Effects of TiO2 and CS supports on hydrogen spillover in Co and Ru supported catalysts

School of Chemical and Metallurgical Engineering, Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, South Africa 22nd of February, 2018Hydrogen spillover is the surface migration of activated hydrogen atoms from a metal catalyst particle, on which they are generated, onto the catalyst support. A lot of research work has been done on hydrogen spillover since its discovery in 1964, and its incidence on reducible supports such as titanium oxide is established, yet questions remain about the role of the support in hydrogen spillover in heterogeneous catalysis. The aim of this research was to investigate the role of a support in hydrogen spillover, using cobalt and ruthenium supported on TiO2 and CS catalysts. These two catalysts were prepared by deposition precipitation-urea, incipient wetness impregnation and polyol methods and characterized using TGA, TEM, BET, XRD and Raman spectroscopic analysis. The Fischer-Tropsch evaluation of the catalysts was done in a fixed bed reactor and the products were analyzed on offline gas chromatographs. The results show a significant shift to lower reduction temperatures for the CoO to Co peak for the physical mixture of Co/TiO2 and Ru/TiO2. However, when Co/TiO2 and Ru/TiO2 catalysts were packed in a bed system separated by different amounts of TiO2, no significant change was observed compared to the “hybrid” catalyst. The separation distance between the two catalysts had no effect in the reduction temperature. The improved reducibility of CoO to Co was attributed to the dissociation of H2 on the Ru, which made the Ru/TiO2 catalyst the donor phase causing the hydrogen to spillover to the acceptor phase which is the Co/TiO2. The same finding was observed for the Ru and Co catalysts supported on the carbon spheres where the CoO to Co peak was shifted to lower reduction temperature compared to the monometallic Co/CS catalyst. The reducibility was attributed to the presence of Ru. For the Co and Ru catalysts supported on carbon spheres the physically mixed Co/CS and Ru/CS catalysts resulted in the increase of C5+ selectivities compared to the monometallic catalysts of Co catalysts. Microwave irradiation had a positive effect on the dispersion and surface area on the catalyst prepared using the polyol and incipient wetness methods.MT 201

Households’ Willingness to Pay for Improved Water Services: A Case of Semi-Urban Households in the Lubombo and Lowveld Regions of Swaziland

Management of water resources in an equitable manner by water managers has proved to be a demanding task. Therefore, evaluating domestic water demand behaviours produces an underlying basis for water managers to sustainably and efficiently meet the ever increasing demand for water. Using survey data collected from 314 households in the Lowveld and Lubombo regions of Swaziland, this paper uses the Contingent Valuation Method (CVM) to determine households’ willingness to pay (WTP) for improved water services. In estimating the parametric mean WTP and its determinants, the paper uses both the bivariate probit model and univariate probit model, respectively. The results show that 67% of the households were willing to pay the initial bid for improved water services. The mean WTP for a 20 litre of water was estimated at E0.47[1]. Probit model results show that household income, education, gender, distance and owning a backyard garden positively influence household WTP. However, age, water quality and the initial bid offered deter households WTP for improved water services. This suggests that socioeconomic factors should be considered when setting domestic water tariffs and designing strategies for improved water supply services. Keywords: Willingness to Pay (WTP), Contingent Valuation Method (CVM), Swaziland [1] 1 USD = E13.5 Emalangen

Universities trailing behind: Unquestioned epistemological foundations constraining the transition to online instructional delivery and learning

Universities across South Africa have positioned learning management systems (LMS) as central to remote teaching and learning in response to COVID-19. This fundamentally challenges traditional teaching and learning practices where lecturers typically have close personal contact with students. Our argument is underpinned by critical discourse analysis and social constructivist pedagogy to gain deeper insights into the dimensions of LMS pedagogical affordances and the notion of equitable access to tertiary education in the midst of COVID-19 and the subsequent education and economic depression. Conducting a social constructivist pedagogy inspired analytical argumentative evaluation, we interrogate how digital technologies and platforms challenge the status quo and then argue on the systemic deficits of placing LMS at the centre of the transition in the hope of automatically cultivating an equitable learning environment to enable ubiquitous learning. Our analysis highlights potential contradictions in universities’ reliance on lecturers’ ingenuity without developing enabling structures supporting digital pedagogies at grassroots. This is to ensure inclusivity and avoid creating systemic inequalities that affect individual students’ experiences

Experiences of Cooperating Teachers on Teaching Practice Supervision in Eswatini, Swaziland

Cooperating teachers (CTs) are key participants in ensuring a valuable experience for the student teacher (ST) during teaching practice. Surprisingly, their voices largely remain absent in the extant literature. Thus, the purpose of the study was to investigate the experiences of CTs during teaching practice supervision in Eswatini. A descriptive research design using a census of 46 CTs for student teachers (STs) who did teaching practice in the 2015/16 academic year of the University of Eswatini in the Department of Agricultural Education was used. A selfadministered questionnaire was used for collecting data. A five-point numerical scale and sixpoint Likert-type rating scale were used to measure the variables. Three lecturers from the Department of Agricultural Education and Extension and two agriculture teachers established content and face validity for the questionnaire. Inter-item reliability from a pilot study was .78. Findings of the study revealed that CTs were supported by the University through the supervisors and Teaching Practice Handbook. The CTs noted that establishing rapport with the STs was essential and head teachers needed to visit the STs in the respective classes they teach. STs were good in developing, organizing and using instructional materials but had challenges in disciplining learners. The study recommended that CTs should be provided with trainings and incentives so that they can effectively discharge their duties during teaching practice

Review: Use of EEG on Measuring Stress Levels When Painting and Programming

For years, brain activity, stress level during programming and painting have been analyzed separately. As the world gets more digital and human life gets more dependent on technology, it has become more important to analyse the relationship between programming, software developers’ brain activity, creative practices (i.e painting) and stress level. In this paper, we present the results of a systematic literature review whereby the research questions are centred around analysing the relationship between stress levels and brain activity when a person is painting or writing a piece of software. The search for relevant studies was done on google scholar and IEEE Xplore. The results of our review show that: (1) EEG can be used to accurately measure stress levels, (2) there is limited research in the analysis of stress level pattern of the stress level when people paint depending on different situations and styles of painting. In light of the systematic literature review result, using EEG we plan to conduct experiments to measure the stress level when a person is painting a picture or programming

The use of hypercapnic challenge blood oxygen level dependent (BOLD) MRI for the investigation of childhood steno-occlusive arteriopathy

BACKGROUND: In childhood, cerebral arteriopathy causes cerebral ischaemia and infarction via two related mechanisms. The first, thrombotic vaso-occlusive stroke is the more typical mechanism of stroke in childhood. The second mechanism of infarction related to arteriopathy and not seen in other forms of ischaemic stroke is that of chronic hypoperfusion of the brain. The infarcts in this case are typically located in watershed zones and can accumulate gradually over time. Moyamoya is the prototypic arteriopathy representing the hypoperfusion injury. It is characterized by chronic progressive narrowing of the distal internal carotid, proximal middle cerebral and anterior cerebral arteries; chronic low flow infarction with accumulating ‘string of pearls’ in the white matter (Fig 1). It is this chronic hypoperfusion of the brain that is the subject of my PhD thesis. Cerebrovascular reactivity is a marker of cerebrovascular reserve and has been shown to be a biomarker of ischaemic risk in adults. OBJECTIVES: The primary objectives were to, in a group of children with moyamoya: 1) Validate the use of a qualitative measure of cerebrovascular reactivity as a biomarker of ischaemic risk, namely, hypercapnic challenge BOLD MRI CVR (hBOLD CVR) via two methods: a) breath-holding and b) induced hypercapnia during general anaesthesia as reliable and repeatable for use in the paediatric population 2) Assess the utility of qualitative assessment of cerebrovascular reactivity using hBOLD CVR as a tool for the identification of the risk of ischaemia in children with arteriopathy Method Hypercapnic challenge hBOLD CVR studies were obtained in children with steno-occlusive arteriopathy prospectively enrolled in The Hospital for Sick Children Stroke Registry. Semi-quantitative methods of measuring CVR were devised and used for the purpose of analysis. hBOLD CVR studies were analysed for reliability and reproducibility of the method of analysis. Clinical and radiologic data were collected and hBOLD CVR findings described for all children enrolled. Exploratory analysis of hBOLD CVR as a potential biomarker of ischaemic risk in the paediatric population were conducted. In particular association of hBOLD CVR with clinical symptomatology; parenchymal and vascular indicators of arteriopathy; neuropsychological outcome and cortical thickness were examined. Results Forty seven children (37 Bilateral or unilateral Moyamoya arteriopathy, 6 Unilateral Non-moyamoya arteriopathy [Transient Cerebral Arteriopathy] and 4 Bilateral Non-moyamoya arteriopathy [2 PHACE(S), 1 Takayasu arteritis, 1 Sickle Cell Disease]) were enrolled and had hBOLD CVR studies. The mean age of diagnosis of arteriopathy across all groups was 8.1 years (SD 4.2) (range 7 months - 18 years). Clinical and radiographic features differed across arteriopathy groups. Most presented with acute stroke, however, among children with NF1-MM most (almost 50%) were asymptomatic and diagnosed on screening MRIs. Infarction patterns differed, with deep watershed infarction being the typical pattern in the moyamoya group in contrast to thrombotic vaso-occlusive infarction pattern in the Non-moyamoya groups. Qualitative hBOLD CVR abnormalities were concordant with moyamoya laterality, and in unilateral moyamoya demonstrated tissue level microvascular dysfunction in the contralateral unaffected hemisphere. Qualitative hBOLD CVR abnormalities demonstrated concordance with clinically important manifestations of ischaemia including stroke, transient ischaemic attacks, cortical thinning and IQ. There was a lack of concordance with indices of executive function. In addition the moderate to severe steno-occlusive arteriopathy seen in the children with Transient Cerebral Arteriopathy was not associated with abnormality of hBOLD CVR. Conclusion The thesis studies demonstrated that qualitative assessment of hBOLD CVR using breath-hold or general anaesthetic is feasible, reproducible and reliable in paediatric population. The utility of hBOLD CVR as a measure of tissue level microvascular dysfunction and thus a biomarker of ischaemic risk was demonstrated. However, larger longitudinal studies are required to characterize this further

THE IMPACT OF MACROECONOMIC POLICIES ON AGRICULTURE IN SWAZILAND: AN EMPIRICAL ANALYSIS (1980-2012)

Policymakers in Swaziland view agriculture as an engine to foster economic growth, reduce poverty and eradicate inequality among the populace when the right policies are formulated and implemented within their rightful institutional framework. This study is an empirical investigation of the effect of macroeconomic policies on the agricultural sector in Swaziland using annual time-series data for the period 1980 to 2012. The study used the bound test approach to cointegration to analyse the data. The cointegration results revealed that there was long run relationship amongst the variables of agriculture GDP and export. The results also revealed that real money supply, real exchange rate, real GDP, and real government expenditure had a significant long run impact on agriculture GDP with elasticity coefficients of 0.07, 0.24, 0.88 and -0.3 respectively, while short run coefficients were -0.002,0.23,-0,94 and -0.4 respectively.  In the case of agriculture exports, the results further revealed that real money supply, real government expenditure, discount rate, real exchange rate and real GDP had a significant impact on the sector`s exports with long run elasticity coefficients of 0.13,-0.32,-0.01,0.5 and 2.53 respectively, while short run elasticities were 0.06,0.35,0.01,0.46 and -1.34 respectively.The Central Bank of Swaziland needs to adopt policies aimed at providing affordable credit to agriculture. In terms of the low response of the agricultural sector to macro-policy variables the study recommends that policymakers should intensify the promotion of finished or processed agriculture exports and create a disincentive to imports. Keywords: Agriculture, exports, prices, macroeconomic policy, cointegration, autoregressive distributed lag model (ARDL), Swaziland

CHARACTERISATION OF MULTIVARIATE TRAITS IN SWAZI INDIGENOUS GOATS

Swazi goats from two different regions in Swaziland kept in communal systems were characterised based on phenotypic measurements. Objective measurements for 200 goats included body weight (BW), abdominal circumference (AC), body length (BL), chest circumference (CC), face length (FL), neck circumference (NC), neck length (NL), rump height (RH) and height at withers (HW), while qualitative traits included coat colour, coat texture and presence or absence of horns. Seven coat colours were observed across both regions. Goats with straight coat texture (82%), short hair length (68%) and with horns (84%) were predominantly more. Goats in Manzini region had the lower BW, AC, BL and CC (51.77±1.32, 61.77±1.32, 62.49±0.66, 57.96±1.18) than Shiselweni goats (53.09±1.01, 71.09±1.00, 73.67±0.94, 53.83±0.90). The study provided a reference for phenotypic and genetic diversity for Swazi goats useful for designing genetic strategies for improved production, food security and sustainable utilisation

Inpatient case fatality rates improvements in children under 5: Diarrhoeal disease, pneumonia and severe acute malnutrition

Data on the number of admissions and deaths in children aged under 5 years from diarrhoea, pneumonia and severe acute malnutrition are routinely collected through the District Health Information System. These data, and the associated case fatality rates, are available for all public sector hospitals in South Africa (SA), and can be compared over time, as well as across different settings. This article presents these data for the period 2011/12 - 2016/17. It reflects on the remarkable improvements in these case fatality rates, and the likely reasons for their declines across all provinces. The article concludes by identifying the actions that need to be taken to ensure that SA achieves the Sustainable Development Goal aim of ending preventable child deaths by 2030