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Article
Publication date: 1 September 2005

Bernd Flemisch, Barbara Wohlmuth, Francesca Rapetti and Yvon Maday

We present a method for the simulation of the dynamical behavior of a coupled magneto‐mechanical system given in terms of a conductor moving through an electromagnetic field.

Abstract

Purpose

We present a method for the simulation of the dynamical behavior of a coupled magneto‐mechanical system given in terms of a conductor moving through an electromagnetic field.

Design/methodology/approach

For the magnetic part, we consider a model based on an electric vector and a magnetic scalar potential, whereas the mechanical part is modelled by the equation of a rigid body motion. A weak coupling is employed: at each time step the resulting forces are calculated yielding the new displacement of the conductor.

Findings

Numerical results are given for the simulation of an electromagnetic brake with axisymmetric geometry. They indicate that the proposed method is especially well suited for eddy current problems involving moving conductors.

Research limitations/implications

Further research should be undertaken toward the application of the proposed method to real 3D problems.

Originality/value

The spatial discretization of the problem relies on the use of two independent triangulations to approximate the two involved potentials. Whereas the scalar magnetic potential is discretized by means of nodal H1‐conforming finite elements on a grid covering the global computational domain, the vector electric potential is approximated by Hcurl‐conforming edge elements on another grid only covering the conductor. The coupling between the two grids is accomplished via the mortar finite element method. At each time step, only the coupling matrix has to be reassembled, all other involved matrices remain the same. Moreover, no remeshing is necessary when the conductor changes its position. The paper should be valuable for any researcher interested in the numerical simulation of eddy current problems.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 24 no. 3
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 April 1991

K. Horio and H. Yanai

I‐V characteristics of GaAs n‐i‐n structures are calculated by considering impact ionization of carriers. Impact ionization at reverse‐biased n‐i junction becomes a cause…

Abstract

I‐V characteristics of GaAs n‐i‐n structures are calculated by considering impact ionization of carriers. Impact ionization at reverse‐biased n‐i junction becomes a cause of steep current rise when an acceptor density in the i‐layer is high. It is shown that an optimum acceptor density exists to keep a good isolation. Photoconduction transients of GaAs n‐i‐n structures are also simulated, and are shown to be strongly affected by existence of n‐i junctions.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 10 no. 4
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 April 1986

Michal Polácek

In the course of development of human communities towards industrially advanced societies of today, there have been changes not only in economic conditions in the majority…

Abstract

In the course of development of human communities towards industrially advanced societies of today, there have been changes not only in economic conditions in the majority of fields of human activity but also in the ways of providing for food, which went hand in hand with changes in living conditions. Large‐scale industrial production has brought about major changes in the way of life of the population. The development of industrial agglomerations results in a growing number of city dwellers, most of whom have no chance of producing foodstuffs of their own in kind. The distance between residential and industrial areas has been growing, the number of employed women has risen considerably. These are but a few factors affecting the way of boarding, particularly in households.

Details

The Tourist Review, vol. 41 no. 4
Type: Research Article
ISSN: 0251-3102

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Book part
Publication date: 30 December 2013

Guido Erreygers and Roselinde Kessels

In this chapter we explore different ways to obtain decompositions of rank-dependent indices of socioeconomic inequality of health, such as the Concentration Index. Our…

Abstract

In this chapter we explore different ways to obtain decompositions of rank-dependent indices of socioeconomic inequality of health, such as the Concentration Index. Our focus is on the regression-based type of decomposition. Depending on whether the regression explains the health variable, or the socioeconomic variable, or both, a different decomposition formula is generated. We illustrate the differences using data from the Ethiopia 2011 Demographic and Health Survey (DHS).

Details

Health and Inequality
Type: Book
ISBN: 978-1-78190-553-1

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Book part
Publication date: 21 November 2014

Jiti Gao and Maxwell King

This paper considers a class of parametric models with nonparametric autoregressive errors. A new test is established and studied to deal with the parametric specification…

Abstract

This paper considers a class of parametric models with nonparametric autoregressive errors. A new test is established and studied to deal with the parametric specification of the nonparametric autoregressive errors with either stationarity or nonstationarity. Such a test procedure can initially avoid misspecification through the need to parametrically specify the form of the errors. In other words, we estimate the form of the errors and test for stationarity or nonstationarity simultaneously. We establish asymptotic distributions of the proposed test. Both the setting and the results differ from earlier work on testing for unit roots in parametric time series regression. We provide both simulated and real-data examples to show that the proposed nonparametric unit root test works in practice.

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Article
Publication date: 7 November 2016

Juan Wen, Yinnian He and Xin Zhao

The purpose of this paper is to propose a new stabilized finite volume element method for the Navier-Stokes problem.

Abstract

Purpose

The purpose of this paper is to propose a new stabilized finite volume element method for the Navier-Stokes problem.

Design/methodology/approach

This new method is based on the multiscale enrichment and uses the lowest equal order finite element pairs P1/P1.

Findings

The stability and convergence of the optimal order in H1-norm for velocity and L2-norm for pressure are obtained.

Originality/value

Using a dual problem for the Navier-Stokes problem, the convergence of the optimal order in L2-norm for the velocity is obtained. Finally, numerical example confirms the theory analysis and validates the effectiveness of this new method.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 26 no. 8
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 27 August 2019

Bijuan Yan, Huijun Liang, Minjie Jin, Zhanlong Li and Yong Song

In the vibration reduction field, constrained stand-off layer damping cylindrical shell plays an important role. However, due to the lack of accurate analysis of its…

Abstract

Purpose

In the vibration reduction field, constrained stand-off layer damping cylindrical shell plays an important role. However, due to the lack of accurate analysis of its damping characteristics, this hinders its further research and application. Therefore, the purpose of this paper is concerned with an accurate solution for the vibration-damping characteristics of a constrained stand-off-layer damping cylindrical shell (CSDCS) under various classical boundary conditions and conducts a further analysis.

Design/methodology/approach

Based on the Rayleigh–Ritz method and the Hamilton principle, a dynamic model of CSDCS is established. Then the loss factor and the frequency of CSDCS are obtained. The correctness and convergence behavior of the present model are verified by comparing the calculation results with the literature. By using for various classical boundary conditions without any special modifications in the solution procedure, the characteristics of CSDCS with S-S, C-C, C-S, C-F and S-F boundaries are discussed.

Findings

The Rayleigh–Ritz method is effective in handling the problem of CSDCS with different boundaries and an accurate solution is obtained. The boundary conditions have an important influence on the vibration and damping behavior of the CSDCS.

Originality/value

Based on the Rayleigh–Ritz method and Hamilton principle, a dynamic model of CSDCS is established for the first time, and then the loss factor and frequency of CSDCS are obtained. In addition, the effectiveness of adding the stand-off layer between the base shell and the viscoelastic layer is confirmed by discussing the characteristics of CSDCS with S-S, C-C, C-S, C-F and S-F boundaries.

Details

Engineering Computations, vol. 37 no. 1
Type: Research Article
ISSN: 0264-4401

Keywords

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Abstract

Details

Contingent Valuation: A Critical Assessment
Type: Book
ISBN: 978-1-84950-860-5

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Abstract

Details

Economic Growth and Social Welfare: Operationalising Normative Social Choice Theory
Type: Book
ISBN: 978-0-44451-565-0

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Article
Publication date: 17 June 2008

Thomas Walker

We study the relationship between underwriter prestige, family control, and IPO underpricing in an international setting. Data are collected for 5,789 firms that went…

Abstract

We study the relationship between underwriter prestige, family control, and IPO underpricing in an international setting. Data are collected for 5,789 firms that went public across twenty‐five countries between 1995 and 2002. We find that non‐penny‐stock and non‐U.S. IPOs from countries where firms are predominately family‐controlled benefit from associations with well‐known investment bankers; i.e., these firms are less underpriced than similar firms from countries with a low level of family control. At the same time, our findings support prior evidence that suggests that underwriter prestige is positively related to underpricing in the U.S. IPO market. Family‐controlled firms should consider the findings of this study, which identifies factors that are associated with more successful IPO outcomes.

Details

Multinational Business Review, vol. 16 no. 2
Type: Research Article
ISSN: 1525-383X

Keywords

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