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Modelling of Phase Composition of Heat Resistant Steels and their Welds
Dvořáček, Ondřej ; Foret, Rudolf (referee) ; Jan, Vít (advisor)
This work deals with the effects of high temperature exposition of low alloyed creep resistant steels on their structural stability and structural stability of their weld joint. The theoretical part of this work gives an overview of creep resistant steels considering their chemical and phase composition and their connection to high temperature mechanical properties. The CALPHAD method is presented as generally accepted approach for equilibrated calculations and Thermo-Calc and DICTRA software packages are introduced as CALPHAD applications. Thermo-Calc software is used for calculation of phase composition of the examined materials and for calculation of the phase diagrams. Software DICTRA is used for simulations of diffusion controlled phase reactions in the analysed weld. Experimentally one weld joint of the steels 15 128 and 15 313 has been studied after four different annealing procedures. The experimental results include chemical profiles across the welds, microhardness profiles and metallographic analysis of significant regions of the welds. These experimental results are compared with the simulation results. The comparison shows a reasonable agreement between experimental and simulation data.
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Querying Spatio-Temporal Data of Moving Objects
Dvořáček, Ondřej ; Kolář, Dušan (referee) ; Zendulka, Jaroslav (advisor)
This master's thesis is devoted to the studies of possibilities, which can be used for representation of moving objects data and for querying such spatio-temporal data. It also shows results of the master's thesis created by Ing. Jaroslav Vališ, that should be used for the solution of this master's thesis. But based on the theoretical grounds defined at the beginning of this work was designed and implemented new database extension for saving and querying spatio-temporal data. Special usage of this extension is demonstrated in an example application. This application uses the database extension for the implementation of its own database functions that are domain specific. At the conclusion, there are presented ways of the farther development of this database extension and the results of this master's thesis are there set into the context of the following project, doctoral thesis "Moving objects database".
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Proposal to drive the fan impeller for ripening chamber
Dvořáček, Ondřej ; Strecker, Zbyněk (referee) ; Dvořáček, Jiří (advisor)
The Bachelor’s thesis deals with a structural design of proposal to drive the fan impeller with vertical axis of rotation for ripening chamber. The introduction gives a brief description of types, parts and operating principles of air conditioned chambers in meat technology. The second part of this work is focused on the design of belt drive, impeller bearing housing and electric motor layout. Thesis contains fundamental engineering calculations for horizontal and vertical axis positions as well as technical drawings.
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Study on stability of bidisperse MR fluid and its magnetorheological effect
Dvořáček, Ondřej ; Mazůrek, Ivan (referee) ; Roupec, Jakub (advisor)
The diploma thesis deals with the study of the behaviour of bidisperse MR fluids. The introduction gives brief research and analysis of previously published studies. In the main part of this thesis, the sedimentation properties of monodispersions and bidispersions are investigated influencing on the primary and secondary particles size, the ratio between the fractions, the total concentration of the particles dispersed in the MR fluid and the carrier fluid viscosity. The initialization sedimentation rate is used to assess sediment stability. Subsequently, MR samples are tested on a slit-flow rheometer, and flow curves are measured at different temperatures and in the presence of various magnetic fields intensities. The MR effect is evaluated by the yield stress. The study contains results describing the behaviour of investigated MR fluid samples.
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Design of GUI for Database PostgreSQL
Dvořáček, Ondřej ; Šimek, Václav (referee) ; Lukáš, Roman (advisor)
The bachelor's thesis describes the design and implementation of graphical user interface working with database system PostgreSQL. The final application allows users to execute basic and extended operations with tables. The design of this interface was built-up with Glade, programme which enables the development of user interfaces for the library GTK+. For the implementation of this application were used programming language C and library for accessing database server libpq. The main aim of this work is to develop free and multiplatform graphical interface that might be extended later.
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Civic facilities of Melnik town during years 1860-1939
Dvořáček, Ondřej ; Foltýn, Dušan (advisor) ; Hnilica, Jiří (referee)
This bachelor thesis deals with the development of institutions, buildings and facilities for civil purposes of the town of Mělník. It focuses on the founding and constructing of public serving institutions within the time span from the rise of civil society in the days of the Austrian-Hungarian Empire in about 1860 and their further development and changes during the First Republic. The time span leads up to the Nazi occupation of Bohemia and Moravia. The thesis aims at a description of the then founded institutions, namely, but not only, concerning education, culture and healthcare. Chapters are divided according to sectors of civil facilities. Key institutions are described in there in chronological order, as well as their architectural executions and their historical and architectonic characteristics in the context of the selected topic. Keys Words: civic facilities, Melnik town, First Czechoslovak Republic, Austria - Hungary, 19. century, 20. century, architecture
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Study on stability of bidisperse MR fluid and its magnetorheological effect
Dvořáček, Ondřej ; Mazůrek, Ivan (referee) ; Roupec, Jakub (advisor)
The diploma thesis deals with the study of the behaviour of bidisperse MR fluids. The introduction gives brief research and analysis of previously published studies. In the main part of this thesis, the sedimentation properties of monodispersions and bidispersions are investigated influencing on the primary and secondary particles size, the ratio between the fractions, the total concentration of the particles dispersed in the MR fluid and the carrier fluid viscosity. The initialization sedimentation rate is used to assess sediment stability. Subsequently, MR samples are tested on a slit-flow rheometer, and flow curves are measured at different temperatures and in the presence of various magnetic fields intensities. The MR effect is evaluated by the yield stress. The study contains results describing the behaviour of investigated MR fluid samples.
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Proposal to drive the fan impeller for ripening chamber
Dvořáček, Ondřej ; Strecker, Zbyněk (referee) ; Dvořáček, Jiří (advisor)
The Bachelor’s thesis deals with a structural design of proposal to drive the fan impeller with vertical axis of rotation for ripening chamber. The introduction gives a brief description of types, parts and operating principles of air conditioned chambers in meat technology. The second part of this work is focused on the design of belt drive, impeller bearing housing and electric motor layout. Thesis contains fundamental engineering calculations for horizontal and vertical axis positions as well as technical drawings.
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Design of GUI for Database PostgreSQL
Dvořáček, Ondřej ; Šimek, Václav (referee) ; Lukáš, Roman (advisor)
The bachelor's thesis describes the design and implementation of graphical user interface working with database system PostgreSQL. The final application allows users to execute basic and extended operations with tables. The design of this interface was built-up with Glade, programme which enables the development of user interfaces for the library GTK+. For the implementation of this application were used programming language C and library for accessing database server libpq. The main aim of this work is to develop free and multiplatform graphical interface that might be extended later.
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Querying Spatio-Temporal Data of Moving Objects
Dvořáček, Ondřej ; Kolář, Dušan (referee) ; Zendulka, Jaroslav (advisor)
This master's thesis is devoted to the studies of possibilities, which can be used for representation of moving objects data and for querying such spatio-temporal data. It also shows results of the master's thesis created by Ing. Jaroslav Vališ, that should be used for the solution of this master's thesis. But based on the theoretical grounds defined at the beginning of this work was designed and implemented new database extension for saving and querying spatio-temporal data. Special usage of this extension is demonstrated in an example application. This application uses the database extension for the implementation of its own database functions that are domain specific. At the conclusion, there are presented ways of the farther development of this database extension and the results of this master's thesis are there set into the context of the following project, doctoral thesis "Moving objects database".
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