1,720,998 research outputs found
Analysis of AC Losses Due to Current Ripple in MgB Wires With Helicoidal Transformation Method
No full textMagnesium diboride (MgB2) presents a promising solution for efficient, reliable, and cost-effective long-distance direct current (DC) power transmission. Its low cost, high critical temperature (39 K), and compatibility with liquid hydrogen cooling are particularly advantageous. However, High Voltage Direct Current (HVDC) superconducting cables face electrodynamic losses due to current ripples from AC/DC conversion, necessitating meticulous cryogenic system design to mitigate these losses. This study employs Finite Element Method (FEM) analysis to investigate the electrodynamic losses in MgB2 wires under varying current conditions, utilizing a 2D Helicoidal Transformation Method-based model and the open-source solver GetDP. The analysis includes the nonlinear ferromagnetic properties of the wire’s Nickel and Monel matrix, revealing that loss dynamics are significantly influenced by the electromagnetic behavior of the stabilizers. By assessing loss contributions across different materials at operational frequencies typical for DC cables, the study provides insights for optimizing MgB2 superconducting wires in DC power transmission applications
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
Development of an Efficient Simulation Tool for Electromagnetic Analysis of Superconducting Strands
No full textDenne avhandlingen beskriver utviklingen av et simuleringsverktøy for å analysere transiente elektromagnetiske fenomener i superledende ledninger som danner spolene i høyfelts elektromagneter. Arbeidet er gjennomført i rammeverket definert av Finite Element
Quench Simulator (FiQuS)-verktøyet ved CERN, og benytter elementmetoden (FEM)
for å simulere den dynamiske oppførselen til disse lederne under ulike driftsforhold.
Verktøyet bruker en unik todimensjonal metode som reduserer simuleringstiden betydelig sammenlignet med tradisjonelle tredimensjonale FEM-metoder, og gjør det mulig
å analysere ledernes dynamikk under et bredt spekter av forhold.
Simuleringsverktøyet har en modulær oppbygning, med tre hovedkomponenter: en geometrimodul, en mesh-modul og en løsningsmodul. Geometri-modulen genererer modeller
av lederne basert på høynivå inngangsparametere. Mesh-modulen diskretiserer disse
geometriene til finitte elementer og genererer automatisk et mesh som er egnet for
simuleringer. Løsningsmodulen løser det transiente elektromagnetiske problemet ved
bruk av FEM. Alle inngangsparametere er samlet i en enkel YAML-fil, som gjør verktøyet
brukervennlig og tilgjengelig for forskere og ingeniører uten ekspertise innen beregningsmessig fysikk og FEM-simuleringer.
Vi presenterer verktøyets design og implementering, og demonstrerer påliteligheten til
verktøyet ved sammenligning med referanse FEM-modeller. Sammenligningene viser at
verktøyet kan simulere den elektromagnetiske dynamikken til lederne med tilstrekkelig høy nøyaktighet, samtidig som det reduserer beregningskostnadene betydelig sammenlignet med referansemodellene. Deretter presenterer vi potensielle anvendelser av
verktøyet, inkludert analyse av dynamikken til en superleder under ulike forhold og
simuleringer av en spesiell type superledende ledning som ofte brukes i høyfelts MRI magneter.This thesis presents the development of a simulation tool for analyzing small-scale transient electromagnetic phenomena in composite multifilamentary superconducting strands
used in high-field magnets. Conducted within the framework of the Finite Element
Quench Simulator (FiQuS) at CERN, the project leverages the finite element method
to simulate the dynamic behavior of these strands across a range of operating conditions. The tool employs a special two-dimensional approach that significantly reduces
computational cost compared to conventional three-dimensional finite element methods, facilitating parameter sweep studies and analysis of strand behavior under broad
ranges of operating conditions.
The simulation tool features a modular design, comprising three main components: a
geometry module, a mesh module, and a solution module. The geometry module generates models of twisted multifilamentary strands based on high-level input parameters.
The mesh module discretizes these geometries into finite elements, automatically generating meshes suitable for simulations. The solution module solves the transient electromagnetic problem using finite element analysis. All input parameters for the modules
are defined in a single YAML file, making the tool easy to use and accessible to researchers and engineers without expertise in computational physics and finite element
simulations.
After presenting the tool’s design and implementation, we demonstrate its viability by
comparison with reference finite element models. The tool is shown to be capable of
accurately simulating the transient electromagnetic behavior of twisted multifilamentary strands, while significantly reducing computational cost compared to the reference
models. We then illustrate the tool’s capabilities by presenting potential applications,
including the analysis of strand behavior under various conditions and simulations of a
special type of superconducting wire often used in high-field MRI magnets
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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