Bacterial degradation of waste coal
- Authors: Madikiza, Lwazikazi
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/54576 , vital:26590
- Description: As an energy source coal has one of the largest agglomerations in the world. Consequently mining of coal creates large volumes of waste in the form of low ranks coals. The complex structure of coal makes it difficult for the microorganisms to degrade and relatively few bacteria and fungi have been shown to break down coal. This study aimed to investigate bacteria not previously known to degrade coal. In this study bacteria were isolated from hydrocarbon contaminated sites and inoculated in coal medium where coal served as the only carbon source. Three strains produced a yellow – brown supernatant after 14 d of incubation at 30 °C. Bacteria generating a yellow – brown coloured supernatant were presumed to possess coal degrading capabilities and the best performing of these bacterial species was identified using 16s rDNA as Bacillus flexus. Scanning electron microscopy showed that there was a close association between the bacterium and substrate coal. The close association of bacteria to substrate suggested that these organisms were able to maximize solubilisation. FT-IR spectroscopic analysis demonstrated the addition of single bonded compounds COOH, OH, CN and CH that were absent prior to bacterial interaction. The increase in oxygen rich regions indicated degradation of the coal substrate. Elemental analysis showed that there was a decrease in carbon content from 47 % to 24 % during the 14 day incubation period. Reduction in coal carbon content was assumed to be due to bacterial utilization for metabolism and growth particularly as untreated coal substrate showed minimal loss of carbon. Analysis of the residual culture medium revealed that there was a linear increase in humic-like substance concentration for 8 d, coincident with increased coal biosolubilisation and colour change. Laccase activity was insignificant, and at 13 d enzyme activity was only 5×10-3 U/L suggesting that B. flexus may use a different mechanism to degrade coal. Residual culture medium remaining after bacterial action on the coal substrate appeared to possess plant growth promoting activity. This soluble biodegradation product with characteristics similar to humic acid-like substances was shown to impact growth of radish cotyledons. Expansion of isolated radish cotyledons was enhanced by 140% when incubated in coal biodegradation product. In conclusion, this study has yielded B. flexus and two other unidentified bacteria, isolated from polyaromatic hydrocarbon contaminated soils, and demonstrated the ability of these microorganisms to degrade waste coal. Further studies to elucidate the mechanism of coal breakdown by B. flexus, synergies with other coal degrading microorganisms, and incorporation of bacterium into Fungcoal bioprocess technology is imminent.
- Full Text:
- Authors: Madikiza, Lwazikazi
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/54576 , vital:26590
- Description: As an energy source coal has one of the largest agglomerations in the world. Consequently mining of coal creates large volumes of waste in the form of low ranks coals. The complex structure of coal makes it difficult for the microorganisms to degrade and relatively few bacteria and fungi have been shown to break down coal. This study aimed to investigate bacteria not previously known to degrade coal. In this study bacteria were isolated from hydrocarbon contaminated sites and inoculated in coal medium where coal served as the only carbon source. Three strains produced a yellow – brown supernatant after 14 d of incubation at 30 °C. Bacteria generating a yellow – brown coloured supernatant were presumed to possess coal degrading capabilities and the best performing of these bacterial species was identified using 16s rDNA as Bacillus flexus. Scanning electron microscopy showed that there was a close association between the bacterium and substrate coal. The close association of bacteria to substrate suggested that these organisms were able to maximize solubilisation. FT-IR spectroscopic analysis demonstrated the addition of single bonded compounds COOH, OH, CN and CH that were absent prior to bacterial interaction. The increase in oxygen rich regions indicated degradation of the coal substrate. Elemental analysis showed that there was a decrease in carbon content from 47 % to 24 % during the 14 day incubation period. Reduction in coal carbon content was assumed to be due to bacterial utilization for metabolism and growth particularly as untreated coal substrate showed minimal loss of carbon. Analysis of the residual culture medium revealed that there was a linear increase in humic-like substance concentration for 8 d, coincident with increased coal biosolubilisation and colour change. Laccase activity was insignificant, and at 13 d enzyme activity was only 5×10-3 U/L suggesting that B. flexus may use a different mechanism to degrade coal. Residual culture medium remaining after bacterial action on the coal substrate appeared to possess plant growth promoting activity. This soluble biodegradation product with characteristics similar to humic acid-like substances was shown to impact growth of radish cotyledons. Expansion of isolated radish cotyledons was enhanced by 140% when incubated in coal biodegradation product. In conclusion, this study has yielded B. flexus and two other unidentified bacteria, isolated from polyaromatic hydrocarbon contaminated soils, and demonstrated the ability of these microorganisms to degrade waste coal. Further studies to elucidate the mechanism of coal breakdown by B. flexus, synergies with other coal degrading microorganisms, and incorporation of bacterium into Fungcoal bioprocess technology is imminent.
- Full Text:
The feasibility of forming a monetary union in SADC : meeting convergence and optimum currency area criteria and evaluating fiscal sustainability
- Authors: Mokoena, Motshidisi Suzan
- Date: 2013
- Subjects: Southern African Development Community Economic and Monetary Union Common Monetary Area (Organization) Economic policy -- Africa, Southern Monetary policy -- Africa, Southern Monetary unions
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1073 , http://hdl.handle.net/10962/d1007743
- Description: In conformity with the goal of the African Union to build a monetary union for the entire African continent, one of the goals of the Southern African Development Community (SADC) is the formation of a monetary union with a single central bank. Towards this end certain macroeconomic convergence criteria, which are closely aligned with those used by the European Union (EU), have been set. While empirical research on whether or not SADC would benefit from the formation of a currency union has focused on the optimum currency area criteria, no reference to these criteria is made in the SADC programme. Instead, the SADC approach has been governed by a set of macroeconomic convergence criteria synonymous with those pursued by the European Monetary Union (EMU) prior to its formation. Doubts regarding the future of the EU have recently been raised as a result of debt crises in certain member states, implicitly raising questions about the adequacy of the convergence criteria that were adopted. Accordingly, this study considers the feasibility of establishing a currency union in the SADC region. The proposed convergence criteria are assessed against the theory of optimum currency areas as well as in terms of their adequacy in the light of recent EU experience. In addition, the paper provides a preliminary assessment of the fiscal sustainability of the SADC region by conducting Engle-Granger cointegration tests on the public debt and revenue series for the SADC countries under analysis. It was observed that SADC has made considerable progress towards meeting its macroeconomic convergence criteria in recent years. However, in light of the regions' heavy dependence on commodity exports coupled with recent price fluctuations in this regard, the sustainability of this progress is questioned. Furthermore, a review of the EMU experience to date highlights numerous flaws in its approach and the potential challenges the SADC region should consider in moving forward with its agenda. In essence, the study suggests that almost all the SADC member states are fiscally unprepared for monetary union formation and the recent EMU debt crisis has highlighted the importance of acquiring a state of fiscal sustainability prior to union formation. In addition, it is imperative that the SADC members continue to address issues of product diversification, intraregional trade and political unification, all of which should be governed by a centralised fiscal authoriry.
- Full Text:
- Authors: Mokoena, Motshidisi Suzan
- Date: 2013
- Subjects: Southern African Development Community Economic and Monetary Union Common Monetary Area (Organization) Economic policy -- Africa, Southern Monetary policy -- Africa, Southern Monetary unions
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1073 , http://hdl.handle.net/10962/d1007743
- Description: In conformity with the goal of the African Union to build a monetary union for the entire African continent, one of the goals of the Southern African Development Community (SADC) is the formation of a monetary union with a single central bank. Towards this end certain macroeconomic convergence criteria, which are closely aligned with those used by the European Union (EU), have been set. While empirical research on whether or not SADC would benefit from the formation of a currency union has focused on the optimum currency area criteria, no reference to these criteria is made in the SADC programme. Instead, the SADC approach has been governed by a set of macroeconomic convergence criteria synonymous with those pursued by the European Monetary Union (EMU) prior to its formation. Doubts regarding the future of the EU have recently been raised as a result of debt crises in certain member states, implicitly raising questions about the adequacy of the convergence criteria that were adopted. Accordingly, this study considers the feasibility of establishing a currency union in the SADC region. The proposed convergence criteria are assessed against the theory of optimum currency areas as well as in terms of their adequacy in the light of recent EU experience. In addition, the paper provides a preliminary assessment of the fiscal sustainability of the SADC region by conducting Engle-Granger cointegration tests on the public debt and revenue series for the SADC countries under analysis. It was observed that SADC has made considerable progress towards meeting its macroeconomic convergence criteria in recent years. However, in light of the regions' heavy dependence on commodity exports coupled with recent price fluctuations in this regard, the sustainability of this progress is questioned. Furthermore, a review of the EMU experience to date highlights numerous flaws in its approach and the potential challenges the SADC region should consider in moving forward with its agenda. In essence, the study suggests that almost all the SADC member states are fiscally unprepared for monetary union formation and the recent EMU debt crisis has highlighted the importance of acquiring a state of fiscal sustainability prior to union formation. In addition, it is imperative that the SADC members continue to address issues of product diversification, intraregional trade and political unification, all of which should be governed by a centralised fiscal authoriry.
- Full Text:
Promoting learners' conceptual understanding of electrostatics through use of practical activities in conjunction with prior knowledge of lightning : a case study
- Authors: Maselwa, Matole Reuben
- Date: 2004
- Subjects: Electrostatics -- Study and teaching -- Case studies Science -- Study and teaching -- Case studies Lightning -- Study and teaching -- Case studies
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1717 , http://hdl.handle.net/10962/d1003600
- Description: The research presented in this thesis is situated within an interpretivist paradigm. Within this paradigm, a qualitative case-study research approach was adopted. This seemed most appropriate in my research project since the main focus is on elicitation of prior knowledge and incorporation of such knowledge into 'hands-on' and 'minds-on' practical activities with a view to improving conceptual development. For the purposes of this research project, I designed an interactive teaching and learning unit in electrostatics as an attempt to put into practice a learner-centred approach. This approach, in my view, is in line with the new curriculum in South Africa. The emerging central theme of this thesis is the notion of active participation by learners during teaching and learning. This study was carried out over a period of two years and involved my grade 9 learners, who participated voluntarily. The research process documented in this thesis has been conceptualised into two phases. Phase one was concerned with the elicitation of learners' prior knowledge around lightning. In phase two, learners were engaged in 'hands-on' and 'minds-on' practical activities, and key concepts were identified to ensure conceptual development. The data was collected using a variety of data collection tools, namely: focus group interviews, follow-up whole-class semi-structured interviews, worksheets, videotaped lessons and photographs. The analysis of data revealed that learners come to class with prior knowledge concerning lightning. Within this prior knowledge it was found that there were both ‘scientific’ and ‘non-scientific’ concepts. The identification of key concepts during practical activities was found to be very useful in promoting learning. However, the incorporation of prior knowledge into practical activities posed a challenge and needs further research. iv This research study also highlights some insights into some of the complexities of elicitation and incorporation of learners' prior knowledge, and conceptual development in science classrooms. It also demonstrates the challenges and possibilities during teaching and learning as well as the realities of the demands of the new curriculum and OBE in South Africa, in particular, in historically disadvantaged schools
- Full Text:
- Authors: Maselwa, Matole Reuben
- Date: 2004
- Subjects: Electrostatics -- Study and teaching -- Case studies Science -- Study and teaching -- Case studies Lightning -- Study and teaching -- Case studies
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1717 , http://hdl.handle.net/10962/d1003600
- Description: The research presented in this thesis is situated within an interpretivist paradigm. Within this paradigm, a qualitative case-study research approach was adopted. This seemed most appropriate in my research project since the main focus is on elicitation of prior knowledge and incorporation of such knowledge into 'hands-on' and 'minds-on' practical activities with a view to improving conceptual development. For the purposes of this research project, I designed an interactive teaching and learning unit in electrostatics as an attempt to put into practice a learner-centred approach. This approach, in my view, is in line with the new curriculum in South Africa. The emerging central theme of this thesis is the notion of active participation by learners during teaching and learning. This study was carried out over a period of two years and involved my grade 9 learners, who participated voluntarily. The research process documented in this thesis has been conceptualised into two phases. Phase one was concerned with the elicitation of learners' prior knowledge around lightning. In phase two, learners were engaged in 'hands-on' and 'minds-on' practical activities, and key concepts were identified to ensure conceptual development. The data was collected using a variety of data collection tools, namely: focus group interviews, follow-up whole-class semi-structured interviews, worksheets, videotaped lessons and photographs. The analysis of data revealed that learners come to class with prior knowledge concerning lightning. Within this prior knowledge it was found that there were both ‘scientific’ and ‘non-scientific’ concepts. The identification of key concepts during practical activities was found to be very useful in promoting learning. However, the incorporation of prior knowledge into practical activities posed a challenge and needs further research. iv This research study also highlights some insights into some of the complexities of elicitation and incorporation of learners' prior knowledge, and conceptual development in science classrooms. It also demonstrates the challenges and possibilities during teaching and learning as well as the realities of the demands of the new curriculum and OBE in South Africa, in particular, in historically disadvantaged schools
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Pottery craft and culture
- Authors: Randell, Gillian
- Date: 1972
- Subjects: Pottery craft
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2452 , http://hdl.handle.net/10962/d1007559
- Description: "The idea and fact of containment have been the primary significance of pottery from the beginning, and pots of all ages and peoples, even when their ostensible function was ceremonial or symbolical, have expressed by their generous swelling volumes, the potential or holding things of vital importance to man food, liquid or the furnishings of the grave." The utilitarian value of a pot is inseparable from its aesthetic quality. "There can be no fullness of complete realization or utility without beauty, refinement and charm, for the simple reason that their absence must in the long run be intolerable to both maker and consumer... The continued production of utilities without delight in making and using is bound to produce only boredom and to end in sterility." Modern pottery, whether industrial or that of the artist potter, has each in its different way tended to separate the aesthetic and the utilitarian. This is one symptom of the cultural decline of our Western tradition since the Eighteenth Century. The making of pots has persisted from earliest times to the present day through our ever changing world. Circumstances have at times obscured the essential truths of this art.
- Full Text:
- Authors: Randell, Gillian
- Date: 1972
- Subjects: Pottery craft
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2452 , http://hdl.handle.net/10962/d1007559
- Description: "The idea and fact of containment have been the primary significance of pottery from the beginning, and pots of all ages and peoples, even when their ostensible function was ceremonial or symbolical, have expressed by their generous swelling volumes, the potential or holding things of vital importance to man food, liquid or the furnishings of the grave." The utilitarian value of a pot is inseparable from its aesthetic quality. "There can be no fullness of complete realization or utility without beauty, refinement and charm, for the simple reason that their absence must in the long run be intolerable to both maker and consumer... The continued production of utilities without delight in making and using is bound to produce only boredom and to end in sterility." Modern pottery, whether industrial or that of the artist potter, has each in its different way tended to separate the aesthetic and the utilitarian. This is one symptom of the cultural decline of our Western tradition since the Eighteenth Century. The making of pots has persisted from earliest times to the present day through our ever changing world. Circumstances have at times obscured the essential truths of this art.
- Full Text:
The response of pure organic crystals to ionising radiations
- Authors: King, J W
- Date: 1953
- Subjects: Inorganic scintillators , Crystals
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5529 , http://hdl.handle.net/10962/d1012641 , Inorganic scintillators , Crystals
- Description: The introduction contains introductory remarks on scintillation counters together with a brief description of the exciton theory believed to be the means of primary energy migration within organic crystals. Part I contains a review of the data published on the reletive responses of different organic crystals and the attempted correlations of these results with the molecular structures of the different phosphors. From data which may be accepted as being both reliable and suitable for comparison it is concluded that theories involving correlations between phosphor efficiencies and molecular structures may be tested only if the efficiency data has (i) been extrapolated to give results for crystals of very small thickness and {ii) been obtained at very low temperatures. Part II contains accurate calculations based on the exciton theory proposed by Birks (1951 ) to account for the response of crystals to different types of ionising radiations. Satisfactory agreement is obta1ned with all the avalable experimental data in the literature. In part III an account is given of the response of organic crystals observed by the author for low-energy ⋉particles, and of the similar behaviour found by Taylor et al, (1951 ) for low-energy electrons. A possible extension of the theory described in part II, allowing for the escape of excitons through the crystal surface is given accounting for this behaviour. An exciton mean free path in anthracene, terphenyl and stilbene of about 3 - 7/u is obtained. Results were obtained with strong ⋉-particle sources which could not be explained. in terms ot normal response of the phosphor used. This effect was inventigatea as described in part IV, and it is shown that photons are produced in air, glass and quartz when these materials are irradiated by ⋉particles. This luminescence was probably responsible for the "scintillations" which Richards and Cole (1951) have ascribed to thin films of various materials. Problems requiring further investigation are indicated.
- Full Text:
- Authors: King, J W
- Date: 1953
- Subjects: Inorganic scintillators , Crystals
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5529 , http://hdl.handle.net/10962/d1012641 , Inorganic scintillators , Crystals
- Description: The introduction contains introductory remarks on scintillation counters together with a brief description of the exciton theory believed to be the means of primary energy migration within organic crystals. Part I contains a review of the data published on the reletive responses of different organic crystals and the attempted correlations of these results with the molecular structures of the different phosphors. From data which may be accepted as being both reliable and suitable for comparison it is concluded that theories involving correlations between phosphor efficiencies and molecular structures may be tested only if the efficiency data has (i) been extrapolated to give results for crystals of very small thickness and {ii) been obtained at very low temperatures. Part II contains accurate calculations based on the exciton theory proposed by Birks (1951 ) to account for the response of crystals to different types of ionising radiations. Satisfactory agreement is obta1ned with all the avalable experimental data in the literature. In part III an account is given of the response of organic crystals observed by the author for low-energy ⋉particles, and of the similar behaviour found by Taylor et al, (1951 ) for low-energy electrons. A possible extension of the theory described in part II, allowing for the escape of excitons through the crystal surface is given accounting for this behaviour. An exciton mean free path in anthracene, terphenyl and stilbene of about 3 - 7/u is obtained. Results were obtained with strong ⋉-particle sources which could not be explained. in terms ot normal response of the phosphor used. This effect was inventigatea as described in part IV, and it is shown that photons are produced in air, glass and quartz when these materials are irradiated by ⋉particles. This luminescence was probably responsible for the "scintillations" which Richards and Cole (1951) have ascribed to thin films of various materials. Problems requiring further investigation are indicated.
- Full Text:
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