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Träs svällning på mikro- och makronivå

Grönvold, Marie (2016)
LTH School of Engineering in Helsingborg
Abstract
The aim of this study was to examine if the radial swelling of wood correlated with the density of the wood. The aim was also to investigate whether the area of the lumen changed from dry to water-saturated state for wood with different densities. Two different experiments were performed. In the first experiment a light microscope was used to examine different species of wood. The wood samples were photographed with a magnification of ×400 and the cells could be identified at an individual level, first in a water-saturated state then completely dry. The images were analyzed and the swelling coefficient was calculated (for the radial direction). The change in area of the lumen was also measured as well as the change of the cell wall area.... (More)
The aim of this study was to examine if the radial swelling of wood correlated with the density of the wood. The aim was also to investigate whether the area of the lumen changed from dry to water-saturated state for wood with different densities. Two different experiments were performed. In the first experiment a light microscope was used to examine different species of wood. The wood samples were photographed with a magnification of ×400 and the cells could be identified at an individual level, first in a water-saturated state then completely dry. The images were analyzed and the swelling coefficient was calculated (for the radial direction). The change in area of the lumen was also measured as well as the change of the cell wall area. In addition, the swelling between two fixed points was determined. The second part of the experiment was to measure the radial swelling, from water-saturated state to completely dry, was measured at a macroscopic level using larger specimens (10×10×10 mm3). The results from the two experiments were analyzed and compared with each other and literature values for radial swelling. The result from the microscopic study shows that the lumen area of the cells could both decrease and increase. There is a tendency that for wood with lower density the lumen area increased, from dry to water-saturated state, while for wood with higher density the lumen area decreased. It was an almost linear correlation. However, there was a large spread within each species and further studies must be made to ensure a correlation. The study showed that there is some correlation between the radial swelling of wood and its density, but it was not completely linear. The difference in fiber saturation point for the different species probably had an impact, but it could also be due to the change in lumen size or both. Measuring the radial swelling by selecting two fixed points was a good method and the values corresponded very well with literature values. Swelling coefficients from the macroscopic measurements were slightly higher than literature values, which may be due to the difficulties in measuring in a pure radial direction. One of the biggest challenges was to find a method that would result in good images, where individual cells could be identified and then find the exact same part of the wood after drying. The method used in the experiment worked very well although it was time consuming. The method could be further developed to provide even better images for studying swelling of wood. (Less)
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author
Grönvold, Marie
organization
year
type
M2 - Bachelor Degree
subject
keywords
svällningskoefficient, radiell svällning, densitet, trä, lumen
language
Swedish
id
8892431
alternative location
https://portal.ch.lu.se/Campus.NET/Services/Publication/Export.aspx?id=2933&type=doc
date added to LUP
2016-09-26 04:08:10
date last changed
2016-09-26 04:08:10
@misc{8892431,
  abstract     = {The aim of this study was to examine if the radial swelling of wood correlated with the density of the wood. The aim was also to investigate whether the area of the lumen changed from dry to water-saturated state for wood with different densities. Two different experiments were performed. In the first experiment a light microscope was used to examine different species of wood. The wood samples were photographed with a magnification of ×400 and the cells could be identified at an individual level, first in a water-saturated state then completely dry. The images were analyzed and the swelling coefficient was calculated (for the radial direction). The change in area of the lumen was also measured as well as the change of the cell wall area. In addition, the swelling between two fixed points was determined. The second part of the experiment was to measure the radial swelling, from water-saturated state to completely dry, was measured at a macroscopic level using larger specimens (10×10×10 mm3). The results from the two experiments were analyzed and compared with each other and literature values for radial swelling. The result from the microscopic study shows that the lumen area of the cells could both decrease and increase. There is a tendency that for wood with lower density the lumen area increased, from dry to water-saturated state, while for wood with higher density the lumen area decreased. It was an almost linear correlation. However, there was a large spread within each species and further studies must be made to ensure a correlation. The study showed that there is some correlation between the radial swelling of wood and its density, but it was not completely linear. The difference in fiber saturation point for the different species probably had an impact, but it could also be due to the change in lumen size or both. Measuring the radial swelling by selecting two fixed points was a good method and the values corresponded very well with literature values. Swelling coefficients from the macroscopic measurements were slightly higher than literature values, which may be due to the difficulties in measuring in a pure radial direction. One of the biggest challenges was to find a method that would result in good images, where individual cells could be identified and then find the exact same part of the wood after drying. The method used in the experiment worked very well although it was time consuming. The method could be further developed to provide even better images for studying swelling of wood.},
  author       = {Grönvold, Marie},
  keyword      = {svällningskoefficient,radiell svällning,densitet,trä,lumen},
  language     = {swe},
  note         = {Student Paper},
  title        = {Träs svällning på mikro- och makronivå},
  year         = {2016},
}