1,720,956 research outputs found
Modelli variazionali per la progettazione e la diagnosi dell’evoluzione e dello stato di ammaloramento di dighe in calcestruzzo.
No full textThis research investigates the complex interplay between structural mechanics and material degradation in civil engineering and soil. The focus is on two primary areas: the long-term behaviour of concrete dams subjected to aging and the limitations of linear models in capturing seismic response.
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Aging-induced deterioration in concrete dams is primarily attributed to the diffusion of deleterious substances, which subsequently trigger internal chemical reactions. This study proposes a unified hemivariational framework for investigating damage and deformation in concrete dams subjected to aging-related processes. The model incorporates both one-dimensional (Timoshenko beam) and two-dimensional representations of the dam structure.
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A novel aspect of the proposed approach is the introduction of an "external distributed aging fluid influx pressure" as a dual of the concentration of the aging fluid. This pressure drives the inward diffusion of the aging agent, which is coupled with the evolution of damage. Parametric analyses are conducted to evaluate the influence of diffusivity and damage-concentration coupling term on the damage progression and service life prediction.
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The results indicate that the dam's shape significantly impacts stress distribution and, consequently, damage initiation and propagation. For the bi-dimensional case a more refined damage threshold is introduced to account for the distinct compressive and tensile behaviours of concrete. The proposed modelling approach provides a robust framework for assessing the long-term performance and safety of aging concrete dams, with potential applications in structural health monitoring and life cycle management.
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The same theory is also used to investigate a particular phenomenon we called \textit{apparent} creep because the underlying mechanism is analogous to the processes occurring subsequent to classical creep deformations. This phenomenon, observed in a two-dimensional polymeric beam, exhibits characteristics akin to creep, as evidenced by numerical simulations demonstrating increased displacements under constant external loading conditions due to fluid ingress into the domain.
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The presence in soils of deteriorating fluids induce modifications of its mechanical characteristics. However, it is important to preliminary investigate.
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Additionally, one more research investigates the limitations of linear models in capturing the complex behaviour of geomaterials subjected to extreme loading conditions, such as those induced by seismic events. The research challenges the conventional linear paradigm in geophysics and civil engineering, particularly in the context of seismic events. %
This research investigates the influence of non-linear material behaviour on seismic response. A non-linear viscoelastic model is developed to capture large deformations near geological discontinuities, commonly observed in complex geological settings (such as those observed in the Aterno River Valley). Numerical simulations demonstrate the critical role of non-linearity in accurately predicting ground motion characteristics, including frequency content and amplitude. By combining these factors, the research provides a comprehensive framework for enhancing the reliability and accuracy of seismic hazard assessment and structural analysis. The findings contribute to the development of advanced computational tools for mitigating seismic risk and ensuring the safety of critical infrastructure
Fluid diffusion related aging effect in a concrete dam modeled as a Timoshenko beam
No full textAging related damage within a concrete dam is often associated with the diffusion of certain particles which then activate internal chemical action. In this paper, a hemivariational method for a nonhomogeneous and damaged Timoshenko beam model is proposed in order to describe damage and deformation in a dam caused by the diffusion of an aging fluid. The proposed model is used to perform a suite of parametric studies. In these studies, the dam is subjected not only to the concentrated and distributed external forces and couples (dual of displacement and rotation of the section, respectively) but also to the dual of the concentration of the aging fluid, called external distributed aging fluid influx pressure, that drives the incoming flow of the aging fluid which is, for this purpose, coupled with the damage evolution. The results are utilized to predict the life time of the dam. The life of big structures is a crucial point in civil engineering because it is linked with the safeguarding of human life
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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