Pre-grading of spruce logs containing frozen and unfrozen water by means of frequency-based nondestructive testing (NDT)
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Julia K. Denzler
Abstract
The possibility for pre-grading of logs throughout the year has been evaluated based on dynamic modulus of elasticity (MOEdyn or simplified Edyn) by means of frequency-based nondestructive testing (NDTfreq). The challenge is that Edyn is variable in the frozen, partly frozen, and unfrozen states of logs (state of matter). In the unfrozen state, NDTfreq is reliable if the moisture content does not fall below fiber saturation. The state of the matter was tested via temperature measurements of air and log by means of an infrared technique and sensors, and information was evaluated from NDTfreq. The temperature measurements proved to be inefficient for industrial application because of unreliable data and long measurement times, whereas the NDTfreq measurements allowed the determination of meaningful damping factors. A sufficient level of predictability for more than 60% of the measurements was found. The log measurements in the partly frozen state are inconclusive because Edyn data fluctuate in the presence of both liquid and frozen water. For the completely frozen logs, a correction is introduced as a precaution that avoids an overestimation of Edyn in the unfrozen state.
Acknowledgments
This work was supported by the Austrian Research Promotion Agency (FFG) and Wirtschaftsagentur Wien (ZIT) within the COMET K-project “HFA-TiMBER A.1.2” (project no. 820501). We also thank our project partners Hasslacher Drauland Holzindustrie GmbH and MiCROTEC s.r.l.
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Articles in the same Issue
- Frontmatter
- Original Articles
- Profiles of alkali concentration and galactoglucomannan degradation in kraft impregnation of Scots pine wood: Experimental observations and modeling
- Solvent screening for the fractionation of industrial kraft lignin
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- A new cis-p-coumaroyl flavonol glycoside from the inner barks of Sophora japonica L.
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- Influence of atmospheric pressure plasma treatments on the surface properties of ligno-cellulosic substrates
- Superhydrophobic conductive wood with oil repellency obtained by coating with silver nanoparticles modified by fluoroalkyl silane
- Wettability and swelling of acetylated and furfurylated wood analyzed by multicycle Wilhelmy plate method
- Pre-grading of spruce logs containing frozen and unfrozen water by means of frequency-based nondestructive testing (NDT)
- Cork structural discontinuities studied with X-ray microtomography
Articles in the same Issue
- Frontmatter
- Original Articles
- Profiles of alkali concentration and galactoglucomannan degradation in kraft impregnation of Scots pine wood: Experimental observations and modeling
- Solvent screening for the fractionation of industrial kraft lignin
- Pilot-scale demonstration of SPORL for bioconversion of lodgepole pine to bioethanol and lignosulfonate
- Interrelationship between lignin-rich dichloromethane extracts of hot water-treated wood fibers and high-density polyethylene (HDPE) in wood plastic composite (WPC) production
- A new cis-p-coumaroyl flavonol glycoside from the inner barks of Sophora japonica L.
- Modification of poplar wood with glucose crosslinked with citric acid and 1,3-dimethylol-4,5-dihydroxy ethyleneurea
- Influence of atmospheric pressure plasma treatments on the surface properties of ligno-cellulosic substrates
- Superhydrophobic conductive wood with oil repellency obtained by coating with silver nanoparticles modified by fluoroalkyl silane
- Wettability and swelling of acetylated and furfurylated wood analyzed by multicycle Wilhelmy plate method
- Pre-grading of spruce logs containing frozen and unfrozen water by means of frequency-based nondestructive testing (NDT)
- Cork structural discontinuities studied with X-ray microtomography
