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This paper describes the operating and technical details of the practical implementation of an innovative time domain reflectometry (TDR)-system for monitoring rising damp in building structures. The proposed system employs wire-like, passive, diffused sensing elements (SE’s) that are embedded, at the time of construction or renovation, inside the walls of the building to be monitored. The SE’s remain permanently inside the wall, ready to be interrogated when necessary.

In questo lavoro vengono presentati il progetto e la caratterizzazione di un sistema in guida d’onda, da utilizzarsi per la misura di permettività di conglomerati bituminosi nell’intervallo di frequenze intorno a 2.45 GHz. Il sistema è stato realizzato in maniera tale da consentire agevolmente la misurazione di sostanze anche di tipo granulare, quali la maggior parte dei componenti di un conglomerato bituminoso. Una serie di test sperimentali su materiali opportunamente scelti ha mostrato incertezze di pochi punti percentuali. Tale dato è stato corroborato anche da un’analisi teorica dell’incertezza di misura. Il sistema, da ultimo, è stato utilizzato per caratterizzare un tipico materiale inerte granulare impiegato nella realizzazione del manto stradale.

Il presente lavoro riguarda l’implementazione di un sistema di monitoraggio dello stato di salute associato al contenuto d’acqua residuo in strutture edilizie basato sulla riflettometria nel dominio del tempo (time domain reflectometry, TDR). Tale sistema prevede che, già in fase di posa in opera della struttura, un elemento sensibile (ES) bifilare a bassissimo costo (simile a quello impiegato in altri lavori scientifici dagli autori per la localizzazione di perdite in condotte idriche interrate) sia inglobato all’interno della struttura.

È stato messo a punto e validato attraverso un’ampia campagna di test, un innovativo sistema per la ricerca perdite in condotte idriche e fognarie fatte in qualunque materiale. I risultati ottenuti dimostrano che il sistema permette di individuare con un’elevata accuratezza la posizione della perdita. Un grosso vantaggio del sistema proposto è che non ha limiti di impiego per quanto riguarda il materiale o i diametri delle condotte; pertanto, è adatto per ispezionare condotte interrate fatte di qualsiasi materiale, sia idriche che fognarie.

È stato presentato un sistema per la misura di livelli in serbatoi basato sulla tecnica TDR. Il sistema proposto può essere impiegato per il monitoraggio di serbatoi fatti in qualunque materiale, di forme particolari e alti anche decine di metri. Inoltre, il fatto che il sistema fornisce misure in tempo reale e che può essere controllato da remoto, lo rende particolarmente attraente per applicazioni industriali.

The present chapter describes some of the most promising applications of microwave reflectometry (MR) for monitoring and sensing purposes in the agrofood industry. The present chapter focuses on three specific applications in which MR is employed for monitoring purposes in the agrofood industry. In particular, the following applications are considered: 1. Moisture measurement of granular agrofood materials; 2. Quality control of vegetable oils; 3. Monitoring of dehydration process of fruit and vegetables.

Apparatus and relevant methodology for the individuation and detection of leaks (of water or, more in general, of other fluids) and faults, in underground pipes, through the adoption of a system based on microwave reflectometry.

The mobile phone market has experienced an exponential growth trend in the last ten years. Europe continues to be the main market in the developed countries, although in the last two years growth has witnessed a slow-down. Despite being already a mature market, Italy has a “penetration rate” (i.e., the number of active lines per 100 inhabitants) higher than 146, the highest in the European Union. Furthermore, in Italy about 70% of active lines use UMTS and HDSPA, the so-called 3G and 3,5G technologies, where G stands for Generation. It is important to point out that despite their higher power levels allowing faster data transmission and the use of increasingly complex services and software, these technological standards are high energy consuming. This scenario has suggested a study on the energy consumption of mobile phones and their associated equipment. The aim of the present article is to estimate the impact of this sector (including the so-called mobile network) on the Italian energy consumption

Sistema per la ricerca perdite in condotte idriche e fognarie interrate

In this paper, a time domain-based approach to practical characterization of antennas is presented. The goal is to prove that time domain-based approach, after appropriate processing, represents an accurate and more practicable alternative to the typically used (yet highly expensive) antenna characterization measurements that are performed in anechoic chamber through a Vector Network Analyzer (VNA). To this purpose, two commercial antennas, differing in operating frequency band, are considered as significant test-cases. Reflectometric measurements performed in Time Domain (TD) are subsequently transformed in Frequency Domain (FD), and compared with VNA reference measurements directly obtained in anechoic chamber. Results demonstrate that the preliminary choice of an optimal time window is the main factor leading to a substantial enhancement of the overall measurement accuracy, which is comparable to that provided by VNA measurements in anechoic chamber. This demonstrates that a good insight into the antenna characteristics can be obtained even without using highly expensive facilities.

In this paper we describe the characterization of a family of optical devices based on heterojunction and heterodimensional structures and we investigate their static and dynamic properties. Such devices are good candidates, due to their high performance, for utilization as the sensing element for the realization of sensors in the fields of telecommunications, remote sensing, LIDAR and medical imaging. First, we present a Heterostructure Metal- Semiconductor-Metal (HMSM) photodetectors that employ a uniformly doped GaAs/AlGaAs heterojunction for the dual purpose of barrier height enhancement and creating an internal electric field that aids in the transport and collection of the photogenerated electrons. In this first family of devices, two doping levels are compared showing the direct effect of the aiding field due to modulation doping. Subsequently, we analyse a novel Resonant-Cavity- Enhanced (RCE) HMSM photodetector in which a Distributed Bragg Reflector (DBR) is employed in order to reduce the thickness of the absorption layer thus achieving good responsivity and high speed as well as wavelength selectivity. Current-voltage, photocurrent spectra and highspeed time response measurements point out the better performance of this last family of detectors, as they can operate in tens of Giga-Hertz range with low dark current and high responsivity. Particularly, the I-V curves show a very low dark current (around 10 picoamps at operative biases) and the photocurrent spectrum shows a clear peak at 850 nm wavelength. Combination of very low dark current wavelength selectivity, and compatibility with high electron mobility transistors makes these devices especially suitable for the above-mentioned applications.

Crete, Greece

COVID-19 is an ongoing global pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. Although it primarily attacks the respiratory tract, inflammation can also affect the central nervous system (CNS), leading to chemo-sensory deficits such as anosmia and serious cognitive problems. Recent studies have shown a connection between COVID-19 and neurodegenerative diseases, particularly Alzheimer’s disease (AD). In fact, AD appears to exhibit neurological mechanisms of protein interactions similar to those that occur during COVID-19. Starting from these considerations, this perspective paper outlines a new approach based on the analysis of the complexity of brain signals to identify and quantify common features between COVID-19 and neurodegenerative disorders. Considering the relation between olfactory deficits, AD, and COVID-19, we present an experimental design involving olfactory tasks using multiscale fuzzy entropy (MFE) for electroencephalographic (EEG) signal analysis. Additionally, we present the open challenges and future perspectives. More specifically, the challenges are related to the lack of clinical standards regarding EEG signal entropy and public data that can be exploited in the experimental phase. Furthermore, the integration of EEG analysis with machine learning still requires further investigation.

Type 1 diabetes (T1D) is an autoimmune disease that affects millions of people worldwide. A most challenging aspect regarding diabetes therapy is the way to calculate the insulin bolus amount to inject before meals. The artificial pancreas (AP), combining both blood glucose monitoring and automatic insulin delivery, has demonstrated its effectiveness in T1D treatment. However, one of the limitations of current AP devices is the fact that the patient needs to insert manually the amount of insulin to be released and the bolus is calculated on the estimated carbohydrate intake, while other nutritional factors of the patient's meal are not taken into account. To overcome this issue, in this paper, two innovative algorithms to predict the postprandial blood glucose concentration after the meal in T1D patients on AP systems are presented. The proposed algorithms, which cover a time span of prediction of 180 minutes, take into account not only the carbohydrates amount in the meal but also other selected nutritional factors. More specifically, the proposed algorithms are based on feed forward multi-layer neural networks (FFNNs) and long short-term memory networks (LSTMNs) with a specific hyper-parameter configuration. The output of the proposed architectures consists of a predicted glycemic curve. The algorithms were validated by comparing the predictions of the networks performed on a test dataset with the measured glycemic values recorded by the hybrid closed-loop systems worn by the patients.

Soil monitoring is a key topic from several perspectives, such as moisture level control for irrigation management and anti-contamination purposes. Monitoring the latter is becoming even more important due to increasing environmental pollution. As a direct consequence, there is a strong demand for innovative monitoring systems that are low cost, provide for quasi-real time and in situ monitoring, high sensitivity, and adequate accuracy. Starting from these considerations, this paper addresses the implementation of a microwave reflectometry based-system utilizing a customized bifilar probe and a miniaturized Vector Network Analyzer (m-VNA). The main objective is to relate frequency-domain (FD) measurements to the features of interest, such as the water content and/or the percentage of some polluting substances, through an innovative automatable procedure to retrieve the Debye dielectric parameters of the soil under different conditions. The results from this study confirm the potential of microwave reflectometry for moisture monitoring and contamination detection.

The aim of this work is to propose two different and complementary sensors for the structural health monitoring of concrete beams. In particular, a diffused sensing element and a split ring resonator network are presented. The first sensor is able to detect the variation of the dielectric properties of the concrete along the whole beam length, for a diffuse monitoring both during the important concrete curing phase and also for the entire life cycle of the concrete beams. The resonators instead work punctually, in their surroundings, allowing an accurate evaluation of the permittivity both during the drying phase and after. This allows the continuous monitoring of any presence of water both inside the concrete beam and in points that can be critical, in the case of beams in dams, bridges or in any case subject to a strong presence of water which could lead to deterioration, or worse, cause serious accidents. Moreover, the punctual sensors are able to detect the presence of cracks in the structure and to localize them.

Pest management is looking for green and cost-effective innovative solutions to control tiger mosquitoes and other pests. By using biomimetic principles and biocompatible/biodegradable biopolymers, it could be possible to develop a new approach based on substrates that selectively attract insects by reproducing specific natural environmental conditions and then kill them by hosting and delivering a natural biopesticide or through mechanical action (biomimetic lure and kill approach, BL&K). Such an approach can be theoretically specialized against tiger mosquitoes (BL&K-TM) by designing hydrogels to imitate the natural oviposition site’s conditions to employ them inside a lure and kill ovitraps as a biomimetic oviposition substrate. In this work, the hydrogels have been prepared to prove the concept. The study compares lab/on-field oviposition between standard substrates (absorbing paper/masonite) and a physical and chemically crosslinked hydrogel composition panel. Then the best performing is characterized to evaluate a correlation between the hydrogel’s properties and oviposition. Tests identify a 2-Hydroxyethylcellulose (HEC)-based physical hydrogel preparation as five times more attractive than the control in a lab oviposition assay. When employed on the field in a low-cost cardboard trap, the same substrate is seven times more capturing than a standard masonite ovitrap, with a duration four times longer.

Most sensing networks rely on punctual/local sensors, thus lacking the ability to spatially resolve the quantity-To-be-monitored (e.g., a temperature profile, a humidity profile, etc.) without relying on the deployment of numerous inline sensors. At the state of the art, most quasi-distributed or distributed sensing technologies rely on the use of optical fiber systems; however, these are generally expensive and this limits their large-scale adoption. On the other hand, recently, elongated sensing elements have been successfully used with time-domain reflectometry (TDR) for implementing diffused monitoring solutions. The advantage of TDR is that this is a relatively low-cost technology, with adequate measurement accuracy and the potential to be customized to suit the specific needs of different application contexts of the 4.0 Era. Starting from these considerations, this paper addresses the design, implementation and experimental validation of a novel generation of elongated sensing element networks (SENs) that can be permanently installed in the systems to be monitored and used for obtaining the diffused profile of the quantity-To-be-monitored. In particular, as case studies, three applications are considered: monitoring irrigation process in agriculture (SEN-A, agriculture); leak detection in underground pipes (SEN-W, water); and monitoring of building structures (SEN-B, building).

Measuring moisture content in building materials is essential both for professional practice and for research. However, this is a very complex task, especially when long-term minor destructive measurements are desired. The time-domain reflectometry (TDR) technique is commonly used for soil moisture measurements, but its application in construction materials is considered a relatively new method, particularly for low-porosity building materials. The major obstacles to its current use in construction materials are (1) the difficulty of ensuring good contact between the TDR probe and the material, and (2) the lack of appropriate conversion functions between the measured relative permittivity and the moisture content of building materials. This paper intends to contribute to overcoming these difficulties by explaining in detail all the required steps to monitor moisture content in real-scale limestone walls. For that, a device is presented to guarantee the correct installation of the TDR probes on the walls, and a calibration procedure through the gravimetric method is proposed to avoid the use of an unsuitable calibration function developed for soil moisture measurements. In addition, the importance of the individual probe calibration is discussed, as well as TDR advantages and disadvantages for construction materials. The results obtained so far reveal that the TDR technique is suitable to detect moisture content variations in limestone, which is a low-porosity building material. (c) 2020 by the authors.

It is known that bi-wires can be employed as passive distributed sensing elements (SEs), to accurately locate water infiltrations in soil, concrete materials, and so on, using the standard time-domain reflectometry instrumentation and proper signal processing. This paper examines the possibility of using the same kind of SEs with simpler techniques and cheaper hardware, in order to trigger an alert in the case of water infiltrations. Two techniques are examined: the first measures the SE capacitance, and the second measures the time-of-flight of electromagnetic waves in the SE. The performance of the techniques is comparatively evaluated, in terms of sensitivity to the presence of water and the influence of temperature variations. The capacitance-based technique is found to be more sensitive to the presence of water, but also more prone to the influence of temperature, as long as the temperature variations are of modest entity (below 10 °C). For higher temperature variations, the capacimetric method appears to be advantageous. The results of this paper are useful to practically implement the monitoring of water leaks in a large set of buried pipes, water infiltrations in a large concrete structure, and so on.

In the last twenty years, there has been a sharp increase in the consumption of commodities with a short life-cycle. This is especially true for electronic equipment such as mobile phones, which are the focus of this paper. The short lifespan, which is due to continually substituting obsolete equipment with newer and more innovative models, has stimulated the growth in sales of these electronic goods. Europe continues to be the main mobile phone market in developed countries, but this growth has slowed down over the last two years. Despite being an already mature market, Italy has a “diffusion rate” (i.e., the number of active lines per 100 inhabitants) higher than 146, which is the highest in the European Union. This scenario demonstrated the need for a study examining the sustainability of the mobile phone sector according to two critical aspects that are often due to the behavioural patterns of the users: the first is the energy consumption of mobile phones and their associated equipment, and the second is related to the conflicting link between potential dematerialisation due to the miniaturisation of the devices and the resource consumption and waste generated in this sector. This paper discusses these two critical aspects and presents an overview of the Italian mobile phone sector, particularly related to the energy consumption during the use phase and increase of mass flows due to the devices circulating in Italy and the higher amount of the disposable products that have to be managed. The results show that, in Italy, the entire mobile phone system consumes approximately 2200 GWh per year, which is equal to 0.7% of the national electricity consumption, and produces potential e-waste from end-of-life devices totalling over 11 thousand tonnes for the period from 2007 to 2012. Concerning the issue of resources consumption, this estimate highlights that the potential savings in inputs, due to the reduction in device weight over time, has always been counteracted by their increasing demand.

In this paper, the most recent advances in the time-domain reflectometry (TDR)-based system for leak-localization in underground pipes are described in detail. More specifically, a new design of sensing element and the use of a new connection modality are proposed. Thanks to these new features, the practical implementation of the system becomes much quicker and its use more effective. Additionally, the present work also describes all the practical aspects and technical details (from installation to functional tests), related to the practical implementation of the system. Finally, to assess the possibility of further increasing the cost-effectiveness of the TDR-based leak localization system, experimental tests were carried out by comparatively using two TDR instruments, differing in specifications and costs, to identify the position of a leak.

In this work, the validation and the practical implementation of a methodology exploiting a time domain reflectometry (TDR)-system for monitoring rising damp in building structures are described in detail. The proposed system employs wire-like, passive, diffused sensing elements (SEs) that are embedded, at the time of construction or renovation, inside the walls of the building to be monitored. The SEs remain permanently inside the wall, ready to be interrogated when necessary. Experimental and simulation results are reported, which demonstrate the possibility of practical implementation and the associated performance in terms of sensitivity.

In this work, the performance of three time domain reflectometry (TDR) instruments (with different hardware architectures, specifications and costs) is comparatively assessed. The goal is to evaluate the performance of low-cost TDR instrumentation, in view of the development of a completely permanent TDR-based monitoring solution, wherein the costs of the instrument is so low, that it can be left on-site, even unguarded, and controlled remotely. Without losing generality, the applications considered for the comparative experiments are the TDR-based detection of leaks in underground pipes and, more in general, of soil water content variations. For this reason, both laboratory and in-the-field experiments are carried out by comparatively using three TDR instruments, in conjunction with wire-like sensing elements (SEs).

Olive oil production represents a big part of the Mediterranean economy, and as such it must be protected from frauds. For this reason, it is necessary to develop alternative low-cost techniques, applicable on large scale, for checking the quality of the product and for detecting adulteration. On such bases, the present work deals with the possibility of adopting microwave reflectometry for obtaining a 'spectral signature' of vegetable oils. For this purpose, time domain reflectometry (TDR) measurements, in combination with specific data processing, are first used for the dielectric characterization of several oil types. Successively, the acquired data are processed through the principal component analysis (for identifying clusters of oil types that exhibit common features) and through the partial least square analysis (for identifying a predictive model for detecting oil adulteration). Results confirm that the proposed procedure holds considerable potential for quality and anti-adulteration control purposes, especially in view of practical applications. © 2012 Elsevier Ltd. All rights reserved.

This paper explores the use of a microwave-reflectometry- based system for the automatic control and real-time monitoring of the flow and of the liquid level in intravenous (IV) medical infusions. In medical and hospital contexts, other kinds of devices, mainly based on the optical detection and counting of the infusion drops, are used. Nevertheless, the proposed system is aimed at circumventing some typical drawbacks deriving from the adoption of these traditional methods, thus allowing an efficient alternative for automatically monitoring the instantaneous flow of IV medical solutions. To this purpose, the proposed system combines microwave time-domain reflectometry (TDR) measurements with a noninvasive sensing element (i.e., strip electrodes directly attached to the external surface of the infusion bottle). Experimental results confirm that, by using low-cost portable TDR devices, the solution flow process can be controlled with acceptable accuracy. Therefore, the proposed method can be regarded as a promising control tool for in-hospital patient management as well as for telemedicine programs.

The paper discusses the problem of quantifying the contribution of systematic errors on the overall measurement uncertainty. After a brief review of the recommendations of the Guide to the Expression of Uncertainty in Measurement (GUM), and of some notable alternative methods already proposed in the literature, the authors outline a fully experimental approach, which is based on the ISO 5725 ideas, circumventing the adoption of the concepts of “degree of belief” and “subjective probability” which, instead, are central both in the GUM and in the proposed alternatives. As a matter of fact, the proposed experimental approach does not alter the mathematical framework of the GUM (differently from the alternative proposals), but imposes that the uncertainty is always an experimentally verifiable, or refutable, figure. Theoretical considerations are followed by the description of an experimental scheme to study the uncertainty due to systematic errors in generic instruments and, in particular, in ADC-based instruments. A major focus is given to experimental results obtained for the systematic gain error, which, in turn, plays a significant role in the overall error contribution. The ultimate goal of the paper is to provide a basis to promote reflections upon a central problem: how much subjectivity and objectivity should be allowed in an uncertainty evaluation.