Thesis (Ph. D.)--University of Hawaii, 1992. / Includes bibliographical references (leaves 352-368).

Thesis (Ph. D.)--University of California, Berkeley, 1993. / Includes bibliographical references (leaves 667-680).

Thesis (M. Tech.) - Central University of Technology, Free State, 2008 / A company’s ability to produce products faster and more economically may lead to a competitive edge in the international market. The reduction of development costs and shortened development time will undeniably depend on effective organisational structures that are based on effective information- and communication techniques and manufacturing technologies. An innovative manufacturing technology that impacts on rapid product development is Rapid Prototyping (RP). The Centre for Rapid Prototyping and Manufacturing (CRPM) works closely with South African companies, supporting them with common mechanical engineering solutions and specialising in the manufacturing of prototypes. One of the options offered in the manufacture of prototypes is the Laser Sintering (LS) process. It is however, difficult to determine the product cost for the building volume used to manufacture the prototypes. Prototypes from different clients can be manufactured at the same time in the same process. The problem however, is how to calculate the costs for each prototype and to offer the clients an accurate quotation for the manufacture of the prototype. Therefore, it is necessary to design a calculation concept, which includes all accrued costs and allocate these to the different parts/prototypes. As it is problematic to calculate the manufacturing cost of prototypes, it is necessary to analyse all the effects, parameters and influences on the manufacturing process in order to determine the manufacturing time, and ultimately the machine costs. This is needed to calculate the total cost of one platform and the cost of each individual part. The project, through various experiments determined how to allocate the costs, through a correlation between part volume and platform height. The aim of the study was to determine a calculation concept to estimate the total platform cost and the cost of each individual part. Furthermore, the estimated cost was compared with the actual cost to determine the deviation between the calculation methods, and lead to a calculation concept that can be used to predict and reduce the manufacturing costs. The results obtained from the research were used for an exact calculation and reduction of prototype unit costs manufactured on LS machines, which gave three basic advantages: * Manufacturing costs were reduced to benefit clients, which meant that they could invest more in the design of new prototypes and products, to improve customer satisfaction * Prototype manufacturing on expensive RP machines could be optimised by using more prototypes and lower costs for entering the market. * The calculation risk could be minimised, which lowered the risk of losing money on a project and resulted in better planning for available resources.

Thesis (M. Tech.) -- Central University of Technology, Free State, 2010 / The latest technological trend in manufacturing worldwide is automation. Reducing human labour by using robots to do the work is purely a business decision. The reasons for automating a plant include: Improving productivity Reducing labour and equipment costs Reducing product damage Monitoring system reliability Improving plant safety. The use of robots in the automation sector adds value to the production line because of their versatility. They can be programmed to follow specific paths when moving material from one point to another and their biggest advantage is that they can operate for twenty-four hours a day while delivering consistent quality and accuracy. Vision-Guided Robots (VGRs) are developed for many different applications and therefore many different combinations of VGR systems are available. All VGRs are equipped with vision sensors which are used to locate and inspect various objects. In this study a robot and a vision system were combined for a pick-and-place application. Research was done on the design of a robot for locating, inspecting and picking selected components from a moving conveyor system.

Thesis (M. Tech. (Civil engineering)) - Central University of Technology, free State, 2013 / Hydrological models have become vital tools for understanding hydrologic processes at the catchment level. In order to use model outputs for tasks ranging from regulation to research, models should be scientifically sound, robust, and tenable. Model evaluation is therefore beneficial in the acceptance of models to support scientific research and to guide policy, regulatory, and management decision-making. The objective of this study was to evaluate the performance of the SWAT model in simulating stream flow for the Modder River Basin. The study area is situated at -29° 11’ latitude and 26° 6’ longitude at an elevation of 1335 m and drains a land area of 949 km2. The land cover is mainly grassland (pasture) with other minor land use types. The climate of the area is semi-arid with Mean Annual Precipitation (MAP) of 563 mm. Two techniques that are widely used in evaluating models, namely quantitative statistics and graphical techniques, were applied to evaluate the performance of the SWAT model. Three quantitative statistics, namely Nash-Sutcliffe efficiency (NSE), percent bias (PBIAS), and ratio of the mean square error to the standard deviation of measured data (RSR), in addition to the graphical techniques, were identified to be used in model evaluation. Results of calibration and validation of the model at a monthly time step gave NSE of 0.65, Pbias of 15 and RSR of 0.4, while NSE of 0.5, Pbias of 31 and RSR of 0.5 were recorded for validation. According to monthly model performance ratings, the model performed well during calibration and performed satisfactory during the validation stage.

Thesis (M. Tech.) -- Central University of Technology, Free State, 2008 / The aim of the study was to determine radiation dose levels around the theatre table, on either side of the C-Arm, in order to establish if the radiation dose received by staff during back pain procedures fell within the limits set by the International Commission of Radiological Protection (ICRP). The question that arose from this goal was whether the stance of staff, in relation to the x-ray tube side of the C-Arm, influenced radiation dose levels. In order to apply the ALARA principle, the possibility of lowering the radiation dose in the neurological theatre was explored. The measurement methodology of the study was twofold: measurements were executed by means of TLD meters, as well as with an ionisation chamber. TLD meters were placed on the patient, the neurosurgeon and the radiographer during back pain procedures, and, more specifically, during fluoroscopy, to record the doses with the Image Intensifier (II) above the table as well as with the x-ray tube above the table, at the pelvis and the chest height of the staff. Ionisation chamber measurements were recorded in 25cm intervals around the theatre table with a phantom and the C-Arm positioned in the PA, oblique and lateral positions at 110cm and 133cm heights from the floor. The TLD results indicated that, when compared to the Image Intensifier side, the radiation dose was higher on the x-ray tube side of the C-Arm. The radiation dose was higher at the height closest to the x-ray source. The radiation dose received by the patient was higher with the x-ray tube positioned above the table (PA). The radiation dose to the surgeon’s hand and body was higher with the x-ray tube positioned above the table (PA). Radiation dose levels with the x-ray tube above the table during back pain procedures in the current theatre exceeded the occupational annual recommendation of 500mSv to the neurosurgeons hands, as recommended by the ICRP. The opposite is true with the II positioned above the table. The research question was answered positively in that the x-ray tube under couch orientation has the potential to limit dose levels during back pain procedures. The measurement values resulted in a proposed protocol in terms of positioning of staff and orientation of the C-Arm in order to apply the ALARA principle during back pain procedures. Constant revision of protocols is the responsibility of the radiographer in order to guarantee that the ALARA principle is implemented in every unique situation.

Thesis (D. Tech.) -- Central University of Technology, Free State, 2010 / Branded dairy products have lately become a global trend. As a result of this, the origin of the milk used in the manufacturing of branded cheeses must be declared by the producer, since it is known that these products are highly adulterated with foreign milk. In South Africa, branded Ayrshire Cheddar cheese has become highly popular due to its unique organoleptic properties and in light of claims that it ripens much faster than cheese made from other milk (not including Ayrshire). This study was therefore directed to investigate the unique properties of branded Ayrshire Cheddar cheese versus Cheddar cheese manufactured from a mixture of other breeds’ milk (not including Ayrshire milk) and to establish a catabolite profile for each cheese type. The outlay of the thesis was constructed into six chapters each with its own outcomes. The first chapter focused on the variations between the two Cheddar cheese batches (produced from Ayrshire and other breeds’ milk) with regards to organic acid, selected chemical parameters and starter microbiotia. In the following three chapters mathematical models were developed that would predict organic-; fatty and amino acid fluxtuations respectively in the cheese made from Ayrshire and other milk. In the last chapter two artificial neural networks were designed with the two starter organisms, Lactococcus lactis and Streptococcus thermophilus as variable indicator respectively. Thirty-two cheese samples of each batch (pure Ayrshire (4) / mix breed with no Ayrshire (4)) were ripened and samples were analysed under the same conditions on the following days after production: 2, 10, 22, 36, 50, 64, 78, and 92. In the subsequent chapters, the following analysis were done on each day of analysis: organic acid by means of high performance liquid chromatography (HPLC); fatty acids by means of Gas Chromatography Mass Spectometry (GCMS); amino acids by means of GC-MS; microbial analysis by means of traditional methods, total DNA extraction and polymerase chain reaction (PCR); and standard chemical analysis for moisture, NaCl and pH. In the first research chapter, the minimum and maximum (min/max) values, standard deviations and proposed rel X values of organic acids were evaluated in Ayrshire and the mixed-breed Cheddar cheese, and showed that isovaleric acid is the organic acid with the least variation relative to concentration in both cheeses and it was assumed that this organic acid is the most effective indicator of cheese uniformity. Clear differences in organic acids, chemical variables and starter micro-organisms were also evident in the two cheese batches. Results obtained from the regression models which was defined for each organic -; amino - and fatty acid by means of mathematical equations can be used by the manufacturer to achieve i.e. the selection of cheese for specialist lines, the early exclusion of defective cheeses, and the establishment of brand origin (Ayrshire vs. mixed-breed Cheddar cheeses). The regression graphs also illustrate unique flux patterns in Ayrshire and the mixed-breed in terms of organic -, fatty -, and amino acid content. In the last chapter, the discrimination between the two batches was respectively done via artificial neural network (ANN) modelling of Lactococcus lactis and Streptococcus thermophilus as indicator organisms. The ANN consisted of a multilayered network with supervised training arranged into an ordered hierarchy of layers, in which connections were allowed only between nodes in immediately adjacent layers. The construction thereof allowed for two output nodes, connected to an input layer consisting of two nodes to which the inputs were connected. In both cheeses the results from the ANN showed acceptable classification of the cheeses based on the counts of L. lactis and S. thermophilus.

Thesis (D. Tech. (Clinical Technology)) -- Central University of technology, Free State, 2013 / Objectives: Survival with end stage kidney disease (ESKD) is made possible by dialysis but is in turn associated with increased morbidity, mortality, and decreased quality of life (QOL). Quality of life is a frequently overlooked, yet a critical consideration in evaluating the overall medical care of ESKD patients. This study aimed to evaluate the QOL of chronic haemodialysis (HD) and peritoneal dialysis (PD) patients in multiple dialysis units in South Africa. Methods: A comparative descriptive study carried out on 100 haemodialysis (HD) (n=100) and 100 peritoneal dialysis patients (PD) (n=100) patients, evaluating factors such as demographics, duration on dialysis, medical history, clinical indicators and the patient’s understanding thereof, was performed. Quality of life was measured using the medical outcomes study 36 (SF-36). These factors, clinical scores and QOL measures were compared amongst HD and PD patients and thereafter correlated to nephrology professionals’ perspective on QOL. Results: A total of 200 (n=200) patients from 11 dialysis units were evaluated. Mean age for the HD group was 49±15 years compared to 53±14 years for the PD group (p=0.043). The HD patient group had an improved physical composite (PCS) score adjusted for age, urea, creatinine and albumin (p<0.001). The mental composite score (MCS) was improved in the PD group although not significant (p>0.05). A positive correlation was found, as PD patients had an improved symptom control score, adjusted for age (p=0.04), an improved effect of kidney disease score adjusted for albumin (p=0.000), and an improved burden QOL score adjusted for urea, creatinine and albumin (p=0.019). Age was shown to be associated to the physical functioning (p=0.01) and PCS (p=0.040), and diabetes to the emotional role (p=0.04), in QOL. An increase in the years on dialysis showed a reduced emotional well-being (p=0.028) and being on the transplant list an improved MCS (p=0.003). Participation in a pre-end stage kidney disease (PESKD) management programme showed improvement in the general health component (p=0.032), the effect (p=0.01), and the burden of kidney disease (p=0.02). Assessing patients’ knowledge on ESKD revealed the relationship of the PCS to the understanding of managing the complications associated with CKD (p=0.01) and access management (p=0.01). The understanding of diet was found to be significant to the burden of CKD (p=0.01) and the complications associated with CKD was found to be further significant to the effect and symptom QOL (p=0.01). Nephrology professionals rated the difficulty of living with kidney disease a 7.49 out of 10 score and 71% felt QOL is taken into consideration with managing ESKD patients. Conclusion: The study demonstrated differences in the adjusted QOL scores amongst HD and PD dialysis patients in the dialysis units studied. The importance of PESKD was emphasized in relation to improved QOL. Quality of life is a valid marker and important for the ongoing audit of renal services.

Thesis (M. Ed. ) - Central University of Technology, Free State, 2013 / The drafting and promulgation of education policies bring hope and an expectation to those whose interests, concerns and problems, are addressed by them. On the other hand, such policies bring confusion, uncertainty and stress to teachers who are expected to implement and put into practice prescripts of those policies. Response to the Education White Paper 6: Special Needs Education – Building an Inclusive Education and Training System (2001) and subsequent policies on inclusive education which followed, brought uncertainty to teachers and also led to some developing a negative attitude towards inclusive education. This study focused on the implementation of inclusive education in primary schools in the Lejweleputswa District of the Free State province. A literature review provided insight into the concept of inclusive education and moreover shed light on policy developments regarding learner diversity through the curriculum. An empirical investigation using a qualitative approach was conducted and data was gathered by means of focus group interviews with school-based support teams as well as a questionnaire completed by principals. Furthermore, the findings of the empirical investigation concurred, to a large degree, with the findings of the literature study. In general, it was brought to light that inclusive education is not implemented correctly in primary schools in the Lejweleputswa District. Based on certain findings, recommendations are made regarding the successful implementation of inclusive education in primary schools.

Thesis (M. Tech.(Biomedical Technology)) - Central University of Technology, Free State, 2010 / Introduction: Geophagia, generally referred to as earth-eating, occurs in many countries of the world, including African countries such as South Africa. A need was identified to characterize human geophagic habits and the microbiological content of geophagic clayey soil, including the presence of potentially pathogenic nematodes (geohelminths), in South Africa. Materials and methods: Questionnaires were developed to generate data on human geophagia and included demography, socio-economics, indigenous knowledge, business aspects, mining and hygiene practices of vendors/geophagists. A total of 52 soil samples (n = 52) were collected from the district of Thabo Mofutsanyane (Free State, South Africa), which comprised of vendor, topsoil, excavated and control soil sample groups. Nematode content were isolated using the Ammonium bicarbonate protocol, thereafter the nematodes were classified and population sizes determined for each sample. Soil colour classification was completed using the Munsell Soil Color Charts. Results and discussion: The questionnaire revealed that geophagia in this region was practised mainly by women of child-bearing age because of the taste of the soil. Vendors sell geophagic clayey soil (known as mobu) collected from the mountain- and riversides for subsistence, generally costing one to two rand per bag. Hygiene and environmental conditions are considered when mining geophagic clayey soils. Whitish-perceived clayey soils are preferred by most of the geophagists. According to the Munsell Soil Color classification, Thabo Mofutsanyane geophagic soils ranged from brownish, to greyish, to yellowish in colour. Vendor soils were mostly greyish, while topsoils, excavated soils and control soils were mostly brownish. No human pathogenic nematode ova or larvae were isolated from any of the samples, however 34 nonpathogenic nematode taxa representing five trophic levels were identified. These included mainly herbivores, but also fungivores, bacteriovores, omnivores and predators. Taxon richness (number of taxa) greatly varied in the soil sample groups with vendor soil n = 9, topsoil n = 24, excavated soil n = 16 and control soil n = 14. Tylenchus sp., Criconemoides sphaerocephalus and Ditylenchus sp. were the only nematode taxa identified in all the different sample groups, with Tylenchus sp. notably more abundant overall. When the median nematode population sizes were compared between the geophagic soil samples, no significant difference (p ≥ 0.05) could be identified. In contrast, the median nematode population sizes for all samples differed significantly (p < 0.05) from the control soil sample group. Conclusion: This study revealed that geophagia is probably not a vector for geohelminth infection in the district of Thabo Mofutsanyane, South Africa. However, the rich presence of non-pathogenic soil nematode communities in these brownish, greyish and yellowish geophagic soils may be useful as biological indicators of general soil health.