Dielectric and ultrasonic properties of rubber wood. Effect of moisture content grain direction and frequency

Kabir, Mohammed F.; Daud, W. M.; Khalid, Kaida; Sidek, H.A.A.

doi:10.1007/s001070050305

Cited by 25 publications

(18 citation statements)

References 12 publications

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“…These results are most likely due to the impact of water on the dielectric properties. Kabir et al (1998) reported that the dielectric properties of rubber wood increased with moisture content up to 30% in both grain directions at low and microwave frequencies. Sahin and Ay (2004) reported that the dielectric properties of three hardwood Euramerican hybrids (poplar, alder, and oriental beech) at 9.8 GHz increased with moisture content in the range of 0 to 28%.…”

Section: Resultsmentioning

confidence: 99%

Measurements of Thermal and Dielectric Properties of Medium Density Fiberboard with Different Moisture Contents

Zhou¹,

Hu²,

Hu³

2013

BioResources

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The thermal and dielectric properties of medium density fiberboard (MDF) with different moisture contents were measured by light flash and the parallel-plane capacitor method, respectively. The results show that increasing moisture content has a positive effect on both thermal properties and dielectric properties. The higher the moisture content, the higher the thermal conductivity and dielectric properties were. The thermal conductivity of MDF with different moisture contents varies in the temperature range of 25 to 150 ºC in a double-hump pattern rather than a proportional pattern. The dielectric constant decreases with increasing frequency up to 1000 MHz. The dielectric loss factor undulates within the frequency range of 1 to 100 MHz, and the peak value occurs at around 10 MHz. The results presented in this study can be used for radio frequency heating, wood building energy, material design, and radio frequency evaluation.

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Section: Resultsmentioning

confidence: 99%

Measurements of Thermal and Dielectric Properties of Medium Density Fiberboard with Different Moisture Contents

Zhou¹,

Hu²,

Hu³

2013

BioResources

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“…When the moisture content is lower than the fiber saturation point, the stress wave velocity rapidly decreases with the moisture content. When the moisture content is higher than the fiber saturation point, the stress wave velocity gradually decreases with moisture content (Kabir et al 1998;Kang and Booker 2002;Oliveira et al 2005). Further, a constant increase in the stress wave velocity with the decreasing moisture content from initial to oven-dry was also observed by Simpson and Wang (2001).…”

Section: Introductionmentioning

confidence: 63%

Effects of Moisture Content and Fiber Proportion on Stress Wave Velocity in Cathay Poplar (Populus cathayana) Wood

Liu¹,

Gao²,

Chen³

et al. 2014

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Changes in longitudinal stress wave velocity measured during the drying process of Cathay poplar (Populus cathayana) wood at different moisture contents were investigated. The test was performed at five different positions from bark to pith on each part. Five bars, cut successively from bark to pith with different fiber proportions, were also tested. The corrected velocity was calculated by dividing the velocity by the fiber proportion to negate any possible effects of wood structure on the velocity. The results showed that the longitudinal stress wave velocity decreased with increasing moisture content. Such trends were more obvious when the moisture content was lower than the fiber saturation point (FSP). The longitudinal stress wave velocity increased with increasing fiber proportion. A linear relationship between the corrected velocity and the moisture content was observed. This linear relationship was similar to the relationship between the relative velocity and the moisture content.

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“…Time domain reflectometry (TDR) is also a common method (Nadler et al, 2003); however, it damages tree surfaces because a hole needs to be drilled. Other methods include determining the dielectric constant at microwave frequency (Kabir et al, 1998) and the drill resistance method (Lin et al, 2003). The moisture content of living trees is rarely measured: Kamaguchi et al (2000Kamaguchi et al ( , 2001 determined the moisture content of living trees by the manual impact method.…”

Section: Introductionmentioning

confidence: 99%

Improved methodology of measuring moisture content of wood by a vibrational technique

Taniwaki

Akimoto

Hanada

et al. 2007

Wood Material Science & Engineering

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A method of measuring moisture content of wood is introduced. This method uses a vibrational technique. A shaker driven by swept sine signals was used for the accurate generation of vibration. A cylindrical wood sample was used to verify the method of measuring the moisture content. Resonance frequencies of the wood sample decreased as its moisture content increased. An experiment was performed by measuring the vibration of a tree to explore the feasibility of applying the method to the measurement of the moisture content of trees. The circumferential mode, which is independent of the height of a tree, was identified using a white oak tree.

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Dielectric and ultrasonic properties of rubber wood. Effect of moisture content grain direction and frequency

Cited by 25 publications

References 12 publications

Measurements of Thermal and Dielectric Properties of Medium Density Fiberboard with Different Moisture Contents

Measurements of Thermal and Dielectric Properties of Medium Density Fiberboard with Different Moisture Contents

Effects of Moisture Content and Fiber Proportion on Stress Wave Velocity in Cathay Poplar (Populus cathayana) Wood

Improved methodology of measuring moisture content of wood by a vibrational technique

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