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Thermo-hygro-chemo-mechanical modeling of the behavior of a massive beam with restrained shrinkage
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A multiphase concrete model with application to high temperature, structural repair, leaching and Alkali-Silica reaction
No full textPoro-mechanical model of strain hysteresis due to cyclic water freezing in partially saturated porous media
No full textThe paper presents a novel mathematical model of coupled hygro-thermo-mechanical processes in a porous material, partially saturated with liquid water and exposed to temperatures below the freezing point of pore water. Water – ice phase change is modelled by means of a non-equilibrium approach considering both water supercooling and a hysteresis of ice content during freezing and thawing of moist porous materials. The hysteresis results in different crystallization pressure and material strains during freezing and thawing processes at a given temperature. The latter effect is modelled by means of the effective stress principle, considering crystallization pressure of ice in the material pores. Methods used for discretization of the model equations and their numerical solution are described. The model is applied for solving the numerical example dealing with laboratory Dynamic Mechanical Analysis test of two different cement mortars saturated with water and exposed to temperatures below the freezing point of water (down to −15 °C) where hysteresis of strains was observed. The results are used for experimental validation of the proposed model. Then, for a 1-D case concerning water freezing-thawing of a wall, the effects on the simulation results of the phase-change model parameters, of the material hygro-thermal state, of the supercooling phenomenon and finally of the rate of temperature variation, are analyzed and discussed
Non-equilibrium modeling hysteresis of water freezing: Ice thawing in partially saturated porous building materials
No full textThis article presents a novel mathematical model of hygro-thermal processes in a porous material, partially saturated with liquid water, exposed to temperatures below the freezing point of pore water. Water–ice phase transition is modeled by means of a kinetic approach considering water supercooling and thermodynamic non-equilibrium of the phases, what allows taking into account a hysteresis of ice content during freezing–thawing of moist porous materials. The model equations are solved for two numerical examples. The first one deals with laboratory differential scanning calorimetry test of a cement mortar saturated with water and exposed to temperatures below the freezing point of water (down to −40°C). The results are used for experimental validation of the proposed model, confirming its accuracy and practical usefulness. In the second example, the mesh refinement test is performed and the influence of the solid–liquid water phase change model parameters on the simulation results for a 1D model problem concerning water freezing–thawing are analyzed and discussed
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
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