Life cycle sustainability assessment of next generation energy infrastructure in Africa: Is there a case for biohydrogen after biomethane?

The recovery of energy in the form of biomethane gas from inexpensive biodegradable organic wastes is starting to become a cornerstone of green economy investments. It is possible that such installations could serve as a precursor for the infrastructural development of a hydrogen economy, since biogas processes can be modified to produce hydrogen instead of methane. It is unclear whether such a change would improve or worsen the environmental, social, and economic performance of such waste-to-energy installations. Earlier studies show that the dark fermentation process for biohydrogen production faces several challenges such as low yield and slower production rate. Furthermore, it is unclear whether the biohydrogen production technology offers potential benefits in terms of ecological and socioeconomic sustainability. This study explores the usage of Life Cycle Sustainability Assessment (LCSA) to investigate next generation energy options to support green economies in Africa. LCSA has been advocated by the United Nations Environment Programme (UNEP) to consider the evaluation of all environmental, social and economic negative impacts and benefits in decision-making processes towards more sustainable products throughout their life cycle. This thesis uses LCSA for comparing biomethane versus biohydrogen produced from organic wastes in three settings: agro-industrial processing, represented by brewery wastewater; urban, represented by the organic fraction of municipal solid waste (OFMSW); and rural, represented by cattle manure. In each setting, two end-uses of both fuels are considered, viz. electricity generation (combined heat and power (CHP) systems vs. fuel cell (FC) systems), and as vehicle fuel (compressed natural gas (CNG) vehicles vs. fuel cell (FC) vehicles). According to published information on biogas yields of the substrates (i.e. brewery wastewater, OFMSW, and cattle manure), biomethane achieve a significantly higher energetic yield than biohydrogen estimated at 9.0, 10.5, and 9.7 MJ/kg of volatile solids (VS) for the case of biomethane, and at 4.8, 1.4, and 0.9 MJ/kg of VS in the case of biohydrogen, for the three substrates respectively. This difference in energetic yields significantly impacts on all further sustainability performance of the fuels. Nevertheless, an LCSA comparison was constructed, combining environmental and social life cycle assessment with a life cycle cost calculation to present the overall sustainability performance index of the results. The results show that for the urban setting (exemplified by OFMSW), the application of biomethane in CHP systems provides the highest sustainability performance index (SPI) value estimated at 1.90, while that of vehicle operations in CNG vehicles stands at 1.83. For biohydrogen, the recovery of energy from brewery wastewater in the agro-industrial setting (exemplified by brewery wastewater), the application of biohydrogen in the FC systems commands the SPI value of 1.75, but the vehicle operation in the FC vehicles records a much lower performance value of 0.90. The results clearly indicate that the biomethane technology for the electricity generation offers the most sustainable performance outcome when compared with the biohydrogen technology for the electricity generation which stands at 1.90 and 1.75, respectively. In the case of vehicles operations the application of biomethane in the CNG vehicles records much higher sustainability performance index value when compared to FC vehicles which stands at 1.83 and 0.90, respectively. In the agro-industrial settings the application of the biomethane in the electricity generation systems is equal that of the application of the biomethane in the vehicle operations in the CNG vehicles, which stand at 1.73. In the case of the urban settings the application of biomethane in the electricity generations provides higher sustainability performance index value when compared to the vehicle operations in the CNG vehicles which records the value of 1.90 and 1.83, respectively. In rural settings (exemplified by cattle manure) the application of biomethane produced from cattle manure in CHP systems records high SPI value of 1.75, but application in the CNG vehicles records the SPI value estimated at 1.68. The outcomes of the study thus show that the generation and use of biomethane in all selected settings promises a better sustainability performance, when compared to biohydrogen. Agro-industrial settings, in particular, seem to be very well suited for biohydrogen production, and there is no strong case for the application of biohydrogen technology in both the urban and rural settings. It is observed that the life cycle cost performance is significantly influenced by the application of the fuel (i.e. either in electricity generation, or as fuel for vehicles), and not only by the type of technology implemented (i.e. anaerobic digestion vs. dark fermentation process). Clearly, decision making for implementation of a particular technology requires a sound decision on the demand of a particular fuel type, end application of the fuel and also the type of the technology implemented. It has been reported that the energetic efficiencies in fuel cells for electrical energy generation has reached the efficiency of approximately 80%. The results of this study demonstrate that biohydrogen application for electricity generation seems to be promising for application in agro-industrial settings. This setting has access to skilled technicians required for the operating of the biohydrogen production technology, and also the economic power for the implementation of the biohydrogen technology. Often the implementation of the biomethane technology in the agro-industrial settings is to advance economic savings that result from the installations of the biogas digester. Thus, the private sector can either directly or indirectly play a crucial role in the research and development for the next energy generation infrastructural development. The social aspects need to be considered when analysing the potential role of different energy technologies for sustainable development. Actually, people are accustomed to infrastructural development of biogas installation in rural areas when compared to the biohydrogen technology. The social performance in such settings is faced with serious challenges regarding the level of education among the people and availability of human capacity in terms of skill development for the implementation of the proper infrastructural development. In rural areas, there is a need to effectively pay attention to various stakeholders. It has been reported that in certain instances the energy generation technology can come to a halt if proper stakeholders and community leaders are not well informed about the plan to implement new energy generation technology. This thesis thus demonstrates how UNEP’s call to consider environmental, social and economic dimensions of new developments can be interpreted, with a special focus on technological advancement in energy production systems. The energy sector in Africa faces enormous twin challenges of making a leading development contribution whilst respecting environmental sustainability imperatives. This thesis provides realistic solutions and advice for policy development of implementation of renewable technological options in three types of African settings. In respect to the development of the methodological approach for assessment of energy production systems, this study specifically contributed through developing a stakeholder analysis. The stakeholder analysis presents the framework for mapping of relevant impact indicators across the three dimension of sustainability analysis, for the production of gaseous energy carriers from organic wastes. The approach shows how different participating parties, such as government, companies primarily in the energy sector, end users (domestic users), and non-governmental organizations (NGOs) can collaborate and clearly understood impacts in the three dimension of sustainability. Furthermore, this developed stakeholder analysis within the context of LCSA has a role to play in the policy development by creating awareness between government, energy users and energy companies during energy technological innovations. The stakeholder analysis developed in this study was shown to help determine the social indicators within the context of LCSA. In summary, while hydrogen may soon be applied as an energy carrier in practice, this thesis shows that as long as biohydrogen yields remain much lower than biomethane yields, there is no strong case for admitting biohydrogen technology in both urban and rural settings. At the moment it remains possible that biomethane infrastructural development could serve as a precursor for the infrastructural development for the biohydrogen technology in the agro-industrial settings

Detecting HIV associated neurocognitive disorders (HAND) using neurocognitive assessment test in Uganda

A research report submitted to the Faculty of Health Sciences, University of Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Epidemiology. August, 2017.Background: HIV associated neurocognitive disorders (HAND), are a well-established consequence of HIV infection yet there is a lack of normative data required for diagnosis in Sub-Saharan Africa. Screening tools such as the International HIV dementia scale (IHDS) that are routinely used in the Sub-Saharan African region have questionable validity. This study investigates the use of the neuropsychological test battery in the detection of HAND in the absence of normative data. Further, the construct validity of the IHDS in the detection of HAND in the Ugandan context is examined. Methods Secondary data from a longitudinal Mental Health study carried out in Uganda were analysed. Information from a total of 1121 patients who underwent neuropsychological assessment in the main study qualified for the present study. A descriptive analysis of the neuropsychological performance of the study participants was conducted. To assess the relationship between demographic factors and the neurocognitive test scores of the neuropsychological test battery, multiple linear regression models were fitted. To determine how well the neuropsychological test battery predicted the IHDS score, a receiver-operating curve (ROC) analysis was conducted. The construct validity of the IHDS in detecting HAND in the Ugandan population was then assessed using ROC analysis and published normative data. Results The total study population was 1,121 participants, with the majority being female (66.3%) while almost 62% had only primary school education. The mean age of the study participants was 35.0±9.3 years. Using the IHDS, 73.3% of the HIV infected patients were identified to be at risk of developing HIV associated dementia (HAD). Using the Frascati criteria and published normative data, only 9.1% of the HIV infected patients had HAND. Ageing, being female, having a lower socio-economic score and having lower levels of education were identified as predictors for poor neurocognitive performance. Poor performance in the neurocognitive measures to assess gross and fine motor function was directly proportional to poor performance in the IHDS (score ≥10 points). Better performance in the neurocognitive measures to assess verbal leaning/working memory and attention/working memory was directly proportional to poor performance in the IHDS (score ≥10 points). The neurocognitive tests discriminated modestly between patients at risk of developing HAD and those that were not at risk of developing HAD (sensitivity=64.62%; specificity=66.67%). At the recommended cut-off score of 10 points, the IHDS had poor ability to identify patients with HAND (sensitivity=34.54%) and a high ability to identify patients without HAND (specificity=90.74%). At a cut-off point of 7 points, the IHDS discriminated modestly between patients with HAND and those without (sensitivity=65.66%; specificity=58.52%). Conclusion The neuropsychological test battery used in the present study discriminated modestly among HIV patients at risk of developing HIV associated dementia and those that were not at risk of developing dementia. In the Ugandan population, the construct validity of the IHDS in the diagnosis of HAND was poor. Further work is required to produce an algorithm to detect HAND in the absence of normative data. This includes an inclusion of important clinical biomarkers, exploration of further demographic confounders as well strengthening of the HAND diagnostic criteria using the neuropsychological test battery.LG201

The representation of the nature of science in South African Grade 12 Life Sciences textbooks

Abstract: This study examined the representation of the nature of science in South African Grade 12 Life Sciences textbooks using a conceptual framework developed by Chiappetta, Fillman and Sethna (1991a). The study investigated the extent to which South African Grade 12 Life Sciences textbooks exhibit the themes associated with the nature of science as an essential tenet in science education. The investigation primarily focused on the identification of the differences and commonalities exhibited by Grade 12 Life Sciences textbooks in terms of the coverage of the themes associated with the nature of science. These textbooks were essentially instructional resources that formed an integral part of the enactment of the National Curriculum Statement and the Curriculum and Assessment Policy Statement promulgated by the Department of Basic Education in South Africa. The investigation revealed a dismal depiction of the nature of science themes across the selected Grade 12 Life Sciences textbooks analysed. In particular, “Science as a body of knowledge” was given substantial coverage as compared to other concomitant themes. While considerable emphasis is placed on the significance of inquiry-based learning as a contemporary pedagogic approach, limited coverage was, however, given to “The investigative nature of science” and “Science as a way of thinking” as relevant themes required for meaningful enactment of inquiry-based learning. Science and technology play a pivotal role towards the fulfilment of societal and economic needs. Yet, the “Interaction among science, technology and society” was afforded limited coverage across the selected textbooks analysed. Implications for meaningful curriculum reform are discussed.M.Ed. (Science Education

The synthesis and photophysical properties of water soluble tetrasulfonated, octacarboxylated and quaternised 2,(3)-tetra-(2 pyridiloxy) Ga phthalocyanines

The photophysical behaviour of chlorogallium 2,(3)-tetra-(2 pyridiloxy) phthalocyanine (ClGaT-2-PyPc) and its quaternised derivative were compared with that of the water soluble anionic tetrasulfonated gallium phthalocyanine ((OH)GaTSPc) and hydoxy gallium octacarboxy phthalocyanine ((OH)GaOCPc). Although both the quaternised compound and the tetrasulfonated gallium phthalocyanine aggregated in aq. solution at pH 11, resulting in low fluorescence and triplet yields, the presence of the surfactant Cremophore EL improved yields. Triplet quantum yields ranged from 0.52 to 0.70 and fluorescence quantum yields ranged from <0.01 to 0.21. The nature of substituent (sulfonate, carboxy and pyridiloxy) did not influence photophysical properties. Chlorogallium 2,(3)-tetra-(2 pyridiloxy) phthalocyanine and its quaternised derivative displayed longer triplet lifetime than both the tetrasulfonated gallium phthalocyanine ((OH)GaTSPc) and hydroxy gallium octacarboxy phthalocyanine in DMSO and in aq. media in both the presence and absence of surfactant

Effects of nicotine on content of corticotropin releasing factor (CRF) in rat amygdala, hypothalamus and brain stem

Effects of 1.0 mg/kg and 0.4 mg/kg intraperitoneal nicotine on hypothalamic and extra hypothalamic levels of corticotropin releasing factor (CRF) were examined in 104 rats. CRF, a 41-amino acid peptide involved in responses to stress, fear and anxiety, influences the same neurotransmitter systems as nicotine, a psychoactive component of tobacco. Radioimmunoassays revealed that in macro-dissected hypothalami, 15 minutes treatment with 1.0 mg/kg nicotine significantly increased CRF content compared to no treatment. The 1.0 mg/kg dose did not elicit effects in macro-dissected amygdala and brain stem. With 0.4 mg/kg nicotine, no significant effects were observed in micro-dissected hypothalamic paraventricular nucleus, amygdaloid and brain stem nuclei. As expected, plasma corticosterone levels were significantly increased with both doses of nicotine. Overall, no clear cut effects of nicotine on CRF were observed. Micro-dissection studies on specific nuclei using varying doses and time points would help elucidate interactions of nicotine with CRF systems

Report on the Human Sciences Research Council (HSRC) 2012 Conference — The Re-emergence of Astronomy in Africa — A Transdisciplinary Interface of Knowledge Systems

Report on the Human Sciences Research Council (HSRC) 2012 Conference — The Re-emergence of Astronomy in Africa — A Transdisciplinary Interface of Knowledge System

Dentinogenic Ghost Cell Tumour, a rare case of an African young female patient: Review of literature and report of a case

Dentinogenic ghost cell tumour (DGCT) is a very rare aggressive benign odontogenic tumour with high recurrence rate and a potential to transform into malignancy. It can render facial disfigurement. The tumour is most frequently encountered in males than females with a ratio of 2:1. The peak incidence is in patients aged 40 - 60 years and the posterior mandible is slightly more affected than the maxilla. Segmental resection is a recommended surgical treatment and long-term postsurgical follow up is essential. This paper discusses a case of a 20-year-old African female patient who was diagnosed with a DGCT

Aggressive odontogenic myxoma of the maxilla in a 9-year-old child. Report of a case and literature review

Odontogenic myxoma is a rare, locally aggressive benign tumour of odontogenic ectomesenchyme origin. The tumour may cause signifi cant facial disfi gurement and has a negative psychological impact on a child. Odontogenic myxoma has predilection for females in the second and third decades of life. The mandibular molar region is the most frequently affected site. It is imperative to detect the tumour early to avoid radical surgery and reduce local recurrences. This case study reports a case of a 9-year-old female patient who presented with an expansile tumour that affected the entire left maxilla, perforated into the left maxillary sinus and completely occluded the sinus

Low symmetry metallophthalocyanines and their nanoparticle conjugates for photodynamic antimicrobial chemotherapy

This thesis reports on the syntheses of novel low symmetrically substituted Zn, Sn, Ge and Ti MPc complexes containing a single carboxylic or cysteinyl group available for attachments to MNPs. The complexes were extensively characterized by various techniques to ensure their purity. Various metallic nanoparticles consisting of silver (AgNPs), gold (AuNPs) as well as quantum dots (QDs) were successfully prepared and conjugated to the low symmetry phthalocyanine complexes. The conjugates were successfully characterized using many techniques. The Q-band maxima of the MPcs were observed at completely different wavelength regions depending on the nature of the substituents and the central metal used. Blue shifting of the Q band in the absorption spectra was observed for the complexes in the presence of AuNPs, while aggregation was observed in the presence of quantum dots. The complexes were successfully electrospun into polymer fibers for the antimicrobial inhibition of bacteria. The photophysical and photochemical properties of these complexes were extensively investigated. Higher triplet and singlet oxygen quantum yields were achieved for the Ge Pc complexes, with all the complexes giving reasonable singlet oxygen quantum yields. An enhancement in triplet and singlet oxygen quantum yields was observed for all the complexes in the presence of metal nanoparticles. However, the singlet oxygen quantum yields decreased for all the complexes when incorporated into electrospun fibers. The antimicrobial behaviour of the complexes was investigated against Bacillus Subtilis and Staphylococcus Aureus in solution and in the fiber matrix. High antimicrobial inhibitions were observed for the Ge complexes followed by the ZnPc derivatives. All the low symmetry ZnPc derivatives were conjugated to AgNPs and their antimicrobial behaviour was compared to their symmetrical counterparts. The best antimicrobial inhibition behaviour was observed for the low symmetry Pcs when compared to their symmetrical counterparts. In the absence and in the presence of AgNPs, axially ligated SiPc also showed better antimicrobial activity when it was compared to the unsubstituted ZnPc complex