Thesis (M. Tech.) -- Central University of Technology, Free State, 2009 / Automated Guided Vehicles (AGVs) have many different design specifications, although they all have certain design features in common, for instance they are designed to follow predetermined paths, and they need to be aware of their surroundings and changes to their surroundings. They are designed to house sensors for navigation and obstacle avoidance. In this study an AGV platform was developed by modifying an electric wheelchair. A serial port interface was developed between a computer and the control unit of the electric wheelchair, which enables the computer to control the movements of the platform. Different sensors were investigated to determine which would be best suited and most effective to avoid collisions. The sensors chosen were mounted on the AGV and a programme was developed to enable the sensors to assist in avoiding obstacles. An imaging device as an additional sensor system for the AGV was investigated. The image produced by a camera and dome mirror was processed into a panoramic image representing an entire 360o view of the AGV‟s surroundings. The reason for this part of the research was to enable the user to make corrections to the AGV‟s path if it became stuck along the track it was following. The entire system was also made completely wireless to improve the flexibility of the AGV‟s applications.

Thesis (M. Tech.) -- Central University of Technology, Free State, 2008 / As the tendency to use sol id freeform fabrication (SFF) technology for the manufacture of end use parts grew, so too did the need for a set of general guidelines that would aid designers with designs aimed specifically for rapid manufacture. Unfortunately, the revolutionary additive nature of SFF technology left certain fundamental principles of conventional design for manufacture and assembly outdated. This implied that whole chapters of theoretical work that had previously been done in this field had to be revised before it could be applied to rapid manufacturing. Furthermore, this additive nature of SFF technology seeded a series of new possibilities and new advantages that could be exploited in the manufacturing domain, and as a result drove design for rapid manufacturing principles even further apart from conventional design for manufacture and assembly philosophy. In this study the impact that rapid manufacture had on the conventional product development process and conventional design for manufacture and assembly guidelines were investigated. This investigation brought to light the inherent strengths and weaknesses of SFF, as well as the design for manufacture and assembly guidelines that became invalid, and consequently lead directly to the characterization of a set of design for rapid manufacture guidelines.

Thesis (B. Tech.) - Central University of Technology, Free State, 2007

Thesis (M. Tech.) - Central University of Technology, Free State, 2009

Thesis (D. Tech.) -- Central University of Technology, Free State, 2007 / Success in today’s competitive business environment demands innovative approaches. Organisations must be able to react effectively and make informed decisions in order to be in the best position to take advantage of collaborated business opportunities in the organisation’s external network. The results of strategic decisions are affected by the strategic choices that are made and how successfully those objectives are implemented. In many cases the strategies have mediocre success or fail to achieve what they set out to do due to the failure to formulate and implement strategies that enhance the development of a sustainable competitive advantage in the long term. The case study organisation, MultiChoice Africa (Pty) Limited, serves as an example in understanding the knowledge base imperative in utilising strategic management instruments such as Kaplan and Norton’s (1996a: 8-18, 224-292) Balanced Scorecard to guide leadership in creating real-time value, thereby creating a sustainable competitive advantage. Balanced Scorecards have largely been developed and applied to internal managerial purposes, though they are seldom used for external marketing. The purpose of this research was to evaluate the strategic value of the Balanced Scorecard in the networked economy, utilising a case study design by following a phenomenological paradigm approach. The outcome was based on a pre- and postanalysis of the implementation of the Balanced Scorecard within the case study organisation, focusing on the perceived value towards overcoming the barriers to strategy implementation, developing a competitive advantage and sustaining this advantage. Sustainability was specifically defined and tested against the environment and ethical behaviour as the results indicated that a link exists between sustainable competitive advantage and the appropriate utilisation of the Balanced Scorecard. Research results suggest that respondents appear to be enthusiastic and have started the process of transforming the organisation into a ‘Balanced Scorecard organisation’. The main advantages included an increased awareness of vision, linking operational tasks to strategic employees’ participation and flexibility. Shortcomings, on the other hand, included the perceived lack of contribution of the Balanced Scorecard to the final outcome as well as to the transformation process. A number of limitations were evident in the design, deployment and utilisation of the Balanced Scorecard in overcoming the barriers to strategy implementation and how to gain a sustainable competitive advantage in the networked economy. Important aspects surrounding employees and stakeholders were also highlighted as the design of the case study organisation’s original Balanced Scorecard is based on its value chain. However, due to the networked economy and its implications for the organisation, the Balanced Scorecard architecture should be modified to make provision for a networked design. These modifications should incorporate additional constructs that need to be taken into consideration when creating larger networks and establishing collaborative communities of practice. Key to the organisation’s future strategic value and intent is the successful implementation of change management (transformation) as a driver into the application of the Balanced Scorecard in the networked economy. Insight gained was used to propose a theoretical model based on global business landscape demands, utilising new and innovative strategies and business model architectures that require the convergence of aggregated metrics of all role players in the borderless network, as outlined in the ‘Networked Balanced Scorecard’ theoretical model. The theoretical model outlines how organisations can reform and integrate their Balanced Scorecards to support strategy formulation, implementation and control. It therefore supports sustainable competitive advantage and is based on embracing components of competitive intelligence and collaboration in the networked economy. It is thus suggested that organisations can no longer implement sustainable competitive advantage strategies in isolation, but need to focus on organisational development strategies that encapsulate the network concomitance structure and architecture, thereby attaining the new value proposition for strategic intent.

Thesis (M.Tech.) - Central University of Technology, Free State, 2006

Thesis (D. Tech. (Biomed. Tech.)) -- Central University of Technology free State, 2010 / Consumer demands for fresh, microbiologically safe foods with high organoleptical and nutritional quality has led to the development of novel food preservation technologies as alternatives or enhancements to traditional preservation techniques. An example of these novel preservation technologies is high hydrostatic pressure (HHP) processing. It involves the applications of static pressure of 50 to 1 000 mega Pascals (MPa) to solid or packaged liquid foods, with varying holding times. The combination of factors to enhance preservation is increasingly being used in industry, e.g. the use of different temperatures and additives (hurdles) can enhance the preservative effect of HHP. In this study the influence of HHP on organism viability and growth response was assessed. The organisms evaluated included Escherichia coli O111, Listeria monocytogenes (UAFSBCC) and Staphylococcus aureus (ATCC 25923), in peptone water, which was subjected to HHP of 200 MPa for 15 minutes at 8 and 50 ºC respectively. Subsequent to the mentioned pressurisation, sub-culturing was performed and growth responses were evaluated at 0, 6, 18, 24, 30, 42 and 48 hours. Bacterial survival and growth response was measured by means of intact cell count, colony forming units and optical density. From the results it was eminent that bacterial cells were only sublethally injured and were able to repair within 48 hours of enriched sub-culturing. E. coli O111 proved to be most sensitive to HHP with Staphylococcus aureus (ATCC 25923) most resistant. This study also proved that bacterial concentration and inactivation rate are inversely proportionate to each other. Subsequent to growth and cell repair assessments, E. coli O111 was selected as a model to evaluate the effect of sublethal HHP on the liberation and toxicity of bacterial endotoxins (free and cell wall bound). It is also known that different extraction procedures extract different lipopolysaccharides (LPS) fractions and therefore LPS was extracted from the test broth by a combination method of Folch, Lees & Sloane-Stanley, and Venter and Ivanov. The extraction yielded a biphasic system, LPS with reduced lipid content in the upper phase (aqueous) and LPS with increased lipid content in the lower phase (organic). Following extraction the Limulus amebocyte lysate (LAL) test was performed to quantify the concentration (assumed) of LPS in the aqueous and organic phases. Free LPS was detected within six hours in the supernatant in the high and low bacterial loads, moreover the toxicity response of post HHP cell damage was more pronounced at 50 ºC (hurdle) than that observed for the treatments at 8 ºC (hurdle) and more so in the organic phases. The latter implied that HHP not only resulted in quantity LPS variation but also in structural change. However membrane repair was apparently complete after 48 hours, as differences in toxicity were no longer evident. Furthermore, the use of a porcine IL-6 ELISA assay was evaluated as an alternative for the customary LAL as a biomarker for pyrogenic substances in matrixes. Porcine whole blood was challenged for IL-6 production by LPS in the samples from the organic and aqueous systems. A porcine IL-6 enzyme-linked immunosorbent assay was used to assess IL-6 expression in whole blood after being challenged with LPS. From the results it emanated that HHP caused in a change in LPS structure which resulted in a decreased IL-6 expression in whole blood, indicating that structural adaptation of the cell membrane in response to HHP influenced the ability of LPS to stimulate macrophages and monocytes. Therefore, further research and development would be required to evaluate the influence of post HHP LPS on human IL-6 expression. When comparing the porcine IL-6 with the LAL no correlation in toxicity could be established in any of the treatment parameters. Finally it can be concluded that HHP had an influence in the structural morphology of LPS. These structural changes could result in LPS being more toxic, it could also have an effect on the accuracy of immunological assessments, the ability to form biofilm, and susceptibility to phages.

Thesis (M. Tech. (Biomed. Tech.)) -- Central University of Technology, Free State, 2010 / The World Health Organization (WHO) has warned in 2005 that: “Coronary heart disease is now one of the leading causes of death worldwide. It is on the rise and has become a true pandemic that respects no borders” (WHO, 2005). The Heart and Stroke Foundation of South Africa more specifically estimates that approximately 33 (thirty‐three) people per day will die of a heart attack in South Africa. Despite the already high death toll resulting from AIDS in South Africa, death from a chronic disease, also including heart disease, will increase from 565 deaths per day in the year 2000, to 666 deaths per day by 2010 (Steyn, 2007). Acute coronary syndrome (ACS) is an ‘umbrella term’ describing a heterogeneous spectrum of clinical symptoms compatible with acute myocardial ischaemia (Monaco, Mathur, Martin, 2005; ACC/AHA, 2007) and an ongoing inflammatory process resulting from atherosclerosis. ACS can either be treated medically (pharmacological treatment), by percutaneous coronary intervention (PCI), or by performing coronary artery bypass graft (CABG) surgery either through on‐pump or offpump CABG surgery. By treating the ACS patient by means of CABG surgery, an inflammatory response is further triggered on top of the already existing inflammation resulting from atherosclerosis. This leads to a systemic inflammatory response (SIR), which may eventually lead to systemic inflammatory response syndrome (SIRS). This study focuses on the inflammatory response initiated by the CABG technique applied during the revascularisation of the ACS patient. Many past studies compared on‐pump and off‐pump CABG surgery, arguing not only the advantages and disadvantages of these surgeries, but also the outcomes regarding SIRS. Both types of surgery are associated with an inflammatory response resulting from tissue trauma and the use of the extracorporeal circulation (EC) in CABG surgery (Quaniers, Leruth, Albert, Limet, Defraigne, 2006). This non‐randomised, observational study primarily aimed to assess and compare the pre‐ and the post‐operative inflammatory markers between (n=60) patients with ACS undergoing either on‐pump CABG (n=30) or off‐pump CABG surgery (n=30). A secondary objective was to ascertain whether a correlation exists between the pre‐operative risk factors, the surgical procedure and the pre‐ and post‐operative inflammatory markers. Three inflammatory markers ‐ full blood count (FBC), procalcitonin (PCT) and C‐reactive protein (CRP) ‐ were analysed employing normal routine laboratory analysis. Interleukin‐6 (IL‐6) and tumour necrosis factor alpha (TNF‐α) were analysed using an enzyme amplified sensitivity immunoassay (EASI) method. The inflammatory markers were analysed pre‐operatively (baseline) and post‐operatively and at different time intervals (24, 48, 72, 96 and 120 hours post‐operatively). Pre‐operatively, all the leucocytes were already elevated in both CABG groups, as could be expected in patients with ACS resulting from the already existing atherosclerotic process and the consequent pre‐operative existing inflammatory response. A significant pre‐operative difference was moreover detected in respect of the lymphocytes between the two CABG groups (p=0.03024). A significant post‐operative difference was also detected between the two CABG groups. The following significantly elevated levels were detected in the on‐pump CABG surgical group: for WCC at 24 hours (p=0.00761), 48 hours (p=0.01520) and 72 hours (p=0.00004); for neutrophils at 24 hours (p=0.17422), 96 hours (p=0.18611) and 120 hours (p=0.12872); for lymphocytes at 48 hours (p=0.04829) and at 96 hours (p=0.01982); and, for PCT at 24 hours (p=0.00811), 48 hours (p=0.00966) and 72 hours (p=0.01823) . However, measurable values of IL‐6 levels were found to be higher in the off‐pump CABG surgical group, with significant differences manifesting between the two CABG groups at 96 hours (p=0.05352) and 120 hours (p=0.09729). No differences between the two groups could be demonstrated for eosinophils, basophils, monocytes, CRP and TNF‐α. In conclusion: despite the demonstrable inflammatory responses in both CABG groups, no difference in clinical outcomes was observed. The inflammatory responses evoked by on‐pump and off‐pump CABG procedures will, for some time to come, remain an area of interest for future research, but they are certainly not the only factors to have a bearing on surgical outcomes. The impact of intraoperative events needs to be elucidated further ‐ and in more detail ‐ in order to attempt to determine the relationship of these events on the extent of inflammatory responses and clinical outcomes, irrespective of whether the procedure is performed with or without cardiopulmonary bypass.

Thesis (M. Tech.) -- Central University of Technology, Free State, 2010 / This main aim of this study was to assess patients in a general cardiology practice in order to determine the systolic and diastolic profiles of these patients. The aim was also to determine what effect life style and risk factors may have on the echocardiographic variables measured during such an examination. The specific aim of this study was the importance of not only examining the systolic function but the necessity to also examine the diastolic profile of patients. Life-style plays an important role, with the main culprit being obesity. Obesity was the single most important factor that affected the diastolic profile of patients seen in this study. With obesity a combination of other risk factors related to obesity was observed. Most abnormalities found due to these risk factors were associated with diastolic changes in the left ventricle. Echocardiography is routinely used in daily practice, but the diagnostic value of this tool can be enhanced if proper analyses of the systolic as well as the diastolic profiles are determined. Many cardiologists only measure the systolic function of the heart as an indication of the well- being of the left ventricle, although in this study it was proven that systolic function did not alter with ageing or with changes in the risk profile. Hundred-and-twelve patients, divided into three age groups, were evaluated in this study. Both systolic and diastolic variables were measured and analysed for abnormalities. None of these patients had systolic function abnormalities, although they had detectable anatomic changes due to ageing, obesity and hypertension. Several abnormalities were found on the diastolic profile of these patients. Muscle thickness increased due to obesity and hypertension and even with ageing, but with no significant abnormalities in the systolic function of the heart. There was a slight increase in the circumferential shortening of the left ventricle and that both the septal and longitudinal functions decreased with ageing. It is noteworthy that even where the systolic function remained normal in ageing subjects, their diastolic profiles changed significantly. Assessment of left ventricular function required a meticulous and systematic approach. In this study forty- one percent of patients visiting this general practice had abnormalities of their diastolic function although their systolic function was normal. It was found that with ageing, especially in the older age group, important abnormalities occur in their diastolic profile. The most common changes were that the E- peak velocity decreased and that the Apeak velocity of the trans-mitral flow increased. It seemed that passive filling decreased with ageing but that active filling increased simultaneously, causing the cardiac output to remain constant in older subjects. This is important to know because diseases affecting the atrium may have a profound effect on the cardiac output of older patients, even if they have normal systolic function, (due to the decreased passive filling they need their active filling or atrial contraction to support a normal cardiac output). An important marker will be to look at the ratio of the E/A- velocities in older patients to determine the ratio of active against passive filling. Other than that, a relatively new tool in echocardiography called tissue Doppler was used to determine what happened to the muscle with ageing. Here it was demonstrated that the different layers of the left ventricle acted differently with ageing. Results showed that the longitudinal fibres weakened with ageing although the circumferential fibres remained unchanged or even strengthened with ageing. It was apparent in this study that the traditional use of only systolic function may not be adequate when evaluating relative asymptomatic patients presenting at a general cardiology practice. It is important to also evaluate the diastolic profiles of these patients in order to scientifically quantify their heart health, even in asymptomatic patients. It is important to routinely evaluate the diastolic profile of patients so that early detection of these diastolic variables can be detected and timely consideration for its treatment can be given by their cardiologist. It is also important to take note of the significance of the obesity problem and the effect it has on the heart’s health. In conclusion, this study emphasizes the importance of the echocardiographic evaluation of diastolic cardiac function in addition to routine systolic evaluation in asymptomatic patients. This will enable the clinician to detect abnormalities early and tailor therapy accordingly. Lifestyle related risk factors, especially obesity, also have significant effects on diastolic cardiac function.

Thesis (M. Tech.) - Central University of Technology, Free State, 2010 / Early detection of mother-to-child transfer of Human Immunodeficiency Virus (HIV-1) is of the utmost importance for monitoring the success of intervention strategies, as well as for optimal treatment of HIV-positive children. Serology can only be used confidently after 18 months, as remaining antibodies from the mother may give false positive results. This leaves only molecular methods for early detection of the virus; unfortunately, the technology is still too expensive for general use. The aim of this project was to develop and validate a cost-effective, fast, early detection method for HIV infection in infants. PCR was chosen as the developmental method, a technique that amplifies proviral sequences of HIV DNA, detecting HIV infection in peripheral blood mononuclear cells (PBMC) from infants of seropositive women during neonatal (age less than 28 days) and post-neonatal periods. A method based on the commercial Roche HIV-1 DNA assay was chosen for implementation on the Roche LightCycler instrument. The published primer set was used to detect both HIV-1 DNA and an internal control. The target DNA for use as internal control was constructed from the plasmid pBR322 so that an AT-rich part of the plasmid was flanked by the HIV-1 primer-binding sites. The resulting amplicon was cloned into a vector and multiplied in E. coli. Amplification of the plasmid by PCR in the Roche LightCycler in the presence of SYBR Green created an amplicon having a Tm different (81 ± 1°C ) from that of the HIV-1 amplicon (84 ± 1°C) so that post-amplification melting can be used to differentiate between HIV-1 and internal control. After construction of the internal control, the reaction conditions were optimised so that the internal control would amplify strongly only in the absence of HIV-1 target DNA. Then 50 previously tested patient samples were analysed using the assay developed here. Only half of the known positive samples came up positive in the assay, indicating that it is not sensitive enough for diagnostic use in its current form. Various ways of improving the sensitivity are suggested for further development of the assay as described here.