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Article

Massimo Fabbri and Antonio Morandi

This study aims to investigate the feasibility of saturated AC heating of magnetic metals. In AC heating of magnetic steel below the Curie temperature, because of the high…

Abstract

Purpose

This study aims to investigate the feasibility of saturated AC heating of magnetic metals. In AC heating of magnetic steel below the Curie temperature, because of the high magnetic permeability, the penetration depth is in the order of 1-6 mm at 50 Hz. Surface heating is then obtained, in practice, if large slabs are processed. The necessity to provide the required surface-to-core temperature uniformity (about 25°C) at the end of the heating process, avoiding excessive thermal stresses which can lead to cracks, thus implies a long heating time.

Design/methodology/approach

The penetration depth can be increased if the material is brought to saturation by applying an external DC magnetic field, and a faster in-depth heating can be obtained. The DC saturating field can be produced with no losses over large volumes by means of superconducting (SC) coils.

Findings

The feasibility of in-depth induction heating of a 200 × 1,000 × 5,000 mm magnetic steel slab with an applied 2 T DC saturating field is numerically investigated. The results show that the use of a DC saturating field leads to shorter processes which fulfil the heating objectives.

Practical implications

A DC saturating field cannot be produced by means of copper coils because of the large amount of material and the unaffordable power required. However, this field can effectively be produced by means of SC magnets based on state-of-the-art materials.

Originality/value

Superconductivity may be the enabling technology for fast and efficient induction heating of magnetic steel slabs if the increase in productivity can balance the additional costs due to the SC magnet.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 36 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

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Article

Massimo Fabbri, Antonio Morandi and Francesco Negrini

To investigate the feasibility of a novel scheme of high‐efficiency induction heater for nonmagnetic metal billets which use superconducting coils.

Abstract

Purpose

To investigate the feasibility of a novel scheme of high‐efficiency induction heater for nonmagnetic metal billets which use superconducting coils.

Design/methodology/approach

The idea is to force the billet to rotate in a static magnetic field produced by a DC superconducting magnet. Since a static superconducting magnet has no losses, the efficiency of the system is the efficiency of the motor used. In order to evaluate the temperature distribution arising from the field profile produced by a given SC coil configuration, a numerical model, based on an equivalent electric network with temperature‐dependent parameters, is developed.

Findings

A substantial independence of the shape of the temperature profile on the angular velocity and the value of the uniform magnetic field applied, is observed. A strong temperature gradient is observed in the radial direction in the proximity of the penetration front and in the axial direction at the top and bottom surface of the billet. Small temperature gradient was observed in the central part of the billet.

Research limitations/implications

The reported temperature profile is inadequate for an actual extrusion process which is desired to happen at a constant temperature. The appropriate profile along the billet length can be achieved by a suitable axial shaping of the magnetic field, through the optimization of the coil layout, whereas the undesired radial gradient can be reduced by interspacing the rotation with temperature smoothing intervals.

Practical implications

The investigation of the profile of applied magnetic field and the heating procedure which allow to achieve the distribution of temperature suitable for the extrusion process can be carried out by using the present model.

Originality/value

A high‐efficiency induction heater for nonmagnetic metal billets using superconducting coils in a novel scheme is investigated.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 24 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

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Article

Massimo Fabbri, Antonio Morandi and Pier Luigi Ribani

To analyse the heating process of an aluminum billet rotating in a static magnetic field produced by superconducting coils.

Abstract

Purpose

To analyse the heating process of an aluminum billet rotating in a static magnetic field produced by superconducting coils.

Design/methodology/approach

The idea is to force the billet to rotate in a static magnetic field produced by a DC superconducting magnet. Since, a static superconducting magnet has no losses, the efficiency of the system is the efficiency of the motor used. In order to evaluate the temperature distribution arising from the field profile produced by a given coil configuration, a numerical model, based on an equivalent electric network with temperature‐dependent parameters, is used.

Findings

The main heating parameters, i.e. heating time, total power injected and temperature difference, are evaluated for different values of angular velocity and magnetic field. The field profile suitable to meet the specifics of an industrial heating process in terms of temperature homogeneity and heating time is determined. Starting form this profile the layout of the magnet is arrived at and some considerations on the operating condition of the superconducting windings are reported.

Research limitations/implications

The mechanical stress in the billet due to weight, centrifugal effects, applied torque and resonance is examined by taking into account the weakening of the material properties with the increase of temperature and the practical limits of the heating process are evaluated.

Practical implications

DC induction heating of aluminum billet using superconducting magnets can be done fulfilling the specifics of the industrial processes.

Originality/value

A high‐efficiency induction heater for aluminum billets using superconducting coils in a novel scheme is investigated.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 27 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

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Article

Massimo Fabbri, Antonio Morandi and Pier Luigi Ribani

The purpose of this paper is to analyse the heating process of an aluminum billet rotating in a static magnetic field produced by optimized supercoducting coils.

Abstract

Purpose

The purpose of this paper is to analyse the heating process of an aluminum billet rotating in a static magnetic field produced by optimized supercoducting coils.

Design/methodology/approach

In order to meet the technical specifications of industrial heating, many processes with low speed in the given high magnetic field have been simulated. The mechanical stresses in the billet are examined by taking into account the temperature dependence of the mechanical properties.

Findings

The main heating parameters, i.e. heating time, average temperature and temperature homogeneity, are evaluated for different values of angular velocity. The simulation results show that an optimal angular speed can be chosen with respect to the heating time.

Research limitations/implications

The mechanical stress in the billet due to weight, centrifugal effects, applied torque and resonance is examined by taking into account the weakening of the material properties with the increase of temperature. The practical limits of the heating process are evaluated; while resonance does not seem to be a concern, the safety against yielding, in order to avoid plastic deformation of the billet during the heating, seems to be a constraint.

Practical implications

DC induction heating of aluminum billet using superconducting magnets can be done fulfilling the specifics of the industrial processes.

Originality/value

The operational and mechanical constraints on a high‐efficiency DC induction heater for aluminum billets using superconducting coils are investigated.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 30 no. 5
Type: Research Article
ISSN: 0332-1649

Keywords

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Article

Roberto Parisini

This paper aims to analyze the problematic relationship between the Left, the commercial revolution and the progressive growth of mass consumption during the Italian…

Abstract

Purpose

This paper aims to analyze the problematic relationship between the Left, the commercial revolution and the progressive growth of mass consumption during the Italian economic miracle.

Design/methodology/approach

Taking for example the city of Bologna, the most important city run by the Italian communist party, the paper problematizes the socio-economic and political – institutional processes connected with the emergence of “American-like” commercial and distribution strategies, and of consumerist identities.

Findings

Bologna’s administrators governed the commerce through a rationalization supported by urban planning, including the establishment of a chain of “associated supermarkets”, built on municipal areas and financed by a mixed-capital company set up for that purpose. At the same time, they sought to protect small retailers to gain their political consensus and to contain crisis-related anxieties among the consumers, a category which has still an uncertain identity in Italy.

Originality/value

Much remains to be seen in the characteristics of the Italian miracle, and in the manner it was ruled. The case of Bologna illuminates an important piece of the Italian Left’s attempt to interpret and to lead the modernization of the country.

Details

Journal of Historical Research in Marketing, vol. 7 no. 1
Type: Research Article
ISSN: 1755-750X

Keywords

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Article

Antonio Giulio de Belvis, Franziska Michaela Lohmeyer, Andrea Barbara, Gabriele Giubbini, Carmen Angioletti, Giovanni Frisullo, Walter Ricciardi and Maria Lucia Specchia

A clinical pathway for patients with acute ischemic stroke was implemented in 2014 by one Italian teaching hospital multidisciplinary team. The purpose of this paper is to…

Abstract

Purpose

A clinical pathway for patients with acute ischemic stroke was implemented in 2014 by one Italian teaching hospital multidisciplinary team. The purpose of this paper is to determine whether this clinical pathway had a positive effect on patient management by comparing performance data.

Design/methodology/approach

Volume, process and outcome indicators were analyzed in a pre-post retrospective observational study. Patients’ (admitted in 2013 and 2015) medical records with International Classification of Diseases, ICD-9 code 433.x (precerebral artery occlusion and stenosis), 434.x (cerebral artery occlusion) and 435.x (transient cerebral ischemia) and registered correctly according to hospital guidelines were included.

Findings

An increase context-sensitive in-patient numbers with more severe cerebrovascular events and an increase in patient transfers from the Stroke to Neurology Unit within three days (70 percent, p=0.25) were noted. Clinical pathway implementation led to an increase in patient flow from the Emergency Department to dedicated specialized wards such as the Stroke and Neurology Unit (23.7 percent, p<0.001). Results revealed no statistically significant decrease in readmission rates within 30 days (5.7 percent, p=0.85) and no statistically significant differences in 30-day mortality.

Research limitations/implications

The pre-post retrospective observational study design was considered suitable to evaluate likely changes in patient flow after clinical pathway implementation, even though this design comes with limitations, describing only associations between exposure and outcome.

Originality/value

Clinical pathway implementation showed an overall positive effect on patient management and service efficiency owing to the standardized application in time-dependent protocols and multidisciplinary/integrated care implementation, which improved all phases in acute ischemic stroke care.

Details

International Journal of Health Care Quality Assurance, vol. 32 no. 3
Type: Research Article
ISSN: 0952-6862

Keywords

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