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Losses Analysis of Induction Machines with Small Output Power
Mach, Martin ; Záskalický, Pavel (referee) ; Voženílek, Petr (referee) ; Hájek, Vítězslav (advisor)
The main objects of this doctoral thesis are analysis of a small induction motor losses and research of ways how to reduce losses and increase efficiency of this motor. The ways how to reduce losses and increase efficiency under study are as follow: reduction of stator winding’s resistance, lengthening of magnetic circuit, modification of turn number, cooper squirrel cage, slots shape optimization, sheets annealing and use of sheets with lower specific losses. The losses analysis and the research of ways how to reduce losses are done due to laboratory work. For this laboratory work, eleven different samples of the motor with above mentioned modifications were manufactured. Results of their measurements and losses analysis are presented in this thesis. There were also simulations by finite elements method used to help solve objects of this thesis. Due to the simulations, analysis of loses of the induction motor under study was done. Results of this analysis include some details that are not included in the results from measurement, for example separation of core losses between rotor and stator. The simulations were also used for analysis of manufacturing technology impact onto the motor’s performance. During this analysis, following impacts were considered: actual shape of magnetic circuit, stator’s sheets riveting, influence of cutting onto material’s properties and placement of the stator into conductive frame. Results of this analysis are presented in this thesis.
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Optimalization of CMOS Chip Interconnection Process for Higher Current Load
Novotný, Marek ; Mach,, Pavel (referee) ; Hulenyi,, Ladislav (referee) ; Szendiuch, Ivan (advisor)
This work deals with silicon chip interconnection with a view to high current up to 10A. A wire bonding method is used for interconnection. The first part of investigation is focused on the modeling and simulation by the help of program ANSYS. Thermo mechanical stressing and current density is important parts of this research. Stress and current density distribution are results of the first part. The experimental part describes transition resistance, electro migration and thermal process in the connection of wire and chip pad. A controlled current source (0 – 10A) is used for measurement. The current source makes it possible to 4-point method measurement with sampling rate 1,5MHz.
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Steam boiler for wood burning 40t/h
Mach, Ondřej ; Křemínský, pavel (referee) ; Skála, Zdeněk (advisor)
The purpose of this Diploma Thesis is the construction design of the steam-boiler for the combustion of biomass – wood pellets. For the specified parameters have been defined stoichiometric calculations and calculations enthalpy burnt gas. In sequence, there is designed and solved the configuraion of the steam-boiler, so that the result design and the number of the heat-delivery surfaces can be determined, in dependence on the required inlet parametres of the air and outlet parametresof the water vapour. These parametres mean the amount, the temparature and the pressure. The aim of the thesis is to make a design of the steam.boiler burning biomass according to the set parametres. This very ecological fuel can really substitute the fossil fuel and friendly respect the environment.
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The preparation of Grafen by method CVD
Procházka, Pavel ; Kromka,, Alexander (referee) ; Mach, Jindřich (advisor)
This diploma thesis is mainly focused on the fabrication of graphene layers on the copper foil by the Chemical Vapor Deposition (CVD). For this purpose the high-temperature chamber for the production of the graphene was completed and fully automated. The production of the high area graphene on the copper foil was experimentally achieved. The Raman microscopy and X-ray photoelectron spectroscopy measurements proved that the produced graphene is mostly a monolayer. Graphene layer was transferred on non-conductive substrate.
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Applications of Dictionary Learning Methods for Audio Inpainting
Ozdobinski, Roman ; Rajmic, Pavel (referee) ; Mach, Václav (advisor)
This diploma thesis discusses methods of dictionary learning to inpaint missing sections in the audio signal. There was theoretically analyzed and practically used algorithms K-SVD and INK-SVD for dictionary learning. These dictionaries have been applied to the reconstruction of audio signals using OMP (Orthogonal Matching Pursuit). Furthermore, there was proposed an algorithm for selecting the stationary segments and their subsequent use as training data for K-SVD and INK-SVD. In the practical part of thesis have been observed efficiency with training set selection from whole signal compared with algorithm for stationary segmentation used. The influence of mutual coherence on the quality of reconstruction with incoherent dictionary was also studied. With created scripts for multiple testing in Matlab, there was performed comparison of these methods on genre distinct songs.
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Advanced Methods of Audio Signals Interpolation
Pospíšil, Jiří ; Rajmic, Pavel (referee) ; Mach, Václav (advisor)
This diploma thesis deals with the theoretical analysis of the predictive methods of signal interpolation and signal modeling using sinusoidal model. On the basis of this theory the algorithm for the reconstruction of the missing sections in the audio signal is implemented in computing environment MATLAB. Results of mass testing reconstructions are displayed using objective methods SNR and PEMO-Q. Further experiments are carried out on single signals and their evaluation is described.
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Algorithms in colour management
Stecík, Július ; Mach, Václav (referee) ; Rajmic, Pavel (advisor)
Thesis briefly discusses the issues of color perception and effects associated with it. Further describes color model and its mathematical definition, which are used by color management. Briefly analyzes important elements of ICC profile. In second part two java applications were designed and programmed. First one evaluates visible spectrum and graphically demonstrate procedure for obtaining trichromacy information from this spectrum. Second application analyzes ICC profile and derives gamut of described device.
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Thin plasma polymer films on metal substrates
Mach, Pavel ; Salyk, Ota (referee) ; Přikryl, Radek (advisor)
The theoretical part of the thesis is focused on surface treatments, their evaluation from the point of view visual properties, plasma-enhanced chemical vapor deposition and analysis of thin layers prepared by plasma polymerization. The experimental part of the thesis deals with surface treatment of stainless steel AISI 304. Thin layers of pp-HMDSO (plasma-polymer) and of DLC are deposited on the steel´s surface for the purpose of preparing transparent layer, which protect steel´s surface against of making finger prints visible. As an objective method is chosen an immersion test in artificial sweat solution according to standard ČSN EN ISO 105-E04. Evaluation of the test is measured by a gloss-meter and by a colorimeter. Prepared layers are identificated by FTIR method.
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Vane pump
Mach, Jiří ; Jandourek, Pavel (referee) ; Klas, Roman (advisor)
This work gives basic information about vane pumps, especially with unbalanced construction and vanes led by rotor. The first chapter generally gives an attention to pumps. There are described basic information, classification, advantages and disadvantages of the types, characteristics and calculation relations. The following chapters describe the vane pumps in the way of classification, description of function and calculation relations. There is also made a practical calculation of vane pump according to the assignment accompanied by CFD analysis.
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