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SMV-2023-09: Design and deposition of thin film optical coatings
Pokorný, Pavel ; Oulehla, Jindřich
A study of the possibilities of optical filters production. The optical properties of the filters must comply with those required by the customer. Theoretical calculations are verified by depositing a series of samples by means of electron beam evaporation. In particular, low pass and high pass filters, dichroic mirrors, spectral transmittance correcting filters, antireflective coatings and beam splitters for various angles of incidence will be tested.
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Drive system by serial connection of rotary hydromotors
Pokorný, Pavel ; Knoflíček, Radek (referee) ; Omes, Jiří (advisor)
The thesis deals with the problem of large-capacity manipulation of large forgings with forging manipulator. It describes current techniques, their characteristics, advantages and disadvantages. Based on the analysis of these techniques, the thesis introduces design of the connection of the hydraulic circuit for the drive of the traveling traction wheels of the forging manipulator QKK 100 by ŽĎAS a.s. focusing on simplicity, trouble-free operation, efficiency, economy, change of speed and torque, and possibility of modification according to the current load.
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Flow Measurement Using Dilution Methods
Pokorný, Pavel ; Jiřík, Radovan (referee) ; Harabiš, Vratislav (advisor)
The bachelor thesis focuses on the construction of a program in LabVIEW to measure pH with the Vernier sensing probe connected through the interface LabPro and to be able to inset the measured data with a physical model of a dilution curve to get information about the model. It further describes the necessary requirements of the product in which the measurement of the dilution curve would be possible, the principle of constructing it and its usage with the above mentioned program to construct a laboratory task.
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Tyre Parameters Measurement
Pokorný, Pavel ; Vančura, Jan (referee) ; Blaťák, Ondřej (advisor)
It is the tyre that ensures the interaction between a wheel and road surface and it is the the tyre which also acts as a primary cushioning. Its construction, features and condition highly influence driving properties of a car and thus passenger safety as well. In motorsports the tyre is a key part of the vehicle and therefore it is necessary to make use of its complete potential for reaching the best results. The aim of this thesis is a device construction suitable for tyre parameter and their characteristics measurement. The next task is to design a measuring system for tyre pressure and temperature monitoring. With using of these devices a few real-tyre measurements and subsequent result evaluation will be done. The output of the thesis is an overview of construction details, overview of selected tyre parameters, design and drawing documentation of multipurpose measuring device and the results of my measurements.
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Residual fatigue life estimation of railway wheelset
Pokorný, Pavel ; Zouhar, Michal (referee) ; Náhlík, Luboš (advisor)
The first part of this master's thesis deals with the high cycle fatigue of materials, especially on growing cracks using linear elastic fracture mechanics. Much of this work is focused on the concept of stress intensity factor. This concept is nowadays one of the most widely used concepts for describing a body with crack. The first part ends with theoretical approaches to determine the residual fatigue life of the body with a crack. The second part of this master's thesis is focused on the determination of residual fatigue life of a specified railway wheelset. An existence of crack-like defect is assumed at the railway wheelset. The goal of this master's thesis is to estimate how long it will take to grow from initial defect to a critical crack length. The last part of this master's thesis is devoted to addiction order load cycles on crack growth rate.
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RESIDUAL FATIGUE LIFETIME OF RAILWAY AXLES
Pokorný, Pavel ; Fajkoš,, Rostislav (referee) ; Materna, Aleš (referee) ; Náhlík, Luboš (advisor)
This Ph.D. thesis deals with methodology for determination of residual fatigue lifetime of railway axles based on damage tolerance approach. This approach accepts an existence of potential defect, which could lead to fatigue failure of whole axle. The behavior of crack in railway axle is described by approaches of linear elastic fracture mechanics. There are plenty of factors, which more or less influence determined residual fatigue lifetime. The aim of this thesis is to quantify effects of these factors. The first part of Ph.D. thesis represents overview of studied problems relating to fatigue damage of railway axles. This part is focused on parameters, which influence fatigue crack growth in railway axle materials. The second part of thesis shows procedure for determination of residual fatigue lifetime, which was developed at the Institute of Physics of Materials of the Academy of Sciences of the Czech Republic. The main aim of this thesis was to improve current procedure for more precise estimation of residual fatigue lifetime. Significant part of this work is determination of significance of studied factors, which influencing calculated residual fatigue lifetime of railway axles (e.g. effect of threshold value, load spectrum, retardation effects, residual stress, axle geometry, material of axle etc.). The procedures described and results obtained can be also used for determination of residual fatigue lifetime of general mechanical component (not only railway axles). Therefore, results obtained in this Ph.D. thesis can be used e.g. for assessment of regular inspection intervals of cyclically loaded general mechanical parts.
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