879 research outputs found

    Modeling the effects of seasonal weather and site conditions on wind turbine failure modes

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    It is important that the impact of the offshore environment on wind turbine reliability is reduced significantly due to the importance of offshore wind deployment to global energy targets. Future development may otherwise be compromised by unsustainable operation and maintenance (O&M) costs. This paper aims to improve the accuracy of offshore O&M models by accounting for any relationship between certain weather characteristics and wind turbine failure modes. This is done using maintenance data from a UK onshore wind farm and weather data from a weather station located nearby. Non-parametric Mixture Models are estimated from the data and they are used to calculate a more accurate, weather dependent, failure rate which will be used in future research for Markov Chain Monte Carlo Simulation. This research will be of particular interest to wind turbine operators and manufacturer

    Modelling the impact of the environment on offshore wind turbine failure rates

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    For offshore wind turbines to become an economical energy generation option it is vital that the impact of the offshore environment on reliability is understood. This paper aims to model the impact of the wind speed and the external humidity and temperature. This is achieved using reliability data comprising of two modern, large scale wind farm sites consisting of approximately 380 wind turbine years of data. Weather data comes from a nearby weather station and an onsite met mast. A model is developed, using the reliability data, which calculates weather dependant failure rates and downtimes which are used to populate a Markov Chain. Monte Carlo simulation is then exercised to simulate the lifetime of a large scale wind farm which is subjected to controlled weather conditions. The model then calculates wind farm availability and component seasonal failure rates. Results show that offshore, the wind speed will have the biggest impact on component reliability, increasing the wind turbine failure rate by approximately 61%. The components affected most by this are the control system and the drive train. The higher offshore wind speeds appear to cause a higher proportion of major failures than experienced onshore. Research from this paper will be of interest to operators and wind turbine manufacturers who are interested in maintenance costs and logistics

    Five Sijo

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    Translations from the Japanese of Hagiwara Sakutaro

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    Four Translations from the Japanese

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    Visiting the Shwe Dagon

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    Fathers as co-parents: how non-resident fathers construe family situations after divorce or separation

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    A model of the co-parental role based on personal construct theory is described, with inter-parental conflict explained in terms of the constructivist concept of hostility. Four unstructured group interviews, on the theme of the experience of separated parenthood, were conducted with separated fathers (n=14) from throughout Strathclyde. Thematic analysis of the results suggests that while participants recognised the importance of maintaining relations with the other parent, that relationship was seen as adversarial, and fathers frequently feel controlled or powerless; different strategies for coping with this control emerged. From common post-separation parenting experiences recounted by the participants, situational elements were developed for a series of repertory grid interviews, intended to identify and examine the co-parental role construct system. Grids were administered, at three points over a year, to a cohort of separated, non-resident fathers from Strathclyde (n=17) still in contact with their children. The results were analysed using construct content categories developed for this research, inter-element distance measures, and asymmetric coefficients to assess ordinal relationships between constructs. Support was found for the model of a co-parental role covering interactions with children and their mothers. Perceptions of parity in parents' flexibility regarding contact arrangements were associated with recent experience, particularly ongoing disputes over contact allocation, and reflect strategies for dealing with being controlled. Conflict emerges as having distinct and multiple implications for separated non-resident fathers, whose responses to change were also consistent with the constructivist conception of hostility. One strategy for dealing with this may be a gradual distancing from the role of co-parent, in line with recent theories of core construing. These findings are discussed along with strengths and limitations of this research; implications for policy, practice and future research are outlined

    A work-integrated learning mentorship model for nature conservation at an open distance learning university in South Africa

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    In this dissertation of limited scope, the phenomenon of providing effective workintegrated learning mentorship to nature conservation undergraduate students is explored, specifically to determine if mobile technology can be offered as an alternative or supplementary mentoring strategy for an Open Distance Learning university. Mentoring of work-integrated learning undergraduate students is an integral component of the Nature Conservation Diploma offered by the University of South Africa. The prerequisite mentoring of students is not consistent across all required sector-based placements and this could be construed as being unjust and discriminatory. This possible negative perception has motivated this investigation into work-integrated learning mentorship approaches within the Nature Conservation Diploma. This exploratory case study provides insights into and lays a foundation for the development of a supplementary mentorship provision strategy, for students who find it difficult to secure mentorship opportunities. Applying a social learning and integration perspective, three cohorts of undergraduate nature conservation work-integrated learning students participated in this study. This qualitative exploratory case study focused on the interaction and subsequent results achieved by students, through engaging with one of three different mentorship methods available to students at the University of South Africa. The three methods were: face-to-face mentoring by an academic, digital mentoring provided by means of a mobile phone application and sector-based mentoring. The latter method represents the current mentorship provision status quo for all nature conservation work-integrated learning diploma students. The findings reveal that the three mentoring methods are effective in supporting workintegrated learning students. The students indicated their preference for mentorship provided by the University of South Africa, over that of the sector-based mentors. No significant difference between the two university-provided methods of mentorship was found. This study recommends that the University continue with its development of the digital mentor option, to function as a fully functioning supplementary mentor.Curriculum and Instructional StudiesM. Ed. (Open and Distance Learning

    An investigation into the online customer experience

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    This paper explores the online customer experience in relation to Government provision of business support services. The aim of this research is to understand the variables that can influence customers searching for business support services online and to explore the potential role of social interaction during a customer’s online experience. This study provides a theoretical framework outlining the variables that have the potential to influence the online customer experience within the business support environment. The initial methodology is outlined along with an explanation of the current phase of the research
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