1,720,971 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
Spectroscopic and chemical characterization of atmospheric plasmas produced in hydrocarbon contaminated air by DC and pulsed corona discharges
No full textOptical emission spectroscopy was used to characterize the plasma produced by DC and pulsed corona discharges in air at ambient pressure in a wire-cylinder reactor. The experiments have been performed both in dry and humid air and also in the presence of n-hexane, used in 500 ppm concentration as a model pollutant. The results provide a thorough characterization of different plasma regimes in terms of electron, vibrational and rotational temperature and are discussed with reference to chemical reactivity data
Use of electrical measurements for non-invasive estimation of plasma electron density in the inductively coupled SPIDER ion source
No full textSPIDER is the full-scale prototype of the ITER Neutral Beam Injector ion source. The plasma heating takes place inside eight drivers via inductive coupling, through the radio frequency (RF) coil. To achieve the optimum conditions during source operation it is necessary to know the plasma behaviour under various operational conditions. One of the essential parameter, is the plasma electron density. It is possible to experimentally measure this parameter, and currently, different methods are being explored, like the estimations coming from the Langmuir probe and optical emission spectroscopy. However, these methods are either available for temporary measurements or require dedicated analyses with large uncertainties. In this perspective, an alternative, reliable, and fast diagnostic tools will be beneficial for the estimation of the order of magnitude of electron density inside the driver. Two models for the estimation of electron density are recalled, discussed, and further modified in this work: one is based on the classical power balance equation and the other is recently described in the literature and relies on classical plasma conductivity. Both models use equivalent electrical parameters of the driver derived from available electrical measurements at the output of the RF generator and through the knowledge of the matching network and the transmission line length. This work explicitly focuses on the application of these models to estimate the plasma electron density in a single driver of SPIDER. Furthermore, the estimations are compared with the first experimental results obtained from temporary electrostatic probe measurements and are found to be in good agreement in terms of magnitude and trends
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
First extraction and acceleration operations of negative ion beams produced in NIO1 experiment
Full text linkThe research and the development of a Neutral Beam Injector as an auxiliary heating system is fundamental for ITER, the experimental reactor under construction in Cadarache (France) as a worldwide collaboration.
This thesis work was performed on NIO1 experiment, developed at Consorzio RFX in collaboration with INFN-LNL. It consists in a radiofrequency negative ion source, with a maximum extracted current of 130 mA in H- ions, accelerated up to 60 kV by a three-grids system and it constitutes the testbed for the source of ITER neutral beam injector.
In this work, the first NIO1 operation with beam extraction is described and analysed, in order to provide a beam characterization, using expecially electrical measurements.
In chapter 1 a brief introduction about fusion physics and ITER is presented, with more emphasis regarding the external heating systems, while in chapter 2 an overview of NIO1 experiment is proposed. The following chapters review the effect of radiofrequency power and gas pressure on total extracted current. The analysis treats separately the current of negative ions and of electrons, extracted from the beam source together with the ions. Operations with oxygen as a filling gas are reported in chapter 3, while hydrogen operations are described in chapter 4. At the end of this chapter a comparison between the two gasses will be performed.
In chapter 5 two ways are used to estimate the electron density: the first is based on a spectroscopical analysis of oxygen-argon emission lines. An alternative method, based on the Langmuir probe physics was developed and a comparison with spectroscopy measurements was performed.
In chapter 6 conclusions are reported.ope
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