Electrospun fiber based colorimetric probes for aspartate aminotransferase and I7ß-estradiol
- Authors: Pule, Bellah Oreeditse
- Date: 2014
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54869 , vital:26623
- Description: Fabrication, characterization and application of electrospun polymer composite based colorimetric probes are presented in this thesis. The first part of the thesis involved the development of a protocol for in situ reduction of gold trication (Au³+) into metallic gold atoms with sodium borohydride. The prepared PS-Au NPs showed an SPR band at 542 nm. Furthermore the absorbance of the colloidal Au NPs in polystyrene exhibited a good linear correlation (r2 = 0.9934) to E2 concentration in the range 5 to 50 ppb. The lowest naked eye detection limit was found to be 0.5 ppb and could further be easily monitored by UV-vis spectrophotometer. Upon interaction with E2 Au NPs aggregated to give nanoparticle clusters, confirmed through TEM analysis. Different concentrations of Au NPs were found to have a significant effect on the conductivity of the PS-Au NPs solution. At low concentrations of Au NPs (0.002, 0.015 and 0.025% w/v) PS-Au NPs solution could be electrospun without clogging. The FE-SEM images showed a non-beaded morphology of PS-Au NPs composite fibers. Upon interaction of the colorimetric probe strips with various E2 concentrations it was observed that with increasing E2 concentrations (50 ng/ml to 1000 µg/ml) the colour of the probe changed gradually from white to shades of pink and eventually to shades of blue at higher E2 concentrations. The visible cut-off concentration was 100 ng/ml. The second component of the thesis focussed on the development of diazonium dye-nylon 6 colorimetric probe for aspartate aminotransferase. At optimal pH 7.4 the enzyme was stable, highly active and catalyzed a reaction that was susceptible to detailed kinetic analysis by continuous optical methods. The KM values for L-aspartate, a- ketoglutarate and oxaloacetate were 2.60, 0.59 and 0.066 mM, respectively. On the basis of these KM values the solid-state colorimetric probe was developed. A colour change occurred when an electrospun dye-N 6 probes were exposed to visibly detectable concentrations of oxaloacetate, an AST-catalyzed reaction product. While monitoring AST activity at 530 run, a linear relation was obtained between oxaloacetate concentrations ranging from 0.4 - 7.4 µg/ml. Naked eye detection limit of 2.4 µg/ml oxalaoacetate equivalence of 10 times the normal AST activity was attained. The colorimetric probe was in addition, tested against co-substrates aspartate, ketoglutarate and a variety of other compounds such as alanine, pryruvate, as well as glutamic, malaic and succinic acids known to interfere with AST activity. Each compound elicited a distinct and unambiguous colour change upon interaction with the colorimetric probe. Further X-ray powder diffraction (XRD), duNouy ring tensiometer, Brunauer- Emmett- Teller (BET) and energy dispersive X-ray spectroscopy (EDS/EDX) characterization confirmed composition and stability of the colorimetric probes. Colorimetric probes developed in this thesis are relatively cost effective, simple and "rugged" for measurement of analytes with visual detection without sample pretreatment in matrices, such as plasma and dairy effluents. The probes warrant further investigation as they have shown potential and offer a promising solid-state platform for both clinical diagnostics and environmental monitoring.
- Full Text:
- Date Issued: 2014
- Authors: Pule, Bellah Oreeditse
- Date: 2014
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54869 , vital:26623
- Description: Fabrication, characterization and application of electrospun polymer composite based colorimetric probes are presented in this thesis. The first part of the thesis involved the development of a protocol for in situ reduction of gold trication (Au³+) into metallic gold atoms with sodium borohydride. The prepared PS-Au NPs showed an SPR band at 542 nm. Furthermore the absorbance of the colloidal Au NPs in polystyrene exhibited a good linear correlation (r2 = 0.9934) to E2 concentration in the range 5 to 50 ppb. The lowest naked eye detection limit was found to be 0.5 ppb and could further be easily monitored by UV-vis spectrophotometer. Upon interaction with E2 Au NPs aggregated to give nanoparticle clusters, confirmed through TEM analysis. Different concentrations of Au NPs were found to have a significant effect on the conductivity of the PS-Au NPs solution. At low concentrations of Au NPs (0.002, 0.015 and 0.025% w/v) PS-Au NPs solution could be electrospun without clogging. The FE-SEM images showed a non-beaded morphology of PS-Au NPs composite fibers. Upon interaction of the colorimetric probe strips with various E2 concentrations it was observed that with increasing E2 concentrations (50 ng/ml to 1000 µg/ml) the colour of the probe changed gradually from white to shades of pink and eventually to shades of blue at higher E2 concentrations. The visible cut-off concentration was 100 ng/ml. The second component of the thesis focussed on the development of diazonium dye-nylon 6 colorimetric probe for aspartate aminotransferase. At optimal pH 7.4 the enzyme was stable, highly active and catalyzed a reaction that was susceptible to detailed kinetic analysis by continuous optical methods. The KM values for L-aspartate, a- ketoglutarate and oxaloacetate were 2.60, 0.59 and 0.066 mM, respectively. On the basis of these KM values the solid-state colorimetric probe was developed. A colour change occurred when an electrospun dye-N 6 probes were exposed to visibly detectable concentrations of oxaloacetate, an AST-catalyzed reaction product. While monitoring AST activity at 530 run, a linear relation was obtained between oxaloacetate concentrations ranging from 0.4 - 7.4 µg/ml. Naked eye detection limit of 2.4 µg/ml oxalaoacetate equivalence of 10 times the normal AST activity was attained. The colorimetric probe was in addition, tested against co-substrates aspartate, ketoglutarate and a variety of other compounds such as alanine, pryruvate, as well as glutamic, malaic and succinic acids known to interfere with AST activity. Each compound elicited a distinct and unambiguous colour change upon interaction with the colorimetric probe. Further X-ray powder diffraction (XRD), duNouy ring tensiometer, Brunauer- Emmett- Teller (BET) and energy dispersive X-ray spectroscopy (EDS/EDX) characterization confirmed composition and stability of the colorimetric probes. Colorimetric probes developed in this thesis are relatively cost effective, simple and "rugged" for measurement of analytes with visual detection without sample pretreatment in matrices, such as plasma and dairy effluents. The probes warrant further investigation as they have shown potential and offer a promising solid-state platform for both clinical diagnostics and environmental monitoring.
- Full Text:
- Date Issued: 2014
Electrospun fibre based colorimetric probes for biological molecules
- Authors: Mudabuka, Boitumelo
- Date: 2014
- Subjects: Nanofibers , Vitamin C , Dopamine
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4535 , http://hdl.handle.net/10962/d1016354
- Description: The thesis reports the use of electrospun nanofibres as a platform for the development of colorimetric probes. Three colorimetric probes in the form of electrospun nanofibre test strips were developed for the selective detection of ascorbic acid and dopamine because they are crucial biomolecules for physiological processes in human metabolism and usually coexist in biological samples. The simultaneous detection of the biomolecules is very important as their abnormal concentration levels would lead to diseases such as Parkinson's and schizophrenia. Different methods of incorporating detector agents into the nanofibre were exploited for the detection of the biomolecules. The methods included physical incorporation of nanoparticles, covalent bonding of ligand/dyes through surface modification of the fibres. The first colorimetric test strip for ascorbic acid was based on copper-gold alloy nanoparticles prepared in-situ and hosted in nylon6. The test strip showed selectivity in detecting ascorbic acid in the pH range 2 – 7. The suitability of fibres in hosting copper-gold alloy nanoparticles for the colorimetric detection of ascorbic acid was investigated using nylon6, poly(vinyl benzyl chloride)-styrene and cellulose acetate based test strips. All the test strips exhibited leaching and the nylon6 based test strip was found to be thermally stable up to 60 ˚C. The colorimetric performance of the test strips was maintained and neither was colour decay exhibited after 10 months of storage in a shelf. The test strip achieved an eye-ball limit of detection of 1.76 x10-2 mg L-1 and its suitability was demonstrated by the determination of ascorbic acid in fruit juices, urine, serum, and vitamin C tablets. The second colorimetric test strip for ascorbic acid and dopamine employed prussian blue synthesised in-situ in nylon6. Ascorbic acid turned the deep blue test strip to light blue at pH 3, and a faded navy blue colour at a pH range of 6 - 7 while dopamine changed the strip to purple at the same pH range. The versatility of the test strip was demonstrated by detecting ascorbic acid in commercial fruit juices as well as by detecting ascorbic acid as well as dopamine in fortified urine. The eye-ball detection limit of the Prussian blue test strip for ascorbic acid and dopamine was 17.6 mg L-1 and 18.9 mg L-1, respectively. The third method involved a covalent approach, where poly(vinylbenzyl chloride) nanofibers were post functionalised with 2-(2′-pyridyl)-imidazole and iron(III) for the selective detection of ascorbic acid and dopamine. The eye-ball detection limit for ascorbic acid and dopamine was 17.6 mg L-1 and 18.9 mg L-1, respectively. The test strip was selective for dopamine, but the detection of ascorbic acid suffered from interference by glutathione. The application of the test strips was nevertheless demonstrated by the detection of ascorbic acid in fruit juices and dopamine in fortified urine. The developed test strips employing the three approaches were applied without sample pre-treatment and use of supporting equipment.
- Full Text:
- Date Issued: 2014
- Authors: Mudabuka, Boitumelo
- Date: 2014
- Subjects: Nanofibers , Vitamin C , Dopamine
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4535 , http://hdl.handle.net/10962/d1016354
- Description: The thesis reports the use of electrospun nanofibres as a platform for the development of colorimetric probes. Three colorimetric probes in the form of electrospun nanofibre test strips were developed for the selective detection of ascorbic acid and dopamine because they are crucial biomolecules for physiological processes in human metabolism and usually coexist in biological samples. The simultaneous detection of the biomolecules is very important as their abnormal concentration levels would lead to diseases such as Parkinson's and schizophrenia. Different methods of incorporating detector agents into the nanofibre were exploited for the detection of the biomolecules. The methods included physical incorporation of nanoparticles, covalent bonding of ligand/dyes through surface modification of the fibres. The first colorimetric test strip for ascorbic acid was based on copper-gold alloy nanoparticles prepared in-situ and hosted in nylon6. The test strip showed selectivity in detecting ascorbic acid in the pH range 2 – 7. The suitability of fibres in hosting copper-gold alloy nanoparticles for the colorimetric detection of ascorbic acid was investigated using nylon6, poly(vinyl benzyl chloride)-styrene and cellulose acetate based test strips. All the test strips exhibited leaching and the nylon6 based test strip was found to be thermally stable up to 60 ˚C. The colorimetric performance of the test strips was maintained and neither was colour decay exhibited after 10 months of storage in a shelf. The test strip achieved an eye-ball limit of detection of 1.76 x10-2 mg L-1 and its suitability was demonstrated by the determination of ascorbic acid in fruit juices, urine, serum, and vitamin C tablets. The second colorimetric test strip for ascorbic acid and dopamine employed prussian blue synthesised in-situ in nylon6. Ascorbic acid turned the deep blue test strip to light blue at pH 3, and a faded navy blue colour at a pH range of 6 - 7 while dopamine changed the strip to purple at the same pH range. The versatility of the test strip was demonstrated by detecting ascorbic acid in commercial fruit juices as well as by detecting ascorbic acid as well as dopamine in fortified urine. The eye-ball detection limit of the Prussian blue test strip for ascorbic acid and dopamine was 17.6 mg L-1 and 18.9 mg L-1, respectively. The third method involved a covalent approach, where poly(vinylbenzyl chloride) nanofibers were post functionalised with 2-(2′-pyridyl)-imidazole and iron(III) for the selective detection of ascorbic acid and dopamine. The eye-ball detection limit for ascorbic acid and dopamine was 17.6 mg L-1 and 18.9 mg L-1, respectively. The test strip was selective for dopamine, but the detection of ascorbic acid suffered from interference by glutathione. The application of the test strips was nevertheless demonstrated by the detection of ascorbic acid in fruit juices and dopamine in fortified urine. The developed test strips employing the three approaches were applied without sample pre-treatment and use of supporting equipment.
- Full Text:
- Date Issued: 2014
Electrospun nanofibers as solid phase extraction sorbents and support for alkylphenols colorimetric probes
- Authors: Tancu, Yolanda
- Date: 2014
- Subjects: Nanofibers , Electrospinning , Extraction (Chemistry) , Sorbents , Phenols , Colorimetry , Transmission electron microscopy , High resolution spectroscopy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4486 , http://hdl.handle.net/10962/d1012997
- Description: The thesis reports on fabricating alternative solid phase extraction (SPE) sorbents and colorimetric probes based on electrospun nanofibers for alkylphenols (APs). Hydroxyl methylated styrene [poly(co-styrene-CH₃OH)] and 3-oxobutanoate styrene [poly(co-styrene-OCOCH₃COCH₃)] copolymers were synthesized and fabricated into sorbent materials by electro-spinning/spraying. The fabricated morphologies consisting of bead free fibers, beaded fibers and particles were evaluated as SPE sorbents using batch experiments. Electropun fibers proved to be better sorbents as they exhibited extraction efficiency that exceeded 95% compared to 60% for beaded fibers and 40% for particles. In view to reduce sample and solvent volumes, smooth fibers were packed into pipette tips as SPE devices that yielded quantitative recoveries of APs from spiked wastewater samples. Recoveries ranged from 70% to 125% with LOD of 0.008, 0.01 and 0.1 μg mL⁻¹ for 4-tert octylphenol (4-t-OP), 4-octylphenol (4-OP) and 4-nonylphenol (4-NP) respectively, when using high performance liquid chromatography-fluorescence detector (HPLC-FLD). Furthermore, amino functionalised polydiacetylene polymers (PDAs), citrate capped gold (AuNPs) and silver nanoparticles (AgNPs) were evaluated as colorimetric probes for visual detection of APs. In colloidal studies, AuNPs probe showed a colour change from wine red to green upon introduction of analyte. UV-vis spectroscopy revealed the shifting of the surface plasmon resonance (SPR) peak from 525 nm to 729 nm induced by aggregation of AuNPs. For AgNPs probe, a colour change was observed from yellowish green to brown. Transmission electron microscopy (TEM) studies showed growth of AgNPs. A presumed oxidation of the analyte, forming an absorbing compound at 279 nm in both AgNPs and PDAs probes was also observed. For PDAs probe the colour change was from purple to pink. Concentrations as low as 30 μg mL⁻¹ were detectable in all colloidal based probes. Further colorimetric investigations were conducted with electrospun AuNPs-nylon 6 fiber mat. A colour change from purplish red to navy blue at concentrations of 1000 μg mL⁻¹ was observed. Electrospun AgNPs –nylon 6 fiber mat did not show a distinct colour change. High resolution scanning electron microscopy (HRSEM) revealed the analyte inducing the assembly of AuNPs and AgNPs as they covered the surface of the nanofiber mat. Electrospun nanofibers are a platform for analysis and thus tuning their chemistry will lead to sensitive and selective methods
- Full Text:
- Date Issued: 2014
- Authors: Tancu, Yolanda
- Date: 2014
- Subjects: Nanofibers , Electrospinning , Extraction (Chemistry) , Sorbents , Phenols , Colorimetry , Transmission electron microscopy , High resolution spectroscopy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4486 , http://hdl.handle.net/10962/d1012997
- Description: The thesis reports on fabricating alternative solid phase extraction (SPE) sorbents and colorimetric probes based on electrospun nanofibers for alkylphenols (APs). Hydroxyl methylated styrene [poly(co-styrene-CH₃OH)] and 3-oxobutanoate styrene [poly(co-styrene-OCOCH₃COCH₃)] copolymers were synthesized and fabricated into sorbent materials by electro-spinning/spraying. The fabricated morphologies consisting of bead free fibers, beaded fibers and particles were evaluated as SPE sorbents using batch experiments. Electropun fibers proved to be better sorbents as they exhibited extraction efficiency that exceeded 95% compared to 60% for beaded fibers and 40% for particles. In view to reduce sample and solvent volumes, smooth fibers were packed into pipette tips as SPE devices that yielded quantitative recoveries of APs from spiked wastewater samples. Recoveries ranged from 70% to 125% with LOD of 0.008, 0.01 and 0.1 μg mL⁻¹ for 4-tert octylphenol (4-t-OP), 4-octylphenol (4-OP) and 4-nonylphenol (4-NP) respectively, when using high performance liquid chromatography-fluorescence detector (HPLC-FLD). Furthermore, amino functionalised polydiacetylene polymers (PDAs), citrate capped gold (AuNPs) and silver nanoparticles (AgNPs) were evaluated as colorimetric probes for visual detection of APs. In colloidal studies, AuNPs probe showed a colour change from wine red to green upon introduction of analyte. UV-vis spectroscopy revealed the shifting of the surface plasmon resonance (SPR) peak from 525 nm to 729 nm induced by aggregation of AuNPs. For AgNPs probe, a colour change was observed from yellowish green to brown. Transmission electron microscopy (TEM) studies showed growth of AgNPs. A presumed oxidation of the analyte, forming an absorbing compound at 279 nm in both AgNPs and PDAs probes was also observed. For PDAs probe the colour change was from purple to pink. Concentrations as low as 30 μg mL⁻¹ were detectable in all colloidal based probes. Further colorimetric investigations were conducted with electrospun AuNPs-nylon 6 fiber mat. A colour change from purplish red to navy blue at concentrations of 1000 μg mL⁻¹ was observed. Electrospun AgNPs –nylon 6 fiber mat did not show a distinct colour change. High resolution scanning electron microscopy (HRSEM) revealed the analyte inducing the assembly of AuNPs and AgNPs as they covered the surface of the nanofiber mat. Electrospun nanofibers are a platform for analysis and thus tuning their chemistry will lead to sensitive and selective methods
- Full Text:
- Date Issued: 2014
Electrospun sorbents for solid phase extraction (SPE) and colorimetric detection of pesticides
- Authors: Gulamussen, Noor Jehan
- Date: 2014
- Subjects: Sorbents , Electrospinning , Extraction (Chemistry) , Colorimetry , Pesticides , Water -- Pesticide content -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4501 , http://hdl.handle.net/10962/d1013241
- Description: The thesis presents the evaluation of polysulfone sorbents for solid phase extraction (SPE) and the development of colorimetric probes for pesticides analysis in water. Through electrospraying and electrospinning techniques, different morphologies of sorbents (particles, beaded fibers and bead-free fibers) were fabricated. The sorbents were morphologically characterized by scanning electron microscopy. Adsorption capacities of sorbents were evaluated by conducting recoveries studies for model pesticides; atrazine, chlorpyrifos and DDT using batch and column SPE modes. Better recovery results were achieved by employing the batch mode of fibers, as values ranged from 98 to 105percent. Further sorbent evaluation was conducted using breakthrough experiments and static experiments. The breakthrough studies indicated that 1700 μL was the sample volume that could be percolated with no breakthrough of the analyte that correspond to a concentration of 150 mg/g of sorbent that can be extracted without any loss of analyte. From static studies, quantities of each model compound adsorbed into the fiber at the equilibrium time were evaluated. The adsorbed atrazine was 65, chlorpyrifos 250 and DDT 400 mg/g of sorbent. Kinetic studies suggested retention mechanism following pseudo first and second order model observed by high correlation coefficients (> 0. 96), demonstrating the fiber affinity to retain both polar and non-polar compounds opening a possibility to be used as sorbent for sample preparation of different classes of pesticides in water. For the second part of the study simple strategies for colorimetric sensing based on silver nanoparticles and polivinylpyrrolidone capped nanoparticles were developed, respectively for atrazine and chlorpyrifos detection. The limits of detection of the methods were 3.32 and 0.88 mg/L for atrazine and chlorpyrifos respectively. The applicability of the probe in real samples was demonstrated by the recoveries studies of tap water varying from 94 to 104 percent. The versatility of the probe was demonstrated by affording a simple, rapid and selective detection of atrazine and chlorpyrifos in the presence of other pesticides by direct analysis without employing any sample handling steps. Attempt to incorporate the probes in a solid support was achieved by using nylon 6 as solid support polymer proving to be fast and useful for on-site detection.
- Full Text:
- Date Issued: 2014
- Authors: Gulamussen, Noor Jehan
- Date: 2014
- Subjects: Sorbents , Electrospinning , Extraction (Chemistry) , Colorimetry , Pesticides , Water -- Pesticide content -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4501 , http://hdl.handle.net/10962/d1013241
- Description: The thesis presents the evaluation of polysulfone sorbents for solid phase extraction (SPE) and the development of colorimetric probes for pesticides analysis in water. Through electrospraying and electrospinning techniques, different morphologies of sorbents (particles, beaded fibers and bead-free fibers) were fabricated. The sorbents were morphologically characterized by scanning electron microscopy. Adsorption capacities of sorbents were evaluated by conducting recoveries studies for model pesticides; atrazine, chlorpyrifos and DDT using batch and column SPE modes. Better recovery results were achieved by employing the batch mode of fibers, as values ranged from 98 to 105percent. Further sorbent evaluation was conducted using breakthrough experiments and static experiments. The breakthrough studies indicated that 1700 μL was the sample volume that could be percolated with no breakthrough of the analyte that correspond to a concentration of 150 mg/g of sorbent that can be extracted without any loss of analyte. From static studies, quantities of each model compound adsorbed into the fiber at the equilibrium time were evaluated. The adsorbed atrazine was 65, chlorpyrifos 250 and DDT 400 mg/g of sorbent. Kinetic studies suggested retention mechanism following pseudo first and second order model observed by high correlation coefficients (> 0. 96), demonstrating the fiber affinity to retain both polar and non-polar compounds opening a possibility to be used as sorbent for sample preparation of different classes of pesticides in water. For the second part of the study simple strategies for colorimetric sensing based on silver nanoparticles and polivinylpyrrolidone capped nanoparticles were developed, respectively for atrazine and chlorpyrifos detection. The limits of detection of the methods were 3.32 and 0.88 mg/L for atrazine and chlorpyrifos respectively. The applicability of the probe in real samples was demonstrated by the recoveries studies of tap water varying from 94 to 104 percent. The versatility of the probe was demonstrated by affording a simple, rapid and selective detection of atrazine and chlorpyrifos in the presence of other pesticides by direct analysis without employing any sample handling steps. Attempt to incorporate the probes in a solid support was achieved by using nylon 6 as solid support polymer proving to be fast and useful for on-site detection.
- Full Text:
- Date Issued: 2014
Electro‐oxidation of acetaminophen on nickel/poly (o‐aminophenol)/multi‐walled carbon nanotube nanocomposite modified graphite electrode.
- Naeemy, Ali, Mohammadi, Ali, Bakhtiari, Hediech, Ashouri, Nasim, Walker, Roderick B
- Authors: Naeemy, Ali , Mohammadi, Ali , Bakhtiari, Hediech , Ashouri, Nasim , Walker, Roderick B
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184107 , vital:44173 , xlink:href="https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/mnl.2014.0197"
- Description: Poly(o-aminophenol) (POAP)/multi-walled carbon nanotube (MWCNT) nanocomposite and POAP in the absence of the MWCNT were fabricated by consecutive cyclic voltammetry (CV) on a graphite (G) electrode. The dispersion of nickel (II) ions was accomplished and incorporated into the polymeric electrodes (G/POAP and G/POAP-MWCNT) by immersing them into a 0.1 M nickel (II) solution. Following preparation of G/POAP/Ni and G/POAP-MWCNT/Ni, the electrochemical behaviour was examined using CV. Scanning electron microscopy was used for characterisation of the nanocomposite. The prepared electrodes showed enhanced electrocatalytic activity for the oxidation of acetaminophen and facilitated the detection of acetaminophen in a 0.1 M NaOH solution. Compared with the G/POAP/Ni electrode, the G/POAP-MWCNT/Ni electrode had a significant current response of acetaminophen oxidation because of the synergistic effects of POAP and the MWCNT. By CV, the calibration plot was linear in the range of 1–13 mM with standard deviation between 0.3 and 6.54% for acetaminophen. The G/POAP-MWCNT/Ni was successfully applied for acetaminophen determination in tablets and the results showed sufficient precision and achieved a mean recovery of 96.8% (R.S.D. = 4.9%).
- Full Text:
- Date Issued: 2014
- Authors: Naeemy, Ali , Mohammadi, Ali , Bakhtiari, Hediech , Ashouri, Nasim , Walker, Roderick B
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184107 , vital:44173 , xlink:href="https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/mnl.2014.0197"
- Description: Poly(o-aminophenol) (POAP)/multi-walled carbon nanotube (MWCNT) nanocomposite and POAP in the absence of the MWCNT were fabricated by consecutive cyclic voltammetry (CV) on a graphite (G) electrode. The dispersion of nickel (II) ions was accomplished and incorporated into the polymeric electrodes (G/POAP and G/POAP-MWCNT) by immersing them into a 0.1 M nickel (II) solution. Following preparation of G/POAP/Ni and G/POAP-MWCNT/Ni, the electrochemical behaviour was examined using CV. Scanning electron microscopy was used for characterisation of the nanocomposite. The prepared electrodes showed enhanced electrocatalytic activity for the oxidation of acetaminophen and facilitated the detection of acetaminophen in a 0.1 M NaOH solution. Compared with the G/POAP/Ni electrode, the G/POAP-MWCNT/Ni electrode had a significant current response of acetaminophen oxidation because of the synergistic effects of POAP and the MWCNT. By CV, the calibration plot was linear in the range of 1–13 mM with standard deviation between 0.3 and 6.54% for acetaminophen. The G/POAP-MWCNT/Ni was successfully applied for acetaminophen determination in tablets and the results showed sufficient precision and achieved a mean recovery of 96.8% (R.S.D. = 4.9%).
- Full Text:
- Date Issued: 2014
Elephants in Africa: Big, grey biodiversity thieves?
- Kuiper, Timothy R, Parker, Daniel M
- Authors: Kuiper, Timothy R , Parker, Daniel M
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124385 , vital:35601 , https://doi.org/10.2989/16085914.2011.589120
- Description: The conservation of biological diversity is one of the greatest challenges facing humanity today.1,2 Addressing this challenge must inevitably involve the maintenance of the composition, structure and functioning of multi-species ecosystems.2-4 While preventing the loss of particular species is an obvious strategy, a second goal might be to manage for local species diversity and the heterogeneity of habitats.5 A further objective may be the restoration of damaged ecosystems.6 Large herbivore assemblages form an important component of many diverse ecosystems and are of distinct ecological, and hence conservation, value.7-9 On the other hand, herbivores managed at unnaturally high densities may drive detrimental changes in the structural heterogeneity of habitats.10-12 Thus, decision-makers are faced with the challenge of balancing the needs of populations of large herbivores with the preservation of vegetation and ecosystem diversity.9 In light of these considerations, conclusions as to whether large herbivores are ‘good’ or ‘bad’ for biological diversity are both contentious and elusive. Nonetheless, we seek to explore this question with particular reference to African savannah elephants (Loxodonta africana). We discuss whether or not the elephant should be considered a biodiversity thief – a species that upsets the natural diversity of life in the habitat in which it lives.
- Full Text:
- Date Issued: 2014
- Authors: Kuiper, Timothy R , Parker, Daniel M
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124385 , vital:35601 , https://doi.org/10.2989/16085914.2011.589120
- Description: The conservation of biological diversity is one of the greatest challenges facing humanity today.1,2 Addressing this challenge must inevitably involve the maintenance of the composition, structure and functioning of multi-species ecosystems.2-4 While preventing the loss of particular species is an obvious strategy, a second goal might be to manage for local species diversity and the heterogeneity of habitats.5 A further objective may be the restoration of damaged ecosystems.6 Large herbivore assemblages form an important component of many diverse ecosystems and are of distinct ecological, and hence conservation, value.7-9 On the other hand, herbivores managed at unnaturally high densities may drive detrimental changes in the structural heterogeneity of habitats.10-12 Thus, decision-makers are faced with the challenge of balancing the needs of populations of large herbivores with the preservation of vegetation and ecosystem diversity.9 In light of these considerations, conclusions as to whether large herbivores are ‘good’ or ‘bad’ for biological diversity are both contentious and elusive. Nonetheless, we seek to explore this question with particular reference to African savannah elephants (Loxodonta africana). We discuss whether or not the elephant should be considered a biodiversity thief – a species that upsets the natural diversity of life in the habitat in which it lives.
- Full Text:
- Date Issued: 2014
Elephants in Africa: Big, grey biodiversity thieves?
- Kuiper, T R, Parker, Daniel M
- Authors: Kuiper, T R , Parker, Daniel M
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69886 , vital:29591 , http://dx.doi.org/10.1590/ sajs.2014/a0058
- Description: The conservation of biological diversity is one of the greatest challenges facing humanity today.1,2 Addressing this challenge must inevitably involve the maintenance of the composition, structure and functioning of multi-species ecosystems.2-4 While preventing the loss of particular species is an obvious strategy, a second goal might be to manage for local species diversity and the heterogeneity of habitats.5 A further objective may be the restoration of damaged ecosystems.6 Large herbivore assemblages form an important component of many diverse ecosystems and are of distinct ecological, and hence conservation, value.7-9 On the other hand, herbivores managed at unnaturally high densities may drive detrimental changes in the structural heterogeneity of habitats.10-12 Thus, decision-makers are faced with the challenge of balancing the needs of populations of large herbivores with the preservation of vegetation and ecosystem diversity.9 In light of these considerations, conclusions as to whether large herbivores are 'good' or 'bad' for biological diversity are both contentious and elusive. Nonetheless, we seek to explore this question with particular reference to African savannah elephants (Loxodonta africana). We discuss whether or not the elephant should be considered a biodiversity thief - a species that upsets the natural diversity of life in the habitat in which it lives. The African elephant has been driven to local extinction over much of its former range, with hunting for meat and ivory and the conversion of elephant habitat to agriculture constituting the major drivers.5 Given the historical decline in elephant numbers, the conservation of this species appears to be a sensible objective.9,13 However, the protection afforded to elephants in confined (usually fenced) reserves across Africa has distinct implications for the management of local species diversity and the heterogeneity of habitats.14,15 Elephants have been shown to have clear impacts on the structure of vegetation, particularly in woodland habitats12,16,17, and these changes may have knock-on effects for sympatric species10,18,19. The effects of elephants on biological diversity in protected areas are of particular concern in light of how expansion in human populations, and the land-use change that follows, places increasing pressure on reserves to preserve biological diversity.9,10. Change within ecosystems is natural and inevitable and large herbivores have been living in an ever-changing environment for millions of years.20 Changes brought on by elephants, therefore, should not automatically be categorised as undesirable, and short-term changes may be part of an overarching trend of long-term stability.8,21 Furthermore, current elephant impacts can only be adequately assessed in the light of historical (on the scale of centuries) benchmarks, for which accurate information is notoriously scant.10,21 The current impacts of elephant populations on vegetation dynamics in some regions may in fact represent a shift towards a more natural historical state.8,21 Finally, much of the detrimental impacts of elephants on habitat structure and diversity, particularly at smaller scales, has resulted from human interventions (such as the erection of fences and the establishment of artificial water points) that have unnaturally confined elephants to localised areas, disrupted seasonal movements and disturbed the natural dynamics of population processes.5,13,22.
- Full Text:
- Date Issued: 2014
- Authors: Kuiper, T R , Parker, Daniel M
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69886 , vital:29591 , http://dx.doi.org/10.1590/ sajs.2014/a0058
- Description: The conservation of biological diversity is one of the greatest challenges facing humanity today.1,2 Addressing this challenge must inevitably involve the maintenance of the composition, structure and functioning of multi-species ecosystems.2-4 While preventing the loss of particular species is an obvious strategy, a second goal might be to manage for local species diversity and the heterogeneity of habitats.5 A further objective may be the restoration of damaged ecosystems.6 Large herbivore assemblages form an important component of many diverse ecosystems and are of distinct ecological, and hence conservation, value.7-9 On the other hand, herbivores managed at unnaturally high densities may drive detrimental changes in the structural heterogeneity of habitats.10-12 Thus, decision-makers are faced with the challenge of balancing the needs of populations of large herbivores with the preservation of vegetation and ecosystem diversity.9 In light of these considerations, conclusions as to whether large herbivores are 'good' or 'bad' for biological diversity are both contentious and elusive. Nonetheless, we seek to explore this question with particular reference to African savannah elephants (Loxodonta africana). We discuss whether or not the elephant should be considered a biodiversity thief - a species that upsets the natural diversity of life in the habitat in which it lives. The African elephant has been driven to local extinction over much of its former range, with hunting for meat and ivory and the conversion of elephant habitat to agriculture constituting the major drivers.5 Given the historical decline in elephant numbers, the conservation of this species appears to be a sensible objective.9,13 However, the protection afforded to elephants in confined (usually fenced) reserves across Africa has distinct implications for the management of local species diversity and the heterogeneity of habitats.14,15 Elephants have been shown to have clear impacts on the structure of vegetation, particularly in woodland habitats12,16,17, and these changes may have knock-on effects for sympatric species10,18,19. The effects of elephants on biological diversity in protected areas are of particular concern in light of how expansion in human populations, and the land-use change that follows, places increasing pressure on reserves to preserve biological diversity.9,10. Change within ecosystems is natural and inevitable and large herbivores have been living in an ever-changing environment for millions of years.20 Changes brought on by elephants, therefore, should not automatically be categorised as undesirable, and short-term changes may be part of an overarching trend of long-term stability.8,21 Furthermore, current elephant impacts can only be adequately assessed in the light of historical (on the scale of centuries) benchmarks, for which accurate information is notoriously scant.10,21 The current impacts of elephant populations on vegetation dynamics in some regions may in fact represent a shift towards a more natural historical state.8,21 Finally, much of the detrimental impacts of elephants on habitat structure and diversity, particularly at smaller scales, has resulted from human interventions (such as the erection of fences and the establishment of artificial water points) that have unnaturally confined elephants to localised areas, disrupted seasonal movements and disturbed the natural dynamics of population processes.5,13,22.
- Full Text:
- Date Issued: 2014
Embracing racial reasoning: the DASO poster controversy and ‘Race’politics in contemporary South Africa
- Vincent, Louise, Howell, Simon
- Authors: Vincent, Louise , Howell, Simon
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141933 , vital:38017 , DOI: 10.1080/03057070.2014.877651
- Description: We examine the response to a poster published by South Africa's official opposition's youth wing, the Democratic Alliance's Student Organisation (DASO) as part of a political campaign in 2012. From commentary that the poster's publication generated, we excavate some of the key discursive strategies used by commentators to negotiate the gulf between the constitutional value of non-racialism and the lived contemporary reality of race in South Africa. Many commentators situated themselves either as ‘colour-blind’, or reformulated ‘race’ as ‘class’ or ‘culture’. In making visible some of these strategies, and the attendant (re-)racialised narratives upon which they rely, we highlight the paradoxes that inhere in the idea of ‘non-racialism’ – a notion that implies that race must simultaneously be thought and ‘un-thought’. Racial categories contrived by apartheid have been somewhat rearranged and rearticulated, but nevertheless continue to operate today as organising principles.
- Full Text:
- Date Issued: 2014
- Authors: Vincent, Louise , Howell, Simon
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141933 , vital:38017 , DOI: 10.1080/03057070.2014.877651
- Description: We examine the response to a poster published by South Africa's official opposition's youth wing, the Democratic Alliance's Student Organisation (DASO) as part of a political campaign in 2012. From commentary that the poster's publication generated, we excavate some of the key discursive strategies used by commentators to negotiate the gulf between the constitutional value of non-racialism and the lived contemporary reality of race in South Africa. Many commentators situated themselves either as ‘colour-blind’, or reformulated ‘race’ as ‘class’ or ‘culture’. In making visible some of these strategies, and the attendant (re-)racialised narratives upon which they rely, we highlight the paradoxes that inhere in the idea of ‘non-racialism’ – a notion that implies that race must simultaneously be thought and ‘un-thought’. Racial categories contrived by apartheid have been somewhat rearranged and rearticulated, but nevertheless continue to operate today as organising principles.
- Full Text:
- Date Issued: 2014
Empathetic apprentice: pedagogical developments in aesthetic education of the social learning practitioner in South Africa
- Authors: McGarry, Dylan K
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/437176 , vital:73350 , ISBN 978-9086862528 , https://doi.org/10.3920/978-90-8686-802-5_12
- Description: Apprenticeship is an ancient and intuitive approach to learning, yet today traditional forms of apprenticeship are becoming in-creasingly scarce. The role of apprenticeship in relation to learning through embodied, first hand experience is somewhat overlooked, particularly in the the pedagogical development of social learning. Understanding this in my early doctoral re-search, I focused on the process of apprenticeship and its contribution to social learning practice. I moved beyond the concept of traditional apprenticeship (that of learning a specific artisan practice) and explored the possibility of sharpening my capacities as an ‘ecological-citizen’; expanding Education for Sustainable Development (ESD) concepts, and investigating a wider embodied learning of a citizen situated in a greater social-ecological phenomenon.
- Full Text:
- Date Issued: 2014
- Authors: McGarry, Dylan K
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/437176 , vital:73350 , ISBN 978-9086862528 , https://doi.org/10.3920/978-90-8686-802-5_12
- Description: Apprenticeship is an ancient and intuitive approach to learning, yet today traditional forms of apprenticeship are becoming in-creasingly scarce. The role of apprenticeship in relation to learning through embodied, first hand experience is somewhat overlooked, particularly in the the pedagogical development of social learning. Understanding this in my early doctoral re-search, I focused on the process of apprenticeship and its contribution to social learning practice. I moved beyond the concept of traditional apprenticeship (that of learning a specific artisan practice) and explored the possibility of sharpening my capacities as an ‘ecological-citizen’; expanding Education for Sustainable Development (ESD) concepts, and investigating a wider embodied learning of a citizen situated in a greater social-ecological phenomenon.
- Full Text:
- Date Issued: 2014
Empathy in the time of ecological apartheid : a social sculpture practice-led inquiry into developing pedagogies for ecological citizenship
- Authors: McGarry, Dylan Kenneth
- Date: 2014
- Subjects: Education -- Philosophy , Social learning , Environmental education , Arts in education
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1985 , http://hdl.handle.net/10962/d1013154
- Description: Considering the ecological crisis and the increased disconnection between human beings and nature, this study attempts to find the social and aesthetic educational response needed for developing ecological citizenship for the 21st century. In this transdisciplinary study I articulate what at first seems a clumsy attempt to enable the capacities of the embodied ecological citizen, and which later emerges as an alchemical ‘social sculpture’ approach to learning that expands the range of capacities available to the citizen and the citizen’s immediate community. This learning bridges the gap between purely biocentric and technocentric forms of education, and addresses the ambiguity of concepts and forms of action such as ‘sustainability’. My primary focus is enabling both communal and personal forms of agency: new ways of 'doing’ and 'being' in the world as it changes radically. I argue that this demands constantly reflecting on and engaging without understanding, place and perception of the problems we see. Attending to a call for the importance of complex learning processes, that deepens our understanding of sustainability, and the need for methodological and pedagogical approaches to accessible forms of learning socially in the era of climate change and environmental degradation, this study offers a particular insight into the education of an ecological citizen. In particular I examine a form of learning that enables individuals to explore relationships between themselves and their ecologies (both physical and social), and that encourages personal forms of knowing so that each person’s values can be cultivated within the experience and intuitive expression from both inner and outer realities. Central to my research focus is addressing the difficulties inherent in ‘ecological apartheid’, which is defined as a growing separation of relationships that include the human being’s relationship with the natural world, as well as disconnections experienced within one’s own inner and outer capacities. Subsequently I investigate forms of learning that encourage agency that most appropriately enable citizens to respond personally to both inner and outer forms of disconnection. ‘Personal’ and ‘relational agency’ are defined and investigated through an initial twelve-month collaborative participatory contextual profiling exploratory research period in South Africa (phase A), where I explore various forms of multiple-genre creative social learning practice that develop an accessible set of methodologies and pedagogies for the ecological citizen. Through this exploratory research, I place significance in the relatively unknown field of social sculpture, which I investigate through a self-made apprenticeship with Shelley Sacks, an expert in the field. This is documented through a rigorous ethnographic inquiry over a period of 18 months. Following this I undertake another two-year collaborative, practice-based research study across South Africa (phase B: 17 towns, with a total of 350 citizens) and eventually abroad (United Kingdom, Germany, USA and Belgium).The focus of this study was the implementation of a collaboratively developed citizen learning practice entitled Earth Forum developed by Shelley Sacks as a progression from her work “Exchange Values: voices of insivible lives” and my collaboative exploration into Earth Forum and its further development draws heavily from social sculpture methods obtained during the apprenticeship, and applied in 36 different incidences. I further explore the efficacy of this practice in enabling and expanding the capacities of participants, particularly those that encourage the development of personal and relational agency. This was achieved through a pedagogical development and expansion period (phase C). A primary finding through the iterative phase (phase D) was the value of imaginal contemplation, attentive listening, and empathy as capacities that enable an ecological citizen’s overall capability. I ascribed this to Nussbaum and Sen’s (1993) capability theory and the need to enable the articulation and implementation of a citizen’s valued ‘beings and doings’. Through this iterative phase, specific attention is given to listening and intuitive capacities in enabling personal and relational agency, and specifically I observed the fundamental role of imagination in this form of learning. Particularly valuable for the educational contribution of this study is the pedagogical development of the Earth Forum practice that enables an accessible, socially constructed form of learning. This contributes specifically to exploring ‘how’ social learning is undertaken, and I argue that an aesthetic approach to learning is vital for the education of the ecological citizen. I carefully describe how one can conduct collaborative practice-based research that utilises creative connective practice in agency development. This collaborative approach, with regard to learning socially and capacity development for ecological citizenship (that focuses its attention on addressing ecological apartheid and separateness), is articulated through a multiple-genred text. I found that empathetic capacity in ecological citizen education is relatively unexplored, and within listening and as well in empathy theory, that the role of imagination in listening and empathy development, requires greater attention. I attempt to reveal how connective practice considers aesthetic form and shape in expanding capacities of human beings, and introduce novel expanded forms of developing pedagogies that encourage personal and relational agency in the context of ecological apartheid from the artsbased field of social sculpture. Finally, I aim in this study to share the potential value found in social sculpture theory and practice into the field of environmental education and social learning through a reflection on the current context of education and social learning, and its potential enrichment via social sculpture processes.
- Full Text:
- Date Issued: 2014
- Authors: McGarry, Dylan Kenneth
- Date: 2014
- Subjects: Education -- Philosophy , Social learning , Environmental education , Arts in education
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1985 , http://hdl.handle.net/10962/d1013154
- Description: Considering the ecological crisis and the increased disconnection between human beings and nature, this study attempts to find the social and aesthetic educational response needed for developing ecological citizenship for the 21st century. In this transdisciplinary study I articulate what at first seems a clumsy attempt to enable the capacities of the embodied ecological citizen, and which later emerges as an alchemical ‘social sculpture’ approach to learning that expands the range of capacities available to the citizen and the citizen’s immediate community. This learning bridges the gap between purely biocentric and technocentric forms of education, and addresses the ambiguity of concepts and forms of action such as ‘sustainability’. My primary focus is enabling both communal and personal forms of agency: new ways of 'doing’ and 'being' in the world as it changes radically. I argue that this demands constantly reflecting on and engaging without understanding, place and perception of the problems we see. Attending to a call for the importance of complex learning processes, that deepens our understanding of sustainability, and the need for methodological and pedagogical approaches to accessible forms of learning socially in the era of climate change and environmental degradation, this study offers a particular insight into the education of an ecological citizen. In particular I examine a form of learning that enables individuals to explore relationships between themselves and their ecologies (both physical and social), and that encourages personal forms of knowing so that each person’s values can be cultivated within the experience and intuitive expression from both inner and outer realities. Central to my research focus is addressing the difficulties inherent in ‘ecological apartheid’, which is defined as a growing separation of relationships that include the human being’s relationship with the natural world, as well as disconnections experienced within one’s own inner and outer capacities. Subsequently I investigate forms of learning that encourage agency that most appropriately enable citizens to respond personally to both inner and outer forms of disconnection. ‘Personal’ and ‘relational agency’ are defined and investigated through an initial twelve-month collaborative participatory contextual profiling exploratory research period in South Africa (phase A), where I explore various forms of multiple-genre creative social learning practice that develop an accessible set of methodologies and pedagogies for the ecological citizen. Through this exploratory research, I place significance in the relatively unknown field of social sculpture, which I investigate through a self-made apprenticeship with Shelley Sacks, an expert in the field. This is documented through a rigorous ethnographic inquiry over a period of 18 months. Following this I undertake another two-year collaborative, practice-based research study across South Africa (phase B: 17 towns, with a total of 350 citizens) and eventually abroad (United Kingdom, Germany, USA and Belgium).The focus of this study was the implementation of a collaboratively developed citizen learning practice entitled Earth Forum developed by Shelley Sacks as a progression from her work “Exchange Values: voices of insivible lives” and my collaboative exploration into Earth Forum and its further development draws heavily from social sculpture methods obtained during the apprenticeship, and applied in 36 different incidences. I further explore the efficacy of this practice in enabling and expanding the capacities of participants, particularly those that encourage the development of personal and relational agency. This was achieved through a pedagogical development and expansion period (phase C). A primary finding through the iterative phase (phase D) was the value of imaginal contemplation, attentive listening, and empathy as capacities that enable an ecological citizen’s overall capability. I ascribed this to Nussbaum and Sen’s (1993) capability theory and the need to enable the articulation and implementation of a citizen’s valued ‘beings and doings’. Through this iterative phase, specific attention is given to listening and intuitive capacities in enabling personal and relational agency, and specifically I observed the fundamental role of imagination in this form of learning. Particularly valuable for the educational contribution of this study is the pedagogical development of the Earth Forum practice that enables an accessible, socially constructed form of learning. This contributes specifically to exploring ‘how’ social learning is undertaken, and I argue that an aesthetic approach to learning is vital for the education of the ecological citizen. I carefully describe how one can conduct collaborative practice-based research that utilises creative connective practice in agency development. This collaborative approach, with regard to learning socially and capacity development for ecological citizenship (that focuses its attention on addressing ecological apartheid and separateness), is articulated through a multiple-genred text. I found that empathetic capacity in ecological citizen education is relatively unexplored, and within listening and as well in empathy theory, that the role of imagination in listening and empathy development, requires greater attention. I attempt to reveal how connective practice considers aesthetic form and shape in expanding capacities of human beings, and introduce novel expanded forms of developing pedagogies that encourage personal and relational agency in the context of ecological apartheid from the artsbased field of social sculpture. Finally, I aim in this study to share the potential value found in social sculpture theory and practice into the field of environmental education and social learning through a reflection on the current context of education and social learning, and its potential enrichment via social sculpture processes.
- Full Text:
- Date Issued: 2014
Employees' perceptions of the South African Police Service's employee substance abuse prevention programme in Port Elizabeth
- Authors: Smith, Janine
- Date: 2014
- Subjects: Employee assistance programs -- South Africa -- Port Elizabeth , Substance abuse -- Prevention
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10009 , http://hdl.handle.net/10948/d1021183
- Description: Substance abuse is a major social issue within the South African Police Service (SAPS). To address this issue, the SAPS implement an Employee Assistance Programme (EAP) as an intervention to address problems that may affect the work performance of employees. Despite the existence of this programme, substance abuse is still occurring and has a negative impact on work performance. This concern has fuelled the researcher to initiate this study. The goal of this study is to gain an understanding of Port Elizabeth SAPS employees’ perceptions regarding the effectiveness of the EAP substance abuse prevention programme. A qualitative research methodology, with a descriptive, exploratory and contextual research design was implemented. The researcher elected to use non-probability sampling, specifically, purposive sampling for this study. A sample of ten employees was chosen from an area demarcated for the purpose of the study, within the SAPS in Port Elizabeth. Data was collected through semi-structured, individual interviews. Interviews were continued until saturation point was reached. The interviews were analyzed according to the detailed guidelines set out by Tesch (in Creswell, 2003:192). The data was verified according to Guba’s principles (in De Vos, Strydom, Fouche & Delport, 2002:351). The researcher also employed the services of an independent coder in order to enhance the trustworthiness of the study. The perceptions of EAP as a substance abuse prevention programme, by employees of the SAPS in Port Elizabeth, have not been highlighted adequately within the South African context. The researcher’s study will hence contribute to the existing body of knowledge of the discipline.
- Full Text:
- Date Issued: 2014
- Authors: Smith, Janine
- Date: 2014
- Subjects: Employee assistance programs -- South Africa -- Port Elizabeth , Substance abuse -- Prevention
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10009 , http://hdl.handle.net/10948/d1021183
- Description: Substance abuse is a major social issue within the South African Police Service (SAPS). To address this issue, the SAPS implement an Employee Assistance Programme (EAP) as an intervention to address problems that may affect the work performance of employees. Despite the existence of this programme, substance abuse is still occurring and has a negative impact on work performance. This concern has fuelled the researcher to initiate this study. The goal of this study is to gain an understanding of Port Elizabeth SAPS employees’ perceptions regarding the effectiveness of the EAP substance abuse prevention programme. A qualitative research methodology, with a descriptive, exploratory and contextual research design was implemented. The researcher elected to use non-probability sampling, specifically, purposive sampling for this study. A sample of ten employees was chosen from an area demarcated for the purpose of the study, within the SAPS in Port Elizabeth. Data was collected through semi-structured, individual interviews. Interviews were continued until saturation point was reached. The interviews were analyzed according to the detailed guidelines set out by Tesch (in Creswell, 2003:192). The data was verified according to Guba’s principles (in De Vos, Strydom, Fouche & Delport, 2002:351). The researcher also employed the services of an independent coder in order to enhance the trustworthiness of the study. The perceptions of EAP as a substance abuse prevention programme, by employees of the SAPS in Port Elizabeth, have not been highlighted adequately within the South African context. The researcher’s study will hence contribute to the existing body of knowledge of the discipline.
- Full Text:
- Date Issued: 2014
Employer liability for sexual harassment in the workplace revisited
- Authors: Raubenheimer, Heidi Leasel
- Date: 2014
- Subjects: Sexual harassment , Discrimination in employment
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:10271 , http://hdl.handle.net/10948/d1018607
- Description: Over the last two decades our courts have become inundated with cases relating to sexual harassment in the workplace. Sexual harassment has become a major problem in the workplace hence the decision by parliament and our courts to implement policies in the workplace to try and curb the problem. The effects of sexual harassment on a victims’ job and career can be profound. It has been proven that many employees simply decide to leave their jobs or to request a transfer than to endure the harassment until they are psychologically destroyed by the embarrassing situation.The Employment Equity Act explicitly in section 6 prohibits unfair discrimination in very specific terms. It states that no person may unfairly discriminate directly or indirectly against an employee in an employment policy or practice on one or more of the grounds listed in section 6. Section 6(3) further states that harassment of an employee is a form of discrimination where the harassment is based on any one or more of the grounds listed in section 6 (1) which includes sexual harassment. Section 60 deals with the liability of employees for the conduct of their employees committed whilst the employees are at work, where such conduct contravenes the provisions of the EEA. If the conduct is brought to the attention of the employer he or she is obliged to take the necessary steps to eliminate the alleged conduct and to comply with the provisions of the EEA. Section 60(3) renders an employee vicariously liable for the conduct of an employee who contravenes the provisions of the EEA. An employee who cannot prove that reasonable steps were taken to ensure that the provisions of the EEA are not contravened will be held liable for the actions or their employees. An employer who can prove that reasonable steps were taken will not be held liable for the actions of the employee.The provisions of the EEA were applied in the case of Ntsabo v Real Security wherein an employee had been sexually harassed over a period of six months by a fellow employee. The employee had reported the incidents of sexual harassment to the corporation she was employed with which failed to take action against the senior employee. Instead of taking action the corporation moved her to a different work station and placed her on night shift. This gave her the impression that she was being punished for the deed of the senior employee which resulted in her resigning from the corporation and instituting a claim for constructive dismissal and damages for sexual harassment. The court found that she had been constructively dismissed and that the senior employee had contravened section 6(3) of the EEA. The court further held that the employer (corporation) was also liable for the conduct of the senior employee in contravening the Act. In terms of the doctrine of vicarious liability on the other an employer may be held vicariously liable for the actions of its employees committed during the course and scope of their employment. The test for vicarious liability is therefore whether at the time of the alleged act of sexual harassment the employee was acting within the course and scope of his employment. The doctrine came before the court in the case of Grobler v Naspers. In this case Grobler who was employed at Naspers alleged that has had been sexually harassed by her immediate supervisor Mr Samuels. Samuels acted as trainee manager for seven months. Grobler suffered a mental breakdown as a result of the harassment and contented that she was no longer fit to work. She approached the High court for relief and alleged that Naspers (employer) was vicariously liable for the actions of Mr Samuels and the damages she suffered. In Naspers the court had to decide whether Samuels was indeed responsible for Grobler’s condition and if so whether Naspers were vicariously liable for his actions. In coming to its decision various cases were cited by the court as authority that recognised underlying policy considerations of vicarious liability. This included considerations that the employer is in a better position to pay compensation than the employee and to render the employer liable, serves as a deterrent against similar conduct in the future. The court also remarked that the common law courts acknowledge that the evolution of the doctrine continues to be guided by policy. The court ruled that policy considerations justified the finding that Naspers was vicariously liable for the sexual harassment of Grobler. It held further that both Naspers and Samuels were jointly and severally liable for the compensation to be paid. The Code of Good Practice on the Handling of Sexual Harassment Cases which was published as an annexure to the Labour Relations Act was implemented in an attempt to eliminate sexual harassment in the workplace, to provide appropriate procedures to deal with the problem and to prevent its occurrence and to promote and to encourage the development and implementation of policies and procedures which will assist in creating workplaces free from sexual harassment. The cases quoted above demonstrate the different approaches adopted by the courts in seeking to grant relief to victims of sexual harassment. It is clear that policies and procedures should be in place in the workplace that will ensure that employers are not held liable for the actions of their employees committed during the course and scope of employment. The same can however not be said when there are no policies and procedures in place in the workplace.
- Full Text:
- Date Issued: 2014
- Authors: Raubenheimer, Heidi Leasel
- Date: 2014
- Subjects: Sexual harassment , Discrimination in employment
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:10271 , http://hdl.handle.net/10948/d1018607
- Description: Over the last two decades our courts have become inundated with cases relating to sexual harassment in the workplace. Sexual harassment has become a major problem in the workplace hence the decision by parliament and our courts to implement policies in the workplace to try and curb the problem. The effects of sexual harassment on a victims’ job and career can be profound. It has been proven that many employees simply decide to leave their jobs or to request a transfer than to endure the harassment until they are psychologically destroyed by the embarrassing situation.The Employment Equity Act explicitly in section 6 prohibits unfair discrimination in very specific terms. It states that no person may unfairly discriminate directly or indirectly against an employee in an employment policy or practice on one or more of the grounds listed in section 6. Section 6(3) further states that harassment of an employee is a form of discrimination where the harassment is based on any one or more of the grounds listed in section 6 (1) which includes sexual harassment. Section 60 deals with the liability of employees for the conduct of their employees committed whilst the employees are at work, where such conduct contravenes the provisions of the EEA. If the conduct is brought to the attention of the employer he or she is obliged to take the necessary steps to eliminate the alleged conduct and to comply with the provisions of the EEA. Section 60(3) renders an employee vicariously liable for the conduct of an employee who contravenes the provisions of the EEA. An employee who cannot prove that reasonable steps were taken to ensure that the provisions of the EEA are not contravened will be held liable for the actions or their employees. An employer who can prove that reasonable steps were taken will not be held liable for the actions of the employee.The provisions of the EEA were applied in the case of Ntsabo v Real Security wherein an employee had been sexually harassed over a period of six months by a fellow employee. The employee had reported the incidents of sexual harassment to the corporation she was employed with which failed to take action against the senior employee. Instead of taking action the corporation moved her to a different work station and placed her on night shift. This gave her the impression that she was being punished for the deed of the senior employee which resulted in her resigning from the corporation and instituting a claim for constructive dismissal and damages for sexual harassment. The court found that she had been constructively dismissed and that the senior employee had contravened section 6(3) of the EEA. The court further held that the employer (corporation) was also liable for the conduct of the senior employee in contravening the Act. In terms of the doctrine of vicarious liability on the other an employer may be held vicariously liable for the actions of its employees committed during the course and scope of their employment. The test for vicarious liability is therefore whether at the time of the alleged act of sexual harassment the employee was acting within the course and scope of his employment. The doctrine came before the court in the case of Grobler v Naspers. In this case Grobler who was employed at Naspers alleged that has had been sexually harassed by her immediate supervisor Mr Samuels. Samuels acted as trainee manager for seven months. Grobler suffered a mental breakdown as a result of the harassment and contented that she was no longer fit to work. She approached the High court for relief and alleged that Naspers (employer) was vicariously liable for the actions of Mr Samuels and the damages she suffered. In Naspers the court had to decide whether Samuels was indeed responsible for Grobler’s condition and if so whether Naspers were vicariously liable for his actions. In coming to its decision various cases were cited by the court as authority that recognised underlying policy considerations of vicarious liability. This included considerations that the employer is in a better position to pay compensation than the employee and to render the employer liable, serves as a deterrent against similar conduct in the future. The court also remarked that the common law courts acknowledge that the evolution of the doctrine continues to be guided by policy. The court ruled that policy considerations justified the finding that Naspers was vicariously liable for the sexual harassment of Grobler. It held further that both Naspers and Samuels were jointly and severally liable for the compensation to be paid. The Code of Good Practice on the Handling of Sexual Harassment Cases which was published as an annexure to the Labour Relations Act was implemented in an attempt to eliminate sexual harassment in the workplace, to provide appropriate procedures to deal with the problem and to prevent its occurrence and to promote and to encourage the development and implementation of policies and procedures which will assist in creating workplaces free from sexual harassment. The cases quoted above demonstrate the different approaches adopted by the courts in seeking to grant relief to victims of sexual harassment. It is clear that policies and procedures should be in place in the workplace that will ensure that employers are not held liable for the actions of their employees committed during the course and scope of employment. The same can however not be said when there are no policies and procedures in place in the workplace.
- Full Text:
- Date Issued: 2014
Empowering educators to deal with challenging behaviour at high schools in poor socio-economic areas
- Authors: Forbes, Carine Madge Sybil
- Date: 2014
- Subjects: School discipline , High school teachers -- Economic conditions , High school teachers -- Social conditions , Children -- Conduct of life
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:9462 , http://hdl.handle.net/10948/d1020258
- Description: Inclusive education and the abolishment of corporal punishment by the National Department of Education have a profound influence on the behaviour of the learners in the classroom. Behaviour displayed by learners challenges the authority of educators and stand in direct contrast to a peaceful classroom setting which is a key element of the learning process. Educators found themselves at a loss, not knowing how to retain order and discipline while valuable teaching time is lost. The aim of this study is to identify and determine how educators can be empowered to deal with challenging behaviour in their high school classrooms. A qualitative study was conducted for this purpose, in four high schools which is situated in the Northern Areas of Port Elizabeth in the Eastern Cape. To obtain the necessary data different data-collection techniques were used, namely questionnaires and interviews. Learners, educators and parents were participants in the study. The findings suggested that most educators do not have the skills and/or knowledge to cope with challenging behaviour displayed by learners in the classroom. Conditions where educators are unable to control the behaviour of learners undoubtedly leads to the degradation of teaching and learning, so the need to address the problem was real. The concluding chapter recommends strategies of dealing with challenging behaviour through classroom management, educator skills as well as disciplinary strategies. An environment that is conducive for teaching and learning will be created by such strategies.
- Full Text:
- Date Issued: 2014
Empowering educators to deal with challenging behaviour at high schools in poor socio-economic areas
- Authors: Forbes, Carine Madge Sybil
- Date: 2014
- Subjects: School discipline , High school teachers -- Economic conditions , High school teachers -- Social conditions , Children -- Conduct of life
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:9462 , http://hdl.handle.net/10948/d1020258
- Description: Inclusive education and the abolishment of corporal punishment by the National Department of Education have a profound influence on the behaviour of the learners in the classroom. Behaviour displayed by learners challenges the authority of educators and stand in direct contrast to a peaceful classroom setting which is a key element of the learning process. Educators found themselves at a loss, not knowing how to retain order and discipline while valuable teaching time is lost. The aim of this study is to identify and determine how educators can be empowered to deal with challenging behaviour in their high school classrooms. A qualitative study was conducted for this purpose, in four high schools which is situated in the Northern Areas of Port Elizabeth in the Eastern Cape. To obtain the necessary data different data-collection techniques were used, namely questionnaires and interviews. Learners, educators and parents were participants in the study. The findings suggested that most educators do not have the skills and/or knowledge to cope with challenging behaviour displayed by learners in the classroom. Conditions where educators are unable to control the behaviour of learners undoubtedly leads to the degradation of teaching and learning, so the need to address the problem was real. The concluding chapter recommends strategies of dealing with challenging behaviour through classroom management, educator skills as well as disciplinary strategies. An environment that is conducive for teaching and learning will be created by such strategies.
- Full Text:
- Date Issued: 2014
Enabling cumulative knowledge-building through teaching: a legitimation code theory analysis of pedagogic practice in law and political science
- Authors: Clarence, Sherran
- Date: 2014
- Subjects: Law -- Study and teaching (Higher) -- South Africa Political science -- Study and teaching (Higher) -- South Africa Education, Higher -- South Africa College teaching -- South Africa Knowledge, Theory of Social realism
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1966 , http://hdl.handle.net/10962/d1011763
- Description: Much current research and practice in teaching and learning in higher education tends to overfocus on social aspects of education; on how rather than what students are learning. Much of this research and practice is influenced by constructivism, which has a relativist stance on knowledge, generally arguing, contra positivism, that knowledge is constructed in socio-historical contexts and largely inseparable from those who construct it and from issues of power. This leads to a confusion of knowledge with knowing, and knowledge is thus obscured as an object of study because it is only seen or understood as knowing or as a subject of learning and teaching. This ‘knowledge-blindness’ (Maton 2013a: 4) is problematic in higher education because knowledge and knowing are two separate parts of educational fields, and while they need to be brought together to provide a whole account of these fields, they also need to be analysed and understood separately to avoid blurring necessary boundaries and to avoid confusing knowledge itself with how it can be known. Being able to see and analyse knowledge as an object with its own properties and powers is crucial for both epistemological access and social inclusion and justice, because knowledge and knowledge practices are at the heart of academic disciplines in universities. Social realism offers an alternative to the dilemma brought about by constructivism’s tendency towards knowledge-blindness. Social realism argues that it is possible to see and analyse both actors within social fields of practice as well as knowledge as something that is produced by these actors but also about more than just these actors and their practices; thus knowledge can be understood as emergent from these practices and fields but not reducible to them (Maton & Moore 2010). Social realism, drawing from Roy Bhaskar’s critical realist philosophy (1975, 2008), is intent on looking at the real structures and mechanisms that lie beneath appearances and practices in order to understand the ways in which these practices are shaped, and change over time. Legitimation Code Theory is a realist conceptual framework that has, as its central aim, the uncovering and analysis of organising principles that shape and change intellectual and education fields of production and reproduction of knowledge. In other words, the conceptual tools Legitimation Code Theory offers can enable an analysis of both knowledge and knowers within relational social fields of practice by enabling the analysis of the ways in which these fields, such as academic disciplines, are organised and how knowledge and knowing are understood in educational practice. This study draws on social realism more broadly and Legitimation Code Theory specifically to develop a relatively novel conceptual and explanatory framework within which to analyse and answer its central question regarding how to enable cumulative knowledge building through pedagogic practice. Using qualitative data from two academic disciplines, Law and Political Science, which was analysed using a set of conceptual and analytical tools drawn from Legitimation Code Theory, this study shows that the more nuanced and layered accounts of pedagogy that have been generated are able to provide valuable insights into what lecturers are doing as they teach in terms of helping students to acquire, use and produce disciplinary and ‘powerful’ knowledge (Young 2008b). Further, the study demonstrates that the organising principles underlying academic disciplines have a profound effect on how the role of the knower and the place or purpose of knowledge is understood in pedagogy and this affects how the pedagogy is designed and enacted. This study has argued that if we can research pedagogy rigorously using tools that allow us to see the real mechanisms and principles influencing and shaping it, and if we can reclaim the role of disciplinary knowledge as a central part of the pedagogic relationship between lecturer and students, then we can begin to see how teaching both enables and constrains cumulative learning. Further, we can change pedagogy to better enable cumulative learning and greater epistemological access to disciplinary knowledge and related practices for greater numbers of students. The study concludes by suggesting that the conceptual tools offered by Legitimation Code Theory can provide academic lecturers with a set of tools that can begin to enable them to 'see' and understand their own teaching more clearly, as well as the possible gaps between what they are teaching and what their students are learning. This study argues that a social realist approach to the study of pedagogy such as the one used here can begin not only to enable changes in pedagogy aimed at filling these gaps but also begin to provide a more rigorous theoretical and practical approach to analysing, understanding and enacting pedagogic practice. This, in turn, can lead to more socially just and inclusive student learning and epistemic and social access to the powerful knowledge and ways of knowing in their disciplines.
- Full Text:
- Date Issued: 2014
- Authors: Clarence, Sherran
- Date: 2014
- Subjects: Law -- Study and teaching (Higher) -- South Africa Political science -- Study and teaching (Higher) -- South Africa Education, Higher -- South Africa College teaching -- South Africa Knowledge, Theory of Social realism
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1966 , http://hdl.handle.net/10962/d1011763
- Description: Much current research and practice in teaching and learning in higher education tends to overfocus on social aspects of education; on how rather than what students are learning. Much of this research and practice is influenced by constructivism, which has a relativist stance on knowledge, generally arguing, contra positivism, that knowledge is constructed in socio-historical contexts and largely inseparable from those who construct it and from issues of power. This leads to a confusion of knowledge with knowing, and knowledge is thus obscured as an object of study because it is only seen or understood as knowing or as a subject of learning and teaching. This ‘knowledge-blindness’ (Maton 2013a: 4) is problematic in higher education because knowledge and knowing are two separate parts of educational fields, and while they need to be brought together to provide a whole account of these fields, they also need to be analysed and understood separately to avoid blurring necessary boundaries and to avoid confusing knowledge itself with how it can be known. Being able to see and analyse knowledge as an object with its own properties and powers is crucial for both epistemological access and social inclusion and justice, because knowledge and knowledge practices are at the heart of academic disciplines in universities. Social realism offers an alternative to the dilemma brought about by constructivism’s tendency towards knowledge-blindness. Social realism argues that it is possible to see and analyse both actors within social fields of practice as well as knowledge as something that is produced by these actors but also about more than just these actors and their practices; thus knowledge can be understood as emergent from these practices and fields but not reducible to them (Maton & Moore 2010). Social realism, drawing from Roy Bhaskar’s critical realist philosophy (1975, 2008), is intent on looking at the real structures and mechanisms that lie beneath appearances and practices in order to understand the ways in which these practices are shaped, and change over time. Legitimation Code Theory is a realist conceptual framework that has, as its central aim, the uncovering and analysis of organising principles that shape and change intellectual and education fields of production and reproduction of knowledge. In other words, the conceptual tools Legitimation Code Theory offers can enable an analysis of both knowledge and knowers within relational social fields of practice by enabling the analysis of the ways in which these fields, such as academic disciplines, are organised and how knowledge and knowing are understood in educational practice. This study draws on social realism more broadly and Legitimation Code Theory specifically to develop a relatively novel conceptual and explanatory framework within which to analyse and answer its central question regarding how to enable cumulative knowledge building through pedagogic practice. Using qualitative data from two academic disciplines, Law and Political Science, which was analysed using a set of conceptual and analytical tools drawn from Legitimation Code Theory, this study shows that the more nuanced and layered accounts of pedagogy that have been generated are able to provide valuable insights into what lecturers are doing as they teach in terms of helping students to acquire, use and produce disciplinary and ‘powerful’ knowledge (Young 2008b). Further, the study demonstrates that the organising principles underlying academic disciplines have a profound effect on how the role of the knower and the place or purpose of knowledge is understood in pedagogy and this affects how the pedagogy is designed and enacted. This study has argued that if we can research pedagogy rigorously using tools that allow us to see the real mechanisms and principles influencing and shaping it, and if we can reclaim the role of disciplinary knowledge as a central part of the pedagogic relationship between lecturer and students, then we can begin to see how teaching both enables and constrains cumulative learning. Further, we can change pedagogy to better enable cumulative learning and greater epistemological access to disciplinary knowledge and related practices for greater numbers of students. The study concludes by suggesting that the conceptual tools offered by Legitimation Code Theory can provide academic lecturers with a set of tools that can begin to enable them to 'see' and understand their own teaching more clearly, as well as the possible gaps between what they are teaching and what their students are learning. This study argues that a social realist approach to the study of pedagogy such as the one used here can begin not only to enable changes in pedagogy aimed at filling these gaps but also begin to provide a more rigorous theoretical and practical approach to analysing, understanding and enacting pedagogic practice. This, in turn, can lead to more socially just and inclusive student learning and epistemic and social access to the powerful knowledge and ways of knowing in their disciplines.
- Full Text:
- Date Issued: 2014
Energy and sustainable development: the case of Dewedzo rural community in Zimbabwe
- Authors: Mbulayi, Shingirai P
- Date: 2014
- Subjects: Sustainable development -- Zimbabwe , Renewable energy sources -- Zimbabwe , Power resources -- Zimbabwe , Energy consumption -- Zimbabwe
- Language: English
- Type: Thesis , Masters , M Soc Sc (Dev)
- Identifier: http://hdl.handle.net/10353/866 , vital:26504 , Sustainable development -- Zimbabwe , Renewable energy sources -- Zimbabwe , Power resources -- Zimbabwe , Energy consumption -- Zimbabwe
- Description: Energy poverty is a concept that has gained significance quite recently. Its significance has been prompted by the realization that without sustainable modern energy alternatives for the rural poor, prospects for rural transformation remains low. The recognition of modern energy as one of the missing link in rural transformation comes amid the growing concern about the negative effects of relying on traditional energy services and the increasing forecasts that most developing countries are likely to miss their MDG targets by 2015. Drawing on the Modernization and the Sustainable Development Approach, this study concluded that improving the quantity and quality of energy services consumed by the rural poor can counteract rural underdevelopment and enhance rural social and economic transformation in Dewedzo. The study confirmed that energy poor households are prone to various social, economic and environmental detriments such as poor health, hunger, malnutrition, poor education and missed socio economic opportunities. By addressing rural people‟s energy needs, more nexus can be injected into rural productivity and the economic social outputs of this process can in turn increase the pace at which MDGs can be achieved.
- Full Text:
- Date Issued: 2014
- Authors: Mbulayi, Shingirai P
- Date: 2014
- Subjects: Sustainable development -- Zimbabwe , Renewable energy sources -- Zimbabwe , Power resources -- Zimbabwe , Energy consumption -- Zimbabwe
- Language: English
- Type: Thesis , Masters , M Soc Sc (Dev)
- Identifier: http://hdl.handle.net/10353/866 , vital:26504 , Sustainable development -- Zimbabwe , Renewable energy sources -- Zimbabwe , Power resources -- Zimbabwe , Energy consumption -- Zimbabwe
- Description: Energy poverty is a concept that has gained significance quite recently. Its significance has been prompted by the realization that without sustainable modern energy alternatives for the rural poor, prospects for rural transformation remains low. The recognition of modern energy as one of the missing link in rural transformation comes amid the growing concern about the negative effects of relying on traditional energy services and the increasing forecasts that most developing countries are likely to miss their MDG targets by 2015. Drawing on the Modernization and the Sustainable Development Approach, this study concluded that improving the quantity and quality of energy services consumed by the rural poor can counteract rural underdevelopment and enhance rural social and economic transformation in Dewedzo. The study confirmed that energy poor households are prone to various social, economic and environmental detriments such as poor health, hunger, malnutrition, poor education and missed socio economic opportunities. By addressing rural people‟s energy needs, more nexus can be injected into rural productivity and the economic social outputs of this process can in turn increase the pace at which MDGs can be achieved.
- Full Text:
- Date Issued: 2014
Enhanced nonlinear optical properties of octa-substituted lead and cadmium phthalocyanines when embedded in poly (bisphenol A carbonate) as thin films
- Mkhize, Colin, Britton, Jonathan, Nyokong, Tebello
- Authors: Mkhize, Colin , Britton, Jonathan , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241459 , vital:50941 , xlink:href="https://doi.org/10.1016/j.poly.2014.07.025"
- Description: This work presents photophysical and nonlinear optical properties of a novel Cd 2,3-[octakis{4-tert-butylphenoxyphthalocyanine}] (CdOtBPPc) and compare them with those of Pb 2,3-[octakis{4-tert-butylphenoxyphthalocyanine}] (PbOtBPPc). For both the CdOtBPPc and PbOtBPPc, third order imaginary susceptibility and second order hyperpolarizability values were found to be within the limit set for good optical limiters. The Pcs were embedded in poly (methyl methacrylate) (PMMA) and poly(bisphenol A carbonate) (PBC) as thin films. The optical limiting values of the Pcs once embedded in film were found to be greatly improved and the limiting fluence of each film was well below the maximum threshold. Both PbOtBPPc and CdOtBPPc showed better optical limiting when embedded in PBC compared to PMMA. CdOtBPPc shows better nonlinear optical behavior than PbOtBPPc in solution and as thin films, even though the former is aggregated in solution.
- Full Text:
- Date Issued: 2014
- Authors: Mkhize, Colin , Britton, Jonathan , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241459 , vital:50941 , xlink:href="https://doi.org/10.1016/j.poly.2014.07.025"
- Description: This work presents photophysical and nonlinear optical properties of a novel Cd 2,3-[octakis{4-tert-butylphenoxyphthalocyanine}] (CdOtBPPc) and compare them with those of Pb 2,3-[octakis{4-tert-butylphenoxyphthalocyanine}] (PbOtBPPc). For both the CdOtBPPc and PbOtBPPc, third order imaginary susceptibility and second order hyperpolarizability values were found to be within the limit set for good optical limiters. The Pcs were embedded in poly (methyl methacrylate) (PMMA) and poly(bisphenol A carbonate) (PBC) as thin films. The optical limiting values of the Pcs once embedded in film were found to be greatly improved and the limiting fluence of each film was well below the maximum threshold. Both PbOtBPPc and CdOtBPPc showed better optical limiting when embedded in PBC compared to PMMA. CdOtBPPc shows better nonlinear optical behavior than PbOtBPPc in solution and as thin films, even though the former is aggregated in solution.
- Full Text:
- Date Issued: 2014
Enhanced Optical Limiting Behavior of an Indium Phthalocyanine–Single-Walled Carbon Nanotube Composite
- Sanusi, Kayode, Amuhaya, Edith K, Nyokong, Tebello
- Authors: Sanusi, Kayode , Amuhaya, Edith K , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193871 , vital:45401 , xlink:href="https://doi.org/10.1021/jp501469e "
- Description: The nonlinear optical behavior of 2(3),9(10),16(17),23(24)-tetrakis-(4-aminophenoxy) phthalocyaninato indium (III) chloride (2) and its carbon nanotube composite in dimethylsulfoxide (DMSO) and dimethylformamide (DMF) solutions is described. The nonlinear third-order susceptibility and second-order hyperpolarizability values are also reported. A large nonlinear absorption that increased on covalent linking with single-walled carbon nanotubes (SWCNTs) was observed for the compound in DMSO. The nanosecond nonlinear absorption and the optical limiting behavior of this complex are shown to be dominated by a strong excited state absorption from a two-photon pumped state. The optical limiter using the new nanocomposite material (SWCNT-2) in the appropriate solvent showed a much lower threshold for optical limiting together with a much lower transmission at high fluences than previously reported nanocomposite limiters. The optical properties of the phthalocyanine and its conjugate were found to show high sensitivity toward the change of solvent matrix.
- Full Text:
- Date Issued: 2014
- Authors: Sanusi, Kayode , Amuhaya, Edith K , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193871 , vital:45401 , xlink:href="https://doi.org/10.1021/jp501469e "
- Description: The nonlinear optical behavior of 2(3),9(10),16(17),23(24)-tetrakis-(4-aminophenoxy) phthalocyaninato indium (III) chloride (2) and its carbon nanotube composite in dimethylsulfoxide (DMSO) and dimethylformamide (DMF) solutions is described. The nonlinear third-order susceptibility and second-order hyperpolarizability values are also reported. A large nonlinear absorption that increased on covalent linking with single-walled carbon nanotubes (SWCNTs) was observed for the compound in DMSO. The nanosecond nonlinear absorption and the optical limiting behavior of this complex are shown to be dominated by a strong excited state absorption from a two-photon pumped state. The optical limiter using the new nanocomposite material (SWCNT-2) in the appropriate solvent showed a much lower threshold for optical limiting together with a much lower transmission at high fluences than previously reported nanocomposite limiters. The optical properties of the phthalocyanine and its conjugate were found to show high sensitivity toward the change of solvent matrix.
- Full Text:
- Date Issued: 2014
Enhanced optical limiting performance in phthalocyanine-quantum dot nanocomposites by free-carrier absorption mechanism
- Sanusi, Kayode, Khene, Samson M, Nyokong, Tebello
- Authors: Sanusi, Kayode , Khene, Samson M , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193904 , vital:45404 , xlink:href="https://doi.org/10.1016/j.optmat.2014.07.024"
- Description: Enhanced nonlinear optical properties (in dimethyl sulphoxide) is observed for 2(3),9(10),16(17),23(24)-tetrakis-(4-aminophenoxy)phthalocyaninato indium(III) chloride (InPc) when covalently linked to CdSe/ZnS or CdSe quantum dots (QDs). The experimental nonlinear optical parameters were obtained from Z-Scan measurements. Contributions from two-photon absorption (2PA) due to the InPc, and free-carrier absorption (FCA) by QDS have been identified as the main factors responsible for the enhanced optical limiting. The effective nonlinear absorption coefficient for InPc-CdSe/ZnS was found to be 700.0 cm/GW. The FCA cross-sections for InPc-CdSe/ZnS and InPc-CdSe composites were found to be 1.52 × 10−19 and 6.00 × 10−20 cm2 respectively. A much lower limiting threshold of 92 mJ cm−2 was observed for InPc-CdSe/ZnS nanocomposite, hence, making it suitable for use as optical limiting material. Density Functional Theory (DFT) calculations on similar phthalocyanine-quantum dots system was modeled in order to explain the enhancement in the observed nonlinear optical properties of the Pc in the presence of the QDs. The experimentally determined nonlinear optical properties are well within the range of the DFT calculated properties.
- Full Text:
- Date Issued: 2014
- Authors: Sanusi, Kayode , Khene, Samson M , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193904 , vital:45404 , xlink:href="https://doi.org/10.1016/j.optmat.2014.07.024"
- Description: Enhanced nonlinear optical properties (in dimethyl sulphoxide) is observed for 2(3),9(10),16(17),23(24)-tetrakis-(4-aminophenoxy)phthalocyaninato indium(III) chloride (InPc) when covalently linked to CdSe/ZnS or CdSe quantum dots (QDs). The experimental nonlinear optical parameters were obtained from Z-Scan measurements. Contributions from two-photon absorption (2PA) due to the InPc, and free-carrier absorption (FCA) by QDS have been identified as the main factors responsible for the enhanced optical limiting. The effective nonlinear absorption coefficient for InPc-CdSe/ZnS was found to be 700.0 cm/GW. The FCA cross-sections for InPc-CdSe/ZnS and InPc-CdSe composites were found to be 1.52 × 10−19 and 6.00 × 10−20 cm2 respectively. A much lower limiting threshold of 92 mJ cm−2 was observed for InPc-CdSe/ZnS nanocomposite, hence, making it suitable for use as optical limiting material. Density Functional Theory (DFT) calculations on similar phthalocyanine-quantum dots system was modeled in order to explain the enhancement in the observed nonlinear optical properties of the Pc in the presence of the QDs. The experimentally determined nonlinear optical properties are well within the range of the DFT calculated properties.
- Full Text:
- Date Issued: 2014
Enhanced visualisation techniques to support access to personal information across multiple devices
- Authors: Beets, Simone Yvonne
- Date: 2014
- Subjects: Information visualisation , Database management , Web services , Personal information management
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10500 , http://hdl.handle.net/10948/d1021136
- Description: The increasing number of devices owned by a single user makes it increasingly difficult to access, organise and visualise personal information (PI), i.e. documents and media, across these devices. The primary method that is currently used to organise and visualise PI is the hierarchical folder structure, which is a familiar and widely used means to manage PI. However, this hierarchy does not effectively support personal information management (PIM) across multiple devices. Current solutions, such as the Personal Information Dashboard and Stuff I’ve Seen, do not support PIM across multiple devices. Alternative PIM tools, such as Dropbox and TeamViewer, attempt to provide a means of accessing PI across multiple devices, but these solutions also suffer from several limitations. The aim of this research was to investigate to what extent enhanced information visualisation (IV) techniques could be used to support accessing PI across multiple devices. An interview study was conducted to identify how PI is currently managed across multiple devices. This interview study further motivated the need for a tool to support visualising PI across multiple devices and identified requirements for such an IV tool. Several suitable IV techniques were selected and enhanced to support PIM across multiple devices. These techniques comprised an Overview using a nested circles layout, a Tag Cloud and a Partition Layout, which used a novel set-based technique. A prototype, called MyPSI, was designed and implemented incorporating these enhanced IV techniques. The requirements and design of the MyPSI prototype were validated using a conceptual walkthrough. The design of the MyPSI prototype was initially implemented for a desktop or laptop device with mouse-based interaction. A sample personal space of information (PSI) was used to evaluate the prototype in a controlled user study. The user study was used to identify any usability problems with the MyPSI prototype. The results were highly positive and the participants agreed that such a tool could be useful in future. No major problems were identified with the prototype. The MyPSI prototype was then implemented on a mobile device, specifically an Android tablet device, using a similar design, but supporting touch-based interaction. Users were allowed to upload their own PSI using Dropbox, which was visualised by the MyPSI prototype. A field study was conducted following the Multi-dimensional In-depth Long-term Case Studies approach specifically designed for IV evaluation. The field study was conducted over a two-week period, evaluating both the desktop and mobile versions of the MyPSI prototype. Both versions received positive results, but the desktop version was slightly preferred over the mobile version, mainly due to familiarity and problems experienced with the mobile implementation. Design recommendations were derived to inform future designs of IV tools to support accessing PI across multiple devices. This research has shown that IV techniques can be enhanced to effectively support accessing PI across multiple devices. Future work will involve customising the MyPSI prototype for mobile phones and supporting additional platforms.
- Full Text:
- Date Issued: 2014
- Authors: Beets, Simone Yvonne
- Date: 2014
- Subjects: Information visualisation , Database management , Web services , Personal information management
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10500 , http://hdl.handle.net/10948/d1021136
- Description: The increasing number of devices owned by a single user makes it increasingly difficult to access, organise and visualise personal information (PI), i.e. documents and media, across these devices. The primary method that is currently used to organise and visualise PI is the hierarchical folder structure, which is a familiar and widely used means to manage PI. However, this hierarchy does not effectively support personal information management (PIM) across multiple devices. Current solutions, such as the Personal Information Dashboard and Stuff I’ve Seen, do not support PIM across multiple devices. Alternative PIM tools, such as Dropbox and TeamViewer, attempt to provide a means of accessing PI across multiple devices, but these solutions also suffer from several limitations. The aim of this research was to investigate to what extent enhanced information visualisation (IV) techniques could be used to support accessing PI across multiple devices. An interview study was conducted to identify how PI is currently managed across multiple devices. This interview study further motivated the need for a tool to support visualising PI across multiple devices and identified requirements for such an IV tool. Several suitable IV techniques were selected and enhanced to support PIM across multiple devices. These techniques comprised an Overview using a nested circles layout, a Tag Cloud and a Partition Layout, which used a novel set-based technique. A prototype, called MyPSI, was designed and implemented incorporating these enhanced IV techniques. The requirements and design of the MyPSI prototype were validated using a conceptual walkthrough. The design of the MyPSI prototype was initially implemented for a desktop or laptop device with mouse-based interaction. A sample personal space of information (PSI) was used to evaluate the prototype in a controlled user study. The user study was used to identify any usability problems with the MyPSI prototype. The results were highly positive and the participants agreed that such a tool could be useful in future. No major problems were identified with the prototype. The MyPSI prototype was then implemented on a mobile device, specifically an Android tablet device, using a similar design, but supporting touch-based interaction. Users were allowed to upload their own PSI using Dropbox, which was visualised by the MyPSI prototype. A field study was conducted following the Multi-dimensional In-depth Long-term Case Studies approach specifically designed for IV evaluation. The field study was conducted over a two-week period, evaluating both the desktop and mobile versions of the MyPSI prototype. Both versions received positive results, but the desktop version was slightly preferred over the mobile version, mainly due to familiarity and problems experienced with the mobile implementation. Design recommendations were derived to inform future designs of IV tools to support accessing PI across multiple devices. This research has shown that IV techniques can be enhanced to effectively support accessing PI across multiple devices. Future work will involve customising the MyPSI prototype for mobile phones and supporting additional platforms.
- Full Text:
- Date Issued: 2014
Enhancement of the usability of SOA services for novice users
- Authors: Yalezo, Sabelo
- Date: 2014
- Language: English
- Type: Thesis , Masters , MSc (Computer Science)
- Identifier: http://hdl.handle.net/10353/822 , vital:26500
- Description: Recently, the automation of service integration has provided a significant advantage in delivering services to novice users. This art of integrating various services is known as Service Composition and its main purpose is to simplify the development process for web applications and facilitates reuse of services. It is one of the paradigms that enables services to end-users (i.e.service provisioning) through the outsourcing of web contents and it requires users to share and reuse services in more collaborative ways. Most service composers are effective at enabling integration of web contents, but they do not enable universal access across different groups of users. This is because, the currently existing content aggregators require complex interactions in order to create web applications (e.g., Web Service Business Process Execution Language (WS-BPEL)) as a result not all users are able to use such web tools. This trend demands changes in the web tools that end-users use to gain and share information, hence this research uses Mashups as a service composition technique to allow novice users to integrate publicly available Service Oriented Architecture (SOA) services, where there is a minimal active web application development. Mashups being the platforms that integrate disparate web Application Programming Interfaces (APIs) to create user defined web applications; presents a great opportunity for service provisioning. However, their usability for novice users remains invalidated since Mashup tools are not easy to use they require basic programming skills which makes the process of designing and creating Mashups difficult. This is because Mashup tools access heterogeneous web contents using public web APIs and the process of integrating them become complex since web APIs are tailored by different vendors. Moreover, the design of Mashup editors is unnecessary complex; as a result, users do not know where to start when creating Mashups. This research address the gap between Mashup tools and usability by the designing and implementing a semantically enriched Mashup tool to discover, annotate and compose APIs to improve the utilization of SOA services by novice users. The researchers conducted an analysis of the already existing Mashup tools to identify challenges and weaknesses experienced by novice Mashup users. The findings from the requirement analysis formulated the system usability requirements that informed the design and implementation of the proposed Mashup tool. The proposed architecture addressed three layers: composition, annotation and discovery. The researchers developed a simple Mashup tool referred to as soa-Services Provisioner (SerPro) that allowed novice users to create web application flexibly. Its usability and effectiveness was validated. The proposed Mashup tool enhanced the usability of SOA services, since data analysis and results showed that it was usable to novice users by scoring a System Usability Scale (SUS) score of 72.08. Furthermore, this research discusses the research limitations and future work for further improvements.
- Full Text:
- Date Issued: 2014
- Authors: Yalezo, Sabelo
- Date: 2014
- Language: English
- Type: Thesis , Masters , MSc (Computer Science)
- Identifier: http://hdl.handle.net/10353/822 , vital:26500
- Description: Recently, the automation of service integration has provided a significant advantage in delivering services to novice users. This art of integrating various services is known as Service Composition and its main purpose is to simplify the development process for web applications and facilitates reuse of services. It is one of the paradigms that enables services to end-users (i.e.service provisioning) through the outsourcing of web contents and it requires users to share and reuse services in more collaborative ways. Most service composers are effective at enabling integration of web contents, but they do not enable universal access across different groups of users. This is because, the currently existing content aggregators require complex interactions in order to create web applications (e.g., Web Service Business Process Execution Language (WS-BPEL)) as a result not all users are able to use such web tools. This trend demands changes in the web tools that end-users use to gain and share information, hence this research uses Mashups as a service composition technique to allow novice users to integrate publicly available Service Oriented Architecture (SOA) services, where there is a minimal active web application development. Mashups being the platforms that integrate disparate web Application Programming Interfaces (APIs) to create user defined web applications; presents a great opportunity for service provisioning. However, their usability for novice users remains invalidated since Mashup tools are not easy to use they require basic programming skills which makes the process of designing and creating Mashups difficult. This is because Mashup tools access heterogeneous web contents using public web APIs and the process of integrating them become complex since web APIs are tailored by different vendors. Moreover, the design of Mashup editors is unnecessary complex; as a result, users do not know where to start when creating Mashups. This research address the gap between Mashup tools and usability by the designing and implementing a semantically enriched Mashup tool to discover, annotate and compose APIs to improve the utilization of SOA services by novice users. The researchers conducted an analysis of the already existing Mashup tools to identify challenges and weaknesses experienced by novice Mashup users. The findings from the requirement analysis formulated the system usability requirements that informed the design and implementation of the proposed Mashup tool. The proposed architecture addressed three layers: composition, annotation and discovery. The researchers developed a simple Mashup tool referred to as soa-Services Provisioner (SerPro) that allowed novice users to create web application flexibly. Its usability and effectiveness was validated. The proposed Mashup tool enhanced the usability of SOA services, since data analysis and results showed that it was usable to novice users by scoring a System Usability Scale (SUS) score of 72.08. Furthermore, this research discusses the research limitations and future work for further improvements.
- Full Text:
- Date Issued: 2014