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Wind energy is one of the most promising sources of renewable energy. Unfortunately, therapid growth in wind turbine technology is not equally at par with the improvement in itsreliability. Wind turbine systems tend to fail before their design life and hence result in asizeable amount of failure cost. A lack of reliable data has plagued the reliability and risk assessment of wind turbines in the scientific community. Many efforts have been made to estimate the failure probability of these systems and highlight the critical failure modes. However, there is a knowledge gap in quantifying the effect of the root cause of failure. This thesis work bridges this gap by developing a reliability analysis tool that quantifes the impact of a root failure cause, based on the resultant cost of failure. Furthermore, an attempt to quantify the importance of tribology in wind turbines is made. The model uses two independent reliability estimation methods - Fault Tree Analysis and Failure Mode and Effect Analysis. The two resulting approaches are used to prove the model's versatility and ease of adaptation of the model in the industry. Furthermore, with the inclusion of 'Reliability Influencing Factors', this model can calculate the overall potential economic gain from improving one or multiple properties of a component. The report then illustrates one of the industrial use cases of the model. With wind turbine gearbox as a representative assembly, tribology's quantitative importance is depicted against the Levelised Cost of Energy. It is concluded that a 2.5% decrease in energy cost can be achieved with just a 5% improvement in wind turbine gearbox tribology. / Vindenergi är en av de mest lovande källorna för förnybar energi. Tyvärr matchas inte den hastiga utvecklingen i vindturbinteknologi med en likvärding utveckling i dess pålitlighet. Vindturbinsystem tenderar att fallera tidigare än designats för, vilket resulterar i en betydande falleringskostnad. En avsaknad av tillförlitlig data har hindrat utvärderingen av påalitlighet och risk för vindturbiner. Många ansträngningar har gjorts för att estimera sannolikheten att dessa system ska fallera och att lyfta fram de kritiska fellägena. Däremot finns det en kunskapsbrist när det kommer till att kvantifiera effekten av den grundläggandeorsaken till fallering. Denna avhandling minskar denna brist genom att utveckla ett verktyg för pålitlighetsanalys som kvantifierar effekten av en falleringsorsak baserat på den resulterande kostnaden för fallering. Vidare görs ett försök att kvantifiera vikten av tribologi i vindturbiner. Modellen använde två oberoende metoder för estimering av pålitlighet - Fault Tree Analysis and Failure ode and Effect Analysis. De två resulterande angreppssätten används för att påvisa hur anpassbar modellen är och hur lätt modellen kan användas i industrin. Vidare, med inklusionen av 'Reliability Influencing Factors' kan modellen beräkna den övergripande potentiella ekonomiska vinningen från att förbättra en eller flera delar av en komponent. Rapporten illustrerar sedan en av de industriella användningsområdena av modellen. Med en vindturbins växellåda som representativt exempel påvisas den kvantitativa vikten av tribologi mot 'the Levelised Cost of Energy'. Slutsatsen dras sedan att en 2.5% minskning i energiförbrukning för konsumenten kan nås med endast en 5% förbättring av tribologin i en vindurbins växellåda.

Call number: LD2668 .T4 1978 C56 / Master of Science

Call number: LD2668 .T4 1978 K87 / Master of Science

Call number: LD2668 .T4 1978 L445 / Master of Science

Call number: LD2668 .T4 1979 K37 / Master of Science

Call number: LD2668 .T4 1984 L58 / Master of Science

Nurses experience stress, fear and anger while they are trying to reconcile their ideals/ goals about health care with its inadequacies and abuses (Jameton, 1984:5), while at the same time trying to stay true to their convictions (Lindh et al., 2010:552). Moral distress is experienced when nurses cannot adhere to these goals (Corley, 2002:637). Conflicting moral principles, stress-provoking and contradicting demands weaken the nurse’s sense of control, power and autonomy (Lützen et al., 2010:213). The current descriptions of moral distress inadequately define the concept, and this might lead to the inconsistent use of the term moral distress. Therefore, conceptual clarity is needed. Current available instruments measure antecedents and situations causing moral distress. Therefore, an instrument measuring the attributes of moral distress is urgently needed. Such an instrument might be used in a variety of clinical departments because it is not based on department-specific situations but on the attributes of moral distress. Moral distress has a great impact on the nurse, patient care and the organization. This research used Benson and Clark’s (1982) method of instrument development as a theoretical framework. It is the aim of this study to develop and validate an instrument to measure moral distress in the clinical health care context of the professional nurse. In order to attain this aim the following objectives were set: To conduct an integrative literature review to identify antecedents, consequences, attributes and empirical indicators of moral distress; to conduct interviews to explore professional nurses’ experience of moral distress; to develop an instrument to measure moral distress in professional nurses; to validate the instrument. A qualitative and quantitative research design with explorative, descriptive and contextual strategies was used. The research process was divided into phases. During Phase One, an integrative literature review was conducted and the population included all available national and international data on moral distress in nurses/ nursing and sampling included all-inclusive sampling. Data analysis was performed through descriptive synthesis.Phase Onealso included semi-structured interviews and the population included professional nurses working in hospitals and clinics in the North-West Province. The sampling method applied was purposive sampling. Tesch’s method was used as data analysis method. During Phase Two, a content validation was conducted and the population included experts in the field of moral distress and instrument validation, and purposive sampling was applied. Data collection was done through the instrument that was developedand data analysis was the content validity index. Phase Twoalso included a qualitative evaluation which was conducted and the population consisted of professional nurses working in hospitals and clinics in the North-West Province and purposive sampling was applied. Data was collected through the developed instrument and a focus group session. Data analysis was conducted through aconsensus discussion. During Phase Three, a pilot study was conducted and the population was professional nurses working ina hospital with different departments and clinics in the Free State Province. All-inclusive sampling was applied and the instrument that was developed was used as data collection. Data analysis included: Descriptive statistics, factor analysis (exploratory, confirmatory and Bartlett’s test of spherity), Cronbach’s alpha coefficient, correlations and ANOVA. According to the results from the face-, content-, exploratory and confirmatory, discriminant- as well as divergent validity, the instrument has been shown to be valid. The Cronbach’s alpha for the Moral Distress Instrument was deemed reliable. Finally, the research was evaluated and limitations were identified. Recommendations for nursing education, -practice, research and policy were formulated. / PhD (Nursing), North-West University, Potchefstroom Campus, 2014

Cellular networks in Africa have grown exponentially over the past 10 years and their data centres (DCs) on average consume 3 MW of electrical power. They require a reliable electrical power supply and can have a downtime loss of over a million dollars per hour. Power quality, reliability and availability have emerged as key issues for the successful operation of a data centre. Investigations are carried out into emerging technologies and their application in data centre power distribution systems for cellular networks in Africa. Best practices are applied to develop a power distribution system (PDS) with the objective of achieving optimal reliability and availability. Analytical techniques are applied to determine and compare the reliability and availability of various power systems. Minimal cut set simulations identify system weak points and confirm component selection. Components’ inherent characteristics (CIC) and system connectivity topology (SCT) are key factors in the improvement of data centre availability. The analysis practices can be used by engineers and managers as a basis for informed decision making in determining power system reliability and the availability of an existing or a new data centre design. Weak points in the PDS of a data centre causing downtime are identified through analysis, and accurate solutions can be determined to prevent or minimise downtime. System connectivity topology (SCT) techniques were identified that could increase the reliability and availability of data centres for cellular networks in Africa. These techniques include multiple incomers from the utility company, redundancy levels of critical equipment and parallel distribution paths. Two case studies were carried out on data centres for a cellular network, one in Nigeria and one in Cameroon. The reliability and availability of both data centres was improved, with substantial reduction in downtime per year. The outcome of the case studies shows the importance of designing and implementing the power distribution system with sufficient levels of redundancy for critical equipment, and parallel distribution paths. / MSc (Engineering Sciences in Nuclear Engineering), North-West University, Potchefstroom Campus, 2014

Nurses experience stress, fear and anger while they are trying to reconcile their ideals/ goals about health care with its inadequacies and abuses (Jameton, 1984:5), while at the same time trying to stay true to their convictions (Lindh et al., 2010:552). Moral distress is experienced when nurses cannot adhere to these goals (Corley, 2002:637). Conflicting moral principles, stress-provoking and contradicting demands weaken the nurse’s sense of control, power and autonomy (Lützen et al., 2010:213). The current descriptions of moral distress inadequately define the concept, and this might lead to the inconsistent use of the term moral distress. Therefore, conceptual clarity is needed. Current available instruments measure antecedents and situations causing moral distress. Therefore, an instrument measuring the attributes of moral distress is urgently needed. Such an instrument might be used in a variety of clinical departments because it is not based on department-specific situations but on the attributes of moral distress. Moral distress has a great impact on the nurse, patient care and the organization. This research used Benson and Clark’s (1982) method of instrument development as a theoretical framework. It is the aim of this study to develop and validate an instrument to measure moral distress in the clinical health care context of the professional nurse. In order to attain this aim the following objectives were set: To conduct an integrative literature review to identify antecedents, consequences, attributes and empirical indicators of moral distress; to conduct interviews to explore professional nurses’ experience of moral distress; to develop an instrument to measure moral distress in professional nurses; to validate the instrument. A qualitative and quantitative research design with explorative, descriptive and contextual strategies was used. The research process was divided into phases. During Phase One, an integrative literature review was conducted and the population included all available national and international data on moral distress in nurses/ nursing and sampling included all-inclusive sampling. Data analysis was performed through descriptive synthesis.Phase Onealso included semi-structured interviews and the population included professional nurses working in hospitals and clinics in the North-West Province. The sampling method applied was purposive sampling. Tesch’s method was used as data analysis method. During Phase Two, a content validation was conducted and the population included experts in the field of moral distress and instrument validation, and purposive sampling was applied. Data collection was done through the instrument that was developedand data analysis was the content validity index. Phase Twoalso included a qualitative evaluation which was conducted and the population consisted of professional nurses working in hospitals and clinics in the North-West Province and purposive sampling was applied. Data was collected through the developed instrument and a focus group session. Data analysis was conducted through aconsensus discussion. During Phase Three, a pilot study was conducted and the population was professional nurses working ina hospital with different departments and clinics in the Free State Province. All-inclusive sampling was applied and the instrument that was developed was used as data collection. Data analysis included: Descriptive statistics, factor analysis (exploratory, confirmatory and Bartlett’s test of spherity), Cronbach’s alpha coefficient, correlations and ANOVA. According to the results from the face-, content-, exploratory and confirmatory, discriminant- as well as divergent validity, the instrument has been shown to be valid. The Cronbach’s alpha for the Moral Distress Instrument was deemed reliable. Finally, the research was evaluated and limitations were identified. Recommendations for nursing education, -practice, research and policy were formulated. / PhD (Nursing), North-West University, Potchefstroom Campus, 2014