Synthesis, characterization and photophysical studies of RU(II)bipyridyl-dithiocarbamate complexes as sensitizers for dye sensitized solar cells
- Authors: Fudo, Zintle
- Date: 2018
- Subjects: Dye-sensitized solar cells Renewable energy sources
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/6168 , vital:29498
- Description: The depletion of fossil fuels and the increasing energy demand for energy has led to the search for better and improved technologies with special focus renewable energy, especially solar cells. The first generation solar cells based on silicon are expensive, hence dye sensitized solar cells come in as a better alternative as these solar cells are environmental friendly, they have moderately good conversion efficiency and they are relatively cheap to produce. Dithiocarbamate ligands have been widely used in many research fields, as these are versatile ligands. Coordination of dithiocarbamates with metals such as ruthenium has produced high conversion efficiency and have the ability to extend the MLCT absorptions, and this can further extend their wavelength. In this study five dithiocarbamate sodium salt ligands were prepared and were coded as FL1= Aniline, FL2= p- toluidine, FL3= p- anisidine, FL4=dibenzyl, FL5=diphenyl. These ligands were used to synthesize Ru(II) metal complexes which were formulated as [Ru(FLx)(dcbpy)(NCS)] and [Ru(FLx)2(dcbpy)] where FLx is the dithiocarbamate ligand and dcbpy is 2,2-bipyridine-4,4’-dicarboxylic acid and the complexes were coded as FCx. The synthesized compounds were characterized using techniques such as the melting point, molar conductivity, FT-IR and NMR spectroscopy. For spectroelectrochemical studies of the metal complexes, techniques such as UV-Vis and photoluminescence spectroscopy were carried out. Furthermore, redox properties of the complexes were analyzed using cyclic and square wave voltammetry. The FT-IR displayed all the expected peaks of interest both in the dithiocarbamate ligands and in the metal complexes. The electronic spectra confirmed the successful coordination of ligand to the metal centre, the electronic spectra of the complexes also confirmed the six coordinate octahedral geometry of the complexes. The complexes exhibited some photoluminescence properties that are suitable for dye sensitization. The cyclic voltammogram of the complexes displayed more reduction potentials that could be attributed to the π-conjugation in the ligands incorporated during synthesis. The square wave voltammogram of the complexes is in agreement with the results obtained in cyclic voltammetry.
- Full Text:
- Authors: Fudo, Zintle
- Date: 2018
- Subjects: Dye-sensitized solar cells Renewable energy sources
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/6168 , vital:29498
- Description: The depletion of fossil fuels and the increasing energy demand for energy has led to the search for better and improved technologies with special focus renewable energy, especially solar cells. The first generation solar cells based on silicon are expensive, hence dye sensitized solar cells come in as a better alternative as these solar cells are environmental friendly, they have moderately good conversion efficiency and they are relatively cheap to produce. Dithiocarbamate ligands have been widely used in many research fields, as these are versatile ligands. Coordination of dithiocarbamates with metals such as ruthenium has produced high conversion efficiency and have the ability to extend the MLCT absorptions, and this can further extend their wavelength. In this study five dithiocarbamate sodium salt ligands were prepared and were coded as FL1= Aniline, FL2= p- toluidine, FL3= p- anisidine, FL4=dibenzyl, FL5=diphenyl. These ligands were used to synthesize Ru(II) metal complexes which were formulated as [Ru(FLx)(dcbpy)(NCS)] and [Ru(FLx)2(dcbpy)] where FLx is the dithiocarbamate ligand and dcbpy is 2,2-bipyridine-4,4’-dicarboxylic acid and the complexes were coded as FCx. The synthesized compounds were characterized using techniques such as the melting point, molar conductivity, FT-IR and NMR spectroscopy. For spectroelectrochemical studies of the metal complexes, techniques such as UV-Vis and photoluminescence spectroscopy were carried out. Furthermore, redox properties of the complexes were analyzed using cyclic and square wave voltammetry. The FT-IR displayed all the expected peaks of interest both in the dithiocarbamate ligands and in the metal complexes. The electronic spectra confirmed the successful coordination of ligand to the metal centre, the electronic spectra of the complexes also confirmed the six coordinate octahedral geometry of the complexes. The complexes exhibited some photoluminescence properties that are suitable for dye sensitization. The cyclic voltammogram of the complexes displayed more reduction potentials that could be attributed to the π-conjugation in the ligands incorporated during synthesis. The square wave voltammogram of the complexes is in agreement with the results obtained in cyclic voltammetry.
- Full Text:
An investigation on the motivational feattures influence on technical efficiency and profitability of smallholder irrigated crop farmers in Kwa-Nobuhle, Eastern Cape province of South Africa
- Authors: Funde, Sibongile
- Date: 2017
- Subjects: Crops -- South Africa -- Eastern Cape -- Marketing Irrigation farming -- South Africa -- Eastern Cape Agriculture -- Economic aspects -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/11917 , vital:39118
- Description: Substantial impact and the importance of agriculture in the economies of the developing countries is increasingly acknowledged. Agriculture generally has shown to remain crucial to economic development. It has been noted that agricultural growth plays a pivotal role in poverty reduction and employment creation. Due to the potential of the smallholder sector to alleviate poverty and minimize unemployment rate leading to the country’s economic growth, enormous development programs have in the past and continues to be implemented by South African government. Programs such as land-based development strategies including agriculture, extension services, improved technologies including irrigation establishment, revitalization and rehabilitation, water rights legislation and financial support. However, the current state of smallholder low-agricultural productivity growth trends raises concerns on what other fundamental development strategies to implement in order to enhance agricultural productivity growth. Hence, this study seeks to address the impact of social farming on agricultural productivity by investigating smallholder farmer’s motivational features. Motivational features regarded are as important determinants of success, modify behaviour, serve to mobilize and direct energy into actions. Given the importance of motivational features and their formation in social interaction, the objective of the study was to investigate motivational features of smallholder farmers with regard to expanding irrigation land, determine technical efficiency of smallholder farmers as well as their profitability generation capability. A multistage sampling method was used that involved using purposive sampling, simple random sampling was adopted where three smallholder agriculture projects using irrigation methods to farm were selected and by use of snowball sampling the study ended up collecting data from a total of 124 respondents. The sample was chosen on the basis that smallholder farmers hold attributes that were crucial for execution of this research. The study proceeded by conducting face-to face interviews of smallholder farmers, focus groups and key informant using interview schedules and a questionnaire consisting both open and close-ended questions. Data were analysed using different methods. Firstly, data were analysed descriptively to get a deeper understanding of smallholder farmer’s socio-economic characteristics as well as their motivational features. Secondly, data were analysed statistically to determine Technical Efficiency (TE) of smallholder farmers using both Data Envelopment Analysis (DEA) and Stochastic Frontier Analysis (SFA). Lastly, Gross Margin Analysis was used to measure farmer’s profitability. Results show that smallholder farmers have a range of motivational features that incorporates both productive and non-productive goals. The study made use of twenty-five goals obtained from literature studies and categorised them into six motivational feature types namely; outcome based, process focused/extrinsic, performance, achievement, intrinsic/self-efficacy, and household livelihood strategies. Smallholder female and male outcome based motivations were found to be statistically significant at 5percent, while process focused/extrinsic, performance, achievement, intrinsic/self-efficacy and household livelihood strategies motivations between them were found not to be statistically significant, which means that smallholder female and male motivations are not different and that both farmers consider such motivations at the same level. Technical Efficiency (TE) was measured using DEA method and was found to be 0.70, which is different from the TE obtained using SFA that was 0.47. Three dominant crops were produced, namely potatoes, cabbage and spinach. Cabbage crop was the most produced, had the highest gross margin results with a commercialization ratio of 0.33percent as compared to potatoes and spinach. Which indicates that cabbage is a high value crop to smallholder farmers of Kwa-Nobuhle area. In view of the research findings, it was concluded that motivational features of smallholder farmers were positively related to technical efficiency which implies that the more motivated farmers become, the higher their technical efficiency, hence their potential to expand land under irrigation. Cabbage production was high and more profitable than potatoes and spinach production. Recommendations include that government, NGO’s, private sector and institution need to promote the use of improved technologies, agricultural training and take smallholder farmer’s motivational features into account in development programmes. These actions are necessary to increase irrigated farming, overcome low-performance levels and enhance profitability of smallholder farmers, and ultimately achieve poverty alleviation and improve employment opportunities in the rural areas.
- Full Text:
- Authors: Funde, Sibongile
- Date: 2017
- Subjects: Crops -- South Africa -- Eastern Cape -- Marketing Irrigation farming -- South Africa -- Eastern Cape Agriculture -- Economic aspects -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/11917 , vital:39118
- Description: Substantial impact and the importance of agriculture in the economies of the developing countries is increasingly acknowledged. Agriculture generally has shown to remain crucial to economic development. It has been noted that agricultural growth plays a pivotal role in poverty reduction and employment creation. Due to the potential of the smallholder sector to alleviate poverty and minimize unemployment rate leading to the country’s economic growth, enormous development programs have in the past and continues to be implemented by South African government. Programs such as land-based development strategies including agriculture, extension services, improved technologies including irrigation establishment, revitalization and rehabilitation, water rights legislation and financial support. However, the current state of smallholder low-agricultural productivity growth trends raises concerns on what other fundamental development strategies to implement in order to enhance agricultural productivity growth. Hence, this study seeks to address the impact of social farming on agricultural productivity by investigating smallholder farmer’s motivational features. Motivational features regarded are as important determinants of success, modify behaviour, serve to mobilize and direct energy into actions. Given the importance of motivational features and their formation in social interaction, the objective of the study was to investigate motivational features of smallholder farmers with regard to expanding irrigation land, determine technical efficiency of smallholder farmers as well as their profitability generation capability. A multistage sampling method was used that involved using purposive sampling, simple random sampling was adopted where three smallholder agriculture projects using irrigation methods to farm were selected and by use of snowball sampling the study ended up collecting data from a total of 124 respondents. The sample was chosen on the basis that smallholder farmers hold attributes that were crucial for execution of this research. The study proceeded by conducting face-to face interviews of smallholder farmers, focus groups and key informant using interview schedules and a questionnaire consisting both open and close-ended questions. Data were analysed using different methods. Firstly, data were analysed descriptively to get a deeper understanding of smallholder farmer’s socio-economic characteristics as well as their motivational features. Secondly, data were analysed statistically to determine Technical Efficiency (TE) of smallholder farmers using both Data Envelopment Analysis (DEA) and Stochastic Frontier Analysis (SFA). Lastly, Gross Margin Analysis was used to measure farmer’s profitability. Results show that smallholder farmers have a range of motivational features that incorporates both productive and non-productive goals. The study made use of twenty-five goals obtained from literature studies and categorised them into six motivational feature types namely; outcome based, process focused/extrinsic, performance, achievement, intrinsic/self-efficacy, and household livelihood strategies. Smallholder female and male outcome based motivations were found to be statistically significant at 5percent, while process focused/extrinsic, performance, achievement, intrinsic/self-efficacy and household livelihood strategies motivations between them were found not to be statistically significant, which means that smallholder female and male motivations are not different and that both farmers consider such motivations at the same level. Technical Efficiency (TE) was measured using DEA method and was found to be 0.70, which is different from the TE obtained using SFA that was 0.47. Three dominant crops were produced, namely potatoes, cabbage and spinach. Cabbage crop was the most produced, had the highest gross margin results with a commercialization ratio of 0.33percent as compared to potatoes and spinach. Which indicates that cabbage is a high value crop to smallholder farmers of Kwa-Nobuhle area. In view of the research findings, it was concluded that motivational features of smallholder farmers were positively related to technical efficiency which implies that the more motivated farmers become, the higher their technical efficiency, hence their potential to expand land under irrigation. Cabbage production was high and more profitable than potatoes and spinach production. Recommendations include that government, NGO’s, private sector and institution need to promote the use of improved technologies, agricultural training and take smallholder farmer’s motivational features into account in development programmes. These actions are necessary to increase irrigated farming, overcome low-performance levels and enhance profitability of smallholder farmers, and ultimately achieve poverty alleviation and improve employment opportunities in the rural areas.
- Full Text:
Distribution of culturable vibrio species in freshwater resources of Cacadu, or Tambo and Chris Hani district municipalities
- Authors: Gaqavu, Sisipho
- Date: 2017
- Subjects: Vibrio--South Africa--Eastern Cape Vibrio infections--South Africa--Eastern Cape Foodborne diseases--South Africa--Eastern Cape
- Language: English
- Type: Thesis , Masters , Microbiology
- Identifier: http://hdl.handle.net/10353/11571 , vital:39085
- Description: Freshwater resources are essential to the survival of all living organisms and are used for numerous purposes such as domestic, industrial, agricultural and recreational activities. Nevertheless they are vulnerable to contamination including by pathogenic organisms. Among the pathogens distributed in water resources, diarrhoea causing pathogens such as Vibrio species are the most frequently encountered, hence, the aim of this study was to evaluate the incidence of pathogenic Vibrio species in freshwater resources in Cacadu, OR Tambo and Chris Hani District Municipalities. Water samples were collected from four rivers located in Cacadu, OR Tambo and Chris Hani District Municipalities in the Eastern Cape Province, South Africa. A total of 6 physicochemical parameterswere measured and includes: temperature, total dissolved solids (TDS), dissolved oxygen, turbidity, pH and electrical conductivity. Samples were collected between March and May 2016and concentrated using the standard membrane filtration technique and plated on TCBS agar. Yellow and green colonies on TCBS agar were enumerated as presumptive Vibrio species and expressed as CFU/100ml for each river. The identification of the presumptive Vibrio species and their antibiogram characteristics were done using both culture based and molecular techniques. The physicochemical qualities ranged as follows: pH (7.0-7.03), temperature (16 - 23 ºC), turbidity (15.6 – 43 NTU), electrical conductivity (61.1 – 835μS/cm), dissolved oxygen (7.34 – 8.73 mg/L), total dissolved solids (39.3 – 533.33 mg/L). Statistical analysis showed that pH, temperature, turbidity, dissolved oxygen were significantly different (P < 0.05), whereas the total dissolved solids were not significantly different (P ˃ 0.05) with respect to sampling sites. Vibrio densities ranged between 3.08 ×101-6.96 ×101 with Bloukrans River characterized by high counts compared to other rivers. Two hundred and three (203) positive Vibrio genus isolates were screened for speciation. Of these, the prevalent species found was V. cholerae (29percent) followed by V. vulnificus (4percent), V. fluvialis (4percent) and the least was V. parahaemolyticus (3percent). The remaining unidentified 60percent were alleged to belong to other Vibrio species not covered within the scope of this study. The antibiotic susceptibility profiles of confirmed Vibrio genus isolates recovered from the four rivers revealed that 83percent of Vibrio isolates in this study exhibited resistance againstthree or more antimicrobial agents. The presence of the following Vibrio pathogens V. fluvialis, V. cholerae, V. vulnificus and V. parahaemolyticus in water resources suggests that these water resources are significant reservoirs of Vibrio pathogens. Thus, there is a need for regular contamination monitoring programme of the selected water resources and other areas that might be of interest. In general, the results obtained from this study suggest that the river waters are not suitable for drinking, domestic or recreational use.
- Full Text:
- Authors: Gaqavu, Sisipho
- Date: 2017
- Subjects: Vibrio--South Africa--Eastern Cape Vibrio infections--South Africa--Eastern Cape Foodborne diseases--South Africa--Eastern Cape
- Language: English
- Type: Thesis , Masters , Microbiology
- Identifier: http://hdl.handle.net/10353/11571 , vital:39085
- Description: Freshwater resources are essential to the survival of all living organisms and are used for numerous purposes such as domestic, industrial, agricultural and recreational activities. Nevertheless they are vulnerable to contamination including by pathogenic organisms. Among the pathogens distributed in water resources, diarrhoea causing pathogens such as Vibrio species are the most frequently encountered, hence, the aim of this study was to evaluate the incidence of pathogenic Vibrio species in freshwater resources in Cacadu, OR Tambo and Chris Hani District Municipalities. Water samples were collected from four rivers located in Cacadu, OR Tambo and Chris Hani District Municipalities in the Eastern Cape Province, South Africa. A total of 6 physicochemical parameterswere measured and includes: temperature, total dissolved solids (TDS), dissolved oxygen, turbidity, pH and electrical conductivity. Samples were collected between March and May 2016and concentrated using the standard membrane filtration technique and plated on TCBS agar. Yellow and green colonies on TCBS agar were enumerated as presumptive Vibrio species and expressed as CFU/100ml for each river. The identification of the presumptive Vibrio species and their antibiogram characteristics were done using both culture based and molecular techniques. The physicochemical qualities ranged as follows: pH (7.0-7.03), temperature (16 - 23 ºC), turbidity (15.6 – 43 NTU), electrical conductivity (61.1 – 835μS/cm), dissolved oxygen (7.34 – 8.73 mg/L), total dissolved solids (39.3 – 533.33 mg/L). Statistical analysis showed that pH, temperature, turbidity, dissolved oxygen were significantly different (P < 0.05), whereas the total dissolved solids were not significantly different (P ˃ 0.05) with respect to sampling sites. Vibrio densities ranged between 3.08 ×101-6.96 ×101 with Bloukrans River characterized by high counts compared to other rivers. Two hundred and three (203) positive Vibrio genus isolates were screened for speciation. Of these, the prevalent species found was V. cholerae (29percent) followed by V. vulnificus (4percent), V. fluvialis (4percent) and the least was V. parahaemolyticus (3percent). The remaining unidentified 60percent were alleged to belong to other Vibrio species not covered within the scope of this study. The antibiotic susceptibility profiles of confirmed Vibrio genus isolates recovered from the four rivers revealed that 83percent of Vibrio isolates in this study exhibited resistance againstthree or more antimicrobial agents. The presence of the following Vibrio pathogens V. fluvialis, V. cholerae, V. vulnificus and V. parahaemolyticus in water resources suggests that these water resources are significant reservoirs of Vibrio pathogens. Thus, there is a need for regular contamination monitoring programme of the selected water resources and other areas that might be of interest. In general, the results obtained from this study suggest that the river waters are not suitable for drinking, domestic or recreational use.
- Full Text:
Isolation and characterization of extracts of Rosmarinus officinalis l. And comparative evaluation of its antimicrobial activity and selected types of antibiotics against some bacteria species
- Authors: Gbede,Remi
- Date: 2019
- Subjects: Rosmarinus Essences and essential oils Lamiaceae Medicinal plants
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/19142 , vital:39875
- Description: Rosmarinus officinalis L. is known extensively for its multifunctional purposes. The essential oil has been widely used in cosmeceuticals and several ethnopharmacological values. In vitro studies have demonstrated the antibacterial activity of essential oils (EOs) of Rosmarinus officinalis L. against Staphylococcus aureus ATCC 25923, Vibrio cholerae DSM 19283, Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 27853 and Bacillus cereus. These different bacteria were screened against antibiotics such as Tetracycline, Ampicillin Sodium salt, Erythromycin and Amoxicillin, and some standards namely rosmarinic acid, carnosic acid and carnosol, and also against the methanol, acetone, chloroform and dichloromethane extracts of rosemary. The essential oils of Rosmarinus officinalis L. showed significant inhibitory properties compared to antibiotics with various degrees of growth inhibition. The standards exhibited some activities against the organisms. The GC/MS analysis of the essential oil revealed 34 compounds present with most components acting in synergy to bring about antibacterial activities. The antiplasmodial and cytotoxic activities of two leaf extracts of Rosmarinus officinalis (with hexane and dichloromethane as solvents) using standard procedure were studied. The findings justify the claims on the efficacy of plants for therapeutic uses for antifungal, antibacterial and anti-inflammatory properties. Antiplasmodial activity of Rosmarinus officinalis recorded IC50 values of 9.99 µg/ml and 9.76 µg/ml in hexane and dichloromethane respectively.
- Full Text:
- Authors: Gbede,Remi
- Date: 2019
- Subjects: Rosmarinus Essences and essential oils Lamiaceae Medicinal plants
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/19142 , vital:39875
- Description: Rosmarinus officinalis L. is known extensively for its multifunctional purposes. The essential oil has been widely used in cosmeceuticals and several ethnopharmacological values. In vitro studies have demonstrated the antibacterial activity of essential oils (EOs) of Rosmarinus officinalis L. against Staphylococcus aureus ATCC 25923, Vibrio cholerae DSM 19283, Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 27853 and Bacillus cereus. These different bacteria were screened against antibiotics such as Tetracycline, Ampicillin Sodium salt, Erythromycin and Amoxicillin, and some standards namely rosmarinic acid, carnosic acid and carnosol, and also against the methanol, acetone, chloroform and dichloromethane extracts of rosemary. The essential oils of Rosmarinus officinalis L. showed significant inhibitory properties compared to antibiotics with various degrees of growth inhibition. The standards exhibited some activities against the organisms. The GC/MS analysis of the essential oil revealed 34 compounds present with most components acting in synergy to bring about antibacterial activities. The antiplasmodial and cytotoxic activities of two leaf extracts of Rosmarinus officinalis (with hexane and dichloromethane as solvents) using standard procedure were studied. The findings justify the claims on the efficacy of plants for therapeutic uses for antifungal, antibacterial and anti-inflammatory properties. Antiplasmodial activity of Rosmarinus officinalis recorded IC50 values of 9.99 µg/ml and 9.76 µg/ml in hexane and dichloromethane respectively.
- Full Text:
Incidence of cholera-causing and non cholera-causing pathogenic vibrio species in the river-k and two of its feeder wastewater treatment plants in the Raymond Mhlaba municipality, Eastern Cape province of South Africa
- Authors: Gcilitshana, Onele
- Date: 2019
- Subjects: Water -- Purification -- South Africa -- Eastern Cape Effluent quality -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15145 , vital:40190
- Description: Despite technological advances in water treatment and improved sanitation in many developing countries, acute microbial diseases still thrive and continue to distress millions of people. This is due to the high number of rural dwellers that still source water for drinking and other domestic uses from contaminated rivers. In South Africa, there have been reports on waterborne disease outbreaks, and specifically in the area understudy, two records of diarrhoeal outbreaks associated with consumption of river water were reported within the last decade. All those outbreaks and previous reports on isolation of other pathogenic bacteria within the area necessitated the conduction of this study in order to identify the potential causes of the cholera-associate diarrheal outbreaks previously reported in the area and nationally. This study was designed to assess the incidence of cholera-causing and non-cholera causing pathogens in final effluents and surface waters of the Raymond Mhlaba Local Municipality, Eastern Cape Province, South Africa. RiverK which serves as a major resource for domestic activities, agricultural practices as well as an abstraction point for a potable water treatment plant was used for this study. River-K freshwater and final effluents of its two feeder wastewater treatment plants were sampled monthly, over a twelve-month period (December 2016–November 2017). For purposes of confidentiality, the names of the wastewater treatment plants and river involved are coded in this report. A total of 108 water samples were assessed for the physicochemical parameters that influence the presence of Vibrio pathogens. For bacteriology, the membrane filtration method followed by polymerase chain reaction (PCR) was adopted to assess the incidence of cholera-causing and non-choleracausing Vibrio pathogens, as well as their virulence-associated genes from the two wastewater treatment plants and their receiving waterbody (River-K). Antibiotic susceptibility profiles of identified Vibrio species were determined using the disc diffusion method against a panel of xvi sixteen antibiotics commonly used as antimicrobial drugs of Vibrio infections. Multiple antibiotics resistance index (MARI) and phenotypes (MARP) were measured, and the existence of antibiotic resistance genes was evaluated by PCR using specific primer sets. Most of the physicochemical parameters measured (pH, TDS, temperature, salinity and DO) complied with the recommended standards for drinking water, while some fell short of the recommended limits (EC, turbidity, TSS, free chlorine). From the presumptive Vibrio isolates, 64.3% (476/740) were confirmed by PCR, with their Vibrio densities across all sampling points ranging between 0 and 2.7 × 104 CFU/100 mL, with high counts recorded in summer, hence their positive significant correlation (P< 0.01) with temperature. From the confirmed Vibrio isolates, only V. cholerae (53/476), V. mimicus (21/476) and V. parahaemolyticus (5/476) were detected. For virulence-associated genes, virulence genes homologous to V. cholerae virulence determinants, namely ompU (35%), TCP (14%), ACE (11%), ctx (7%) and HylA (4.5%) were widespread (independently) amongst the V. cholerae and V. mimicus species, while V. parahemolyticus isolates (100%) produced only the ToxR gene. Antibiogram profiling found resistance against some antibiotics such as Nalidixic acid (65%), Polymyxin B (43.8%) etc. The MAR indices ranged between 0 and 0.67 with 41.3% of the isolates recording MAR index values above 0.2. The results presented high degrees of MARPs ranging from four to eleven antimicrobials. For resistance gene detection, the SXT element was detected in 66% of the isolates, while cat1 (93%) was the most predominant, followed by aac (68%), ant (61%), with bla-V (7.1%) as the least detected gene. Findings from this study suggest that the wastewater effluents from the two wastewater treatment plants are potential sources of pathogenic Vibrio species and River-K contains a high quantity of pathogenic Vibrio species with fluctuating seasonal variations that reaffirm temperature as a strong reason for their abundance. The antibiotic-resistant Vibrio species isolated here carry a pool of virulence-associated genes and xvii antibiotic resistance genes, presenting a health threat to the communities that use it directly for domestic and irrigation purposes. In conclusion, some surface waters in the Eastern Cape Province, South Africa are widely contaminated with cholera-causing and non-cholera causing Vibrio pathogens; furthermore, some wastewater treatment plants are ineffective in adequately removing microbial contaminants and have become sources of pathogenic bacteria to their receiving waterbodie
- Full Text:
- Authors: Gcilitshana, Onele
- Date: 2019
- Subjects: Water -- Purification -- South Africa -- Eastern Cape Effluent quality -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15145 , vital:40190
- Description: Despite technological advances in water treatment and improved sanitation in many developing countries, acute microbial diseases still thrive and continue to distress millions of people. This is due to the high number of rural dwellers that still source water for drinking and other domestic uses from contaminated rivers. In South Africa, there have been reports on waterborne disease outbreaks, and specifically in the area understudy, two records of diarrhoeal outbreaks associated with consumption of river water were reported within the last decade. All those outbreaks and previous reports on isolation of other pathogenic bacteria within the area necessitated the conduction of this study in order to identify the potential causes of the cholera-associate diarrheal outbreaks previously reported in the area and nationally. This study was designed to assess the incidence of cholera-causing and non-cholera causing pathogens in final effluents and surface waters of the Raymond Mhlaba Local Municipality, Eastern Cape Province, South Africa. RiverK which serves as a major resource for domestic activities, agricultural practices as well as an abstraction point for a potable water treatment plant was used for this study. River-K freshwater and final effluents of its two feeder wastewater treatment plants were sampled monthly, over a twelve-month period (December 2016–November 2017). For purposes of confidentiality, the names of the wastewater treatment plants and river involved are coded in this report. A total of 108 water samples were assessed for the physicochemical parameters that influence the presence of Vibrio pathogens. For bacteriology, the membrane filtration method followed by polymerase chain reaction (PCR) was adopted to assess the incidence of cholera-causing and non-choleracausing Vibrio pathogens, as well as their virulence-associated genes from the two wastewater treatment plants and their receiving waterbody (River-K). Antibiotic susceptibility profiles of identified Vibrio species were determined using the disc diffusion method against a panel of xvi sixteen antibiotics commonly used as antimicrobial drugs of Vibrio infections. Multiple antibiotics resistance index (MARI) and phenotypes (MARP) were measured, and the existence of antibiotic resistance genes was evaluated by PCR using specific primer sets. Most of the physicochemical parameters measured (pH, TDS, temperature, salinity and DO) complied with the recommended standards for drinking water, while some fell short of the recommended limits (EC, turbidity, TSS, free chlorine). From the presumptive Vibrio isolates, 64.3% (476/740) were confirmed by PCR, with their Vibrio densities across all sampling points ranging between 0 and 2.7 × 104 CFU/100 mL, with high counts recorded in summer, hence their positive significant correlation (P< 0.01) with temperature. From the confirmed Vibrio isolates, only V. cholerae (53/476), V. mimicus (21/476) and V. parahaemolyticus (5/476) were detected. For virulence-associated genes, virulence genes homologous to V. cholerae virulence determinants, namely ompU (35%), TCP (14%), ACE (11%), ctx (7%) and HylA (4.5%) were widespread (independently) amongst the V. cholerae and V. mimicus species, while V. parahemolyticus isolates (100%) produced only the ToxR gene. Antibiogram profiling found resistance against some antibiotics such as Nalidixic acid (65%), Polymyxin B (43.8%) etc. The MAR indices ranged between 0 and 0.67 with 41.3% of the isolates recording MAR index values above 0.2. The results presented high degrees of MARPs ranging from four to eleven antimicrobials. For resistance gene detection, the SXT element was detected in 66% of the isolates, while cat1 (93%) was the most predominant, followed by aac (68%), ant (61%), with bla-V (7.1%) as the least detected gene. Findings from this study suggest that the wastewater effluents from the two wastewater treatment plants are potential sources of pathogenic Vibrio species and River-K contains a high quantity of pathogenic Vibrio species with fluctuating seasonal variations that reaffirm temperature as a strong reason for their abundance. The antibiotic-resistant Vibrio species isolated here carry a pool of virulence-associated genes and xvii antibiotic resistance genes, presenting a health threat to the communities that use it directly for domestic and irrigation purposes. In conclusion, some surface waters in the Eastern Cape Province, South Africa are widely contaminated with cholera-causing and non-cholera causing Vibrio pathogens; furthermore, some wastewater treatment plants are ineffective in adequately removing microbial contaminants and have become sources of pathogenic bacteria to their receiving waterbodie
- Full Text:
Knowledge and attitudes of professional nurses towards HIV and AIDS patients at the Libode District Health Services in the Eastern Cape Province
- Authors: Gedu, Grace Nontuthuzelo
- Date: 2011-12
- Subjects: Rural health services , AIDS (Disease)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24610 , vital:63213
- Description: This study was conducted at the Libode District Health Services amongst professional nurses who render services to HIV and AIDS patients. Generally, caring for HIV positive patients, nurses need to be knowledgeable about the transmission of the HIV virus, in order to render quality care to the patients. They also need to be sensitive and to demonstrate positive attitudes towards the patients. It was unknown whether the professional nurses at the Libode District Health Services are knowledgeable or not regarding HIV and AIDS. Their attitudes towards the HIV positive patients, were also unknown. Not knowing the knowledge and attitude of professional nurses regarding HIV and AIDS has the potential to compromise the quality of nursing care rendered to the patients. The purpose of the study was to explore and describe the level of knowledge of professional nurses regarding HIV and AIDS well as their attitudes towards the HIV-positive patients so as to make recommendations for quality patient care based on the results. A quantitative explorative descriptive research design was used to examine the level of knowledge about HIV and AIDS as well as the attitudes of professional nurses to HIV and AIDS patients. The target populations were the 218 professional nurses working at the Libode District Health services who had nursed HIV positive patients. A simple random sampling method was used to select a sample of 120 participants. A structured self-administered questionnaire was used to obtain data. The questionnaire consisted of a section on the demographic profile of the participants, and two other sections for responses on knowledge and attitudes. Data were analyzed using Statistical Package for the Social Sciences (SPSS) version 17.0 software for consistency of the twenty (20) items in the questionnaire. Findings showed that nurses of Libode District Health Services had an approximately fair amount of knowledge. The majority (79percent) of participants scored above the cut-off point of 24. Twenty one percent (21percent) scored below 24. On attitude, the majority (76percent) had scored below the cut-off point of 36. Recommendations were that professional nurses of Libode District Health Services, need to be exposed to ongoing training on HIV and AIDS to increase their knowledge about HIV and AIDS and to ensure that they demonstrate positive attitudes towards HIV and AIDS patients. , Thesis (MSc) -- Faculty of Science and Agriculture, 2011
- Full Text:
- Authors: Gedu, Grace Nontuthuzelo
- Date: 2011-12
- Subjects: Rural health services , AIDS (Disease)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24610 , vital:63213
- Description: This study was conducted at the Libode District Health Services amongst professional nurses who render services to HIV and AIDS patients. Generally, caring for HIV positive patients, nurses need to be knowledgeable about the transmission of the HIV virus, in order to render quality care to the patients. They also need to be sensitive and to demonstrate positive attitudes towards the patients. It was unknown whether the professional nurses at the Libode District Health Services are knowledgeable or not regarding HIV and AIDS. Their attitudes towards the HIV positive patients, were also unknown. Not knowing the knowledge and attitude of professional nurses regarding HIV and AIDS has the potential to compromise the quality of nursing care rendered to the patients. The purpose of the study was to explore and describe the level of knowledge of professional nurses regarding HIV and AIDS well as their attitudes towards the HIV-positive patients so as to make recommendations for quality patient care based on the results. A quantitative explorative descriptive research design was used to examine the level of knowledge about HIV and AIDS as well as the attitudes of professional nurses to HIV and AIDS patients. The target populations were the 218 professional nurses working at the Libode District Health services who had nursed HIV positive patients. A simple random sampling method was used to select a sample of 120 participants. A structured self-administered questionnaire was used to obtain data. The questionnaire consisted of a section on the demographic profile of the participants, and two other sections for responses on knowledge and attitudes. Data were analyzed using Statistical Package for the Social Sciences (SPSS) version 17.0 software for consistency of the twenty (20) items in the questionnaire. Findings showed that nurses of Libode District Health Services had an approximately fair amount of knowledge. The majority (79percent) of participants scored above the cut-off point of 24. Twenty one percent (21percent) scored below 24. On attitude, the majority (76percent) had scored below the cut-off point of 36. Recommendations were that professional nurses of Libode District Health Services, need to be exposed to ongoing training on HIV and AIDS to increase their knowledge about HIV and AIDS and to ensure that they demonstrate positive attitudes towards HIV and AIDS patients. , Thesis (MSc) -- Faculty of Science and Agriculture, 2011
- Full Text:
Computational fluid dynamics design and performance testing of a cyclone heat exchanger used in a gasification plant
- Authors: George, Tomy
- Date: 2019
- Subjects: Computational fluid dynamics Renewable energy sources Biomass gasification
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/19087 , vital:39877
- Description: Renewable energy resources are considered to be the most promising source of energy in the coming centuries owing to its potential to get replenished by the nature itself. However, there are a number of challenges that are to be addressed prior to considering a particular resource as a reliable and effective one according to the energy demand fluctuations. Energy extracted from the biomass available in the nature has a lot of potential especially in the case of producing energy from syngas produced by the controlled burning of wood. This research deals with the minimisation of energy wastage in a gasification plant where syngas is produced from wood and transferred to an internal combustion engine to further generate electrical energy. The syngas produced from the wood is to be fed through a cyclone for purification before it can be fed into the IC engine, where the dust, carbon and other impurities are separated from the syngas by making use of the centrifugal force developed inside the cyclone. This syngas is further cooled and fed into the IC engine in its purest form as specified by the requirements of the engine. It is envisaged that if it is possible to recover the heat energy otherwise wasted in the cyclone and through the cooling circuit, it can be used for preheating the wood or for other minor heating purposes, and thereby the heat wastage can be minimised. Therefore, in this research, a series of numerical investigation conducted which involved the modelling of heat exchanger around a cyclone in order to extract heat from the surface of the cyclone. Two basic design of the Heat exchanger were considered in the study, a rectangular and a conical design. With a water flow rate of 2 l/min in conical design, the heat absorbed by the water was found to be 5.555 kJ/s and in rectangular design, the heat absorbed by the water was 4.872 kJ/s. An experimental analysis conducted to validate the simulation by a rectangular Heat exchanger shows the amount of heat absorbed by the water is 4.87 kJ/s. In a study with variable water flow rate through the jacket, it is observed that heat absorbed by the water in conical heat exchanger is more than heat absorbed by the water in rectangular jacket within the flow rate of 4 l/min. and the heat absorbed by the water in rectangular heat exchanger is higher than conical heat exchanger with water flow rate above 4 l/min.
- Full Text:
- Authors: George, Tomy
- Date: 2019
- Subjects: Computational fluid dynamics Renewable energy sources Biomass gasification
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/19087 , vital:39877
- Description: Renewable energy resources are considered to be the most promising source of energy in the coming centuries owing to its potential to get replenished by the nature itself. However, there are a number of challenges that are to be addressed prior to considering a particular resource as a reliable and effective one according to the energy demand fluctuations. Energy extracted from the biomass available in the nature has a lot of potential especially in the case of producing energy from syngas produced by the controlled burning of wood. This research deals with the minimisation of energy wastage in a gasification plant where syngas is produced from wood and transferred to an internal combustion engine to further generate electrical energy. The syngas produced from the wood is to be fed through a cyclone for purification before it can be fed into the IC engine, where the dust, carbon and other impurities are separated from the syngas by making use of the centrifugal force developed inside the cyclone. This syngas is further cooled and fed into the IC engine in its purest form as specified by the requirements of the engine. It is envisaged that if it is possible to recover the heat energy otherwise wasted in the cyclone and through the cooling circuit, it can be used for preheating the wood or for other minor heating purposes, and thereby the heat wastage can be minimised. Therefore, in this research, a series of numerical investigation conducted which involved the modelling of heat exchanger around a cyclone in order to extract heat from the surface of the cyclone. Two basic design of the Heat exchanger were considered in the study, a rectangular and a conical design. With a water flow rate of 2 l/min in conical design, the heat absorbed by the water was found to be 5.555 kJ/s and in rectangular design, the heat absorbed by the water was 4.872 kJ/s. An experimental analysis conducted to validate the simulation by a rectangular Heat exchanger shows the amount of heat absorbed by the water is 4.87 kJ/s. In a study with variable water flow rate through the jacket, it is observed that heat absorbed by the water in conical heat exchanger is more than heat absorbed by the water in rectangular jacket within the flow rate of 4 l/min. and the heat absorbed by the water in rectangular heat exchanger is higher than conical heat exchanger with water flow rate above 4 l/min.
- Full Text:
Entrepreneurial development paths and livelihood strategies in smallholder irrigation schemes in the Eastern Cape province, South Africa
- Gidi, Lungile Sivuyile https://orcid.org/0000-0002-2896-2709
- Authors: Gidi, Lungile Sivuyile https://orcid.org/0000-0002-2896-2709
- Date: 2016-07
- Subjects: Farms, Small , Irrigation farming -- Economic aspects
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/24906 , vital:63670
- Description: South Africa has implemented several successful rural poverty relief initiatives; however, poverty continues to strain rural development efforts. The aim of the study was to analyse the entrepreneurial development paths and livelihood strategies in smallholder irrigation schemes in the Eastern Cape Province of South Africa. The study has outlined five hypothesizes for the basis of concrete scientific research. Initially the study hypothesizes that a smallholder’s socio-cultural contexts such as village level institutions especially village governance as well as household circumstances including age, education and gender compositions of the household membership as well as household income can determine a smallholder’s transformation ability. The second hypothesis was that alternative economic activities especially farming activities such as livestock and crop production as well as off-farm economic opportunities which were open to a household could influence a smallholder’s willingness to change from homestead gardening to food crop production under government irrigation programme. The third hypothesis was on the smallholder’s assessment of available market for the products of his or her food crop irrigation farming which could be an important consideration in his or her willingness to change. The fourth assumption was that entrepreneurial skills are lacking, in particular the ability to search for opportunities and willingness to do something different than the masses and take risks in that process. Finally, the study hypothesized that the government irrigation scheme governance could determine the attractiveness of the scheme and thereby influencing the willingness of a smallholder to participate. Specifically, the legal and regulatory environments are very restrictive and they are not conducive to effective value and job creation in the villages and for the principal crop and livestock enterprises. The study used cross-sectional data collected from both scheme farmers and non-scheme farmers. There were 107 smallholder farmers administered. Cobb-Douglass production and Multiple Regression Models were used. The results indicated 62 percent were male household head and 38 percent were female household head. The majority of the farmers were above middle age for both men and women households head. Specifically, about 80percent were above 51 years of age. Wage employment on the other hand contributed 8percent for both scheme and non-scheme farmers. The majority of the family members were dominated by students and pensioners indicating 27percent of the respondents who were unemployed, among them students were included and pensioners were indicated by 9percent. The overall findings were that there are important differences in behavior regarding the transition from homestead gardening to irrigation farming. Smallholder farmers of Mnquma and Mbhashe municipalities have a great potential in maize, beans, potatoes, pumpkin, butternut production, as well as cattle, sheep, goats, pigs and poultry production. Lastly, the study has highlighted various factors affecting livelihoods sources. Therefore, there is a need for these smallholder farmers to engage consistently with the market to enhance information flow. Extension officers must play a role using the recent extension approach of participatory rural appraisal through discussions with farmers and empower them for marketing problems and solutions. Smallholder farmers must ensure frequent consultation with extension or agricultural advisors for financial and production input support. Government need to strengthen agricultural activities in the rural areas in order to sustain rural livelihoods for rural dwellers. Once the rural economy becomes transformed through agricultural activities then rural dwellers can achieve good standard of living in line with a key macroeconomic objective the South African government. , Thesis (PhD) -- Faculty of Science and Agriculture, 2016
- Full Text:
- Authors: Gidi, Lungile Sivuyile https://orcid.org/0000-0002-2896-2709
- Date: 2016-07
- Subjects: Farms, Small , Irrigation farming -- Economic aspects
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/24906 , vital:63670
- Description: South Africa has implemented several successful rural poverty relief initiatives; however, poverty continues to strain rural development efforts. The aim of the study was to analyse the entrepreneurial development paths and livelihood strategies in smallholder irrigation schemes in the Eastern Cape Province of South Africa. The study has outlined five hypothesizes for the basis of concrete scientific research. Initially the study hypothesizes that a smallholder’s socio-cultural contexts such as village level institutions especially village governance as well as household circumstances including age, education and gender compositions of the household membership as well as household income can determine a smallholder’s transformation ability. The second hypothesis was that alternative economic activities especially farming activities such as livestock and crop production as well as off-farm economic opportunities which were open to a household could influence a smallholder’s willingness to change from homestead gardening to food crop production under government irrigation programme. The third hypothesis was on the smallholder’s assessment of available market for the products of his or her food crop irrigation farming which could be an important consideration in his or her willingness to change. The fourth assumption was that entrepreneurial skills are lacking, in particular the ability to search for opportunities and willingness to do something different than the masses and take risks in that process. Finally, the study hypothesized that the government irrigation scheme governance could determine the attractiveness of the scheme and thereby influencing the willingness of a smallholder to participate. Specifically, the legal and regulatory environments are very restrictive and they are not conducive to effective value and job creation in the villages and for the principal crop and livestock enterprises. The study used cross-sectional data collected from both scheme farmers and non-scheme farmers. There were 107 smallholder farmers administered. Cobb-Douglass production and Multiple Regression Models were used. The results indicated 62 percent were male household head and 38 percent were female household head. The majority of the farmers were above middle age for both men and women households head. Specifically, about 80percent were above 51 years of age. Wage employment on the other hand contributed 8percent for both scheme and non-scheme farmers. The majority of the family members were dominated by students and pensioners indicating 27percent of the respondents who were unemployed, among them students were included and pensioners were indicated by 9percent. The overall findings were that there are important differences in behavior regarding the transition from homestead gardening to irrigation farming. Smallholder farmers of Mnquma and Mbhashe municipalities have a great potential in maize, beans, potatoes, pumpkin, butternut production, as well as cattle, sheep, goats, pigs and poultry production. Lastly, the study has highlighted various factors affecting livelihoods sources. Therefore, there is a need for these smallholder farmers to engage consistently with the market to enhance information flow. Extension officers must play a role using the recent extension approach of participatory rural appraisal through discussions with farmers and empower them for marketing problems and solutions. Smallholder farmers must ensure frequent consultation with extension or agricultural advisors for financial and production input support. Government need to strengthen agricultural activities in the rural areas in order to sustain rural livelihoods for rural dwellers. Once the rural economy becomes transformed through agricultural activities then rural dwellers can achieve good standard of living in line with a key macroeconomic objective the South African government. , Thesis (PhD) -- Faculty of Science and Agriculture, 2016
- Full Text:
Bioconversion of chicken feather into amino acids and keratinase production by mesophilic Chryseobacterium proteolyticum and Pseudomonas aeruginosa isolated from municipal waste dumpsites
- Giwu, Nonkonzo https://orcid.org/0000-0001-9416-7896
- Authors: Giwu, Nonkonzo https://orcid.org/0000-0001-9416-7896
- Date: 2021-02
- Subjects: Poultry -- Processing , Proteolytic enzymes
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22732 , vital:52720
- Description: Chicken feathers are by-products of poultry processing which are generated in large amount because of the global growing demand for poultry meats. They have high contents of crude proteins in the form of keratin which could be valorized into digestible products. Keratinases are classified as a specific collection of proteolytic enzymes that have the ability for the degradation of recalcitrant keratinous substrates. Isolation and characterization of these enzymes from various microbial producers are gaining prominence in recent years due to their industrial and biotechnological application potentials. For this research, the collection of soil samples was done as well as the isolation of bacteria and the screening for keratinolytic activity. 16S rDNA sequencing and phylogenetic analysis were used to identify the isolates with efficient chicken feathers degrading capacity. Optimum conditions for the fermentation prcocess was enhanced for the production of keratinase. The fermentation broth was also analysed for various amino acids of protein, and the biochemical properties of the enzymes were likewise determined. Twenty two (22) bacteria were isolated from the soil samples, and 18 out of the 22 isolates showed proteolytic activity on solid media with diameters of halo zone that ranged from 5 ± 0.71 mm for isolate coded as PSS-03 to 25 ± 1.41 mm for isolate coded as PSS-06. Intact chicken feathers were degraded by proteolytic bacterial isolates in variable degree that ranged from 24percent for PSS-10 and 81percent for DSS-02. Extracellular keratinase production recorded for the isolates ranged from 63.63 ± 4.14 U/mL for PSS-10 to 693.63 ± 62.99 U/mL for DSS-02. Based on 16S rDNA sequence and phylogenetic analysis, the 2 isolates with remarkable keratinolytic activity coded as DSS-02 and PSS-14 were identified as Chryseobacterium proteolyticum FGNn and Pseudomonas aeruginosa GNFx. C. proteolyticum showed the maximum keratinase production of 756.36 U/mL after 72 h of incubation at optimized fermentation conditions which involved initial medium pH (4), incubation temperature (30 oC), inoculum size (2percent; v/v), and chicken feathers (1.5percent; w/v). Similarly, P. aeruginosa optimally produced keratinase (1055.45 U/mL) after 96 h of incubation at optimized fermentation conditions that involved initial medium pH (7-8), incubation temperature (30 oC), inoculum size (5percent; v/v), and chicken feathers (2.5percent; w/v). Furthermore, feather hydrolysate from C. proteolyticum FGNn had relatively higher abundance (>1.5g/100g sample) of arginine (1.85), serine (1.63), glycine (1.9) and lysine (1.62); while P. aeruginosa GNFx feather hydrolysate showed high abundance of arginine, serine, aspartic acid, glutamic acid, glycine, alanine, valine, and leucine with respective concentration of 2.06, 1.67, 2.39, 3.05, 1.87, 1.73, 1.56 and 1.65 (g/100g sample). The results showed that keratinases from the two bacterial isolates were optimally active at pH 8, and temperature of 50 oC for FGNn keratinase and 50-60 oC for GNFx keratinase. The enzymes displayed remarkable pH stability. Keratinase from C. proteolyticum was catalytically inhibited by EDTA and 1,10-phenanthroline but not affected by PMSF; while P. aeruginosa keratinase was not significantly affected by those class of protease inhibitors. Adiitionally, FGNn keratinase demonstrated high residual activity of 90percent, 103percent, 101percent, 110percent, 130, and 105percent in the presence of DTT, hydrogen peroxides, acetonitrile, triton X-100, tween-80 and SDS, respectively. Similarly, catalytic efficiency of GNFx keratinase was promoted in the presence of hydrogen peroxides (119percent), triton X-100 (140percent), tween-80 (150percent) and SDS (147percent) compared to the control. Furthermore, the keratinases from the both bacterial isolates exhibited catalytic efficiency enhancement and remarkable structural stability in the presence of laundry detergents tested. The findings from the study suggest the application potentials of the isolates for the bioconversion of recalcitrant keratinous wastes into digestible and quality protein hydrolysates. The properties of these microbial keratinases indicate that they may be exploited for various biotechnological and industrial processes especially in the formulation of detergents. , Thesis (MSc) -- Faculty of Science and Agriculture, 2021
- Full Text:
- Authors: Giwu, Nonkonzo https://orcid.org/0000-0001-9416-7896
- Date: 2021-02
- Subjects: Poultry -- Processing , Proteolytic enzymes
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22732 , vital:52720
- Description: Chicken feathers are by-products of poultry processing which are generated in large amount because of the global growing demand for poultry meats. They have high contents of crude proteins in the form of keratin which could be valorized into digestible products. Keratinases are classified as a specific collection of proteolytic enzymes that have the ability for the degradation of recalcitrant keratinous substrates. Isolation and characterization of these enzymes from various microbial producers are gaining prominence in recent years due to their industrial and biotechnological application potentials. For this research, the collection of soil samples was done as well as the isolation of bacteria and the screening for keratinolytic activity. 16S rDNA sequencing and phylogenetic analysis were used to identify the isolates with efficient chicken feathers degrading capacity. Optimum conditions for the fermentation prcocess was enhanced for the production of keratinase. The fermentation broth was also analysed for various amino acids of protein, and the biochemical properties of the enzymes were likewise determined. Twenty two (22) bacteria were isolated from the soil samples, and 18 out of the 22 isolates showed proteolytic activity on solid media with diameters of halo zone that ranged from 5 ± 0.71 mm for isolate coded as PSS-03 to 25 ± 1.41 mm for isolate coded as PSS-06. Intact chicken feathers were degraded by proteolytic bacterial isolates in variable degree that ranged from 24percent for PSS-10 and 81percent for DSS-02. Extracellular keratinase production recorded for the isolates ranged from 63.63 ± 4.14 U/mL for PSS-10 to 693.63 ± 62.99 U/mL for DSS-02. Based on 16S rDNA sequence and phylogenetic analysis, the 2 isolates with remarkable keratinolytic activity coded as DSS-02 and PSS-14 were identified as Chryseobacterium proteolyticum FGNn and Pseudomonas aeruginosa GNFx. C. proteolyticum showed the maximum keratinase production of 756.36 U/mL after 72 h of incubation at optimized fermentation conditions which involved initial medium pH (4), incubation temperature (30 oC), inoculum size (2percent; v/v), and chicken feathers (1.5percent; w/v). Similarly, P. aeruginosa optimally produced keratinase (1055.45 U/mL) after 96 h of incubation at optimized fermentation conditions that involved initial medium pH (7-8), incubation temperature (30 oC), inoculum size (5percent; v/v), and chicken feathers (2.5percent; w/v). Furthermore, feather hydrolysate from C. proteolyticum FGNn had relatively higher abundance (>1.5g/100g sample) of arginine (1.85), serine (1.63), glycine (1.9) and lysine (1.62); while P. aeruginosa GNFx feather hydrolysate showed high abundance of arginine, serine, aspartic acid, glutamic acid, glycine, alanine, valine, and leucine with respective concentration of 2.06, 1.67, 2.39, 3.05, 1.87, 1.73, 1.56 and 1.65 (g/100g sample). The results showed that keratinases from the two bacterial isolates were optimally active at pH 8, and temperature of 50 oC for FGNn keratinase and 50-60 oC for GNFx keratinase. The enzymes displayed remarkable pH stability. Keratinase from C. proteolyticum was catalytically inhibited by EDTA and 1,10-phenanthroline but not affected by PMSF; while P. aeruginosa keratinase was not significantly affected by those class of protease inhibitors. Adiitionally, FGNn keratinase demonstrated high residual activity of 90percent, 103percent, 101percent, 110percent, 130, and 105percent in the presence of DTT, hydrogen peroxides, acetonitrile, triton X-100, tween-80 and SDS, respectively. Similarly, catalytic efficiency of GNFx keratinase was promoted in the presence of hydrogen peroxides (119percent), triton X-100 (140percent), tween-80 (150percent) and SDS (147percent) compared to the control. Furthermore, the keratinases from the both bacterial isolates exhibited catalytic efficiency enhancement and remarkable structural stability in the presence of laundry detergents tested. The findings from the study suggest the application potentials of the isolates for the bioconversion of recalcitrant keratinous wastes into digestible and quality protein hydrolysates. The properties of these microbial keratinases indicate that they may be exploited for various biotechnological and industrial processes especially in the formulation of detergents. , Thesis (MSc) -- Faculty of Science and Agriculture, 2021
- Full Text:
In Silico analysis of Spermidine, Spermine and Putrescine interaction with selected heat shock proteins from Plasmodium falciparum 3D7 towards malaria drug development
- Authors: Godlo, Sesethu
- Date: 2022
- Subjects: Heat shock proteins , Malaria vaccine , Plasmodium falciparum
- Language: English
- Type: Master'stheses , text
- Identifier: http://hdl.handle.net/10353/27709 , vital:69395
- Description: Malaria is a mosquito-borne disease that affects around half of the world's population. It is one of the most common parasite infections that endangers human life. One of the most serious issues in malaria therapy is the emergence and spread of antimalarial drug-resistant Plasmodium parasites. This is due to the Plasmodium parasite's constant evolution and development of new methods of surviving medication toxicity. Studies of antimalarial drug development have been focused on polyamine biosynthesis by targeting precursors such as ornithine decarboxylase, adenosylmethionine decarboxylase, and spermidine synthase and protein-protein interactions between Plasmodium falciparum chaperones spotting out Hsp90, Hsp70, and Hsp40 as potential targets with little attention being paid to the interaction between polyamines and molecular chaperones. Therefore, this study seeks to identify interactions between polyamines and molecular chaperones present in the malarial parasite Plasmodium falciparum 3D7. The identification of these interactions might lead to the design of effective drugs to treat and eliminate malaria. Using computational analysis, this study aims to find interactions between polyamines and molecular chaperones found in the malarial parasite Plasmodium falciparum 3D7. The sequences of the selected heat proteins retrieved, and the 3D structures predicted and validated. These structures were docked with polyamines retrieved from PubChem and MD simulations on the docked interactions were performed. Docking revealed common amino acid residues with hydrogen bonds and salt bridges between all receptors and ligands, with glutamine and aspartic acid standing out. MD simulations revealed that when HSP20 and HSP40 transport the ligands, they pop up or are released too quickly. However, HSP60, HSP70, and HSP90 provide optimism since the ligands remain attached to the proteins for a specific amount of time. To further understand and confirm these interactions wet laboratory studies may be carried out in future. , Thesis (MSci) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Authors: Godlo, Sesethu
- Date: 2022
- Subjects: Heat shock proteins , Malaria vaccine , Plasmodium falciparum
- Language: English
- Type: Master'stheses , text
- Identifier: http://hdl.handle.net/10353/27709 , vital:69395
- Description: Malaria is a mosquito-borne disease that affects around half of the world's population. It is one of the most common parasite infections that endangers human life. One of the most serious issues in malaria therapy is the emergence and spread of antimalarial drug-resistant Plasmodium parasites. This is due to the Plasmodium parasite's constant evolution and development of new methods of surviving medication toxicity. Studies of antimalarial drug development have been focused on polyamine biosynthesis by targeting precursors such as ornithine decarboxylase, adenosylmethionine decarboxylase, and spermidine synthase and protein-protein interactions between Plasmodium falciparum chaperones spotting out Hsp90, Hsp70, and Hsp40 as potential targets with little attention being paid to the interaction between polyamines and molecular chaperones. Therefore, this study seeks to identify interactions between polyamines and molecular chaperones present in the malarial parasite Plasmodium falciparum 3D7. The identification of these interactions might lead to the design of effective drugs to treat and eliminate malaria. Using computational analysis, this study aims to find interactions between polyamines and molecular chaperones found in the malarial parasite Plasmodium falciparum 3D7. The sequences of the selected heat proteins retrieved, and the 3D structures predicted and validated. These structures were docked with polyamines retrieved from PubChem and MD simulations on the docked interactions were performed. Docking revealed common amino acid residues with hydrogen bonds and salt bridges between all receptors and ligands, with glutamine and aspartic acid standing out. MD simulations revealed that when HSP20 and HSP40 transport the ligands, they pop up or are released too quickly. However, HSP60, HSP70, and HSP90 provide optimism since the ligands remain attached to the proteins for a specific amount of time. To further understand and confirm these interactions wet laboratory studies may be carried out in future. , Thesis (MSci) -- Faculty of Science and Agriculture, 2022
- Full Text:
Bioinformatic analysis, isolation and kinetic characterisation of red algae (Gelidium capense) dehydrogenases
- Authors: Gogela, Yanga
- Date: 2019
- Subjects: Bioinformatics Chondrus crispus
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/19164 , vital:39878
- Description: Lactate and alcohol dehydrogenases have attracted much attention in various industries and scientific research for their ability to produce chirally pure compounds and be assayed for activity using more straightforward and reproducible assay methods. These enzymes have been previously isolated and purified from various plants, animals and microorganisms. So far, the molecular and biochemical properties of enzymes from these dehydrogenase families in red algae are mostly unknown. Red macroalgae have been used for centuries for the treatment of various diseases and as a source of ingredients in the food industry. The aim of this study was to identify genes in the sequenced red algae genomes that encode dehydrogenases, to use bioinformatic tools to confirm that the proteins encoded are dehydrogenases and to isolate and kinetically purify alcohol or lactate dehydrogenase from red algae species found along the coastline of the Eastern Cape Province. A combination of bioinformatics tools, molecular and biochemical techniques were used to identify, purify, and characterise ADH and LDH enzymes. Bioinformatics analysis revealed two alcohol dehydrogenase genes and two hypothetical genes encoding functional domains similar to D-lactate dehydrogenases from other species. The ADH and LDH-like genes shared low sequence identity at the protein level with medium-chain dehydrogenases/reductases (MDRs) and 2-hydroxy acid dehydrogenases, respectively. These two dehydrogenase genes showed a highly conserved NAD-binding motif (Rossmann-fold) similar to many other NAD-dependent dehydrogenases. The ADH and LDH proteins contained no signal peptides and may be located in the cytoplasm. The phylogenetic tree analysis showed that the two ADH genes belonged to cinnamyl and class III alcohol dehydrogenases, whereas the LDHlike genes were grouped with D-lactate dehydrogenases from other organisms. The ADH and LDH gene family showed cis-acting regulatory elements that are mostly involved in stress response and hormonal response. Structural analysis showed that the dehydrogenases 3D structure predicted models comprise of two domains, namely the substrate binding and the coenzyme binding domains that are rich in beta-strands secondary structure elements. The LDH from red algae was purified approximately 4-fold with a specific activity of 0.044 U/mg. The purified LDH enzyme had a molecular weight of approximately 37kDa. The LDH was active across a broad pH range from 5-9 with a pH optimum observed at 7.5. The LDH ii enzyme in red algae exhibits a temperature optimum of 40 ⁰C and heat stability up to 40 ⁰C. Above 50 °C the LDH activity rapidly decreased showing that the LDH in red algae is not thermostable. The LDH enzyme showed a Km value of 0.8 mM and Vmax of 0.0067 mM.min-1 when using sodium pyruvate as a substrate.
- Full Text:
- Authors: Gogela, Yanga
- Date: 2019
- Subjects: Bioinformatics Chondrus crispus
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/19164 , vital:39878
- Description: Lactate and alcohol dehydrogenases have attracted much attention in various industries and scientific research for their ability to produce chirally pure compounds and be assayed for activity using more straightforward and reproducible assay methods. These enzymes have been previously isolated and purified from various plants, animals and microorganisms. So far, the molecular and biochemical properties of enzymes from these dehydrogenase families in red algae are mostly unknown. Red macroalgae have been used for centuries for the treatment of various diseases and as a source of ingredients in the food industry. The aim of this study was to identify genes in the sequenced red algae genomes that encode dehydrogenases, to use bioinformatic tools to confirm that the proteins encoded are dehydrogenases and to isolate and kinetically purify alcohol or lactate dehydrogenase from red algae species found along the coastline of the Eastern Cape Province. A combination of bioinformatics tools, molecular and biochemical techniques were used to identify, purify, and characterise ADH and LDH enzymes. Bioinformatics analysis revealed two alcohol dehydrogenase genes and two hypothetical genes encoding functional domains similar to D-lactate dehydrogenases from other species. The ADH and LDH-like genes shared low sequence identity at the protein level with medium-chain dehydrogenases/reductases (MDRs) and 2-hydroxy acid dehydrogenases, respectively. These two dehydrogenase genes showed a highly conserved NAD-binding motif (Rossmann-fold) similar to many other NAD-dependent dehydrogenases. The ADH and LDH proteins contained no signal peptides and may be located in the cytoplasm. The phylogenetic tree analysis showed that the two ADH genes belonged to cinnamyl and class III alcohol dehydrogenases, whereas the LDHlike genes were grouped with D-lactate dehydrogenases from other organisms. The ADH and LDH gene family showed cis-acting regulatory elements that are mostly involved in stress response and hormonal response. Structural analysis showed that the dehydrogenases 3D structure predicted models comprise of two domains, namely the substrate binding and the coenzyme binding domains that are rich in beta-strands secondary structure elements. The LDH from red algae was purified approximately 4-fold with a specific activity of 0.044 U/mg. The purified LDH enzyme had a molecular weight of approximately 37kDa. The LDH was active across a broad pH range from 5-9 with a pH optimum observed at 7.5. The LDH ii enzyme in red algae exhibits a temperature optimum of 40 ⁰C and heat stability up to 40 ⁰C. Above 50 °C the LDH activity rapidly decreased showing that the LDH in red algae is not thermostable. The LDH enzyme showed a Km value of 0.8 mM and Vmax of 0.0067 mM.min-1 when using sodium pyruvate as a substrate.
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Assessment of some bacteria species isolated from woodlands of Raymond Mhlaba Local Municipality for high activity laccase production
- Authors: Gogotya, Asemahle
- Date: 2019
- Subjects: Laccase
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: http://hdl.handle.net/10353/19098 , vital:39879
- Description: The function of enzymes in keeping the earth clean is enormous; being executed in the biodegradation of different natural pollutants and biocatalysis of different responses by substituting the ecologically risky and harmful concoction impetuses offering a situation inviting option, laccases is an example of an enzyme described as it doesn’t produce harmful byproducts. Laccases are employed in several industrial processes that play a key responsibility in transformation of life and making the environment a better place. Bacteria have been described as best producers of laccases with a potential in the industrial scale processes. Laccase was produced from different bacterial isolates identified and named as Bacillus sp. strain GFN1 isolated from soil sample, Bacillus sp. strain GLN and Streptomyces sp. strain LAO both isolated from decaying wood samples in Raymond Mhlaba local municipality with accession numbers MK290988 to MK290990 respectively, as identified by partial sequencing, these were the best producers some of which were positive for Napthol and guaiacol; even upon quantitative screening they were better laccase producers. For quantitative laccase screening, 2,2'-azino-bis(3-ethylbenzothiazoline-6- sulphonic acid) was utilised as the substrate for laccase assays. These laccase producing bacteria were subjected to optimization of growth conditions using submerged fermentation which increased the activity of the produced laccase in great amounts. In optimizing basal medium growth conditions where laccase was harvested after every 72 hours where optimal activity was 16 obtained, studying several factors such as pH which turned out to be pH 5 for all isolates, effect of supplemented carbon and nitrogen sources with the be best being lactose and urea respectively with their effective concentrations using lignin as the main carbon and nitrogen source. Copper sulfate was used as the main inducer and the species preferred guaiacol and ferullic acid and the Fe2+ asthe best supplemented metal ion. The time course was done investigating parameters such as cell growth which was determined by observing the optical density, laccase activity, protein concentration and pH and the presented results suggested that when there was an increase in cell growth, enzyme activity decreased pH had no much effect on the enzyme production as it was almost stable all the time with protein concentration exhibiting no direct effect on enzyme activity also. Characterization of the crude enzyme was done to check the stability of the enzyme produced in various parameters. The enzymes produced by the different strains were thermophilic as they were able to withstand elevated temperatures between 90 and 100 C, with pH stability within an extensive variety of alkaline pH, typical of most bacterial laccases. Various metal ions affected the stability of the enzyme with CuSO4 increasing the stability of two of the bacterial enzyme and appeared to slightly decrease the stability of one enzyme. The studied inhibitors only decreased the stability on the enzyme and couldn’t completely inhibit the enzyme, and the enzymes showed specificity towards varying substrates. The studied bacterial laccases exhibit tremendous characteristics which are of great significance in the industries and will add to the novelty of bacterial laccases and their stability amongst the most studied fungal laccases.
- Full Text:
- Authors: Gogotya, Asemahle
- Date: 2019
- Subjects: Laccase
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: http://hdl.handle.net/10353/19098 , vital:39879
- Description: The function of enzymes in keeping the earth clean is enormous; being executed in the biodegradation of different natural pollutants and biocatalysis of different responses by substituting the ecologically risky and harmful concoction impetuses offering a situation inviting option, laccases is an example of an enzyme described as it doesn’t produce harmful byproducts. Laccases are employed in several industrial processes that play a key responsibility in transformation of life and making the environment a better place. Bacteria have been described as best producers of laccases with a potential in the industrial scale processes. Laccase was produced from different bacterial isolates identified and named as Bacillus sp. strain GFN1 isolated from soil sample, Bacillus sp. strain GLN and Streptomyces sp. strain LAO both isolated from decaying wood samples in Raymond Mhlaba local municipality with accession numbers MK290988 to MK290990 respectively, as identified by partial sequencing, these were the best producers some of which were positive for Napthol and guaiacol; even upon quantitative screening they were better laccase producers. For quantitative laccase screening, 2,2'-azino-bis(3-ethylbenzothiazoline-6- sulphonic acid) was utilised as the substrate for laccase assays. These laccase producing bacteria were subjected to optimization of growth conditions using submerged fermentation which increased the activity of the produced laccase in great amounts. In optimizing basal medium growth conditions where laccase was harvested after every 72 hours where optimal activity was 16 obtained, studying several factors such as pH which turned out to be pH 5 for all isolates, effect of supplemented carbon and nitrogen sources with the be best being lactose and urea respectively with their effective concentrations using lignin as the main carbon and nitrogen source. Copper sulfate was used as the main inducer and the species preferred guaiacol and ferullic acid and the Fe2+ asthe best supplemented metal ion. The time course was done investigating parameters such as cell growth which was determined by observing the optical density, laccase activity, protein concentration and pH and the presented results suggested that when there was an increase in cell growth, enzyme activity decreased pH had no much effect on the enzyme production as it was almost stable all the time with protein concentration exhibiting no direct effect on enzyme activity also. Characterization of the crude enzyme was done to check the stability of the enzyme produced in various parameters. The enzymes produced by the different strains were thermophilic as they were able to withstand elevated temperatures between 90 and 100 C, with pH stability within an extensive variety of alkaline pH, typical of most bacterial laccases. Various metal ions affected the stability of the enzyme with CuSO4 increasing the stability of two of the bacterial enzyme and appeared to slightly decrease the stability of one enzyme. The studied inhibitors only decreased the stability on the enzyme and couldn’t completely inhibit the enzyme, and the enzymes showed specificity towards varying substrates. The studied bacterial laccases exhibit tremendous characteristics which are of great significance in the industries and will add to the novelty of bacterial laccases and their stability amongst the most studied fungal laccases.
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Comparative analysis of zero-tillage and conventional tillage practices in the Amahlathi local municipality of the Eastern Cape province of South Africa
- Authors: Gomo, Zintle
- Date: 2017
- Subjects: Tillage--South Africa--Eastern Cape Farms, Small--South Africa--Eastern Cape No-tillage--South Africa--Eastern Cape
- Language: English
- Type: Thesis , Masters , Agricultural Economics
- Identifier: http://hdl.handle.net/10353/11586 , vital:39087
- Description: The current interest in zero tillage/no-till technologies is a result of the need to reduce excessive land degradation in most crop producing areas as well as to enhance sustainable food production. Farmers are always looking for ways to increase yields and profits and zero-tillage may be a way to achieve this goal. However, a systematic comparative study of the performance of zero-tillage and conventional tillage within the former homeland areas of the Eastern Cape Province is lacking. The broad objective of the study is to comparatively analyze zero tillage and conventional tillage and to determine which practice is more beneficial for the land and farmers in the area. Specifically, the study investigated the relative performance of Zero-tillage and conventional–tillage in terms of quantity produced per farm and per hectare, factors influencing the adoption rate of zero tillage and conventional tillage and to determine the relative impact of zero-tillage and conventional tillage on household income. The study was carried out in Amahlathi Local Municipality in the Eastern Cape Province and employed survey data obtained from 100 respondents using conventional tillage and zero tillage farmers growing spinach, cabbage, beetroot, maize, and potatoes. The study employed a cross-sectional research design. A multistage stratified sampling procedure was used in which the first stage involved selecting respondents from Amahlathi Local Municipally. This was followed by the selection of villages and then the respondents. This was done through stratification of smallholder farmers from the different Villages. This was followed by random sampling which was used to get the sample size for the study. Stata and SPSS were used to analyze the data. Descriptive statistics was used to examine current farming practices in the Eastern Cape Province while Propensity Score Matching was employed to estimate the factors that had an impact on zero tillage adoption as well as the relative impact of zero tillage and conventional tillage on household income. Gross margin analysis was used to estimate profitability of zero tillage and conventional. female farmers are participating more in zero tillage with 63.8percent while males are dominating the conventional tillage with 51.6percent. These results show that females play a crucial role in decision making when it comes to agriculture and adoption of new agricultural technologies. The majority of the farmers involved in the study were young farmers with 58percent from zero tillage and 42percent practically involved in conventional tillage. Moreover, the study showed that 41percent of the respondents practising ZT were married, and about 39percent of the respondents practising conventional tillage were married. The marital status of the respondents suggested that zero-tillage farmers were relatively stable in their farming activities as compared to conventional tillage. The results presented that 52.2percent of the respondents who practised zero tillage were better educated than the 48.4percent of the respondents practising conventional tillage. The respondents that were specialising in zero-tillage, about 41% relied on farming, 6% relied on salaried income and 54percent relied on social grants. On the other hand, respondents that were specialising in conventional tillage about, 26percent relied on farming, 16percent relied on salaried income, while 58percent relied on social grants. The respondents that were specialising in zero-tillage, about 28percent used communal land, 1percent used own land and 71percent used family land. On the other hand, respondents that were specialising in conventional tillage about, 42percent used communal land, 7percent use own land and 52percent used family land. The average household size for both groups of farmers is 5 people per household. Household income distribution for conventional tillage is giving the farmers an average of R3187.10 income while the zero tillage is giving them an income of R2305.80 on average. The study revealed that the landholdings for conventional tillage agriculture tend to be more (1.77 ha) compared to zero tillage (0.79 ha) agriculture. The Propensity Score Matching results indicated that participation in smallholder zero tillage farming contributes to household income. This implies that participating in zero tillage farming can contribute to rural livelihoods, increased income and production yields. The study results showed that households chose different farming systems based on their knowledge, level of education and farming experiences. The gross margin results show that conventional tillage farming households generated more income than zero tillage farming households. Farmers who were involved in conventional tillage farming were complaining that yields and income have decreased with time and they are continuing to decrease while farmers who carried out zero tillage farming indicated that their yields and income have improved considerably and continue to increase with time. Thus, support for adopting and implementing zero tillage practices can be an important factor for improving incomes for rural households. Based on the findings highlighted above, the study recommends provision of farm inputs and continuation of government support with more emphasis on strengthening access to inputs and technical assistance. There is a need for support programmes that would help to motivate farmers for better performance. The programmes include infrastructure developments, research and extension activities.
- Full Text:
- Authors: Gomo, Zintle
- Date: 2017
- Subjects: Tillage--South Africa--Eastern Cape Farms, Small--South Africa--Eastern Cape No-tillage--South Africa--Eastern Cape
- Language: English
- Type: Thesis , Masters , Agricultural Economics
- Identifier: http://hdl.handle.net/10353/11586 , vital:39087
- Description: The current interest in zero tillage/no-till technologies is a result of the need to reduce excessive land degradation in most crop producing areas as well as to enhance sustainable food production. Farmers are always looking for ways to increase yields and profits and zero-tillage may be a way to achieve this goal. However, a systematic comparative study of the performance of zero-tillage and conventional tillage within the former homeland areas of the Eastern Cape Province is lacking. The broad objective of the study is to comparatively analyze zero tillage and conventional tillage and to determine which practice is more beneficial for the land and farmers in the area. Specifically, the study investigated the relative performance of Zero-tillage and conventional–tillage in terms of quantity produced per farm and per hectare, factors influencing the adoption rate of zero tillage and conventional tillage and to determine the relative impact of zero-tillage and conventional tillage on household income. The study was carried out in Amahlathi Local Municipality in the Eastern Cape Province and employed survey data obtained from 100 respondents using conventional tillage and zero tillage farmers growing spinach, cabbage, beetroot, maize, and potatoes. The study employed a cross-sectional research design. A multistage stratified sampling procedure was used in which the first stage involved selecting respondents from Amahlathi Local Municipally. This was followed by the selection of villages and then the respondents. This was done through stratification of smallholder farmers from the different Villages. This was followed by random sampling which was used to get the sample size for the study. Stata and SPSS were used to analyze the data. Descriptive statistics was used to examine current farming practices in the Eastern Cape Province while Propensity Score Matching was employed to estimate the factors that had an impact on zero tillage adoption as well as the relative impact of zero tillage and conventional tillage on household income. Gross margin analysis was used to estimate profitability of zero tillage and conventional. female farmers are participating more in zero tillage with 63.8percent while males are dominating the conventional tillage with 51.6percent. These results show that females play a crucial role in decision making when it comes to agriculture and adoption of new agricultural technologies. The majority of the farmers involved in the study were young farmers with 58percent from zero tillage and 42percent practically involved in conventional tillage. Moreover, the study showed that 41percent of the respondents practising ZT were married, and about 39percent of the respondents practising conventional tillage were married. The marital status of the respondents suggested that zero-tillage farmers were relatively stable in their farming activities as compared to conventional tillage. The results presented that 52.2percent of the respondents who practised zero tillage were better educated than the 48.4percent of the respondents practising conventional tillage. The respondents that were specialising in zero-tillage, about 41% relied on farming, 6% relied on salaried income and 54percent relied on social grants. On the other hand, respondents that were specialising in conventional tillage about, 26percent relied on farming, 16percent relied on salaried income, while 58percent relied on social grants. The respondents that were specialising in zero-tillage, about 28percent used communal land, 1percent used own land and 71percent used family land. On the other hand, respondents that were specialising in conventional tillage about, 42percent used communal land, 7percent use own land and 52percent used family land. The average household size for both groups of farmers is 5 people per household. Household income distribution for conventional tillage is giving the farmers an average of R3187.10 income while the zero tillage is giving them an income of R2305.80 on average. The study revealed that the landholdings for conventional tillage agriculture tend to be more (1.77 ha) compared to zero tillage (0.79 ha) agriculture. The Propensity Score Matching results indicated that participation in smallholder zero tillage farming contributes to household income. This implies that participating in zero tillage farming can contribute to rural livelihoods, increased income and production yields. The study results showed that households chose different farming systems based on their knowledge, level of education and farming experiences. The gross margin results show that conventional tillage farming households generated more income than zero tillage farming households. Farmers who were involved in conventional tillage farming were complaining that yields and income have decreased with time and they are continuing to decrease while farmers who carried out zero tillage farming indicated that their yields and income have improved considerably and continue to increase with time. Thus, support for adopting and implementing zero tillage practices can be an important factor for improving incomes for rural households. Based on the findings highlighted above, the study recommends provision of farm inputs and continuation of government support with more emphasis on strengthening access to inputs and technical assistance. There is a need for support programmes that would help to motivate farmers for better performance. The programmes include infrastructure developments, research and extension activities.
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The string vibrator experiment-experimental and analytical determination of system fundamental natural frequencies
- Authors: Gordon, Mark Leonard
- Date: 2011-11
- Subjects: Vibration , Nonlinear oscillations , Waves
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/24002 , vital:62245
- Description: This thesis represents an experimental and intellectual journey of more than three years. The String Vibrator Experiment (SVE) is an experimental payload on the SumbandilaSat, satellite. The experiment was initially designed to compare low-earthorbitstretched string nonlinear dynamics with those found terrestrially, with particular emphasis on the effects of micro-gravity and near vacuum. Due to the damage of some internal components of the SVE, the terrestrial experiment had to be characterized by finding both transverse fundamental natural frequencies and the longitudinal system fundamental natural frequency. Forced and free vibration tests were performed on the SVE, with comparable results. The percentage frequency difference between measurement results obtained for the said natural frequencies was found to be acceptable. An analytical model for the string longitudinal system was developed using Energy Methods, assuming linear coupling of the stretched string and the flexible support. Bessel Functions were used to find the natural frequency of the flexible support, which is made of a thin-circular plate loaded centrally by the stretched string and fixed on its outer boundary. The natural frequency thus predicted, corresponds closely with that measured by Laser Doppler Vibrometry. It was found that the longitudinal system behaves in an uncoupled, manner. In this study use was made of piezo bi-morph sensors as vibration measuring devices, with promising results. A method called the peak amplitude discrimination method is introduced to find the respective resonant frequencies; this method is an adaptation of the sweptsine frequency method Nonlinear behavior of the SVE was found to exist exhibiting Sub-harmonics, Super-harmonics, Combination harmonics and Internal Resonances. It is hoped that the experimental methods used in this study would aid in the measurement and analysis of longitudinal vibrations found in flexible cables, rods and rigid bars. , Thesis (PhD) -- Faculty of Science and Agriculture, 2011
- Full Text:
- Authors: Gordon, Mark Leonard
- Date: 2011-11
- Subjects: Vibration , Nonlinear oscillations , Waves
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/24002 , vital:62245
- Description: This thesis represents an experimental and intellectual journey of more than three years. The String Vibrator Experiment (SVE) is an experimental payload on the SumbandilaSat, satellite. The experiment was initially designed to compare low-earthorbitstretched string nonlinear dynamics with those found terrestrially, with particular emphasis on the effects of micro-gravity and near vacuum. Due to the damage of some internal components of the SVE, the terrestrial experiment had to be characterized by finding both transverse fundamental natural frequencies and the longitudinal system fundamental natural frequency. Forced and free vibration tests were performed on the SVE, with comparable results. The percentage frequency difference between measurement results obtained for the said natural frequencies was found to be acceptable. An analytical model for the string longitudinal system was developed using Energy Methods, assuming linear coupling of the stretched string and the flexible support. Bessel Functions were used to find the natural frequency of the flexible support, which is made of a thin-circular plate loaded centrally by the stretched string and fixed on its outer boundary. The natural frequency thus predicted, corresponds closely with that measured by Laser Doppler Vibrometry. It was found that the longitudinal system behaves in an uncoupled, manner. In this study use was made of piezo bi-morph sensors as vibration measuring devices, with promising results. A method called the peak amplitude discrimination method is introduced to find the respective resonant frequencies; this method is an adaptation of the sweptsine frequency method Nonlinear behavior of the SVE was found to exist exhibiting Sub-harmonics, Super-harmonics, Combination harmonics and Internal Resonances. It is hoped that the experimental methods used in this study would aid in the measurement and analysis of longitudinal vibrations found in flexible cables, rods and rigid bars. , Thesis (PhD) -- Faculty of Science and Agriculture, 2011
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Investigation of strategies employed in rural households to improve food security in Raymond Mhlaba Local Municipality : a case of Zihlahleni Location in Middledrift, Eastern Cape Province
- Authors: Gqozo, Odwa
- Date: 2018
- Subjects: Food security -- South Africa -- Eastern Cape Rural development -- South Africa -- Eastern Cape Households -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/10758 , vital:35752
- Description: Eastern Cape is one of the provinces experiencing a rapid increase in food prices while household income is increasing at a slower rate. Against this background, the main objective of this study was to investigate strategies used by rural households to improve food security in Raymond Mhlaba Local Municipality formally known as Nkonkobe in the Eastern Cape Province, South Africa. Data were collected from 100 households using a questionnaire as the main instrument by using simple random sampling. Data were analyzed by employing simple descriptive statistics to describe household food security. Results revealed that most (50.3percent) households that were interviewed were male headed and unemployment was high (73.6percent). Moreover, the average age of the interviewed household heads was 59 years. Most (68percent) of the households owned home gardens and had access to arable land which was not being cultivated. Most (87percent) households indicated that lack of capital was the main cause of food security and depended on government grants. Most (100percent) of the interviewed household heads depend mostly on food purchases rather than their own production. The recommendation is that the government should continue fostering its agenda of improving agriculture as a strategy in rural households for curbing food insecurity.
- Full Text:
- Authors: Gqozo, Odwa
- Date: 2018
- Subjects: Food security -- South Africa -- Eastern Cape Rural development -- South Africa -- Eastern Cape Households -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/10758 , vital:35752
- Description: Eastern Cape is one of the provinces experiencing a rapid increase in food prices while household income is increasing at a slower rate. Against this background, the main objective of this study was to investigate strategies used by rural households to improve food security in Raymond Mhlaba Local Municipality formally known as Nkonkobe in the Eastern Cape Province, South Africa. Data were collected from 100 households using a questionnaire as the main instrument by using simple random sampling. Data were analyzed by employing simple descriptive statistics to describe household food security. Results revealed that most (50.3percent) households that were interviewed were male headed and unemployment was high (73.6percent). Moreover, the average age of the interviewed household heads was 59 years. Most (68percent) of the households owned home gardens and had access to arable land which was not being cultivated. Most (87percent) households indicated that lack of capital was the main cause of food security and depended on government grants. Most (100percent) of the interviewed household heads depend mostly on food purchases rather than their own production. The recommendation is that the government should continue fostering its agenda of improving agriculture as a strategy in rural households for curbing food insecurity.
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An assessment of public support given to land reform commonage farmers by local and provincial government and their perfomance: A case study of Makana Local Municipality in Eastern Cape
- Authors: Gqweta, N V P
- Date: 2016
- Subjects: Land reform -- South Africa , Land use
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/23991 , vital:62238
- Description: Access to land is very important for previously disadvantage people from the countries where agriculture is one of the main sources for employment in order to improve their livelihoods. Worldwide, Land Reform arose mainly because of inequalities of resources. In South Africa the Land Reform started in as early as 1658 where blacks were not afforded equal opportunities as white people and therefore off farm land and properties. When South Africa’s first democratic government came into power in 1994, one of its goals was to redress the injustice of the past and give back land to the previously disadvantaged people through various land reform programmes. One of the components of the land reform programme was the provision of commonages lands to urban municipalities for use by the urban poor. The Department of Rural Development and Land Reform acquired commonages land for the municipalities for the purpose of agricultural production. The study focused on the Municipal Commonage Programme and this has been done by assessing the public support given to land reform commonage farmers by local and provincial government and their performance in Makana Local Municipality in Eastern Cape. The study showed that land reform commonage emerging farmers are confronted by numerous challenges such as poor infrastructure, access to markets, mentorship, credit, transport by beneficiaries, lack of support from government departments and lack of co-ordination between government departments. These and other challenges ultimately hamper beneficiaries from making effective use of land. The study was done on eight commonages in Makana Municipality. The data was analyzed using Statistical Package for the Social Science (SPSS) and Microsoft Excel. Data collection entailed questionnaire, interviews and focus group discussions. In view of the challenges for commonage farmers, this study provides recommendation for improving the commonage land reform redistribution projects. Current management attempts are not ensuring the efficient equitable and sustainable use of these commonages. Municipal Commonage should be better integrated into agrarian reform through leases and an efficient Commonage Farmers Support Programmes. , Thesis (MSc) -- Faculty of Science and Agriculture, 2016
- Full Text:
- Authors: Gqweta, N V P
- Date: 2016
- Subjects: Land reform -- South Africa , Land use
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/23991 , vital:62238
- Description: Access to land is very important for previously disadvantage people from the countries where agriculture is one of the main sources for employment in order to improve their livelihoods. Worldwide, Land Reform arose mainly because of inequalities of resources. In South Africa the Land Reform started in as early as 1658 where blacks were not afforded equal opportunities as white people and therefore off farm land and properties. When South Africa’s first democratic government came into power in 1994, one of its goals was to redress the injustice of the past and give back land to the previously disadvantaged people through various land reform programmes. One of the components of the land reform programme was the provision of commonages lands to urban municipalities for use by the urban poor. The Department of Rural Development and Land Reform acquired commonages land for the municipalities for the purpose of agricultural production. The study focused on the Municipal Commonage Programme and this has been done by assessing the public support given to land reform commonage farmers by local and provincial government and their performance in Makana Local Municipality in Eastern Cape. The study showed that land reform commonage emerging farmers are confronted by numerous challenges such as poor infrastructure, access to markets, mentorship, credit, transport by beneficiaries, lack of support from government departments and lack of co-ordination between government departments. These and other challenges ultimately hamper beneficiaries from making effective use of land. The study was done on eight commonages in Makana Municipality. The data was analyzed using Statistical Package for the Social Science (SPSS) and Microsoft Excel. Data collection entailed questionnaire, interviews and focus group discussions. In view of the challenges for commonage farmers, this study provides recommendation for improving the commonage land reform redistribution projects. Current management attempts are not ensuring the efficient equitable and sustainable use of these commonages. Municipal Commonage should be better integrated into agrarian reform through leases and an efficient Commonage Farmers Support Programmes. , Thesis (MSc) -- Faculty of Science and Agriculture, 2016
- Full Text:
Development of an Extensible Framework for Easy Implementation of Image Processing Applications on Android Operating System
- Authors: Gunu, Bulelani
- Date: 2019
- Subjects: Operating systems (Computers)
- Language: English
- Type: Thesis , Masters , MSc (Computer Science )
- Identifier: http://hdl.handle.net/10353/17201 , vital:40865
- Description: Image processing is a field that has been in existence for many years and it continues to grow with many other research areas adopting its use. One such research area is the area of mobile devices. Mobile devices have been equipped with image processing software and hardware so as to apply image processing features. While there are many applications of image processing and new applications have been developed, there are still many functionalities that these image processing software perform the same. The development of these software from scratch requires a lot of effort and can be time consuming. This becomes even worse for mobile device application developers, specifically Android developers, who have no knowledge of implementing image processing functionalities. This project offers a software framework which allows Android application developers to focus on their unique requirements while incorporating image processing features into their applications. The framework provides the common image processing functionalities and Android developers do not need to know the internal working of the framework in order to use it. This helps reduce application development time and effort. The framework also offers an extensibility feature which takes into consideration the future growth. This means that third party developers can keep the framework up to date with the technological advancements. The presented framework is shown to be requiring less technical expertise. Also, the way in which the system is design makes it easy to understand. This design can be adopted for other related projects that require extensible frameworks for the Android operating system.
- Full Text:
- Authors: Gunu, Bulelani
- Date: 2019
- Subjects: Operating systems (Computers)
- Language: English
- Type: Thesis , Masters , MSc (Computer Science )
- Identifier: http://hdl.handle.net/10353/17201 , vital:40865
- Description: Image processing is a field that has been in existence for many years and it continues to grow with many other research areas adopting its use. One such research area is the area of mobile devices. Mobile devices have been equipped with image processing software and hardware so as to apply image processing features. While there are many applications of image processing and new applications have been developed, there are still many functionalities that these image processing software perform the same. The development of these software from scratch requires a lot of effort and can be time consuming. This becomes even worse for mobile device application developers, specifically Android developers, who have no knowledge of implementing image processing functionalities. This project offers a software framework which allows Android application developers to focus on their unique requirements while incorporating image processing features into their applications. The framework provides the common image processing functionalities and Android developers do not need to know the internal working of the framework in order to use it. This helps reduce application development time and effort. The framework also offers an extensibility feature which takes into consideration the future growth. This means that third party developers can keep the framework up to date with the technological advancements. The presented framework is shown to be requiring less technical expertise. Also, the way in which the system is design makes it easy to understand. This design can be adopted for other related projects that require extensible frameworks for the Android operating system.
- Full Text:
Investigation of the NFC technology for mobile payments and the development of a prototype payment application in the context of marginalized rural areas
- Authors: Gurajena, Caroline
- Date: 2014
- Subjects: Mobile commerce -- South Africa Mobile communication systems -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/14071 , vital:39802
- Description: The Internet of Things (IoT) environment involves the interaction of numerous ‘things’. These ‘things’ are embedded with different kinds of technologies such as RFID technology, NFC technology and sensors. This causes IoT to bring into play many security risks apart from the ones that already exist in the current Internet, for example, embedded RFID tags can be easily triggered and send their content which could be private information. IoT also introduces internal attacks such as on-off attack, bad mouthing and white washing attacks into networks that already exist. These internal attacks cannot be solved by hard security mechanisms such as cryptographic algorithms and firewalls because they guarantee total trust. This eliminates uncertainty which should always be available where trust exist. That is, hard security mechanisms enable IoT ‘things’ to either trust another ‘thing’ completely or not and this makes them unsuitable for the IoT environment. When objects in any network are communicating, there is some element of uncertainty. Also, hard security mechanisms such as public key cryptography cause communication overheard in the already resource-constrained IoT devices and these conventional cryptography methods cannot deal with internal attacks. This brings about the need for a middleware that includes functions that will manage trust, privacy and security issues of all data exchange, communications and network connections. For IoT to be successful, the provision of trust, security and privacy measures are essential. Trust management may enhance the adoption and security measures in IoT. Trust helps in identifying trustworthy ‘things’ in the network and give ‘things’ in the network the ability to reason in all aspects concerning trust in the environment. Trust can be administered through a trust management model. This research notes that most of the trust models that have been proposed fail to address scalability challenges and lack suitable computation methods. It is on that premise that this research focuses on developing a suitable trust model for the IoT environment. The research also introduces new ways of creating relationships in IoT. This enables the creation of new cooperation opportunities in the environment. In overall, this research aimed to design and develop a generic trust and authority delegation model for the heterogonous IoT environment that is scalable and generalized to cater for the heterogeneous IoT environment. This research was conducted in three phases. The first phase reviewed literature in order to identify outstanding issues in IoT trust management and also identify the suitable computational method. This provided a critical analysis of different computational methods highlighting their advantages and limitations. In the second phase of the research, the proposed trust model was designed and tested. In the last phase, the feasibility of the proposed model was evaluated. The proposed model is based on fuzzy logic. Fuzzy logic was selected for trust computation because it is able to imitate the process of the human mind through the use of linguistic variables and it can handle uncertainty. The proposed model was tested in a simulated environment. The simulation results showed that the proposed model can identify selfish and malicious entities effectively. The results also showed that the model was able to deal with different types of behaviours of entities. The testing proved that the proposed trust model can support decision making in IoT based on trust. The results from the evaluation show that this research ameliorates the design and development of trust management solutions for the IoT environment.
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- Authors: Gurajena, Caroline
- Date: 2014
- Subjects: Mobile commerce -- South Africa Mobile communication systems -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/14071 , vital:39802
- Description: The Internet of Things (IoT) environment involves the interaction of numerous ‘things’. These ‘things’ are embedded with different kinds of technologies such as RFID technology, NFC technology and sensors. This causes IoT to bring into play many security risks apart from the ones that already exist in the current Internet, for example, embedded RFID tags can be easily triggered and send their content which could be private information. IoT also introduces internal attacks such as on-off attack, bad mouthing and white washing attacks into networks that already exist. These internal attacks cannot be solved by hard security mechanisms such as cryptographic algorithms and firewalls because they guarantee total trust. This eliminates uncertainty which should always be available where trust exist. That is, hard security mechanisms enable IoT ‘things’ to either trust another ‘thing’ completely or not and this makes them unsuitable for the IoT environment. When objects in any network are communicating, there is some element of uncertainty. Also, hard security mechanisms such as public key cryptography cause communication overheard in the already resource-constrained IoT devices and these conventional cryptography methods cannot deal with internal attacks. This brings about the need for a middleware that includes functions that will manage trust, privacy and security issues of all data exchange, communications and network connections. For IoT to be successful, the provision of trust, security and privacy measures are essential. Trust management may enhance the adoption and security measures in IoT. Trust helps in identifying trustworthy ‘things’ in the network and give ‘things’ in the network the ability to reason in all aspects concerning trust in the environment. Trust can be administered through a trust management model. This research notes that most of the trust models that have been proposed fail to address scalability challenges and lack suitable computation methods. It is on that premise that this research focuses on developing a suitable trust model for the IoT environment. The research also introduces new ways of creating relationships in IoT. This enables the creation of new cooperation opportunities in the environment. In overall, this research aimed to design and develop a generic trust and authority delegation model for the heterogonous IoT environment that is scalable and generalized to cater for the heterogeneous IoT environment. This research was conducted in three phases. The first phase reviewed literature in order to identify outstanding issues in IoT trust management and also identify the suitable computational method. This provided a critical analysis of different computational methods highlighting their advantages and limitations. In the second phase of the research, the proposed trust model was designed and tested. In the last phase, the feasibility of the proposed model was evaluated. The proposed model is based on fuzzy logic. Fuzzy logic was selected for trust computation because it is able to imitate the process of the human mind through the use of linguistic variables and it can handle uncertainty. The proposed model was tested in a simulated environment. The simulation results showed that the proposed model can identify selfish and malicious entities effectively. The results also showed that the model was able to deal with different types of behaviours of entities. The testing proved that the proposed trust model can support decision making in IoT based on trust. The results from the evaluation show that this research ameliorates the design and development of trust management solutions for the IoT environment.
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Dynamic Mathematical Modeling in Chemical Reaction Networks
- Authors: Gurajena, Simba
- Date: 2018
- Subjects: Chemical reaction
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/11961 , vital:39122
- Description: Many students are familiar with the idea of ecological, financial modeling and modeling in other fields, but modeling in engineering fields is still an area to be looked at. In this discussion the researcher will deal with chemical reaction networks. This will cover areas in chemical reaction, interaction diagrams and the associated models. The discussion will also cover dynamic behaviour of reaction networks. The law of mass action and examples of simple networks will be dealt with. Differential equation models of biochemical and genetic systems are invariantly nonlinear, and as such numerical simulation is used to solve such models. The use of numerical simulation packages will be discussed and separation of timescale and model reduction will form part of the discussion.
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- Authors: Gurajena, Simba
- Date: 2018
- Subjects: Chemical reaction
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/11961 , vital:39122
- Description: Many students are familiar with the idea of ecological, financial modeling and modeling in other fields, but modeling in engineering fields is still an area to be looked at. In this discussion the researcher will deal with chemical reaction networks. This will cover areas in chemical reaction, interaction diagrams and the associated models. The discussion will also cover dynamic behaviour of reaction networks. The law of mass action and examples of simple networks will be dealt with. Differential equation models of biochemical and genetic systems are invariantly nonlinear, and as such numerical simulation is used to solve such models. The use of numerical simulation packages will be discussed and separation of timescale and model reduction will form part of the discussion.
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Woody encroachment and plant-root soil interactions in a semi-arid savanna
- Authors: Gusha, Bukho
- Date: 2015
- Subjects: Pastures -- Management Weeds Invasive plants
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12139 , vital:39174
- Description: Savannas occupy 1/8 of the global land surface, support a large proportion of the world’s human population and the majority of its rangeland and livestock. Woody encroachment has been reported as the major challenge in these landscapes. This study describes the differences between three contrasting tree density classes in a semi- arid savanna with the view to developing an improved understanding of woody encroachment which is prevalent in this region. The study attempted to determine if there was a relationship between lateral root distributions at varying soil depths with increasing levels of woody encroachment, and to compare species composition and soil water profiles in these rangelands. Three homogeneous vegetation units, namely: sparsely encroached (HVU1), grassland (HVU2) and Albany thicket (HVU3) were identified for the study sites. A Trench method was used determine root biomass and a step point method was used to determine herbaceous species composition in all the HVUs. The results showed that more Decreaser species (especially Themeda triandra) were recorded in a sparsely encroached site (HVU1) and grassland site (HVU2), while Cynodon dactylon was mostly recorded in the thicket site (HVU3). Acacia karroo was mostly recorded in HVU1 while in HVU2 other woody species such as Coddia rudis and Grewia occidentalis were also recoded. HVU3 had the poorest basal cover (point to tuft distance) (22.60 cm) while HVU1 (9.93 cm) and HVU2 (7.73 cm) had moderate basal cover. The herbaceous standing biomass was significantly different across the HVUs. HVU3 was higher (1206.15 kg ha-1) than HVU1 (942.43 kg ha-1) and HVU2 (677.10 kg ha-1). The soil moisture content was significantly different between the HVUs, but was not significantly different between the depths (p< 0.05). High soil moisture content was recorded in HVU3 compared to other HVUs. The results of Analysis of Variance (ANOVA) showed that soil depth and the type of homogenous vegetation unit (HVU) had significant effects (p<0.01) on root biomass. The pair wise t-test showed that there were no significant difference in root biomass between sparsely encroached (HVU1) and grassland (HVU2) sites (p>0.05), but there were significant differences in root biomass between grassland (HVU2) and thicket (HVU3) site (p<0.05). The mean for total root biomass found in the study was 2.66 kg m-2. In all the trenches most of the root biomass was found in depth 1 (0-30 cm) which was 2.43 kg m-2followed by 1.32 kg m-2 in depth 2 (30-60 cm) and 0.49 kg m-2 in depth 3 (60-90 cm). According to the results on species composition, herbaceous biomass, basal cover, soil moisture content and the root biomass, Kwezana communal rangeland has a potential of running a sustainable livestock production enterprise if proper management practices can be implemented. To improve the rangelands of Kwezana communal rangelands, management such as proper resting, burning, proper stocking rates and physically clearing of bushes should be considered.
- Full Text:
- Authors: Gusha, Bukho
- Date: 2015
- Subjects: Pastures -- Management Weeds Invasive plants
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12139 , vital:39174
- Description: Savannas occupy 1/8 of the global land surface, support a large proportion of the world’s human population and the majority of its rangeland and livestock. Woody encroachment has been reported as the major challenge in these landscapes. This study describes the differences between three contrasting tree density classes in a semi- arid savanna with the view to developing an improved understanding of woody encroachment which is prevalent in this region. The study attempted to determine if there was a relationship between lateral root distributions at varying soil depths with increasing levels of woody encroachment, and to compare species composition and soil water profiles in these rangelands. Three homogeneous vegetation units, namely: sparsely encroached (HVU1), grassland (HVU2) and Albany thicket (HVU3) were identified for the study sites. A Trench method was used determine root biomass and a step point method was used to determine herbaceous species composition in all the HVUs. The results showed that more Decreaser species (especially Themeda triandra) were recorded in a sparsely encroached site (HVU1) and grassland site (HVU2), while Cynodon dactylon was mostly recorded in the thicket site (HVU3). Acacia karroo was mostly recorded in HVU1 while in HVU2 other woody species such as Coddia rudis and Grewia occidentalis were also recoded. HVU3 had the poorest basal cover (point to tuft distance) (22.60 cm) while HVU1 (9.93 cm) and HVU2 (7.73 cm) had moderate basal cover. The herbaceous standing biomass was significantly different across the HVUs. HVU3 was higher (1206.15 kg ha-1) than HVU1 (942.43 kg ha-1) and HVU2 (677.10 kg ha-1). The soil moisture content was significantly different between the HVUs, but was not significantly different between the depths (p< 0.05). High soil moisture content was recorded in HVU3 compared to other HVUs. The results of Analysis of Variance (ANOVA) showed that soil depth and the type of homogenous vegetation unit (HVU) had significant effects (p<0.01) on root biomass. The pair wise t-test showed that there were no significant difference in root biomass between sparsely encroached (HVU1) and grassland (HVU2) sites (p>0.05), but there were significant differences in root biomass between grassland (HVU2) and thicket (HVU3) site (p<0.05). The mean for total root biomass found in the study was 2.66 kg m-2. In all the trenches most of the root biomass was found in depth 1 (0-30 cm) which was 2.43 kg m-2followed by 1.32 kg m-2 in depth 2 (30-60 cm) and 0.49 kg m-2 in depth 3 (60-90 cm). According to the results on species composition, herbaceous biomass, basal cover, soil moisture content and the root biomass, Kwezana communal rangeland has a potential of running a sustainable livestock production enterprise if proper management practices can be implemented. To improve the rangelands of Kwezana communal rangelands, management such as proper resting, burning, proper stocking rates and physically clearing of bushes should be considered.
- Full Text: