TDR moisture measurements in granular materials: From the siliceous sand test case to the applications for agro-food industrial monitoring

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.