<abstract xmlns="http://www.w3.org/1999/xhtml">

Wood moisture content (MC) has a significant impact on all electrical properties of wood. Regarding the development of the (so-called polarization-type) wood moisture meter with the electrical charging effect for monitoring and controlling the wood drying process, it is of interest to expand the theoretical background of this type of novel wood moisture meter by means of modelling. Two mediums were selected for modelling – raw birch wood and, as a reference medium, birch liquid sap – into which two symmetrical carbon fibre measuring electrodes were inserted. In both mediums, direct current and alternating current were passed between electrodes at different electrode potentials. The electrical field and electrical response of the current-affected mediums were then measured and modelled in the time domain and frequency domain. The numerical results of modelling are comparable both in the time domain and frequency domain (i.e. if E = 1.8V, then Cs = 0.5 mF and C1,int = 0.7 mF). The concept of energetic chargeability (CHA(W)) of wood was defined and compared to conventional chargeability as defined by C. Schlumberger in 1913. Empirical dependencies of CHA(W) on electrode potential and primary energy W1 transmitted through the wood (sap) medium were found. In the frequency domain, frequency dependencies were found to distinguish between adsorption processes and mixed kinetics ranges in birch sap and in raw birch wood.
</abstract>

Wood moisture content (MC) has a significant impact on all electrical properties of wood. Regarding the development of the (so-called polarization-type) wood moisture meter with the electrical charging effect for monitoring and controlling the wood drying process, it is of interest to expand the theoretical background of this type of novel wood moisture meter by means of modelling. Two mediums were selected for modelling – raw birch wood and, as a reference medium, birch liquid sap – into which two symmetrical carbon fibre measuring electrodes were inserted. In both mediums, direct current and alternating current were passed between electrodes at different electrode potentials. The electrical field and electrical response of the current-affected mediums were then measured and modelled in the time domain and frequency domain. The numerical results of modelling are comparable both in the time domain and frequency domain (i.e. if E = 1.8V, then Cs = 0.5 mF and C1,int = 0.7 mF). The concept of energetic chargeability (CHA(W)) of wood was defined and compared to conventional chargeability as defined by C. Schlumberger in 1913. Empirical dependencies of CHA(W) on electrode potential and primary energy W1 transmitted through the wood (sap) medium were found. In the frequency domain, frequency dependencies were found to distinguish between adsorption processes and mixed kinetics ranges in birch sap and in raw birch wood.

Investigation and modelling of the electrical charging effect in birch wood above the fibre saturation point (FSP)

Forestry Studies

This work is licensed under the Creative Commons Attribution 4.0 International License.

Kasepuidus elektrilise laadumise efekti uurimine ja modelleerimine niiskussisaldusel üle kiu küllastuspunkti

Wood moisture content (MC) has a significant impact on all electrical properties of wood. Regarding the development of the (so-called polarization-type) wood...

Investigation and modelling of the electrical charging effect in birch wood above the fibre saturation point (FSP)

Article Category: Research paper

Pubblicato online: 04 mag 2023

Pagine: 21 - 37

Ricevuto: 03 dic 2022

Accettato: 28 dic 2022

DOI: https://doi.org/10.2478/fsmu-2022-0010

Parole chiave
above FSP, chargeability of wood, energetic chargeability of wood

© 2022 Valdek Tamme et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Investigation and modelling of the electrical charging effect in birch wood above the fibre saturation point (FSP)

Article Category: Research paper

Pubblicato online: 04 mag 2023

Pagine: 21 - 37

Ricevuto: 03 dic 2022

Accettato: 28 dic 2022

DOI: https://doi.org/10.2478/fsmu-2022-0010

Parole chiaveabove FSP, chargeability of wood, energetic chargeability of wood

© 2022 Valdek Tamme et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Parole chiave
above FSP, chargeability of wood, energetic chargeability of wood