I.M.V. Caminiti, A. Formisano, M.C. Lupoli and R. Martone
The purpose of this paper is to propose the optimal allocation and alignment of probes for current distribution measurement (CDM) in the case of twin cable in conduit conductor…
Abstract
Purpose
The purpose of this paper is to propose the optimal allocation and alignment of probes for current distribution measurement (CDM) in the case of twin cable in conduit conductor (CICC) cables with equal and opposite current.
Design/methodology/approach
The most effective approach to CDM in CICC cables is to perform indirect measurements starting from magnetic field map measured externally to the cable. A number of approaches have been proposed to optimize the layout of magnetic field probes external to the cable, but all dealing with single cables. In this paper, an approach to the optimized design of measurement system for twin cables will be proposed, based on the minimization of a suitable cost function.
Findings
A method for the optimal allocation of probes both in terms of rejection of the background field and of condition number of the Green matrix has been defined.
Research limitations/implications
The method is valid only in the hypothesis of linear relationship between currents and magnetic field.
Practical implications
The proposed approach allows to design more robust CDM systems, with increased noise and background field rejection capability.
Originality/value
The problem of optimal design of CDM systems has been previously tackled in literature, but typically with reference to single cables. In the paper, an approach able to explicitly deal with twin cables is proposed.
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Allaeddine Athmani, Saad Grairia, Hatem Seboui, Asma Khemis, Antonio Formisano and Naida Ademovic
The primary goal of this research is to evaluate the seismic performance of Asla Hocine Primary School, a heritage school building in Annaba, Algeria, to prevent additional damage…
Abstract
Purpose
The primary goal of this research is to evaluate the seismic performance of Asla Hocine Primary School, a heritage school building in Annaba, Algeria, to prevent additional damage during future earthquakes in the region. The study aims to guide decision-makers in strengthening weak parts or elements in the building, implementing preventive measures and ultimately reducing earthquake disaster risk by mitigating vulnerability.
Design/methodology/approach
The research employs the 3Muri software to model the seismic behavior and structural failures of the school’s elements. An integrated multimodal pushover analysis is used to generate the non-linear capacity curve of the school to assess its seismic performance. The seismic demand is determined based on Algerian seismic regulations, with peak ground acceleration derived from a probabilistic seismic hazard analysis of Annaba city for return periods of 100, 200 and 500 years. The study develops three seismic scenarios to evaluate performance levels and expected damage probabilities.
Findings
The study reveals that the Asla Hocine Primary School faces a high risk of damage and potential collapse under the expected seismic hazard of the region. The analysis indicates variable resilience across different seismic return periods (100, 200 and 500 years), with the performance level degrading from life safety to collapse prevention and total collapse under increasing seismic intensity. This underscores the need for targeted structural analysis and potential retrofitting to enhance the building’s seismic robustness.
Research limitations/implications
The paper encouraged to account for soil-structure interaction in similar studies, as it can significantly affect the overall seismic performance of buildings. Furthermore, conducting out-of-plane analysis when necessary can offer valuable insights into the structural behavior of specific components.
Practical implications
The insights provided by this study contribute vital data toward conservation efforts and risk mitigation strategies for heritage structures in seismic zones. The findings are intended to guide decision-makers in implementing preventive measures and strengthening weak parts or elements in the studied school building, ultimately reducing earthquake disaster risk by mitigating vulnerability.
Originality/value
This research offers a comprehensive framework for assessing the seismic vulnerability of heritage schools using detailed modeling and analysis. It highlights the importance of considering return periods of seismic events in assessing a building’s seismic performance and provides a deeper understanding of the structural response to seismic stresses at both macrostructural and individual element levels. The study emphasizes the critical need for seismic risk assessment and targeted retrofitting to preserve cultural heritage assets and ensure their continued use.
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Inverse problems are usually ill‐conditioned, requiring the adoption of regularization techniques to obtain reliable results. The choice of the regularization method and of the…
Abstract
Purpose
Inverse problems are usually ill‐conditioned, requiring the adoption of regularization techniques to obtain reliable results. The choice of the regularization method and of the related parameters represents a critical issue that must be based on the knowledge of reliable additional information on the problem. In the paper some possibilities and pitfalls for the choice of regularization strategy are presented and compared.
Design/methodology/approach
Electromagnetic inverse problems (EIP) are usually formulated starting from a direct problem, based on a direct operator, providing the effects (e.g. fields, fluxes) generated by known sources acting through known systems. The direct operators involved in many real world electromagnetic phenomena, due to their compactness, lead to ill posed inverse problems. Inversion procedures pursue the solution regularity through the adoption of various regularization techniques. Improper use of regularizations may unduly constrain the approximated solution and, consequently, cause significant lack of accuracy. Mathematical tools for an effective choice of the regularization technique are not available for every application, and a number of issues are still open. The paper presents a common mathematical model for most of the regularization techniques, discussing their benefits and limitations.
Findings
The paper discusses limits, applicability conditions, and impact on the performance of reconstruction procedures, of some relevant characteristics of the inversion algorithms, with particular reference to robustness against noise and inaccuracies in the system parameters.
Originality/value
Some criteria for an effective application of regularization are also discussed, showing in particular how proper choices, founded on a careful analysis of the direct problem, may reveal quite effective in improving the solution quality.
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Andrea Gaetano Chiariello, Alessandro Formisano and Raffaele Martone
Inductances of complex coils, in the presence of linear materials only, can be computed by discretizing coils into simpler elements, whose magnetic behavior is analytically…
Abstract
Purpose
Inductances of complex coils, in the presence of linear materials only, can be computed by discretizing coils into simpler elements, whose magnetic behavior is analytically expressible, and suitably combining elementary contributions. Reliable results require high numbers of elements. In such cases, advantages can be taken from Graphic Processor Unit (GPU) capabilities of dealing efficiently with high numbers of repeated simple computational tasks. The purpose of this paper is to set up a fast and prompt numerical procedure to cope with the above described task.
Design/methodology/approach
The coils are first decomposed into current segments, taking into account accuracy, relative position and shape of coils to determine the number of segments. An analytical formula is then used to compute elementary contributions using GPUs to speed up the process, and finally superposition is used to recover the result.
Findings
The main advantages of the proposed approach are first demonstrated using simple examples, with analytical solutions, to validate the method accuracy and promptness, then more complex cases are taken to demonstrate its generality.
Research limitations/implications
The method is intrinsically limited by the linearity assumption, excluding the presence of magnetic materials. The adopted formulas require in addition that coils must lie in free space.
Practical implications
The proposed method can help in the design of complex coils or coils systems, where the performance depends on total magnetic energy or magnetic forces among coils.
Originality/value
The paper presents an original implementation in GPU-based computational environment of a procedure to compute inductances, based on the superposition of a high number of current segments. The procedure includes an original method to self-adaptively define number and position of current segments used in the coils discretization.
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P. Bettini, A. Formisano, R. Martone, A. Stella and F. Trevisan
The equivalent currents method has proven to be particularly effective in the identification of plasma boundary in Tokamak fusion devices. Anyway, the ill‐posedness of the…
Abstract
The equivalent currents method has proven to be particularly effective in the identification of plasma boundary in Tokamak fusion devices. Anyway, the ill‐posedness of the mathematical model to be inverted calls for the adoption of suitable regularization techniques to be adopted, in particular to reduce the influence of the measurement errors. In this paper the equivalent currents method is illustrated, together with some details on its application to the plasma identification. In addition, two algorithms for the optimal choice of the representation basis are presented, together with a discussion about the obtained numerical results.
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A. Formisano, R. Martone and F. Trevisan
The applied research in the thermonuclear fusion area is directed towards the design of a commercial reactor. In such a reactor, the room required for the probes deputised to…
Abstract
The applied research in the thermonuclear fusion area is directed towards the design of a commercial reactor. In such a reactor, the room required for the probes deputised to measure the magnetic field for the identification step of the control system must be kept to a minimum, and the number and position of probes must be optimised. A possible approach to the optimal choice of a set of magnetic probes for the reconstruction of a magnetostatic field, based on a statistical approach, is presented and discussed.
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F. Ferraioli, A. Formisano and R. Martone
Electrical resistive tomography (ERT) is a non‐destructive testing technique based upon the reconstruction of the electrical conductivity profile inside a body from measurement…
Abstract
Purpose
Electrical resistive tomography (ERT) is a non‐destructive testing technique based upon the reconstruction of the electrical conductivity profile inside a body from measurement made on its boundary. In the literature about the inverse problems the ERT is considered still challenging being both non‐linear, ill‐posed and very limited in resolution. Purpose of the paper is to assess the performances of an approach exploiting the circuital behaviour of a particular class of problems, highlighting its advantages in terms of simplicity and reduction of the computer burden.
Design/methodology/approach
In this paper, an electrical property of a particular class of problems is pointed out; the same property is used to formulate in terms of a circuital model the ERT problem. The proposed methodology consists basically of combining properly simplified data previously evaluated and collected. The overall procedure is presented with reference to an underground structure diagnostics problem.
Findings
The effectiveness of the proposed approach has been evaluated quantitatively by comparing the simplified procedure results with the ones obtained by performing fully 3D FEM analysis.
Originality/value
The consistently low errors obtained state the convenience of the method also taking into account that the reconstruction process consists merely in post‐processing previously collected data.
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M. Cioffi, P. Di Barba, A. Formisano and R. Martone
This paper seeks to describe an approach to multi‐objective optimization problems (MOOPs) based on game theory (GT) and to provide a comparison with the more standard Pareto…
Abstract
Purpose
This paper seeks to describe an approach to multi‐objective optimization problems (MOOPs) based on game theory (GT) and to provide a comparison with the more standard Pareto approach on a real design problem.
Design/methodology/approach
The GT is first briefly presented, then a possible recasting of MOOPs in terms of GT is described, where players from GT are associated with single objectives and strategies to the choice of degrees of freedom. A comparison with the Pareto approach is performed on the optimized design of a superconducting synchronous generator.
Findings
It was shown that the GT can be applied to the optimized design of real world devices, with results that present a different viewpoint on the problem, yet with device performance comparable with those obtained by standard approaches.
Research limitations/implications
Only the Nash approach to non‐cooperative games has been applied; the conditions for the solution found using GT to belong to the Pareto front have not been fully explored.
Practical implications
Designers and engineers interested in optimal design are presented with a new design technique able to get a balance among conflicting partial objectives, that can also be used to select among different possible designs obtained in other ways (e.g. using the Pareto front approach).
Originality/value
The paper demonstrates the possibility of using GT in the design of real world electromagnetic devices, with reference to the optimal shape design of a high temperature superconducting single‐phase synchronous generator.
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V. Cavaliere, A. Formisano and R. Martone
Magnetic resonance is becoming a routine analysis for many applications. Present day devices include active shielding systems instead of passive ferromagnetic shields. This calls…
Abstract
Magnetic resonance is becoming a routine analysis for many applications. Present day devices include active shielding systems instead of passive ferromagnetic shields. This calls for sophisticated design techniques able to provide satisfactory performance in terms of central field homogeneity, reduced stray field and minimal superconductor’s volume. In the paper some of the possible techniques to deal with such a problem are presented and discussed.
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The problem of reconstructing the current profile in regions not directly accessible by sensors is tackled, with reference to current profile reconstruction in cable in conduit…
Abstract
The problem of reconstructing the current profile in regions not directly accessible by sensors is tackled, with reference to current profile reconstruction in cable in conduit conductors cable. A possible strategy for the choice of the optimal number, location and direction of magnetic probes measuring the field outside the source region is discussed. In addition, some considerations on the related inverse problem resolution are presented.