1,720,978 research outputs found
Experimental dynamic response of a nonlinear wire rope isolator
Full text linkThe steady-state dynamic response of a structure isolated by a nonlinear wire rope spring operating in the direction of gravity is experimentally studied. The isolated structure consists of two cantilever beams with a lumped mass at the tip. The force-displacement cycles provided by the isolator show a hysteretic behavior due to inter-wire friction and geometric nonlinearities. The restoring force is nonsymmetric exhibiting softening under compression and hardening under tension. The device rheological response is identified using experimental data and a suitable mechanical model. The frequency response curves (FRCs) for increasing levels of the vertical base excitation are obtained for the standalone device, the isolated and non-isolated structure. The expected softening trend of the isolation system and the increase of the displacement amplitude at low frequencies are ascertained both theoretically and experimentally. The comparison between the FRCs of the isolated and the non-isolated structure shows a severe reduction of the transmissibility coefficient in a broad frequency range. This work represents a first step towards the full modeling, validation of the reduced order model of the hysteretic isolator, and the isolated structure towards a full optimization of the device isolation performance
Passive control of a composite laminated truncated conical shell via embedded NiTiNOL-steel wire ropes
No full textA NiTiNOL-steel wire rope is proposed as a nonlinear passive damper to suppress the vibration of a composite laminated truncated conical shell under harmonic and random excitations. The equation of motion of a composite laminated truncated conical shell hosting four NiTiNOL-steel wire ropes is derived from the generalized Hamilton principle and the first-order shear deformation theory under the assumption of small deformation. The restoring and damping force of a NiTiNOL-steel wire rope fitting the parameters identified via the extended Bouc-Wen model is integrated into the equation of motion to generate the overall governing equations. A generalized differential quadrature method is applied to discretize the governing equations into a set of algebraic equations obtained by choosing suitable weight coefficients and grid points coordinates. The discrete equations are solved to obtain the frequency distribution and the associated mode shapes validated via the finite element method. Under harmonic excitations, the resonant peak value and the amplitude reduction rate in the frequency response corroborate the vibration reduction performance of different NiTiNOL-steel wire ropes configurations and found the best type. The effects of different parameters on the vibration reduction performance of different NiTiNOL-steel wire rope configurations are also evaluated. Under Gaussian white noise or colored noise excitations, the limited bandwidth ergodic root means square reveals that the best type under random excitation has the highest probability of realizing the best vibration reduction throughout the entire random process
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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