Investigation of electrical characteristics using various electrodes for evaluating the moisture content in wood

Hwang, Sung‐Wook; Hwang, Sung-Yun; Lee, Tae-Kyeong; Ahn, Kyung-Sun; Pang, Sung-Jun; Park, Jinseok; Oh, Jung-Kwon; Kwak, Hyo Won; Yeo, Hwanmyeong

doi:10.15376/biores.16.4.7040-7055

Cited by 8 publications

(4 citation statements)

References 34 publications

(50 reference statements)

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“…A regression model using two-pin resistance data accurately predicted MC. The four-pin probe consistently provided stable resistivity values, making it a reliable method for assessing moisture in large wood components [60]. Figure 7 shows the results of using the ERT on a fungi-infected oak with a heart rot in the darker part.…”

Section: Non-destructive Testingmentioning

confidence: 95%

Imaging of Structural Timber Based on In Situ Radar and Ultrasonic Wave Measurements: A Review of the State-of-the-Art

Pahnabi,

Schumacher,

Sinha

2024

Sensors

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With the rapidly growing interest in using structural timber, a need exists to inspect and assess these structures using non-destructive testing (NDT). This review article summarizes NDT methods for wood inspection. After an overview of the most important NDT methods currently used, a detailed review of Ground Penetrating Radar (GPR) and Ultrasonic Testing (UST) is presented. These two techniques can be applied in situ and produce useful visual representations for quantitative assessments and damage detection. With its commercial availability and portability, GPR can help rapidly identify critical features such as moisture, voids, and metal connectors in wood structures. UST, which effectively detects deep cracks, delaminations, and variations in ultrasonic wave velocity related to moisture content, complements GPR’s capabilities. The non-destructive nature of both techniques preserves the structural integrity of timber, enabling thorough assessments without compromising integrity and durability. Techniques such as the Synthetic Aperture Focusing Technique (SAFT) and Total Focusing Method (TFM) allow for reconstructing images that an inspector can readily interpret for quantitative assessment. The development of new sensors, instruments, and analysis techniques has continued to improve the application of GPR and UST on wood. However, due to the hon-homogeneous anisotropic properties of this complex material, challenges remain to quantify defects and characterize inclusions reliably and accurately. By integrating advanced imaging algorithms that consider the material’s complex properties, combining measurements with simulations, and employing machine learning techniques, the implementation and application of GPR and UST imaging and damage detection for wood structures can be further advanced.

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Section: Non-destructive Testingmentioning

confidence: 95%

Imaging of Structural Timber Based on In Situ Radar and Ultrasonic Wave Measurements: A Review of the State-of-the-Art

Pahnabi,

Schumacher,

Sinha

2024

Sensors

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“…Electrical resistance is the most common approach for moisture measurement in wood (Brischke et al 2008;Björngrim et al 2016;Hwang et al 2021a). Although the reliable range of moisture determination is limited, most portable commercial moisture meters for biomass are based on electrical resistance.…”

Section: Introductionmentioning

confidence: 99%

Investigation of NIR spectroscopy and electrical resistance-based approaches for moisture determination of logging residues and sweet sorghum

Hwang

Chung

Lee

et al. 2023

BioRes

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Techniques based on electrical resistance and near-infrared (NIR) spectroscopy were used to determine the moisture content (MC) of logging residues and sweet sorghum. The MC of biomass is a factor to be controlled that can affect the quality of final products. To accurately measure the moisture in fragmented materials, it is essential to increase the bulk density of the materials by compression. The low bulk density increased the error from the oven-drying MC and the variation between repeated measurements. The calculated correction factor made it possible to use a commercial wood moisture meter for biomass materials. Ordinary least squares regression models built with the electrical resistance data achieved coefficients of determination (R2) of 0.933 and 0.833 with root mean square errors (RMSE) of 0.505 and 0.891, respectively, for the MC predictions of logging residue and sweet sorghum. Partial least squares regression models combined with NIR spectroscopy achieved R2 of 0.942 and 0.958 with RMSE of 1.318 and 3.681 for logging residue and sweet sorghum, respectively. In contrast to the electrical resistance-based models, the NIR-based models could predict the MC regardless of the bulk density of the materials. Data transformation by the second derivative and removal of outliers contributed to the improvement of the prediction of the NIR-based models.

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“…A four-point probe method based on electrical resistivity has been proposed to compensate for the limitations of electrical resistance affected by the dimensions of a material (Hafsa et al, 2021;Hwang et al, 2021). Elec-trical resistance-and resistivity-based methods should account for the tree species, preservatives, stress conditions inside wood due to structural loads, and unstable electrode contacts.…”

Section: Introductionmentioning

confidence: 99%

Monitoring of Moisture and Dimensional Behaviors of Nail-Laminated Timber (NLT)-Concrete Slab Exposed to Outdoor Air

Hwang¹,

Chung²,

LEE³

et al. 2022

J. Korean Wood Sci. Technol.

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The moisture and dimensional behaviors of a nail-laminated timber (NLT)-concrete slab composed of an NLT-plywood composite and topping concrete are monitored for 385 days. The slab is developed for using as flexural elements such as floors. The humidity control of wood gently introduces significant fluctuations under the ambient relative humidity into the slab, and fluctuations in the relative humidity result in dimensional changes. The equilibrium moisture content of the slab increases from 6.7% to 15.3% during the monitoring period, resulting in a width (radial) strain of 0.58%. The length (longitudinal) strain is negligible, and the height (tangential) strain is excluded from the analysis because of abstruse signal patterns generated. Concrete pouring causes a permanent increase in the width of the NLT-plywood composite. However, the width deforms because the weight of the concrete mixture loosens the nail-laminated structure, not because of the significant amount of moisture in the mixture. The dimensional stabilization effect of the nail-laminated system is demonstrated as the composite strain is lower than the total strain of lumber and plywood, which are elements constituting the nail-laminated structure.

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Investigation of electrical characteristics using various electrodes for evaluating the moisture content in wood

Cited by 8 publications

References 34 publications

Imaging of Structural Timber Based on In Situ Radar and Ultrasonic Wave Measurements: A Review of the State-of-the-Art

Imaging of Structural Timber Based on In Situ Radar and Ultrasonic Wave Measurements: A Review of the State-of-the-Art

Investigation of NIR spectroscopy and electrical resistance-based approaches for moisture determination of logging residues and sweet sorghum

Monitoring of Moisture and Dimensional Behaviors of Nail-Laminated Timber (NLT)-Concrete Slab Exposed to Outdoor Air

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