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Aplikace nových materiálů pro tvorbu nábytku budoucnosti s ohledem na uživatelský komfort =: Aplication of new materials for furniture development with respect to user comfort /
Šprdlík, Václav
This thesis was focused on solid wood surface treatments. The goal of the thesis was to achieve superhydrophobic behavior of solid wood surface and its application on furniture design – bathroom furniture. In the first part of experiment the thesis dealt with plasma discharge surface treatment of 3 different wood species – larch (Larix decidua), oak (Quercus robur) and pine (Pinus sylvestris). These treatments were performed in atmospheric and inert (nitrogen) environment with different time of treatment. Effect of plasma discharge was evaluated by contact angle measurement. The second part of the experiment was focused on wax deposition on wooden samples with different roughness. The wax n-hexatriacontane is naturally found as a component of wax blends on the surface of plant leaves. The deposition was performed by physical evaporation in vacuum. This wax has a self-assembly ability, e.g. it creates 3D objects on the surfaces after deposition. The dependence of roughness on self-assembly and wettability in time were examined. Self-assembly ability was observed with scanning electron microscopy and confocal microscopy. Plasmatic treatment hasn´t led to increased hydrophobicity, nevertheless, a significant increase of hydrophilicity was observed during contact angle measurement which could be used as a preparation for surface coating. Surface treatment with wax has led to significant increase of hydrophobicity. Samples of larch and oak achieved superhydrophobic surface behavior (CA > 150°) and pine samples achieved highly hydrophobic behavior (CA > 140°).
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Wood impregnation
Pařil, Petr
Wood impregnation is one of the oldest and the most frequently used techniques to protect the wood. This treatment offers a wide range of protection depending on used impregnants (preservatives). Impregnation can make the wood more resistant to decay, less flammable, more dimensionally stable, harder, stronger, more UV stable resistant and many more. Generally, the aims of this thesis is to give a new and modern approaches to already known technologies. The experimental part have been carried out using laboratory vacuum-pressure impregnation plant and many other devices. Almost all treatments and measurement have been done in laboratories of Research centre in Útěchov. The different wood species e.g. European beech (Fagus sylvatica L.) and hybrid poplar (Populus hybrids) have been studied. The patented solution shows the method of the treatment and colouring of wood containing tannins, characterized by impregnation with a product containing iron oxide nanoparticles, in a concentration of 0.4 g/l to 42 g/l, an average particle size in the range of 1 to 100 nm, and a liquid medium. Impregnation can be performed as pressure impregnation, followed by soaking, or the product can be applied by brushing or spraying. This method is an alternative to wood ammonification. The tests (Paper I) shows following results. Both nanoiron and ammonia treatments tested induced darker colouring of oak wood, more intensive darkening was observed in case of the nano-iron treatment. The native oak showed a steep drop in lightness ca 25-50 hours of exposure followed by gradual re-increase during further exposure to the artificial sunlight. The darker surfaces generated by tannin reacting chemically with iron and ammonia evidently faded in the course of light exposure. In case of chromatic parameters a* and b*, the AT (ammonia treatment) oak more or less copied the colour change progress of native oak. On the contrary, the NIT (nanoiron treatment) wood showed a double increase in both parameters. The colour of NIT wood after light exposure was more or less equivalent to the original colour of the ammonium-treated. Distinct reddening of NIT oak may be caused by oxidation of non-precipitated iron particles. The antifungal effects of copper and silver nanoparticles against two wood-rotting fungi were investigated with following results (Paper II). The highest value of retention was observed for pine sapwood (~ 2 kg/m3) for both nanoparticle solutions. The amount of nanoparticles in the wood did not increase proportionally with an increasing concentration, but only 1.5-2 times increase was reached. An average leaching of 15% to 35% was observed for copper nanoparticles, depending on used wood species and concentration. Significantly lower leaching (max. 15 %) was observed for pine sapwood impregnated by silver nanoparticles with a concentration of 3 g/l. The highest antifungal effect (under 5 % of mass loss) against both tested fungi was found for nano-copper treatment at the concentration of 3 g/l. However, this effect of treatment seems to be almost negligible after the leaching test. Therefore, this study aims to present fundamental material properties of wood treated with copper and silver nanoparticles, and provide groundwork for further research (e.g. fixation of substances in the wood structure, etc.). In this study (Paper III), selected physical and mechanical properties, i.e., density profile, bending strength, hardness and moisture absorption were investigated for Lignamon (i), which was obtained from the Czech industrial production. Selected properties were also investigated using steam-densified beech (ii) and native beech (iii) and compared with each other. Densitometry of Lignamon showed a large variability of the density profile compared to the density profile of only densified beech. It is affected by the degree of densification, temperature and moisture gradients, and their relationship to the glass transition of the wood cell wall. Modulus of elasticity, hardness, moisture exclusion and anti-swelling efficiency of Lignamon are enhanced compared to densified beech. The enhanced dimension stability and lower hygroscopicity of Lignamon are probably caused by heat treatment during the process. Further investigation will be carried out with self-produced Lignamon samples. The paper IV deals with the effect of vacuum-pressure impregnation of poplar wood (Populus alba L.) by aqueous solutions of sucrose and sodium chloride on its physical properties. The most satisfying final properties were achieved in impregnation of sucrose with concentration of 6.25 g/100 ml H2O. The retention was 31 kg/m3 (WPG around 8 %). The values of ASE (anti-swelling efficiency) reached to 36 % and MEE (moisture exclusion efficiency) was reduced by 33 %. In Paper V, MW and conventional acetylation of wood was carried out to determine its efficacy on the material properties. Both MW and conventional heating positively affected the selected material properties. The results showed that no significant differences were found between MW and conventional heating; therefore, MW heating can be used as a valid replacement in the acetylation process. MW power of 2 kW and 0.1 m/min conveyor speed were the optimum conditions for MW acetylation. These process parameters resulted in 39.4 % ASE (T) and 35.2 % ASE (R) for beech and 38.0 % ASE (T) and 16.3 % ASE (R) for poplar samples. This work provides insight into the details of wood acetylation using MW heating. The study (Paper VI) aims to evaluate the antifungal activity of extractive compounds obtained with fexIKA accelerate extraction process. Results showed that the extractive compounds obtained from black locust heartwood were able to increase the native durability of European beech from class 5 (i.e. not durable with an average mass loss of 43.6 %) to class 3 (i.e. moderately durable with an average mass loss of 12.7 %). The final Paper VII shows following results. After impregnation with residual liquids and leaching, high amounts of TT (thermal treatment) and HTC (hydrothermal carbonisation) solution were washed out, whereas Pyrolysis liquids stayed with 25 % to 40 % remaining in the wood. Volumetric swelling in 65 % relative humidity at 20 °C was reduced from 6.5 % in untreated poplar to 5 % in impregnated samples with process residues of thermal treatment using 180 °C or 200 °C. The processes using HTC liquids from Miscanthus sp. (Misc.) or Sawdust showed reduction to 3-3.5 % and Pyrolysis liquid treatment to 2.5 %. After exposure to fungi, the mass loss of untreated Beech (30-35 %) and Poplar (40-50 %) was reduced to 2 % in case of Pyrolysis- and 4 % in case of TT-treatment.
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Tree House - Příbytky v korunách stromů
Kubíček, Miroslav
Theoretical part of the project is comprehensive summary which shows the basic problematics of treehouses and their build-up. It also points to the quality of the build-up by which should be the construction made. The practical part represents a real project of holiday property on specific place set by client. One of the main problem during the creation of the project was to face the treehouse to the perfect valley-view. The benefits of the project are simplicity and possibility to use the treehouse during the winter time. Client had no visual request in advance.
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Návrh roubeného rodinného domu
Slezák, Lukáš
The theme of the thesis is the design and implementation description timbered family house on a particular site. The House will meet the requirements for year-round use family of four. At work, among other things, solves partial basement house, designing perimeter walls of BSH prisms and positioning of the building on a particular site. Solution is also construction of wooden elements of the building and the layout of rooms, depending on orientation to the cardinal. Furthermore, there is described a solution crical details envelope timbered buildings.
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Thermowood properties depending on the protective substances
Kroupa, Michal ; Gaff, Milan (advisor) ; Sarvašová Kvietková, Monika (referee)
Bachelor thesis Thermowood properties depending on the protective substances is divided into several chapters. The first chapter explains the concept ThermoWood, the second chapter focuses on wood modification, the third chapter deals with the properties of wood ThermoWood. The fourth chapter shows the impact on the environment ThermoWood. The fifth chapter focuses on the analysis of literary knowledge, chapter sixth chapter is devoted to the analysis of the use of paints in practice. The penultimate seventh chapter is dedicated to new trends in this area and the last eighth chapter shows the graphs of the Finnish ThermoWood companies that are focused on production statistics.
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Skladování dříví po kalamitních těžbách
Solař, Aleš
The dissertation deals with the verification of the foil storage method influence on wood quality. This method was not explored in our conditions. The dissertation analyzes and specifies the different types of defects that occur during storage, and assesses their impact on the defects during quality of the stored wood during the several years storage period. Based on this assessment reveals the development of individual storage, which cause changes in quality. It explains the causes of quality changes depending on the methods and storage conditions. It sets out the conditions the suitability of the method of storage of raw materials under the foil and specifies the steps in the implementation of this method. The domestic condition is the second area on which work is oriented. They are of use in determining the change in each grade wood assessed under recommended conditions for the measurement and classification of wood in the Czech Republic 2008. The results of this work are significant not just for next research in this field but results can be use directly in practice. The work also includes evaluation of the economic. According to its outcome can be assessed the profitability of this way of storage and protection of wood in real conditions.
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