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Hustotní profil a jeho vliv na vlastnosti třískových desek
Matyáš, Michal
The goal of this thesis is to determine properties of manufactured particleboards with different percent content of recycled wood. The objective was to determine density values, thickness swelling, moisture content, internal bonding, bending properties and vertical density profile of particleboards. The research question was to report the effect of different percent content of recycled wood on final properties of particleboard. The own method was established and various particleboards produced. The properties of materials were tested according to EN standards and by descriptive statistics, analysis of variance (ANOVA) and linear regression evaluated. In summary in research it was observed that percent content of recycled wood has little impact on final properties of particleboard, although there were several factors which may have affected these results. These factors are described in this thesis.
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Stanovení mechanických vlastností konstrukčního lepeného hranolu z bukového dřeva
Kománek, Martin
The aim of this thesis is to experimentally assess the wood of the European beech (Fagus sylvatica, L.) with regard to the possibilities of its use in the building industry. For this purpose, were made test samples in the form of solid and glued beams measuring 100 x 100 x 1000 mm. Half of the beams were soaked for thirty days in the water for w highter than MH, the other half was conditioned for long time under conditions equilibrium wood moisture stabilized at a humidity of = 12 %. The wooden beams were subjected to a symmetrical 3-point and 4-point bending test according to ČSN EN 408+A1 (2012). Examine mechanical characteristic were a strength limit of a bending, an elasticity modulus of the bending and a shear elastic modulus determined also from the bending test. According to our experiment, the shear moduli of elasticity with high scatter values and therefore statistically insignificant. Flexural modulus values were obtained for massive with w = 12%, 7 858 MPa, for massive with w highter than MH prisms 3 724 MPa, for prisms glued with polyurethane adhesive Lear D4 with w = 12%, 7 693 MPa and for prisms bonded with phenol formaldehyde adhesive Lignofen G/3/D with w = 12%, 7 853 MPa. The strength of the beams were delivered for massive with w = 12%, 79 MPa, for massive w highter than MH, 41 MPa, for beams glued with polyurethane adhesives Lear D4 with w = 12%, 83 MPa and for bonded phenol formaldehyde glue with w = 12%, 73 MPa. The above values were influenced by many factors such as density, moisture, wood defects, or the quality of prisms gluing.
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