Wild vegetables of the Eastern Cape of South Africa: the nutritional value and domestication of solanum nigrum l
- Authors: Bvenura, Callistus
- Date: 2014
- Language: English
- Type: Thesis , Doctoral , PhD (Ethnobotany)
- Identifier: vital:11885 , http://hdl.handle.net/10353/d1015514
- Description: An ethnobotanical survey was conducted in Alice and Willowvale in the Nkonkobe and Mbashe municipalities of the Eastern Cape Province, South Africa to identify and document wild vegetables growing in the areas. The survey documented 22 vegetable species belonging to 12 different families. The Amaryllidaceae, Amaranthaceae, Apiaceae, Asteraceae, Caryophyllaceae, Chenopodiaceae, Convolvulaceae, Cruciferae, Cucurbitaceaea, Euphorbiaceae, Tiliaceae, Solanaceae, Polygonaceae and Urticaceae were the families that were recorded. The species were Tulbaghia violacea Harv., Amaranthus blitoides S., Amaranthus blitum L., Amaranthus hybridus L., Centella coriacea Nannfd., Bidens pilosa L, Cotula heterocarpa DC., Sonchus oleraceus L., Galinsoga parviflora Cav., Taraxacum officinale Weber, Hypochaeris radicata L., Stellaria media L., Chenopodium album L., Chenopodium murale L., Ipomoea batatas L., Sisymbrium thellungii O. Schulz, Cucurbita pepo L., Rumex crispus L., Acalypha virginica L., Nicandra physalodes L., Physalis peruviana L., Solanum nigrum L., Urtica urens L. and Corchorus olitorius L. About 27 % of the wild vegetables were native to South Africa and about 45 % were also used as medicinal plants in the areas. Sun drying was the most common method of preserving the wild vegetables for the off season months. This study also revealed that, men and the younger generation knew less about wild vegetables than the women. The study also revealed a loss of knowledge of wild vegetables and their use by the rural dwellers who are more in favour of the exotic types such as spinach and cabbage.
- Full Text:
- Date Issued: 2014
Chemical transformations and phytochemical studies of bioactive components from extracts of Rosmarinus officinalis L
- Authors: Okoh, Omobola Oluranti
- Date: 2010
- Subjects: Essences and essential oils , Rosmarinus , Lamiaceae , Solution (Chemistry) , Extractive distillation , Medicinal plants , Bioactive compounds
- Language: English
- Type: Thesis , Doctoral , PhD (Chemistry)
- Identifier: vital:11331 , http://hdl.handle.net/10353/354 , Essences and essential oils , Rosmarinus , Lamiaceae , Solution (Chemistry) , Extractive distillation , Medicinal plants , Bioactive compounds
- Description: Variations in the yield, chemical composition, antibacterial, and antioxidant properties of the essential oils of Rosmarinus officinalis L. cultivated in Alice, Eastern Cape of South Africa over a period of 12 months using the solvent-free microwave extraction and traditional hydrodistillation methods were evaluated. The GC-MS analyses of the essential oils revealed the presence of 33 compounds with 1,8-cineole, a-pinene, camphor, verbenone, bornyl acetate and camphene constituting about 80 percent of the oils throughout the period of investigation, with the solvent-free microwave extraction method generally yielding more of the major components than the hydrodistillation method. Each of the major components of the oils varied in quantity and quality of yield at different periods of the year. The method of extraction and time of harvest are of importance to the quantity and quality of essential oil of Rosmarinus officinalis. Higher amounts of oxygenated monoterpenes such as borneol, camphor, terpene- 4-ol, linalool, a-terpeneol were present in the oil of SFME in comparison with HD. However, HD oil contained more monoterpene hydrocarbons such as a-pinene, camphene, β-pinene, myrcene, a-phellanderene, 1,8-cineole, trans- β-ocimene, γ-teprinene, and cis-sabinene hydrate than SFME extracted oil. Accumulation of monoterpene alcohols and ketones was observed during maturation process of Rosmarinus leaves. Quantitative evaluation of antibacterial activity, minimum inhibitory concentration values were determined using a serial microplate dilution method. The essential oils obtained using both methods of extraction were active against all the bacteria tested at a concentration of 10 mg mL-1. The minimum inhibitory concentrations for the SFME extracted oils ranged between 0.23 and 1.88 mg mL-1, while those of the HD extracted oils varied between 0.94 and 7.5 mg mL-1, thus suggesting that the oil obtained by solvent free microwave extraction was more active against bacteria than the oil obtained through hydrodistillation. The antioxidant and free radical scavenging activity of the obtained oils were tested by means of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH+) assay and β- carotene bleaching test. In the DPPH+ assay, while the free radical scavenging activity of the oil obtained by SFME method showed percentage inhibitions of between 48.8 percent and 67 percent, the HD derived oil showed inhibitions of between 52.2 percent and 65.30 percent at concentrations of 0.33, 0.50 and 1.0 mg mL-1, respectively. In the β-carotene bleaching assay, the percentage inhibition increased with increasing concentration of both oils with a higher antioxidant activity of the oil obtained through the SFME than the HD method. Thin layer chromatography (TLC) was used to analyze the chemical composition of the extracts using three eluent solvent systems of varying polarities i. e. CEF, BEA and EMW and sprayed with vanillin-sulfuric acid. The chemical composition of the different extracts was similar with the exception of methanol and water extracts which had only one or two visible compounds after treating with vanillin-spray reagent. To evaluate the number of antibacterial compounds present in the fractions, bioautography was used against two most important nosocomial microorganisms. S. aureus (Gram positive) and E. coli (Gram negative). Nearly all the crude serial extraction fractions contained compounds that inhibited the growth of E. coli. The hexane extract had the most lines of inhibition followed by ethyl acetate. Bioassay-guided fractionation against E. coli was used to isolate antibacterial compounds. The largest number of antibacterial compounds occurred in the hexane fraction. Furthermore we tried to complete the characterization by extracting and studying other biologically important plant metabolites such as phenolic compounds to evaluate the antioxidant capacity of Rosmarinus extracts.
- Full Text:
- Date Issued: 2010
Dynamic adaptive cost model for wireless Internet connectivity in African rural communities
- Authors: Sibanda, Khulumani
- Date: 2010
- Subjects: Internet , Community development -- South Africa -- Eastern Cape , Cost effectiveness , Wireless communication systems , Rural development -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Computer Science)
- Identifier: vital:11389 , http://hdl.handle.net/10353/380 , Internet , Community development -- South Africa -- Eastern Cape , Cost effectiveness , Wireless communication systems , Rural development -- South Africa -- Eastern Cape
- Description: In today’s dynamic technological landscape, wireless communication networks have become an important part of economic development. The emergence of wireless technologies raises hopes to extend communication to remote areas that have not seen any tangible deployment to date. As developing nations pin their hopes to wireless technologies, cost models for wireless communication networks are becoming vital to support the emerging technologies. However, varying cost changes raise critical challenges to the estimation of both capital expenditure and operational expenditure. The network deployment process has numerous events that may cause adjustments to initially estimated project costs. These adjustments are necessary for a cost management plan and this plan includes monitoring cost performance and ensuring that only appropriate changes are made to the network project. The incidents that may cause cost changes can not be entirely predicted as their distribution tend to change dynamically from time to time. Estimating network deployment costs in such a dynamic environment necessitates cost models that can adapt to random occurrence of cost changes. Widely used cost models are usually performed by experienced personnel whose engineering experience is derived from deploying similar networks. In this approach experienced personnel add a certain percentage to the cost estimate to cater for contingency costs. Certainly such an approach depends on individual opinion, making it subjective and void of mathematical estimating relationships which are of paramount importance in ensuring that estimated deployment costs are sufficient to deal with cost uncertainties. We observe that existing approaches can only explore a limited solution space and hence can lead to cost overruns if implemented in dynamically cost changing environments. This thesis presents a wireless communication network deployment cost model that incorporates uncertainties into the final cost estimate. The model is adaptive to unpredictable cost changes since it allows adjustments of confidence levels when calculating contingency costs. This allows dynamically updating the cost changes without the cost model being reconstructed from scratch. We make use of the Poisson process in modeling the occurrence of incidents that are responsible for causing cost changes during network deployment. We also show that the occurrence of the incidents causing cost change are random and tend to follow the Poisson distribution. Using different levels of confidence we model various cost contingencies and make sensitivity analyses to identify the probability of cost overrun when given different contingencies. The dynamic adaptive cost model can be used either at the strategic level to understand the cost of a particular technique or at the operational level, as a way to show how Poisson process in network deployment can compare with engineering experience and other estimating techniques. We believe that the model is useful for remote areas where deployment costs are volatile and the distribution of incidents causing cost change to original cost estimates are diverse and dynamically changing. Further we expect that our research improves the knowledge base of information about the costs for rural communities to connect to the Internet, consequently providing useful input to future policy debates. This work is further poised to be a utility function to help those planning internet infrastructure deployments in least developed regions.
- Full Text:
- Date Issued: 2010
Aggregate stability, crust formation, steady state infiltration and mode of seedling emergence in soils with various texture and mineralogy
- Authors: Nciizah, Adornis Dakarai
- Date: 2014
- Language: English
- Type: Thesis , Doctoral , PhD (Crop Science)
- Identifier: vital:11871 , http://hdl.handle.net/10353/d1015539
- Description: The general objective of this study was to quantify the interactive effects of soil texture and mineralogy on soil crusting, infiltration and erosion and the subsequent effects on maize seedling emergence and early development using soils collected from 14 ecotopes in the Eastern Cape Province. The specific objectives were to determine; i) particulate organic matter, soil texture and mineralogy relations, ii) aggregate stability and breakdown mechanisms as affected by soil texture and organic matter, iii) crust formation and steady state infiltration, iv) rainfall pattern effects on crusting, infiltration and erodibility and v) rainfall intensity effects on crusting and mode of seedling emergence. Particulate organic matter (POM) was fractionated into litter POM, coarse POM and fine POM. Both total soil organic matter (SOM) and the POM in each fraction were determined using the weight loss on ignition procedure. Most ecotopes were either sandy loam or sandy clay loam and primary minerals especially quartz dominated the soil mineralogy. The clay content was significantly related to the total SOM (r = 0.78), hematite (r = 0.83) and quartz (r = -0.74). Aggregate stability was determined following methods described by Le Bissonnais (1996) i.e. fast wetting (FW), slow wetting (SW) and wet stirring (WSt). Aggregate breakdown followed the order; slaking < mechanical breakdown < micro-cracking for most ecotopes except Lujiko Leeufontein and Amatola Jozini where SW and WSt resulted in the least MWD respectively. Aggregate stability was significantly correlated to POM only for FW and SW and only positive but not significant for WSt. To study crust formation, aggregate sizes <2, 2 to 3, 3 to 5 mm were exposed to 60 mm hr-1 simulated rainfall. Sieving structural crusts, ~0.2 to ~0.8 mm thick with a surface layer of loose grains overlying a thin plasmic layer, formed in all ecotopes. Crusts with strengths between 0.25 and 3.42 10-4 kg m-2 developed on the <2 mm compared to <2.23 10-4 kg m-2 in the >2 mm aggregates. The reverse occurred in Alice Jozini, which had relatively low clay content of 120 g kg-1. Two significantly different groups of the SSIR were observed. The SSIR was between 1.24 and 3.60 mm hr-1 in the group of ecotopes dominated by primary minerals and relatively lower clay content. In the second group, consisting one ecotope dominated by kaolinite and relatively higher clay content, the SSIR was 15.23 mm hr-1. Rainfall pattern i.e. rainfall applied either as an eight minute single rainstorm (SR) or four-two minute intermittent rainstorms (IR) separated by a 48 h drying period significantly (p < 0.05) affected crust strength, SSIR and erosion. The IR resulted in higher crust strength and SSIR than SR. The effect of rainfall pattern on SSIR was mostly influenced by the primary minerals namely, quartz. Three maize seeds of equal size were planted in plastic pots, pre-wetted by capillary action and then subjected to simulated rainfall at three intensities for 5 min. Rainfall intensity (30, 45 and 60 mm h-1) significantly (P < 0.05) affected crust strength and mean emergence day (MED) but not emergence percentage (EMP) and shoot length (P > 0.05). The 60 mm h-1 rainfall intensity resulted in the highest crust strength and MED.
- Full Text:
- Date Issued: 2014
On the evaluation of spectral effects on photovoltaic modules performance parameters and hotspots in solar cells
- Authors: Simon, Michael
- Date: 2009
- Subjects: Photovoltaic cells , Energy dissipation , Electric power production , Photovoltaic power generation , Solar energy , Spectral energy distribution
- Language: English
- Type: Thesis , Doctoral , PhD (Physics)
- Identifier: vital:11593 , http://hdl.handle.net/10353/257 , Photovoltaic cells , Energy dissipation , Electric power production , Photovoltaic power generation , Solar energy , Spectral energy distribution
- Description: The performance of photovoltaic (PV) modules in terms of their ability to convert incident photon to electrical energy (efficiency) depends mostly on the spectral distribution of incident radiation from the sun. The incident spectrum finally perceived by the module depends strongly on the composition of the medium in which it has traveled. The composition of the earth’s atmosphere, which includes, amongst others, water vapour, gases such as carbon dioxide and oxygen, absorbs or scatters some of the sunlight. The incident solar spectrum is also modified by the diffuse aspect of radiation from the sky which strongly depends on aerosol concentration, cloudiness and local reflection of the earth’s surface. Although it is well known that the changes in outdoor spectrum affect device performance, little work has been conducted to support this theory. This is probably due to lack of spectral data or in certain instances where data is available, little knowledge of interpreting that data. The outdoor spectral data that one obtains in the field does not come clearly for just simple interpretation. Different analytical interpretation procedures have been proposed, all trying to explain and quantify the spectral influence on PV devices. In this study an assessment methodology for evaluating the effects of outdoor spectra on device performance parameters during the course of the day, seasons and or cloudy cover has been developed. The methodology consists of developing a device dependant concept, Weighted Useful Fraction (WUF) using the outdoor measured spectral data. For measuring PV module’s performance parameters, a current-voltage (I-V) tester was developed in order to monitor the performance of six different module technologies. The Gaussian distribution was used to interpret the data. For hot-spot analysis, different techniques were used, which include Infrared thermographic technique for identifying the hot-spots in the solar cells, SEM and EDX techniques. The AES technique was also used in order to identify other elements at hot-spots sites that could not be detected by the EDX technique. iii Results obtained indicate that multicrystalline modules performance is affected by the changes in the outdoor spectrum during summer or winter seasons. The modules prefer a spectrum characterized by WUF = 0.809 during summer season. This spectrum corresponds to AM 2.19 which is different from AM 1.5 used for device ratings. In winter, the mc-Si module’s WUF (0.7125) peaks at 13h00 at a value corresponding to AM 1.83. Although these devices have a wider wavelength range, they respond differently in real outdoor environment. Results for mono – Si module showed that the device performs best at WUF = 0.6457 which corresponds to AM 1.83 during summer season, while it operates optimally under a winter spectrum indicated by WUF of 0.5691 (AM2.58). The seasonal changes resulted in the shift in WUF during day time corresponding to the “preferred” spectrum. This shift indicates that these devices should be rated using AM values that correspond to the WUF values under which the device operates optimally. For poly-Si, it was also observed the WUF values are lower than the other two crystalline-Si counterparts. The pc-Si was observed to prefer a lower AM value indicated by WUF = 0.5813 during winter season while for summer it prefers a spectrum characterized by WUF = 0.5541 at AM 3.36. The performance of the single junction a-Si module degraded by 67 percent after an initial outdoor exposure of 16 kWh/m² while the HIT module did not exhibit the initial degradation regardless of their similarities in material composition. It was established that the WUF before degradation peaks at 15h00 at a value of 0.7130 corresponding to AM 4.50 while the WUF after degradation “prefers” the spectrum (WUF = 0.6578) experienced at 15h30 corresponding to AM value of 5.57. Comparing the before and after degradation scenarios of a-Si:H, it was observed that the device spends less time under the red spectrum which implies that the device “prefers” a full spectrum to operate optimally. The degradation of a-Si:H device revealed that the device spectral response was also shifted by a 7.7 percent after degradation. A higher percentage difference (61.8 percent) for spectral range for the HIT module is observed, but with no effects on device parameters. Seasonal changes (summer/winter) resulted in the outdoor spectrum of CuInSe2 to vary by WUF = 1.5 percent, which resulted in the decrease in Isc. This was ascertained by iv analyzing the percentage change in WUF and evaluating the corresponding change in Isc. The analysis showed that there was a large percentage difference of the module’s Isc as the outdoor spectrum changed during the course of the day. This confirmed that the 17 percent decrease in Isc was due to a WUF of 1.5 percent. In mc-Si solar cells used in this study, it was found that elemental composition across the entire solar cell was not homogenously distributed resulting in high concentration of transition metals which were detected at hot spot areas. The presence of transition metals causes hot-spot formation in crystalline solar cells. Although several transition elements exist at hot-spot regions, the presence of oxygen, carbon, iron and platinum was detected in high concentrations. From this study, it is highly recommended that transition elements and oxygen must be minimized so as to increase the life expectancy of these devices and improve overall systems reliability
- Full Text:
- Date Issued: 2009
Communal production systems of goats raised by resource-poor farmers in the Eastern Cape Province of South Africa
- Authors: Gwaze, Francisca Rumosa
- Date: 2008
- Subjects: Agriculture -- Economic aspects -- South Africa -- Eastern Cape , Commons -- South Africa -- Eastern Cape , Pastoral systems -- Economic aspects -- South Africa -- Eastern Cape , Goats -- Economic aspects -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Animal Science)
- Identifier: vital:11578 , http://hdl.handle.net/10353/172 , Agriculture -- Economic aspects -- South Africa -- Eastern Cape , Commons -- South Africa -- Eastern Cape , Pastoral systems -- Economic aspects -- South Africa -- Eastern Cape , Goats -- Economic aspects -- South Africa -- Eastern Cape
- Description: Goats significantly contribute towards the subsistence, economic and social livelihoods of many resource-poor farmers in developing countries, the majority of which own goats. There, however, is dearth of information on communal goat production potential and roles to the rural populace. The broad objective of the study was to evaluate production practices, constraints, production efficiency and to determine nutritional and health status of goats raised by resource-poor communal farmers in the Eastern Cape Province of South Africa. Roles and management systems of goats, goat flock dynamics and, prevalence and loads of gastrointestinal infections and the nutritional status of goats in the study areas were determined. The relationships among body weight, body condition score, faecal egg counts and, haematological and biochemical profiles were also determined. Mean goat flock sizes per household were similar between the two districts studied; Amatole (14.0 ± 0.31) and Alfred Nzo (14.1 ± 1.42). Seventy-nine percent of households in Amatole and 78% in Alfred Nzo kept goats for ceremonies, such as the initiation ceremonies. Goat houses in the two districts were poorly constructed. Thirty two percent of farmers in Alfred Nzo district and 27% in Amatole district reported low buck to doe ratios, suggesting that inbreeding might have been reducing productivity of their flocks. Kid mortality had two major peaks; in May (21%) and in September (21%). Goat production potential (GPP), the proportion of mature and growing goats to the total flock size, was affected by gender of owner of goats. Goats owned by female had a significantly lower GPP value of 0.63 ± 0.015 than goats owned by male farmers (0.70 ± 0.010). Month also significantly affected GPP with the highest (P < 0.05) GPP recorded in May, June and July and the lowest in March and April. Village affected GPP with values for Nkosana and Qawukeni being significantly higher than for Mankone. Goat production potential was also higher (P < 0.05) in small flocks (0.04 ± 0.008) than in large flocks (0.02 ± 0.008). Goat production efficiency (GPE) ranged from 0.11 ± 0.193 in April to 1.55 ± 0.193 in December. The most prevalent gastrointestinal eggs were the strongyle egg type (68.4 ± 8.49 in Qawukeni and 96.1 ± 12.01 in Nkosana) followed by coccidia (53.3 ± 8.76 in Qawukeni and 68.8 ± 8.00 in Mankone). The other identified nematodes were Strongyloides and Trichostrongylus egg types. The trematodes observed were Fasciola and Paramphistomum species. High loads of strongyle eggs were observed in the hot-wet season and the post-rainy season, whilst the other egg types showed a peak in the hot-wet season only. For most of the gastrointestinal parasite eggs, prevalence was higher (P < 0.05) in the sour rangeland compared to the sweet rangeland. Higher (P < 0.05) levels of total protein (TP), globulin, aspartate aminotransferase (AST) and creatinine kinase (CK) levels were recorded in the wet than in the dry season. Body condition scores were positively correlated (P < 0.05) to albumin, body weight and packed cell volume. However, body condition scores were negatively correlated to TP, glucose, alanine transaminase (ALT) and AST. Strongyle egg loads were positively correlated to FAMACHA scores, packed cell volume, body weight and body condition score. The observed high globulin levels suggested a chronic health challenge. Thus, it is fundamental to devise affordable interventions for the control of gastrointestinal parasites in communal goats leading to improved goat productivity and hence rural livelihood
- Full Text:
- Date Issued: 2008
Antifugal evaluation and phytochemical analysis of selected medicinal plants used in the treatment of fungal diseases associated with HIV infection in the Eastern Cape Province, South Africa
- Authors: Mbeng, Wilfred Otang
- Date: 2013
- Subjects: Medicinal plants -- ethnobotanical survey , Opportunistic fungal infections , HIV/AIDS -- Cytotoxicity , Eastern Cape -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD (Botany)
- Identifier: vital:11307 , http://hdl.handle.net/10353/d1006834 , Medicinal plants -- ethnobotanical survey , Opportunistic fungal infections , HIV/AIDS -- Cytotoxicity , Eastern Cape -- South Africa
- Description: Background. As a result of the AIDS pandemic, many people areimmuno compromised andopportunistic fungal infections (OFIs) such as candidiasis are common. Despite the widespread use of medicinal plants in South Africa, there is a dearth of knowledge regarding the use of such plants in the management of these infections. This study evaluates three South African medicinal plants (Arctotis arctotoides, Pittosporum viridiflorum, and Gasteria bicolor) traditionally used in the treatment of OFIs in HIV/AIDS patients, in the Eastern Cape Province, South Africa. Materials and methods. A six-stage process of documentation, evaluation and analysis of results was conducted: (1) Selection of medicinal plants most frequently used in the treatment of OFIs through ethnomedical studies and the survey of specialised literature; (2) Collection and preparation of the extract of each plant; (3) Antifungal evaluation of the crude plant extracts. (4) Phytochemical and antioxidant evaluation of the active crude plant extracts; (5) Cytotoxicity evaluation of the bioactive extracts using the Chang liver cell line, and (6) Statistical analysis of the results. Ethnobotanical information was obtained through interviews with traditional healers and AIDS patients with the aid of semi-structured questionnaires, direct observations and by reviewing studies reported in the literature. Following the approval from the University of Fort Hare‘s Ethics Committee, 101 HIV/AIDS patients were recruited through convenience sampling into an anonymous cross-sectional questionnaire study. The agar diffusion and micro-dilution methods were used to determine the antifungal activities of the hexane, acetone and aqueous extracts of A. arctotoides, G. bicolor and P. viridiflorum against 10 opportunistic fungi.
- Full Text:
- Date Issued: 2013
Biochemical evaluation of Tulbaghia violacea harv.rhizomes in diet induced hypercholestrolemic rats
- Authors: Olorunnisola, Olubukola Sinbad
- Date: 2012
- Subjects: Violaceae , Anticoagulants (Medicine) , Antineoplastic agents , Rats , Hypercholesteremia , Cardiovascular agents , Medicinal plants
- Language: English
- Type: Thesis , Doctoral , PhD (Biochemistry)
- Identifier: vital:11273 , http://hdl.handle.net/10353/d1006900 , Violaceae , Anticoagulants (Medicine) , Antineoplastic agents , Rats , Hypercholesteremia , Cardiovascular agents , Medicinal plants
- Description: Discovery of cheap, nontoxic and readily available antiatherosclerotic drugs is an extraordinary challenge in this modern world. Atherosclerosis and cardiovascular diseases have been predicted to be the leading cause of death by the year 2030. Hence, this thesis was designed to search for plant (s) with anti-atherogenic properties, investigate its possible side effects and extrapolate its likely mechanism(s) of action. An ethnobotanical survey was employed in identification of locally important plants used for the management and treatment of cardiovascular diseases and its predisposing factors in Nkonkobe Municipality, Eastern Cape in South Africa. Information on the names of plants, their parts used and methods of preparation was collected through a questionnaire which was administered to herbalists, traditional healers and rural dwellers. The most frequently used plant (Rhizomes of Tulbaghia violacea Harv.) was investigated for toxicity using brine shrimp lethality (in vitro) and in vivo toxicity test (acute and subchronic) on rats to determine safety dosage. The in vitro antioxidant and free radical scavenging activity of the plant was investigated using models such as 1,1-diphenyl-2- picrylhydrazyl (DPPH), superoxide anions, hydrogen peroxide (H2O2), nitric oxide (NO), 2,2’- azinobis [3-ethylbenzothiazoline-6-sulfonic acid] diammonium salt (ABTS), lipid peroxidation inhibition and the ferric reducing agent. Phytochemical content and the effect of oral administration of fresh methanolic extract rhizomes of Tulbaghia violacea (250, 500 mg/kg. bwt/day) on Lipid peroxidation (TBARS), serum and tissue antioxidant enzymes in normal, hypercholesterolemic and diet induced atherogenic rats were also assessed. More so, the potential of the extract (250 and 500 mg/kg. bwt) to protect against atherogenic diet (4 percentage cholesterol 1 pecentage cholic acid and 0.5 percentage thiouracil) induced fatty streaks formation, dyslipidemia, oxidative stress and endothelial dysfunction was also investigated. Ethnobotanical study revealed that 19 plant species are used for the treatment of heart related diseases in the Municipality. 53 percentage of the plants mentioned were used for the management of chest pain, 47 percentage for high blood pressure, 42 percent for heart disease, 16 percentage for stroke and 11 percentage for the treatment of hypercholesterolemia. Tulbaghia violacea was repeatedly mentioned as the plant species used for the treatment of high blood pressure and predisposing factors in the study area. The brine shrimp cytotoxicity test revealed that fresh, dried methanolic extracts and essential oil of the T. violacea exhibited a high degree of cytotoxic activity with IC50 values of 18.18 (fresh) and 19.24 (dried) μg/ml. An IC50 value of 12. 59 μg/ml was obtained for the essential oil of the plant. The low cytotoxicity values obtained, suggested that rhizome of T. violacea may serve as a potential source of antimicrobial and anticancer agents. In vivo acute study of single oral administration of 5g/kg dose does not produce mortality or significant behavioral changes during 14 days observation. In the sub-chronic study, the extract (250, 500 mg/kg/bwt/ day) administered for a period of 28 days showed no mortality or morbidity. The weekly body and organ weight of the rats showed no significant differences between the control and the rats treated with the extract. The extract at all doses does not show any effect on of biomarkers of liver or renal damage. However, a significant decrease in the activity of ƔGT was observed in the extract treated groups. Hematological evaluation revealed that oral administration of fresh methanolic extracts of rhizomes of T. violacea does not cause anaemia or leucocytosis in the animals. Furthermore, histopathology results of the internal organs revealed no detectable inflammation. These results demonstrated that the rhizome extract of T. violacea was potentially safe for consumption orally even in chronic concentration. In vitro antioxidant evaluation showed that the essential oil, fresh and dried methanolic extracts exhibited potent antioxidant activities in a concentration dependent manner. Phytochemical investigation reveals that the fresh and the dry extract of RTV are rich in flavonoid, flavonol, phenols, tannin and proanthocyanidin, while the essential oil contained dimethy disulfide, dimethyl trisulfide, (methyl methylthio) methyl, 2,4-dithiapentane (11.35 percent) and (methylthio) acetic acid, 2- (methylthio) ethanol, 3-(methylthio) - and propanenitrile (7.20 percent). The fresh extract had higher radicals scavenging activity than the essential oil or dried extract, with 50 percentage inhibition of DPPH, hydrogen peroxide and lipid peroxidation at a concentration of 35.0 ± 0.12, 19.3 ± 0.11 and 17.9 ± 0.15 μg/ml respectively. Oral administration of methanolic extract of RTV in 125, 250 and 500 mg/kg to female Wistar rats significantly inhibited reduction of glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT). The extracts also inhibited (p< 0.05) lipid peroxidation in normal, high cholesterol and diet induced atherosclerosis fed rats in a dose dependant manner. Also the extract (250 and 500 mg/kg/bwt/day) caused a significant (p<0.05) improvement in body weight of treated animals compared with untreated hypercholesterolemia control rats. The extracts also protected significantly (p<0.05) against atherogenic diet induced liver damage or fatty streaks formation in the aorta as revealed by histological examination. The anti-cholesterolemia and anti-atherosclerotic activities of the extract compared favorably well with standard drugs Gemfibrozil and Atorvastatin respectively. Conclusively, rhizomes of T. violacea possess significant anti-atherogenic activity and its mechanism of action(s) may be due to its antioxidant and anti-hypercholesterolemia properties. The results of this study also suggested that rhizome of T. violacea is relatively safe for human consumption and it may be used as an alternative to garlic.
- Full Text:
- Date Issued: 2012
Evaluation of flocculating potentials and charecterization of bioflocculants produced by three bacterial isolates from Algoa Bay, South Africa
- Authors: Okaiyeto, Kunle
- Date: 2016
- Subjects: Flocculation Water -- Purification -- Flocculation Water quality management
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/2633 , vital:27947
- Description: Flocculation has been widely adopted as one of the most effective methods to remove colloidal particles in water or wastewater treatment. Synthetic flocculants are conventionally used because of their high flocculating efficiency and cost-effectiveness. However, they have been reported to have hazardous properties and implicated in some serious health problems including senile dementia and neuro-toxicity, as well as being recalcitrant in the environment. Consequently, efforts are being geared away from the use of synthetic flocculants in water and wastewater treatment. Hence, the need for safe and eco-friendly flocculants has become imperative. Compared with synthetic flocculants, bioflocculants have special advantages such as safety, biodegradability and harmlessness to the environment and humans; attributes which make them potential alternatives in water treatment, downstream as well as fermentation processes. In the current study, the potentials of bacterial isolates recovered from Algoa Bay in the Eastern Cape Province of South Africa for bioflocculant production were investigated. The bacterial isolates were identified by polymerase chain reaction (PCR) as belonging to the Bacillus genus. The analysis of 16S ribosomal deoxyribonucleic acid (rDNA) nucleotide sequence of isolate M72 showed 99 percent similarity to Bacillus toyonensis strain BCT-7112 and was deposited in the GenBank as Bacillus toyonensis strain AEMREG6 with accession number KP406731. Likewise, the 16S rDNA nucleotide sequences of isolates M69 and M67 showed 98 percent sequence similarity to Bacillus licheniformis strain W7 and Bacillus algicola strain QD43 respectively; and M67 isolate was subsequently deposited in the GenBank as Bacillus sp. AEMREG7 with accession number KF933697.1. The results of the nutritional requirements and fermentation conditions revealed that optimum inoculum size for REG-6 production was 4 percent (v/v), while 5 percent (v/v) and 3 percent (v/v) were most favourable for MBF-W7 and MBF-UFH production respectively. Glucose was the best carbon source for the production of bioflocculants (REG-6 and MBF-UFH) by Bacillus toyonensis AEMREG6 and Bacillus sp. AEMREG7 respectively, while maltose supported optimum bioflocculant (MBF-W7) production by Bacillus specie. Inorganic nitrogen (NH4NO3) was the favoured nitrogen source for both REG-6 and MBF-W7 production, while mixed nitrogen sources [yeast extract + urea + (NH4)2SO4] supported the maximum production of MBF-UFH. The initial medium pH for REG-6 was 5, while MBF-W7 and MBF-UFH were both maximally produced at the initial pH of 6. After a 96 h cultivation period under optimal culture conditions, 3.2 g of purified REG-6 with a maximum flocculating activity of 77 percent was recovered from 1 L fermented broth of Bacillus toyonensis AEMREG6. Yields of 3.8 g and 1.6 g pure bioflocculants with the respective highest flocculating activities of 94.9 percent and 83.2 percent were also obtained from 1 L, 72 h-fermented broths of Bacillus licheniformis and Bacillus sp. AEMREG7 respectively. Furthermore, all the three bioflocculants (REG-6, MBF-W7 and MBF-UFH), displayed thermal stability within the temperature range of 50 to 100 oC, with strong flocculating activities of over 80 percent against kaolin suspension over a wide range of pH range (3–11) and relatively low dosage requirements of 0.1-03 mg/ml in the presence of divalent cations in the treatment of kaolin clay suspension and Thyme River waters. Chemical composition analyses of the bioflocculants showed them to be glycoproteins with a predominantly polysaccharide backbones as shown by the following carbohydrate/protein (w/w) ratios: 77.8 percent:11.5 percent (REG-6); 73.7 percent:6.2 percent (MBF-W7) and 76 percent:14 percent (MBF-UFH).
- Full Text:
- Date Issued: 2016
Synthesis, characterization & application of visible light responsive nitrogen doped Tio2 and copolymer-grafted asymmetric membranes with ozonolysis for water treatment
- Authors: Mungondori, Henry H
- Date: 2015
- Language: English
- Type: Thesis , Doctoral , PhD (Chemistry)
- Identifier: vital:11350 , http://hdl.handle.net/10353/d1020257
- Description: The use of titanium dioxide for the photo-catalytic removal of organic, inorganic, and microbial pollutants from natural water and wastewater has been considered a very promising technique. The aim of this study was to prepare nitrogen doped titanium dioxide, immobilize it on asymmetric polymeric membranes of poly (methacrylic acid) grafted onto poly (vinylidene difluoride) (PVDF) blended with poly (acrylonitrile) (PAN), and evaluate the photo-catalytic, antimicrobial, and antifouling properties of the membranes. Nitrogen doped titanium dioxide (N-TiO2) nano-particles were prepared by a low temperature sol gel synthesis technique. The modification of TiO2 with nitrogen allows photo-sensitization of the photo-catalyst towards visible light utilization. The N-TiO2 nano-particles were characterized by fourier transform infrared spectroscopy (FT-IR), scanning x-ray photoelectron spectroscopy (SXPS), X-ray diffraction analysis (XRD), diffuse reflectance spectroscopy (DRS), Brunauer Emmett Teller (BET) surface area analysis, and transmission electron microscopy (TEM). The characterizations revealed the presence of the expected functional groups and confirmed successful doping and that the product was visible light responsive. Novel poly (methacrylic acid) grafted onto poly (vinylidene difluoride)/ poly (acrylonitrile) (PMAA-g-PVDF/ PAN) asymmetric membranes were prepared by the dry-wet phase inversion technique. The poly (methacrylic acid) (PMAA) side chains where grafted onto an activated PVDF backbone by reversible addition fragmentation chain transfer (RAFT) polymerization. The photo-catalytic membranes were generated by blending N-TiO2 with the polymer solution before casting the membranes. The membranes were characterized by FT-IR, nuclear magnetic resonance spectroscopy (NMR), scanning electron microscopy (SEM), and thermo-gravimetric analysis (TGA). FT-IR and NMR analyses confirmed successful grafting of MAA chains onto PVDF while SEM confirmed the successful preparation of membranes with asymmetric structure. The efficacy of the photo-catalytic asymmetric membranes was evaluated on the removal of herbicides from synthetic water. Bentazon was easily degraded while atrazine and paraquat were recalcitrant and proved difficult to degrade. The best results were observed with 3 % N-TiO2-PMAA-g-PVDF/ PAN asymmetric membranes on the photo-degradation of bentazon, atrazine and paraquat in water. Significant enhancement in the photo-degradation of the three herbicides was observed when photo-catalytic degradation was coupled with ozonation. Liquid chromatography-mass spectrometry (LC-MS) analysis confirmed the presence of a degradation by-product during the photo-catalytic degradation of bentazon. The photo-catalytic membranes were also evaluated on the photo-catalytic reduction of heavy metals Pb2+ and Fe3+ in water, and the best results were obtained using 1 % N-TiO2-PMAA-g-PVDF/ PAN and 1 % N-TiO2-PAN asymmetric membranes. All prepared photo-catalytic membranes where capable of completely inactivating E. coli ATCC 8739 within 120 minutes of exposure and inactivation rate increased with increasing N-TiO2 photo-catalyst loading. However, there was an indication from the results obtained that N-TiO2 supported on PMAA-g-PVDF/ PAN showed a higher inactivation rate of E. coli ATCC 8739 compared to N-TiO2-PAN and N-TiO2-PVDF membranes. The 1 % N-TiO2-PMAA-g-PVDF/ PAN membranes gave the highest pure water flux (421.83 L/m2h). This increase (PVDF = 30.50 L/m2h, PAN = 73.85 L/m2h) in pure water flux is owedb to PMAA grafting as well as addition of N-TiO2. These modifications resulted in an increased membrane surface hydrophilicity, which promoted permeation of pure water through the membrane structure. A high bovine serum albumin (BSA) rejection (76.5 %) was noted and can be attributed to steric hindrance brought about by PMAA side chains which prevented the bulky BSA molecules from attaching to the membrane surface for PMAA-g-PVDF/ PAN membranes. However, the supporting porous sub-layer of an asymmetric membrane seemed to play a very important role in the overall permeability of a membrane. PVDF membranes are highly hydrophobic hence they gave a very low pure water flux.
- Full Text:
- Date Issued: 2015
Studies on the nutritional value of seven accessions of cocoyam growing in South Africa
- Authors: Lewu, Muinat Nike
- Date: 2010
- Subjects: Taro , Nutrition , Field crops -- Nutrition , Taro -- Nutritional aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:11305 , http://hdl.handle.net/10353/d1001054 , Taro , Nutrition , Field crops -- Nutrition , Taro -- Nutritional aspects
- Description: Cocoyam [Colocasia esculenta (L.) Schott] is widely cultivated as a staple food in the tropical and subtropical regions of the world. The crop, however, remains unpopular and not well known outside KwaZulu-Natal Province of South Africa where it is cultivated mainly for subsistence. The aims of the study were to collect local landraces (accessions) of the crop from where it is found growing within the country for various studies and also to document its nutritional values as well as the safety/toxicity of the crop. The study was carried out using various methods. These included a comparative assessment of the proximate, mineral and antinutrient compositions of cooked and uncooked tubers of a typical commercially available cocoyam and potato found in South African markets. These investigations were repeated for the tubers and leaves of available landraces (seven accessions) of C. esculenta found growing in the farmers’ fields in KwaZulu-Natal Province. Also, an in vivo toxicological study on cooked accessions of the local landraces was conducted to determine possible toxicity effects after consumption using albino rats as a model. The results revealed that commercially available cocoyam and potato tubers have very close nutritional components. Analysis of the proximate composition of seven accessions (UFCe1- UFCe7) of cooked and uncooked tubers of cocoyam indicated that UFCe7 was better in ash, crude protein, crude fibre and crude lipid contents but with higher moisture which could make it more vulnerable to microbial attack. No tubers of the seven accessions appeared to be ii outstandingly better than the others based on their mineral compositions. However, in terms of antinutritional factors, UFCe1, UFCe3 and UFCe7 had the least amounts of oxalate, tannins and phytate in their cooked states. It was discovered however, that the leaves of the accessions of this vegetable contain substantial amount of minerals, and therefore, can contribute significantly to the nutrient requirements of humans and could be recommended as a cheap source of nutrients in South Africa. None of the accessions was outstandingly better than the others in terms of their mineral contents and anti-nutritional factors. Moreover, the current study has shown that boiling the leaves of cocoyam prior to consumption is an effective way of reducing the antinutrient contents of the leaves of the plant thereby making it safe for consumption. The findings also revealed that cooking C. esculenta leaves may increase the levels of protein, fibre and lipid contents while cooking may also decrease the mineral, carbohydrate and caloric contents of the leaves of the accessions. The leafy vegetable may, therefore, be recommended as a cheap source of plant protein. Cooking improved the nutritive value as a result of the reduction in antinutrient levels, thereby improving the food quality in all the tuber and leaf samples used for this study. At the same time, cooked samples also suffered loss of some nutrients with respect to the proximate and mineral compositions. However, supplementation from other food sources that are rich in these nutrients is necessary when these crops are cooked for consumption. Any of the cocoyam accessions may be recommended for consumption for improved protein and mineral nutrients while tubers of accession UFCe7 have also shown good promise in terms of protein and fibre content availability. The results of the in vivo study, using the liver and kidney functional endpoints of weanling albino rats (Rattus norvegicus) maintained on different accessions of cooked cocoyam-based iii diets (UFCe1-UFCe7) for 28 days, revealed that all the accessions produced selective alterations on the hepatorenal indices of weanling rats. The highest alterations were produced by UFCe4 while the least was from UFCe2. These alterations may have consequential effects on the normal functioning of the liver and kidney of the animals. The UFCe2 exhibited the least toxicity risk among the accessions of C. esculenta growing in KwaZulu-Natal Province of South Africa.
- Full Text:
- Date Issued: 2010
Synthesis, characterization, and biological studies of pyrazolone Schiff bases and their transition metal complexes
- Authors: Idemudia, Omoruyi Gold
- Date: 2014
- Language: English
- Type: Thesis , Doctoral , PhD (Chemistry)
- Identifier: vital:11340 , http://hdl.handle.net/10353/d1016068
- Description: Some new acylpyrazolone Schiff bases have been synthesized from the condensation reaction of two acylpyrazolone diketone precursors with phenylhydrazine, 2,4-dinitrophenylhydrazine and sulfanilamide. They have been fully characterized by elemental analysis and spectroscopic techniques (IR,1H and 13C NMR, and mass-spectra). The single crystal structure of the benzoyl derivative acylpyrazolone Schiff bases have been obtained and analyzed by X-ray crystallography technique. Solid state X-ray diffraction revealed a keto tautomer Schiff base in solid state. Mn(II), Co(II), Ni(II) and Cu(II) complexes with the Schiff bases have been synthesized and characterized by elemental analysis, IR and UV-VIS spectroscopy, magnetic susceptibility measurements, and thermal studies (TGA and DTG). An octahedral geometry around the transition metal ion, consisting of two bidentate Schiff base ligands bonding through the azometine nitrogen and ketonic oxygen have been proposed based on careful interpretation of available analytical and spectroscopic characterization results. Two water molecules as ligands complete the octahedral geometry in all cases. Using the invitro disc diffusion method for screening synthesized compounds against selected gram positive and gram negative bacterial at 40 mg/mL, and the DPPH free radical scavenging methods at 0.50, 0.25 and 0.13 mg/mL, the synthesized Schiff base and metal complexes showed varying biological activities. 4-benzoyl-3-methyl-1-phenyl-2-pyrazolin-5-one sul29 fanilamide showed more activity generally, exhibiting a broad spectrum activity against all selected bacterial in some cases. Mn(II), Co(II) and Ni(II) complexes of sulfanilamide Schiff base with the acetylpyrazolone derivative 4-acetyl-3-methyl-1-phenyl-2-pyrazolin-5-one sulfanilamide, exhibited a stronger and very good DPPH radical scavenging activity as good as ascorbic acid on comparing, but not with Cu(II). As such they could be important antitumour candidates.
- Full Text:
- Date Issued: 2014
Improving sanitization and fertiliser value of dairy manure and waste paper mixtures enriched with rock phosphate through combined thermophilic composting and vermicomposting
- Authors: Mupondi, Lushian Tapiwa
- Date: 2010
- Subjects: Compost , Vermicomposting , Manures , Biodegradation , Waste paper -- South Africa -- Eastern Cape , Thermophilic bacteria , Fertilizers
- Language: English
- Type: Thesis , Doctoral , PhD (Soil Science)
- Identifier: vital:11961 , http://hdl.handle.net/10353/411 , Compost , Vermicomposting , Manures , Biodegradation , Waste paper -- South Africa -- Eastern Cape , Thermophilic bacteria , Fertilizers
- Description: Thermophilic composting (TC) and vermicomposting (V) are the two most common methods used for biological stabilization of solid organic wastes. Both have their advantages and disadvantages but the proposed method of combining composting and vermicomposting (CV) borrows pertinent attributes from each of the two methods and combines them to enhance overall process and product qualities. Dairy manure and waste paper are two wastes produced in large quantities at the University of Fort Hare. The study was carried out to address the following specific objectives, to determine (i) the effectiveness of combined thermophilic composting and vermicomposting on the biodegradation and sanitization of mixtures of dairy manure and paper waste, (ii) an optimum precomposting period for dairy manure paper waste mixtures that results in vermicomposts of good nutritional quality and whose use will not jeopardize human health, (iii) the effectiveness of phosphate rock (PR) in increasing available P and degradation and nutrient content of dairy manure-paper vermicomposts, (iv) the physicochemical properties of vermicompost substituted pine bark compost and performance of resultant growing medium on plant growth and nutrient uptake. Results of this study revealed that wastes with a C: N ratio of 30 were more suitable for both V and CV as their composts were more stabilized and with higher nutrient contents than composts made from wastes with a C: N ratio of 45. Both V and CV were effective methods for the biodegradation of dairy manure and paper waste mixtures with C: N ratio of 30 but the latter was more effective in the biodegradation of waste mixtures with a C: N ratio of 45. The combinination of composting and vermicomposting eliminated the indicator pathogen E. coli 0157 from the final composts whereas V only managed to reduce the pathogen population. iv A follow up study was done to determine the effects of precomposting on pathogen numbers so as to come up with a suitable precomposting period to use when combine composting dairy manure-waste paper mixtures. Results of this study showed that over 95% of fecal coliforms, E. coli and of E. coli 0157 were eliminated from the wastes within one week of precomposting and total elimination of these and protozoan (oo)cysts achieved after 3 weeks of precomposting. The vermicomposts pathogen content was related to the waste’s precomposting period. Final vermicomposts pathogen content was reduced and varied according to precomposting period. Vermicomposts from wastes precomposted for over two weeks were less stabilized, less humified and had less nutrient contents compared to vermicomposts from wastes that were precomposted for one week or less. The findings suggest that a precomposting period of one week is ideal for the effective vermicomposting of dairy manure-waste paper mixtures. Results of the P enrichment study indicated an increase in the inorganic phosphate and a reduction in the organic phosphate fractions of dairy manure-waste paper vermicompost that were enriched with PR. This implied an increase in mineralization of organic matter and or solubilization of PR with vermicomposting time. Applying PR to dairy manure-waste paper mixtures also enhanced degradation and had increased N and P contents of dairy manure-waste paper vermicomposts. Earthworms accumulated heavy metals in their bodies and reduced heavy metal contents of vermicomposts. A study to determine the physicochemical properties of vermicompost substituted pine bark compost and performance of resultant growing medium on plant growth and nutrient uptake was done. Results obtained revealed that increasing proportions of dairy manure vermicomposts in pine bark compost improved tomato plant height, stem girth, shoot and root dry weights. v Tomatoes grew best in the 40 to 60% CV substituted pine bark and application of Horticote (7:2:1 (22)) fertilizer significantly increased plant growth in all media. Progressive substitution pine bark with dairy manure vermicomposts resulted in a decrease in the percentage total porosity, percentage air space whilst bulk density, water holding capacity, particle density, pH, electrical conductivity and N and P levels increased. Precomposting wastes not only reduced and or eliminated pathogens but also improved the stabilisation and nutrient content of dairy manure waste paper mixtures. The application of PR to dairy manure waste paper mixtures improved the chemical and physical properties of vermicomposts. Earthworms bio-accumulated the heavy metals Cd, Cr, Cu, Pb and Zn whilst the contents of these in the vermicomposts declined. It is, therefore, recommended that dairy manure waste paper mixtures be precomposted for one week for sanitization followed by PR application and vermicomposting for stabilization and improved nutrients contents of resultant vermicomposts. Substitution of pine bark compost with 40 to 60 % PR-enriched vermicompost produced a growing medium with superior physical and chemical properties which supported good seedling growth. However, for optimum seedling growth, supplementation with mineral fertilizer was found to be necessary.
- Full Text:
- Date Issued: 2010
Design, implementation and evaluation of a directly water cooled photovoltaic- thermal system
- Authors: Mtunzi, Busiso
- Date: 2013
- Subjects: Sensitivity analysis -- Photovoltaic thermal system (PV/T) , Solar utilization -- Carbon emission
- Language: English
- Type: Thesis , Doctoral , PhD (Physics)
- Identifier: vital:11597 , http://hdl.handle.net/10353/d1016198 , Sensitivity analysis -- Photovoltaic thermal system (PV/T) , Solar utilization -- Carbon emission
- Description: This research project was based on the Design, Implementation and Evaluation of a Photovoltaic Water heating system in South Africa, Eastern Cape Province. The purpose of the study was to design and investigate the scientific and economic contribution of direct water cooling on the photovoltaic module. The method involved performance comparison of two photovoltaic modules, one naturally cooled (M1) and the other, direct water cooled module (M2). Module M2 was used to produce warm water and electricity, hence, a hybrid system. The study focused on comparing the modules’ efficiency, power output and their performance. The temperatures attained by water through cooling the module were monitored as well as the electrical energy generated. A data logger and a low cost I/V characteristic system were used for data collection for a full year. The data were then used for performance analysis of the modules. The results of the study revealed that the directly water cooled module could operate at a higher electrical efficiency for 87% of the day and initially produced 3.63% more electrical energy each day. This was found to be true for the first three months after installation. In the remaining months to the end of the year M2 was found to have more losses as compared to M1 as evidenced by the modules’ performance ratios. The directly water cooled module also showed an energy saving efficiency of 61%. A solar utilization of 47.93% was found for M2 while 8.77% was found for M1. Economically, the project was found to be viable and the payback period of the directly cooled module (M2) system was found to be 9.8 years. Energy economics showed that the system was more sensitive to the price changes and to the energy output as compared to other inputs such as operation and maintenance and years of operation. A generation cost of R0.84/kWh from the system was found and when compared to the potential revenue of R1.18 per kWh, the system was found to enable households to make a profit of 40.5 %. Use of such a system was also found to be able to contribute 9.55% towards carbon emission reduction each year. From these results, it was concluded that a directly cooled photovoltaic/thermal heating (PV/T) system is possible and that it can be of much help in terms of warm water and electricity provision.
- Full Text:
- Date Issued: 2013
Analysis of the impact of Smallholder Irrigation Schemes on the choice of rural livelihood strategy and household food security in Eastern Cape
- Authors: Christian, Mzuyanda
- Date: 2017
- Subjects: Irrigation -- South Africa -- Eastern Cape Farms, Small -- South Africa -- Eastern Cape Food security -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/4813 , vital:28526
- Description: Since the end of Apartheid, the South African government has invested substantially in smallholder irrigation schemes, particularly in the former homeland areas. One of the primary goals for establishment of these schemes was to solve food security problems. Sadly, these efforts have not produced the desired results, and poverty has deepened. The question that can be asked is: What is it that makes South African smallholder agricultural sector seemingly impervious to the interventions that government has made in targeting smallholder farmers since the dawn of democracy in 1994? In order to address such a question, a set of structured questionnaires was used to interview 100 smallholder irrigators and 100 non-irrigators using multistage stratified random sampling technique in the Amatole, Chris Hani and OR Tambo District municipalities. Demographic and socio-economic characteristics of smallholder irrigators and non-irrigators around Qamata, Pendu, Tyhefu, Merelles and Ntshongweni irrigation schemes were measured using descriptive statistics. Profitability between the two groups was measured using gross margin analysis (GM). The Probit model was used to determine the factors that affect smallholder farmer‘s choice of participation in irrigation schemes. The impact of irrigation participation on yields, crop sales and food security was estimated using the propensity score matching (PSM) technique. The impact of irrigation participation of smallholder farmer‘s choice of livelihood strategy was estimated using the multinomial regression model. The results showed that male respondents were dominant with a representation of 63 percent and average mean household size of 4 persons with the household head having spent at least 7 years at school. Farming was found to be the major (64 percent) occupation in the study area with an average income of R2 944.52 per cropping season. Both irrigating and non-irrigating smallholder farmers in the study area used improved, fertilizer and tractor for production. Overall, smallholder farmers spent 30.9 percent of their household income on food with irrigators‘food spending lower than those of non-irrigators. The gross margin analysis suggests that the irrigated farmers were in a better position to afford enough food in order to satisfy their household requirement. Findings from the Probit regression and Propensity Score Matching are consistent across the methods, indicating that irrigation participation has a positive influence on crop yields, income and consumption expenditure. Probit regression further showed that age, quality of land, access to credit, access to market, distance to the scheme and membership of another society/association have a positive impact on access and use of irrigation and are significant at p < 0.05 percent level. The Propensity Score Matching using Nearest Neighbour and Kernel Matching Methods of the outcome variables, total farm income and food consumption patterns, shows a positive and statistically significant result at p < 0.05 percent level. The nearest neighbour matching method shows that irrigators received higher farm income R2044.01 than non-irrigating farmers R622.12. The Average Treatment Effect on total food expenditure was negative both in the case of NNM and KM algorithms, indicating that participation in irrigation can decrease the expenditure levels on food from R933.30 to R926.70. This could be due to the fact that irrigating farmers produced enough for home consumption than non-irrigators. The multinomial regression model shows that irrigation participation influences smallholder farmers choice of livelihood strategy and these variables were statistically significant at p < 0.05 percent level. These results provide insights to address the question as to the appropriate development path for transition from homestead to irrigation. Continued support to smallholder farmers in the forms of funding, extension services and improved technologies is certainly needed to enhance food security.
- Full Text:
- Date Issued: 2017
The competitiveness of the South African citrus industry in the face of the changing global health and environmental standards
- Authors: Ndou, Portia
- Date: 2012
- Subjects: Citrus fruit industry -- South Africa , Food industry and trade -- Safety regulations , Agricultural industries -- Safety regulations , Food -- Safety measures -- International cooperation , Export marketing -- Law and legislation -- South Africa , Competition, International
- Language: English
- Type: Thesis , Doctoral , PhD (Agricultural Economics)
- Identifier: vital:11162 , http://hdl.handle.net/10353/477 , Citrus fruit industry -- South Africa , Food industry and trade -- Safety regulations , Agricultural industries -- Safety regulations , Food -- Safety measures -- International cooperation , Export marketing -- Law and legislation -- South Africa , Competition, International
- Description: In recent years, concern about food safety linked to health issues has seen a rise in private food safety standards in addition to the regulations set by the Food and Agriculture Organisation (FAO) in collaboration with the World Health Organisation (WHO). These have presented challenges to producers and exporters of agricultural food products especially the producers of fresh fruits and vegetables. In spite of the food safety-linked challenges from the demand side, the vast range of business-environment forces pose equally formidable challenges that negatively impact on the exporting industries’ ability to maintain or improve their market shares and their ability to compete in world markets. The objective of this study was therefore to establish the competitiveness of the South African citrus industry in the international markets within this prevailing scenario. Due to the diversity of the definitions of competitiveness as a concept, this study formulated the following working definition: “the ability to create, deliver and maintain value and constant market share through strategic management of the industrial environment or competitiveness drivers”. This was based on the understanding that the international market shares of an industry are a function of forces in the business environment which range from intra-industry, external and national as well as the international elements. The unit of analysis were the citrus producers engaged in export of their products and the study made use of 151 responses by producers. The study adopted a five-step approach to the analysis of the performance of the South African citrus industry in the global markets, starting with the analysis of the Constant Market Share (CMS) of the South African citrus industry in various world markets, establishing the impact of the business environmental factors upon competitiveness, establishing the costs of compliance with private food safety standards, determining the non-price benefits of compliance with the standards, as well as highlighting the strategies for enhancing long-term competitiveness of the industry in the international markets. South Africa is one of the top three countries dominating the citrus fruit export market. Since its entry into the citrus fruit exports market in the 1900s, the industry has sustained its activity in the international market. The Constant Market Share Analysis shows that, amidst the challenges on the international market side, and the changes in the business environment, over much of which the industry has limited control and influence, the industry has maintained its competitive advantage in several markets. The CMS shows that South Africa’s lemons are competitive in America. Despite a negative trend, the South African grapefruit has been competitive in France, Greece, Italy, the Netherlands and Spain. Oranges have been competitive in the Greece, Italy, Portugal, UK, Asian and Northern Europe markets. Competitiveness in these markets has been due to the inherent competitiveness of the industry. Competitiveness in such markets as the Middle East has been attributed to the relatively rapid growth of these markets. The South African citrus industry has similarly undergone many major processes of transformation. The business environmental factors influencing its performance have ranged reform to the challenges beyond the country’s borders. These factors directly and indirectly affect the performance of the industry in the export market. They have influenced the flow of fruits into different international destinations. Of major concern are the food safety and private standards. Challenges in traditional markets as well as opportunities presented by demand from newly emerging citrus consuming nations have seen a diversification in the marketing of the South African citrus. The intensity of competition in the global market is reflected by the fluctuations in the market shares in different markets as well as the increase and fluctuations of fruit rejection rates in some lucrative markets such as America. A combination of challenging national environmental forces and stringent demand conditions negatively impact on revenues especially from markets characterised by price competitiveness. This study identified cost of production, foreign market support systems, adaptability, worker skills, challenges of management in an international environment and government policies such as labour and trade policies as some of the most influential obstacles to competitiveness. Some of the most competiveness-enhancing factors were market availability, market size, market information, market growth and the availability of research institutions. However, compliance with private standards still poses a challenge to the exporters. The different performance levels of the industry in various markets prove the dissimilarity of the demand conditions in the global market. These are supported by the negative influence associated with the foreign market support regimes as well as the challenges associated with compliance with private food safety standards. While market availability, market growth, market information and size were identified as enhancing competitiveness, the fluctuations and inconsistencies in the competitiveness of the industry in different foreign markets require more than finding markets. Resource allocation by both the government and the industry may need to take into account the off-setting of the national challenges and support of farmers faced with distorted and unfair international playing fields. Otherwise, market availability is not a challenge for the industry save meeting the specifications therewith as well as price competitiveness which is unattainable for the South African citrus producers faced with high production costs. For the purposes of further study, it is recommended that account should be taken of all the products marketed by the industry (including processed products such as fruit juices) in order to have a whole picture of the competitiveness of the industry in the international market. This study also proffers a new theoretical framework for the analysis of the business environment for the citrus industry and other agro-businesses. This framework takes into account the indispensability of the food safety standards and measures as well as the diversity of the global consumer and the non-negotiability of food trade for the sustenance of the growing population.
- Full Text:
- Date Issued: 2012
Qualitative and quantitative properties of solutions of ordinary differential equations
- Authors: Ogundare, Babatunde Sunday
- Date: 2009
- Subjects: Differential equations , Lyapunov functions , Chebyshev polynomials , Algorithms
- Language: English
- Type: Thesis , Doctoral , PhD (Applied Mathematics)
- Identifier: vital:11588 , http://hdl.handle.net/10353/244 , Differential equations , Lyapunov functions , Chebyshev polynomials , Algorithms
- Description: This thesis is concerned with the qualitative and quantitative properties of solutions of certain classes of ordinary di erential equations (ODEs); in particular linear boundary value problems of second order ODE's and non-linear ODEs of order at most four. The Lyapunov's second method of special functions called Lyapunov functions are employed extensively in this thesis. We construct suitable complete Lyapunov functions to discuss the qualitative properties of solutions to certain classes of non-linear ordinary di erential equations considered. Though there is no unique way of constructing Lyapunov functions, We adopt Cartwright's method to construct complete Lyapunov functions that are required in this thesis. Su cient conditions were established to discuss the qualitative properties such as boundedness, convergence, periodicity and stability of the classes of equations of our focus. Another aspect of this thesis is on the quantitative properties of solutions. New scheme based on interpolation and collocation is derived for solving initial value problem of ODEs. This scheme is derived from the general method of deriving the spline functions. Also by exploiting the Trigonometric identity property of the Chebyshev polynomials, We develop a new scheme for approximating the solutions of two-point boundary value problems. These schemes are user-friendly, easy to develop algorithm (computer program) and execute. They compare favorably with known standard methods used in solving the classes of problems they were derived for
- Full Text:
- Date Issued: 2009
Adaptation choices, community perceptions, livelihood linkages and income dynamics for district producer communities surrounding Nyatana Game Park in Zimbabwe
- Authors: Taruvinga, Amon
- Date: 2011
- Subjects: Game reserves -- Zimbabwe , Wildlife conservation -- Zimbabwe , Wildlife management -- Zimbabwe , Sustainable development -- Zimbabwe , Game farms -- Zimbabwe , Rural poor -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD (Agricultural Economics)
- Identifier: vital:11154 , http://hdl.handle.net/10353/476 , Game reserves -- Zimbabwe , Wildlife conservation -- Zimbabwe , Wildlife management -- Zimbabwe , Sustainable development -- Zimbabwe , Game farms -- Zimbabwe , Rural poor -- Zimbabwe
- Description: This thesis explores human-wildlife interactions under community managed game parks. The thesis consists of an introductory chapter, study location chapter and four self-contained studies based on different samples from created clusters surrounding Nyatana Game Park, which make up the rest of the thesis chapters. Chapter one presents an introductory overview of wildlife management in Zimbabwe, specifically looking at human-wildlife interactions under CAMPFIRE projects, welfare dynamics and conservation implications for the surrounding communities who share boundaries with community-managed game parks. The chapter concludes by highlighting the challenges facing community-based wildlife conservation in Zimbabwe as well as the key concepts that will be the subject of the rest of the thesis. Chapter two presents the study location; it highlights the road map to the study area, starting with the provincial location, and indicates the specific districts from which respondents were selected. A brief agro-ecological summary of the study area is also presented; it looks specifically at climate, vegetation and a demographic data of the study area. Chapter three: Can game parks be trusted as livelihood sources? To answer this topical question, Chapter three explores livelihood adaptation strategies for households who share boundaries with Nyatana Game Park. Most of the community managed game parks, under CAMPFIRE principles in Zimbabwe, were established with the primary objective of generating revenue for the surrounding communities; this was done in the hope of using positive returns from game farming to promote the conservation of wildlife. Has this materialised in practice? Descriptive results from this study seem to suggest otherwise, where mixed farming and gold panning were the major livelihood adaptation choices reported by most households. The revenue from game farming was reported to be too low and inconsistent, to such an extent that the majority of the community regarded it as risky and unreliable. A multinomial logistic regression model for correlates of adaptation choices indicated that access to credit, markets, and extension may be some of the current institutional constraints inhibiting households from accessing off-farm sources for their livelihoods. In addition, household size, gender and age may enhance the adaptive capacity of households to move out of risky crop faming into other off-farm portfolio diversifications. The study, therefore, suggests that game parks, according to the evidence uncovered by the study, may not be trusted as a reliable and sustainable livelihood source. If local communities who share boundaries with game parks do not view them as reliable and sustainable livelihood sources, as concluded in Chapter three, how can they (local communities) be trusted to conserve them? To assess their perceptions of game parks, Chapter four presents a multinomial logistic regression model for perceptions of society on game parks using the African elephant as a typical example. The results suggest that Problem Animal Control (PAC) perceptions, livestock predation and issues of low and poor revenue distribution may be some of the critical perceptions capable of influencing surrounding communities to negatively participate in the conservation of wildlife. The results further suggest that using wildlife proceeds to finance observable local common pool infrastructure may positively influence the surrounding communities to conserve wildlife. The chief conclusion regarding game parks, therefore, was that the surrounding communities were in favour of the obliteration pathway, although minimal conservation perceptions were also available. Given the negative conclusions regarding game parks, as suggested in Chapters three and four, citizens would then wonder if any meaningful hope for community managed game parks exists. Chapter five probes the buffer zone livelihood link under community managed game parks, using evidence from the Nyatana Game Park. The binary logistic regression model results, for buffer zone participation and resource extraction combinations by surrounding communities, suggest that resource extraction may be market driven rather than focussing on domestic consumption. The study therefore concludes that the buffer zone livelihood link as currently practiced, though potential, may fail to address the livelihood expectations of the sub-district producer communities. The study therefore calls for extreme caution whenever the buffer zone livelihood link is considered, because several institutional and design conflicts exist within this dynamic. In Chapter six, the study further probed the buffer zone income dynamics for the sub-district producer community. The results of descriptive statistics suggest that the contribution of buffer zone activities to household income may be significant with a positive correlation to household agricultural income for communities who reside inside or close to the park (primary sub-district producer community). Using the Gini decomposition approach and Lorenz curves, the study concluded that a buffer zone income may be capable of contributing to more equally distributed incomes for rural communities who share boundaries with game parks. With respect to the correlates of household income, the results suggest that household size and age may negatively influence income from buffer zone activities, while gender may have a positive effect. This was also true for education and Livestock Units (LUs) with respect to income from self employment; the former positively and the latter negatively related. The results further suggest that land size may also be positively significant in order to explain income from agriculture as well as total income. With regard to the distance from the buffer zone, the results suggest a negative influence with respect to the buffer zone, agriculture and total income. The implied message therefore suggests that buffer zones may provide active livelihood sources which are capable of financing rural household agriculture. The income equalizing effect which is portrayed may also further imply that, if correctly targeted and promoted, a buffer zone income could possibly address the current income inequality which is generic in rural areas. However, this potential may not be realized due to the current buffer zone design status (created for local secondary use as opposed to commercial primary use), restrictive policies and poor institutional support. With this dilemma facing community managed game parks (threats as summarised in Chapters three and four amid the potential hope summarized in Chapters five and six), Chapter 7 concludes the study by suggesting that the human-wildlife interaction model, though currently theoretical, may have significant practical potential in addressing the livelihoods of the surrounding communities as well as promoting the conservation of wildlife. This could be possible if available challenges that range from low revenue, insecure property rights, high human-elephant conflict and institutional design conflict for buffer zone utilization are corrected by means of the free market system. This would allow market forces to deliver on the expectations of the ―human-wildlife interactions model‖ – sustainable livelihoods for the former and intergenerational conservation for the latter.
- Full Text:
- Date Issued: 2011
Bioconditioning and nitrogen fertility effects of selected cyanobacteria strains on two degraded soils in the Eastern Cape Province, South Africa
- Authors: Maqubela, Mfundo Phakama
- Date: 2009
- Subjects: Nostoc , Cyanobacteria , Soil fertility -- Testing , Soils -- Nitrogen content , Cyanobacteria -- Biotechnology
- Language: English
- Type: Thesis , Doctoral , PhD (Soil Science)
- Identifier: vital:11959 , http://hdl.handle.net/10353/558 , Nostoc , Cyanobacteria , Soil fertility -- Testing , Soils -- Nitrogen content , Cyanobacteria -- Biotechnology
- Description: Some cyanobacteria strains have biofertilization and bioconditioning effects in soils. The objective of this study was to identify cyanobacteria with potential to improve the N fertility and structural stability of degraded soils and evaluate their effectiveness in soils of the Eastern Cape, South Africa. Isolation and characterization of the indigenous cyanobacteria strains with desirable properties was first to be undertaken because their effects are known to differ from strain to strain. Cyanobacteria strains 3g, 3v, and 7e were identified from 97 strains isolated from selected soils. Nostoc strains 3g and 3v had greater ability to produce exocellular polysaccharides (EPS) but low potential to fix atmospheric N2 (4.7 and 1.3 nmol C2H4 μg chl-1 h-1, respectively). On the other hand, strain 7e had the highest capability to fix atmospheric N2 (16.1 nmol C2H4 μg chl-1 h-1) but had the least ability to produce EPS. Evaluation of the strains was done in glasshouse studies starting with Nostoc strain 9v isolated from a Tanzanian soil, followed by the indigenous strains isolated from soils in Hertzog and Qunu, South Africa. Inoculation was done by uniformly applying cyanobacteria on the surface of potted soils at a rate of 6 g m-2. First harvest and soil sampling took place after six weeks, and the top 25 mm of the soil was mixed, replanted, and sampled again after a further six weeks (second harvest). Inoculation with Nostoc strain 9v increased soil N by 40 percent and 17 percent in Guquka and Hertzog soils, respectively, and consequently increased maize dry matter yields by 40 and 49 percent. Soil C increased by 27 percent and 8 percent in Guquka and Hertzog soils, respectively, and this increase was significantly associated with that of soil N (R2 = 0.838). Higher contents of soil C, soil N and mineral N, however, were found in non-cropped soils. Scanning Electron Microscopy (SEM) revealed coatings of EPS on soil particles and fragments of non-cropped inoculated soils, with iii other particles enmeshed in networks of filaments, in contrast to cropped and/or non-inoculated soils. The proportion of very stable aggregates was increased by inoculation but cropping with maize reduced the aggregate stability. Inoculating Hertzog soil with indigenous strains 3g and 7e increased the nitrate N in the first cropping by 49 percent and 69 percent respectively, in cropped soils. In the second cropping increases in mineral N were 41 percent and 43 percent in 3g and 7e inoculated soils, respectively. Maize dry matter yields were higher on inoculated soils both in the first and second harvest in response to the improved N status of the soil. Increases in aggregate MWD in cropped soil as determined by fast wetting, mechanical breakdown and slow wetting were 85 percent, 33 percent, 33 percent, respectively, for 3g inoculation, 64 percent, 41 percent, and 41 percent, respectively, for 7e inoculation and 60 percent, 24 percent, 50 percent for inoculation with 9v. In non-cropped soil, increases in MWD as determined by fast wetting, mechanical breakdown and slow wetting were 11 percent, 0 percent, 7 percent, respectively for 3g inoculation, 21 percent, 11 percent, and 7 percent, respectively for 7e inoculation, and 25 percent, 36 percent, and 19 percent for strain 9v inoculation. Scanning electron microscopy observations, which were confirmed by chemical results, revealed that inoculated soils had high EPS and filaments that encouraged soil aggregation and improved aggregate stability. Results of this study show that cyanobacteria strains isolated and selected for their ability to fix atmospheric N2 and produce EPS improved the fertility status and aggregate stability of degraded soils from South Africa.
- Full Text:
- Date Issued: 2009
Sedimentary, geochemical and geophysical study of the Ecca group, Karoo supergroup and its hydrocarbon potential in the Eastern Cape Province, South Africa
- Authors: Baiyegunhi, Christopher
- Date: 2017
- Subjects: Sediments (Geology) -- South Africa -- Eastern Cape Sedimentology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/4881 , vital:28658
- Description: The Ecca Group of Karoo Supergroup is a sedimentary rock sequence that deposited between the Late Carboniferous (Dwyka Group) and the Late Permian-Middle Triassic (Beaufort Group). The Ecca Group investigated in this study is situated in the Eastern Cape Province of South Africa and it comprises mainly of shales, mudstones, siltstones and sandstones. The Ecca Group sequence contains considerable carbon content and suitable thickness to make it an ideal target for shale gas exploration. Previous studies put more emphasis on the geology and stratigraphy of the Ecca Group, this study revised the stratigraphy, and put new insight on the petrography, depositional processes, sedimentary facies, provenance, paleoweathering, tectonic setting, subsidence rates and history, electrical resistivity, source rock characteristics and diagenesis of the potentially feasible sandstone and mudrock reservoir rocks of the Ecca Group. Based on the lithological features, sedimentary structures and facies characteristics, the stratigraphy of the Prince Albert, Whitehill, Collingham and Fort Brown Formations of the Ecca Group is now subdivided into two informal members each, i.e. Lower Member and Upper Member. Furthermore, the Ripon Formation is now subdivided into three informal members. Each member has been asigned a lithological name. The grain size parameters show that most of the Ecca Group sandstones are very fine to fine grained, poorly to moderately well sorted, mostly near-symmetrical and mesokurtic in grain-size distribution. The linear discriminant function analysis is dominantly indicative of turbidity current deposits under deep marine environment for Prince Albert, Whitehill and Collingham Formations, shallow marine environment for Ripon Formation, while the Fort Brown Formation is lacustrine-deltaic deposits. Modal composition analysis and petrography studies revealed that the detrital components of the sandstones are dominated by monocrystalline quartz, feldspar and lithic fragments. The sandstones are compositionally and texturally immature and can be classified as feldspathic wacke and lithic wacke. The provenance analysis revealed plutonic and metamorphic terrains as the main source rocks with minor debris derived from recycled sedimentary rocks. The detrital modal compositions of these sandstones are related to back arc to island and continental margin of tectonic setting. Based on the detailed sedimentological analyses of outcrop and borehole data, fourteen lithofacies were identified and seven facies associations (FAs) were recognised. The facies associations are: FA 1: Shale and mudstones intercalated with siltstones, FA 2: Carbonaceous shale, mudstone with subordinate chert and sandstone, FA 3: Mudstones rhythmite with thin bedded mudstone and lenticular siltstone, FA 4: Greyish medium bedded sandstone intercalated with laminated mudstone, FA 5: Dark-grey medium to thick bedded mudstone and siltstone, FA 6: Thin to medium bedded sandstone alternated with thin bedded carbonaceous mudstone, and FA 7: Varved mudstone rhythmite intercalated with siltstone and minor sandstone. Sedimentological characteristics of the identified facies associations indicate four deposition environments, namely, deep marine basin, turbidite, shallow marine and lacustrine environments, which constitute a gradually regression sequence as a result of sea-level dropping and shallowing of the basin during the developmental processes. Geochemical analysis of the Ecca mudrocks and sandstones revealed that the rocks are of quartzose sedimentary provenance, suggesting that they were derived from a cratonic interior or recycled orogen. The petrography and geochemistry of the sandstones indicated that the source areas are composed of plutonic and metamorphic rocks with a minor component from sedimentary rocks. The geochemical diagrams and indices of weathering suggested that the granitic source rocks underwent moderate to high degree of chemical weathering. The tectonic setting discrimination diagrams support passive continental margin setting of the provenance.
- Full Text:
- Date Issued: 2017