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Influence of kind of wood for quality of selected paints for exterior
Blažek, Tomáš ; Pánek, Miloš (advisor) ; Zeidler, Aleš (referee)
The aim of the diploma thesis is to provide lay persons as well as specialists in the field with information about a suitable surface treatment method for various types of wood and about the impact of the choice of wood on the coating durability when used outdoors, so that they make a sound judgement upon these findings. The diploma theses is divided into several parts containing an introduction into the problem of degradation of wood used outdoors, a description of various coatings based on natural substances, various wood modifications, principles of applying the coatings, norms providing for applying the coatings. On the basis of the tests using accelerated aging it has been found that the best results had oak with chemical modification Lignofix I-profi and final surface finish with the application of outdoor oil. The aim of the thesis is to compare selected coatings based on natural substances on selected types of modified wood. Outputs of particular tests are clearly arranged to provide a clear overview of particular measurement data. The diploma thesis also includes a clear analysis of particular coating materials with respect to their acquisition costs compared to their degradation and their utility.
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Impact of Silvicultural Measures on Some Mechanical Wood Properties of Scots Pine
Schönfelder, Ondřej ; Zeidler, Aleš (advisor) ; Bílek, Lukáš (referee)
The purpose of this study is to assess the impact of silvicultural measures on selected mechanical properties of Scots pine of the area Doksy and Plasy. Each area is characterized by growths that are typical for the locality. From areas Doksy were selected 3 stands and 2 from Plasy region. For each crop were chosen representative of the trees that were cut down, and testing material was produced. On test samples was determined density at 12 % level moisture, modulus of rupture, modulus of elasticity, toughness and compression strength in the fiber direction. All tests were carried out by standardized procedures. Using statistical methods, it was found that a statistically significant value of compared areas were only in the density. The others properties which were examined in the areas are statistically insignificant. However, when assessing individual stands with ANOVA was generally for the most of properties found statistically significant difference. This suggests that the pine wood properties are dependent on location. In horizontal plane strain was found a statistical significance for all of the tested characteristics. That shows that the position of the wood in the stem has impact on the mechanical properties. Furthermore, the individual results were evaluated in terms of dependence on the density. Which resulted in the majority of cases middle to high dependency.
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Selected Physical Wood Properties of Douglas Fir from Sites in the Czech Republic
Chvojka, Jan ; Zeidler, Aleš (advisor) ; Podrázský, Vilém (referee)
This diploma thesis was created to evaluate of selected physical properties, density and shrinkage of Douglas-fir (Pseudotsuga menziesii / Mirbel / FRANCO) wood, coming from areas of Lesy města Písku, s.r.o. and the territory of School Forest Enterprise in Kostelec nad Černými lesy of Czech University of Life Sciences. The work tested density and shrinkage, their subsequent comparison with native species and the relevant data from the regions of original distribution of these species. It was also assessed if these physical properties are affected by location of growth or if they vary between individual trees and what is the effect of horizontal or vertical position in a stem on the tested values. It was shown that the density reaches higher values than our native trees. It was found that location of growth or individual trees have influence on the tested properties. The value of density is decreasing with growing height of the tree and increasing with growing distance from the center of the tree. Shrinkage in tangential direction was lower in comparison with Scotch pine, but higher in radial direction. Volumetric shrinkage reached lower values than Scotch pine.
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Evaluation of Impact Strength and Bending Strength of Thermally Modified Beech Wood with the False Heartwood
Vykoukal, Jakub ; Zeidler, Aleš (advisor) ; Procházka, Jiří (referee)
This bachelor thesis examines the influence of thermal modification on beech wood, with taking into account the difference of properties of healthy samples and samples with false heartwood. Thermal modification took place in two stages (165 ° C and 210 ° C), which are together with the untreated set tried on impact strength, bending strength (static modulus of elasticity) and the dynamic modulus of elasticity. The additional measured properties were density, equilibrium moisture and change of color spectrum. The first level of treatment slightly increased the bending strength and the static modulus of elasticity, residue tests, however, showed a negative effect on the other measured properties of the heat treated samples. It has been shown also that false heartwood has a clearly negative effect on the measured mechanical properties.
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Selected Mechanical Wood Properties of Douglas Fir from Sites in the Czech Republic
Pilař, Ondřej ; Zeidler, Aleš (advisor) ; Holeček, Tomáš (referee)
Abstract
Introduced tree species are still undoubtedly, despite the current short-term politico-economic and environmental turbulences, an object of interest of the Czech forestry sector. Worldwide the most important tree species, and thus both in the areas
of its original extension and in the large regions where it was successfully introduced,
is the Douglas fir (Pseudotsuga menziesii), which is considered as one of the most perspective tree species. Information about the quality of its wood from our territory
is missing for the time being.
That´s why the aim of this work was to evaluate the quality of Douglas fir wood from different regions of the Czech Republic through selected mechanical properties. Especially the compressive strength, impact strength, flexural modulus and flexural strength were determined by standardized procedures. As well as, the variability
of the trunk features and that one of the locality were taken in consideration.
The final results of the mechanical features compared with the values measured on the wood from the original extension areas are better in compression strength, similar in flexural strength and slightly worse in the flexural modulus.
Comparing the resultant values of Douglas fir with the values of domestic spruce, the Douglas fir shows better values, apart from the values of flexural modulus, which are higher in case of the spruce.
A statistically significant difference between the location and the measured feature is demonstrated only in the elastic modulus and density. At the variability
in frame of the trunk there was found a statistically significant difference between
the vertical and horizontal position of the trunk and all the measured features. At the same time, the value of the measured feature increases together with increasing position from the pulp.
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