1,720,988 research outputs found
Measurement of nonlinear viscoelastic properties using Dynamic AcoustoElastic Testing : application to cosmetic products
No full textPeu d’outils ont été développés pour le contrôle qualité industriel de textures sur des lignes de production. L’utilisation de techniques sans contact, à base d’ondes acoustiques, présente un avantage évident dans les secteurs agroalimentaire et cosmétique. L’acousto-élasticité dynamique (DAET) est une technique d’interaction entre une onde pompe basse-fréquence de compression/dilatation et une onde sonde ultrasonore, conduisant à l’estimation des propriétés viscoélastiques de la matière. Nous avons développé un modèle décrivant les variations du module viscoélastique : quantification des paramètres non linéaires élastiques (B/A,. C/A...) et visqueux (ωηB/A, ωηC/A...). La méthode DAET et le modèle ont ensuite été validés dans des milieux homogènes (eau, huiles et gels) conduisant à des non-linéarités viscoélastiques faibles (B/A < 15 et (ωηB/A <1). essentiellement liées à la composition du fluide ou un changement d’état. Les résultats les plus probants ont été obtenus dans des milieux granulaires ou constitués d’air (poudres sèches, mousses et billes creuses ): valeurs élevées des non-linéarités viscoélastiques (quadratiques, cubiques). Cette méthode pourra s’avérer être une alternative intéressante à la rhéométrie conventionnelle, en particulier pour la caractérisation de ces fluides complexes.Few tools have been developed for industrial quality control of textures on production lines. The use of contactless techniques. based on acoustic wavcs, offers an obvious advantage in food-processing industry and cosmetics. The dynamic acoustoelastic testing (DAET) is based on the interaction between a low-frequency compressionlexpansion pump wave and an ultrasound probe wave. leading to the quantification of the viscoelastic properties of the matter. We have initially developed a model describing the variations of the viscoelastic modulus: quantification of nonlinear elastic (B/A, C/A...) and viscous (ωηB/A. ωηC/A...) parameters. The DAET method and related model were then validated in homogeneous media (water, oils and gels) leading to low values of viscoelastic nonlineaiities (B/A<15 and ωηB/A<1), essentially governed by the fluid nature or state change. However, the most significant results were obtained in granular or air-based media (dry powder, foam and hollow beads): high values of quadratic and cubic nonlinearities due to microinhomogeneitics. This method appears to be an interesting alternative to conventional rheometry, especially for the characterization of these complex fluids
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
Study of an intra-oral ultrasound system for the detection of periodontal disease
No full textLes maladies parodontales sont des pathologies très répandues qui affectent le parodonte, tissu soutenant les dents. Elles débutent par la gingivite, progressent vers la parodontite et peuvent altérer l’état général du patient. Actuellement, le diagnostic de la maladie n’est pas efficace, long, imprécis et peut être douloureux. Le développement d’un nouvel outil diagnostic est aujourd’hui largement attendu. Dans ce contexte, plusieurs auteurs ont montré que l’échographie haute-résolution peut fournir des informations pertinentes sur le parodonte. Le but de ce travail a été d’élaborer un prototype d’échographe haute-fréquence pour le diagnostic des maladies parodontales. Une nouvelle technologie de fabrication de transducteurs ultrasonores haute-fréquence à base de P(VDF-TrFE) a été évaluée. Elle consiste au dépôt par jet d’encre du matériau piézoélectrique sur un substrat de silicium et a permis la réalisation d’un réseau annulaire HF. Plus globalement, un premier prototype d’échographe a été développé, comprenant une sonde intra-orale avec un système de balayage mécanique du faisceau acoustique et une électronique dédiée. Les performances de ce prototype, notamment du point de vue de la qualité d’image, sont compatibles avec une exploration du parodonte. Des images du parodonte porcin ex-vivo sur tissus sains et pathologiques ont été réalisées.Periodontal diseases are very common pathologies that affect the periodontium, the tissue supporting the teeth. They start with gingivitis, progress to periodontitis and can affect the patient’s general condition. Currently, the diagnosis of the disease is not efficient, long, imprecise and can be painful. The development of a new diagnostic tool is widely expected today. In this context, several authors have shown that high-resolution ultrasound can provides relevant information about the periodontium. The aim of this work was to develop a prototype high-frequency ultrasound machine for the diagnosis of periodontal diseases. A new manufacturing technology for high-frequency transducer technology based on P(VDF-TrFE), was evaluated. It consists of the inkjet deposition of the piezoelectric material on a silicon substrate and has enabled the creation of an HF annular array. More generally, a first prototype ultrasound machine was developed, comprising an intraoral probe with a mechanical scanning system of the acoustic beam and dedicated electronics. The performance of this prototype, especially from the point of view of image quality, is compatible with an exploration of the periodontium. Images of the porcine periodontium ex-vivo on healthy and pathological tissues were produced
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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