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Development of a strategy for 3D printing of copper using Laser Powder Bed Fusion
Kryšpín, Vojtěch ; Vaverka, Ondřej (referee) ; Malý, Martin (advisor)
Copper sees vast usage in aeronautical, electrotechnical and energy industries due to its excellent machinability and thermal and electrical conductivity. In combination with modern computational approaches such as topological optimalization, additive manufacturing of copper has a great potential. My work has focused on creating a sample with the highest relative density through the application of recoating and remelting strategies. The best specimens which reached relative density over 99,1% were created with the following printing parameters: LP = 400 W, LV = 400 m·s-1 a HD = 0,01 mm.
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Processing of compact polycrystalline YAG ceramics
Kaplan, Lukáš ; Pouchlý, Václav (referee) ; Kachlík, Martin (advisor)
In the literary part of this master thesis a research on various methods of preparation of dense polycrystalline YAG ceramics and the effects of sintering on the densification and other desired properties of such prepared YAG ceramics was carried out, the transparency after addition of dopant elements was also discussed. In the experimental part of the thesis, samples of dense polycrystalline YAG ceramics were prepared by SSR method and the effect of sintering on the densification and porosity of the YAG ceramic samples was studied. Relative density, porosity, phase purity and transparency were measured on the sintered samples. These measurements were compared with the results of the works reported in the literature section.
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Processing of high-strength aluminum alloy EN AW 7075 using SLM technology
Skalický, Petr ; Hudák, Radovan (referee) ; Koutný, Daniel (advisor)
This diploma thesis deals with processing of high strength aluminum alloy EN AW 7075 by Selective Laser Melting and verify the influence of process parameters on relative density and mechanical properties. The theoretical part contains an introduction to additive manufacturing of aluminum alloys, the influence of process parameters and description of processes occuring during SLM production. Based on the theoretical part were prepared experiments and method of evaluation. Samples were produced by melting metallurgical powder using ytterbium laser with a maximum output power of 400 W. This diploma thesis also describes the formation and growth of cracks inside the material, which so far in the literature for alloy EN AW 7075 were not described. As the result, the process parameters dependence on the relative density and an overview of this aluminum alloy processing by SLM technology is determined.
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Creation of CAD data for structured parts
Kolář, Dominik ; Krčma, Martin (referee) ; Vaverka, Ondřej (advisor)
Lattice structures are a subset of cellular structures used, for example, for topological optimization of components produced by additive manufacturing. However, the design of the structures is very demanding in classical CAD (computer-aided design) modellers. One of the specialized software for structure design is nTop. This thesis describes the creation of a workflow in nTop to create structures with a combination of unit cell types defined by relative cell density. The creation of the workflow consisted of several parts. First, the unit cells of the structure were designed. Then, using polynomial interpolation in Matlab, the relative density to member diameters conversions were made, and finally a procedure for combining the different cell types into a single part was designed. Thus, the resulting workflow allows to build a part of any shape consisting of different cell types determined by relative density.
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Processing of compact polycrystalline YAG ceramics
Kaplan, Lukáš ; Pouchlý, Václav (referee) ; Kachlík, Martin (advisor)
In the literary part of this master thesis a research on various methods of preparation of dense polycrystalline YAG ceramics and the effects of sintering on the densification and other desired properties of such prepared YAG ceramics was carried out, the transparency after addition of dopant elements was also discussed. In the experimental part of the thesis, samples of dense polycrystalline YAG ceramics were prepared by SSR method and the effect of sintering on the densification and porosity of the YAG ceramic samples was studied. Relative density, porosity, phase purity and transparency were measured on the sintered samples. These measurements were compared with the results of the works reported in the literature section.
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Development of a strategy for 3D printing of copper using Laser Powder Bed Fusion
Kryšpín, Vojtěch ; Vaverka, Ondřej (referee) ; Malý, Martin (advisor)
Copper sees vast usage in aeronautical, electrotechnical and energy industries due to its excellent machinability and thermal and electrical conductivity. In combination with modern computational approaches such as topological optimalization, additive manufacturing of copper has a great potential. My work has focused on creating a sample with the highest relative density through the application of recoating and remelting strategies. The best specimens which reached relative density over 99,1% were created with the following printing parameters: LP = 400 W, LV = 400 m·s-1 a HD = 0,01 mm.
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Ecological traits as a correlates of spatial variation in abundances of a Czech birds
Farkač, Jan ; Hořák, David (advisor) ; Reif, Jiří (referee)
Jan Farkač, Diplomová práce 2018 Abstract Bird species differ in their local densities, which seems to be related to their geographical distribution and species-specific traits. Investigating such a relationship can help us to understand better how the birds inhabit the space. The aims are as follow (i) to take an alternative approach to densities by counting them just in species preferred habitats and (ii) to explain the abundance characteristics such as an absolute density, variation in local densities or occupancy by species-specific traits. The relationship between abundance characteristics (local densities and their coefficient of variation in space) and avian traits such as a habitat specialisation, diet specialisation, PCA of morphological traits, PCA of reproduction traits - as an estimate of slow-fast continuum and a range size were tested using GLM. There are two abundance characteristics significantly related to species specialisation index. I have used the data from the Common Bird Monitoring Program run in the Czech Republic by the Czech Society of Ornithology. Due to the highest amount of records I have selected data from the year 2009 and subsequently species occupying more than 50 transects (out of 129), which resulted in inclusion of 47 species into analyses. This thesis contains...
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Processing of high-strength aluminum alloy EN AW 7075 using SLM technology
Skalický, Petr ; Hudák, Radovan (referee) ; Koutný, Daniel (advisor)
This diploma thesis deals with processing of high strength aluminum alloy EN AW 7075 by Selective Laser Melting and verify the influence of process parameters on relative density and mechanical properties. The theoretical part contains an introduction to additive manufacturing of aluminum alloys, the influence of process parameters and description of processes occuring during SLM production. Based on the theoretical part were prepared experiments and method of evaluation. Samples were produced by melting metallurgical powder using ytterbium laser with a maximum output power of 400 W. This diploma thesis also describes the formation and growth of cracks inside the material, which so far in the literature for alloy EN AW 7075 were not described. As the result, the process parameters dependence on the relative density and an overview of this aluminum alloy processing by SLM technology is determined.
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