Fake or real news about COVID-19? Pretrained transformer model to detect potential misleading news

RF inductor power losses of ferrite-free electrode-less low pressure mercury inductively-coupled discharges excited in closed-loop dielectric tube were studied. The modelling was made within the framework of low pressure inductive discharge transformer model for discharge lamps with tubes of 16, 25 and 38 mm inner diam. filled with the mixture of mercury vapour (7.5×10–3 mm Hg) and argon (0.1, 0.3 and 1.0 mm Hg) at RF frequencies of 1, 7; 3.4 and 5.1 MHz and plasma power of (25–500) W. Discharges were excited with the help of the induction coil of 3, 4 and 6 turns placed along the inner perimeter of the closed-loop tube. It was found that the dependence of coil power losses, Pcoil, on the discharge plasma power, Ppl, had the minimum while Pcoil decreased with RF frequency, tube diameter and coil number of turns. The modelling results were found in good qualitative agreement with the experimental data; quantitative discrepancies are believed to be due skin-effect and RF electric field radial inhomogeneity that were not included in discharge modelling.

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A Spam Transformer Model for SMS Spam Detection

IEEE Access ◽

10.1109/access.2021.3081479 ◽

2021 ◽

pp. 1-1

Author(s):

Xiaoxu Liu ◽

Haoye Lu ◽

Amiya Nayak

Keyword(s):

Spam Detection ◽

Transformer Model

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Input Parallel Output Series Structure of Planar Medium Frequency Transformers for 200 kW Power Converter: Model and Parameters Evaluation

Energies ◽

10.3390/en14051450 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1450

Author(s):

Alessandro La Ganga ◽

Roberto Re ◽

Paolo Guglielmi

Keyword(s):

Electric Vehicles ◽

High Performance ◽

Power Converter ◽

Electrical Model ◽

Solid State Transformer ◽

Medium Frequency ◽

Analytical Treatment ◽

Transformer Model ◽

Planar Medium ◽

Parallel Output

Nowadays, the demand for high power converters for DC applications, such as renewable sources or ultra-fast chargers for electric vehicles, is constantly growing. Galvanic isolation is mandatory in most of these applications. In this context, the Solid State Transformer (SST) converter plays a fundamental role. The adoption of the Medium Frequency Transformers (MFT) guarantees galvanic isolation in addition to high performance in reduced size. In the present paper, a multi MFT structure is proposed as a solution to improve the power density and the modularity of the system. Starting from 20kW planar transformer model, experimentally validated, a multi-transformer structure is analyzed. After an analytical treatment of the Input Parallel Output Series (IPOS) structure, an equivalent electrical model of a 200kW IPOS (made by 10 MFTs) is introduced. The model is validated by experimental measurements and tests.

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Inclusion of Neutral Points in Measurement-Based Frequency-Dependent Transformer Model

IEEE Transactions on Power Delivery ◽

10.1109/tpwrd.2021.3098701 ◽

2021 ◽

pp. 1-1

Author(s):

Bjorn Gustavsen

Keyword(s):

Frequency Dependent ◽

Transformer Model

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A nonlinear magnetic circuit model for periodic eddy current problems using T,ϕ-ϕ formulation

COMPEL The International Journal for Computation and Mathematics in Electrical and Electronic Engineering ◽

10.1108/compel-09-2016-0390 ◽

2017 ◽

Vol 36 (3) ◽

pp. 649-664 ◽

Cited By ~ 1

Author(s):

Rene Plasser ◽

Gergely Koczka ◽

Oszkár Bíró

Keyword(s):

Eddy Current ◽

Magnetic Circuit ◽

Iteration Process ◽

Equation System ◽

Circuit Model ◽

Computational Time ◽

Combined Method ◽

3D Fem ◽

Content Type ◽

Transformer Model

Purpose A transformer model is used as a benchmark for testing various methods to solve 3D nonlinear periodic eddy current problems. This paper aims to set up a nonlinear magnetic circuit problem to assess the solving procedure of the nonlinear equation system for determining the influence of various special techniques on the convergence of nonlinear iterations and hence the computational time. Design/methodology/approach Using the T,ϕ-ϕ formulation and the harmonic balance fixed-point approach, two techniques are investigated: the so-called “separate method” and the “combined method” for solving the equation system. When using the finite element method (FEM), the elapsed time for solving a problem is dominated by the conjugate gradient (CG) iteration process. The motivation for treating the equations of the voltage excitations separately from the rest of the equation system is to achieve a better-conditioned matrix system to determine the field quantities and hence a faster convergence of the CG process. Findings In fact, both methods are suitable for nonlinear computation, and for comparing the final results, the methods are equally good. Applying the combined method, the number of iterations to be executed to achieve a meaningful result is considerably less than using the separated method. Originality/value To facilitate a quick analysis, a simplified magnetic circuit model of the 3D problem was generated to assess how the different ways of solutions will affect the full 3D solving process. This investigation of a simple magnetic circuit problem to evaluate the benefits of computational methods provides the basis for considering this formulation in a 3D-FEM code for further investigation.

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