1,721,005 research outputs found
Thermo-mechanical analysis of energy piles through numerical and centrifuge tests
No full textFor over thirty years, finite element analyses and centrifuge tests have been successfully applied to investigate the response of a large series of geotechnical engineering problems. However, although the capability of finite element analysis to capture the thermal-induced mechanical behaviour of real-scale energy piles has been assessed, the suitability of centrifuge tests for the same purpose has not yet been validated despite their increasing application. This paper investigates the capability and suitability of centrifuge tests for describing the thermal-induced mechanical behaviour of energy piles based on a comparison between a series of results obtained through numerical and centrifuge analyses. In particular, it analyses the response of energy piles in dry sand subjected to mechanical and thermal loads. The study outlines the appropriateness of centrifuge tests for the considered purpose and remarks crucial points that have to be considered when modelling energy pile-related-problem
A non-linear constitutive model for describing the mechanical behaviour of frozen ground and Permafrost
No full textThe mechanical behaviour of frozen ground and permafrost is changing under the increasing variation of
environmental and anthropogenic boundary conditions. This phenomenon affects many civil structures and
infrastructures built in Polar and Alpine areas. Mathematical formulations able to capture the mechanical
behaviour of frozen ground and permafrost with adherence to reality and a limited employment of
technical resources and time appear crucial for the engineering design and retrofit of these structures. To
address this challenge, this study presents a relatively simple elasto-plastic constitutive model for capturing
the non-linear mechanical behaviour of frozen silt. The model is based on associated flow rules.
It employs an elliptical yield surface and a parabolic yield surface for describing the volumetric mechanisms
that characterise the modelled material, together with a parabolic yield surface for describing the
deviatoric mechanism. Comparisons with experimental triaxial test results available in the literature highlight
the suitability of the model to capture the non-linear mechanical response of frozen silt subjected to
both low and high confining pressures. This result, together with the doable implicit consideration in the
model of the effects induced by environmental boundary conditions such as temperature on the mechanical
behaviour of the material, makes this tool attractive for simplified yet thorough analyses of frozen ground
and permafrost-related problems
Numerical study of the response of a group of energy piles under different combinations of thermo-mechanical loads
No full textEnergy piles are rapidly gaining acceptance around the world because they represent a renewable and clean source of energy that can be used for the heating and cooling of buildings, and the de-icing of infrastructures. This technology couples the structural role of pile foundations with an energy supply using the principle of shallow geothermal energy. The exploitation of geothermal energy represents an additional thermal load that is imposed to the foundation and the surrounding soil. Because the primary role of energy piles is the stability of the overlying structure, this aspect must be ensured even in the presence of the additional thermal load. This study summarises the results of 3-D thermo-hydro-mechanical finite element analyses that investigated the behaviour of a group of energy piles for which field data were available. This allowed the nearly unique validation of the numerical approach with experimental data and a confirmation of the reliability of the results. The work provides a summary of the foundation behaviour under both conventional and extreme thermal loading conditions with reference to a geothermal operation of the piles for cooling and/or thermal energy storage applications within one season. The interaction between the piles is studied and the thermally induced group effects analysed. Attention is dedicated to the vertical stress and displacement developments in the piles. The results presented in this study outline crucial aspects that may be considered by engineers for the geotechnical and structural designs of such geostructure
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
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