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Interaction of pulsating water jet with surface of structural materials
Poloprudský, Jakub ; Müller,, Miroslav (referee) ; Chlup, Zdeněk (referee) ; Kruml, Tomáš (advisor)
Pulzní vodní svazek je modifikace konvenčního kontinuálního vodního svazku. Principem technologie je vyvolání rozpadu koherentního vodního proudu na jednotlivé shluky vodních kapek. Shluky působí v momentě dopadu na povrch impaktním tlakem, což významně zvedá erozní vlastnosti proudu. Práce studuje interakci pulzního vodního svazku s povrchem konstrukčních materiálů. Práce se zaměřuje zejména na inkubační erozní etapa. Inkubační erozní etapa se projevuje plastickou deformací povrchu bez přítomnosti makroskopického úběru materiálu. Experimentální typy materiálů jsou austenitické korozivzdorná ocel 316L a hliníková slitina AW-2014. Pulzující vodní proud je poměrně nová technologie s množstvím propojených technologických parametrů. Množství parametrů poskytuje velký prostor pro optimalizaci technologie v závislosti na použití. Předpokládá se, že vodní shluky svazku působí na povrch podobně jako vodní kapky. Na základě tohoto zjednodušení se nabízí použití technologie na testování erozní odolnosti materiálů. Výhoda technologie oproti konvenčním metodám testování eroze je vysoká frekvence dopadu kapek až 40 kHz a možnost kontrolovat rychlost, velikost, úhel a frekvenci dopadajících kapek. Zaměřením práce je zkoumání inkubačního erozního stádia předcházejícího úběru materiálu. Eroze se v tomto stádiu projevuje zdrsňováním povrchu v důsledku plastické deformace materiálu, deformací zrn vedoucímu k odhalování hranic zrn a vytváření povrchového reliéfu uvnitř zrn. Cílem práce je naladění a porozumění fungování pulzního vodního svazku a možné použití technologie pro erozní testování, zdrsňování a zpevňování povrchu. Hlavní dosažená zjištění jsou následující: • Závislost změny distribuce dopadů vodních kapek s několika úrovněmi hydraulických parametrů byla pozorována na obou experimentálních materiálech (hliníková slitina AW-2014 a austenitická ocel 316L). Závislost distribuce dopadů vodních kapek na erozní efektivitu a erozní stádium byla popsána. • Statické erozní testy byly provedeny na oceli 316L. Byly měřeny změny profilu způsobené interakcí s PWJ Podpovrchové změny korespondující se změnami povrchovými byli pozorovány pomocí transmisního elektronového mikroskopu. Bylo definováno erozní stádium mezi zdrsňováním povrchu a makroskopickým úběrem materiálu. Definováno bylo přítomností nespojitých mikro trhlin koncentrujících se zejména na hranicích zrn. • Zpevňování povrchu oceli 316L bylo měřeno na řezu kolmém k ovlivněnému povrchu. Zpevnění bylo pozorované až do hloubky 100 µm, a předcházelo makroskopickému úběru materiálu. • Nárůst únavové životnosti oceli 316L byl změřen po zpracování povrchu pomocí pulzujícího vodního svazku. V rámci zvolených experimentálních parametrů byla pozorována závislost rychlosti přejezdu pulzujícího vodního svazku a počtu cyklů do lomu pro dvě zkoumané úrovně řízené celkové deformace. • Metodologie měření pomocí difrakce zpětně odražených elektronů před a po zpracování povrchu oceli 316L pulzním vodním svazkem byla použita. Metodologie umožňuje měřit vývoj změn v orientaci a deformace uvnitř konkrétních zrn. Otestování metodologie je hlavní příspěvek této práce.
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Posouzení erozního ohrožení vybraných svahů na území podniku Smilkov a.s.
FULÍN, Patrik
The aim of the bachelor thesis is to assess the erosion threat of selected slopes in the territory of the Smilkov a.s. company and the subsequent proposal of anti-erosion measures leading to the reduction of the observed erosion and protection of the surrounding landscape. According to the results, erosion control measures were developed, consisting in the division of the land into parts. Furthermore, an anti-erosion seeding practice was proposed for each soil block. As a result of the erosion control measures, the long-term soil loss was reduced below the permissible soil loss limit.
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Posouzení erozního ohrožení vybraných svahů na území obce Nalžovské Hory
MAREŠ, František
Erosion is a natural phenomena that occurs at different scales in the vast majority of the world. This thesis deals with water erosion in cadastral territory of town Na-lžovské Hory in district Klatovy. In the first part, concept of erosion is described as well as its emergence, causes, effects and protection of the soil by suitable erosion control measures and the specific legislation of the Czech Republic. In the second part of the thesis, selected lands at risk of erosion are assesed according to the information on the LPIS application, followed by using soil erosion calculator to determine appropriate erosion control measures and proper sowing procedures.
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3D Objects Reconstruction from Image Data
Cír, Filip ; Kršek, Přemysl (referee) ; Španěl, Michal (advisor)
This paper deals with 3D reconstruction of objects from image data. There is describes theoretical basis of the 3D optical scanning. Handheld 3D optical scanner setup is described composed of a single camera and a line laser whose position is fixed with respect to the camera. Set of image markers and a simple real-time detection algorithm are proposed. Detected markers are used to estimate position and orientation of the camera. Finally, laser detection and triangulation of points lying on object surface are discussed.
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Using the Erosion Potential Method in the Czech Republic
Hloušek, Jakub ; Larišová, Lucie (referee) ; Dumbrovský, Miroslav (advisor)
The aim of this thesis was the evaluation of the loss of soil for the area of interest, located in the north-western part of the Němčického basin, in the district of Blansko. The calculation was made using two methods, namely erosion potential method (EPM), commonly used in Serbia and the Wischmeier-Smith universal soil loss equation (USLE), used in Czech Republic. Finally, both of these methods were compared with each other. Both methods use a different method of calculation. USLE method utilizes the universal equation for calculating the long-term average soil loss per year (G), the EPM method utilizes equation for specific average annual soil loss (Wsp, Wy). The calculation was performed with both methods in program ArcGIS while the USLE method was also supplemented with calculation of the factor (LS) with USLE2D program. When comparing the soil loss each of evaluated areas, the EPM achieved higher values of soil loss in the most of them. In contrast to the USLE method, the EPM the total loss of the soil from the evaluated areas also accounted the soil loss from forest areas. In terms of accuracy of the achieved real world results, it was determined that the conditions in the Czech Republic are more suitable for the USLE method and not only due to more accurate data input, but also because with EPM there is no factor that would better reflect the topographic factor and conditions of surface runoff in the territory.
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Face detection in image
Pospíšil, Lukáš ; Harabiš, Vratislav (referee) ; Mézl, Martin (advisor)
The main puprose of this paper is to introduce some of algorithms used in face detection in images. This paper focuses on face detection by using a skin-color based segmentation that is computed in three color spectrums (RGB,YCbCr and HSV). This paper also includes software for face detection in pictures and videos.
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Sustainable production capabilities of territory, depending on climatic drought.
Skůpová, Jana ; Uhrová,, Jana (referee) ; Dumbrovský, Miroslav (advisor)
In this work, I dealt with the repercussion of drought on agriculture and land in the cadastral Jinošov. For this area, I analyzed the erosion and ratio of outflow. I also conducted a proposal of adaptation measures against erosion and water retention in the area. In conclusion, I analyzed withholding data and assessed the retention before and after the proposal of adaptation measures. The result of my work is finding that rainfall is inadequate and largely come out of the growing season, that despite all the measures fail to create on the necessary retention for the correct functioning of the landscape. Therefore it is necessary to solve water supply from other areas where is sufficient supply of water.
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Study of runoff and erosion conditions in the Ketkovice cadastral area
Buršík, Lukáš ; Uhrová,, Jana (referee) ; Sobotková, Veronika (advisor)
This Diploma Thesis is focused on the analysis of the Ketkovice cadastral area in terms of runoff and erosion conditions. The QGIS software was chosen for the analysis. For this reason, instructions for this software are prepared, focusing on runoff and erosion conditions, as an appendix to the Diploma Thesis. Other software programs used are USLE2D and DesQ-MaxQ. The first part deals with the analysis of the area of interest. The second part deals with the problem itself, at first the methods used to determine runoff and erosion conditions are introduced, then anti-erosion measures, at the end of this part the software programs used are briefly described. The last third part is devoted at first to the evaluation of runoff and erosion conditions before the design of the measure, then to the design of the measure itself, finally to the evaluation after the design of the measure. In case of erosion conditions, two variants of calculating long-term soil loss are considered before and after the proposed measures. In the first variant, a constant value of the factor R=40 MJ.ha.cm.h is considered in the Universal Soil Loss Equation and in the second variant this value is increased with respect to the climate change.
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Development of New Approaches in Descaling in the Continuous Production of Steel using High-Pressure Water Jet
Votavová, Helena ; Hloch,, Sergej (referee) ; Čecho, Ladislav (referee) ; Pohanka, Michal (advisor)
The thesis summarizes general and up-to-date knowledge of descaling during the continuous production of the hot-rolled steel and proposes further streamlining of this process in industrial production. The first chapter of the thesis deals with the origin, structure and physical properties of the scales. The second chapter describes the principles of descaling by using a high pressure flat water jet. The third chapter introduces the principles of the experimental methods and describes the used laboratory equipment. The fourth chapter summarizes the description of the particular experiments and their evaluation, and thus represents the focus of the dissertation. It is divided into six sections which independently solve predefined objectives of the dissertation. The first section focuses on the height and structure development of the scales on 54SiCr6 and HDT580X steels. It has been proven that the height of the formed scales increases with the time and temperature of the oxidation. The layered nature of the scales was verified at the same time. The second section examines the effect of the nozzle stabilizer on the focussing and distribution of the impact pressure of the nozzle. Experiments have shown that increase of 11 % of an average maximum nozzle pressure can be achieved, depending on the type of nozzle and the length of the stabilizer. The third section deals with the analysis of shadowgraphy images of water jet structures of the nozzles. A script was developed for analysis of these shadowgraphy photos by an adaptive thresholding. The findings are correlated using a regression analysis with an average heat transfer coefficient. It has been reported that most of the standard nozzle configurations produced disintegrated stream of little droplets at the height of the rolled surface. The fourth section focuses on the area of water jet overlap, especially the area of the so-called washout, where the impact pressure of one nozzle is reduced by the nozzle stream of the other. The influence of the pressure change and the mutual displacement of the nozzles is investigated. The analysis showed that the change of pressure did not have any effect on the percentage of reduction of the impact pressure in the area of the washout. It has been shown that if the area of the washout is wide the descaling efficiency in this area may be reduced. The fifth section builds on the previous section and focuses directly on the areas of waterjet overlaps. The influence of the change of rotation and pitch of the nozzles is studied. Experiments have shown that small changes in nozzle pitch do not have a significant impact on impact pressure and heat transfer coefficient. The effect of nozzle rotation, on the other hand, was a significant factor for the efficiency and homogeneity of the descaling of the surface. The last section deals with the effect of the rolling speed on the heat transfer coefficient in the descaling process. The regression model has shown that with a higher rolling speed there is a reduction in the average heat transfer coefficient. Conclusion summarizes the results of the dissertation and proposes which findings can be used in the industry to make the descaling process more effective.
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