Beauty from Ashes:short term postfire regeneration of dune fynbos -thicket vegetation in the South Eastern Cape floristic region
- Authors: Gcina, Sinenjongo
- Date: 2022-12
- Subjects: Fynbos ecology – Nelson Mandela University Campus Nature Reserve , Forest fires -- Prevention and control
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/59666 , vital:62319
- Description: Aim This study aims to provide an understanding and a description of the short-term postfire regeneration and ecology of the fynbos-thicket vegetation on a coastal dune system in the southeastern Cape Floristic Region. Another aim is to assess the recovery of the vegetation community by assessing the growth forms and the disturbance response across a range of species from thicket and fynbos communities and to provide a belowground bud bank classification for each of these species in the coastal dune systems. Location The study site was the Mandela University Reserve and the Noordhoek dune fields, situated in Gqeberha, Eastern Cape, which is part of the south-eastern Cape Floristic Region. The study site hosts thicket-fynbos mosaic vegetation type that occurs in a Mediterranean-Climate Ecosystem (MCE). Methods Firstly, field observations and photographs of plant species were taken weekly to assess and identify the species that were emerging and persisting in the dune system in the first 12 months postfire. Phenological events of the species that emerged (e.g., flowering, fruiting, leaf growth, leaf yellowing, and leaf abscission) were also observed and reported on. Secondly, an excavation of 21 species (e.g., Jamesbrittenia microphylla, Euclea racemosa, Olea exasperata, Searsia laevigata) was conducted to classify the species into their belowground bud bank types. Results There was a rapid emergence of resprouters (facultative resprouters and obligate resprouters) in the first 12 months postfire. This was followed by their growth; primarily occurring after the rainfall events. The dominant resprouting species (facultative resprouters and obligate resprouters) entered the system two weeks after the fire. There was a significant difference in the time to the first emergence of the different regeneration groups postfire (P < 0.001): on average, obligate sprouters (OS) appeared 1 month after fire – two months earlier than facultative sprouters (FS) and four months earlier than non-sprouters (NS). There was no statistical evidence to suggest that the FS and non-sprouters NS emerged at different times postfire; however, most NS species were observed in the system 5 months after fire. 4 Exceptions were the NS species Pelargonium grossularoides and Mesembryanthemum aitonis, both annuals that emerged 1 month after fire. A wide range of OS species that appeared earlier in the system (e.g., Euclea racemosa, Olea exasperata, Searsia laevigata, and Lauridia tetragona) exhibit underground lateral growth with belowground bud banks (BBBs) from which they recover after disturbance. In total, six BBB types were recorded in this study, namely: bud-bearing root, rhizome, rhizophore, woody rhizome, stem tuber, and corms. The bud-bearing root from woody species was the dominant BBB in this system. Main conclusion The return of species that occurs in the first year after fire occurs rapidly in the first 2 months as resprouting species (primarily OS) appear in the system. Following this, the rate of return of species decreases as reseeding species (primarily NS) gradually reestablish and occupy the gaps in the dune fynbos-thicket vegetation. This study has shown that plant species in this ecosystem are adapted to fire disturbance as their populations are able to reestablish through various regeneration strategies, including resprouting from different types of BBB. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-12
- Authors: Gcina, Sinenjongo
- Date: 2022-12
- Subjects: Fynbos ecology – Nelson Mandela University Campus Nature Reserve , Forest fires -- Prevention and control
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/59666 , vital:62319
- Description: Aim This study aims to provide an understanding and a description of the short-term postfire regeneration and ecology of the fynbos-thicket vegetation on a coastal dune system in the southeastern Cape Floristic Region. Another aim is to assess the recovery of the vegetation community by assessing the growth forms and the disturbance response across a range of species from thicket and fynbos communities and to provide a belowground bud bank classification for each of these species in the coastal dune systems. Location The study site was the Mandela University Reserve and the Noordhoek dune fields, situated in Gqeberha, Eastern Cape, which is part of the south-eastern Cape Floristic Region. The study site hosts thicket-fynbos mosaic vegetation type that occurs in a Mediterranean-Climate Ecosystem (MCE). Methods Firstly, field observations and photographs of plant species were taken weekly to assess and identify the species that were emerging and persisting in the dune system in the first 12 months postfire. Phenological events of the species that emerged (e.g., flowering, fruiting, leaf growth, leaf yellowing, and leaf abscission) were also observed and reported on. Secondly, an excavation of 21 species (e.g., Jamesbrittenia microphylla, Euclea racemosa, Olea exasperata, Searsia laevigata) was conducted to classify the species into their belowground bud bank types. Results There was a rapid emergence of resprouters (facultative resprouters and obligate resprouters) in the first 12 months postfire. This was followed by their growth; primarily occurring after the rainfall events. The dominant resprouting species (facultative resprouters and obligate resprouters) entered the system two weeks after the fire. There was a significant difference in the time to the first emergence of the different regeneration groups postfire (P < 0.001): on average, obligate sprouters (OS) appeared 1 month after fire – two months earlier than facultative sprouters (FS) and four months earlier than non-sprouters (NS). There was no statistical evidence to suggest that the FS and non-sprouters NS emerged at different times postfire; however, most NS species were observed in the system 5 months after fire. 4 Exceptions were the NS species Pelargonium grossularoides and Mesembryanthemum aitonis, both annuals that emerged 1 month after fire. A wide range of OS species that appeared earlier in the system (e.g., Euclea racemosa, Olea exasperata, Searsia laevigata, and Lauridia tetragona) exhibit underground lateral growth with belowground bud banks (BBBs) from which they recover after disturbance. In total, six BBB types were recorded in this study, namely: bud-bearing root, rhizome, rhizophore, woody rhizome, stem tuber, and corms. The bud-bearing root from woody species was the dominant BBB in this system. Main conclusion The return of species that occurs in the first year after fire occurs rapidly in the first 2 months as resprouting species (primarily OS) appear in the system. Following this, the rate of return of species decreases as reseeding species (primarily NS) gradually reestablish and occupy the gaps in the dune fynbos-thicket vegetation. This study has shown that plant species in this ecosystem are adapted to fire disturbance as their populations are able to reestablish through various regeneration strategies, including resprouting from different types of BBB. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-12
Isocyanide complexes of rhenium
- Authors: Schoultz, Xandri
- Date: 2013
- Subjects: Isocyanides , Rhenium , Complex compounds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10360 , http://hdl.handle.net/10948/d1021069
- Description: This study investigates the synthesis of rhenium(III)-isocyanide complexes with potentially bidentate ligands, as well as the reactivity of isocyanide ligands toward rhenium(I) and (V). The crystal structures of all the complexes have been determined by X-ray diffraction methods. The coordination behaviour of trans-[ReIIICl3(t-BuNC)(PPh3)2] with aniline and its derivatives were investigated. The isocyanide-containing rhenium(V) complexes [ReCl3(t-BuNC)(L)(PPh3)] were isolated, with the ligands H2L (aniline, o-phenylenediamine and anthranilic acid). In all these complexes the dianionic ligands L are coordinated monodentately as the imide. However, with 2-aminophenol the complexes [ReVCl2(t-BuNC)(L)(PPh3)2](ReO4) and [ReIIICl2(t-BuNC)(ibq)(PPh3)2] (ibq- = 2-iminobenzoquinonate) were identified as the products. [ReCl2(t-BuNC)(L)(PPh3)2](ReO4) is the product of a disproportionation reaction from Re(III) to Re(VII) and Re(V). All the above complexes show a distorted octahedral geometry around the rhenium. The products of the reaction of the Re(I) complex [Re(CO)5Cl] with isocyanides (tert-butyl- and cyclohexylisocyanide) are reported. Rhenium(I) tricarbonyl complexes of the form [Re(CO)3(CNR)2Cl] were isolated and they were characterized structurally and spectroscopically. The tricarbonyls are coordinated in the typical facial-fashion, whereas the isocyanides are coordinated cis to each other. The reaction of [Re(CO)3(t-BuNC)2Cl] with H2O led to the formation of the rhenium(I) complex [Re(CO)3(t-BuNC)2(OH2)] in which the aquo ligand can readily be substituted by a more complex ligand. The reaction of the rhenium(V) complexes cis-[ReO2I(PPh3)2] and mer-[ReOCl3(SMe2)(OPPh3)] with isocyanides were studied. The seven-coordinate trigonal prismatic, square faced monocapped rhenium(III) complex [ReI3(t-BuNC)3(PPh3)] was surprisingly isolated upon reacting cis-[ReO2I(PPh3)2] with tert-butyl isocyanide. The dimeric complex (μ-O)[ReOCl2(CNC6H11)2]2 was obtained from the reaction of mer-[ReOCl3(SMe2)(OPPh3)] with cyclohexyl isocyanide.
- Full Text:
- Date Issued: 2013
- Authors: Schoultz, Xandri
- Date: 2013
- Subjects: Isocyanides , Rhenium , Complex compounds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10360 , http://hdl.handle.net/10948/d1021069
- Description: This study investigates the synthesis of rhenium(III)-isocyanide complexes with potentially bidentate ligands, as well as the reactivity of isocyanide ligands toward rhenium(I) and (V). The crystal structures of all the complexes have been determined by X-ray diffraction methods. The coordination behaviour of trans-[ReIIICl3(t-BuNC)(PPh3)2] with aniline and its derivatives were investigated. The isocyanide-containing rhenium(V) complexes [ReCl3(t-BuNC)(L)(PPh3)] were isolated, with the ligands H2L (aniline, o-phenylenediamine and anthranilic acid). In all these complexes the dianionic ligands L are coordinated monodentately as the imide. However, with 2-aminophenol the complexes [ReVCl2(t-BuNC)(L)(PPh3)2](ReO4) and [ReIIICl2(t-BuNC)(ibq)(PPh3)2] (ibq- = 2-iminobenzoquinonate) were identified as the products. [ReCl2(t-BuNC)(L)(PPh3)2](ReO4) is the product of a disproportionation reaction from Re(III) to Re(VII) and Re(V). All the above complexes show a distorted octahedral geometry around the rhenium. The products of the reaction of the Re(I) complex [Re(CO)5Cl] with isocyanides (tert-butyl- and cyclohexylisocyanide) are reported. Rhenium(I) tricarbonyl complexes of the form [Re(CO)3(CNR)2Cl] were isolated and they were characterized structurally and spectroscopically. The tricarbonyls are coordinated in the typical facial-fashion, whereas the isocyanides are coordinated cis to each other. The reaction of [Re(CO)3(t-BuNC)2Cl] with H2O led to the formation of the rhenium(I) complex [Re(CO)3(t-BuNC)2(OH2)] in which the aquo ligand can readily be substituted by a more complex ligand. The reaction of the rhenium(V) complexes cis-[ReO2I(PPh3)2] and mer-[ReOCl3(SMe2)(OPPh3)] with isocyanides were studied. The seven-coordinate trigonal prismatic, square faced monocapped rhenium(III) complex [ReI3(t-BuNC)3(PPh3)] was surprisingly isolated upon reacting cis-[ReO2I(PPh3)2] with tert-butyl isocyanide. The dimeric complex (μ-O)[ReOCl2(CNC6H11)2]2 was obtained from the reaction of mer-[ReOCl3(SMe2)(OPPh3)] with cyclohexyl isocyanide.
- Full Text:
- Date Issued: 2013
The development and evaluation of a new manufacturing process for β-sitosterol-D glucoside
- Mtyopo, Mthetheleli Bethwell
- Authors: Mtyopo, Mthetheleli Bethwell
- Date: 2016
- Subjects: Pharmaceutical chemistry Chemistry, Organic
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: http://hdl.handle.net/10948/45920 , vital:39320
- Description: The existing production sequence of β-sitosterol-D-glucoside, a glucoside used in an “over-the-counter” (OTC) preparation under the brand name of Moducare® comprises of three process steps with an overall yield of less than 20%. The low yield is partly due to the instability of intermediates at reaction temperatures > 0oC, and partly due to the thermodynamic equilibrium between two stereoisomers. An economically alternative process was developed, evaluated and scaled-up in a 2l reactor. The project was initiated with a specific limitation in terms of the starting material that comprised a mixture of plant sterols, which necessitated a study of the isolation and purification of the desired product from a rather complex reaction mixture. The use of silver as halide acceptor for the Koenigs-Knorr synthesis did not give statistically significant different results from the same approach but using cadmium as halide acceptor instead. However, using the direct O-glucosylation approach not only gave statistically significant higher results, but also resulted in a much more convenient procedure. Under optimum conditions, a yield of approximately 83% (isolated) of 2,3,4,6- tetra-О-acetyl-β-sitosterol-D-glucoside could be achieved, which was substantially higher than that achieved with the traditional Koenigs-Knorr methodology and above reported yields in the literature (60-80%) for direct glycosylation. Separation of 2,3,4,6-tetra-О-acetyl-β-sitosterol-D-glucoside (BSSGT) from a reaction mixture that contains 2,3,4,6-tetra-О-acetyl-campesterol-D-glucoside (CSGT), 2,3,4,6-tetra-О-acetyl campestanol-glucoside (CSSGT), and 2,3,4,6-tetra-О-acetyl-sitostanol-Dglucoside (SSGT) was investigated using column chromatography. When using silica gel particles, very good separation efficiency and product recovery could be achieved using hexane/ethyl hexane as eluent. The isolated 2,3,4,6-tetra-О-acetyl-β-sitosterol-Dglucoside was easily hydrolysed to β-sitosterol-D-glucoside in high yields (79%) using methanolic KOH. The process for the production of β-sitosterol-D-glucoside was scaled-up from the laboratory bench scale (250 cm3) to a laboratory scale of 2 l using the direct Oglycosylation method. The overall yields of the scaled reaction for β-sitosterol-D-glucoside was slightly above the literature reported values (59%, 8/92) for the KnoenigsKnorr synthesis and compares well above (62%, 0/100) the current production process (less than 20% yields). When using catalogue prices, the material costs (without recycling) for the direct Oglucosylation route is approximately 57% less for the synthesis of 1kg of β-sitosterol-Dglucoside compared to the Koenigs-Knorr route. Given further savings for recycling, the direct O-glucosylation route provides an attractive alternative route for the synthesis ofthe target compound.
- Full Text:
- Date Issued: 2016
- Authors: Mtyopo, Mthetheleli Bethwell
- Date: 2016
- Subjects: Pharmaceutical chemistry Chemistry, Organic
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: http://hdl.handle.net/10948/45920 , vital:39320
- Description: The existing production sequence of β-sitosterol-D-glucoside, a glucoside used in an “over-the-counter” (OTC) preparation under the brand name of Moducare® comprises of three process steps with an overall yield of less than 20%. The low yield is partly due to the instability of intermediates at reaction temperatures > 0oC, and partly due to the thermodynamic equilibrium between two stereoisomers. An economically alternative process was developed, evaluated and scaled-up in a 2l reactor. The project was initiated with a specific limitation in terms of the starting material that comprised a mixture of plant sterols, which necessitated a study of the isolation and purification of the desired product from a rather complex reaction mixture. The use of silver as halide acceptor for the Koenigs-Knorr synthesis did not give statistically significant different results from the same approach but using cadmium as halide acceptor instead. However, using the direct O-glucosylation approach not only gave statistically significant higher results, but also resulted in a much more convenient procedure. Under optimum conditions, a yield of approximately 83% (isolated) of 2,3,4,6- tetra-О-acetyl-β-sitosterol-D-glucoside could be achieved, which was substantially higher than that achieved with the traditional Koenigs-Knorr methodology and above reported yields in the literature (60-80%) for direct glycosylation. Separation of 2,3,4,6-tetra-О-acetyl-β-sitosterol-D-glucoside (BSSGT) from a reaction mixture that contains 2,3,4,6-tetra-О-acetyl-campesterol-D-glucoside (CSGT), 2,3,4,6-tetra-О-acetyl campestanol-glucoside (CSSGT), and 2,3,4,6-tetra-О-acetyl-sitostanol-Dglucoside (SSGT) was investigated using column chromatography. When using silica gel particles, very good separation efficiency and product recovery could be achieved using hexane/ethyl hexane as eluent. The isolated 2,3,4,6-tetra-О-acetyl-β-sitosterol-Dglucoside was easily hydrolysed to β-sitosterol-D-glucoside in high yields (79%) using methanolic KOH. The process for the production of β-sitosterol-D-glucoside was scaled-up from the laboratory bench scale (250 cm3) to a laboratory scale of 2 l using the direct Oglycosylation method. The overall yields of the scaled reaction for β-sitosterol-D-glucoside was slightly above the literature reported values (59%, 8/92) for the KnoenigsKnorr synthesis and compares well above (62%, 0/100) the current production process (less than 20% yields). When using catalogue prices, the material costs (without recycling) for the direct Oglucosylation route is approximately 57% less for the synthesis of 1kg of β-sitosterol-Dglucoside compared to the Koenigs-Knorr route. Given further savings for recycling, the direct O-glucosylation route provides an attractive alternative route for the synthesis ofthe target compound.
- Full Text:
- Date Issued: 2016
A chemo-enzymatic process for the production of beta-thymidine, a key intermediate in antiretrovirol manufacture
- Gordon, Gregory Ernest Robert
- Authors: Gordon, Gregory Ernest Robert
- Date: 2010
- Subjects: HIV infections -- Treatment -- South Africa , HIV infections -- South Africa -- Prevention , Antiretroviral agents
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10423 , http://hdl.handle.net/10948/d1016217
- Description: The socio-economic impact of HIV/AIDS on South Africa has resulted in lower gross domestic product, loss of skills in key sectors such as education, and increased health-care costs in providing access to treatment. Currently active pharmaceutical ingredients (API’s) such as stavudine (d4T) and azidothymidine (AZT) are imported from India and China, while formulation is conducted locally. A strategy was initiated between CSIR Biosciences and LIFElab under the auspices of Arvir Technologies to investigate the feasibility of local antiretroviral manufacture (d4T and AZT) or the manufacture of a key intermediate such as β- thymidine (dT). Several advantages associated with successful implementation of this strategy include ensuring a local supply of API’s, thus reducing reliance on procurement from foreign sources and reducing the effect of foreign exchange rate fluctuations on providing cost effective access to treatment. A local supply source would also reduce the imports and thus aid the balance of payments deficit, and in addition to this, provide stimulus in the local pharmaceutical manufacturing industry (which has been in decline for several decades), resulting in increased skills and employment opportunities. This thesis describes the development of a superior chemo-enzymatic process for the production of β-thymidine (72 percent yield, prior to isolation), a key intermediate in the preparation of anti-retrovirals. Alternative processes based purely on chemical or bioprocess transformations to prepare either 5-methyluridine (5-MU) or dT suffer from several disadvantages: lengthy transformations due to protection/deprotection strategies, low selectivties and product yields (30 percent in the chemical process) and isolation of the product from dilute process streams requiring the use of large uneconomical reactors (bioprocesss). This contributes significantly to the cost of d4T and AZT manufacture. Our novel chemoenzymatic process comprises of a biocatalytic reaction for the production of 5-MU, with subsequent chemical transformation into dT (3 steps) negating and circumventing the limitations of the chemical or bioprocess routes. During the course of this project development, the β-thymidine selling price declined from 175 $/kg (2005) to 100 $/kg (2008). However, the process described in this work is still competitive based on the current β- thymidine selling price of 100 $/kg. The process economics show that with further optimization and increasing the isolated dT yield from 70 percent to 90 percent, the variable cost decreases from 136 $/kg to 110 $/kg. The increase in isolated yield is highly probable, based on solubility data of β-thymidine. The decrease in β-thymidine selling price and technological improvement in dT manufacture should translate into lower API manufacture costs and more cost effective access to treatment. Our novel biocatalytic process producing 5-MU uses a coupled enzyme system employing PNP, Purine Nucleoside Phosphorylase and PyNP, Pyrimidine Nucleoside Phosphorylase. The overall transglycosylation reaction may be decoupled into the phosphorolysis reaction (PNP) and synthesis reaction (PyNP). During the phosphorolysis reaction, guanosine is converted into guanine and ribose-1-phosphate (R-1-P) in the presence of PNP enzyme. The reaction intermediate R-1-P is then coupled to thymine in the presence of PyNP enzyme during the synthesis reaction, producing 5-MU. The process was scaled up from lab-scale to bench-scale (10 - 20 L) and demonstrated to be robust and reproducible. This is evident from the average guanosine conversion (94.7 percent ± 2.03) and 5-MU yield (88.2 percent ± 6.21) and mole balance (104 percent ± 7.61) which were obtained at bench-scale (3 replicates, 10 L). The reaction was carried out at reactor productivities of between 7 – 11 g.L-1.h-1. The integration of the biocatalytic process and chemical processes was successfully carried out, showing that 5-MU produced using our novel biocatalytic process behaved similarly to commercially available 5- MU (ex. Dayang Chemicals, China). A PCT patent application (Ref. No. P44422PC01) on this chemo-enzymatic process has been filed and currently public private partnerships are being explored through Arvir Technologies to evaluate and validate this technology at one ton scale.
- Full Text:
- Date Issued: 2010
- Authors: Gordon, Gregory Ernest Robert
- Date: 2010
- Subjects: HIV infections -- Treatment -- South Africa , HIV infections -- South Africa -- Prevention , Antiretroviral agents
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10423 , http://hdl.handle.net/10948/d1016217
- Description: The socio-economic impact of HIV/AIDS on South Africa has resulted in lower gross domestic product, loss of skills in key sectors such as education, and increased health-care costs in providing access to treatment. Currently active pharmaceutical ingredients (API’s) such as stavudine (d4T) and azidothymidine (AZT) are imported from India and China, while formulation is conducted locally. A strategy was initiated between CSIR Biosciences and LIFElab under the auspices of Arvir Technologies to investigate the feasibility of local antiretroviral manufacture (d4T and AZT) or the manufacture of a key intermediate such as β- thymidine (dT). Several advantages associated with successful implementation of this strategy include ensuring a local supply of API’s, thus reducing reliance on procurement from foreign sources and reducing the effect of foreign exchange rate fluctuations on providing cost effective access to treatment. A local supply source would also reduce the imports and thus aid the balance of payments deficit, and in addition to this, provide stimulus in the local pharmaceutical manufacturing industry (which has been in decline for several decades), resulting in increased skills and employment opportunities. This thesis describes the development of a superior chemo-enzymatic process for the production of β-thymidine (72 percent yield, prior to isolation), a key intermediate in the preparation of anti-retrovirals. Alternative processes based purely on chemical or bioprocess transformations to prepare either 5-methyluridine (5-MU) or dT suffer from several disadvantages: lengthy transformations due to protection/deprotection strategies, low selectivties and product yields (30 percent in the chemical process) and isolation of the product from dilute process streams requiring the use of large uneconomical reactors (bioprocesss). This contributes significantly to the cost of d4T and AZT manufacture. Our novel chemoenzymatic process comprises of a biocatalytic reaction for the production of 5-MU, with subsequent chemical transformation into dT (3 steps) negating and circumventing the limitations of the chemical or bioprocess routes. During the course of this project development, the β-thymidine selling price declined from 175 $/kg (2005) to 100 $/kg (2008). However, the process described in this work is still competitive based on the current β- thymidine selling price of 100 $/kg. The process economics show that with further optimization and increasing the isolated dT yield from 70 percent to 90 percent, the variable cost decreases from 136 $/kg to 110 $/kg. The increase in isolated yield is highly probable, based on solubility data of β-thymidine. The decrease in β-thymidine selling price and technological improvement in dT manufacture should translate into lower API manufacture costs and more cost effective access to treatment. Our novel biocatalytic process producing 5-MU uses a coupled enzyme system employing PNP, Purine Nucleoside Phosphorylase and PyNP, Pyrimidine Nucleoside Phosphorylase. The overall transglycosylation reaction may be decoupled into the phosphorolysis reaction (PNP) and synthesis reaction (PyNP). During the phosphorolysis reaction, guanosine is converted into guanine and ribose-1-phosphate (R-1-P) in the presence of PNP enzyme. The reaction intermediate R-1-P is then coupled to thymine in the presence of PyNP enzyme during the synthesis reaction, producing 5-MU. The process was scaled up from lab-scale to bench-scale (10 - 20 L) and demonstrated to be robust and reproducible. This is evident from the average guanosine conversion (94.7 percent ± 2.03) and 5-MU yield (88.2 percent ± 6.21) and mole balance (104 percent ± 7.61) which were obtained at bench-scale (3 replicates, 10 L). The reaction was carried out at reactor productivities of between 7 – 11 g.L-1.h-1. The integration of the biocatalytic process and chemical processes was successfully carried out, showing that 5-MU produced using our novel biocatalytic process behaved similarly to commercially available 5- MU (ex. Dayang Chemicals, China). A PCT patent application (Ref. No. P44422PC01) on this chemo-enzymatic process has been filed and currently public private partnerships are being explored through Arvir Technologies to evaluate and validate this technology at one ton scale.
- Full Text:
- Date Issued: 2010
Determination of social, environmental and economic benefits for community participation in forestry in Mpumalanga, South Africa
- Long, Leo Searle, Chirwa, Paxie
- Authors: Long, Leo Searle , Chirwa, Paxie
- Date: 2019
- Subjects: Forests and forestry -- South Africa -- Mpumalanga
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/34339 , vital:33307
- Description: Rural communities living adjacent to commercial forestry operations are often affected by numerous negative social issues such as poverty, unemployment, poor healthcare, and limited infrastructure, amongst others. In excess of 61% of forestry land managed by the state owned SAFCOL SOC Ltd is under land claim, as part of the Restitution of Land Rights Act (Act 22 of 1994). It is therefore necessary for forest companies to seek active means of engaging and partnering with these communities through a participatory forest management (PFM) approach. This study explored the sustainable (social, environmental and economic), benefits of such an approach as perceived (experienced) by these local rural communities, and specifically land claimants. The study was conducted in communities adjacent to SAFCOL plantations in the Mpumalanga Province of South Africa. Data were collected between May and June 2017 by means of a structured questionnaire. Surveys were conducted on 46 households within the identified communities so as to verify and evaluate perceived benefits in terms of forest products, ecosystem services and amenities/services/infrastructure provided by SAFCOL and the broader forest industry. The results indicated that these communities recognize and obtain numerous social, environmental and economic benefits from the forest including Non-Timber Forest Products (NTFPs) such as firewood; forest provisioning ecosystem services (FPESs) such as improved water quality; and more metaphysical benefits such as access to gravesites and the protection of traditions and customs. These benefits have the ability to improve the social well-being, economic independence, and the quality of environmental services obtained by the associated communities. It was however found that the utilization of these benefits was widely differentiated according to gender and land claimant status. Whilst males and females largely benefitted equally, there was a distinct benefit preference between genders for different NTFPs. For example males showed preference for the collection of building material, bush meat and for livestock husbandry, whilst females showed preference for the collection of firewood, medicinal plants and fruit, amongst others. Similarly, it was found that overall, non-land claimants benefited more than land claimants. Reasons for this are primarily due to the increased distance with which the land claimants live from the forest resource when compared to non-land claimants. The empirical value of the data produced through this study will be invaluable in negotiations with the land claimant communities on land settlement agreements, joint venture proposals, including Participatory Forest Management, and future land tenure. Through such inclusivity and vested interest in the sustainable management of the forests, corporate risk is reduced and community/land claimant relationships are reinforced. Such Participatory Forest Management arrangements are key to ensuring the longevity and resilience to the forest sector post-transfer of claimed land.
- Full Text:
- Date Issued: 2019
- Authors: Long, Leo Searle , Chirwa, Paxie
- Date: 2019
- Subjects: Forests and forestry -- South Africa -- Mpumalanga
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/34339 , vital:33307
- Description: Rural communities living adjacent to commercial forestry operations are often affected by numerous negative social issues such as poverty, unemployment, poor healthcare, and limited infrastructure, amongst others. In excess of 61% of forestry land managed by the state owned SAFCOL SOC Ltd is under land claim, as part of the Restitution of Land Rights Act (Act 22 of 1994). It is therefore necessary for forest companies to seek active means of engaging and partnering with these communities through a participatory forest management (PFM) approach. This study explored the sustainable (social, environmental and economic), benefits of such an approach as perceived (experienced) by these local rural communities, and specifically land claimants. The study was conducted in communities adjacent to SAFCOL plantations in the Mpumalanga Province of South Africa. Data were collected between May and June 2017 by means of a structured questionnaire. Surveys were conducted on 46 households within the identified communities so as to verify and evaluate perceived benefits in terms of forest products, ecosystem services and amenities/services/infrastructure provided by SAFCOL and the broader forest industry. The results indicated that these communities recognize and obtain numerous social, environmental and economic benefits from the forest including Non-Timber Forest Products (NTFPs) such as firewood; forest provisioning ecosystem services (FPESs) such as improved water quality; and more metaphysical benefits such as access to gravesites and the protection of traditions and customs. These benefits have the ability to improve the social well-being, economic independence, and the quality of environmental services obtained by the associated communities. It was however found that the utilization of these benefits was widely differentiated according to gender and land claimant status. Whilst males and females largely benefitted equally, there was a distinct benefit preference between genders for different NTFPs. For example males showed preference for the collection of building material, bush meat and for livestock husbandry, whilst females showed preference for the collection of firewood, medicinal plants and fruit, amongst others. Similarly, it was found that overall, non-land claimants benefited more than land claimants. Reasons for this are primarily due to the increased distance with which the land claimants live from the forest resource when compared to non-land claimants. The empirical value of the data produced through this study will be invaluable in negotiations with the land claimant communities on land settlement agreements, joint venture proposals, including Participatory Forest Management, and future land tenure. Through such inclusivity and vested interest in the sustainable management of the forests, corporate risk is reduced and community/land claimant relationships are reinforced. Such Participatory Forest Management arrangements are key to ensuring the longevity and resilience to the forest sector post-transfer of claimed land.
- Full Text:
- Date Issued: 2019
A business intelligence framework for supporting strategic sustainability information management in higher education
- Authors: Haupt, Ross
- Date: 2016
- Subjects: Business intelligence , Strategic planning -- Management
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10948/5319 , vital:20832
- Description: In the higher education sector, a number of Higher Education Institutions (HEIs) are playing a leading role in promoting sustainable initiatives. Effectively managing these initiatives however can be a complex task and requires data and information from multiple aspects of operations. In an HEI, operating sustainably means ensuring financial sustainability, social sustainability, environmental sustainability and educational sustainability. In order to manage sustainability effectively, HEIs require an integrated tool that can provide information on all areas of sustainability. HEIs face a number of challenges in effectively managing sustainability information, such as siloed data and information, and poor sharing and communication of information. Business Intelligence (BI) can assist in overcoming many of the challenges faced by organisations in effectively managing strategic sustainability information. This study investigates both the constraints to effective sustainability information management and the challenges of BI. A BI framework to support effective strategic sustainability information management is proposed. Nelson Mandela Metropolitan University (NMMU) is one such HEI, which is affected by the challenges of managing strategic sustainability information. NMMU is therefore used as a case study in this research. A BI solution, Sustainable BI, was developed based on the proposed framework. The main goal of sustainable BI is to provide strategic management at NMMU with a tool that can provide integrated sustainability information that can assist in overcoming the challenges in effectively managing strategic sustainability information. Sustainable BI was evaluated by strategic management at NMMU who are responsible for managing sustainability at NMMU. The evaluation took place through a usability study. The study revealed to what extent Sustainable BI could effectively manage strategic sustainability information at NMMU. The BI framework was iteratively improved on based on the results of the evaluations. The contributions from this study are a model for sustainability management, a BI Framework to support strategic sustainability information management and a BI solution, Sustainable BI.
- Full Text:
- Date Issued: 2016
- Authors: Haupt, Ross
- Date: 2016
- Subjects: Business intelligence , Strategic planning -- Management
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10948/5319 , vital:20832
- Description: In the higher education sector, a number of Higher Education Institutions (HEIs) are playing a leading role in promoting sustainable initiatives. Effectively managing these initiatives however can be a complex task and requires data and information from multiple aspects of operations. In an HEI, operating sustainably means ensuring financial sustainability, social sustainability, environmental sustainability and educational sustainability. In order to manage sustainability effectively, HEIs require an integrated tool that can provide information on all areas of sustainability. HEIs face a number of challenges in effectively managing sustainability information, such as siloed data and information, and poor sharing and communication of information. Business Intelligence (BI) can assist in overcoming many of the challenges faced by organisations in effectively managing strategic sustainability information. This study investigates both the constraints to effective sustainability information management and the challenges of BI. A BI framework to support effective strategic sustainability information management is proposed. Nelson Mandela Metropolitan University (NMMU) is one such HEI, which is affected by the challenges of managing strategic sustainability information. NMMU is therefore used as a case study in this research. A BI solution, Sustainable BI, was developed based on the proposed framework. The main goal of sustainable BI is to provide strategic management at NMMU with a tool that can provide integrated sustainability information that can assist in overcoming the challenges in effectively managing strategic sustainability information. Sustainable BI was evaluated by strategic management at NMMU who are responsible for managing sustainability at NMMU. The evaluation took place through a usability study. The study revealed to what extent Sustainable BI could effectively manage strategic sustainability information at NMMU. The BI framework was iteratively improved on based on the results of the evaluations. The contributions from this study are a model for sustainability management, a BI Framework to support strategic sustainability information management and a BI solution, Sustainable BI.
- Full Text:
- Date Issued: 2016
Use of flow reactors for an improved synthesis of Tenofovir derivatives
- Authors: Sonti, Thembela
- Date: 2023-04
- Subjects: Antiviral agents -- South Africa , HIV infections –Treatment
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/61190 , vital:69792
- Description: Tenofovir disoproxil fumarate (TDF) is a prescription drug used to treat and prevent human immunodeficiency virus (HIV) infections. It aids in the reduction of HIV in the body, allowing the immune system to function more effectively. This reduces the risk of HIV complications, such as infections, whilst improving the quality of life. TDF belongs to the nucleotide reverse transcriptase inhibitors category of drugs. These drugs limit the ability of the reverse transcriptase, an enzyme essential for each virus to replicate itself. A reduction in the cost of HIV treatment could improve supply security and make it more accessible to patients in need. Thus, this project aims to use flow technology to achieve a guaranteed supply chain and access. In this thesis, a method for the synthesis of TDF was developed using microreactors starting from the readily available adenine. The method was adapted from the traditional batch synthesis as currently there is no literature on the synthesis of TDF in flow chemistry. The batch methods used for the synthesis of the working standards were successfully translated to flow systems. For the best results to be obtained, optimisation of the reaction temperature, reagent molar equivalents and concentration was critical. From the optimisation studies, an improvement in conversion is evident throughout all stages. The flow synthesis of the first intermediate resulted in a conversion of 100 % in N,N-dimethylformamide in 6 min residence time. This study was conducted at 200 °C, which is higher than the boiling point of the solvent with the aid of a back pressure regulator. A key reagent in the synthesis of tenofovir, namely ((tosyloxy)methyl)phosphonic acid, had to be synthesised and it was successfully produced in 96 % yield. The second intermediate was synthesised through a successful coupling reaction between (R)-9-(2-hydroxypropyl)adenine and ((tosyloxy)methyl)- phosphonic acid, which afforded a 100 % conversion of tenofovir in 20 min total residence time. The multistep synthesis of tenofovir was a success as it afforded a 65 % overall conversion. The prodrug TDF was successfully synthesised at 120 °C with a 30 min residence time, yielding a conversion of 100 %. ii | P a g e This thesis consists of four chapters. Chapter one describes the background on HIV and a literature review on HIV drugs. This chapter also demonstrates flow chemistry and microreactors in detail and different routes for the synthesis of TDF in traditional batch methods. Chapter two provides a detailed methodology for batch synthesis and flow synthesis with analytical data. 1H-NMR, 13C-NMR and FTIR spectroscopy was used to evaluate all the compounds synthesised in this chapter. Chapter three thoroughly discusses the results that were obtained graphically, showing that the flow synthesis gives better yields than batch synthesis. In chapter 4, the conclusion of the whole investigation is stated along with the future work for the preparation of TDF. , Thesis (PhD) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2023
- Full Text:
- Date Issued: 2023-04
- Authors: Sonti, Thembela
- Date: 2023-04
- Subjects: Antiviral agents -- South Africa , HIV infections –Treatment
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/61190 , vital:69792
- Description: Tenofovir disoproxil fumarate (TDF) is a prescription drug used to treat and prevent human immunodeficiency virus (HIV) infections. It aids in the reduction of HIV in the body, allowing the immune system to function more effectively. This reduces the risk of HIV complications, such as infections, whilst improving the quality of life. TDF belongs to the nucleotide reverse transcriptase inhibitors category of drugs. These drugs limit the ability of the reverse transcriptase, an enzyme essential for each virus to replicate itself. A reduction in the cost of HIV treatment could improve supply security and make it more accessible to patients in need. Thus, this project aims to use flow technology to achieve a guaranteed supply chain and access. In this thesis, a method for the synthesis of TDF was developed using microreactors starting from the readily available adenine. The method was adapted from the traditional batch synthesis as currently there is no literature on the synthesis of TDF in flow chemistry. The batch methods used for the synthesis of the working standards were successfully translated to flow systems. For the best results to be obtained, optimisation of the reaction temperature, reagent molar equivalents and concentration was critical. From the optimisation studies, an improvement in conversion is evident throughout all stages. The flow synthesis of the first intermediate resulted in a conversion of 100 % in N,N-dimethylformamide in 6 min residence time. This study was conducted at 200 °C, which is higher than the boiling point of the solvent with the aid of a back pressure regulator. A key reagent in the synthesis of tenofovir, namely ((tosyloxy)methyl)phosphonic acid, had to be synthesised and it was successfully produced in 96 % yield. The second intermediate was synthesised through a successful coupling reaction between (R)-9-(2-hydroxypropyl)adenine and ((tosyloxy)methyl)- phosphonic acid, which afforded a 100 % conversion of tenofovir in 20 min total residence time. The multistep synthesis of tenofovir was a success as it afforded a 65 % overall conversion. The prodrug TDF was successfully synthesised at 120 °C with a 30 min residence time, yielding a conversion of 100 %. ii | P a g e This thesis consists of four chapters. Chapter one describes the background on HIV and a literature review on HIV drugs. This chapter also demonstrates flow chemistry and microreactors in detail and different routes for the synthesis of TDF in traditional batch methods. Chapter two provides a detailed methodology for batch synthesis and flow synthesis with analytical data. 1H-NMR, 13C-NMR and FTIR spectroscopy was used to evaluate all the compounds synthesised in this chapter. Chapter three thoroughly discusses the results that were obtained graphically, showing that the flow synthesis gives better yields than batch synthesis. In chapter 4, the conclusion of the whole investigation is stated along with the future work for the preparation of TDF. , Thesis (PhD) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2023
- Full Text:
- Date Issued: 2023-04
Benefication of glycerol from algae and vegetable oil
- Authors: Mafu, Lubabalo Rowan
- Date: 2011
- Subjects: Glycerin -- Biotechnology , Biodiesel fuels , Renewable natural resources
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10409 , http://hdl.handle.net/10948/d1011503 , Glycerin -- Biotechnology , Biodiesel fuels , Renewable natural resources
- Description: This research has been directed at furthering the utilization of crude glycerol oversupply formed as a by-product from the biodiesel manufacturing process. Phosphorylation of hydroxyl groups is a synthetic route that was investigated for the conversion of glycerol into a glycerol-phosphate (GPE) ester mixture. The process investigated for the synthesis of a GPE product was based on phosphorylation reaction procedures that were previously reported in the literature. The reaction to convert glycerol into a GPE mixture has been thoroughly investigated and the hydrogen chloride gas formed as a reaction by-product has been optimized. The chemical properties of GPE have been studied and discussed together with a mass balance of the overall glycerol phosphorylation process. The phosphate groups contained in polyhydric phosphate molecules have a potential chelating effect on cations. There are several cations that may be chelated by the phosphate ester group of polyhydric phosphate molecules. These cations include ammonium (NH4+), Potassium (K+), Calcium (Ca2+) etc, which are essential as nutrients in plant fertilizer formulations. This research has investigated the use of a GPE synthesized from glycerol in the laboratory and the use thereof as a phosphorus containing base in the formulation and evaluation of Nitrogen, Phosphorus and Potassium (NPK) containing fertilizer solution, Ammonium-Potassium-Glycerol-Phosphate (APGP) fertilizer solution. The APGP fertilizer solution has further been evaluated by growing two week old tomato seedlings under controlled conditions. The performance of the APGP fertiliser solution has been evaluated using design of experiments by comparison with traditionally used liquidAmmonium-Potassium-Phosphate inorganic fertilizer. This fertilizer solution has been prepared in similar manner as APGP formulation with the difference between them being the source of phosphorus. The results have been evaluated using statistic analysis where a significant difference between the evaluated fertilizer formulations was found. The comparative study of these formulations was monitored by the observed plant weights. A blank treatment was used as a control to determine if a significant difference among these formulations was observed. Anova single factor and t-Test methods (Two-Samples assumed of equal variances) are statistical models that were applied to interpret the observed experimental data with respect to wet and dry weighed masses of tomato seedlings. These methods indicated a confirmed conclusion that there was a significant difference between APPO4 solution and APGP solution. The observed data have shown that the APPO4 solution provided significantly better fertigation performance than APGP solution. Consequently, further investigation has been conducted to determine the cause of the poorer performance of the APGP solution. The further study of the APGP fertilizer solution included nutrient stability testing, biological analysis and other observed physical changes of the APGP solution over time. Biological results have revealed the presence of a Fusarium fungus species that has grown and is suspended in APGP fertilizer solution. This microbe species has been observed to play a vital role in consuming fertilizer nutrients. In addition, the observed abnormal plant growth and nutrient decomposition of the APGP formulation has been proposed to be mostly a result of the pathogenicity of the fusarium fungi species that was suspended in the APGP solution. Further work has been proposed in which the effect of such biological contamination is eliminated through adequate sterilization procedures and the APGP formulation re-evaluated.
- Full Text:
- Date Issued: 2011
- Authors: Mafu, Lubabalo Rowan
- Date: 2011
- Subjects: Glycerin -- Biotechnology , Biodiesel fuels , Renewable natural resources
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10409 , http://hdl.handle.net/10948/d1011503 , Glycerin -- Biotechnology , Biodiesel fuels , Renewable natural resources
- Description: This research has been directed at furthering the utilization of crude glycerol oversupply formed as a by-product from the biodiesel manufacturing process. Phosphorylation of hydroxyl groups is a synthetic route that was investigated for the conversion of glycerol into a glycerol-phosphate (GPE) ester mixture. The process investigated for the synthesis of a GPE product was based on phosphorylation reaction procedures that were previously reported in the literature. The reaction to convert glycerol into a GPE mixture has been thoroughly investigated and the hydrogen chloride gas formed as a reaction by-product has been optimized. The chemical properties of GPE have been studied and discussed together with a mass balance of the overall glycerol phosphorylation process. The phosphate groups contained in polyhydric phosphate molecules have a potential chelating effect on cations. There are several cations that may be chelated by the phosphate ester group of polyhydric phosphate molecules. These cations include ammonium (NH4+), Potassium (K+), Calcium (Ca2+) etc, which are essential as nutrients in plant fertilizer formulations. This research has investigated the use of a GPE synthesized from glycerol in the laboratory and the use thereof as a phosphorus containing base in the formulation and evaluation of Nitrogen, Phosphorus and Potassium (NPK) containing fertilizer solution, Ammonium-Potassium-Glycerol-Phosphate (APGP) fertilizer solution. The APGP fertilizer solution has further been evaluated by growing two week old tomato seedlings under controlled conditions. The performance of the APGP fertiliser solution has been evaluated using design of experiments by comparison with traditionally used liquidAmmonium-Potassium-Phosphate inorganic fertilizer. This fertilizer solution has been prepared in similar manner as APGP formulation with the difference between them being the source of phosphorus. The results have been evaluated using statistic analysis where a significant difference between the evaluated fertilizer formulations was found. The comparative study of these formulations was monitored by the observed plant weights. A blank treatment was used as a control to determine if a significant difference among these formulations was observed. Anova single factor and t-Test methods (Two-Samples assumed of equal variances) are statistical models that were applied to interpret the observed experimental data with respect to wet and dry weighed masses of tomato seedlings. These methods indicated a confirmed conclusion that there was a significant difference between APPO4 solution and APGP solution. The observed data have shown that the APPO4 solution provided significantly better fertigation performance than APGP solution. Consequently, further investigation has been conducted to determine the cause of the poorer performance of the APGP solution. The further study of the APGP fertilizer solution included nutrient stability testing, biological analysis and other observed physical changes of the APGP solution over time. Biological results have revealed the presence of a Fusarium fungus species that has grown and is suspended in APGP fertilizer solution. This microbe species has been observed to play a vital role in consuming fertilizer nutrients. In addition, the observed abnormal plant growth and nutrient decomposition of the APGP formulation has been proposed to be mostly a result of the pathogenicity of the fusarium fungi species that was suspended in the APGP solution. Further work has been proposed in which the effect of such biological contamination is eliminated through adequate sterilization procedures and the APGP formulation re-evaluated.
- Full Text:
- Date Issued: 2011
A contribution to the theory of prime modules
- Authors: Ssevviiri, David
- Date: 2013
- Subjects: Modules (Algebra) , Radical theory , Rings (Algebra)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10510 , http://hdl.handle.net/10948/d1019923
- Description: This thesis is aimed at generalizing notions of rings to modules. In par-ticular, notions of completely prime ideals, s-prime ideals, 2-primal rings and nilpotency of elements of rings are respectively generalized to completely prime submodules and classical completely prime submodules, s-prime submodules, 2-primal modules and nilpotency of elements of modules. Properties and rad-icals that arise from each of these notions are studied.
- Full Text:
- Date Issued: 2013
- Authors: Ssevviiri, David
- Date: 2013
- Subjects: Modules (Algebra) , Radical theory , Rings (Algebra)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10510 , http://hdl.handle.net/10948/d1019923
- Description: This thesis is aimed at generalizing notions of rings to modules. In par-ticular, notions of completely prime ideals, s-prime ideals, 2-primal rings and nilpotency of elements of rings are respectively generalized to completely prime submodules and classical completely prime submodules, s-prime submodules, 2-primal modules and nilpotency of elements of modules. Properties and rad-icals that arise from each of these notions are studied.
- Full Text:
- Date Issued: 2013
Social sustainability of biogas production in Sogwala village, lower Gweru district, Zimbabwe
- Authors: Dhliwayo, Nyaradzo
- Date: 2010
- Subjects: Biogas -- Zimbabwe , Biogas -- Developing countries , Sustainability -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10648 , http://hdl.handle.net/10948/1459 , Biogas -- Zimbabwe , Biogas -- Developing countries , Sustainability -- Zimbabwe
- Description: The study has explored the social sustainability of biogas production in a local village of Sogwala which is located in the Lower Gweru District of Zimbabwe. The social sustainability assessment was based on the two concepts of social sustainability, namely human capital and social capital with particular emphasis on their respective elements and aspects. Qualitative and quantitative research methodology methods were used on a sample of 100 households using biogas and some key informants. Analysis of the variance was used to determine whether biogas production could account for any effects on the social and human capital elements of the Sogwala community. An overview and descriptive statistics analysis of the findings from the study have been provided where the biogas users’ experiences, perspectives are discussed and results were assessed. For instance, effects on the aspects of social capital elements which include increases in the social group membership of households after the introduction of biogas production the village; the performance of biogas energy as compared with other fuel sources in terms of accessibility, efficiency and the degree of labour needed for continual production of biogas. In view of the human capital element, assessment is done on the economic status per household before and after the production of biogas, where emphasis is placed on the aspects of employment, education and health indicators within the social sustainability context. The fundamental benefits from biogas production are considered and discussed with the technical issues surrounding biogas production also being presented. This is not just a technical unit for providing alternative energy supply, but it requires management, labour and knowledge, skills to operate on a daily basis for it to have an impact that can bring positive change to the daily social lives of both the young and old.
- Full Text:
- Date Issued: 2010
- Authors: Dhliwayo, Nyaradzo
- Date: 2010
- Subjects: Biogas -- Zimbabwe , Biogas -- Developing countries , Sustainability -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10648 , http://hdl.handle.net/10948/1459 , Biogas -- Zimbabwe , Biogas -- Developing countries , Sustainability -- Zimbabwe
- Description: The study has explored the social sustainability of biogas production in a local village of Sogwala which is located in the Lower Gweru District of Zimbabwe. The social sustainability assessment was based on the two concepts of social sustainability, namely human capital and social capital with particular emphasis on their respective elements and aspects. Qualitative and quantitative research methodology methods were used on a sample of 100 households using biogas and some key informants. Analysis of the variance was used to determine whether biogas production could account for any effects on the social and human capital elements of the Sogwala community. An overview and descriptive statistics analysis of the findings from the study have been provided where the biogas users’ experiences, perspectives are discussed and results were assessed. For instance, effects on the aspects of social capital elements which include increases in the social group membership of households after the introduction of biogas production the village; the performance of biogas energy as compared with other fuel sources in terms of accessibility, efficiency and the degree of labour needed for continual production of biogas. In view of the human capital element, assessment is done on the economic status per household before and after the production of biogas, where emphasis is placed on the aspects of employment, education and health indicators within the social sustainability context. The fundamental benefits from biogas production are considered and discussed with the technical issues surrounding biogas production also being presented. This is not just a technical unit for providing alternative energy supply, but it requires management, labour and knowledge, skills to operate on a daily basis for it to have an impact that can bring positive change to the daily social lives of both the young and old.
- Full Text:
- Date Issued: 2010
A context-aware model to improve usability of information presented on mobile devices
- Authors: Ntawanga, Felix Fred
- Date: 2014
- Subjects: Context-aware computing , Online information services
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10495 , http://hdl.handle.net/10948/d1020768
- Description: Online information access on mobile devices is increasing as a result of the growth in the use of Internet-enabled handheld (or pocket-size) devices. The combined influence of recent enabling technologies such as Web 2.0, mobile app stores and improved wireless networks have driven the increase in online applications that allow users to access various types of information on mobile devices regardless of time and location. Examples of such applications (usually shortened to app) include: social media, such as FacebookTM App and TwitterTM App, banking applications such as (Standard Bank South Africa)TM Mobile Banking App and First National Bank (FNB) BankingTM App, and news application such as news 24TM App and BBCTM News App. Online businesses involved in buying, selling and business transaction processing activities via the Internet have exploited the opportunity to extend electronic commerce (e-commerce) initiatives into mobile commerce (m-commerce). Online businesses that interact with end user customers implement business to consumer (B2C) m-commerce applications that enable customers to access and browse product catalogue information on mobile devices, anytime, anywhere. Customers accessing electronic product catalogue information on a mobile device face a number of challenges such as a long list of products presented on a small screen and a longer information download time. These challenges mainly originate from the limiting and dynamic nature of the mobile apps operating environment, for example, dynamic location, bandwidth fluctuations and, diverse and limited device features, collectively referred to as context. The goal of this research was to design and implement a context-aware model that can be incorporated into an m-commerce application in order to improve the presentation of product catalogue information on m-commerce storefronts. The motivation for selecting product catalogue is prompted by literature which indicates that improved presentation of information in m-commerce (and e-commerce) applications has a positive impact on usability of the websites. Usable m-commerce (and e-commerce) websites improve efficiency in consumer behaviour that impacts sales, profits and business growth. The context-aware model aimed at collecting context information within the user environment and utilising it to determine optimal retrieval and presentation of product catalogue in m-commerce. An integrated logical context sensor and Mathematical algorithms were implemented in the context-aware model. The integrated logical context sensor was responsible for the collection of different types of predetermined context information such as device specification or capabilities, connection bandwidth, location and time of the day as well as the user profile. The algorithms transformed the collected context information into usable formats and enabled optimal retrieval and presentation of product catalogue data on a specific mobile device. Open-source implementation tools were utilised to implement components of the model including: HTML5, PhP, JavaScript and MySQL database. The context-aware model was incorporated into an existing m-commerce application. Two user evaluation studies were conducted during the course of the research. The first evaluation was to evaluate the accuracy of information collected by the context sensor component of the model. This survey was conducted with a sample of 30 users from different countries across the world. In-between the context sensor and main evaluation surveys, a pilot study was conducted with a sample of 19 users with great experience in mobile application development and use from SAP Next Business and Technology, Africa. Finally an overall user evaluation study was conducted with a sample of 30 users from a remote area called Kgautswane in Limpopo Province, South Africa. The results obtained indicate that the context-aware model was able to determine accurate context information in real-time and effectively determine how much product information should be retrieved and how the information should be presented on a mobile device interface. Two main contributions emerged from the research, first the research contributed to the field of mobile Human Computer Interaction. During the research, techniques of evaluating and improving usability of mobile applications were demonstrated. Secondly, the research made a significant contribution to the upcoming field of context-aware computing. The research brought clarity with regard to context-aware computing which is lacking in existing, current research despite the field’s proven impact of improving usability of applications. Researchers can utilise contributions made in this research to develop further techniques and usable context-aware solutions.
- Full Text:
- Date Issued: 2014
- Authors: Ntawanga, Felix Fred
- Date: 2014
- Subjects: Context-aware computing , Online information services
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10495 , http://hdl.handle.net/10948/d1020768
- Description: Online information access on mobile devices is increasing as a result of the growth in the use of Internet-enabled handheld (or pocket-size) devices. The combined influence of recent enabling technologies such as Web 2.0, mobile app stores and improved wireless networks have driven the increase in online applications that allow users to access various types of information on mobile devices regardless of time and location. Examples of such applications (usually shortened to app) include: social media, such as FacebookTM App and TwitterTM App, banking applications such as (Standard Bank South Africa)TM Mobile Banking App and First National Bank (FNB) BankingTM App, and news application such as news 24TM App and BBCTM News App. Online businesses involved in buying, selling and business transaction processing activities via the Internet have exploited the opportunity to extend electronic commerce (e-commerce) initiatives into mobile commerce (m-commerce). Online businesses that interact with end user customers implement business to consumer (B2C) m-commerce applications that enable customers to access and browse product catalogue information on mobile devices, anytime, anywhere. Customers accessing electronic product catalogue information on a mobile device face a number of challenges such as a long list of products presented on a small screen and a longer information download time. These challenges mainly originate from the limiting and dynamic nature of the mobile apps operating environment, for example, dynamic location, bandwidth fluctuations and, diverse and limited device features, collectively referred to as context. The goal of this research was to design and implement a context-aware model that can be incorporated into an m-commerce application in order to improve the presentation of product catalogue information on m-commerce storefronts. The motivation for selecting product catalogue is prompted by literature which indicates that improved presentation of information in m-commerce (and e-commerce) applications has a positive impact on usability of the websites. Usable m-commerce (and e-commerce) websites improve efficiency in consumer behaviour that impacts sales, profits and business growth. The context-aware model aimed at collecting context information within the user environment and utilising it to determine optimal retrieval and presentation of product catalogue in m-commerce. An integrated logical context sensor and Mathematical algorithms were implemented in the context-aware model. The integrated logical context sensor was responsible for the collection of different types of predetermined context information such as device specification or capabilities, connection bandwidth, location and time of the day as well as the user profile. The algorithms transformed the collected context information into usable formats and enabled optimal retrieval and presentation of product catalogue data on a specific mobile device. Open-source implementation tools were utilised to implement components of the model including: HTML5, PhP, JavaScript and MySQL database. The context-aware model was incorporated into an existing m-commerce application. Two user evaluation studies were conducted during the course of the research. The first evaluation was to evaluate the accuracy of information collected by the context sensor component of the model. This survey was conducted with a sample of 30 users from different countries across the world. In-between the context sensor and main evaluation surveys, a pilot study was conducted with a sample of 19 users with great experience in mobile application development and use from SAP Next Business and Technology, Africa. Finally an overall user evaluation study was conducted with a sample of 30 users from a remote area called Kgautswane in Limpopo Province, South Africa. The results obtained indicate that the context-aware model was able to determine accurate context information in real-time and effectively determine how much product information should be retrieved and how the information should be presented on a mobile device interface. Two main contributions emerged from the research, first the research contributed to the field of mobile Human Computer Interaction. During the research, techniques of evaluating and improving usability of mobile applications were demonstrated. Secondly, the research made a significant contribution to the upcoming field of context-aware computing. The research brought clarity with regard to context-aware computing which is lacking in existing, current research despite the field’s proven impact of improving usability of applications. Researchers can utilise contributions made in this research to develop further techniques and usable context-aware solutions.
- Full Text:
- Date Issued: 2014
A smart home environment simulation tool to support the recognition of activities of daily living
- Authors: Ho, Brandon
- Date: 2020
- Subjects: Artificial intelligence , Internet of things Home automation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/49334 , vital:41622
- Description: The prevalence of internet of things technologies and internet-connected devices enables the potential of introducing intelligence to a wide range of applications and fields. Smart homes are popular application of internet of things. Smart homes refer to domestic environments that can monitor their own state and the state of their inhabitants. Smart homes are identified as a promising solution for assisting inhabitants in completing daily activities and improving quality of life for inhabitants. This dissertation discusses the design and implementation of smart home simulation tool prototype, called smart environment stimulation (SESim). SESim is designed to conduct smart home simulation and generate synthetic sensor datasets which describe activity performances. This dissertation also discusses the evaluation of SESim, which focused on validating the utility of conducting smart home simulations and generating sensor datasets.
- Full Text: false
- Date Issued: 2020
- Authors: Ho, Brandon
- Date: 2020
- Subjects: Artificial intelligence , Internet of things Home automation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/49334 , vital:41622
- Description: The prevalence of internet of things technologies and internet-connected devices enables the potential of introducing intelligence to a wide range of applications and fields. Smart homes are popular application of internet of things. Smart homes refer to domestic environments that can monitor their own state and the state of their inhabitants. Smart homes are identified as a promising solution for assisting inhabitants in completing daily activities and improving quality of life for inhabitants. This dissertation discusses the design and implementation of smart home simulation tool prototype, called smart environment stimulation (SESim). SESim is designed to conduct smart home simulation and generate synthetic sensor datasets which describe activity performances. This dissertation also discusses the evaluation of SESim, which focused on validating the utility of conducting smart home simulations and generating sensor datasets.
- Full Text: false
- Date Issued: 2020
The role of Venda culture in nature conservation : a case study of the inhabitants of the Tshivhase area
- Khorommbi, Konanani Christopher
- Authors: Khorommbi, Konanani Christopher
- Date: 2001
- Subjects: Nature conservation -- South Africa -- Venda , Venda (South Africa)
- Language: English
- Type: Thesis , Masters , MTech (Nature Conservation)
- Identifier: vital:10975 , http://hdl.handle.net/10948/d1002119 , Nature conservation -- South Africa -- Venda , Venda (South Africa)
- Description: This thesis investigates the role of Venda culture in nature conservation and natural resource management. The project is based on the premise that the survival of human beings is entirely dependent on the extent to which different cultures conserve the natural environment. The researcher assumes that the scientific approach is not the only one that is capable of addressing environmental issues but that indigenous technology has a positive role to play. The study specifically looks at the relationship between the Venda culture and conservation of land, water, plants and animals. In order to achieve this goal, the study was divided into five chapters. The introductory chapter includes the statement of problem, delimitations of the study, the definitions of concepts, the assumptions, and the significance of the study. The literature review provides an overview of the indigenous strategies of nature conservation and natural resource management from a broader international approach to a specifically Venda approach. The researcher looked at the cultural perspective of the four areas under investigation. This chapter is followed by themethodological justification that discusses the social survey as a researchmethod for carrying out this study. The results presented in the fourth chapter comprise raw data from the three sectors of respondents, namely traditional leaders, traditional healers and villagers. Under each item, common responses have been grouped together for presentation and specific responses for the three sectors were presented independently from one another. This has provided the researcher with the opportunity to identify areas of similarities and differences among the three sectors. Both complementary and conflicting ideas are summarised and used as a basis for analysis. The results reflect a high degree of agreement among respondents. The discussion in chapter five was based on the results and relevant literature. The researcher’s approach was to depict the most common views among the three sectors and their conservation implications. In the discussion, the strengths and weaknesses of the Venda cultural approach were exposed in relation to the five sub-problems under investigation. The recognition of the Venda indigenous technology of natural resource management has been proposed because of its importance in nature conservation. In the recommendations the formulation of policy that overlooks local values was criticised. The use of the Venda approach as a basis for the development of conservation projects was strongly recommended. Lastly, itwas proposed that further investigations of specific aspects of the Venda cultural be considered for possible incorporation in future management of the natural environment.
- Full Text:
- Date Issued: 2001
- Authors: Khorommbi, Konanani Christopher
- Date: 2001
- Subjects: Nature conservation -- South Africa -- Venda , Venda (South Africa)
- Language: English
- Type: Thesis , Masters , MTech (Nature Conservation)
- Identifier: vital:10975 , http://hdl.handle.net/10948/d1002119 , Nature conservation -- South Africa -- Venda , Venda (South Africa)
- Description: This thesis investigates the role of Venda culture in nature conservation and natural resource management. The project is based on the premise that the survival of human beings is entirely dependent on the extent to which different cultures conserve the natural environment. The researcher assumes that the scientific approach is not the only one that is capable of addressing environmental issues but that indigenous technology has a positive role to play. The study specifically looks at the relationship between the Venda culture and conservation of land, water, plants and animals. In order to achieve this goal, the study was divided into five chapters. The introductory chapter includes the statement of problem, delimitations of the study, the definitions of concepts, the assumptions, and the significance of the study. The literature review provides an overview of the indigenous strategies of nature conservation and natural resource management from a broader international approach to a specifically Venda approach. The researcher looked at the cultural perspective of the four areas under investigation. This chapter is followed by themethodological justification that discusses the social survey as a researchmethod for carrying out this study. The results presented in the fourth chapter comprise raw data from the three sectors of respondents, namely traditional leaders, traditional healers and villagers. Under each item, common responses have been grouped together for presentation and specific responses for the three sectors were presented independently from one another. This has provided the researcher with the opportunity to identify areas of similarities and differences among the three sectors. Both complementary and conflicting ideas are summarised and used as a basis for analysis. The results reflect a high degree of agreement among respondents. The discussion in chapter five was based on the results and relevant literature. The researcher’s approach was to depict the most common views among the three sectors and their conservation implications. In the discussion, the strengths and weaknesses of the Venda cultural approach were exposed in relation to the five sub-problems under investigation. The recognition of the Venda indigenous technology of natural resource management has been proposed because of its importance in nature conservation. In the recommendations the formulation of policy that overlooks local values was criticised. The use of the Venda approach as a basis for the development of conservation projects was strongly recommended. Lastly, itwas proposed that further investigations of specific aspects of the Venda cultural be considered for possible incorporation in future management of the natural environment.
- Full Text:
- Date Issued: 2001
Development of Palladium selective reagents and materials
- Authors: Moyo, Cyprian Bertrand
- Date: 2016
- Subjects: Palladium Palladium compounds -- Industrial applications Chemistry, Inorganic
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/12231 , vital:27046
- Description: The adsorption and separation of Pd(II) from Pt(IV), Ir(IV) and Rh(III) by silica microparticles functionalized with triethylenetetramine (TETA), 2-(2-aminoethylthio)ethanamine (NSN) and 2-(2-(2-aminoethyl)ethylthio)ethanamine (NSSN) in 1 M hydrochloric acid medium was investigated by continuous column studies. The functionalized sorbent materials were characterized by microanalysis, SEM-EDS and FT-IR. Palladium selectivity of the sorbent materials was achieved by stripping of rhodium, iridium and platinum chlorido species with 0.5 M of NaClO4 in 1 M HCl while [PdCl4]2 was eluted with 3% w/v thiourea. The desorption efficiency of thiourea was confirmed by the SEM-EDS analysis of the materials after Pd(II) elution. Palladium loading capacity of the sorbents were in the order S-NSSN (23.85 mg/g) > S-NSN (12.70 mg/g) > S-TETA (4.97 mg/g). The extraction patterns on the sorbent materials were explained by considering the coordination chemistry of the ligand with [PdCl4]2ˉ and ionic interactions of [PtCl6]2ˉ and [IrCl5(H2O]ˉ. The square planar complexes, [Pd(HNSSNH)Cl2]Cl2 and [Pd(NSNH)Cl2][PdCl4]2, were isolated, analyzed by spectroscopy and single crystal X-ray, whereas evidence of the fraction of Pd(II)-TETA complex was obtained by HPLC studies. This provided proof of the inner sphere coordination mechanism as the mode of interaction of these ligands with [PdCl4]2ˉ. Trace amounts of Brˉ anions in ligands resulted in the inadvertent isolation of bromide coordinated Pd(II) NSN and NSSN complexes. The ion-pair salts of [TETAH4]4+ with [PtCl6]2ˉ, [IrCl6]3ˉ and [RhCl6]3ˉ were also isolated and characterized by microanalysis and IR to further explain the extraction patterns.
- Full Text:
- Date Issued: 2016
- Authors: Moyo, Cyprian Bertrand
- Date: 2016
- Subjects: Palladium Palladium compounds -- Industrial applications Chemistry, Inorganic
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/12231 , vital:27046
- Description: The adsorption and separation of Pd(II) from Pt(IV), Ir(IV) and Rh(III) by silica microparticles functionalized with triethylenetetramine (TETA), 2-(2-aminoethylthio)ethanamine (NSN) and 2-(2-(2-aminoethyl)ethylthio)ethanamine (NSSN) in 1 M hydrochloric acid medium was investigated by continuous column studies. The functionalized sorbent materials were characterized by microanalysis, SEM-EDS and FT-IR. Palladium selectivity of the sorbent materials was achieved by stripping of rhodium, iridium and platinum chlorido species with 0.5 M of NaClO4 in 1 M HCl while [PdCl4]2 was eluted with 3% w/v thiourea. The desorption efficiency of thiourea was confirmed by the SEM-EDS analysis of the materials after Pd(II) elution. Palladium loading capacity of the sorbents were in the order S-NSSN (23.85 mg/g) > S-NSN (12.70 mg/g) > S-TETA (4.97 mg/g). The extraction patterns on the sorbent materials were explained by considering the coordination chemistry of the ligand with [PdCl4]2ˉ and ionic interactions of [PtCl6]2ˉ and [IrCl5(H2O]ˉ. The square planar complexes, [Pd(HNSSNH)Cl2]Cl2 and [Pd(NSNH)Cl2][PdCl4]2, were isolated, analyzed by spectroscopy and single crystal X-ray, whereas evidence of the fraction of Pd(II)-TETA complex was obtained by HPLC studies. This provided proof of the inner sphere coordination mechanism as the mode of interaction of these ligands with [PdCl4]2ˉ. Trace amounts of Brˉ anions in ligands resulted in the inadvertent isolation of bromide coordinated Pd(II) NSN and NSSN complexes. The ion-pair salts of [TETAH4]4+ with [PtCl6]2ˉ, [IrCl6]3ˉ and [RhCl6]3ˉ were also isolated and characterized by microanalysis and IR to further explain the extraction patterns.
- Full Text:
- Date Issued: 2016
A comparison between the game and hunting industries in KwaZulu-Natal and the Eastern Cape
- Authors: Kobus, Louann
- Date: 2007
- Subjects: Big game hunting -- South Africa -- KwaZulu-Natal , Big game hunting -- South Africa -- Eastern Cape , Hunting -- South Africa -- KwaZulu-Natal , Hunting -- South Africa -- Eastern Cape , Game farms -- South Africa -- KwaZulu-Natal , Game farms -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10590 , http://hdl.handle.net/10948/534 , http://hdl.handle.net/10948/d1011724 , Big game hunting -- South Africa -- KwaZulu-Natal , Big game hunting -- South Africa -- Eastern Cape , Hunting -- South Africa -- KwaZulu-Natal , Hunting -- South Africa -- Eastern Cape , Game farms -- South Africa -- KwaZulu-Natal , Game farms -- South Africa -- Eastern Cape
- Description: The objectives of this research, were to investigate the characteristics and develop a profile of the game and hunting industries of KwaZulu-Natal, and to undertake a comparison between the game and hunting industries in KwaZulu-Natal and the Eastern Cape. The comparative part of this study was completed using results obtained from a study done in 2002 in the Eastern Cape (van Niekerk, 2002). The main farming activities in KwaZulu-Natal are large livestock production and sugar cane production. In recent years, private landowners in KwaZulu-Natal have undergone a transition from livestock production to game ranching due to the problems faced and the cost implications of the HIV epidemic, stock theft, difficulties faced with changes in the labour laws and the increasing number of land claims against farmers. Although the game and hunting industries are relatively young industries in KwaZulu-Natal they contribute significantly to the economy of the province. Not only is greater conservation of the biodiversity more effective in game ranching but it is also proving to yield great economic returns. The increase in game ranching in recent years is namely due to the monetary value placed on wildlife, the increased value in ecotourism and its value as an earner of foreign exchange, less dependency on unskilled labour than that of livestock farming and lower rates of animal loss through theft compared to that of livestock farming. In KwaZulu-Natal game numbers indicate that impala have the greatest population amongst the respondents, followed by nyala, blesbok, common reedbuck, kudu and blue wildebeest, whilst other game species occur in smaller numbers. Respondents in KwaZulu-Natal indicate that nyala is the largest economic earner for them followed by buffalo, whereas in the Eastern Cape (2002), kudu and springbok provide the greatest income for the province. In KwaZulu-Natal income generated from hunting is second to that of live game sales compared to the Eastern Cape (2002) where hunting is the most important form of game utilisation in terms of income generated. At the time of this study, respondents in KwaZulu-Natal reported an income of R 15 382 397 generated from live sales and R 13 561 459 from hunting. These respondents also indicated that the total value of game utilised annually was in excess of R 30 million. Although game utilisation is occurring on a sustainable basis, there is room for greater utilisation of some game species which, if undertaken correctly, can increase the revenue for the province significantly and also contribute positively to further sustainability of the game populations. KwaZulu-Natal’s competitive advantage is derived from the fact that there is an abundance of game on the ranches, quality trophy animals are available, the number of game species available for hunting and quality of service rendered to hunters by the professional hunters and ranch owners. This study has clearly shown that there is a need for further investigation into the game and hunting industries in KwaZulu-Natal.
- Full Text:
- Date Issued: 2007
- Authors: Kobus, Louann
- Date: 2007
- Subjects: Big game hunting -- South Africa -- KwaZulu-Natal , Big game hunting -- South Africa -- Eastern Cape , Hunting -- South Africa -- KwaZulu-Natal , Hunting -- South Africa -- Eastern Cape , Game farms -- South Africa -- KwaZulu-Natal , Game farms -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10590 , http://hdl.handle.net/10948/534 , http://hdl.handle.net/10948/d1011724 , Big game hunting -- South Africa -- KwaZulu-Natal , Big game hunting -- South Africa -- Eastern Cape , Hunting -- South Africa -- KwaZulu-Natal , Hunting -- South Africa -- Eastern Cape , Game farms -- South Africa -- KwaZulu-Natal , Game farms -- South Africa -- Eastern Cape
- Description: The objectives of this research, were to investigate the characteristics and develop a profile of the game and hunting industries of KwaZulu-Natal, and to undertake a comparison between the game and hunting industries in KwaZulu-Natal and the Eastern Cape. The comparative part of this study was completed using results obtained from a study done in 2002 in the Eastern Cape (van Niekerk, 2002). The main farming activities in KwaZulu-Natal are large livestock production and sugar cane production. In recent years, private landowners in KwaZulu-Natal have undergone a transition from livestock production to game ranching due to the problems faced and the cost implications of the HIV epidemic, stock theft, difficulties faced with changes in the labour laws and the increasing number of land claims against farmers. Although the game and hunting industries are relatively young industries in KwaZulu-Natal they contribute significantly to the economy of the province. Not only is greater conservation of the biodiversity more effective in game ranching but it is also proving to yield great economic returns. The increase in game ranching in recent years is namely due to the monetary value placed on wildlife, the increased value in ecotourism and its value as an earner of foreign exchange, less dependency on unskilled labour than that of livestock farming and lower rates of animal loss through theft compared to that of livestock farming. In KwaZulu-Natal game numbers indicate that impala have the greatest population amongst the respondents, followed by nyala, blesbok, common reedbuck, kudu and blue wildebeest, whilst other game species occur in smaller numbers. Respondents in KwaZulu-Natal indicate that nyala is the largest economic earner for them followed by buffalo, whereas in the Eastern Cape (2002), kudu and springbok provide the greatest income for the province. In KwaZulu-Natal income generated from hunting is second to that of live game sales compared to the Eastern Cape (2002) where hunting is the most important form of game utilisation in terms of income generated. At the time of this study, respondents in KwaZulu-Natal reported an income of R 15 382 397 generated from live sales and R 13 561 459 from hunting. These respondents also indicated that the total value of game utilised annually was in excess of R 30 million. Although game utilisation is occurring on a sustainable basis, there is room for greater utilisation of some game species which, if undertaken correctly, can increase the revenue for the province significantly and also contribute positively to further sustainability of the game populations. KwaZulu-Natal’s competitive advantage is derived from the fact that there is an abundance of game on the ranches, quality trophy animals are available, the number of game species available for hunting and quality of service rendered to hunters by the professional hunters and ranch owners. This study has clearly shown that there is a need for further investigation into the game and hunting industries in KwaZulu-Natal.
- Full Text:
- Date Issued: 2007
An evaluation of UPLC technology for the simultaneous analysis of actives in a multi-active drug
- Authors: Bawjee, Janita
- Date: 2011
- Subjects: High performance liquid chromatography
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10384 , http://hdl.handle.net/10948/d1008407 , High performance liquid chromatography
- Description: The evaluation of the potential to use Ultra Performance Liquid Chromatography (UPLC) for the simultaneous quantification of all the actives in a multi-active tablet is described in this work. Part of the evaluation was to ensure that the necessary regulatory requirements were adhered to by ascertaining that an analytical method is suitable for a specific purpose through analytical method validation for the specific multi-active tablet. The UPLC method was also tested for the analysis of similar products, namely tablet formulations that contain similar active ingredients in the same proportions but with an additional active ingredient. A method for the simultaneous determination of paracetamol, caffeine and codeine phosphate was developed using UPLC technology. The UPLC developed method was more efficient than the existing in-house HPLC method. The UPLC method was then validated in accordance to ICH and USP guidelines. The application of this UPLC method for the analysis of similar products containing paracetamol, caffeine, codeine phosphate and one extra active ingredient was very challenging. The low concentration of the additional component, differences in sample matrix and differences in formulations added to the challenges. The direct application for the analysis of products Y and Z was not successful; however the method could be used as a platform for further research. A cost comparison between the UPLC and HPLC methods showed the UPLC method to be more cost effective. Thus, while maintenance costs are higher for the UPLC instrument, column costs are comparable to HPLC columns, but solvent and waste disposal charges decrease considerably due to lower solvent use. The reduction in instrument time dramatically improves the cost effectiveness of UPLC over HPLC due to a concurrent reduction in analyst time requirement. The results of this study show that the analytical costs associated with the analysis of multi-active drugs using HPLC procedures can be reduced substantially by the CONFIDENTIAL INTELLECTUAL PROPERTY OF ASPEN PHARMACARE implementation of UPLC technology. The hypothesis that the enhanced chromatographic power of UPLC can be leveraged to provide faster analysis times hence increased product throughput rates, and lower operating costs for the analysis of multi-active drugs was accepted. These advantages were achieved whilst meeting all regulatory requirements for analytical methods as required by regulatory bodies.
- Full Text:
- Date Issued: 2011
- Authors: Bawjee, Janita
- Date: 2011
- Subjects: High performance liquid chromatography
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10384 , http://hdl.handle.net/10948/d1008407 , High performance liquid chromatography
- Description: The evaluation of the potential to use Ultra Performance Liquid Chromatography (UPLC) for the simultaneous quantification of all the actives in a multi-active tablet is described in this work. Part of the evaluation was to ensure that the necessary regulatory requirements were adhered to by ascertaining that an analytical method is suitable for a specific purpose through analytical method validation for the specific multi-active tablet. The UPLC method was also tested for the analysis of similar products, namely tablet formulations that contain similar active ingredients in the same proportions but with an additional active ingredient. A method for the simultaneous determination of paracetamol, caffeine and codeine phosphate was developed using UPLC technology. The UPLC developed method was more efficient than the existing in-house HPLC method. The UPLC method was then validated in accordance to ICH and USP guidelines. The application of this UPLC method for the analysis of similar products containing paracetamol, caffeine, codeine phosphate and one extra active ingredient was very challenging. The low concentration of the additional component, differences in sample matrix and differences in formulations added to the challenges. The direct application for the analysis of products Y and Z was not successful; however the method could be used as a platform for further research. A cost comparison between the UPLC and HPLC methods showed the UPLC method to be more cost effective. Thus, while maintenance costs are higher for the UPLC instrument, column costs are comparable to HPLC columns, but solvent and waste disposal charges decrease considerably due to lower solvent use. The reduction in instrument time dramatically improves the cost effectiveness of UPLC over HPLC due to a concurrent reduction in analyst time requirement. The results of this study show that the analytical costs associated with the analysis of multi-active drugs using HPLC procedures can be reduced substantially by the CONFIDENTIAL INTELLECTUAL PROPERTY OF ASPEN PHARMACARE implementation of UPLC technology. The hypothesis that the enhanced chromatographic power of UPLC can be leveraged to provide faster analysis times hence increased product throughput rates, and lower operating costs for the analysis of multi-active drugs was accepted. These advantages were achieved whilst meeting all regulatory requirements for analytical methods as required by regulatory bodies.
- Full Text:
- Date Issued: 2011
Microstructural characterization of Swift Heavy Ion (SHI) induced rotation in single crystal NiO
- Authors: Douglas-Henry, Danielle
- Date: 2021-12
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/53648 , vital:45685
- Description: Swift Heavy Ions (SHI) are characterised by having energies greater than 1 MeV per nucleon with an atomic mass greater than 6 amu. Exposure to irradiation of this type has been known to produce latent tracks in insulators. This is due to the energy loss through the material being governed by electronic excitation processes. The extent of the track formation and microstructural changes induced has been reported to be material specific. Models such as the thermal spike model have been used to explain these changes, however rough approximations are still made. A particularly under studied phenomena is the collective rotation seen in materials exposed to off-normal incidence irradiation. To date the only available experimental data is X-Ray Diffraction (XRD) spectra and surface shifts. This does not allow for depth-dependent rotation studies and very little can be deduced regarding the microstructure of the modified volume. In this study, the microstructural changes in single crystal Nickel Oxide (NiO) have been studied using electron microscopy techniques. A depth dependent investigation of the crystal rotation was performed using Selected Area Electron Diffraction (SAED), Transmission Kikuchi Diffraction (TKD) and Electron Backscatter Diffraction (EBSD). Transmission Electron Microscopy (TEM) and Scanning Transmission Electron Microscopy (STEM) were utilized to interrogate the microstructural changes facilitating the bulk rotation. Five different NiO specimens were investigated. Specimens had surfaces parallel to either the {0 0 1} or {1 1 1} planes. Ion energies used were 593 MeV, 940 MeV and 1.6 GeV, while fluences ranged from 1.0 x 1011 ions/cm² to 9.6 x 1014 ions/cm². Latent track formation in both low fluence (nonoverlapping regime) and high fluence (overlapping regime) specimens were investigated and compared. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2021
- Full Text: false
- Date Issued: 2021-12
- Authors: Douglas-Henry, Danielle
- Date: 2021-12
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/53648 , vital:45685
- Description: Swift Heavy Ions (SHI) are characterised by having energies greater than 1 MeV per nucleon with an atomic mass greater than 6 amu. Exposure to irradiation of this type has been known to produce latent tracks in insulators. This is due to the energy loss through the material being governed by electronic excitation processes. The extent of the track formation and microstructural changes induced has been reported to be material specific. Models such as the thermal spike model have been used to explain these changes, however rough approximations are still made. A particularly under studied phenomena is the collective rotation seen in materials exposed to off-normal incidence irradiation. To date the only available experimental data is X-Ray Diffraction (XRD) spectra and surface shifts. This does not allow for depth-dependent rotation studies and very little can be deduced regarding the microstructure of the modified volume. In this study, the microstructural changes in single crystal Nickel Oxide (NiO) have been studied using electron microscopy techniques. A depth dependent investigation of the crystal rotation was performed using Selected Area Electron Diffraction (SAED), Transmission Kikuchi Diffraction (TKD) and Electron Backscatter Diffraction (EBSD). Transmission Electron Microscopy (TEM) and Scanning Transmission Electron Microscopy (STEM) were utilized to interrogate the microstructural changes facilitating the bulk rotation. Five different NiO specimens were investigated. Specimens had surfaces parallel to either the {0 0 1} or {1 1 1} planes. Ion energies used were 593 MeV, 940 MeV and 1.6 GeV, while fluences ranged from 1.0 x 1011 ions/cm² to 9.6 x 1014 ions/cm². Latent track formation in both low fluence (nonoverlapping regime) and high fluence (overlapping regime) specimens were investigated and compared. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2021
- Full Text: false
- Date Issued: 2021-12
Cluster analysis for group selection in launch sales predictions
- Authors: Watchurst, Lee
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Cluster analysis
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52003 , vital:43447
- Description: One way for businesses to stay ahead in a competitive market is through the launch of new products and planning for these launches optimally. This includes ordering the correct quantity of stock in advance as well as maintaining these stock levels while the item launches. However, holding too much stock in warehouses can affect the business costs adversely. This research proposes the use of cluster analysis techniques to determine the up-front purchase quantity by identifying similar items and using their initial quantities sold. Products will be grouped based on their numerical and categorical attributes. Once the data is clustered, the Bass model will be used to obtain a sales profile for the new item. The Bass model is a popular choice for product life cycle planning due to the emphasis placed on the timing of adoption. The study will make use of data from a retail and wholesale company that sells, in part, single use items. With the planning for new launches being a key problem point in many companies, this research aims to optimise the planning process and ensure product launch success across stores. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2021
- Full Text: false
- Date Issued: 2021-04
- Authors: Watchurst, Lee
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Cluster analysis
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52003 , vital:43447
- Description: One way for businesses to stay ahead in a competitive market is through the launch of new products and planning for these launches optimally. This includes ordering the correct quantity of stock in advance as well as maintaining these stock levels while the item launches. However, holding too much stock in warehouses can affect the business costs adversely. This research proposes the use of cluster analysis techniques to determine the up-front purchase quantity by identifying similar items and using their initial quantities sold. Products will be grouped based on their numerical and categorical attributes. Once the data is clustered, the Bass model will be used to obtain a sales profile for the new item. The Bass model is a popular choice for product life cycle planning due to the emphasis placed on the timing of adoption. The study will make use of data from a retail and wholesale company that sells, in part, single use items. With the planning for new launches being a key problem point in many companies, this research aims to optimise the planning process and ensure product launch success across stores. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2021
- Full Text: false
- Date Issued: 2021-04
Analysis of the interaction between recombinant human Beta2 integrin I-domains and CD23
- Authors: Sprong, Kaitlin
- Date: 2014
- Subjects: Immune response -- Regulation , Immunoglobulins , CD23 antigen
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10362 , http://hdl.handle.net/10948/d1021078
- Description: In order to further elucidate the interaction between CD23 and β2 integrins (CD11b/CD18) the following objectives were established: Expression and purification of CD11b I-domain as a GST-fusion protein using Escherichia coli; Cloning, synthesis and expression of CD18 I-Like domain.CD11b I-domain has previously been expressed as a GST-fusion protein (Daniels, 2010) and consequently led to comparable expression of CD18 I-like domain as a GST-fusion protein; Preparation of two site-directed mutants of CD18 I-Like domain in order to study the function of the serine residue involved in the S116P mutation. The serine was mutated to proline, as in LAD patients, as well as alanine, a non-polar alternative, in order to contrast and compare binding characteristics. Expression, refolding and purification of sCD23, and a double mutatedsCD23 (RKΔAA) from E. coli; This was performed according to the method described by Daniels et al. (2005); Investigation of the CD23-CD11b I-like domain interaction through surface plasmon resonance spectroscopy.
- Full Text:
- Date Issued: 2014
- Authors: Sprong, Kaitlin
- Date: 2014
- Subjects: Immune response -- Regulation , Immunoglobulins , CD23 antigen
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10362 , http://hdl.handle.net/10948/d1021078
- Description: In order to further elucidate the interaction between CD23 and β2 integrins (CD11b/CD18) the following objectives were established: Expression and purification of CD11b I-domain as a GST-fusion protein using Escherichia coli; Cloning, synthesis and expression of CD18 I-Like domain.CD11b I-domain has previously been expressed as a GST-fusion protein (Daniels, 2010) and consequently led to comparable expression of CD18 I-like domain as a GST-fusion protein; Preparation of two site-directed mutants of CD18 I-Like domain in order to study the function of the serine residue involved in the S116P mutation. The serine was mutated to proline, as in LAD patients, as well as alanine, a non-polar alternative, in order to contrast and compare binding characteristics. Expression, refolding and purification of sCD23, and a double mutatedsCD23 (RKΔAA) from E. coli; This was performed according to the method described by Daniels et al. (2005); Investigation of the CD23-CD11b I-like domain interaction through surface plasmon resonance spectroscopy.
- Full Text:
- Date Issued: 2014
Synthesis and characterization of iron doped sodium and potassium titanates using the pechini sol-gel method
- Authors: Guga, Aluwani
- Date: 2021-12
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/53646 , vital:45683
- Description: Iron doped (Fe: 5Ti) sodium and potassium titanates were prepared by the Pechini sol-gel method and calcined at 800 °C. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectrometry (EDS), FTIR and Raman spectroscopy were used to characterize the structure and morphology of the titanate nanomaterials. A quantitative XRD analysis using Rietveld refinement of the titanates confirmed the powders to consist of crystalline phases with the Na2Ti7O15 and K2Ti8O17 phases predominant for the sodium and potassium titanate, respectively. This was further confirmed using selected area electron diffraction (SAED) in the TEM. SEM and TEM analyses indicated that the titanates are consistent with a nanostructured material exhibiting rod-like morphology. The elemental compositions of the titanites were examined by SEM-EDS and TEM-EDS and found to agree well with the targeted Fe to Ti ratio from synthesis. Limited evidence for the segregation of iron in the titanate regions were found indicating the iron to be incorporated within the titanate lattice. Electron energy loss spectroscopy (EELS) fine-structure analysis of the Fe L2,3 core-loss edge was successfully used to match the Fe to a 2+ or 3+ valence state, consistent with its occupation at Ti lattice sites. Finally, Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy were used to study the vibrational modes of the functional group of the sodium and potassium titanates. Vibrational modes consistent with previously reported findings for the titanate phases identified were found with no evidence of isolated Fe related modes. , Thesis (MSc) -- Faculty of Science, Computer Science, Mathematics, Physics and Statistics, 2021
- Full Text: false
- Date Issued: 2021-12
- Authors: Guga, Aluwani
- Date: 2021-12
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/53646 , vital:45683
- Description: Iron doped (Fe: 5Ti) sodium and potassium titanates were prepared by the Pechini sol-gel method and calcined at 800 °C. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectrometry (EDS), FTIR and Raman spectroscopy were used to characterize the structure and morphology of the titanate nanomaterials. A quantitative XRD analysis using Rietveld refinement of the titanates confirmed the powders to consist of crystalline phases with the Na2Ti7O15 and K2Ti8O17 phases predominant for the sodium and potassium titanate, respectively. This was further confirmed using selected area electron diffraction (SAED) in the TEM. SEM and TEM analyses indicated that the titanates are consistent with a nanostructured material exhibiting rod-like morphology. The elemental compositions of the titanites were examined by SEM-EDS and TEM-EDS and found to agree well with the targeted Fe to Ti ratio from synthesis. Limited evidence for the segregation of iron in the titanate regions were found indicating the iron to be incorporated within the titanate lattice. Electron energy loss spectroscopy (EELS) fine-structure analysis of the Fe L2,3 core-loss edge was successfully used to match the Fe to a 2+ or 3+ valence state, consistent with its occupation at Ti lattice sites. Finally, Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy were used to study the vibrational modes of the functional group of the sodium and potassium titanates. Vibrational modes consistent with previously reported findings for the titanate phases identified were found with no evidence of isolated Fe related modes. , Thesis (MSc) -- Faculty of Science, Computer Science, Mathematics, Physics and Statistics, 2021
- Full Text: false
- Date Issued: 2021-12