High Resolution Measurement of the Surface Layer Moisture Content during Drying of Wood Using a Novel Magnetic Resonance Imaging Technique
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A. Rosenkilde
Summary
The moisture content profile in the surface layer of Scots pine (Pinus sylvestris) sapwood has been measured using the MRI (Magnetic Resonance Imaging) technique.Anovel high-gradient permanent magnet was used for the measurement of the moisture profile in the wood during the drying process, giving a depth resolution of better than 20 μm. This paper demonstrates for the first time the possibility of measuring the moisture content depth profile in the surface layer from raw state down to 4% moisture content without removing the wood sample from the apparatus. The main advantage of this technique and apparatus is a high resolution over a large field of view. It is possible to measure the moisture content in the wood surface layer during drying up to a depth of 300 μm. A single moisture content profile may be obtained in less than 5 min. Hence, more accurate dynamic drying information, on a single sample, maybe achieved than with current techniques. In this preliminary studywe observed that the wood cells at the surface had a moisture content higher than the equilibrium moisture content for wood in the surrounding bulk air. We conclude that for a wood moisture content of above approximately 50% the resulting profiles were almost flat from a depth of 90 μm and further into the wood and in between the surface and 90 μm deep there was a steep gradient. Below 50% there was a gradient in moisture content to at least 300 μm depth.
Copyright © 2002 by Walter de Gruyter GmbH & Co. KG
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Articles in the same Issue
- Weight Loss and Cell Wall Degradation in Rubberwood Caused by Sapstain Fungus Botryodiplodia theobromae
- Changes of EPR Spectra of Wood Impregnated with Copper-Based Preservatives during Exposure to Several Wood-Rotting Fungi
- Quantitative Analyses of Morphological Variation of Cross-Sectional Tracheids of Hinoki (Chamaecyparis obtusa Endl.) Near Knot by Image Processing
- Direct Effects of Wood Characteristics on Pulp and Handsheet Properties of Eucalyptus globulus
- Identification of the Lignan Nortrachelogenin in Knot and Branch Heartwood of Scots Pine (Pinus sylvestris L.)
- Chemical Composition of Lipophilic and Phenolic Constituents of Barks from Pinus nigra, Abies bornmülleriana and Castanea sativa
- Pinus pinaster Oleoresin in Plus Trees
- Determination of Polyphenolic Content of Bark Extracts for Wood Adhesives
- Softwood Bark Pyrolysis Oil-PF Resols. Part 2. Thermal Analysis by DSC and TG
- Softwood Bark Pyrolysis Oil-PF Resols. Part 3. Use of Propylene Carbonate as Resin Cure Accelerator
- Steam Explosion of Aspen Wood. Characterisation of Reaction Products
- Characterization of Black Liquors from Soda-AQ Pulping of Reed Canary Grass (Phalaris arundinacea L.)
- Modification of the Nitrogen Content and C:N Ratio of Sitka Spruce Timber by Kiln and Air Drying
- High Resolution Measurement of the Surface Layer Moisture Content during Drying of Wood Using a Novel Magnetic Resonance Imaging Technique
- Longitudinal Permeability and Diffusivity of Steam in Beech Determined with a Wicke-Kallenbach-Cell
- UF/pMDI Wood Adhesives: Networks Blend versus Copolymerization
