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- Vaziri, Mojgan, et al.
(författare)
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Magnetic resonance imaging of water distribution in welded woods
- 2011
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Ingår i: Journal of Adhesion Science and Technology. - Utrecht : VSP. - 0169-4243 .- 1568-5616. ; 25:16, s. 1997-2003
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Tidskriftsartikel (refereegranskat)abstract
- This study was performed for a better understanding of water effect on welded wood and improving its water resistance. In this article, we have also attempted to demonstrate the feasibility of using Magnetic Resonance Imaging technology to study water movement in welded woods. Water distribution in welded woods of Scots pine (Pinus sylvestris) and beech (Fagus sylvatica) was investigated by Magnetic Resonance Imaging. Axial specimens were cut from beech and sapwood of Scots pine in longitudinal direction of wood grain. Two pieces of each wood species were welded together by a linear vibration machine. Sub-samples measuring 30 mm x 20 mm x 100 mm were cut from the welded specimens for Magnetic Resonance Imaging. The results showed that weldline of Scots pine was more resistant to water than weldline of beech. Pine joint was still holding after 40 h immersion in water, while a rapid wetting of the beech joint resulted in breakage of the joint in even less than an hour. This preliminary study also showed that MRI is a powerful tool to measure water distribution in welded woods and highlighted the potential of this technique to enhance understanding of wood welding. (C) Koninklijke Brill NV, Leiden, 2011
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| 2. |
- Adebahr, J, et al.
(författare)
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Ion and solvent dynamics in gel electrolytes based on ethylene oxide grafted acrylate polymers
- 2002
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Ingår i: The Journal of Physical Chemistry Part B. - : American Chemical Society (ACS). - 1520-5207 .- 1520-6106 .- 1089-5647. ; 106:47, s. 12119-12123
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Tidskriftsartikel (refereegranskat)abstract
- Multinuclear pulsed field gradient NMR measurements and theological viscosity measurements were performed on three series of polymer gel electrolytes. The gels were based on a lithium salt electrolyte swollen into a copolymer matrix comprising an acrylate backbone and ethylene oxide side chains. In each series the side chains differed in length and number, but the acrylate-to-ethylene oxide ratio was kept constant. It was found that the self-diffusion coefficient of the cations was much lower than that of the anions, and that it decreased rapidly when the side chains got longer. In contrast, the self-diffusion coefficient of the anions was found to be independent of chain length. In the gel electrolytes, the diffusion coefficients of the solvent molecules are relatively constant despite an increased viscosity with increasing length of the side chains. However, in saltfree gels made for comparison, the diffusion coefficients of the solvent molecules decreased with, increasing length of the side chains, which is consistent with an increased viscosity.
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