763 research outputs found

    Mappe di Lavorabilita\u2019 per Giunti Misti di Alluminio Mediante Processo di Saldatura Linear Friction Welding

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    Il Linear Friction Welding \ue8 un processo di saldatura allo stato solido in cui una parte fissa \ue8 forzata contro una parte che si muove con moto lineare alternato per generare calore attraverso l\u2019attrito. Nel presente lavoro viene descritto lo studio effettuato per la realizzazione della giunzione mista mediante processo di Linear Friction Welding tra due leghe di alluminio che presentano propriet\ue0 meccaniche differenti, come la lega AA2011 e AA6082. Lo studio \ue8 stato condotto analizzando due differenti configurazioni determinate dalla posizione relativa delle leghe costituenti i provini da saldare. Per la realizzazione del processo \ue8 stata utilizzata una macchina prototipale dotata di sensori atti alla misura \u201cin process\u201d di variabili fondamentali per la completa comprensione del processo quali temperature nei provini, forze sui provini, accelerazioni e velocit\ue0 che questi subiscono

    RELAP5-3D thermal hydraulic analysis of the target cooling system in the SPES experimental facility

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    The SPES (Selective Production of Exotic Species) experimental facility, under construction at the Italian National Institute of Nuclear Physics (INFN) Laboratories of Legnaro, Italy, is a second generation Isotope Separation On Line (ISOL) plant for advanced nuclear physic studies. The UCx target-ion source system works at temperature of about 2273 K, producing a high level of radiation (10^5 Sv/h), for this reason a careful risk analysis for the target chamber is among the major safety issues. In this paper, the obtained results of thermofluid-dynamics simulations of accidental transients in the SPES target cooling system are reported. The analysis, performed by using the RELAP5-3D 2.4.2 qualified thermal-hydraulic system code, proves good safety performance of this system during different accidental conditions

    Behavioural and biochemical stress responses of Palinurus elephas after exposure to boat noise pollution in tank

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    This study examined the effects of boat noise on the behavioural and biochemical parameters of the Mediterranean spiny lobster (Palinurus elephas).The experiment was conducted in a tank equipped with a video and audio recording system. 18 experimental trials, assigned to boat noise and control conditions, were performed using lobsters in single and group of 4 specimens. After a 1. h habituation period, we audio- and video-recorded the lobsters for 1. h. During the experimental phase, the animals assigned to the boat groups were exposed to boat noise pollution (a random sequence of boat noises). Exposure to the noise produced significant variations in locomotor behaviours and haemolymphatic parameters. Our results indicate that the lobsters exposed to boat noises increased significantly their locomotor activities and haemolymphatic bioindicator of stressful conditions such as glucose, total proteins, Hsp70 expression and THC when tested both singly and in groups. © 2014 Elsevier Ltd

    Imaging of SNR IC443 and W44 with the Sardinia Radio Telescope at 1.5 GHz and 7 GHz

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    Observations of supernova remnants (SNRs) are a powerful tool for investigating the later stages of stellar evolution, the properties of the ambient interstellar medium, and the physics of particle acceleration and shocks. For a fraction of SNRs, multi-wavelength coverage from radio to ultra high-energies has been provided, constraining their contributions to the production of Galactic cosmic rays. Although radio emission is the most common identifier of SNRs and a prime probe for refining models, high-resolution images at frequencies above 5 GHz are surprisingly lacking, even for bright and well-known SNRs such as IC443 and W44. In the frameworks of the Astronomical Validation and Early Science Program with the 64-m single-dish Sardinia Radio Telescope, we provided, for the first time, single-dish deep imaging at 7 GHz of the IC443 and W44 complexes coupled with spatially-resolved spectra in the 1.5-7 GHz frequency range. Our images were obtained through on-the-fly mapping techniques, providing antenna beam oversampling and resulting in accurate continuum flux density measurements. The integrated flux densities associated with IC443 are S_1.5GHz = 134 +/- 4 Jy and S_7GHz = 67 +/- 3 Jy. For W44, we measured total flux densities of S_1.5GHz = 214 +/- 6 Jy and S_7GHz = 94 +/- 4 Jy. Spectral index maps provide evidence of a wide physical parameter scatter among different SNR regions: a flat spectrum is observed from the brightest SNR regions at the shock, while steeper spectral indices (up to 0.7) are observed in fainter cooling regions, disentangling in this way different populations and spectra of radio/gamma-ray-emitting electrons in these SNRs.Comment: 13 pages, 9 figures, accepted for publication to MNRAS on 18 May 201

    Quality of life in spina bifida patients: results of an Italian survey

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    Background The objectives were: 1. to investigate the major topics on the Quality of Life (QOL) of Spina Bifida patients; 2. to evaluate attitudes, the experienced and the behaviours concerning everyday activities, social life participation and familial relationship; 3. to evaluate the information needs; 4. to evaluate the physical and psychological problems related to vesical and intestinal management

    Network Virtual Machine (NetVM): Portabilità ed efficienza nell'elaborazione di pacchetti di rete

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    Un progettista di dispositivi di rete deve affrontare, oltre alle problematiche di prestazioni legate all’aumento della velocità di rete, anche la necessità di aumentare la programmabilità di tali dispositivi al fine di semplificare l’implementazione di applicazioni come, ad esempio, firewall e sistemi per l’individuazione di intrusioni (intrusion detection system, IDS). Questo articolo presenta la nostra attività di progettazione e realizzazione di un network processor virtuale, chiamato NetVM, che dispone di un insieme di istruzioni ottimizzate per l’elaborazione dei pacchetti. La NetVM si prefigge di fornire uno strato di compatibilità per l’elaborazione di pacchetti (come ad esempio il filtraggio, il conteggio, lo string matching) eseguiti da varie applicazioni (firewall, network monitor, IDS) così che possano essere eseguiti da un qualunque apparato di rete, dal costoso router al piccolo dispositivo (come ad esempio uno smart phone). Inoltre, la NetVM permetterà di ottenere in modo efficiente corrispondenza tra le sopracitate funzinoalità di elaborazione di pacchetti e unità hardware specifiche (come ad esempio, ASIC, FPGA, ed elementi per l’elaborazione di rete) presenti in specifici sistemi hardware, come apparati di rete o loro componenti
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