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Study of mechanical properties and microstructure development of fine-grained Cu and Cu alloy polycrystals
Srba, Ondřej ; Janeček, Miloš (advisor)
The objective of the thesis is the study of mechanical properties, microstructure development and corrosion resistance of technical purity copper and Cu-0.18 wt.% Zr polycrystals prepared by ECAP. The tensile tests showed that the characteristic stresses 0,2 and max increase with increasing strain imposed by ECAP. The improvement of mechanical properties is compensated by the drop of ductility in the deformed state. The microstructure after 8 passes of ECAP is almost homogeneous consisting of equiaxed grains of the average size of 200 nm. The severe plastic deformation resulted in the grain size reduction of the factor of 1000. The specimen after 8 passes contains almost 50% of high angle grain boundaries. From the thermodynamic viewpoint the deformation did not change significantly the corrosion properties. However, the corrosion in the deformed material is slower and much more homogeneous.
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Effect of molybdenum content on phase transformations in binary Ti-Mo alloys
Valešová, Veronika ; Stráský, Josef (advisor) ; Janeček, Miloš (referee)
Title: Effect of molybdenum content on phase transformations in binary Ti-Mo alloys Author: Veronika Valešová Department: Department of Physics of Materials Supervisor: PhDr. RNDr. Josef Stráský, Ph.D., Department of Physics of Mate- rials Abstract: β titanium alloys are highly appreciated group of structural materials. They provide an extraordinary combination of strength, toughness and fatigue resistance. These alloys are used predominantly in aerospace sector, chemical industry and medical engineering. We have studied three binary titanium alloys: Ti-12Mo, Ti-15Mo and Ti-18Mo (wt %). Apart from low temperature hexagonal close packed α phase and high temperature base centered cubic β phase, a metastable ω phase can be also found in this type of alloys. The ω phase is created in a diffusionless process by shifting the planes in the β phase and affects both mechanical properties and the α phase precipitation. We have examined the phase transformations occurring in the studied alloys using both in-situ and ex-situ methods. Resistometry, dilatometry and differential scanning calorimetry were used as the indirect in-situ methods. For the ex-situ methods, scanning electron microscopy and microhardness measurement were used. Complex characterization of β metastable titanium alloys showed the formation of the...
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Technological stage of the rough superstructure of the Jaroslavice mill
Janeček, Milan ; Bříza, Lukáš (referee) ; Kantová, Radka (advisor)
This bachelor's thesis deals with the design and technological solution for the implementation of the rough superstructure of the press in Jaroslavice. The con-tent of the work is an accompanying report and summary technical report of the building, the construction situation and the solution of relations of wider trans-port routes, technological regulations for the implementation of ceramic structu-res and for the implementation of wooden ceiling construction, machine design, site equipment solutions, safety and health solutions construction sites and in-spection and test plans for the execution of ceramic structures and for the executi-on of wooden ceiling structures.
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Marketing Communication
Janeček, Michael ; Leitlová, Veronika (referee) ; Schüller, David (advisor)
The bachelor´s thesis focuses on a marketing communication of the M&M finance company s. r. o. and it is divided into the theoretical and practical part. The theoretical part is based on specialized literature and clarifies the terms of marketing communication. In the practical part there are an analysis of the company and own survey. It leads to suggestions for improvement marketing communication.
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Microstructure of commercially pure titanium after cryogenic milling and spark Plasma sintering
Kozlík, J. ; Harcuba, P. ; Stráský, J. ; Chráska, Tomáš ; Janeček, M.
Commercially pure titanium was prepared by advanced powder metallurgy methods with the aim to produce the ultra-fine grained material. Cryogenic attritor milling was used as a first step to refine the microstructure at liquid argon temperatures to suppress recovery and dynamic recrystallization. Spark plasma sintering was subsequently employed to produce bulk material, exploiting its ability to achieve fully dense structure in short time and thus to reduce the grain growth. In order to understand the undergoing microstructural changes during the process, detailed investigation was performed after each preparation step. Powder morphology was changed significantly after milling, while particle fragmentation was only limited. Grain size after sintering was in micrometer scale, relatively independent of sintering conditions.
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Effect of substantial grain refinement on microstructure and mechanical properties of precipitation hardenable magnesium alloys.
Hofman, Daniel ; Minárik, Peter (advisor) ; Janeček, Miloš (referee)
Properties of magnesium alloy WE43 and the effect of substantial grain refinement by ECAP were studied. The compressive strength test revealed a significant increase of yield strength after ECAP, resulting in yield strength of over 400 MPa after 8 ECAP passes. The material remained surprisingly ductile in both compression and tension. Thermal stability of the material was investigated via Vickers hardness test. The ultrafine-grained structure shows good thermal stability up to 300 řC, where the precipitates start to dissolve and grain size starts to increase, resulting in sharp fall of hardness. Annealing of the initial state showed best results for 210 řC where the precipitation hardening led to an increase in hardness up to ∼101 HV.
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Acceleration of calculations in life insurance
Kuzminskaya, Kseniya ; Janeček, Martin (advisor) ; Vitali, Sebastiano (referee)
One of the major issue for life insurance companies is proper and consistent valuation of liabilities. This thesis introduces the standard estimation methods used in practice and discussed the alternative methods, which might help to speed up these calculations. It studies two possible methods of acceleration of calcu- lations in life insurance: analytic function and cluster analysis. The outcome of these work is comparison of discussed methods applied on generated life insur- ance portfolio. All methods were applied on two possible insurance products. Comparison of the results is based on the calculation precision and time needed to process the liabilities of the insurance company's portfolio. 1
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Determining the level of knowledge about proper nutrition at undergraduate students TV and sport
JANEČEK, Marek
The aim of the bachelor thesis is to determine the level of knowledge in the field of nutrition in students of physical education and sport and to determine the importance of knowledge about nutrition as part of the study of physical education and sport. The theoretical part contains information about health, healthy lifestyle, nutrition and nutrition in sport. In more detail, nutrition components such as proteins, fats, sugars, and vitamins are described. Here are also said the most common eating disorders, such as anorexia or bulimia and the most common alternative directions in the nutrition. The practical part deals detection of knowledge of students in the field of physical education and sport. The level of knowledge was detected by the research questionnaire method. Questionnaires were handed over to students during the lessons. The survey was attended by 73 students whose completed questionnaires were evaluated using graphs and tables. On the basic of detected the results, it was created an overview of the level of knowledge about good eating. From results show that a set of questions about the basic knowledge about healthy nutrition is at a very good level. It has also been shown that a group of issues relating to more advanced knowledge about healthy nutrition is at a sufficient level. The bachelor thesis could be further a contribution to creating the content of the subject of nutrition in sport.
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