Comprehensive Evaluation of Soil Moisture Sensing Technology Applications Based on Analytic Hierarchy Process and Delphi

The demand for smart irrigation and water-saving practices in agriculture has triggered the development of different soil moisture sensing techniques that can operate under harsh field conditions. In this study, a soil moisture sensing technology appropriate for the field applications was comprehensively evaluated. From a qualitative and quantitative perspective, the Delphi and analytic hierarchy process methods were used to construct an index system involving technological advantage, economic benefit, risk analysis, policy support, four second-level indicators, and 23 fourth-level indicators. The results showed that economic benefits account for the largest weight. The practical evaluation resulted in 12 farms that showed that the selected soil water sensing methods performed reasonably and exhibited obvious water-saving irrigation benefits, which are usually used for scheduling irrigation. The overall score of M4 in different soil types was 0.2% lower than that of M5. Farms with reasonable economic conditions and a high awareness scored 5.3% higher on technology than those with modest economic conditions, which clearly affects the evaluation scores of the two technologies. The evaluation results help farmers and government decision-making bodies in technology selection, production decision-making, and risk control.

Zn2+-Doped TiO2:WO3 Films Prepared by Electrospinning and Sintering: Microstructural Characterization and Electrical Signature to Moisture Sensing

In this work, Zn2+-doped TiO2:WO3 nanostructured films, with different doping levels, were produced by electrospinning followed by sintering, and tested as potential materials for relative humidity (RH) detection. The materials microstructure was investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, and X-ray diffraction (XRD). The electrical characterization was performed by electrical impedance spectroscopy in the range of 400 HZ–40 MHZ, at 20 °C. The sensors’ sensitivity to moisture was evaluated from the impedance variations in response to changes in RH (10–100%). The analyses confirmed the interaction of water molecules with the oxides surface, and showed that zinc atoms were incorporated into the titanium vacancies in the crystal lattice. All the studied sensors showed a p- to n-type conduction transition taking place at around 40% RH. The nanocomposite with 2 wt% of dopant presented the best sensitivity to moisture, with an impedance variation of about 1 order of magnitude. The results are discussed in relation to the microstructure and fabrication route.

Embroidered Textile Antennas: Influence of Moisture in Communication and Sensor Applications

Moisture causes detuning and increased losses in textile antennas, and it affects resonant and wideband textile antennas differently. In this work, we studied the effect of moisture on a resonant textile planar inverted-F antenna (PIFA) and a wideband textile monopole antenna. Both antennas were manufactured by embroidering conductive yarn in denim textile. The input reflection coefficient, antenna gain, and gain patterns were measured on both antennas for different moisture contents. The results show that wideband antennas are less affected by moisture in comparison with resonant antennas. For communications applications, large moisture content in the textile antenna should be avoided; therefore a flexible, textile-based waterproofing antenna cover was proposed, manufactured, and tested. On the other hand, the effect of antenna detuning by moisture can be used for moisture-sensing application. This concept was demonstrated on the resonant textile PIFA in transmission and reflection setups, showing that the reflection setup gives better results.