Investigation of the microstructure of nuclear grade matrix graphite
- Authors: Downey, Justin Michael
- Date: 2009
- Subjects: Graphite -- South Africa , Microstructure , Nanostructured materials -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10540 , http://hdl.handle.net/10948/944 , Graphite -- South Africa , Microstructure , Nanostructured materials -- South Africa
- Description: This dissertation focuses on the investigation of the microstructures of two nuclear grade matrix graphites. These graphites were intended for use in the core components of a high temperature test reactor (HTTR) of the pebble bed modular reactor (PBMR) design. The graphites were provided in the form of fuel spheres and a reflector block. The techniques used in the analysis of the materials include fracturing, etching, scanning electron microscopy (SEM), nano-indentation, x-ray diffraction (XRD) and transmission electron microscopy (TEM). The microstructures of the materials were characterized successfully. The fuel sphere material consisted of a high concentration of curved graphite flakes and grains in contact with turbostratic matrix graphite. The well graphitized flakes and grains were polycrystalline in nature. Delamination cracks were prevalent in the graphite crystallites. There was no significant difference in the microstructures of the center, interior and surface regions of the fuel sphere material. No evidence of amorphous carbon or resin residues was found. The reflector material consisted of a low concentration of graphite crystallites embedded within turbostratic matrix graphite. Delamination cracks were observed within the graphite crystallites, and many cavities were present in the material. TEM observation also revealed the presence of diamond crystallites. It was concluded that the fuel sphere graphite was most probably suitable for use as is, provided that the material also possessed other required properties for use in a HTTR. The reflector material however was considered to be unsuitable for use in a HTTR. It was thus suggested that the reflector material could be made more suitable by sufficient graphitization of the turbostratic graphite which formed the bulk of the material.
- Full Text:
- Date Issued: 2009
- Authors: Downey, Justin Michael
- Date: 2009
- Subjects: Graphite -- South Africa , Microstructure , Nanostructured materials -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10540 , http://hdl.handle.net/10948/944 , Graphite -- South Africa , Microstructure , Nanostructured materials -- South Africa
- Description: This dissertation focuses on the investigation of the microstructures of two nuclear grade matrix graphites. These graphites were intended for use in the core components of a high temperature test reactor (HTTR) of the pebble bed modular reactor (PBMR) design. The graphites were provided in the form of fuel spheres and a reflector block. The techniques used in the analysis of the materials include fracturing, etching, scanning electron microscopy (SEM), nano-indentation, x-ray diffraction (XRD) and transmission electron microscopy (TEM). The microstructures of the materials were characterized successfully. The fuel sphere material consisted of a high concentration of curved graphite flakes and grains in contact with turbostratic matrix graphite. The well graphitized flakes and grains were polycrystalline in nature. Delamination cracks were prevalent in the graphite crystallites. There was no significant difference in the microstructures of the center, interior and surface regions of the fuel sphere material. No evidence of amorphous carbon or resin residues was found. The reflector material consisted of a low concentration of graphite crystallites embedded within turbostratic matrix graphite. Delamination cracks were observed within the graphite crystallites, and many cavities were present in the material. TEM observation also revealed the presence of diamond crystallites. It was concluded that the fuel sphere graphite was most probably suitable for use as is, provided that the material also possessed other required properties for use in a HTTR. The reflector material however was considered to be unsuitable for use in a HTTR. It was thus suggested that the reflector material could be made more suitable by sufficient graphitization of the turbostratic graphite which formed the bulk of the material.
- Full Text:
- Date Issued: 2009
Production of biologically active recombinant HIV-1 protease and intehrase for the purpose of screening medicianl plant extracts
- Authors: Bosch, Janine
- Date: 2009
- Subjects: Medicinal plants -- South Africa , HIV infections -- Alternative treatment -- South Africa , Materia medica, Vegetable -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10325 , http://hdl.handle.net/10948/1056 , Medicinal plants -- South Africa , HIV infections -- Alternative treatment -- South Africa , Materia medica, Vegetable -- South Africa
- Description: Human immunodeficiency virus (HIV) and its gradual weakening of the immune system is an ever growing threat. Acquired immune deficiency syndrome (AIDS), the final stage of HIV, renders a person vulnerable to various opportunistic infections, which in the end lead to death. Apart from intensive vaccine studies, treatment research mainly focuses on preventing the individual HIV enzymes (reverse transcriptase, integrase and protease) from performing their functions. Entry inhibitors, however, block viral entry into the cell, while antisense drugs lock onto the viral genome to keep it from functioning. In this study production of active recombinant HIV-1 protease and integrase was attempted for future drug screening programs. HIV-1 protease was cloned into a pET28b(+) vector and expressed in ROSETTA(DE3)pLysS cells. The protein was purified using a nickel-affinity column utilizing the hexa-histidine tag encoded by the vector. Gel filtration chromatography was attempted after refolding of the protease, but protease yield seemed to decrease with the additional purification step. Partially purified protease was characterized with kinetic studies. Kinetic parameters of HIV-1 protease were determined to be Km = 592 μM, Vmax = 0.59 μM/min and kcat = 31 s-1. HIV-1 integrase, which was cloned into a pET15b vector, was expressed in E. coli BL21(DE3) cells. The coding sequence had been mutated to introduce the amino acid substitutions F185K and C280S, increasing solubility of the protein. The first step in purification of this protein was nickel-affinity chromatography, after which cation exchange chromatography was attempted. HIV-1 integrase concentration was low throughout experiments and no clear elution from the cation exchange column could be observed. A non-radioactive enzyme linked HIV-1 integrase assay failed to detect integrase activity. Modifications to future studies of the integrase are suggested in the chapter involved.
- Full Text:
- Date Issued: 2009
- Authors: Bosch, Janine
- Date: 2009
- Subjects: Medicinal plants -- South Africa , HIV infections -- Alternative treatment -- South Africa , Materia medica, Vegetable -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10325 , http://hdl.handle.net/10948/1056 , Medicinal plants -- South Africa , HIV infections -- Alternative treatment -- South Africa , Materia medica, Vegetable -- South Africa
- Description: Human immunodeficiency virus (HIV) and its gradual weakening of the immune system is an ever growing threat. Acquired immune deficiency syndrome (AIDS), the final stage of HIV, renders a person vulnerable to various opportunistic infections, which in the end lead to death. Apart from intensive vaccine studies, treatment research mainly focuses on preventing the individual HIV enzymes (reverse transcriptase, integrase and protease) from performing their functions. Entry inhibitors, however, block viral entry into the cell, while antisense drugs lock onto the viral genome to keep it from functioning. In this study production of active recombinant HIV-1 protease and integrase was attempted for future drug screening programs. HIV-1 protease was cloned into a pET28b(+) vector and expressed in ROSETTA(DE3)pLysS cells. The protein was purified using a nickel-affinity column utilizing the hexa-histidine tag encoded by the vector. Gel filtration chromatography was attempted after refolding of the protease, but protease yield seemed to decrease with the additional purification step. Partially purified protease was characterized with kinetic studies. Kinetic parameters of HIV-1 protease were determined to be Km = 592 μM, Vmax = 0.59 μM/min and kcat = 31 s-1. HIV-1 integrase, which was cloned into a pET15b vector, was expressed in E. coli BL21(DE3) cells. The coding sequence had been mutated to introduce the amino acid substitutions F185K and C280S, increasing solubility of the protein. The first step in purification of this protein was nickel-affinity chromatography, after which cation exchange chromatography was attempted. HIV-1 integrase concentration was low throughout experiments and no clear elution from the cation exchange column could be observed. A non-radioactive enzyme linked HIV-1 integrase assay failed to detect integrase activity. Modifications to future studies of the integrase are suggested in the chapter involved.
- Full Text:
- Date Issued: 2009
Purification and characterization of serine proteinase inhibitors from two South African indigenous plants, Acacia karoo and Acacia schweinfurthii
- Authors: Odei-Addo, Frank
- Date: 2009
- Subjects: Proteinase -- Inhibitors
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10319 , http://hdl.handle.net/10948/1291 , Proteinase -- Inhibitors
- Description: Serine proteases are known to perform a wide range of functions essential to life; however there has to be some form of control mechanism in place. One of the many control mechanisms is their specific inhibition by protein proteinase inhibitors. Proteinase inhibitors in plants, present in their seeds, participate in defense mechanisms and their production is induced by herbivory or wounding. Plant proteinase inhibitors have been reported to inhibit a variety of serine proteinases, including enzymes of the blood coagulation cascade. In this study, various indigenous seed extracts were screened for potential serine proteinase inhibition. Acacia schweinfurthii was selected as a potential inhibitor that inhibited trypsin and factor X. The AS inhibitor was successfully purified to homogeneity by precipitating with 80 percent (v/v) acetone and the sequential chromatographic steps including ion-exchange chromatography, size exclusion chromatography, affinity purification on a trypsin-agarose column and RP-HPLC. Reducing SDS-PAGE conditions revealed an inhibitor of two polypeptide chains A and B of approximate molecular weights 16 and 10 kDa, respectively, and under non-reducing conditions, 25 kDa was observed. The inhibitor was shown to inhibit trypsin, chymotrypsin and factor X indicating the dynamic nature of the reactive site. An enzyme: inhibitor ratio of 1:1, and a Ki of 3.45nM was determined for the AS inhibitor on trypsin, and the inhibitor also weakly inhibit chymotrypsin. AS inhibitor and STI inhibited factor X with a Ki values of 13.7nM and 77.5μM respectively. Amino acid analysis revealed Mmin values of the A- and B- chain of 15,000 and 7,800, respectively. The effect of seed extracts on the activated partial thrombin time (APTT) and prothrombin time (PT) was tested. No prolongation of the PT was obtained. For the crude extracts of AK and AS, IC200 values of 4.6 and 189.62 μg/mL, were respectively obtained. For the purified fractions of STI, AS and AK, IC200 values of 51.5, 114.31 and 893.8 μg/ml were observed, respectively. Keywords: proteinase inhibitors, Acacia species, trypsin inhibitor, FX inhibitor.
- Full Text:
- Date Issued: 2009
- Authors: Odei-Addo, Frank
- Date: 2009
- Subjects: Proteinase -- Inhibitors
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10319 , http://hdl.handle.net/10948/1291 , Proteinase -- Inhibitors
- Description: Serine proteases are known to perform a wide range of functions essential to life; however there has to be some form of control mechanism in place. One of the many control mechanisms is their specific inhibition by protein proteinase inhibitors. Proteinase inhibitors in plants, present in their seeds, participate in defense mechanisms and their production is induced by herbivory or wounding. Plant proteinase inhibitors have been reported to inhibit a variety of serine proteinases, including enzymes of the blood coagulation cascade. In this study, various indigenous seed extracts were screened for potential serine proteinase inhibition. Acacia schweinfurthii was selected as a potential inhibitor that inhibited trypsin and factor X. The AS inhibitor was successfully purified to homogeneity by precipitating with 80 percent (v/v) acetone and the sequential chromatographic steps including ion-exchange chromatography, size exclusion chromatography, affinity purification on a trypsin-agarose column and RP-HPLC. Reducing SDS-PAGE conditions revealed an inhibitor of two polypeptide chains A and B of approximate molecular weights 16 and 10 kDa, respectively, and under non-reducing conditions, 25 kDa was observed. The inhibitor was shown to inhibit trypsin, chymotrypsin and factor X indicating the dynamic nature of the reactive site. An enzyme: inhibitor ratio of 1:1, and a Ki of 3.45nM was determined for the AS inhibitor on trypsin, and the inhibitor also weakly inhibit chymotrypsin. AS inhibitor and STI inhibited factor X with a Ki values of 13.7nM and 77.5μM respectively. Amino acid analysis revealed Mmin values of the A- and B- chain of 15,000 and 7,800, respectively. The effect of seed extracts on the activated partial thrombin time (APTT) and prothrombin time (PT) was tested. No prolongation of the PT was obtained. For the crude extracts of AK and AS, IC200 values of 4.6 and 189.62 μg/mL, were respectively obtained. For the purified fractions of STI, AS and AK, IC200 values of 51.5, 114.31 and 893.8 μg/ml were observed, respectively. Keywords: proteinase inhibitors, Acacia species, trypsin inhibitor, FX inhibitor.
- Full Text:
- Date Issued: 2009
Purification and partial characterisation of cathepsin D from ostrich skeletal muscle, and its activity during meat maturation
- Authors: Krause, Jason
- Date: 2009
- Subjects: Proteolytic enzymes , Ostrich products industry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10313 , http://hdl.handle.net/10948/1461 , Proteolytic enzymes , Ostrich products industry
- Description: Cathepsin D, a muscle proteinase, participates in lysosomally mediated protein degradation in vivo. This enzyme has been proposed to play a significant role in the postmortem proteolysis process apparently associated with tenderisation. The lack of data on the postmortem characteristics of ostrich meat, especially on the ageing process and its influence on meat tenderness, called for an investigation into this process. There is no data available for purified ostrich cathepsin D, and the aim of this study was, therefore, to isolate, purify and characterise cathepsin D from ostrich skeletal muscle and subsequently investigate the possible role that it may have in the tenderisation process of meat. Cathepsin D was successfully isolated and purified from ostrich skeletal muscle using pepstatin A-agarose chromatography. The purified enzyme was composed of two subunits (14 and 29kDa). The amino acid composition as well as the N-terminal amino acid sequence of both subunits were determined. Kinetic parameters (Km and Vm), thermodynamic parameters (Ea, ∆H, ∆S and ∆G) and functional characteristics (effect of pH, temperature and various inhibitors on cathepsin D activity) were determined and are reported in this study. Ostrich muscle cathepsin D showed a pH optimum of 4 and a temperature optimum of 45°C. The activity of cathepsin D was strongly inhibited by pepstatin A and DTT. Purified ostrich cathepsin D displayed kinetic and functional properties similar to previously reported values from various species. The effect of storage on the activity of cathepsin D was investigated over a 30 day period. It was established that substantial postmortem cathepsin D activity remained throughout the storage period, to implicate cathepsin D, fulfilling a possible role in meat maturation.
- Full Text:
- Date Issued: 2009
- Authors: Krause, Jason
- Date: 2009
- Subjects: Proteolytic enzymes , Ostrich products industry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10313 , http://hdl.handle.net/10948/1461 , Proteolytic enzymes , Ostrich products industry
- Description: Cathepsin D, a muscle proteinase, participates in lysosomally mediated protein degradation in vivo. This enzyme has been proposed to play a significant role in the postmortem proteolysis process apparently associated with tenderisation. The lack of data on the postmortem characteristics of ostrich meat, especially on the ageing process and its influence on meat tenderness, called for an investigation into this process. There is no data available for purified ostrich cathepsin D, and the aim of this study was, therefore, to isolate, purify and characterise cathepsin D from ostrich skeletal muscle and subsequently investigate the possible role that it may have in the tenderisation process of meat. Cathepsin D was successfully isolated and purified from ostrich skeletal muscle using pepstatin A-agarose chromatography. The purified enzyme was composed of two subunits (14 and 29kDa). The amino acid composition as well as the N-terminal amino acid sequence of both subunits were determined. Kinetic parameters (Km and Vm), thermodynamic parameters (Ea, ∆H, ∆S and ∆G) and functional characteristics (effect of pH, temperature and various inhibitors on cathepsin D activity) were determined and are reported in this study. Ostrich muscle cathepsin D showed a pH optimum of 4 and a temperature optimum of 45°C. The activity of cathepsin D was strongly inhibited by pepstatin A and DTT. Purified ostrich cathepsin D displayed kinetic and functional properties similar to previously reported values from various species. The effect of storage on the activity of cathepsin D was investigated over a 30 day period. It was established that substantial postmortem cathepsin D activity remained throughout the storage period, to implicate cathepsin D, fulfilling a possible role in meat maturation.
- Full Text:
- Date Issued: 2009
Raman spectroscopy of ternary III-V semiconducting films
- Authors: Mashigo, Donald
- Date: 2009
- Subjects: Raman spectroscopy , Semiconductor films , Compound semiconductors
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10522 , http://hdl.handle.net/10948/1011 , Raman spectroscopy , Semiconductor films , Compound semiconductors
- Description: The III-V semiconductor compounds (i.e. In Ga As x 1-x , 1 x x InAs Sb - , In Ga Sb x 1-x and Al Ga As x 1-x ) have been studied using room temperature Raman spectroscopy. X-ray diffraction has been used as a complementary characterization technique. In this study all the III-V semiconductor compounds were grown by metal organic chemical vapour deposition (MOCVD) on GaAs and GaSb substrates. The layers were studied with respect to composition, strain variation and critical thickness. Raman spectroscopy has been employed to assess the composition dependence of optical phonons in the layers. The alloy composition was varied, while the thickness was kept constant in order to investigate compositional effects. A significant frequency shift of the phonon modes were observed as the composition changed. The composition dependence of the phonon frequencies were described by linear and polynomial expressions. The results of this study were compared with previous Raman and infrared work on III-V semiconductor compounds. Strain relaxation in InGaAs and InGaSb has been investigated by Raman and X-ray diffraction. Measurements were performed on several series of layers. For each series, the thickness was varied, while keeping the composition constant. For a given composition, the layer thicknesses were such that some layers should be fully strained, some partially relaxed and some fully relaxed. The Raman peak shifts and XRD confirm that a layer grows up to the critical thickness and then releases the strain as the thickness increases. Critical layer thickness values measured in this study were compared with published data, in which various techniques had been used to estimate the critical thickness.
- Full Text:
- Date Issued: 2009
- Authors: Mashigo, Donald
- Date: 2009
- Subjects: Raman spectroscopy , Semiconductor films , Compound semiconductors
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10522 , http://hdl.handle.net/10948/1011 , Raman spectroscopy , Semiconductor films , Compound semiconductors
- Description: The III-V semiconductor compounds (i.e. In Ga As x 1-x , 1 x x InAs Sb - , In Ga Sb x 1-x and Al Ga As x 1-x ) have been studied using room temperature Raman spectroscopy. X-ray diffraction has been used as a complementary characterization technique. In this study all the III-V semiconductor compounds were grown by metal organic chemical vapour deposition (MOCVD) on GaAs and GaSb substrates. The layers were studied with respect to composition, strain variation and critical thickness. Raman spectroscopy has been employed to assess the composition dependence of optical phonons in the layers. The alloy composition was varied, while the thickness was kept constant in order to investigate compositional effects. A significant frequency shift of the phonon modes were observed as the composition changed. The composition dependence of the phonon frequencies were described by linear and polynomial expressions. The results of this study were compared with previous Raman and infrared work on III-V semiconductor compounds. Strain relaxation in InGaAs and InGaSb has been investigated by Raman and X-ray diffraction. Measurements were performed on several series of layers. For each series, the thickness was varied, while keeping the composition constant. For a given composition, the layer thicknesses were such that some layers should be fully strained, some partially relaxed and some fully relaxed. The Raman peak shifts and XRD confirm that a layer grows up to the critical thickness and then releases the strain as the thickness increases. Critical layer thickness values measured in this study were compared with published data, in which various techniques had been used to estimate the critical thickness.
- Full Text:
- Date Issued: 2009
Reeds as indicators of nutrient enrichment in the East Kleinemonde Estuary
- Authors: Human, Lucienne Ryno Daniel
- Date: 2009
- Subjects: Estuaries -- South Africa -- Eastern Cape -- East Kleinemonde Estuary , Nutrient cycles -- South Africa -- Eastern Cape -- East Kleinemonde Estuary
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10615 , http://hdl.handle.net/10948/1252 , Estuaries -- South Africa -- Eastern Cape -- East Kleinemonde Estuary , Nutrient cycles -- South Africa -- Eastern Cape -- East Kleinemonde Estuary
- Description: The release of nutrients (nitrogen and phosphorus) via land clearing, application of fertilisers, discharge of human waste and combustion of fossil fuels, is one of the most harmful effects of anthropogenic stresses on aquatic environments. This study investigated the use of reeds as indicators of nutrient input to estuaries. Small estuaries such as the oligotrophic East Kleinemonde where the research was mostly conducted are sensitive to nutrient enrichment from septic tanks, stormwater runoff and fertiliser application to lawns in close proximity to the estuary. Nutrient concentrations were sampled at different positions, in the groundwater, at the water’s edge, in the reed bed and in the main estuary channel at five sites in the East Kleinemonde Estuary. The NH4+ and SRP concentrations showed a definite trend as concentrations decreased from the groundwater or water’s edge into the main estuary channel. Groundwater introduced nutrients to the estuary which were then taken up by the fringing reeds (Phragmites australis (Cavinelles) Trinius ex Steudel). The water column nutrients were either below detectable limits or in very low concentrations. Low TOxN concentrations were consistently found at the different sites and probably resulted from P. australis assimilating N-TOxN for growth more efficiently than N- NH4+. The roots, rhizomes, stems and leaves of the reeds were measured for δ15N as an indicator of nutrient enrichment as nitrogen stable isotope analysis of plant tissue is an effective method for assessing and monitoring septic tank and other anthropogenic inputs. All plant parts for the three sampling sessions at Site 1 (mouth region) in the East Kleinemonde Estuary had significantly higher δ15N signatures (~20 percent) than the leaves at Site 5 (upper reaches). These differences were related to the surrounding land-use of the East Kleinemonde catchment, where the lower part of the estuary has moderate to low residential development and the upper reaches are utilized mainly for livestock farming. The high δ15N signatures at Site 1 were attributed to septic tank wastewater and stormwater run-off entering the estuary. Nutrient enrichment also influenced the morphology of the reeds. Reed biomass, height and stem density was significantly higher at Site 1 compared to Site 5. Similar studies were conducted in August 2008 in the Sundays Estuary and October 2008 in the nearby Mtati and Mpekweni estuaries to see if the results were similar. iii The same patterns were found where the groundwater NH4+ and SRP concentrations were higher than the estuary channel in the Mtati and Mpekweni estuaries. In the Mpekweni and Sundays estuaries Phragmites australis leaves had high δ15N signatures (10 and 11 percent) similar to that of Site 1 in the East Kleinemonde Estuary. Lower signatures (-2 to +4 percent) were found in the Mtati Estuary. This sampling site was sheltered by a bridge with a steep slope and the concentrations were similar to Site 3 and 5 in the East Kleinemonde Estuary where the derived nutrient was the result of stormwater runoff or fertilisers. Density and biomass of reeds in the Sundays and East Kleinemonde (Site 1) estuaries were similar and this could be related to different nutrient sources, agricultural return flow and septic tank input respectively. Reeds in the Sundays Estuary were significantly taller than in the other estuaries which showed that factors such as shelter and salinity also influence reed growth and therefore morphology alone would not be a good indicator of nutrient enrichment. Indicators of nutrient enrichment are important as the status of temporarily open / closed estuaries in South Africa is threatened by deteriorating water quality. Measurements of the water column may provide an inaccurate assessment of water quality whereas macrophytes are outstanding potential indicators of nutrient enrichment as they are widely distributed, abundant and long-lived. The findings from this study indicate that δ15N concentrations in reeds can be used to indicate nutrient loading.
- Full Text:
- Date Issued: 2009
- Authors: Human, Lucienne Ryno Daniel
- Date: 2009
- Subjects: Estuaries -- South Africa -- Eastern Cape -- East Kleinemonde Estuary , Nutrient cycles -- South Africa -- Eastern Cape -- East Kleinemonde Estuary
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10615 , http://hdl.handle.net/10948/1252 , Estuaries -- South Africa -- Eastern Cape -- East Kleinemonde Estuary , Nutrient cycles -- South Africa -- Eastern Cape -- East Kleinemonde Estuary
- Description: The release of nutrients (nitrogen and phosphorus) via land clearing, application of fertilisers, discharge of human waste and combustion of fossil fuels, is one of the most harmful effects of anthropogenic stresses on aquatic environments. This study investigated the use of reeds as indicators of nutrient input to estuaries. Small estuaries such as the oligotrophic East Kleinemonde where the research was mostly conducted are sensitive to nutrient enrichment from septic tanks, stormwater runoff and fertiliser application to lawns in close proximity to the estuary. Nutrient concentrations were sampled at different positions, in the groundwater, at the water’s edge, in the reed bed and in the main estuary channel at five sites in the East Kleinemonde Estuary. The NH4+ and SRP concentrations showed a definite trend as concentrations decreased from the groundwater or water’s edge into the main estuary channel. Groundwater introduced nutrients to the estuary which were then taken up by the fringing reeds (Phragmites australis (Cavinelles) Trinius ex Steudel). The water column nutrients were either below detectable limits or in very low concentrations. Low TOxN concentrations were consistently found at the different sites and probably resulted from P. australis assimilating N-TOxN for growth more efficiently than N- NH4+. The roots, rhizomes, stems and leaves of the reeds were measured for δ15N as an indicator of nutrient enrichment as nitrogen stable isotope analysis of plant tissue is an effective method for assessing and monitoring septic tank and other anthropogenic inputs. All plant parts for the three sampling sessions at Site 1 (mouth region) in the East Kleinemonde Estuary had significantly higher δ15N signatures (~20 percent) than the leaves at Site 5 (upper reaches). These differences were related to the surrounding land-use of the East Kleinemonde catchment, where the lower part of the estuary has moderate to low residential development and the upper reaches are utilized mainly for livestock farming. The high δ15N signatures at Site 1 were attributed to septic tank wastewater and stormwater run-off entering the estuary. Nutrient enrichment also influenced the morphology of the reeds. Reed biomass, height and stem density was significantly higher at Site 1 compared to Site 5. Similar studies were conducted in August 2008 in the Sundays Estuary and October 2008 in the nearby Mtati and Mpekweni estuaries to see if the results were similar. iii The same patterns were found where the groundwater NH4+ and SRP concentrations were higher than the estuary channel in the Mtati and Mpekweni estuaries. In the Mpekweni and Sundays estuaries Phragmites australis leaves had high δ15N signatures (10 and 11 percent) similar to that of Site 1 in the East Kleinemonde Estuary. Lower signatures (-2 to +4 percent) were found in the Mtati Estuary. This sampling site was sheltered by a bridge with a steep slope and the concentrations were similar to Site 3 and 5 in the East Kleinemonde Estuary where the derived nutrient was the result of stormwater runoff or fertilisers. Density and biomass of reeds in the Sundays and East Kleinemonde (Site 1) estuaries were similar and this could be related to different nutrient sources, agricultural return flow and septic tank input respectively. Reeds in the Sundays Estuary were significantly taller than in the other estuaries which showed that factors such as shelter and salinity also influence reed growth and therefore morphology alone would not be a good indicator of nutrient enrichment. Indicators of nutrient enrichment are important as the status of temporarily open / closed estuaries in South Africa is threatened by deteriorating water quality. Measurements of the water column may provide an inaccurate assessment of water quality whereas macrophytes are outstanding potential indicators of nutrient enrichment as they are widely distributed, abundant and long-lived. The findings from this study indicate that δ15N concentrations in reeds can be used to indicate nutrient loading.
- Full Text:
- Date Issued: 2009
Seed dynamics and seedling survival in mainland thicket of the Eastern Cape
- Weatherall-Thomas, Clayton Richard
- Authors: Weatherall-Thomas, Clayton Richard
- Date: 2009
- Subjects: Seeds -- Growth , Germination , Seedlings -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10601 , http://hdl.handle.net/10948/1048 , Seeds -- Growth , Germination , Seedlings -- South Africa -- Eastern Cape
- Description: Subtropical Thicket is the dominant vegetation biome in the Eastern Cape. Little regeneration through seedlings has been observed in Thicket. This is of serious concern, as Thicket has been degraded over large areas of its distribution. An understanding of the seed dynamics is necessary for any restoration project. A number of possible causes for the lack of seedlings were therefore investigated. Study sites were best classified according to the biogeographical regions of the Subtropical Thicket Ecosystem Planning (STEP) project. The seed bank of Thicket is dissimilar to the aboveground vegetation, as it lacks woody species and is dominated by herbs and grasses, making little contribution to the regeneration of Thicket species. An increase in canopy cover resulted in lower soil and air temperatures, as well as light, and an increase in litter depth. Seedling abundance and species richness increases with mean annual rainfall, with woody seedlings being dominant in the higher rainfall areas, and succulent species in the lower rainfall regions. Anemochorous species dominated the germinable seed bank, and zoochorous species were more prevalent underneath the canopy, compared to open areas, an indication of active seed dispersal. No germination was recorded in many Thicket species, and dormancy mechanisms were lacking in many of the species that did germinate. Immersion in hot water increased germination in the hard seeds of Acacia karroo, whereas shade enhanced germination in small seeded Burchellia bubalina. The response of seedlings of four Thicket species with varying distribution to shade and drought was studied. Ptaeroxylon obliquum and Aloe africana are drought tolerant species, whereas Burchellia bubalina and Rhus dentata were intolerant to low soil moisture. All four species were able to grow in deep shade, although Rhus dentata would be classified as a shade avoider, unlike the other three species that are shade tolerant. This results in the four species having different regeneration niches. It was concluded that dispersal and the lack of “safe sites” for seedlings were the main limitations to seedling establishment in Mainland Thicket.
- Full Text:
- Date Issued: 2009
- Authors: Weatherall-Thomas, Clayton Richard
- Date: 2009
- Subjects: Seeds -- Growth , Germination , Seedlings -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10601 , http://hdl.handle.net/10948/1048 , Seeds -- Growth , Germination , Seedlings -- South Africa -- Eastern Cape
- Description: Subtropical Thicket is the dominant vegetation biome in the Eastern Cape. Little regeneration through seedlings has been observed in Thicket. This is of serious concern, as Thicket has been degraded over large areas of its distribution. An understanding of the seed dynamics is necessary for any restoration project. A number of possible causes for the lack of seedlings were therefore investigated. Study sites were best classified according to the biogeographical regions of the Subtropical Thicket Ecosystem Planning (STEP) project. The seed bank of Thicket is dissimilar to the aboveground vegetation, as it lacks woody species and is dominated by herbs and grasses, making little contribution to the regeneration of Thicket species. An increase in canopy cover resulted in lower soil and air temperatures, as well as light, and an increase in litter depth. Seedling abundance and species richness increases with mean annual rainfall, with woody seedlings being dominant in the higher rainfall areas, and succulent species in the lower rainfall regions. Anemochorous species dominated the germinable seed bank, and zoochorous species were more prevalent underneath the canopy, compared to open areas, an indication of active seed dispersal. No germination was recorded in many Thicket species, and dormancy mechanisms were lacking in many of the species that did germinate. Immersion in hot water increased germination in the hard seeds of Acacia karroo, whereas shade enhanced germination in small seeded Burchellia bubalina. The response of seedlings of four Thicket species with varying distribution to shade and drought was studied. Ptaeroxylon obliquum and Aloe africana are drought tolerant species, whereas Burchellia bubalina and Rhus dentata were intolerant to low soil moisture. All four species were able to grow in deep shade, although Rhus dentata would be classified as a shade avoider, unlike the other three species that are shade tolerant. This results in the four species having different regeneration niches. It was concluded that dispersal and the lack of “safe sites” for seedlings were the main limitations to seedling establishment in Mainland Thicket.
- Full Text:
- Date Issued: 2009
Size prediction for plus-size women's intimate apparel using a 3D body scanner
- Authors: Pandarum, Krishnavellie
- Date: 2009
- Subjects: Lingerie , Lingerie -- Design , Overweight women
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10450 , http://hdl.handle.net/10948/1153 , http://hdl.handle.net/10948/d1012020 , Lingerie , Lingerie -- Design , Overweight women
- Description: Garment “fitting” from tailor-made to ready-to-wear clothing, has evolved over time. Ready to-wear and standardized sizes appeared in the middle 19th century. Today garment fitting is one of the most important criteria in the consumer buying decision making process. This is particularly so with “body hugging” garments, such as intimate apparel; or the bra that moulds the form of the wearer to produce “smooth” outer garment silhouettes. The South African bra retailer and manufacturers sizing charts are generally based upon body dimension data collected using traditional anthropometric methods. Professional measurers are not able to capture the hidden areas of the breast such as the inframmatory fold line, the volume, shape and contour of the breast using tape measures, calipers and other measuring devices. Traditional anthropometry also does not have the ability to systemically observe the bottom line of the breast base and extract accurate data on breast volume which are key factors in designing underwire bras and in the pattern making of the bra cup panels. Exploratory retail and consumer studies have indicated that consumers, notably plus size women, experience considerable problems and dissatisfaction with poorly fitting bras. There is therefore clearly a need in South Africa to conduct a 3D anthropometric study, focusing especially on the plus-sized women’s bra market segment, as there is very little or limited studies, to date, conduct for this market segment of the population. This pilot study collected 3D torso body measurement data from a convenient sample of 176 plus sized women, recruited from Playtex (Pty) Ltd. situated in Durban, KwaZulu Natal, South Africa. The study evaluates the 3D breast volume measurement data extraction process, using an expert system developed by [TC]2 integrated into the propriety NX12-3D full body scanner software and that taken using the traditional dress-makers tape-measure. The objective is to establish the relationship between the 3D torso and breast volume data measurement output as extracted by the expert system when compared to the South African bra manufacturers sizing chart, for use in pattern making for bra cup panel designs and in the designing of underwire bras for large breasted or plus size women. The results contained in this dissertation cannot be extrapolated to the larger population of South Africa and is limited to the 176 plus size women selected by Body Mass Index; recruited from KwaZulu Natal, South Africa.
- Full Text:
- Date Issued: 2009
- Authors: Pandarum, Krishnavellie
- Date: 2009
- Subjects: Lingerie , Lingerie -- Design , Overweight women
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10450 , http://hdl.handle.net/10948/1153 , http://hdl.handle.net/10948/d1012020 , Lingerie , Lingerie -- Design , Overweight women
- Description: Garment “fitting” from tailor-made to ready-to-wear clothing, has evolved over time. Ready to-wear and standardized sizes appeared in the middle 19th century. Today garment fitting is one of the most important criteria in the consumer buying decision making process. This is particularly so with “body hugging” garments, such as intimate apparel; or the bra that moulds the form of the wearer to produce “smooth” outer garment silhouettes. The South African bra retailer and manufacturers sizing charts are generally based upon body dimension data collected using traditional anthropometric methods. Professional measurers are not able to capture the hidden areas of the breast such as the inframmatory fold line, the volume, shape and contour of the breast using tape measures, calipers and other measuring devices. Traditional anthropometry also does not have the ability to systemically observe the bottom line of the breast base and extract accurate data on breast volume which are key factors in designing underwire bras and in the pattern making of the bra cup panels. Exploratory retail and consumer studies have indicated that consumers, notably plus size women, experience considerable problems and dissatisfaction with poorly fitting bras. There is therefore clearly a need in South Africa to conduct a 3D anthropometric study, focusing especially on the plus-sized women’s bra market segment, as there is very little or limited studies, to date, conduct for this market segment of the population. This pilot study collected 3D torso body measurement data from a convenient sample of 176 plus sized women, recruited from Playtex (Pty) Ltd. situated in Durban, KwaZulu Natal, South Africa. The study evaluates the 3D breast volume measurement data extraction process, using an expert system developed by [TC]2 integrated into the propriety NX12-3D full body scanner software and that taken using the traditional dress-makers tape-measure. The objective is to establish the relationship between the 3D torso and breast volume data measurement output as extracted by the expert system when compared to the South African bra manufacturers sizing chart, for use in pattern making for bra cup panel designs and in the designing of underwire bras for large breasted or plus size women. The results contained in this dissertation cannot be extrapolated to the larger population of South Africa and is limited to the 176 plus size women selected by Body Mass Index; recruited from KwaZulu Natal, South Africa.
- Full Text:
- Date Issued: 2009
Socio-economic and ecological correlates of leopard-stock farmer conflict in the Baviaanskloof mega-reserve, Eastern Cape
- Authors: Minnie, Liaan
- Date: 2009
- Subjects: Leopard -- Ecology -- South Africa -- Eastern Cape , Leopard -- Conservation -- South Africa -- Baviaanskloof , Leopard -- Conservation -- South Africa -- Eastern Cape , Wildlife conservation -- South Africa -- Eastern Cape , Leopard -- Effect of human beings on
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10702 , http://hdl.handle.net/10948/1044 , Leopard -- Ecology -- South Africa -- Eastern Cape , Leopard -- Conservation -- South Africa -- Baviaanskloof , Leopard -- Conservation -- South Africa -- Eastern Cape , Wildlife conservation -- South Africa -- Eastern Cape , Leopard -- Effect of human beings on
- Description: The leopard, Panthera pardus, is particularly threatened outside conservation areas in South Africa. This has been attributed to a reduction in natural habitat, decreasing natural prey populations, and commercial exploitation such as trophy hunting, and most importantly, persecution by stock farmers (Woodroffe 2001). The leopard population in the Baviaanskloof Mega-Reserve (BMR) has undergone a substantial decrease in range and numbers in the past 200 years, resulting in a highly fragmented population in the Baviaanskloof Mega-Reserve, and is regarded as being insecure. There is thus a need to investigate the nature and extent of leopard-stock farmer interactions to provide the foundation for an effective leopard conservation plan. Here I investigated the ecological and socio-economic factors influencing leopard-stock farmer conflict via landowner surveys and estimated potential leopard numbers using a prey-based density model. Leopards are not necessarily the most important causes of livestock mortality in the BMR. On average, leopards killed significantly less livestock (0.7 percent livestock per year) than black-backed jackals (4.7 percent per year) and caracal (2.5 percent per year), yet 67 percent of farmers had negative attitudes towards leopards. These negative attitudes were not significantly related to stock losses. However, most of the farmers that had negative attitudes towards leopards did not have any stock losses attributed to leopards. Thus if predator-stock conflict is not reduced it will result in the retaliatory killing of leopards. This will have severe consequences for this relatively small population (estimated at 59 – 104 individuals by the prey-based model), which may ultimately lead to the local extinction of these leopards (Woodroffe & Ginsberg 1998).
- Full Text:
- Date Issued: 2009
- Authors: Minnie, Liaan
- Date: 2009
- Subjects: Leopard -- Ecology -- South Africa -- Eastern Cape , Leopard -- Conservation -- South Africa -- Baviaanskloof , Leopard -- Conservation -- South Africa -- Eastern Cape , Wildlife conservation -- South Africa -- Eastern Cape , Leopard -- Effect of human beings on
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10702 , http://hdl.handle.net/10948/1044 , Leopard -- Ecology -- South Africa -- Eastern Cape , Leopard -- Conservation -- South Africa -- Baviaanskloof , Leopard -- Conservation -- South Africa -- Eastern Cape , Wildlife conservation -- South Africa -- Eastern Cape , Leopard -- Effect of human beings on
- Description: The leopard, Panthera pardus, is particularly threatened outside conservation areas in South Africa. This has been attributed to a reduction in natural habitat, decreasing natural prey populations, and commercial exploitation such as trophy hunting, and most importantly, persecution by stock farmers (Woodroffe 2001). The leopard population in the Baviaanskloof Mega-Reserve (BMR) has undergone a substantial decrease in range and numbers in the past 200 years, resulting in a highly fragmented population in the Baviaanskloof Mega-Reserve, and is regarded as being insecure. There is thus a need to investigate the nature and extent of leopard-stock farmer interactions to provide the foundation for an effective leopard conservation plan. Here I investigated the ecological and socio-economic factors influencing leopard-stock farmer conflict via landowner surveys and estimated potential leopard numbers using a prey-based density model. Leopards are not necessarily the most important causes of livestock mortality in the BMR. On average, leopards killed significantly less livestock (0.7 percent livestock per year) than black-backed jackals (4.7 percent per year) and caracal (2.5 percent per year), yet 67 percent of farmers had negative attitudes towards leopards. These negative attitudes were not significantly related to stock losses. However, most of the farmers that had negative attitudes towards leopards did not have any stock losses attributed to leopards. Thus if predator-stock conflict is not reduced it will result in the retaliatory killing of leopards. This will have severe consequences for this relatively small population (estimated at 59 – 104 individuals by the prey-based model), which may ultimately lead to the local extinction of these leopards (Woodroffe & Ginsberg 1998).
- Full Text:
- Date Issued: 2009
Solvent-free synthesis of bisferrocenylimines and their coordination to rhodium (I)
- Authors: Kleyi, Phumelele Eldridge
- Date: 2009
- Subjects: Organic compounds -- Synthesis , Organic solvents , Solution (Chemistry) , Chemistry, Organic , Coordination compounds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10393 , http://hdl.handle.net/10948/1053 , Organic compounds -- Synthesis , Organic solvents , Solution (Chemistry) , Chemistry, Organic , Coordination compounds
- Description: Solvent-free reactions possess advantages compared to the solvent route, such as shorter reaction times, less use of energy, better yields, etc. Herein, the synthesis and characterization of bisferrocenylimines and arylbisamines are described. Reduction of the above compounds with LAH resulted in the formation of bisferrocenylamines and arylbisamines, respectively. The coordination chemistry of all the above compounds to rhodium(I) is also discussed in the prepared complexes [Rh(COD)(NN)]ClO4, where NN = bisferrocenylimines, and [Rh(COD)(NN)]BF4, where NN = bisferrocenylamines and arylbisamines. X-ray crystal structures of the complexes [Rh(COD)(NN)]ClO4 ([3.2] and [3.3]) have been obtained. Complexes of the type [Rh(COD)(NN)]BF4 were characterized with IR and UV-vis spectroscopy, cyclic voltammetry and conductometry. The catalytic activity of the complexes was also investigated: [Rh(COD)(NN)]ClO4 for the polymerization of phenylacetylene and [Rh(COD)(NN)]BF4 for the hydroformylation of styrene.
- Full Text:
- Date Issued: 2009
- Authors: Kleyi, Phumelele Eldridge
- Date: 2009
- Subjects: Organic compounds -- Synthesis , Organic solvents , Solution (Chemistry) , Chemistry, Organic , Coordination compounds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10393 , http://hdl.handle.net/10948/1053 , Organic compounds -- Synthesis , Organic solvents , Solution (Chemistry) , Chemistry, Organic , Coordination compounds
- Description: Solvent-free reactions possess advantages compared to the solvent route, such as shorter reaction times, less use of energy, better yields, etc. Herein, the synthesis and characterization of bisferrocenylimines and arylbisamines are described. Reduction of the above compounds with LAH resulted in the formation of bisferrocenylamines and arylbisamines, respectively. The coordination chemistry of all the above compounds to rhodium(I) is also discussed in the prepared complexes [Rh(COD)(NN)]ClO4, where NN = bisferrocenylimines, and [Rh(COD)(NN)]BF4, where NN = bisferrocenylamines and arylbisamines. X-ray crystal structures of the complexes [Rh(COD)(NN)]ClO4 ([3.2] and [3.3]) have been obtained. Complexes of the type [Rh(COD)(NN)]BF4 were characterized with IR and UV-vis spectroscopy, cyclic voltammetry and conductometry. The catalytic activity of the complexes was also investigated: [Rh(COD)(NN)]ClO4 for the polymerization of phenylacetylene and [Rh(COD)(NN)]BF4 for the hydroformylation of styrene.
- Full Text:
- Date Issued: 2009
Statistical models for pricing weather derivatives for Port Elizabeth
- Authors: Nasila, Mark Wopicho
- Date: 2009
- Subjects: Weather derivatives -- Prices -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10567 , http://hdl.handle.net/10948/1018 , Weather derivatives -- Prices -- South Africa -- Port Elizabeth
- Description: Weather has a significant impact on business activities of many kinds. The list of economic activities subjected to the risk of the weather include: the energy producers and consumers, the industry of leisure, the insurance industry, the food industry and the agricultural industries but the primary industry, namely the energy industry, has given rise to the demand for weather derivatives and has caused the weather risk management industry to evolve actively. A derivative is a contract or security, whose payoffs depend upon the price of an underlying asset price, and is used to control the risks of naturally-arising exposures to such an asset price. Therefore weather derivatives are financial contracts with payouts that depend on weather in some form. It is a contract that provides a payoff in response to an index level based on weather phenomena (West, 2002).The underlying variable can be for example humidity, rain, snowfall, temperature, or even sunshine. The main players who take part in the weather derivatives markets industry can be grouped in to five main categories, namely: 1) End users who are also referred to as hedgers 2) Speculators 3) Market makers 4) Brokers 5) Insurance and re-insurance companies. Since the late 90’s when the first weather derivatives transactions were recorded, the underlying market has witnessed the development of a new derivative market in the United States, which is gradually expanding across Europe. However, the newly developed market for weather derivatives is not liquid in Africa and specifically South Africa mainly due to the following factors: 1) Many companies and business organisations have not yet established a hedging policy or even figured out how their businesses or industries are exposed to weather risks. 2 2) “Since many companies and industries depend on insurance companies to cover their risks, it is possible that the solutions suggested by these companies or industries looking for protection from weather risks differ according to the cover provided by these insurance organisations “(Micali, 2008). The main aim of this study is to review available statistical models for pricing derivatives, with temperature as the underlying which could enable industries, businesses and other organisations in South Africa to protect themselves against losses due to fluctuations in the weather and therefore hedge their risks.
- Full Text:
- Date Issued: 2009
- Authors: Nasila, Mark Wopicho
- Date: 2009
- Subjects: Weather derivatives -- Prices -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10567 , http://hdl.handle.net/10948/1018 , Weather derivatives -- Prices -- South Africa -- Port Elizabeth
- Description: Weather has a significant impact on business activities of many kinds. The list of economic activities subjected to the risk of the weather include: the energy producers and consumers, the industry of leisure, the insurance industry, the food industry and the agricultural industries but the primary industry, namely the energy industry, has given rise to the demand for weather derivatives and has caused the weather risk management industry to evolve actively. A derivative is a contract or security, whose payoffs depend upon the price of an underlying asset price, and is used to control the risks of naturally-arising exposures to such an asset price. Therefore weather derivatives are financial contracts with payouts that depend on weather in some form. It is a contract that provides a payoff in response to an index level based on weather phenomena (West, 2002).The underlying variable can be for example humidity, rain, snowfall, temperature, or even sunshine. The main players who take part in the weather derivatives markets industry can be grouped in to five main categories, namely: 1) End users who are also referred to as hedgers 2) Speculators 3) Market makers 4) Brokers 5) Insurance and re-insurance companies. Since the late 90’s when the first weather derivatives transactions were recorded, the underlying market has witnessed the development of a new derivative market in the United States, which is gradually expanding across Europe. However, the newly developed market for weather derivatives is not liquid in Africa and specifically South Africa mainly due to the following factors: 1) Many companies and business organisations have not yet established a hedging policy or even figured out how their businesses or industries are exposed to weather risks. 2 2) “Since many companies and industries depend on insurance companies to cover their risks, it is possible that the solutions suggested by these companies or industries looking for protection from weather risks differ according to the cover provided by these insurance organisations “(Micali, 2008). The main aim of this study is to review available statistical models for pricing derivatives, with temperature as the underlying which could enable industries, businesses and other organisations in South Africa to protect themselves against losses due to fluctuations in the weather and therefore hedge their risks.
- Full Text:
- Date Issued: 2009
Statistical relationship of customer behavioral characteristics in personal banking
- Authors: Rasuba, Maanda
- Date: 2009
- Subjects: Customer relations -- South Africa -- Management , Consumer behavior -- South Africa , Banks and banking -- Customer services -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10566 , http://hdl.handle.net/10948/1165 , Customer relations -- South Africa -- Management , Consumer behavior -- South Africa , Banks and banking -- Customer services -- South Africa
- Description: This study investigates the relationship of bank customers’ behavioural patterns based on the customers past transactions, with respect to their profile characteristics. The main aim of this study is to illustrate that different categories of customers (based on demographical variables such as race, gender and age) have statistically significant differences in behaviour, with respect to how they operate their accounts. A theoretical overview on the literature of customer relationship management in the banking sector emphasises the importance of understanding customers to ensure that a business is successful. Four null-hypotheses where formulated based on a general research hypothesis. The data base provided a major South African bank is used to achieve the objectives. Extensive cleaning of the data set was necessary to ensure the validity of the results. The data set had 7860 customer keys. The large data base used contributed to the reliability of the results. The following behavioural variables were used in the study namely, transaction data, average debit and credit transaction amounts and average number of transactions per month. The main results of study indicate that different customer categories have statistically significant differences in behaviour, with respect to how customers operate their accounts. This implies that it is important for the banking sector to consider customer gender differences, age differences and race group differences in the relationship strategies which they employ in their multicultural environment. Further research in the area may be necessary before generalisation can be made on all banking customers.
- Full Text:
- Date Issued: 2009
- Authors: Rasuba, Maanda
- Date: 2009
- Subjects: Customer relations -- South Africa -- Management , Consumer behavior -- South Africa , Banks and banking -- Customer services -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10566 , http://hdl.handle.net/10948/1165 , Customer relations -- South Africa -- Management , Consumer behavior -- South Africa , Banks and banking -- Customer services -- South Africa
- Description: This study investigates the relationship of bank customers’ behavioural patterns based on the customers past transactions, with respect to their profile characteristics. The main aim of this study is to illustrate that different categories of customers (based on demographical variables such as race, gender and age) have statistically significant differences in behaviour, with respect to how they operate their accounts. A theoretical overview on the literature of customer relationship management in the banking sector emphasises the importance of understanding customers to ensure that a business is successful. Four null-hypotheses where formulated based on a general research hypothesis. The data base provided a major South African bank is used to achieve the objectives. Extensive cleaning of the data set was necessary to ensure the validity of the results. The data set had 7860 customer keys. The large data base used contributed to the reliability of the results. The following behavioural variables were used in the study namely, transaction data, average debit and credit transaction amounts and average number of transactions per month. The main results of study indicate that different customer categories have statistically significant differences in behaviour, with respect to how customers operate their accounts. This implies that it is important for the banking sector to consider customer gender differences, age differences and race group differences in the relationship strategies which they employ in their multicultural environment. Further research in the area may be necessary before generalisation can be made on all banking customers.
- Full Text:
- Date Issued: 2009
Synthesis and characterization of novel platinum complexes : their anticancer behaviour
- Authors: Myburgh, Jolanda
- Date: 2009
- Subjects: Complex compounds -- Synthesis , Platinum compounds , Antineoplastic agents
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10429 , http://hdl.handle.net/10948/d1018621
- Description: In this dissertation novel non-leaving groups were employed to synthesize platinum complexes which can contribute to the understanding or improvement of anticancer action. These complexes basically consist of (NS)-chelate and amineplatinum complexes. Bidentate (NS)-donor ligands were used as non-leaving ligands in the syntheses of platinum(II) complexes with iodide, chloride, bromide and oxalate anions as leaving groups. These complexes were synthesized and studied since many questions regarding the interaction of sulfur donors and platinum still exists. These relate to thermodynamic and kinetic factors and their influence on anticancer action. In this dissertation the properties of novel platinum(II) complexes of a bidentate ligand having an aromatic nitrogen-donor atom in combination with a thioethereal sulfur atom capable of forming a five membered ring with platinum(II) were studied. The general structure of the (NS) -ligands used were N-alkyl-2-methylthioalkyl imidazole. Alkyl groups used were methyl, ethyl and propyl. Although amine complexes of platinum have been extensively studied there are some new aspects of these that are worthwhile investigating. In this dissertation amines having planar attachments which will be at an angle with the coordination plane viz. benzylamine and amines having cyclic aliphatic groups namely cyclopropyl and cyclohexyl were investigated. Some of the (NS) - and amineplatinum(II) complexes were oxidised to their mononitroplatinum(IV) analogues . The motivation for the synthesis of these complexes was the greater kinetic stability of platinum(IV) and recent research has shown that a specific type of platinum(IV) compound shows suitable properties as an anticancer agent. These complexes were characterised by a variety of spectral means (IR, NMR, mass spectroscopy) as well as elemental analysis, solubility determinations, thermal analysis (TGA), ionization studies and finally their anticancer behaviour towards three different cell lines(Hela, MCF 7, Ht29) and in this process they were compared to the behaviour of cisplatin as a reference. A few have shown promising anticancer behaviour.
- Full Text:
- Date Issued: 2009
- Authors: Myburgh, Jolanda
- Date: 2009
- Subjects: Complex compounds -- Synthesis , Platinum compounds , Antineoplastic agents
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10429 , http://hdl.handle.net/10948/d1018621
- Description: In this dissertation novel non-leaving groups were employed to synthesize platinum complexes which can contribute to the understanding or improvement of anticancer action. These complexes basically consist of (NS)-chelate and amineplatinum complexes. Bidentate (NS)-donor ligands were used as non-leaving ligands in the syntheses of platinum(II) complexes with iodide, chloride, bromide and oxalate anions as leaving groups. These complexes were synthesized and studied since many questions regarding the interaction of sulfur donors and platinum still exists. These relate to thermodynamic and kinetic factors and their influence on anticancer action. In this dissertation the properties of novel platinum(II) complexes of a bidentate ligand having an aromatic nitrogen-donor atom in combination with a thioethereal sulfur atom capable of forming a five membered ring with platinum(II) were studied. The general structure of the (NS) -ligands used were N-alkyl-2-methylthioalkyl imidazole. Alkyl groups used were methyl, ethyl and propyl. Although amine complexes of platinum have been extensively studied there are some new aspects of these that are worthwhile investigating. In this dissertation amines having planar attachments which will be at an angle with the coordination plane viz. benzylamine and amines having cyclic aliphatic groups namely cyclopropyl and cyclohexyl were investigated. Some of the (NS) - and amineplatinum(II) complexes were oxidised to their mononitroplatinum(IV) analogues . The motivation for the synthesis of these complexes was the greater kinetic stability of platinum(IV) and recent research has shown that a specific type of platinum(IV) compound shows suitable properties as an anticancer agent. These complexes were characterised by a variety of spectral means (IR, NMR, mass spectroscopy) as well as elemental analysis, solubility determinations, thermal analysis (TGA), ionization studies and finally their anticancer behaviour towards three different cell lines(Hela, MCF 7, Ht29) and in this process they were compared to the behaviour of cisplatin as a reference. A few have shown promising anticancer behaviour.
- Full Text:
- Date Issued: 2009
The effect of temperature and turbidity on spawning chokka squid, loligo reynaudii, in Eastern Cape waters
- Authors: Downey, Nicola Jean
- Date: 2009
- Subjects: Squids -- Effect of temperature on -- South Africa , Squids -- Effect of turbidity on -- South Africa , Squids -- Spawning -- South Africa , Loliginidae -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10719 , http://hdl.handle.net/10948/945 , http://hdl.handle.net/10948/d1012895 , Squids -- Effect of temperature on -- South Africa , Squids -- Effect of turbidity on -- South Africa , Squids -- Spawning -- South Africa , Loliginidae -- South Africa
- Description: Several studies suggest the environment influences chokka squid catches which are mostly based on the successful formation of inshore spawning aggregations. None of the evidence, however, is direct observation. Acoustic telemetry offers a means to determine the response of spawners to changes in the environment and insight into the behaviour of spawning squid. A hexagonal array of VR2 receivers deployed 500 m apart was deemed to be ideal to monitor the movement patterns of squid on the spawning sites. In isothermic conditions, an area up to 1.28 km2 could be monitored as there was an approximate 50 m overlap in individual VR2 receiver range. In thermocline conditions however, “acoustic dead zones” as wide as 350 m may have existed between VR2 receivers, limiting the performance of this configuration. Similarly benthic turbidity events would also decrease detection range and limit performance. A hexagonal array of VR2 receivers was moored in Kromme Bay on and around active spawning aggregations during the squid fishery closed seasons of November 2003, 2004, 2005 and 2006. Squid were caught on jigs and tagged with V9 acoustic pressure telemetry transmitters. A total of 45 animals were tagged. Presence-absence analysis identified three general behaviours: (1) arrival at dawn and departure after dusk, (2) a continuous and uninterrupted presence for a number of days and (3) presence interrupted by frequent but short periods of absence. Overall, the data suggests frequent migrations between spawning aggregations and offshore feeding grounds. The pressure sensor data showed both males and females stayed persistently near the seabed during the day, but at night, this pattern was broken with common activity higher up in the water column. The squid did not remain exclusively in the water column and regularly made excursions to the seabed. CTD and temperature data indicated the intrusion of a cold bottom layer due to upwelling at the monitored spawning sites on a number of occasions. The formation of spawning aggregations appears to be triggered by upwelling events and spawning behaviour, once initiated, disrupted by upwelling events with a rapid onset, possibly due to an inability to adapt physiologically over such a short time period.
- Full Text:
- Date Issued: 2009
- Authors: Downey, Nicola Jean
- Date: 2009
- Subjects: Squids -- Effect of temperature on -- South Africa , Squids -- Effect of turbidity on -- South Africa , Squids -- Spawning -- South Africa , Loliginidae -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10719 , http://hdl.handle.net/10948/945 , http://hdl.handle.net/10948/d1012895 , Squids -- Effect of temperature on -- South Africa , Squids -- Effect of turbidity on -- South Africa , Squids -- Spawning -- South Africa , Loliginidae -- South Africa
- Description: Several studies suggest the environment influences chokka squid catches which are mostly based on the successful formation of inshore spawning aggregations. None of the evidence, however, is direct observation. Acoustic telemetry offers a means to determine the response of spawners to changes in the environment and insight into the behaviour of spawning squid. A hexagonal array of VR2 receivers deployed 500 m apart was deemed to be ideal to monitor the movement patterns of squid on the spawning sites. In isothermic conditions, an area up to 1.28 km2 could be monitored as there was an approximate 50 m overlap in individual VR2 receiver range. In thermocline conditions however, “acoustic dead zones” as wide as 350 m may have existed between VR2 receivers, limiting the performance of this configuration. Similarly benthic turbidity events would also decrease detection range and limit performance. A hexagonal array of VR2 receivers was moored in Kromme Bay on and around active spawning aggregations during the squid fishery closed seasons of November 2003, 2004, 2005 and 2006. Squid were caught on jigs and tagged with V9 acoustic pressure telemetry transmitters. A total of 45 animals were tagged. Presence-absence analysis identified three general behaviours: (1) arrival at dawn and departure after dusk, (2) a continuous and uninterrupted presence for a number of days and (3) presence interrupted by frequent but short periods of absence. Overall, the data suggests frequent migrations between spawning aggregations and offshore feeding grounds. The pressure sensor data showed both males and females stayed persistently near the seabed during the day, but at night, this pattern was broken with common activity higher up in the water column. The squid did not remain exclusively in the water column and regularly made excursions to the seabed. CTD and temperature data indicated the intrusion of a cold bottom layer due to upwelling at the monitored spawning sites on a number of occasions. The formation of spawning aggregations appears to be triggered by upwelling events and spawning behaviour, once initiated, disrupted by upwelling events with a rapid onset, possibly due to an inability to adapt physiologically over such a short time period.
- Full Text:
- Date Issued: 2009
The effect of tulbaghia violacea plant extract on the growth of aspergillus species
- Authors: Belewa, Xoliswa Vuyokazi
- Date: 2009
- Subjects: Plant products , Plant extracts , Traditional medicine
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10315 , http://hdl.handle.net/10948/d1008186 , Plant products , Plant extracts , Traditional medicine
- Description: Traditional medicine has become an important part of healthcare worldwide. It is estimated that about 25 percent of prescribed medicines contain plant products or active compounds derived from plants. In South Africa, traditional medicine forms part of the culture and tradition of most communities. Garlic compounds have been shown to have a variety of antimicrobial properties. Amongst these are antifungal, antibacterial, antiviral and anti protozoal activities. Allicin and its breakdown products have been shown to be the main active compounds which possess these properties. Tulbaghia violacea has been used for the treatment of a variety of illnesses including asthma, fever, oesophageal cancer, constipation and hypertension. This study investigated the antifungal nature of T.violacea on the morphology, spore germination and lipid synthesis of Aspergillus flavus and Aspergillus parasiticus. The results of this study showed that the plant extract inhibited A. flavus growth at a minimal inhibitory concentration of 15mg/ml and was fungicidal at 20mg/ml and above. A. parasiticus was not inhibited at 25mg/ml indicating resistance to the inhibitory component of the plant extract. A measure of metabolic activity using the XTT assay showed reduced metabolic activity in the presence of increasing concentrations of the plant extract. Higher extract concentrations resulted in higher percentage inhibition of fungal growth for both fungal species with up to 98 percent inhibition being observed for the highest extract concentrations for both fungi. Germination was also delayed in the presence of 15mg/ml plant extract concentration by up to 60hr for A. flavus and 48hr for A. parasititcus. The TEM results showed increased thickening of the cell wall with higher extract concentrations. The thickening was greater for A. flavus than for A. parasiticus. Cell wall thickening may be the reason for the delay in germination in both species. Lipid production was reduced in the presence of plant extracts when compared to the control. The plant extracts inhibited triglyceride production at 15mg/ml for both A. flavus and A. parasiticus. The results therefore indicate that T. violacea extracts are antifungal and probably affect germination through interactions with the cell wall. It is possible that the extract affects lipid production in Aspergillus species.
- Full Text:
- Date Issued: 2009
- Authors: Belewa, Xoliswa Vuyokazi
- Date: 2009
- Subjects: Plant products , Plant extracts , Traditional medicine
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10315 , http://hdl.handle.net/10948/d1008186 , Plant products , Plant extracts , Traditional medicine
- Description: Traditional medicine has become an important part of healthcare worldwide. It is estimated that about 25 percent of prescribed medicines contain plant products or active compounds derived from plants. In South Africa, traditional medicine forms part of the culture and tradition of most communities. Garlic compounds have been shown to have a variety of antimicrobial properties. Amongst these are antifungal, antibacterial, antiviral and anti protozoal activities. Allicin and its breakdown products have been shown to be the main active compounds which possess these properties. Tulbaghia violacea has been used for the treatment of a variety of illnesses including asthma, fever, oesophageal cancer, constipation and hypertension. This study investigated the antifungal nature of T.violacea on the morphology, spore germination and lipid synthesis of Aspergillus flavus and Aspergillus parasiticus. The results of this study showed that the plant extract inhibited A. flavus growth at a minimal inhibitory concentration of 15mg/ml and was fungicidal at 20mg/ml and above. A. parasiticus was not inhibited at 25mg/ml indicating resistance to the inhibitory component of the plant extract. A measure of metabolic activity using the XTT assay showed reduced metabolic activity in the presence of increasing concentrations of the plant extract. Higher extract concentrations resulted in higher percentage inhibition of fungal growth for both fungal species with up to 98 percent inhibition being observed for the highest extract concentrations for both fungi. Germination was also delayed in the presence of 15mg/ml plant extract concentration by up to 60hr for A. flavus and 48hr for A. parasititcus. The TEM results showed increased thickening of the cell wall with higher extract concentrations. The thickening was greater for A. flavus than for A. parasiticus. Cell wall thickening may be the reason for the delay in germination in both species. Lipid production was reduced in the presence of plant extracts when compared to the control. The plant extracts inhibited triglyceride production at 15mg/ml for both A. flavus and A. parasiticus. The results therefore indicate that T. violacea extracts are antifungal and probably affect germination through interactions with the cell wall. It is possible that the extract affects lipid production in Aspergillus species.
- Full Text:
- Date Issued: 2009
The effects of a Kenyan antidiabetic plant on insulin homeostasis
- Authors: Suleiman, Khairunisa Yahya
- Date: 2009
- Subjects: Medicinal plants -- Kenya , Insulin resistance
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10326 , http://hdl.handle.net/10948/1055 , Medicinal plants -- Kenya , Insulin resistance
- Description: The metabolic disorder diabetes; is a global epidemic affecting people in developed countries and increasingly in developing countries. In two decades time, 350 million people will be diabetic at the current rate of prevalence. In a preliminary study, insulin resistant rats were treated with Prunus Africana (plant A) for 28 days. Plasma samples obtained from P. africana treated rats had increased insulin levels compared to normal and untreated insulin resistant rats (Karachi, 2009). The treatment of insulin resistant rats with P. africana also showed increased glucose uptake in rat adipose tissue (Karachi, 2009), suggesting that P. africana had anti-diabetic properties. The aim of the study was to investigate the mechanism of the anti-diabetic properties of P africana extract. Increased insulin secretion was confirmed by the increased Cpeptide concentration in plasma samples of rats treated with P. africana. In order to explain the high insulin levels, several hypothesis’ were investigated: (1) P. africana may increase insulin secretion in β cells, hence the effect of P. africana on insulin secretion by INS-1 cells was investigated; (2) P. africana may increase insulin secretion by prolonging the half-life of glucagon like peptide-1 (GLP-1) by decreasing dipeptidyl peptidase IV (DPP IV) activity; the effect of P. africana on DPP IV activity was determined spectrophotometrically, (3) P. africana may increase the half-life of insulin in the plasma by decreasing the activity of insulin degrading enzyme (IDE); the effect of P. africana on IDE in rat muscle and spleen samples was investigated. To explain the increased glucose uptake in adipose tissue observed in the previous study two parameters were investigated: (1) increased GLUT4 expression in P. africana treated rats; the effect of P. africana treatment on the expression of glucose transporter 4 (GLUT4) was determined using real-time polymerase chain reaction (RT-PCR), (2) P. africana may increase glucose utilization; the effect of P. africana on glucose utilization was determined in 3T3-L1 cells. The plant extract did not significantly increase insulin secretion by INS-1 cells in the absence of glucose. P. africana decreased DPP IV activity in rat plasma when compared to the untreated insulin resistant rats and this could be a mechanism by which insulin secretion is increased during plant treatment. P. africana decreased IDE activity (however not significantly) when compared to the untreated insulin resistant The effects of a Kenyan antidiabetic plant on insulin homeostasis KY Suleiman VII rats. P. africana appeared to have no effect on GLUT4 expression. The plant appeared to increase glucose utilization in 3T3-L1 cells in the absence of insulin suggesting that P. africana may have insulin like activity. In summary, this study indicates that P. africana is indirectly involved in inhibiting DDPIV. This in turn can increase the half life of GLP-1, which in turn can enhance the secretion of insulin. P. africana increases glucose utilization although there was no evidence that the GLUT 4 transporter has a higher expression in the plant treated rats. Further studies should be conducted to investigate the expression of GLUT1 under the same conditons.
- Full Text:
- Date Issued: 2009
- Authors: Suleiman, Khairunisa Yahya
- Date: 2009
- Subjects: Medicinal plants -- Kenya , Insulin resistance
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10326 , http://hdl.handle.net/10948/1055 , Medicinal plants -- Kenya , Insulin resistance
- Description: The metabolic disorder diabetes; is a global epidemic affecting people in developed countries and increasingly in developing countries. In two decades time, 350 million people will be diabetic at the current rate of prevalence. In a preliminary study, insulin resistant rats were treated with Prunus Africana (plant A) for 28 days. Plasma samples obtained from P. africana treated rats had increased insulin levels compared to normal and untreated insulin resistant rats (Karachi, 2009). The treatment of insulin resistant rats with P. africana also showed increased glucose uptake in rat adipose tissue (Karachi, 2009), suggesting that P. africana had anti-diabetic properties. The aim of the study was to investigate the mechanism of the anti-diabetic properties of P africana extract. Increased insulin secretion was confirmed by the increased Cpeptide concentration in plasma samples of rats treated with P. africana. In order to explain the high insulin levels, several hypothesis’ were investigated: (1) P. africana may increase insulin secretion in β cells, hence the effect of P. africana on insulin secretion by INS-1 cells was investigated; (2) P. africana may increase insulin secretion by prolonging the half-life of glucagon like peptide-1 (GLP-1) by decreasing dipeptidyl peptidase IV (DPP IV) activity; the effect of P. africana on DPP IV activity was determined spectrophotometrically, (3) P. africana may increase the half-life of insulin in the plasma by decreasing the activity of insulin degrading enzyme (IDE); the effect of P. africana on IDE in rat muscle and spleen samples was investigated. To explain the increased glucose uptake in adipose tissue observed in the previous study two parameters were investigated: (1) increased GLUT4 expression in P. africana treated rats; the effect of P. africana treatment on the expression of glucose transporter 4 (GLUT4) was determined using real-time polymerase chain reaction (RT-PCR), (2) P. africana may increase glucose utilization; the effect of P. africana on glucose utilization was determined in 3T3-L1 cells. The plant extract did not significantly increase insulin secretion by INS-1 cells in the absence of glucose. P. africana decreased DPP IV activity in rat plasma when compared to the untreated insulin resistant rats and this could be a mechanism by which insulin secretion is increased during plant treatment. P. africana decreased IDE activity (however not significantly) when compared to the untreated insulin resistant The effects of a Kenyan antidiabetic plant on insulin homeostasis KY Suleiman VII rats. P. africana appeared to have no effect on GLUT4 expression. The plant appeared to increase glucose utilization in 3T3-L1 cells in the absence of insulin suggesting that P. africana may have insulin like activity. In summary, this study indicates that P. africana is indirectly involved in inhibiting DDPIV. This in turn can increase the half life of GLP-1, which in turn can enhance the secretion of insulin. P. africana increases glucose utilization although there was no evidence that the GLUT 4 transporter has a higher expression in the plant treated rats. Further studies should be conducted to investigate the expression of GLUT1 under the same conditons.
- Full Text:
- Date Issued: 2009
The integration of GIS technology into demographic and quality of life surveying of informal settlements : Nelson Mandela Bay, South Africa
- Authors: Van Niekerk, Susan
- Date: 2009
- Subjects: Demographic surveys -- South Africa -- Port Elizabeth , Geographic information systems -- Social aspects -- South Africa -- Port Elizabeth , Quality of life Statistics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10659 , http://hdl.handle.net/10948/881 , http://hdl.handle.net/10948/d1012888 , Demographic surveys -- South Africa -- Port Elizabeth , Geographic information systems -- Social aspects -- South Africa -- Port Elizabeth , Quality of life Statistics
- Description: A number of mostly informal areas in Nelson Mandela Bay have experienced rapid expansion over the past decade or so. Census data available for these areas is outdated and does not provide enough information for local authorities to accurately plan for tasks such as service delivery management and resource allocation. In this dissertation, a GIS based demographic and Quality of Life study of informal settlements and previously disadvantaged areas within Nelson Mandela Bay is undertaken to address this issue. The study aims to integrate GIS technology into a demographic and Quality of Life survey to significantly improve the collection, analysis, interpretation, display and management of survey data and to provide the accurate and necessary updates required between census collections. Data relating to informal settlements were captured from aerial photographs and satellite imagery and demographic and Quality of Life data were collected from field surveys. The results demonstrated that the use of GIS technology provided more accurate information for demographic variables, including the number of dwellings, dwelling type, size of the population and population dynamics. A specific demographic trend observed through spatial analysis included the identification of backyard shacks predating formal structures in settlements. The analysis and representation of the Quality of Life field survey data in GIS demonstrated how residents' perceptions of problems and issues in their neighbourhoods are better interpreted, understood and managed when analyzed within a spatial context. This research concluded that GIS based demographic and QOL studies are vital for providing accurate social and spatial information for municipalities, particularly in urban environments of developing countries, and for providing the necessary updates to censuses occurring every ten years.
- Full Text:
- Date Issued: 2009
- Authors: Van Niekerk, Susan
- Date: 2009
- Subjects: Demographic surveys -- South Africa -- Port Elizabeth , Geographic information systems -- Social aspects -- South Africa -- Port Elizabeth , Quality of life Statistics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10659 , http://hdl.handle.net/10948/881 , http://hdl.handle.net/10948/d1012888 , Demographic surveys -- South Africa -- Port Elizabeth , Geographic information systems -- Social aspects -- South Africa -- Port Elizabeth , Quality of life Statistics
- Description: A number of mostly informal areas in Nelson Mandela Bay have experienced rapid expansion over the past decade or so. Census data available for these areas is outdated and does not provide enough information for local authorities to accurately plan for tasks such as service delivery management and resource allocation. In this dissertation, a GIS based demographic and Quality of Life study of informal settlements and previously disadvantaged areas within Nelson Mandela Bay is undertaken to address this issue. The study aims to integrate GIS technology into a demographic and Quality of Life survey to significantly improve the collection, analysis, interpretation, display and management of survey data and to provide the accurate and necessary updates required between census collections. Data relating to informal settlements were captured from aerial photographs and satellite imagery and demographic and Quality of Life data were collected from field surveys. The results demonstrated that the use of GIS technology provided more accurate information for demographic variables, including the number of dwellings, dwelling type, size of the population and population dynamics. A specific demographic trend observed through spatial analysis included the identification of backyard shacks predating formal structures in settlements. The analysis and representation of the Quality of Life field survey data in GIS demonstrated how residents' perceptions of problems and issues in their neighbourhoods are better interpreted, understood and managed when analyzed within a spatial context. This research concluded that GIS based demographic and QOL studies are vital for providing accurate social and spatial information for municipalities, particularly in urban environments of developing countries, and for providing the necessary updates to censuses occurring every ten years.
- Full Text:
- Date Issued: 2009
The kinetics and associated reactions of ruthenium(VIII)
- Authors: Van Aswegen, Werner
- Date: 2009
- Subjects: Ruthenium , Ruthenium compounds , Alcohols
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10392 , http://hdl.handle.net/10948/1130 , http://hdl.handle.net/10948/d1008611 , Ruthenium , Ruthenium compounds , Alcohols
- Description: This study investigated the reduction reaction of ruthenium tetroxide by various aliphatic alcohols in acidic medium. UV-Vis spectroscopy still plays an essential role in the analysis and study of volatile ruthenium tetroxide and was used in this study to collect kinetic data. This data was analyzed using graphical and computational methods, such as Mauser diagrams and kinetic simulation software. From the results obtained it is proposed that the reaction occurs by the following two-step reaction model: Ru(VIII) k1 Ru(VI) Ru(VI) k2 k-2 Ru(III) Molar extinction coefficients and conditional rate constants were calculated using kinetic simulating software and a hydride transfer mechanism was proposed. The temperature dependence of this reduction reaction was also investigated and thermodynamic parameters calculated. Ruthenium concentrations were determined using a method employing UV-Vis spectroscopy. The method proved to be a reliable, sensitive and simple technique.
- Full Text:
- Date Issued: 2009
- Authors: Van Aswegen, Werner
- Date: 2009
- Subjects: Ruthenium , Ruthenium compounds , Alcohols
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10392 , http://hdl.handle.net/10948/1130 , http://hdl.handle.net/10948/d1008611 , Ruthenium , Ruthenium compounds , Alcohols
- Description: This study investigated the reduction reaction of ruthenium tetroxide by various aliphatic alcohols in acidic medium. UV-Vis spectroscopy still plays an essential role in the analysis and study of volatile ruthenium tetroxide and was used in this study to collect kinetic data. This data was analyzed using graphical and computational methods, such as Mauser diagrams and kinetic simulation software. From the results obtained it is proposed that the reaction occurs by the following two-step reaction model: Ru(VIII) k1 Ru(VI) Ru(VI) k2 k-2 Ru(III) Molar extinction coefficients and conditional rate constants were calculated using kinetic simulating software and a hydride transfer mechanism was proposed. The temperature dependence of this reduction reaction was also investigated and thermodynamic parameters calculated. Ruthenium concentrations were determined using a method employing UV-Vis spectroscopy. The method proved to be a reliable, sensitive and simple technique.
- Full Text:
- Date Issued: 2009
The reactions of osmium (VIII) in hydroxide medium
- Authors: Geswindt, Theodore Earl
- Date: 2009
- Subjects: Osmium , Spectrophotometry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10395 , http://hdl.handle.net/10948/960 , Osmium , Spectrophotometry
- Description: Spectrophotometric techniques were used to elucidate the discrepancies surrounding the reduction of osmium tetroxide by several primary alcohols in a hydroxide matrix. In contrast to the documented literature, this reaction was observed to occur in two consecutive reaction steps. Geometrical and computational analysis of kinetic data revealed that the reaction proceeds by the following reaction model: Os(VIII) + RCH2OH Os(VI) + RCHO Os(VIII) + Os(VI) Os2(VII) k1 k+2 k-2 The conditional rate constants and molar extinction coefficients were calculated using custom written software. A hydride transfer mechanism, coupled with the synchronous removal of the hydroxyl proton of the alcohol, was postulated. The complexation between osmium(VIII) and osmium(VI) was investigated. Mole ratio titrations and mole fraction plots show that at pH 14.3 a 1:1 complexation occurs between osmium(VIII) and osmium(VI). The equilibrium constants and molar extinction coefficients calculated by these methods were found to be consistent with the parameters obtained from the reduction of osmium tetroxide by primary alcohols at pH 14.3. The formation of a mixed oxidation state dimeric osmium complex (denoted Os2(VII)) has been proposed. Key words: Spectrophotometric techniques, osmium tetroxide, osmium(VIII), primary alcohols, osmium(VI).
- Full Text:
- Date Issued: 2009
- Authors: Geswindt, Theodore Earl
- Date: 2009
- Subjects: Osmium , Spectrophotometry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10395 , http://hdl.handle.net/10948/960 , Osmium , Spectrophotometry
- Description: Spectrophotometric techniques were used to elucidate the discrepancies surrounding the reduction of osmium tetroxide by several primary alcohols in a hydroxide matrix. In contrast to the documented literature, this reaction was observed to occur in two consecutive reaction steps. Geometrical and computational analysis of kinetic data revealed that the reaction proceeds by the following reaction model: Os(VIII) + RCH2OH Os(VI) + RCHO Os(VIII) + Os(VI) Os2(VII) k1 k+2 k-2 The conditional rate constants and molar extinction coefficients were calculated using custom written software. A hydride transfer mechanism, coupled with the synchronous removal of the hydroxyl proton of the alcohol, was postulated. The complexation between osmium(VIII) and osmium(VI) was investigated. Mole ratio titrations and mole fraction plots show that at pH 14.3 a 1:1 complexation occurs between osmium(VIII) and osmium(VI). The equilibrium constants and molar extinction coefficients calculated by these methods were found to be consistent with the parameters obtained from the reduction of osmium tetroxide by primary alcohols at pH 14.3. The formation of a mixed oxidation state dimeric osmium complex (denoted Os2(VII)) has been proposed. Key words: Spectrophotometric techniques, osmium tetroxide, osmium(VIII), primary alcohols, osmium(VI).
- Full Text:
- Date Issued: 2009
The reactions of ruthenium (ii) polypyridyl complexes
- Authors: Zheng, Sipeng
- Date: 2009
- Subjects: Ruthenium , Ruthenium compounds , Chemical reactions
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10374 , http://hdl.handle.net/10948/1089 , Ruthenium , Ruthenium compounds , Chemical reactions
- Description: Ruthenium (II) polypyridine complexes in general have been extensively studied because of their unique redox and photochemical properties. A typical example of such complexes is tris(2,2’-bipyridyl) ruthenium (II). In this study, this complex was synthesized and then characterized using electronic spectroscopy and cyclic voltammetry. It was also shown that the ruthenium concentration could be accurately determined using ICP-MS. It was found that the complex is very stable in various chemical environments. It was observed from spectrophotometric investigations that persulphate and lead dioxide easily oxidize Ru(bpy)3 2+ to Ru(bpy)3 3+ in the presence of heat and H2SO4, respectively. It was also observed that the oxidation between Ru(bpy)3 2+ and cerium (IV) occurred at approximately 3:2 [Ce(IV)]/[Ru(II)] mole ratio. The resultant Ru(bpy)3 3+ solution was unstable in the presence of light and recovery of Ru(bpy)3 2+ occurred gradually. The regeneration of Ru(bpy)3 2+ from Ru(bpy)3 3+ was found to be a multistep process, which appears to involve the formation of an intermediate species. The following reaction model was found to best explain the kinetic data obtained: Ru(bpy)3 2+ + Ce(IV) → Ru(bpy)3 3+ Ru(bpy)3 3+ → Ru(bpy)3 2+ Ru(bpy)3 3+ → Ru* intermediate Ru* intermediate → Ru(bpy)3 2+ Theoretical rate constants were also calculated for the same process under the experimental conditions. The comparison between the experimental and theoretical results gave good agreement. In addition, the factors that influence the rate of the regeneration of Ru(bpy)3 2+ from Ru(bpy)3 3+ were also discussed.
- Full Text:
- Date Issued: 2009
- Authors: Zheng, Sipeng
- Date: 2009
- Subjects: Ruthenium , Ruthenium compounds , Chemical reactions
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10374 , http://hdl.handle.net/10948/1089 , Ruthenium , Ruthenium compounds , Chemical reactions
- Description: Ruthenium (II) polypyridine complexes in general have been extensively studied because of their unique redox and photochemical properties. A typical example of such complexes is tris(2,2’-bipyridyl) ruthenium (II). In this study, this complex was synthesized and then characterized using electronic spectroscopy and cyclic voltammetry. It was also shown that the ruthenium concentration could be accurately determined using ICP-MS. It was found that the complex is very stable in various chemical environments. It was observed from spectrophotometric investigations that persulphate and lead dioxide easily oxidize Ru(bpy)3 2+ to Ru(bpy)3 3+ in the presence of heat and H2SO4, respectively. It was also observed that the oxidation between Ru(bpy)3 2+ and cerium (IV) occurred at approximately 3:2 [Ce(IV)]/[Ru(II)] mole ratio. The resultant Ru(bpy)3 3+ solution was unstable in the presence of light and recovery of Ru(bpy)3 2+ occurred gradually. The regeneration of Ru(bpy)3 2+ from Ru(bpy)3 3+ was found to be a multistep process, which appears to involve the formation of an intermediate species. The following reaction model was found to best explain the kinetic data obtained: Ru(bpy)3 2+ + Ce(IV) → Ru(bpy)3 3+ Ru(bpy)3 3+ → Ru(bpy)3 2+ Ru(bpy)3 3+ → Ru* intermediate Ru* intermediate → Ru(bpy)3 2+ Theoretical rate constants were also calculated for the same process under the experimental conditions. The comparison between the experimental and theoretical results gave good agreement. In addition, the factors that influence the rate of the regeneration of Ru(bpy)3 2+ from Ru(bpy)3 3+ were also discussed.
- Full Text:
- Date Issued: 2009