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Use of laser-TIG hybrid technology for welding of different materials used in power engineering
Žák, Tomáš ; Beran, David (referee) ; Mrňa, Libor (advisor)
Thesis is focused on analyzing the influence of preheating process parameters using electric arc from TIG torch during laser welding on weld properties of stainless steel and carbon steel with higher strength. In this thesis experiment was done in which metal sheets 3 mm thick from X12Cr13 and S355 steels were welded. Welding was done first with using only laser, then laser with TIG preheating and lastly laser with preheated material by induction heater. When TIG preheating was used than set welding current was changed on the power source. The welds were subsequently evaluated based on macrostructure, microstructure and Vickers hardness test.
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Urban community garden "Smetanka" in years 2014-2017: reasons to gardening, a conflict and the over
Beran, David ; Novák, Arnošt (advisor) ; Čada, Karel (referee)
This thesis is based upon the phenomenon known as urban community gardening, and examines it with regards to conflicts within an intended environment. The theoretical section is based on a school of thought that holds nature as something that exists in both science and humanities, and which can be observed within the social world. As opposed to nature and society being divided, this part will address the term 'socionature', which comprises a current post-anthropocentric stream of humanities and social sciences. Essentially it stays on the theory of conflicts. The research posits answers to the question of how gardeners justify and reasonably support their activities at an urban community garden called "Smetanka garden" in Vinohrady, Prague. Two of the outcomes were: the cultivation of strong neighbourly relations; and encouragement of recreational family outings. The Smetanka garden was closed in 2017. The thesis sees the conflict that occurred around the closure as a socionatural conflict. One question is, what were the arguments for closing the garden? The main argument stated that the land should be used for construction of sports facilities to serve the schools nearby. Furthermore, the community garden was only meant to be temporarily from the beginning. Proponents maintained that the garden...
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Use of laser-TIG hybrid technology for welding of different materials used in power engineering
Žák, Tomáš ; Beran, David (referee) ; Mrňa, Libor (advisor)
Thesis is focused on analyzing the influence of preheating process parameters using electric arc from TIG torch during laser welding on weld properties of stainless steel and carbon steel with higher strength. In this thesis experiment was done in which metal sheets 3 mm thick from X12Cr13 and S355 steels were welded. Welding was done first with using only laser, then laser with TIG preheating and lastly laser with preheated material by induction heater. When TIG preheating was used than set welding current was changed on the power source. The welds were subsequently evaluated based on macrostructure, microstructure and Vickers hardness test.
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