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Stainless steels for cryogenic applications processed by 3D printing
Grygar, Filip ; Hutař, Pavel (referee) ; Koutný, Daniel (advisor)
This thesis deals with properties of austenitic stainless steel 304L processed by SLM technology and tested at room and cryogenics temperatures. Result is description of mechanical properties and microstructure. First step was to develop processing parameters to achieve porosity of prints fell below 0,01 %. Following tensile test showed higher yield and ultimate tensile strength than conventionally fabricated parts, even at temperature -80 °C, but at cost of reduced ductility. Due to deformation and low temperature austenite transformed into martensite. This transformation also occurred in Charpy toughness test, that resulted in ductile to brittle behaviour.
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Experimental comparison of recycled and non-recycled filament of ABS plastic
Grygar, Filip ; Krčma, Martin (referee) ; Koutecký, Tomáš (advisor)
Plastic waste which arises from 3D print could be recycled. One of the most used materials is ABS with which this degree work deals. During recycling of ABS mechanical qualities rapidly deteriorate which is compensated by adding non-recycled ABS. This degree work dealt with a ratio of 25% of recycled to 75% of non-recycled material which is a ratio not have been tested so far, and most likely represents a boundary ratio when recycling still makes sense. Unfortunately, it was not possible to extrude from a recycled material a filament of high-quality enough which could be used for problem-free print. It was influenced by non-homogeneity of crushed components and the construction of an extruder. For improving the characteristics a more complex extruder would be needed, with a bigger screw diameter or with two screws, and also a cooling system with more zones. Professional grinders with screens would have to be used for improving homogeneity of the material. The melt flow index of the liquid alloy and the testing of the filament itself showed that this way is practicable and such a recycling is realistic.
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Stainless steels for cryogenic applications processed by 3D printing
Grygar, Filip ; Hutař, Pavel (referee) ; Koutný, Daniel (advisor)
This thesis deals with properties of austenitic stainless steel 304L processed by SLM technology and tested at room and cryogenics temperatures. Result is description of mechanical properties and microstructure. First step was to develop processing parameters to achieve porosity of prints fell below 0,01 %. Following tensile test showed higher yield and ultimate tensile strength than conventionally fabricated parts, even at temperature -80 °C, but at cost of reduced ductility. Due to deformation and low temperature austenite transformed into martensite. This transformation also occurred in Charpy toughness test, that resulted in ductile to brittle behaviour.
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Experimental comparison of recycled and non-recycled filament of ABS plastic
Grygar, Filip ; Krčma, Martin (referee) ; Koutecký, Tomáš (advisor)
Plastic waste which arises from 3D print could be recycled. One of the most used materials is ABS with which this degree work deals. During recycling of ABS mechanical qualities rapidly deteriorate which is compensated by adding non-recycled ABS. This degree work dealt with a ratio of 25% of recycled to 75% of non-recycled material which is a ratio not have been tested so far, and most likely represents a boundary ratio when recycling still makes sense. Unfortunately, it was not possible to extrude from a recycled material a filament of high-quality enough which could be used for problem-free print. It was influenced by non-homogeneity of crushed components and the construction of an extruder. For improving the characteristics a more complex extruder would be needed, with a bigger screw diameter or with two screws, and also a cooling system with more zones. Professional grinders with screens would have to be used for improving homogeneity of the material. The melt flow index of the liquid alloy and the testing of the filament itself showed that this way is practicable and such a recycling is realistic.
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Hermeneutic Phenomenology and Quantum Complementarity in the Philosophy of Science
Grygar, Filip ; Michálek, Jiří (advisor) ; Krtouš, Pavel (referee) ; Kvasz, Ladislav (referee)
Facultyof Scienceof the CharlesUniversityin Prague Mgr.Filip Grygar Hermeneutic Phenomenology and Quantum Gomplementarity in the Philosophy of Science PhD ThesisSummary 2008 An ambition of the presenteddissertation is an interdisciplinary treatise of phenomenology and quantum theory; therefore an attemptto connect two seemingly independently forming disciplines that have been holding a leading position in philosophical and scientificthinking since the beginningof the 20th century. Specifically, I lay stresson Heidegger's hermeneuticphenomenology on one hand and on Bohr's philosophy and the frame of complementariý on the otherhand. I outlined, in Chapter d how a monolithlc modern scientific view of the world and mathematizationof naturewas developed.Concurrently to this topic, I showed two for,med possibilities of thinking - meditative thinking and calculative thinking that is linked to Heidegger's analyses of essence of technology qua Gestel/. Since the appearanceof Husserl and Heidegger's phenomenology,modern objectivist scientific notions and the subject-object paradigm oťcalculative thinking has been called in question.Modern thinking and its world view turned out to be insufficient and its thinking showed to be single-sided in its description of nature (especially in its description of subatomic...
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Budoucnost biopaliv v evropském palivoenergetickém řetězci
Grygar, Filip ; Slavíková, Lenka (advisor) ; Czesaný, Slavoj (referee)
Tato práce se zabývá zaváděním biosložek do pohonných hmot v Evropské Unii a dopadem této činnosti na životní prostředí a ekonomiku států. Jedná se o snahu redukovat závislost na ropě, jejíž zásoby se dle odborníků snižují a taktéž o snahu omezit produkci emisí z automobilové dopravy, zejména skleníkových plynů, jež se nemalou měrou podílejí na klimatických změnách. Nárůst spotřeby ropy a produkce emisí během posledního století je vysoký a způsoben především zvyšujícím se počtem automobilů, který je ovlivněn mimo jiné, vyšší životní úrovní obyvatel Evropy. Cílem této práce je srovnat mezi sebou ideu Evropské unie o přechodu na biopaliva a zprávy světových organizací, které tento postup kritizují. Dalším cílem práce bude snaha zjistit, zda vůbec, a za jakých podmínek, a v jakém množství je zavádění biosložek výhodné a ekonomicky efektivní, vzhledem k nákladům na výrobu směsného paliva a nákladům na zavedení opatření včetně dopadu na státní rozpočet.
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