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Increasing competitiveness through the enhancement of logistics processes in the South African automotive industry

  • Authors: Njokweni, Thobela
  • Date: 2005
  • Subjects: Business logistics , Automobile industry and trade -- South Africa , Competition, International
  • Language: English
  • Type: Thesis , Masters , MTech
  • Identifier: vital:10939 , http://hdl.handle.net/10948/418 , Business logistics , Automobile industry and trade -- South Africa , Competition, International
  • Description: Logistics has become one of the automotive industry's most crucial sub-sectors. Previously, logistics had to step aside to make way for production considerations. Today it is regarded as being every bit as crucial as production in the global village. Advancement of logistics in South Africa is crucial because original equipment manufacturers are producing to developed world standards but are having to cope with low developing world logistics standards. The logistics processes that need to be enhanced in order for the South African automotive industry to be more competitive were investigated. To examine the main problem, three sub-problems were identified. The first sub-problem that has been identified dealt with logistics processes that will enhance the competitive advantage of the South African automotive industry. The second sub-problems looked at key logistics opportunities and threats to the environment in which South African motor manufactures trade. They were investigated by assessing the nature of the South African motor manufacturing industry. Finally, the third sub-problem investigated conclusions that can be arrived at concerning the appropriateness and strategic value of the analysis.
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  • Date Issued: 2005

Influence of grazing by large mammals on the spider community of a Kenyan savanna biome

  • Authors: Warui, Charles M , Villet, Martin H , Young, T P , Jocqué, R
  • Date: 2005
  • Language: English
  • Type: Article
  • Identifier: vital:6889 , http://hdl.handle.net/10962/d1011649 , http://0-www.bioone.org.wam.seals.ac.za/doi/10.1636/CT05-43.1
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  • Date Issued: 2005

Inspectors of education's perceptions of female principalship in the Rundu region of Namibia

  • Authors: Kawana, Irene
  • Date: 2005
  • Subjects: Women school principals -- Namibia -- Rundu , Educational leadership -- Namibia -- Rundu , Sex discrimination in employment -- Namibia , School supervisors -- Namibia -- Attitudes
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:2006 , http://hdl.handle.net/10962/d1015746
  • Description: While women constitute more than 51% of the population and far outnumber men in teaching positions in Namibia, very few occupy positions of leadership. Male candidates are still favoured for top positions, thereby denying women the chance to gain entrance to these positions. One of the reasons for this imbalance seems to be that, in spite of conscious political effort and legislation, women may still be perceived as less effective leaders than men. This research focused on leadership in education, in particular school principals, and explored the perceptions of female principalship held by school inspectors. Three school inspectors from the Rundu Education Region were purposefully selected and interviewed. Inspectors were selected on the grounds of their considerable influence in the selection and appointment of school principals. The study found that these inspectors favour school principals who show commitment to their work, have good interpersonal working relationships, are caring, good listeners, visionary and produce good results. The inspectors attribute female principals’ success to their traditionally perceived characteristics, such as caring leadership and ability to develop good human relations. Instead of perceiving these qualities as professionally negative (as is sometimes argued in the literature) the inspectors see them as indisputable assets to leadership. The respondents acknowledge the cultural stereotyping that may have influenced male attitudes to women in the past, but argue that good leadership is not specific to gender, but part of the qualities a person possesses, regardless of sex. This study concludes that, contrary to what has been reported in many studies, these inspectors perceive women principals as effective – equal to their male counterparts or sometimes even more effective - because they are caring, well organized and good at communicating and establishing relations with others. Though these qualities are different from the traditional masculine qualities which include independence and emotional strength, the respondents recognize and legitimize them as preferred qualities in current effective leadership practice.
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  • Date Issued: 2005

Institutional change and ecosystem dynamics in the communal areas around Mt Coke State Forest, Eastern Cape, South Africa

  • Authors: Cundill, Georgina
  • Date: 2005
  • Subjects: Biodiversity -- South Africa -- Eastern Cape , Ecosystem management -- South Africa -- Eastern Cape , Natural resources -- Management -- South Africa -- Eastern Cape , Sustainable agriculture -- South Africa -- Eastern Cape , Sustainable development -- South Africa -- Eastern Cape , Rural development -- South Africa -- Eastern Cape , Nature conservation -- South Africa -- Eastern Cape
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:4746 , http://hdl.handle.net/10962/d1006959 , Biodiversity -- South Africa -- Eastern Cape , Ecosystem management -- South Africa -- Eastern Cape , Natural resources -- Management -- South Africa -- Eastern Cape , Sustainable agriculture -- South Africa -- Eastern Cape , Sustainable development -- South Africa -- Eastern Cape , Rural development -- South Africa -- Eastern Cape , Nature conservation -- South Africa -- Eastern Cape
  • Description: Through a combination of theoretical discussion and case study analysis from two villages in the Eastern Cape Province, South Africa, this thesis explores the relationship between institutional change and ecosystem dynamics through a multi-scale approach that combines local and scientific knowledge. Several conceptual approaches were combined in this study. These included; the Resilience perspective, the Sustainable Rural Livelihoods approach, the Millennium Assessment framework and principles, and the Environmental Entitlements approach. Various participatory research techniques were employed which combined with GIS technologies, existing data sets, and historical records. Common pool resource areas are social spaces, where local values attached to resources are institutionally mediated, politically nuanced, economically interpreted and historically situated. Political driving forces at various scales have played a disproportionate role in local level institutional functioning in the case study area. In particular, inappropriate state-lead interventions into land use planning have weakened local level institutions, and have reduced the ability of the linked social-ecological system to cope with change and uncertainty. People and ecosystems become more vulnerable when driving forces such as political upheaval, economic depression and drought over-lap. However, rural people are not mere spectators in the face of these driving forces; they respond both reactively and proactively to ensure resilience to change and uncertainty. Ecosystems at Mt Coke play a key role during times of crisis in rural livelihoods. These ecosystems have undergone various short-term cyclical changes largely in response to rainfall fluctuations, and some longer-term changes linked to political events and trends that have affected management practices and local institutions over time. Orthodox ecological interpretations of ecosystem change appear to ignore four key factors identified in this study: 1) the role of institutions in shaping access to resources, 2) the demand for resources in rural livelihoods, 3) the dynamic interaction between social and natural systems, and 4) the interaction between social and natural systems across scales of analysis. The future of common pool resource management lies in the combination of local and scientific knowledge through an adaptive management approach that encourages learning and adaptation in local level institutional structures.
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  • Date Issued: 2005

Interacting effects of wave exposure, tidal height and substratum on spatial variation in densities of mussel Perna perna plantigrades

  • Authors: McQuaid, Christopher D , Lindsay, Justin R
  • Date: 2005
  • Language: English
  • Type: Article
  • Identifier: vital:6879 , http://hdl.handle.net/10962/d1011635
  • Description: A fine time-scale study was undertaken on the effects of wave exposure, tidal height and substratum type on mussel recruit densities on the south coast of South Africa. Prior to sampling, an exposed and a sheltered shore were identified at each of 2 sites (Diaz Cross and High Rocks) 7 km apart. Each shore was divided into 3 shore levels (termed zones) within which 3 substrata (adult mussels, coralline and non-coralline macroalgae) were sampled. Destructive sampling of early (<1 mm) and late (1 to 5 mm) plantigrades was performed daily over 30 d during a period of comparatively high recruitment. Recruitment was synchronised among substrata within zones, but not among zones or between sites. This suggests that larvae will settle on all substrata within a zone, but will prefer some substrata over others. They will not, however, search among zones for favoured substrata. Densities of early (but not late) plantigrades were consistently greater at Diaz Cross than High Rocks, indicating important differences in post-settlement mortality between sites. At both sites, densities of both recruit classes were greater on the low and mid shore than on the high shore. Generally (18 out of 20 comparisons), plantigrade densities within each zone were greater on algae than on adult mussels. Approximately 45% of all recruits collected were found on the foliose coralline alga Corallina, 37% on adult mussels and 18% on the rhodophyte Gelidium pristoides. Without secondary relocation from macroalgae to adult mussel beds, juveniles recruiting onto algae are likely to be lost. On low shore algae, densities of both early and late plantigrades were greater for exposed shores. Densities of plantigrades on the mussel bed and on algae on the mid and high shore were not correlated with exposure. Thus, site, substratum and zone all had significant and interacting effects on the density of recruits on both exposed and sheltered shores. The effect of wave exposure on recruitment, at least on the low shore, suggests that spatial subsidies not only in the form of food supply, but also in the form of larval transport, have a role in structuring mussel populations.
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  • Date Issued: 2005

Interest rate behaviour in a more transparent South African monetary policy environment

  • Authors: Ballim, Goolam Hoosen
  • Date: 2005
  • Subjects: South African Reserve Bank , Monetary policy -- South Africa , Banks and banking -- South Africa , Interest rates -- South Africa , South Africa -- Economic policy , South Africa -- Economic conditions
  • Language: English
  • Type: Thesis , Masters , MCom
  • Identifier: vital:1034 , http://hdl.handle.net/10962/d1004462 , South African Reserve Bank , Monetary policy -- South Africa , Banks and banking -- South Africa , Interest rates -- South Africa , South Africa -- Economic policy , South Africa -- Economic conditions
  • Description: South Africa introduced inflation targeting as a monetary policy framework in 2000. This marked a sizable shift in monetary policy management from the previous "eclectic" approach and the explicit focus on M3 money supply before that. The study appraises the effectiveness of monetary policy under this new dispensation. However, the analysis does not centre on inflation outcomes, which can be a measure of effectiveness because they are the overriding objective of the South African Reserve Bank in effect, it is possible to have a target-friendly inflation rate for a length of time despite monetary policy that is ambiguous and encourages unpredictability in market interest rates. However, persistent policy opaqueness can, over time, damage a favourable inflation scenario. For instance, if the public is unsure about the Reserve Bank's desired inflation target, price setting in the wage and goods markets may eventually produce an inflation outcome that is higher than the Bank may have intended. Rather, this study adjudicates the effectiveness of monetary policy within the context of policy transparency, which is an intrinsic part of the inflation targeting framework. The study looks at the extent to which monetary policy transparency has enhanced both the anticipatory nature of the market's response to policy actions and the force that policy has on all interest rates in the financial system, particularly long-term rates. These concepts are important because through the transmission mechanism of monetary policy, the more deft market participants are at anticipating future Reserve Bank policy the greater the Bank's ability to steady the economy before the actual policy event. With the aid of regression models to estimate the response of market rates to policy changes, the results show that there is significant movement in market rates in anticipation of policy action, rather than on the day of the event or the day after. Indeed, the estimates for market rates movement on the day of and even the day after the policy action are generally minute. For instance, the R157 long-term government bond yield changes by a significant 41 basis points in response to a one percentage point change in the Reserve Bank's benchmark repo rate in the period between the last policy action and the day preceding the current action. In contrast, the R157 bond yield changes by an insignificant 2 basis points on the day of the current repo rate change and about 1 basis point the day after the current change. The results point to a robust relationship between policy transparency and the market's ability to foresee rate action. If this were not the case, it is likely that there would be persistent market surprise and, hence, noticeable movement in interest rates on the day of the rate action and perhaps even the day after. Another important observation is that monetary policy impacts significantly on both short- and long-term market rates. Again, certifying the robustness of monetary policy under the inflation targeting regime
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  • Date Issued: 2005

International relations and change: a Kuhnian interpretation

  • Authors: Schoeman, Jacobus
  • Date: 2005
  • Subjects: Kuhn, Thomas S Kuhn, Thomas S -- Criticism and interpretation International relations International relations -- Philosophy Knowledge, Theory of
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:2830 , http://hdl.handle.net/10962/d1003040
  • Description: Using notions of change developed by Thomas Kuhn, the thesis argues that the rise of globalisation and the end of the Cold War presented the Westphalian or state-centric paradigm of international relations with a Kuhnian paradigm “crisis”. As a result, both the theory and the practice of international relations are in the midst of (what Kuhn calls) a “paradigm shift”. Emerging from this shift is (what is described in this work as) “Access World” and “Denial World” – a particular global configuration of the practice of international relations. Kuhn’s idea of “incommensurability” seems to typify the relationship between the two components of this bifurcated configuration of the international. Both intellectual risk-taking and political courage are required if the ontological struggle raging between “Access World” and “Denial World” is to be settled. This will pave the way for a new paradigm to emerge. Kuhn provides us with the insight that, to achieve this ontological breakthrough, a fundamental change in our vision of the discipline of International Relations, but also of the world of everyday international relations, is required. This entails recasting the study of International Relations as an emancipatory project and by recognising the centrality of human beings in the practice of international relations. Only if this is done, will we be able to arrive at a cosmopolitan political bargain that is appropriate for the 21st century.
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  • Date Issued: 2005

Intraspecific comparison of Phanerochaete chrysosporium strains peroxidase production, pollutant degradation and mycelial differentiation

  • Authors: Fraser, Sheena Janet
  • Date: 2005
  • Subjects: Phanerochaete Pollutants -- Biodegradation Lignin -- Biodegradation Bioremediation Peroxidase Fungi -- Differentiation
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:3964 , http://hdl.handle.net/10962/d1004023
  • Description: The wood-degrading basidiomycete, Phanerochaete chrysosporium, has been studied as a model organism in elucidating the mechanisms and pathways enabling this white-rot fungus to degrade recalcitrant lignin. These same mechanisms are implicated in the mineralisation of environmentally persistent, toxic phenolic chemicals. For this reason, P. chrysosporium has been exploited in a number of environmentally sound technologies, including the degradation of the indigestible lignin component in agricultural waste for the generation of digestible animal feedstocks or high sugar content raw materials for ethanol production; brightening processes in the pulp and paper industry; the detoxification and decolourisation of industrial effluents; and the bioremediation of hazardous waste sites. The improvement of these technologies is dependant on ongoing research involving strain selection, strain development using genetic engineering approaches and process development. Strain improvement using non-recombinant methods is beneficial in that it does not limit the inherent robustness observed amongst natural variants. In this research, through a breeding programme, ten P.chrysosporium sibling strains were screened for variable ligninase activities and pollutant degradation capabilities in order to further describe previously identified differences between these organisms. A conventional stationary liquid culture technique was effectively miniaturised from 10 ml flask cultures to a 96-well microtitre plate format, for the assessment of multigenic traits amongst sibling strains. Using the 96-well microtitre plate method, the relationships between P. chrysosporium growth kinetics, peroxidase production, pollutant sensitivity and pollutant degradation was explored. Significant correlations were primarily associated with P. chrysosporium growth [P < 0.05]. Percentage p-cresol removal and tannic acid tolerance were both correlated with a shorter lag phase in growth [tannic acid: r = 0.7698, P < 0.05; p-cresol: r = 0.7584, P < 0.05] and lower stationary phase biomass levels [tannic acid: r = 0.8177, P < 0.05; p-cresol: r = 0.7803, P < 0.05]. A significant correlation (linear relationship) was also detected between percentage Poly-R478 decolourisation and time of onset of MnP [r = 0.9689, P < 0.001]. No correlation was observed between dye decolourisation, p-cresol degradation, lignin degradation and lignin peroxidase (LiP) or manganese peroxidase (MnP) activities [P > 0.05]. These results imply that differences in the biosynthetic pathways for biomass accumulation in sibling strains play a significant role in the intraspecific variation observed in pollutant sensitivity, pollutant degradation, and enzyme production. Categorical analysis of intraspecific differences was assessed according to four criterions. These included growth, extracellular peroxidase activities, tolerance to toxic pollutants and the biodegradation of model pollutants. Sibling strains showing the most variable responses in three or more of the selective criterion were recommended for further studies. These strains include P. chrysosporium ME446, BS 2.52, BS 13, BS 17, BS 18, and BS 24. Interestingly, BS 2.52 (a dikaryotic strain generating from the crossing of two haploid progeny) showed significantly lower degradation capabilities than the wildtype parent strain ME446. The inherited variability observed between sibling strains is to be further explored through proteome and transcriptome analysis and genetic linkage studies aimed at describing the mechanisms or pathways conferring tolerance to or degradation of environmental pollutants. In examining fewer organisms at this next level, the number of replicates examined can be increased and thus the power of detection of experimental procedures improved, enabling the detection of multigenic traits amongst genetically related organisms. Growth was shown to play a significant role in the intraspecific differences detected in pollutant sensitivity and degradation between sibling strains. Little is known about the mechanism of growth and differentiation, or the role of differentiation in regulating the lignolytic activity in this organism. The membrane gradostat bioreactor and a unique plug-flow membrane bioreactor were evaluated as novel tools with which to further explore the relationship between secondary metabolism, pollutant degradation and biofilm development in sibling strains. High yield MnP production at levels as high as 1478.8 U.l-1 was achieved using a laboratory scale membrane gradostat bioreactor. Furthermore, extensive mycelial differentiation and tissue formation are reported for P. chrysosporium in both the membrane gradostat bioreactor and plug-flow membrane bioreactor. Intraspecific differences in the extent of this differentiation were observed in strains ME446, BS 13, BS 17 and BS 26 cultured using the membrane gradostat bioreactor, highlighting the potential of these techniques as a platform for future strain improvement strategies.
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  • Date Issued: 2005

Introducing hippocratic log files for personal privacy control

  • Authors: Rutherford, Andrew
  • Date: 2005
  • Subjects: Computer security , Internet -- Security measures
  • Language: English
  • Type: Thesis , Masters , MTech
  • Identifier: vital:9743 , http://hdl.handle.net/10948/171 , Computer security , Internet -- Security measures
  • Description: The rapid growth of the Internet has served to intensify existing privacy concerns of the individual, to the point that privacy is the number one concern amongst Internet users today. Tools exist that can provide users with a choice of anonymity or pseudonymity. However, many Web transactions require the release of personally identifying information, thus rendering such tools infeasible in many instances. Since it is then a given that users are often required to release personal information, which could be recorded, it follows that they require a greater degree of control over the information they release. Hippocratic databases, designed by Agrawal, Kiernan, Srikant, and Xu (2002), aim to give users greater control over information stored in a data- base. Their design was inspired by the medical Hippocratic oath, and makes data privacy protection a fundamental responsibility of the database itself. To achieve the privacy of data, Hippocratic databases are governed by 10 key privacy principles. This dissertation argues, that asides from a few challenges, the 10 prin- ciples of Hippocratic databases can be applied to log ¯les. This argument is supported by presenting a high-level functional view of a Hippocratic log file architecture. This architecture focuses on issues that highlight the con- trol users gain over their personal information that is collected in log files. By presenting a layered view of the aforementioned architecture, it was, fur- thermore, possible to provide greater insight into the major processes that would be at work in a Hippocratic log file implementation. An exploratory prototype served to understand and demonstrate certain of the architectural components of Hippocratic log files. This dissertation, thus, makes a contribution to the ideal of providing users with greater control over their personal information, by proposing the use of Hippocratic logfiles.
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  • Date Issued: 2005

Introduction [to the book "Thuthula: Heart of the Labyrinth" by Chris Zithulele Mann]

  • Authors: Wright, Laurence
  • Date: 2005
  • Language: English
  • Type: Book chapter
  • Identifier: vital:7057 , http://hdl.handle.net/10962/d1007419
  • Description: There are certain stories, the world over, that stir our hearts and minds to imaginings richer and deeper than the bald facts of history can easily satisfy. Such is the legend of Thuthula, the young Xhosa girl whose beauty and grace won the heart of Ngqika, chief of the Rharhabe Xhosa; the woman who was later married to his uncle Ndlambe, and then taken by Ngqika to become his wife. The events took place in or around the years 1806 and 1807 in what is now the Eastern Cape Province of South Africa. Prior to the central episode treated in the play, legend has it that Thuthula was out collecting firewood one day with her friends when she knelt at a spring to drink. Startled by the sudden appearance of a hunting dog crossing the stream below the spring, she looked up and saw a handsome young hunter chasing behind the dog. She was struck by his charm and good looks. Teasingly, as any young girl might do, she called her friends round her and challenged the young man to choose his favourite from among them. Amid much flirting and laughter, the object of all this girlish attention was pushed into making a choice. Inevitably, given her beauty, his playful decision fell on Thuthula. This was the first meeting of Thuthula, daughter of Mthunzana, with Ngqika, son of Chief Mlawu.
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  • Date Issued: 2005

Investigating call control using MGCP in conjuction with SIP and H.323

  • Authors: Jacobs, Ashley
  • Date: 2005 , 2005-03-14
  • Subjects: Communication -- Technological innovations , Digital telephone systems , Computer networks , Computer network protocols , Internet telephony
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4631 , http://hdl.handle.net/10962/d1006516 , Communication -- Technological innovations , Digital telephone systems , Computer networks , Computer network protocols , Internet telephony
  • Description: Telephony used to mean using a telephone to call another telephone on the Public Switched Telephone Network (PSTN), and data networks were used purely to allow computers to communicate. However, with the advent of the Internet, telephony services have been extended to run on data networks. Telephone calls within the IP network are known as Voice over IP. These calls are carried by a number of protocols, with the most popular ones currently being Session Initiation Protocol (SIP) and H.323. Calls can be made from the IP network to the PSTN and vice versa through the use of a gateway. The gateway translates the packets from the IP network to circuits on the PSTN and vice versa to facilitate calls between the two networks. Gateways have evolved and are now split into two entities using the master/slave architecture. The master is an intelligent Media Gateway Controller (MGC) that handles the call control and signalling. The slave is a "dumb" Media Gateway (MG) that handles the translation of the media. The current gateway control protocols in use are Megaco/H.248, MGCP and Skinny. These protocols have proved themselves on the edge of the network. Furthermore, since they communicate with the call signalling VoIP protocols as well as the PSTN, they have to be the lingua franca between the two networks. Within the VoIP network, the numbers of call signalling protocols make it difficult to communicate with each other and to create services. This research investigates the use of Gateway Control Protocols as the lowest common denominator between the call signalling protocols SIP and H.323. More specifically, it uses MGCP to investigate service creation. It also considers the use of MGCP as a protocol translator between SIP and H.323. A service was created using MGCP to allow H.323 endpoints to send Short Message Service (SMS) messages. This service was then extended with minimal effort to SIP endpoints. This service investigated MGCP’s ability to handle call control from the H.323 and SIP endpoints. An MGC was then successfully used to perform as a protocol translator between SIP and H.323.
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  • Date Issued: 2005

Investigation into the biological removal of sulphate from ethanol distillery wastewater using sulphate-reducing prokaryotes

  • Authors: Smuts, Lizl
  • Date: 2005
  • Subjects: Sewage -- Purification -- Biological treatment , Prokaryotes , Sulfates , Distilleries -- Waste disposal
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:3941 , http://hdl.handle.net/10962/d1004000 , Sewage -- Purification -- Biological treatment , Prokaryotes , Sulfates , Distilleries -- Waste disposal
  • Description: Ethanol production wastewater is known to be toxic, and is not easily biodegradable. It also consists of a variety of coloured components adding to the complex composition of this wastewater. Disposal of this wastewater into water courses is not recommended and yet is performed all over the world. Investigation of this wastewater found that there was a high concentration of sulphate which, in the presence of sulphate-reducing prokaryotes can cause sulphide corrosion of cement. The concentration of sulphate in the wastewater was approximately 2770 mg/L. It was also found that the wastewater pH was very low and discharge of the wastewater into the wastewater treatment works caused a negative impact on the overall quality of the final wastewater discharged to sea. It was found using FISH techniques that there were no sulphate-reducing prokaryotes present in the wastewaters but that a sulphate-reducing population existed on the sewer wall. An anaerobic contact process was designed to treat this wastewater targeting sulphate reduction to sulphide, to be converted into elemental sulphur and to increase the wastewater pH. The process did not achieve this aim and only approximately 20-30 % reduction in sulphate from the wastewater was achieved with little to no change in the pH. A 95 % reduction in sulphate concentration was needed in order to reach acceptable discharge limits. Sulphate reduction could not be carried out, even under ideal laboratory conditions. It was found that the barrier causing the digester failure was the high concentration of phenols present in the wastewater (3.3 g/L) together with the production of high concentrations of volatile fatty acids (on average 13 g acetic/L). These two components are known to cause digester failure, especially phenols, and phenols are usually only degraded by fungal species. It was concluded that the wastewater itself was not amenable to this method of biological treatment.
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  • Date Issued: 2005

Investigation of the effect of selected polypropylene fibres and ultra-fine aggregate on plastic shrinkage cracks on South African roads

  • Authors: Kluyts, Grant
  • Date: 2005
  • Subjects: Concrete roads -- South Africa -- Design and construction , Fiber-reinforced concrete , Reinforced concrete -- Cracking , Concrete -- Expansion and contraction , Polypropylene fibers
  • Language: English
  • Type: Thesis , Masters , MTech
  • Identifier: vital:9592 , http://hdl.handle.net/10948/174 , Concrete roads -- South Africa -- Design and construction , Fiber-reinforced concrete , Reinforced concrete -- Cracking , Concrete -- Expansion and contraction , Polypropylene fibers
  • Description: Plastic shrinkage cracks, although not inherently structurally debilitating, expose the reinforcement in low-volume reinforced concrete roads to deleterious substances, which may reduce its effectiveness leading ultimately to structural failure. In un-reinforced low-volume concrete road these cracks appear unsightly and cause the road user an unpleasant riding experience. Many researchers believe that plastic shrinkage crack development remains a concern to the concrete industry, occurring in particularly large–area pours such as low-volume concrete roads, and therefore requires further research to understand their formation and minimization. This study reports findings on the effectiveness of oxyfluorinated polypropylene fibres to control plastic shrinkage cracks, and the effect the addition of ultra-fine material has on the formation and/or propagation of these cracks. Findings indicate that low volume dosages (2 kg/m³), of oxyfluorinated polypropylene fibre significantly reduced the formation of plastic shrinkage cracks under test conditions. Furthermore, that the addition of ultra-fine material in excess of 63 kg/m³ increased the formation and/or development of plastic shrinkage cracks.
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  • Date Issued: 2005

Isolation and characterization of a novel thermostable and catalytically efficient laccase from Peniophora sp. strain UD4

  • Authors: Jordaan, Justin
  • Date: 2005
  • Subjects: Enzymes Enzymes -- Industrial applications Peniophora Laccase
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:3970 , http://hdl.handle.net/10962/d1004029
  • Description: Enzymes are becoming an effective tool in industrial processes, from crude applications such as bioremediation to fine processes such as chirally selective biocatalysis. The ligninolytic enzymes have recently received considerable attention for industrial application due to both their broad substrate range and their ability to degrade the most recalcitrant natural polymer, lignin. This group of enzymes was therefore identified as the target group for this study. Improved enzyme properties are constantly being sought to enhance the range of applications for enzymes. Biodiversity provides a wide variety of enzymes. Several researchers have concentrated on extremophiles as their primary source of superior enzymes, consequently neglecting temperate environments in their search for these enzymes. The relatively neglected fungal biodiversity of South Africa provided an opportunity to test the hypothesis that potentially important industrial enzymes with unusual properties could be isolated from mesophilic basidiomycetous fungi. Subsequent screening of Eastern Cape biodiversity for thermostable ligninolytic enzymes from basidiomycetes resulted in the isolation of a novel laccase enzyme from a basidiomycetous species. This fungus was identified as Peniophora sp. UD4 by phylogenetic analysis of rDNA ITS sequences. Initial studies indicated a superior optimum temperature of 70°C and thermostability, indicated by no loss in activity at 60°C over nine hours. Further characterization of the laccase revealed a broader than usual substrate range through its unusual ability to oxidatively couple DMAB and MBTH. The laccase also exhibited a broad pH oxidation range for ABTS (pH 2 – 6.8), and a relatively high affinity (K_m_ = 0.0123 mM) and catalytic efficiency (63 252 mM^(-1)^s^(-1)^) for ABTS as a substrate. The laccase activity from Peniophora sp. UD4 was shown to be comprised of three isozymes with a molecular weight of 62 kDa and pI’s of 6.33, 6.45 and 6.50. Investigation of the nutrient and physical factors affecting ligninolytic enzyme production and growth of Peniophora sp. UD4 indicated that the wild-type organism was unsuitable for large scale production of the thermostable laccase due to the low levels of laccase production. The thermostable laccase was applied to defouling of ultrafiltration membranes, bioremediation of industrial waste streams, biocatalysis, and biosensor technology as potential applications. Application of the Peniophora sp. UD4 laccase to defouling of membranes used for ultrafiltration of brown water showed large flux recoveries of 31, 21 and 21% after the first three defouling recycles respectively, compared to 3% for the control without immobilized enzyme. The novel laccase showed potential for the bioremediation of industrial waste streams, the most successful being that of bleach plant effluent, where a reduction of 66% of the phenolic load was achieved. Application of the novel laccase to biocatalytic oxidation of ferulic acid and (±)-α-pinene showed higher product yield as compared to oxidation of these compounds by Trametes versicolor laccase in mediated and non-mediated systems. The major products of (±)-α-pinene oxidation were identified as verbenol and trans-sorberol. The Peniophora sp. UD4 laccase was successfully applied to biosensor technology, which benchmarked significantly better than Trametes versicolor laccase for the detection of 4-chlorophenol. The biosensor developed with laccase from UD4 by covalent binding to a glassy carbon electrode exhibited the best combination of sensitivity and stability. This thesis shows that a laccase with superior properties was obtained from a mesophilic South African basidiomycete. The catalytic properties displayed by the novel laccase from Peniophora sp. UD4 all contribute to the increased industrial applicability of laccases, and may be the most industrially feasible enzyme of its class isolated to date.
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  • Date Issued: 2005

Isolation, purification and characterization of inulin and fructooligosaccharides from chicorium intybus and inulinase from aspergillus niger

  • Authors: Mavumengwana, Vuyo Bhongelethu
  • Date: 2005
  • Subjects: Aspergillus , Inulin , Chicory -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:3954 , http://hdl.handle.net/10962/d1004013 , Aspergillus , Inulin , Chicory -- South Africa
  • Description: Inulin is a non-digestible carbohydrate fructan polymer consisting mainly of β (1→2) fructosyl fructose links. Enzymatic hydrolysis of inulin by inulinase results in the production of low D.P (degree of polymerization) oligosaccharides also called fructooligosaccharides(FOS). Isolation of inulin from chicory root (Chicorium intybus) was achieved by first, extraction using deionized water (600C), followed by carbonation (0.1 M Ca(OH)2 and CO2 gas). This was filtered in order to remove the non sugars, thereafter, treated successfully with polyamide 6 powder. A cation exchanger and an anion exchanger were used to further exclude other components such as tannins and pigments. The extracted inulin was quantified using the Somogyi-Nelson colourimetric assay. Chicory root (207 g, 30 % being water) yielded 30 g of the raw extract. A 100 mg of the raw extract was assayed and found to contain 11 % yield of inulin which was 80.2 % in purity and 4 % free fructose. Analysis of the crude and purified inulin extracts on the MALDI TOF spectrometry showed the samples to have a DP of 2 to 22 and 2 to 27 respectively. Maximum inulinase production from Aspergillus niger grown on inulin was observed after 60 hours. The enzyme activity was found to be 1.168 U/ml with a temperature and pH optimum of 30 °C and 7.7 respectively. The enzyme proved to be unstable as it progressively lost its total activity during attempts at purification.
  • Full Text:
  • Date Issued: 2005

It's a happy day

Knowledge levels of school learners before and after a life skills program on rape and child abuse

  • Authors: Britz, Cecelia Adonia
  • Date: 2005
  • Subjects: Rape -- Prevention , Child abuse -- Prevention , School children -- Life skills assessment -- South Africa -- Port Elizabeth
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:11017 , http://hdl.handle.net/10948/360 , Rape -- Prevention , Child abuse -- Prevention , School children -- Life skills assessment -- South Africa -- Port Elizabeth
  • Description: Due to the early age at which children are exposed to rape and child abuse, preventative programs should be implemented as early as possible. Schools provide ample opportunity to reach learners of all ages. Educators have regular contact with learners and have a key role to play in the implementation of comprehensive health and education life skills programs. Non-Governmental Organisations (NGO) can link up with schools to combat abuse that affects children in South African communities. The Ubuntu Education Fund requested the Health and Development Research Institute (HDRI) of the University of Port Elizabeth to assist with the evaluation of the Mpilo-Lwazi life skills program for grade 6 to 9 learners at 5 primary and 5 secondary schools in the Nelson Mandela Metropole. The schools were selected by non-probability convenience sampling and the learners via simple random sampling. The life skills program addressed issues of HIV/AIDS, STI and rape and child abuse and the requested evaluation encompassed both the quantitative pretest-posttest assessment of knowledge plus a qualitative focus group assessment of perception of the content and presentation of the life skills program. A multiple pretest-post-test quasi-experimental research design was used. This study focused on the quantitative aspect of rape and child abuse and aimed to describe learners’ base line knowledge before receiving education in rape and child abuse life skills programs and acquired knowledge after the program had been implemented. Descriptive statistics were employed to describe the pre and post test information and the Hotelling’s T2 was used to identify variation in profiles. Posthoc t-tests established significant differences between grades. Structured questionnaires were used to achieve the aims of the research. Results of both the quantitative and qualitative findings were collated to be presented to the Ubuntu Education Fund. The results of the study were as follows: ix The results indicated that the overall level of knowledge regarding Rape and Child Abuse among the sample of grade six to nine learners was average. A small increase in knowledge was identified in the post-test. The area most successful for knowledge increase was the section relating to general information on the victims of Rape and Child Abuse. An area where knowledge actually decreased was that on reporting the rape or abuse. Knowledge of rape and child abuse alone is not sufficient to bring about change in behaviour. Changes in beliefs, such as increased awareness that rape and child abuse are prevalent in families and communities, and attitude change are necessary to facilitate the adoption of health-promoting behaviour. Future education efforts need to introduce health educators into the Rape and Child Abuse life skills program at schools in educating the learners. The format of teaching should also take into account the preferred method of presentation indicated by the learners as this would facilitate optimal intake of information.
  • Full Text:
  • Date Issued: 2005

Kuba wena molokazana

Kuzade kubenini bendilandela

Language is culture:

  • Authors: Malila, Vanessa
  • Date: 2005
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/159256 , vital:40281 , https://hdl.handle.net/10520/EJC146402
  • Description: Many of us think that English dominates the web pages we surf each day. Indeed, until recently English was the predominant language for publishing online, but things are slowly changing and the presence of linguistic diversity on the Internet is starting to become a reality in the global village. The question, however, remains: how many African languages are represented in that diversity?.
  • Full Text:
  • Date Issued: 2005
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