National Repository of Grey Literature 9 records found  Search took 0.00 seconds. 
Tungsten-steel and tungsten-chromium composites prepared by RF plasma spraying
Matějíček, Jiří ; Klečka, Jakub ; Čížek, Jan ; Veverka, Jakub ; Vilémová, Monika ; Chráska, Tomáš ; Ganesh, V.
For future fusion reactors, materials able to withstand harsh environments are needed. In particular, this concerns the plasma-facing components which are foreseen to consist of tungsten based plasma-facing armor and structural and cooling part made of steel. Currently, joining of these materials presents a significant challenge. The stress concentration at their interface, which arises due to thermal exposure and the difference in thermal and mechanical properties, can be reduced by composite/graded interlayers. Plasma spraying is among the prospective technologies for their preparation. In this work, tungsten-steel and tungsten-chromium composites were prepared by radio-frequency inductively coupled plasma (RF-ICP) spraying. Initial optimization of the spraying process for pure materials as well as their mixtures was carried out. Basic characterization of the layers for their structure, porosity and composition is presented.
Thin nitride layers as permeation barriers
Veverka, Jakub ; Matějíček, Jiří ; Lukáč, František ; Pospíšil, D. ; Cvrček, L. ; Nemanič, V.
Permeation barriers represent one of the crucial fields in materials development for thermonuclear fusion. Primary objective of the barriers is to suppress the permeation of hydrogen isotopes (mainly tritium) from future thermonuclear fusion facilities. Secondary objective is to reduce their retention in structural materials. Expected reactor conditions put high demands on the material, as well as on the final barrier quality. Key properties are tritium permeation reduction, absence of defects (especially cracks), high-temperature stability and corrossion resistance, and compatibility with structural materials (mostly ferritic-martensitic steels). Thin nitride layers, identified as promising permeation barriers, were prepared by diffusion-based nitridation and physical vapour deposition (PVD), and characterized.
Powder feeding analysis in RF-ICP
Zlatník, Rostislav ; Veverka, Jakub (referee) ; Čížek, Jan (advisor)
The work is focused on the problematics of inductively coupled plasma, which is used for deposition of layers. We focused on two goals in the work. The first one focused on powder feeder, which is working on the vibration principle and is used in an apparatus that is using inductively coupled plasma. The aim is to determine its properties, dependence on different input parameters and working conditions. Is important to verify the suitability of its use for this kind of application. The assumption was to find the ideal configuration of the feeder for the given powder. After an overall assessment of the feeder properties, it was recognized as inappropriate for this application. The second goal is to spray tungsten layers with three different tungsten powders. Layers made with an inductively coupled plasma technology delivers promising results, but this issue needs to be intensively addressed in the future.
Alternative Methods of Permeation Barriers Preparation
Veverka, Jakub ; Matějíček, Jiří
Permeation barriers represent one of the crucial fields in materials development for thermonuclear fusion. Primary objective of the barriers is to suppress the permeation of hydrogen isotopes (mainly tritium) from future thermonuclear fusion facilities. Secondary objective is to reduce their retention in structural materials. Expected reactor conditions put high demands on the material, as well as on the final barrier quality. Key properties are tritium permeation reduction, absence of defects (especially cracks), high-temperature stability and corrossion resistance, and compatibility with structural materials (mostly ferritic-martensitic steels). Thin nitride layers, identified as promising permeation barriers, were prepared by diffusion-based nitridation and physical vapour deposition (PVD), and characterized.
Disintegration of sludge thickened by flotation
Veverka, Jakub ; Jecha, David (referee) ; Houdková, Lucie (advisor)
The main topic of this thesis is a research of influence of disintegration of sewage sludge on the production of biogas during the process of anaerobic fermentation. The theoretical part deals with issues and specific methods used during the process of waste water cleaning, furthermore it contains simplified description of waste water treatment plants and particular devices. The number of ways of processing sewage sludge and its potential utilization id also discussed. Following parts of the thesis analyze in detail my own process of anaerobic fermentation including important factors influencing this process. Comparison of aerobic and anaerobic fermentation and ecological perspective on the issue are included in this part. Another important part of the thesis deals with disintegration and description of the disintegration methods and devices. The fundamental part implies the analysis of the executed experiments. Experiments analyze the growth of biogas during anaerobic fermentation depending on the disintegration of sewage sludge. After that the evaluation of the experiments is stated together with economical calculations of the disintegration process executed in laboratory conditions.
Business Plan for New Enterprise
Nováková, Ivana ; Veverka, Jakub (referee) ; Khateb, Fabian (advisor)
The Master‘s thesis deals with processing of business plan of Florist's in Brankovice. The theoretical part describes the theoretical background needed to develop the business plan. The practical part includes marketing research, analysis of the interal and external enviroment and draft of the business plan.
Domestic heat pump
Veverka, Jakub ; Joch, Lukáš (referee) ; Pospíšil, Jiří (advisor)
The aim of the Bachelor's thesis is the ,,Heat pumps and house heating " . The thesis is divided into four main parts. The first part briefly describes the principle of operation and the types of heat pumps (The variants are water to water, air to water, earth to water), including the advantages and disadvantages of their use. Heat pumps are effective solutions to home and hot water heating. The part describes the heat transfer between the condenser and the heating pipes. The second part includes a proposal for using the specific heat pump, a brief description of the selected object and calculate the heat loss. The third part pays attention to calculating the energy performance of buildings. Economic evaluation of the selected system and financial returns are contained in the fourth part of this work.
Letecká doprava v evropském prostoru a její perspektivy
Veverka, Jakub ; Kašpar, Václav (advisor) ; Vošta, Milan (referee)
Práce se zabývá leteckou dopravou v evropském prostoru a jejími perspektivami. Práce je rozčleněna do pěti kapitol, které analyzují hlavní mezníky v historii letecké dopravy v Evropě, současnou leteckou dopravu ve vzdušném prostoru Evropy, spolupráci mezi leteckými dopravci, pozici dvou největších výrobců letadel tj. Airbus Industry a Boeing, situaci menších výrobců a ruských producentů, fenomén ekonomického rozmachu nízkonákladových leteckých společností a dopady na velké letecké dopravce.
The perspectives of air transport between EU member states and North America
Veverka, Jakub ; Kašpar, Václav (advisor) ; Vošta, Milan (referee)
The final thesis analyzes the actual situation of air transport in North America and the EU. New Open skies treaty signed by EU and USA (also EU and Canada) is the objective of the final thesis. An other goal is its influence on transatlantic flights. Moreover the final thesis treats of the allocation of the airport's slots and the actual safety situation as well. Finally there is a small part about alternative jet fuels and the perspectives of air freight transport.

See also: similar author names
2 Veverka, Jan
1 Veverka, Jaromír
1 Veverka, Jaroslav
2 Veverka, Jiří
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