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Design and execution of additional module of laboratory equipment for measurement of friction within lubricated contacts
Stifter, Jan ; Šperka, Petr (referee) ; Frýza, Josef (advisor)
This bachelor‘s thesis presents the design and implementation of a module of laboratory device for measuring coefficient of friction and friction forces in elastohydrodynamic lubricated contacts. The module is able to measure friction forces in two perpendicular axes. A motivation for realization of this module was the absence of a similar equipment. The retrieval section of this thesis is dedicated to tribology, strain gauges (force sensors) and compliant mechanisms. The selection of the appropriate concept of the module and the force transducers is solved in the design part of thesis. The compliant mechanism with flexure hinges was designed via FEM analysis. This mechanism allows the displacement of the contact member of module in the direction of the frictional forces acting within a lubricated contact. The proposed module was manufactured, implemented in laboratory equipment and its functionality was tested. According to preliminary results, the module fulfilled the objectives of this thesis.
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Gas flow measurement
Slováček, Antonín ; Šedivá, Soňa (referee) ; Beneš, Petr (advisor)
The diploma thesis brings a description and realization of new measuring devices which are designed to support student´s laboratory practice of air flow measurement techniques. The new devices and laboratory exercises help students get experience of several methods of measuring which they get to know during mandatory Bachelor's and Master's study programmes. The paper also includes a theoretical background, the knowledge of which is necessary for mastering the issue. Moreover, the paper comprises a literary search of sensors and a market research. The second part of the thesis presents possibilities of the laboratory workplace, and the results of the measurements of the new laboratory devices used for sample laboratory exercises.
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Laboratory device focused on the switched capacitor circuits
Urban, Lukáš ; Šotner, Roman (referee) ; Petržela, Jiří (advisor)
This Master`s thesis is focused on through acquaintance of principles of the function circuits with switched capaticors and posibility of their application mainly in frequency filters or signal generators. The origin of the switched capacitor circuits is mentioned at the beginning of the work. There are references to the first scientific work and scientists who have dealt with this issue. Maxwell`s idea: lossy element (resistor) replace with lossless element (switched capacitor) in electric circuit, is further described. In the next chapter of this work are listed types of switching capacitors and their use in simple RC filters and in structures of inverted or noninverted integrators and their application in more complex higher order filters. The advantages and disadvantages of SC circuits versus circuit composed of discrete components are shown. It is also listed a simple low-pass switched RC filter implemented with analogue multiplexer 4053. Using the LTC1043 integrated circuit, which structure and properties are described and analyzed in detail in the work, the 1st order aktive or pasive low and high pass filters were designed and subsequently simulated in the computer simulator OrCAD PSpice v.10. Another chapter deals with the integrated circuits higher order filters, structure and properties of the integrated filter LTC1060 are further analyzed here. Except this IC there are mentioned integrated filters commercially less available from the corporations Linear Technology and Maxim. The main objective of thesis was to propose and establish laboratory device and laboratory measurment focused on the switched capacitor circuits. The laboratory device has been designed with integrated circuits LTC1043 and LTC1060, which is demonstrated by using passive and active integrator, 2nd order band-pass and 4th order band-pass with Chebyshevovou approximation.
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