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.

In this paper, different customized systems for microwave permittivity measurements on liquid samples, based on reflectometric measurements, are presented and analyzed. Their performance is compared against the one deriving from the most widely adopted commercial measurement setup. The systems are designed with the aim of providing less expensive solutions without compromising measurement accuracy. The purpose of the first proposed solution is to replace the commercial measurement software exploiting a reformulation of the classical theory. Based on this alternative formulation, a "homemade" probe is built by properly modifying an N-type coaxial connector, thus providing a system requiring a lower quantity of liquid under test. Moreover, a different experimental approach which uses time-domain reflectometry (TDR) instrumentation is presented. Such solution is by far the least expensive, as it allows avoiding the use of costly instrumentation (such as a vector network analyzer). In order to metrologically characterize the proposed solutions, a series of repeated measurements is performed on a set of well-referenced liquids. After extracting the Cole-Cole parameters through each of the considered measurement methods, the resulting type A uncertainty is evaluated. Finally, comparison with literature data allows the estimation of measurement bias. The analysis evidences that custom solutions generally exhibit an accuracy comparable to the one of the commercial solution, with a slight degradation of performance for the TDR-based setup, which, however, compensates for this drawback with its appealing low cost.

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 work, an accuracy analysis of the estimation of the time of flight (ToF) for time domain reflectometry (TDR) signals is carried out. For this purpose, three different criteria (referred to as ‘maximum derivative’, ‘zero derivative’, and ‘tangents crossing’) were comparatively applied for the evaluation of the ToF of a TDR signal propagating along a set of RG-58 coaxial cables (with different known length and with known electric parameters). Successively, as a further experimental test, the same criteria were applied on bi-wire cables with unknown electric parameters. Results show that, among the tested criteria, the ‘zero derivative’ criterion provided the best accuracy in the estimation of the ToF.

This book offers a comprehensive review of innovative measurement and monitoring solutions based on time domain reflectometry (TDR). This technique has numerous applications in several fields, ranging from the characterization of electronic devices to quality control of vegetable oils. However, most of the well-established TDR-based monitoring solutions rely on local or punctual probes; therefore, typically, to monitor large areas/volumes, a high number of probes must be employed, with the consequent maintenance and management requirements. On such bases, in the last few years, the authors have carried out extensive research on the use of diffused wirelike sensing elements to be used as probes for TDR measurements. The basic idea has been to extend the principles of punctual TDR-based monitoring to multi-purpose networks of diffused, sensing elements (SE’s), embedded permanently within the systems to be monitored (STBM’s). ese SEs can be tens of meters long, and can follow any desired path inside the STBM.; in fact, they are inactive inside the STBM. Additionally, these SE’s are passive (i.e., they do not require batteries) and their sensing ability is activated, by the TDR signal, when they are connected to the measurement instrument. In addition to this, these SE’s are completely maintenance-free. Starting from these considerations, this book addresses the use of low-cost, passive, flexible, wire-like SE’s to be used in conjunction with TDR. This book also provides several application test cases, with hints for practical implementation of the described monitoring systems

Time-domain reflectometry (TDR) techniques have become increasingly attractive for soil moisture evaluation thanks to their adaptability, low cost, and measurement accuracy. Many different TDR-based approaches are currently available for deriving moisture content: empirical calibration curve, empirical dielectric models, frequency-dependent dielectric mixing models, etc. Generally, TDR soil moisture measurements resort to multiple-rod probes, which provide good adhesion to the soil and ease of insertion. However, the typical configuration of such probes does not allow performing a short-open-load (SOL) calibration procedure, which is definitely necessary for retrieving accurate dielectric characterization from TDR waveforms. To overcome the impracticability of the traditional SOL calibration, in this paper, an innovative triple-short calibration (TSC) procedure for commercially available three-rod probes is proposed. First, the robustness of the TSC procedure is validated on well-referenced liquids, demonstrating that its application to TDR measurements leads to a substantial enhancement of the final accuracy in the evaluation of the frequency-dependent reflection coefficient. Successively, the TSC procedure is applied to TDR measurements performed on moistened sand samples. In particular, it is demonstrated that the proposed TSC method, applied to traditional TDR measurements in combination with a dielectric mixing model, leads to an accurate and effective moisture evaluation procedure. This goal is reached through an efficient optimization algorithm that minimizes the difference between experimental and theoretical reflection coefficients. Results show that the proposed strategy is a suitable candidate for low-cost, highly accurate, and easy-to-perform moisture content estimation of soils.

The paper deals with the problem of assessing the uncertainty due to systematic errors, especially in ADC or ADC-based instruments. The problem of defining and assessing systematic errors is briefly discussed, and the conceptual scheme of gage repeatability & reproducibility is adopted. Experiments are conducted in various conditions, and it is shown that modeling the variability of systematic errors is more problematic than the model suggested in the ISO 5725 norm. The solution to the problem of assessing the overall uncertainty is suggested through an in-depth analysis of all the separate causes of variations in measurements.

In this chapter, the basic concepts behind broadband microwave reflectometry (BMR) are recalled. First, a brief overview of the transmission line theory is provided, and the most common electromagnetic structures are introduced. Secondly, the major parameters that are used to characterize electrical networks are introduced, and the related theoretical background is briefly discussed. Finally, a short overview on dielectric spectroscopy is provided, thus anticipating its connection with reflectometric measurements.

Antenna characterization measurements are traditionally performed in the frequency domain (FD) through vector network analyzers (VNAs) in anechoic chambers. Nevertheless, the expensiveness of these facilities limits the possibility of using this approach for routine measurements. In this chapter, the strategies for the accurate evaluation of the reflection scattering parameter (S 11(f)) of antennas, starting from simple time domain reflectometry (TDR) measurements, are described. As a matter of fact, not only are instruments operating in time domain (TD) usually less expensive than VNAs; but they allow performing time windowing, which is the key for excluding the unwanted spurious reflection from the environment, thus avoiding the use of anechoic chamber.

Reflectometry is a powerful technique that can be effectively employed for a number of practical applications; in particular, the high versatility, the real-time response, and the potential for practical implementation have contributed to the success of microwave reflectometry for monitoring purposes. In this regard, this paper provides a survey of the current state of the art of reflectometry-based methods for diagnostics and monitoring applications. After a brief overview of the theoretical principles at the base of this technique, the different approaches of microwave reflectometry (time domain, frequency domain, and combined approaches) are fully discussed; particular attention is given to the strategies for enhancing measurement accuracy. Finally, the major practical applications of reflectometry and related results are discussed, thus evidencing current achievements, limitations, and potential.

This book is dedicated to the adoption of broadband microwave reflectometry (BMR)-based methods for diagnostics and monitoring applications. This electromagnetic technique has established as a powerful tool for monitoring purposes; in fact, it can balance several contrasting requirements, such as the versatility of the system, low implementation cost, real-time response, possibility of remote control, reliability, and adequate measurement accuracy. Starting from an extensive survey of the state of the art and from a clear and concise overview of the theoretical background, throughout the book, the different approaches of BMR are considered (i.e., time domain reflectometry - TDR, frequency domain reflectometry - FDR, and the TDR/FDR combined approach) and several applications are thoroughly investigated. The applications considered herein are very diverse from each other and cover different fields. In all the described procedures and methods, the ultimate goal is to endow them with a significant performance enhancement in terms of measurement accuracy, low cost, versatility, and practical implementation possibility, so as to unlock the strong potential of BMR.

In this chapter, the basic approaches of broadband microwave reflectometry are described in detail. More specifically, time domain reflectometry (TDR) and frequency domain reflectometry (FDR) are presented and the involved instrumentation is fully described. Successively, the FDR/TDR combined approach is described in detail: this approach can help exploit the benefits of both TDR and FDR, without necessarily employing two different measurement setups. Additionally, since the sensing element (or probe) plays a major role in all the aforementioned approaches, a comprehensive description of its design and of the corresponding performance is given. Finally, the basic principles leading to the possibilities of enhancing accuracy in BMR measurements are presented

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.

In this paper, a performance analysis, in terms of accuracy, linearity, and repeatability, of three criteria to estimate the time of flight in time-domain reflectometry (TDR) signals is carried out. In a first set of experiments, the three criteria [referred to as maximum derivative (MD), zero derivative, and tangent crossing (TC)] are applied to TDR signals propagating along a set of coaxial cables, with different known lengths and known electrical parameters. In a second set of experiments, the same criteria are applied to biwire cables in air, with different known lengths and unknown electrical parameters. Finally, in the last set of experiments, the criteria are applied in a more complex situation, i.e., on a biwire used as a sensing element for water-level measurement. The results show that, among the tested criteria, TC appears to provide a very good performance in terms of systematic errors and superior performance in terms of repeatability. The popular MD criterion appears to be more prone to random errors due to noise and TDR artifacts. The results of this paper are relevant to many practical applications of TDR, ranging from fault location in cables to media interface sensing.

In this paper, two customized systems for microwave permittivity measurements on liquid samples, based on reflectometric measurements, are presented and analyzed. Their performance is compared against the one deriving from the widely adopted commercial measurement setup, based on an open-ended coaxial line. The first custom system is built by properly modifying an N-type coaxial connector and relies on vector reflection coefficient measurements, while the second one uses a portion of liquid-filled coaxial line in conjunction with a time-domain reflectometry equipment. The systems are built for quality control and diagnostic purposes and their final aim is to extract the Cole & Cole dielectric model of the liquid under test. In order to metrologically characterize the systems, a series of repeated measurements is performed on a set of reference liquids. After the Cole & Cole parameters are extracted for each considered measurement method, the resulting type A uncertainty is evaluated. Comparison with literature reference data for the liquids also allows estimation of measurement bias. The analysis evidences that custom probes generally exhibit an acceptable measurement bias, but with a relevant loss of accuracy in the estimation of some Cole & Cole parameters for lossy liquids. Possible improvements are under investigation for enhancing their performance and make them appealing substitutes for the commercial setup.

In this work, a dielectric permittivity measurement system, to be used for quality control of edible oils, is presented. The proposed system relies both on low-frequency and high-frequency measurements (performed through and LCR meter and through a time-domain reflectometer, respectively), thus allowing a “broadband” investigation of the dielectric behavior of edible oils. The adoption of a single, specifically-designed probe (used for all the measurements), along with the possibility of using portable instrumentation, makes the proposed system an appealing candidate for the realization of a continuous, on-site system for quality monitoring of edible oils. The proposed system was first validated on materials with well-known dielectric characteristics. Successively, it was used to investigate the dielectric behavior of some autochthonous varieties of olive oils and of seed oils. The ultimate goal of this work is to pave the way for the development of an alternative method of analysis that could be able to distinguish among different kinds of oils, to certify oil quality and origin, and to detect the possible presence of adulterants.

The design and preliminary metrological characterization of a waveguide system for complex permittivity measurement on both compact and granular materials is presented. The proposed system is intended for the dielectric characterization of asphalt concrete and of its components at frequencies around 2.45 GHz. Therefore, the system easily allows performing measurements on granular materials, such as mineral aggregates found in the asphalt concrete. A series of experimental tests on reference materials shows, via comparison with a standard measurement system, errors within 1%. A theoretical analysis of uncertainty contributions confirms a predicted expanded uncertainty lower than 5%.

In this work, the design, the realization and the experimental characterization of a parallel-plate admittance cell with no guard ring, to be used for low-frequency dielectric permittivity measurements of liquids, are presented. In contrast to guarded-terminal cells, the proposed admittance cell can be easily connected to any LCR meter (even a two-terminal one) employing traditional test fixtures for axial/radial devices. Additionally, the fringing effect is compensated for through a correction factor ($alpha$), obtained from electromagnetic simulations of the structure, rather than through time-consuming experiments on a number of reference liquids or adopting approximated theoretical formulations. Finally, to verify the suitability of the fabricated admittance cell for low-frequency dielectric spectroscopy and to assess its metrological performance, a set of measurements was carried out on six reference non-ionic liquid materials. The results show that the accuracy is comparable with the typical measurement accuracy achievable, at much higher costs, when using commercial solutions.

This paper deals with the shape of the GPR diffraction curve in dependence of the distance of the measurement line from to the air/soil interface. It will be shown that the diffraction curve changes with respect to the case of data gathered at the air-soil interface, and the calculation of the diffraction curve requires the solution of a fourth degree algebraic equation. The solution in closed form of this equation will be presented, and a physical discussion of the effects of the non-null height of the observation line will be provided

The present work describes two practical application scenarios for an innovative, diffused, low-cost sensing system, which can be permanently embedded in the system to be monitored (STBM), thus allowing the continuous, real-time monitoring over its whole life cycle. The basic idea of the considered sensing system is to endow the STBM with flexible, wirelike sensing elements (SE’s), to be used in conjunction with time domain reflectometry (TDR). One of the crucial advantages of the proposed sensing system is that a SE could be tens of meters long; hence, one single SE may suffice to monitor large areas in a single shot. The two practical applications considered in this paper relate to moisture monitoring of building structures and to the management of irrigation in agriculture: for each of these application fields, preliminary experimental tests were performed, and the potential and limitations of the considered sensing system were assessed. Finally, in order to evaluate the metrological performance of the sensing systems, an additional set of experiments was carried out employing six different types of wire-like SE’s and the obtained results were comparatively assessed.

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

Monitoring soil moisture is a major interest for several practical applications. This task can be suitably performed through various methods; however, at the state of the art, there is not a single method that successfully combines ease of use, low cost, customization, possibility of measuring large volumes, and, most importantly, measurement accuracy. In this regard, seismic wave propagation (SWP)-based methods, which rely on the evaluation of the propagation velocity of a seismic wave vc through the soil sample under investigation, hold considerable potential for practical implementation. On such bases, in this work, first the authors propose an enhanced version of a previously developed SWP-based system for soil moisture measurement. Successively, to provide an exhaustive performance characterization of the system, a specific comparative methodology, based on reference time-domain reflectometry (TDR)-based measurements, is addressed. More specifically, SWP- and TDR-based measurements are simultaneously performed on river sand for increasing levels of water content. The TDR-measured moisture levels are taken as reference values and are used to infer the theoretical propagation velocity values vc, REF. Then, these reference values are suitably compared with those directly measured through the SWP-based system (vc, MEAS), thus allowing a consistent metrological assessment. The ultimate goal of this work is to validate and characterize the performance of the proposed SWP-based system in view of practical implementation for soil moisture evaluation.

In this paper, a time-domain reflectometry (TDR) based system for monitoring liquid level inside tanks is presented. The proposed system resorts to a flexible, two-wire probe, which can be attached to the walls of containers and adapted to their shape. The proposed system is particularly useful for industrial applications; in fact, after a preliminary calibration, it can measure automatically and in real time the level of liquids inside containers (even tens of meters tall). The proposed system was tested on metallic and on nonmetallic containers. In the latter case, as the probe is positioned on the outside wall of the container, a totally noninvasive monitoring of liquids is achieved. The obtained results show that the system has considerable potential for being easily and effectively employed in practical, industrial applications. Finally, simulations were carried out, thus providing useful information for optimizing the system performance and for predicting its limitations.

In this work, an innovative cellulose-based superabsorbent polymer (SAP) was experimentally assessed as an environmentally friendly alternative to acrylate-based SAPs, for the optimization of water consumption in agriculture. The cellulose-based SAP was synthesized and tested for its swelling capability in different aqueous media. The effectiveness of the SAP in agricultural applications was then evaluated by analyzing its performance after several absorption/desorption cycles, over a period of approximately 80 days, upon addition to different types of soil, i.e., white and red soil, for the cultivation of two varieties of plants typical of the Mediterranean area (tomatoes and chicory). The results confirmed that SAP-amended soil can store a considerable amount of water and can release it gradually to the plant roots when needed. The adoption of the proposed SAP in cultivations could thus represent a promising solution for the rationalization of water resources, especially in desert areas.

In the present work, an alternative probe configuration to be used for time domain reflectometry (TDR)-based monitoring of liquid level inside tanks is presented. The proposed probe, which resorts to a bifilar transmission line configuration, is flexible and adaptable to the surface of the containers to be monitored. This feature, along with the other advantageous characteristics of TDR, makes this probe configuration particularly attractive for industrial applications. In this paper, to test the applicability of the method, two different scenarios are considered: monitoring of liquids contained in metallic tanks and non-invasive monitoring of liquids in non-metallic tanks. Results show that, in both cases, the proposed system has considerable potential for being easily and effectively employed in practical, industrial applications.

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.

In this paper, a time-domain reflectrometry (TDR)- based solution for monitoring moisture content in cement-based samples is presented. The proposed system employs a simple flexible biwire, which acts as a distributed sensing element (SE) (as opposed to traditional, local moisture content sensors). Once embedded, the SE remains permanently inside the cement-based sample and can be used both for monitoring the hydration process of the sample structures (ex-ante monitoring) and, successively, for monitoring possible water infiltration during the service life of the structure (ex-post monitoring). In practical applications, the SE could be employed inside building structures at the time of construction, and it could be used for the aforementioned moisture content monitoring purposes. As a preliminary validation of the practical feasibility of the proposed system, in this paper, two cement-based samples (made of mortar and concrete, respectively) were equipped with a SE, and their water content was monitored through TDR measurements, over a 28-day period (thus mimicking the ex-ante monitoring conditions). Furthermore, to verify the potential of the proposed method also for the ex-post monitoring, the air-dried mortar sample was intentionally subjected to wetting conditions and the resulting rising damp was observed through the proposed TDR-based system.

Accurate measurement of the static electrical conductivity provides a great insight into the characteristics and quality status of various materials. To overcome some limitations of the traditional measurement methods, there has been a growing interest toward the investigation of enhanced techniques for measuring electrical conductivity. In this regard, time-domain reflectometry (TDR) has attracted considerable attention, also due to the possibility of simultaneously monitoring different physical parameters. Although initially introduced for monitoring soil properties, the application of the TDR-based technique might be an interesting and cost-effective means in many other fields. However, the accuracy of traditional TDR-based electrical conductivity measurements is strongly influenced by the preliminary calibration technique. On such basis, in this paper, two innovative approaches for a more straightforward and accurate evaluation of the electrical conductivity are presented. The first method relies on the combination of the TDR measurement with transmission-line modeling (TLM); the second method simply relies on a couple of independent capacitance measurements (ICMs) performed through an LCR meter. As a further goal, the metrological performance of this last method is compared with that of the traditional method, thus validating its applicability. Experimental results and related uncertainty analysis on various samples demonstrate that the proposed alternative method is definitely suitable for a simpler and accurate estimation of the static electrical conductivity, also when dealing with moistened soils.

In this work, a novel technological solution for the traceability of hides throughout the leather manufacturing process is addressed. The proposed solution relies on marking the raw hide with a permanent sub-surface tattoo, made with specific substances used as identification markers. In practical applications, the markers can be embedded so as to form a pre-established pattern, thus creating a unique identification code. To experimentally demonstrate the feasibility of the proposed solution, in this work, different types of markers were injected in a raw hide (i.e., prior to its tanning). After the tanning process, the persistence of the markers and of their pattern was verified by comparatively inspecting the hide with two different sensing technologies: microwave reflectometry and X-ray imaging. The obtained results demonstrated that the proposed traceability system is a promising solution to circumvent the age-old problem related to counterfeiting and fraudulent substitutions of raw materials in the leather manufacturing industry.

In this paper we propose an experimental case of the joint use of ground penetrating radar (GPR) and time domain reflectometry (TDR) for the estimation of the dielectric permittivity of soil. In particular, the well known method of the diffraction curves is compared with the results of an “autofocussing” strategy based on a linear microwave tomographic approach and with a TDR measurement. The effect of the actual offset between the antennas is accounted for too.

In this paper, the practical implementation of an innovative time domain reflectometry (TDR)-based system for leak detection in underground water pipes is presented. This system, which had been previously developed and experimented on pilot plants, has now been installed (for the first time) on a large scale, in 10 km of pipes. The present work describes all the practical aspects and technical details (from the design to the functional tests), related to the implementation of the system.

The design and the experimental characterization of a waveguide system for complex permittivity measurements on both solid and granular materials are presented. The proposed system is intended for the dielectric characterization of asphalt concrete and of its components at frequencies around 2.45 GHz. Therefore, the system provides measurements on granular materials, such as mineral aggregates found in the asphalt concrete. A series of experimental tests on reference materials shows, via comparison with a standard measurement system, errors within 1%. A theoretical analysis of uncertainty contributions confirms a predicted expanded uncertainty lower than 2%. Furthermore, to test the proposed system for dielectric spectroscopy on materials typical of the asphalt industry, measurements were also performed on calcareous and basaltic materials, which are typically used for the production of asphalt. Finally, three different dielectric models (namely, α model, Ansoult’s model, and Topp’s equation) were comparatively assessed to identify the most suitable ones in describing the water content and dielectric permittivity relationship for the considered materials.

Il presente lavoro riguarda lo studio di fattibilità e una validazione preliminare di un sistema capacitivo per la misura delle variazioni del contenuto d’acqua del terreno, impiegando elementi sensibili (ES), con una configurazione bifilare, flessibili e “diffusi”. In letteratura, sono presenti sensori capacitivi in cui l’umidità viene misurata partendo da misure della capacità tra elettrodi inseriti nel terreno. Anche in questo caso, si tratta comunque di sensori puntuali con un limitato volume di sensing. Viceversa, nel sistema di misura proposto, ciascun ES può essere lungo decine di metri e, grazie alla sua flessibilità, può seguire qualunque percorso lungo la coltivazione.

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.

In this work, the dielectric characterization of pietra gentile (a kind of stone typically found in Cul-tural Heritage structures in Southern Italy) was carried out. Measurements were performed for increasing level of water content of the pietra; thus identifying, empiri-cally, the relation between moisture content and dielec-tric permittivity. The obtained laboratory results can be used to derive moisture content/dielectric permittiv-ity calibration curves that could be used, in practice, for noninvasive on-the-field moisture monitoring of pietra gentile-made Cultural Heritage structures. For exam-ple, it would be possible to use the obtained calibration curves with non-invasive measurement systems, such as time domain reflectometry in conjunction with anten-nas, coaxial probes, or waveguides apertures.

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).

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.

This chapter focuses on broadband microwave reflectometry (BMR) applications for monitoring water content (θ) and static electrical conductivity (σ 0) of granular materials, with particular emphasis on applications for soil measurements. First, a TDR-based method for inferring θ from measurements of the apparent dielectric permittivity is presented. This approach, which relies on the individuation of so-called calibration curves, is discussed in detail and the related metrological assessment is provided. Successively, a more accurate method that takes into account the frequency-dependence of the dielectric permittivity of the moistened granular material (considering the permittivity of each single constituent) is presented. This application is also used as test-case for validating an innovative calibration procedure that is particualrly useful when the traditional short-open-load (SOL) calibration cannot be performed. Furthermore, the adoption of antennas in place of the traditional probes is discussed (thus assessing the possibility of guaranteeing a noninvasive approach). Finally, two innovative strategies for enhancing and simplifying TDR-based measurements of static electrical conductivity σ 0 (typically used in soil science) are presented.

Quality control of vegetableoils is becoming more stringent, and strict laws are being enforced, especially for avoiding adulteration. The public bodies that are responsible for the prevention of the adulteration of foodstuffs necessitate methods of analysis that could facilitate large-scale in situ controls. Similarly, oil producers constantly strive to speed up internal qualitycontrol. As a direct consequence, there is an increasing demand for innovative methods of analysis that could guarantee real-time in situ monitoring and provide adequate accuracy. On such bases, the present work addresses the possibility of monitoring qualitative characteristics of vegetableoils through microwavedielectricspectroscopy. To this purpose, the Cole–Cole dielectric parameters of different vegetableoils are evaluated through an innovative automatable procedure that suitably combines traditional TDR measurements, SOL calibration, frequency domain processing, TL modelling and, finally, a minimization routine. The proposed procedure is carried out first on different “pure” oils and, secondly, on some oil mixtures. The obtained results confirm that different dielectric characteristics are associated with different oils, thus confirming the considerable potential of dielectricspectroscopy for quality and anti-adulterationcontrol purposes, especially in view of practical applications.

In this chapter, broadband microwave reflectometry (BMR)-based methods for measuring simultaneously the levels and the dielectric characteristics of liquid materials are presented. First, an approach based solely on time domain reflectometry (TDR) measurements and on the analysis of TDR waveforms is described. Secondly, a further enhancement of this method is accomplished by resorting to the combination of TDR with frequency domain reflectometry (FDR). Also this method provides, in one shot, the level and the dielectric permittivity of the considered liquids (this time, the complete spectral signature is obtained in terms of Cole-Cole parameters). This approach is considered the optimal solution especially when dealing with dispersive media. In this second measurement method, the accuracy is enhanced also through the adoption of a transmission line (TL) modeling of the measurement cell and through the realization of a custom-made fixture that allows performing short-open-load (SOL) calibration measurements. Finally, BMR-based measurements of the dielectric characteristics are extended to edible liquids: in particular, vegetable oils are considered. Reported results show that all the proposed methods have strong potential for possible practical implementation in the field of industrial monitoring. It will be evident how, in all the considered approaches, the design of the probe is crucial for enhancing the final measurement accuracy

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 feasibility of the adoption of microwave reflectometry (MWR) for diagnosing the status of structures made of composite materials is investigated. In particular, two different “sensing structures”, based on microstrip and coplanar configurations, are considered. The analysis focused on carbon fibre-reinforced composite structures, which are extensively used in aircraft industry. It goes without saying that, despite the widespread diffusion of this class of materials in the aircraft industry, there are two crucial requirements for which effective diagnostic methods are far from being adequately implemented. First, it is necessary to detect the possible presence of gaps between structural components after they are assembled. Secondly, there is the need to periodically control (during the service life of the aircraft) the amount of moisture that may have been absorbed by the composite structure. To this purpose, the present work intends to pave the way for future practical implementation of MWR based systems for these diagnostic requirements.

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.

La gestione dei sistemi di distribuzione idrica dovrebbe sempre prevedere un planning accurato delle operazioni diagnostiche e di riparazione. Un simulatore, pertanto, può essere un utile strumento per la previsione dei guasti e per la pianificazione delle operazioni di riparazione. Poiché la simulazione delle reti di distribuzione idrica presenta un gran numero di gradi di libertà, la miglior soluzione per l’ottenimento di un sistema estremamente semplificato e allo stesso tempo personalizzabile sembra essere l’uso di un semplice modello probabilistico, un tipo di approccio usato per esempio in relazione a pipeline sottomarine di petrolio e gas.

Different approaches are commonly available for the continuous monitoring of moisture and dielectric properties of various materials. In particular Time Domain Reflectometry (TDR) is the standard method for measuring soil water content. Nevertheless, the state of the art is rather lacking in assessing specific calibration procedures allowing the accurate moisture monitoring of granular materials. To fill this gap, the adoption of TDR for such purposes is investigated. Starting from measurements on siliceous sand, an in-depth analysis is extended to various feedstuff materials (such as corn, corn flour and bran). Furthermore, the adopted methodology is fully assessed from a metrological point of view, thus confirming its suitability for the considered applications.

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, three different techniques, namely time domain reflectometry (TDR), ground penetrating radar (GPR) and electrical resistivity tomography (ERT) were experimentally tested for water leak detection in underground pipes. Each technique was employed in three experimental conditions (one laboratory or two field experiments), thus covering a limited but significant set of possible practical scenarios. Results show that each of these techniques may represent a useful alternative/addition to the others. Starting from considerations on the obtained experimental results, a thorough analysis on the advantages and drawbacks of the possible adoption of these techniques for leak detection in underground pipes is provided.

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

This work aims at assessing the practical applicability of an innovative time domain reflectometry (TDR)-based system for leak localization in underground pipes. For this purpose, two laboratory experiments were carried out. The first experiment (E1) allowed assessing the reliability of the TDR system in presence of two simultaneous leakage-like conditions. The second experiment (E2), which was also carried out in presence of two leaks, allowed assessing the possible effect of the type of soil on the performance of the leak-detection system. Results show that, differently from traditional leak detection methods, the TDR-based system can correctly localize the presence of two simultaneous, closely-spaced leaks and that the type of soil has very little influence on the performance of the system. Finally, in this work, the practical implementation of the system in urban areas is also addressed, thus highlighting the steps to maximize the effectiveness of the system

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

This paper deals with the assessment of the uncertainty due to systematic errors, particularly in A/D conversion-based instruments. The problem of defining and assessing systematic errors is briefly discussed, and the conceptual scheme of gauge repeatability and reproducibility is adopted. A practical example regarding the evaluation of the uncertainty caused by the systematic offset error is presented. The experimental results, obtained under various ambient conditions, show that modelling the variability of systematic errors is more problematic than suggested by the ISO 5725 norm. Additionally, the paper demonstrates the substantial difference between the type B uncertainty evaluation, obtained via the maximum entropy principle applied to manufacturer’s specifications, and the type A (experimental) uncertainty evaluation, which reflects actually observable reality. Although it is reasonable to assume a uniform distribution of the offset error, experiments demonstrate that the distribution is not centred and that a correction must be applied. In such a context, this work motivates a more pragmatic and experimental approach to uncertainty, with respect to the directions of supplement 1 of GUM.

In this paper a time domain reflectometry (TDR)-based solution for detecting water leaks in underground pipes is described and experimentally validated. The proposed method strongly reduces the inspection time that is typically required by traditional leak detection methods. In fact, it can successfully inspect even hundreds-of-meters long pipes. In this work, two different configurations of the system are described: one can be used for detecting leaks in ‘already-installed’ metal pipes; whereas, the other is suitable to be employed for detecting leaks in ‘newly-installed’ pipes made of any material. The performance of both these system configurations was assessed through an extensive, on-the-field experimental campaign, carried out with the collaboration of one of the largest European water operators, Acquedotto Pugliese S.p.A. (AQP). Three experimental cases (ECs) representative results related to both configurations are reported and commented on. Finally, some practical consideration for the applicability of the system are also provided.

In this paper, the experimental validation of a time domain reflectometry (TDR)-based method for pinpointing water leaks in underground metal pipes is presented. The method relies on sensing the local change in the dielectric characteristics of the medium surrounding the leak point. The experimental validation of the method was carried out through measurements performed on a pilot plant (experimental case P1) and through on-the-field measurements performed on two 'already-installed pipes', i.e., already operating and connected to the water distribution system (experimental cases P2 and P3). For the pilot plant, different leak conditions were imposed and the corresponding TDR responses were acquired and analyzed. For the on-the-field measurements, TDR measurements were performed on pipes for which a leak-detection crew had preliminarily individuated the possible presence of leaks (through traditional leak-detection methods). Finally, in view of the practical implementation of the proposed TDR-based leak-detection system, a data-processing procedure (which gives an automatic evaluation of the position of the leak) is also presented.

In most water distribution systems, a fairly sizable amount of water is lost because of leaks and faults in pipes. For this reason, the individuation of leaks is extremely important for the optimization and rationalization of water resources. However, the techniques and methodologies that are currently used for the individuation of leaks, despite being universally accepted, are extremely time-consuming and require highly-experienced personnel. Additionally, such techniques become unreliable and ineffective when the measurements are not performed in specific operating conditions of the pipe (e.g., high water pressure). On this basis, in this paper, a time domain reflectometry (TDR)-based system for the non-invasive detection of leaks in underground metal pipes is presented. Not only does the adoption of the developed system leads to accurately pinpoint the leak, but it also allows to dramatically reduce the required inspection times. The TDR-based system for leak detection is described in detail (with particular attention to the measurement principle behind the method and to the methodology). Furthermore, a strategy for enhancing the accuracy in pinpointing the leak is addressed. The proposed system is validated through experimental campaign that consisted in carrying out a leak-detection survey through the traditional methods and through the proposed method.

In this paper, a time domain reflectometry-based system for locating leaks in underground pipes (made of any material) is presented. The proposed system simply requires that a biwire should be attached to the pipe (all along its length), at the time of installation. Basically, the biwire acts as a permanent sensing element that can be connected to the measurement instrument whenever it is necessary to check for the presence of leaks. It is worth emphasizing that such a simple and low-cost system could tremendously facilitate leak detection not only in water distribution systems but also in wastewater/sewer pipelines. The proposed system was validated through measurements on a newly installed pilot plant, in which a leak was intentionally provoked.

In this paper, a time domain reflectometry (TOR)based system for the non-invasive localization of leaks in underground pipes is described and experimentally validated. The proposed system simply relies on TOR measurements performed on a two-wire cable (biwire) that is rolled out on the underground pipe at the time of installation of the pipe (but made accessible from the road surface through an inspection well); the biwire on the pipe acts as a permanent, distributed sensing element and can be connected to the TOR instrument whenever it is necessary to perform a check. Two of the major advantages of the proposed system are that it can be employed with pipes made of any material and that it strongly reduces the inspection time typically required by traditional leak detection methods. To validate the system and to assess its performance, a new pipe was installed and a leak condition was intentionally provoked at a reference position. The TOR system was then used to evaluate the position of the leak as if had been unknown. The results of this experimental test are reported and thoroughly discussed.

Water-leak detection is extremely important for the optimization and rationalization of water resources. However, the techniques that are currently used for individuating leaks are extremely time-consuming; also, they require highly-experienced personnel and often become unreliable when measurements are not performed in specific operating conditions of the pipe (e.g., high water pressure). On such bases, in this paper, a time domain reflectometry (TDR)-based system for the non-invasive detection of leaks in underground metal pipes is presented. This system was validated through specific experimental tests, performed on a length of pipe where leaks were intentionally created. Experimental results demonstrate not only that the proposed system can successfully individuate the position of the leak (still reducing the inspection time with respect to traditional methods), but most importantly, they demonstrate that the system fares well even when multiple leaks are present. In this paper, after a brief description of the theoretical principles behind the proposed system, the experimental validation of the system is thoroughly described and commented on.

This paper describes an innovative system for accurate, non-invasive detection of water leaks in underground pipes. The proposed system, based on microwave reflectometry, allows to effectively detect leaks with a dramatic reduction of inspection times. For the method and the related measurement apparatus, an international patent application has been filed.

Recently, an innovative system based on time domain reflectometry (TDR) for the individuation of leaks in underground pipes has been proposed and validated. Starting from the results obtained so far, the present works aims at further investigating the practical applicability of the aforementioned system. In particular, the goal of this work is to assess the system in the detection of two close leaks (i.e. leakages that may occur on the same length of pipe). To this purpose, an experimental setup was arranged: two "leakage conditions" were imposed, and the position of the leaks were considered as unknown and calculated through the dedicated developed algorithm. Results show that, differently from traditional leak detection methods (in which the presence of a leak may "mask" the presence of other leaks), the TDR-based system successfully individuates and correctly localizes the presence of two leaks.

The present invention pertains to a methodology for the identification and traceability of materials in industrial process, with particular focus on the traceability of leather and leather-like materials throughout the manufacturing process of leather or leather-like products. Said methodology comprises, at least, the employment of the following: identification markers (3); a method for permanently embedding the markers inside the item (2) to be traced; a device for generating an electromagnetic signal to be used as stimulus for the marked material; a device for acquiring the response of the marked material to the applied stimulus; and a device for recording the aforementioned response.