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Pevnost vybraných konstrukčních spojů s použitím modifikovaného dřeva buku
Valíčková, Lenka
The thesis focuses on the influence of selected European beech wood modifications (Fagus sylvatica L.), i.e. acetylation and thermal modification at 200 °C and 220 °C, on the strength of structural joints used in the furniture industry. Based on the literature research, three types of structural joints were selected, which were subsequently tested. The strength of the glued joint was tested according to ČSN EN 205, withdrawal capacity of a screw according to ČSN 49 0135 and the corner screw joint. The results of the measurements were statistically evaluated using a one-way ANOVA and the measured groups were compared to each other. The results demonstrate that all types of modification lead to a decrease in mechanical strength. Wood acetylation lead to a statistically significant differences in the values for the glued joint. The thermal modification at 200 °C achieved statistically significant differences in the withdrawal capacity of a screw. The biggest drop in values came after a thermal modification at 220 °C, which were statistically significantly different when testing all selected joints. In the case of acetylation and heat modification up to 200 °C, it is not possible to unequivocally identify a method that showed significantly better results across all tests. Both metods of modyfying wood showed possibilities of use in furniture design. However, a decrease in the mechanical properties ofthe modifies material muse be taken into account when determining the dimensions of the structure.
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Posouzení možnosti využití buku v materiálech na bázi dřeva a ve výrobcích
Horníček, Stanislav
The thesis deals with the assessment of the possibilities of using wood in wood-based materials and products. Part of this thesis is a list of basic wood-based materials used in timber construction. Furthermore, assessment of possibility and explanation of wood modification principles. The thesis includes the design of functional element of the product and also experiment examining selected physical properties of the modified beech wood. The aim is to create a basic overview of trends in production, products and in the use of wood-based materials and possibilities of the use of beech wood for these products and materials.
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Barvení rostlého dřeva manganistany - změna barvy a její světlostálost
Šípek, Jan
This bachelor thesis developed in the form of the experiment deals with the possibilities and potential of wood colour modification by nanomangan particles. Colour change, its dependencies and light permanency have been examined. The subject for this work has recently been developed wood mordant TAIRON (Pařil et al., 2016), the same principles and processes were followed in effort to reach similar results. For investigation the oak wood has been chosen for its high content of tannins. Oak wood samples were reused from previous experimentation Modification of wood colour by iron nano-particles (Kmoníčková, 2018). Nano-mangan particles solution was originated and applied, afterwards colour change was measured and discussed. Nano-mangan solution evoke darkening of wood surface, however the total colour change, compared with other modification (TAIRON, Amonia fuming), is insufficient and unexploitable. Therefore, light permanency was examined on samples modified by nano-ferric solution.
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Modifikace barvy dřeva nanočásticemi železa
Kmoníčková, Petra
This thesis clarifies the influence of the content of polyphenolic substances on the color change of oak and larch wood after the modification of surface by iron. The samples were modified by solution of iron nanoparticles at two different concentrations. After that the change of color components was determined. The analysis of polyphenols by Folin-Ciocalteu by spectrophotometric method was made for each sample and also dry matter in the extracts was determined. The final data were subjected to statistical analysis and correlation and regression analysis were performed. Statistically significant correlations for both species were found.
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Vliv tepelné modifikace na vybrané vlastnosti bukového dřeva tlakově impregnovaného přírodními oleji
Daněk, Václav
Present study aims to analyze thermal modification of beech wood (Fagus sylvatica L.) press-impregnated by natural oil and its influence on physical and mechanical properties of wood. Beech wood was press-impregnated by hemp oil (O 1000) and thermally modified at 200°C for 3 hours. Influence of certain treatment (i.e. oil impregnation, thermal modification, combination) was experimentally investigated using physical and mechanical tests. Color changes (CIELab system), dimensional stability and bending strength were experimentally measured and results compared with reference group. Results of given work was further discussed and compared with literature. Results shows increase of dimensional stability about 18% after thermal modification (TM) and 22% for oil impregnated and thermally modified wood (OL+TM). Mechanical performance (bending strength) decreased about 5,2% after thermal modification as a results of degradation of wood cell wall. On the other hand, strength increase about 9% for wood impregnated by oils. Combined processed provide results within similar range as reference. Results should be further discussed and parameters of process (temperature levels) as well as influence of various oils parameters (drying, semi-drying, nondrying) tested in future.
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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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Milling process analysis of thermally modified wood
Dvořák, Ondřej ; Sarvašová Kvietková, Monika (advisor) ; Gašparík, Miroslav (referee)
The work is focused on the characteristics of the milling process of thermally modified wood as a new type of material with an innovative internal structure achieved by heat and humidity treatment. The work is divided into three parts. The first part focuses on the theoretical summary of the method of milling and a brief analysis of various types of the process. The second part specializes in description of thermally modified wood as the new technical material. The final part deals with the influence of properties of "thermowood" on milling process.
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Trends in the design and creation of new materials
Kašičková, Václava ; Gaff, Milan (advisor) ; Babiak, Marian (referee)
Thesis investigates the flexural properties of modified laminated wood. Thesis examined two wood species - beech and aspen. The aim was to describe effect of wood species, material thickness, densification, adhesives and loaded cyclic stress on selection of mechanical properties.
Wood species and thickness of material were determined as factors with very significant impact. They affected modulus of elasticity, limit of proportionality and bending strength. All these characteristics achieved higher values while testing beech lamellas. Degree of densification does not appear as a very significant factor. Comparing modulus of elasticity in this thesis and data given in the literature it is possible to say that densified lamellas used in this research reached higher values.
This thesis also investigates tensile-shear strength and bendability.
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Porovnání hydrotermické a chemické plastifikace dřeva
Rousek, Radim
The process of wood plasticization and densification has been known for decades. It is used for improvement of mechanical properties of low density wood. The objective of this study is to compare two different methods of wood plasticization. Specimens made of European beech wood (Fagus sylvatica) were plasticized by hot steam or gaseous ammonia and then compressed in tangential direction. Stress-strain behaviour during compression was evaluated. In this study influence of growth ring angle on densification process was also investigated. Gaseous ammonia at a pressure of 0.2 MPa was less efficient than hot steam. The best plasticizing effect was reached by combining these two methods. A growth ring angle of 15° from direction of compression (almost tangential) was evaluated as the best for densification of European beech wood.
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