2,689 research outputs found

    Low-cost, high-resolution, fault-robust position and speed estimation for PMSM drives operating in safety-critical systems

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    In this paper it is shown how to obtain a low-cost, high-resolution and fault-robust position sensing system for permanent magnet synchronous motor drives operating in safety-critical systems, by combining high-frequency signal injection with binary Hall-effect sensors. It is shown that the position error signal obtained via high-frequency signal injection can be merged easily into the quantization-harmonic-decoupling vector tracking observer used to process the Hall-effect sensor signals. The resulting algorithm provides accurate, high-resolution estimates of speed and position throughout the entire speed range; compared to state-of-the-art drives using Hall-effect sensors alone, the low speed performance is greatly improved in healthy conditions and also following position sensor faults. It is envisaged that such a sensing system can be successfully used in applications requiring IEC 61508 SIL 3 or ISO 26262 ASIL D compliance, due to its extremely high mean time to failure and to the very fast recovery of the drive following Hall-effect sensor faults at low speeds. Extensive simulation and experimental results are provided on a 3.7 kW permanent magnet drive

    Le nuove prospettive strategiche, competitive e manageriali in tema di servizi pubblici locali a rilevanza economica in un contesto in cambiamento

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    The present work aims to analyze the impacts of the new legislative and institutional Italian context for the local utilities, with regard to the governance and management systems for local authorities and local utilities organizations. In particular, there are three different aspects, which are to be studied in depth: the first one considers the consequences of the new institutional context on the governance choices of a local authority towards local utilities organizations, operating on its territory. In this sense, it has been critically considered the strategic positioning possibilities and the options of aggregation, partnership and privatization. The second aspect considers the characters of a consistent strategic and management control system for local utilities organizations. More specifically, it has been analyzed the usefulness of introducing a multidimensional performance measurement system, similarly to the Balanced Scorecard, through four dimensions: qualitative, social, economic and internal processes. Finally, the third aspect considers some relevant ways for financing the mediumlong term investment initiatives. In particular, it has been considered the project financing, with attention to its technical aspects and to the effects of its application on the policies of development for the local utilities organizations.Public Management; Local Utilities; Local Authorities; Governance; Control Systems; Project financing

    Governance of cultural heritage: towards participatory approaches

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    This article analyzes participatory governance in relation to heritage. Based on previous studies on the implementation of participation and theoretical discussions considering the participatory governance of cultural heritage, we found four types of cultural heritage governance, with differing weights with regard to public authorities, civil society, markets, and citizens. Governmental, corporatist, service-led, and cocreative cultural heritage governance types were identified, which reflect the shifts in participatory approaches to governance from state-centered activities to the proliferation of civil society, and from professionally dominated to more citizen-based activities. According to our analysis, culture and heritage can be conceptualized as instruments for the transformation of attributes and competencies, and they work as mediums to cultivate recognition between institutions and citizens. This includes not only seeking consensus in decision making but also respecting the nuances and values of different heritages

    Morphological traits, reproductive and productive performances of Casertana pigs reared outdoors

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    Casertana is an Italian autochthonous pig breed. In the past, the breed was common in Campania and the surrounding area in South Italy because it was valued for its productive performance, particularly regarding the fattening tendency, but in recent decades, autochthonous swine have been replaced by cosmopolitan lean-type pigs and the Casertana breed also experienced a dramatic reduction in numbers. Concern over the preservation of genetic resources and the increased demand for regional food suggest a new way of maintaining the breed. Unfortunately, few recent data on the morpho- logical as well as on the productive traits are available. To ascertain the characteristics of the Casertana breed a pro- ductive trial was performed by comparing Casertana and Large White pure breed and their cross. Sixteen females and 6 males of pure breed Casertana and 18 females and 2 males of pure breed Italian Large White were mated twice to pro- duce Casertana, Large White and Casertana x Large White piglets. The average number of piglets born was significant- ly lower in Casertana gilts, but no difference in the number of weaned piglets among genetic types was observed. Sixty- eight animals of the three genetic types were reared outdoors and received two distinct diets differing in energy content. Pigs were weighted individually every month to calculate average daily gain. Morphological traits of Casertana pigs were also recorded. A total of 54 animals (21 Casertana at 151 kg live weight, 15 crossbreed at 157 kg live weight and 18 Large White at 179 kg live weight) were slaughtered and data on carcasses were collected. Average daily weight gain differed markedly (P< 0.05) among genetic types (450; 552; 695 g/d, respectively for Casertana; Casertana x Large White; Large White) and consequently the slaughter weight also differed. Casertana showed higher dressing percentages that the Italian Large White (P< 0.05). Backfat thickness was also clearly affected by genetic type (P< 0.05): Casertana pigs had the highest value (44.91 mm). The diet had no influence on the average daily weight gain and backfat thick- ness. However, pigs fed with higher energy component had higher (P< 0.05) dressing percentage

    In vivo analysis of staphylococcus aureus-infected mice reveals differential temporal and spatial expression patterns of fhuD2

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    Staphylococcus aureus is an opportunistic human pathogen and a major cause of invasive infections such as bacteremia, endocarditis, pneumonia and wound infections. FhuD2 is a staphylococcal lipoprotein involved in the uptake of iron-hydroxymate and is under the control of the iron uptake regulator Fur. The protein is part of an investigational multi-component vaccine formulation that has shown protective efficacy in several murine models of infection. Even though fhuD2 expression was shown to be upregulated in murine kidneys infected with S. aureus, it is unknown whether the bacterium undergoes increased iron deprivation during prolonged infection. Furthermore, different infection niches of S. aureus might provide different environments and iron availability resulting in different fhuD2 expression pattern within different host organs. To address these questions, we characterized the in vitro expression of the fhuD2 gene and confirmed Fur-dependent iron-regulation of its expression. We further investigated its expression in mice infected with a bioluminescent reporter strain of S. aureus expressing the luciferase operon under the control of the fhuD2 promoter. The emission of bioluminescence in different organs was followed over a seven-day time course, as well as quantitative real-time PCR analysis of the RNA transcribed from the endogenous fhuD2 gene. Using this approach, we could show that fhuD2 expression was induced during infection in all organs analyzed and that differences in expression were observed in the temporal expression profiles, and between infected organs. Our data suggest that S. aureus undergoes increased iron deprivation during progression of infection in diverse host organs and accordingly induces dedicated iron acquisition mechanisms. Since FhuD2 plays a central role in providing the pathogen with the required iron, further knowledge of the patterns of fhuD2 expression in vivo during infection is instrumental in better defining the role of this antigen in S. aureus pathogenesis and as a vaccine antigen

    Eco-innovazione dei processi produttivi: analisi e azioni di intervento per l'efficentamento energetico

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    La crisi congiunturale ha notevolmente appesantito la situazione del Settore della Pesca già strutturalmente difficile. Nel “Rapporto Annuale sulla Pesca e sull’Acquacoltura in Sicilia”, redatto dall’Osservatorio della Pesca, si afferma che “in un contesto prospettico così difficile la quantità di energia specifica, ossia energia consumata per kg di prodotto (kWh/kg di prodotto), necessaria a fornire il prodotto ittico sul mercato deve diventare un indicatore guida per le politiche di ammodernamento ed innovazione. Pertanto è necessaria un’opportuna conoscenza di tutti i consumi energetici necessari per la produzione che, grazie all’utilizzo di pochi e significativi indicatori (quali l’energia per unità di prodotto, la quantità d’acqua per unità di prodotto e le emissioni ed i rilasci inquinanti per unità di prodotto), consenta di descrivere dinamicamente lo stato e la tendenza della filiera ittica”. In tale quadro, è evidente che il fattore energetico rappresenta una componente che ha una rilevante incidenza sulla competitività della Filiera e che, spesso, i vari anelli produttivi “pagano” costi di gestione elevati a causa dell’inefficienza energetica. In un contesto di consumatori sempre più attenti al rispetto ambientale e alla sostenibilità dei prodotti, l’impatto che i sistemi produttivi non efficienti hanno sull’ambiente ha un ritorno negativo anche rispetto all’immagine complessiva della Filiera e dei prodotti: in tal senso, la mancanza di sistemi di gestione ambientale efficaci ed adeguati può risultare, nel lungo periodo, un elemento di penalizzazione sui mercati. Nel progetto “Centro di certificazione e prova del Distretto”, Piani di sviluppo di filiera, linea di intervento: 5.1.1.1 – piano integrato dei servizi comuni, l’attività svolta da questo laboratorio, ECO-INNOVAZIONE DEI PROCESSI PRODUTTIVI, ha lo scopo di calcolare i consumi energetici delle aziende del distretto, prese in esame come campione di studio, e studiare le possibili azioni per ottimizzare, mitigare i consumi e/o l’impatto ambientale come minore emissione di CO2 in atmosfera. Tali attività consentiranno al Distretto, alle sue aziende e tutte le altre aziende del settore di poter conoscere l'energia consumata e quella potenzialmente risparmiata dalle eventuali azioni di efficientamento che saranno proposte da questo gruppo di lavoro

    Diverging effects of postextrasystolic potentiation on left ventricular segmental wall motion in coronary heart disease.

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    The effects of postextrasystolic potentiation (PESP) on regional left ventricular (LV) wall motion were evaluated in 40 coronary artery disease (CAD) patients. Of the 40 CAD patients, 20 had a prior myocardial infarction and 20 had a history of angina pectoris. PESP was obtained by applying programmed atrial stimulation during LV angiography, in a way that basal cycle length, premature beat, and postextrasystolic pause were almost identical in all patients. Segmental wall motion was evaluated by calculating regional ejection fraction (EF) of 5 different areas with a computerized method before and after the premature beat. The results were compared to those obtained in a group of 8 normal subjects. LV areas were classified as normokinetic, mildly hypokinetic, severely hypokinetic, and hyperkinetic, on the basis of their regional EF in respect to normals, and classified as "responder" (R) and "nonresponder" on the basis of the magnitude of the increase of regional EF with PESP. Of a total of 200 areas 129 were normokinetic (68% R), 45 were mildly hypokinetic (78% R), 17 severely hypokinetic (76% R), and 9 were hyperkinetic (78% R). Infarcted patients had a higher percentage of hypokinetic areas in basal conditions (p<0.001), however, the percentage of hypokinetic areas that responded to PESP was not significantly different from noninfarcted patients. In CAD patients, as a whole, a significant direct correlation was found between basal regional EF and regional EF after PESP (r=0.88, p<0.01). In conclusion, the results indicate: (1) normokinetic LV areas do not always respond to PESP; (2) while infarcted patients have a higher proportion of myocardial segments that are hypokinetic, the number of these areas that respond to PESP does not differ between infarcted and noninfarcted patients; (3) in CAD patients there is a direct relationship between the degree of basal regional function and the magnitude of the response to PESP
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