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Preparation of nanocrystalline ceramic materials made from zirconia oxide
Vlček, Ondřej ; Prajzler, Vladimír (referee) ; Šťastný, Přemysl (advisor)
Bachelor thesis is focused on preparation of nanocrystalline stabilized zirconia ceramics. The theoretical part is dedicated to zirconia ceramics. Theoretical part describes and unveil the transformation-induced toughening mechanism in partially stabilized zirconia ceramics, the processing routes of these ceramic materials and their utilization. The research part describes preparation of yttria partially stabilized nanocrystalline zirconia ceramics by slip casting method.
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Optimization of simulation parameters in the process of spraying a metal die
Vlček, Ondřej ; Šotka, Pavel (referee) ; Krutiš, Vladimír (advisor)
This thesis, prepared for Škoda Auto, deals with the optimization of die casting simulation parameters in software ProCast. The aim was to develop and validate a methodology for inputting die spray parameters. The optimization itself was performed on a high pressure die casting simulation for an engine block casting. The temperature field was taken from the real die using a thermographic camera and then compared with the simulation. The parameters of the simulation were adjusted according to the experimentally obtained data and literature, and the course of optimization required changing not only the parameters related to the external treatment, but also the material models, or changing the heat transfer coefficient between the die and the casting. By the procedure, the temperature field of the original simulation, which differed from reality by more than 100 °C, was optimised so that the results at the measured locations did not reach a difference of more than ± 20 °C. Therefore, the procedure used can be applied as the required methodology for optimising further simulations.
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Blender Add-on for Simulation of Water Erosion
Vlček, Ondřej ; Milet, Tomáš (referee) ; Chlubna, Tomáš (advisor)
The aim of this thesis is adding terrain erosion functionality to Blender. The solution presented here implements hydraulic erosion based on textures and the use of the graphics card. Compared to other existing solutions this add-on utilizes parallel processing, offers an alternate workflow for erosion and creates additional information usable in further rendering of the model.
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Optimization of simulation parameters in the process of spraying a metal die
Vlček, Ondřej ; Šotka, Pavel (referee) ; Krutiš, Vladimír (advisor)
This thesis, prepared for Škoda Auto, deals with the optimization of die casting simulation parameters in software ProCast. The aim was to develop and validate a methodology for inputting die spray parameters. The optimization itself was performed on a high pressure die casting simulation for an engine block casting. The temperature field was taken from the real die using a thermographic camera and then compared with the simulation. The parameters of the simulation were adjusted according to the experimentally obtained data and literature, and the course of optimization required changing not only the parameters related to the external treatment, but also the material models, or changing the heat transfer coefficient between the die and the casting. By the procedure, the temperature field of the original simulation, which differed from reality by more than 100 °C, was optimised so that the results at the measured locations did not reach a difference of more than ± 20 °C. Therefore, the procedure used can be applied as the required methodology for optimising further simulations.
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Preparation of nanocrystalline ceramic materials made from zirconia oxide
Vlček, Ondřej ; Prajzler, Vladimír (referee) ; Šťastný, Přemysl (advisor)
Bachelor thesis is focused on preparation of nanocrystalline stabilized zirconia ceramics. The theoretical part is dedicated to zirconia ceramics. Theoretical part describes and unveil the transformation-induced toughening mechanism in partially stabilized zirconia ceramics, the processing routes of these ceramic materials and their utilization. The research part describes preparation of yttria partially stabilized nanocrystalline zirconia ceramics by slip casting method.
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The origin of air pollution on the basis of one year measurements of PM2.5 and PM10 at two urban background stations in Prague
Schwarz, Jaroslav ; Pokorná, Petra ; Rychlík, Š. ; Škáchová, H. ; Smolík, Jiří ; Ždímal, Vladimír ; Vlček, O. ; Hůnová, I.
The particulate matter (PM) mass concentration in cities corresponds to the sum of the concentrations measured at the background stations and the difference between the city and background stations. For this reason, at high background concentrations of PM, the result of emission reduction measures is low. Most of the reported episodes of increased PM concentrations in winter in central European cities are caused by sources of local or regional origin from the combustion of coal and / or biomass for heating purposes. Improvement of air quality in cities is possible provided that causality is understood, especially when it comes to atmospheric aerosol and its concentration, sources and origin.\nThe aim of the work was to determine the origin of air pollution in Prague on the basis of one year parallel measurements of atmospheric aerosol at two urban background stations.\n\n
Fulltext: content.csg -  PDF
Plný tet: SKMBT_C22020011314370 - PDF
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Air Pollution Origin Based on One-year PM2.5 and PM10 Measurement at Two Suburban Sites in Prague.
Pokorná, Petra ; Schwarz, Jaroslav ; Rychlík, Š. ; Škáchová, H. ; Smolík, Jiří ; Ždímal, Vladimír ; Vlček, O. ; Hůnová, I.
The objective of this study was to determine air pollution origin in Prague based on the chemical composition of 24h atmospheric aerosol (AA) samples collected in parallel for one-year at two suburban sites. Chemical analysis of PM2.5 and PM10 for elements by ICP-MS, for elemental and organic carbon by thermo-optical method and water-soluble inorganic ions by IC was performed. The AA in Prague air shed was well mixed and nine common PM10 sources of local, urban, regional and long range transport (LRT) origin were apportioned.
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22018110212471 - PDF
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Design of the new generation integrated emission model
Resler, Jaroslav ; Juruš, Pavel ; Benešová, N. ; Vlček, O. ; Belda, M. ; Huszár, P. ; Krč, Pavel ; Eben, Kryštof
The only publicly available and widely used tool for emission modelling for CTM is the processor SMOKE (Coats & Carlie, 1996), but its usage is limited by its strong dependence on conditions of USA. A few attempts to adjust SMOKE to other conditions were made in the past - see e.g. works reported in Bieser et al., 2011 or Borge et al., 2008, but the efforts hit the limits of its design. Our goal is to develop an emission processor based on open technologies which will be easy to use for typical usage with CTM in our conditions and which will be flexible and configurable enough to serve specific needs of users in other countries over the world.
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Modelling assessment of scenarios of urban development to air quality and thermal comfort at street level
Resler, Jaroslav ; Krč, Pavel ; Belda, Michal ; Juruš, Pavel ; Benešová, N. ; Vlček, O. ; Damašková, D. ; Eben, Kryštof ; Derbek, P.
A new model for simulations of urban environment USM was developed and integrated into LES model PALM inside the project UrbanAdapt. The model allows simulations of air flow, radiation, air temperature and temperature of materials, air pollution and indices MRT and PET in fine resolution. The surrounding of a crossroad of the streets Komunardu and Delnicka in Praha-Holesovice was chosen as a pilot area in collaboration with IPR Prague. Studied scenarios included changes of housing development as well as assessment of different types of plant canopy and sensitivity studies of the colour of walls, roofs, streets and pavements.
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Development and validation of the new model of thermal conditions of urban environment in fine resolution
Resler, Jaroslav ; Krč, Pavel ; Belda, Michal ; Juruš, Pavel ; Benešová, N. ; Lopata, J. ; Vlček, O. ; Damašková, D. ; Eben, Kryštof ; Derbek, P. ; Maronga, P. ; Kanani-Sühring, F.
The assessment of different scenarios of the city development to air quality and thermal comfort in the areas of street canyons was our main goal inside the project UrbanAdapt. It follows the need for a model which allows to simulate air flows in fine resolution of the order of meter and realistically predict turbulence in the complex terrain of streets and buildings. The LES models comply with such requirements but the review showed that there was no free available LES model which could model the energy exchange in urban environment, i.e. the interaction of energy and air flows including effects of vegetation and different properties of urban surfaces and materials. Thus we decided to extend the existing LES model PALM by a new module USM (Urban Surface Model) which describes the most important energy exchanges in the urban environment. The validation of the model was done against observations obtained by IR camera in the course of heat wave episode in July 2015.
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