1,721,528 research outputs found
An ontology-based approach for the instrumentation, control and automation infrastructure of a WWTP
No full textThe instrumentation, control and automation of wastewater treatment plants (WWTPs) is a key aspect to ensure good performance and lower operational costs. However, control systems are seldom interoperable and standard-compliant. In this paper, we propose a knowledge-based approach which decouples the description of the plants and their control strategies from their physical structure and instrumentation. In particular, we propose a semantic model based on ontologies, formalized using the W3C OWL2 standard. We have extended the Semantic Sensor Network and created a specialized representation of the WWTP domain, to provide a consistent description of instrumentation (sensors and probes), actuators and data acquisition systems. We show how this ontology can be used to model typical management actions, such as collecting samples or applying a control policy, and their outcomes
Ghz superconducting single-photon detectors for dark matter search
Full text linkThe composition of dark matter is one of the puzzling topics in astrophysics. To address this issue, several experiments searching for the existence of axions have been designed, built and realized in the last twenty years. Among all the others, light shining through walls experiments promise to push the exclusion limits to lower energies. For this reason, effort is put for the development of single-photon detectors operating at frequencies <100 GHz. Here, we review recent advancements in superconducting single-photon detection. In particular, we present two sensors based on one-dimensional Josephson junctions with the capability to be in situ tuned by simple current bias: the nanoscale transition edge sensor (nano-TES) and the Josephson escape sensor (JES). These two sensors are the ideal candidates for the realization of microwave light shining through walls (LSW) experiments, since they show unprecedented frequency resolutions of about 100 GHz and 2 GHz for the nano-TES and JES, respectively
Il giardino antico da Babilonia a Roma : scienza, arte e natura
No full textDai giardini pensili di Babilonia, una delle sette meraviglie del mondo antico, ai giardini fantastici del mito greco, collocati ai confini del mondo e sede dei più straordinari mirabilia; dal giardino sacro, a margine dei luoghi di culto dove spesso si svolgeva l'attività dei primi medici, agli spazi verdi che in età ellenistica divennero parte integrante di istituzioni per lo studio e la ricerca quali accademie e musei. Infine, gli spazi verdi in epoca romana, sede per la sperimentazione di conoscenze naturalistiche e tecniche
Non-local superconducting single-photon detector
Full text linkWe present and theoretically analyse the performance of an innovative
non-local superconducting single-photon detector. The device operates thanks to
the energy-to-phase conversion mechanism, where the energy of the absorbed
single-photon is transformed in a variation of the superconducting phase. To
this scope, the detector is designed in the form of a double-loop
superconductor/normal metal/superconductors (SNS) Josephson interferometer,
where the detection occurs in a long SNS junction and the read-out is operated
by a short SNS junction. The variation of the superconducting phase across the
read-out junction is measured by recording the quasiparticle current flowing
through a tunnel coupled superconducting probe. By exploiting realistic
geometry and materials, the detector is able to reveal single-photons of
frequency down to 10 GHz when operated at 10 mK. Furthermore, the device
provides value of signal-to-noise ratio up 10^4 in the range 10 GHz-10 THz by
selecting the magnetic flux and the bias voltage. This device can find direct
applications as single-photon detector in both basic science and quantum
technology, while the energy-to-phase conversion mechanism can be at the basis
of non-local read-out and memory architectures for superconducting qubits.Comment: 10 pages, 6 figure
The development of an aged care insurance market in Spain
No full textIn this article, we take a look at the situation of the long-term care insurance market in Spain, where a “dependency law” was passed by the Spanish Parliament in 2006 and implemented in 2007, granting new rights to citizens in need of LTC personal assistance (Guillén and Comas, 2012)
Design and Performance Study of a Micro-Newton Thrust Stand for FEEP
No full textAn increasing number of future space missions and experiments are going to require propulsion systems capable of delivering accurate and finely controllable thrust down to the μN magnitude level, with minimal generation of dynamic noise. FEEP (Field Emission Electric Propulsion) thrusters are ideal candidates for these applications, but they need being accurately characterized in this low-thrust operational range. This article is concerned with assessing the feasibility of the direct laboratory measurement of the FEEP thrust with the required accuracy and with finding solutions to the related problems, namely: • the presence of environmental noise several orders of magnitude stronger than the signal to be measured; • the need to operate the FEEP in high vacuum, while providing the electrical connections to the high voltage supply system. After careful consideration of competing concepts, a homodynamic thrust measurement on a torsion balance with optical read-out has been selected for further analysis. An upper bound of both systematic and repeatability errors was determined and the performance degradation in the presence of environmental dynamic noise was evaluated in terms of attainable signal-to-noise-ratio (SNR) and r.m.s. error on the thrust measurement by means of a nonlinear random vibration analysis of the mechanical system. The results demonstrate the possibility of accurately measuring thrusts down to the μN range, while keeping the system complexity and costs within acceptable limits. Data on the influence of environmental noise from preliminary experiments on a mock-up of the thrust balance confirm the assumptions and predictions of the theoretical model
A gate- and flux-controlled supercurrent diode effect
No full textNon-reciprocal charge transport in supercurrent diodes (SDs) has polarized growing interest in the last few years for their potential applications in superconducting electronics (SCE). So far, SD effects have been reported in complex hybrid superconductor/semiconductor structures or metallic systems subject to moderate magnetic fields, thus showing limited potentiality for practical applications in SCE. Here, we report the design and realization of a monolithic device that shows a valuable SD effect by exploiting a Dayem bridge-based superconducting quantum interference device. Our structure allows reaching rectification efficiencies (η) up to ∼ 6 %. Moreover, the absolute value and the polarity of η can be selected on demand by the modulation of an external magnetic flux or by a gate voltage, thereby guaranteeing high versatility and improved switching speed. Furthermore, our SD operates in a wide range of temperatures up to about 70% of the superconducting critical temperature of the titanium film composing the interferometer. Our SD effect can find extended applications in SCE by operating in synergy with widespread superconducting technologies such as nanocryotrons, rapid single flux quanta, and memories
Brevetto Enea "Gruppo per la gestione automatizzata di impianti per il trattamento biologico di acque reflue. Parte 1. Verifica del funzionamento in campo e rappresentazione della base di conoscenza del dominio
Full text linkIl presente rapporto tecnico introduce Constance - COntrollo iNtelligente e geSTione Automatizzata per il trattameNto di aCque rEflue, un sistema brevettato da ENEA per la gestione intelligente e il controllo automatizzato di impianti di depurazione di acque di scarico, con lo studio di fattibilità e le verifiche di funzionalità effettuate in occasione della sua prima installazione in campo su un impianto di depurazione reale. Principalmente, viene rappresentata la base di conoscenza del dominio operativo, costituita dall’insieme di tutti i segnali acquisiti in campo, le relazioni esistenti tra essi e le elaborazioni necessarie al completo controllo del sistema. Constance utilizza logiche di controllo e politiche di gestione basate su tecniche di machine learning e sistemi a regole, usando unicamente segnali indiretti, quali pH e potenziale redox, misurabili con sensori affidabili ed economici, riducendo i costi di realizzazione e aumentando la robustezza del sistema. Constance garantisce un importante incremento dell’efficienza energetica del sistema di aerazione di oltre il 50% rispetto ad impianti non controllati, mantenendo un’elevata efficienza dei processi biologici, garantendo basse concentrazioni degli inquinanti allo scarico
- …
