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Optimization of condition-based maintenance strategy prediction for aging automotive industrial equipment using FMEA
Get PDFAbstract: Maintenance plays a highly important role in achieving production targets and system performance. Electromechanical equipment and facility infrastructure within motor manufacturing industries are expected to perform at optimal efficiency during the operational phase of production. A major problem in the automotive production plan from motor industry statistics is associated with unexpected downtime, which is largely linked to aging equipment. During production downtime, much time is lost to fault finding, repairs, and replacement of faulty components within production lines. This transforms into low throughput in production, and performance gradually declines during the operational life cycle of the equipment. This paper presents an approach taken to prevent such instances in the automotive manufacturing industry, which considers an optimized condition-based maintenance approach to predict the condition of each component and assembly line using Failure-Mode-and-Effect-Analysis (FMEA). The condition-based performance level prediction is designed to help in formulating maintenance schedules and strategies that eliminate unplanned downtimes
The ethnobotany of marula (Sclerocarya birrea, Anacardiaceae) in South Africa
Get PDFAbstract: Please refer to full text to view abstract.M.Sc. (Botany
The effects of fluid thinning in gear tribology
Get PDFAbstract: ”To mechanical progress there is apparently no end: for as in the past so in the future, each step in any direction will remove limits and bring in past barriers which have till then blocked the way in other directions; and so what for the time may appear to be a visible or practical limit will turn out to be but a bend in the road. (Opening address to the Mechanical Science Section, Meeting of the British Association, Manchester.)” Osborne Reynolds. Lubricants are divided into two types, liquid lubricants, and gaseous lubricants. They are used to minimize frictional wear in mechanical systems and improve the efficiency and life span of mechanical systems. There is a little over 10,000 different types of lubricants throughout the world, with liquid lubrication being the most dominant and most studied type of lubricant, liquid lubricants include but are not limited to synthetic oils and petroleum oils.M.Sc. (Pure and Applied Mathematics
Effects of alloying on aluminium-silicon alloys – a review
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Jumpstart programme impact on mathematics learning outcomes : a cross-sectional quasi experiment using the early grade mathematics assessment
No full textAbstract: This paper contributes to the research agenda on intervention studies and their impact on learning outcomes. It focuses on early grade mathematics in South Africa by drawing on four years of cross-sectional data (n = 5,724) from treatment and control primary schools in the same district in Gauteng. Early Grade Mathematics Assessments (EGMA) were administered to a random selection of learners in both school groups over a period of 4 years. Findings show a statistically significant difference in mean attainment on the EGMA assessment in the JumpStart schools (effect size of 0.52) and with further improvements evident after 3 years (effect size of 0.94). These effect sizes are compared to existing South African studies as well as meta-analysis of studies from low- and middle-income countries. Benchmarks for EGMA raw score attainment at Grade level in the Ekurhuleni South district of Gauteng (n = 2,625) are provided
Changes in the neuroanatomy and neurogenic activity in the hippocampus of the Zucker Diabetic Sprague Dawley (ZDSD) rat
Get PDFAbstract: Diabetes mellitus is a growing health concern both abroad and within South Africa, as 8.3% of the entire South African population was estimated to be afflicted with this condition in 2013 and is projected to increase to 9.9% by 2035. Most T2DM animal models have defective leptin signalling, which does not mirror the human condition. The aim of the study was to investigate the type 2 diabetes related changes in the neuroanatomy and neurogenic activity of the Zucker Diabetic Sprague Dawley (ZDSD) rat, a rodent model with an intact leptin signalling pathway. The ZDSD rats were monitored for the development of T2DM, by measuring changes in body mass, fasting blood glucose, insulin resistance and lipid profiles. The anatomical structure (volume and cell counts) of the ZDSD rat hippocampus was assessed with Cresyl violet staining. The neurogenic activity within the model was assessed with Ki-67 and DCX immunohistochemistry. Changes in the concentration of serum analytes (MDA and BDNF) were also measured in the ZDSD rats...M.Tech. (Biomedical Technology
Convergence or divergence patterns in global defence spending : further evidence from a nonlinear single factor model
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The identification of factors contributing to negative handover experiences of pre-hospital emergency care personnel in Johannesburg, South Africa
Get PDFAbstract: Introduction The handover of a patient in the pre-hospital setting is different to other handover settings and therefore requires a different definition and description to that of other patient handover environments. Identifying those factors that affect the efficacy of handover could provide useful for formulating improvement strategies. Aim This research set out to describe the negative experiences of pre-hospital emergency care personnel handing over in the emergency centre in Johannesburg, South Africa, with a view to identifying potential areas for improvement. This paper reports on responses to an open-ended question that formed part of a purpose-designed, paper-based questionnaire that formed part of a mixed-methods study. Methods Data were collected from pre-hospital emergency care personnel within Johannesburg, South Africa. Responses from 140 participants were captured verbatim into Atlas.ti® for coding, analysis and interpretation using a qualitative descriptive methodology. Two themes were generated from a qualitative descriptive analysis of the data: communication barriers, and process barriers to emergency centre handover. These were confirmed by the categories and codes that made up these themes. Conclusion This study identifies some of the factors perceived by pre-hospital emergency care personnel to negatively affect emergency centre handover. It provides insights into how communication and process within the emergency centre have the potential to negatively impact emergency centre handover efficacy
Validating indigenous versions of the South African personality inventory
Get PDFAbstract: Personality assessments are frequently used to make decisions and predictions, creating a demand for assessments that are non-discriminatory. South African legislation requires psychological tests to be scientifically proven to be valid, reliable, fair and nonbiased. In response to the necessity for a measure sensitive to indigenous differences, South African and Dutch researchers developed the South African Personality Inventory (SAPI). The SAPI represents a theoretical model of personality that uses an indigenous (emic) and universal (etic) approach to capture South Africa’s rich multicultural and multilingual view of personhood. The development of SAPI items and its simultaneous translation from English into all official languages necessitated the investigation of all the translated language versions’ psychometric properties. This study used Exploratory Structural Equation Modelling to examine the factor structure and model fit of two indigenous language versions of the SAPI, targeting the Tshivenda and the Southern Sotho languages. To accomplish this objective, Study 1 (N = 290) was done in South Africa among the Tshivenda ethnic group, while Study 2 (N = 293) was conducted in South Africa among the Sesotho ethnic group. An acquiescence response pattern was noticed in both studies, possibly to adhere to group consensus and emphasizing harmony within relationships. The ESEM solutions generated an excellent fit for both language versions, and most facets loaded acceptably on their expected factors. The Neuroticism factor proved to be problematic in both language versions. Within the Tshivenda version, the Emotional Stability facet did not generate adequate loadings on any SAPI factors. In contrast, neither Emotional Stability nor Negative Emotionality loaded sufficiently on the Neuroticism factor for the Southern Sotho version. While the overall fit of the six-factor model was excellent, the language in which a person completes a personality questionnaire seems to influence such an assessment’s factor structure. The Tshivenda and Sesotho versions of the SAPI cannot yet be positioned as equitable alternatives when using an indigenous version of the SAPI is needed. The implications of the results and proposals for future studies are discussed
Blood lead levels associated with childhood exposure to lead in Ekurhuleni District day-care centres
Get PDFAbstract:M.Tech. (Environmental Health
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