Rapporto sullo studio di metodologie innovative di prova per le qualifiche elettromagnetiche, meccaniche e sismiche di componenti e sistemi per le centrali nucleari.

In questo rapporto sono riportati i risultati delle attività svolte dall'unità ENEA UTTMAT-QUAL per l'ottimizzazione dei processi di qualificazione nucleare tramite lo studio e lo sviluppo di metodologie innovative di prova e di integrazione tra prove di tipo e metodo analitico per le qualifiche meccaniche, sismiche ed elettromagnetiche di componenti e sistemi per le centrali nucleari. Nel campo delle prove di compatibilità elettromagnetica (EMC), si è progettata la trasformazione di una camera schermata in camera reverberante destinata all'esecuzione di prove di immunità radiata su sistemi e componenti (parte del processo di qualificazione nucleare), con modalità presumibilmente più severe delle prove eseguite in camera semianecoica. La parte relativa alle qualificazioni meccaniche e sismiche è stata finalizzata allo studio dell'integrazione fra prove di tipo e simulazioni numeriche, utilizzando sistemi innovativi di acquisizione dei dati sperimentali e codici numerici di simulazione meccanica e sismica, ed allo studio dei limiti di applicabilità dei risultati delle analisi numeriche ai processi di qualificazione nucleare su sistemi complessi similari

Qualificazione di sistemi e componenti in ambito nucleare

Il processo di qualificazione nucleare è uno dei principi cardine di progettazione e realizzazione delle centrali nucleari e consiste nel sottoporre tutti i sistemi, i componenti e le strutture rilevanti ai fini della sicurezza nucleare ad un complesso sistema di prove sperimentali, alle specifiche condizioni ambientali dovute ad un incidente o ad uni rischio esterno, per verificare che essi continuino a svolgere le funzioni per le quali sono stati progettati con la massima affidabilità consentendo di mantenere sotto controllo il reattore in qualunque situazione. Il processo è regolato da norme internazionali che prevedono. essenzialmente, quattro metodi generali: prove di tipo, esperienza operativa, analisi, qualificazione combinata. Il metodo con il minor margine di incertezza. adottato nella grande maggioranza dei casi, è il ricorso alle prove di tipo, che implicano la necessità di condurre attività sperimentali di misura e prove in laboratori adeguati. Presso il Centro Ricerche ENEA della Casaccia (Roma) sono concentrati importanti laboratori e infrastrutture sperimentali di prova in cui è possibile condurre l'intero processo di qualificazione nucleare di componenti. dispositivi e sistemi inerenti la sicurezza nucleare: il Laboratorio di Prove Dinamiche ed Ambientali, il Laboratorio di Compatibilità Elettromagnetica, l'Impianto di Irraggiamento Gamma 'Calliope', l'Impianto 'Vapore'. La possibilità di eseguire contestualmente tutte le prove di qualificazione previste dalle norme di sicurezza nucleare costituisce un'interessante opportunità per le industrie italiane che operano nel settore dell'energia nucleare e che potrebbe rilanciarle, con investimenti contenuti, anche nel contesto internazionale. Nel dossier vengono riportate le schede tecniche che descrivono i laboratori e le infrastrutture sperimentali dell'ENEA e delle sue partecipate, le cui competenze possono dare un valido contributo alla qualificazione nucleare. Esse sono state suddivise in due sezioni: nella prima (Qualifiche nucleari) vengono descritti gli impianti direttamente coinvolti nell'esecuzione di misure e prove di qualifica nucleare; nella seconda sezione (Attività a supporto delle qualifiche nucleari

Numerical and experimental comparison among a new hybrid FT-music technique and existing algorithms for through-the-wall radar imaging

A fast low-cost through-the-wall radar imaging (TWRI) system, based on a vector network analyzer (VNA), a couple of switches and an array of Vivaldi antennas, has been designed, realized, and tested. To solve the TWRI inversion problem, an original theoretical modeling for a class of TWRI techniques whose basic functions are the cross-range Fourier transform (FT) of the scattered field and its covariance operator has been proposed. Using these functions, four conventional algorithms, namely the delay and sum (DAS), the FT, the multiple signal classification (MUSIC), the hybrid DAS-MUSIC and a new algorithm, the hybrid FT-MUSIC, have been derived. All these techniques have been implemented and their accuracy and field of view have been tested on canonical scatterers. Then, the algorithms have been applied to measured data collected in different scenarios constituted by a metallic bar or a human subject in the absence and in the presence of a wall between the antenna and the considered targets. Using the proposed TWRI system, it has been possible to detect a subject located up to 5-m away from the radar antenna array through a tuff wall. The proposed FT-MUSIC algorithm has evidenced performances similar to those of the DAS-MUSIC but with significantly lower execution times. Finally, FT-MUSIC performances in terms of field of view and immunity to disturbances are better compared to those of the MUSIC algorithm

Design and Implementation of an Accessible 3D Bioprinter: Benchmarking the Performance of a Home-Made Bioprinter against a Professional Bioprinter

The tremendous application potential of 3D bioprinting in the biomedical field is witnessed by the ever-increasing interest in this technology over the past few years. In particular, the possibility of obtaining 3D cellular models that mimic tissues with precision and reproducibility represents a definitive advance for in vitro studies dealing with the biological mechanisms of cell growth, death and proliferation and is at the basis of the responses of healthy and pathological tissues to drugs and therapies. However, the impact of 3D bioprinting on research is limited by the high costs of professional 3D bioprinters, which represent an obstacle to the widespread access and usability of this technology. In this work, we present a 3D bioprinter that was developed in-house by modifying a low-cost commercial 3D printer by replacing the default extruder used to print plastic filaments with a custom-made syringe extruder that is suitable for printing bioinks. The modifications made to the 3D printer include adjusting the size of the extruder to accommodate a 1 mL syringe and reducing the extruder’s size above the printer. To validate the performance of the home-made bioprinter, some main printing characteristics, the cell vitality and the possibility of bioprinting CAD-designed constructs were benchmarked against a renowned professional 3D bioprinter by RegenHu. According to our findings, our in-house 3D bioprinter was mostly successful in printing a complex glioblastoma tumor model with good performances, and it managed to maintain a cell viability that was comparable to that achieved by a professional bioprinter. This suggests that an accessible open-source 3D bioprinter could be a viable option for research and development (R&D) laboratories interested in pre-commercial 3D bioprinting advancements

Ethnic fragmentation and degree of urbanization strongly affect the discrimination power of Y-STR haplotypes in central Sahel

Y chromosome short tandem repeats (Y-STRs) are commonly used to identify male lineages for investigative and judicial purposes and could represent the only source of male-specific genetic information from unbalanced female-male mixtures. The Yfiler Plus multiplex, which includes twenty conventional and seven rapidly-mutating Y-STRs, represents the most discriminating patrilineal system commercially available to date. Over the past five years, this multiplex has been used to analyze several Eurasian populations, with a reported discrimination capacity (DC) approaching or corresponding to the highest possible value. However, despite the inclusion of rapidly mutating Y-STRs, extensive haplotype sharing was still reported for some African populations due to a number of different factors affecting the effective population size. In the present study, we analyzed 27 Y-STRs included in the Yfiler Plus multiplex and 82 Y-SNPs in central Sahel (northern Cameroon and western Chad), an African region characterized by a strong ethnic fragmentation and linguistic diversity. We evaluated the effects of population sub-structuring on genetic diversity by stratifying a sample composed of 431 males according to their ethnicity (44 different ethnic groups) and urbanization degree (four villages and four towns). Overall, we observed a low discrimination capacity (DC = 0.90), with 71 subjects (16.5 %) sharing 27 Y-STR haplotypes. Haplotype sharing was essentially limited to subjects with the same binary haplogroup, coming from the same location and belonging to the same ethnic group. Haplotype sharing was much higher in rural areas (average DC = 0.83) than urban settlements (average DC = 0.96) with a significant correlation between DC and census size (r = 0.89; p = 0.003). Notably, we found that genetic differentiation between villages from the same country (ΦST = 0.14) largely exceeded that found among countries (ΦST = 0.02). These findings have important implications for the choice of the appropriate reference population database to evaluate the statistical relevance of forensic Y-haplotype matches

The peopling of the last Green Sahara revealed by high-coverage resequencing of trans-Saharan patrilineages

Little is known about the peopling of the Sahara during the Holocene climatic optimum, when the desert was replaced by a fertile environment

A wideband series fed patch array with side lobe level control

In this paper a novel series fed patch array for healthcare radar monitoring applications has been proposed. The antenna is composed of six patches and works in the 5.8GHz Industrial, Scientific and Medical (ISM) band. The shape of the single patch has been designed to overcome two important limitations of this antenna topology: narrow bandwidth and high Side Lobe Level (SLL). To enhance the bandwidth, a dual band structure, obtained by the superposition of two tapered patches with different lengths has been used. For the SLL an innovative technique has been proposed. The amount of power radiated by each patch of the array and one transferred to the following radiating elements are controlled by the curvature degree of the upper hedge of the patch. The designed antenna has a fractional bandwidth of 5.92% (more than twice the available one at 5.8GHz) and a SLL of -21.6 dB at the central frequency. Both the reflection coefficient and the radiation pattern at 5.8GHz have been measured showing a really good agreement with simulation results

A Wideband and Low-Sidelobe Series-Fed Patch Array at 5.8 GHz for Radar Applications

International audienc

Validation and performance analysis of a parallel ported code for simulating the effects of lightning strokes on telecommunication buildings

The Artemis subproject, in the framework of the UE Capri project, deals with porting on parallel architectures of a Method of Moment (MoM) code for electromagnetic design and hardening of telecommunication centres against the effects of lightning strokes. After a preliminary stage of the work during which QR and LU algorithms for large complex matrix inversion were implemented both on Alenia's Quadrics (SIMD) and Cray T3D (MIMD) platforms, in order to choose the best suitable machine for such a kind of problem, the code has been ported on the last one. In this paper the parallel code validation and the performance improvement analysis with respect to the sequential one will be reported and discussed. © 1997 Springer-Verlag Berlin Heidelberg