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Study of the selected properties of aluminium alloys with Yb and Zr addition
Zikmund, Sebastien ; Vlach, Martin (advisor) ; Mathis, Kristián (referee)
The presented thesis focuses on the effect of addition of ytterbium, manganese and zir- con in alloys AlYb and AlMnYbZr in the state as casted, cold rolled with the deformation degree of 40 % and 70 % and after high-temperature annealing. The materials were exa- mined with the methods of electrical rezistometry, differential scanning calorimetry and microhardness measurements. The characterization of the examined alloys was completed by a parallel research of the microstructure with the methods of transmission and scanning electron microscopy, electron diffraction and electron backscatter diffraction. A positive influence of the addition Mn and Zr and cold rolling was proven at hardening of the mate- rials. In the context of messurement error a different influence in the microhardness of the materials was not observed among the different degrees of cold roling deformation. The si- multaneous addition of Mn and Zr has a positive effect on the size of the grain, whereas the size of the grain at the as prepered state was determined in millimetres (in AlYb) and in hundres of mictometers (AlMnYbZr). On the border of (sub)grains an eutetic phase rich in Yb, Fe (or more precisely Yb, Mn, Cu, Fe for the alloy AlMnYbZR) was observed for both alloys. At the annealing temperature around 400 řC, an additional...
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Phase transformation in magnesium MgZnAl-based alloys
Kodetová, Veronika ; Vlach, Martin (advisor)
In the present work, there was analyzed thermal evolution of the phase transformation in the MgZnAl and MgZnAlCa alloys with different concentration of the Zn and Ca. The grains were occupied by the phase with quasicrystaline icosaedral structure in the as-cast alloys and after isochronal annealing up to 240 řC. The thermal measurements revealed two exothermic effects in the MgZnAl alloy and three exothermic effects in the MgZnAlCa alloy during linear heat treatment in the temperature range of 100 - 250 řC. In agreement to the thermal response, two and three stages of electrical resistivity decrease were observed in the same temperature range. The lower thermal changes, absolute resistivity changes and microhardness were observed in the alloy with Ca-addition and lower concentration of Zn.
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Visuality of gender performativity in the films of Xavier Dolan
Vlach, Martin ; Baslarová, Iva (advisor) ; Kolářová, Kateřina (referee)
The aim of this diploma thesis is to explore the way how the gender performativity is portrayed in Xavier Dolan's films. The theoretical part of the thesis first deals with the definition and theoretical grounding of gender performativity from the perspective of several authors, mainly Judith Butler. This part of the thesis will detailly introduce the concepts of gender performativity, which will be necessary for the analysis of the studied films. The theoretical part also presents the queer theory and the related chapter devoted to queer film, which would also include Dolan's work. Lastly, this part also includes a chapter devoted to the concept of mise-en-scène. The methodological part introduces the method of semiotic analysis and introduces the synopsis of the studied films. The analytical part of the work presents its own semiotic analysis of the examined films. The aim of the analytical part is to find out how Dolan works with gender performativity in his films and how it is visually portrayed.
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Precipitation processes in light hardenable alloys and the possibilities for integrating thermal analysis into physics education on high school
Kodetová, Veronika ; Vlach, Martin (advisor) ; Černošková, Eva (referee) ; Svoboda, Pavel (referee)
The doctoral thesis is divided into two parts - Thermal analysis in physics education on high school and Material research of Al-Zn-Mg(-Cu-Sc-Zr) alloys. Within the first part, the areas of crystallization and/or melting of selected foods were determined using differential scanning calorimetry. A practical lesson for high school physics has been created and tested. The study text focused mainly on differential scanning calorimetry and its use was made. In the second part of the doctoral thesis, there was analysed thermal evolution of the phase transformation in the Al- Zn-Mg(-Cu) alloys with Sc and Zr addition. The effect of (cold and hot) deformation on the decomposition sequences was studied. The hardening effect after annealing above 300 řC in the Sc and Zr alloys is caused by the precipitation of the secondary Al3Sc,Zr) particles. These particles were observed by transmission electron microscopy after annealing up to 360 řC in all studied AlZnMg(Cu)ScZr alloys. In the AlZnMgCu alloy the partial recrystallization was observed after annealing at 350 řC/10 hours and after annealing at 450 řC/10 hours the grain size was 50-200 m (depending on the treatment of the alloy). The addition of Sc, Zr in the AlZnMgCuScZr stabilizes grains and there is no recrystallization in the AlZnMgCuScZr alloy at temperature...
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Development of Dataster Tool
Vlach, Martin ; Holík, Lukáš (referee) ; Smrčka, Aleš (advisor)
This bachelor thesis deals with expansion of existing web application Dataster in Testos platform. This application serves as a user interface for dbgenx tool from the same platform. The main purpose of Dataster is a user-friendly generation of randomized structured data which are used as a database test content. The first goal of this bachelor thesis was, in particular, to extend dbgenx tool with the possibility of generating test data according to the coverage criteria of combinatorial testing. An existing tool Combine from Testos platform has been selected for this purpose. The other part of the thesis deals with a number of small adjustments and expansion of Dataster web application, for a improvement of usability and overall user-friendliness of this application.
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Třídící systémy pro ovoce a zeleninu
Vlach, Martin
The bachelor thesis, which describes the topic of Sorting systems for fruits and vegetables, is elaborated at the Institute of Horticultural machinery at the Faculty of Horticulture of Mendel University in Brno. The Bachelor thesis deals with sorting systems for fruits and vegetables, their types and importance in sorting groups, focus on usage and strengths. Modern trends in working with fruits and vegetables. The bachelor thesis contains pictures which help with better orientation and the idea of the machine work process.
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Influence of deformation on precipitation processes in commercial Al-based alloys with Sc,Zr-addition
Leibner, Michal ; Vlach, Martin (advisor) ; Cieslar, Miroslav (referee)
1 Abstract: Mechanical and thermal properties of Al-5.4wt.%Zn-3.1wt.%Mg-1.5wt.%Cu (AA- 7075), Al-5.2wt.%Zn-3.0wt.%Mg-1.4wt.%Cu-0.2wt.%Sc-0.1wt.%Zr (AA-7075-ScZr) and Al-2.93wt.%Mg-0.34wt.%Mn-0.33wt.%Si-0.22wt.%Fe-0.19wt.%Cr-0.24wt.%Sc-0.06wt.%Zr (AA-5754-ScZr) alloys in as-cast and cold-rolled states were studied by differential scanning calorimetry and microhardness measurements. The initial values of microhardness reflect an effect of cold-rolling. The Sc,Zr-addition caused a pronounced hardening during annealing above ~ 300 řC. An easier diffusion of Zn, Mg, Cu and Mn atoms along dislocations led to a precipitation of Zn,Mg,Cu-containing and Mn-containing particles at lower temperatures in comparison with the AA-7075(-ScZr) and AA-5754-ScZr alloy in the as-cast state, respectively. The Sc,Zr-addition does not significantly influence precipitation of the particles form the Al-Zn-Mg-Cu system.
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Phase transformation in magnesium MgZnAl-based alloys
Kodetová, Veronika ; Vlach, Martin (advisor)
In the present work, there was analyzed thermal evolution of the phase transformation in the MgZnAl and MgZnAlCa alloys with different concentration of the Zn and Ca. The grains were occupied by the phase with quasicrystaline icosaedral structure in the as-cast alloys and after isochronal annealing up to 240 řC. The thermal measurements revealed two exothermic effects in the MgZnAl alloy and three exothermic effects in the MgZnAlCa alloy during linear heat treatment in the temperature range of 100 - 250 řC. In agreement to the thermal response, two and three stages of electrical resistivity decrease were observed in the same temperature range. The lower thermal changes, absolute resistivity changes and microhardness were observed in the alloy with Ca-addition and lower concentration of Zn.
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Výzkum interakce vodíku s vakacemi, dislokacemi a hranicemi zrn v Ti
Knapp, Jan ; Čížek, Jakub (advisor) ; Vlach, Martin (referee)
This thesis deals with the system of titanium and hydrogen. Interstitial hydrogen alloys and hydrides are subject to intensive investigation, both theoretical and experimental. It has been proved, that absorbed hydrogen lowers the formation energy of defects in metals, and thus works as the so called 'defactant'. Surfactants on the surfaces of liquids lower the surface tension; defactants in solids lower the formation energy of defects. It has also been proved, that titanium absorbs hydrogen readily, when exposed to high temperature, or high pressure (fugacity); while different loading conditions lead to different features of the final sample. Beside ordinary coarse grained titanium, ultra-fine grained titanium shall be studied in present work, due to its high content of defects. Positron Annihilation Life-time Spectroscopy, a non-destructive technique sensitive on open-volume defects, shall be of prime importance in our investigation. We shall further use the X-ray diffraction, Micro-hardness measurements and Differential Scanning Calorimetry together with Thermogravimetry. Lastly, we shall strongly benefit from using existing computational tools like the Vienna ab-initio Simulation Package, or Pos330; a program for positron life--times calculations.
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