Ruthenium sulphide nanoparticles derived from tri-dithiocarbamato ruthenium (III) complexes : synthesis, optical and structural studies
- Authors: Mbese, Johannes Zanoxolo
- Date: 2017
- Subjects: Nanoparticles Ruthenium compounds
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/15420 , vital:40406
- Description: The present Thesis pioneer the application of single-source molecular precursor method for the synthesis of ruthenium sulfide nanoparticles using a series of novel self-prepared single-source molecular precursors. The preparation of precursors involved the design and synthesis of compounds containing all the desired elements required within the coordination compound. Good precursors are tailored to give reproducible, clean decomposition at moderate temperatures, leading to high quality, defect free, mono-dispersed nanoparticles. Nine (9) homonuclear tris-dithiocarbamato ruthenium(III) complexes, [Ru(S2CNR2)3] were prepared from a stoichiometric reaction of RuCl3·H2O with self-prepared dithiocarbamate ligands at room temperature in a molar ratio of Ru3+: Ligand of 1:3. Dithiocarbamate ligands were derived from a stoichiometric reaction of carbon disulfide with (aniline, N-allylmethylamine, p-toluidine, p-anisidine, N-ethyl-m-toluidine, piperidine, morpholine, di-isopropylamine, and diallylamine) in the presence of concentrated ammonia or potassium hydroxide in ice cold bath. The dithiocarbamate ligands and complexes were characterized by elemental analyses, UV-Vis, Fourier transform infrared spectroscopy (FTIR), 1H- and 13C-NMR spectroscopy. Thermogravimetric analyses (TGA) was used to study the decomposition profiles of the precursor complexes. The results obtained from the TGA of precursors showed that the complexes decompose to ruthenium sulfide nanoparticles. The FTIR spectra of the ligands revealed prominent strong absorption bands ascribed to v(N-H) stretching vibrations and also confirm the bidentate coordination of the dithiocarbamate ligands. Ruthenium(III) complexes show absorption spectra in the visible region that exhibit bands attributed to n → π* electronic transitions located on the sulfur atoms located in the S–C–S and N–C–S chromophores of the bidentate dithiocarbamate ligands respectively. The absorption spectra also confirmed the geometry of ruthenium(III) complexes to be octahedral. The proposed structures of dithiocarbamate ligands and ruthenium(III) complexes were confirmed by the 1H- and 13C-NMR. The complexes were used as single-source molecular precursors for the synthesis of ruthenium sulfide nanoparticles. The structural and optical properties were studied using transmission electron microscope (TEM), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), UV-Vis absorption and photoluminescence (PL) spectra. FTIR revealed that Ru2S3 nanoparticles are capped through the interaction of the –NH2 group of hexadecylamine HDA adsorbed on the surfaces of nanoparticles and it also showed that oleic acid (OA) is acting as both coordinating stabilizing surfactant and capping agent. The XRD confirmed the successful formation of Ru2S3 nanoparticles induced by the thermal decomposition of series of [Ru(S2CNR2)3] complexes. The diffraction peaks: 2θ = 29.43, 40.54, 49.33, 51.86, 61.92, and 75.94 were assign the Miler indices (hkl) to be (111), (211), (220), (300), (222) and (330) reflections, respectively, and were found to be in agreement with a cubic crystal structure reported in database file of (JCPDS 19-1107). The particle sizes estimated from Scherer's equation were found in a range between 2.5 and 4.9 nm. EDS spectra reveal that the prepared nanoparticles are mainly composed of Ru and S, confirming the presence of Ru2S3 nanoparticles in cubic phase. The inner morphology of nanoparticles was obtained by transmission electron microscopy (TEM) and most nanoparticles had narrow particle size distribution characterized by an average diameter of 8.45 nm with a standard deviation of 1.6 nm. The optical band gap (Eg) determined from Tauc plot was found in the range (3.44 to 4.18 eV) values.
- Full Text:
- Date Issued: 2017
- Authors: Mbese, Johannes Zanoxolo
- Date: 2017
- Subjects: Nanoparticles Ruthenium compounds
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/15420 , vital:40406
- Description: The present Thesis pioneer the application of single-source molecular precursor method for the synthesis of ruthenium sulfide nanoparticles using a series of novel self-prepared single-source molecular precursors. The preparation of precursors involved the design and synthesis of compounds containing all the desired elements required within the coordination compound. Good precursors are tailored to give reproducible, clean decomposition at moderate temperatures, leading to high quality, defect free, mono-dispersed nanoparticles. Nine (9) homonuclear tris-dithiocarbamato ruthenium(III) complexes, [Ru(S2CNR2)3] were prepared from a stoichiometric reaction of RuCl3·H2O with self-prepared dithiocarbamate ligands at room temperature in a molar ratio of Ru3+: Ligand of 1:3. Dithiocarbamate ligands were derived from a stoichiometric reaction of carbon disulfide with (aniline, N-allylmethylamine, p-toluidine, p-anisidine, N-ethyl-m-toluidine, piperidine, morpholine, di-isopropylamine, and diallylamine) in the presence of concentrated ammonia or potassium hydroxide in ice cold bath. The dithiocarbamate ligands and complexes were characterized by elemental analyses, UV-Vis, Fourier transform infrared spectroscopy (FTIR), 1H- and 13C-NMR spectroscopy. Thermogravimetric analyses (TGA) was used to study the decomposition profiles of the precursor complexes. The results obtained from the TGA of precursors showed that the complexes decompose to ruthenium sulfide nanoparticles. The FTIR spectra of the ligands revealed prominent strong absorption bands ascribed to v(N-H) stretching vibrations and also confirm the bidentate coordination of the dithiocarbamate ligands. Ruthenium(III) complexes show absorption spectra in the visible region that exhibit bands attributed to n → π* electronic transitions located on the sulfur atoms located in the S–C–S and N–C–S chromophores of the bidentate dithiocarbamate ligands respectively. The absorption spectra also confirmed the geometry of ruthenium(III) complexes to be octahedral. The proposed structures of dithiocarbamate ligands and ruthenium(III) complexes were confirmed by the 1H- and 13C-NMR. The complexes were used as single-source molecular precursors for the synthesis of ruthenium sulfide nanoparticles. The structural and optical properties were studied using transmission electron microscope (TEM), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), UV-Vis absorption and photoluminescence (PL) spectra. FTIR revealed that Ru2S3 nanoparticles are capped through the interaction of the –NH2 group of hexadecylamine HDA adsorbed on the surfaces of nanoparticles and it also showed that oleic acid (OA) is acting as both coordinating stabilizing surfactant and capping agent. The XRD confirmed the successful formation of Ru2S3 nanoparticles induced by the thermal decomposition of series of [Ru(S2CNR2)3] complexes. The diffraction peaks: 2θ = 29.43, 40.54, 49.33, 51.86, 61.92, and 75.94 were assign the Miler indices (hkl) to be (111), (211), (220), (300), (222) and (330) reflections, respectively, and were found to be in agreement with a cubic crystal structure reported in database file of (JCPDS 19-1107). The particle sizes estimated from Scherer's equation were found in a range between 2.5 and 4.9 nm. EDS spectra reveal that the prepared nanoparticles are mainly composed of Ru and S, confirming the presence of Ru2S3 nanoparticles in cubic phase. The inner morphology of nanoparticles was obtained by transmission electron microscopy (TEM) and most nanoparticles had narrow particle size distribution characterized by an average diameter of 8.45 nm with a standard deviation of 1.6 nm. The optical band gap (Eg) determined from Tauc plot was found in the range (3.44 to 4.18 eV) values.
- Full Text:
- Date Issued: 2017
Sedimentary, geochemical and geophysical study of the Ecca group, Karoo supergroup and its hydrocarbon potential in the Eastern Cape Province, South Africa
- Authors: Baiyegunhi, Christopher
- Date: 2017
- Subjects: Sediments (Geology) -- South Africa -- Eastern Cape Sedimentology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/4881 , vital:28658
- Description: The Ecca Group of Karoo Supergroup is a sedimentary rock sequence that deposited between the Late Carboniferous (Dwyka Group) and the Late Permian-Middle Triassic (Beaufort Group). The Ecca Group investigated in this study is situated in the Eastern Cape Province of South Africa and it comprises mainly of shales, mudstones, siltstones and sandstones. The Ecca Group sequence contains considerable carbon content and suitable thickness to make it an ideal target for shale gas exploration. Previous studies put more emphasis on the geology and stratigraphy of the Ecca Group, this study revised the stratigraphy, and put new insight on the petrography, depositional processes, sedimentary facies, provenance, paleoweathering, tectonic setting, subsidence rates and history, electrical resistivity, source rock characteristics and diagenesis of the potentially feasible sandstone and mudrock reservoir rocks of the Ecca Group. Based on the lithological features, sedimentary structures and facies characteristics, the stratigraphy of the Prince Albert, Whitehill, Collingham and Fort Brown Formations of the Ecca Group is now subdivided into two informal members each, i.e. Lower Member and Upper Member. Furthermore, the Ripon Formation is now subdivided into three informal members. Each member has been asigned a lithological name. The grain size parameters show that most of the Ecca Group sandstones are very fine to fine grained, poorly to moderately well sorted, mostly near-symmetrical and mesokurtic in grain-size distribution. The linear discriminant function analysis is dominantly indicative of turbidity current deposits under deep marine environment for Prince Albert, Whitehill and Collingham Formations, shallow marine environment for Ripon Formation, while the Fort Brown Formation is lacustrine-deltaic deposits. Modal composition analysis and petrography studies revealed that the detrital components of the sandstones are dominated by monocrystalline quartz, feldspar and lithic fragments. The sandstones are compositionally and texturally immature and can be classified as feldspathic wacke and lithic wacke. The provenance analysis revealed plutonic and metamorphic terrains as the main source rocks with minor debris derived from recycled sedimentary rocks. The detrital modal compositions of these sandstones are related to back arc to island and continental margin of tectonic setting. Based on the detailed sedimentological analyses of outcrop and borehole data, fourteen lithofacies were identified and seven facies associations (FAs) were recognised. The facies associations are: FA 1: Shale and mudstones intercalated with siltstones, FA 2: Carbonaceous shale, mudstone with subordinate chert and sandstone, FA 3: Mudstones rhythmite with thin bedded mudstone and lenticular siltstone, FA 4: Greyish medium bedded sandstone intercalated with laminated mudstone, FA 5: Dark-grey medium to thick bedded mudstone and siltstone, FA 6: Thin to medium bedded sandstone alternated with thin bedded carbonaceous mudstone, and FA 7: Varved mudstone rhythmite intercalated with siltstone and minor sandstone. Sedimentological characteristics of the identified facies associations indicate four deposition environments, namely, deep marine basin, turbidite, shallow marine and lacustrine environments, which constitute a gradually regression sequence as a result of sea-level dropping and shallowing of the basin during the developmental processes. Geochemical analysis of the Ecca mudrocks and sandstones revealed that the rocks are of quartzose sedimentary provenance, suggesting that they were derived from a cratonic interior or recycled orogen. The petrography and geochemistry of the sandstones indicated that the source areas are composed of plutonic and metamorphic rocks with a minor component from sedimentary rocks. The geochemical diagrams and indices of weathering suggested that the granitic source rocks underwent moderate to high degree of chemical weathering. The tectonic setting discrimination diagrams support passive continental margin setting of the provenance.
- Full Text:
- Date Issued: 2017
- Authors: Baiyegunhi, Christopher
- Date: 2017
- Subjects: Sediments (Geology) -- South Africa -- Eastern Cape Sedimentology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/4881 , vital:28658
- Description: The Ecca Group of Karoo Supergroup is a sedimentary rock sequence that deposited between the Late Carboniferous (Dwyka Group) and the Late Permian-Middle Triassic (Beaufort Group). The Ecca Group investigated in this study is situated in the Eastern Cape Province of South Africa and it comprises mainly of shales, mudstones, siltstones and sandstones. The Ecca Group sequence contains considerable carbon content and suitable thickness to make it an ideal target for shale gas exploration. Previous studies put more emphasis on the geology and stratigraphy of the Ecca Group, this study revised the stratigraphy, and put new insight on the petrography, depositional processes, sedimentary facies, provenance, paleoweathering, tectonic setting, subsidence rates and history, electrical resistivity, source rock characteristics and diagenesis of the potentially feasible sandstone and mudrock reservoir rocks of the Ecca Group. Based on the lithological features, sedimentary structures and facies characteristics, the stratigraphy of the Prince Albert, Whitehill, Collingham and Fort Brown Formations of the Ecca Group is now subdivided into two informal members each, i.e. Lower Member and Upper Member. Furthermore, the Ripon Formation is now subdivided into three informal members. Each member has been asigned a lithological name. The grain size parameters show that most of the Ecca Group sandstones are very fine to fine grained, poorly to moderately well sorted, mostly near-symmetrical and mesokurtic in grain-size distribution. The linear discriminant function analysis is dominantly indicative of turbidity current deposits under deep marine environment for Prince Albert, Whitehill and Collingham Formations, shallow marine environment for Ripon Formation, while the Fort Brown Formation is lacustrine-deltaic deposits. Modal composition analysis and petrography studies revealed that the detrital components of the sandstones are dominated by monocrystalline quartz, feldspar and lithic fragments. The sandstones are compositionally and texturally immature and can be classified as feldspathic wacke and lithic wacke. The provenance analysis revealed plutonic and metamorphic terrains as the main source rocks with minor debris derived from recycled sedimentary rocks. The detrital modal compositions of these sandstones are related to back arc to island and continental margin of tectonic setting. Based on the detailed sedimentological analyses of outcrop and borehole data, fourteen lithofacies were identified and seven facies associations (FAs) were recognised. The facies associations are: FA 1: Shale and mudstones intercalated with siltstones, FA 2: Carbonaceous shale, mudstone with subordinate chert and sandstone, FA 3: Mudstones rhythmite with thin bedded mudstone and lenticular siltstone, FA 4: Greyish medium bedded sandstone intercalated with laminated mudstone, FA 5: Dark-grey medium to thick bedded mudstone and siltstone, FA 6: Thin to medium bedded sandstone alternated with thin bedded carbonaceous mudstone, and FA 7: Varved mudstone rhythmite intercalated with siltstone and minor sandstone. Sedimentological characteristics of the identified facies associations indicate four deposition environments, namely, deep marine basin, turbidite, shallow marine and lacustrine environments, which constitute a gradually regression sequence as a result of sea-level dropping and shallowing of the basin during the developmental processes. Geochemical analysis of the Ecca mudrocks and sandstones revealed that the rocks are of quartzose sedimentary provenance, suggesting that they were derived from a cratonic interior or recycled orogen. The petrography and geochemistry of the sandstones indicated that the source areas are composed of plutonic and metamorphic rocks with a minor component from sedimentary rocks. The geochemical diagrams and indices of weathering suggested that the granitic source rocks underwent moderate to high degree of chemical weathering. The tectonic setting discrimination diagrams support passive continental margin setting of the provenance.
- Full Text:
- Date Issued: 2017
Self-determined development practices for a marginalised San community of Tsumkwe East in Otjozondjupa Region, Namibia
- Authors: Chingwe, Shuvai
- Date: 2017
- Subjects: San (African people) -- Namibia San (African people) -- Namibia -- Social conditions , San (African people) -- Namibia -- Politics and government Indigenous peoples -- Namibia
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/33239 , vital:32597
- Description: This study was an exploration of self-determined development practices as a panacea for poverty reduction in the San communities. The main aim of this study was to propose possible strategies for eliminating the marginalisation of San in order to reduce poverty. This study was guided by an Indigenous research paradigm. This study used an Indigenous research methodology because it ensures that research on Indigenous issues is carried out in a more respectful, ethical, correct, sympathetic, useful and beneficial fashion seen from the point of Indigenous people. Nine out of thirty-six villages in Tsumkwe East participated in this study. Data collection was done through key informant interviews and conversational methods namely talking circles and storying. The findings of this study reveal that the marginalisation of the Ju/’hoansi San of Nyae Nyae and other San communities is closely related to their loss of ancestral land during the colonial and post-colonial era. Although the Ju/’hoansi San have fought to maintain their ancestral lands, hunting which is their main livelihood has been restricted by government regulation. The restriction on their hunting and gathering culture has been the major contribution to their marginalisation as they can no longer fend for themselves as their forefathers used to do. Despite a multitude of factors militating against the self-determination of San communities, the Ju/’hoansi San have managed to express their voice through a remnant of their hunting and gathering culture. This study also reveals that there are two important actors in Nyae Nyae namely the government of the Republic of Namibia and the Nyae Nyae Conservancy. Nyae Nyae Conservancy is a community based natural resource management organisation which has taken a participatory developmental approach to the development of Tsumkwe East. The government has taken more of a welfare approach. Although the mainstream has labelled San people lazy, uneducated, backward and uncivilised, the success of the Nyae Nyae Conservancy which is managed by the Ju/’hoansi San is a testimony to the contrary. This study reveals that the government has failed to deliver on its policy of meeting all the welfare needs of the Ju/’hoansi San but the conservancy has risen to be a relevant organisation meeting the needs of the community whilst respecting their culture and identity as a hunting and gathering community. This study concludes that self-determined development practices maybe a panacea for the development of San communities. This can be made possible by supporting the San’s hunting and gathering livelihoods, respecting their culture, securing their land and resource rights, through long-term and consistent capacity building and supporting a culturally relevant education system.
- Full Text:
- Date Issued: 2017
- Authors: Chingwe, Shuvai
- Date: 2017
- Subjects: San (African people) -- Namibia San (African people) -- Namibia -- Social conditions , San (African people) -- Namibia -- Politics and government Indigenous peoples -- Namibia
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/33239 , vital:32597
- Description: This study was an exploration of self-determined development practices as a panacea for poverty reduction in the San communities. The main aim of this study was to propose possible strategies for eliminating the marginalisation of San in order to reduce poverty. This study was guided by an Indigenous research paradigm. This study used an Indigenous research methodology because it ensures that research on Indigenous issues is carried out in a more respectful, ethical, correct, sympathetic, useful and beneficial fashion seen from the point of Indigenous people. Nine out of thirty-six villages in Tsumkwe East participated in this study. Data collection was done through key informant interviews and conversational methods namely talking circles and storying. The findings of this study reveal that the marginalisation of the Ju/’hoansi San of Nyae Nyae and other San communities is closely related to their loss of ancestral land during the colonial and post-colonial era. Although the Ju/’hoansi San have fought to maintain their ancestral lands, hunting which is their main livelihood has been restricted by government regulation. The restriction on their hunting and gathering culture has been the major contribution to their marginalisation as they can no longer fend for themselves as their forefathers used to do. Despite a multitude of factors militating against the self-determination of San communities, the Ju/’hoansi San have managed to express their voice through a remnant of their hunting and gathering culture. This study also reveals that there are two important actors in Nyae Nyae namely the government of the Republic of Namibia and the Nyae Nyae Conservancy. Nyae Nyae Conservancy is a community based natural resource management organisation which has taken a participatory developmental approach to the development of Tsumkwe East. The government has taken more of a welfare approach. Although the mainstream has labelled San people lazy, uneducated, backward and uncivilised, the success of the Nyae Nyae Conservancy which is managed by the Ju/’hoansi San is a testimony to the contrary. This study reveals that the government has failed to deliver on its policy of meeting all the welfare needs of the Ju/’hoansi San but the conservancy has risen to be a relevant organisation meeting the needs of the community whilst respecting their culture and identity as a hunting and gathering community. This study concludes that self-determined development practices maybe a panacea for the development of San communities. This can be made possible by supporting the San’s hunting and gathering livelihoods, respecting their culture, securing their land and resource rights, through long-term and consistent capacity building and supporting a culturally relevant education system.
- Full Text:
- Date Issued: 2017
Sign language in South Africa: pedagogic approaches, policy developments and new directions
- Authors: Ganiso, Mirriam Nosiphiwo
- Date: 2017
- Subjects: Deaf -- Education -- South Africa , South African sign language -- Study and teaching , Sign language -- Study and teaching -- South Africa , Sign language -- Grammar
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/7323 , vital:21242
- Description: This objective of this thesis is to present and critique sign language-in-education policy and different teaching pedagogies used by teachers in the Eastern and Western Cape Deaf schools. The research was conducted in four Deaf schools in the Eastern and Western Cape Provinces. Data was collected through methods which include interviews, observations and questionnaires. The study results revealed that there was inconsistency of teaching approaches used by teachers in these different schools because some of them lacked knowledge and sign language skills. Additionally, many teachers who are teaching in Deaf schools did not get sign language training. Thus, the study concluded that some teachers lack knowledge of teaching methods. Also Deaf schools’ principals and school governing bodies employ teachers who are coming from the mainstream and who are not necessarily aware of Deaf children’s needs, forgetting that Deaf learners will struggle without suitable resources. Furthermore, the study concluded that teachers use different teaching approaches, such as Total Communication, Oral Approach, Signed English, Bilingualism, South African Sign Language (SASL) and other means of communication. Deaf learners were also forced to use Oral Communication although some of them were totally deaf. The research showed that Deaf learners and Deaf teacher assistants were not pleased about the way Deaf learners were being taught. Deaf learners complained about teachers, that they lack sign language communication skills and as a result the learners became the interpreters for the teachers. Teachers in turn complained about the curriculum training which was provided for individual and selected teachers. The research also offers a comparative study, in the sense that the development of sign language across different countries from Europe and Africa as well as the United States of America, is included. The thesis furthermore explores the development of SASL CAPS Curriculum in the Western Cape Province, i.e. grade R-3 which began in 2014 as opposed to the Eastern Cape teachers who experienced difficulties due to limited curriculum implementation resources. Therefore, this research suggests that, the Language Task Team which worked on the new CAPS curriculum should have involved Deaf teachers and teachers more generally in their team and decisions. The research sought to find a theoretical or grammatical basis for the development of SASL, while at the same time providing empirical data gathered from the four respective school sites. This data is analysed and presented in the thesis.
- Full Text:
- Date Issued: 2017
- Authors: Ganiso, Mirriam Nosiphiwo
- Date: 2017
- Subjects: Deaf -- Education -- South Africa , South African sign language -- Study and teaching , Sign language -- Study and teaching -- South Africa , Sign language -- Grammar
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/7323 , vital:21242
- Description: This objective of this thesis is to present and critique sign language-in-education policy and different teaching pedagogies used by teachers in the Eastern and Western Cape Deaf schools. The research was conducted in four Deaf schools in the Eastern and Western Cape Provinces. Data was collected through methods which include interviews, observations and questionnaires. The study results revealed that there was inconsistency of teaching approaches used by teachers in these different schools because some of them lacked knowledge and sign language skills. Additionally, many teachers who are teaching in Deaf schools did not get sign language training. Thus, the study concluded that some teachers lack knowledge of teaching methods. Also Deaf schools’ principals and school governing bodies employ teachers who are coming from the mainstream and who are not necessarily aware of Deaf children’s needs, forgetting that Deaf learners will struggle without suitable resources. Furthermore, the study concluded that teachers use different teaching approaches, such as Total Communication, Oral Approach, Signed English, Bilingualism, South African Sign Language (SASL) and other means of communication. Deaf learners were also forced to use Oral Communication although some of them were totally deaf. The research showed that Deaf learners and Deaf teacher assistants were not pleased about the way Deaf learners were being taught. Deaf learners complained about teachers, that they lack sign language communication skills and as a result the learners became the interpreters for the teachers. Teachers in turn complained about the curriculum training which was provided for individual and selected teachers. The research also offers a comparative study, in the sense that the development of sign language across different countries from Europe and Africa as well as the United States of America, is included. The thesis furthermore explores the development of SASL CAPS Curriculum in the Western Cape Province, i.e. grade R-3 which began in 2014 as opposed to the Eastern Cape teachers who experienced difficulties due to limited curriculum implementation resources. Therefore, this research suggests that, the Language Task Team which worked on the new CAPS curriculum should have involved Deaf teachers and teachers more generally in their team and decisions. The research sought to find a theoretical or grammatical basis for the development of SASL, while at the same time providing empirical data gathered from the four respective school sites. This data is analysed and presented in the thesis.
- Full Text:
- Date Issued: 2017
South African public sector property management: a performance model
- Mali-Swelindawo, Bongiwe Lorreta, Yan, Bingwen
- Authors: Mali-Swelindawo, Bongiwe Lorreta , Yan, Bingwen
- Date: 2017
- Subjects: Performance -- Management -- South Africa Performance standards -- South Africa , Public buildings -- South Africa Real estate management -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/21185 , vital:29454
- Description: This research was conducted with the intention of accomplishing effective property management (PM) in order for public sector properties in South Africa (SA) SA to fulfil more remarkably, public sector property stakeholders’ requirements. In particular, this study was concluded within a South African municipal environment with the specific purpose of alleviating South African municipalities from problems associated with overall poor operational performance, dissatisfied public sector property stakeholders, and inadequacies in competitiveness and global alignment. The primary objective of this study was to develop a performance model deemed necessary for the effective management of public sector properties in SA. This was achieved by developing a performance model for effective management of public sector properties, a model to systematically monitor, measure and control current expectations and changes within a public sector property management function. Herewith, performance model for effective management of public sector properties in South Africa. At the time of conducting this study, there was no conceptual model developed for performance management of public sector properties. In order to develop the performance model, the conceptual model identified key elements that included: 1) obsolescence and strategic factors; 2) global alignment; 3) finance and cost control; 4) PESTEL impact; 5) transformation and sustainability; 6) leadership and governance; and 7) monitoring, measurement and control as influences that directly impact a perceived successful management of public sector properties in SA. The study also took the form of a quantitative research project that included a formal survey of the identified population sample. The main statistical procedure employed was Structural Equation Modelling (SEM). Originally, the study offered 24 hypotheses; however, only 11 hypotheses could be confirmed by SEM measurement. Therefore, through SEM, the significance of the relationships between variables could be tested. Appropriate quantitative data were collected from public and private South African Built Environment professionals, students and other academics. The research made use of snowball sampling through questionnaires, with a sample size of 171. It is anticipated that findings of this study will be acknowledged by public sector PM in an effort to resolve PM problems through the incorporation of pertinent recommendations. Likewise, since the performance model for effective management of public sector properties was not extant prior to this study, this research is cutting-edge and therefore pioneering to PM, especially within the public sector.
- Full Text:
- Date Issued: 2017
- Authors: Mali-Swelindawo, Bongiwe Lorreta , Yan, Bingwen
- Date: 2017
- Subjects: Performance -- Management -- South Africa Performance standards -- South Africa , Public buildings -- South Africa Real estate management -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/21185 , vital:29454
- Description: This research was conducted with the intention of accomplishing effective property management (PM) in order for public sector properties in South Africa (SA) SA to fulfil more remarkably, public sector property stakeholders’ requirements. In particular, this study was concluded within a South African municipal environment with the specific purpose of alleviating South African municipalities from problems associated with overall poor operational performance, dissatisfied public sector property stakeholders, and inadequacies in competitiveness and global alignment. The primary objective of this study was to develop a performance model deemed necessary for the effective management of public sector properties in SA. This was achieved by developing a performance model for effective management of public sector properties, a model to systematically monitor, measure and control current expectations and changes within a public sector property management function. Herewith, performance model for effective management of public sector properties in South Africa. At the time of conducting this study, there was no conceptual model developed for performance management of public sector properties. In order to develop the performance model, the conceptual model identified key elements that included: 1) obsolescence and strategic factors; 2) global alignment; 3) finance and cost control; 4) PESTEL impact; 5) transformation and sustainability; 6) leadership and governance; and 7) monitoring, measurement and control as influences that directly impact a perceived successful management of public sector properties in SA. The study also took the form of a quantitative research project that included a formal survey of the identified population sample. The main statistical procedure employed was Structural Equation Modelling (SEM). Originally, the study offered 24 hypotheses; however, only 11 hypotheses could be confirmed by SEM measurement. Therefore, through SEM, the significance of the relationships between variables could be tested. Appropriate quantitative data were collected from public and private South African Built Environment professionals, students and other academics. The research made use of snowball sampling through questionnaires, with a sample size of 171. It is anticipated that findings of this study will be acknowledged by public sector PM in an effort to resolve PM problems through the incorporation of pertinent recommendations. Likewise, since the performance model for effective management of public sector properties was not extant prior to this study, this research is cutting-edge and therefore pioneering to PM, especially within the public sector.
- Full Text:
- Date Issued: 2017
Spatial and seasonal distribution of selected persistent organic pollutants and phenolic derivatives along the course of the Buffalo River in the Eastern Cape Province of South Africa
- Authors: Yahaya, Abdulrazaq
- Date: 2017
- Subjects: Organic water pollutants Water -- Purification -- Organic compounds removal
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/5939 , vital:29448
- Description:
Persistent organic pollutants (POPs) fall under a group of synthetic chemicals known for their persistence in environmental matrices such as soil and water, and are used in industrial, domestic and agricultural applications. Because of their volatility and lipophilicity, POPs can be transported far away from their point sources and bio-accumulate in food and in fatty tissues of humans and animals. In view of their toxicity and carcinogenicity some organic pollutants such as polychlorinated biphenyl (PCBs), organochlorine pesticides (OCPs) and phenolic derivatives (chlorophenol and nitrophenol) have been classified by United State Environmental Protection Agency (USEPA) and World Health Organization (WHO) as priority pollutants. The present work evaluated the distribution patterns of 19 polychlorinated biphenyls congeners, 17 organochlorine pesticides and selected phenolic derivatives (USEPA 11-priority pollutants) in the Buffalo River, in the Eastern Cape Province, South Africa between December 2015 and May 2016. The Liquid-liquid extraction technique was used for PCBs, OCPs and phenolic derivatives in the river water samples. Silica gel and florisil clean up were carried out for PCBs and OCPs samples respectively and analyzed with gas chromatography electron capture detector (GC/ECD). Phenolic compounds were derivatized and analyzed by gas chromatography mass spectrometer (GC/MS). Limits of detection (LOD), limit of quantitation (LOQ) and relative standard deviation (RSD) for the PCBs were 10 to 330 ng/L, 20 to 1,060 ng/L and 1.18 to 14.1 percent respectively. The LOD, LOQ and RSD for the OCPs were from 20 - 60 ng/L, 110 - 530 ng/L and 0.02 - 0.06 percent, while the corresponding values for the phenolic derivatives were 10 to 70 ng/L, 33 to 222 ng/L and 1.99 - 10.86 percent. In summer, the concentrations of PCBs, OCPs and phenolic derivatives ranged from
- Full Text:
- Date Issued: 2017
- Authors: Yahaya, Abdulrazaq
- Date: 2017
- Subjects: Organic water pollutants Water -- Purification -- Organic compounds removal
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/5939 , vital:29448
- Description:
Persistent organic pollutants (POPs) fall under a group of synthetic chemicals known for their persistence in environmental matrices such as soil and water, and are used in industrial, domestic and agricultural applications. Because of their volatility and lipophilicity, POPs can be transported far away from their point sources and bio-accumulate in food and in fatty tissues of humans and animals. In view of their toxicity and carcinogenicity some organic pollutants such as polychlorinated biphenyl (PCBs), organochlorine pesticides (OCPs) and phenolic derivatives (chlorophenol and nitrophenol) have been classified by United State Environmental Protection Agency (USEPA) and World Health Organization (WHO) as priority pollutants. The present work evaluated the distribution patterns of 19 polychlorinated biphenyls congeners, 17 organochlorine pesticides and selected phenolic derivatives (USEPA 11-priority pollutants) in the Buffalo River, in the Eastern Cape Province, South Africa between December 2015 and May 2016. The Liquid-liquid extraction technique was used for PCBs, OCPs and phenolic derivatives in the river water samples. Silica gel and florisil clean up were carried out for PCBs and OCPs samples respectively and analyzed with gas chromatography electron capture detector (GC/ECD). Phenolic compounds were derivatized and analyzed by gas chromatography mass spectrometer (GC/MS). Limits of detection (LOD), limit of quantitation (LOQ) and relative standard deviation (RSD) for the PCBs were 10 to 330 ng/L, 20 to 1,060 ng/L and 1.18 to 14.1 percent respectively. The LOD, LOQ and RSD for the OCPs were from 20 - 60 ng/L, 110 - 530 ng/L and 0.02 - 0.06 percent, while the corresponding values for the phenolic derivatives were 10 to 70 ng/L, 33 to 222 ng/L and 1.99 - 10.86 percent. In summer, the concentrations of PCBs, OCPs and phenolic derivatives ranged from
- Full Text:
- Date Issued: 2017
Statistical analysis and modelling of malaria relapse risk factors using Cox Proportional Hazards model approach : a case study of material data collected from Democratic Republic of Congo
- Authors: Mutambayi, Ruffin Mpiana
- Date: 2017
- Subjects: Malaria -- Congo (Democratic Republic) -- Mathematical models Statistics -- Congo (Democratic Republic) -- Econometric models
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15001 , vital:40110
- Description: The field of survival analysis has experienced tremendous growth during the latter half of the 20th century. The objective of this study was to model the relapsing time of uncomplicated falciparum malaria using biographical, sanitation, environmental and preventive information as covariate risk factors. The methodological developments of survival analysis that have had the most profound impact are the Kaplan-Meier method for estimating the survival function, the log-rank test for comparing the equality of two or more survival distributions, and the Cox proportional hazards (PH) model for examining the covariate effects on the hazard function. This thesis presents basic concepts, nonparametric methods (the Kaplan-Meier method and the log-rank test), semi parametric methods (the Cox PH model, and Cox model with time-dependent covariates) and parametric methods (Parametric PH model and the AFT model) for analysing survival data. An improved method was applied to randomized uncomplicated falciparum malaria patients to investigate the risk factors related to the relapsing time in RD Congo. Firstly, the Cox PH model , inf 1 0 ( ) ( )exp 1.91613 0.49633 0.81466 dump spr t X h h t X X X where is the instantaneous risk of experiencing the event at time , without the influence of any covariate was found to better fit the data, as confirmed by the results of the global test that present reasonable and significant results: (Likelihood Ratio: 18.2264 with p-value < 0.0004; Score: 17.6569 with p-value < 0.0005 and Wald: 19.3975 with p<0.0002). Hence from the model above, it can be noticed that ‘dumping site’ (p-value <0.0106; 95percent HR C.I: 1.545, 29.451), ‘spray used’ (p-value < 0. 0.0220; 95percent C.I: 0.391, 0.915), and ‘information related to source of malaria’ (p-value < 0. 0.0012; 95percent C.I: 1.380, 3.725), have a significant impact on the relapsing time of the patients under investigation. It should be noted that many 0() h tt other important covariates such as “usage of mosquito nets” were excluded because of the non-proportionality of the hazards. Secondly, the improvement concept was applied to the Cox model as proposed, and the improved model was as follows: h h t t X t X t X t X t X t X t X t r dump_inf1 spr_inf1 Where h0 (t) is the instantaneous risk of experiencing the event at time t , without the influence of any covariate. The model was found to better fit the data than the standard model — as confirmed by the results from the convergence criterion comparison, where the AIC value of the improved model (754.460) was lower than that of the standard model (767.428). Moreover, the improved model was found to be adequate as the results from the global null hypothesis were significant: (Likelihood Ratio: p-value is 0.0001; Score: p-value is 0.0001; Wald: p-value is 0.0001) and the goodness-of-fit test was confirmed by the plotting of Coxresiduals where the 45 degrees’ line confirmed the results. In conclusion, it was found that the covariates ‘pit’ (p-value is 0.0009; 95percent HR C.I: 11.4133, 1.243e+04), ‘tdwel_spr’ (pvalue = 0.0257; 95percent HR C.I: 1.0016, 1.030e+00), ‘tdwel_inf1 (p-value = 0.0122; 95percent HR C.I: 0.9691, 9.964e-01), ‘maint_dump’ (p-value is 0.0005; 95percent HR C.I: 1.0239, 1.087e+00),‘maint_pit’ (p-value is 0.0007; 95percent HR C.I: 0.9179, 9.774e-01), ‘dump_spr’ (p-value is 0.0027; 95percent HR C.I: 0.9308, 9.853e-01), ‘dump_inf1’ (p-value <0.0001; 95percent HR C.I: 0.9849, 9.947e-01) and ‘spr_inf1’ (p-value is 0.0005; 95percent HR C.I: 1.0119, 1.043e+00) affected the time to relapse from uncomplicated falciparum malaria.
- Full Text:
- Date Issued: 2017
- Authors: Mutambayi, Ruffin Mpiana
- Date: 2017
- Subjects: Malaria -- Congo (Democratic Republic) -- Mathematical models Statistics -- Congo (Democratic Republic) -- Econometric models
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15001 , vital:40110
- Description: The field of survival analysis has experienced tremendous growth during the latter half of the 20th century. The objective of this study was to model the relapsing time of uncomplicated falciparum malaria using biographical, sanitation, environmental and preventive information as covariate risk factors. The methodological developments of survival analysis that have had the most profound impact are the Kaplan-Meier method for estimating the survival function, the log-rank test for comparing the equality of two or more survival distributions, and the Cox proportional hazards (PH) model for examining the covariate effects on the hazard function. This thesis presents basic concepts, nonparametric methods (the Kaplan-Meier method and the log-rank test), semi parametric methods (the Cox PH model, and Cox model with time-dependent covariates) and parametric methods (Parametric PH model and the AFT model) for analysing survival data. An improved method was applied to randomized uncomplicated falciparum malaria patients to investigate the risk factors related to the relapsing time in RD Congo. Firstly, the Cox PH model , inf 1 0 ( ) ( )exp 1.91613 0.49633 0.81466 dump spr t X h h t X X X where is the instantaneous risk of experiencing the event at time , without the influence of any covariate was found to better fit the data, as confirmed by the results of the global test that present reasonable and significant results: (Likelihood Ratio: 18.2264 with p-value < 0.0004; Score: 17.6569 with p-value < 0.0005 and Wald: 19.3975 with p<0.0002). Hence from the model above, it can be noticed that ‘dumping site’ (p-value <0.0106; 95percent HR C.I: 1.545, 29.451), ‘spray used’ (p-value < 0. 0.0220; 95percent C.I: 0.391, 0.915), and ‘information related to source of malaria’ (p-value < 0. 0.0012; 95percent C.I: 1.380, 3.725), have a significant impact on the relapsing time of the patients under investigation. It should be noted that many 0() h tt other important covariates such as “usage of mosquito nets” were excluded because of the non-proportionality of the hazards. Secondly, the improvement concept was applied to the Cox model as proposed, and the improved model was as follows: h h t t X t X t X t X t X t X t X t r dump_inf1 spr_inf1 Where h0 (t) is the instantaneous risk of experiencing the event at time t , without the influence of any covariate. The model was found to better fit the data than the standard model — as confirmed by the results from the convergence criterion comparison, where the AIC value of the improved model (754.460) was lower than that of the standard model (767.428). Moreover, the improved model was found to be adequate as the results from the global null hypothesis were significant: (Likelihood Ratio: p-value is 0.0001; Score: p-value is 0.0001; Wald: p-value is 0.0001) and the goodness-of-fit test was confirmed by the plotting of Coxresiduals where the 45 degrees’ line confirmed the results. In conclusion, it was found that the covariates ‘pit’ (p-value is 0.0009; 95percent HR C.I: 11.4133, 1.243e+04), ‘tdwel_spr’ (pvalue = 0.0257; 95percent HR C.I: 1.0016, 1.030e+00), ‘tdwel_inf1 (p-value = 0.0122; 95percent HR C.I: 0.9691, 9.964e-01), ‘maint_dump’ (p-value is 0.0005; 95percent HR C.I: 1.0239, 1.087e+00),‘maint_pit’ (p-value is 0.0007; 95percent HR C.I: 0.9179, 9.774e-01), ‘dump_spr’ (p-value is 0.0027; 95percent HR C.I: 0.9308, 9.853e-01), ‘dump_inf1’ (p-value <0.0001; 95percent HR C.I: 0.9849, 9.947e-01) and ‘spr_inf1’ (p-value is 0.0005; 95percent HR C.I: 1.0119, 1.043e+00) affected the time to relapse from uncomplicated falciparum malaria.
- Full Text:
- Date Issued: 2017
Statistical viability assessment of a photovoltaic system in the presence of data uncertainty
- Authors: Clohessy, Chantelle May
- Date: 2017
- Subjects: Bayesian field theory , Photovoltaic power systems
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/15655 , vital:28280
- Description: This thesis investigates statistical techniques that can be used to improve estimates and methods in feasibility assessments of photovoltaic (PV) systems. The use of these techniques are illustrated for a case study of a 1MW PV system proposed for the Nelson Mandela Metropolitan University South Campus in Port Elizabeth, South Africa. The results from the study provide strong support for the use of multivariate profile analysis and interval estimate plots for the assessment of solar resource data. A unique view to manufacturing process control in the generation of energy from a PV system is identified. This link between PV energy generation and process control is lacking in the literature and exploited in this study. Variance component models are used to model power output and energy yield estimates of the proposed PV system. The variance components are simulated using Bayesian simulation techniques. Bayesian tolerance intervals are derived from the variance components and are used to determine what percentage of future power output and energy yield values fall within an interval with a certain probability. The results from the estimated tolerance intervals were informative and provided expected power outputs and energy yields for a given month and specific season. The methods improve on current techniques used to assess the energy output of a system.
- Full Text:
- Date Issued: 2017
- Authors: Clohessy, Chantelle May
- Date: 2017
- Subjects: Bayesian field theory , Photovoltaic power systems
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/15655 , vital:28280
- Description: This thesis investigates statistical techniques that can be used to improve estimates and methods in feasibility assessments of photovoltaic (PV) systems. The use of these techniques are illustrated for a case study of a 1MW PV system proposed for the Nelson Mandela Metropolitan University South Campus in Port Elizabeth, South Africa. The results from the study provide strong support for the use of multivariate profile analysis and interval estimate plots for the assessment of solar resource data. A unique view to manufacturing process control in the generation of energy from a PV system is identified. This link between PV energy generation and process control is lacking in the literature and exploited in this study. Variance component models are used to model power output and energy yield estimates of the proposed PV system. The variance components are simulated using Bayesian simulation techniques. Bayesian tolerance intervals are derived from the variance components and are used to determine what percentage of future power output and energy yield values fall within an interval with a certain probability. The results from the estimated tolerance intervals were informative and provided expected power outputs and energy yields for a given month and specific season. The methods improve on current techniques used to assess the energy output of a system.
- Full Text:
- Date Issued: 2017
Strategies to prepare and support the role transition of significant others in becoming caregivers of persons with dementia
- Authors: Smith, Lourett
- Date: 2017
- Subjects: Dementia -- Patients -- Care -- South Africa Caregivers -- Mental health -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/20856 , vital:29407
- Description: Significant others of persons with dementia face many challenges when caring for their loved ones in the home. I became aware of the challenges that significant others of persons with dementia face when caring for persons with dementia, when I was working as a registered nurse in a psychiatric hospital. As a junior registered nurse I found it challenging at times to manage persons with dementia due to the behavioural problems that they exhibited. It occurred to me at the time that significant others who became caregivers of persons with dementia must struggle with their role as caregivers, not having the necessary knowledge and skills to care for them. Literature confirms my observation that significant others need assistance when they experience the transition from being a significant other to being a caregiver of a person with dementia. Significant others often have to deal with many additional role transitions once they become caregivers. Such role transitions could include having to cope with empty nest syndrome and retirement among others, as well as having to deal with caring for their relative. They are prone to stress, burnout and other problems related to caring. By preparing significant others for their main role transition into becoming a caregiver and providing them with support, many of these problems could be prevented and the person with dementia would benefit as a result. Literature also highlights that there is a paucity of research dealing with the role transition of significant others who become the caregivers of persons with dementia. Therefore, the aim of the study was to provide an understanding of how significant others experience providing care to persons with dementia. The study also aimed to understand how significant others were prepared and supported in their role as caregivers as they went through their role transition. The study also aimed to develop strategies to enable psychiatric nurses (APNs), psychiatric nurses (PNs) and other healthcare professionals to prepare and support significant others during their role transition into caregivers of persons with dementia. The study followed a qualitative approach with an exploratory, contextual, descriptive design, applying the Middle-Range Transition Theory as the paradigm and phenomenology as the meta-paradigm. Visual narrative inquiry was utilised using collages and semi-structured individual interviews to collect the data from participants who were the caregivers of persons with dementia. They were purposefully selected from a non-profit Alzheimer’s clinic in the Nelson Mandela Bay Municipality (NMBM). A sample size of eight participants was included. A conceptual framework was used for the development of the strategies for APNs/ PNs and other healthcare professionals to prepare and support significant others during their role transition from significant others to caregivers of persons with dementia. The principles of professional research ethics were adhered to throughout the study.
- Full Text:
- Date Issued: 2017
- Authors: Smith, Lourett
- Date: 2017
- Subjects: Dementia -- Patients -- Care -- South Africa Caregivers -- Mental health -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/20856 , vital:29407
- Description: Significant others of persons with dementia face many challenges when caring for their loved ones in the home. I became aware of the challenges that significant others of persons with dementia face when caring for persons with dementia, when I was working as a registered nurse in a psychiatric hospital. As a junior registered nurse I found it challenging at times to manage persons with dementia due to the behavioural problems that they exhibited. It occurred to me at the time that significant others who became caregivers of persons with dementia must struggle with their role as caregivers, not having the necessary knowledge and skills to care for them. Literature confirms my observation that significant others need assistance when they experience the transition from being a significant other to being a caregiver of a person with dementia. Significant others often have to deal with many additional role transitions once they become caregivers. Such role transitions could include having to cope with empty nest syndrome and retirement among others, as well as having to deal with caring for their relative. They are prone to stress, burnout and other problems related to caring. By preparing significant others for their main role transition into becoming a caregiver and providing them with support, many of these problems could be prevented and the person with dementia would benefit as a result. Literature also highlights that there is a paucity of research dealing with the role transition of significant others who become the caregivers of persons with dementia. Therefore, the aim of the study was to provide an understanding of how significant others experience providing care to persons with dementia. The study also aimed to understand how significant others were prepared and supported in their role as caregivers as they went through their role transition. The study also aimed to develop strategies to enable psychiatric nurses (APNs), psychiatric nurses (PNs) and other healthcare professionals to prepare and support significant others during their role transition into caregivers of persons with dementia. The study followed a qualitative approach with an exploratory, contextual, descriptive design, applying the Middle-Range Transition Theory as the paradigm and phenomenology as the meta-paradigm. Visual narrative inquiry was utilised using collages and semi-structured individual interviews to collect the data from participants who were the caregivers of persons with dementia. They were purposefully selected from a non-profit Alzheimer’s clinic in the Nelson Mandela Bay Municipality (NMBM). A sample size of eight participants was included. A conceptual framework was used for the development of the strategies for APNs/ PNs and other healthcare professionals to prepare and support significant others during their role transition from significant others to caregivers of persons with dementia. The principles of professional research ethics were adhered to throughout the study.
- Full Text:
- Date Issued: 2017
Strategies used to cater for students with diverse academic backgrounds in the provision of textile, clothing and design programmes: a case study of two universities of technology in Zimbabwe
- Authors: Chimbindi, Felisia
- Date: 2017
- Subjects: Multicultural education -- Zimbabwe -- Cross-cultural studies Inclusive education -- Zimbabwe -- Cross-cultural studies
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/4948 , vital:28871
- Description: Universities admit students from diverse backgrounds and have an obligation to accommodate all the students in various educational programmes to ensure that they acquire relevant skills and knowledge. The provision of Textile, Clothing and Design programmes to students with diverse academic backgrounds in universities of technology in Zimbabwe has led to various concerns raised by the textile and clothing stakeholders. The concerns include poor performance of students, high student failure rate, high student drop out, late completion of programmes by students, and other problems emanating from curriculum implementation approaches used by the lecturers. This study therefore, sought to find out how students with diverse academic backgrounds are catered for in the provision of TCD programmes in the two sampled universities of technology in Zimbabwe, with a view to assist the students and to enhance the quality of TCD provision. The study adopted a post-positivism paradigm and used a mixed method research approach that integrated concurrent qualitative and quantitative procedures in data collection, analysis and interpretation. A questionnaire, interviews and document analysis were used to collect data from respondents. Purposive sampling procedure was used to select 36 TCD lecturers, 2 universities’ quality assurance directors, 2 TCD faculty deans of studies, and 2 department chairpersons. Collected data were analyzed using statistical and non-statistical procedures. The study revealed that catering for students with diverse academic backgrounds was practiced in the two universities despite the absence of a curriculum implementation policy to guide the provision of TCD programmes to students with diverse academic backgrounds at university level. It emerged that catering for students with diverse academic backgrounds in implementing TCD curricular at the two sampled universities was faced with various challenges that include lack of lecturer training with regard to catering for students from diverse academic backgrounds and inadequate lecturer training in depth TCD subject content knowledge and ICT teaching technology packages. The study also revealed that there is not enough university and stakeholder participation with regards to supporting and monitoring curriculum implementation process to cater for students with diverse academic backgrounds. Although there were challenges encountered in catering for students with diverse academic backgrounds, the study reveals that there are pockets of good practice in some curriculum implementation strategies implemented by the two institutions such as use of student centered teaching and instructional approaches, university support and lecturer commitment to assist the students. The study findings conclude that although catering for TCD students with diverse academic backgrounds was being practiced in the two universities of technology, there are very critical issues observed over the programmes implementation process that include absence of curriculum implementation policy, lack of training of lecturers and inadequate participative TCD stakeholder involvement. Based on the study findings and reviewed literature, the researcher suggests an alternative curriculum implementation framework for catering for students with diverse academic backgrounds that may help improve effectiveness of university programmes implementation.
- Full Text:
- Date Issued: 2017
- Authors: Chimbindi, Felisia
- Date: 2017
- Subjects: Multicultural education -- Zimbabwe -- Cross-cultural studies Inclusive education -- Zimbabwe -- Cross-cultural studies
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/4948 , vital:28871
- Description: Universities admit students from diverse backgrounds and have an obligation to accommodate all the students in various educational programmes to ensure that they acquire relevant skills and knowledge. The provision of Textile, Clothing and Design programmes to students with diverse academic backgrounds in universities of technology in Zimbabwe has led to various concerns raised by the textile and clothing stakeholders. The concerns include poor performance of students, high student failure rate, high student drop out, late completion of programmes by students, and other problems emanating from curriculum implementation approaches used by the lecturers. This study therefore, sought to find out how students with diverse academic backgrounds are catered for in the provision of TCD programmes in the two sampled universities of technology in Zimbabwe, with a view to assist the students and to enhance the quality of TCD provision. The study adopted a post-positivism paradigm and used a mixed method research approach that integrated concurrent qualitative and quantitative procedures in data collection, analysis and interpretation. A questionnaire, interviews and document analysis were used to collect data from respondents. Purposive sampling procedure was used to select 36 TCD lecturers, 2 universities’ quality assurance directors, 2 TCD faculty deans of studies, and 2 department chairpersons. Collected data were analyzed using statistical and non-statistical procedures. The study revealed that catering for students with diverse academic backgrounds was practiced in the two universities despite the absence of a curriculum implementation policy to guide the provision of TCD programmes to students with diverse academic backgrounds at university level. It emerged that catering for students with diverse academic backgrounds in implementing TCD curricular at the two sampled universities was faced with various challenges that include lack of lecturer training with regard to catering for students from diverse academic backgrounds and inadequate lecturer training in depth TCD subject content knowledge and ICT teaching technology packages. The study also revealed that there is not enough university and stakeholder participation with regards to supporting and monitoring curriculum implementation process to cater for students with diverse academic backgrounds. Although there were challenges encountered in catering for students with diverse academic backgrounds, the study reveals that there are pockets of good practice in some curriculum implementation strategies implemented by the two institutions such as use of student centered teaching and instructional approaches, university support and lecturer commitment to assist the students. The study findings conclude that although catering for TCD students with diverse academic backgrounds was being practiced in the two universities of technology, there are very critical issues observed over the programmes implementation process that include absence of curriculum implementation policy, lack of training of lecturers and inadequate participative TCD stakeholder involvement. Based on the study findings and reviewed literature, the researcher suggests an alternative curriculum implementation framework for catering for students with diverse academic backgrounds that may help improve effectiveness of university programmes implementation.
- Full Text:
- Date Issued: 2017
Studies on acoustic properties of non-woven fabrics
- Authors: Mvubu, Mlando Basel
- Date: 2017
- Subjects: Needlepunch (Nonwoven fabric) Nonwoven fabrics , Textile fabrics
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/19387 , vital:28866
- Description: This study is divided in to two main parts. The first part deals with the optimization of process parameters of needle-punched non-woven fabrics for achieving maximum sound absorption by employing a Box-Behnken factorial design. The influence of fibre type, depth of needle penetration and stroke frequency on sound absorption properties were studied. These parameters were varied at three levels during experimental trials. From multiple regression analysis, it was observed that the depth of needle penetration alone was the most dominant factor among the selected parameters, which was followed by the interaction between depth of needle penetration and stroke frequency. Fibre type was the least dominant parameter affecting sound absorption. A maximum sound absorption coefficient of 47% (0.47) was obtained from the selected parameters. The results showed that for a process such as needle-punching, which is influenced by multiple variables, it is important to also study the interactive effects of process parameters for achieving optimum sound absorption. The second part of the study deals with the effect of type of natural fibre (fineness), and the blending ratio (with PET fibres) on the air permeability of the needle-punched non-woven fabrics and then it proceeds to study the effect of the air-gap, type of natural fibre (fineness) and blending ratio (with PET fibres) on sound absorption of needle-punched non-woven fabrics. These parameters are tested individually and their two way interaction (synergy) effect using ANOVA. The air-gap was varied from 0mm to 25mm with 5mm increments, three natural fibre types were used and all were blended with polyester fibres at three blending ratios for each natural fibre type. The Univariate Tests of Significance shows that all three parameters have a significant effect on sound absorption together with two two-way interactions, with the exception of the Blend Ratio × Air Gap two-way interaction which was not significant. It was found that the sound absorption improves with the increase in the air-gap size up to 15mm after which sound absorption decreased slightly with the further increase in the air-gap up to 25mm.
- Full Text:
- Date Issued: 2017
- Authors: Mvubu, Mlando Basel
- Date: 2017
- Subjects: Needlepunch (Nonwoven fabric) Nonwoven fabrics , Textile fabrics
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/19387 , vital:28866
- Description: This study is divided in to two main parts. The first part deals with the optimization of process parameters of needle-punched non-woven fabrics for achieving maximum sound absorption by employing a Box-Behnken factorial design. The influence of fibre type, depth of needle penetration and stroke frequency on sound absorption properties were studied. These parameters were varied at three levels during experimental trials. From multiple regression analysis, it was observed that the depth of needle penetration alone was the most dominant factor among the selected parameters, which was followed by the interaction between depth of needle penetration and stroke frequency. Fibre type was the least dominant parameter affecting sound absorption. A maximum sound absorption coefficient of 47% (0.47) was obtained from the selected parameters. The results showed that for a process such as needle-punching, which is influenced by multiple variables, it is important to also study the interactive effects of process parameters for achieving optimum sound absorption. The second part of the study deals with the effect of type of natural fibre (fineness), and the blending ratio (with PET fibres) on the air permeability of the needle-punched non-woven fabrics and then it proceeds to study the effect of the air-gap, type of natural fibre (fineness) and blending ratio (with PET fibres) on sound absorption of needle-punched non-woven fabrics. These parameters are tested individually and their two way interaction (synergy) effect using ANOVA. The air-gap was varied from 0mm to 25mm with 5mm increments, three natural fibre types were used and all were blended with polyester fibres at three blending ratios for each natural fibre type. The Univariate Tests of Significance shows that all three parameters have a significant effect on sound absorption together with two two-way interactions, with the exception of the Blend Ratio × Air Gap two-way interaction which was not significant. It was found that the sound absorption improves with the increase in the air-gap size up to 15mm after which sound absorption decreased slightly with the further increase in the air-gap up to 25mm.
- Full Text:
- Date Issued: 2017
Synthesis and biological evaluation of anti-HIV-I integrase agents
- Jesumoroti, Omobolanle Janet
- Authors: Jesumoroti, Omobolanle Janet
- Date: 2017
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/59215 , vital:27479
- Description: Expected release date-April 2019
- Full Text:
- Date Issued: 2017
- Authors: Jesumoroti, Omobolanle Janet
- Date: 2017
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/59215 , vital:27479
- Description: Expected release date-April 2019
- Full Text:
- Date Issued: 2017
Synthesis and investigation of the chemosensing properties of novel fluorescent triazolyl coumarin-based polymers
- Ngororabanga, Jean Marie Vianney
- Authors: Ngororabanga, Jean Marie Vianney
- Date: 2017
- Subjects: Fluorescent polymers Chemical detectors
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/20110 , vital:29120
- Description: Environmental pollution by ionic species has become one of the greatest challenges to the sustainable development of communities. Increasing amounts of these ionic species in the environment is associated with several detrimental effects to human health and ecological systems. Proper detection and monitoring of these ionic species is essential. Considering the diversity of the ions and the fact that the available sensors are limited, it is clear that there is need for a rapid and low-cost method for recognition and monitoring of these ions. Fluorescence based methods are ranked among the most powerful transduction systems to signal chemical recognition events. Fluorescent polymers containing triazolyl coumarin units in the polymer backbone or as pendant groups were therefore designed and investigated as potential sensors for these ions. Three methods were used to incorporate triazolyl coumarin units into the polymers. The first method involved polymerization of the vinyl monomer containing the triazolyl coumarin unit. The second method involved AA-BB step-grow click polymerization of diazide and dialkyne-functionalized monomers. The third method involved post-polymerization functionalization of an azide-functionalized polymer with an alkyne functionalized coumarin derivative. In each method, formation of the triazole ring was achieved using a Cu(I)-catalyzed 1,3-dipolar cycloaddition (CuAAC) reaction. The photophysical properties of the polymers and their starting monomers were investigated and compared. Polymers with triazolyl coumarin units in the backbone or as pendant groups were found to have higher absorption and emission intensities than their corresponding monomers while polymers resulting from functionalization of azide-functionalized polymer were found to exhibit improved photophysical properties compared to the starting azide-functionalized polymer. The chemosensing potential of the polymers was investigated through absorption and emission. The polymers were found to be selective towards different metal ions (Fe3+, Hg2+ and Al3+) and anions (-OH and F-). The mechanisms of interaction between the polymers and ions were investigated by comparing the absorption and emission spectra of the polymers to those of their monomers in the presence of an ion of interest. In some cases the mechanism of interaction was supported by 1H NMR and FT-IR.
- Full Text:
- Date Issued: 2017
- Authors: Ngororabanga, Jean Marie Vianney
- Date: 2017
- Subjects: Fluorescent polymers Chemical detectors
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/20110 , vital:29120
- Description: Environmental pollution by ionic species has become one of the greatest challenges to the sustainable development of communities. Increasing amounts of these ionic species in the environment is associated with several detrimental effects to human health and ecological systems. Proper detection and monitoring of these ionic species is essential. Considering the diversity of the ions and the fact that the available sensors are limited, it is clear that there is need for a rapid and low-cost method for recognition and monitoring of these ions. Fluorescence based methods are ranked among the most powerful transduction systems to signal chemical recognition events. Fluorescent polymers containing triazolyl coumarin units in the polymer backbone or as pendant groups were therefore designed and investigated as potential sensors for these ions. Three methods were used to incorporate triazolyl coumarin units into the polymers. The first method involved polymerization of the vinyl monomer containing the triazolyl coumarin unit. The second method involved AA-BB step-grow click polymerization of diazide and dialkyne-functionalized monomers. The third method involved post-polymerization functionalization of an azide-functionalized polymer with an alkyne functionalized coumarin derivative. In each method, formation of the triazole ring was achieved using a Cu(I)-catalyzed 1,3-dipolar cycloaddition (CuAAC) reaction. The photophysical properties of the polymers and their starting monomers were investigated and compared. Polymers with triazolyl coumarin units in the backbone or as pendant groups were found to have higher absorption and emission intensities than their corresponding monomers while polymers resulting from functionalization of azide-functionalized polymer were found to exhibit improved photophysical properties compared to the starting azide-functionalized polymer. The chemosensing potential of the polymers was investigated through absorption and emission. The polymers were found to be selective towards different metal ions (Fe3+, Hg2+ and Al3+) and anions (-OH and F-). The mechanisms of interaction between the polymers and ions were investigated by comparing the absorption and emission spectra of the polymers to those of their monomers in the presence of an ion of interest. In some cases the mechanism of interaction was supported by 1H NMR and FT-IR.
- Full Text:
- Date Issued: 2017
Synthesis of indium and lead phthalocyanine as photocatalysts for photodynamic antimicrobial chemotherapy and photo-oxidation of pollutants
- Authors: Oluwole, Oluyinka David
- Date: 2017
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/5293 , vital:20805
- Full Text:
- Date Issued: 2017
- Authors: Oluwole, Oluyinka David
- Date: 2017
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/5293 , vital:20805
- Full Text:
- Date Issued: 2017
Synthesis of indium and lead phthalocyanine as photocatalysts for photodynamic antimicrobial chemotherapy and photo-oxidation of pollutants
- Authors: Osifeko, Olawale L
- Date: 2017
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/5221 , vital:20790
- Description: This thesis explores the synthesis of metallophthalocyanines as potential photosensitizers for application in photodynamic antimicrobial chemotherapy and phototransformation of environmental pollutants. The metallophthalocyanines containing amino substituent were conjugated with magnetic nanoparticle and semiconductor quantum dots via an amide bond and by chemisorption onto gold nanoparticles surface. Techniques such as time-resolved fluorescence measurements, transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), elemental analysis, fourier transform infrared (FTIR), nuclear magnetic resonance (¹H, ¹³C, and cozy of symmetrical phthalocyanine), electronic spectroscopy, as well as mass spectroscopy were employed to characterize all metallophthalocyanines. Quarternized pyridyloxy substituted phthalocyanine and asymmetric (AB3) metallophthalocyanines were embedded in electrospun polystyrene fiber. General trends are described for quantum yields of fluorescence, triplet, singlet oxygen and photodegradation as well as lifetimes of fluorescence and triplet state of the compounds. There is an increase in triplet quantum yield for Pcs in the presence of gold nanoparticles (AuNPs) and semiconductor quantum dots (QDs), but not in the presence of magnetic nanoparticles (MNPs). Photodynamic inactivation of Escherichia coli with the quarternized photosensitizers at low concentrations totally inactivate the bacteria compared to non-charged photosensitiser. Also, a similar trend was observed for the magnetic nanoparticles conjugates. Photooxidations of bisphenol A and 4-chlorophenol were carried out in this study using two asymmetric Indium(III) phthalocyanines photosensitizers. The photooxidation reactions were compared with those of a symmetrical indium(III) phthalocyanines containing four quaternized 4-pyridyloxy substituents. The complexes were embedded in electrospun polystyrene fiber for heterogeneous photocatalysis. The immobilized photosensitizers possess good singlet oxygen generation potentials in aqueous media. The asymmetrical phthalocyanine containing 4-pyridylsulfanyl and one aminophenoxy showed the best photocatalytic behavior.
- Full Text:
- Date Issued: 2017
- Authors: Osifeko, Olawale L
- Date: 2017
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/5221 , vital:20790
- Description: This thesis explores the synthesis of metallophthalocyanines as potential photosensitizers for application in photodynamic antimicrobial chemotherapy and phototransformation of environmental pollutants. The metallophthalocyanines containing amino substituent were conjugated with magnetic nanoparticle and semiconductor quantum dots via an amide bond and by chemisorption onto gold nanoparticles surface. Techniques such as time-resolved fluorescence measurements, transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), elemental analysis, fourier transform infrared (FTIR), nuclear magnetic resonance (¹H, ¹³C, and cozy of symmetrical phthalocyanine), electronic spectroscopy, as well as mass spectroscopy were employed to characterize all metallophthalocyanines. Quarternized pyridyloxy substituted phthalocyanine and asymmetric (AB3) metallophthalocyanines were embedded in electrospun polystyrene fiber. General trends are described for quantum yields of fluorescence, triplet, singlet oxygen and photodegradation as well as lifetimes of fluorescence and triplet state of the compounds. There is an increase in triplet quantum yield for Pcs in the presence of gold nanoparticles (AuNPs) and semiconductor quantum dots (QDs), but not in the presence of magnetic nanoparticles (MNPs). Photodynamic inactivation of Escherichia coli with the quarternized photosensitizers at low concentrations totally inactivate the bacteria compared to non-charged photosensitiser. Also, a similar trend was observed for the magnetic nanoparticles conjugates. Photooxidations of bisphenol A and 4-chlorophenol were carried out in this study using two asymmetric Indium(III) phthalocyanines photosensitizers. The photooxidation reactions were compared with those of a symmetrical indium(III) phthalocyanines containing four quaternized 4-pyridyloxy substituents. The complexes were embedded in electrospun polystyrene fiber for heterogeneous photocatalysis. The immobilized photosensitizers possess good singlet oxygen generation potentials in aqueous media. The asymmetrical phthalocyanine containing 4-pyridylsulfanyl and one aminophenoxy showed the best photocatalytic behavior.
- Full Text:
- Date Issued: 2017
Systematics and biogeography of forest snails, chondrocyclus (mollusca: gastropoda: caenogastropoda: cyclophoridae) in Southern Africa
- Authors: Cole, Mary Louise
- Date: 2017
- Subjects: Chondrocyclus , Mollusks -- South Africa , Cyclophoridae -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/4356 , vital:20651
- Description: This study presents a molecular phylogeny and systematic revision of Chondrocyclus, the major South African group of the large family of operculate terrestrial molluscs, the Cyclophoridae. Chondrocyclus snails are small gastropods found in forest and moist thicket throughout South Africa. This is the first detailed systematic treatment of a group of Cyclophoridae in mainland Africa and the first to provide molecular data. This study complements regional studies on the systematics of the family in Asia and provides comparative data for studies of higher level relationships within the Cyclophoridae. Phylogenetic reconstruction by BI and ML methods of combined and single gene datasets of 16S and CO 1 all showed Chondrocyclus to be monophyletic and recovered five well-supported clades that corresponded to groups of populations identifiable on the basis of combinations of morphological characters. Species were diagnosed morphologically and were shown to be genetically distinct lineages. Informative morphological features include shell dimensions, protoconch, periostracum, operculum, radula and penis. Two species in Afromontane regions of Zimbabwe and Malawi respectively are excluded from Chondrocyclus based on morphology and tentatively placed in Cyathopoma. Diversity recognised within the genus more than doubled, from a previous seven South African species to seventeen. Re-descriptions of established species and descriptions of new species are provided, together with photographs of morphological characteristics. New taxon names and nomenclatural acts within it are disclaimed and are therefore not available in the sense of the International Code of Zoological Nomenclature until validly published elsewhere. Several cryptic species within previously widespread “species” and unrecorded narrowly endemic species were documented. The clade consisting of populations of “Chondrocyclus isipingoensis”, now considered to be a species complex, was sister to a group containing the other four clades. The “Isipingoensis” clade occurs widely in Afromontane regions, along the Great Escarpment, and on the south-east coast. The other four clades occur from Zululand to the Cape Peninsula with a pattern of east-west lineage turnover. The biogeography of Chondrocyclus is interpreted by comparison with concordant patterns in other terrestrial molluscs and unrelated taxa with poor dispersal ability. This study complements other research on composition, spatial distribution and phylogenetic diversity of low-vagility invertebrates and expands the data available for biodiversity conservation in South Africa.
- Full Text:
- Date Issued: 2017
- Authors: Cole, Mary Louise
- Date: 2017
- Subjects: Chondrocyclus , Mollusks -- South Africa , Cyclophoridae -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/4356 , vital:20651
- Description: This study presents a molecular phylogeny and systematic revision of Chondrocyclus, the major South African group of the large family of operculate terrestrial molluscs, the Cyclophoridae. Chondrocyclus snails are small gastropods found in forest and moist thicket throughout South Africa. This is the first detailed systematic treatment of a group of Cyclophoridae in mainland Africa and the first to provide molecular data. This study complements regional studies on the systematics of the family in Asia and provides comparative data for studies of higher level relationships within the Cyclophoridae. Phylogenetic reconstruction by BI and ML methods of combined and single gene datasets of 16S and CO 1 all showed Chondrocyclus to be monophyletic and recovered five well-supported clades that corresponded to groups of populations identifiable on the basis of combinations of morphological characters. Species were diagnosed morphologically and were shown to be genetically distinct lineages. Informative morphological features include shell dimensions, protoconch, periostracum, operculum, radula and penis. Two species in Afromontane regions of Zimbabwe and Malawi respectively are excluded from Chondrocyclus based on morphology and tentatively placed in Cyathopoma. Diversity recognised within the genus more than doubled, from a previous seven South African species to seventeen. Re-descriptions of established species and descriptions of new species are provided, together with photographs of morphological characteristics. New taxon names and nomenclatural acts within it are disclaimed and are therefore not available in the sense of the International Code of Zoological Nomenclature until validly published elsewhere. Several cryptic species within previously widespread “species” and unrecorded narrowly endemic species were documented. The clade consisting of populations of “Chondrocyclus isipingoensis”, now considered to be a species complex, was sister to a group containing the other four clades. The “Isipingoensis” clade occurs widely in Afromontane regions, along the Great Escarpment, and on the south-east coast. The other four clades occur from Zululand to the Cape Peninsula with a pattern of east-west lineage turnover. The biogeography of Chondrocyclus is interpreted by comparison with concordant patterns in other terrestrial molluscs and unrelated taxa with poor dispersal ability. This study complements other research on composition, spatial distribution and phylogenetic diversity of low-vagility invertebrates and expands the data available for biodiversity conservation in South Africa.
- Full Text:
- Date Issued: 2017
Talent management: a case study of Namibia’s Directorate of Civil Aviation (DCA) in securing talent for aviation safety, 2008 to 2014
- Authors: Simataa, George
- Date: 2017
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/7131 , vital:21220
- Description: This study is about talent management, focusing on a case study of the initiatives undertaken by the Directorate of Civil Aviation (DCA) of Namibia over the period 2008 to 2014 in securing talent for aviation safety. The International Civil Aviation Organisation (ICAO) regularly assesses the extent to which member states comply with their safety oversight responsibilities. According to a 1996 report by the ICAO, under the auspices of its Universal Safety Oversight and Security Audit Programme (USOSAP), Namibia’s safety oversight was found to be weak, as indicative of the State’s inability to guarantee the safety of aircraft operations within the national airspace (ICAO, 1996). One of the significant audit findings was the critical shortage of qualified professionals at the Directorate Civil Aviation (DCA) to effectively perform the State’s regulatory and oversight function as contained in the Chicago Convention of 1944. The shortage of qualified professionals resulted in Namibia being unable to respond to its obligations and responsibilities under the Chicago Convention and Namibia’s subsequent blacklisting by the ICAO Audit Result Review Board (ARRB). Consequently, a corrective action plan was undertaken. This study examines one aspect of this plan, namely the initiatives that were undertaken to secure the talent required for aviation safety posts. The aim of the research is, from the perspective of talent management, to analyse the corrective action plan of the Directorate of Civil Aviation (DCA), as a process of securing talent for strategic positions in aviation safety in Namibia. This initiative was analysed from the perspective of the fourth stream of talent management, which emphasises securing talent for strategic positions (Collings and Mellahi, 2009; Huselid & Becker, 2011). Taking into account the fact that Namibia was a racially and culturally divided society until about 25 years ago, the study also deals with issues of diversity management as they impacted upon the talent management of the civil aviation industry nationally. Furthermore, the study is located against the background of the Bantu Education System that was provided by the apartheid South African government to Namibians before independence in 1990. The research design of this study involved conducting a case study that followed a deductive approach. Data were collected using multiple methods and sources such as documentation, interviews and archival records. Content analysis was used in the analysis of collected data. The findings of the study showed the talent management strategies that were adopted in managing strategic positions, the challenges encountered and the impact of the programme. The findings were initially discussed from the perspective of stream four of talent management, with its focus on strategic positions in organisations. Some of the findings of the study were in line with this approach to talent management, but certain challenges that were encountered in carrying out the talent management programme could not be addressed from this perspective, thereby exposing the limits of this approach to talent management in an emerging economy like Namibia. Consequently, a proposed model of sustainable talent management for the DCA was developed. From the perspective of this model of sustainable talent management, recommendations were made for practice and further research.
- Full Text:
- Date Issued: 2017
- Authors: Simataa, George
- Date: 2017
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/7131 , vital:21220
- Description: This study is about talent management, focusing on a case study of the initiatives undertaken by the Directorate of Civil Aviation (DCA) of Namibia over the period 2008 to 2014 in securing talent for aviation safety. The International Civil Aviation Organisation (ICAO) regularly assesses the extent to which member states comply with their safety oversight responsibilities. According to a 1996 report by the ICAO, under the auspices of its Universal Safety Oversight and Security Audit Programme (USOSAP), Namibia’s safety oversight was found to be weak, as indicative of the State’s inability to guarantee the safety of aircraft operations within the national airspace (ICAO, 1996). One of the significant audit findings was the critical shortage of qualified professionals at the Directorate Civil Aviation (DCA) to effectively perform the State’s regulatory and oversight function as contained in the Chicago Convention of 1944. The shortage of qualified professionals resulted in Namibia being unable to respond to its obligations and responsibilities under the Chicago Convention and Namibia’s subsequent blacklisting by the ICAO Audit Result Review Board (ARRB). Consequently, a corrective action plan was undertaken. This study examines one aspect of this plan, namely the initiatives that were undertaken to secure the talent required for aviation safety posts. The aim of the research is, from the perspective of talent management, to analyse the corrective action plan of the Directorate of Civil Aviation (DCA), as a process of securing talent for strategic positions in aviation safety in Namibia. This initiative was analysed from the perspective of the fourth stream of talent management, which emphasises securing talent for strategic positions (Collings and Mellahi, 2009; Huselid & Becker, 2011). Taking into account the fact that Namibia was a racially and culturally divided society until about 25 years ago, the study also deals with issues of diversity management as they impacted upon the talent management of the civil aviation industry nationally. Furthermore, the study is located against the background of the Bantu Education System that was provided by the apartheid South African government to Namibians before independence in 1990. The research design of this study involved conducting a case study that followed a deductive approach. Data were collected using multiple methods and sources such as documentation, interviews and archival records. Content analysis was used in the analysis of collected data. The findings of the study showed the talent management strategies that were adopted in managing strategic positions, the challenges encountered and the impact of the programme. The findings were initially discussed from the perspective of stream four of talent management, with its focus on strategic positions in organisations. Some of the findings of the study were in line with this approach to talent management, but certain challenges that were encountered in carrying out the talent management programme could not be addressed from this perspective, thereby exposing the limits of this approach to talent management in an emerging economy like Namibia. Consequently, a proposed model of sustainable talent management for the DCA was developed. From the perspective of this model of sustainable talent management, recommendations were made for practice and further research.
- Full Text:
- Date Issued: 2017
The 'failure-success' dichotomy in migration discourse and practice : revisiting reverse migration deterrents for South Africa based Zimbabwean skilled migrants
- Authors: Nzima, Divane
- Date: 2017
- Subjects: Return migration -- Zimbabwe Return migration -- South Africa Zimbabwe -- Emigration and immigration -- Economic aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/5434 , vital:29243
- Description: The study was conceptualised against the background that leading migration theories explain return migration based on failure and success alone. The neo-classical economics theory of migration perceives return migration as a by-product of a failed migration experience while the new economics of labour migration perceives return as occurring after successful achievement of migration objectives. This study questions these theoretical positions through an exploration of the factors that deter South Africa-based Zimbabwean skilled migrants from returning home permanently notwithstanding a successful or failed migration experience. Furtive economic factors in Zimbabwe and South Africa that dissuade skilled migrants from returning home permanently are explored. Social factors in Zimbabwe and in South Africa that influence return migration decision making are also examined. Furthermore, the study analysed whether and how Zimbabwean skilled migrants are forced into a permanent settlement in South Africa as a result of what this study calls the ‘diaspora trap’. This ‘diaspora trap’ framework argues that Zimbabwean skilled migrants in South Africa do not return following their experiences of failure and success in South Africa. Central to the absence of return is the social construction of migrants as successful in Zimbabwe. Skilled migrants are deterred from returning due to their failure to meet family and communal expectations of success. In addition, return migration is deferred as a means to hide poverty in South Africa. Moreover, new diaspora family ties weaken attachments with Zimbabwe and contribute to deferred return migration. Skilled migrants are thus entrapped in South Africa by their failure to live up to the success social construct and the inability to mitigate adversities in the host country.
- Full Text:
- Date Issued: 2017
- Authors: Nzima, Divane
- Date: 2017
- Subjects: Return migration -- Zimbabwe Return migration -- South Africa Zimbabwe -- Emigration and immigration -- Economic aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/5434 , vital:29243
- Description: The study was conceptualised against the background that leading migration theories explain return migration based on failure and success alone. The neo-classical economics theory of migration perceives return migration as a by-product of a failed migration experience while the new economics of labour migration perceives return as occurring after successful achievement of migration objectives. This study questions these theoretical positions through an exploration of the factors that deter South Africa-based Zimbabwean skilled migrants from returning home permanently notwithstanding a successful or failed migration experience. Furtive economic factors in Zimbabwe and South Africa that dissuade skilled migrants from returning home permanently are explored. Social factors in Zimbabwe and in South Africa that influence return migration decision making are also examined. Furthermore, the study analysed whether and how Zimbabwean skilled migrants are forced into a permanent settlement in South Africa as a result of what this study calls the ‘diaspora trap’. This ‘diaspora trap’ framework argues that Zimbabwean skilled migrants in South Africa do not return following their experiences of failure and success in South Africa. Central to the absence of return is the social construction of migrants as successful in Zimbabwe. Skilled migrants are deterred from returning due to their failure to meet family and communal expectations of success. In addition, return migration is deferred as a means to hide poverty in South Africa. Moreover, new diaspora family ties weaken attachments with Zimbabwe and contribute to deferred return migration. Skilled migrants are thus entrapped in South Africa by their failure to live up to the success social construct and the inability to mitigate adversities in the host country.
- Full Text:
- Date Issued: 2017
The adoption of employee share ownership plans (ESOPs) in Nigeria
- Authors: Akponah, Voke Blessing
- Date: 2017
- Subjects: Employee ownership -- Nigeria , Profit-sharing -- Nigeria Management -- Employee participation -- Nigeria Nigeria -- Economic aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/13834 , vital:27312
- Description: This study investigated the factors that influence the adoption of ESOPs in Nigeria. Furthermore, the study investigated the influence of the adoption of ESOPs on organisational performance, employee retention and employee commitment. The study results reveal that trade union responsiveness, reforms, awareness of employee benefits and taxation implication positively influence the adoption of ESOPs based on transparency. The results in this study further reveal that trade union responsiveness, takeovers, reforms, awareness of employee benefits and taxation implication effectively influence the adoption of ESOPs based on two-way communication. In addition, the study results reveal that trade union responsiveness, takeovers, reforms, awareness of employee benefits and trust positively influence the adoption of ESOPs based on empowerment. The study further reveals that adoption of ESOPs based on transparency, two-way communication and empowerment leads to organisational performance, employee retention and employee commitment. This study, being the first of its kind in Nigeria, filled the gap that existed in the Nigerian literature in respect of the awareness and adoption of ESOPs. This study provides literature and theoretical model that can be used as a foundation by organisations and the government to start up the adoption of ESOPs. This study showed that ESOPs is beneficial to boost the economy, enhance desired organisational outcomes (organisational performance, employee retention and employee commitment) and meet the financial and retirement needs of employees. However, for organisations and employees to enjoy the full benefits of ESOPs, underlying forces such as, trade union responsiveness, takeovers, reforms, awareness of employee benefits, trusts and taxation implication must be taken into account. Furthermore, the adoption, implementation and operations of ESOPs will be successful management, trade union leaders and employees utilise strategies such as, transparency, two-way communication and empowerment.
- Full Text:
- Date Issued: 2017
- Authors: Akponah, Voke Blessing
- Date: 2017
- Subjects: Employee ownership -- Nigeria , Profit-sharing -- Nigeria Management -- Employee participation -- Nigeria Nigeria -- Economic aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/13834 , vital:27312
- Description: This study investigated the factors that influence the adoption of ESOPs in Nigeria. Furthermore, the study investigated the influence of the adoption of ESOPs on organisational performance, employee retention and employee commitment. The study results reveal that trade union responsiveness, reforms, awareness of employee benefits and taxation implication positively influence the adoption of ESOPs based on transparency. The results in this study further reveal that trade union responsiveness, takeovers, reforms, awareness of employee benefits and taxation implication effectively influence the adoption of ESOPs based on two-way communication. In addition, the study results reveal that trade union responsiveness, takeovers, reforms, awareness of employee benefits and trust positively influence the adoption of ESOPs based on empowerment. The study further reveals that adoption of ESOPs based on transparency, two-way communication and empowerment leads to organisational performance, employee retention and employee commitment. This study, being the first of its kind in Nigeria, filled the gap that existed in the Nigerian literature in respect of the awareness and adoption of ESOPs. This study provides literature and theoretical model that can be used as a foundation by organisations and the government to start up the adoption of ESOPs. This study showed that ESOPs is beneficial to boost the economy, enhance desired organisational outcomes (organisational performance, employee retention and employee commitment) and meet the financial and retirement needs of employees. However, for organisations and employees to enjoy the full benefits of ESOPs, underlying forces such as, trade union responsiveness, takeovers, reforms, awareness of employee benefits, trusts and taxation implication must be taken into account. Furthermore, the adoption, implementation and operations of ESOPs will be successful management, trade union leaders and employees utilise strategies such as, transparency, two-way communication and empowerment.
- Full Text:
- Date Issued: 2017
The assembly of p-aryl triazole foldamers into double and other super- helical structures
- Okerio, Jaspher Mosomi, Klumperman, Bert
- Authors: Okerio, Jaspher Mosomi , Klumperman, Bert
- Date: 2017
- Subjects: Supramolecular chemistry Chemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/20548 , vital:29319
- Description: The assembly of poly(para-aryltriazoles) (pPATs), synthesized via Cu(I)-catalysed azide-alkyne cycloaddition, into highly ordered structures is investigated. Firstly, the assembly of the pPATs into double helical structures, as a function of solvent quality and side chain chirality, was studied. The solvents employed (DMF and water) induced changes in van der Waals forces and surface free energy thus influencing the order of the pPATs’ random coils into double helical structures. The observed double helical structures, assembly that was analyzed using ultraviolet-visible (UV-Vis) specroscopy, circular dichroism (CD) spectroscopy, scanning transmission electron microscopy (STEM) and confocal fluorescence imaging microscopy upon addition of 0 – 80% water into the pPATs’ random coils, exhibit stable morphologies stabilized by π-π stacking and hydrogen bonding at 80% water content. The pPATs exist as random coils at 10% water in DMF. At 40% water in DMF, the pPATs’ strands were observed to exist in a side-by-side orientation. The adjacent strands, side by side, intertwine into double helices and eventually stack as the amount of water is increased to 80%. The obtained results present a facile strategy for the fabrication of polymeric double helical structures with stable morphologies. The average diameter of the resulting one-handed and opposite handed double helical structures is about 200 nm, a pitch of 170 nm and an overall length of several micrometres. The assembly of the pPATs into ordered structures in the presence of a neutral organic template and anions was also assessed. Hydrophobic poly(γ-benzyl-L-glutamate) (PBLG) template was introduced at various concentrations and transition region of the pPATs (10% water in DMF). At this stage the PBLG template is CD inactive. The template modified the assembly mechanism to afford structures, which cannot be achieved in its absence. It disallows the organization of the pPATs into double helical structures. The pPATs strands thread around the template and stack into long tubules of up to 10 microns and irregular diameter. The irregular diameter is attributed to uneven threading of pPATs strands around the template at some sections. The sensitivity and binding ability of the pPAT system to halide ions such as F-, Cl- and Br- , which involves re-organization of the aryl-triazole bonds, is explored using NMR and UV-Vis and CD spectroscopies. Br- which induces the highest shift of the triazole C-H proton signal in the NMR analysis also shows the highest dynamic quenching of the pPATs’ UV-Vis and CD spectra. The UV-Vis and CD signals are linearly dependent on the concentration of the anions. This confirms non-aggregation assembly in the presence of anions. Conclusively, the pPATs interact with the bromide anion in aqueous solution, which consequently prevents the aggregation of the foldamers. Finally, using PATs with different amounts of chiral side chains, co-operativity among side chains that leads to transfer, propagation and amplification of chirality is confirmed. A non-linear dependence of the CD signal on the amount of chiral side chains was observed. Chiral amplification was observed as low as 1% of the chiral side chains. However, approximately 20% of the chiral side chains are needed to obtain half the intensity of the cotton effect exhibited by the homochiral pPAT.
- Full Text:
- Date Issued: 2017
- Authors: Okerio, Jaspher Mosomi , Klumperman, Bert
- Date: 2017
- Subjects: Supramolecular chemistry Chemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/20548 , vital:29319
- Description: The assembly of poly(para-aryltriazoles) (pPATs), synthesized via Cu(I)-catalysed azide-alkyne cycloaddition, into highly ordered structures is investigated. Firstly, the assembly of the pPATs into double helical structures, as a function of solvent quality and side chain chirality, was studied. The solvents employed (DMF and water) induced changes in van der Waals forces and surface free energy thus influencing the order of the pPATs’ random coils into double helical structures. The observed double helical structures, assembly that was analyzed using ultraviolet-visible (UV-Vis) specroscopy, circular dichroism (CD) spectroscopy, scanning transmission electron microscopy (STEM) and confocal fluorescence imaging microscopy upon addition of 0 – 80% water into the pPATs’ random coils, exhibit stable morphologies stabilized by π-π stacking and hydrogen bonding at 80% water content. The pPATs exist as random coils at 10% water in DMF. At 40% water in DMF, the pPATs’ strands were observed to exist in a side-by-side orientation. The adjacent strands, side by side, intertwine into double helices and eventually stack as the amount of water is increased to 80%. The obtained results present a facile strategy for the fabrication of polymeric double helical structures with stable morphologies. The average diameter of the resulting one-handed and opposite handed double helical structures is about 200 nm, a pitch of 170 nm and an overall length of several micrometres. The assembly of the pPATs into ordered structures in the presence of a neutral organic template and anions was also assessed. Hydrophobic poly(γ-benzyl-L-glutamate) (PBLG) template was introduced at various concentrations and transition region of the pPATs (10% water in DMF). At this stage the PBLG template is CD inactive. The template modified the assembly mechanism to afford structures, which cannot be achieved in its absence. It disallows the organization of the pPATs into double helical structures. The pPATs strands thread around the template and stack into long tubules of up to 10 microns and irregular diameter. The irregular diameter is attributed to uneven threading of pPATs strands around the template at some sections. The sensitivity and binding ability of the pPAT system to halide ions such as F-, Cl- and Br- , which involves re-organization of the aryl-triazole bonds, is explored using NMR and UV-Vis and CD spectroscopies. Br- which induces the highest shift of the triazole C-H proton signal in the NMR analysis also shows the highest dynamic quenching of the pPATs’ UV-Vis and CD spectra. The UV-Vis and CD signals are linearly dependent on the concentration of the anions. This confirms non-aggregation assembly in the presence of anions. Conclusively, the pPATs interact with the bromide anion in aqueous solution, which consequently prevents the aggregation of the foldamers. Finally, using PATs with different amounts of chiral side chains, co-operativity among side chains that leads to transfer, propagation and amplification of chirality is confirmed. A non-linear dependence of the CD signal on the amount of chiral side chains was observed. Chiral amplification was observed as low as 1% of the chiral side chains. However, approximately 20% of the chiral side chains are needed to obtain half the intensity of the cotton effect exhibited by the homochiral pPAT.
- Full Text:
- Date Issued: 2017