Symmetrically and unsymmetrically substituted carboxy phthalocyanines as sensitizers for nanoporous ZnO films
- Masilela, Nkosiphile, Nombona, Nolwazi, Loewenstein, Thomas, Nyokong, Tebello, Schlettwein, Derck
- Authors: Masilela, Nkosiphile , Nombona, Nolwazi , Loewenstein, Thomas , Nyokong, Tebello , Schlettwein, Derck
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/249126 , vital:51780 , xlink:href="https://doi.org/10.1142/S1088424610002793"
- Description: The photoelectroectrochemical studies of water soluble octacarboxylated oxotitanium (OTiOCPc), zinc (ZnOCPC), hydroxyaluminium ((OH)AlOCPc), dihydroxysilicon ((OH)2SiOCPc), hydroxygallium (OHGaOCPc) and low symmetry zinc monocarboxy (ZnMCPc) phthalocyanines were performed. The dyes were adsorbed to nanoporous ZnO electrodeposited in the presence of eosin Y as structure directing agent (SDA) on FTO substrates by refluxing or soaking the films in a solution containing the dye of interest such that a full surface coverage was achieved. High external (IPCE) and internal (APCE) quantum efficiencies of up to 50.6% and 96.7% were achieved for the OTiOCPc complex. There was a lower overall cell efficiency for cells sensitized with phthalocyanines containing hydroxyl as axial ligand ZnO/(OH)2SiOCPc, ZnO/(OH)GaOCPc and (OH)AlOCPc because of strong aggregation on the surface of the electrodes. To further suppress dye aggregation, the zinc complex of a new monocarboxylated phthalocyanine sensitizer with bulky naphtho side groups (ZnMCPc) was employed. Among the studied sensitizers, ZnMCPc gave the highest overall cell efficiency of phthalocyanine electrodeposited on ZnO of η = 0.48%.
- Full Text:
- Authors: Masilela, Nkosiphile , Nombona, Nolwazi , Loewenstein, Thomas , Nyokong, Tebello , Schlettwein, Derck
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/249126 , vital:51780 , xlink:href="https://doi.org/10.1142/S1088424610002793"
- Description: The photoelectroectrochemical studies of water soluble octacarboxylated oxotitanium (OTiOCPc), zinc (ZnOCPC), hydroxyaluminium ((OH)AlOCPc), dihydroxysilicon ((OH)2SiOCPc), hydroxygallium (OHGaOCPc) and low symmetry zinc monocarboxy (ZnMCPc) phthalocyanines were performed. The dyes were adsorbed to nanoporous ZnO electrodeposited in the presence of eosin Y as structure directing agent (SDA) on FTO substrates by refluxing or soaking the films in a solution containing the dye of interest such that a full surface coverage was achieved. High external (IPCE) and internal (APCE) quantum efficiencies of up to 50.6% and 96.7% were achieved for the OTiOCPc complex. There was a lower overall cell efficiency for cells sensitized with phthalocyanines containing hydroxyl as axial ligand ZnO/(OH)2SiOCPc, ZnO/(OH)GaOCPc and (OH)AlOCPc because of strong aggregation on the surface of the electrodes. To further suppress dye aggregation, the zinc complex of a new monocarboxylated phthalocyanine sensitizer with bulky naphtho side groups (ZnMCPc) was employed. Among the studied sensitizers, ZnMCPc gave the highest overall cell efficiency of phthalocyanine electrodeposited on ZnO of η = 0.48%.
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Syntheses and investigation of the effects of position and nature of substituent on the spectral, electrochemical and spectroelectrochemical properties of new cobalt phthalocyanine complexes
- Akinbulu, Isaac A, Nyokong, Tebello
- Authors: Akinbulu, Isaac A , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/261677 , vital:53434 , xlink:href="https://doi.org/10.1016/j.poly.2010.01.004"
- Description: The syntheses of new cobalt phthalocyanine (CoPc) complexes, tetra-substituted with diethylaminoethanethio at the peripheral (complex 3a) and non-peripheral (complex 3b) positions, and with benzylmercapto at the non-peripheral position (complex 5), are reported. The effects of the nature and position of substituent on the spectral, electrochemical and spectroelectrochemical properties of these complexes are investigated. Solution electrochemistry of complex 3a showed three distinctly resolved redox processes attributed to CoIIIPc−2/CoIIPc−2 (E½ = +0.64 V versus Ag|AgCl), CoIIPc−2/CoIPc−2 (E½ = −0.24 V versus Ag|AgCl) and CoIPc−2/CoIPc−3 (E½ = −1.26 V versus Ag|AgCl) species. No ring oxidation was observed in complex 3a. Complex 3b showed both ring-based oxidation, attributed to CoIIIPc−1/CoIIIPc−2 species (Ep = +0.86 V versus Ag|AgCl), and ring-based reduction associated with CoIPc−2/CoIPc−3 species (E½ = −1.46 V versus Ag|AgCl), with the normal metal-based redox processes in CoPc complexes: CoIIIPc−2/CoIIPc−2 (Ep = +0.41 V versus Ag|AgCl) and CoIIPc−2/CoIPc−2 (E½ = −0.38 V versus Ag|AgCl). Solution electrochemistry of complex 5 showed the same type and number of species observed in complex 3a: CoIIIPc−2/CoIIPc−2 (Ep = +0.59 V versus Ag|AgCl), CoIIPc−2/CoIPc−2 (E½ = −0.26 V versus Ag|AgCl) and CoIPc−2/CoIPc−3 (E½ = −1.39 V versus Ag|AgCl) species. These processes were confirmed using spectroelectrochemistry.
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- Authors: Akinbulu, Isaac A , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/261677 , vital:53434 , xlink:href="https://doi.org/10.1016/j.poly.2010.01.004"
- Description: The syntheses of new cobalt phthalocyanine (CoPc) complexes, tetra-substituted with diethylaminoethanethio at the peripheral (complex 3a) and non-peripheral (complex 3b) positions, and with benzylmercapto at the non-peripheral position (complex 5), are reported. The effects of the nature and position of substituent on the spectral, electrochemical and spectroelectrochemical properties of these complexes are investigated. Solution electrochemistry of complex 3a showed three distinctly resolved redox processes attributed to CoIIIPc−2/CoIIPc−2 (E½ = +0.64 V versus Ag|AgCl), CoIIPc−2/CoIPc−2 (E½ = −0.24 V versus Ag|AgCl) and CoIPc−2/CoIPc−3 (E½ = −1.26 V versus Ag|AgCl) species. No ring oxidation was observed in complex 3a. Complex 3b showed both ring-based oxidation, attributed to CoIIIPc−1/CoIIIPc−2 species (Ep = +0.86 V versus Ag|AgCl), and ring-based reduction associated with CoIPc−2/CoIPc−3 species (E½ = −1.46 V versus Ag|AgCl), with the normal metal-based redox processes in CoPc complexes: CoIIIPc−2/CoIIPc−2 (Ep = +0.41 V versus Ag|AgCl) and CoIIPc−2/CoIPc−2 (E½ = −0.38 V versus Ag|AgCl). Solution electrochemistry of complex 5 showed the same type and number of species observed in complex 3a: CoIIIPc−2/CoIIPc−2 (Ep = +0.59 V versus Ag|AgCl), CoIIPc−2/CoIPc−2 (E½ = −0.26 V versus Ag|AgCl) and CoIPc−2/CoIPc−3 (E½ = −1.39 V versus Ag|AgCl) species. These processes were confirmed using spectroelectrochemistry.
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Synthesis and electrochemical characterisation of new tantalum (V) alkythio phthalocyanines
- Chauke, Vongani, Nyokong, Tebello
- Authors: Chauke, Vongani , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/249093 , vital:51777 , xlink:href="https://doi.org/10.1016/j.ica.2010.05.003"
- Description: The synthesis and electrochemical characterisation of octa-pentylthio (4a) and octa-octylthio (4b) – phthalocyaninato tantalum (III) hydroxide are hereby reported. These TaPc complexes absorb in the near infrared region (∼800 nm in dichloromethane). They show good solubility in most common solvents especially non-viscous solvents such as dichloromethane and chloroform. NMR, mass and infrared spectroscopy and elemental analysis confirmed the structures and purity of the synthesised complexes. The cyclic voltammograms (CVs) showed reversible reduction couples and irreversible oxidation peaks. The latter exhibited adsorption behavior. The reduction processes were observed at −0.74 and −1.13 V (versus Ag|AgCl) for 4a, and −0.67, −1.02 and −1.48 V (versus Ag|AgCl) for 4b. Spectroelectrochemistry confirmed one metal reduction, with the rest of the redox processes being centered on the phthalocyanine ring.
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- Authors: Chauke, Vongani , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/249093 , vital:51777 , xlink:href="https://doi.org/10.1016/j.ica.2010.05.003"
- Description: The synthesis and electrochemical characterisation of octa-pentylthio (4a) and octa-octylthio (4b) – phthalocyaninato tantalum (III) hydroxide are hereby reported. These TaPc complexes absorb in the near infrared region (∼800 nm in dichloromethane). They show good solubility in most common solvents especially non-viscous solvents such as dichloromethane and chloroform. NMR, mass and infrared spectroscopy and elemental analysis confirmed the structures and purity of the synthesised complexes. The cyclic voltammograms (CVs) showed reversible reduction couples and irreversible oxidation peaks. The latter exhibited adsorption behavior. The reduction processes were observed at −0.74 and −1.13 V (versus Ag|AgCl) for 4a, and −0.67, −1.02 and −1.48 V (versus Ag|AgCl) for 4b. Spectroelectrochemistry confirmed one metal reduction, with the rest of the redox processes being centered on the phthalocyanine ring.
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Synthesis and photophysical properties of 1, 1′-binaphthol substituted phthalocyanines
- Canlica, Meylude, Nyokong, Tebello
- Authors: Canlica, Meylude , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/249148 , vital:51782 , xlink:href="https://doi.org/10.1016/j.ica.2010.06.034"
- Description: We report on the synthesis, characterization and photophysical properties of a new symmetrically tetra substituted {at non-peripheral positions with tetra(1,1′-bi-binaphtoxy)} phthalocyanines containing H2, Mg(II), Al(III)Cl, Si(IV)Cl2 in the central cavity. The synthesized compounds were characterized by the elemental analyses, UV–Vis, FT-IR and 1H NMR spectroscopies. The fluorescence quantum yields, triplet quantum yields and lifetimes of the newly synthesized H2, Mg, Al, and Si phthalocyanines were explored. Triplet quantum yields ranged from 0.24 to 0.54. The triplet lifetime for the silicon phthalocyanine derivative was the highest ever reported for a phthalocyanine (∼3.5 ms).
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- Authors: Canlica, Meylude , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/249148 , vital:51782 , xlink:href="https://doi.org/10.1016/j.ica.2010.06.034"
- Description: We report on the synthesis, characterization and photophysical properties of a new symmetrically tetra substituted {at non-peripheral positions with tetra(1,1′-bi-binaphtoxy)} phthalocyanines containing H2, Mg(II), Al(III)Cl, Si(IV)Cl2 in the central cavity. The synthesized compounds were characterized by the elemental analyses, UV–Vis, FT-IR and 1H NMR spectroscopies. The fluorescence quantum yields, triplet quantum yields and lifetimes of the newly synthesized H2, Mg, Al, and Si phthalocyanines were explored. Triplet quantum yields ranged from 0.24 to 0.54. The triplet lifetime for the silicon phthalocyanine derivative was the highest ever reported for a phthalocyanine (∼3.5 ms).
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Synthetic pathways to water-soluble phthalocyanines and close analogs
- Dumoulin, Fabienne, Durmus, Mahmut, Ahsen, Vefa, Nyokong, Tebello
- Authors: Dumoulin, Fabienne , Durmus, Mahmut , Ahsen, Vefa , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/249082 , vital:51776 , xlink:href="https://doi.org/10.1016/j.ccr.2010.05.002"
- Description: The different types of water-soluble phthalocyanines are presented and their synthesis is reviewed.
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- Authors: Dumoulin, Fabienne , Durmus, Mahmut , Ahsen, Vefa , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/249082 , vital:51776 , xlink:href="https://doi.org/10.1016/j.ccr.2010.05.002"
- Description: The different types of water-soluble phthalocyanines are presented and their synthesis is reviewed.
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Teaching conflict-sensitive journalism:
- Authors: du Toit, Peter
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159449 , vital:40298 , https://hdl.handle.net/10520/EJC139358
- Description: We expect court reporters to know something about the law, financial journalists to have a grounding in economics, and parliamentary correspondents to understand politics, but many journalists are ill-equipped handle social phenomenon that is ubiquitous to most beats - conflict.
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- Authors: du Toit, Peter
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159449 , vital:40298 , https://hdl.handle.net/10520/EJC139358
- Description: We expect court reporters to know something about the law, financial journalists to have a grounding in economics, and parliamentary correspondents to understand politics, but many journalists are ill-equipped handle social phenomenon that is ubiquitous to most beats - conflict.
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Teaching journalism to produce “interpretive communities" rather than just “professionals”:
- Authors: Garman, Anthea
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159846 , vital:40349 , DOI: 10.1080/02560054.2005.9653330
- Description: Debates about whether journalism is a “trade” and can only be learnt “on the job”, or whether journalism should even be taught at universities, are no longer fruitful or even interesting for teachers in tertiary environments. The far more important discussion around the teaching of journalism should be on the approach which focuses too exclusively on its nature as a “profession” and so ignores the critical function of journalists in the world as “interpretive communities”.
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- Authors: Garman, Anthea
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159846 , vital:40349 , DOI: 10.1080/02560054.2005.9653330
- Description: Debates about whether journalism is a “trade” and can only be learnt “on the job”, or whether journalism should even be taught at universities, are no longer fruitful or even interesting for teachers in tertiary environments. The far more important discussion around the teaching of journalism should be on the approach which focuses too exclusively on its nature as a “profession” and so ignores the critical function of journalists in the world as “interpretive communities”.
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Technology solutions to strengthen the integration of marginalized communities into the global knowledge society
- Hlungulu, Bulumko, Kunjuzwa, Dumani, Ndlovu, Nyankiso, Samalenge, Jimmy, Sikhumbuzo, Ngwenya, Thinyane, Mamello, Terzoli, Alfredo
- Authors: Hlungulu, Bulumko , Kunjuzwa, Dumani , Ndlovu, Nyankiso , Samalenge, Jimmy , Sikhumbuzo, Ngwenya , Thinyane, Mamello , Terzoli, Alfredo
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430769 , vital:72714 , https://ieeexplore.ieee.org/abstract/document/5753005
- Description: Information and Communication Technology (ICT) has made it possible to explore novel and innovative mechanisms to leap-frog socio-economic development in rural and marginalized communities. An ICT for development intervention called Siyakhula Living Lab (SLL) has been underway in Dwesa, a rural community in the Eastern Cape Prov-ince, for the past four years. The living lab methodology, which enables user-driven innovation within a multi-stakeholder relationship of aca-demia, user communities, government and private industry, has facili-tated greater integration of the Dwesa community into the digital ecolo-gy and subsequently the knowledge society. This paper introduces the SLL intervention, discusses the SLL's supporting technical infrastruc-ture and the interventions that are undertaken towards long-term sus-tainability of the project. The developed eServices are also discussed, with a view to highlighting the key characteristics that contribute to in-creased context-sensitivity, ownership, and buy-in from the community.
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- Authors: Hlungulu, Bulumko , Kunjuzwa, Dumani , Ndlovu, Nyankiso , Samalenge, Jimmy , Sikhumbuzo, Ngwenya , Thinyane, Mamello , Terzoli, Alfredo
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430769 , vital:72714 , https://ieeexplore.ieee.org/abstract/document/5753005
- Description: Information and Communication Technology (ICT) has made it possible to explore novel and innovative mechanisms to leap-frog socio-economic development in rural and marginalized communities. An ICT for development intervention called Siyakhula Living Lab (SLL) has been underway in Dwesa, a rural community in the Eastern Cape Prov-ince, for the past four years. The living lab methodology, which enables user-driven innovation within a multi-stakeholder relationship of aca-demia, user communities, government and private industry, has facili-tated greater integration of the Dwesa community into the digital ecolo-gy and subsequently the knowledge society. This paper introduces the SLL intervention, discusses the SLL's supporting technical infrastruc-ture and the interventions that are undertaken towards long-term sus-tainability of the project. The developed eServices are also discussed, with a view to highlighting the key characteristics that contribute to in-creased context-sensitivity, ownership, and buy-in from the community.
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The ambivalence of African elitehood:
- Authors: Matthews, Sally
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142442 , vital:38080 , DOI: 10.1177/0021909609357416
- Description: Recent discussions in South Africa about the role of the so-called patriotic bourgeoisie highlight the much debated question of what role elite Africans can and ought to play in the upliftment of the poor. Those supporting the notion of a patriotic bourgeoisie believe that national or racial solidarity is sufficient to allow privileged Africans to act in the interests of their poorer fellow citizens. However, a reconsideration of an older discussion of African elitehood, that of Amilcar Cabral, suggests that something more may be needed before elites can act in the interests of the poor. Cabral argues that elites need to renounce their privilege and to live and struggle alongside the poor if pro-poor societal transformation is to be achieved. While Cabral may be right that shared racial or national identity is insufficient for elite solidarity with the poor, he does not consider all the complexities that arise when elites actually try to work with and for the poor. A consideration of the experiences of a long-standing Senegalese NGO reveal some of these complexities and suggest that any attempt by African elites to engage meaningfully in the upliftment of the poor, will inevitably involve continuous and difficult negotiation between paternalism and naïve egalitarianism.
- Full Text:
- Authors: Matthews, Sally
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142442 , vital:38080 , DOI: 10.1177/0021909609357416
- Description: Recent discussions in South Africa about the role of the so-called patriotic bourgeoisie highlight the much debated question of what role elite Africans can and ought to play in the upliftment of the poor. Those supporting the notion of a patriotic bourgeoisie believe that national or racial solidarity is sufficient to allow privileged Africans to act in the interests of their poorer fellow citizens. However, a reconsideration of an older discussion of African elitehood, that of Amilcar Cabral, suggests that something more may be needed before elites can act in the interests of the poor. Cabral argues that elites need to renounce their privilege and to live and struggle alongside the poor if pro-poor societal transformation is to be achieved. While Cabral may be right that shared racial or national identity is insufficient for elite solidarity with the poor, he does not consider all the complexities that arise when elites actually try to work with and for the poor. A consideration of the experiences of a long-standing Senegalese NGO reveal some of these complexities and suggest that any attempt by African elites to engage meaningfully in the upliftment of the poor, will inevitably involve continuous and difficult negotiation between paternalism and naïve egalitarianism.
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The commercial agricultural economy of the East Cape: Die kommersiële landbou-ekonomie van die Oos-Kaap
- Authors: Antrobus, Geoffrey G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143079 , vital:38199 , DOI: 10.1080/03031853.1991.9524228
- Description: The East Cape, and in particular the Smaldeel area, is used to exemplify some of the characteristics and problems of commercial farming over a period of about three decades to serve as a backdrop for the broader theme of normalising South African agriculture. The regional economy is dominated by Port Elizabeth-Uitenhage and East London which account for most of the population and three-fourths of the Gross Geographic Product (GGP). Agriculture accounts for only 10% of GGP, but is one of the most labour intensive sectors in a region with 24% of its population unemployed. The agricultural economy of the region is very diversified, but livestock farming plays the most important part in all areas contributing 72% of gross income. The chief changes which have occured in East Cape farming, as elsewhere, have been the decline in the number of farms and increase in farm size, greater capital investment, increased specialisation and declining employment.
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- Authors: Antrobus, Geoffrey G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143079 , vital:38199 , DOI: 10.1080/03031853.1991.9524228
- Description: The East Cape, and in particular the Smaldeel area, is used to exemplify some of the characteristics and problems of commercial farming over a period of about three decades to serve as a backdrop for the broader theme of normalising South African agriculture. The regional economy is dominated by Port Elizabeth-Uitenhage and East London which account for most of the population and three-fourths of the Gross Geographic Product (GGP). Agriculture accounts for only 10% of GGP, but is one of the most labour intensive sectors in a region with 24% of its population unemployed. The agricultural economy of the region is very diversified, but livestock farming plays the most important part in all areas contributing 72% of gross income. The chief changes which have occured in East Cape farming, as elsewhere, have been the decline in the number of farms and increase in farm size, greater capital investment, increased specialisation and declining employment.
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The determination of acetaminophen using a carbon nanotube: graphite-based electrode
- Moghaddam, Abdolmajid B, Mohammadi, Ali, Mohammadi, Somaye, Rayeji, Danyal, Dinarvand, Rassoul, Baghi, Mansoureh, Walker, Roderick B
- Authors: Moghaddam, Abdolmajid B , Mohammadi, Ali , Mohammadi, Somaye , Rayeji, Danyal , Dinarvand, Rassoul , Baghi, Mansoureh , Walker, Roderick B
- Date: 2010
- Language: English
- Type: Article , text
- Identifier: vital:6414 , http://hdl.handle.net/10962/d1006509
- Description: The oxidation of acetaminophen was studied at a glassy carbon electrode modified with multi-walled carbon nanotubes and a graphite paste. Cyclic voltammety, differential pulse voltammetry and square wave voltammetry at various pH values, scan rates, and the effect of the ratio of nanotubes to graphite were investigated in order to optimize the parameters for the determination of acetaminophen. Square wave voltammetry is the most appropriate technique in giving a characteristic peak at 0.52 V at pH 5. The porous nanostructure of the electrode improves the surface area which results in an increase in the peak current. The voltammetric response is linear in the range between 75 and 2000 ng.mL−1, with standard deviations between 0.25 and 7.8%, and a limit of detection of 25 ng.mL−1. The method has been successfully applied to the analysis of acetaminophen in tablets and biological fluids.
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- Authors: Moghaddam, Abdolmajid B , Mohammadi, Ali , Mohammadi, Somaye , Rayeji, Danyal , Dinarvand, Rassoul , Baghi, Mansoureh , Walker, Roderick B
- Date: 2010
- Language: English
- Type: Article , text
- Identifier: vital:6414 , http://hdl.handle.net/10962/d1006509
- Description: The oxidation of acetaminophen was studied at a glassy carbon electrode modified with multi-walled carbon nanotubes and a graphite paste. Cyclic voltammety, differential pulse voltammetry and square wave voltammetry at various pH values, scan rates, and the effect of the ratio of nanotubes to graphite were investigated in order to optimize the parameters for the determination of acetaminophen. Square wave voltammetry is the most appropriate technique in giving a characteristic peak at 0.52 V at pH 5. The porous nanostructure of the electrode improves the surface area which results in an increase in the peak current. The voltammetric response is linear in the range between 75 and 2000 ng.mL−1, with standard deviations between 0.25 and 7.8%, and a limit of detection of 25 ng.mL−1. The method has been successfully applied to the analysis of acetaminophen in tablets and biological fluids.
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The effects of economic incentives in controlling pollution in the South African leather industry: die uitwerking van ekonomiese insentiewe op die beheer van besoedeling in die Suid-Afrikaanse leerbedryf
- Mowat, Shaun P, Antrobus, Geoffrey G, Fraser, Gavin C G
- Authors: Mowat, Shaun P , Antrobus, Geoffrey G , Fraser, Gavin C G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143057 , vital:38197 , DOI: 10.1080/03031853.1997.9523487
- Description: Pollution of the environment is becoming an increasingly serious problem. A large contributor to this is industry which generates effluent as a by-product of its production process. Two methods of controlling the pollution generated by industry are the so-called “command and control” techniques and economic incentives. In theory, economic incentives promise a more economically efficient and equitable means of pollution control. This paper sets out to ascertain whether this would hold in practice by applying environmental economic theory to the practical problem of controlling the effluent generated by one particular industry, viz the South African leather industry.
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- Authors: Mowat, Shaun P , Antrobus, Geoffrey G , Fraser, Gavin C G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143057 , vital:38197 , DOI: 10.1080/03031853.1997.9523487
- Description: Pollution of the environment is becoming an increasingly serious problem. A large contributor to this is industry which generates effluent as a by-product of its production process. Two methods of controlling the pollution generated by industry are the so-called “command and control” techniques and economic incentives. In theory, economic incentives promise a more economically efficient and equitable means of pollution control. This paper sets out to ascertain whether this would hold in practice by applying environmental economic theory to the practical problem of controlling the effluent generated by one particular industry, viz the South African leather industry.
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The effects of point of substitution on the electrochemical behavior of new manganese phthalocyanines, tetra-substituted with diethylaminoethanethiol
- Akinbulu, Isaac Adebayo, Nyokong, Tebello
- Authors: Akinbulu, Isaac Adebayo , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/249137 , vital:51781 , xlink:href="https://doi.org/10.1016/j.ica.2010.06.003"
- Description: The syntheses and comparative studies of the spectral, voltammetry and spectroelectrochemical properties of new manganese phthalocyanine complexes, tetra-substituted with diethylaminoethanethio at the peripheral (complex 3a) and non-peripheral positions (complex 3b) are reported. Solution electrochemistry of complex 3a showed quasi-reversible metal-based (MnIIIPc−2/MnIIPc−2, E1/2 = −0.07 V vs. Ag|AgCl) and ring-based (MnIIPc−2/MnIIPc−3, E1/2 = −0.78 V vs. Ag|AgCl) reductions, but no ring-based oxidation. However, complex 3b showed weak irreversible ring-oxidation signal (Ep = +0.86 vs. Ag|AgCl). Reversible metal-based (MnIIIPc−2/MnIIPc−2, E1/2 = −0.04 V vs. Ag|AgCl) and ring-based (MnIIPc−2/MnIIPc−3, E1/2 = −0.68 V vs. Ag|AgCl) reductions were also observed for complex 3b. Spectroelectrochemistry was used to confirm these processes. Reduction process involving the metal (MnIIIPc−2/MnIIPc−2) was associated with the formation of manganese μ-oxo complex in complex 3a.
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- Authors: Akinbulu, Isaac Adebayo , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/249137 , vital:51781 , xlink:href="https://doi.org/10.1016/j.ica.2010.06.003"
- Description: The syntheses and comparative studies of the spectral, voltammetry and spectroelectrochemical properties of new manganese phthalocyanine complexes, tetra-substituted with diethylaminoethanethio at the peripheral (complex 3a) and non-peripheral positions (complex 3b) are reported. Solution electrochemistry of complex 3a showed quasi-reversible metal-based (MnIIIPc−2/MnIIPc−2, E1/2 = −0.07 V vs. Ag|AgCl) and ring-based (MnIIPc−2/MnIIPc−3, E1/2 = −0.78 V vs. Ag|AgCl) reductions, but no ring-based oxidation. However, complex 3b showed weak irreversible ring-oxidation signal (Ep = +0.86 vs. Ag|AgCl). Reversible metal-based (MnIIIPc−2/MnIIPc−2, E1/2 = −0.04 V vs. Ag|AgCl) and ring-based (MnIIPc−2/MnIIPc−3, E1/2 = −0.68 V vs. Ag|AgCl) reductions were also observed for complex 3b. Spectroelectrochemistry was used to confirm these processes. Reduction process involving the metal (MnIIIPc−2/MnIIPc−2) was associated with the formation of manganese μ-oxo complex in complex 3a.
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The effects of point of substitution on the formation of manganese phthalocyanine-based molecular materials
- Akinbulu, Isaac Adebayo, Khene, Samson, Nyokong, Tebello
- Authors: Akinbulu, Isaac Adebayo , Khene, Samson , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/249103 , vital:51778 , xlink:href="https://doi.org/10.1016/j.tsf.2010.08.145"
- Description: Molecular films of manganese phthalocyanine (MnPc) complexes, tetra-substituted with 2-diethylaminoethanethio at the peripheral (Mn(OAc)-β-TDEAETPc, 1) and non-peripheral (Mn(OAc)-α-TDEAETPc, 2) positions were formed on glassy carbon electrode by electropolymerization and electrodeposition respectively. Atomic force microscopy images confirmed the presence of the films and revealed significant morphological differences. The films exhibited an electrocatalytic activity towards the oxidation of the insecticide, bendiocarb. Hydrodynamic technique, using rotating disc electrode voltammetry, was used to investigate the kinetics of electro-oxidation of the insecticide. Morphological differences of the films significantly influenced kinetic parameters. Values of Tafel slopes, obtained from Tafel plots, suggested that catalysis of bendiocarb occurred via outer sphere mechanism.
- Full Text:
- Authors: Akinbulu, Isaac Adebayo , Khene, Samson , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/249103 , vital:51778 , xlink:href="https://doi.org/10.1016/j.tsf.2010.08.145"
- Description: Molecular films of manganese phthalocyanine (MnPc) complexes, tetra-substituted with 2-diethylaminoethanethio at the peripheral (Mn(OAc)-β-TDEAETPc, 1) and non-peripheral (Mn(OAc)-α-TDEAETPc, 2) positions were formed on glassy carbon electrode by electropolymerization and electrodeposition respectively. Atomic force microscopy images confirmed the presence of the films and revealed significant morphological differences. The films exhibited an electrocatalytic activity towards the oxidation of the insecticide, bendiocarb. Hydrodynamic technique, using rotating disc electrode voltammetry, was used to investigate the kinetics of electro-oxidation of the insecticide. Morphological differences of the films significantly influenced kinetic parameters. Values of Tafel slopes, obtained from Tafel plots, suggested that catalysis of bendiocarb occurred via outer sphere mechanism.
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The gap between what 'ought' to be and what students want
- Authors: Boshoff, Priscilla A
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70812 , vital:29747
- Description: There’s no curriculum! There’s no curriculum!” The young man in the focus group was so frustrated that he had to repeat himself, not just once, but several times. I had just asked the group what their feelings were about their second-year coursework. His sentiments were echoed by many of the students in the group, all of whom had passed the rigorous application process into second year at Rhodes University’s School of Journalism and Media Studies.
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- Authors: Boshoff, Priscilla A
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70812 , vital:29747
- Description: There’s no curriculum! There’s no curriculum!” The young man in the focus group was so frustrated that he had to repeat himself, not just once, but several times. I had just asked the group what their feelings were about their second-year coursework. His sentiments were echoed by many of the students in the group, all of whom had passed the rigorous application process into second year at Rhodes University’s School of Journalism and Media Studies.
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The genus Boccardia (Polychaeta: Spionidae) associated with mollusc shells on the south coast of South Africa
- Simon, Carol A, Worsfold, T M, Lange, Louise, Sterley, Jessica A
- Authors: Simon, Carol A , Worsfold, T M , Lange, Louise , Sterley, Jessica A
- Date: 2010
- Language: English
- Type: text , Article
- Identifier: vital:6873 , http://hdl.handle.net/10962/d1011620 , http://dx.doi.org/10.1017/S0025315409990452
- Description: Three species of Boccardia (B. polybranchia, B. pseudonatrix and B. proboscidea) were associated with mollusc shells on the south and south-east coasts of South Africa. Boccardia polybranchia was widely distributed along the coast and falls within the known distribution range of this species. Comparisons with material from other, international, locations showed that some specimens have been misidentified. No characters could be found to characterize distinct species for different regions within the range of B. polybranchia, as currently recognized. Boccardia pseudonatrix was found only at the most eastern site, increasing its known distribution range. Boccardia proboscidea, a non-indigenous species, was found only on abalone farms and was most abundant in the west.
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- Authors: Simon, Carol A , Worsfold, T M , Lange, Louise , Sterley, Jessica A
- Date: 2010
- Language: English
- Type: text , Article
- Identifier: vital:6873 , http://hdl.handle.net/10962/d1011620 , http://dx.doi.org/10.1017/S0025315409990452
- Description: Three species of Boccardia (B. polybranchia, B. pseudonatrix and B. proboscidea) were associated with mollusc shells on the south and south-east coasts of South Africa. Boccardia polybranchia was widely distributed along the coast and falls within the known distribution range of this species. Comparisons with material from other, international, locations showed that some specimens have been misidentified. No characters could be found to characterize distinct species for different regions within the range of B. polybranchia, as currently recognized. Boccardia pseudonatrix was found only at the most eastern site, increasing its known distribution range. Boccardia proboscidea, a non-indigenous species, was found only on abalone farms and was most abundant in the west.
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The geochemistry and evolution of Palaeogene phonolites, central Namibia:
- Authors: Marsh, Julian S
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145000 , vital:38399 , https://doi.org/10.1016/j.lithos.2010.02.012
- Description: Phonolites of Palaeogene age occur at two different localities in central Namibia, occurring as clusters of eroded monogenetic lava domes. Six phonolites at Aris collectively exhibit a narrow compositional range and represent a single magma system of highly evolved phonolite with high concentrations of Na2O, Rb, Th, Zr, Zn, Pb, and REE and very low abundances of MgO, P2O5, Sr and Ba. No mafic rocks are associated with the Aris phonolites and their ultimate petrogenetic origin remains obscure. The more abundant Staalhart phonolites exhibit more variable but scattered compositional variation consistent with fractional crystallization dominated by sanidine (and nepheline) and pyroxene. The behaviour of REE is decoupled from Zr, Nb, and Th in this suite indicating a controlling role for minor phases in their evolution. The least evolved phonolites have initial 87Sr/86Sr 0.7043, which is identical to a small occurrence of associated plagioclase-bearing nephelinite indicating a possible petrogenetic link.
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- Authors: Marsh, Julian S
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145000 , vital:38399 , https://doi.org/10.1016/j.lithos.2010.02.012
- Description: Phonolites of Palaeogene age occur at two different localities in central Namibia, occurring as clusters of eroded monogenetic lava domes. Six phonolites at Aris collectively exhibit a narrow compositional range and represent a single magma system of highly evolved phonolite with high concentrations of Na2O, Rb, Th, Zr, Zn, Pb, and REE and very low abundances of MgO, P2O5, Sr and Ba. No mafic rocks are associated with the Aris phonolites and their ultimate petrogenetic origin remains obscure. The more abundant Staalhart phonolites exhibit more variable but scattered compositional variation consistent with fractional crystallization dominated by sanidine (and nepheline) and pyroxene. The behaviour of REE is decoupled from Zr, Nb, and Th in this suite indicating a controlling role for minor phases in their evolution. The least evolved phonolites have initial 87Sr/86Sr 0.7043, which is identical to a small occurrence of associated plagioclase-bearing nephelinite indicating a possible petrogenetic link.
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The largest volcanic eruptions on Earth
- Bryan, Scott E, Peate, Ingrid Ukstins, Peate, David W, Self, Stephen, Jerram, Dougal A, Mawby, Michael R, Marsh, Julian S, Miller, Jodie A
- Authors: Bryan, Scott E , Peate, Ingrid Ukstins , Peate, David W , Self, Stephen , Jerram, Dougal A , Mawby, Michael R , Marsh, Julian S , Miller, Jodie A
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/132887 , vital:36902 , https://doi.org/10.1016/j.earscirev.2010.07.001
- Description: Large igneous provinces (LIPs) are sites of the most frequently recurring, largest volume basaltic and silicic eruptions in Earth history. These large-volume (> 1000 km3 dense rock equivalent) and large-magnitude (> M8) eruptions produce really extensive (104–105 km2) basaltic lava flow fields and silicic ignimbrites that are the main building blocks of LIPs.
- Full Text: false
- Authors: Bryan, Scott E , Peate, Ingrid Ukstins , Peate, David W , Self, Stephen , Jerram, Dougal A , Mawby, Michael R , Marsh, Julian S , Miller, Jodie A
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/132887 , vital:36902 , https://doi.org/10.1016/j.earscirev.2010.07.001
- Description: Large igneous provinces (LIPs) are sites of the most frequently recurring, largest volume basaltic and silicic eruptions in Earth history. These large-volume (> 1000 km3 dense rock equivalent) and large-magnitude (> M8) eruptions produce really extensive (104–105 km2) basaltic lava flow fields and silicic ignimbrites that are the main building blocks of LIPs.
- Full Text: false
The Makana Regional Centre of expertise: Experiments in social learning
- Lotz-Sisitka, Heila, O'Donoghue, Rob, Wilmot, P Dianne
- Authors: Lotz-Sisitka, Heila , O'Donoghue, Rob , Wilmot, P Dianne
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182634 , vital:43849 , xlink:href="https://doi.org/10.1177/097340820900400114"
- Description: This article deliberates the possibilities for Regional Centres of Expertise (RCEs) to become ‘experiments’ in social learning. The purpose of the article is to advance the broader research agenda of RCEs through reflection on the empirical research agenda of one RCE, Makana RCE in South Africa. As such it opens questions on how we might see RCE’s as morphogenic social learning processes (i.e., processes of social change). It provides an oversight of the key issues, educational foci and developing areas of engagement in the Makana RCE. These provide an overview of the ‘starting points’ for social learning in the Makana RCE. A model of social learning is also provided which seeks to engage the ecocultural nature of sustainability practices in the Makana RCE.
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- Authors: Lotz-Sisitka, Heila , O'Donoghue, Rob , Wilmot, P Dianne
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182634 , vital:43849 , xlink:href="https://doi.org/10.1177/097340820900400114"
- Description: This article deliberates the possibilities for Regional Centres of Expertise (RCEs) to become ‘experiments’ in social learning. The purpose of the article is to advance the broader research agenda of RCEs through reflection on the empirical research agenda of one RCE, Makana RCE in South Africa. As such it opens questions on how we might see RCE’s as morphogenic social learning processes (i.e., processes of social change). It provides an oversight of the key issues, educational foci and developing areas of engagement in the Makana RCE. These provide an overview of the ‘starting points’ for social learning in the Makana RCE. A model of social learning is also provided which seeks to engage the ecocultural nature of sustainability practices in the Makana RCE.
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The Oppressor's Pathology
- Authors: Tabensky, Pedro
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/305750 , vital:58609 , xlink:href="https://doi.org/10.3167/th.2010.5712505"
- Description: In Black Skin, White Masks Frantz Fanon discusses the neurotic condition that typifies the oppressed black subject, their ‘psychoexistential complex’. He argues that this neurotic condition is closely related to another, the ‘psychoexistential complex’ of the white oppressor. Both of these complexes sustain and are sustained by social and economic injustice. But Fanon does not delve in detail into the nature of this second neurosis, for he was primarily interested in discussing this neurosis only insofar as it helps him understand the first. My aim in this paper is to provide an account of the white neurosis, and why it should be understood literally as a neurotic condition. Typical, white oppressors, not solely those who are militantly committed to oppressing others, are alienated from the world and from themselves, making their behaviour seem like that of soulless dolls, to use J.M. Coetzee’s image from Age of Iron.
- Full Text:
- Authors: Tabensky, Pedro
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/305750 , vital:58609 , xlink:href="https://doi.org/10.3167/th.2010.5712505"
- Description: In Black Skin, White Masks Frantz Fanon discusses the neurotic condition that typifies the oppressed black subject, their ‘psychoexistential complex’. He argues that this neurotic condition is closely related to another, the ‘psychoexistential complex’ of the white oppressor. Both of these complexes sustain and are sustained by social and economic injustice. But Fanon does not delve in detail into the nature of this second neurosis, for he was primarily interested in discussing this neurosis only insofar as it helps him understand the first. My aim in this paper is to provide an account of the white neurosis, and why it should be understood literally as a neurotic condition. Typical, white oppressors, not solely those who are militantly committed to oppressing others, are alienated from the world and from themselves, making their behaviour seem like that of soulless dolls, to use J.M. Coetzee’s image from Age of Iron.
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