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High-speed shaft production design
Polesný, Pavel ; Jaroš, Aleš (referee) ; Kalivoda, Milan (advisor)
In the bachelor's thesis, a production process of the crankshaft of a single-cylinder two-stroke engine is designed. The flywheel has a diameter of 20.5 mm, the crank pin has a diameter 9 g6, the connecting rod pin has a diameter 4 g6, and the total length is 63.5 mm. Due to the production batch of 1000 pieces, the machining method was selected. The crankshaft will be produced as a monolith. Then the grooves at the ends of the ground surfaces 9 g6 and 4 g6 were addressed. Due to the wall thickness of 1.25 mm, the surfaces will be without grooves, and a radius or chamfer will be in the corners. The axial bearing and the connecting rod have an internal chamfer of 0.7x45°, thus grooves are unnecessary. The chosen material is 15.142 steel, tempered to a lower strength, supplied in 25x3000 mm bars by ZJP, s.r.o. The semifinished part will be manufactured on a Swiss-type lathe Manurhin K'MX EVO 732. After nitriding, the part will be ground on a Bernardo URS 500 N grinder. For the machining on the EVO 732, OPTIMA EXTREMECUT 46 mineral oil was chosen, and for grinding, a 2% concentration emulsion mixed from BITOL M petroleum emulsion oil was selected. Then the technological process was developed, and operational instructions were created. Calculations determined that 26 bars are needed for the production of the specified series. The entire series production will take just under 4 shifts.
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Analysis of heat treatment effect on dimension shift
Kunkela, Ondřej ; Jaroš, Aleš (referee) ; Kolář, Ladislav (advisor)
This bachelor thesis focuses on chemical-heat steel processing, mainly to the size change caused by the process itself. To look into the problem closely some samples from various materials and of various size have been made. The samples were measured before and after the ionic nitridation. Likewise the samples, the real peaces were measured, some of them were ionic nitridated and some were cemented. The real pieces were made from the same material but they differed in size and shape. Subsequently, all the figures were processed and assessed.
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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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Deposition of Ga and GaN ultrathin layers on graphene substrate
Dvořák, Martin ; Nebojsa, Alois (referee) ; Mach, Jindřich (advisor)
This diploma thesis deals with preparation of graphene samples for depositions of ultrathin layers of gallium and gallium nitride. Graphene substrates were prepared by chemical vapour deposition in home-build high temperature reactor. After graphene transfer to silicon wafers, a series of chemical and thermal treatments were performed. Obtained samples were suitable for the study of growth of ultrathin layers of Ga and GaN. The growth of Ga and GaN was realized in ultra high vacuum conditions. Molecular beam epitaxy technique was used for gallium depositions together with ion source for nitridation. Obtained ultrathin layers were studied with X-ray photoelectron spectroscopy, atomic force microscopy and with scanning electron microscopy.
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The deposition of Ga and GaN nanostructures on silicon and graphene substrate
Mareš, Petr ; Hospodková,, Alice (referee) ; Mach, Jindřich (advisor)
Presented thesis is focused on the study of properties of Ga and GaN nanostructures on graphene. In the theoretical part of the thesis a problematics of graphene and GaN fabrication is discussed with a focus on the relation of Ga and GaN to graphene. The experimental part of the thesis deals with the depositions of Ga on transferred CVD-graphene on SiO2. The samples are analyzed by various methods (XPS, AFM, SEM, Raman spectroscopy, EDX). The properties of Ga on graphene are discussed with a focus on the surface enhanced Raman scattering effect. Furthermore, a deposition of Ga on exfoliated graphene and on graphene on a copper foil is described. GaN is fabricated by nitridation of the Ga structures on graphene. This process is illustrated by the XPS measurements of a distinct Ga peak and the graphene valence band during the process of nitridation.
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The influence of coatings on fracture behaviour of ledeburitic steel
Šafář, Martin ; Jurči,, Peter (referee) ; Hadraba, Hynek (advisor)
This work deals with tool steel Vanadis 6. It describes the preparation of samples for the three-point bending test, with which it examines the influence of surface roughness, the effect of nitriding, coating and duplex coatings on fracture behaviour of the steel. First, it examines bending strength and the total energy required to work of fracture. The work also includes mapping and measurement of surface roughness on different layers. This measurement is performed on a confocal microscope.
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Deposition of GaN nano structures on Si(111) 7x7
Šťastný, Jakub ; Horák, Michal (referee) ; Mach, Jindřich (advisor)
The thesis is focused on the study of growth of 2D GaN nanocrystals on Si(111) 7x7. In the theoretical part of this thesis the properties of 3D and 2D GaN, main methods used for growth of GaN and 2D GaN and applications of GaN are described. The experimental part of this thesis describes in detail the method of low temperature droplet epitaxy with assistance of ions, which was used for series of deposition of 2D GaN under different angles of ion beam. The deposition was done in the complex UHV system in the ÚFI VUT labs in Brno. The nanocrystals were analysed by SEM and AFM.
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Analysis of heat treatment effect on dimension shift
Kunkela, Ondřej ; Jaroš, Aleš (referee) ; Kolář, Ladislav (advisor)
This bachelor thesis focuses on chemical-heat steel processing, mainly to the size change caused by the process itself. To look into the problem closely some samples from various materials and of various size have been made. The samples were measured before and after the ionic nitridation. Likewise the samples, the real peaces were measured, some of them were ionic nitridated and some were cemented. The real pieces were made from the same material but they differed in size and shape. Subsequently, all the figures were processed and assessed.
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The deposition of Ga and GaN nanostructures on silicon and graphene substrate
Mareš, Petr ; Hospodková,, Alice (referee) ; Mach, Jindřich (advisor)
Presented thesis is focused on the study of properties of Ga and GaN nanostructures on graphene. In the theoretical part of the thesis a problematics of graphene and GaN fabrication is discussed with a focus on the relation of Ga and GaN to graphene. The experimental part of the thesis deals with the depositions of Ga on transferred CVD-graphene on SiO2. The samples are analyzed by various methods (XPS, AFM, SEM, Raman spectroscopy, EDX). The properties of Ga on graphene are discussed with a focus on the surface enhanced Raman scattering effect. Furthermore, a deposition of Ga on exfoliated graphene and on graphene on a copper foil is described. GaN is fabricated by nitridation of the Ga structures on graphene. This process is illustrated by the XPS measurements of a distinct Ga peak and the graphene valence band during the process of nitridation.
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Deposition of Ga and GaN ultrathin layers on graphene substrate
Dvořák, Martin ; Nebojsa, Alois (referee) ; Mach, Jindřich (advisor)
This diploma thesis deals with preparation of graphene samples for depositions of ultrathin layers of gallium and gallium nitride. Graphene substrates were prepared by chemical vapour deposition in home-build high temperature reactor. After graphene transfer to silicon wafers, a series of chemical and thermal treatments were performed. Obtained samples were suitable for the study of growth of ultrathin layers of Ga and GaN. The growth of Ga and GaN was realized in ultra high vacuum conditions. Molecular beam epitaxy technique was used for gallium depositions together with ion source for nitridation. Obtained ultrathin layers were studied with X-ray photoelectron spectroscopy, atomic force microscopy and with scanning electron microscopy.
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