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Three Dimensional Full Wave Validation of the Maxwell Granet to Debye Model Approach
No full text"The electric properties of a biphasic composite materials are very often described by a Maxwell Garnett model. This model provides the frequency dependent values of an equivalent dielectric constant for the host material containing randomly or aligned distributed inclusions. The frequency dependent electric properties of the equivalent material can be associated to a Debye model suitable for time domain full wave three dimensional electromagnetic simulations. This paper validates the use, in electromagnetic simulations, of the equivalent material described by the Debye model stemming by the Maxwell Garnet one. A biphasic dielectric slab containing randomly distributed inclusions, both dielectric and conductive, is considered. Several configurations with different inclusion distributions are analyzed by a full wave electromagnetic solver and the responses of these biphasic models are compared versus the Debye equivalent one. The Feature Selective Validation technique is used. The frequency limit beyond which the equivalent Debye model does not work accurately is found.
Evaluation of spent coffee grounds as a source of phenolic antioxidants
No full textSpent coffee grounds (SPG), i.e. the solid residue remaining after the production of the beverage, are generated in large amounts by coffee consumption. SPG have no commercial value and are currently disposed of as conventional solid waste or, to a very limited extent, sent to compost facilities. However, the presence in this material of high levels of phenolic compounds with significant antioxidant activity suggests the possibility of using SCG as an inexpensive source of natural antioxidants. In this study we have investigated the feasibility of obtaining a phenolic-rich extract from SPG by an environmentally friendly procedure based on the use of ethanol–water mixtures as the solvent. Total phenols were determined by the Folin-Ciocalteu method and expressed as gallic acid equivalents (GAE), while antioxidant activity was assessed by the DPPH assay. After extraction, the solvent was separated from the solid and vacuum-evaporated to obtain a crude extract which was submitted to analytical determinations. The total amount of phenolics in the waste was in the range of 2000-2500 mgGAE/100 g (dw). The highest extraction yields were achieved by the mixture ethanol-water 60:40 (v/v), which was used to evaluate the influence of temperature (T), extraction time (t) and liquid-to-solid ratio (L/S) on the recovery of phenolics. Under optimal extraction conditions (T = 50-60 °C, t = 30-45 min and L/S = 50-60 mL/g) up to 1800-2000 mg of phenolics per 100 g of dry SCG were obtained. All the extracts were found to possess a high radical scavenging activity
Applying the Analytic Hierarchy Process (AHP) to an FSV Based Comparison of Multiple Data Sets
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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
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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