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Numerical modelling of an experimental energy pile
No full textGeothermal energy is a way of reducing the cost of energy. Deep geothermal energy systems extract heat from very deep soil layers where the temperatures are very high. Shallow geothermal energy systems are about 150 metres deep and they are used to store heat in the soil, to extract it later and use it for space heating. These shallow geothermal systems are generally embedded in a borehole, but they can also be cast into structures, which are called thermo-active foundations. An example of such a foundation is the energy pile, a foundation pile with a heat exchanger embedded in it, connected to a heat pump. There is no need to drill an extra hole in the ground, but the downside is that it is not well known how the bearing capacity of the pile is affected by the heating/cooling cycles. An energy pile experiment is planned to investigate the thermo-mechanical behaviours of the pile and the goal of this thesis is a numerical investigation of the pile. It serves as an estimate of the pile and soil behaviour prior to installation and the results will be used to confidently design the experiment. The model was built with DIANA FEA software, that is capable of coupling thermo-mechanical behaviour. Firstly an experiment in London clay was recreated in order to verify and validate the model and modelling approach. The experiment in Delft was modelled using site investigation that was done at the location where it will be built. Along with old Cone Penetration Test (CPT) data the subsurface was mapped and soil parameters used in the material model were chosen. The thermal cycle that was imposed on the pile was chosen on the basis of preliminary modelling done at different temperature increments. The temperatures were chosen such that the pile was affected to a significant degree of its capacity. It was cooled for three weeks to 0 °C and then heated to 24 °C for three weeks, this was repeated for 6 years. The research focussed on finding which thermo-mechanical effects can be expected and what the scale of those effects could be. The effect directly linked to an increase in temperature is thermal strain. Materials tend to expand and contract with the temperature at different rates and so do the pile and the soil. The gradient of the heat flow is also an important factor as the pile is subjected to the temperature before the soil is. The pile will expand first and this will be resisted by the soil, the strain that is resisted by the soil is called the restrained strain and that is responsible for the change in stress in the pile. A pile that is heated will have more stress than with just a mechanical load and a pile that is cooled will see a reduction in stress. The pile will expand vertically around a null-point somewhere along the pile, this is the point that does not move. In principle, an unrestrained pile will have a null-point in the centre of the pile, but because some soil layers resist the pile movement more than others the null-point is closer to the stronger layers. In the Delft experiment model the null-point was halfway down the pile at first, but as the amount of cycles progressed it moved down. This is due to a decrease in resistance from the weaker layers and an increase in resistance in the strong sand layer on which the pile is based. The amount of stress that is generated is also less in these later cycles as the resistance of the soil became less. With that reduced resistance an increase in settlement is also seen. This can lead to differential settlements of structures that are built on such a pile, possibly damaging them. The results of the modelling are used to give an advice on the experiment details, such as geometry, thermal cycle and pile layout. An advice to the layout of the sensors is included as well as a prediction of the results
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
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
Regulating privatized infrastructures and airport services
Get PDFFor a World Bank Institute course on transport privatization, the authors cover basic issues associated with the regulation of privatized airport infrastructure and services: 1) Economic characteristics of airport. Three types of activities are carried out in airports: essential operational services (aeronautical and non-aeronautical), handling services (aeronautical and non-aeronautical), and commercial activities. Demand for basic airport services is directly influenced by trip purpose. The two types of airline customers (business and leisure travelers) need different levels of flexibility and tend to travel at different times. Analyzing airport capacity (practical and saturation) under peak demand is essential to airport success. Among other important issues: runway cost, level and volume of service, pollution, congestion, and air traffic control. 2) Recent trends in the airport industry. The movement toward privatization may involve public ownership and private operation, including joint ventures; partial or majority divestiture; management contracts; and BOT (build-operate-transfer) schemes and variants, including BOOT (build-own-operate-transfer) schemes and LDO (lease-develop-operate) schemes. Or it may involve private ownership and operation. 3) Price regulation. Topics covered include traditional pricing policies'price regulation through an RPI-X formula; charges for congestion, noise, and other externalities; investment plans; and design of the regulatory system. 4) Regulation of quality in the industry. Topics covered: regulation of services to passengers (as measured by targets for check-in queues, immigration queues, baggage reclaim queues, concourse crowding, shopping, parking, and so on); fault repair times; average levels of passenger boarding and disembarkation and baggage delivery; safety; and investment obligation. 5) Performance indicators in the industry. Topics covered: strategic indicators and other financial indicators (including revenues), as well as indicators of cost, productivity, and quality of service.Transport and Trade Logistics,Public Sector Economics&Finance,Banks&Banking Reform,Environmental Economics&Policies,Decentralization,Roads&Highways,Airports and Air Services,Public Sector Economics&Finance,Banks&Banking Reform,Transport and Trade Logistics
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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