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Influence of Plasma-nitriding on Fatigue Life of High-strength Steels under Biaxial Loading
Major, Štěpán ; Kohout, Jan (referee) ; Růžička,, Milan (referee) ; Obrtlík, Karel (referee) ; Pokluda, Jaroslav (advisor)
This work deals with fatigue life and fractographycal analysis of plasma-nitrided and virgin specimen made of the low-alloy high-strength steel. Specimens were subjected to in-phase combined bending-torsion loading. The work is focused on three groups of problems. The first group of problems was associated with the fatigue life and its prediction. The objective was to examine a relationship between the presence of the nitrided layer and fatigue life. The application of surface layers has significantly improved the fatigue life in the high-cycle region. An extended comparison between classical and advanced multiaxial criteria was performed. Criterions proposed by Marin and Matake were found to be most precise. The second objective of this work was to examine a relationship between the loading ratio ( is the bending amplitude and is the torsion amplitude ) and the fracture surface topography in the highcycle fatigue. Properties of fracture surfaces were quantified by many roughness and fractal parameters. Many roughness parameters start to incrise rapidly above a critical value of the loading ratio zc = 0,5. The last part of this work deals with the fractographical analysis of fish-eye cracks that were formed in plasma-nitrided steel specimens under symetrical bending, symetrical torsion and biaxial in-phase bending-torsion combinations.
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"Fisheye" Camera Projection
Macík, Pavel ; Juránek, Roman (referee) ; Seeman, Michal (advisor)
The thesis describes theoretical fundamentals of optics and problems of ray-tracing method, ray-triangle intersection computation included. Next section describes concept of three different camera models for ray-tracing method - plain camera, pinehole camea and spherical camera (fish-eye). The thesis comparse properties and capabilities of camera models and their effect to projected image of a scene. The program for raytracing was implemented for purposes of the thesis including implementation of camera models described in the thesis.
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Generation of realistic skydome images
Špaček, Jan ; Wilkie, Alexander (advisor) ; Pilát, Martin (referee)
Generation of realistic skydome images We aim to generate realistic images of the sky with clouds using generative adversarial networks (GANs). We explore two GAN architectures, ProGAN and StyleGAN, and find that StyleGAN produces significantly better results. We also propose a novel architecture SuperGAN which aims to generate images at very high resolutions, which cannot be efficiently handled using state-of-art architectures. 1
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Relationship of assimilation of forest stands to interception in selected watersheds
Macounová, Kristina ; Vlček, Lukáš (advisor) ; Chuman, Tomáš (referee)
The main topic of the submitted bachelor thesis is the assessment of the leaf area index (LAI) by means of hemispherical photographs. Its text is also occupied with the interception as the additional use of hemispherical scanning. The measurements took place in several forest stands. The territories of interest are situated in the catching basin of the brook Rokytka in the Czech National Park Šumava, in the Tetřivčí potok (Grouse Creek) surroundings, in the contiguity of the village Zbytiny (Prachatice district) and in the German National Park Bayerischer Wald. The text includes characterization of habitats in which the field measurements were carried out, and describes the measurement techniques. Key words: Leaf area index (LAI), interception, hemispherical photographs, fisheye
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"Fisheye" Camera Projection
Macík, Pavel ; Juránek, Roman (referee) ; Seeman, Michal (advisor)
The thesis describes theoretical fundamentals of optics and problems of ray-tracing method, ray-triangle intersection computation included. Next section describes concept of three different camera models for ray-tracing method - plain camera, pinehole camea and spherical camera (fish-eye). The thesis comparse properties and capabilities of camera models and their effect to projected image of a scene. The program for raytracing was implemented for purposes of the thesis including implementation of camera models described in the thesis.
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Influence of Plasma-nitriding on Fatigue Life of High-strength Steels under Biaxial Loading
Major, Štěpán ; Kohout, Jan (referee) ; Růžička,, Milan (referee) ; Obrtlík, Karel (referee) ; Pokluda, Jaroslav (advisor)
This work deals with fatigue life and fractographycal analysis of plasma-nitrided and virgin specimen made of the low-alloy high-strength steel. Specimens were subjected to in-phase combined bending-torsion loading. The work is focused on three groups of problems. The first group of problems was associated with the fatigue life and its prediction. The objective was to examine a relationship between the presence of the nitrided layer and fatigue life. The application of surface layers has significantly improved the fatigue life in the high-cycle region. An extended comparison between classical and advanced multiaxial criteria was performed. Criterions proposed by Marin and Matake were found to be most precise. The second objective of this work was to examine a relationship between the loading ratio ( is the bending amplitude and is the torsion amplitude ) and the fracture surface topography in the highcycle fatigue. Properties of fracture surfaces were quantified by many roughness and fractal parameters. Many roughness parameters start to incrise rapidly above a critical value of the loading ratio zc = 0,5. The last part of this work deals with the fractographical analysis of fish-eye cracks that were formed in plasma-nitrided steel specimens under symetrical bending, symetrical torsion and biaxial in-phase bending-torsion combinations.
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Výpočet radiace v lesních porostech na základě dat leteckého laserového skenování
Patočka, Zdeněk
Leaf area index (LAI) is the most important variable influencing the penetration of solar radiation beams through the forest stand. Currently, the airborne laser scanning, as new indirect method, suggests itself for estimation of LAI. LAI was measured terrestrially using the hemispherical photographies analysis and compared with LiDAR Penetration Index - LPI. There were created several regression models describing the dependence of LAI and LPI with coefficients of determination from 0.71 up to 0.81. Leaf area index was also applied to the Beer-Lambert law for calculation of the solar radiation in forest stands. Practical application possibilities of LPI in forestry (estimation of stocking, optimization of shelterwood cuttings etc.) have been described in conclusion of this diploma thesis.
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