Anton and Vale van der Merwe: reinterpreting Afro-Oriental studio ceramics traditions in South Africa
- Authors: Steele, John
- Date: 2015
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/11260/968 , vital:30077
- Description: Growing awareness of ancient Chinese Song and Yuan ceramics, amongst other Oriental traditions, by people with western connections such as Bernard Leach and Michael Cardew, in conjunction with influences from Japanese associates such as Soyetsu Yanagi, Kenkichi Tomimoto, and Shoji Hamada, (De Waal 1997, Harrod 2012, Kikuchi 1977, Leach 1976) has had many consequences. It spread a consciousness idealizing self-sufficient pottery studios where potters were in touch with all aspects of creating utilityware, largely from local materials for local use. Out of this emerged an Anglo-Oriental studio ceramic philosophy of form and practice, associated mainly with hand-made high temperature reduction fired ceramics. These ideas spread to South Africa in the late 1950s, and by the early 1960s local studios were being established along these lines. This studio ceramics movement grew exponentially in South Africa, initiating a phase of Afro-Oriental ceramics that remains a powerful way of life and visual arts influence. This paper seeks to explore aspects of Afro- Oriental studio ceramics in South Africa, with particular reference to the Leach/Hamada/Cardew to Rabinowitz, and Van der Merwe lineage.
- Full Text:
- Date Issued: 2015
- Authors: Steele, John
- Date: 2015
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/11260/968 , vital:30077
- Description: Growing awareness of ancient Chinese Song and Yuan ceramics, amongst other Oriental traditions, by people with western connections such as Bernard Leach and Michael Cardew, in conjunction with influences from Japanese associates such as Soyetsu Yanagi, Kenkichi Tomimoto, and Shoji Hamada, (De Waal 1997, Harrod 2012, Kikuchi 1977, Leach 1976) has had many consequences. It spread a consciousness idealizing self-sufficient pottery studios where potters were in touch with all aspects of creating utilityware, largely from local materials for local use. Out of this emerged an Anglo-Oriental studio ceramic philosophy of form and practice, associated mainly with hand-made high temperature reduction fired ceramics. These ideas spread to South Africa in the late 1950s, and by the early 1960s local studios were being established along these lines. This studio ceramics movement grew exponentially in South Africa, initiating a phase of Afro-Oriental ceramics that remains a powerful way of life and visual arts influence. This paper seeks to explore aspects of Afro- Oriental studio ceramics in South Africa, with particular reference to the Leach/Hamada/Cardew to Rabinowitz, and Van der Merwe lineage.
- Full Text:
- Date Issued: 2015
Whose voice is it anyway?
- Authors: Krueger, Anton
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/225695 , vital:49249 , xlink:href="https://doi.org/10.1080/1013929X.2015.1086195"
- Description: This essay surveys a number of different interpretations of the metaphor of “voice”. It begins by exploring the use of free writing exercises as a means of nurturing the emergence of physical (audible) voice in creative writing classes before assessing some of the ramifications and implications of the trope, both diachronically and synchronically. A key issue of this discussion is whether voice is regarded as individual or social.
- Full Text:
- Date Issued: 2015
- Authors: Krueger, Anton
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/225695 , vital:49249 , xlink:href="https://doi.org/10.1080/1013929X.2015.1086195"
- Description: This essay surveys a number of different interpretations of the metaphor of “voice”. It begins by exploring the use of free writing exercises as a means of nurturing the emergence of physical (audible) voice in creative writing classes before assessing some of the ramifications and implications of the trope, both diachronically and synchronically. A key issue of this discussion is whether voice is regarded as individual or social.
- Full Text:
- Date Issued: 2015
Uncle Noodle
- Authors: Krueger, Anton
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229676 , vital:49699 , xlink:href="https://hdl.handle.net/10520/EJC176906"
- Description: “Ah,” he seemed surprised to see me, “Now you find out who really cares...” His kidneys hadn‟t been on the job in months, and with the machines failing, his hands were fattening into stubby yellow fingers, as the waste shored up inside of him. I touched his arm, and we joked about the broad blunt strokes of the casiotone the old dame played for the lunch-eaters next door. Uncle Noodle had always been my favourite. In a world where adults were always certain, ready to disdain and judge and pass verdict – I loved it that he was indecisive, insecure, unsure. Often wretched, often defeated. His heart had chasmed in the wake of his wife‟s leaving, finally dividing him from all his hopes, collapsing his dignity destroying his happiness machinery.
- Full Text:
- Date Issued: 2015
- Authors: Krueger, Anton
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229676 , vital:49699 , xlink:href="https://hdl.handle.net/10520/EJC176906"
- Description: “Ah,” he seemed surprised to see me, “Now you find out who really cares...” His kidneys hadn‟t been on the job in months, and with the machines failing, his hands were fattening into stubby yellow fingers, as the waste shored up inside of him. I touched his arm, and we joked about the broad blunt strokes of the casiotone the old dame played for the lunch-eaters next door. Uncle Noodle had always been my favourite. In a world where adults were always certain, ready to disdain and judge and pass verdict – I loved it that he was indecisive, insecure, unsure. Often wretched, often defeated. His heart had chasmed in the wake of his wife‟s leaving, finally dividing him from all his hopes, collapsing his dignity destroying his happiness machinery.
- Full Text:
- Date Issued: 2015
Maximum firepower: Vale van der Merwe, an emergent ceramic artist at Starways Arts, Hogsback, Eastern Cape, South Africa
- Authors: Steele, John
- Date: 2015
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/11260/979 , vital:30078
- Description: Vale van der Merwe has been working as a ceramic artist for the past five years, and in that time has developed a remarkably diverse repertoire of both thrown and handbuilt works. These include rapidly thrown utilityware as well as carefully conceived sculptural works that engage with ideas rather than primarily with function. She also makes full use of opportunities offered by high-temperature woodburn firings, and despite works collapsing while being made, breaking while being carried to the kiln and slumping during firing, she has used such occasions as opportunities for learning rather than despondency. Van der Merwe is also an actively hands-on ceramic artist who engages with all levels of tasks associated with studio ceramics in a village setting, so has found herself, for example, both creating a new chimney for the kiln, and simultaneously leading discussion around concepts for new collaborative exhibitions. There is a seriousness of intent combined with infectious confidence evident in both her daily presence and ceramics, and it is hoped that she will develop her repertoire and thinkings even further in forthcoming years.
- Full Text:
- Date Issued: 2015
- Authors: Steele, John
- Date: 2015
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/11260/979 , vital:30078
- Description: Vale van der Merwe has been working as a ceramic artist for the past five years, and in that time has developed a remarkably diverse repertoire of both thrown and handbuilt works. These include rapidly thrown utilityware as well as carefully conceived sculptural works that engage with ideas rather than primarily with function. She also makes full use of opportunities offered by high-temperature woodburn firings, and despite works collapsing while being made, breaking while being carried to the kiln and slumping during firing, she has used such occasions as opportunities for learning rather than despondency. Van der Merwe is also an actively hands-on ceramic artist who engages with all levels of tasks associated with studio ceramics in a village setting, so has found herself, for example, both creating a new chimney for the kiln, and simultaneously leading discussion around concepts for new collaborative exhibitions. There is a seriousness of intent combined with infectious confidence evident in both her daily presence and ceramics, and it is hoped that she will develop her repertoire and thinkings even further in forthcoming years.
- Full Text:
- Date Issued: 2015
The development of biological tools to aid in the genetic investigation of the black (Diceros bicornis) and white (Ceratotherium simum) rhinoceros mitochondrial genomes
- Authors: Parsons, Michelle
- Date: 2015
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/56059 , vital:26769
- Description: The black (Diceros bicornis) and white (Ceratotherium simum) rhinoceros are found in South Africa. A decline in the populations of these species has resulted due to human activities such as habitat fragmentation and poaching. This has contributed to the loss of genetic diversity amongst the black and white rhinoceros. Conservation and anti-poaching efforts are needed to help maintain genetic diversity. These efforts could be improved through the development of non-invasive techniques to examine DNA from threatened animals. The aim of this research was to develop a molecular technique which would allow for the identification of the black and white rhinoceros and to develop a molecular technique which would allow for intraspecies genetic variation to be examined. DNA extractions were performed on matched faecal and tissue samples that were collected from two regions in South Africa. Polymerase chain reaction (PCR) primer sets were designed to investigate several regions of the rhinoceros mitochondrial genome. PCR optimisation was completed for the target regions. Sequencing was conducted on all final PCR products. The cytochrome c oxidase subunit 1 (COIi) gene allowed for the rhinoceros family to be identified. This region was digested with the HindIII restriction enzyme, which allowed for the specific identification of either the black or white rhinoceros. A subsequent region of the cytochrome c oxidase subunit 1 (COIii) as well as the D-loop, hypervariable regions (HV1 and HV2), cytochrome b (cytb) and 16s rRNA regions were investigated. These regions displayed potential for establishing geographic origin for black rhinoceros samples, whereas the D-loop and HV2 show potential for the white rhinoceros. The white rhinoceros displayed sequence variation in the HV2 and cytb region, while variation was observed in the COIi and HV1 for the black rhinoceros. All investigated target regions allowed for the rhinoceros family to be identified. The COI (COIi and COIii), HV2 and cytb regions allowed for the subspecies of rhinoceros to be identified, however the D-loop was not able to identify the white rhinoceros species. The 16s rRNA and HV1 regions allowed for the correct subspecies of rhinoceros to be identified, however as the primers were only compatible for the black rhinoceros therefore a subsequent investigation is required for the white rhinoceros. The establishment of this novel PCR based technique to identify white and black rhinoceros will allow for efficient species identification in wildlife forensic cases. A biological method was established to study intraspecies variation for the white and black rhinoceros; however the investigated target regions did not yield sufficient genetic variation. The core techniques developed in this study will be valuable for future studies that wish to investigate genetic variation in mammal species.
- Full Text:
- Date Issued: 2015
- Authors: Parsons, Michelle
- Date: 2015
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/56059 , vital:26769
- Description: The black (Diceros bicornis) and white (Ceratotherium simum) rhinoceros are found in South Africa. A decline in the populations of these species has resulted due to human activities such as habitat fragmentation and poaching. This has contributed to the loss of genetic diversity amongst the black and white rhinoceros. Conservation and anti-poaching efforts are needed to help maintain genetic diversity. These efforts could be improved through the development of non-invasive techniques to examine DNA from threatened animals. The aim of this research was to develop a molecular technique which would allow for the identification of the black and white rhinoceros and to develop a molecular technique which would allow for intraspecies genetic variation to be examined. DNA extractions were performed on matched faecal and tissue samples that were collected from two regions in South Africa. Polymerase chain reaction (PCR) primer sets were designed to investigate several regions of the rhinoceros mitochondrial genome. PCR optimisation was completed for the target regions. Sequencing was conducted on all final PCR products. The cytochrome c oxidase subunit 1 (COIi) gene allowed for the rhinoceros family to be identified. This region was digested with the HindIII restriction enzyme, which allowed for the specific identification of either the black or white rhinoceros. A subsequent region of the cytochrome c oxidase subunit 1 (COIii) as well as the D-loop, hypervariable regions (HV1 and HV2), cytochrome b (cytb) and 16s rRNA regions were investigated. These regions displayed potential for establishing geographic origin for black rhinoceros samples, whereas the D-loop and HV2 show potential for the white rhinoceros. The white rhinoceros displayed sequence variation in the HV2 and cytb region, while variation was observed in the COIi and HV1 for the black rhinoceros. All investigated target regions allowed for the rhinoceros family to be identified. The COI (COIi and COIii), HV2 and cytb regions allowed for the subspecies of rhinoceros to be identified, however the D-loop was not able to identify the white rhinoceros species. The 16s rRNA and HV1 regions allowed for the correct subspecies of rhinoceros to be identified, however as the primers were only compatible for the black rhinoceros therefore a subsequent investigation is required for the white rhinoceros. The establishment of this novel PCR based technique to identify white and black rhinoceros will allow for efficient species identification in wildlife forensic cases. A biological method was established to study intraspecies variation for the white and black rhinoceros; however the investigated target regions did not yield sufficient genetic variation. The core techniques developed in this study will be valuable for future studies that wish to investigate genetic variation in mammal species.
- Full Text:
- Date Issued: 2015
Rhodes University Research Report 2015
- Rhodes University, Gillitt, Tarryn, Goba, Busi, Macgregor, Jill, Roberts, Jaine, Dore, Sally
- Authors: Rhodes University , Gillitt, Tarryn , Goba, Busi , Macgregor, Jill , Roberts, Jaine , Dore, Sally
- Date: 2015
- Language: English
- Type: Text
- Identifier: http://hdl.handle.net/10962/59298 , vital:27546
- Description: From Foreword by Dr Sizwe Mabizela: A further feature of research at Rhodes University has long been international collaborations, many of them responsible for raising the international competitiveness and voice of scholarship involving Rhodes academics and students. In March 2015, Rhodes University became a founder member of the African Research Universities’ Alliance (ARUA), launched at the African Higher Education Summit in Senegal. Leading universities with strong programmes of research and Postgraduate training formed the network of 16 institutions, which aim to bring together intersecting and complementary strengths in the interest of building critical mass in the key development priorities of the African continent. , A publication of the Rhodes University Research Office, compiled and edited by Tarryn Gillitt, Busi Goba, Patricia Jacob, Jill Macgregor and Jaine Roberts. Design & Layout: Sally Dore.
- Full Text:
- Date Issued: 2015
- Authors: Rhodes University , Gillitt, Tarryn , Goba, Busi , Macgregor, Jill , Roberts, Jaine , Dore, Sally
- Date: 2015
- Language: English
- Type: Text
- Identifier: http://hdl.handle.net/10962/59298 , vital:27546
- Description: From Foreword by Dr Sizwe Mabizela: A further feature of research at Rhodes University has long been international collaborations, many of them responsible for raising the international competitiveness and voice of scholarship involving Rhodes academics and students. In March 2015, Rhodes University became a founder member of the African Research Universities’ Alliance (ARUA), launched at the African Higher Education Summit in Senegal. Leading universities with strong programmes of research and Postgraduate training formed the network of 16 institutions, which aim to bring together intersecting and complementary strengths in the interest of building critical mass in the key development priorities of the African continent. , A publication of the Rhodes University Research Office, compiled and edited by Tarryn Gillitt, Busi Goba, Patricia Jacob, Jill Macgregor and Jaine Roberts. Design & Layout: Sally Dore.
- Full Text:
- Date Issued: 2015
Being for others : critical reflections on the stranger, the estranged and the self in participatory art
- Authors: Munro, Samantha Fawn
- Date: 2015
- Subjects: Self , Identity (Philosophical concept) in art , Alienation (Philosophy) , Interactive art , Art appreciation , Art exhibition audiences , Interactive art -- Themes, motives , Social interaction
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2507 , http://hdl.handle.net/10962/d1017771
- Description: By referring to established concepts and theories which contemplate our experiences in relation to others and space, this thesis examines the interactions and responses of an audience during various participatory artworks. I draw upon Jean-Paul Sartre’s Being and Nothingness and Elizabeth Grosz’ Architecture From The Outside: Essays on Virtual and Real Space in order to understand our interactions with other people, our interactions inside an environment, and the objects and ceremonies we use during these interactions. I align these experiences with the methods which are employed to anticipate and create the interactions between an audience and a participatory artwork. Our daily interactions can be considered a frame that an artist shapes for their represented situation to allow, provide and guide an audience towards their possibilities for movements and actions within a participatory artwork. The interactions that occur in participatory art are done in relation to others and include groups of people interacting with each other rather than an individual disembodied experience. I refer to Claire Bishop in her book, Artificial Hells, and Nicolas Bourriaud in Relational Aesthetics in order to define participatory art. In defining participatory art I focus on the idea that participation is a social activity without which the artwork does not function or exist. I unravel Brett Bailey’s Exhibit A, Anthea Moys Anthea Moys vs The City of Grahamstown and Christian Boltanski’s Personnes in terms of the frame they use to construct participation and interaction. I refer to my own exhibition Ineffaceable as an exploration of these frames which encourage participation. The inside and the outside are a constant theme throughout this thesis and my exhibition. This thematic re-emerges in relation to a number of opposing and fluctuating dynamics: the self and the other; the object and the subject; familiarity and strangeness; the participator and the spectator; the immersive and the disembodied; and the artwork and the audience. Participatory art has not been sufficiently explored particularly in South Africa with South African case studies and particularly from a practical standpoint that includes methodologies for creating participation. This thesis hopes to enrich and contribute to the contemplations on participatory art by focusing on our interactions with others.
- Full Text:
- Date Issued: 2015
- Authors: Munro, Samantha Fawn
- Date: 2015
- Subjects: Self , Identity (Philosophical concept) in art , Alienation (Philosophy) , Interactive art , Art appreciation , Art exhibition audiences , Interactive art -- Themes, motives , Social interaction
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2507 , http://hdl.handle.net/10962/d1017771
- Description: By referring to established concepts and theories which contemplate our experiences in relation to others and space, this thesis examines the interactions and responses of an audience during various participatory artworks. I draw upon Jean-Paul Sartre’s Being and Nothingness and Elizabeth Grosz’ Architecture From The Outside: Essays on Virtual and Real Space in order to understand our interactions with other people, our interactions inside an environment, and the objects and ceremonies we use during these interactions. I align these experiences with the methods which are employed to anticipate and create the interactions between an audience and a participatory artwork. Our daily interactions can be considered a frame that an artist shapes for their represented situation to allow, provide and guide an audience towards their possibilities for movements and actions within a participatory artwork. The interactions that occur in participatory art are done in relation to others and include groups of people interacting with each other rather than an individual disembodied experience. I refer to Claire Bishop in her book, Artificial Hells, and Nicolas Bourriaud in Relational Aesthetics in order to define participatory art. In defining participatory art I focus on the idea that participation is a social activity without which the artwork does not function or exist. I unravel Brett Bailey’s Exhibit A, Anthea Moys Anthea Moys vs The City of Grahamstown and Christian Boltanski’s Personnes in terms of the frame they use to construct participation and interaction. I refer to my own exhibition Ineffaceable as an exploration of these frames which encourage participation. The inside and the outside are a constant theme throughout this thesis and my exhibition. This thematic re-emerges in relation to a number of opposing and fluctuating dynamics: the self and the other; the object and the subject; familiarity and strangeness; the participator and the spectator; the immersive and the disembodied; and the artwork and the audience. Participatory art has not been sufficiently explored particularly in South Africa with South African case studies and particularly from a practical standpoint that includes methodologies for creating participation. This thesis hopes to enrich and contribute to the contemplations on participatory art by focusing on our interactions with others.
- Full Text:
- Date Issued: 2015
Nonlinear optical studies of phthalocyanines and their conjugates with nanomaterials
- Authors: Sanusi, Sikiru Olukayode
- Date: 2015
- Subjects: Phthalocyanines , Nonlinear optics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4545 , http://hdl.handle.net/10962/d1017925
- Description: A number of metallophthalocyanines (MPcs) and metal-free phthalocyanines (H₂Pcs) have been synthesized and characterized using various characterization tools such as ¹H-NMR, TOF mass spectrometry, FT-IR, UV-visible spectrophotometry and CHNS elemental analysis. Some of the MPcs were covalently linked to nanomaterials such as silica nanoparticles (SiNPs), single-walled carbon nanotubes (SWCNTs), magnetite nanoparticles (MNPs) and quantum dots (QDs), or embedded in polymer thin-films using poly(methyl methacrylate) (PMMA) and poly(acrylic acid) (PAA) as the polymer sources. The phthalocyanine-nanomaterial composites (Pc-NMCs) were characterized with FT-IR, UV-visible spectrophotometry, transmission electron microscopy (TEM), thermogravimetry analysis and X-ray diffractometry. The nonlinear optical (NLO) properties (using the open-aperture Z-scan technique) of the MPcs and the Pc-NMCs were investigated. In general, most of the investigated MPcs showed good optical limiting behaviors, except for a few, like the non-peripherally-substituted 2-pyridyloxy phthalocyanines, which showed inhibited NLO response as a result of the ring-strain effects. The absence of a metal center was found to greatly reduce the inherent high nonlinearities expected of some of the phthalocyanine complexes. The octaphenoxy derivatives (61a – 61e) were found to exhibit reverse saturable absorption (RSA) that depends on the singlet-singlet transitions, hence making them less reliable optical limiters. The optical limiting properties of the MPcs were improved in the presence of nanomaterials such as the QDs, MNPs and SWCNTs, with MPc-QDs showing the best optical limiting behavior of the three. SiNPs have no significant effect on the optical limiting behavior of the MPcs. The optical limiting properties of the MPcs were greatly enhanced in the presence of PMMA or PAA polymers. The PAA polymer showed better optical limiting behavior compared to PMMA
- Full Text:
- Date Issued: 2015
- Authors: Sanusi, Sikiru Olukayode
- Date: 2015
- Subjects: Phthalocyanines , Nonlinear optics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4545 , http://hdl.handle.net/10962/d1017925
- Description: A number of metallophthalocyanines (MPcs) and metal-free phthalocyanines (H₂Pcs) have been synthesized and characterized using various characterization tools such as ¹H-NMR, TOF mass spectrometry, FT-IR, UV-visible spectrophotometry and CHNS elemental analysis. Some of the MPcs were covalently linked to nanomaterials such as silica nanoparticles (SiNPs), single-walled carbon nanotubes (SWCNTs), magnetite nanoparticles (MNPs) and quantum dots (QDs), or embedded in polymer thin-films using poly(methyl methacrylate) (PMMA) and poly(acrylic acid) (PAA) as the polymer sources. The phthalocyanine-nanomaterial composites (Pc-NMCs) were characterized with FT-IR, UV-visible spectrophotometry, transmission electron microscopy (TEM), thermogravimetry analysis and X-ray diffractometry. The nonlinear optical (NLO) properties (using the open-aperture Z-scan technique) of the MPcs and the Pc-NMCs were investigated. In general, most of the investigated MPcs showed good optical limiting behaviors, except for a few, like the non-peripherally-substituted 2-pyridyloxy phthalocyanines, which showed inhibited NLO response as a result of the ring-strain effects. The absence of a metal center was found to greatly reduce the inherent high nonlinearities expected of some of the phthalocyanine complexes. The octaphenoxy derivatives (61a – 61e) were found to exhibit reverse saturable absorption (RSA) that depends on the singlet-singlet transitions, hence making them less reliable optical limiters. The optical limiting properties of the MPcs were improved in the presence of nanomaterials such as the QDs, MNPs and SWCNTs, with MPc-QDs showing the best optical limiting behavior of the three. SiNPs have no significant effect on the optical limiting behavior of the MPcs. The optical limiting properties of the MPcs were greatly enhanced in the presence of PMMA or PAA polymers. The PAA polymer showed better optical limiting behavior compared to PMMA
- Full Text:
- Date Issued: 2015
The synthesis and analysis of (2R,3R)-1,1,4,4- tetraphenylbutane-1,2,3,4-tetraol (tetrol) and derivatives, and a study of their host potential
- Authors: Weitz, Selwyn Herbert
- Date: 2015
- Subjects: Chemistry, Organic
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/3735 , vital:20459
- Description: This investigation focussed on the inclusion and resolution ability of (2R,3R)-1,1,4,4-tetraphenylbutane-1,2,3,4-tetraol (TETROL), studies on the stoichiometry of its derivatives and the formation of inclusion compounds for single crystal analysis. The guest compounds that featured in the main study were cyclohexanone, 2-methylcyclohexanone, 3-methylcyclohexanone and 4-methylcyclohexanone. It was found that 3- and 4-methylcyclohexanone were trapped in their energetically unfavourable axial conformations in the inclusion crystal. Resolution experiments proved that (2R,3R)-1,1,4,4-tetraphenylbutane-1,2,3,4-tetraol can be used as a resolving agent for 2- and 3-methylcyclohexanone, with ee values of 13% and 22%, respectively (according to the method of Hiemstra), in favour of the R-enantiomer. Single crystal X-ray diffraction (SCXRD) studies, however, showed that 2-methylcyclohexanone was resolved with an ee of 30% in R. An ee of 56% in R was obtained for 3-methylcyclohexanone. Enantiomer enrichment of 2-methylcyclohexanone was achieved in basic medium (ee of 18% according to the method of Hiemstra) and showed that by using the host in either half or double the molar ratio of the guest, a higher ee was obtained than for a 1:1 ratio. The following TETROL derivatives were also synthesized and their stoichiometries with various guest compounds were determined: (2R,3R)-1,1,4,4-tetra(naphthalen-1-yl)butane-1,2,3,4-tetraol; (2R,3R)-1,1,4,4-tetra(naphthalen-2-yl)butane-1,2,3,4-tetraol; (2R,3R)-1,1,4,4-tetra(p-anisyl)butane-1,2,3,4-tetraol; (2R,3R)-1,1,4,4-tetra(p-tolyl)butane-1,2,3,4-tetraol; (2R,3R)-1,1,4,4-tetra(m-tolyl)butane-1,2,3,4-tetraol and; (2R,3R)-1,1,4,4-tetra(o-tolyl)butane-1,2,3,4-tetraol.
- Full Text:
- Date Issued: 2015
- Authors: Weitz, Selwyn Herbert
- Date: 2015
- Subjects: Chemistry, Organic
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/3735 , vital:20459
- Description: This investigation focussed on the inclusion and resolution ability of (2R,3R)-1,1,4,4-tetraphenylbutane-1,2,3,4-tetraol (TETROL), studies on the stoichiometry of its derivatives and the formation of inclusion compounds for single crystal analysis. The guest compounds that featured in the main study were cyclohexanone, 2-methylcyclohexanone, 3-methylcyclohexanone and 4-methylcyclohexanone. It was found that 3- and 4-methylcyclohexanone were trapped in their energetically unfavourable axial conformations in the inclusion crystal. Resolution experiments proved that (2R,3R)-1,1,4,4-tetraphenylbutane-1,2,3,4-tetraol can be used as a resolving agent for 2- and 3-methylcyclohexanone, with ee values of 13% and 22%, respectively (according to the method of Hiemstra), in favour of the R-enantiomer. Single crystal X-ray diffraction (SCXRD) studies, however, showed that 2-methylcyclohexanone was resolved with an ee of 30% in R. An ee of 56% in R was obtained for 3-methylcyclohexanone. Enantiomer enrichment of 2-methylcyclohexanone was achieved in basic medium (ee of 18% according to the method of Hiemstra) and showed that by using the host in either half or double the molar ratio of the guest, a higher ee was obtained than for a 1:1 ratio. The following TETROL derivatives were also synthesized and their stoichiometries with various guest compounds were determined: (2R,3R)-1,1,4,4-tetra(naphthalen-1-yl)butane-1,2,3,4-tetraol; (2R,3R)-1,1,4,4-tetra(naphthalen-2-yl)butane-1,2,3,4-tetraol; (2R,3R)-1,1,4,4-tetra(p-anisyl)butane-1,2,3,4-tetraol; (2R,3R)-1,1,4,4-tetra(p-tolyl)butane-1,2,3,4-tetraol; (2R,3R)-1,1,4,4-tetra(m-tolyl)butane-1,2,3,4-tetraol and; (2R,3R)-1,1,4,4-tetra(o-tolyl)butane-1,2,3,4-tetraol.
- Full Text:
- Date Issued: 2015
Chemical constituents and biological studies of Tagetes minuta L. and Rauvolfia caffra Sond
- Authors: Mlala, Sithenkosi
- Date: 2015
- Language: English
- Type: Thesis , Masters , MSc (Organic Chemistry)
- Identifier: vital:11358 , http://hdl.handle.net/10353/d1021325
- Description: Consequently, specific parts or the whole plant can be used for various treatments. The aim of this study was to extract, isolate and characterize the biologically active volatile and non-volatile compounds from Tagetes minuta and Rauvolfia caffra respectively. Tagetes minuta plant was considered for extraction of essential oils using hydrodistillation method. Cis-β-ocimene (38.03%), caryophyllene oxide (18.04%), alloocimene (25.35 %), isopropyl tetradecanoate (17.02 %), cis-ocimene (38.14%) and trans-β-ocimene (37.03%) were the major components of essential oil analyzed from fresh stem, dried stem, fresh leaf, dried leaf, fresh flower and dried flower respectively. The volatile compounds were identified by Gas Chromatography-Mass Spectrometry (GC-MS) and Gas Chromatography (GC). Essential oil of dried stem leaf and flower parts of T. minuta exhibit antioxidant activity as demonstrated by the DPPH and FRAP bioassays. Crude extracts were extracted from R. caffra stem bark using sequence of solvents namely n-hexane, dichloromethane, ethyl acetate, methanol and ethanol. A white powder, a β-sitosterol (non-volatile compound) was isolated by column chromatography from ethyl acetate fractions of R. caffra stem bark and identified on various spectroscopic techniques such as FTIR and (1D and 2D) NMR. Melting point was also determined to be a sharp 129-130 ºC. DCM, EA, MetOH and EtOH fractions as well as β-Sitosterol (compound SM/01), showed antioxidant activity when tested on DPPH, FRAP, total phenolic and flavonoid bioassays. This antioxidant activity might be due to the presence of hydroxyl groups in the compound and crude fractions. On the other hand, T. minuta’s essential oil showed high antioxidant activity when evaluated on the DPPH and FRAP bioassays, which can be attributed to the presence of oxygenated monoterpenes and sesquiterpenes known to act as free radical scavenging and reducing agents. The use of R. caffra stem bark extracts against hypertension and other diseases by traditional healers could be attributed to the presence of phytochemicals (polyphenols and flavonoids) with known health benefits. Thus, it is recommended that the plant should be exploited further using modern techniques involving separation and purification of compounds that can be used for drug formulation. This study supports the use of T. minuta and R. caffra as the potential natural antioxidant source to manage various diseases including hypertension.
- Full Text:
- Date Issued: 2015
- Authors: Mlala, Sithenkosi
- Date: 2015
- Language: English
- Type: Thesis , Masters , MSc (Organic Chemistry)
- Identifier: vital:11358 , http://hdl.handle.net/10353/d1021325
- Description: Consequently, specific parts or the whole plant can be used for various treatments. The aim of this study was to extract, isolate and characterize the biologically active volatile and non-volatile compounds from Tagetes minuta and Rauvolfia caffra respectively. Tagetes minuta plant was considered for extraction of essential oils using hydrodistillation method. Cis-β-ocimene (38.03%), caryophyllene oxide (18.04%), alloocimene (25.35 %), isopropyl tetradecanoate (17.02 %), cis-ocimene (38.14%) and trans-β-ocimene (37.03%) were the major components of essential oil analyzed from fresh stem, dried stem, fresh leaf, dried leaf, fresh flower and dried flower respectively. The volatile compounds were identified by Gas Chromatography-Mass Spectrometry (GC-MS) and Gas Chromatography (GC). Essential oil of dried stem leaf and flower parts of T. minuta exhibit antioxidant activity as demonstrated by the DPPH and FRAP bioassays. Crude extracts were extracted from R. caffra stem bark using sequence of solvents namely n-hexane, dichloromethane, ethyl acetate, methanol and ethanol. A white powder, a β-sitosterol (non-volatile compound) was isolated by column chromatography from ethyl acetate fractions of R. caffra stem bark and identified on various spectroscopic techniques such as FTIR and (1D and 2D) NMR. Melting point was also determined to be a sharp 129-130 ºC. DCM, EA, MetOH and EtOH fractions as well as β-Sitosterol (compound SM/01), showed antioxidant activity when tested on DPPH, FRAP, total phenolic and flavonoid bioassays. This antioxidant activity might be due to the presence of hydroxyl groups in the compound and crude fractions. On the other hand, T. minuta’s essential oil showed high antioxidant activity when evaluated on the DPPH and FRAP bioassays, which can be attributed to the presence of oxygenated monoterpenes and sesquiterpenes known to act as free radical scavenging and reducing agents. The use of R. caffra stem bark extracts against hypertension and other diseases by traditional healers could be attributed to the presence of phytochemicals (polyphenols and flavonoids) with known health benefits. Thus, it is recommended that the plant should be exploited further using modern techniques involving separation and purification of compounds that can be used for drug formulation. This study supports the use of T. minuta and R. caffra as the potential natural antioxidant source to manage various diseases including hypertension.
- Full Text:
- Date Issued: 2015
Visualisation of PF firewall logs using open source
- Authors: Coetzee, Dirk
- Date: 2015
- Subjects: Open source software -- South Africa , Firewalls (Computer security) -- South Africa , Data logging -- South Africa , Data integrity -- South Africa , Data protection -- South Africa , Computer crimes -- South Africa , Hacktivism
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4719 , http://hdl.handle.net/10962/d1018552
- Description: If you cannot measure, you cannot manage. This is an age old saying, but still very true, especially within the current South African cybercrime scene and the ever-growing Internet footprint. Due to the significant increase in cybercrime across the globe, information security specialists are starting to see the intrinsic value of logs that can ‘tell a story’. Logs do not only tell a story, but also provide a tool to measure a normally dark force within an organisation. The collection of current logs from installed systems, operating systems and devices is imperative in the event of a hacking attempt, data leak or even data theft, whether the attempt is successful or unsuccessful. No logs mean no evidence, and in many cases not even the opportunity to find the mistake or fault in the organisation’s defence systems. Historically, it remains difficult to choose what logs are required by your organization. A number of questions should be considered: should a centralised or decentralised approach for collecting these logs be followed or a combination of both? How many events will be collected, how much additional bandwidth will be required and will the log collection be near real time? How long must the logs be saved and what if any hashing and encryption (integrity of data) should be used? Lastly, what system must be used to correlate, analyse, and make alerts and reports available? This thesis will address these myriad questions, examining the current lack of log analysis, practical implementations in modern organisation, and also how a need for the latter can be fulfilled by means of a basic approach. South African organizations must use technology that is at hand in order to know what electronic data are sent in and out of their organizations network. Concentrating only on FreeBSD PF firewall logs, it is demonstrated within this thesis the excellent results are possible when logs are collected to obtain a visual display of what data is traversing the corporate network and which parts of this data are posing a threat to the corporate network. This threat is easily determined via a visual interpretation of statistical outliers. This thesis aims to show that in the field of corporate data protection, if you can measure, you can manage.
- Full Text:
- Date Issued: 2015
- Authors: Coetzee, Dirk
- Date: 2015
- Subjects: Open source software -- South Africa , Firewalls (Computer security) -- South Africa , Data logging -- South Africa , Data integrity -- South Africa , Data protection -- South Africa , Computer crimes -- South Africa , Hacktivism
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4719 , http://hdl.handle.net/10962/d1018552
- Description: If you cannot measure, you cannot manage. This is an age old saying, but still very true, especially within the current South African cybercrime scene and the ever-growing Internet footprint. Due to the significant increase in cybercrime across the globe, information security specialists are starting to see the intrinsic value of logs that can ‘tell a story’. Logs do not only tell a story, but also provide a tool to measure a normally dark force within an organisation. The collection of current logs from installed systems, operating systems and devices is imperative in the event of a hacking attempt, data leak or even data theft, whether the attempt is successful or unsuccessful. No logs mean no evidence, and in many cases not even the opportunity to find the mistake or fault in the organisation’s defence systems. Historically, it remains difficult to choose what logs are required by your organization. A number of questions should be considered: should a centralised or decentralised approach for collecting these logs be followed or a combination of both? How many events will be collected, how much additional bandwidth will be required and will the log collection be near real time? How long must the logs be saved and what if any hashing and encryption (integrity of data) should be used? Lastly, what system must be used to correlate, analyse, and make alerts and reports available? This thesis will address these myriad questions, examining the current lack of log analysis, practical implementations in modern organisation, and also how a need for the latter can be fulfilled by means of a basic approach. South African organizations must use technology that is at hand in order to know what electronic data are sent in and out of their organizations network. Concentrating only on FreeBSD PF firewall logs, it is demonstrated within this thesis the excellent results are possible when logs are collected to obtain a visual display of what data is traversing the corporate network and which parts of this data are posing a threat to the corporate network. This threat is easily determined via a visual interpretation of statistical outliers. This thesis aims to show that in the field of corporate data protection, if you can measure, you can manage.
- Full Text:
- Date Issued: 2015
Invariant control systems and sub-Riemannian structures on lie groups: equivalence and isometries
- Authors: Biggs, Rory
- Date: 2015
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/64815 , vital:28607
- Description: In this thesis we consider invariant optimal control problems and invariant sub-Riemannian structures on Lie groups. Primarily, we are concerned with the equivalence and classification of problems (resp. structures). In the first chapter, both the class of invariant optimal control problems and the class of invariant sub-Riemannian structures are organised as categories. The latter category is shown to be functorially equivalent to a subcategory of the former category. Via the Pontryagin Maximum Principle, we associate to each invariant optimal control problem (resp. invariant sub-Riemannian structure) a quadratic Hamilton-Poisson system on the associated Lie-Poisson space. These Hamiltonian systems are also organised as a category and hence the Pontryagin lift is realised as a contravariant functor. Basic properties of these categories are investigated. The rest of this thesis is concerned with the classification (and investigation) of certain subclasses of structures and systems. In the second chapter, the homogeneous positive semidefinite quadratic Hamilton-Poisson systems on three-dimensional Lie-Poisson spaces are classified up to compatibility with a linear isomorphism; a list of 23 normal forms is exhibited. In the third chapter, we classify the invariant sub-Riemannian structures in three dimensions and calculate the isometry group for each normal form. By comparing our results with known results, we show that most isometries (in three dimensions) are in fact the composition of a left translation and a Lie group isomorphism. In the fourth and last chapter of this thesis, we classify the sub-Riemannian and Riemannian structures on the (2n + 1)-dimensional Heisenberg groups. Furthermore, we find the isometry group and geodesics of each normal form.
- Full Text:
- Date Issued: 2015
- Authors: Biggs, Rory
- Date: 2015
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/64815 , vital:28607
- Description: In this thesis we consider invariant optimal control problems and invariant sub-Riemannian structures on Lie groups. Primarily, we are concerned with the equivalence and classification of problems (resp. structures). In the first chapter, both the class of invariant optimal control problems and the class of invariant sub-Riemannian structures are organised as categories. The latter category is shown to be functorially equivalent to a subcategory of the former category. Via the Pontryagin Maximum Principle, we associate to each invariant optimal control problem (resp. invariant sub-Riemannian structure) a quadratic Hamilton-Poisson system on the associated Lie-Poisson space. These Hamiltonian systems are also organised as a category and hence the Pontryagin lift is realised as a contravariant functor. Basic properties of these categories are investigated. The rest of this thesis is concerned with the classification (and investigation) of certain subclasses of structures and systems. In the second chapter, the homogeneous positive semidefinite quadratic Hamilton-Poisson systems on three-dimensional Lie-Poisson spaces are classified up to compatibility with a linear isomorphism; a list of 23 normal forms is exhibited. In the third chapter, we classify the invariant sub-Riemannian structures in three dimensions and calculate the isometry group for each normal form. By comparing our results with known results, we show that most isometries (in three dimensions) are in fact the composition of a left translation and a Lie group isomorphism. In the fourth and last chapter of this thesis, we classify the sub-Riemannian and Riemannian structures on the (2n + 1)-dimensional Heisenberg groups. Furthermore, we find the isometry group and geodesics of each normal form.
- Full Text:
- Date Issued: 2015
Characterization of polychlorinated biphenyl residues in the North End lake and Port Elizabeth harbour, South Africa
- Authors: Kampire, Edwige
- Date: 2015
- Subjects: Marine pollution -- South Africa -- Port Elizabeth , Estuarine pollution -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/7903 , vital:24320
- Description: Persistent organic pollutants (POPs), including polychlorinated biphenyls (PCBs) are widespread in aquatic systems, they can bioaccumulate in the tissues of aquatic organisms, especially fish as they occupy a position near the top of the aquatic food web. PCBs are among the most toxic substances and have been shown to cause many adverse effects to humans and wildlife. High health risks are associated with populations that follow a diet high in fat content such as fish and shellfish in which PCBs bioaccumulate. Given the importance of industries and the potential health concerns of exposure to PCBs, the lack of information on environmental levels of PCBs in South Africa (SA) is significant and concerning. Less attention has been directed to analysis of PCBs in the South African environments due to high cost and lack of appropriate equipment. This study was the first conducted in order to assess the levels of PCBs in the environment of Nelson Mandela Bay Municipality (Port Elizabeth). The research was directed at determining the PCB levels in water, sediments, fish and mussels collected in the Nelson Mandela Bay Municipality. The sampling sites, North End Lake (NEL) and Port Elizabeth Harbour (PEH) were selected based on their location and the importance of activities taking place in these areas. In total 456 samples of water (dissolved and particulate phases), sediments, mussels and tissues of fish were analysed. Suitable analytical methods were based on the equipment and materials available at the Nelson Mandela Metropolitan University. Gas chromatography-mass spectrometry (GC/MS) was used to quantify PCBs in the samples using the internal standard method. Six indicator congeners (PCB nos. 28, 52, 101, 138, 153, 180) were chosen because they are mainly present in most PCB mixtures in environmental samples and they are recommended for regular monitoring. These congeners represent about 50% of the total non-dioxin like (NDL) PCBs in food. All these congeners were detected in the samples analysed. The total PCB concentrations in the sediments from the NEL and PEH ranged from 1.60 to 3.06 and from 0.56 to 2.35 ng g-1 dry weight, respectively. The concentrations of total PCBs in Mytilus galloprovincialis ranged from 14.48 to 21.37 ng g-1 wet weight and from 20.84 to 31.34 ng g-1 wet weight in Perna perna. Total PCBs in water ranged from 0.18 to 0.355 ng L-1. The concentrations of total PCBs in the liver, gonads, gills and muscle were 95.69, 57.49, 44.63, 34.14 ng g-1 lipid weight in Cyprinus carpio and 119.73, 59.21, 49.78, 34.63 ng g-1 in Oreochromis mossambicus, respectively. Fish liver was the most contaminated organ due to its high lipid content compared to other parts of fish analysed. The NEL was found to be more contaminated than the PEH. The main potential sources of PCB pollutants in both areas of this study are industrial and municipal discharges. The NEL is surrounded by many industries and serves as a potential pollutant sink due to wastewater and inflow entering into this lake. Four 0.227 kg meals of the edible part of fish (muscle) per month were recommended based on the non-cancer health endpoint and one 0.227 kg meal per month was recommended based on the cancer health endpoint. This research contributed to notify the public and relevant governmental departments on the PCB pollution status of sediments, water and aquatic life in the PEH and NEL.
- Full Text:
- Date Issued: 2015
- Authors: Kampire, Edwige
- Date: 2015
- Subjects: Marine pollution -- South Africa -- Port Elizabeth , Estuarine pollution -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/7903 , vital:24320
- Description: Persistent organic pollutants (POPs), including polychlorinated biphenyls (PCBs) are widespread in aquatic systems, they can bioaccumulate in the tissues of aquatic organisms, especially fish as they occupy a position near the top of the aquatic food web. PCBs are among the most toxic substances and have been shown to cause many adverse effects to humans and wildlife. High health risks are associated with populations that follow a diet high in fat content such as fish and shellfish in which PCBs bioaccumulate. Given the importance of industries and the potential health concerns of exposure to PCBs, the lack of information on environmental levels of PCBs in South Africa (SA) is significant and concerning. Less attention has been directed to analysis of PCBs in the South African environments due to high cost and lack of appropriate equipment. This study was the first conducted in order to assess the levels of PCBs in the environment of Nelson Mandela Bay Municipality (Port Elizabeth). The research was directed at determining the PCB levels in water, sediments, fish and mussels collected in the Nelson Mandela Bay Municipality. The sampling sites, North End Lake (NEL) and Port Elizabeth Harbour (PEH) were selected based on their location and the importance of activities taking place in these areas. In total 456 samples of water (dissolved and particulate phases), sediments, mussels and tissues of fish were analysed. Suitable analytical methods were based on the equipment and materials available at the Nelson Mandela Metropolitan University. Gas chromatography-mass spectrometry (GC/MS) was used to quantify PCBs in the samples using the internal standard method. Six indicator congeners (PCB nos. 28, 52, 101, 138, 153, 180) were chosen because they are mainly present in most PCB mixtures in environmental samples and they are recommended for regular monitoring. These congeners represent about 50% of the total non-dioxin like (NDL) PCBs in food. All these congeners were detected in the samples analysed. The total PCB concentrations in the sediments from the NEL and PEH ranged from 1.60 to 3.06 and from 0.56 to 2.35 ng g-1 dry weight, respectively. The concentrations of total PCBs in Mytilus galloprovincialis ranged from 14.48 to 21.37 ng g-1 wet weight and from 20.84 to 31.34 ng g-1 wet weight in Perna perna. Total PCBs in water ranged from 0.18 to 0.355 ng L-1. The concentrations of total PCBs in the liver, gonads, gills and muscle were 95.69, 57.49, 44.63, 34.14 ng g-1 lipid weight in Cyprinus carpio and 119.73, 59.21, 49.78, 34.63 ng g-1 in Oreochromis mossambicus, respectively. Fish liver was the most contaminated organ due to its high lipid content compared to other parts of fish analysed. The NEL was found to be more contaminated than the PEH. The main potential sources of PCB pollutants in both areas of this study are industrial and municipal discharges. The NEL is surrounded by many industries and serves as a potential pollutant sink due to wastewater and inflow entering into this lake. Four 0.227 kg meals of the edible part of fish (muscle) per month were recommended based on the non-cancer health endpoint and one 0.227 kg meal per month was recommended based on the cancer health endpoint. This research contributed to notify the public and relevant governmental departments on the PCB pollution status of sediments, water and aquatic life in the PEH and NEL.
- Full Text:
- Date Issued: 2015
Application of Baylis-Hillman methodology in the synthesis of HIV-1 enzyme inhibitors
- Authors: Manyeruke, Meloddy Hlatini
- Date: 2015
- Subjects: HIV infections , Enzyme inhibitors , AZT (Drug) , Bioconjugates
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4540 , http://hdl.handle.net/10962/d1017920
- Description: The application of Baylis-Hillman methodology has afforded access to a range of β-hydroxypropionate ester-AZT conjugates as potential dual-action HIV-1 IN/RT inhibitors. Two families comprising a total of nine β-hydroxypropionate ester-AZT conjugates were synthesised. The first family was accessed using O-benzylated salicylaldehydes and methyl acrylate and the second from unprotected salicylaldehydes using tert-butyl acrylate as the activated alkene. Spectroscopic methods were employed to fully characterize the compounds. Propargylation of the respective Baylis-Hillman adducts was achieved via conjugate addition of propargylamine. The resulting products were then employed in Cu(I)-catalysed “click” reactions with azidothymidine (AZT) to yield the desired β-hydroxypropionate ester-AZT conjugates. Exploratory studies were also conducted to access 4-hydroxycoumarins from Baylis-Hillman derived adducts and to construct customized chiral Baylis-Hillman reaction sites. Many 4- hydroxycoumarins are known to exhibit a wide range of biological activities, and extending Baylis-Hillman methodology to access these systems is an important challenge. Two approaches were investigated. The first involved the formation of a 4-phthalimidocoumarin, aromatisation and hydrolysis of which was expected to lead to the 4-hydroxycoumarin target. The second, a variation of the first, involved the use of 4-(chrolomethyl)coumarin intermediates. Unfortunately, while various intermediates were prepared and characterised, neither approach led ultimately to the desired targets. N-substituted borneol-10-sulfonamides were constructed from camphor-10- sulfonyl chloride as chiral Baylis-Hillman reaction sites. In a preliminary study, however, none of the N-substituted borneol-10-sulfonamides exhibited Baylis-Hillman catalytic activity.
- Full Text:
- Date Issued: 2015
- Authors: Manyeruke, Meloddy Hlatini
- Date: 2015
- Subjects: HIV infections , Enzyme inhibitors , AZT (Drug) , Bioconjugates
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4540 , http://hdl.handle.net/10962/d1017920
- Description: The application of Baylis-Hillman methodology has afforded access to a range of β-hydroxypropionate ester-AZT conjugates as potential dual-action HIV-1 IN/RT inhibitors. Two families comprising a total of nine β-hydroxypropionate ester-AZT conjugates were synthesised. The first family was accessed using O-benzylated salicylaldehydes and methyl acrylate and the second from unprotected salicylaldehydes using tert-butyl acrylate as the activated alkene. Spectroscopic methods were employed to fully characterize the compounds. Propargylation of the respective Baylis-Hillman adducts was achieved via conjugate addition of propargylamine. The resulting products were then employed in Cu(I)-catalysed “click” reactions with azidothymidine (AZT) to yield the desired β-hydroxypropionate ester-AZT conjugates. Exploratory studies were also conducted to access 4-hydroxycoumarins from Baylis-Hillman derived adducts and to construct customized chiral Baylis-Hillman reaction sites. Many 4- hydroxycoumarins are known to exhibit a wide range of biological activities, and extending Baylis-Hillman methodology to access these systems is an important challenge. Two approaches were investigated. The first involved the formation of a 4-phthalimidocoumarin, aromatisation and hydrolysis of which was expected to lead to the 4-hydroxycoumarin target. The second, a variation of the first, involved the use of 4-(chrolomethyl)coumarin intermediates. Unfortunately, while various intermediates were prepared and characterised, neither approach led ultimately to the desired targets. N-substituted borneol-10-sulfonamides were constructed from camphor-10- sulfonyl chloride as chiral Baylis-Hillman reaction sites. In a preliminary study, however, none of the N-substituted borneol-10-sulfonamides exhibited Baylis-Hillman catalytic activity.
- Full Text:
- Date Issued: 2015
Investigation into the characteristics and possible applications of biomass gasification by-products from a downdraft gasifier system
- Authors: Melapi, Aviwe
- Date: 2015
- Subjects: Biomass gasification -- South Africa -- Eastern Cape , Renewable energy sources -- South Africa -- Eastern Cape , Biomass energy -- South Africa -- Eastern Cape , Crop residue management -- South Africa -- Eastern Cape , Coal gasification -- South Africa -- Eastern Cape , Lignocellulose -- Biodegradation -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc (Chemistry)
- Identifier: vital:11348 , http://hdl.handle.net/10353/d1020174 , Biomass gasification -- South Africa -- Eastern Cape , Renewable energy sources -- South Africa -- Eastern Cape , Biomass energy -- South Africa -- Eastern Cape , Crop residue management -- South Africa -- Eastern Cape , Coal gasification -- South Africa -- Eastern Cape , Lignocellulose -- Biodegradation -- South Africa -- Eastern Cape
- Description: Biomass gasification has attracted the interest of researchers because it produces zero carbon to the atmosphere. This technology does not only produce syngas but also the byproducts which can be used for various application depending on quality.The study conducted at Melani village in Alice in the Eastern Cape of South Africa was aimed at investigating the possible applications of the gasification byproducts instead of being thrown away. Pine wood was employed as the parent feedstock material for the gasifier. Biomass gasification by-products were then collected for further analysis. The studied by-products included tar(condensate), char, soot and resin. These materials were also blended to produce strong materials.The essence of the blending was to generate ideal material that is strong but light at the same time.The elemental analysis of the samples performed by CHNS analyser revealed that carbon element is in large quantities in all samples. The FTIR spectra showed almost similar results for all the studied samples, since the samples are end products of lignocellulosegasification. SEM gave the sticky images of resin as well as porous char structures. Char showed a higher heating value of 35.37MJ/Kg when compared to other by-products samples.
- Full Text:
- Date Issued: 2015
- Authors: Melapi, Aviwe
- Date: 2015
- Subjects: Biomass gasification -- South Africa -- Eastern Cape , Renewable energy sources -- South Africa -- Eastern Cape , Biomass energy -- South Africa -- Eastern Cape , Crop residue management -- South Africa -- Eastern Cape , Coal gasification -- South Africa -- Eastern Cape , Lignocellulose -- Biodegradation -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc (Chemistry)
- Identifier: vital:11348 , http://hdl.handle.net/10353/d1020174 , Biomass gasification -- South Africa -- Eastern Cape , Renewable energy sources -- South Africa -- Eastern Cape , Biomass energy -- South Africa -- Eastern Cape , Crop residue management -- South Africa -- Eastern Cape , Coal gasification -- South Africa -- Eastern Cape , Lignocellulose -- Biodegradation -- South Africa -- Eastern Cape
- Description: Biomass gasification has attracted the interest of researchers because it produces zero carbon to the atmosphere. This technology does not only produce syngas but also the byproducts which can be used for various application depending on quality.The study conducted at Melani village in Alice in the Eastern Cape of South Africa was aimed at investigating the possible applications of the gasification byproducts instead of being thrown away. Pine wood was employed as the parent feedstock material for the gasifier. Biomass gasification by-products were then collected for further analysis. The studied by-products included tar(condensate), char, soot and resin. These materials were also blended to produce strong materials.The essence of the blending was to generate ideal material that is strong but light at the same time.The elemental analysis of the samples performed by CHNS analyser revealed that carbon element is in large quantities in all samples. The FTIR spectra showed almost similar results for all the studied samples, since the samples are end products of lignocellulosegasification. SEM gave the sticky images of resin as well as porous char structures. Char showed a higher heating value of 35.37MJ/Kg when compared to other by-products samples.
- Full Text:
- Date Issued: 2015
The electrical, structural and elemental analyis of degraded single junction amorphous silicon solar modules
- Osayemwenre, Gilbert Omorodion
- Authors: Osayemwenre, Gilbert Omorodion
- Date: 2015
- Subjects: Amorphous semiconductors Solar cells Silicon crystals
- Language: English
- Type: Thesis , Masters , Science
- Identifier: http://hdl.handle.net/10353/11674 , vital:39095
- Description: This study focuses on the degradation of solar cells due to localized heat. A decrease in optical absorbance represents a huge problem because of long-term solar cell degradation, decrease in absorption coefficient and a reduction in solar cell conversion efficiency. This decreases the photo-generating current hence reduces the effective efficiency of the solar device. As such the electrical output decreases, this research investigates the reduction in a-Si:H modules maximum power and its light absorption and correlates this with hot spot formation. Infrared Thermography was used for mapping of the module temperature profile, while IR flying meter software was used to analyze the hot spot centre. Fourier Transform Infrared Spectroscopy (FTIR) was used for absorption characterization. The study was undertaken during outdoor deployment of five PV modules. This method was chosen so as to deduce the practical effect of hot spot formation on the module’s absorption ability. The results show a direct correlation between localized heat and absorption degradation and structural degradation (damaged) in a-Si:H.
- Full Text:
- Date Issued: 2015
- Authors: Osayemwenre, Gilbert Omorodion
- Date: 2015
- Subjects: Amorphous semiconductors Solar cells Silicon crystals
- Language: English
- Type: Thesis , Masters , Science
- Identifier: http://hdl.handle.net/10353/11674 , vital:39095
- Description: This study focuses on the degradation of solar cells due to localized heat. A decrease in optical absorbance represents a huge problem because of long-term solar cell degradation, decrease in absorption coefficient and a reduction in solar cell conversion efficiency. This decreases the photo-generating current hence reduces the effective efficiency of the solar device. As such the electrical output decreases, this research investigates the reduction in a-Si:H modules maximum power and its light absorption and correlates this with hot spot formation. Infrared Thermography was used for mapping of the module temperature profile, while IR flying meter software was used to analyze the hot spot centre. Fourier Transform Infrared Spectroscopy (FTIR) was used for absorption characterization. The study was undertaken during outdoor deployment of five PV modules. This method was chosen so as to deduce the practical effect of hot spot formation on the module’s absorption ability. The results show a direct correlation between localized heat and absorption degradation and structural degradation (damaged) in a-Si:H.
- Full Text:
- Date Issued: 2015
Contributions to the study of a class of optimal control problems on the orthogonal groups SO(3) and SO(4)
- Authors: Adams, Ross Montague
- Date: 2015
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/64826 , vital:28608
- Description: In this thesis we investigate a class of invariant optimal control problems, and their associated quadratic Hamilton-Poisson systems, on the orthogonal groups SO(3) and SO(4). Specifically, we are concerned with the class of left-invariant control affine systems. We begin by classifying all cost-extended systems on SO(3) under cost equivalence. (Cost-extended systems are closely related to optimal control problems.) A classification of all quadratic Hamilton-Poisson systems on the (minus) Lie-Poisson space so(3)*, under affine equivalence, is also obtained. For the normal forms obtained in our classification (of Hamilton-Poisson systems) we investigate the (Lyapunov) stability nature of the equilibria using spectral and energy-Casimir methods. For a subclass of these systems, we obtain analytic expressions for the integral curves of the associated Hamiltonian vector fields in terms of (basic) Jacobi elliptic functions. The explicit relationship between the classification of cost-extended systems on SO(3) and the classification of quadratic Hamilton- Poisson systems on so(3)* is provided. On SO(4), a classification of all left-invariant control affine systems under L-equivalence is obtained. We then determine which of these representatives are controllable, thus obtaining a classification under detached feedback equivalence. We also obtain a partial classification of quadratic Hamilton-Poisson systems on the Lie-Poisson space so(4)*. An investigation of the stability nature of the equilibria for a subclass of these systems is also done. Several illustrative examples of optimal control problems on the orthogonal group SO(3) are provided. More specifically, we consider an optimal control problem corresponding to a representative of our classification (of cost-extended system) for each possible number of control inputs. For each of these problems, we obtain explicit expressions for the extremal trajectories on the homogeneous space S2 by projecting the extremal trajectories on the group SO(3). The examples provided show how our classifications of cost-extended systems and Hamilton-Poisson systems can be used to obtain the optimal controls and the extremal trajectories corresponding to a large class of optimal control problems on SO(3). An example of a four-input optimal control problem on SO(4) is also provided. This example is provided to show how the solutions of certain problems on SO(4) can be related to the solutions of certain optimal control problems on SO(3).
- Full Text:
- Date Issued: 2015
- Authors: Adams, Ross Montague
- Date: 2015
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/64826 , vital:28608
- Description: In this thesis we investigate a class of invariant optimal control problems, and their associated quadratic Hamilton-Poisson systems, on the orthogonal groups SO(3) and SO(4). Specifically, we are concerned with the class of left-invariant control affine systems. We begin by classifying all cost-extended systems on SO(3) under cost equivalence. (Cost-extended systems are closely related to optimal control problems.) A classification of all quadratic Hamilton-Poisson systems on the (minus) Lie-Poisson space so(3)*, under affine equivalence, is also obtained. For the normal forms obtained in our classification (of Hamilton-Poisson systems) we investigate the (Lyapunov) stability nature of the equilibria using spectral and energy-Casimir methods. For a subclass of these systems, we obtain analytic expressions for the integral curves of the associated Hamiltonian vector fields in terms of (basic) Jacobi elliptic functions. The explicit relationship between the classification of cost-extended systems on SO(3) and the classification of quadratic Hamilton- Poisson systems on so(3)* is provided. On SO(4), a classification of all left-invariant control affine systems under L-equivalence is obtained. We then determine which of these representatives are controllable, thus obtaining a classification under detached feedback equivalence. We also obtain a partial classification of quadratic Hamilton-Poisson systems on the Lie-Poisson space so(4)*. An investigation of the stability nature of the equilibria for a subclass of these systems is also done. Several illustrative examples of optimal control problems on the orthogonal group SO(3) are provided. More specifically, we consider an optimal control problem corresponding to a representative of our classification (of cost-extended system) for each possible number of control inputs. For each of these problems, we obtain explicit expressions for the extremal trajectories on the homogeneous space S2 by projecting the extremal trajectories on the group SO(3). The examples provided show how our classifications of cost-extended systems and Hamilton-Poisson systems can be used to obtain the optimal controls and the extremal trajectories corresponding to a large class of optimal control problems on SO(3). An example of a four-input optimal control problem on SO(4) is also provided. This example is provided to show how the solutions of certain problems on SO(4) can be related to the solutions of certain optimal control problems on SO(3).
- Full Text:
- Date Issued: 2015
The politics of interweaving performance cultures
- Authors: Krueger, Anton
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/225719 , vital:49252 , xlink:href="https://doi.org/10.1080/10137548.2015.1014170"
- Description: According to the former president of the International Federation of Theatre Research (IFTR), Brian Singleton, the study of ‘[i]nterculturalism as a practice and a theory gained currency with Richard Schechner’s anthropologically-inspired new discipline of performance studies’ (p. 79). Schechner’s new discipline led to the formation of the annual Performance Studies International (PSI) conferences, and earlier this year I attended the twentieth instalment in Shanghai, which was held under the rubric of ‘Tradition and the Avant-Garde’. One of the things which struck me was the extent to which the (relatively) newly economically empowered Chinese theatre makers were creating grand productions based on Western theatre traditions. For example, many of the presentations for delegates were based on Western texts (such as Hamlet, Miss Julie and even a play by Woody Allen). And yet these productions were performed in Mandarin, using purist Chinese forms, such as Beijing Opera. During the discussions there seemed to be an awkward defensiveness from some of the Chinese hosts who insisted they were not ‘copying’ Western theatre, but that they were using it to express a pure Chinese aesthetic. There were also other performances at the conference, such as a series of parables called Confucius Disciples, which told didactic tales with content very foreign to a Western audience. A visiting troupe from Bulgaria presented their own version of some of these parables, using a strongly East European aesthetic to convey a Chinese message. In this way, experiments with cultural forms and content were clearly foregrounded by the conference presentations.
- Full Text:
- Date Issued: 2015
- Authors: Krueger, Anton
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/225719 , vital:49252 , xlink:href="https://doi.org/10.1080/10137548.2015.1014170"
- Description: According to the former president of the International Federation of Theatre Research (IFTR), Brian Singleton, the study of ‘[i]nterculturalism as a practice and a theory gained currency with Richard Schechner’s anthropologically-inspired new discipline of performance studies’ (p. 79). Schechner’s new discipline led to the formation of the annual Performance Studies International (PSI) conferences, and earlier this year I attended the twentieth instalment in Shanghai, which was held under the rubric of ‘Tradition and the Avant-Garde’. One of the things which struck me was the extent to which the (relatively) newly economically empowered Chinese theatre makers were creating grand productions based on Western theatre traditions. For example, many of the presentations for delegates were based on Western texts (such as Hamlet, Miss Julie and even a play by Woody Allen). And yet these productions were performed in Mandarin, using purist Chinese forms, such as Beijing Opera. During the discussions there seemed to be an awkward defensiveness from some of the Chinese hosts who insisted they were not ‘copying’ Western theatre, but that they were using it to express a pure Chinese aesthetic. There were also other performances at the conference, such as a series of parables called Confucius Disciples, which told didactic tales with content very foreign to a Western audience. A visiting troupe from Bulgaria presented their own version of some of these parables, using a strongly East European aesthetic to convey a Chinese message. In this way, experiments with cultural forms and content were clearly foregrounded by the conference presentations.
- Full Text:
- Date Issued: 2015
A critical assessment of economic policies and their impact on entrepreneurship development in South Africa: a case of Khayelitsha Township in Cape Town
- Oduwole, Olusola https://orcid.org/0000-0002-1563-7392
- Authors: Oduwole, Olusola https://orcid.org/0000-0002-1563-7392
- Date: 2015
- Subjects: Entrepreneurship , Economic policy , Economic development -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/26302 , vital:65236
- Description: The complexity of the South African society due to past systematic exclusion of some communities from economic activities resulted in the triple challenge of poverty, inequality and unemployment. Although various economic policies had been developed since the advent of the democratic dispensation in 1994, these policies focused on levelling the economic environment, poverty alleviation and massive social security system. However, despite all the interventions, South Africa remains one of the most unequal societies in the world. This is profiled by the mushrooming of informal settlements around cities with job seekers and frequent protests by people who are impatient to experience improvement in their quality of life and who feel cheated out of their social contract. Advocacy from the governing party’s tripartite alliance towards a developmental state had placed more obligations on the government. This requires deliberate interventions through policies implementation to improve or at best alleviate the well-being of the citizenry. A survey conducted in the township of Khayelitsha to assess the impact of such economic policies on the development of entrepreneurship. Khayelitsha is one of South Africa’s largest townships, an informal settlement profiled by unemployment, poor infrastructure and unavailability of basic services. The study explored the entrepreneurial perception, start-up barriers, entrepreneurship climate, and general cultural factors relating to the environment of entrepreneurship development. The results reveal that despite the various economic policies, high level of unwillingness of citizens towards entrepreneurial activity and business venture is rife notwithstanding the high level of unemployment and poverty. The antidote to these challenges would be a rapid entrepreneurship drive among people most affected that would cause them to mind their own business” and become “masters of their own destinies. Given the complexity and massiveness of the challenges, the conclusion shows that a pragmatic solution is required. Therefore, the emancipation of entrepreneurship development in South Africa townships needs attention. The recommended solution is a pragmatic and innovative strategy based on the acronyms NEEDS HELP which stand for Neighbourhood Enhancement and Environmental Development Strategy and Holistic Entrepreneurial Lifestyle Programme. , Thesis (PhD) -- Faculty of Management and Commerce, 2015
- Full Text:
- Date Issued: 2015
- Authors: Oduwole, Olusola https://orcid.org/0000-0002-1563-7392
- Date: 2015
- Subjects: Entrepreneurship , Economic policy , Economic development -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/26302 , vital:65236
- Description: The complexity of the South African society due to past systematic exclusion of some communities from economic activities resulted in the triple challenge of poverty, inequality and unemployment. Although various economic policies had been developed since the advent of the democratic dispensation in 1994, these policies focused on levelling the economic environment, poverty alleviation and massive social security system. However, despite all the interventions, South Africa remains one of the most unequal societies in the world. This is profiled by the mushrooming of informal settlements around cities with job seekers and frequent protests by people who are impatient to experience improvement in their quality of life and who feel cheated out of their social contract. Advocacy from the governing party’s tripartite alliance towards a developmental state had placed more obligations on the government. This requires deliberate interventions through policies implementation to improve or at best alleviate the well-being of the citizenry. A survey conducted in the township of Khayelitsha to assess the impact of such economic policies on the development of entrepreneurship. Khayelitsha is one of South Africa’s largest townships, an informal settlement profiled by unemployment, poor infrastructure and unavailability of basic services. The study explored the entrepreneurial perception, start-up barriers, entrepreneurship climate, and general cultural factors relating to the environment of entrepreneurship development. The results reveal that despite the various economic policies, high level of unwillingness of citizens towards entrepreneurial activity and business venture is rife notwithstanding the high level of unemployment and poverty. The antidote to these challenges would be a rapid entrepreneurship drive among people most affected that would cause them to mind their own business” and become “masters of their own destinies. Given the complexity and massiveness of the challenges, the conclusion shows that a pragmatic solution is required. Therefore, the emancipation of entrepreneurship development in South Africa townships needs attention. The recommended solution is a pragmatic and innovative strategy based on the acronyms NEEDS HELP which stand for Neighbourhood Enhancement and Environmental Development Strategy and Holistic Entrepreneurial Lifestyle Programme. , Thesis (PhD) -- Faculty of Management and Commerce, 2015
- Full Text:
- Date Issued: 2015
Structure of the nucleus ¹¹⁴Sn using gamma-ray coincidence data
- Authors: Oates, Sean Benjamin
- Date: 2015
- Subjects: High spin physics , Nuclear structure , Nuclear shell theory , Neutron counters , Decay schemes (Radioactivity) , Coincidence circuits , Collective excitations , Anisotropy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5562 , http://hdl.handle.net/10962/d1019870
- Full Text:
- Date Issued: 2015
- Authors: Oates, Sean Benjamin
- Date: 2015
- Subjects: High spin physics , Nuclear structure , Nuclear shell theory , Neutron counters , Decay schemes (Radioactivity) , Coincidence circuits , Collective excitations , Anisotropy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5562 , http://hdl.handle.net/10962/d1019870
- Full Text:
- Date Issued: 2015