Characterization and computer simulation of corn stover/coal blends for co-gasification in a downdraft gasifier
- Authors: Mabizela, Polycarp Sbusiso
- Date: 2014
- Language: English
- Type: Thesis , Masters , MSc (Physics)
- Identifier: vital:11600 , http://hdl.handle.net/10353/d1020203
- Description: The need for sustainable alternative energy technology is becoming more urgent as the demand for clean energy environment increases. For centuries, electricity in South Africa has been derived mostly from coal with results growing in multifold annually due to concerns about the impact of fossil fuel utilization related to emission of greenhouse gasses. It is practically impossible at the moment to replace coal with biomass resources because of the low energy value of biomass. However, the conversion of coal has experienced some challenges especially during its gasification which includes, but are not limited to a high reaction temperature exceeding 900°C which most gasifiers cannot achieve, and if achieved in most cases, combustion of the resulting syngas usually occur, leading to low conversion efficiency and the risk of reaching extremely high temperatures that may result in pressure build up and explosion may also occur. Therefore, this study sought to investigate the possibility of co-gasifying corn stover with coal with the ultimate aim establishing the best mixing ratio that would result in optimum co-gasification efficiency after computer simulation. Proximate and ultimate analysis, including energy values of corn stover and coal as well as their blends were undertaken and results showed significant differences between the two feedstocks and narrow range composition betwee their blends in terms of properties and energy value. Corn stover showed a higher fraction of volatile matter and lower ash content than coal, whereas those of their blends vary considerably in terms of physical properties. Differences in chemical composition also showed higher fraction of hydrogen and oxygen, and less carbon than coal while those of their blends vary according to the ratio of corn stover to coal and vice versa in the blends. The thermal stability of corn stover and coal as well as their blends were also established and the maximum temperature reached for thermal degradation of their blends was 900°C as depicted by TGA analysis. The SEM results revealed no changes in morphology of the pure samples of corn stover and coal which was due to the fact that a pre-treatment of the samples were not undertaken, whereas the blends showed significant changes in morphology as a result of blending. However, luminous and non-luminous features were noticed in both SEM images of the blends with the 10% coal/90% corn stover blend having higher percentages of luminosity as a result of higher quantities of coal in the blend. The energy density of the samples were also measured and found to be 16.1 MJ/kg and 22.8 MJ/kg for corn stover and coal respectively. Those of their blends varied from 16.9 to approximately 23.5 MJ/kg. These results were used to conduct computer simulation of the co-gasification process in order to establish the best blend that would result in maximum co-gasification efficiency. The blend 90% corn stover/10% coal was found to be the most suitable blend for co-gasification resulting in an efficiency of approximately 58% because its conversion was efficiently achieved at a temperature that is intermediate to that of coal and biomass independently. The simulation results were, however, compared with experimental data found in the literature and results showed only slight variation between them.
- Full Text:
- Authors: Mabizela, Polycarp Sbusiso
- Date: 2014
- Language: English
- Type: Thesis , Masters , MSc (Physics)
- Identifier: vital:11600 , http://hdl.handle.net/10353/d1020203
- Description: The need for sustainable alternative energy technology is becoming more urgent as the demand for clean energy environment increases. For centuries, electricity in South Africa has been derived mostly from coal with results growing in multifold annually due to concerns about the impact of fossil fuel utilization related to emission of greenhouse gasses. It is practically impossible at the moment to replace coal with biomass resources because of the low energy value of biomass. However, the conversion of coal has experienced some challenges especially during its gasification which includes, but are not limited to a high reaction temperature exceeding 900°C which most gasifiers cannot achieve, and if achieved in most cases, combustion of the resulting syngas usually occur, leading to low conversion efficiency and the risk of reaching extremely high temperatures that may result in pressure build up and explosion may also occur. Therefore, this study sought to investigate the possibility of co-gasifying corn stover with coal with the ultimate aim establishing the best mixing ratio that would result in optimum co-gasification efficiency after computer simulation. Proximate and ultimate analysis, including energy values of corn stover and coal as well as their blends were undertaken and results showed significant differences between the two feedstocks and narrow range composition betwee their blends in terms of properties and energy value. Corn stover showed a higher fraction of volatile matter and lower ash content than coal, whereas those of their blends vary considerably in terms of physical properties. Differences in chemical composition also showed higher fraction of hydrogen and oxygen, and less carbon than coal while those of their blends vary according to the ratio of corn stover to coal and vice versa in the blends. The thermal stability of corn stover and coal as well as their blends were also established and the maximum temperature reached for thermal degradation of their blends was 900°C as depicted by TGA analysis. The SEM results revealed no changes in morphology of the pure samples of corn stover and coal which was due to the fact that a pre-treatment of the samples were not undertaken, whereas the blends showed significant changes in morphology as a result of blending. However, luminous and non-luminous features were noticed in both SEM images of the blends with the 10% coal/90% corn stover blend having higher percentages of luminosity as a result of higher quantities of coal in the blend. The energy density of the samples were also measured and found to be 16.1 MJ/kg and 22.8 MJ/kg for corn stover and coal respectively. Those of their blends varied from 16.9 to approximately 23.5 MJ/kg. These results were used to conduct computer simulation of the co-gasification process in order to establish the best blend that would result in maximum co-gasification efficiency. The blend 90% corn stover/10% coal was found to be the most suitable blend for co-gasification resulting in an efficiency of approximately 58% because its conversion was efficiently achieved at a temperature that is intermediate to that of coal and biomass independently. The simulation results were, however, compared with experimental data found in the literature and results showed only slight variation between them.
- Full Text:
Heterosexual students’ attitudes towards gays and lesbians: an Eastern Cape University survey
- Authors: Barry, Hilde-May
- Date: 2014
- Language: English
- Type: Thesis , Masters , M Soc Sc (C Psy)
- Identifier: http://hdl.handle.net/10353/1009 , vital:26517
- Description: While South Africa stands apart from other countries as being more progressive in terms of gay and lesbian rights, attitudes towards this population continue to be intolerant. Attitudes shape people’s behaviour and in a university setting young students are vulnerable to discrimination. This is often a time when young people are still shaping their identities. An electronic survey comprising the Attitudes towards Lesbians and Gay Men Scale was administered to 401 students taking undergraduate psychology courses at the East London Campus of the University of Fort Hare, to assess their attitudes towards gays and lesbians. The survey measured their attitudes in terms of the biographical variables of gender, age, race, and religiosity, commitment to religious practice, urban or rural upbringing and nationality. The results of the research found that gender, race, religiosity, religious attendance and rural or urban upbringing do influence students’ attitudes significantly. However, age did not have an effect on attitudes towards gays and lesbians in the present study. The significance of the differences in attitudes in terms of nationality was not able to be tested due to the small sample size of foreign students. The findings of this study show that there are fairly consistent predictors of students’ attitudes concerning gays and lesbians. This information can help us to clarify areas to target for improvement in the campus climate for gay and lesbian communities.
- Full Text:
- Authors: Barry, Hilde-May
- Date: 2014
- Language: English
- Type: Thesis , Masters , M Soc Sc (C Psy)
- Identifier: http://hdl.handle.net/10353/1009 , vital:26517
- Description: While South Africa stands apart from other countries as being more progressive in terms of gay and lesbian rights, attitudes towards this population continue to be intolerant. Attitudes shape people’s behaviour and in a university setting young students are vulnerable to discrimination. This is often a time when young people are still shaping their identities. An electronic survey comprising the Attitudes towards Lesbians and Gay Men Scale was administered to 401 students taking undergraduate psychology courses at the East London Campus of the University of Fort Hare, to assess their attitudes towards gays and lesbians. The survey measured their attitudes in terms of the biographical variables of gender, age, race, and religiosity, commitment to religious practice, urban or rural upbringing and nationality. The results of the research found that gender, race, religiosity, religious attendance and rural or urban upbringing do influence students’ attitudes significantly. However, age did not have an effect on attitudes towards gays and lesbians in the present study. The significance of the differences in attitudes in terms of nationality was not able to be tested due to the small sample size of foreign students. The findings of this study show that there are fairly consistent predictors of students’ attitudes concerning gays and lesbians. This information can help us to clarify areas to target for improvement in the campus climate for gay and lesbian communities.
- Full Text:
Investigating the provision of nutritional support to critically ill hospitalised patients by registered nurses in East London public and private hospitals in the Eastern Cape
- Authors: Mooi, Nomaxabiso Mildred
- Date: 2014
- Subjects: Nutritional support , Critical illness , Critical Care units , Registered nurses
- Language: English
- Type: Thesis , Masters , MSc (Nursing Science)
- Identifier: vital:11910 , http://hdl.handle.net/10353/d1015533 , Nutritional support , Critical illness , Critical Care units , Registered nurses
- Description: Critical illness is typically associated with a catabolic stress state in which patients commonly demonstrate a systemic inflammatory response that brings about changes in their body systems. Changes in the body systems make the critically ill dependent on mechanical ventilation and inotropic support for longer periods in order to survive. However, this inflammatory response can be attenuated by the timely introduction of nutritional support to provide energy and nutrients to diminish catabolism and promote anabolism. The result could be a decrease in the morbidity and mortality rates, as well as the financial burden on the patients, institutions and the state. Since registered nurses initiate and utilise feeding protocols to achieve target goals, there is a strong need for nurse-initiated feeding protocols. These protocols should be coupled with a comprehensive nurse-directed nutritional educational intervention that will focus on their safe and effective implementation. This focus on nursing nutrition education represents a major shift away from traditional education which has focused on dietitians and physicians. Evidence suggests that incorporating guideline recommendations into nurse-initiated protocols for starting and advancing enteral feedings is an effective strategy to improve the delivery of nutritional support. The study was aimed at exploring the provision of nutritional support to critically ill hospitalised patients by registered nurses to identify and describe possible gaps in the practice, through determining the potential relationship between the provision of nutritional support and characteristics of its providers. A quantitative, descriptive correlational study was undertaken. Seventy registered nurses working in neonatal/paediatric and adult critical care units in two public and three private hospitals in East London in the Eastern Cape participated in the study. The sample also included public critical care students. The results showed that registered nurses in private hospitals have more knowledge about the importance of nutritional support than their public hospital counterparts and students. The mean score was on the question was 80.3% with the highest score of 91% which was for the private hospital nurses, followed by 77.2% for public and 71.4% for students. Again, the mean score for knowledge on timing of initiating nutritional support was 48%, the highest score being 69.4% for students followed by private hospital nurses with 49.6%. Close to 63% (n = 44) of these nurses were either unsure about the availability of nutritional protocols or clearly attested to their non-availability. This is seen as an issue of concern because a protocol is meant to be a standard document with which all members of the ICU should be familiar. It is meant to guide and facilitate the manner of working in the unit. While facilitation of maintenance of nutritional support to patients is the responsibility of registered nurses, according to Regulation 2598(1984) section 45 (1) (q) of the South African Nursing Council, 68% (n = 48) of the respondents felt that this was in the practising scope of doctors and dietitians. The study concluded that the nurses are knowledgeable about the importance of nutritional support but knowledge gaps have been identified as far as the timing of initiating nutritional support is concerned. Some attested to unavailability of standard guidelines that are tailored into protocols guiding the provision of nutritional support by registered nurses in the critical care units. Nutrition should be prioritised as an important therapy for improving the outcomes of critically ill patients. Nurses need to analyse its provision, identify barriers to nutritional strategies and engage in nutritional education to empower themselves regarding the practice. Most importantly, there is a need for nurse-initiated nutritional protocols that are tailored from the broad nutritional guidelines and aligned with the local context and ways of practising. Nutritional support should be included as a key component of the curriculum in academic programmes that specialise in critical care nursing.
- Full Text:
- Authors: Mooi, Nomaxabiso Mildred
- Date: 2014
- Subjects: Nutritional support , Critical illness , Critical Care units , Registered nurses
- Language: English
- Type: Thesis , Masters , MSc (Nursing Science)
- Identifier: vital:11910 , http://hdl.handle.net/10353/d1015533 , Nutritional support , Critical illness , Critical Care units , Registered nurses
- Description: Critical illness is typically associated with a catabolic stress state in which patients commonly demonstrate a systemic inflammatory response that brings about changes in their body systems. Changes in the body systems make the critically ill dependent on mechanical ventilation and inotropic support for longer periods in order to survive. However, this inflammatory response can be attenuated by the timely introduction of nutritional support to provide energy and nutrients to diminish catabolism and promote anabolism. The result could be a decrease in the morbidity and mortality rates, as well as the financial burden on the patients, institutions and the state. Since registered nurses initiate and utilise feeding protocols to achieve target goals, there is a strong need for nurse-initiated feeding protocols. These protocols should be coupled with a comprehensive nurse-directed nutritional educational intervention that will focus on their safe and effective implementation. This focus on nursing nutrition education represents a major shift away from traditional education which has focused on dietitians and physicians. Evidence suggests that incorporating guideline recommendations into nurse-initiated protocols for starting and advancing enteral feedings is an effective strategy to improve the delivery of nutritional support. The study was aimed at exploring the provision of nutritional support to critically ill hospitalised patients by registered nurses to identify and describe possible gaps in the practice, through determining the potential relationship between the provision of nutritional support and characteristics of its providers. A quantitative, descriptive correlational study was undertaken. Seventy registered nurses working in neonatal/paediatric and adult critical care units in two public and three private hospitals in East London in the Eastern Cape participated in the study. The sample also included public critical care students. The results showed that registered nurses in private hospitals have more knowledge about the importance of nutritional support than their public hospital counterparts and students. The mean score was on the question was 80.3% with the highest score of 91% which was for the private hospital nurses, followed by 77.2% for public and 71.4% for students. Again, the mean score for knowledge on timing of initiating nutritional support was 48%, the highest score being 69.4% for students followed by private hospital nurses with 49.6%. Close to 63% (n = 44) of these nurses were either unsure about the availability of nutritional protocols or clearly attested to their non-availability. This is seen as an issue of concern because a protocol is meant to be a standard document with which all members of the ICU should be familiar. It is meant to guide and facilitate the manner of working in the unit. While facilitation of maintenance of nutritional support to patients is the responsibility of registered nurses, according to Regulation 2598(1984) section 45 (1) (q) of the South African Nursing Council, 68% (n = 48) of the respondents felt that this was in the practising scope of doctors and dietitians. The study concluded that the nurses are knowledgeable about the importance of nutritional support but knowledge gaps have been identified as far as the timing of initiating nutritional support is concerned. Some attested to unavailability of standard guidelines that are tailored into protocols guiding the provision of nutritional support by registered nurses in the critical care units. Nutrition should be prioritised as an important therapy for improving the outcomes of critically ill patients. Nurses need to analyse its provision, identify barriers to nutritional strategies and engage in nutritional education to empower themselves regarding the practice. Most importantly, there is a need for nurse-initiated nutritional protocols that are tailored from the broad nutritional guidelines and aligned with the local context and ways of practising. Nutritional support should be included as a key component of the curriculum in academic programmes that specialise in critical care nursing.
- Full Text:
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