The investigation of the hydrolysis reaction of m-phenylene to resorcinol
- Authors: Khaile, Thebeeapelo John
- Date: 2002
- Subjects: Resorcinol
- Language: English
- Type: Thesis , Masters , MTech (Chemistry)
- Identifier: vital:10961 , http://hdl.handle.net/10948/107 , Resorcinol
- Description: The purpose of this study was to characterise the resinous material formed during the acid catalysed hydrolysis of m-phenylenediamine (MPDA) to resorcinol, and to establish a reaction mechanism that could explain the formation of both resorcinol and the resinous materials in the reaction. A further objective was to determine reaction conditions that would lead to reduced formation of the resins during the hydrolysis reaction. The number of compounds present in a sample taken during the course of the hydrolysis reaction was determined by HPLC fitted with a photodiode array detector. Five main components were detected. These compounds were identified as mphenylenediamine, m-aminophenol, resorcinol, 3,3’-aminodiphenylamine and 3- amino-3’-hydroxydiphenylamine by means of GC-MS. 3,3’-Diaminodiphenylamine is formed by self-condensation of MPDA and 3-amino-3’-hydroxydiphenylamine is formed by the reaction of MPDA with resorcinol. The degree of formation of these intermediates is substantially reduced when MPDA is added dose-wise to phosphoric acid at a reaction temperature of 220oC. The reaction mechanism of the hydrolysis reaction was investigated by isotopic lable incorporation, followed by analysis by NMR. This was done by hydrolysing MPDA using deuterated phosphoric acid (D3PO4). D3PO4 was generated by dissolving phosphorus pentoxide in deuterium oxide. The resorcinol product obtained from the hydrolysis using D3PO4 was found to be deuterated on the C-2, C-4 and C-6 positions. This suggests that the hydrolysis reaction involves protonation of MPDA on these positions, and this results in the formation of an iminium ion as one of the resonance forms. Hydrolysis then occurs on the positively charged carbon of this species. Fertiliser grade phosphoric acid can be used in the hydrolysis reaction, provided sulphates are removed before the acid is used in the hydrolysis reaction. The hydrolysis reaction using either ammonium sulphate or sulphuric acid produces resorcinol in yields lower than 60% if the hydrolysis is conducted in one pass. If these catalysts are used in the hydrolysis reaction, the reaction mixture needs to be re-heated after removal of resorcinol in order to increase the yield. Hydrolysis of MPDA using zirconium phosphate as catalyst gave resorcinol yields in excess of 90% over 24 hours. These reactions were carried out at very low concentrations of MPDA (0.3%). The mode of catalysis in these reactions is unclear. There is a possibility that the reaction is catalysed by phosphoric acid that leaches out of zirconium phosphate at high temperatures. The reaction might therefore not differ mechanistically from the phosphoric acid catalysed reaction. Further studies are required to clarify this point.
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- Date Issued: 2002
Chemical studies of selected chromone derivatives
- Authors: Nchinda, Aloysius Tchangwe
- Date: 2002
- Subjects: Heterocyclic compounds
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4434 , http://hdl.handle.net/10962/d1007442
- Description: This investigation has been geared towards several aspects of chromone chemistry. Selected 2-(N,N-dimethylarnino)chromones have been synthesized via 2-hydroxyacetophenone boron difluoride complex intermediates, and potentiometric analysis of these compounds in ethanolwater has been used to determine the influence of substituents on their basicity. The pKa values have been found to lie within a narrow range (1.92 - 2.52), and the observed substituent effects have been rationalized with the aid of semi-empirical and ab initio molecular orbital calculations. An efficient route has been developed for the synthesis of the naturally-occurring chromone, "granulosin" [7,8-(methylenedioxy)-2-propylchromone], and several C-2 side chain analogues in good yields, by condensing 2'-hydroxy-3',4'-(methylenedioxy)acetophenone with a range of ethyl carboxylate esters. These compounds show significant cytotoxic activity against the brine shrimp, Artemia salina, and two of them, the 2-ethyl and 2-benzyl derivatives also show 100% activity as pesticides on Beet army worms (BAW). Another naturally-occurring chromone derivative, 5-hydroxy-2-isopropyl-7-methoxychromone, and four C-2 side chain analogues have been prepared in moderate yields. These compounds also show significant cytotoxic activity against the brine shrimp, Artemia salina, and it is apparent that the presence of the hydroxyl group at C-5 is critical for such activity. The electronimpact mass spectra of both series of chromone derivatives have been investigated, permitting the elucidation of characteristic fragmentation patterns. In work directed towards the synthesis of potential HIV -1 protease inhibitors, five novel chromone-containing analogues of the clinically useful drug, ritonavir, have been synthesized. The design strategy has involved the coupling of substituted chromone-2- carboxylic acids with a specially prepared, hydroxyethylene dipeptide isostere to afford ritonavir analogues containing chromone termini. An interactive docking procedure has been used to explore the docking of ritonavir and the novel chromone-containing analogues into ' the active site of the enzyme, and has indicated the capacity of the ritonavir analogues to form hydrogen-bonds with the HJV-l enzyme receptor. Various substituted cbromone-3-carbaldehydes, which have been synthesized from the corresponding o-hyclroxyacetophenones using Vilsmeier-Haack methodology, have been examined as substrates for Morita-Baylis-Hillman reactions, using 3-hyclroxyquinuclidine as the catalyst and arcylonitrile and methyl acrylate as the activated alkenes. Optimization of the reaction conditions has permitted efficient conversion of the cbromone-3-carbaldehydes to the Morita-Baylis-Hillman products and, in some cases, dimeric products, within 24 h. Heating of the Morita-Baylis-Hillman products, arising from reactions with methyl acrylate, at 80 ºC for 3 h in the presence of DABCO as catalyst, has been shown to effect transformation to the corresponding dimers in good yield.
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- Date Issued: 2002
Mandendende
- Authors: Venda men and boys , Tracey, Andrew T N
- Date: 2002
- Subjects: Venda, (African people) , Folk dancing, Venda , Reed pipes (Organ pipes) , Drum , Instrumental music , Sub-Saharan African music , Africa South Africa Venda f-sa
- Language: Venda
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/112125 , vital:33550 , International Library of African Music, Rhodes University, Grahamstown, South Africa , ATC126a-05
- Description: Instrumental Venda Tshikona reed pipe dance music.
- Full Text: false
- Date Issued: 2002
The immobilization of Microcystis aeruginosa PCC7806 on a membrane nutrient-gradostat bioreacator for the production of the secondary metobolites
- Authors: Strong, Peter James
- Date: 2002
- Subjects: Microcystis aeruginosa , Myrocystins , Bioreactors
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11083 , http://hdl.handle.net/10948/283 , Microcystis aeruginosa , Myrocystins , Bioreactors
- Description: A module and an inoculation technique were developed that would allow for the efficient immobilization of Microcystis aeruginosa PCC7806 on a synthetic membrane. A variety of module types, membranes (ceramic, tubular polyethersulfone and externally skinless polyethersulfone capillary membrane), and methods of immobilization (adsorption, pressure filtration and a developed technique that involved drying a cell slurry on a membrane) were assessed. The morphological properties that affected the immobilization of Microcystis aeruginosa PCC7806, as well as the effects of immobilization upon cell morphology were assessed. Cells in the stationary growth phase, which had a well-developed extra-cellular polysaccharide layer and no gas vesicles, were optimal for immobilization. Microcystin production under immobilized conditions was assessed under different nitrate concentrations, light intensities, biofilm thickness and immobilization times. Additional work included assaying for Microcystin production of two airlift-grown cultures under a high light intensity and complete nutrient deprivation and the inoculation of a ceramic membrane. An immunological technique was used to elucidate where toxin production was greatest within a biofilm immobilized upon an externally skinless polyethersulfone capillary membrane. The externally skinless polyethersulfone capillary membrane was evaluated to assess homogeneity and the physical differences between membrane batches that led to the erratic, incomplete biofilm formation, as a biofilm of a constant thickness could not be immobilized. Microcystis aeruginosa PCC7806 was exposed to a variety of solvents in order to permeabilize the cyanobacteria, as that would have enabled a truly continuous extraction process for the metabolite. FDA hydrolysis had to be optimized in order to use it as an indicator of cell viability. In addition a single-step extraction of Microcystin was attempted using live bacteria. A capillary membrane module, containing the externally skinless polyethersulfone capillary membrane, inoculated using pressure filtration, was the most efficient combination to establish a biofilm. Cells that were no longer actively dividing and that lacked buoyancy displayed superior immobilization to cells that were actively dividing and buoyant. The immobilized cells did produce Microcystin but in much lower concentrations to cells grown in an airlift culture. Biofilms grown with a higher nitrate concentration, a lower biofilm thickness and a lower light intensity had a higher specific microcystin content, while biofilms with a higher nitrate concentration a lower light intensity and a longer growth period displayed the a greater toxin production per mm2 of membrane. Microcystin occurred at its highest concentration in cells just above the pore opening. The diffusion of nutrients occurred relatively quickly to the outside layers of the biofilm, with a true gradient being established laterally from these nutrient veins that were above the pores. Permeabilization of the cells proved unsuccessful, as cells that remained viable did not release the intracellular compound into the surrounding medium.
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- Date Issued: 2002
"Effulgent in the firmament" the politics of representation and the politics of reception in South Africa's 'poetry of commitment', 1968-1983
- Authors: Mde, Vukani
- Date: 2002
- Subjects: South African literature -- Black authors -- History and criticism , Politics and literature -- South Africa -- History -- 20th century , Literature and state -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10987 , http://hdl.handle.net/10948/288 , South African literature -- Black authors -- History and criticism , Politics and literature -- South Africa -- History -- 20th century , Literature and state -- South Africa
- Description: This dissertation re-examines an era in the production and reception of English language poetry in South Africa by black writers. Intellectually the 1970's was the Black Consciousness phase of South African history and very few aspects of life in the country were untouched by the intellectual movement led by Steve Biko and other young black student leaders. The aesthetic and literary output of the time, like all other facets of South African life, exhibited the influence and pressures brought to bear by Black Consciousness. Moreover, the Black Consciousness poets introduced the most vibrant and innovative phase for English language poetry produced in South Africa. It is my contention, however, that such vibrancy and innovation has consistently been compromised by unsympathetic, often hostile, and almost-always ill-informed criticism. The dissertation offers a critique of the academic and journalistic practice of criticism in South Africa. I argue that critical practice in South Africa has been engaged throughout the twentieth century in the discursive enforcement of ‘discipline’. In his Discipline and Punish (1977) the French post-structuralist philosopher Michel Foucault demonstrated how power is wielded against oppressed/suppressed groups through self regulated proscriptions, and argued that power is a discursive rather than a corporeal phenomenon. My dissertation follows Foucault in reading the critical reception of Black Consciousness poetry as the practice of disciplinary power. The dissertation also engages critically with the poetry of Oswald Mtshali, Mongane Serote and Sipho Sepamla, and argues that their work is the inscription of black subjectivity into the literary and cultural mainstream. It situates their work within wider 6 societal debates and definitions of ‘blackness’. In this regard use is made again of Michel Foucault’s insights and methodology of discourse analysis as shown in The Archaeology of Knowledge (1972). I argue that Oswald Mtshali’s work is a failed attempt at a dissection of apartheid and colonialism from a broadly Christian and humanist perspective. In my reading of Mongane Serote I explore the relationship between women’s bodies and the practice of representation. It is my contention that Serote is most concerned with claims of belonging, and this is shown through his extensive use of the trope of ‘Mother’. My discussion of the poetry of Sipho Sepamla focuses on language and (self- )representation, particularly the use of practices of naming in constructing subjectivity. My contention is that Sepamla ultimately abandons attempts at representation in favour of oppositional self-construction in language. In the concluding chapter I defend the thesis that the politics of discipline have prevented the broad critical establishment from gaining access to these discursive constructions of blackness in the committed poetry of South Africa.
- Full Text:
- Date Issued: 2002
The remote configuration of devices within home entertainment networks
- Authors: Dembovsky, Colin
- Date: 2002
- Subjects: Home entertainment systems , Home video systems
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4685 , http://hdl.handle.net/10962/d1007795 , Home entertainment systems , Home video systems
- Description: This thesis examines home entertainment network remote configuration solutions. It does so by inspecting four home entertainment networking solution specifications - HAVi, Jini, AV/C and UPnP. Two of these (AV/C and UPnP) are implemented partially for a system allowing a TV to configure an AudioNideo Receiver (AV/R) remotely on the network (a process known as remote configuration). The two implementations are then more closely investigated and several implementation differences in the approach between the remote configuration method of device configuration and other methods of device configuration are discerned. These different approaches are then categorised into one of two theoretical models of communication for configuring devices on home entertainment networks - the Rendering model and the Programmed model. By classifying a particular method of device configuration into one of the two models, manufacturers can quickly determine the inherent strengths and weaknesses of that method , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
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From conflict to negotiation: nature-based development on the South African Wild Coast. Special edition
- Authors: Palmer, Robin C G , Timmermans, Herman G , Fay, Derek
- Date: 2002
- Language: English
- Type: Text
- Identifier: vital:543 , http://hdl.handle.net/10962/d1011730
- Description: The Rio Earth Summit of 1992 introduced several new approaches to environmental management under the general heading of sustainable development. One of these approaches has forced conservationists to concede that it is no longer feasible or ethical to exlude resident communities from protected areas, as had been the practice for more than a century. The alternative approach highlighting considerations of social justice and economic empowerment, is to recognise that humans are also part of the local ecology, and to find sustainable ways to maintain local livelihoods along with biodiversity. Especially in the global South, resource-dependant communities associated with protected areas had long been subjected to removals or restrictions by the state, and had been forced to modify livelihoods historically dependant on abundant natural resources, usually resulting in their acute impoverishment. Eastern and Southern Africa had been particulr sites of the former protectionist policies and their frequently tragic sequels for communities. Following the Summit much energy has been expended on finding sustainable alternatives to relocation in these regions, particularly new livelihoods linked to ecotourism From Conflict to Negotiation provides a South African case study of the shift from protectionism to sustainable development in the 1990's. Located on the wild coast of the Eastern Cape, Dwesa-Cwebe consists of a nature and marine reserve with eight adjacent resident communities that have historically depended on local forest, grassland and coastal resources. This are has been the focus of one of the earliest efforts in the 'new' South Africa to restore to the Xhosa-speaking residents ownership of the protected area from which they had been excluded for decades. Unusually the resident initiated the process. While others celebrated the advent of the new democracy in South Africa in 1994, the residents of this remote area, whose grieviences had been ignored during the political transition, planned a protest strategy featuring co-ordinated invasions of the protected area. The protest action succeeded to the extent that it gained massive media attention and provoked the special attention of national and regional goverment, non-govermental organizations (NGOs) and academic researchers. An early academic intervention designed to bring the residents and conservationists together was later expanded. Complementing the roles of goverment and NGOs, environmentalists and socio-cultural anthropologists, among others involved in this project, have attempted to address the conundrum of sustainable development policy implementation in a complex setting. From conflict to Negotiation details the findings of this pioneering research project. It is the story of local empowerment regained as confrontation yielded to negotiation and negotiation yielded co-management, local ownership and developmental partnerships. This landmark study will provoke ongoing discussion and research in an exciting new forum of community development.
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- Date Issued: 2002
Finite element simulations of shear aggregation as a mechanism to form platinum group elements (PGEs) in dyke-like ore bodies
- Authors: Mbandezi, Mxolisi Louis
- Date: 2002
- Subjects: Platinum group , Magmas , Shear flow , Geophysics , Terrestrial heat flow
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5561 , http://hdl.handle.net/10962/d1018249
- Description: This research describes a two-dimensional modelling effort of heat and mass transport in simplified intrusive models of sills and their feeder dykes. These simplified models resembled a complex intrusive system such as the Great Dyke of Zimbabwe. This study investigated the impact of variable geometry to transport processes in two ways. First the time evolution of heat and mass transport during cooling was investigated. Then emphasis was placed on the application of convective scavenging as a mechanism that leads to the formation of minerals of economic interest, in particular the Platinum Group Elements (PGEs). The Navier-Stokes equations employed generated regions of high shear within the magma where we expected enhanced collisions between the immiscible sulphide liquid particles and PGEs. These collisions scavenge PGEs from the primary melt, aggregate and concentrate it to form PGEs enrichment in zero shear zones. The PGEs scavenge; concentrate and 'glue' in zero shear zones in the early history of convection because of viscosity and dispersive pressure (Bagnold effect). The effect of increasing the geometry size enhances scavenging, creates bigger zero shear zones with dilute concentrate of PGEs but you get high shear near the roots of the dyke/sill where the concentration will not be dilute. The time evolution calculations show that increasing the size of the magma chamber results in stronger initial convection currents for large magma models than for small ones. However, convection takes, approximately the same time to cease for both models. The research concludes that the time evolution for convective heat transfer is dependent on the viscosity rather than on geometry size. However, conductive heat transfer to the e-folding temperature was almost six times as long for the large model (M4) than the small one (M2). Variable viscosity as a physical property was applied to models 2 and 4 only. Video animations that simulate the cooling process for these models are enclosed in a CD at the back of this thesis. These simulations provide information with regard to the emplacement history and distribution of PGEs ore bodies. This will assist the reserve estimation and the location of economic minerals.
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- Date Issued: 2002
The distribution of platinum group elements in the Insizwa lobe, Mount Ayliff Complex, South Africa: implications for Ni-Cu-PGE sulfide exploration in the Karoo igneous province
- Authors: Maier, W D , Marsh, Julian S , Barnes, Sarah-Jane , Dodd, D C
- Date: 2002
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150353 , vital:38969 , https://0-doi.org.wam.seals.ac.za/10.2113/gsecongeo.97.6.1293
- Description: The Mount Ayliff Complex of the Eastern Cape province of South Africa is a layered intrusion of some 800 km2 surface area and up to 1,200 m thickness. On the basis of compositional similarities and spatial association, it is generally interpreted to form part of the Karoo igneous province. Similarities between the Mount Ayliff Complex and the staging chambers and feeder conduits to flood basalts that host magmatic sulfide ores elsewhere in the world suggest that the Mount Ayliff Complex may have an enhanced potential for Noril’sk-Talnakh–type massive Ni-Cu sulfide ores, an idea that is supported by the well-known sulfide occurrence at Waterfall Gorge.
- Full Text: false
- Date Issued: 2002
An evaluation of family poultry production systems in the Northern region
- Authors: Ranwedzi, Ndivhuho Emmanuel
- Date: 2002
- Subjects: Poultry -- Breeding , Poultry -- Feeding and feeds
- Language: English
- Type: Thesis , Masters , MTech (Agricultural Management)
- Identifier: vital:10962 , http://hdl.handle.net/10948/93 , Poultry -- Breeding , Poultry -- Feeding and feeds
- Description: Introduction : Family Poultry (FP) are birds of indigenous breeds living in almost symbiotic relationship with human communities. The chickens are usually free ranging, or have very limited restrains on their access to the village environment. African livestock population statistics for 1995 indicates poultry to be the most numerous species of farm animal (Anonymous, 1996a). More than 80% of poultry are kept in rural areas and contribute substantially to annual egg and meat production (Sonaiya, 1997). Throughout Africa poultry production stems from ancient traditional practices. FP is the most important type of poultry kept on the continent. In general, village producers keep small flocks of between 5 and 20 birds per household (Gueye, 1997a). Women and children play a key role in their management (Kitalyi, 1996). Because of its productivity, FP production has been neglected and is frequently considered by farmers as an insignificant occupation compared with other agricultural activities. Nevertheless, outside urban centers and especially in non-coastal areas, FP provides the population with a vital source of protein and income. In addition, they play an important role within the context of many social and/ or religious ceremonies. Although this type of poultry constitutes an important part of food security for rural households in South Africa, scientists have not explored this area of research for improving or recording this production system. Yet, FP survived for decades without being wiped out, in the interim, their keepers have gathered and stored a wealth of knowledge and experience, ensuring the survival of this genetic resource. The objective of this study was to collect the baseline data on FP production systems, determine their production constraints and achieve data for future use in the intervention strategies.
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- Date Issued: 2002
Parasitic Cape bees in the northern regions of South Africa: source of the founder population
- Authors: Neumann, Peter , Radloff, Sarah E , Hepburn, H Randall
- Date: 2002
- Language: English
- Type: text , Article
- Identifier: vital:6908 , http://hdl.handle.net/10962/d1011861
- Description: Multivariate discriminant analyses of nine standard morphometric characters of honeybee workers were used to track the origin of a social parasitic pseudo-clone of thelytokous laying workers that have invaded colonies of Apis mellifera scutellata in South Africa. Twenty social parasitic workers were sampled from both of two infested A. m. scutellata colonies at two distant apiaries (Graskop and Heilbronn, about 390 km apart) and compared with data obtained from 80 colonies in four different geographical zones (zone I: thelytokous A. m. capensis morphocluster; zone II: natural thelytokous hybrids between A. m. capensis and A. m. scutellata; zone III: thelytokous A. m. scutellata morphocluster; zone IV: an arrhenotokous A. m. scutellata morphocluster). Thelytokous laying workers occur naturally in zones I-III. Highly significant morphometric differences were found among the bees in the four zones. The data support the conclusion that the social parasitic workers belong to the thelytokous A. m. capensis morphocluster. It is most likely that the social parasitic workers originated from the heart of the Cape bee's distribution range in the Western Cape region in zone I. Morphometric analysis makes it feasible to restrict the possible origin of the social parasitic workers from the natural distribution range of thelytoky (approximately 240 000 km2) down to about 12 000 km2, which represents a resolution capacity of about 95%.
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- Date Issued: 2002
Detection of neurotransmitters using metallophthalocyanines as electrocatalysts
- Authors: Oni, Joshua Idowu
- Date: 2002
- Subjects: Neurotransmitters Electrochemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4435 , http://hdl.handle.net/10962/d1007470
- Description: Some metallophthalocyanine complexes were synthesized and their catalytic activities towards the detection and quantification of the neurotransmitters dopamine, serotonin and histamine were investigated. The study of the possible interaction between these transmitter substances and the metallophthalocyanine complexes was undertaken. Dopamine, serotonin and histamine formed complexes with Iron (II) tetrasulfophthalocyanine. The rate and equilibrium constants obtained for the coordination are in the range of values reported in the literature for ligand coordination to iron phthalocyanine complexes. Carbon paste electrodes of millimetric diameters modified with Iron (II) tetrasulfophthalocyanine exhibited good electro catalytic activity towards the detection and analysis of dopamine and serotonin while at the same time eliminated the problem of interference posed by ascorbic acid in the electrochemical analysis of neurotransmitters. A detection limit of the order of 10-6 mol dm-3 was obtained for both dopamine and serotonin at the modified electrodes. Carbon paste ultra micro electrodes modified with iron (II) tetrasulfophthalocyanine were also used for the detection of dopamine and serotonin as well as the simultaneous determination of dopamine and ascorbic acid in a mixture. The detection limit obtained for dopamine at the ultra microelectrode was 4.2xlO-7 mol dm-3 The electrode kinetics of vitamin BI as well as the stability of the electrode towards its determination was improved upon by modifying carbon paste electrodes with manganese phthalocyanine. The modified electrodes were used for the analysis of vitamin BI in tablets.
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- Date Issued: 2002
Mandendende vanachiambela
- Authors: Venda boys , Tracey, Andrew T N
- Date: 2002
- Subjects: Venda --(African people) , Folk dancing, Venda , Folk dance music , Sub-Saharan African music , Africa South Africa Venda f-sa
- Language: Venda
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/112134 , vital:33551 , International Library of African Music, Rhodes University, Grahamstown, South Africa , ATC126a-06
- Description: Unaccompanied traditional Venda Tshikona dance song.
- Full Text: false
- Date Issued: 2002
Permaculture as an aspect of environmental learning: an investigation into secondary school communities in Zimbabwe
- Authors: Nyika, Mugove Walter
- Date: 2002
- Subjects: Permaculture -- Study and teaching (Secondary) -- Zimbabwe Land use -- Zimbabwe Land use -- Environmental aspects -- Zimbabwe Agriculture -- Zimbabwe Sustainable agriculture -- Zimbabawe
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1960 , http://hdl.handle.net/10962/d1008447
- Description: The Schools and Colleges Permaculture (SCOPE) Programme in Zimbabwe has developed a process for use by schools in planning for the sustainable management of their land. The process is called Integrated Land-Use Design (ILUD) and is based on Permaculture principles. The ILUD process has so far been implemented in 54 pilot schools where it has been used to facilitate the re-design of the school grounds through the active participation of the students, staff and parents. The aim of this research was to investigate what environmental learning takes place during the implementation of the ILUD process and related activities, with a view to informing the improvement of the process. The research was conducted within the interpretive paradigm with particular use being made of the Symbolic Interactionist theoretical framework to explore the social situations in which the ILUD process has been applied. A purposive sample of two schools and five form 4 (grade 11) pupils from each school was selected for the study. The main data collection method was the structured interview. Other data were collected from nonparticipant observations and the analysis of documents, particularly photographs. The data was analysed using the constant comparative method. The findings point towards a significant contribution from the Permaculture activities to the environmental knowledge, environmental management skills and the positive environmental attitudes of the pupils. The work done at the two schools indicates the usefulness of the ILUD process as a tool for environmental action in the schools but its application in the communities was found to be limited by constraints such as lack of resources and the limited capacity of teachers to work in the field of adult education and training. It is recommended that Permaculture should be integrated into the secondary school curriculum if the momentum of the progress made so far is to be maintained. The SCOPE Programme itself needs to be strengthened for its work with communities. There is, for example, a need for adult education and training methods if the introduction of ILUD to the communities is to be successful.
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- Date Issued: 2002
The development of effective promotional strategies to market public FET/Technical Colleges in the Eastern Cape Province
- Authors: Gaika, Nandipha Gloria
- Date: 2002
- Subjects: Universities and colleges -- South Africa -- Business Management , Marketing research -- South Africa
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10940 , http://hdl.handle.net/10948/d1006191 , Universities and colleges -- South Africa -- Business Management , Marketing research -- South Africa
- Description: Education is a powerful and pervasive agent of change. Therefore, it is the key to unlock the doors to development and modernisation. Currently, business and communities knowledge very little about what the FET/Technical College is offering and its importance to the society as whole. Therefore there is a great need to market the technical sector so that the community is knowledgeable about the FET/Technical Colleges. The research conducted focuses on which promotional strategies are effective in marketing the FET Colleges. In order to make technical college students marketable it is necessary to market the institutions effectively so that all the stakeholders can be aware of what technical colleges can offer. Because of high competition in this industry, it is of vital importance not to be out-marketed by competitors by keeping abreast of new trends in promotional strategies. In order to obtain more relevant information about promotional strategies a literature study was conducted to develop a questionnaire to survey the importance of promotional strategies and determine which promotional strategies are being used by the FET Colleges. The East-London, Queenstown and Ezibeleni Public FET Colleges form the respondents. From each college five academic staff, two management members and five students formed the respondents. Community members, business community members, the Department of Education and the Department of Labour representatives were also included in the sample from each of the selected FET Colleges. The findings of the survey revealed the high level of agreement in terms of the importance of the promotional strategies identified in the literature study with the exception of some promotional strategies, which were identified as not compatible with the FET target market. The study recommended that further research be done on a larger sample size focusing on particular stakeholders eg. students of the FET Colleges in a specific area.
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- Date Issued: 2002
Reproductive conflicts in honeybee colonies
- Authors: Pirk, Christian Walter Werner
- Date: 2002
- Subjects: Honeybee -- Reproduction
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5755 , http://hdl.handle.net/10962/d1005443
- Description: In advanced eusocial hymenopteran societies workers have ovaries and can lay eggs, but are unable to mate. Workers are more related to their own offspring than to every other member of the colony. So worker reproduction contains both worker-worker and worker-queen conflict. The queen- worker conflict is discussed elsewhere, but if the queen mates with more than two males, worker policing should be selected to lower potential conflicts. However in the Cape honeybee it was predicted that worker policing is absent or less expressed than in other honeybee subspecies, because workers produce female offspring thelytokously. So laying workers and their offspring are nearly genetically identical, which results in the fact that other workers are as related to workers derived from eggs laid by the queen as laid by a worker. However, worker reproduction may be costly and therefore worker policing could be an evolutionary adaptation in the Cape honeybee to lower the costs derived from laying worker activity. Indeed, Cape honeybee colonies show efficient egg removal behaviour, suggesting that other factors like colony efficiency could favour egg removal behaviour. Since egg removal behaviour is a colony phenomenon, factors that affect colony performance could also affect egg removal behaviour. Egg removal behaviour was considerably affected by environmental changes, indicating that other tasks have a higher priority than egg removal behaviour. Thousands of queenright colonies of the neighbouring subspecies (A. m. scutellata) were taken over by laying A. m. capensis workers, showing that A. m. capensis workers are facultative social parasites. These observations strongly indicate that laying workers of A. m. capensis are able to evade worker policing and the inhibitory effects of the queen pheromones, but what potential strategies could these laying workers use to increase the survival of their eggs and evade the queen? On the one hand, egg removal behaviour is variable. One behavioural strategy of laying workers to achieve successful reproduction could be that they lay during periods with low egg removal behaviour. On the other hand, the inhibitory effect of the queen’s pheromones diminishes with distance. Maybe the level of egg removal also depends, like the inhibitory effect of the queen pheromones, on the distance from the queen. Indeed, further away from the queen the effect of the queen pheromone and the level of egg removal is reduced, making successful worker reproduction possible. In both subspecies, A. m. capensis and A. m. scutellata, egg removal behaviour is reduced further away from the queen. In the case of A. m. scutellata egg removal is lacking further away from the queen. This explains why colonies of scutellata are so prone to takeovers by laying Cape honeybee workers. One question in the context of parasitic Cape honeybees is how they manage to get into the host colony. One way could be that they get into the colonies during a natural colony merger which is common in African bees. Two unrelated colonies merged and it took them only 24 hours to show effective integration. Because both colonies are unrelated, the potential reproductive conflict among workers should be more strongly expressed than in a normal colony, which is not the result of a merger. Therefore, the effect of nestmate recognition for eggs on the egg removal behaviour was investigated. The results suggest that workers recognise the origin of an egg and that the standard policing experiments overestimate the level of egg removal and only represent relative values. Moreover, the results show that colony specific components on the eggs are more important than a postulated queen egg marking pheromone. Finally, for the first time empirical evidence from a population of the parasitic laying Cape honeybee workers, invading thousands of colonies of A. m. scutellata in northern South Africa, for a short-sighted selection theory is presented.
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- Date Issued: 2002
The development of a model on which to base franchise relationships
- Authors: Kirabira, Godfrey
- Date: 2002
- Subjects: Franchises (Retail trade) -- South Africa , Franchises (Retail trade) -- Law and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10920 , http://hdl.handle.net/10948/85 , Franchises (Retail trade) -- South Africa , Franchises (Retail trade) -- Law and legislation -- South Africa
- Description: This paper aims at developing a model on which to base good quality franchise relationships. The franchise sector has the potential to generate wealth for the franchisee and the franchisor, create employment and be a tool of empowerment. It is also associated with relatively less risk than other forms of self-employment. However, there have been a disturbing number of failures in the sector and reported cases of abuses of franchisees by franchisors. Some franchisors have sought liquidation of franchise units in courts of law. An investigation was commissioned into the sector with the objective of uncovering problems in the quality of the relationships in the sector. The obligations of both the franchisees and franchisors were stipulated. Aspects of quality were then considered to lay a foundation upon which improvements in the relationships could be based. This was followed by a survey to find the performance gap between the quality of service that was expected from the franchisor and what the franchisees were actually receiving. Five dimensions of service quality – tangibles, reliability, responsiveness, assurance and empathy were empirically investigated. The findings of this research revealed that the quality of service of franchisors fell short in all dimensions. It is arguable that other aspects of quality are being neglected by the franchisors. It is against this backdrop that a model is proposed to improve the quality of service in the franchise relationships. The model incorporates contemporary ideas on quality. Principles of total quality management, quality function deployment, customer satisfaction and self-assessment are applied to the franchise relationship. The use of the model will contribute towards better relationships in the franchise sector.
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- Date Issued: 2002
Biological sulphide oxidation in heterotrophic environments
- Authors: Rein, Neil Berthold
- Date: 2002
- Subjects: Acid mine drainage , Oxidation , Sulfides , Oxidation, Physiological
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3919 , http://hdl.handle.net/10962/d1003978 , Acid mine drainage , Oxidation , Sulfides , Oxidation, Physiological
- Description: Acid mine drainage is a major environmental pollution concern associated with the mining of sulphide-containing ore bodies. Both physicochemical and biological options have been investigated for the treatment of acid mine drainage with recent interest in biological processes targeting low-cost and passive treatment applications. All acid mine drainage biological treatment processes are based to some extent on the activity of sulphate reducing bacteria, and their ability to reduce sulphate to sulphide in the presence of a range of carbon and electron donor sources. A portion of the sulphide produced may be consumed in the precipitation of heavy metals present in the mine drainage. Residual sulphide must be removed, not only due to its toxicity, but especially to prevent its reoxidation to sulphate where salinity reduction is a target of the treatment process. The partial oxidation of sulphide to elemental sulphur is an option that has received considerable attention and both physicochemical and biological options have been investigated. Biological processes have substantial potential cost advantages and run at ambient temperatures and pressures. However, the oxidation of sulphide to elemental sulphur is poised over a narrow redox range and process control to maintain optimum conditions remains a serious problem. In addition little has been reported in the literature on process control of sulphide oxidation to elemental sulphur, in the heterotrophic conditions prevailing in the reaction environment following sulphate reduction. This study undertook an investigation of biological sulphide oxidation under heterotrophic conditions in order to establish the effect of organic compounds on biological sulphide oxidation, and to determine whether the presence of organics, and associated heterotrophic oxygen consumption, may be manipulated to maintain the defined redox conditions required for the production of elemental sulphur. Biological sulphide oxidation under heterotrophic conditions was investigated in a series of flask experiments. Based on these results three different reactor configurations, a Fixed-Film Trickle Filter Reactor, Submerged Fixed-Film Reactor and a Silicone Tubular Reactor were used to investigate sulphur production. The flask studies indicated that organics, and associated heterotrophic metabolism in the presence of excess oxygen in the sulphide oxidation reaction environment, did contribute to the poising of redox conditions and thereby enabling the production of elemental sulphur. While the Fixed-Film Trickle Filter Reactor was found to be redox unstable, probably due to excess oxygen ingress to the system, a reduced oxygen challenge in the Submerged Fixed-Film Reactor configuration was found to be more successful for production of elemental sulphur. However, due to the production of a predominantly filamentous sulphur producing microbial population, recovery of sulphur from the column was intermittent and unpredictable. Extended residence times for produced sulphur on the column increased the likelihood for its eventual oxidation to sulphate. The Silicone Tubular Reactor was found to support a vigorous sulphide oxidising biofilm and produced elemental sulphur effectively. Electron microscopic studies showed that this occurred as both biologically produced sulphur and, probably mainly, as crystalline sulphur in the ortho-rhomic form. Given the linear extension of the sulphur production reaction environment it is was possible to investigate the sequence of the reaction mechanism in grater detail than is possible in mixed systems. Based on these findings a model explaining sulphur production under heterotrophic conditions has been proposed and is presented. The commercial implications of the development have also been noted.
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- Date Issued: 2002
Tshikona
- Authors: Venda men and boys , Tracey, Andrew T N
- Date: 2002
- Subjects: Venda --(African people) , Folk dancing, Venda , Reed pipes (Organ pipes) , Drum , Instrumental music , Sub-Saharan African music , Africa South Africa Venda f-sa
- Language: Venda
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/112116 , vital:33549 , International Library of African Music, Rhodes University, Grahamstown, South Africa , ATC126a-04
- Description: Instrumental Venda Tshikona reed pipe dance music with close up on individual pipes
- Full Text: false
- Date Issued: 2002
An investigation of the effects of leadership training on junior managements' (sic) morale at three manufacturing organisations within the Buffalo City Area
- Authors: Naina, Ruweida Anastacia
- Date: 2002
- Subjects: Employee morale , Leadership
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10908 , http://hdl.handle.net/10948/105 , Employee morale , Leadership
- Description: The present study was undertaken to determine the effects that leadership training has on employees’ morale at work. The study was conducted on 15 students from three organisations within the Buffalo City area, studying towards a Diploma in Manufacturing Management at the Johnson & Johnson Leadership Development Institute, Rhodes University, East London Campus. The main aims of the study were: · to review the literature of the leadership training conducted at the Johnson & Johnson Leadership Development Institute (JJLDI), and to assess the effects it has on employees’ morale at work. · to provide industry with documented evidence that the leadership training conducted at the JJLDI has a positive influence on employees morale. · to provide the JJLDI with valuable information as to whether or not the course material and methods has a positive impact on meeting industry demands. A secondary objective of the study was to provide a medium in which students undergoing the leadership training were able to address their concerns with regard to course content and structure. Fieldwork comprised a 5-day, week (40 hours) of intensive lectures and group discussions at Rhodes University. Students were then assigned a 4-month workbased project with the lecturer acting as mentor to each student. The researcher used self- administered electronic questionnaires as the research tool. Results revealed the following: · that the students morale increased by more than 20 percent after having undergone leadership training; that the students communication skills has increased, and, · that the students interpersonal relations with co-workers has shown a significant increase Future implications are that students exposed to this type of leadership training will have a positive influence on their co-workers. This will spurn a new organisational culture that will cope with global demands. In some cases these future leaders will be the source of sustained competitive advantage over insurgents through increasing the organisation’s human, social and knowledge capital.
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- Date Issued: 2002