R. Albanese, G. Rubinacci, A. Tamburrino, S. Ventre and F. Villone
In this paper we present a fast method for the computation of matrix‐by‐vector products arising from the discretization of an integral formulation of the three‐dimensional eddy…
Abstract
In this paper we present a fast method for the computation of matrix‐by‐vector products arising from the discretization of an integral formulation of the three‐dimensional eddy current problem. The approach is based on the distinction between short and long range interactions. The features of the method will be discussed with reference to some numerical examples, also in view of an extension to the nonlinear case of superconductors.
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M. de Magistris, M. Morozov, G. Rubinacci, A. Tamburrino and S. Ventre
The paper aims to apply an innovative inversion method to the problem of imaging (location, direction and size) of concrete rebars by means of eddy current measurements.
Abstract
Purpose
The paper aims to apply an innovative inversion method to the problem of imaging (location, direction and size) of concrete rebars by means of eddy current measurements.
Design/methodology/approach
An accurate numerical model of the probe‐rebar interaction, including eddy currents and skin effect, is considered. The inverse problem is approached with a very efficient inversion procedure previously introduced in a different context.
Findings
A critical analysis of the issues to be considered for the quantitative imaging of rebars is given, and the possibility of relevant simplifications in the numerical model outlined, allowing the development of an accurate and computationally efficient method.
Originality/value
The proposed formulation is applied for the first time to the problem of rebars imaging. Experimental tests have been carried out to validate the numerical model and its underlying hypothesis.
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Our aim is to define a linear ordering of the set of all fuzzy sets in the universal set X, i.e. the set of the whole descriptions on X by means of suitable criteria. Thus it will…
Abstract
Our aim is to define a linear ordering of the set of all fuzzy sets in the universal set X, i.e. the set of the whole descriptions on X by means of suitable criteria. Thus it will be possible to compare different descriptions of the set X by means of interpretations arising from the criteria acting on the set of the predicates on X. In particular, a linear ordering can be obtained in the fuzzy sets via energy functions and entropy functions.
ANTONIO DI NOLA and ALDO G.S. VENTRE
Summary—A synthesis process of a multiple description is defined on a lattice of fuzzy sets which differs from the usual one. Connections between these lattices are stated…
Abstract
Summary—A synthesis process of a multiple description is defined on a lattice of fuzzy sets which differs from the usual one. Connections between these lattices are stated. Mathematical definitions are correlated with concepts of decision and system theory.
Flavio Calvano, Giorgio Dal Mut, Fabrizio Ferraioli, Alessandro Formisano, Fabrizio Marignetti, Raffaele Martone, Guglielmo Rubinacci, Antonello Tamburrino and Salvatore Ventre
– The paper aims to illustrate a numerical technique to calculate fields and inductances of rotating electrical machines.
Abstract
Purpose
The paper aims to illustrate a numerical technique to calculate fields and inductances of rotating electrical machines.
Design/methodology/approach
The technique is based on an integral formulation of the nonlinear magnetostatic model in terms of the unknown magnetization. The solution is obtained by means of a Picard-Banach iteration whose convergence can be theoretically proved.
Findings
The proposed method has been used to build a model of a large turbine generator. In particular, the influence of end effects on flux linkages has been computed. It has been demonstrated that the 2D solution underestimates the flux linkages as well as the no load voltage of 2 per cent, while the leakage fluxes are computed by the 2D solution with errors as high as 20 per cent.
Originality/value
The method is advantageous in comparison to standard methods.
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Lukasz Czarnecki and Delfino Vargas-Chanes
The objective of this chapter is to analyze diabetes onset in Mexico in terms of work relations and family. The authors examined the impacts of diabetes on inequalities, practices…
Abstract
The objective of this chapter is to analyze diabetes onset in Mexico in terms of work relations and family. The authors examined the impacts of diabetes on inequalities, practices of violence among the Mexican population, analyzing gender relations in the context of having diabetes. Our research is based on mixed method approach. First, the authors conducted a survey among 110 diabetic persons in Chiapas and Nuevo León, two Mexican states from the North and the South. Results show that gender violence has impacts in both Mexican states despite of socioeconomical differences. Overall, diabetes is a complex social process that need to be analyzed on different social and socioeconomical levels. Gender violence is a particularly strong factor that has an impact on diabetes. The contribution of this research is based on understanding of diabetes onset as a social construction where gender violence, social cohesion and subjective wellbeing play a significant role in diabetes in the Mexican context. The outcomes of this research might have an impact on transformation of public health policy in Latin America and the Caribbean, from a medical approach to a sociocultural one in terms of diabetes as a chronic illness. Moreover, our results suggest that quality of life depends on the level of interacting within social groups, as diabetes is no longer a disease that affects an individual, but it is more a social phenomenon.
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Raffaele Albanese, Flavio Calvano, Giorgio DalMut, Fabrizio Ferraioli, Alessandro Formisano, Fabrizio Marignetti, Raffaele Martone, Guglielmo Rubinacci, Antonelle Tamburrino and Salvatore Ventre
The purpose of this paper is to present a numerical approach for the computation of 3D magnetic fields in rotating electrical machines. The technique is suitable for the…
Abstract
Purpose
The purpose of this paper is to present a numerical approach for the computation of 3D magnetic fields in rotating electrical machines. The technique is suitable for the computation of flux densities and forces in the end windings of large synchronous turbo generators (TG).
Design/methodology/approach
The magnetostatic FEM model of the generator end windings is carried out for different displacements of the rotor axis to the stator magnetomotive force (MMF) axis. The method is based on a parallel integral formulation allowing to substantially reduce the computational effort.
Findings
The computational model requires only the discretization of magnetic materials and conductors and is fast enough for carrying out 3D analyses on a time scale fast enough for the needs of the designer. As far as the present application is concerned, the analysis of a synchronous generator in the class of 300‐400 MVA has shown that the most stressed elements of the armature conductors are those closer to the stator ends. The study demonstrates that the maximum stress component on the end windings is axial and is achieved when the MMF is aligned to the direct axis.
Originality/value
The present approach combining an efficient integral formulation, the sparsification of the relevant matrices and the parallel implementation of the related algorithms gives rise to an original computational tool that allows a more accurate description of the machine in comparison to other numerical simulations that can be found in the literature.
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Shakespeare's famous line from the play Hamlet focuses our attention on one the most important strategic decisions for most firms today. It's almost as if Shakespeare knew of the…
Abstract
Shakespeare's famous line from the play Hamlet focuses our attention on one the most important strategic decisions for most firms today. It's almost as if Shakespeare knew of the dilemma faced by a company trying to decide whether to participate in today's business to business (B2B) marketplace exchanges. As Prince Hamlet's soliloquy (Hamlet, Act 3, Scene 1) goes:
Y.K. Cheung and V.P. Iu
A simple numerical algorithm is developed for the implementation of the harmonic balance method to analyse periodic responses of a general dynamic system having geometrical…
Abstract
A simple numerical algorithm is developed for the implementation of the harmonic balance method to analyse periodic responses of a general dynamic system having geometrical non‐linearities of the quadratic and cubic types. The resulting non‐linear algebraic equations which are not explicitly determined are solved by non‐linear equation routines available in most mathematical libraries. Various non‐linear responses, such as the combinational resonances of a hinged‐clamped beam, the non‐linear effect on degenerate vibration modes of a square plate and the non‐linear oscillation of thin rings, are presented to demonstrate the versatility of the algorithm.