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 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 this work, an innovative system for structural health monitoring of metallic pipes is presented. The proposed system relies on using the pipeline as a waveguide for the propagation of an electromagnetic (EM) signal: possible anomalies in the pipe provoke the partial reflection of the propagating EM signal. Differently from previous works that address similar applications, in this work, the EM test signal is injected in the pipeline/waveguide through a coaxial/waveguide transition that is made on the pipe surface (rather than on a cross-section as generally done). In practical applications, this strategy would allow to connect more easily the test equipment to the operating, buried pipes. Additionally, because reflections caused by anomalies may be difficult to identify with adequate accuracy, the authors have developed a dedicated processing strategy for the analysis of the reflections caused by anomalies. More specifically, by analyzing the measured reflected signal and by correlating it to the ideal reflected signal, it is possible to improve the localization of anomalies along the pipe. The proposed system, along with the processing and operating strategies were validated through full-wave simulations and experimental tests carried out on a steel pipe in presence of intentionally-provoked anomalies.

This work presents a microwave reflectometry-based system for monitoring large concrete structures (during the curing process and also while the structure is in use), through the combined use of punctual and diffused sensing elements. In particular, the adoption of punctual probes on a reference concrete specimen allows the development of an innovative and accurate calibration procedure, useful to obtain the value of the water content on a larger structure made of the same material. Additionally, a wire-like diffused sensing element can be permanently embedded in buildings and used to monitor the structure along the entire length of the sensing element. The adopted diffused sensing element can be used not only to detect dielectric variation during the curing process, but also throughout the service life of the structure. The combined use of punctual and diffused sensing elements represents an important innovation from a procedural point of view, able to provide detailed and quantitative information on the health status of the structure both during and after construction.

This article 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 medical infusions. In medical and hospital contexts other kind 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 optical sensing, thus allowing an efficient alternative solution for automatically monitoring the instantaneous flow of intravenous medical solutions. To this purpose, the proposed system combines microwave time domain reflectometry (TDR) measurements with a non-invasive 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 accurately controlled. Therefore the proposed method can be successfully adopted as a promising control tool for in-hospital patient management as well as for telemedicine programs.

Most sensing networks rely on punctual/local sensors; they thus lack the ability to spatially resolve the quantity to be monitored (e.g. a temperature or humidity profile) without relying on the deployment of numerous inline sensors. Currently, most quasi-distributed or distributed sensing technologies rely on the use of optical fibre systems. However, these are generally expensive, which limits their large-scale adoption. Recently, elongated sensing elements have been successfully used with time-domain reflectometry (TDR) to implement diffused monitoring solutions. The advantage of TDR is that it is a relatively low-cost technology, with adequate measurement accuracy and the potential to be customised to suit the specific needs of different application contexts in the 4.0 era. Based on these considerations, this paper addresses the design, implementation and experimental validation of a novel generation of elongated sensing element networks, which can be permanently installed in the systems that need to be monitored and used for obtaining the diffused profile of the quantity to be monitored. Three applications are considered as case studies: monitoring the irrigation process in agriculture, leak detection in underground pipes and the monitoring of building structures.