1,724,964 research outputs found
Optimal resonator damping for wave propagation control in mechanical metamaterials
No full textA novel approach to the optimal damping of linearly damped resonators embedded in metamaterial systems is proposed with the aim of minimizing the metamaterials’ response when the external excitation frequency lies within one of the bandgaps. The equation governing wave propagation in the metamaterial system is obtained via a Galerkin projection combined with the quasi-periodicity ansatz of the Floquet–Bloch theorem. It is shown that an optimality criterion can be obtained for the resonator damping for any excitation frequency by extending the Den Hartog theory of fixed points in the frequency response functions. A numerical example of a honeycomb metamaterial is discussed to show how the proposed method works in a practical application. A full numerical optimization is carried out to study the quality factor of the metamaterials’ response with respect to the resonator damping ratio while proving its effectiveness. © 2023 Elsevier Lt
Ridge-like upwelling in the uppermost lower mantle beneath eastern Africa from finite-frequency seismic tomography
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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
Nonlinear dispersion properties of metamaterial beams hosting nonlinear resonators and stop band optimization
No full textThe nonlinear dispersion properties of a metamaterial beam embedding nonlinear resonators
are investigated. The metamaterial beam incorporates a distributed array of local resonators
exhibiting softening or hardening cubic nonlinearity. The nonlinear dynamic behavior of the
metamaterial beam is first investigated asymptotically via the method of multiple scales, which
yields the closed-form nonlinear dispersion functions with the associated stop bands and the
nonlinear dispersive waves as a combination of acoustic and optical bending waves. The effects
of the resonators nonlinearity and the hosting beam nonlinear bending curvature on the stop
bands are investigated in terms of sensitivity with respect to the strength and type of resonators
nonlinearity. A full multi-variable optimization is carried out to study the nonlinear stop
band size variations with respect to the resonators nonlinearity and the acoustic/optical wave
amplitudes. The results show how the exploitation of the nonlinearities offers great possibilities
to enlarge the size of the stop bands compared to the corresponding linear case and, hence,
greatly enhance the energy absorption bandwidth
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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