vital:41186
- Description: Thesis (MSc)--Rhodes University, Faculty of Science, Department of Mathematics, 2012
- Full Text:
- Date Issued: 2012
- Authors: Biggs, Rory
- Date: 2012
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/164941 , vital:41186
- Description: Thesis (MSc)--Rhodes University, Faculty of Science, Department of Mathematics, 2012
- Full Text:
- Date Issued: 2012