1,720,971 research outputs found
Numerical study on the effects of scour on monopile foundations for Offshore Wind Turbines: The case of Robin Rigg wind farm
Full text linkScour around monopiles supporting Offshore Wind Turbines (OWT) may cause a significant reduction in the foundation capacity and the natural frequencies of the soil–structure system. The decommission of two monopiles at the Robin Rigg wind farm after only six years of operation due to massive unexpected scour demonstrates the hazard that an active marine environment poses to OWT. Assessing and predicting the quantitative impact of scour on monopile foundations from a point of view of the utilisation of the foundation capacity is hence crucial to its long-term structural and operational safety. Using finite element analysis, the present study quantifies the influence of scour through moment
and lateral load
(
) interaction curves and Load Utilisation (LU) ratios. It analyses the first and second natural frequencies of OWT exposed to different scour morphologies. This methodology is applied to a large-diameter monopile embedded in sand and to the scour-induced failed foundation of the Robin Rigg wind farm. The results indicate that, with increasing scour depth, the
capacity and the natural frequencies are reduced due to the loss of lateral confinement. The response of the system is found to depend on the rigidity of the pile governed by the slenderness ratio, the capacity of the soil to redistribute loads with increasing scour, and the effects of overburden pressure on deeper unscoured soil layers. The LU methodology has proven to be an appropriate and efficient approach to predict the long-term performance of scoured monopiles
Independence and the market for electricity in Scotland
No full textIn liberalised electricity markets the impact of further constitutional change depends on the reaction of all the relevant transactors involved in the supply and demand for electricity. This includes the manner in which supplies and demands are balanced and the way in which the market is structured and regulated. A comprehensive analysis would thus require a detailed study of the impact on the “supply side” of the market (generation, transmission, distribution and supply), as well as on the “demand side” (households, firms, government). Furthermore, the fact that electricity cannot easily be stored raises balancing issues, and the Government, both directly and indirectly (through its influence on the market structure and the regulatory framework), influences behaviour at all levels. In this paper we do not aspire to a comprehensive analysis, given the difficulties of delivering that at this stage. A full analysis, for example, would require further information concerning electricity market reform and greater evidence of the impact of constitutional change in these circumstances. Rather, we seek to focus on a number of key areas that we believe will govern the eventual impact of independence. Under the status quo, many of the elements of the electricity market are outwith the control of the Scottish Government and are reserved to Westminster. The promotion of renewables, the resistance to new nuclear and the adoption of legally binding climate change targets are examples where successive Scottish administrations have used devolved powers to, in essence, pursue a distinctive Scottish energy policy (Allan et al, 2008). However, many of the key aspects of electricity market policy (including market regulation, taxation, etc.) are, under current constitutional arrangements, beyond the control (though not necessarily the influence) of the Scottish Government. Significant constitutional change may alter some aspects of market structure and transactor behaviour (for better or worse). But change under independence may not be dramatic if, for example, a unified GB electricity market is maintained and there is little substantive difference in regulation in practice, despite the establishment of a separate Scottish regulator, as the current Government again intends (e.g. Ewing, 2013; Scottish Government, 2013). We organise our discussion around the likely impact of further constitutional change on the ability of the Scottish Government to achieve its energy policy goals, though we focus primarily on effects that are linked to possible developments in the electricity market.1 In liberalised markets, energy policy involves the use of policy instruments to induce private transactors to behave in a way that achieves targets as well as the ultimate policy objectives, subject to constraints. In the Scottish and UK context the major policy objectives include: security of supply; environment protection (limiting carbon emissions to inhibit climate change); economic development (in a sustainable manner) and energy affordability. Additionally economic development potential has received rather greater emphasis in Scotland (where energy is one of the Government’s key growth sectors) than in the UK as a whol
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Responses of two marine top predators to an offshore wind farm
Full text linkQuantifying the likely effects of offshore wind farms on wildlife is fundamental before permission for development can be granted by any Determining Authority. The effects on marine top predators from displacement from important habitat are key concerns during offshore wind farm construction and operation. In this respect, we present evidence for no significant displacement from a UK offshore wind farm for two broadly distributed species of conservation concern: common guillemot (Uria aalge) and harbor porpoise (Phocoena phocoena). Data were collected during boat-based line transect surveys across a 360 km2 study area that included the Robin Rigg offshore wind farm. Surveys were conducted over 10 years across the preconstruction, construction, and operational phases of the development. Changes in guillemot and harbor porpoise abundance and distribution in response to offshore wind farm construction and operation were estimated using generalized mixed models to test for evidence of displacement. Both common guillemot and harbor porpoise were present across the Robin Rigg study area throughout all three development phases. There was a significant reduction in relative harbor porpoise abundance both within and surrounding the Robin Rigg offshore wind farm during construction, but no significant difference was detected between the preconstruction and operational phases. Relative common guillemot abundance remained similar within the Robin Rigg offshore wind farm across all development phases. Offshore wind farms have the potential to negatively affect wildlife, but further evidence regarding the magnitude of effect is needed. The empirical data presented here for two marine top predators provide a valuable addition to the evidence base, allowing future decision making to be improved by reducing the uncertainty of displacement effects and increasing the accuracy of impact assessments
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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