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A Radome device acts as a protective cover to allow the antenna placed inside to work safely under heavy environment conditions, but it should not interfere with the operation of the antenna. The structure of a ceramic nitride (Si3N4) Radome is generally constructed in layers. The parameters that determine the transmission efficiency are: the thickness, the dielectric constant, the structural coefficient and the transmission frequency of the signal f. The model [1] which is at the basis of the probabilistic analysis of the authors, optimizes the transmission efficiency of the radar, finding a series of parameters that determine a transmission efficiency of 70% for each frequency in the range f = 1 ÷ 18 GHz. To do this, the model [1] performs a traditional sensitivity analysis, varying one parameter at a time. The authors, with a new methodology implemented in the instrument Relysoft, making own the equivalent electromagnetic network of the model [1], for each frequency f = 1 ÷ 18 GHz, calculates how the uncertainties values of all parameters influence simultaneously the Transmission Efficiency.

Production of propellant for the return to Earth from in-situ resources allows not transporting the return fuel in space explorations. CO2 from Martian atmosphere may react with H2 to produce methane and water by Sabatier reaction. The activity of Ni (10 wt%) supported on Y2O3-ZrO2, by different preparation methods, was compared. Structural characterization by XRD, TPR and TEM, evidenced that catalytic performances for CO2 methanation mainly depended on the Ni0 particle size and morphology. In particular, the catalyst prepared by wet impregnation with Ni(EDTA)-2 complex, having high nickel dispersion and strong Ni-support interaction, showed remarkable activity, selectivity and stability over time on stream using stoichiometric flow (CO2:H2 = 1:4), appearing like a reliable catalyst for Sabatier process.

In this paper we propose to evaluate the amount of a specific set of pesticides/herbicides from the evaporation or desorption of harmful molecules from the soil. The aim of this work is focused on the definition of reliable pattern that can be detected by disposable gas sensors in order to create a robust gas sensor network for a real time monitoring of vast agricultural areas. As first results we discussed a new automatic procedure for pesticides analysis implemented to define a comparing table to be matched by the as sensors responses. In particular, we analyzed two common pesticides (Chlorpyrifos and Pendimethalin) by measuring their desorption from fibers placed in contaminated soil for different times

Nel campo degli oli extravergini di oliva (EVO), la UE, considerando l’essere umano il giudice ultimo del gusto, prevede un metodo basato su Panel Test che utilizza descrittori secondo il Regolamento n° 2568/91 che quindi assume valore legale. I descrittori sono molti ed hanno a che vedere essenzialmente con il gusto e l’odorato e le metodologie del Panel cercano di evitare le influenze visive, tattili e uditive, soprattutto le prime, attraverso l’uso di contenitori particolari, mentre le altre due, per questo prodotto, risultano ininfluenti, data la sua natura fisica. Procedendo su una strada storicamente ormai ben tracciata della metrologia, considerando i descrittori empirici previsti dalla normativa europea per i Panel Test dell’olio extra vergine di oliva, come troppo lontani da una oggettività scientifica, si cerca di trovarne i componenti più elementari che dovrebbero risultare più facilmente proiettabili su una descrizione numerica oggettiva. La metodologia presa in considerazione dal gruppo di Roma Tre è essenzialmente la gascromatografia cercando di verificare se è possibile costruire campioni depositabili, a partire da set di campioni reali.

Olive Oil is the first food product for which the assessment of the organoleptic quality by means of the Panel Test (PT) was introduced at the level of European Union legislation as a criterion for the sensory evaluation in the Reg. EU 1348/2013 annex XII (revision of Reg. EEC 2568/91). The standard establishes that olive oil must be tasted according to the rigid standards and regulations of the Panel Test (PT) that is carried out by a group of at least 8 professional tasters with a chief, that, through the tasting, give a numerical subjective evaluation (from 0 to 5) to many questions about flavours, in a questionnaire. The ensemble of the scores, reached by each components, defines the organoleptic quality. The amount of these numbers suggests, for better readability, the use of an unsupervised Artificial Neural Network (ANN), which identifies the best two-dimensional representation of the samples that have stimulated the PT. Analysing the coefficients relating a flavour to output neurons of the Kohonen Map, it is possible to individuate the heaviest. If it happens that more heavier coefficients inherent to different flavours, flights the same neuron, an internal correlation will be searched.

La crescente diffusione delle energie rinnovabili (generazione distribuita) e di dispositivi non lineari (inverter, alimentatori switching, ecc…) sta causando problemi significativi sulla rete elettrica, producendo delle variazioni rispetto alle forme d’onda ideali di tensioni e correnti. Ciò può determinare il malfunzionamento, l’accorciamento del tempo di vita o addirittura la rottura di molti apparati sensibili, quindi diventa sempre più indispensabile lo studio della qualità dell’energia elettrica. Alla base di un tale studio è necessaria una prima fase di monitoraggio in modo da raccogliere sufficienti informazioni per poi individuare possibili soluzioni. Inoltre, è interessante osservare come queste variazioni e/o altri eventi transitori si propagano sulla rete elettrica nazionale, ecco quindi la necessità di un monitoraggio distribuito geograficamente. In questo articolo viene mostrato il sistema di monitoraggio della PQ (Power Quality) sviluppato nel Laboratorio di Misure Elettriche ed Elettroniche dell’Università degli Studi “Roma Tre” ed attualmente in uso sul territorio di Roma.

La stima della frequenza fondamentale di un segnale periodico è un tema molto diffuso e di centrale importanza in diversi campi. Ogni segnale periodico è scomponibile in serie di Fourier nel quale la componente a frequenza più bassa è la cosiddetta fondamentale. Tutte le altre componenti avranno una frequenza multipla intera della fondamentale. Per questo motivo ogni segnale periodico può essere rappresentato da un modello multi armonico caratterizzato dalla frequenza fondamentale e dall’ampiezza e la fase di ogni componente armonica. Lo standard IEEE-1057 propone il metodo del sine-fitting a quattro parametri come metodo per la determinazione della frequenza di un segnale periodico campionato. E’ noto però che l’accuratezza di tale metodo basato sul metodo dei minimi quadrati con modello a singolo tono decade all’aumentare della distorsione armonica del segnale analizzato. In letteratura sono state proposte delle versioni multi armoniche di questa tecnica che, sebbene garantisca una maggiore accuratezza presenta due problemi legati alla sua natura ricorsiva: l’eccessiva complessità computazionale e la convergenza non garantita. Questi problemi diventano gravosi quando è necessario ottenere una stima in tempi ridotti per applicazioni real-time.Nell’ambito della Power Quality (PQ) la stima dell’esatta frequenza di rete assume un’importanza centrale sia perché essa stessa è un parametro da monitorare e sia perché la sua conoscenza permette di incrementare l’accuratezza della stima di altri parametri. Nel presente lavoro verrà mostrato un metodo di approssimazione del metodo dei minimi quadrati utilizzando un modello multi armonico. L’applicazione di tale metodo risulta particolarmente conveniente quando le oscillazioni della frequenza sono limitate intorno ad un valore nominale: è il caso della frequenza di rete.

A system based on ZigBee telecommunication mesh wireless network and Raspberry-Pi control card is realized for a complete remote management of an isolate high efficiency street lightning system. The system uses devices and sensors to manage the single street lamppost and to send information by a ZigBee tlc network to a central lamppost equipped with a Raspberry-Pi control Card able to collect and elaborate information. The device allows a remote access through the Web becoming a powerful and complete system able to check the state of the street lamps and allowing appropriately acting in case of failure. The lamp posts are powered by Photovoltaic energy and represents an excellent example of Sustainable Energy paradigm.

Il controllo delle caratteristiche organolettiche per la valutazione della qualità dell’Olio Extra Vergine di Oliva (EVOO) è regolata dalle autorità europee che indicano l'utilizzo del Panel Test (PT). Il PT può essere considerato un vero "sistema metrologico" mentre le percezioni degli assaggiatori sono le sollecitazioni. Questo lavoro ha lo scopo di "disseminare" le proprietà della metrologia rappresentate dal PT per consentire un accesso più abbordabile ad un metodo di valutazione dell’olio altrimenti troppo costoso per le piccole imprese. I risultati del PT vengono impiegati per l’addestramento di una Rete Neurale Artificiale (ANN) non supervisionata. La sintesi è rappresentata su una mappa di Kohonen che rende leggibile i risultati del PT. La disseminazione è ottenuta mediante l’uso dell’algoritmo Back-Propagation su una ANN supervisionata i cui input sono i risultati dell’analisi gascromatografica (GC) di ogni campione di olio e gli output i punteggi ottenuti dal PT. Questa procedura è la "disseminazione della metrologia di uno standard" e anche l'obiettivo del lavoro cioè classificare gli EVOO senza dover sempre ricorrere al PT.

A methodology to enhance the efficiency of avionic measurements through the support of the ASD S3000L database is proposed. This proposal aims to the integration of an expanded FMEA analysis, supported by the S3000L database structure, with the "in field" avionic measurements. This should lead to the reduction of the times and costs involved into failure identification and resolution and should allow the "qualification" of the operator "sensations" and "experiences" for the identification of failures in a complex avionic system.

The Panel Test (PT) is performed by certified assayers and recognized by European Union. From a statistic point of view, it is a methodology sufficiently objective and repetitive so realizing a Metrology. The aim of this work is the study of extra virgin oil olive degradation and stability. The method uses a cascade of two neural networks which inputs are an essential set of quality parameters coming from the Panel Tests made on extra virgin olive oils samples and gas chromatographic analysis on them. Nine extra virgin olive oil samples have been examined. The results of the PT are classified by an unsupervised neural network and related on a Kohonen Map. Then, they are correlated to Gas Chromatographic analysis of olive oil by the Multi Layer Perceptron with Back-Propagation (MLP-BP), a supervised neural network. The MLP-BP is able to classify a sample different from those used for the learning. The olive oil degradation is analyzed by comparing the results on the same sample performed in different periods. Instead, the aromatic stability is observed by comparing different sample from the same producer. The degradation has been observed by the change of the intensity of the signals: the reduction of aromas "fruity" and "green grass" is detected, typical flavors of freshness of the product, in in some oils the flavors "spicy" and "mint" appear. As regards the aromatic stability, many products have maintained the bearing characteristics while the few variations are related to the disappearance of aromas of flowers and/or apple.

In order to provide power quality monitoring activities with metrological certification, a DAS (data acquisition system) has been designed, realized and characterized. The system allows acquisition on tri-phases plus neutral lines picking up 499 samples per period of the fundamental at 50 Hz. To ensure certified measurements, the system gets external certified time and voltage references. The system uses a FTDI Virtual Com Port Driver to communicate data over High Speed RS232 virtual interface and it does not need any advanced programming skill. The choice to use a virtual serial communication makes the data acquisition software portable over many platforms, regardless by the development environment and by the programming language. To test the proposed device some custom software have been written in many programming language (C#, VB6, LabView, MatLab), moreover in order to characterize the device the most common ADC (analog to digital converter) performing test have been applied.

The present invention relates, in general, to analog-to-digital conversion and, in particular, to an analog pre-processing circuit for analog-to-digital converters of a folding type. In particular, the present invention proposes providing an improved analog pre-processing circuit, which exploits devices that are readily available on the market and can be easily manufactured using the integrated technology. The aforesaid aim is achieved by the present invention in so far as it relates to an analog pre-processing circuit for an analog-to-digital converter of a folding type and to n analog-to-digital converter of a folding type, according to what is defined in the annexed claims.

A new inexpensive vineyard protection against hailstorm has been realized and tested. The system has been designed and organized in such a way to perform autonomously local activities to physically control the protection of the vineyard but also to transmit information toward a remote control. Each row has an “umbrella” designed by the authors which, unlike other commercial solutions, protects the product without hindering all the mechanical activities typical of a modern vineyard. Locally the single umbrella uses an electronic card for the management and a ZigBee mesh telecommunication network to transmit data to a central control unit which manages the protection. Because of its efficiency, a Raspberry-Pi control card has been chosen as central unit. Finally, a WiMAX connection was chosen to remotely control the system, thus allowing the authors to overcome distance limitations of commercial Wi-Fi networks. The system has been realized and tested for some months in field also during a hailstorm. The results of these tests proved how the system is easy to use and effectively protects against hail; moreover the authors proved the high reliability of the mechanical components which allow the authors to lower the maintenance costs.

In this article we report the progress made in CO2 sequestration research via formation of. synthetic carbonates and explore the engineering aspects of the proposed methodology. The. approach to synthesize carbonates involves the reaction of a flux of CO2 with Mg-chloride. solution at room temperature. The kinetics of the carbonation reactions demonstrate that: a). in the experiments performed in solutions having both 7 and 16 g L−1 of Mg the rapid. formation of nesquehonite occurred; b) in the experiments with 32 g L−1 of Mg an initial. precipitation of chlorartinite was followed by the formation of nesquehonite and a minor. amount of lansfordite. Carbonation via magnesium chloride aqueous solutions at standard. conditions, here reported, represents a simple and permanent method of CO2 trapping in solid. form. It could be applied at point-sources of CO2 emission and could involve rejected brines. from desalination plants and other saline aqueous wastes. Other various aspects such as the. influence of the salinity of the solution on the efficiency of carbonation and the kinetics of. the reaction are also discussed.

A novel method to synthesize nesquehonite, MgCO3·. 3H2O, via reaction of a flux of gaseous CO2 with Mg chloride solution at ambient conditions, performed using a reactor, is here described. The reaction rate of the process is rapid, with deposition of abundant carbonate in few minutes. The results of a multi-disciplinary methodology, including SEM-EDAX, XRD,. ICP-AES and thermal analysis, suggest that the application of our method at industrial scale can be considered. Moreover, the. possibility to involve in the process saline wastewater as source of. Mg makes the method a promising complementary solution in the sequestration of anthropogenic CO2 at the expense of saline wastewater.

Scopo dell'invenzione è quello di fornire un circuito di pre-elaborazione analogica per convertitori analogico-digitali di tipo folding che sia in grado di alleviare gli svantaggi tipici di questa famiglia. In particolare, la presente invenzione si prefigge di fornire un circuito di pre-elaborazione analogica migliorato che sfrutta dispositivi facilmente reperibili in commercio e facilmente realizzabili in tecnologa integrata.

The article describes the hardware and software of the instrument placed in some European countries able to collect Power Quality (PQ) data. These instruments are provided by one of the bigger UPS farmer in the world. The collected data have been analyzed by Roma Tre University that has elaborated some statistical evaluation of the European PQ. Some economical evaluation on the industrial productivity, connected with the lack of PQ, are also presented. It is also shown a possible creation, in the future, of new corporations able to face PQ problems with the aim to provide new kind of service for those customers particularly sensible to PQ.

Nell'ambito della conservazione dei beni culturali l'accumulo di polveri costituisce un grave problema. Le sue interazioni con i manufatti sono molteplici e i danni che essa può provocare sono notevoli.

In electrical energy power network, disturbances can cause problems in electronic devices therefore their monitoring is fundamental to properly design the protection and compensation devices. In this paper we address the problem of disturbances’ detection by using two different signal processing methods: Wavelets and Hilbert Transform (HT). Methods were tested under different conditions of noise and harmonic distortion (THD) showing the Hilbert Transform can be used as a valid approach for this type of phenomena.

A classification procedure based on timefrequency decomposition of the signal is presented. Parametric spectral ESPRIT method is used for estimation of relevant parameters of signal components and specific areas of the time-frequency plane are chosen, where the signal is expected to show most characteristic patterns. Classification is based on timedomain correlation of reconstructed signals. It is applied to event classification of non-stationary electric signals obtained from a simulated power converter.

Nell'ambito della conservazione dei beni culturali, l'accumulo di polveri costituisce un grave problema. Le sue interazioni con i manufatti sono molteplici e i danni che essa può procurare sono considerevli

In electrical energy power networks, disturbances can cause problems in electronic devices so their monitoring is fundamental in Power Quality. In this paper we address the problem of disturbances estimation by using the Hilbert Transform (HT). It is employed as an effective technique for tracking the voltage waveforms in electrical distribution systems. The mathematical simplicity of the proposed technique, compared with the commonly used algorithms from the literature, renders them competitive candidate for the on-line tracking of disturbances. The accurate tracking of the HT facilitates its implementation for the control of disturbances mitigation devices. Simulation results are provided to verify the tracking capabilities of the algorithm and this has been tested under different conditions: voltage dip with phase jump, noise and frequency changes shows that the Hilbert Transform can be used as a valid methodology for this type of phenomena.