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Pressure pulsation propagation in elastic hoses
Čapoš, Eduard ; Pochylý, František (referee) ; Habán, Vladimír (advisor)
This thesis deals with propagation of pressure and flow pulsations, which are strongly affected by the tube flexibility. There are two mathematic models introduced, which are derived from basic physical relations. First model assumes velocity only in the axis direction. Second one assumes also non-zero radial velocity. Kelvin-Voigt model for viscoelasticity was used. Furthermore, experimental measurement was designed and evaluated. Measured data was used to calculate material properties. In addition, dynamic transfer was determined.
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Investigation on the Interaction between Construction Materials and Switching Arc in Low Voltage Switching Devices
Šimek, David ; Slavíček, Pavel (referee) ; Mindl,, Pavel (referee) ; Kloc, Petr (advisor)
The doctoral thesis is focused on the interaction of construction materials and the switching arc in low voltage switchgear. An issue of selected low-voltage electrical devices, electric arc in electrical devices, and its diagnostics using optical emission spectroscopy and high-speed video are discussed at the theoretical level. The main part of the work is an experimental examination of samples of selected high-performance industrial plastics. A series of tests of resistance to an electric arc were performed on these plastics. The electrical parameters of the switching process, the weight losses of the material of the quenching chambers when applying various power parameters were evaluated from the experiments. The empirical equations were determined for the calculation of the loss of individual materials in a specific configuration. Furthermore, the influence of the used material on the behavior of the electric arc in the extinguishing chamber made of these plastics was investigated. A high-speed video was recorded, the time evolution of the pressure inside the chamber, the electrical parameters of the arc, and the time-resolved evolution of the radiation spectra were measured using atomic emission spectroscopy in these measurements. The relative composition of the plasma was identified from the radiation spectra, and the time evolution of the relative contamination of the discharge area by the main contact material and the selected vapors of the used plastics was created. The last important parameter of the electric arc is its temperature, which was also calculated from the radiation spectra. A comparison of individual plastics and their applicability for applications in contact with electric arc was performed based on the obtained data.
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Physical phenomena in air transport
Bělehrádek, Lukáš ; Uher, Pavel (referee) ; Rubinová, Olga (advisor)
The aim of this thesis is to design an air conditioning system of a flat unit in two variants of piping. The piping system of the first floor is installed into the floor in one variant, in the other it is in the ceiling. Data received from measurements within the experiment have been used for the design. The result of the measurement are minor loss coefficient implemented for bending pipes and pressure losses caused by rubbing. These values are used for dimensioning piping variants. Both types of piping are described in the theoretical part and the method of how the experiment had been processed.
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Switching arc diagnostics in DC contactor
Píška, Jakub ; Kloc, Petr (referee) ; Valenta, Jiří (advisor)
Cílem této diplomové práce bylo provést diagnostiku vysokonapěťového stejnosměrného stykače se zaměřením na zpětnou komutaci a lepení oblouku, navrhnout a ověřit úpravy, které odstraní tyto negativní jevy. Měření obloukového napětí, tlaku a pomocí rychlokamery byly použity při diagnostice těchto jevů. Změny na arcrunnerech a jhu magnetického obvodu byly využity při jejich odstraňování. Úpravy na arcrunneru zmenšily skokové nárusty délky oblouku a úpravy na jhu navýšily sílu na oblouk mezi rozevírajícími se kontakty. Navrhnuté změny na stykači snížily časovou ztrátu v důsledku zpětné komutace, a tak zkrátily čas přenosu oblouku.
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Workplace of flow and pressure measurement
Brabenec, Jiří ; Beneš, Petr (referee) ; Bejček, Ludvík (advisor)
The thesis deals with formation of a workplace for preparation gaseous mixtures and their future usage. The main goal of the thesis is testing of new materials which have suitable usage as catalysts. Gaseous mixture is prepared by calorimetric mass flow meters with control valve and multiposition microelectric valve actuators. The next part describes measuring of pressure and temperature and controlling of furnace temperature. The thesis deals with specifications of all devices, their circuitry, communication and program controlling. All devices are controlled by computer with program which is programmed in LabVIEW.
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Electronic Compass
Špaňhel, Petr ; Slaný, Karel (referee) ; Šimek, Václav (advisor)
This bachelor's thesis deals with a design and construction of equipment that should offer an easy approach to measurement of temperature, air pressure and angular orientation to the Earth surface. Subsequently, this set of infromation will be shown in a concise way on a graphic LCD display. The introductory chapter provides a general outline to the hardware conception, which primarily involves reading of data from sensors and their graphical visualization. Details on control firmware aspects are included in the following two chpaters. Fourth chapter is aimed at device operation and its user interface. Finally, evaluation of the results and conclusion is provided.
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Pressure monitor for microfluidic systems
Romaňák, Adam ; Sekora, Jiří (referee) ; Čmiel, Vratislav (advisor)
The diploma thesis deals with measuring pressure in microfluidic systems. The theoretical part of the work is devoted to microfluidics, pressure in liquids, pressure measurement, distribution of pressure sensors, and their specifications. Then follows the hardware and software solution of the measuring system for measuring the pressure in the microfluidic system using microprocessor technology. The practical part covers the hardware and software implementation of the measuring system.
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Design of equipment for hydrostatic pressure monitoring
Zahrádka, Michal ; Bražina, Jakub (referee) ; Pruša, Radomír (advisor)
The purpose of bachelor thesis is the design and manufacture of a leveling electronic hydrostatic device. Part of the thesis is a research for current leveling equipment and pressure measurement methods with emphasis on the measurement of hydrostatic pressure. The entire device is to be implemented on the Arduino development platform. The use of the assembled meter is assumed in the construction industry.
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