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An investigation of friction and lubrication of coated hip joint replacement
Balcárek, Ondřej ; Horák, Zdeněk (referee) ; Nečas, David (advisor)
The thesis focused on studying the effects of a new hydrogel coating and material combinations on the coefficient of friction and formation of lubricating film in the conformal contact of hip joint replacement. Experiments were conducted using a ball-on-cup configuration with a hip pendulum simulator. The formation of the lubricating film was observed using fluorescence microscopy. The results showed that the application of the coating did not have a clear impact on the coefficient of friction. However, for pairs with a coated cup, there was a reduction in CoF by approximately 20%. Generally, lower friction was observed when using a ceramic joint head. Surprisingly, even more interesting results were obtained in the lubrication analysis, where the use of metal heads led to a reduction in the thickness of the lubricating layer. Ceramic pairs exhibited very stable behavior. In addition to friction and lubrication, the topography of the implants was further evaluated, and their wettability was analysed. Although the polymer coating was expected to be highly hydrophilic, the surface properties were only slightly influenced, which partly explains why there was no significant improvement in the tribological behavior of the replacement. As the coating applied is already patented and its effectiveness in reducing wear has been clearly demonstrated, it is appropriate to investigate this issue further, with more attention being paid to long-term experiments. Based on the obtained data, it appears that the short-term benefits of the coating are practically negligible. However, it is important to highlight that, except for minor exceptions, the application of the coating did not lead to a deterioration of properties, which is a significant outcome of this work.
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Machinable bioceramic foams prepared by gelcasting method
Šťastný, Přemysl ; Částková, Klára (referee) ; Trunec, Martin (advisor)
Diploma thesis is focused on development of method for preparation individualized bioscaffolds prepared by milling of HA foam prepared by gel casting method and consolidated via epoxy curing reaction. Diploma thesis continues in bachelor thesis Modern processing methods of porous bioceramics. Literature search is filled in the newest knowledge from the field of bioactivity enhancement of scaffolds. Experimental part of diploma thesis described development of system for individualized scaffold manufacturing from HA suspension preparation, preparation of ceramic blocks used as material for machining to final blocks machining. Pressure strength of foam were evaluated, too. Chosen samples were coated with calcium polyphosphate coating for biological response enhancement. Coated samples were given for in-vivo test to partner university in Beijing under the terms of project FP7-NMP-2013-EU-China: "Bioscaffolds"
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New generations of PVD coatings
Kantar, Filip ; Kolář, Ladislav (referee) ; Jaroš, Aleš (advisor)
Bachelor thesis deals with methods of coating, cutting tools and a new generation of coatings. In the first part are listed and described basic coating methods. The next part is aimed on coating of PVD methods. In the third part are listed basic tool materials and their characteristics. The last part is focused on new generation of coatings, their application, properties and structures.
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Analysis of the surface after laser cutting
Narovec, David ; Sedlák, Josef (referee) ; Osička, Karel (advisor)
This diploma thesis discusses laser cutting and the consecutive surface treatment of cut parts. The theory of laser cutting is described in the first part of this thesis, including laser history and the laser emergence principle. Cut parameters and the influence of the laser cutting on the material are described later on. The next part describes the laser cutting technological possibilities and other laser technology utilization options are outlined. In the last theory part, metal surface treatment used in the experiment is covered. Coating thickness is evaluated in the practical part of this thesis, as well as roughness, microhardness, chemical microanalysis and metalography. The evaluation of the results achieved, and optimal surface treatment execution suggestions are addressed in the last part of this thesis.
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Modern cutting cemented carbide tools
Vopařil, Josef ; Humár, Anton (referee) ; Píška, Miroslav (advisor)
This thesis is focused on cutting tools made of cemented carbides. It contains analysis of cemented carbides for uncoated and coated cutting tools. It contains examples of modern tools for turning, milling and drilling. Practical part of this thesis evaluates and compares cutting properties of two types of spiral drills.
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Influence of coatings on durability of cutting inserts during longitudinal turning
Balíček, Martin ; Sámelová, Vendula (referee) ; Jaroš, Aleš (advisor)
This thesis deals with the influence of deposited coatings for durability and tool wear during longitudinal turning of steel CSN 41 1600 (E335) and influence of wear and surface quality. The theoretical part is focused on characteristics of turning technology, application, manufacturing and methods of coating cemented carbide and tool wear. The experimental part of the thesis includes the evaluation of the measured values, a description of the material, used tools and machine tool. The values measured in the experiment imply that the most suitable of the tested tool inserts is WNMG 3-1-NF with applied coating TiAlN + TiN. Surface quality decreases with increasing wear of the tool.
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Reduction of Contact Pairs Friction Losses
Novotný, Marek ; Raffai, Peter (referee) ; Maršálek, Ondřej (advisor)
This bachelor thesis deals with the topic of mechanical efficiency of contact pairs in the crankshaft of the combustion engine. The introductory section focuses on the efficiency of the combustion engine as a whole. In addition, it describes the areas where mechanical losses primarily occur. The following chapters describe mechanism of friction losses, the main factors affecting their amount and the most modern ways to increase mechanical efficiency. In the closing chapter, some basic computing relations, describing the size of mechanical losses are listed. The aim of this thesis is to acquaint the reader with the importance of mechanical efficiency in the area of combustion engines.
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Technological applications of cemented carbide tools
Brlica, Vlastimil ; Humár, Anton (referee) ; Prokop, Jaroslav (advisor)
The fully fashioned bachelor’s thesis within the frame of the bachelor‘s study B2339-00 at the Fakulty of mechanical engineering deals with subject cemented carbide tools. General infomation is characterized by literary production; e.g. division, characteristics and manufacturing. The particular examples of cutting conditions are worked up in the second part of this study followed by calculation of economic aspects in the proces of tooling. The information about materials, cutting conditions and prices of exchange cutter bit from cemented carbide are drawn from catalogues of Sandvik – Coromant company.
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