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Temporally and spatially resolved diagnostics of an electric arc
Holcner, Oldřich ; Šimek, David (referee) ; Kloc, Petr (advisor)
This batchelor thesis "Temporally and spatially resolved diagnostics of an electric arc" deals with the investigation of plasma temperature in an arc formed by evaporation of copper wire. It is an optical method based on determination of temperature from intensity of spectral lines. In this batchelor thesis we explain how spectral lines are formed and how to determine the temperature. In the practical part we process discharge and show the time evolution of temperature at the measured points.
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DC arc extinguishing in low voltage switching devices for critical currents
Fencl, Martin ; Šimek, David (referee) ; Píška, Jakub (advisor)
This bachelor’s thesis deals with DC arc extinguishing for critical currents. The first, theoretical part describes and defines an arc, a DC arc and methods of its extinguishing. The second, theoretical part concerns spectral analysis – specifically, the emission method. Methods of research of extinguishing critical currents are also presented. The practical part consists of two measurements. The first measurement consists of spectrum measuring in time, in conjunction with voltage and current measurements. In the second measurement, the goal was to measure the dependence of arc burning time on voltage and current. The thesis concludes with summary of the results of each individual measurement and their presentation in the wider context.
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Design of MV contactor for railway application
Pala, Lukáš ; Šimek, David (referee) ; Valenta, Jiří (advisor)
In the introduction a traction circuit is analyzed with different types of electric devices. The thesis describes power railway electric circuits, their loads and types of used contactors. Railway standards chapter summarizes requirements of standards for railway contactors. Follows literature focusing on power current switching and power switching devices design. Based on previous, a design procedure is developed for railway MV contactor in accordance with end-user and standards requirements. Thesis closes with pre-designing a railway contactor by calculating electrodynamic forces, heatflow and mechanical components.
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Optimization of devices for deposition GaN nanostructures
Šimek, Daniel ; Voborný, Stanislav (referee) ; Mach, Jindřich (advisor)
This bachelor thesis deals with the automation of sources for the deposition of GaN nanocrystals used at the Institute of Physical Engineering. For the purpose of the thesis, the mechanism of automatic control of the gallium effusion cell shutter was designed and constructed and the control electronics containing components enabling automatic switching of the ion atomic source of nitrogen ions. In addition, samples of GaN nanocrystals on four different substrates that were studied for cold electron emission were prepared by the method of ion beam assisted molecular beam epitaxy IBA-MBE. The results of the measurement are discussed in the conclusion.
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Diagnostics of medium voltage and high voltage circuit breakers
Kapalla, Alexej ; Šimek, David (referee) ; Dostál, Lukáš (advisor)
This semestral work is about high voltage switchgears and their diagnosis. In this work there is part about history of HV switchgears and their dividing. Next part of this work describes diagnostic of HV switchgears VD4 24 ABB and AEG S1-245. In case of HV breaker VD4 there was provided diagnostics of new VD4 and used VD4. The measured values are then compared in the work and the influence of usage of breaker is presented according to his parameters. This work describes measurment of resistance of main contacts, insulation states.
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Design of a 25 kV traction disconnector
Buchta, Martin ; Bušov, Bohuslav (referee) ; Šimek, David (advisor)
This diploma thesis deals with the design of a traction disconnector for 25 kV AC and a rated current of 800 A. The result should be a competitive disconnector that is capable of potential applications on domestic railways and should have parameters that other local manufacturers do not currently offer. This is, for example, electrical strength or the size of the rated current, which is an economic option for most railway lines in the Czech Republic. According to the proposed drawing documentation, the disconnector was assembled and then the selected disconnector parameters were tested. For example, electrical strength tests, short-circuit tests, constant current tests, etc. were performed. The calculated and measured values were compared together. The designed disconnector was financially and technically evaluated on the basis of test results and the construction itself. Finally, some appropriate adjustments were proposed.
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Effect of a switching arc on design of low voltage switchgear
Šimek, David ; Bartlová, Milada (referee) ; Aubrecht, Vladimír (advisor)
The first part of the master thesis is focused on theoretical analysis of the problems of diagnostics of an electric arc physical properties. In the thesis there is shown identification of spectral lines in experimentally measured electric arc spectra. The thesis deals also with energy balance of the arc. Next part of thesis is aimed to theoretical analysis of effects of electric arc on construction materials of low voltage electric apparatuses. The main part of thesis is devoted to experimental measurement of arc radial temperature changes, measurement of cathode temperature and research of electrical arc effect on selected construction materials of low voltage apparatuses.
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Implementation of 2D Ultrasound Simulations
Šimek, Dominik ; Vaverka, Filip (referee) ; Jaroš, Jiří (advisor)
The work deals with design and implementation of 2D ultrasound simulation. Applications of the ultrasound simulation can be found in medicine, biophysic or image reconstruction. As an example of using the ultrasound simulation we can mention High Intensity Focused Ultrasound that is used for diagnosing and treating cancer. The program is part of the k-Wave toolbox designed for supercomputer systems, specifically for machines with shared memory architecture. The program is implemented in the C++ language and using OpenMP acceleration. Using the designed solution, it is possible to solve large-scale simulations in 2D space. The work also deals with merging and unification of the 2D and 3D simulation using modern C++. A realistic example of use is ultrasound simulation in transcranial neuromodulation and neurostimulation in large domains, which have more than 16384x16384 grid points. Simulation of such size may take several days if we use the original MATLAB 2D k-Wave. Speedup of the new implementation is up to 8 on the Anselm and Salomon supercomputers.
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Design of Data Warehouse in SaaS Company
Zetocha, Adam ; Šimek, Dominik (referee) ; Kříž, Jiří (advisor)
The diploma thesis consists of design and steps leading to build of data warehouse in startup developing SaaS product. Theoretical information about data warehouses and business intelligence are projected into design and following process of data warehouse development mainly for marketing data. Importing process of data into a data warehouse and reporting are fully automated.
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Technologies of the electrical apparatuses protyping
Svoboda, Filip ; Kloc, Petr (referee) ; Šimek, David (advisor)
The work focuses on the production of prototypes of electrical devices. The theoretical part contains a structured overview of the historical development of prototype production technologies and description of individual prototyping technologies. The main part of the work is the design of a prototype extinguishing chamber, printing of the chamber and verification of the ability to extinguish the electric arc.
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