1,720,966 research outputs found
FEM ANALYSIS OF ROGOWSKI COILS COUPLED WITH BAR CONDUCTORS
No full textWe study the behavior of Rogowski coils coupled with bar conductors under quasi-static conditions.
Through a finite element (FEM) analysis, we estimate the current distribution across the bar and the flux linked by the transducer for various positions of the primary conductor and for various operating frequencies. Simulation and experimental results are reported in the text
Analysis and Simulation of Rotating Magnetic Field Diffusion through a Parallelogram Hysteresis Model
No full textThis paper deals with the diffusion of rotating electromagnetic fields into hysteretic materials. A simplified vector formulation based
on a parallelogram hysteresis model has been investigated, in order to significantly reduce the computational effort. Vector saturation
and loss properties are discussed. The whole simulation has been done by the use of a finite-element time-domain algorithm
Shielding Effectiveness Measurements for Ferromagnetic Shields
No full textThis paper proposes a new way to measure the shielding effectiveness of ferromagnetic shields. The procedure combines an experimental characterization of the shielding material and numerical simulations. In a first case, magnetic hysteresis is reduced to a series of equivalent B–H linear relations through an optimization procedure that is applied to a measured set of symmetric minor loops, and an equivalent multilayer linear medium is defined through a subsequent iterative procedure. In a second case, magnetic hysteresis is reduced to a simple B–H nonlinear relation, obtaining an equivalent nonlinear shield. In both cases, the obtained results are compared with the direct measurements of the shielding effectiveness at different operating frequencies, showing good agreement and the validity of the proposed method. A comparison and a discussion on the harmonic content of the attenuated field for the investigated shield geometry are reported. The same analysis is carried out for a basic diffusion problem, comparing the results with those obtained by the use of a Preisach model
Analysis and Simulation of Rotating Magnetic Field Diffusion through a Parallelogram Hysteresis Model
No full textShielding Effectiveness Measurements for Ferromagnetic Shields
No full textThis paper proposes a new way to measure the shielding effectiveness offerromagnetic shields. The procedure combines an experimental characterization of the shielding material to a forthcoming numeric simulation. Magnetic hysteresis is reduced to a series of equivalent B - H linear relations through an optimization procedure applied to a measured set of symmetric minor loops. An equivalent multilayer linear medium and a nonlinear shield are defined and adoptedfor calculations. The obtained results are then compared with direct measurements of shielding effectiveness at different operating frequency showing the good agreement and validity of the proposed method. Finally, a comparison and discussion on the harmonic content of the attenuated field is reported
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
Effective magnetic permeability measurement in composite resonator structures
No full textThis paper studies the measurement of magnetism in
composite resonator structures. First, we report the main steps
of a theoretical analysis developed by the authors in a recent
study showing how a composite resonator structure can lead
to obtain unusual magnetic behavior in the low and industrial
frequency ranges. Then, we describe the single unit-cell setup and
the resonator structure adopted for our measurement analysis.
Finally, we analyze the effect of field nonuniformity over the
region of interest and we comment on the measurement of the
effective magnetic permeability in composite media
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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