1,720,958 research outputs found
Influence of particle pre-orientation on elastomagnetic effect in a composite material of ellipsoidal Ni microparticles in a silcione matrix
No full textThe dependence of the elastomagnetic effect on the orientation of Ni ellipsoidal microparticles dispersed in a silicone matrix is investigated. When a volume strain is produced on the composite material in a fixed magnetizing field, the effects of mechanical and magnetic torque are simply modeled and the induced magnetization change can be predicted as a function of the particles' pre-orientation. The theoretical predictions are experimentally verified. As a consequence, it is possible to govern the elastomagnetic effect by proper microparticle orientation
Mechanical vibration sensor based on elastomagnetic composite
No full textA mechanical vibration sensor based on a novel elastomagnetic composite made of magnetic microparticles uniformly dispersed in an elastic non-magnetic matrix is presented. A theoretical model predicting a linear behaviour of the sensor response with the vibration frequency and amplitude is reported. The obtained experimental results are in agreement with the model predictions for magnetic particle volume content lower than 15%. The ability of this kind of sensor to work at low frequencies, where other devices present a lack of reliability, is a very interesting characteristic of this elastomagnetic sensor. (c) 2006 Published by Elsevier B.V
Dynamic response limits of an elastic magnet
No full textThe potential application of an elastomagnetic composite of micromagnets uniformly dispersed into an elastic matrix for mechanical vibrations detections was investigated. The dynamic response of this material is clearly dependent not only on the elastomagnetic coupling but also on the interaction among the microparticles magnetic moments depending on the external applied field. A theoretical simple model, which gives predictions in agreement with the experimental evidences in the range of the linear behavior, is proposed. © 2004 Elsevier B.V. All rights reserved
A novel elastomagnetic composite for vibration attenuation
No full textA new elastomagnetic composite made of alternate layers of magnetic, rigid material and nonmagnetic, elastic one was conceived, produced and studied with the aim of using for the attenuation of spontaneous vibration. The results of the first laboratory tests, performed applying the developed material on a vibrating structure, show the following peculiar characteristics of the novel elastomagnetic composite multilayer: (i) change of rigidity with the vibration magnitude, (ii) vibration attenuation, (iii) shift of the spontaneous vibration frequency of the structure under control. Based on the above-mentioned characteristics, the new composite represents a promising passive element, with auto-adaptive properties, for vibration attenuation
State of the art and development trends of novel nanostructured elastomagnetic composites
No full textThe coupling between elastic and magnetic properties of composite materials made of magnetic particles uniformly dispersed into an elastic matrix was revised. The influence of particles content and size was considered. A unified simple model of the direct and inverse elastomagnetic effect was furnished explaining the experimental results in different experimental conditions. Some applications of elastomagnetic materials in both sensors and actuators are reported and their potentiality is discussed. The correlation between strain and electric conduction in this kind of materials is also presented and the first experimental results on this topic are reported
Novel elastic magnets as actuators core
No full textAn elastic magnet in bar shape, consisting of permanently magnetized Sm2Co7 micro-particles, was produced. The longitudinal strain and/or force amounts given by this novel material under the action of a longitudinal magnetic field are here investigated in order to evaluate the potential applications in very ductile actuator systems
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
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