1,720,968 research outputs found
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
Rheological Percolation Threshold in High-Viscosity Polymer/CNTs Nanocomposites
No full textPolystyrene (PS)/multi-walled carbon nanotubes (CNT) nanocomposites have been prepared through melt mixing processing
aiming at obtaining a uniform and homogeneous dispersion of the used nanoparticles within the polymeric matrix. Optical and scanning
electron microscopy has been employed to determine the dispersion and distribution of CNTs at different length scales. Furthermore, the
linear viscoelastic behavior of formulated nanocomposites has been deeply investigated. As a result of CNTs added, the nanocomposites
experience a transition from liquid-like to solid-like rheological behavior, and a disappearance of relaxation processes at low frequency can be
noticed. By plotting G’ versus CNTs loading and fitting with a power-law function, the rheological threshold of PS-based nanocomposites has
been calculated. Moreover, the mechanical behavior of nanocomposites has been investigated and related to the formed CNTs network within
polymer matrix
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
ULTRASONIC WAVES IN HETEROGENEOUS MATERIALS - MECHANICAL CHARACTERIZATION OF HETEROGENEOUS MATERIALS BY MEANS OF ULTRASONIC TESTS AND NUMERICAL MODELS: THE CONCRETE THE CONCRETE
Full text linkThis Ph.D thesis treats the propagation of ultrasonic waves in heterogeneous materials.
It is widely known how waves propagate in homogeneous materials like metallic ones.
But very few aspects are known about the propagation in the heterogeneous materials
because of the complex behavior regarding these materials. The heterogeneity can be
related with the intrinsic properties, elastic and chemical, of each phase of the material,
or with the periodic or random arrangement of inclusions of constant or different
shapes. Concrete is a common case.
In this work the first chapter gives a description of the main characteristics of
heterogeneous materials.. In the second one, the methods of inspection on
heterogeneous materials are presented, and in particular a view on NDT methods is
discussed. The Ultrasonic Wave method is one of the more common NDT methods used
to investigate the inner nature of materials. This method is well established in the
medical field, but more studies are still needed for materials’ science. With the aim to investigate on heterogeneous materials, concrete is considered. In chapter three the
main characteristics of concrete are presented: the chapter discusses about the main constituents, namely aggregates, cements, water and additives. Fresh and hardened phases of concrete are also described. Chapter four presents the theoretical aspect related with the propagation of wave in homogeneous and heterogeneous continuum by
presenting some aspects of micro-structured materials. In chapter four the signal
processing is also presented, and an algorithm to process signals on heterogeneous
materials is discussed. A prototype machine of ultrasonic test developed during the
doctoral studies is presented, and in the last part of the fourth chapter FEM analysis
and laboratory tests are discussed to validate the right working of the instrument Chapter five presents the results of laboratory tests conducted at DICAM department fresh and hardened concrete, and the results of the investigation by mean of ultrasonic tests. Curve of velocity of UW in concrete during the curing time are determined and
related with elastic modules. On hardened concrete, a database of 70 specimen is
created. By using a cluster algorithm the Ultrasonic Test is able to predict the
resistance of concrete with an acceptable level of confidence. A theoretical model is
proposed and validated to explain the value of ultrasonic wave velocity propagating in
heterogeneous media, and a model on resonant frequency is discussed.
In chapter six a multi-scale finite element approach is developed to simulate the
propagation of waves in heterogeneous materials. The model is based on the definition of an elementary cell(representative volume element or RVE) whose equilibrium equation are written based on a mesh-less approach. Follows a procedure that transforms the heterogeneous material in an anisotropic one. The comparison between
numerical simulations conducted by applying heterogeneous models and the multi-scale
mesh-less/FEM model shows a good agreement. Conclusions and future developments
are given in chapter seven.
The author is grateful to the University of Palermo and prof. G. Giambanco for the
great opportunity to develop in this work
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