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Computer modeling of high-entropy alloys
Papež, Pavel ; Jan, Vít (referee) ; Zelený, Martin (advisor)
This Master’s thesis is focused on theoretical study of the high entropy alloy CoCrNi using ab initio calculations. The focus was on the effect of short range order on the relative stability of FCC and HCP structures and the value of stacking fault energy.The results show increase of stability in both types of structures wtih decreasing number of Cr-Cr nearest neighbours. The effect of the number of Cr-Cr nearest neighbours on the stacking fault energy previously shown in literature was not observed. However the strong dependency was found on the change of short range order caused by the shift of (1 1 1) planes after the transformation from the FCC to HCP structure. The effect of interstitial atoms C a N was also studied. Both these interstitials stabilise FCC structure and thus cause the increase of stacking fault energy. Both interstitials prefer octahedral positions with higher amount of Cr in their nearest neighbour shell.
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Correlation of the Small punch test parameters with conventional mechanical properties of nonferous alloys
Papež, Pavel ; Šebek, František (referee) ; Zapletal, Josef (advisor)
Bachelor’s thesis is focused on description of the penetration techniques called Small punch test, it‘s advantages and disadvantages, sample removal techniques, different types of construction and mechanisms appearing in it's process. Further the thesis describes different methods of correlation of acquired parameters to classical testing methods, with focus on basic mechanical properties, fractographic and creep properties. At the end is an experimental part on aluminium alloy EN AW 2024. The experiment consisted of correlation to tensile test and shows asymetry of mechanical properties in different directions of material.
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Computer modeling of high-entropy alloys
Papež, Pavel ; Jan, Vít (referee) ; Zelený, Martin (advisor)
This Master’s thesis is focused on theoretical study of the high entropy alloy CoCrNi using ab initio calculations. The focus was on the effect of short range order on the relative stability of FCC and HCP structures and the value of stacking fault energy.The results show increase of stability in both types of structures wtih decreasing number of Cr-Cr nearest neighbours. The effect of the number of Cr-Cr nearest neighbours on the stacking fault energy previously shown in literature was not observed. However the strong dependency was found on the change of short range order caused by the shift of (1 1 1) planes after the transformation from the FCC to HCP structure. The effect of interstitial atoms C a N was also studied. Both these interstitials stabilise FCC structure and thus cause the increase of stacking fault energy. Both interstitials prefer octahedral positions with higher amount of Cr in their nearest neighbour shell.
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Correlation of the Small punch test parameters with conventional mechanical properties of nonferous alloys
Papež, Pavel ; Šebek, František (referee) ; Zapletal, Josef (advisor)
Bachelor’s thesis is focused on description of the penetration techniques called Small punch test, it‘s advantages and disadvantages, sample removal techniques, different types of construction and mechanisms appearing in it's process. Further the thesis describes different methods of correlation of acquired parameters to classical testing methods, with focus on basic mechanical properties, fractographic and creep properties. At the end is an experimental part on aluminium alloy EN AW 2024. The experiment consisted of correlation to tensile test and shows asymetry of mechanical properties in different directions of material.
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The significance of relationship between mesomorphy component and neuromotor development at football players population U12 selected from the highest czech league
Papež, Pavel ; Musálek, Martin (advisor) ; Kokštejn, Jakub (referee)
Title: The significance of relation-ship between mesomorphy component and neuromotor development at football players population U12 selected from the highest czech league. Objectives: The aim of this thesis is to determine the link between the level of mesomorphy (one of the components of somatotype) and neuromotor age at the first league football players U12 from FK Dukla Praha and Bohemians 1905. Methods: The main research method was the method of observation. The research sample contained a total of 41 footballers. For determining the somatotype we used the methodology from Heath - Carter 1967. The degree of neuromotor development was assessed by Bruininks Oseretsky Test of Motor Proficiency (BOT - 2). The estimation of the biological age was calculated from the proportional, growth and weight age and for the calculation of the decimal age we used the equation from Šelingerová (1992). In order to analyse the data we used the basic descriptive statistics, the two-sample T - test, the analysis of variance, the correlation and the linear regression. Results: The results revealed that there is no significant relationship r2 = 0,04 % between the level of mesomorphy (rated by Heath - Carter) and the performance in neuromotoric. Further, subsequent analysis of the separate muscle component in...
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