Measurement approaches for the analysis of soil layer by microparticle adhesion

•Microsized soil particles adhere to the substrate forming a compact layer.•Weighing measurement is the basic method for estimating the deposited mass.•Image analysis is an effective method during on-field overhaul and inspections.•Optical and X-ray measurements give morphological and internal features. The soil layer is a common issue for energy systems as solar panels or prime mover and driven turbomachines. This phenomenon is usually known as fouling, and it consists of a microscopic layer (usually lower than 1 mm) that wraps the surface of these machines and devices. The presence of a deposited layer determines the modification of the surface characteristics as transparency or roughness with the consequent performance and efficiency reduction. In the present paper, a detailed investigation is carried out on seven measurement methods used for estimating the sand layer morphology and thickness. Each method has been applied for measuring similar soil layers, giving the possibility to compare the methodologies and show the capability of each method to obtain different information from the same specimen. Several guidelines and suggestions about technology, cost, and usefulness of each method are also included.