1,720,955 research outputs found
Parametric study and prediction models of the seismic response of single-degree-of-freedom structural systems equipped with Maxwell material fluid viscous dampers
No full textThe addition of supplemental damping through fluid viscous dampers has been widely implemented as a seismic protection system for diverse typologies of structures. Typically, fluid viscous dampers are modelled using a Maxwell material model, which accounts for the stiffness of the damper device and its support assembly. However, the influence of the different parameters involved in the design of Maxwell fluid viscous dampers on the dynamic response of damped systems subjected to transient loads has not been studied thoroughly, especially regarding the acceleration response of dynamic systems. This paper discusses the results of a parametric study of the influence of several damper's design parameters, such as the velocity exponent, the supplemental damping level, the seismic intensity, and the Maxwell material stiffness, and the interaction among them, on the seismic response of viscously damped single-degree-of-freedom structural systems. Non-linear time history analyses were carried out using the FEMA P-695 far-field ground motion set scaled to four increasing intensities. The seismic response was measured in terms of peak relative displacements, peak relative velocities, peak damper forces, peak floor absolute accelerations, and peak floor absolute acceleration response spectra. Based on the obtained seismic responses, several prediction models were proposed using Gaussian Process Regression to provide an insight into the influence of the different design parameters of fluid viscous dampers on the seismic response of viscously damped single-degree-of-freedom structural systems. The results show that the different parameters involved in the design of Maxwell fluid viscous dampers significantly influence the efficiency of damper devices and the seismic response of the single-degree-of-freedom structural systems, especially in terms of acceleration response. For particular combinations of the damper's design parameters, significantly higher floor spectral accelerations can be observed in some period ranges compared to those of control systems without dampers. Additionally, the floor absolute acceleration response spectra exhibit a stiffening effect caused by the implementation of fluid viscous dampers, shifting peak floor spectral accelerations to shorter periods. The magnitude of the stiffening effect is proved to be correlated to the Maxwell material stiffness value
Seismic Demand on Acceleration-Sensitive Nonstructural Components in Viscously Damped Braced Frames
No full textThis paper investigates the seismic demand on acceleration-sensitive nonstructural components in buildings equipped with fluid viscous dampers. Nonlinear dynamic response analyses were conducted on three steel moment-resisting archetype frames of different heights, and incorporating linear and nonlinear viscously damped braces. The FEMA P695 far-field ground motion records set scaled to various intensities were used as seismic input. The main variables investigated in the parametric study included three different target supplemental damping levels, two different distributions of damper properties along the frames' height, and six different nonlinear damper velocity exponents. The numerical results indicate that the inclusion of fluid viscous dampers generally improves the seismic response of the archetype frames. However, the seismic demand on acceleration-sensitive nonstructural components varies significantly depending on the properties of the dampers. For some combinations of dampers' properties, the peak floor horizontal accelerations and floor spectral absolute accelerations in certain nonstructural period ranges can exceed that of the control frames without fluid viscous dampers. These results highlight the limitations of the peak floor acceleration as an engineering demand parameter for acceleration-sensitive nonstructural components
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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