1,720,962 research outputs found
Coupled hydro-mechanical modelling of the seismic response of a zoned earth dam
Full text linkGlobal climate change is leading to prolonged periods of low rainfall followed by intense thunderstorms, causing
severe droughts in vital water resources like rivers and reservoirs. Additionally, heavy rainfall events are causing
landslides and significant damage in many countries. Dams and artificial water reservoirs are crucial in mitigating
these risks. Given the limited availability of suitable sites for constructing new reservoirs, existing dams must be
safeguarded, although they also pose seismic vulnerability risks due to the uncontrolled release of water. Therefore, it
is crucial to assess the seismic performance of earth dams and plan rehabilitation works accordingly. This paper focuses
on the coupled hydro-mechanical modelling of the seismic response of a zoned earth dam. The model was calibrated
using results from a geotechnical centrifuge test, simulating the impoundment phase and applying increasing levels of
seismic input. The comparison between the predicted and observed behaviour demonstrated the efficacy of the finite
element (F.E.) model in accurately capturing the key characteristics of the response exhibited by this complex
geotechnical system when subjected to dynamic loads
Seismic response analysis of a zoned earth dam including vertical input motion
No full textMany existing earth dams were designed before the establishment of a seismic code or in a period when the seismicity of the dam sites was approximately assessed. Accordingly, the evaluation of their seismic performance is a crucial issue and, for both new and existing dams, the design or retrofitting procedures should aim to the improvement of their seismic resilience. In this framework the dynamic analyses devoted to the prediction of the dam seismic performance are usually carried out accounting only for the horizontal component of the expected ground motion. However, the vertical seismic motion can play an important role since it could affect the earthquake induced plastic mechanisms and the magnitude and distribution of the corresponding permanent strains. In this vein, the paper presents the results of a large set of 2D finite-elements dynamic analysis carried out with reference to a zoned earth dam located in a high seismic area of Southern Italy, using an isotropic hardening elasto-plastic hysteretic model. The analyses point out the influence of the amplitude and energy content of the vertical component of the input motion on the dam performance. Specifically, the numerical results are presented and discussed focusing on the on the magnitude of the crest settlements, considered a good proxy of the seismic-induced level of damage, and on their relationship with the seismic parameters describing the energy and frequency content of the vertical component of the input motion
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
The Static and Seismic Bearing Capacity Factor Nγ for Footings Adjacent to Slopes
No full textAbstractFoundations resting adjacent to the crest of a slope exhibit a smaller bearing capacity respect to the case of horizontal ground. In this paper the static and seismic values of the bearing capacity factor Nγg for shallow strip foundations adjacent to slopes were evaluated using the method of characteristics, extended to the seismic case by means of the pseudo-static approach. Nγg was evaluated for different values of the slope angle and, under seismic conditions, accounting only for the effect of horizontal and vertical inertia forces arising in the foundation soil. The results, for both smooth and rough foundations, are presented and checked against those obtained through finite element analyses
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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