1,720,963 research outputs found
Interfacial shear rheology study of wet foams
No full textThe texture and the persistence of the wet foam of tiny sphere-shaped gas bubbles that tops the espresso coffee liquid phase are of the utmost importance for the quality of this brew. The prevailing liquid phase of the wet foam solubilizes biopolymers and natural surfactants which will participate to the formation of the liquid films framing the gas phase. The rheology of the interfacial layer can potentially contribute to stability and functionality of foam. This work follows a previous published paper (Piazza, Gigli & Bulbarello, 2007) in which the main macromolecules responsible for the espresso coffee foaming fraction, i.e. proteins/melanoidins complexes fraction and polysaccharides fraction were extracted from defatted and non-defatted commercial coffee powders and analyzed for their foaming attitude and interfacial viscoelastic properties. The development of interfacial viscoelastic dynamic moduli at the liquid/gas interface was monitored by means of a commercial interfacial rheometer. In this paper the rheology data are completed with tensiometric measurements (pendant drop technique) and a mathematical evaluation of the phenomena underlying the viscoelastic properties is suggested. The interfacial elastic modulus increases with time in a sigmoid-like mode and contains the particle coagulation kinetic, governed by Smoluchowsky equation, and the migration of particles from the bulk phase to the interface. Due to the complexity of the system, an appropriate mathematical description is here presented that overcomes some limitations of the existing models and describes the development of interfacial viscoelastic properties at the liquid/ gas interface on long observation scales. The proposed model contains a linear term of transport and the kernel function (considering the simplest case of hard rigid spherical particles in brownian motion), integrated in one differential equation to describe the coagulation and migration of particles to the interface
An inverse analysis procedure for the material parameter identification of elastic-plastic free-standing foils
No full textA model calibration technique is considered for the estimation of material parameters in freestanding thin foils. The experimental apparatus is inspired by bursting strength testers for paper, textile
fabrics and polymer coatings such as geo-membranes. The procedure referred to herein consists of the following phases. A controlled fluid pressure is applied to the foil specimen placed on an horizontal plane with a suitably shaped hole. The induced out-of-plane displacements are measured by a laser profilometer.
The material parameters are then inferred from these measurements through inverse analysis, by simulation of the test and minimisation of a suitable norm which defines the discrepancy between measured and computed displacements. Potentialities and limitations of the proposed method are assessed on the basis of computer-generated “pseudo-experimental” data,
wheremodelling errors are ruled out. The identifiability of some industrially meaningful material parameters is established
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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