1,720,969 research outputs found
Nonlinear rocking dynamics of pre-tensioned single rigid blocks under harmonic base excitation
No full textThe rocking mechanism has been widely recognized as a beneficial technique to reduce structural damage arising from lateral excitations particularly earthquake loading, and hence, segmental pre-tensioned bridge piers have been recently emerged due to their self-centring property accompanied by accelerated construction of such structures. Hence, this study formulates the rocking dynamics of tied pre-tensioned single rigid blocks as an initial study for better understanding of dynamics of segmental pre-tensioned bridge piers. The nonlinear equation of rocking motion is then numerically solved under different range of base harmonic excitations. To achieve this, the rocking initiation condition is considered to determine initial conditions of rocking motion, an implicit solution is adopted to solve the equation of rocking motion and determine rocking response. Finally, a study is performed on a specific composite tied block to investigate effects of geometry and initial pre-tensioning force of the cable on the dynamic behaviour of the block. This study can find use in better understanding of segmental pre-tensioned columns.</p
On the use of entangled wire materials in pre-tensioned rocking columns
No full textThis research explores potential application of entangled wire materials as intermediate layers between segments of pre-tensioned segmental bridge columns. An ensemble of free-decay vibration tests was conducted on small-scale columns with various configurations of intermediate layers. Wooden blocks were used for segments and the entire system was tightened together using a pre-tensioned steel tendon. Damping and frequency of the columns were determined and compared. It is demonstrated that entangled wire materials substantially increase total damping of the entire system in rocking. This result is very encouraging for future application of entangled wire materials in testing large-scale pre-tensioned segmental bridge columns. However, shear and axial stiffness of the layers require further improvement to reduce their large shear and axial deformations.</p
Influence of advanced structural modeling and subduction mainshock-aftershock sequences on seismic fragility of RC structures
No full textCurrent seismic codes and standards in practice aim at preventing collapse of structures but do not address serviceability and performance of the buildings after a major earthquake adequately. For instance, following a mainshock, ground motion activities, known as aftershocks, occur as a cluster, potentially causing incremental damage to structures whose seismic capacities may be reduced by the mainshock. This paper proposes an advanced structural modeling technique, which can simulate various features of cyclic deterioration and degradation in material and structural components using nonlinear fiber beam-column elements. The proposed model accounts for inelastic buckling and low-cycle fatigue degradation of longitudinal reinforcement, and can simulate the multiple failure modes of reinforced concrete structures under dynamic loading. Furthermore, a comprehensive ground motion selection accounting for subduction earthquakes, is implemented. Finally, a new set of fragility curves has been developed, which accounts for the structural modeling and aftershock effects. The proposed methodology significantly improves the accuracy of seismic risk and vulnerability assessment by reducing the uncertainties associated with structural modeling and variability of earthquake ground motions.</p
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
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