A project report submitted to the Faculty of Engineering, in partial fulfilment of the requirements for the degree of Master of Science in Engineering, University of the Witwatersrand. Johannesburg 1990. / Robotics are becoming a more prominent force in the industrial environment, and research is being concentrated on control rather than on the robot. The feasibility of a substitute, off-line, plc based control system was investigated. Many advantages are associated with an off-line system, as well as the large financial saving (at the most 50% that of the existing controller) . A PLC with discrete 1/0 modules and a fast counting module were used. Open loop control was looked at, with optical encoders used for position control. Overshoot of the DC motors consistently occurred, and other external factors ensured the unpredictability and instability of open loop control. It was concluded that closed loop control was necessary to ensure accurate positioning and speed control. PLC modules Were investigated, and an axis control system (not yet commercially available) was found to ideally suit the purpose of servo/encoder control. This system makes use of speed and position feedback signals, essential for accurate terminal Control of the robot. / MT2017

The purpose of the research was to develop a translucent low fired porcelain casting slip using South African raw materials, due to the ever increasing electricity tariffs in South Africa as well as the physical deterioration put on the elements and brickwork in electric kilns when fired to traditional porcelain temperatures. Traditional porcelain bodies that can be purchased from South African suppliers are required to be fired to between 12000C and 13000C. The commercially prepared porcelains when tested produced white vitrified bodies but were lacking in translucency. Local ceramic artists are therefore compelled to import their porcelains from overseas suppliers if they require a white translucent porcelain but this is still requires a firing temperature well above 12000C. It has been shown that by using South African ceramic raw materials and adjusting a Parian ceramic formula using a selected frit; a low fired translucent porcelain can be made that matures below 12000C. The addition of paper fibres to the non-plastic porcelain was necessary to reduce the high shrinkage rate and prevented the clay from cracking and tearing in the firing process. With the further adjustments to the formula by the addition of calcium triphosphate true white translucent porcelain was produced. Without this last adjustment the porcelain would be an off-white colour due to the impurities found in the South African ceramic raw materials which are mainly contaminated with iron oxide. It was found that the following formula produced a white translucent porcelain which vitrified at 11900C and satisfies the original concept in the title stated above.

Thesis presented for the Degree of Doctor of Philosophy at the University of the Witwatersrand / Successional changes in the vegetation after fire were studied in several fynbos communities of the south-western Cape Province of South Africa. The study sites were located in the mountains, at altitudes between 300 and 1000 m a.s.l., in areas with winter rainfall regimes -1 and annual precipitation of about 900 to 1000 mm. yr Soils are highly leached, derived principally from quartzites. The two main sites were Zachariashoek near Paarl, where summers tend to be rather dry, and Jakkalsrivier east of Grabouw, where summer drought is ameliorated by fog precipitation and cloudiness. Successional changes were followed for intervals of up to 10 yr between fires, as well as for similar periods in vegetation that had been unburnt for 25 yr. Vegetational changes were analysed by means of repeated floristic assessments on permanent quadrats and point-quadrat sampling of canopy cover composition on these and on larger plots. At Jakkalsrivier, recently burnt and long unburnt vegetation were also compared by paired samples. Demographic trends in populations of prominent shrub species were followed by repeated censuses of tagged samples in unburnt and recently burnt vegetation. Also at Jakkalsrivier, the effects of fire on resources available to plants were examined by sampling soil moisture and soil mineral nutrients, as well as by following trends in xylem pressure potentials in selected species of plants and analysing their foliar nutrient concentrations. Effects of fire on microclimate were tested by comparative studies on burnt and unburnt sites. All fynbos communities sampled proved to be highly stable in the face of fire. Essentially, the pre-fire species composition was regained in 2-3 yr in every case. Species were added after fire, partly because of the appearance of ephemerals with life histories tied to fire, but also because of the reappearance of longer-lived plants as well as through the readier detection of species in vigorous vegetative form. The species richness of the regenerating corrununities tended to be quadratically related to pre-fire biomass, as predicted from current succession theory. Most species in any corrununity (about 70% on average) regenerated vegetatively by sprouting after fire. The relative numbers of species that regenerated germinatively, i.e. the seeders, did not vary in a manner predictively related to corrununity biomass. There were relatively few species with specialised life histories based on reseeding, such as those with canopy-stored seed and ephemerals with presumably specialised requirements for germination. Virtually no recruitment could be found among plants in the older (about 25 yr) vegetation, in contrast with lowland fynbos sites, where recruitment of herbaceous species occurs, and some mountain fynbos sites on more fertile soils, where forest precursors may sometimes colonise. Canopy redevelopment after fire indicated similar resilience among the different corrununities, despite variation in regrowth rates. Pre-fire growth-form composition was restored within around 10 yr. Maximum leaf-area indices ranged from about 1,5 to 2,5, although corrununi ties on phreatic sites had leaf-area indices exceeding 3,0. There was no evidence for a suppression of the understoreys by overstorey layers, mainly because the latter were sparse despite the abundance of tall broad-sclerophyllous shrubs in certain habitats. This was because the taller shrubs had sparse or slender crowns, or both, and because mortality tended to thin the populations before dense canopies developed. Trends in the composition of the canopy varied among corrununities. corrununities in productive habitats, i.e. in this case on phreatic sites, were dominated in the early stages by a relatively luxurious growth of ephemeral herbs and soft shrubs which declined within around 3-4 yr. Other sites had very sparse ephemeral cover, the early stages being dominated mainly by Restionaceae, Cyperaceae, and other sprouting herbs, and sprouting and seeding shrubs, which were constituents of the pre-fire canopies. In this respect, the fynbos is clearly distinguished from the California chaparral, for example, where ephemerals tend to dominate the post-fire stages on most sites. There was no evidence that fire had any effect on the water relations of regenerating vegetation, although stream discharge is known to be increased by fire in these environments. There was tentative evidence, in enhanced foliar concentrations of some mineral nutrients, that regenerating species of climax plants exploited nutrients released in fire. However, any such responses were small, especially in comparsion with responses observed in chaparral, for example. Ephemeral shrubs had much higher concentrations of foliar nutrients overall than climax species, tending to confirm the correlations found in Australian heathlands between plant life-history and nutrient economy. The effects of fire on microclimate were pronounced, especially on the thermal and water vapour regimes experienced by seedlings and sprouts. These extremes did not, however, appear as water stress in regenerating plants. Despite relatively sparse canopies, mature vegetation did reduce light at the ground to levels likely to affect seedling recruitment and survival. Preliminary experiments with a local dominant shrub, Leucadendron xanthoconus, showed a pronounced intolerance of shading and hence that light attenuation by canopies must be implicated in successional processes. The demographic studies indicated that density-dependent effects were not important in survival of plants. Two species of fire ephemeral shrubs effectively died out within four years, being characterised by markedly higher growth rates than climax species and brief and early fecundities. Climax shrubs had more or less constant rates of mortality over time, though populations in unburnt vegetation tended to have slightly higher rates of mortality than young populations. Densities of seedling populations were very high, but mortality rates were extremely low. In summary, it may be said that the fynbos communi ties studied here are very stable under a given fire regime. Recovery is rather rapid, being apparently achieved within 10 yr. Not much change occurs in older vegetation, but there was a gradual attrition of populations of dominant shrubs, without recruitment, with rare exceptions. Summer droughts in these montane environments are evidently not sufficiently marked for water deficits to play a primary role in succession, so that fire has no effect on plant water relations. Nutrient responses are relatively weak, and masked in the plants by the low rates of metabolism in climax species. Succession after fire is distinguished by the recovery of pre-fire communities, and subsequent inhibition of recruitment. This inhibition is probably through the effects of canopies on microclimate, although the interactions between especially plants and animals have been implicated in succession in other studies. / AC2017

Thesis (DTech (Public Management))--Cape Peninsula University of Technology, 2007 / Since 1992 the National Research Foundation and the Department of Trade and Industry, with support from industry, have been running a funding initiative under the auspices of Technology for Human Resources in Industry Programme (THRIP). This initiative provides funding to qualifying academics/researchers in South Africa's tertiary institutions and science councils to conduct research and development-oriented (or applied) research. This collaborative funding of applied research is geared to facilitating cross-transference of knowledge, skills and resources across academic institutions, government science, engineering, technology institutions and the industrial sector. It is also expected that research and project outputs will be commercialised to improve the competitiveness of South African industry in the face of globalisation and technological advancement. With public money spent on research projects of national importance, impact and value for money become Vitally important, hence the need for impact assessment. A non-probabilistic sample of 52 research projects in seven standard industrial classification categories or sectors conducted by 44 project leaders (who are academics/researchers) based in seven traditional universities, one former technikon (now university of technology) and three divisions of the Council for Scientific and Industrial Research, were assessed for impact. A non-experimental design was used, involving synergising the goal-attainment and side-effects evaluation models, and reinforcing them with two elements of causal tracing, temporal precedence and coherence, to facilitate attribution of benefits and impacts. THRIP's strategic objectives served as relevant indicators for impact assessment since projects' objectives co-terminate with them. In the context of the research, a definition of 'performance indicator' as "evidence of what has actually happened" was adopted, lending weight to project leaders' reports of projects' impacts. 'Success', defined in terms of projects' not only accomplishing their objectives, but also yielding value to beneficiaries and stakeholders, is posited as a possibly problematic term given that different stakeholders might have different criteria of judging it. Responses obtained from questionnaires administered to project leaders and industry partners' or sponsors' contact persons, the latter for triangulation, were analysed and categorised into four broad thematic areas: human resource development/intellectual, commercial/economic, social and technological. A number of findings emerged from the main questionnaire. A little more than half (56%) of the projects were completed and 44% were ongoing; majority (85%) were implemented according to plan; three categories of primary beneficiaries were cited by project leaders; projects were meant to address multiple problems/situations; they had multiple objectives; and majority (92%) were successful and made many impacts. Managerial strategies, supplemented by environmental and other factors, contributed to projects' success. Several reasons were offered for failure or inconclusiveness.

M.A. / The relatively rapid development of biological approaches to various psychological conditions, has prompted clinicians and researchers to investigate Borderline Personality Disorder more thoroughly. Research has evidenced the uniqueness of Borderline Personality Disorder in terms of description, aetiology and treatment. Of the various aetiologies proposed, the neuropsychological deficit approach is one which is still in its infancy and which may have promise for new treatment strategies. Latest developments delineate neuropsychological deficits in the areas of memory, perception and visuospatial ability. These factors are important for psychotherapeutic purposes. The purpose of this study was to further existing knowledge as regards the aetiology of Borderline Personality Disorder in order to initiate new treatment modalities and management strategies. The study examined whether a battery of neuropsychological tests could detect organic dysfunction in the areas of construction, orientation and attention, memory, perception and concept formation and reasoning in twenty inpatients diagnosed according to DSM-IV criteria, with Borderline Personality Disorder. Two control groups were used, one comprising twenty inpatients diagnosed according to DSM-IV criteria with Personality Disorders from Axis II, Clusters A or C; and the other comprising twenty normal volunteers. Neuropsychological functioning assessed, included measures of attention, construction, visual and auditory-verbal memory, perception, and concept-formation and reasoning. Measurement instruments used in this study included the Digit Symbol subtest of the WAIS-R; Rey Complex Figure; Logical Memory subtest of the WMS-R, Gottschaldt Embedded Figures Test; and the Wisconsin Card Sorting Test. (v) Analysis of variance, multivariate analysis of variance and post hoc tests revealed significant deficits in neuropsychological performance among the borderline personality disorder group and the control group of other personality disorders but not the normal volunteer group. Dysfunction was particularly significant in the areas of attention, visuospatial ability, perceptual organization, and ability to maintain cognitive set. These deficits do not appear to have been attributable to attention deficit disorder, attention deficit hyperactivity disorder, temporal lobe epilepsy, head injury, a concurrent Axis I diagnosis such as major depressive disorder, or current drug and/or alcohol abuse. The observed deficits suggest new ways of understanding the development and maintenance of Borderline Personality Disorder, and provide indications for treatment. In conclusion, it is recommended that full use be made of the measurement instruments used in this study as diagnostic aids to enhance the effectiveness of treatment modalities. It is further recommended that research in this topic be repeated and extended using a larger sample and matched controls.

M.A. (Psychology) / This study set out to try and find some answers to questions pertaining to psychotherapy groups in the admissions ward of a psychiatric hospital. The questions were about the effect of group therapy on: * the system of the psychiatric hospital; * the therapists within the system of the psychiatric hospital; * the members of the groups (the patients). * which prosesses took place within the group therapy that can be regarded as therapeutic, and * which prosesses can be described as anti-therapeutic and destructive? The study is descriptive in nature and looks in turn to group therapy in the context of the psychiatric hospital and the efforts of two clinical psychology interns to run therapy groups in the admissions ward of a psychiatric hospital. The conclusion is made that the effectiveness of group therapy in a psychiatric hospital is limited as long as the epistemological differences between psychiatry and psychology are not attended to and as long as the status of psychologists in general, and interns in particular, stays as it is at present. With this in mind, recommendations are made regarding the context, organisation, goals and structure of group therapy as well as the role of the therapist, training of interns in group therapy and further research.

M.Sc. / The tribe Podalyrieae is a group of Papilionoid legumes that are largely endemic to the Cape Floristic Region of southern Africa. A phylogenetic study of the tribe was undertaken using gene sequences obtained from the internal transcribed spacer (ITS) as well as the plastid gene rbcL. Although the resolution was poor in the resulting trees, several groupings were noted within the tribe. The subtribe Xiphothecinae remains relatively unchanged and consists of the genera Amphithalea and Xiphotheca. The subtribe Podalyriinae was found to be paraphyletic. A close relationship was observed between the genera Liparia and Podalyria with Stirtonanthus as sister. Additional chloroplast genes (trnL-F and trnS-trnG) were sequenced to obtain better resolution within this group. While Podalyria and Stirtonanthus are monophyletic, the monophyly of Liparia is still uncertain. Virgilia and Calpurnia are closely related and Cyclopia retains its isolated, monophyletic position sister to the tribe. The species of Cadia included in the phylogenetic analysis formed a sister grouping to the tribe Podalyrieae and the inclusion of this genus in Podalyrieae is discussed. A date for the root node of the tribe was estimated at 28.55 MYA, using non-parametric rate smoothing (NPRS), indicating a major radiation to have taken place during the Pliocene. By means of independent contrasts it was determined that the rate of molecular evolution is higher in reseeders than resprouters, perhaps due to more reproductive cycles in these individuals, that would in turn affect the rate of DNA substitution.

Ph.D. / Genetic variation estimates and phylogenetic studies (based on genetic differentiation) of the Podalyrieae and related tribes (family Fabaceae) are presented. The tribe is endemic to the Cape fynbos region of South Africa, except for Calpurnia. Although Podalyrieae have been the focus of many taxonomic studies no genetic variation studies have been done on this group of plants. Genetic variation in selected populations, species and genera was studied to evaluate the use of enzyme electrophoresis in systematic studies on these three levels. Eight case studies are presented. Allelic data proved to be extremely useful at the population and congeneric species level. However, at a higher level, it showed some potential when treated with caution. It is not possible to predict beforehand if meaningful results can be obtained at this higher (i.e. confamilial genus) level of divergence. A large number of plant genetic data sets from the literature was analysed to determine typical levels and ranges of genetic differentiation within families, genera and species. A graph of probability against taxonomic rank was constructed and compared with results published by Thorpe (1982, 1983). The results indicate that plant taxa have a reduced biochemical evolution (less diverse than animals at comparable taxonomic ranks) in contrast to Thorpe's (1982, 1983) reports (which were based on less data for plant taxa). Genetic identity values between 3041 pairs of taxa were used in the present study. The phylogenetic relationships among genera of the tribe Podalyrieae were estimated from sequences of the internal transcribed spacer (ITS) region of nuclear ribosomal DNA as well as morphological and chemical data. Morphological and. ITS sequence data produced cladograms with similar topologies, both supporting the exclusion of Hypocalyptus from Podalyrieae. A broadening of Podalyrieae, which includes Xiphothecinae, Podalyriinae and Cyclopia, is suggested. The multidisciplinary approach followed in this study provided a better understanding of taxonomic and evolutionary relationships in the Podalyrieae and some other Cape legumes.

M.Sc. / The current study sought to investigate the relationship between stress and illness, while examining the effects of daily stressors, depression, hardiness, social support and coping skills on this relationship. The information gathered was then used to design a time and cost effective questionnaire to predict people prone to stress-related illness. This questionnaire has been called the Stress Fitness Scale. The subjects (n = 44) were split into three groups (healthy, ill, and neither ill nor healthy) according to their scores on Gurin's Psychosomatic Symptom List for non-parametric statistical analysis. Scores on the Hardiness Scale, Perceived Social Support Friends and Family, Beck Depression Inventory, COPE, Hassles and Uplifts Scale and Life Experiences were analysed and significant differences were found between the ill and healthy groups in all five areas using a Mann-Whitney U test. An intercorrelation matrix was performed and significant correlation was found between Stress Fitness and the other scales, although not for all the sub-scales. Many of these correlations corresponded with the differences found between the two groups using the Mann-Whitney U test. Item analysis was performed on the Stress Fitness Scale. Significant inter correlation was found for all the items of the Prone sub-scale, and all but three items of the Protect sub-scale. Although further research is necessary, from this limited study the Stress Fitness Scale appears to provide a time and cost effective way of predicting people prone to stress-related illness.

During the period April 1994 and February 1996 as part of an investigation into the national Iinefishery, the east coast shore fishery and the recreational and commercial ski-boat fisheries were surveyed, at eight sites between Kei Mouth in the East and Stil Bay in the West. Roving creel, access point and aerial surveys were used. A questionnaire was developed for each sector to gather data on catch and effort, fisher demographics, economics, fisher attitudes towards, and knowledge of, the current management regulations and assess the efficacy of the fisheries inspectorate. During the access point survey the catch of 3273 fishers was inspected and 1556 interviews were conducted. Questionnaires were conducted on 118 recreational ski-boaters and the catch of 165 boats was inspected. 96 commercial skippers were interviewed and 230 had their catch inspected. Three aerial surveys of the entire area were conducted during which a total of 1067 shore fishers were counted giving a shore fisher density of 0.39 fishers.km⁻¹. The majority (99%) of participants in all sectors of the linefishery were male. The greatest number of participants were white, shore fishery 77% recreational ski-boat 98% commercial skiboat 89%, followed by coloured, asian and black people. To a large extent this reflects the income of various racial groups. Most fishers supported the current linefish management plan. However, when tested on their knowledge of the size limits, bag limits and closed seasons of their target species many shore fishers (59%) did not know them and a high proportion of fishers in all sectors had disobeyed at least one of the regulations (shore 50%, recreational ski-boat 70%, commercial ski-boat 56%). When compared to historical data the present catch per unit effort (CPUE) in all sectors has decreased. Most interviewees in the various sectors did not accept responsibility for the decline in CPUE, but attributed it to three principal reasons vis their perceived direct competitors, trawling and pollution. Analysis of the catch revealed that all sectors were multispecies fisheries, with each sector being characterised by a small number of target species. Catch composition differed significantly between the shore and ski-boat sectors, but there was significant overlap between the two skiboat sectors. Analysis of the catch in comparison to that reported to the National Marine Linefish System (NMLS) revealed that there was a substantial degree of under-reporting. There was little seasonal difference in effort in the shore fishery while the recreational ski-boat effort was highest in the summer and the commercial ski-boat effort was high in the winter. Effort in the shore and recreational ski-boat fisheries was concentrated over weekends while the commercial ski-boat effort was highest during weekdays. Total effort for the entire area was estimated at 903 186 (±1913) fisher days per annum in the shore fishery, 24 357 (±685) recreational ski-boat fisher days and 64 266 (±1686) commercial ski-boat fisher days. Expenditure and capital investment in the various sectors was calculated, as were earnings of the participants in the commercial ski-boat sector. The linefishery in the Eastern Cape was estimated to have a minimum capital investment in excess of R210 million and more than R32 million is spent annually on running costs. The commercial ski-boat fishery directly employed an estimated 3184 people. The economic implications of changes in CPUE for the commercial ski-boat fishery are considered, as are the benefits of a recreational angling licence. Management of the linefishery is discussed in relation to the findings of this study.