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The concept of self-healed permanent magnet (PM) machines is presented in this article. In order to demonstrate its technical feasibility, the remagnetization behavior of hard ferrite magnets in closed circuit as a function of temperature is initially discussed. Next, the experimental assessment of the remagnetization of engineered parts—with distinct geometry/dimensions from those of the material assessment—installed in an interior PM motor is addressed. Although the concept is agnostic regarding the PM material implemented, this study focused on ferrites since it explores best its benefits due to a unique combination of low criticality of elements, intrinsic physical properties, and cost accessibility.

Among European countries, prevalence rates of extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) are particularly high in those bordering the Mediterranean. This is the case for Italy, with 26% of Escherichia coli displaying resistance to the 3rd generation cephalosporins in 2013. An ESBL-E toolkit designed to assist clinicians in managing patients harboring ESBL-E was favorably implemented in Southern France. In a context of lack of specific Italian recommendations, its extension to an adjacent region of Italy was made possible through a cross-border EU cooperation program. Italian infectious disease (ID) specialists, microbiologists, and community-based general practitioners from three districts in Liguria were offered a toolkit consisting in a warning system and detailed procedures for the management of patients harboring ESBL-E, including seeking advice from an ID specialist, and were trained during 52 video conferences by an experienced French team. Indications and trends in antimicrobial prescription were studied following implementation of the toolkit. Between November 2013 and November 2014, 476 patients were identified as harboring ESBL-E and expert advice was sought for 364 of these; all patients and/or their caregivers were advised on appropriate hygiene measures and 209/341 with documented management received antimicrobial treatment, while asymptomatic carriers (39%) were not prescribed antibiotics. The ESBL-E toolkit was well received by the healthcare staff. A specific, simple tool consisting in a care-bundle approach to manage ESBL-E carriers can restrict antimicrobial prescription to symptomatic patients while raising awareness among caregivers of the importance of seeking expert advice and implementing appropriate hygiene measures.

The massive adoption of electronic converters to supply induction motors leads to critical problems during the normal operation. One of the most investigated problem is the unexpected early failure of the stator winding insulation. When the motors are supplied by electronic converters, the stator insulating system could be subjected to over-voltages due to resonance and reflection phenomena; if these over-voltages exceed the partial discharge inception voltage, partial discharge activity can incept. The erosion of the enamel used to insulate the stator winding wires, due to the presence of partial discharge activity, leads to the degradation of the dielectric characteristics of the insulating system and in the worst cases, to a total breakdown. This investigation campaign presents the outcome of experimental tests aimed at the investigation of the unipolar pulses voltage waveforms role on the degradation of Type I stator winding insulation systems. Induction motors having different insulating systems have been considered. The stator windings have been realized using conventional or corona resistant enameled wires.

Objectives: To estimate the prevalence of and identify risk factors for lipodystrophy syndrome (LS) and body fat abnormality in a population of HIV-infected children and adolescents. Design: Cross-sectional observational study. Methods: HIV-infected subjects aged 2-18 years were recruited from 15 HIV centers in Belgium Italy, and Poland between January 2007 and December 2008. Standardized assessments by the patient's long-term clinician were performed to establish the presence of abnormality. Risk factors were explored in logistic regression models for fat abnormality outcomes and LS (abnormality plus dyslipidemia). Results: Among 426 subjects (70% white), median age was 12.2 years (interquartile range: 9.0-15.0 years) and median duration of antiretroviral therapy was 5.2 years (interquartile range: 2.2-8.8 years). Prevalence was 57% (n = 235) for LS and 42% (n =176) for fat abnormality; 90 subjects with abnormality were affected in ≥3 locations. Lipoatrophy occurred in 28% (n =117) of subjects and lipohypertrophy in 27% (n = 115), most commonly in the face and trunk, respectively. In multivariable analysis, white ethnicity, body mass index, ritonavir/lopinavir, and nonnucleoside reverse transcriptase inhibitors were each associated with an increased risk of LS (P

The adoption of switching electronic converters for squirrel cage motor drives can lead to some critical issues during the normal operation. The early failure of the stator winding insulation is one of the most investigated problems. The cost of motor failure is measured by interruption of plant output as well as extent of repair or replacement. The Surge Test is one of the most important tests for industrial electric motors, insofar as it allows the accurate checking of the machine functionality in order to identify any possible fault in the windings. Surge test is non-destructive and it has to be conducted at test voltage amplitudes so that they do not produce any winding damage and any significant insulation system degradation. This research presents the outcome of an experimental campaign in order to investigate the role of the voltage pulses on the degradation of the stator winding insulation of Type I electric motors: during the study the inter-turn, the groundwall and the phase-phase insulation systems have been taken into account. Electrical aging test have been performed using a surge test waveform at the terminals of the windings. Suitable electrical parameters have been monitored in order to identify the life end conditions. The amplitude of the applied voltage have been varied and the life time values have been collected and analysed. Furthermore the correlation between the repetitive partial discharge inception voltage and the life time has been investigated.

In the present paper a new A, V-A-/spl Psi/ formulation for transient quasi-static eddy current problems using V=0, instead of A/spl middot/n=0, on conductor boundaries is proposed. This choice appears to advantageous for finite element solution problems without any symmetry plane or involving curved boundaries, even though unsuitable if the fields change very slowly. The differential formulation is carefully defined; the ways in which the Coulomb gauge is imposed and the existence and the uniqueness of the solution are discussed. A new method to obtain the symmetry of the final algebraic system is introduced. This symmetrisation technique leads to an indefinite system of algebraic equations with peculiar structure, that led to the development of a special solver. The results are extremely encouraging, the formulation is based on thorough theoretical basis, and it is fairly easy to impose the conditions on conductor boundaries. >

Two strategies for reducing the overall number of finite-element computations needed in an adaptive meshing algorithm are proposed. In the first strategy (called two-threshold refinement), numerical values of the estimated local error are used both to select the elements to be refined and to decide into how may new elements each of them will be subdivided. In the second strategy (called refinement with solution estimation), a solution approximation and its local error on a mesh are estimated from a previous approximation solution. For both methods the required algorithms are presented and the results obtained are compared and discussed. The refinement with solution estimation gives a significant improvement with respect to the usual single threshold refinement method. The two-threshold refinement strategy, even though it has produced errors not always greater than those produced by the single-threshold refinement method, has proven to be worse in general. This result has confirmed the importance of performing Delaunay triangulation each time an element is subdivided. >

This paper presents an original experience in the design of electrical drives. A complete integration has been realised among the design of the motor, power converter and control. This solution became possible thanks to the application of a software tool called Electromechanical System Simulator (EMSS), whose Finite Element Method (FEM) core is Maxwell2D, that allowed the electromagnetic design of the motor and then the generation of a SPICE model of this device so to allow the analysis of the interaction with the power converter and the control structure. This solution presents the interesting aspect of reaching an high detail in the analysis of the electromagnetic field inside the machine without disregarding the circuit-based approach of the converter design.

The increasing performance of simulation platforms coupled to the development of sophisticated numerical analysis tools makes more and more possible an approach to modelling complex electromagnetic devices in an innovative way, alternative to the well consolidated trial and error procedure, based mainly on analytical approaches, experience and prototyping. The design of electromagnetic actuators can be considered an interesting example of how a effective utilization of numerical methods can lead to optimized systems and components. The aim of the present paper is to show how from a simplified simulation model a high accuracy of the final behaviour of a device can be predicted.

The aim of the present paper is to show an interesting approach to the integration process that can be applied to the system simulation of electric motor drives. A comparison with real data from laboratory tests also allows a focus on accuracy. The description is based on a practical authors' experience-a brushless drive with vector control.

This paper presents an original experience in the design of an asynchronous motor featuring some innovative manufacturing solutions. A complete set of three-dimensional transient simulations including the motor and feeding circuit have been carried out, by using a coupled FEM-circuit analysis software tool to verify the potentiality of this solution in comparison with existing motors. This solution presents the interesting aspect of solving together for the electrical and mechanical dynamics, highlighting a whole series of potential problems in the machine's behaviour (torque ripple, current harmonics, etc.). The design of a modern asynchronous motor is a very complex task where simulation plays a very important role, allowing for limitation of prototyping costs and higher performances. This paper presents the activities carried out during the design stages of an innovative motor solution based on the concept of dividing the stator into two main parts: the teeth and the core. A comparison with an existing low voltage standard asynchronous machine has been done and results are presented.

A combined strategy for optimization of electromagnetic devices based on a two-stage scheme is described. Two different ways of implementing a simulated annealing algorithm, one for discrete and one for continuous variables, have been implemented and tested. The second one proved to be more reliable and problem-independent than the other. This technique was used in a combined optimization strategy in combination with a pattern search method. The combined strategy was tested versus analytical and numerical objective functions and showed good behavior, saving, in the best case, up to 70% of the iterations needed for a complete simulated annealing run. The combined strategy was also tested in magnet design problems, with both analytical objective functions and objective functions evaluated by means of finite element codes. The results obtained were encouraging in terms of the objective function values obtained and in the computer time needed. >

As part of the Italian National project on superconductive and cryogenic technologies, the design of superconductive magnets for MHD (magnetohydrodynamic) applications has been carried out. The design of a prototype magnet (active length 2 m) and the conceptual magnetic design of a demonstration magnet (active length 8 m) are reported. The computation techniques used and the optimization procedure developed are described for the set of saddle magnets investigated. The study performed for the prototype has been scaled up to define the basic parameters of the demonstration magnet, and optimization studies have also been performed for this magnet size. Comparisons of results obtained for cylindrical and rectangular saddle magnets, in both sizes, show the possibility of designing magnets meeting design specifications and lead to the choice of the rectangular saddle magnet as the one offering the best performance. >