An electrical method for estimating the moisture content of Moluccan Albizia wood

Abstract

Wood moisture determination is essential for enhancing drying process, reducing the transport expenses and achieving environmental sustainability by avoiding the unnecessary wood decaying due to fungus. The direct determination of moisture content of wood is based on the oven drying technique which is a time consuming and expensive work. Hence, the real-time determination of wood moisture is crucial, especially in wood industries. Wood is a naturally occurring composite material with complex heterogeneous structures. The dielectric qualities of wood change with the moisture content include inside the material depending on the environment temperature and relative humidity. In this study, dielectric property, capacitance was used as the core factor to determine the moisture content of identical wood samples of Albizia falcataria, commonly known as the Moluccan albizia having dimensions of 20 cm × 20 cm using a parallel plate capacitor. Four identical wood samples were subjected to forceful absorption of water and kept inside a microwave oven for different time durations to measure the initial masses and calculate the corresponding moisture content percentages. The capacitances of wood samples were measured for different moisture levels at room temperature using a LCR meter which applied a constant and optimum frequency of 10 kHz. The cubic regression model was chosen as the best fit model, since it showed 98.46% and 98.43% for adjusted 𝑅2 and 𝑅2 values respectively. The root mean square error of the regression model was found to be 1.8, and randomly selected four wood samples of the same species were tested for their moisture contents using the proposed method, and the results were compared with the moisture content percentages calculated using the standard method. The proposed parallel-plate capacitor method demonstrated 97.7% accuracy with respect to the standard method. Hence, extended implementation of this cost-effective, time-saving method can be used in the industrial field to take the real-time moisture content measurements below 50% with high accuracy.