Biosulphidogenic hydrolysis of lignin and lignin model compounds
- Authors: Madikane, Mzekelo
- Date: 2002
- Subjects: Lignin Lignin -- Biodegradation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3917 , http://hdl.handle.net/10962/d1003976
- Description: Lignin degradation under biosulphidogenic conditions has not been extensively reported in the literature. Although aerobic degradation of lignin is well documented, anaerobic biodegradation has focused mainly on methanogenic systems with biosulphidogenic systems receiving less attention. Sulphate reducing bacteria are known to generate moderately high levels of both sulphide and alkalinity at room temperatures, and these conditions draw some comparison with the Kraft pulping process. In the Kraft pulping process, lignin is degraded chemically at ±170°C under high sulphide and alkaline conditions and may provide a model for understanding biosulphidogenic lignin degrading activity. The aim of this study was to investigate the biosulphidogenic hydrolysis of lignin within the context of the chemical and biological conditions generated by a mixed sulphate reducing bacteria consortia. Bioreactor studies with a mixed sulphate reducing consortia and pine wood powder (both untreated and depectinated) resulted in the generation of comparable levels of sulphide and alkalinity used in the chemical hydrolysis studies. Aromatic compound yields were between 20 to 50% of the chemical hydrolysis studies. This fluctuation may have been due to the utilization of these aromatic compounds as electron donors by the sulphate reducing consortia as evidenced by the high rate of sulphate reduction in both the untreated and depectinated wood bioreactors. Biodegradation of lignin model compounds was investigated in order to elucidate lignin degradation mechanisms. Both mono-aromatic and dimeric lignin model compounds were used as electron donors and carbon sources for the mixed sulphate reducing consortia. Biodegradation and mass spectrometer analysis of mono-aromatic compounds, ferulic acid and ferulic acid ethyl ester resulted in the production of intermediates such as catechol, cyclohexane carboxylic acid and adipic acid. These intermediates were also observed in the degradation of dimeric ferulic acid. Biodegradation of salicin resulted in the production of salicyl alcohol, ortho-cresol and acetate. Biodegradation of benzylic ether resulted in the production of vanillin and acetate as end products. The results of these studies provide evidence for a biosulphidogenic hydrolysis of lignin, and also the utilisation of lignin-derived aromatic compounds as electron donor sources, by a mixed sulphate reducing consortia.
- Full Text:
- Date Issued: 2002
- Authors: Madikane, Mzekelo
- Date: 2002
- Subjects: Lignin Lignin -- Biodegradation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3917 , http://hdl.handle.net/10962/d1003976
- Description: Lignin degradation under biosulphidogenic conditions has not been extensively reported in the literature. Although aerobic degradation of lignin is well documented, anaerobic biodegradation has focused mainly on methanogenic systems with biosulphidogenic systems receiving less attention. Sulphate reducing bacteria are known to generate moderately high levels of both sulphide and alkalinity at room temperatures, and these conditions draw some comparison with the Kraft pulping process. In the Kraft pulping process, lignin is degraded chemically at ±170°C under high sulphide and alkaline conditions and may provide a model for understanding biosulphidogenic lignin degrading activity. The aim of this study was to investigate the biosulphidogenic hydrolysis of lignin within the context of the chemical and biological conditions generated by a mixed sulphate reducing bacteria consortia. Bioreactor studies with a mixed sulphate reducing consortia and pine wood powder (both untreated and depectinated) resulted in the generation of comparable levels of sulphide and alkalinity used in the chemical hydrolysis studies. Aromatic compound yields were between 20 to 50% of the chemical hydrolysis studies. This fluctuation may have been due to the utilization of these aromatic compounds as electron donors by the sulphate reducing consortia as evidenced by the high rate of sulphate reduction in both the untreated and depectinated wood bioreactors. Biodegradation of lignin model compounds was investigated in order to elucidate lignin degradation mechanisms. Both mono-aromatic and dimeric lignin model compounds were used as electron donors and carbon sources for the mixed sulphate reducing consortia. Biodegradation and mass spectrometer analysis of mono-aromatic compounds, ferulic acid and ferulic acid ethyl ester resulted in the production of intermediates such as catechol, cyclohexane carboxylic acid and adipic acid. These intermediates were also observed in the degradation of dimeric ferulic acid. Biodegradation of salicin resulted in the production of salicyl alcohol, ortho-cresol and acetate. Biodegradation of benzylic ether resulted in the production of vanillin and acetate as end products. The results of these studies provide evidence for a biosulphidogenic hydrolysis of lignin, and also the utilisation of lignin-derived aromatic compounds as electron donor sources, by a mixed sulphate reducing consortia.
- Full Text:
- Date Issued: 2002
Broken vessels : the im-possibility of the art of remembrance and re-collection in the work of Anselm Kiefer, Christian Boltanski, William Kentridge and Santu Mofokeng
- Authors: Belluigi, Dina Zoe
- Date: 2002
- Subjects: History in art Kiefer, Anselm, 1945- Boltanski, Christian, 1944- Kentridge, William, 1955- Mofokeng, Santu, 1956-
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2395 , http://hdl.handle.net/10962/d1002191
- Description: This thesis is structured around investigating the philosophical and aesthetic problematics, politics, and possibilities of representing the past for the purposes of demythifying the present as well as commemorating the losses of history, as explored in the artworks of Anselm Kiefer, Christian Boltanski, William Kentridge and Santu Mofokeng. The first chapter begins with Theodor Adorno’s philosophical understanding of myth and history: how he is influenced by and then develops Karl Marx’s critique of society, Sigmund Freud’s critique of reason and its subject, and particularly Walter Benjamin’s ideas of history as catastrophe, the role of the historian and his messianic materialism. The second section looks at Theodor Adorno’s dialectic of art and society: immanent criticism in aesthetic practice, mimesis, and the shift in conceptions of allegory from Walter Benjamin’s understanding to that of Jacques Derrida. The last section of the chapter looks at Jacques Derrida’s poststructuralist theories against boundary-fixing, within that the ethical relation to the ‘other’ and the theorist/artist as psychic exile. The second chapter deals with the politics of remembrance and representation — beginning with Theodor Adorno’s historic interpretation of the Mosaic law against the making of images and Jean-Francois Lyotard on the im-possibility of representing the unrepresentable. The chapter is divided in two parts between the post-Holocaust European artists Anselm Kiefer and Christian Boltanski, and the post-apartheid South African artists William Kentridge and Santu Mofokeng. It explores, within these artists’ specific contexts, their formal and philosophical approaches to myth and history, and the problematics of image-making, representing the unrepresentable, and commemorating the immemorial. The thesis concludes by considering different conceptions of melancholia as they relate to these artists: the Freudian psychoanalytic approach, Benjamin’s notions of the artist-genius, and Julia Kristeva’s Lacanian reading of the humanist melancholic, concluding with the mythic-historical Kaballist notion of melancholia as the historical burden or responsibility to commemorate loss.
- Full Text:
- Date Issued: 2002
- Authors: Belluigi, Dina Zoe
- Date: 2002
- Subjects: History in art Kiefer, Anselm, 1945- Boltanski, Christian, 1944- Kentridge, William, 1955- Mofokeng, Santu, 1956-
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2395 , http://hdl.handle.net/10962/d1002191
- Description: This thesis is structured around investigating the philosophical and aesthetic problematics, politics, and possibilities of representing the past for the purposes of demythifying the present as well as commemorating the losses of history, as explored in the artworks of Anselm Kiefer, Christian Boltanski, William Kentridge and Santu Mofokeng. The first chapter begins with Theodor Adorno’s philosophical understanding of myth and history: how he is influenced by and then develops Karl Marx’s critique of society, Sigmund Freud’s critique of reason and its subject, and particularly Walter Benjamin’s ideas of history as catastrophe, the role of the historian and his messianic materialism. The second section looks at Theodor Adorno’s dialectic of art and society: immanent criticism in aesthetic practice, mimesis, and the shift in conceptions of allegory from Walter Benjamin’s understanding to that of Jacques Derrida. The last section of the chapter looks at Jacques Derrida’s poststructuralist theories against boundary-fixing, within that the ethical relation to the ‘other’ and the theorist/artist as psychic exile. The second chapter deals with the politics of remembrance and representation — beginning with Theodor Adorno’s historic interpretation of the Mosaic law against the making of images and Jean-Francois Lyotard on the im-possibility of representing the unrepresentable. The chapter is divided in two parts between the post-Holocaust European artists Anselm Kiefer and Christian Boltanski, and the post-apartheid South African artists William Kentridge and Santu Mofokeng. It explores, within these artists’ specific contexts, their formal and philosophical approaches to myth and history, and the problematics of image-making, representing the unrepresentable, and commemorating the immemorial. The thesis concludes by considering different conceptions of melancholia as they relate to these artists: the Freudian psychoanalytic approach, Benjamin’s notions of the artist-genius, and Julia Kristeva’s Lacanian reading of the humanist melancholic, concluding with the mythic-historical Kaballist notion of melancholia as the historical burden or responsibility to commemorate loss.
- Full Text:
- Date Issued: 2002
Building brand loyalty within selected segments of the South African fast moving consumer goods market
- Authors: Terblanche, Etienne
- Date: 2002
- Language: English
- Type: Thesis , Masters , MTech (Marketing)
- Identifier: vital:10774 , http://hdl.handle.net/10948/d1002108
- Description: The rapidly increasing competitiveness within the fast-moving consumer goods (FMCG) market compels an organisation within this market to not only entice consumers to purchase the organisation’s brand, but also to keep these consumers purchasing the brand. It is therefore essential that an organisation creates and maintains loyalty among consumers towards its brand. The objective of the research was to find out what strategies an organisation could implement to achieve and sustain loyalty from current and prospective consumers towards its brand in a highly competitive, FMCG market. The main areas of focus were as follows: Establishing the basis on which consumers differentiate between homogenous products. Determining what strategies an organisation could utilise to ensure that consumers will differentiate its brand from those of competitors. Obtaining relevant information to find out what variables motivate consumers to be brand loyal within the FMCG market. Ascertaining how an organisation could build a brand. Determining how an organisation could maintain brand loyalty from its existing consumers. The research included a study of relevant literature and an empirical study. The aim of the literature study was to obtain a solid base of information and opinions regarding the concepts of brands and building brand loyalty. Making use of structured questionnaires and through performing personal interviews, the empirical study consisted of two aspects. The one aspect was a brand loyalty survey conducted among 303 respondents, and the second aspect was a brand loyalty survey conducted with nine owners or marketers of leading brands. The following were the major findings of the research: Relying on being a leader in price and quality is not enough to ensure that a consumer would continue purchasing an organisation’s brand. A brand is an experience and in order for a consumer to become loyal towards a brand, the consumer should have a host of positive thoughts regarding past experience with the brand. It is essential that organisations within the FMCG market proactively develop and implement strategies aimed at creating and maintaining loyalty towards their brands.
- Full Text:
- Date Issued: 2002
- Authors: Terblanche, Etienne
- Date: 2002
- Language: English
- Type: Thesis , Masters , MTech (Marketing)
- Identifier: vital:10774 , http://hdl.handle.net/10948/d1002108
- Description: The rapidly increasing competitiveness within the fast-moving consumer goods (FMCG) market compels an organisation within this market to not only entice consumers to purchase the organisation’s brand, but also to keep these consumers purchasing the brand. It is therefore essential that an organisation creates and maintains loyalty among consumers towards its brand. The objective of the research was to find out what strategies an organisation could implement to achieve and sustain loyalty from current and prospective consumers towards its brand in a highly competitive, FMCG market. The main areas of focus were as follows: Establishing the basis on which consumers differentiate between homogenous products. Determining what strategies an organisation could utilise to ensure that consumers will differentiate its brand from those of competitors. Obtaining relevant information to find out what variables motivate consumers to be brand loyal within the FMCG market. Ascertaining how an organisation could build a brand. Determining how an organisation could maintain brand loyalty from its existing consumers. The research included a study of relevant literature and an empirical study. The aim of the literature study was to obtain a solid base of information and opinions regarding the concepts of brands and building brand loyalty. Making use of structured questionnaires and through performing personal interviews, the empirical study consisted of two aspects. The one aspect was a brand loyalty survey conducted among 303 respondents, and the second aspect was a brand loyalty survey conducted with nine owners or marketers of leading brands. The following were the major findings of the research: Relying on being a leader in price and quality is not enough to ensure that a consumer would continue purchasing an organisation’s brand. A brand is an experience and in order for a consumer to become loyal towards a brand, the consumer should have a host of positive thoughts regarding past experience with the brand. It is essential that organisations within the FMCG market proactively develop and implement strategies aimed at creating and maintaining loyalty towards their brands.
- Full Text:
- Date Issued: 2002
Building project management within financial institutions, a comparative assessment
- Authors: Van Tonder, Anthony David
- Date: 2002
- Subjects: Project management , Financial institutions -- Management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10893 , http://hdl.handle.net/10948/79 , Project management , Financial institutions -- Management
- Description: The expenditure by financial institutions in South Africa on building projects could conservatively be estimated to total in the region of a billion rand per annum. It is surprising, given the amount of money being spent that there is currently no co-operation between the various financial institutions in the field of building project management. The research in this study found that most financial institutions were not taking into account all the costs and benefits when undertaking a project. When a project is undertaken in this manner, the viability analysis would not be a true reflection of the project being undertaken. The areas which were not taken into account when undertaking a project were the indirect project costs, which included costs like the project management staff themselves. An exception to this was First National Bank Metropolitan Delivery. They followed an outsourcing strategy in terms of their building project management function and the cost of this was known and added into the project cost. In terms of the benefits, this study found that the financial institutions do not take the intangible benefits into account. They do not consider the long term benefits which will be derived as a result of the implementation of a project. Arriving at a model which takes into account these factors, would provide material for a Doctorate thesis.
- Full Text:
- Date Issued: 2002
- Authors: Van Tonder, Anthony David
- Date: 2002
- Subjects: Project management , Financial institutions -- Management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10893 , http://hdl.handle.net/10948/79 , Project management , Financial institutions -- Management
- Description: The expenditure by financial institutions in South Africa on building projects could conservatively be estimated to total in the region of a billion rand per annum. It is surprising, given the amount of money being spent that there is currently no co-operation between the various financial institutions in the field of building project management. The research in this study found that most financial institutions were not taking into account all the costs and benefits when undertaking a project. When a project is undertaken in this manner, the viability analysis would not be a true reflection of the project being undertaken. The areas which were not taken into account when undertaking a project were the indirect project costs, which included costs like the project management staff themselves. An exception to this was First National Bank Metropolitan Delivery. They followed an outsourcing strategy in terms of their building project management function and the cost of this was known and added into the project cost. In terms of the benefits, this study found that the financial institutions do not take the intangible benefits into account. They do not consider the long term benefits which will be derived as a result of the implementation of a project. Arriving at a model which takes into account these factors, would provide material for a Doctorate thesis.
- Full Text:
- Date Issued: 2002
Can formal language planning link to grassroots cultural initiatives?: an informal investigation
- Authors: Wright, Laurence
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:7041 , http://hdl.handle.net/10962/d1007381
- Description: Formal language planning is inevitably a top-down, highly technical process. Success for such planning would seem to depend on engaging productively with existing or readily developed social motivation within the society. This article reports on an informal investigation into how ordinary language practitioners and cultural workers in South Africa view the possibilities of contributing to the country’s emerging language dispensation, what they regard as their most useful possible contributions, and what they expect from the language planners and ‘government’ in support of South Africa’s Language Policy and Plan.
- Full Text:
- Date Issued: 2002
- Authors: Wright, Laurence
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:7041 , http://hdl.handle.net/10962/d1007381
- Description: Formal language planning is inevitably a top-down, highly technical process. Success for such planning would seem to depend on engaging productively with existing or readily developed social motivation within the society. This article reports on an informal investigation into how ordinary language practitioners and cultural workers in South Africa view the possibilities of contributing to the country’s emerging language dispensation, what they regard as their most useful possible contributions, and what they expect from the language planners and ‘government’ in support of South Africa’s Language Policy and Plan.
- Full Text:
- Date Issued: 2002
CANS: Customizable Alarm Notification System, an H. 323 Signalling Service
- Authors: Penton, J , Terzoli, Alfredo
- Date: 2002
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427562 , vital:72447 , https://www.cs.ru.ac.za/research/g97p5142/Docs/CANSSATNAC2002.pdf
- Description: H. 323 is a standardized signalling protocol for Voice over IP (VoIP) networks, which defines the terminal equipment and services that ena-ble real-time multimedia (data, voice, and video) communication over packetbased networks. One of the major advantages of carrying voice over Computer Networks, as opposed to the traditional SCN, is the pos-sibility of creating a wealth of services and integrating them into the network with minimal time and cost. Among these services, exists a subset that may need to interact at the signalling layer and H. 323 (ver-sion 4) provides mechanisms for this. This paper focuses on an appli-cation that was developed to explore and demonstrate H. 323’s signal-ling service creation and extension mechanisms.
- Full Text:
- Date Issued: 2002
- Authors: Penton, J , Terzoli, Alfredo
- Date: 2002
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427562 , vital:72447 , https://www.cs.ru.ac.za/research/g97p5142/Docs/CANSSATNAC2002.pdf
- Description: H. 323 is a standardized signalling protocol for Voice over IP (VoIP) networks, which defines the terminal equipment and services that ena-ble real-time multimedia (data, voice, and video) communication over packetbased networks. One of the major advantages of carrying voice over Computer Networks, as opposed to the traditional SCN, is the pos-sibility of creating a wealth of services and integrating them into the network with minimal time and cost. Among these services, exists a subset that may need to interact at the signalling layer and H. 323 (ver-sion 4) provides mechanisms for this. This paper focuses on an appli-cation that was developed to explore and demonstrate H. 323’s signal-ling service creation and extension mechanisms.
- Full Text:
- Date Issued: 2002
Case studies of equivalent fuzzy subgroups of finite abelian groups
- Authors: Ngcibi, Sakhile L
- Date: 2002
- Subjects: Abelian groups , Fuzzy sets
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5401 , http://hdl.handle.net/10962/d1005215 , Abelian groups , Fuzzy sets
- Description: The broad goal is to classify all fuzzy subgroups of a given type of finite group. P.S. Das introduced the ntion of level subgroups to characterize fuzzy subgroups of finite grouops. The notion of equivalence of fuzzy subgroups which is used in this thesis was first introduced by Murali and Makamba. We use this equivalence to charterise fuzzy subgroups of inite Abelian groups (p-groups in particular) for a specified prime p. We characterize some crisp subgroups of p-groups and investigate some cases on equi valent fuzzy subgroups.
- Full Text:
- Date Issued: 2002
- Authors: Ngcibi, Sakhile L
- Date: 2002
- Subjects: Abelian groups , Fuzzy sets
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5401 , http://hdl.handle.net/10962/d1005215 , Abelian groups , Fuzzy sets
- Description: The broad goal is to classify all fuzzy subgroups of a given type of finite group. P.S. Das introduced the ntion of level subgroups to characterize fuzzy subgroups of finite grouops. The notion of equivalence of fuzzy subgroups which is used in this thesis was first introduced by Murali and Makamba. We use this equivalence to charterise fuzzy subgroups of inite Abelian groups (p-groups in particular) for a specified prime p. We characterize some crisp subgroups of p-groups and investigate some cases on equi valent fuzzy subgroups.
- Full Text:
- Date Issued: 2002
Catalytic behaviour of metallophthalocyanines towards the detection of nitric oxide
- Authors: Vilakazi, Lea Sibulelo
- Date: 2002
- Subjects: Electrochemistry Nitric oxide
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4418 , http://hdl.handle.net/10962/d1006852
- Description: Electrocatalytic reduction and oxidation of nitric oxide (NO) using cobalt phthalocyanine complexes have been studied and compared to vitamin B₁₂ and other metallophthalocyanine (MPc) complexes. Modifying a glassy carbon electrode with these complexes resulted in improved sensitivity of the electrode allowing detection of NO to 10⁻⁹ mol dm⁻³. The mechanisms of catalysis were studied. Electrocatalysis of NO involves coordination of NO to the MPc complex. Hence catalytic activity is affected by the nature of the metal center. However coordination of NO to the MPc complex has to be reversible to eliminate poisoning of the electrode. Though FePc gave the best sensitivity and lowered the reduction potential more than CoPc, the strong Fe-NO bond resulted in the poisoning of the electrode hence, rendering the electrode unstable. Rate constants for NO coordination to the MPc complexes were studied. These rates were smaller than the studied NO porphyrin coordination rates. Electrocatalytic reduction of NO using MPc complexes involves a transfer of an electron from the metal center to the NO ligand. Hence, substitution of electron-donating grohps on the cobalt pthalocyanine complex resulted in improved sensitivity and catalytic activity. A CoPc modified microelectrode (11μm) was used to monitor NO in human blood components and to detect NO in a rat brain. Detections of NO were also done in aqueous solutions in the presence of interfering species such as dopamine and serotonin. An interaction between NO and serotonin was observed.
- Full Text:
- Date Issued: 2002
- Authors: Vilakazi, Lea Sibulelo
- Date: 2002
- Subjects: Electrochemistry Nitric oxide
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4418 , http://hdl.handle.net/10962/d1006852
- Description: Electrocatalytic reduction and oxidation of nitric oxide (NO) using cobalt phthalocyanine complexes have been studied and compared to vitamin B₁₂ and other metallophthalocyanine (MPc) complexes. Modifying a glassy carbon electrode with these complexes resulted in improved sensitivity of the electrode allowing detection of NO to 10⁻⁹ mol dm⁻³. The mechanisms of catalysis were studied. Electrocatalysis of NO involves coordination of NO to the MPc complex. Hence catalytic activity is affected by the nature of the metal center. However coordination of NO to the MPc complex has to be reversible to eliminate poisoning of the electrode. Though FePc gave the best sensitivity and lowered the reduction potential more than CoPc, the strong Fe-NO bond resulted in the poisoning of the electrode hence, rendering the electrode unstable. Rate constants for NO coordination to the MPc complexes were studied. These rates were smaller than the studied NO porphyrin coordination rates. Electrocatalytic reduction of NO using MPc complexes involves a transfer of an electron from the metal center to the NO ligand. Hence, substitution of electron-donating grohps on the cobalt pthalocyanine complex resulted in improved sensitivity and catalytic activity. A CoPc modified microelectrode (11μm) was used to monitor NO in human blood components and to detect NO in a rat brain. Detections of NO were also done in aqueous solutions in the presence of interfering species such as dopamine and serotonin. An interaction between NO and serotonin was observed.
- Full Text:
- Date Issued: 2002
Chemical studies of selected chromone derivatives
- Authors: Nchinda, Aloysius Tchangwe
- Date: 2002
- Subjects: Heterocyclic compounds
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4434 , http://hdl.handle.net/10962/d1007442
- Description: This investigation has been geared towards several aspects of chromone chemistry. Selected 2-(N,N-dimethylarnino)chromones have been synthesized via 2-hydroxyacetophenone boron difluoride complex intermediates, and potentiometric analysis of these compounds in ethanolwater has been used to determine the influence of substituents on their basicity. The pKa values have been found to lie within a narrow range (1.92 - 2.52), and the observed substituent effects have been rationalized with the aid of semi-empirical and ab initio molecular orbital calculations. An efficient route has been developed for the synthesis of the naturally-occurring chromone, "granulosin" [7,8-(methylenedioxy)-2-propylchromone], and several C-2 side chain analogues in good yields, by condensing 2'-hydroxy-3',4'-(methylenedioxy)acetophenone with a range of ethyl carboxylate esters. These compounds show significant cytotoxic activity against the brine shrimp, Artemia salina, and two of them, the 2-ethyl and 2-benzyl derivatives also show 100% activity as pesticides on Beet army worms (BAW). Another naturally-occurring chromone derivative, 5-hydroxy-2-isopropyl-7-methoxychromone, and four C-2 side chain analogues have been prepared in moderate yields. These compounds also show significant cytotoxic activity against the brine shrimp, Artemia salina, and it is apparent that the presence of the hydroxyl group at C-5 is critical for such activity. The electronimpact mass spectra of both series of chromone derivatives have been investigated, permitting the elucidation of characteristic fragmentation patterns. In work directed towards the synthesis of potential HIV -1 protease inhibitors, five novel chromone-containing analogues of the clinically useful drug, ritonavir, have been synthesized. The design strategy has involved the coupling of substituted chromone-2- carboxylic acids with a specially prepared, hydroxyethylene dipeptide isostere to afford ritonavir analogues containing chromone termini. An interactive docking procedure has been used to explore the docking of ritonavir and the novel chromone-containing analogues into ' the active site of the enzyme, and has indicated the capacity of the ritonavir analogues to form hydrogen-bonds with the HJV-l enzyme receptor. Various substituted cbromone-3-carbaldehydes, which have been synthesized from the corresponding o-hyclroxyacetophenones using Vilsmeier-Haack methodology, have been examined as substrates for Morita-Baylis-Hillman reactions, using 3-hyclroxyquinuclidine as the catalyst and arcylonitrile and methyl acrylate as the activated alkenes. Optimization of the reaction conditions has permitted efficient conversion of the cbromone-3-carbaldehydes to the Morita-Baylis-Hillman products and, in some cases, dimeric products, within 24 h. Heating of the Morita-Baylis-Hillman products, arising from reactions with methyl acrylate, at 80 ºC for 3 h in the presence of DABCO as catalyst, has been shown to effect transformation to the corresponding dimers in good yield.
- Full Text:
- Date Issued: 2002
- Authors: Nchinda, Aloysius Tchangwe
- Date: 2002
- Subjects: Heterocyclic compounds
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4434 , http://hdl.handle.net/10962/d1007442
- Description: This investigation has been geared towards several aspects of chromone chemistry. Selected 2-(N,N-dimethylarnino)chromones have been synthesized via 2-hydroxyacetophenone boron difluoride complex intermediates, and potentiometric analysis of these compounds in ethanolwater has been used to determine the influence of substituents on their basicity. The pKa values have been found to lie within a narrow range (1.92 - 2.52), and the observed substituent effects have been rationalized with the aid of semi-empirical and ab initio molecular orbital calculations. An efficient route has been developed for the synthesis of the naturally-occurring chromone, "granulosin" [7,8-(methylenedioxy)-2-propylchromone], and several C-2 side chain analogues in good yields, by condensing 2'-hydroxy-3',4'-(methylenedioxy)acetophenone with a range of ethyl carboxylate esters. These compounds show significant cytotoxic activity against the brine shrimp, Artemia salina, and two of them, the 2-ethyl and 2-benzyl derivatives also show 100% activity as pesticides on Beet army worms (BAW). Another naturally-occurring chromone derivative, 5-hydroxy-2-isopropyl-7-methoxychromone, and four C-2 side chain analogues have been prepared in moderate yields. These compounds also show significant cytotoxic activity against the brine shrimp, Artemia salina, and it is apparent that the presence of the hydroxyl group at C-5 is critical for such activity. The electronimpact mass spectra of both series of chromone derivatives have been investigated, permitting the elucidation of characteristic fragmentation patterns. In work directed towards the synthesis of potential HIV -1 protease inhibitors, five novel chromone-containing analogues of the clinically useful drug, ritonavir, have been synthesized. The design strategy has involved the coupling of substituted chromone-2- carboxylic acids with a specially prepared, hydroxyethylene dipeptide isostere to afford ritonavir analogues containing chromone termini. An interactive docking procedure has been used to explore the docking of ritonavir and the novel chromone-containing analogues into ' the active site of the enzyme, and has indicated the capacity of the ritonavir analogues to form hydrogen-bonds with the HJV-l enzyme receptor. Various substituted cbromone-3-carbaldehydes, which have been synthesized from the corresponding o-hyclroxyacetophenones using Vilsmeier-Haack methodology, have been examined as substrates for Morita-Baylis-Hillman reactions, using 3-hyclroxyquinuclidine as the catalyst and arcylonitrile and methyl acrylate as the activated alkenes. Optimization of the reaction conditions has permitted efficient conversion of the cbromone-3-carbaldehydes to the Morita-Baylis-Hillman products and, in some cases, dimeric products, within 24 h. Heating of the Morita-Baylis-Hillman products, arising from reactions with methyl acrylate, at 80 ºC for 3 h in the presence of DABCO as catalyst, has been shown to effect transformation to the corresponding dimers in good yield.
- Full Text:
- Date Issued: 2002
Continuity and generalized continuity in dynamics and other applications
- Authors: Mimna, Roy Allan
- Date: 2002
- Subjects: Topological dynamics -- Research Dynamics -- Mathematical models -- Research Perturbation (Mathematics) Attractors (Mathematics) Baire classes Mathematics -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5404 , http://hdl.handle.net/10962/d1005218
- Description: The topological dynamics of continuous and noncontinuous dynamical systems are investigated. Various definitions of chaos are studied, as well as notions of stability. Results are obtained on asymptotically stable sets and the perturbation stability of such sets. The primary focus is on the traditional point sets of topological dynamics, including the chain recurrent set, omega-limit sets and attractors. The basic setting is that of a continuous function on a compact metric space, sometimes with additional properties on the space. The investigation includes results on the dynamical properties of typical continuous functions in the sense of Baire category. Results are also developed concerning dynamical systems involving quasi-continuous functions. An invariance property for the omega-limit sets of such functions is given. Omega-limit sets are characterized for Riemann integrable derivatives and derivatiyes which are continuous almost everywhere. Techniques used in the investigation and formulation of results include finding theorems which relate the rather disparate notions of dynamical properties and generalized continuity. In addition to dynamical systems, numerous other applications of generalized continuity are imoestigated. Techniques used include application of the Baire Category Theorem and the notion of semi-closure. For example, results are formulated concerning functions determined by dense sets, including separately continuous functions, thus generalizing the classical result for continuous functions on dense subsets of the domain. The uniform boundedness theorem is extended to functions which are not necessarily continuous, including various derivatives. The closed graph theorem is strictly generalized in two separate ways, and applications are presented using these generalizations. An invariance property of separately continuous functions is given. Cluster sets are studied in connection with separate continuity, and various results are presented concerning locally bounded functions.
- Full Text:
- Date Issued: 2002
- Authors: Mimna, Roy Allan
- Date: 2002
- Subjects: Topological dynamics -- Research Dynamics -- Mathematical models -- Research Perturbation (Mathematics) Attractors (Mathematics) Baire classes Mathematics -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5404 , http://hdl.handle.net/10962/d1005218
- Description: The topological dynamics of continuous and noncontinuous dynamical systems are investigated. Various definitions of chaos are studied, as well as notions of stability. Results are obtained on asymptotically stable sets and the perturbation stability of such sets. The primary focus is on the traditional point sets of topological dynamics, including the chain recurrent set, omega-limit sets and attractors. The basic setting is that of a continuous function on a compact metric space, sometimes with additional properties on the space. The investigation includes results on the dynamical properties of typical continuous functions in the sense of Baire category. Results are also developed concerning dynamical systems involving quasi-continuous functions. An invariance property for the omega-limit sets of such functions is given. Omega-limit sets are characterized for Riemann integrable derivatives and derivatiyes which are continuous almost everywhere. Techniques used in the investigation and formulation of results include finding theorems which relate the rather disparate notions of dynamical properties and generalized continuity. In addition to dynamical systems, numerous other applications of generalized continuity are imoestigated. Techniques used include application of the Baire Category Theorem and the notion of semi-closure. For example, results are formulated concerning functions determined by dense sets, including separately continuous functions, thus generalizing the classical result for continuous functions on dense subsets of the domain. The uniform boundedness theorem is extended to functions which are not necessarily continuous, including various derivatives. The closed graph theorem is strictly generalized in two separate ways, and applications are presented using these generalizations. An invariance property of separately continuous functions is given. Cluster sets are studied in connection with separate continuity, and various results are presented concerning locally bounded functions.
- Full Text:
- Date Issued: 2002
Convergence of old and new: a case study analysis of the development online by a South African radio station: Radiosondergrense/www.rsg.co.za
- Authors: Vasques, Vanessa Claudia
- Date: 2002
- Subjects: Radio stations -- South Africa , Radio stations -- South Africa -- Marketing , Radio stations -- Computer network resources , Radiosondergrense
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3498 , http://hdl.handle.net/10962/d1003913 , Radio stations -- South Africa , Radio stations -- South Africa -- Marketing , Radio stations -- Computer network resources , Radiosondergrense
- Description: This thesis is a case study analysis of the dream one radio station had about creating something new and unique on the Internet. RadioSonderGrense (RSG), an Afrikaans South African radio station, saw opportunities for themselves as a radio station on the Internet and put enormous resources and man-power into their venture. Their vision of what the Internet could bring to their radio station, and what they could bring to a website set the ground for creative and innovative thought. This dissertation is an examination of whether the Internet lived up to the expectations RSG had for it, and whether they were able to use their resources (in terms of their audience, their advertisers and the uniqueness of radio) to create something new and never seen before. The foremost aim of this dissertation is to shed some light onto the up-to-now under researched area of why radio stations have begun to develop on the Internet. Through the analysis of RSG, their comes to this subject some new thoughts and ideas about the convergence of these two mediums. RSG, and radio in general, are examined historically, practically and in comparison to the Internet. This is done in order to fully grasp the project that RSG had set for themselves and to realize where they had come from and where they hoped to go. It is argued that although RSG had hoped for great things, their innovative thought was not enough to guarantee them their dreams. They were not able to fully utilize the resources available to them in combination with what the Internet could offer them to fulfill the expectations they had for themselves. The foremost conclusion is that although RSG were able to envisage what the Internet could add to the radio station, they fell short of giving their listeners, users and advertisers a tool which could make the RSG website truly unique. Their website gives the user some interesting and useful applications, but it does not make full use of what the Internet and radio together could create.
- Full Text:
- Date Issued: 2002
- Authors: Vasques, Vanessa Claudia
- Date: 2002
- Subjects: Radio stations -- South Africa , Radio stations -- South Africa -- Marketing , Radio stations -- Computer network resources , Radiosondergrense
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3498 , http://hdl.handle.net/10962/d1003913 , Radio stations -- South Africa , Radio stations -- South Africa -- Marketing , Radio stations -- Computer network resources , Radiosondergrense
- Description: This thesis is a case study analysis of the dream one radio station had about creating something new and unique on the Internet. RadioSonderGrense (RSG), an Afrikaans South African radio station, saw opportunities for themselves as a radio station on the Internet and put enormous resources and man-power into their venture. Their vision of what the Internet could bring to their radio station, and what they could bring to a website set the ground for creative and innovative thought. This dissertation is an examination of whether the Internet lived up to the expectations RSG had for it, and whether they were able to use their resources (in terms of their audience, their advertisers and the uniqueness of radio) to create something new and never seen before. The foremost aim of this dissertation is to shed some light onto the up-to-now under researched area of why radio stations have begun to develop on the Internet. Through the analysis of RSG, their comes to this subject some new thoughts and ideas about the convergence of these two mediums. RSG, and radio in general, are examined historically, practically and in comparison to the Internet. This is done in order to fully grasp the project that RSG had set for themselves and to realize where they had come from and where they hoped to go. It is argued that although RSG had hoped for great things, their innovative thought was not enough to guarantee them their dreams. They were not able to fully utilize the resources available to them in combination with what the Internet could offer them to fulfill the expectations they had for themselves. The foremost conclusion is that although RSG were able to envisage what the Internet could add to the radio station, they fell short of giving their listeners, users and advertisers a tool which could make the RSG website truly unique. Their website gives the user some interesting and useful applications, but it does not make full use of what the Internet and radio together could create.
- Full Text:
- Date Issued: 2002
Counter-hair/gemonies: hair as a site of black identity struggle in post-apartheid South Africa
- Authors: Morey, Yvette Vivienne
- Date: 2002
- Subjects: Hairstyles -- South Africa , Women, Black -- Race identity , Hair -- Social aspects -- South Africa , Beauty, Personal -- Social aspects -- South Africa , Hairdressing of Black people
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3024 , http://hdl.handle.net/10962/d1002533 , Hairstyles -- South Africa , Women, Black -- Race identity , Hair -- Social aspects -- South Africa , Beauty, Personal -- Social aspects -- South Africa , Hairdressing of Black people
- Description: This thesis aims to allow the meanings engendered by various black hairstyle choices to emerge as discursive texts with which to further explore issues of black identity in post-apartheid South Africa. It seeks to identify what, if any, new discursive spaces and possibilities are operational in the post-apartheid capitalist context, and how identities are moulded by, and in tum, influence these possibilities. Operating within a discourse analytic approach, this research did not intend to establish fixed and generalisable notions of identity, but by unpacking the discursive baggage attached to historically loaded subjectivities it is concerned with reflecting identity as an ongoing and reflexive project. Entailing a diverse selection of texts, the analysis includes self-generated texts (stemming from interviews, a focus group and participant observation), and public domain texts (stemming from online and print media articles). Chapters 5 - 9 constitute the textual analysis. Using a consumer hair care product as a text, chapter 5 serves as an introduction to discourses surrounding black hair as a variously constructed object. This focus is concerned, more specifically, with the construction of black hair as a 'natural' object in chapter 6. Chapter 7 examines black hair gemonies and the " problematic classification and de/classification of class and consumer identities. Discourses pertaining to the construction and positioning of gendered and sexual subjectivities are explored in chapter 8. Finally, chapter 9 is concerned with the operations of discourses as they function to construct essentialised or hybrid conceptions of identity. The implications for black identity construction in post-apartheid South Africa are discussed in chapter 10 alongside a deconstruction of the research method and researcher positioning.
- Full Text:
- Date Issued: 2002
- Authors: Morey, Yvette Vivienne
- Date: 2002
- Subjects: Hairstyles -- South Africa , Women, Black -- Race identity , Hair -- Social aspects -- South Africa , Beauty, Personal -- Social aspects -- South Africa , Hairdressing of Black people
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3024 , http://hdl.handle.net/10962/d1002533 , Hairstyles -- South Africa , Women, Black -- Race identity , Hair -- Social aspects -- South Africa , Beauty, Personal -- Social aspects -- South Africa , Hairdressing of Black people
- Description: This thesis aims to allow the meanings engendered by various black hairstyle choices to emerge as discursive texts with which to further explore issues of black identity in post-apartheid South Africa. It seeks to identify what, if any, new discursive spaces and possibilities are operational in the post-apartheid capitalist context, and how identities are moulded by, and in tum, influence these possibilities. Operating within a discourse analytic approach, this research did not intend to establish fixed and generalisable notions of identity, but by unpacking the discursive baggage attached to historically loaded subjectivities it is concerned with reflecting identity as an ongoing and reflexive project. Entailing a diverse selection of texts, the analysis includes self-generated texts (stemming from interviews, a focus group and participant observation), and public domain texts (stemming from online and print media articles). Chapters 5 - 9 constitute the textual analysis. Using a consumer hair care product as a text, chapter 5 serves as an introduction to discourses surrounding black hair as a variously constructed object. This focus is concerned, more specifically, with the construction of black hair as a 'natural' object in chapter 6. Chapter 7 examines black hair gemonies and the " problematic classification and de/classification of class and consumer identities. Discourses pertaining to the construction and positioning of gendered and sexual subjectivities are explored in chapter 8. Finally, chapter 9 is concerned with the operations of discourses as they function to construct essentialised or hybrid conceptions of identity. The implications for black identity construction in post-apartheid South Africa are discussed in chapter 10 alongside a deconstruction of the research method and researcher positioning.
- Full Text:
- Date Issued: 2002
Critical literacy in South Africa : possibilities and constraints in 2002
- Authors: Prinsloo, Jeanne , Janks, H
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6330 , http://hdl.handle.net/10962/d1008475
- Description: This article examines the Curriculum documents produced in South Africa since the election of a democratic government in 1994 in order to consider the possibilities they create for the inclusion of critical literacy in the teaching of home languages. This discussion is set against an analysis of the apartheid curriculum documents prior to 1994 and a consideration of the ongoing inequalities in the provision of human and material resources across the system. Despite real constraints with regard to implementation, it is argued that the new Curriculum effects a significant break with the past and makes a positive contribution to transforming language education.
- Full Text:
- Date Issued: 2002
- Authors: Prinsloo, Jeanne , Janks, H
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6330 , http://hdl.handle.net/10962/d1008475
- Description: This article examines the Curriculum documents produced in South Africa since the election of a democratic government in 1994 in order to consider the possibilities they create for the inclusion of critical literacy in the teaching of home languages. This discussion is set against an analysis of the apartheid curriculum documents prior to 1994 and a consideration of the ongoing inequalities in the provision of human and material resources across the system. Despite real constraints with regard to implementation, it is argued that the new Curriculum effects a significant break with the past and makes a positive contribution to transforming language education.
- Full Text:
- Date Issued: 2002
Curriculum patterning in environmental education: A review of developments in formal education in South Africa
- Authors: Lotz-Sisitka, Heila
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/437280 , vital:73365 , ISBN 978-07969-2001-0 , https://www.hsrcpress.ac.za/books/environmental-education-ethics-action-in-southern-africa
- Description: Written by environmental practitioners from across the region, the Monograph is a window onto envi-ronmental challenges in a diversity of African con-texts. These contexts include Malawian officials and community leaders, new to multi-level governance, taking up the challenge of environmental manage-ment in villages and districts; Ugandan small-scale farmers in partnership with NGOs trying to produce sustainably for the household and the international market; and government-civil society partnerships in South Africa, where the political transformation of the education system introduced a focus on envi-ronment and human rights in the national school curriculum.
- Full Text:
- Date Issued: 2002
- Authors: Lotz-Sisitka, Heila
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/437280 , vital:73365 , ISBN 978-07969-2001-0 , https://www.hsrcpress.ac.za/books/environmental-education-ethics-action-in-southern-africa
- Description: Written by environmental practitioners from across the region, the Monograph is a window onto envi-ronmental challenges in a diversity of African con-texts. These contexts include Malawian officials and community leaders, new to multi-level governance, taking up the challenge of environmental manage-ment in villages and districts; Ugandan small-scale farmers in partnership with NGOs trying to produce sustainably for the household and the international market; and government-civil society partnerships in South Africa, where the political transformation of the education system introduced a focus on envi-ronment and human rights in the national school curriculum.
- Full Text:
- Date Issued: 2002
Cyclic voltammetric studies of octabutylthiophthalo-cyaninato-cobalt (II) and its self-assembled monolayer (SAM) on gold electrode
- Ozoemena, Kenneth, Westbroek, Philippe, Nyokong, Tebello
- Authors: Ozoemena, Kenneth , Westbroek, Philippe , Nyokong, Tebello
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/289567 , vital:56650 , xlink:href="https://doi.org/10.1142/S1088424602000130"
- Description: The synthesis of thiol-derivatized cobalt phthalocyanine complex, 2,3,9,10,16,17,23,24-octa (butylthiophthalocyaninatocobalt(II) (CoOBTPc) is described. Cyclic voltammetric data of this complex in DMF showed five quasi-reversible and reversible, diffusion-controlled redox couples, comprising both the phthalocyanine ring and central metal redox processes. The CoOBTPc complex forms a self-assembled monolayer (SAM) on gold electrode. The investigation of the integrity of this SAM, using the established cyclic voltammetric methods in aqueous alkaline solutions, gave evidence about the formation of a stable and easily reproducible monolayer. However, due to its susceptibility to destruction via oxidative and reductive desorptions, its potential application as an electrochemical sensor in alkaline pH is limited to a potential window of between −0.20 and +0.55 V vs Ag/AgCl.
- Full Text:
- Date Issued: 2002
- Authors: Ozoemena, Kenneth , Westbroek, Philippe , Nyokong, Tebello
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/289567 , vital:56650 , xlink:href="https://doi.org/10.1142/S1088424602000130"
- Description: The synthesis of thiol-derivatized cobalt phthalocyanine complex, 2,3,9,10,16,17,23,24-octa (butylthiophthalocyaninatocobalt(II) (CoOBTPc) is described. Cyclic voltammetric data of this complex in DMF showed five quasi-reversible and reversible, diffusion-controlled redox couples, comprising both the phthalocyanine ring and central metal redox processes. The CoOBTPc complex forms a self-assembled monolayer (SAM) on gold electrode. The investigation of the integrity of this SAM, using the established cyclic voltammetric methods in aqueous alkaline solutions, gave evidence about the formation of a stable and easily reproducible monolayer. However, due to its susceptibility to destruction via oxidative and reductive desorptions, its potential application as an electrochemical sensor in alkaline pH is limited to a potential window of between −0.20 and +0.55 V vs Ag/AgCl.
- Full Text:
- Date Issued: 2002
De-scribing the Timaeus: a transgression of the (phal) logocentric convention that discourse has only one form, language
- Authors: Ord, Jennifer
- Date: 2002
- Subjects: Discourse analysis , Art -- Philosophy
- Language: English
- Type: Thesis , Masters , MTech (Fine Art)
- Identifier: vital:10763 , http://hdl.handle.net/10948/115 , Discourse analysis , Art -- Philosophy
- Description: Like writing, art making is primarily a means of human expression, a means of communication – both “allow us to categorize our (inner and outer) environment as represented by symbols” (Appignanesi, 1999: 7). Yet it is language in the traditional Western garb of rational, philosophical discourse that has been perceived as the primary means of manifesting knowledge and positing truth, not only regarding the character of human existence, but also the nature of art. This infers the acceptance of both works as literally “truth of things”, and of “a language of reason” that “perfectly represents the real world” (Appignanesi, 1999: 77). Going against the grain of this traditional bias, Jacques Derrida holds that, firstly, “human knowledge is not as controllable or as cogent as Western thinkers would have it”: secondly, that language functions in “subtle and often contradictory ways” thus rendering certainty, truth, and perfect representation ever elusive to us (Lye, 1997: 2); and, thirdly, that “practices of interpretation which include art but are not limited to language, are extended discourses” (Appignanesi, 1999: 79). So, the “work of reason” (or rationalism) in this sense, is no longer the definitive “voice” of authority when it comes to ascribing meaning, proclaiming a message, defining truth, etc. Having the grip of its authority loosened and thus its rigid, imposing borders opened up, the communication of knowledge as a form of “aesthetic fiction” (Megill, 1987: 265) is allowed entry into the rarefied field of philosophical discourse. Moreover, if visual art (one such “aesthetic fiction”) is a process of sign-making, as is written and spoken language; if it therefore constitutes a signifying system, as does written and spoken language (Bal and Bryson in Preziosi, 1998: 242); and, if art is not just about autonomous, in-house formalism, then can it not, in any case, validly offer a form for discourse, albeit a different kind of discourse, a discourse that is not “truth seeking” (Sim, 1992: 33)? Here, the maker of the proposed artwork-asdiscourse would not be attempting to establish the truth or falsity of a philosophical position, but, as Derrida would have it, create a form which, without mimicry, would evocatively allude to Plato, his “deconstructor” and the maker of the proposed artwork. Discourse in this sense, then, would generate “active interpretation… infinite free association” (Megill, 1987: 283), because, as in Derrida’s writing, interpretation no longer aims at “the reconciliation or unification of warring truths (Sim, 1992: 10); in other words, it breaks with the (phal)logocentric tradition of discourse as dialectical and becomes questioning without closure. For visual art to enter the exalted arena of philosophical discourse, it cannot be selfreflexive in the Greenbergian or formalist sense – it has to be about something philosophical and this ‘something’ will be a deconstructive response to Plato’s doctrine of the two worlds in the Timaeus. What I propose presenting, then, is an imagographic rather than (phal)logocentric exposition of philosophical content where the aim is not to shape a certainty or to infer an absolute presence or essence of anything, but rather to suggest traces of the maker of the artwork reading Derrida, reading Plato. The proposed artwork as a response to texts will thus be a “pre-text” of my own endeavour.
- Full Text:
- Date Issued: 2002
- Authors: Ord, Jennifer
- Date: 2002
- Subjects: Discourse analysis , Art -- Philosophy
- Language: English
- Type: Thesis , Masters , MTech (Fine Art)
- Identifier: vital:10763 , http://hdl.handle.net/10948/115 , Discourse analysis , Art -- Philosophy
- Description: Like writing, art making is primarily a means of human expression, a means of communication – both “allow us to categorize our (inner and outer) environment as represented by symbols” (Appignanesi, 1999: 7). Yet it is language in the traditional Western garb of rational, philosophical discourse that has been perceived as the primary means of manifesting knowledge and positing truth, not only regarding the character of human existence, but also the nature of art. This infers the acceptance of both works as literally “truth of things”, and of “a language of reason” that “perfectly represents the real world” (Appignanesi, 1999: 77). Going against the grain of this traditional bias, Jacques Derrida holds that, firstly, “human knowledge is not as controllable or as cogent as Western thinkers would have it”: secondly, that language functions in “subtle and often contradictory ways” thus rendering certainty, truth, and perfect representation ever elusive to us (Lye, 1997: 2); and, thirdly, that “practices of interpretation which include art but are not limited to language, are extended discourses” (Appignanesi, 1999: 79). So, the “work of reason” (or rationalism) in this sense, is no longer the definitive “voice” of authority when it comes to ascribing meaning, proclaiming a message, defining truth, etc. Having the grip of its authority loosened and thus its rigid, imposing borders opened up, the communication of knowledge as a form of “aesthetic fiction” (Megill, 1987: 265) is allowed entry into the rarefied field of philosophical discourse. Moreover, if visual art (one such “aesthetic fiction”) is a process of sign-making, as is written and spoken language; if it therefore constitutes a signifying system, as does written and spoken language (Bal and Bryson in Preziosi, 1998: 242); and, if art is not just about autonomous, in-house formalism, then can it not, in any case, validly offer a form for discourse, albeit a different kind of discourse, a discourse that is not “truth seeking” (Sim, 1992: 33)? Here, the maker of the proposed artwork-asdiscourse would not be attempting to establish the truth or falsity of a philosophical position, but, as Derrida would have it, create a form which, without mimicry, would evocatively allude to Plato, his “deconstructor” and the maker of the proposed artwork. Discourse in this sense, then, would generate “active interpretation… infinite free association” (Megill, 1987: 283), because, as in Derrida’s writing, interpretation no longer aims at “the reconciliation or unification of warring truths (Sim, 1992: 10); in other words, it breaks with the (phal)logocentric tradition of discourse as dialectical and becomes questioning without closure. For visual art to enter the exalted arena of philosophical discourse, it cannot be selfreflexive in the Greenbergian or formalist sense – it has to be about something philosophical and this ‘something’ will be a deconstructive response to Plato’s doctrine of the two worlds in the Timaeus. What I propose presenting, then, is an imagographic rather than (phal)logocentric exposition of philosophical content where the aim is not to shape a certainty or to infer an absolute presence or essence of anything, but rather to suggest traces of the maker of the artwork reading Derrida, reading Plato. The proposed artwork as a response to texts will thus be a “pre-text” of my own endeavour.
- Full Text:
- Date Issued: 2002
Deconstructive discourse analysis: extending the methodological conversation
- Authors: Macleod, Catriona I
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6259 , http://hdl.handle.net/10962/d1007877 , http://journals.sagepub.com/doi/abs/10.1177/008124630203200103
- Description: Discourse analysis is increasingly becoming a methodology of preference amongst qualitative researchers. There is a danger, however, of it being viewed as a bounded and uncontested domain of research practice. As discourse analysis is inextricably linked with theoretical issues, it is a dynamic practice that is constantly in a process of revision. In this paper I reflect on some of the conceptualisations undergirding the notion of discourse – conceptualisations that have important implications in terms of how the practice of discourse analysis proceeds. I highlight some of the dualisms that may plague discourse analysis, and offer some solutions to these. Finally, I outline the deconstructive discourse analysis that I utilised in my doctoral work. The purpose of the latter is not to provide a recipe of methodology, but to illustrate how elements of various theorists’ work (in this case Foucault, Derrida and Parker) may be profitably drawn together to perform specific discourse analytic work. , Rhodes University
- Full Text:
- Date Issued: 2002
- Authors: Macleod, Catriona I
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6259 , http://hdl.handle.net/10962/d1007877 , http://journals.sagepub.com/doi/abs/10.1177/008124630203200103
- Description: Discourse analysis is increasingly becoming a methodology of preference amongst qualitative researchers. There is a danger, however, of it being viewed as a bounded and uncontested domain of research practice. As discourse analysis is inextricably linked with theoretical issues, it is a dynamic practice that is constantly in a process of revision. In this paper I reflect on some of the conceptualisations undergirding the notion of discourse – conceptualisations that have important implications in terms of how the practice of discourse analysis proceeds. I highlight some of the dualisms that may plague discourse analysis, and offer some solutions to these. Finally, I outline the deconstructive discourse analysis that I utilised in my doctoral work. The purpose of the latter is not to provide a recipe of methodology, but to illustrate how elements of various theorists’ work (in this case Foucault, Derrida and Parker) may be profitably drawn together to perform specific discourse analytic work. , Rhodes University
- Full Text:
- Date Issued: 2002
Design, development and analysis of the friction stir welding process
- Authors: Blignault, Calvin
- Date: 2002
- Subjects: Friction welding
- Language: English
- Type: Thesis , Masters , MTech (Mechanical Engineering)
- Identifier: vital:10809 , http://hdl.handle.net/10948/1350 , Friction welding
- Description: The development of a CNC-based technology FSW machine to accurately produce friction stir weld samples that can be analyzed for research purposes is implemented and discussed. A process diagnosis and control scheme to improve the process monitoring and weld evaluation capabilities of an FSW machine are proposed and implemented. Basic CNC-based hardware implementation such as optical encoders and inverters for process control are explained and verified. The control scheme and framework of interfaces to the digital I/O cards for PC user interface are explained. An advanced monitoring system which senses process performance parameters such as tool temperature, 3-axis tool forces, torque and spindle speed are explained. Mechanical designs and manufacturing techniques such as tool, clamp and backing plate designs are explained and verified. The process parameters for quality optimization are investigated and optimized by making use of Correlation and Regression Analysis. The statistical data and analytical relationships between welding parameters (independent) and each of the performance parameters (dependent) are obtained and used to simulate the machining process. The weld research samples are tested for strength and integrity making use of various scientific testing techniques. The reliability of the samples are also evaluated and compared to that of other institutions. Process variables and the optimum operating range of the Friction Stir Welding machine is determined and a framework for further research into weld quality optimization is set.
- Full Text:
- Date Issued: 2002
- Authors: Blignault, Calvin
- Date: 2002
- Subjects: Friction welding
- Language: English
- Type: Thesis , Masters , MTech (Mechanical Engineering)
- Identifier: vital:10809 , http://hdl.handle.net/10948/1350 , Friction welding
- Description: The development of a CNC-based technology FSW machine to accurately produce friction stir weld samples that can be analyzed for research purposes is implemented and discussed. A process diagnosis and control scheme to improve the process monitoring and weld evaluation capabilities of an FSW machine are proposed and implemented. Basic CNC-based hardware implementation such as optical encoders and inverters for process control are explained and verified. The control scheme and framework of interfaces to the digital I/O cards for PC user interface are explained. An advanced monitoring system which senses process performance parameters such as tool temperature, 3-axis tool forces, torque and spindle speed are explained. Mechanical designs and manufacturing techniques such as tool, clamp and backing plate designs are explained and verified. The process parameters for quality optimization are investigated and optimized by making use of Correlation and Regression Analysis. The statistical data and analytical relationships between welding parameters (independent) and each of the performance parameters (dependent) are obtained and used to simulate the machining process. The weld research samples are tested for strength and integrity making use of various scientific testing techniques. The reliability of the samples are also evaluated and compared to that of other institutions. Process variables and the optimum operating range of the Friction Stir Welding machine is determined and a framework for further research into weld quality optimization is set.
- Full Text:
- Date Issued: 2002
Design, evaluation and comparison of evolution and reinforcement learning models
- Authors: Mclean, Clinton Brett
- Date: 2002
- Subjects: Evolutionary computation Neural networks (Computer science) Reinforcement learning
- Language: English
- Type: Thesis , Masters , MEcon
- Identifier: vital:4625 , http://hdl.handle.net/10962/d1006493
- Description: This work presents the design, evaluation and comparison of evolution and reinforcement learning models, in isolation and combined in Darwinian and Lamarckian frameworks, with a particular emphasis being placed on their adaptive nature in response to environments that become increasingly unstable. Our ultimate objective is to determine whether hybrid models of evolution and learning can demonstrate adaptive qualities beyond those of such models when applied in isolation. This work demonstrates the limitations of evolution, reinforcement learning and Lamarckian models in dealing with increasingly unstable environments, while noting the effective adaptive nature of a Darwinian model to assimilate increasing levels of instability. This is shown to be a result of the Darwinian evolution model's ability to separate learning at two levels, the population's experience of the environment over the course of many generations and the individual's experience of the environment over the course of its lifetime. Thus, knowledge relating to the general characteristics of the environment over many generations can be maintained in the population's genotypes with phenotype (reinforcement) learning being utilized to adapt a particular agent to the particular characteristics of its environment. Lamarckian evolution, though, is shown to demonstrate adaptive characteristics that are highly effective in response to the stable environments. Selection and reproduction combined with reinforcement learning creates a model that has the ability to utilize useful knowledge produced by reinforcements, as opposed to random mutations, to accelerate the search process. As a result the influence of individual learning on the populations evolution is shown to be more successful when applied in the more direct Lamarckian form. Based on our results demonstrating the success of Lamarckian strategies in stable environments and Darwinian strategies in unstable environments, hybrid Darwinian/Lamarckian models are created with a view towards combining the advantages of both forms of evolution to produce a superior adaptive capability. Our investigation demonstrates that such hybrid models can effectively combine the adaptive advantageous of both Darwinian and Lamarckian evolution to provide a more effective capability of adapting to a range of conditions, from stable to unstable, appropriately adjusting the required degree of inheritance in response to the requirements of the environment.
- Full Text:
- Date Issued: 2002
- Authors: Mclean, Clinton Brett
- Date: 2002
- Subjects: Evolutionary computation Neural networks (Computer science) Reinforcement learning
- Language: English
- Type: Thesis , Masters , MEcon
- Identifier: vital:4625 , http://hdl.handle.net/10962/d1006493
- Description: This work presents the design, evaluation and comparison of evolution and reinforcement learning models, in isolation and combined in Darwinian and Lamarckian frameworks, with a particular emphasis being placed on their adaptive nature in response to environments that become increasingly unstable. Our ultimate objective is to determine whether hybrid models of evolution and learning can demonstrate adaptive qualities beyond those of such models when applied in isolation. This work demonstrates the limitations of evolution, reinforcement learning and Lamarckian models in dealing with increasingly unstable environments, while noting the effective adaptive nature of a Darwinian model to assimilate increasing levels of instability. This is shown to be a result of the Darwinian evolution model's ability to separate learning at two levels, the population's experience of the environment over the course of many generations and the individual's experience of the environment over the course of its lifetime. Thus, knowledge relating to the general characteristics of the environment over many generations can be maintained in the population's genotypes with phenotype (reinforcement) learning being utilized to adapt a particular agent to the particular characteristics of its environment. Lamarckian evolution, though, is shown to demonstrate adaptive characteristics that are highly effective in response to the stable environments. Selection and reproduction combined with reinforcement learning creates a model that has the ability to utilize useful knowledge produced by reinforcements, as opposed to random mutations, to accelerate the search process. As a result the influence of individual learning on the populations evolution is shown to be more successful when applied in the more direct Lamarckian form. Based on our results demonstrating the success of Lamarckian strategies in stable environments and Darwinian strategies in unstable environments, hybrid Darwinian/Lamarckian models are created with a view towards combining the advantages of both forms of evolution to produce a superior adaptive capability. Our investigation demonstrates that such hybrid models can effectively combine the adaptive advantageous of both Darwinian and Lamarckian evolution to provide a more effective capability of adapting to a range of conditions, from stable to unstable, appropriately adjusting the required degree of inheritance in response to the requirements of the environment.
- Full Text:
- Date Issued: 2002
Detection of neurotransmitters using metallophthalocyanines as electrocatalysts
- Authors: Oni, Joshua Idowu
- Date: 2002
- Subjects: Neurotransmitters Electrochemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4435 , http://hdl.handle.net/10962/d1007470
- Description: Some metallophthalocyanine complexes were synthesized and their catalytic activities towards the detection and quantification of the neurotransmitters dopamine, serotonin and histamine were investigated. The study of the possible interaction between these transmitter substances and the metallophthalocyanine complexes was undertaken. Dopamine, serotonin and histamine formed complexes with Iron (II) tetrasulfophthalocyanine. The rate and equilibrium constants obtained for the coordination are in the range of values reported in the literature for ligand coordination to iron phthalocyanine complexes. Carbon paste electrodes of millimetric diameters modified with Iron (II) tetrasulfophthalocyanine exhibited good electro catalytic activity towards the detection and analysis of dopamine and serotonin while at the same time eliminated the problem of interference posed by ascorbic acid in the electrochemical analysis of neurotransmitters. A detection limit of the order of 10-6 mol dm-3 was obtained for both dopamine and serotonin at the modified electrodes. Carbon paste ultra micro electrodes modified with iron (II) tetrasulfophthalocyanine were also used for the detection of dopamine and serotonin as well as the simultaneous determination of dopamine and ascorbic acid in a mixture. The detection limit obtained for dopamine at the ultra microelectrode was 4.2xlO-7 mol dm-3 The electrode kinetics of vitamin BI as well as the stability of the electrode towards its determination was improved upon by modifying carbon paste electrodes with manganese phthalocyanine. The modified electrodes were used for the analysis of vitamin BI in tablets.
- Full Text:
- Date Issued: 2002
- Authors: Oni, Joshua Idowu
- Date: 2002
- Subjects: Neurotransmitters Electrochemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4435 , http://hdl.handle.net/10962/d1007470
- Description: Some metallophthalocyanine complexes were synthesized and their catalytic activities towards the detection and quantification of the neurotransmitters dopamine, serotonin and histamine were investigated. The study of the possible interaction between these transmitter substances and the metallophthalocyanine complexes was undertaken. Dopamine, serotonin and histamine formed complexes with Iron (II) tetrasulfophthalocyanine. The rate and equilibrium constants obtained for the coordination are in the range of values reported in the literature for ligand coordination to iron phthalocyanine complexes. Carbon paste electrodes of millimetric diameters modified with Iron (II) tetrasulfophthalocyanine exhibited good electro catalytic activity towards the detection and analysis of dopamine and serotonin while at the same time eliminated the problem of interference posed by ascorbic acid in the electrochemical analysis of neurotransmitters. A detection limit of the order of 10-6 mol dm-3 was obtained for both dopamine and serotonin at the modified electrodes. Carbon paste ultra micro electrodes modified with iron (II) tetrasulfophthalocyanine were also used for the detection of dopamine and serotonin as well as the simultaneous determination of dopamine and ascorbic acid in a mixture. The detection limit obtained for dopamine at the ultra microelectrode was 4.2xlO-7 mol dm-3 The electrode kinetics of vitamin BI as well as the stability of the electrode towards its determination was improved upon by modifying carbon paste electrodes with manganese phthalocyanine. The modified electrodes were used for the analysis of vitamin BI in tablets.
- Full Text:
- Date Issued: 2002