1834 research outputs found
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Optimisation of a mini horizontal axis wind turbine to increase energy yield during short duration wind variations
No full textThe typical methodology for analytically designing a wind turbine blade is by means of blade element momentum (BEM) theory, whereby the aerofoil angle of attack is optimized to achieve a maximum lift-to-drag ratio. This research aims to show that an alternative optimisation methodology could yield better results, especially in gusty and turbulent wind conditions. This alternative method looks at increasing the aerofoil Reynolds number by increasing the aerofoil chord length. The increased Reynolds number generally increases the e_ectiveness of the aerofoil which would result in a higher or similar lift-to-drag ratio (even at the decreased angle of attacked require to maintain the turbine thrust coe_cient). The bene_t of this design is a atter power curve which causes the turbine to be less sensitive to uctuating winds. Also, the turbine has more torque at startup, allowing for operatation in lower wind speeds. This research is assumed to only be applicable to small wind turbines which operated in a low Reynolds number regime (<500 000), where Reynolds number manipulation is most advantageous.National Research Foundatio
Appropriate integration of workers with physical limitations into a manual workplace - development of an assessment tool
No full textPeople with physical limitations can contribute significantly to society and the economy, however, barriers to full and effective participation in the labour market often hinder decent employment. In light of this, placement decisions of impaired workers should be based on detailed information of the nature of the jobs available, as well as individual capabilities of the worker. An ergonomics approach to design attempts to achieve an appropriate balance between the capabilities of the worker and the requirements of the task and uses this balance to improve productivity and encourage physical and mental well-being, job satisfaction and safety. A specific analysis tool which can be applied to various workplaces and jobs, and provide information for decisions regarding placement of physically limited workers, will help to increase the percentage of correct placement in an appropriate workplace, resulting in optimum productivity and worker safety. Methods: An assessment tool which allows matching of job requirements and worker capabilities was developed based on a theoretical framework from Mattison and Goebel (2007), as well as principles defined by Almgren and Schaurig (2012) and Demura and Nakada (2010). The tool assesses range of motion, force and time components of the physical requirements of different tasks involved in the job, as well as movement capabilities and limitations of the worker. The tool was pilot tested in a case study with an above the knee amputee working at a research facility. Results: The tool successfully provided information regarding the matching of the work to the identified job. The output of the tool highlighted two tasks which would place the worker at risk due to physical requirements of the tasks being greater than movement capabilities of the worker. These tasks need to be further investigated to determine if accommodations can be made to assist the worker in safely performing the task, or if the job is not suitable for the worker. Conclusions: The tool developed was useful in providing information to inform appropriate placement of the physically limited worker. Further research needs to be done to validate and determine reliability of the tool.National Research Foundatio
Lurking or listening? An ethnographic study of online and offline student political participation through the #MustFall protests at Rhodes University
No full textThe way media is created and consumed plays an important role in political participation as it provides information, guides thinking and allows citizens to make informed political choices. It can also interrogate the status quo and challenge existing systems or power relations. This thesis discusses the use of social media by Rhodes University students in the context of the 2015 #RhodesMustFall and #FeesMustFall protests in South Africa. This thesis interrogates the concept of slacktivism, a term used to describe online or digital activism which is considered to be less active and not as effective as physical activism. Furthermore, the thesis acknowledges that even when digital political participation is recognised, the emphasis and value is placed on those who speak and create content. The thesis examines the notion of participation and what counts as active citizenship. In particular, the majority of social media users who merely lurk and never contribute to content creation or online discussions are further investigated. The qualitative methodological approach used for this thesis involved three parts which looked at student activity on Facebook, student engagement offline, and how students made sense of their online and offline involvement. Firstly, a cyberethnographic investigation was done in order to understand the cyber world in which students are present. Thereafter, a participant observation was carried out to immerse myself in the offline spaces that students engaged in politically, to get a better sense of how their online presence influenced or supplemented their offline activity. Finally, individual interviews were carried out with lurkers to determine why they did not participate in traditional ways, both online and offline. The findings suggest that lurkers are in fact doing more than just being passively present. The high levels of attention paid to content posted by others on social media, as well as the way that the content influences their offline lives suggest that the choice to lurk is far more active than assumed. Students are consciously deciding to lurk for a multitude of reasons, one of which is for the opportunity to learn. Social media is a fast developing; increasingly used form of communication and how political communication across social media platforms is framed affects what we consider to be active engagement. By using theories of listening and emotion talk, the thesis provides new ways of understanding lurking by Rhodes University students on social media, which in turn can lead to better listening, better understanding and greater political participation.National Research Foundatio
Solubility and dissolution testing of selected sulfadoxine/pyrimethamine mixtures
No full textAlthough malaria is an age old disease it continues to plague mankind especially in the African regions. Pregnant women are more likely to be infected with malaria due to the hormonal changes with more severe symptoms and outcomes.
Intermittent preventive therapy with sulfadoxine (S) and pyrimethamine (P) are considered to be an effective way of preventing malaria in pregnant women; but the increase of the resistance of the malaria parasite to sulfadoxine and pyrimethamine is still a major concern. Some of the possible causes of resistance include the poor solubility and dissolution rate of both drugs. Addressing these problems might be a positive stepping stone towards combating malaria resistance in the future.
The focus of this study was to determine the solubility and dissolution properties and possible chemical interactions in the powder mixtures compared to the single components. Distilled water, phosphate buffer (pH 6.8) and 0.1 N HCl were used as media for solubility and dissolution testing.
The results of the SP combinations emphasised that sulfadoxine and pyrimethamine is more soluble in distilled water and PBS; but when in combination both of these actives’ solubility decreases in 0.1 N HCl. In contrast with the solubility results, the best results obtained during dissolution testing were in 0.1 N HCl. For each dissolution medium, only some of the SP combinations correspond with the USP requirements (60% or higher dissolution in 30 minutes) for each tablet.
Differential scanning calorimetry (DSC) and x-ray powder diffraction (XRPD) were used to establish if interactions occur in the powder mixtures. The DSC results showed that during heating of certain SP combination ratios, shifting of melting point and even melting point depression occurs. This may indicate the possibility of a eutectic mixture being formed. With a percentage pyrimethamine of 55% (w/w) or higher in the mixture, two distinguishable melting endotherms were visible. XRPD results indicated that during exposure of SP combinations to distilled water, no other solid-state forms such as co-crystals of sulfadoxine and pyrimethamine formed.
To conclude, there is definitely an increase in the solubility and dissolution rate of sulfadoxine and pyrimethamine when in combination. The significance and origin of the increased solubility requires further investigation. The possibility of a eutectic mixture being formed also warrants further investigation.National Research Foundatio
The typical and connotative character of Xeinoi situations across the apologue: Three studies in repetition
No full textThis dissertation engages in a close reading and analysis of the Apologue of Homer's Odyssey; specifically, I am concerned with characterizing the nature of xeinoi situations or interactions in these books - that is, the relationship between the Ithacan travellers and the various inhabitants whom they encounter in these four books. There is a significant amount of scholarship on the nature of these encounters in the Apologue, and as my first chapter explores, many of these are often hinged upon certain polarities: hospitality versus inhospitality, civilized versus savage, masculine versus feminine. My study is greatly indebted to these; however, this dissertation explores new avenues of interpreting these encounters. I have adopted an approach to the Odyssey, which is based upon the importance of repetitions and their connotations, what has been termed 'traditional referentiality'. The Homeric poems are defined by an aesthetic of repetition: certain 'units' (which may be isolated words, phrases, actions, scenes, etc.) are given prominence in the narrative through their frequency; when these units are examined with respect to their contexts, the particular units gain associative or 'connotative' meaning from their implementation. In my second, third, and fourth chapters, I explore how the xeinoi situations in the Apologue are pervaded by certain typical units - namely, (i) mountains, (ii) acts of eating, and (iii) acts of trickery - and then, importantly, how these units garner connotative senses of, respectively, (i) isolation, (ii) danger, and (iii) success, which characterize the relationships in these four books. While some of these typical units have received scholarly treatment in the Odyssey as a whole, their specific importance to the Apologue has not been studied extensively, nor have the connotative resonances of these repeated units been fully explored. The importance of these connotations is elaborated on in the conclusion, where I examine how the meaning derived from these xeinoi encounters interplays with the surrounding story of the Odyssey.National Research Foundatio
Higher education student mobility in Africa: a passage to Nigeria
No full textInternational student mobility is a growing expression of internationalisation. Research has shown that close to 3.7 million international students travelled across the borders of their own country to study in 2009, representing a 77% increase since 2000 (Organisation for Economic Cooperation and Development [OECD], 2011). Historically, the mobility was one-dimensional from South to North, but of late there is evidence of North-South and South–South mobility. Despite being viewed as victims of a brain drain, there is emerging evidence that there are some African countries that play increasingly vital roles in receiving the world’s top higher education students. It is within the context of this emerging evidence that this study examined the phenomenon of student mobility to Nigeria. This study addressed two main research questions, namely: Why do international students choose to leave their country of origin to study in Nigeria? How did international students in Nigeria choose the institution they are currently attending?
This study adopted a qualitative approach using semi-structured interviews and document analysis. The highest ranked public university and the highest ranked private university in Nigeria, according to the Webometrics ranking of 2015, were purposively chosen as the sites for the research. A total of thirty-five international students were involved in face-to-face interviews at both universities. Institutional documents as well as national documents - mainly from the National Universities Commission (NUC) – were consulted in collecting data. This study used the push-and-pull theory of migration to fully understand the phenomenon being studied.
The empirical findings reveal that international students are attracted to Nigeria and the two selected universities for reasons ranging from scholarship opportunities and quality of education offered by Nigerian institutions to parental influence in the choice of Nigeria and the institution at which they study. The study also gave an indication of the impact and influence of terrorism that could be seen as push factors in decisions to study in Nigeria. The study further highlighted the challenges students face both at national and institutional levels as well as making known the improvements that they would like to take place. It was also observed that regional hubs are an emerging trend of student mobility in Africa. It is believed that the recommendations made - if adopted - will go a long way towards enhancing internationalisation strategies for Nigeria and much more for the continent of Africa as a whole.
The study makes a contribution to the body of knowledge regarding the phenomenon of academic student mobility.
Keywords: Internationalisation; student mobility; Africa; Nigeria; push-and pull factors; regional hub; brain drain; international students; university and higher education.National Research Foundatio
A cross sectional comparative study into gender and school's setting on attitudes towards mathematics. A case of selected schools in the Eastern Cape Province
No full textThe organisation, geography and local developmental impacts of heritage tourism in South Africa
No full textHeritage tourism scholarship is a growing domain of research in South Africa and with contributions from a range of different academic disciplines, including geography. Consistent with trends in tourism research most research on heritage and heritage tourism is in the context of countries located in the global North. The opportunities for developing heritage tourism in several countries in the global South has seen a parallel welcome growth of writings on heritage tourism outside of North America, Europe and Australasia. This study focuses on issues relating to an emerging heritage tourism region in the global South, namely South Africa, where heritage tourism was identified early in post-apartheid planning as an important niche for tourism promotion and diversification of product mix, as well as offering unexploited potential for local and regional tourism development. As niche tourism planning has expanded in significance for national policy-makers, heritage tourism has been afforded greater prominence. It is observed that recognition of the importance of heritage tourism extends across the different tiers of government in South Africa from national to provincial to local. At the local scale of government, it is striking that several South African cities have sought to capitalise on aspects of heritage tourism as components of local strategies for urban tourism development, and of broader local economic development planning. This said, heritage tourism so far occupies only a minor position in the growing academic literature on tourism both in South Africa and the wider region of Southern Africa. This study seeks to extend African debates around heritage tourism. The core focus of the study was to analyse the organisation, geography and local impacts of heritage tourism in South Africa. In addition, the study contains a policy focus on identifying the key challenges facing the development of contemporary heritage tourism in South Africa, in terms of maximising its potential as a niche sector of the South African tourism economy. To achieve these research objectives, the study undertook the collection of primary resources, which included a national audit of heritage assets, an analysis of national and local policy documentation and extensive primary interviews with heritage tourists, and local heritage stakeholders...National Research Foundatio
The assessment of the role of social assets in building climate change adaptation : implications for household food security and livelihoods
No full textRural livelihoods are diverse and dynamic, often aimed at managing risk, reducing vulnerability and enhancing food security. In South Africa, rural households pursue different livelihood strategies based on available capital. Household asset endowment consists of physical capital (land, equipment, cattle, etc.), human capital (years of schooling and work experience) and social capital (membership of associations). A household combines these capitals to engage in productive activities. However, climate change remains a threat worldwide. Hence, the household engages in several activities and strategies to earn a living. Climate change affects natural capitals, such as water and land, on which certain livelihoods depend directly. South Africa is predominantly vulnerable to climate change because of its high dependence on climate-sensitive economic sectors: agriculture, fisheries, forestry, and mining. Agriculture is a core sector that ensures food security and provides households with food, employment and other components of livelihood. Smallholder farmers are highly affected by climate change. Thus, adaptation and coping strategies are essential for building resilience. This study seeks to assess the role of social capital, in climate change adaptation of smallholder farmers in Appelsbosch, to improve their food security and livelihoods.
The study was conducted in Appelsbosch, under uMshwathi local municipality in Kwa-Zulu Natal province. Random sampling was used to select a sample of 135 active and long-term smallholder farmers. The participants were interviewed using questionnaires and through focus group discussions. The key informant interviews were held with group representatives and extension officers to gather the in-depth of social capital structure among the farmers and its uses to cope and adaptation strategies against climate change. A Chi-square test was used to analyse the relationships between social capital dimensions, adaptation and coping strategies against climate change. More relationships were tested between social capital and coping strategies used by smallholder farmers to cope with food insecurity. The chi-square test indicated that the relationship between the social group and food insecurity coping strategies employed by the farmer were statistically significant at the 5 % level. Furthermore, the Chi-square test revealed a significant relationship between the social capital and the strategies employed by the household, such as avoiding & limiting soil erosion and water harvesting strategies. Furthermore, there was a significant relationship at the 5% level between the social capital, crop choice and planting schedules.
The study revealed that in Appelsbosch, social capital acts as a conduit for financial transfers and provides information about new skills. An effective system facilitates cooperation among farmers and the sharing of the costs and benefits of adaptation. Effective information dissemination is important. However, participation in these social groups is challenged by factors such as finances, lack of trust and poor leadership among farmers. The results showed that there are more respondents that are highly engaged in farmers’ groups only, compared to those engaged in farmer’s groups and burial societies or grocery stokvels simultaneously. Many explained that this behaviour is a result of members’ dependence on social grants or farm harvests, as their livelihood strategy. Thus, the insufficient monthly income restricts their participation in other kinds of social groups. Therefore, they focus on farming, to sustain their livelihood and food security.National Research Foundatio
Development and validation of a molecular assay and evaluation of the GeneXpert® MTB/RIF assay for the rapid detection of genital tuberculosis
No full textTuberculosis (TB) is a communicable disease which is caused by the bacterium Mycobacterium tuberculosis (MTB). According to the World Health Organization, globally in 2015 there were 10.4 million new cases and 1.4 million deaths due to TB. TB is one of the leading causes of death in South Africa resulting in approximately 8.4% of deaths in 2015. The most common manifestation of TB involves the lungs, defined as pulmonary TB (PTB), while TB affecting other organs is defined as extrapulmonary TB (EPTB). EPTB accounts for only 20% of all TB cases in human immunodeficiency virus negative individuals. Approximately 1.8% of all TB cases have a genitourinary site, with the prevalence of genital TB (GTB) in South Africa reported to range from 6.2-21.0%. One of the leading symptoms of GTB in females is infertility, usually resulting from the involvement of the fallopian tubes and endometrium. Approximately 40-80% of women with GTB will become infertile.
The detection of microorganisms through microscopy is the oldest technique for laboratory diagnosis. While microscopy is rapid and inexpensive, it requires a high bacterial load which is not present in paucibacillary EPTB samples. Culture of MTB is widely regarded as the gold standard for TB diagnosis. While culture has a long turnaround time, culture remains important since it is more sensitive than microscopy. In addition, growth is required for species identification, drug susceptibility testing and genotyping of cultured organisms may be useful for epidemiological studies. Little is known regarding which technique is best for the detection of GTB from clinical samples apart from culture. Molecular based techniques hold the promise of a more rapid and accurate diagnosis of EPTB.
The aim of this project was the development and validation of an in-house nested PCR assay and the validation of the GeneXpert® MTB/RIF (GeneXpert) assay for the laboratory diagnosis of GTB. In total 54 samples were submitted for GTB screening from women being investigated for infertility at the Unit for Human Reproduction, Universitas Academic Hospital, Bloemfontein. This included 44 endometrial tissue samples and 10 menstrual fluid samples. All samples underwent testing with the GeneXpert, the in-house nested PCR and culture. The nested PCR was designed targeting the insertion sequence element 6110 (IS6110) found in members of the MTB complex. The analytical sensitivity/limit of detection (LOD) for the GeneXpert was determined to be 250pg while the LOD for the nested polymerase chain reaction (PCR) was 62.5fg. Both assays displayed excellent analytical specificity by discriminating TB deoxyribose nucleic acid (DNA) from other bacterial and nontuberculous mycobacterial DNA. The diagnostic sensitivity and specificity was determined using culture as the reference method. Culture was able to detect GTB in 2 of the 54 samples including one menstrual fluid and one endometrial tissue sample, thus indicating a GTB prevalence of 3.7%. The GeneXpert detected 1 of the 54 samples as positive indicating a sensitivity of 50% and a specificity of 100%. The nested PCR detected both positive samples resulting in a sensitivity and specificity of 100%. The GeneXpert obtained a positive predictive value (PPV) of 100% and a negative predictive value (NPV) of 98.1%, while the nested PCR obtained a PPV and NPV of 100%. The two GTB isolates underwent genotyping using spoligotyping and mycobacterial interspersed repetitive unit – variable number of tandem repeats (MIRU-VNTR). The menstrual fluid isolate was characterised as a Beijing strain and the endometrial tissue isolate as an X3 strain.
The nested PCR showed a greater sensitivity than the GeneXpert as a result of the better LOD. Despite this, both techniques could be implemented for GTB screening in combination with culture. Screening of menstrual fluid samples using the GeneXpert assay would be well suited for GTB screening in resource limited areas.National Research Foundatio