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Strain, stress and strength analysis of the high pressure compound vessel by finite element method
Koutský, Jiří ; Suchánek, Miroslav (referee) ; Vrbka, Jan (advisor)
Strength and strain analysis of high pressure compound vessel, which is used to produce superhard materials (for example synthetic diamond). This work was elaborated to compare the stresses and strains calculated by Prof. Jan Vrbka making use of the FEM program ‘Prokop’17 years ago with those gained with the contemporary FEM Ansys program. The vessel is loaded by internal pressure of size 6 GPa. The elastic-plastic material be-haviour is taken into account. Real value of friction between rings and non-uniform temperature field is included into the calculation. The process of assembling the compound vessel is simulated step by step.
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Superhard cutting materials and theirs effective use
Grausgruber, Jiří ; Prokop, Jaroslav (referee) ; Humár, Anton (advisor)
n the first part of this diploma thesis there are described basic findings about superhard cutting materials (sorts, notation, structure, physical-mechanical properties, usage, production) and evaluates this tool of material from the aspect of cutting ability. The second part focused on complex data processing about assortment of superhard cutting materials of significant tools materials producers and comparison of work conditions (kind of machined ma-terials, cutting conditions), which are recommend for effective turning applica-tions by producers.
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Carbon Based Materials
Hrazdíra, Matěj ; Čelko, Ladislav (referee) ; Klakurková, Lenka (advisor)
The proposed bachelor thesis deals with carbon based materials. First of all, an overview of its allotropic modifications including newly discovered forms, conditions of their existence and also their basic properties is shown. Further the extraction of carbon materials is briefly introduced. In the next chapters, forms of carbon are classified and particularly described individually with respect to manufacturing technologies and further applications. Individual chapters are dedicated to synthetic carbon and graphite, carbon fibers and carbon fiber reinforced composites. Manufacturing processes of synthetic carbon and graphite, involving possible precursors, are described in detail together with their use in various engineering applications. The following part is dedicated to carbon fibers, in particular to the manufacturing process based on the precursor used including surface treatment and sizing. Additionally the use of virgin carbon fibers is also described. The last part is focused on carbon fiber reinforced composites. Firstly possible distributions of carbon fibers in a matrix are described. Then the technology of manufacturing, properties and use of single composites according to the matrix material are expounded.
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Superhard cutting materials
Mlčoch, Petr ; Dvořáček, Jan (referee) ; Humár, Anton (advisor)
This bachelor thesis deals with superhard cutting tool materials, which include diamond and cubic boron nitride. It is divided into three parts. In the first one there is a short summary of cutting tool materials currently used for machining. The second part pursues sorts, production and properties of superhard cutting materials. The last part represents superhard cutting materials in the offer of two important producers of cutting tool materials and two producers of cutting tools.
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Diamond wheels and their use in the stone industry
Skryja, Jan ; Kolář, Ladislav (referee) ; Jaroš, Aleš (advisor)
This bachelor thesis deals with stone sawing during stone processing. It is divided into theoretical and practical parts. In the theoretical part diamond blades, the sawing process and stone extraction are described. The practical part is focused on the wear of circular saws in granite circular sawing. The wear is determined for two diamond cutting blades made by different manufacturers and is determined by the blade weight loss and segments height loss as a function of time. Both measured values show linear dependence. The results are the basis for a future comparison of the two diamond blades on the economic side, which is not the subject of this work.
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Coating methods for cutting tools
Doležal, Jan ; Madaj, Martin (referee) ; Humár, Anton (advisor)
Bachelor work describes methods of coating of cutting tools and their technical characteristics. The work is given below the current product range of manufacturers of coated cemented carbides. At the end of this work is treated the development of coating cutting tools and types of applied coatings.
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Technological challenges in the fabrication of MoS.sub.2./sub./diamond heterostructures
Varga, Marián ; Sojková, M. ; Hrdá, J. ; Hutar, P. ; Parsa Saeb, S. ; Vanko, G. ; Pribusova Slusna, L. ; Ondič, Lukáš ; Fait, Jan ; Kromka, Alexander ; Hulman, M.
Nowadays, 2D materials are one of the most studied classes of materials. In addition to the most famous graphene, progress has been achieved in studying and using fundamental properties of transition metal dichalcogenides (TMD). Complementary, diamond as a representative of 3D materials has gained a reputation as an extremely versatile material due to its extraordinary combination of physical/chemical/electrical/optical properties. Besides these particular forms of 2D and 3D materials, their heterostructures have become very attractive due to new phenomena and functions (bandgap engineering, enhanced charge transport, optical interaction, etc.). However, individual technological procedures are still minimally investigated and described. Here, we will demonstrate a proof-of-concept for the preparation of MoS2/diamond heterostructures, where two different strategies were employed: a) growth of MoS2 layers on diamond films, and b) growth of diamond films on Si/MoS2 substrates.
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Effect of the substrate crystalline orientation on the surface morphology and boron incorporation into epitaxial diamond layers
Voves, J. ; Pošta, A. ; Davydova, Marina ; Laposa, A. ; Povolný, V. ; Hazdra, P. ; Lambert, Nicolas ; Sedláková, Silvia ; Mortet, Vincent
Epitaxial growth of diamond is critically important for the fabrication of diamond-based electronic devices. The emerging study of the epitaxial diamond growth on the (113) vicinal surfaces evidences highly needed high growth rates and low structural defects concentrations with both p- and n-type doping. In this work, we compare the morphology and dopant concentration incorporation of heavily boron-doped (113) epitaxial diamond layers with conventionally studied (100) and (111) epitaxial layers. Epitaxial layers were grown using resonance cavity Microwave Plasma Enhanced Chemical Vapor Deposition (MWPECVD) system. The surface morphology of epitaxial layers was studied by optical microscopy and atomic force microscopy, whereas the boron incorporation homogeneity was determined by Raman spectroscopy mapping.
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Spectroscopy of semiconductors with ultra-high time resolution
Hanák, Martin ; Trojánek, František (advisor) ; Kozák, Martin (referee)
This thesis is aimed at building and optimization of a new experiment setup for measuring time-resolved transmittance using a pump-probe method. Test measurements were then conducted on a sample of SiV centers in diamond. The theoretical part contains a general description of luminescence of color centers. It then specifically focuses on SiV centers in diamond and describes their structure, electronic and spectral properties in detail. The description of our setup and its optimization is given at the beginning of the experimental part. The dependencies of differential transmittance of SiV centers in diamond on excitation intensity and wavelength were measured and the lifetime of SiV centers was then determined from our measurement results. 1
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