Thermal and dielectric properties of pine wood in the transverse direction

Kol, Hamiyet Şahin

doi:10.15376/biores.4.4.1663-1669

Cited by 20 publications

(4 citation statements)

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“…As a consequence, the treated wood has a lower water affinity (Herrera et al 2014). This indicates that water uptake and absorption in wood slow down, so the amount of water in the wood decreases (Hill 2006;Gu and Hunt 2007;Sahin Kol 2009;Sahin Kol and Sefil 2011). The k-value of water is much higher than wood, so the k-value tends to increase as EMC increases or decreases as EMC decreases.…”

Section: Resultsmentioning

confidence: 99%

Thermal conductivity temperature dependence of heat-treated wood at different moisture content levels

Kol

Vaydoğan

2023

BioRes

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Effects of temperature dependence and relative humidity were studied relative to the thermal conductivity of heat-treated pine and heat-treated beech, which are frequently used for building construction. Pine and beech wood were exposed to heat treatment at 180, 200, and 220 °C in nitrogen gas for 2 h. As a result, the thermal conductivity values of the heat-treated wood decreased as the temperature of the heat treatment process increased and relative humidity increased. However, thermal conductivity of wood became more stable after heat treatment under relative humidity changes. The thermal conductivity values increased with rising mean plate temperatures, while the temperature dependence of the heat-treated wood was not affected by the relative humidity changes. Consequently, heat-treated wood, with variable humidity without excessive heat changes, can be preferred for the construction of buildings.

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Section: Resultsmentioning

confidence: 99%

Thermal conductivity temperature dependence of heat-treated wood at different moisture content levels

Kol

Vaydoğan

2023

BioRes

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“…Based on the weight gain results for control WS, WS-LG, WS-LG/TO, WS-LG/EG, and WS-LG/TO/EG composites, it can be concluded that thermal conductivity at 23 • C/50% for all compositions is almost unaltered due to the hygroscopic nature of control WS and the increased hydrophobicity of LG, LG/TO, LG/EG, and LG/TO/EG coated WS composites. In other words, as control WS is more prone to moisture, its thermal conductivity increases, as Kol [32] and Troppová et al [33] revealed that the thermal conductivity of pine wood significantly increases under different moisture contents. The moisture content in wood or wood particles increases water molecules within the wood or wood particles matrix.…”

Section: Constant Coefficients In Equationsmentioning

confidence: 91%

Performance Analysis of Loose-Fill Thermal Insulation from Wood Scobs Coated with Liquid Glass, Tung Oil, and Expandable Graphite Mixture

et al. 2023

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The current study presents the results of monitoring the behavior of loose-fill thermal insulating material for buildings made of wood scobs (WS), which were coated with one, two, and three component-based coatings from liquid glass (LG), tung oil (TO), and expandable graphite (EG). The thermal conductivity of samples in the dry state and under normal laboratory conditions, short-term water absorption by partial immersion, surface wettability, and water vapor permeability were evaluated, and regression equations describing the variations in numerical values of specified properties under different amounts of each coating component were presented. It was shown that LG and TO act as hydrophobic layers that, in conjunction, reduce water absorption by a maximum of 274%, have a contact angle equal to 86°, and lower thermal conductivity by 55% in the dry state due to the specifics of the layer formed on the surface of WS. The addition of EG to LG coating resulted in insignificantly changed water absorption and thermal conductivity values, indicating the potential of this material to be used to improve the fire resistance of wood-based composites in the future. The results showed that the three-component layer of LG/TO/EG reduces water absorption by a maximum of 72%, increases thermal conductivity in the dry state by a minimum of 0.4%, and increases the contact angle to 81° at 100 wt.% LG. The changes in water vapor permeability of all compositions were determined to be insignificant.

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“…The wood powder comprises cellulose, lignin, hemicellulose, and other substances that respond differently to electric field frequency. When the moisture content of wood powder approaches 0, under the force of an external electric field, the direction of the electric moment of the internal dipoles of wood powder shifts towards the direction of the external electric field, arranged according to the direction of the electric field, resulting in the relative displacement of the electric moment, leading to directional polarization (Kol 2009). However, as the frequency increases, the polar molecules inside the wood powder are quickly polarized.…”

Section: Infrared Spectroscopy Measurement Analysismentioning

confidence: 99%

Dielectric characteristics of poplar powder under high-frequency electric field

Zhou

2023

BioRes

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Dielectric properties of poplar tree powder were measured at frequencies from 5 to 30 MHz. The effects of moisture content, frequency, and bulk density on the dielectric constant and dielectric loss factor were analyzed. The polar groups of wood powder were characterized by infrared spectroscopy to reveal the response mechanism of wood powder in the high-frequency electric field. The results showed that, in general, wood powder’s dielectric constant and dielectric loss factor increased with increasing bulk density and moisture content. In the moisture content range from 0 to 24%, the dielectric constant ε’ of wood powder decreased with the frequency increase with 5 MHz as the maximum value of ε’. When the moisture content was 0 ≤ w < 20%, wood powder’s dielectric loss factor ε” varied as a quadratic function with increasing frequency, corresponding to a maximum value of ε” at 13.4 to 17.7 MHz. When the moisture content was >20%, the dielectric loss factor ε” of wood powder decreased linearly with increasing frequency, and the maximum value of ε” was 5 MHz. The infrared spectrum showed that the polar groups in the wood powder were mainly -OH, C=O, C-O, and -CH, with the highest percentage of -OH.

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Thermal and dielectric properties of pine wood in the transverse direction

Cited by 20 publications

References 0 publications

Thermal conductivity temperature dependence of heat-treated wood at different moisture content levels

Thermal conductivity temperature dependence of heat-treated wood at different moisture content levels

Performance Analysis of Loose-Fill Thermal Insulation from Wood Scobs Coated with Liquid Glass, Tung Oil, and Expandable Graphite Mixture

Dielectric characteristics of poplar powder under high-frequency electric field

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