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Chemical heat treatment of steel
Pišek, David ; Molliková, Eva (referee) ; Němec, Karel (advisor)
This bachelor thesis deals with methods of chemical and heat treatment of steel. This thesis incorporates basic findings and ways of the performance of the chemical and heat treatment with detailed specialization in cementation and nitration of steels. This study is also focused on property of surface layers and their use. The primary aim of this thesis is to evolve an overview of the most frequent methods of chemical and heat treatment of steel and to evaluate advantages and disadvantages of individual methods for a practical use in industry.
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High-entropy alloys – bulk alloys and surface treatments
Pišek, David ; Šiška, Filip (referee) ; Hadraba, Hynek (advisor)
Master‘s thesis deals with the preparation and evaluation single-phase high-entropy alloy based on cobalt, chromium, iron, nickel and manganese and its variants strengthened by dispersion of oxidic particles. High-entropy alloy was prepared in powder form by mechanical alloying from the equiatomic proportions of atomic powders. Obtained powder was subsequently compacted by spark plasma sintering. By the method of mechanical alloying were successfully prepared single-phase high-entropy alloy and its variant strengthened by dispersion of nanometric yttria oxides. It has been found that the oxide particles present in the microstructure of high-entropy alloy significantly block mobility of grain boundary and dislocation at elevated temperatures. As a result of this behavior were observed doubling of alloy strength and decreasing of creep rate at 800 °C.
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High-entropy alloys – bulk alloys and surface treatments
Pišek, David ; Šiška, Filip (referee) ; Hadraba, Hynek (advisor)
Master‘s thesis deals with the preparation and evaluation single-phase high-entropy alloy based on cobalt, chromium, iron, nickel and manganese and its variants strengthened by dispersion of oxidic particles. High-entropy alloy was prepared in powder form by mechanical alloying from the equiatomic proportions of atomic powders. Obtained powder was subsequently compacted by spark plasma sintering. By the method of mechanical alloying were successfully prepared single-phase high-entropy alloy and its variant strengthened by dispersion of nanometric yttria oxides. It has been found that the oxide particles present in the microstructure of high-entropy alloy significantly block mobility of grain boundary and dislocation at elevated temperatures. As a result of this behavior were observed doubling of alloy strength and decreasing of creep rate at 800 °C.
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Chemical heat treatment of steel
Pišek, David ; Molliková, Eva (referee) ; Němec, Karel (advisor)
This bachelor thesis deals with methods of chemical and heat treatment of steel. This thesis incorporates basic findings and ways of the performance of the chemical and heat treatment with detailed specialization in cementation and nitration of steels. This study is also focused on property of surface layers and their use. The primary aim of this thesis is to evolve an overview of the most frequent methods of chemical and heat treatment of steel and to evaluate advantages and disadvantages of individual methods for a practical use in industry.
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Rating mass concentration of airborne dust in road transport depending on the speed of vehicles
PÍŠEK, David
This thesis focuses on an evaluation of the mass concentration of airborne dust in road transport in relation to the speed of the vehicles. Initially described are airborne dust, its types, fractions and impacts on humans and living environment. Furthermore, the work devotes itself to the measures taken against dustiness, the effects and impacts of transport on living environment and the closely related EURO European emission limits. Part of the work also includes a description of the DustTRAK II 8530 measuring device and individual measurements of dustiness of fraction size 10 m (PM10) during the movement of two vehicles of different weights on selected transport routes. The values measured and their analysis show that the size of the dust matter concentration in the atmosphere is affected by several factors. The main factors are the level and nature of pollution and the type of transport routes, the intensity of traffic, the speed of passing vehicles, the chosen track of passing vehicles in the traffic lane and the distribution of dirt on the road.
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