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Analýza mechanického chování konstrukčního masivního a lepeného hranolu z bukového dřeva
Musil, Tomáš
The aim of the work was to describe the influence of humidity and behaviour of solid and laminated squared timber including also the type of glue on mechanical behaviour of wooden beams. On production of beams sized 100 × 100 × 1 000 mm3 was used beech wood (Fagus sylvastica L). One half of beams was under water for about 30 days, the other half was left without soacking. The mechanical behaviour of beams, strained by 4-pointed symetrical bending, was analyzied by using relations between tensions and deformations, from which were gained the characteristics of strenght and elasticity wich are modulus of elasticity, modulus of rupture the bend on specific level of strain. Advanced analysis of deformation field was accomplished by the method of digital imagine correlation. The statistic tests for deflection and neural axis not prove statisticly significant results. only with wet beams were statisticaly significant results despite others, in case of statistic tests for modulus of elasticity and modulus of rupture. At coprasion modulus of elasticity from optics and testing machine were statisticaly significant results only group Laminated beams dry red and solid beams wet.
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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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Povrchové úpravy podlah z materiálu na bázi dřeva ve veřejném interiéru
Kroutilová, Šárka
This diploma thesis deals with the issue of appropriate surface treatment for wooden floors in public interiors. The materials used in this thesis are coniferous (spruce) and foliate (beech and oak) types of wood which has been treated with four different kinds of transparent coating. The evaluation of the most appropriate coating for a particular kind of wood is based on laboratory experiments focused on physical-mechanical, chemical and microbiological properties.
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Lze využít samoprořeďování buku v pěstování lesů?
Homola, Petr
The thesis deals with the use of the process of self-spinning in growing beech stands. The classical method of growing beech stands is described in the available literature, which focuses on the process from restoration to educational interventions in rods. The literature review also mentions a selective method in beech farming. Furthermore, the process of self-dilution is outlined, where the operation of this process is described. The methodological part includes preparatory work, fieldwork and office work, each of which is sent as it was done, whether in the office or in the field. Field work includes, for example, measuring the height and thickness of trees, measuring the height of the crown deployment, determining the quality level of the tree. The office work includes the processing of acquired data from the field into a clear database. Furthermore, data from this database were analyzed for the results. In the final part there is an evaluation of the results, which will help us to tell whether and, if so, under what conditions can this method be used in forestry practice or not.
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Zhodnocení ujímavosti a vitality prostokořenného a krytokořenného sadebního materiálu
Hrabal, Jan
This thesis evaluates ability to root and vitality of bare rooted and containerized planting stock of European beech (Fagus sylvatica L.), Douglas fir (Pseudotsuga menziesii Mirb.) and Norwegian spruce (Picea abies L.). The aim of thesis was to find out which king of planting stock is better for interest species. The measurement took place on 4 areas near Zelená Hora village, on a foot of Drahanská vrchovina. These parameters were mea-sured: tree height, height increase in 2015, crown width, crown shape, stem deflection, length of needles, length and width of leaf, root neck thickness and vitality. The result of thesis is evaluation of individual parametres and comparison of bare rooted and con-tainerized planting stock.
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Natural regeneration in relation to different gap sizes
Hiitola, Nina Maria
The goal of this diploma thesis was to assess the spatial and temporal development of natural tree regeneration in forest openings, in the temperate forest types of South Moravia, Czech Republic. Relationships between micro-site conditions and seedling growth were analysed, with focus on gap size, light conditions and soil environment. Ten different semi-circular gaps, ranging from 0.02 hectares to 0.13 hectares in size, were included for carrying out sampling. The sampling followed a long-term research set up in 2013 by the Training Forest Enterprise Masaryk Forest Křtiny. The regeneration census focused on identifying prevalent species and recording their density and height class, in relation to their position in a canopy gap. Beech (Fagus sylvatica), Norway spruce (Picea abies) and silver fir (Abies alba) were the prevailing target species with varied mixed compositions, suggesting management favourability towards selection systems and irregular shelterwood system due to the high functioning level of shade tolerant tree dynamics.
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Rozměrová stabilita a borcení konstrukčního masivního a lepeného dřeva z buku
Pecháčková, Pavlína
The aim of the thesis is to compare swelling and collapsing of structural massive and laminated wood of beech. Prisms of size 10x10x1000 mm are for 30 days submerged in water. Thereafter the experimental values of swelling are settled and also are settled the coefficients of swelling and transverse and longitudinal collapsing. The repercussions of beech wood by solid prisms and effect of glue and individual plates with glued blocks are analysed. In our experiment, the values are larger volumetric swelling in solid wood and in tangential, radial and longitudinal swelling the opposite is true. Cross warping achieves higher values for laminated prisms and longitudinal collapsing has been measured only in solid samples.
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Posúdenie vplyvu použitia univerzálneho vrutu a vrutu novej generácie s klzným povlakom
Martečík, Marek
Thesis deals with the assessment of the impact of using the classic universal screw and screw the new generation with a sliding coating on various aspects of the production process. It was judged mainly possibility to join two operations into one: pre-drilling and screwing. This opportunity of screws the new generation would mean omission of pre-drilling at joints in hard hardwood, which would result in savings in labor time and costs for making joints. This option would therefore have a major impact on the economic factor in the production of furniture. Furthermore, it was determined the strength of cordless drill screwdriver needed to tighten screws into hardwoods - beech, and watched the wear on drill bits of cordless screwdriver associated with increased effort on tools of missed pre-drilling operation. This issue relates, for example, the manufacture of chairs, supporting frames of upholstered furniture as well as garden furniture or wooden constructions. During the tests it was used solid beech wood, as a classic representative of the hardwood deciduous wood, widely available and often used in the manufacture of furniture. The focus of this work was to observe the characteristics of the three selected types of wood screws in two dimensions. The results of observations and measurements were noted, photographically documented, analyzed and evaluated.
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Návrh materiálu na bázi dřeva s požární odolností
Jeřábková, Lucie
Bachelor thesis compares the properties of composite materials with basalt fiber or with glass fiber. The main objective is comparison of the mechanical properties, which include fire resistance. Concretely, thesis will deal with bending properties of composite material with basalt fiber. These properties of composite material with basalt fiber will be compared with the bending properties of the composite material with glass fiber and plywood. The second part will deal with fire resistance of composite material with basalt fiber and will compare with the fire resistance plywood and composite material with glass fiber. Finally will be made a test of the surface resistant against falling bullet.
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Nasycení dřeva pryskyřicí a vliv na mechanické vlastnosti
Večeřa, Zdeněk
The subject of the thesis is to clarify the influence of saturation of wood with resin on its mechanical properties. The selected tree species is beech. From the samples of beech I've created three groups, of which two groups were saturated with resin and one was unsaturated. Groups saturated with resins are further subdivided into saturated with synthetic and natural resins. The groups were compared with each other. The samples of all groups were subjected to experimental tests, which involve determining the compression across the fibers. The obtained data were subjected to statistical analysis.
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