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Optimization of methods for determining the durability of wood coating systems
Škvařil, Michael ; Žák, Antonín (referee) ; Vaněrek, Jan (advisor)
The bachelor thesis deals with the optimization of methods for determining the durability of wood coating systems. The theoretical part deals with a detailed analysis of wood coating systems, including the specification of their composition, especially with a focus on modern water-borne coating systems. In the practical part an experiment was carried out, where on the selected types of coatings applied to lumber was performed analysis of selected durability parameters of coatings after exposure to short-term and long-term exposure to degradation factors
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Progressive types of formwork with anticorrosion protective function
Marek, Martin ; Vaněrek, Jan (referee) ; Drochytka, Rostislav (advisor)
The corrosion of the reinforcement is the main cause of malfunction of the reinforced concrete. It causes meaningful increase of liveness of the construction. The subject of this thesis is development of progressive concrete reinforcement with anticorrosive protective function. Theoretical part is focused on study and description of available corrosion inhibitors, mainly migrating inhibitors. Theory also includes summary of the principles of concrete reinforcement corrosion. The purpose of the thesis is application of migrating corrosion inhibitors to the formwork and basic testing of their efficiency.
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Influence of material base of coating systems onto wood durability
Bednářová, Ilona ; Petránek, Vít (referee) ; Vaněrek, Jan (advisor)
The thesis deals with the influence of the base material of the coating systems for wood durability when we exposed them to external conditions. The theoretical part is devoted to wood durability and weather resistance with a detailed description of the tests the durability of coating systems. A substantial part of the theory is devoted to description binder component of the coating material. In the practical part was performed the experiment, which examined the influence of the thickness of the coating system, the type of coating material (paint or lasure) as well as the type of binder (water dispersion with an alkyd or acrylic resin, respectively solution coating system with the alkyd resin). All coating systems were exposed to natural and artificial durability tests. The criterions for evaluation were chosen differences of colours.
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Analysis of methods for determining wood moisture by non-destructive methods
Změlík, Jiří ; Zach, Jiří (referee) ; Vaněrek, Jan (advisor)
Subject of this bachelor thesis is the analysis and comparison of hygrometers considering their price, availability and applicability. Theoretical part compared available types of hygrometers based on their operating principle. Subsequently, resistance, capacitive and microwave portable hygrometers were compared in more detail. There were five reviewed hygrometers in total, with three of them capacitive and one of each resistance and microwave. The measurement was performed on beech and spruce trees at gravimetrically known humidity, ranging from extremely low to extremely high values (even out of bounds recommended by the manufacturer). The evaluation of the methods was performed according to the Saaty´s AHP method. Hygrometers were then selected by their optimization. After the experimental part, the suitability of individual methods was determined. The best method was capacitive, followed by resistance and the worst microwave method.
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Study of adhesive penetration into the wood cell wall
Janová, Petra ; Krbila, Jaromír (referee) ; Vaněrek, Jan (advisor)
This labor is based on penetration of adhesive into a wood cell walls. It focuse on adhesives basicly used for construction purposes, especially on epoxy resins. The labor contains the use of methods for precise detection adhesive in wood and methodics for choice of adhesive and wood basically used for bonding. It describes the experimentally detected dependence of contact angle on viscosity epoxy resins.
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Durability of glued joints of structural timber elements
Mlčák, Tomáš ; Vejpustek, Zdeněk (referee) ; Vaněrek, Jan (advisor)
This bachelor thesis deals with the topics of durability of glued connections of structural wooden elements. The theoretical part of the work deals with the construction of wood, selected defects of wood, a description of carpentry joints and fasteners. The work also pays attention to adhesives and sealants used in glued joints of wooden structures or the issue of crack repair systems in wood. The practical part of the work is focused on experimental verification of the durability of used adhesives and sealants for glued carpentry elements.
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Wood microstructure analysis onto the strength parameters
Martinek, Radomír ; Kuklík,, Pavel (referee) ; Vaněrek, Jan (advisor)
This work focuses on a closer examination of the microstructure of wood and the relationship between microscopic and mechanical properties of wood. The main point of the practical part of this study is a measurement of microfibril angle (MFA) in the S2 layer of a wood cell wall. This layer occupies more than 80 % of the total thickness of the cell wall and thus has the greatest influence on the mechanical properties of the wood cells. MFA values as well as values of bulk density show a strong dependence on the modulus of elasticity in the longitudinal direction, as well as on the values of shrinkage. The theoretical part involves methods for measuring MFA, variations of MFA, wood properties evolving from the MFA and also mechanical properties of wood cell walls measured by nanoindentation.
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Study of durability of wood glue bonds against increased temperature
Kučera, Vít ; Vejpustek,, Zdeněk (referee) ; Vaněrek, Jan (advisor)
In this time are for design of wooden elements available simplified procedures for fire modeling which defines ČSN EN 1991-1-2. But it is not experimentally tested the impact of adhesive on the final value of fire resistance of laminated panels. This diploma thesis solves basic normative practices that could explain the durability of glue bond against increased temperatures. in the practical part will be undertaken to experimentally assess the impact of various kinds of adhesive-based (epoxy, formaldehyde, PUR and EPI) on the glued bond durability against increased temperature. Glued joints that will be subjected to gradual temperature exposure in order to assemble the dependence of the temperature influence on the final strength of the joint according to the type of adhesive.
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Development of wood-based board materials applying thermal modification process
Buriánek, Vlastimil ; Pipíška,, Tomáš (referee) ; Vaněrek, Jan (advisor)
This diploma thesis deals deals with the effectiveness of polyurethane and phenol-resorcinol-formaldehyde adhesives when applied in bonded joints of thermally treated sheet materials. The thermal resistance of commercially used adhesives was analysed as part of a research activity. Furthermore, the changes in the properties of wood materials after heat treatment were described. In the practical part, the effectiveness of the used adhesives on densified birch plywood was verified with respect to the shear strength of the resulting composite. Based on the results obtained, it was proceeded to verify the effectiveness of densification on spruce plywood.
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