Removal rate of endocrine disruptors (phthalates and phenolic compounds) in effluents of selected wastewater treatment plants operated under different treatment technologies in the Eastern Cape, South Africa
- Authors: Salaudeen, Taofeek Gbenga
- Date: 2017
- Subjects: Water -- Purification Phenols
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/8552 , vital:33113
- Description: The presence of phthalate esters (PAEs) and certain phenolic compounds widely known as endocrine disruptors in environmental waters such as treated wastewaters constitutes health hazard to human and aquatic lives. Unfortunately, wastewater treatment plants (WWTPs) only partially remove these synthetic chemical compounds from wastewater. In order to forestall the health challenge faced by rural dwellers, which rely on surface water for their daily needs, the present study embarked on investigating these endocrine disruptors in Municipal wastewater in the Amathole and Buffalo Districts in the Eastern Cape, South Africa and their removal rate by different WWTP technologies. One WWTP each from Adelaide, Alice, Bedford, Berlin and Seymour, using activated sludge (AS), trickling filter (TF), and oxidation pond (OP) technology were randomly selected. Some physicochemical parameters of these wastewaters were determined on-site using standard methods and the extraction method for endocrine disrupting chemicals (EDCs) in water was validated using solid phase extraction (SPE). Extracts were analysed using gas chromatography-mass spectrometer (GC-MS). Nine phenolic compounds; phenol (PH), 2-chlorophenol (2-CP), 2,4-dimethylphenol (2,4-DMP), 2,4-dichlorophenol (2,4-DCP), 4-chloro-3-methylphenol (4-C-3MP), 2-nitrophenol (2-NP), 4-nitrophenol (4-NP), pentachlorophenol (PCP), 2,4,6-trichlorophenol (2,4,6-TCP) and six priority PAEs namely; dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), benzyl butyl phthalate (BBP), di(2-ethyl hexyl) phthalate (DEHP), and di-n-octyl phthalate (DOP) were the investigated EDCs. PAEs were extracted from dried sludge samples in an ultrasonic bath using dichloromethane. Some physicochemical parameters of the wastewater assessed revealed that treatment processes of AS, TF, and OP reduced turbidity, total suspended solids (TSS), total dissolved solids (TDS), and electrical conductivity (EC) while dissolved oxygen (DO) was increased. There was no significant influence on temperature and pH across the sampling points. Except for turbidity, the quality of effluent released mostly falls within South Africa standard limits for domestic and recreational water. The nine phenolic compounds were detected across the sampling points for all the WWTPs at different frequencies. The prominent phenolic compounds were 2-NP, 4-C-3MP, PCP, and 2,4-DMP with concentrations ranging from 3.3 (2,4-DMP) – 83.0 μgL-1 (4-C-3MP) in the influents. However, their concentrations in the effluents and receiving water bodies were below tolerable limits of 5 μgL-1 set by the US Environmental Protection Agency (USEPA) and the European Union (EU) for domestic use. The removal capacities of the WWTPs varied between 33 and 96 percent. The six PAEs were detected in all water samples from all the WWTPs. DBP was the most abundant compound in all the sampling points and sometimes DEHP in some receiving waters. The maximum detection for DBP in influent, effluent, downstream and sludge were 2,488 μgL-1 (Alice), 26.47 μgL-1 (Adelaide), 115.3 μgL-1 (Seymour) and 1,249 μg/g dw (Alice), respectively. DEHP was the highest detected PAE in the upstream 17.53 μgL-1 (Seymour). There was a notable reduction of all PAEs in the final effluent with a removal efficiency which varied as much as 61.9 – 99.5 percent except for AS in Seymour which operated a single tank system (27.3 - 93.7 percent). Removal mechanisms continued more on adsorption on settling particles and sludge than biodegradation as this study found a high positive correlation between TSS, turbidity and PAEs removal. The concentrations of PAEs detected in the receiving waters were above 1.3 and 3μgL-1 limit standard set by the EU and USEPA, respectively for DEHP in surface water. Similarly, the average concentrations of DBP, BBP, DEHP and DOP which vary as much as 25.97 (BBP) – 1249 μg/g d.w (DBP) in sludge samples were above EU legislation of 100 μg/g d.w. for agricultural use. AS technology, showed a better performance in the removal of PAEs (77 – 99 percent), followed by TF (76 – 98 percent) and OP (61 – 98 percent). In conclusion, the PAE concentration in the WWTP effluents impacted negatively on the receiving water bodies and sewage sludge unlike the phenolic compounds that were notably reduced below the acceptable limits. Perhaps, due to the meagre amounts of the phenolic compounds that was detected entering the WWTPs. In order to avert the potential health risk to aquatic organisms’ and rural dwellers, it is exigent that constituted authorities gather more information on micro-pollutants in the environment as a basis for regulations on the use of these dangerous chemicals in industries.
- Full Text:
- Authors: Salaudeen, Taofeek Gbenga
- Date: 2017
- Subjects: Water -- Purification Phenols
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/8552 , vital:33113
- Description: The presence of phthalate esters (PAEs) and certain phenolic compounds widely known as endocrine disruptors in environmental waters such as treated wastewaters constitutes health hazard to human and aquatic lives. Unfortunately, wastewater treatment plants (WWTPs) only partially remove these synthetic chemical compounds from wastewater. In order to forestall the health challenge faced by rural dwellers, which rely on surface water for their daily needs, the present study embarked on investigating these endocrine disruptors in Municipal wastewater in the Amathole and Buffalo Districts in the Eastern Cape, South Africa and their removal rate by different WWTP technologies. One WWTP each from Adelaide, Alice, Bedford, Berlin and Seymour, using activated sludge (AS), trickling filter (TF), and oxidation pond (OP) technology were randomly selected. Some physicochemical parameters of these wastewaters were determined on-site using standard methods and the extraction method for endocrine disrupting chemicals (EDCs) in water was validated using solid phase extraction (SPE). Extracts were analysed using gas chromatography-mass spectrometer (GC-MS). Nine phenolic compounds; phenol (PH), 2-chlorophenol (2-CP), 2,4-dimethylphenol (2,4-DMP), 2,4-dichlorophenol (2,4-DCP), 4-chloro-3-methylphenol (4-C-3MP), 2-nitrophenol (2-NP), 4-nitrophenol (4-NP), pentachlorophenol (PCP), 2,4,6-trichlorophenol (2,4,6-TCP) and six priority PAEs namely; dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), benzyl butyl phthalate (BBP), di(2-ethyl hexyl) phthalate (DEHP), and di-n-octyl phthalate (DOP) were the investigated EDCs. PAEs were extracted from dried sludge samples in an ultrasonic bath using dichloromethane. Some physicochemical parameters of the wastewater assessed revealed that treatment processes of AS, TF, and OP reduced turbidity, total suspended solids (TSS), total dissolved solids (TDS), and electrical conductivity (EC) while dissolved oxygen (DO) was increased. There was no significant influence on temperature and pH across the sampling points. Except for turbidity, the quality of effluent released mostly falls within South Africa standard limits for domestic and recreational water. The nine phenolic compounds were detected across the sampling points for all the WWTPs at different frequencies. The prominent phenolic compounds were 2-NP, 4-C-3MP, PCP, and 2,4-DMP with concentrations ranging from 3.3 (2,4-DMP) – 83.0 μgL-1 (4-C-3MP) in the influents. However, their concentrations in the effluents and receiving water bodies were below tolerable limits of 5 μgL-1 set by the US Environmental Protection Agency (USEPA) and the European Union (EU) for domestic use. The removal capacities of the WWTPs varied between 33 and 96 percent. The six PAEs were detected in all water samples from all the WWTPs. DBP was the most abundant compound in all the sampling points and sometimes DEHP in some receiving waters. The maximum detection for DBP in influent, effluent, downstream and sludge were 2,488 μgL-1 (Alice), 26.47 μgL-1 (Adelaide), 115.3 μgL-1 (Seymour) and 1,249 μg/g dw (Alice), respectively. DEHP was the highest detected PAE in the upstream 17.53 μgL-1 (Seymour). There was a notable reduction of all PAEs in the final effluent with a removal efficiency which varied as much as 61.9 – 99.5 percent except for AS in Seymour which operated a single tank system (27.3 - 93.7 percent). Removal mechanisms continued more on adsorption on settling particles and sludge than biodegradation as this study found a high positive correlation between TSS, turbidity and PAEs removal. The concentrations of PAEs detected in the receiving waters were above 1.3 and 3μgL-1 limit standard set by the EU and USEPA, respectively for DEHP in surface water. Similarly, the average concentrations of DBP, BBP, DEHP and DOP which vary as much as 25.97 (BBP) – 1249 μg/g d.w (DBP) in sludge samples were above EU legislation of 100 μg/g d.w. for agricultural use. AS technology, showed a better performance in the removal of PAEs (77 – 99 percent), followed by TF (76 – 98 percent) and OP (61 – 98 percent). In conclusion, the PAE concentration in the WWTP effluents impacted negatively on the receiving water bodies and sewage sludge unlike the phenolic compounds that were notably reduced below the acceptable limits. Perhaps, due to the meagre amounts of the phenolic compounds that was detected entering the WWTPs. In order to avert the potential health risk to aquatic organisms’ and rural dwellers, it is exigent that constituted authorities gather more information on micro-pollutants in the environment as a basis for regulations on the use of these dangerous chemicals in industries.
- Full Text:
Richard Charles Nicholas Branson : a psychobiographical study
- Authors: Preston, Amanda Lorraine
- Date: 2017
- Subjects: Branson, Richard Charles Nicholas, -- 1950- Businessmen -- Great Britain -- Biography Success in business
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/5543 , vital:29318
- Description: Unique individuals are fascinating as we all want to be successful. There is thus a need to understand, unpack and share the psychological development and traits that allow some people to become sui generis, and to learn from them. Psychobiographical research is a qualitative approach that can be utilised to uncover the story of such an individual life, resulting in greater understanding of the psychological concepts underpinning the person. This form of study is invaluable, and involves applying psychological theory to lives completed or unfinished, enabling the development and testing of developmental theories. Richard Branson (1950-present), an entrepreneur, adventurer, philanthropist and family man is the single psychological subject chosen in this study. Branson was selected based on interest value, his uniqueness and the lack of a specifically academic and psychologically focused case study on his life. The primary aim was to explore and describe Branson’s personality development across his life, to date. This was achieved by applying both Maslow’s (1954, 1970) theory of optimal development and Adler’s (1929, 1956) Individual Psychology theory to provide a comprehensive idiographic interpretation of the development of Branson. To achieve this, the case study utilised the systematic and consistent collection, analysis and interpretation of life history materials, highlighting three areas of development, namely Childhood, Adolescence and Adulthood. The theoretical frameworks were used to discern, transform and reconstruct his life into a coherent and illuminating narrative of his psychological movement through life. Alexander’s (1988; 1990) model of identifying salient themes was used to analyse data for analytical generalisation (Yin, 2009). The conceptual framework derived from the theoretical perspective was constructed to organize, integrate data, and guide the presentation and discussion of findings of the study in an integrative and comprehensive manner. The findings suggest both Maslow’s and Adler’s theories considered the biopsychosocial context in Branson’s personality development and, at least to some extent, supported concepts indicative of progression toward optimality through having met the needs of the ego actualisation of his self, toward transcending selfishness and attaining altruism and social interest. The study of Branson’s personality development has provided a positive demonstration of the value of Maslow’s (1970a) and Adler’s (1929, 1956) theories to understand the process of development. It has further highlighted the unique trajectory of an individual’s life, contextualized, as well as the possibility of being agents in our own lives and despite challenges, able to become our own idiosyncratic best. The study also highlights the need, at a macro level, for governments to assist those unable to satisfy basic needs such as food, shelter and safety, to set an imperative, to aid those who struggle if a country and its people are to be uplifted. In terms of Adlerian theory, the study highlights the importance of family and early experiences in supporting the earliest years of children to assist them to develop an identity that is healthy and socially useful. Finally, recommendations were made for future research utilising a psychobiographical research design to uncover, illuminate and reconstruct the lives of outstanding and interesting individuals.
- Full Text:
- Authors: Preston, Amanda Lorraine
- Date: 2017
- Subjects: Branson, Richard Charles Nicholas, -- 1950- Businessmen -- Great Britain -- Biography Success in business
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/5543 , vital:29318
- Description: Unique individuals are fascinating as we all want to be successful. There is thus a need to understand, unpack and share the psychological development and traits that allow some people to become sui generis, and to learn from them. Psychobiographical research is a qualitative approach that can be utilised to uncover the story of such an individual life, resulting in greater understanding of the psychological concepts underpinning the person. This form of study is invaluable, and involves applying psychological theory to lives completed or unfinished, enabling the development and testing of developmental theories. Richard Branson (1950-present), an entrepreneur, adventurer, philanthropist and family man is the single psychological subject chosen in this study. Branson was selected based on interest value, his uniqueness and the lack of a specifically academic and psychologically focused case study on his life. The primary aim was to explore and describe Branson’s personality development across his life, to date. This was achieved by applying both Maslow’s (1954, 1970) theory of optimal development and Adler’s (1929, 1956) Individual Psychology theory to provide a comprehensive idiographic interpretation of the development of Branson. To achieve this, the case study utilised the systematic and consistent collection, analysis and interpretation of life history materials, highlighting three areas of development, namely Childhood, Adolescence and Adulthood. The theoretical frameworks were used to discern, transform and reconstruct his life into a coherent and illuminating narrative of his psychological movement through life. Alexander’s (1988; 1990) model of identifying salient themes was used to analyse data for analytical generalisation (Yin, 2009). The conceptual framework derived from the theoretical perspective was constructed to organize, integrate data, and guide the presentation and discussion of findings of the study in an integrative and comprehensive manner. The findings suggest both Maslow’s and Adler’s theories considered the biopsychosocial context in Branson’s personality development and, at least to some extent, supported concepts indicative of progression toward optimality through having met the needs of the ego actualisation of his self, toward transcending selfishness and attaining altruism and social interest. The study of Branson’s personality development has provided a positive demonstration of the value of Maslow’s (1970a) and Adler’s (1929, 1956) theories to understand the process of development. It has further highlighted the unique trajectory of an individual’s life, contextualized, as well as the possibility of being agents in our own lives and despite challenges, able to become our own idiosyncratic best. The study also highlights the need, at a macro level, for governments to assist those unable to satisfy basic needs such as food, shelter and safety, to set an imperative, to aid those who struggle if a country and its people are to be uplifted. In terms of Adlerian theory, the study highlights the importance of family and early experiences in supporting the earliest years of children to assist them to develop an identity that is healthy and socially useful. Finally, recommendations were made for future research utilising a psychobiographical research design to uncover, illuminate and reconstruct the lives of outstanding and interesting individuals.
- Full Text:
Rights as trumps in African communitarian ethics
- Authors: Nwogbo, Johnbosco
- Date: 2017
- Subjects: Communitarianism Human rights Social values
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10353/12282 , vital:39249
- Description: The notion of rights is among the most basic ideas of contemporary political philosophy on the continent and elsewhere. Although rights are common-place in political philosophy it is fair to say that the discussion around it has been nothing short of contested. On the whole, there have been two kinds of questions to which most of the discussion about rights in political philosophy have been answers, namely, (i) what are rights?, and (ii) to what do people have rights? The first has to do with the nature of rights, while the second has to the nature of that to which people may be said to have rights. This research falls neatly within the parlance of the first kind of questions (i.e., the question of what rights are). Specifically, in this research, I am concerned with the question of whether the radical and moderate African communitarian rights theses of Ifeanyi Menkiti and Kwame Gyekye measure up to what rights are commonly understood to be. I argue that if rights are trumps, which override competing societal and communal considerations, then Menkiti’s and Gyekye’s theories of rights fall short of this fairly standard and typical conception of rights.
- Full Text:
- Authors: Nwogbo, Johnbosco
- Date: 2017
- Subjects: Communitarianism Human rights Social values
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10353/12282 , vital:39249
- Description: The notion of rights is among the most basic ideas of contemporary political philosophy on the continent and elsewhere. Although rights are common-place in political philosophy it is fair to say that the discussion around it has been nothing short of contested. On the whole, there have been two kinds of questions to which most of the discussion about rights in political philosophy have been answers, namely, (i) what are rights?, and (ii) to what do people have rights? The first has to do with the nature of rights, while the second has to the nature of that to which people may be said to have rights. This research falls neatly within the parlance of the first kind of questions (i.e., the question of what rights are). Specifically, in this research, I am concerned with the question of whether the radical and moderate African communitarian rights theses of Ifeanyi Menkiti and Kwame Gyekye measure up to what rights are commonly understood to be. I argue that if rights are trumps, which override competing societal and communal considerations, then Menkiti’s and Gyekye’s theories of rights fall short of this fairly standard and typical conception of rights.
- Full Text:
Ruthenium sulphide nanoparticles derived from tri-dithiocarbamato ruthenium (III) complexes : synthesis, optical and structural studies
- Authors: Mbese, Johannes Zanoxolo
- Date: 2017
- Subjects: Nanoparticles Ruthenium compounds
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/15420 , vital:40406
- Description: The present Thesis pioneer the application of single-source molecular precursor method for the synthesis of ruthenium sulfide nanoparticles using a series of novel self-prepared single-source molecular precursors. The preparation of precursors involved the design and synthesis of compounds containing all the desired elements required within the coordination compound. Good precursors are tailored to give reproducible, clean decomposition at moderate temperatures, leading to high quality, defect free, mono-dispersed nanoparticles. Nine (9) homonuclear tris-dithiocarbamato ruthenium(III) complexes, [Ru(S2CNR2)3] were prepared from a stoichiometric reaction of RuCl3·H2O with self-prepared dithiocarbamate ligands at room temperature in a molar ratio of Ru3+: Ligand of 1:3. Dithiocarbamate ligands were derived from a stoichiometric reaction of carbon disulfide with (aniline, N-allylmethylamine, p-toluidine, p-anisidine, N-ethyl-m-toluidine, piperidine, morpholine, di-isopropylamine, and diallylamine) in the presence of concentrated ammonia or potassium hydroxide in ice cold bath. The dithiocarbamate ligands and complexes were characterized by elemental analyses, UV-Vis, Fourier transform infrared spectroscopy (FTIR), 1H- and 13C-NMR spectroscopy. Thermogravimetric analyses (TGA) was used to study the decomposition profiles of the precursor complexes. The results obtained from the TGA of precursors showed that the complexes decompose to ruthenium sulfide nanoparticles. The FTIR spectra of the ligands revealed prominent strong absorption bands ascribed to v(N-H) stretching vibrations and also confirm the bidentate coordination of the dithiocarbamate ligands. Ruthenium(III) complexes show absorption spectra in the visible region that exhibit bands attributed to n → π* electronic transitions located on the sulfur atoms located in the S–C–S and N–C–S chromophores of the bidentate dithiocarbamate ligands respectively. The absorption spectra also confirmed the geometry of ruthenium(III) complexes to be octahedral. The proposed structures of dithiocarbamate ligands and ruthenium(III) complexes were confirmed by the 1H- and 13C-NMR. The complexes were used as single-source molecular precursors for the synthesis of ruthenium sulfide nanoparticles. The structural and optical properties were studied using transmission electron microscope (TEM), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), UV-Vis absorption and photoluminescence (PL) spectra. FTIR revealed that Ru2S3 nanoparticles are capped through the interaction of the –NH2 group of hexadecylamine HDA adsorbed on the surfaces of nanoparticles and it also showed that oleic acid (OA) is acting as both coordinating stabilizing surfactant and capping agent. The XRD confirmed the successful formation of Ru2S3 nanoparticles induced by the thermal decomposition of series of [Ru(S2CNR2)3] complexes. The diffraction peaks: 2θ = 29.43, 40.54, 49.33, 51.86, 61.92, and 75.94 were assign the Miler indices (hkl) to be (111), (211), (220), (300), (222) and (330) reflections, respectively, and were found to be in agreement with a cubic crystal structure reported in database file of (JCPDS 19-1107). The particle sizes estimated from Scherer's equation were found in a range between 2.5 and 4.9 nm. EDS spectra reveal that the prepared nanoparticles are mainly composed of Ru and S, confirming the presence of Ru2S3 nanoparticles in cubic phase. The inner morphology of nanoparticles was obtained by transmission electron microscopy (TEM) and most nanoparticles had narrow particle size distribution characterized by an average diameter of 8.45 nm with a standard deviation of 1.6 nm. The optical band gap (Eg) determined from Tauc plot was found in the range (3.44 to 4.18 eV) values.
- Full Text:
- Authors: Mbese, Johannes Zanoxolo
- Date: 2017
- Subjects: Nanoparticles Ruthenium compounds
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/15420 , vital:40406
- Description: The present Thesis pioneer the application of single-source molecular precursor method for the synthesis of ruthenium sulfide nanoparticles using a series of novel self-prepared single-source molecular precursors. The preparation of precursors involved the design and synthesis of compounds containing all the desired elements required within the coordination compound. Good precursors are tailored to give reproducible, clean decomposition at moderate temperatures, leading to high quality, defect free, mono-dispersed nanoparticles. Nine (9) homonuclear tris-dithiocarbamato ruthenium(III) complexes, [Ru(S2CNR2)3] were prepared from a stoichiometric reaction of RuCl3·H2O with self-prepared dithiocarbamate ligands at room temperature in a molar ratio of Ru3+: Ligand of 1:3. Dithiocarbamate ligands were derived from a stoichiometric reaction of carbon disulfide with (aniline, N-allylmethylamine, p-toluidine, p-anisidine, N-ethyl-m-toluidine, piperidine, morpholine, di-isopropylamine, and diallylamine) in the presence of concentrated ammonia or potassium hydroxide in ice cold bath. The dithiocarbamate ligands and complexes were characterized by elemental analyses, UV-Vis, Fourier transform infrared spectroscopy (FTIR), 1H- and 13C-NMR spectroscopy. Thermogravimetric analyses (TGA) was used to study the decomposition profiles of the precursor complexes. The results obtained from the TGA of precursors showed that the complexes decompose to ruthenium sulfide nanoparticles. The FTIR spectra of the ligands revealed prominent strong absorption bands ascribed to v(N-H) stretching vibrations and also confirm the bidentate coordination of the dithiocarbamate ligands. Ruthenium(III) complexes show absorption spectra in the visible region that exhibit bands attributed to n → π* electronic transitions located on the sulfur atoms located in the S–C–S and N–C–S chromophores of the bidentate dithiocarbamate ligands respectively. The absorption spectra also confirmed the geometry of ruthenium(III) complexes to be octahedral. The proposed structures of dithiocarbamate ligands and ruthenium(III) complexes were confirmed by the 1H- and 13C-NMR. The complexes were used as single-source molecular precursors for the synthesis of ruthenium sulfide nanoparticles. The structural and optical properties were studied using transmission electron microscope (TEM), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), UV-Vis absorption and photoluminescence (PL) spectra. FTIR revealed that Ru2S3 nanoparticles are capped through the interaction of the –NH2 group of hexadecylamine HDA adsorbed on the surfaces of nanoparticles and it also showed that oleic acid (OA) is acting as both coordinating stabilizing surfactant and capping agent. The XRD confirmed the successful formation of Ru2S3 nanoparticles induced by the thermal decomposition of series of [Ru(S2CNR2)3] complexes. The diffraction peaks: 2θ = 29.43, 40.54, 49.33, 51.86, 61.92, and 75.94 were assign the Miler indices (hkl) to be (111), (211), (220), (300), (222) and (330) reflections, respectively, and were found to be in agreement with a cubic crystal structure reported in database file of (JCPDS 19-1107). The particle sizes estimated from Scherer's equation were found in a range between 2.5 and 4.9 nm. EDS spectra reveal that the prepared nanoparticles are mainly composed of Ru and S, confirming the presence of Ru2S3 nanoparticles in cubic phase. The inner morphology of nanoparticles was obtained by transmission electron microscopy (TEM) and most nanoparticles had narrow particle size distribution characterized by an average diameter of 8.45 nm with a standard deviation of 1.6 nm. The optical band gap (Eg) determined from Tauc plot was found in the range (3.44 to 4.18 eV) values.
- Full Text:
Screening of shark liver extracts for potential antimicrobial properties against selected pathogenic bacterial strains
- Authors: Mrwetyana, Thandolwethu
- Date: 2017
- Subjects: Fishes -- Diseases Pathogenic bacteria
- Language: English
- Type: Thesis , Masters , Microbiology
- Identifier: http://hdl.handle.net/10353/13004 , vital:39431
- Description: The growing problem of antimicrobial resistance prevents the effective treatment of bacterial infections. Traditional antibiotics such as penicillin have been rendered ineffective against most microbial pathogens. This has led to an increased need for the development of new and improved drugs. The marine environment contains a great array of organisms with unique biological properties, but still remains one of our most underutilized biological resources. The aim of this study was to screen different shark liver extracts for antimicrobial properties. After optimizing the extraction methods, the liver extracts (oil and aminosterol) of three different shark species, namely the Dogfish (Squalus acanthias), the Catshark (Scyliorhinus capensis) and the Hammerhead (Sphyrna zygaena) shark, were screened for antimicrobial properties using the Kirby-Bauer disc diffusion method against selected bacterial pathogens (Helicobacter pylori, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus cereus), after which the MIC was determined using the modified broth micro-dilution described by Vollekova et al. (2001). The most active extract was fractionated using thin layer chromatography, and TLC-direct bioautography was used to determine the antimicrobial properties of the fractionated compounds. The Folch et al and the Shinnar et al methods yielded the highest extract volumes for oil and aminosterol consecutively, and the catshark and dogfish aminosterol extract showed greater levels of bioactivity against all selected bacterial pathogens, with S. aureus showing highest susceptibility levels to both extracts. A total of 22 compounds were observed in the developed plates with two compounds (Rf 0.53 and 0.79) showing antimicrobial activity. Certain shark liver extracts possess antimicrobial properties that have the potential to be used in the development of new antimicrobial drugs.
- Full Text:
- Authors: Mrwetyana, Thandolwethu
- Date: 2017
- Subjects: Fishes -- Diseases Pathogenic bacteria
- Language: English
- Type: Thesis , Masters , Microbiology
- Identifier: http://hdl.handle.net/10353/13004 , vital:39431
- Description: The growing problem of antimicrobial resistance prevents the effective treatment of bacterial infections. Traditional antibiotics such as penicillin have been rendered ineffective against most microbial pathogens. This has led to an increased need for the development of new and improved drugs. The marine environment contains a great array of organisms with unique biological properties, but still remains one of our most underutilized biological resources. The aim of this study was to screen different shark liver extracts for antimicrobial properties. After optimizing the extraction methods, the liver extracts (oil and aminosterol) of three different shark species, namely the Dogfish (Squalus acanthias), the Catshark (Scyliorhinus capensis) and the Hammerhead (Sphyrna zygaena) shark, were screened for antimicrobial properties using the Kirby-Bauer disc diffusion method against selected bacterial pathogens (Helicobacter pylori, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus cereus), after which the MIC was determined using the modified broth micro-dilution described by Vollekova et al. (2001). The most active extract was fractionated using thin layer chromatography, and TLC-direct bioautography was used to determine the antimicrobial properties of the fractionated compounds. The Folch et al and the Shinnar et al methods yielded the highest extract volumes for oil and aminosterol consecutively, and the catshark and dogfish aminosterol extract showed greater levels of bioactivity against all selected bacterial pathogens, with S. aureus showing highest susceptibility levels to both extracts. A total of 22 compounds were observed in the developed plates with two compounds (Rf 0.53 and 0.79) showing antimicrobial activity. Certain shark liver extracts possess antimicrobial properties that have the potential to be used in the development of new antimicrobial drugs.
- Full Text:
Screening of shark liver extracts for potential antimicrobial properties against selected pathogenic bacterial strains
- Authors: Mrwetyana, Thandolwethu
- Date: 2017
- Subjects: Fishes -- Diseases Pathogenic bacteria Antibiotics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12982 , vital:39413
- Description: The growing problem of antimicrobial resistance prevents the effective treatment of bacterial infections. Traditional antibiotics such as penicillin have been rendered ineffective against most microbial pathogens. This has led to an increased need for the development of new and improved drugs. The marine environment contains a great array of organisms with unique biological properties, but still remains one of our most underutilized biological resources. The aim of this study was to screen different shark liver extracts for antimicrobial properties. After optimizing the extraction methods, the liver extracts (oil and aminosterol) of three different shark species, namely the Dogfish (Squalus acanthias), the Catshark (Scyliorhinus capensis) and the Hammerhead (Sphyrna zygaena) shark, were screened for antimicrobial properties using the Kirby-Bauer disc diffusion method against selected bacterial pathogens (Helicobacter pylori, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus cereus), after which the MIC was determined using the modified broth micro-dilution described by Vollekova et al. (2001). The most active extract was fractionated using thin layer chromatography, and TLC-direct bioautography was used to determine the antimicrobial properties of the fractionated compounds. The Folch et al and the Shinnar et al methods yielded the highest extract volumes for oil and aminosterol consecutively, and the catshark and dogfish aminosterol extract showed greater levels of bioactivity against all selected bacterial pathogens, with S. aureus showing highest susceptibility levels to both extracts. A total of 22 compounds were observed in the developed plates with two compounds (Rf 0.53 and 0.79) showing antimicrobial activity. Certain shark liver extracts possess antimicrobial properties that have the potential to be used in the development of new antimicrobial drugs.
- Full Text:
- Authors: Mrwetyana, Thandolwethu
- Date: 2017
- Subjects: Fishes -- Diseases Pathogenic bacteria Antibiotics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12982 , vital:39413
- Description: The growing problem of antimicrobial resistance prevents the effective treatment of bacterial infections. Traditional antibiotics such as penicillin have been rendered ineffective against most microbial pathogens. This has led to an increased need for the development of new and improved drugs. The marine environment contains a great array of organisms with unique biological properties, but still remains one of our most underutilized biological resources. The aim of this study was to screen different shark liver extracts for antimicrobial properties. After optimizing the extraction methods, the liver extracts (oil and aminosterol) of three different shark species, namely the Dogfish (Squalus acanthias), the Catshark (Scyliorhinus capensis) and the Hammerhead (Sphyrna zygaena) shark, were screened for antimicrobial properties using the Kirby-Bauer disc diffusion method against selected bacterial pathogens (Helicobacter pylori, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus cereus), after which the MIC was determined using the modified broth micro-dilution described by Vollekova et al. (2001). The most active extract was fractionated using thin layer chromatography, and TLC-direct bioautography was used to determine the antimicrobial properties of the fractionated compounds. The Folch et al and the Shinnar et al methods yielded the highest extract volumes for oil and aminosterol consecutively, and the catshark and dogfish aminosterol extract showed greater levels of bioactivity against all selected bacterial pathogens, with S. aureus showing highest susceptibility levels to both extracts. A total of 22 compounds were observed in the developed plates with two compounds (Rf 0.53 and 0.79) showing antimicrobial activity. Certain shark liver extracts possess antimicrobial properties that have the potential to be used in the development of new antimicrobial drugs.
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Seasonal variations in tick loads, coat characteristics, temperature-humidity index and blood metabolite profiles of extensively raised Boran cows
- Authors: Ntilini, Wonga John
- Date: 2017
- Subjects: Boran cattle -- South Africa Ticks -- South Africa
- Language: English
- Type: Thesis , Masters , MAgric
- Identifier: http://hdl.handle.net/10353/13471 , vital:39672
- Description: This study sought to determine the seasonal variations in tick loads, coat characteristics, temperature-humidity index and blood metabolite profiles of Boran cows reared in arid rangelands of South Africa. A total of 20 Boran cows of different age groups were used in this study. Tick counts, hair length, coat score, average temperature and relative humidity readings were measured twice (beginning and end) in each season (post-rainy, cold-dry, hot-dry, hot-wet). Blood samples were taken seasonally (beginning and end of the season) for the analysis of creatine kinase (CK) activity and haematological parameters (HP). Ticks were observed and counted from different anatomical sites, namely anterior (neck, head, ears, and around eyes), ventral (belly, udder, and limbs) and posterior (back and under the tail). The tick species observed from the Boran cows were Rhipicephalus evertsi evertsi (34.58percent), Amblyomma hebreaum (43.35percent), Rhipicephalus simus (4.48percent) and Rhipicephalus (Boophilus) decoloratus (17.59percent). Significant differences were observed in tick burdens at various anatomical sites, with posterior position having the highest tick loads during the post-rainy, cold-dry and hot-dry season. While the ventral position recorded the highest tick loads during the hot-wet season. It was also observed that the cattle had significantly long hair lengths during the cold-dry season. Furthermore, coat score and hair length were observed to be negatively (P<0.05) correlated with tick counts, while coat scores were positively (P<0.05) correlated with hair length. Significant differences were observed in CK activity across season, with higher levels during the hot-dry and hot-wet seasons compared to the post-rainy and cold-dry seasons. Boran cows were exposed to a mild stress condition during the hot-dry and hot-wet season when the THI values were high (>70). Seasonal variations had an effect (P<0.05) on some HP (HB, HCT, MCV, MCH, EOS, and BAS). Neutrophils (-0.267) and basophils (0.268) were significantly correlated with THI. In conclusion, the Boran cows were more susceptible to tick loads during the hot seasons. Likewise, the levels of creatine kinase activity and temperature-humidity index were high during the hot-dry and hot-wet season. Therefore, seasonal variations had an effect on tick loads, coat characteristics, temperature-humidity index and blood metabolite profiles of extensively raised Boran cows.
- Full Text:
- Authors: Ntilini, Wonga John
- Date: 2017
- Subjects: Boran cattle -- South Africa Ticks -- South Africa
- Language: English
- Type: Thesis , Masters , MAgric
- Identifier: http://hdl.handle.net/10353/13471 , vital:39672
- Description: This study sought to determine the seasonal variations in tick loads, coat characteristics, temperature-humidity index and blood metabolite profiles of Boran cows reared in arid rangelands of South Africa. A total of 20 Boran cows of different age groups were used in this study. Tick counts, hair length, coat score, average temperature and relative humidity readings were measured twice (beginning and end) in each season (post-rainy, cold-dry, hot-dry, hot-wet). Blood samples were taken seasonally (beginning and end of the season) for the analysis of creatine kinase (CK) activity and haematological parameters (HP). Ticks were observed and counted from different anatomical sites, namely anterior (neck, head, ears, and around eyes), ventral (belly, udder, and limbs) and posterior (back and under the tail). The tick species observed from the Boran cows were Rhipicephalus evertsi evertsi (34.58percent), Amblyomma hebreaum (43.35percent), Rhipicephalus simus (4.48percent) and Rhipicephalus (Boophilus) decoloratus (17.59percent). Significant differences were observed in tick burdens at various anatomical sites, with posterior position having the highest tick loads during the post-rainy, cold-dry and hot-dry season. While the ventral position recorded the highest tick loads during the hot-wet season. It was also observed that the cattle had significantly long hair lengths during the cold-dry season. Furthermore, coat score and hair length were observed to be negatively (P<0.05) correlated with tick counts, while coat scores were positively (P<0.05) correlated with hair length. Significant differences were observed in CK activity across season, with higher levels during the hot-dry and hot-wet seasons compared to the post-rainy and cold-dry seasons. Boran cows were exposed to a mild stress condition during the hot-dry and hot-wet season when the THI values were high (>70). Seasonal variations had an effect (P<0.05) on some HP (HB, HCT, MCV, MCH, EOS, and BAS). Neutrophils (-0.267) and basophils (0.268) were significantly correlated with THI. In conclusion, the Boran cows were more susceptible to tick loads during the hot seasons. Likewise, the levels of creatine kinase activity and temperature-humidity index were high during the hot-dry and hot-wet season. Therefore, seasonal variations had an effect on tick loads, coat characteristics, temperature-humidity index and blood metabolite profiles of extensively raised Boran cows.
- Full Text:
Sedimentary, geochemical and geophysical study of the Ecca group, Karoo supergroup and its hydrocarbon potential in the Eastern Cape Province, South Africa
- Authors: Baiyegunhi, Christopher
- Date: 2017
- Subjects: Sediments (Geology) -- South Africa -- Eastern Cape Sedimentology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/4881 , vital:28658
- Description: The Ecca Group of Karoo Supergroup is a sedimentary rock sequence that deposited between the Late Carboniferous (Dwyka Group) and the Late Permian-Middle Triassic (Beaufort Group). The Ecca Group investigated in this study is situated in the Eastern Cape Province of South Africa and it comprises mainly of shales, mudstones, siltstones and sandstones. The Ecca Group sequence contains considerable carbon content and suitable thickness to make it an ideal target for shale gas exploration. Previous studies put more emphasis on the geology and stratigraphy of the Ecca Group, this study revised the stratigraphy, and put new insight on the petrography, depositional processes, sedimentary facies, provenance, paleoweathering, tectonic setting, subsidence rates and history, electrical resistivity, source rock characteristics and diagenesis of the potentially feasible sandstone and mudrock reservoir rocks of the Ecca Group. Based on the lithological features, sedimentary structures and facies characteristics, the stratigraphy of the Prince Albert, Whitehill, Collingham and Fort Brown Formations of the Ecca Group is now subdivided into two informal members each, i.e. Lower Member and Upper Member. Furthermore, the Ripon Formation is now subdivided into three informal members. Each member has been asigned a lithological name. The grain size parameters show that most of the Ecca Group sandstones are very fine to fine grained, poorly to moderately well sorted, mostly near-symmetrical and mesokurtic in grain-size distribution. The linear discriminant function analysis is dominantly indicative of turbidity current deposits under deep marine environment for Prince Albert, Whitehill and Collingham Formations, shallow marine environment for Ripon Formation, while the Fort Brown Formation is lacustrine-deltaic deposits. Modal composition analysis and petrography studies revealed that the detrital components of the sandstones are dominated by monocrystalline quartz, feldspar and lithic fragments. The sandstones are compositionally and texturally immature and can be classified as feldspathic wacke and lithic wacke. The provenance analysis revealed plutonic and metamorphic terrains as the main source rocks with minor debris derived from recycled sedimentary rocks. The detrital modal compositions of these sandstones are related to back arc to island and continental margin of tectonic setting. Based on the detailed sedimentological analyses of outcrop and borehole data, fourteen lithofacies were identified and seven facies associations (FAs) were recognised. The facies associations are: FA 1: Shale and mudstones intercalated with siltstones, FA 2: Carbonaceous shale, mudstone with subordinate chert and sandstone, FA 3: Mudstones rhythmite with thin bedded mudstone and lenticular siltstone, FA 4: Greyish medium bedded sandstone intercalated with laminated mudstone, FA 5: Dark-grey medium to thick bedded mudstone and siltstone, FA 6: Thin to medium bedded sandstone alternated with thin bedded carbonaceous mudstone, and FA 7: Varved mudstone rhythmite intercalated with siltstone and minor sandstone. Sedimentological characteristics of the identified facies associations indicate four deposition environments, namely, deep marine basin, turbidite, shallow marine and lacustrine environments, which constitute a gradually regression sequence as a result of sea-level dropping and shallowing of the basin during the developmental processes. Geochemical analysis of the Ecca mudrocks and sandstones revealed that the rocks are of quartzose sedimentary provenance, suggesting that they were derived from a cratonic interior or recycled orogen. The petrography and geochemistry of the sandstones indicated that the source areas are composed of plutonic and metamorphic rocks with a minor component from sedimentary rocks. The geochemical diagrams and indices of weathering suggested that the granitic source rocks underwent moderate to high degree of chemical weathering. The tectonic setting discrimination diagrams support passive continental margin setting of the provenance.
- Full Text:
- Authors: Baiyegunhi, Christopher
- Date: 2017
- Subjects: Sediments (Geology) -- South Africa -- Eastern Cape Sedimentology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/4881 , vital:28658
- Description: The Ecca Group of Karoo Supergroup is a sedimentary rock sequence that deposited between the Late Carboniferous (Dwyka Group) and the Late Permian-Middle Triassic (Beaufort Group). The Ecca Group investigated in this study is situated in the Eastern Cape Province of South Africa and it comprises mainly of shales, mudstones, siltstones and sandstones. The Ecca Group sequence contains considerable carbon content and suitable thickness to make it an ideal target for shale gas exploration. Previous studies put more emphasis on the geology and stratigraphy of the Ecca Group, this study revised the stratigraphy, and put new insight on the petrography, depositional processes, sedimentary facies, provenance, paleoweathering, tectonic setting, subsidence rates and history, electrical resistivity, source rock characteristics and diagenesis of the potentially feasible sandstone and mudrock reservoir rocks of the Ecca Group. Based on the lithological features, sedimentary structures and facies characteristics, the stratigraphy of the Prince Albert, Whitehill, Collingham and Fort Brown Formations of the Ecca Group is now subdivided into two informal members each, i.e. Lower Member and Upper Member. Furthermore, the Ripon Formation is now subdivided into three informal members. Each member has been asigned a lithological name. The grain size parameters show that most of the Ecca Group sandstones are very fine to fine grained, poorly to moderately well sorted, mostly near-symmetrical and mesokurtic in grain-size distribution. The linear discriminant function analysis is dominantly indicative of turbidity current deposits under deep marine environment for Prince Albert, Whitehill and Collingham Formations, shallow marine environment for Ripon Formation, while the Fort Brown Formation is lacustrine-deltaic deposits. Modal composition analysis and petrography studies revealed that the detrital components of the sandstones are dominated by monocrystalline quartz, feldspar and lithic fragments. The sandstones are compositionally and texturally immature and can be classified as feldspathic wacke and lithic wacke. The provenance analysis revealed plutonic and metamorphic terrains as the main source rocks with minor debris derived from recycled sedimentary rocks. The detrital modal compositions of these sandstones are related to back arc to island and continental margin of tectonic setting. Based on the detailed sedimentological analyses of outcrop and borehole data, fourteen lithofacies were identified and seven facies associations (FAs) were recognised. The facies associations are: FA 1: Shale and mudstones intercalated with siltstones, FA 2: Carbonaceous shale, mudstone with subordinate chert and sandstone, FA 3: Mudstones rhythmite with thin bedded mudstone and lenticular siltstone, FA 4: Greyish medium bedded sandstone intercalated with laminated mudstone, FA 5: Dark-grey medium to thick bedded mudstone and siltstone, FA 6: Thin to medium bedded sandstone alternated with thin bedded carbonaceous mudstone, and FA 7: Varved mudstone rhythmite intercalated with siltstone and minor sandstone. Sedimentological characteristics of the identified facies associations indicate four deposition environments, namely, deep marine basin, turbidite, shallow marine and lacustrine environments, which constitute a gradually regression sequence as a result of sea-level dropping and shallowing of the basin during the developmental processes. Geochemical analysis of the Ecca mudrocks and sandstones revealed that the rocks are of quartzose sedimentary provenance, suggesting that they were derived from a cratonic interior or recycled orogen. The petrography and geochemistry of the sandstones indicated that the source areas are composed of plutonic and metamorphic rocks with a minor component from sedimentary rocks. The geochemical diagrams and indices of weathering suggested that the granitic source rocks underwent moderate to high degree of chemical weathering. The tectonic setting discrimination diagrams support passive continental margin setting of the provenance.
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Small-scale farmers' participation in planning and implementation of farmer support programmes in Amahlathi Local Municipality, Eastern Cape Province, South Africa
- Authors: Makunga, Phendulwa Zikhona
- Date: 2017
- Subjects: Agricultural development projects , Farms, Small -- South Africa -- Eastern Cape , Agriculture -- Economic aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/6248 , vital:29529
- Description: The democratic government in South Africa has brought about several policies which were initiated for rural development, and one of the government’s strategies was to involve the agricultural sector. Farmer Support Programmes (FSPs) were developed to assist small-scale farmers to become commercial farmers. The study looked at the participation of small scale farmers in the planning and implementation of the FSPs in the Amahlathi Local Municipality. 108 small scale farmers were selected using a non-random purposive probability and twelve farmers’ organisations. Semi-structured questionnaires and semi-structured interviews were used as the data collection tool and method respectively. The data analysis used was a descriptive analysis and a thematic analysis. The results revealed that the farmers have a positive perception towards the support programmes being helpful in their farming needs. The positive perception was especially on the extension and advisory services, dipping and vaccination programme, and the supply and funding of inputs and assets. However, the results revealed that there was no significant difference between gender and the perception of the farmers when a chi square test of association was performed. The results also revealed that the farmers and farmers’ organisations were not involved in the planning of the programmes by the government. It is therefore recommended that for the success of the FSP and for economic growth in the rural areas, the government has to avoid using a top-down approach when developing these programmes, and instead consult the farmers and the farmers’ organisations to know the specific needs of the farmers in their farming practices.
- Full Text:
- Authors: Makunga, Phendulwa Zikhona
- Date: 2017
- Subjects: Agricultural development projects , Farms, Small -- South Africa -- Eastern Cape , Agriculture -- Economic aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/6248 , vital:29529
- Description: The democratic government in South Africa has brought about several policies which were initiated for rural development, and one of the government’s strategies was to involve the agricultural sector. Farmer Support Programmes (FSPs) were developed to assist small-scale farmers to become commercial farmers. The study looked at the participation of small scale farmers in the planning and implementation of the FSPs in the Amahlathi Local Municipality. 108 small scale farmers were selected using a non-random purposive probability and twelve farmers’ organisations. Semi-structured questionnaires and semi-structured interviews were used as the data collection tool and method respectively. The data analysis used was a descriptive analysis and a thematic analysis. The results revealed that the farmers have a positive perception towards the support programmes being helpful in their farming needs. The positive perception was especially on the extension and advisory services, dipping and vaccination programme, and the supply and funding of inputs and assets. However, the results revealed that there was no significant difference between gender and the perception of the farmers when a chi square test of association was performed. The results also revealed that the farmers and farmers’ organisations were not involved in the planning of the programmes by the government. It is therefore recommended that for the success of the FSP and for economic growth in the rural areas, the government has to avoid using a top-down approach when developing these programmes, and instead consult the farmers and the farmers’ organisations to know the specific needs of the farmers in their farming practices.
- Full Text:
Smallholder farmer's climate change knowledge in Ngqushwa Local Municipality, Eastern Cape : implications on coping and adaptation
- Authors: Shoko, Witness Alvis
- Date: 2017
- Subjects: Climatic changes -- South Africa -- Eastern Cape Farms, Small -- South Africa -- Eastern Cape Sustainable agriculture
- Language: English
- Type: Thesis , Masters , MSoc
- Identifier: http://hdl.handle.net/10353/6480 , vital:29744
- Description: Lack of knowledge about climate change poses a greater risk to human development in general. This study emerges from the premise that agriculture, and more specifically smallholder farmers, are the most affected by climate variability due to the type of assets they hold. Among other factors, climate change can directly and adversely impact the ability of smallholder farmers to sustain their livelihoods. Taking into consideration spatial differences across Ngqushwa Local Municipality, smallholder farmers in different areas have to understand the constraints they face that emanate from climate change. The study aimed to explore the knowledge that smallholder farmers in Ngqushwa local municipality have on climate change, strategies they utilise to cope and minimise the detrimental effects of climate change. The study also focused on climate change information sources namely, meteorological and Indigenous Knowledge (IK) that smallholder farmers have at their disposal for coping and adaptation to climate change. Furthermore, the study analyses comprehensiveness and usefulness of information that the resource-poor farmers possess. The findings of this study show that smallholder farmers in Ngqushwa local municipality access climate change information through televisions, newspapers and listening to the radio. Their knowledge of the behaviour of birds, moon, wind, and insects is also an important source of forecasting weather patterns. Recommendations from this study include the following: enhancing and widening the sources of climate change information, education encompassing the nature of climate change, networking of smallholder farmers, linking meteorological and indigenous knowledge and supplementing natural water supply.
- Full Text:
- Authors: Shoko, Witness Alvis
- Date: 2017
- Subjects: Climatic changes -- South Africa -- Eastern Cape Farms, Small -- South Africa -- Eastern Cape Sustainable agriculture
- Language: English
- Type: Thesis , Masters , MSoc
- Identifier: http://hdl.handle.net/10353/6480 , vital:29744
- Description: Lack of knowledge about climate change poses a greater risk to human development in general. This study emerges from the premise that agriculture, and more specifically smallholder farmers, are the most affected by climate variability due to the type of assets they hold. Among other factors, climate change can directly and adversely impact the ability of smallholder farmers to sustain their livelihoods. Taking into consideration spatial differences across Ngqushwa Local Municipality, smallholder farmers in different areas have to understand the constraints they face that emanate from climate change. The study aimed to explore the knowledge that smallholder farmers in Ngqushwa local municipality have on climate change, strategies they utilise to cope and minimise the detrimental effects of climate change. The study also focused on climate change information sources namely, meteorological and Indigenous Knowledge (IK) that smallholder farmers have at their disposal for coping and adaptation to climate change. Furthermore, the study analyses comprehensiveness and usefulness of information that the resource-poor farmers possess. The findings of this study show that smallholder farmers in Ngqushwa local municipality access climate change information through televisions, newspapers and listening to the radio. Their knowledge of the behaviour of birds, moon, wind, and insects is also an important source of forecasting weather patterns. Recommendations from this study include the following: enhancing and widening the sources of climate change information, education encompassing the nature of climate change, networking of smallholder farmers, linking meteorological and indigenous knowledge and supplementing natural water supply.
- Full Text:
Socio-economic benefits of agricultural projects to surrounding communities: the case of Qamata Irrigation Scheme in the Eastern Cape, South Africa
- Authors: Masela, Zandile
- Date: 2017
- Subjects: Agricultural development projects -- South Africa -- Eastern Cape , Agriculture -- Economic aspects -- South Africa -- Eastern Cape , Irrigation farming -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/4716 , vital:28501
- Description: The Qamata Irrigation Scheme (QIS) is one of the largest irrigation schemes in South Africa. Despite substantial state investment, community members have only derived limited benefits from the scheme, leading the government efforts to revitalize the scheme. Many studies have been conducted about QIS but none of them have analyzed the effects of the QIS on the surrounding communities. This study investigated the socio-economic benefits of QIS to surrounding communities. For the purposes of this study, the units of analysis were the surrounding household members, questionnaires were used to collect data. Probabilistic sampling of random sampling method was used to select the villages; respondents’ were availability selected with sample size of 197 households. Quantitative and qualitative data were collected from the participants. To analyse data, descriptive statistics and multinomial logit regression model were used. The study found out that female-headed households constitute 63.45 percent compared to male-headed households at 36.55 percent. The average age of the households in the villages that are within the radius of 10km is 58 years, while it is 59 years in villages that are beyond the 10km radius. In villages within the radius of 10km, 86.08 percent of respondents are unemployed, 5.70 percent are employed at the scheme and 8.23 percent are self-employed. In villages beyond 10km, 84.62 percent of respondents are unemployed, 5.13 percent are employed at the scheme and 10.26 percent are self-employed. In both villages, 71 percent of respondents reported that that they do not get feed supply from the scheme while 29 percent of respondents reported that they get feed supply from the scheme. From the overall distribution of villages within and beyond the radius of 10km, 80 percent of respondents reported that they do not get job opportunities from the QIS while 20 percent of respondents reported that they get job opportunities from the QIS. The study shows that 53 percent of respondents from villages within the radius of 10km are low-benefitting, 33 percent of respondents are intermediate-benefitting and 14 percent of respondents are high-benefitting from the scheme, while in villages beyond the radius of 10km, 97 percent of respondents are low-benefitting, 3 percent of respondents are intermediate-benefitting and none of the respondents is high-benefitting from the scheme. Furthermore, the study, through the multinomial logit regression model, shows that gender for intermediate benefitting has a negative coefficient (-1.70) and shows a significance of 10 percent On the other hand, gender for high benefitting has a positive coefficient (2.57) and shows a significance of 1 percent. Distance from the scheme has a negative coefficient (-3.08) and shows a significance of 1 percent. Access to farmland has a positive coefficient (2.33) and shows a significance of 10 percent. The study recommends that surrounding communities should own home gardens so that they can grow fresh produce and create job opportunities. The surrounding communities are also encouraged to own more farmlands or produce their own crops so they can also learn from the skills of the scheme.
- Full Text:
- Authors: Masela, Zandile
- Date: 2017
- Subjects: Agricultural development projects -- South Africa -- Eastern Cape , Agriculture -- Economic aspects -- South Africa -- Eastern Cape , Irrigation farming -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/4716 , vital:28501
- Description: The Qamata Irrigation Scheme (QIS) is one of the largest irrigation schemes in South Africa. Despite substantial state investment, community members have only derived limited benefits from the scheme, leading the government efforts to revitalize the scheme. Many studies have been conducted about QIS but none of them have analyzed the effects of the QIS on the surrounding communities. This study investigated the socio-economic benefits of QIS to surrounding communities. For the purposes of this study, the units of analysis were the surrounding household members, questionnaires were used to collect data. Probabilistic sampling of random sampling method was used to select the villages; respondents’ were availability selected with sample size of 197 households. Quantitative and qualitative data were collected from the participants. To analyse data, descriptive statistics and multinomial logit regression model were used. The study found out that female-headed households constitute 63.45 percent compared to male-headed households at 36.55 percent. The average age of the households in the villages that are within the radius of 10km is 58 years, while it is 59 years in villages that are beyond the 10km radius. In villages within the radius of 10km, 86.08 percent of respondents are unemployed, 5.70 percent are employed at the scheme and 8.23 percent are self-employed. In villages beyond 10km, 84.62 percent of respondents are unemployed, 5.13 percent are employed at the scheme and 10.26 percent are self-employed. In both villages, 71 percent of respondents reported that that they do not get feed supply from the scheme while 29 percent of respondents reported that they get feed supply from the scheme. From the overall distribution of villages within and beyond the radius of 10km, 80 percent of respondents reported that they do not get job opportunities from the QIS while 20 percent of respondents reported that they get job opportunities from the QIS. The study shows that 53 percent of respondents from villages within the radius of 10km are low-benefitting, 33 percent of respondents are intermediate-benefitting and 14 percent of respondents are high-benefitting from the scheme, while in villages beyond the radius of 10km, 97 percent of respondents are low-benefitting, 3 percent of respondents are intermediate-benefitting and none of the respondents is high-benefitting from the scheme. Furthermore, the study, through the multinomial logit regression model, shows that gender for intermediate benefitting has a negative coefficient (-1.70) and shows a significance of 10 percent On the other hand, gender for high benefitting has a positive coefficient (2.57) and shows a significance of 1 percent. Distance from the scheme has a negative coefficient (-3.08) and shows a significance of 1 percent. Access to farmland has a positive coefficient (2.33) and shows a significance of 10 percent. The study recommends that surrounding communities should own home gardens so that they can grow fresh produce and create job opportunities. The surrounding communities are also encouraged to own more farmlands or produce their own crops so they can also learn from the skills of the scheme.
- Full Text:
Spatial and seasonal distribution of selected persistent organic pollutants and phenolic derivatives along the course of the Buffalo River in the Eastern Cape Province of South Africa
- Authors: Yahaya, Abdulrazaq
- Date: 2017
- Subjects: Organic water pollutants Water -- Purification -- Organic compounds removal
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/5939 , vital:29448
- Description:
Persistent organic pollutants (POPs) fall under a group of synthetic chemicals known for their persistence in environmental matrices such as soil and water, and are used in industrial, domestic and agricultural applications. Because of their volatility and lipophilicity, POPs can be transported far away from their point sources and bio-accumulate in food and in fatty tissues of humans and animals. In view of their toxicity and carcinogenicity some organic pollutants such as polychlorinated biphenyl (PCBs), organochlorine pesticides (OCPs) and phenolic derivatives (chlorophenol and nitrophenol) have been classified by United State Environmental Protection Agency (USEPA) and World Health Organization (WHO) as priority pollutants. The present work evaluated the distribution patterns of 19 polychlorinated biphenyls congeners, 17 organochlorine pesticides and selected phenolic derivatives (USEPA 11-priority pollutants) in the Buffalo River, in the Eastern Cape Province, South Africa between December 2015 and May 2016. The Liquid-liquid extraction technique was used for PCBs, OCPs and phenolic derivatives in the river water samples. Silica gel and florisil clean up were carried out for PCBs and OCPs samples respectively and analyzed with gas chromatography electron capture detector (GC/ECD). Phenolic compounds were derivatized and analyzed by gas chromatography mass spectrometer (GC/MS). Limits of detection (LOD), limit of quantitation (LOQ) and relative standard deviation (RSD) for the PCBs were 10 to 330 ng/L, 20 to 1,060 ng/L and 1.18 to 14.1 percent respectively. The LOD, LOQ and RSD for the OCPs were from 20 - 60 ng/L, 110 - 530 ng/L and 0.02 - 0.06 percent, while the corresponding values for the phenolic derivatives were 10 to 70 ng/L, 33 to 222 ng/L and 1.99 - 10.86 percent. In summer, the concentrations of PCBs, OCPs and phenolic derivatives ranged from
- Full Text:
- Authors: Yahaya, Abdulrazaq
- Date: 2017
- Subjects: Organic water pollutants Water -- Purification -- Organic compounds removal
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/5939 , vital:29448
- Description:
Persistent organic pollutants (POPs) fall under a group of synthetic chemicals known for their persistence in environmental matrices such as soil and water, and are used in industrial, domestic and agricultural applications. Because of their volatility and lipophilicity, POPs can be transported far away from their point sources and bio-accumulate in food and in fatty tissues of humans and animals. In view of their toxicity and carcinogenicity some organic pollutants such as polychlorinated biphenyl (PCBs), organochlorine pesticides (OCPs) and phenolic derivatives (chlorophenol and nitrophenol) have been classified by United State Environmental Protection Agency (USEPA) and World Health Organization (WHO) as priority pollutants. The present work evaluated the distribution patterns of 19 polychlorinated biphenyls congeners, 17 organochlorine pesticides and selected phenolic derivatives (USEPA 11-priority pollutants) in the Buffalo River, in the Eastern Cape Province, South Africa between December 2015 and May 2016. The Liquid-liquid extraction technique was used for PCBs, OCPs and phenolic derivatives in the river water samples. Silica gel and florisil clean up were carried out for PCBs and OCPs samples respectively and analyzed with gas chromatography electron capture detector (GC/ECD). Phenolic compounds were derivatized and analyzed by gas chromatography mass spectrometer (GC/MS). Limits of detection (LOD), limit of quantitation (LOQ) and relative standard deviation (RSD) for the PCBs were 10 to 330 ng/L, 20 to 1,060 ng/L and 1.18 to 14.1 percent respectively. The LOD, LOQ and RSD for the OCPs were from 20 - 60 ng/L, 110 - 530 ng/L and 0.02 - 0.06 percent, while the corresponding values for the phenolic derivatives were 10 to 70 ng/L, 33 to 222 ng/L and 1.99 - 10.86 percent. In summer, the concentrations of PCBs, OCPs and phenolic derivatives ranged from
- Full Text:
Species composition and seasonal population dynamics of free-living and engorged cattle ticks in three agro-ecological zones of the Eastern Cape Province, South Africa
- Authors: Yawa, Mandla
- Date: 2017
- Subjects: Ticks Boophilus microplus
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/9067 , vital:34224
- Description: This study was conducted to determine species composition and seasonal population dynamics of free-living and engorged cattle ticks in three agro-ecological zones (Bedford dry grassland, Kowie thicket and Bisho thornveld) of the Eastern Cape Province, South Africa. The occurrence of ticks on cattle was studied monthly from April 2016 and March 2017. Tick collections were performed on 360 selected cattle in each agro-ecological zones. During tick collections, 10 randomly selected cattle were sampled at each locality and more attention was given to African blue tick and the presence of Asian blue tick. A half body tick collection was performed from cattle and visible ticks were collected by means of fine-forceps after the animals had been restrained. Body regions that were examined includes the ear, head, neck, chest, abdomen, flank, front and hind leg and feet, tail, and peri-anal region. At each locality, six replicate drags of 100 m, approximately 50 m apart, were performed to collect ticks from vegetation. All ticks collected per cattle and from vegetation were stored in labelled sample tubes containing 70percent ethanol, subsequently counted and identified to genus and species level using a standard stereomicroscope. A total of 31425 ticks belonging to ten species were collected during the study. Rhipicephalus (Boophilus) decoloratus, was the most observed tick species (32.50percent), all other ticks like R. evertsi evertsi (18.84percent), R. appendiculatus (17.26percent), A. hebraeum (16.27percent), R. simus (7.69percent) were also commonly collected. Ixodes pilosus (3.84percent), H. rufipes (3.46percent), R. follis (0.08percent) together with Haemaphysalis silacea (0.02percent) were sporadic infestation. Haemaphysalis elliptica (0.04percent) was only found on the vegetation. No H. rufipes was collected in the thicket vegetation. Agro-ecological zones differ significantly (P<0.05) in tick species and distribution. Significantly more R. (B.) decoloratus were collected in thicket during summer compared to thornveld and dry grassland regions (P<0.05). Free-living ticks were widely distributed across different seasons but with of R. (B.) decoloratus larvae were significantly higher (P<0.05) in thornveld region during the spring season. In conclusion, agro-ecological differences and seasonal variations had an influence on ticks abundance and distribution. From this study, it is of interest to note the absence of R. (B.) microplus, whose trend to invade new areas previously colonised by R. (B.) decoloratus has been observed in Africa. In conclusion, agro-ecological differences and seasonal variations had an influence on ticks abundance and distribution. The aforementioned absence of R. (B.) microplus in this study highlights the importance of further research as this tick invades new areas previously colonised by R. (B.) decoloratus in the continent.
- Full Text:
- Authors: Yawa, Mandla
- Date: 2017
- Subjects: Ticks Boophilus microplus
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/9067 , vital:34224
- Description: This study was conducted to determine species composition and seasonal population dynamics of free-living and engorged cattle ticks in three agro-ecological zones (Bedford dry grassland, Kowie thicket and Bisho thornveld) of the Eastern Cape Province, South Africa. The occurrence of ticks on cattle was studied monthly from April 2016 and March 2017. Tick collections were performed on 360 selected cattle in each agro-ecological zones. During tick collections, 10 randomly selected cattle were sampled at each locality and more attention was given to African blue tick and the presence of Asian blue tick. A half body tick collection was performed from cattle and visible ticks were collected by means of fine-forceps after the animals had been restrained. Body regions that were examined includes the ear, head, neck, chest, abdomen, flank, front and hind leg and feet, tail, and peri-anal region. At each locality, six replicate drags of 100 m, approximately 50 m apart, were performed to collect ticks from vegetation. All ticks collected per cattle and from vegetation were stored in labelled sample tubes containing 70percent ethanol, subsequently counted and identified to genus and species level using a standard stereomicroscope. A total of 31425 ticks belonging to ten species were collected during the study. Rhipicephalus (Boophilus) decoloratus, was the most observed tick species (32.50percent), all other ticks like R. evertsi evertsi (18.84percent), R. appendiculatus (17.26percent), A. hebraeum (16.27percent), R. simus (7.69percent) were also commonly collected. Ixodes pilosus (3.84percent), H. rufipes (3.46percent), R. follis (0.08percent) together with Haemaphysalis silacea (0.02percent) were sporadic infestation. Haemaphysalis elliptica (0.04percent) was only found on the vegetation. No H. rufipes was collected in the thicket vegetation. Agro-ecological zones differ significantly (P<0.05) in tick species and distribution. Significantly more R. (B.) decoloratus were collected in thicket during summer compared to thornveld and dry grassland regions (P<0.05). Free-living ticks were widely distributed across different seasons but with of R. (B.) decoloratus larvae were significantly higher (P<0.05) in thornveld region during the spring season. In conclusion, agro-ecological differences and seasonal variations had an influence on ticks abundance and distribution. From this study, it is of interest to note the absence of R. (B.) microplus, whose trend to invade new areas previously colonised by R. (B.) decoloratus has been observed in Africa. In conclusion, agro-ecological differences and seasonal variations had an influence on ticks abundance and distribution. The aforementioned absence of R. (B.) microplus in this study highlights the importance of further research as this tick invades new areas previously colonised by R. (B.) decoloratus in the continent.
- Full Text:
Statistical analysis and modelling of malaria relapse risk factors using Cox Proportional Hazards model approach : a case study of material data collected from Democratic Republic of Congo
- Authors: Mutambayi, Ruffin Mpiana
- Date: 2017
- Subjects: Malaria -- Congo (Democratic Republic) -- Mathematical models Statistics -- Congo (Democratic Republic) -- Econometric models
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15001 , vital:40110
- Description: The field of survival analysis has experienced tremendous growth during the latter half of the 20th century. The objective of this study was to model the relapsing time of uncomplicated falciparum malaria using biographical, sanitation, environmental and preventive information as covariate risk factors. The methodological developments of survival analysis that have had the most profound impact are the Kaplan-Meier method for estimating the survival function, the log-rank test for comparing the equality of two or more survival distributions, and the Cox proportional hazards (PH) model for examining the covariate effects on the hazard function. This thesis presents basic concepts, nonparametric methods (the Kaplan-Meier method and the log-rank test), semi parametric methods (the Cox PH model, and Cox model with time-dependent covariates) and parametric methods (Parametric PH model and the AFT model) for analysing survival data. An improved method was applied to randomized uncomplicated falciparum malaria patients to investigate the risk factors related to the relapsing time in RD Congo. Firstly, the Cox PH model , inf 1 0 ( ) ( )exp 1.91613 0.49633 0.81466 dump spr t X h h t X X X where is the instantaneous risk of experiencing the event at time , without the influence of any covariate was found to better fit the data, as confirmed by the results of the global test that present reasonable and significant results: (Likelihood Ratio: 18.2264 with p-value < 0.0004; Score: 17.6569 with p-value < 0.0005 and Wald: 19.3975 with p<0.0002). Hence from the model above, it can be noticed that ‘dumping site’ (p-value <0.0106; 95percent HR C.I: 1.545, 29.451), ‘spray used’ (p-value < 0. 0.0220; 95percent C.I: 0.391, 0.915), and ‘information related to source of malaria’ (p-value < 0. 0.0012; 95percent C.I: 1.380, 3.725), have a significant impact on the relapsing time of the patients under investigation. It should be noted that many 0() h tt other important covariates such as “usage of mosquito nets” were excluded because of the non-proportionality of the hazards. Secondly, the improvement concept was applied to the Cox model as proposed, and the improved model was as follows: h h t t X t X t X t X t X t X t X t r dump_inf1 spr_inf1 Where h0 (t) is the instantaneous risk of experiencing the event at time t , without the influence of any covariate. The model was found to better fit the data than the standard model — as confirmed by the results from the convergence criterion comparison, where the AIC value of the improved model (754.460) was lower than that of the standard model (767.428). Moreover, the improved model was found to be adequate as the results from the global null hypothesis were significant: (Likelihood Ratio: p-value is 0.0001; Score: p-value is 0.0001; Wald: p-value is 0.0001) and the goodness-of-fit test was confirmed by the plotting of Coxresiduals where the 45 degrees’ line confirmed the results. In conclusion, it was found that the covariates ‘pit’ (p-value is 0.0009; 95percent HR C.I: 11.4133, 1.243e+04), ‘tdwel_spr’ (pvalue = 0.0257; 95percent HR C.I: 1.0016, 1.030e+00), ‘tdwel_inf1 (p-value = 0.0122; 95percent HR C.I: 0.9691, 9.964e-01), ‘maint_dump’ (p-value is 0.0005; 95percent HR C.I: 1.0239, 1.087e+00),‘maint_pit’ (p-value is 0.0007; 95percent HR C.I: 0.9179, 9.774e-01), ‘dump_spr’ (p-value is 0.0027; 95percent HR C.I: 0.9308, 9.853e-01), ‘dump_inf1’ (p-value <0.0001; 95percent HR C.I: 0.9849, 9.947e-01) and ‘spr_inf1’ (p-value is 0.0005; 95percent HR C.I: 1.0119, 1.043e+00) affected the time to relapse from uncomplicated falciparum malaria.
- Full Text:
- Authors: Mutambayi, Ruffin Mpiana
- Date: 2017
- Subjects: Malaria -- Congo (Democratic Republic) -- Mathematical models Statistics -- Congo (Democratic Republic) -- Econometric models
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15001 , vital:40110
- Description: The field of survival analysis has experienced tremendous growth during the latter half of the 20th century. The objective of this study was to model the relapsing time of uncomplicated falciparum malaria using biographical, sanitation, environmental and preventive information as covariate risk factors. The methodological developments of survival analysis that have had the most profound impact are the Kaplan-Meier method for estimating the survival function, the log-rank test for comparing the equality of two or more survival distributions, and the Cox proportional hazards (PH) model for examining the covariate effects on the hazard function. This thesis presents basic concepts, nonparametric methods (the Kaplan-Meier method and the log-rank test), semi parametric methods (the Cox PH model, and Cox model with time-dependent covariates) and parametric methods (Parametric PH model and the AFT model) for analysing survival data. An improved method was applied to randomized uncomplicated falciparum malaria patients to investigate the risk factors related to the relapsing time in RD Congo. Firstly, the Cox PH model , inf 1 0 ( ) ( )exp 1.91613 0.49633 0.81466 dump spr t X h h t X X X where is the instantaneous risk of experiencing the event at time , without the influence of any covariate was found to better fit the data, as confirmed by the results of the global test that present reasonable and significant results: (Likelihood Ratio: 18.2264 with p-value < 0.0004; Score: 17.6569 with p-value < 0.0005 and Wald: 19.3975 with p<0.0002). Hence from the model above, it can be noticed that ‘dumping site’ (p-value <0.0106; 95percent HR C.I: 1.545, 29.451), ‘spray used’ (p-value < 0. 0.0220; 95percent C.I: 0.391, 0.915), and ‘information related to source of malaria’ (p-value < 0. 0.0012; 95percent C.I: 1.380, 3.725), have a significant impact on the relapsing time of the patients under investigation. It should be noted that many 0() h tt other important covariates such as “usage of mosquito nets” were excluded because of the non-proportionality of the hazards. Secondly, the improvement concept was applied to the Cox model as proposed, and the improved model was as follows: h h t t X t X t X t X t X t X t X t r dump_inf1 spr_inf1 Where h0 (t) is the instantaneous risk of experiencing the event at time t , without the influence of any covariate. The model was found to better fit the data than the standard model — as confirmed by the results from the convergence criterion comparison, where the AIC value of the improved model (754.460) was lower than that of the standard model (767.428). Moreover, the improved model was found to be adequate as the results from the global null hypothesis were significant: (Likelihood Ratio: p-value is 0.0001; Score: p-value is 0.0001; Wald: p-value is 0.0001) and the goodness-of-fit test was confirmed by the plotting of Coxresiduals where the 45 degrees’ line confirmed the results. In conclusion, it was found that the covariates ‘pit’ (p-value is 0.0009; 95percent HR C.I: 11.4133, 1.243e+04), ‘tdwel_spr’ (pvalue = 0.0257; 95percent HR C.I: 1.0016, 1.030e+00), ‘tdwel_inf1 (p-value = 0.0122; 95percent HR C.I: 0.9691, 9.964e-01), ‘maint_dump’ (p-value is 0.0005; 95percent HR C.I: 1.0239, 1.087e+00),‘maint_pit’ (p-value is 0.0007; 95percent HR C.I: 0.9179, 9.774e-01), ‘dump_spr’ (p-value is 0.0027; 95percent HR C.I: 0.9308, 9.853e-01), ‘dump_inf1’ (p-value <0.0001; 95percent HR C.I: 0.9849, 9.947e-01) and ‘spr_inf1’ (p-value is 0.0005; 95percent HR C.I: 1.0119, 1.043e+00) affected the time to relapse from uncomplicated falciparum malaria.
- Full Text:
Stem cutting propagation protocol for rose-scented geranium (Pelargonium graveolens)
- Authors: Matafeni, Ntombekhaya
- Date: 2017
- Subjects: Plant propagation Pelargoniums Plant cuttings
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/9832 , vital:35060
- Description: Rose-scented geranium (Pelargonium graveolens), is a high value essential oil plant that is used in the perfumery, cosmetic, aromatherapy and food flavouring industries. The increasing demand for this plant, due to its economic importance necessitates the development of an efficient propagation protocol for quality seedling and its maximum production. The present study therefore, sought to develop effective stem cutting propagation protocol which could facilitate multiplication of rose-scented geranium stem cuttings. Three separate experiments were undertaken to determine factors influencing effective propagation of rose-scented geranium. These factors were: rooting media, rooting hormone, cutting length and wound healing period on rooting and development of rose-scented geranium stem cuttings. The cuttings were assessed based on root number, length and fresh mass, plant height, leaf number, and stem circumference. In terms of root measurements, the growing media were washed out from the root system of plantlets, their roots were separated from stem before data was recorded which comprised of root number, length and root fresh mass. Root holding ability (RHA) on rooting medium was determined by visual observation and rated on a 1-5 scale where 1 = very loose, not acceptable; 2 = loose, not acceptable; 3 = medium, marginally acceptable; 4 = tight, acceptable; 5 = very tight, acceptable. The experiments were carried out at Essential Amatole Nursery, at the University of Fort Hare Research Farm, Alice Campus (located at 320 47ʹ3ʺS, 260 50ʹ43ʺ E, with an altitude of 519 m.a.s.l). All the experiments were carried out under mist conditions on bottom-heated beds in a greenhouse (with polycarbonate roofing of about 40percent shading effect) for the first three weeks after sticking the cuttings to the growing medium to facilitate root induction in relatively high temperature and relative humidity. Thereafter, the plantlets were grown in a shade house with 70percent light penetration until the termination of the experiment. To optimize the technology for the propagation of this plant the present experiment was designed with the objective to determine the efficient growing medium and proper rooting hormone for successful rooting and development of quality seedlings of rose-scented geranium. The experiment was set up in a complete randomized design (CRD) and was replicated three times with two factors 7×4, seven different growing media i.e. (1) Mixture growing medium which serves as control (pine bark 8 bags + sand 2 bags + lime 4kg + coconut 10 blocks + talborne 6.25 kg + bone meal 2 kg); (2) River sand only; (3) Pine bark; (4) Hygrotex (commercial rooting media); (5) Pine bark + river sand ( at1:1 ratio on volume basis); (6) Pine bark + hygrotex (at 1:1, ratio on volume basis), and; (7) Pine bark + river sand + hygrotex ( at 1:1:1 ratio on volume basis) and four different IBA hormone levels (auxins, types of IBA) applied as treatment were (1) Dynaroot (1 – 1g/kg), (2) Dynaroot (2- 3g/kg), (3) Dynaroot (3-8g/kg) and (4) Control (untreated with hormone). Hygrotex was identified as the best growth media for quicker regeneration giving the highest root number, length and fresh mass. While, hygrotex + pine bark (v/v 1:1) was efficient in producing more leaves, stem circumference and other aerial parameters. Dynaroot 3 was identified as the best rooting enhancer with maximum root number, length, fresh weight and plant height. Both Dynaroot 3 and Dynaroot 2 did not have major differences on giving highest leaf number. Control (untreated with hormone) was consistent in giving the greatest stem circumference than any other treatment. To maximize stem circumference, a combination of control (untreated with hormone) and hygrotex + pine bark (v/v 1:1) was identified as the best treatment. Based on the investigation for maximum production and quality seedlings of rose-scented geranium, hygrotex and Dynaroot 3 were identified as the best combination for successful rooting. The ideal cutting stem length, rooting hormone and growing medium for quality seedlings of rose-scented geranium were also investigated. The experimental lay out was in randomized complete design (RCD) with a 4 × 4 × 2 factorial treatment combination. Treatments used were, four different cutting lengths viz. 10, 12, 14 and 16 cm long; four different concentrations of IBA rooting hormone (Dynaroot 1, 2, 3 (powder form) and distilled water (control) and two types of growing medium (hygrotex and hygrotex + pine bark v/v 1:1) were used. Stem cuttings of 14 and 16 cm length gave the highest root number of 34, 38 and 35.13, and root length of 3.40 and 3.51cm respectively, with no significance. Cutting length of 10 cm favoured stem circumference (3.1 cm) as compared to other treatments. Whereas, cuttings treated with Dynaroot 3 showed a better root number (33.46 roots), root length (3.54 cm), root fresh mass (0.59 mg), leaf number of (11.08) as well as highest root holding ability (5). However, they showed no significance difference with Dynaroot 2 treated cuttings. In addition, cuttings treated with Control favoured shoot number (3.79) and stem circumference (3.05). Visually, hygrotex was observed to be better substrate though it was not significantly different from hygrotex + pine bark (1:1 v/v) on propagation of rose-scented geranium stem cuttings. Therefore, it is recommended that rose-scented geranium should be propagated through the combination of 14 cm cuttings length and treated with Dynaroot 2 IBA rooting hormone. Both hygrotex and hygrotex + pine bark (1:1 v/v) are the best growing media for root formation and growth of rose-scented geranium, though hygrotex alone is more economical. Wound healing period (WHP) of stem cutting was evaluated using 4 × 4 factorial, cuttings were separated into four groups during the healing duration (intervals of 24 hrs: days 0, 1, 2 and 3). These four groups were further subdivided into four subgroups of rooting hormone viz. Dynaroot 1, 2, 3 of indole-3-butyric acid and control (water). Experiment was laid out in a randomised complete block design (RCBD) with three replicates. The results obtained from the study revealed that rose-scented geranium rooted easily when planted on Day 2 of the wound healing period such that root holding ability was at its highest. While, Day 0 cuttings showed good response for stem circumference and shoot number. The study recommends that rose-scented geranium be propagated using cuttings that have enough time to heal the wound that is, Day 2 cuttings. Dynaroot 3 (IBA hormone concentration) showed good response to rooting and other arial parameters except for stem circumference which was favoured by application of control. Based on the results of the study, it can be concluded that propagation of rose-scented geranium requires a wound healing period of about three days in room temperature and application of IBA hormone before sucking cuttings in growing medium. Instead, of Dynaroot 3 or 2, Dynaroot 1 can also be used because, it is less economical and they all have a similar effect on cuttings that have been healing for three days.
- Full Text:
- Authors: Matafeni, Ntombekhaya
- Date: 2017
- Subjects: Plant propagation Pelargoniums Plant cuttings
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/9832 , vital:35060
- Description: Rose-scented geranium (Pelargonium graveolens), is a high value essential oil plant that is used in the perfumery, cosmetic, aromatherapy and food flavouring industries. The increasing demand for this plant, due to its economic importance necessitates the development of an efficient propagation protocol for quality seedling and its maximum production. The present study therefore, sought to develop effective stem cutting propagation protocol which could facilitate multiplication of rose-scented geranium stem cuttings. Three separate experiments were undertaken to determine factors influencing effective propagation of rose-scented geranium. These factors were: rooting media, rooting hormone, cutting length and wound healing period on rooting and development of rose-scented geranium stem cuttings. The cuttings were assessed based on root number, length and fresh mass, plant height, leaf number, and stem circumference. In terms of root measurements, the growing media were washed out from the root system of plantlets, their roots were separated from stem before data was recorded which comprised of root number, length and root fresh mass. Root holding ability (RHA) on rooting medium was determined by visual observation and rated on a 1-5 scale where 1 = very loose, not acceptable; 2 = loose, not acceptable; 3 = medium, marginally acceptable; 4 = tight, acceptable; 5 = very tight, acceptable. The experiments were carried out at Essential Amatole Nursery, at the University of Fort Hare Research Farm, Alice Campus (located at 320 47ʹ3ʺS, 260 50ʹ43ʺ E, with an altitude of 519 m.a.s.l). All the experiments were carried out under mist conditions on bottom-heated beds in a greenhouse (with polycarbonate roofing of about 40percent shading effect) for the first three weeks after sticking the cuttings to the growing medium to facilitate root induction in relatively high temperature and relative humidity. Thereafter, the plantlets were grown in a shade house with 70percent light penetration until the termination of the experiment. To optimize the technology for the propagation of this plant the present experiment was designed with the objective to determine the efficient growing medium and proper rooting hormone for successful rooting and development of quality seedlings of rose-scented geranium. The experiment was set up in a complete randomized design (CRD) and was replicated three times with two factors 7×4, seven different growing media i.e. (1) Mixture growing medium which serves as control (pine bark 8 bags + sand 2 bags + lime 4kg + coconut 10 blocks + talborne 6.25 kg + bone meal 2 kg); (2) River sand only; (3) Pine bark; (4) Hygrotex (commercial rooting media); (5) Pine bark + river sand ( at1:1 ratio on volume basis); (6) Pine bark + hygrotex (at 1:1, ratio on volume basis), and; (7) Pine bark + river sand + hygrotex ( at 1:1:1 ratio on volume basis) and four different IBA hormone levels (auxins, types of IBA) applied as treatment were (1) Dynaroot (1 – 1g/kg), (2) Dynaroot (2- 3g/kg), (3) Dynaroot (3-8g/kg) and (4) Control (untreated with hormone). Hygrotex was identified as the best growth media for quicker regeneration giving the highest root number, length and fresh mass. While, hygrotex + pine bark (v/v 1:1) was efficient in producing more leaves, stem circumference and other aerial parameters. Dynaroot 3 was identified as the best rooting enhancer with maximum root number, length, fresh weight and plant height. Both Dynaroot 3 and Dynaroot 2 did not have major differences on giving highest leaf number. Control (untreated with hormone) was consistent in giving the greatest stem circumference than any other treatment. To maximize stem circumference, a combination of control (untreated with hormone) and hygrotex + pine bark (v/v 1:1) was identified as the best treatment. Based on the investigation for maximum production and quality seedlings of rose-scented geranium, hygrotex and Dynaroot 3 were identified as the best combination for successful rooting. The ideal cutting stem length, rooting hormone and growing medium for quality seedlings of rose-scented geranium were also investigated. The experimental lay out was in randomized complete design (RCD) with a 4 × 4 × 2 factorial treatment combination. Treatments used were, four different cutting lengths viz. 10, 12, 14 and 16 cm long; four different concentrations of IBA rooting hormone (Dynaroot 1, 2, 3 (powder form) and distilled water (control) and two types of growing medium (hygrotex and hygrotex + pine bark v/v 1:1) were used. Stem cuttings of 14 and 16 cm length gave the highest root number of 34, 38 and 35.13, and root length of 3.40 and 3.51cm respectively, with no significance. Cutting length of 10 cm favoured stem circumference (3.1 cm) as compared to other treatments. Whereas, cuttings treated with Dynaroot 3 showed a better root number (33.46 roots), root length (3.54 cm), root fresh mass (0.59 mg), leaf number of (11.08) as well as highest root holding ability (5). However, they showed no significance difference with Dynaroot 2 treated cuttings. In addition, cuttings treated with Control favoured shoot number (3.79) and stem circumference (3.05). Visually, hygrotex was observed to be better substrate though it was not significantly different from hygrotex + pine bark (1:1 v/v) on propagation of rose-scented geranium stem cuttings. Therefore, it is recommended that rose-scented geranium should be propagated through the combination of 14 cm cuttings length and treated with Dynaroot 2 IBA rooting hormone. Both hygrotex and hygrotex + pine bark (1:1 v/v) are the best growing media for root formation and growth of rose-scented geranium, though hygrotex alone is more economical. Wound healing period (WHP) of stem cutting was evaluated using 4 × 4 factorial, cuttings were separated into four groups during the healing duration (intervals of 24 hrs: days 0, 1, 2 and 3). These four groups were further subdivided into four subgroups of rooting hormone viz. Dynaroot 1, 2, 3 of indole-3-butyric acid and control (water). Experiment was laid out in a randomised complete block design (RCBD) with three replicates. The results obtained from the study revealed that rose-scented geranium rooted easily when planted on Day 2 of the wound healing period such that root holding ability was at its highest. While, Day 0 cuttings showed good response for stem circumference and shoot number. The study recommends that rose-scented geranium be propagated using cuttings that have enough time to heal the wound that is, Day 2 cuttings. Dynaroot 3 (IBA hormone concentration) showed good response to rooting and other arial parameters except for stem circumference which was favoured by application of control. Based on the results of the study, it can be concluded that propagation of rose-scented geranium requires a wound healing period of about three days in room temperature and application of IBA hormone before sucking cuttings in growing medium. Instead, of Dynaroot 3 or 2, Dynaroot 1 can also be used because, it is less economical and they all have a similar effect on cuttings that have been healing for three days.
- Full Text:
Strategies used to cater for students with diverse academic backgrounds in the provision of textile, clothing and design programmes: a case study of two universities of technology in Zimbabwe
- Authors: Chimbindi, Felisia
- Date: 2017
- Subjects: Multicultural education -- Zimbabwe -- Cross-cultural studies Inclusive education -- Zimbabwe -- Cross-cultural studies
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/4948 , vital:28871
- Description: Universities admit students from diverse backgrounds and have an obligation to accommodate all the students in various educational programmes to ensure that they acquire relevant skills and knowledge. The provision of Textile, Clothing and Design programmes to students with diverse academic backgrounds in universities of technology in Zimbabwe has led to various concerns raised by the textile and clothing stakeholders. The concerns include poor performance of students, high student failure rate, high student drop out, late completion of programmes by students, and other problems emanating from curriculum implementation approaches used by the lecturers. This study therefore, sought to find out how students with diverse academic backgrounds are catered for in the provision of TCD programmes in the two sampled universities of technology in Zimbabwe, with a view to assist the students and to enhance the quality of TCD provision. The study adopted a post-positivism paradigm and used a mixed method research approach that integrated concurrent qualitative and quantitative procedures in data collection, analysis and interpretation. A questionnaire, interviews and document analysis were used to collect data from respondents. Purposive sampling procedure was used to select 36 TCD lecturers, 2 universities’ quality assurance directors, 2 TCD faculty deans of studies, and 2 department chairpersons. Collected data were analyzed using statistical and non-statistical procedures. The study revealed that catering for students with diverse academic backgrounds was practiced in the two universities despite the absence of a curriculum implementation policy to guide the provision of TCD programmes to students with diverse academic backgrounds at university level. It emerged that catering for students with diverse academic backgrounds in implementing TCD curricular at the two sampled universities was faced with various challenges that include lack of lecturer training with regard to catering for students from diverse academic backgrounds and inadequate lecturer training in depth TCD subject content knowledge and ICT teaching technology packages. The study also revealed that there is not enough university and stakeholder participation with regards to supporting and monitoring curriculum implementation process to cater for students with diverse academic backgrounds. Although there were challenges encountered in catering for students with diverse academic backgrounds, the study reveals that there are pockets of good practice in some curriculum implementation strategies implemented by the two institutions such as use of student centered teaching and instructional approaches, university support and lecturer commitment to assist the students. The study findings conclude that although catering for TCD students with diverse academic backgrounds was being practiced in the two universities of technology, there are very critical issues observed over the programmes implementation process that include absence of curriculum implementation policy, lack of training of lecturers and inadequate participative TCD stakeholder involvement. Based on the study findings and reviewed literature, the researcher suggests an alternative curriculum implementation framework for catering for students with diverse academic backgrounds that may help improve effectiveness of university programmes implementation.
- Full Text:
- Authors: Chimbindi, Felisia
- Date: 2017
- Subjects: Multicultural education -- Zimbabwe -- Cross-cultural studies Inclusive education -- Zimbabwe -- Cross-cultural studies
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/4948 , vital:28871
- Description: Universities admit students from diverse backgrounds and have an obligation to accommodate all the students in various educational programmes to ensure that they acquire relevant skills and knowledge. The provision of Textile, Clothing and Design programmes to students with diverse academic backgrounds in universities of technology in Zimbabwe has led to various concerns raised by the textile and clothing stakeholders. The concerns include poor performance of students, high student failure rate, high student drop out, late completion of programmes by students, and other problems emanating from curriculum implementation approaches used by the lecturers. This study therefore, sought to find out how students with diverse academic backgrounds are catered for in the provision of TCD programmes in the two sampled universities of technology in Zimbabwe, with a view to assist the students and to enhance the quality of TCD provision. The study adopted a post-positivism paradigm and used a mixed method research approach that integrated concurrent qualitative and quantitative procedures in data collection, analysis and interpretation. A questionnaire, interviews and document analysis were used to collect data from respondents. Purposive sampling procedure was used to select 36 TCD lecturers, 2 universities’ quality assurance directors, 2 TCD faculty deans of studies, and 2 department chairpersons. Collected data were analyzed using statistical and non-statistical procedures. The study revealed that catering for students with diverse academic backgrounds was practiced in the two universities despite the absence of a curriculum implementation policy to guide the provision of TCD programmes to students with diverse academic backgrounds at university level. It emerged that catering for students with diverse academic backgrounds in implementing TCD curricular at the two sampled universities was faced with various challenges that include lack of lecturer training with regard to catering for students from diverse academic backgrounds and inadequate lecturer training in depth TCD subject content knowledge and ICT teaching technology packages. The study also revealed that there is not enough university and stakeholder participation with regards to supporting and monitoring curriculum implementation process to cater for students with diverse academic backgrounds. Although there were challenges encountered in catering for students with diverse academic backgrounds, the study reveals that there are pockets of good practice in some curriculum implementation strategies implemented by the two institutions such as use of student centered teaching and instructional approaches, university support and lecturer commitment to assist the students. The study findings conclude that although catering for TCD students with diverse academic backgrounds was being practiced in the two universities of technology, there are very critical issues observed over the programmes implementation process that include absence of curriculum implementation policy, lack of training of lecturers and inadequate participative TCD stakeholder involvement. Based on the study findings and reviewed literature, the researcher suggests an alternative curriculum implementation framework for catering for students with diverse academic backgrounds that may help improve effectiveness of university programmes implementation.
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Strategies, challenges and socio-economic contribution of immigrant entrepreneurship in the Buffalo City Metropolitan Municipal Area
- Authors: Muridzo, Phillemon Dudzai
- Date: 2017
- Subjects: Minority business enterprises -- South Africa Entrepreneurship -- South Africa
- Language: English
- Type: Thesis , Masters , MSoc
- Identifier: http://hdl.handle.net/10353/17849 , vital:41375
- Description: Immigrants, in whatever country they settle, have always been involved in entrepreneurial activities mainly for survival, remittance and other purposes. Globally, immigrant entrepreneurship has significantly contributed to the economy of host nations. The aim of this research study is to investigate the business strategies, challenges and socio-economic contribution of immigrant entrepreneurship in the Buffalo City Metropolitan Municipal (BCMM) area, Eastern Cape, South Africa. This study builds upon fieldwork undertaken within the Buffalo City Metropolitan Municipal area situated in the Eastern Cape Province of South Africa. A Case Study research design was utilised, and it encompassed three kinds of data collection methods – indepth interviews, focus groups and direct observation. The key finding of this study indicated that as a consequence of the challenges they encounter, immigrant entrepreneurs in the Buffalo City Metropolitan Municipal area had devised different business strategies to ensure that their businesses remain afloat and profitable. Another key finding of the study is that immigrant entrepreneurs in the BCMM Area make significant socio-economic contributions to their host communities. In addition to other positive contributions, immigrant entrepreneurs add to the revitalization of neighbourhoods and provide employment to their respective communities.
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- Authors: Muridzo, Phillemon Dudzai
- Date: 2017
- Subjects: Minority business enterprises -- South Africa Entrepreneurship -- South Africa
- Language: English
- Type: Thesis , Masters , MSoc
- Identifier: http://hdl.handle.net/10353/17849 , vital:41375
- Description: Immigrants, in whatever country they settle, have always been involved in entrepreneurial activities mainly for survival, remittance and other purposes. Globally, immigrant entrepreneurship has significantly contributed to the economy of host nations. The aim of this research study is to investigate the business strategies, challenges and socio-economic contribution of immigrant entrepreneurship in the Buffalo City Metropolitan Municipal (BCMM) area, Eastern Cape, South Africa. This study builds upon fieldwork undertaken within the Buffalo City Metropolitan Municipal area situated in the Eastern Cape Province of South Africa. A Case Study research design was utilised, and it encompassed three kinds of data collection methods – indepth interviews, focus groups and direct observation. The key finding of this study indicated that as a consequence of the challenges they encounter, immigrant entrepreneurs in the Buffalo City Metropolitan Municipal area had devised different business strategies to ensure that their businesses remain afloat and profitable. Another key finding of the study is that immigrant entrepreneurs in the BCMM Area make significant socio-economic contributions to their host communities. In addition to other positive contributions, immigrant entrepreneurs add to the revitalization of neighbourhoods and provide employment to their respective communities.
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Synthesis and characterization of CdSe quantum dots for solar cell application
- Authors: Makinana, Sinovuyo
- Date: 2017
- Subjects: Quantum dots Quantum dots -- Optical properties Renewable energy sources
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/5994 , vital:29466
- Description: This study shows a detailed report on the morphological, structural and optical properties of CdSe QDs synthesised by the hot injection method. Cadmium acetate dihydrate and Se powder were used as cadmium and selenide precursors, respectively. Various QD sizes were achieved by synthesizing in temperature range of 150ºC, 175ºC, 200ºC, 225ºC, 250ºC, 275ºC and 300ºC, respectively. The as synthesized QDs by the hot injection method were cross-examined for their morphological, structural and optical using HRTEM, FTIR, XRD, RS, and UV-Vis spectroscopy techniques respectively. FTIR analysis has revealed vibrations at 738, 738, 738, 738, 735, 735 and 733 cm-1 for the QDs synthesized at various temperatures of 150, 175, 200, 225, 250, 275, and 300℃, respectively. The presence of the above mentioned peaks confirms the presence of Cd-Se bond in our samples. XRD analysis of CdSe QDs revealed diffraction peaks at 2 angles of 16.66 , 25.20 , 34.77 , 40.9 , 45.39 and 49.1 for 150 17.4 , 25.22 , 34.85 , 41.7 , 44.45 and 47.5 for the QDs synthesized at various temperatures of 175 17.07 , 25.19 , 34.85 , 41.34 , 44.41 and 48.86 for 200 ; 16.34 , 25.20 , 34.76 , 40.6 , 44.74 and 49.48 for 225 ; 17.44 , 25.17 , 34.19 , 41.7 , 44.45 , 49.24 for 250 ; 16.70 , 25.16 , 34.85 , 40.32 , 45.1 and 49.1 7 for 275 ;and 17.35 , 25.18 , 35.13 , 41.63 , 45.7 , 49.48 for 300 . These XRD peaks relate to crystal planes of (100), (002), (102), (220), (103) and (112) which belong to hexagonal Wurtzite CdSe crystal structure. Additionally XRD analysis has revealed a general peak shift to higher 2 values was observed for CdSe QDs. HRTEM analysis showed that the synthesised CdSe QDs have a spherical shape and are monodispersed. Moreover, HRTEM analysis has revealed CdSe QDs modal crystallite size of 1.79 nm, 1.81 nm, 2.06 nm, 2.08 nm, 2.11 nm, 3.10 nm and 3.12 nm for the QDs synthesized at various temperatures of 150ºC, 175ºC, 200ºC, 225ºC, 250ºC, 275ºC and 300ºC, respectively. HRTEM results were in mutual agreement with XRD results. Additionally, the SAED images showed intense electron diffraction rings, which confirmed that the as-synthesised CdSe QDs have a Wurtzite crystal structure. RS analysis showed that CdSe QDs have LO and 2LO vibrational modes which are characteristic peaks for CdSe. The presence of these peaks in Raman spectra further supports our previous observation from XRD analysis and HRTEM analysis that the synthesized CdSe QDs have a Wurtzite crystal structure. The effect of synthesis temperature Raman peak shift, FHWH and peak intensity has been cross examined in this work, Moreover, the effect of increasing temperature on the peak shift, FWHM and peak intensity is discussed in detail below. UV-Vis analysis revealed an absorbance of CdSe QDs in higher wavelengths as temperature was increased. Furthermore, the Yu et al 2003 relation was used to calculate QD size and band gap energy of CdSe QDs. The results showed that QD size increases with increasing synthesis temperature, which is in agreement with HRTEM and XRD results.
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- Authors: Makinana, Sinovuyo
- Date: 2017
- Subjects: Quantum dots Quantum dots -- Optical properties Renewable energy sources
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/5994 , vital:29466
- Description: This study shows a detailed report on the morphological, structural and optical properties of CdSe QDs synthesised by the hot injection method. Cadmium acetate dihydrate and Se powder were used as cadmium and selenide precursors, respectively. Various QD sizes were achieved by synthesizing in temperature range of 150ºC, 175ºC, 200ºC, 225ºC, 250ºC, 275ºC and 300ºC, respectively. The as synthesized QDs by the hot injection method were cross-examined for their morphological, structural and optical using HRTEM, FTIR, XRD, RS, and UV-Vis spectroscopy techniques respectively. FTIR analysis has revealed vibrations at 738, 738, 738, 738, 735, 735 and 733 cm-1 for the QDs synthesized at various temperatures of 150, 175, 200, 225, 250, 275, and 300℃, respectively. The presence of the above mentioned peaks confirms the presence of Cd-Se bond in our samples. XRD analysis of CdSe QDs revealed diffraction peaks at 2 angles of 16.66 , 25.20 , 34.77 , 40.9 , 45.39 and 49.1 for 150 17.4 , 25.22 , 34.85 , 41.7 , 44.45 and 47.5 for the QDs synthesized at various temperatures of 175 17.07 , 25.19 , 34.85 , 41.34 , 44.41 and 48.86 for 200 ; 16.34 , 25.20 , 34.76 , 40.6 , 44.74 and 49.48 for 225 ; 17.44 , 25.17 , 34.19 , 41.7 , 44.45 , 49.24 for 250 ; 16.70 , 25.16 , 34.85 , 40.32 , 45.1 and 49.1 7 for 275 ;and 17.35 , 25.18 , 35.13 , 41.63 , 45.7 , 49.48 for 300 . These XRD peaks relate to crystal planes of (100), (002), (102), (220), (103) and (112) which belong to hexagonal Wurtzite CdSe crystal structure. Additionally XRD analysis has revealed a general peak shift to higher 2 values was observed for CdSe QDs. HRTEM analysis showed that the synthesised CdSe QDs have a spherical shape and are monodispersed. Moreover, HRTEM analysis has revealed CdSe QDs modal crystallite size of 1.79 nm, 1.81 nm, 2.06 nm, 2.08 nm, 2.11 nm, 3.10 nm and 3.12 nm for the QDs synthesized at various temperatures of 150ºC, 175ºC, 200ºC, 225ºC, 250ºC, 275ºC and 300ºC, respectively. HRTEM results were in mutual agreement with XRD results. Additionally, the SAED images showed intense electron diffraction rings, which confirmed that the as-synthesised CdSe QDs have a Wurtzite crystal structure. RS analysis showed that CdSe QDs have LO and 2LO vibrational modes which are characteristic peaks for CdSe. The presence of these peaks in Raman spectra further supports our previous observation from XRD analysis and HRTEM analysis that the synthesized CdSe QDs have a Wurtzite crystal structure. The effect of synthesis temperature Raman peak shift, FHWH and peak intensity has been cross examined in this work, Moreover, the effect of increasing temperature on the peak shift, FWHM and peak intensity is discussed in detail below. UV-Vis analysis revealed an absorbance of CdSe QDs in higher wavelengths as temperature was increased. Furthermore, the Yu et al 2003 relation was used to calculate QD size and band gap energy of CdSe QDs. The results showed that QD size increases with increasing synthesis temperature, which is in agreement with HRTEM and XRD results.
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Synthesis and characterization of titanium dioxide nanotubes using electrochemical anodization technique for solar cell applications
- Authors: Lupiwana, Mpheleki
- Date: 2017
- Subjects: Titanium dioxide Nanostructured materials Nanotubes
- Language: English
- Type: Thesis , Masters , Chemistry
- Identifier: http://hdl.handle.net/10353/11795 , vital:39107
- Description: High demand on energy conversion in dye-sensitized solar solar cells (DSSCs), requires development of well-organized TiO2 nanotube (TNT) structures because of their large surface area-to-volume ratio, superior lifetime and provision of optimal pathways for electron percolation. In this work TiO2 nanotube membranes with an average length of 2.40 μm and average pore diameter of 41.08 nm have been fabricated using electrochemical anodisation employing an organic electrolyte consisting of 0.5wt.percent NH4F + 3 vol percent H2O + Glycerol at an applied voltage of 60 V for 12 hours. The fabricated TNTs were annealed at different annealing temperatures. Scanning Electron Microscopy (SEM) showed that anodisation at these conditions yields nanotubes with periodic rings which present the roughness of the walls. Surface SEM images have revealed the presence of porous structures on the fabricated TNT membranes. Also evident from SEM cross-sectional images are multi-layered TiO2 nanotubes with top and bottom layers. The effect of annealing temperature on the structural, morphological and topographical has been investigated for TNTs. Surface SEM morphological analyses have revealed that the surface morphology of the annealed TNTs membranes changes with an increase in annealing temperature from 350°C to 650°C. The surface SEM analysis has revealed that as the annealing temperature increases the fabricated nanotubes deforms and collapses at annealing temperatures above 550°C. The TNTs annealed at 350°C have a modal pore size of 34.56 nm which is somewhat smaller compared to the TNTs annealed at 650°C with a modal pore size of 31.05 nm. Atomic Force Microscopy (AFM) topographical measurements have confirmed the presence of porous structure on the surface of the as-annealed TNTs with a modal pore diameter decreasing with increasing in annealing temperature. SEM-EDS analysis have revealed the presence of Ti, O and C and no other additional impurities. The presence of Ti and O confirms the successful electro-anodization of titanium metal sheets to TNTs. C must be due to glycerol electrolyte that got absorbed onto the TNTs structured during electro anodization. Structure investigation through X-Ray Diffraction (XRD) analysis has revealed that as-anodised TNTs have peaks at 2Ɵ positions 35.62°, 39.02°, 40.76°, 53.55°, 63.49°, 71.14°, and 76.71° belonging to the amorphous phase of TiO2. Additionally XRD analysis has revealed that for the annealed samples in the temperature range from 350°C to 450°C have peaks at 24.66° (101), 27.11° (110) belonging Anatase and Rutile phase of TiO2 respectively. Confocal Raman Spectroscopy (CRM) image analysis through a large area scan, and Raman depth profiling have also been used to evaluate the phase changes in TNTs annealed at different temperatures. CRM large area scan and depth profiling has revealed the presence of Anatase phase of TiO2 with Raman vibration modes at 142.37 cm-1, 199.04 cm-1, 394.67 cm-1,516.16 cm-1 and 639.29 cm-1 and the presence of some Rutile phase of TiO2 peaks with Raman vibration modes at 445.26 cm-1 and 612.07 cm-1. These findings were correlated to the XRD analysis, SEM analysis as well as AFM. In XRD the transformation of Anatase to Rutile phase was observed as the annealing temperature increased, that was also supported by SEM analysis whereby nanotube structures collapsed and deformed as annealing temperature increased due to phase transformation. In AFM pore diameter decreased as annealing temperature increases, which was also due to the effect of phase transformation observed in XRD and CRM. These findings showed that TiO2 nanotube membranes were successfully fabricated, which may have wide applications in the development of electronic materials for the solar devices.
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- Authors: Lupiwana, Mpheleki
- Date: 2017
- Subjects: Titanium dioxide Nanostructured materials Nanotubes
- Language: English
- Type: Thesis , Masters , Chemistry
- Identifier: http://hdl.handle.net/10353/11795 , vital:39107
- Description: High demand on energy conversion in dye-sensitized solar solar cells (DSSCs), requires development of well-organized TiO2 nanotube (TNT) structures because of their large surface area-to-volume ratio, superior lifetime and provision of optimal pathways for electron percolation. In this work TiO2 nanotube membranes with an average length of 2.40 μm and average pore diameter of 41.08 nm have been fabricated using electrochemical anodisation employing an organic electrolyte consisting of 0.5wt.percent NH4F + 3 vol percent H2O + Glycerol at an applied voltage of 60 V for 12 hours. The fabricated TNTs were annealed at different annealing temperatures. Scanning Electron Microscopy (SEM) showed that anodisation at these conditions yields nanotubes with periodic rings which present the roughness of the walls. Surface SEM images have revealed the presence of porous structures on the fabricated TNT membranes. Also evident from SEM cross-sectional images are multi-layered TiO2 nanotubes with top and bottom layers. The effect of annealing temperature on the structural, morphological and topographical has been investigated for TNTs. Surface SEM morphological analyses have revealed that the surface morphology of the annealed TNTs membranes changes with an increase in annealing temperature from 350°C to 650°C. The surface SEM analysis has revealed that as the annealing temperature increases the fabricated nanotubes deforms and collapses at annealing temperatures above 550°C. The TNTs annealed at 350°C have a modal pore size of 34.56 nm which is somewhat smaller compared to the TNTs annealed at 650°C with a modal pore size of 31.05 nm. Atomic Force Microscopy (AFM) topographical measurements have confirmed the presence of porous structure on the surface of the as-annealed TNTs with a modal pore diameter decreasing with increasing in annealing temperature. SEM-EDS analysis have revealed the presence of Ti, O and C and no other additional impurities. The presence of Ti and O confirms the successful electro-anodization of titanium metal sheets to TNTs. C must be due to glycerol electrolyte that got absorbed onto the TNTs structured during electro anodization. Structure investigation through X-Ray Diffraction (XRD) analysis has revealed that as-anodised TNTs have peaks at 2Ɵ positions 35.62°, 39.02°, 40.76°, 53.55°, 63.49°, 71.14°, and 76.71° belonging to the amorphous phase of TiO2. Additionally XRD analysis has revealed that for the annealed samples in the temperature range from 350°C to 450°C have peaks at 24.66° (101), 27.11° (110) belonging Anatase and Rutile phase of TiO2 respectively. Confocal Raman Spectroscopy (CRM) image analysis through a large area scan, and Raman depth profiling have also been used to evaluate the phase changes in TNTs annealed at different temperatures. CRM large area scan and depth profiling has revealed the presence of Anatase phase of TiO2 with Raman vibration modes at 142.37 cm-1, 199.04 cm-1, 394.67 cm-1,516.16 cm-1 and 639.29 cm-1 and the presence of some Rutile phase of TiO2 peaks with Raman vibration modes at 445.26 cm-1 and 612.07 cm-1. These findings were correlated to the XRD analysis, SEM analysis as well as AFM. In XRD the transformation of Anatase to Rutile phase was observed as the annealing temperature increased, that was also supported by SEM analysis whereby nanotube structures collapsed and deformed as annealing temperature increased due to phase transformation. In AFM pore diameter decreased as annealing temperature increases, which was also due to the effect of phase transformation observed in XRD and CRM. These findings showed that TiO2 nanotube membranes were successfully fabricated, which may have wide applications in the development of electronic materials for the solar devices.
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Synthesis of modified zinc oxide nanoparticles using pneumatic spray pyrolysis for solar cell application
- Authors: Ntozakhe, Luyolo
- Date: 2017
- Subjects: Zinc oxide -- Synthesis Nanoparticles
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/5862 , vital:29408
- Description: In this work, the pneumatic spray pyrolysis was used to synthesize un-doped and carbon doped zinc oxide (ZnO) nanoparticles. The zinc acetate, tetrabutylammonium bromide and ethanol were used as starting materials for the desired ZnO nanoparticles and the prepared samples were annealed at 400 oC in the furnace. The as synthesized un-doped and carbon doped ZnO NPs were evaluated using X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy dispersive x-ray spectroscopy (EDX), High-resolution transmission electron microscopy (HRTEM), Raman spectroscopy (RS) and Ultraviolet-visible spectroscopy (UV-Vis). XRD analysis of the synthesized NPs revealed peaks at 31.90°, 34.50°, 36.34°, 47.73°, 56.88°, 63.04°, 68.20°, and 77.33° belonging to the hexagonal Wurtzite ZnO crystal structure. The incorporation of C species into ZnO lattice was cross examined by monitoring the peak positions of the (100), (002) and (001) planes. These three main peaks of C-ZnO NPs show a peak shift to higher 2θ values which indicates substitutional carbon doping in ZnO NPs. SEM analysis has revealed that the as synthesized NPs have spherical shape and the morphology of the NPs change as the concentration of carbon increases. The EDX spectra of both un-doped and doped ZnO nanoparticles have revealed prominent peaks at 0.51 keV, 1.01 keV, 1.49 keV, 8.87 keV and 9.86 keV. Peaks at, X-ray energies of 0.51 keV and 1.01 keV respectively represent the emissions from the K-shell of oxygen and L-shell of zinc. The L-shell emission at 1.01 keV is considered as convolution of Zn 2p3/2 and Zn 2p1/2 photoelectron energies. The occurrence of these peaks in the EDX endorses the existence of Zn and O atoms in the PSP prepared samples. HRTEM analysis has revealed NPs size modal range from 6.65-14.21 nm for the PSP synthesized samples which is in mutual agreement with the XRD data calculated values. More over the selected area diffraction images displaying the fact that only the diffraction planes of (101), (002) and (100) are responsible for the diffraction pattern belonging to Wurtzite ZnO. RS analysis has revealed that the un-doped ZnO and doped ZnO samples have characteristic Raman vibration modes at 325 cm-1, and 434 cm-1 belonging to Wurtzite ZnO structure. Moreover, the prominent peak at 434 cm-1 which is the characteristic peak of E2(2) (high) mode of the Wurtzite ZnO and the E2(2) (high) has been red shifted by 4 cm-1, as compared to that found in the bulk ZnO. Additionally, the effect of carbon doping through Raman spectroscopy peak shifts of the E2(2) (high) mode, A1(LO) mode and multi-phonon has also been considered and discussed in detail. UV-Vis diffuse reflectance spectroscopy has revealed a red shift of the absorption edge with increase in C doping. Finally, the effect of nano-crystallite size and gradual prominence of C into ZnO lattice due to increase in C doping concentration in the PSP prepared nanoparticles was meticulously elaborated through Raman Spectroscopy analysis.
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- Authors: Ntozakhe, Luyolo
- Date: 2017
- Subjects: Zinc oxide -- Synthesis Nanoparticles
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/5862 , vital:29408
- Description: In this work, the pneumatic spray pyrolysis was used to synthesize un-doped and carbon doped zinc oxide (ZnO) nanoparticles. The zinc acetate, tetrabutylammonium bromide and ethanol were used as starting materials for the desired ZnO nanoparticles and the prepared samples were annealed at 400 oC in the furnace. The as synthesized un-doped and carbon doped ZnO NPs were evaluated using X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy dispersive x-ray spectroscopy (EDX), High-resolution transmission electron microscopy (HRTEM), Raman spectroscopy (RS) and Ultraviolet-visible spectroscopy (UV-Vis). XRD analysis of the synthesized NPs revealed peaks at 31.90°, 34.50°, 36.34°, 47.73°, 56.88°, 63.04°, 68.20°, and 77.33° belonging to the hexagonal Wurtzite ZnO crystal structure. The incorporation of C species into ZnO lattice was cross examined by monitoring the peak positions of the (100), (002) and (001) planes. These three main peaks of C-ZnO NPs show a peak shift to higher 2θ values which indicates substitutional carbon doping in ZnO NPs. SEM analysis has revealed that the as synthesized NPs have spherical shape and the morphology of the NPs change as the concentration of carbon increases. The EDX spectra of both un-doped and doped ZnO nanoparticles have revealed prominent peaks at 0.51 keV, 1.01 keV, 1.49 keV, 8.87 keV and 9.86 keV. Peaks at, X-ray energies of 0.51 keV and 1.01 keV respectively represent the emissions from the K-shell of oxygen and L-shell of zinc. The L-shell emission at 1.01 keV is considered as convolution of Zn 2p3/2 and Zn 2p1/2 photoelectron energies. The occurrence of these peaks in the EDX endorses the existence of Zn and O atoms in the PSP prepared samples. HRTEM analysis has revealed NPs size modal range from 6.65-14.21 nm for the PSP synthesized samples which is in mutual agreement with the XRD data calculated values. More over the selected area diffraction images displaying the fact that only the diffraction planes of (101), (002) and (100) are responsible for the diffraction pattern belonging to Wurtzite ZnO. RS analysis has revealed that the un-doped ZnO and doped ZnO samples have characteristic Raman vibration modes at 325 cm-1, and 434 cm-1 belonging to Wurtzite ZnO structure. Moreover, the prominent peak at 434 cm-1 which is the characteristic peak of E2(2) (high) mode of the Wurtzite ZnO and the E2(2) (high) has been red shifted by 4 cm-1, as compared to that found in the bulk ZnO. Additionally, the effect of carbon doping through Raman spectroscopy peak shifts of the E2(2) (high) mode, A1(LO) mode and multi-phonon has also been considered and discussed in detail. UV-Vis diffuse reflectance spectroscopy has revealed a red shift of the absorption edge with increase in C doping. Finally, the effect of nano-crystallite size and gradual prominence of C into ZnO lattice due to increase in C doping concentration in the PSP prepared nanoparticles was meticulously elaborated through Raman Spectroscopy analysis.
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