Performance analysis of voltage regulating relays with circulating current control algorithms using hardware-in-loop real-time simulator techniques

Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2010.Electrical power distribution networks are required to provide power to customers at nearconstan

Muddy Realities of Organizational Existence: Should HRD Dive in or Take an Ostrich Defense from the Sidelines? Review of Literature, Framework Development and Future

Workforce management goes beyond the management of people and the management of human resources processes and projects, to deciphering organizational climate of operation, activities and behaviors that could hinder organizational progress thereby negating good strategy implementation plans. This chapter intentionally selected several challenges that usually entangle organizations, throwing them into muddy pools where entangling meshes of corruption, workplace incivility, stigmatization, crises and management failure among others envelope and bring some of these organization to their perilous ending. The chapter asserts that the field of Human Resources Development (HRD) could play a meaningful role in the identification of organizational challenges and the initialization of the designing and implementation of interventions that could address systems blockages. By getting inside the challenging muddy pools, HRD would assume a strategic position in redefining its purpose of existence by decoding organizational bottlenecks and introducing interventions that could create new paths and new avenues for organizational effectiveness and sustainability even during environmental turbulences. Through a detailed discussion of negative issues bedeviling organizations, including the crisis brought by the corona virus pandemic that has not spared organizations either, this chapter asserts that HRD cannot take an ostrich defense of burying its head in the sand while chanting the ‘I see no evil, I hear no evil’ slogan pretending that challenges bedeviling organizations are not HRD’s concern. The chapter asserts that through new research pathways and the provision of appropriate interventions, HRD has great potentialities of removing systems blockages and supporting both leadership and the workforce to be flexible and adaptable to environmental turbulences of organizational operations

'Suddenly the film scene is becoming our scene'! the making and public lives of black-centred films in South Africa (1959-2001)

ABSTRACT Through an examination of the making and public lives of a selection of apartheid and post-apartheid black-centred films in South Africa: Come Back, Africa (1959), u’Deliwe (1975), Mapantsula (1988), and Fools (1997), their contexts of production, circulation, appropriation and engagement, I investigate the role of film in the public life of ideas. While my focus is chiefly on film, I introduce a brief comparator with the television series Yizo Yizo (1999-2001), where I deploy the same methodology. To this end, I ask how these films relate to ongoing contemporary discourses about black identity. To explain the making and extended public lives of the films, I combine elements of public sphere theory, literary theory and film analysis to develop a theoretical model that treats film as a circulating text open to appropriation and engagement over time. The results indicate that in ways that shifted throughout the films’ public lives, their genres, modes of circulation as well as contexts of their appropriation, mediate the manner and extent of their relations to critical public engagements of black identity. I argue that through the combination of its nature as a modern form and its specific generic attributes, with the conditions and circumstances of its circulation and engagement, film stimulates critical public engagements of certain types. Film achieves what I have called public critical potency, when its content directly or otherwise, resonates with contemporary social and political struggles. Through its public critical potency, which is the capacity of film to stimulate critical public engagements, film demonstrates its importance in the public life of ideas. However, film also has the potential to fail in that respect. As a result, the margin between its success and potential for failure to achieve public critical potency, makes precarious, the role and status of film in the public life of ideas. In examining film as a circulating text over time, the thesis challenges approaches that investigate the public sphere of film solely in terms of genre and cinematic spectatorship. In the process, it has engaged the concepts of ‘film’ and ‘public’ within film studies in a way that recognizes its wide reach and extensive role in the public sphere. In the final analysis, the thesis is instructive with regard to the ways in which film may or may not relate to the public sphere in repressive and post-repressive societies in particular, and in modernity in general

Yield and quality of potatoes as affected by calcium nutrition, temperature and humidity

Potato tubers are low in calcium due to limited calcium transport in the xylem and immobility of calcium in the phloem. Low tuber calcium content results in the occurrence of necrotic cells in the medullary tissues, which is a physiological disorder known as internal brown spot (IBS). A high incidence of IBS results in reduced tuber quality and market value. The objective of the study was to apply additional calcium to the potato crop using different calcium sources (gypsiferous mine water, gypsum and calcium rich water) to determine the impact on tuber yield and quality. Commercial field trials were conducted at Kleinkopje mine on the Mpumalanga Highveld from August 2001 to January 2002 and from September 2002 to January 2003. The response of the potato cultivar Up-to-date to irrigation with gypsiferous mine water as a calcium source was investigated. At Kleinkopje there was no control field (irrigated with normal water) for direct comparison. Another field trial was established at University of Pretoria Experimental Farm where gypsum at four levels was broadcast and incorporated prior to planting. Pot trials were conducted under controlled conditions because calcium uptake is not affected only by the amount of calcium applied or the location of the calcium application. Factors that affect calcium uptake such as temperature and humidity also play a role. Two pot experiments were conducted under controlled conditions from July to October 2002 and from October 2002 to January 2003. In these experiments, the effect of applying increasing calcium concentrations in calcium rich water at high (27/17oC) and low (22/14oC) controlled temperatures and humidities (35% and 85%) on tuber calcium content and quality were investigated. The parameters measured included growth analysis, leaf and tuber chemical analysis, tuber yield and quality. For the field trials soil sampling was done at the beginning and at the end of the cropping season for chemical analysis. Irrigation with gypsiferous mine water did not have a negative impact on overall potato growth. Higher levels of calcium (in irrigation water or gypsum) also did not have a negative effect on other nutrient levels. Irrigating potato plants with gypsiferous mine water resulted in high tuber yields of 52 t/ha in 2001 and 62 t/ha in 2002 seasons, which are good yields for Mpumalanga. Applying higher gypsum levels as a preplant broadcast resulted in high tuber yields (52 t/ha), which is a good yield for Hatfield. Application of gypsum as a preplant broadcast and irrigation with gypsiferous mine water resulted in good quality tubers (SG > 1.075 and chip colour > 45). This implies that gypsiferous mine water can possibly be used for irrigation of potatoes as a calcium source. The calcium nutrition of the potato tubers was not affected by the amount of calcium applied to the plants, calcium uptake or distribution within the plant only. Environmental conditions (temperature and humidity), which affect these functions also played a role. It has been discovered that lowering the temperature (22/14oC) and low humidity (35%) had beneficial effects on the tuber yield. Maintaining plants at low temperature (22/14oC) and high humidity (85%) could improve the tuber quality. However, high humidity (85%) and high temperature (27/17oC) improved calcium uptake by the tubers.Dissertation (MSc (Agric) Agronomy)--University of Pretoria, 2007.Plant Production and Soil ScienceMSc (Agric)unrestricte

Evaluating the benefits of cloud computing in small, medium and micro-sized enterprises (smmes)

Cloud computing is becoming an essential tool in lowering Information Technology (IT) costs amongst Small, Medium and Micro-sized Enterprises (SMMEs). As such amongst a myriad of challenges, SMMEs are faced with a general lack of resource capability including the lack of Information and Communications Technology (ICT) infrastructure and skills. This further disables the SMMEs ability to compete with big business and industry peers. As such cloud computing offers SMMEs the ability to access high level ICT services either through SaaS (Software-as-a-Service), PaaS (Platform-as-a-Service) or IaaS (Infrastructure-as-a-Service) service delivery models. Cloud computing adoption amongst SMMEs is relevant in the sense that SMMEs can realise the full benefits of reduced capital expenditure, improved access to ICT systems, heightened security of data and low costs for agile development amongst a myriad of cloud computing benefits

Factors associated with long hospitalisation for psychotic disorder patients in an acute ward: Tertiary care hospital

Background: The average length of stay is often used to indicate health system efficiency; shorter stays are associated with reduced costs. In South Africa, mental healthcare expenditure is spent on inpatient care. Aim: To identify factors associated with a long stay in an acute psychiatric unit. Setting: A tertiary hospital. Methods: A case-control study review of inpatients diagnosed with psychotic symptoms was used. Sample was divided into two groups, length of stay (LOS) (LOS greater than 21 days, LOS less than 14 days). Total of 82 patients were divided into short stay group (SSG, n = 23) and long stay group (LSG) (n = 59). A comparison of demographic, clinical and system variables was conducted. Results: In demographics, LSG had fewer men compared to SSG (78.3%) and differed statistically from LSG with p = 0.05. Long stay groups were older in comparison to SSG with a p = 0.02. Illicit substance use in LSG was 44.1% and statistically less than SSG (73.91%; p = 0.02). A high proportion of LSG had medical or surgical and psychiatric comorbidities (67.8%) compared to SSG (43.5%) (p = 0.04). A total of 95% patients in SSG had family support. Conclusion: Longer stay was found to be associated with older females with primary psychotic disorders. Comorbidities with less availability of family support were associated with younger males presenting with psychotic symptoms that may be related to illicit substances that respond to rapid stabilisation. Contribution: Active surveillance of medical comorbidities amongst older female patients is necessary for early liaison services to reduce their length of stay

The Textualities of the AutobiogrAfrical

In your mind’s eye, summon a map of the world—that famous text. There, there is Africa. The familiar, highly visible bulge of head to horn and curve, and the islands as you travel down to the continent’s southernmost point. It is likely that your imagination, like ours, has archived the inherited template of a Mercator projection, the powerful sixteenth-century cartography which remains influential offline and e-nfluential on Google Maps, even though it misleadingly distorts the size of continents. The 30.2 million square kilometers of the African continent appear much smaller than, say, the areas of the US (9.1 million square kilometers), Russia (16.4 million square kilometers), or China (9.4 million square kilometers). In comparison, the corrective cartographic morphing of the GallPeters projection revises the habituated representational geography of the world’s landmasses, showing the relational sizes of continents more accurately.1 Such tensions are not surprising, for the map, we know, is not to be equated with the territory and, in the context of our interest in this special issue in the textualities of the AutobiogrAfrical, divergent cartographies of the same space, drafted from different ideological perspectives, remind us to ask questions about how life narratives might make Africa intelligible. If, as Frances Stonor Saunders observes, “the self is an act of cartography, and every life a study of borders,” then “[e]nvisioning new acts of cartography that give substance and dynamism to the spaces between borders … produces new selves—or, at the very least, new ways of thinking about selfhood—and thus new objects of autobiographical enquiry.” 2 Any map of Africa reflects assumptions about a collective (“Africa”), as well as the political-geographical divisions of nation-states. “Africa” implies degrees of commonality among the (possibly more than) fifty-four countries that comprise the continent. Yet we know the dangers of a single story. Africa is not, after all, a country. Bear in mind, too, that our editorial team is located at the bottom end of the continent in South Afric

Comprehensive analysis of Callistemon citrinus and essential oils using 2-D GCxGC-TOF/MS

Abstract: The study was aimed at extracting essential oils from Callistemon citrinus and Cymbopogon citratus, performing extensive characterisation of the extracted oils and investigating their antimicrobial effects against a batch of pathogens. These two plants are commercially known as Lemon bottlebrush tree and Lemon grass, and were chosen because of their documented history in having bioactive properties such as antioxidant, anti-inflammatory, anti-cancer, antibacterial, and their beneficial effects particularly in the cosmetics, pharmaceutical and food industry. Plant samples were prepared by extracting the oils from the plant materials using various solvents by means of a soxhlet extraction method. Upon selecting three different solvents for the extraction, the procedure was based on phytochemical isolation. Dichloromethane, a polar solvent was used for extracting phyto-constituents such as alkaloids, terpenoids, fatty acids, flavonoids. Ethanol, a semi –polar solvent was used for extracting alkaloids, tannins, polyphenols, flavonols, terpenoids and sterols. Lastly hexane, a non-polar solvent used to extract terpenoids, tannins, polypeptides, anthocyanin. All these solvents were used selectively and after completion, the extracted materials/essential oils were air dried and diluted with different solvents for further analysis. GCxGC-TOF/MS was the selected separation technique to confirm that indeed the secondary metabolites found had bioactive properties. A biological test was conducted as well to confirm the bioactive properties by testing the essential oils against 11 common pathogens namely Bacillus subtilis, Klebsiella oxytoca, Proteus mirabilis, Staphylococcus aureus, Mycobacterium smegmatis, Enterobacter cloacae, Staphylococcus epidermidis, Enterococcus faecalis, Proteus vulgaris, Escherichia coli and Klebsiella pneumonia. Analysis of the oils by GCxGC TOF/MS revealed the presence of a total of 300 compounds in Cymbopogon citratus and Callistemon citrinus. Neral (Citral) was found to be a major compound in Callistemon citrinus oil and Mycrene was found to be a major compound in Cymbopogon citratus oil. Compounds like sulcatone, linalool, ocimene, citronellol, geraniol and eucalyptol were also common in the oils...M.Sc. (Chemistry