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Flow visualization methods
Ďurdina, Lukáš ; Jedelský, Jan (referee) ; Lízal, František (advisor)
ĎURDINA, L. Flow visualization methods. Brno: Brno University of Technology, Faculty of Mechanical Engineering, 2010. 45 p. Thesis supervisor Ing. František Lízal. This thesis deals with fluid flow visualization methods with respect to their practical application possibilities. Chronological description of the historically valuable visualization experiments emphasises the role of visualization in the experimental fluid mechanics. A brief characteristic of the flow field contains mathematical description of the objects, which can be visualized. Visualization methods are divided into experimental and computer aided methods. Individual methods are ordered subsequently beginning with those with lowest requirements for equipment to the more sophisticated methods. Various techniques, which provide qualitative and quantitative description of the tested gas or liquid flow, are described. The overview for the choice of methods for various applications sums up the important facts from previous chapters. Description of a simple helium bubble flow visualization experiment realized in a lab can be found at the end of the thesis.
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Experimental study of fluid-induced instabilities in journal bearings
Stifter, Jan ; Polach, Pavel (referee) ; Omasta, Milan (advisor)
Presented diploma thesis deals with experimental study of fluid induced instabilities which occur in rotating machinery with journal bearings. The first part describes the oil whirl and oil whip instabilities. It also gives an example of optical methods used for observation of journal bearings. Next part is dedicated to modifications of an existing test rig that were necessary for carrying out experiments. Finally, there are presented results of experiments that define the effect of initial conditions on appearance of instabilities.
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Reliable visual systems
Honec, Peter ; Janáková, Ilona (advisor)
The Doctoral thesis demonstrates the design of reliable industrial visual systems. The special emphasis is dedicated to the detection of defects on webs in industrial applications based on line-scan cameras. This system makes possible detection and classification of defects originating during the real production conditions. This work covers a theoretical study of a visual system for the defect detection on endless bands as well as of appropriate lighting and the scene arrangement. Further to that have been selected, adjusted and designed key components of hardware. Following the design and optimization of algorithms a system prototype had been installed on non-woven textiles production line. Eight visual systems implemented into real-life industrial conditions based on this prototype
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Optical measurement of liquid surface tension
Malá, Kateřina ; Pech, Ondřej (referee) ; Malý, Milan (advisor)
This bachelor thesis explores the topic of measuring surface tension of liquids. The theoretical section explains the basic principles as well as possibilities of application of several measuring methods. In the next part, the most suitable method is selected in terms of ease of use, accuracy and purchase cost. The pendent drop method has been found to fit these criteria. The experimental section of the thesis describes the measuring apparatus and the analytic tool used. The results comprise an analysis of the factors which may affect the measurement precision as well as a comparison of an automatic and a manual analysis, and a reference measurement that confirms the aperture as efficient at measuring surface tension of liquids.
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Traffic assistant system for complicated situations
Podola, David ; Janáková, Ilona (referee) ; Petyovský, Petr (advisor)
T-intersections are one of the most common places where collisions happen. An intelligent traffic mirror is one the possible solutions to reduce the accident rate. The mirror detects the situation around the intersection, process the data and provides the driver with an information, whether the situation is safe and the driver can enter the junction safely. The aim of the thesis is a feasibility study of reliable detection of non-stationary objects based on cameras. The core of the intended product – the detection algorithm – detected the object on short distance from the camera reliably but as the distance was growing, the detection quality degraded. One of the possible solutions to achieve better detection results on longer distances may be achieved by using a camera with greater zoom. Based on the example improvement proposal, the feasibility of the solution based on optical methods was finally confirmed.
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Wear analysis of extracted polyethylenes of total hip replacements using optical methods
Přikryl, Adam ; Morovič, Ladislav (referee) ; Vrbka, Martin (advisor)
An experimental methodology for wear assessment of extracted polyethylene hip implants was designed in this diploma thesis. Methodology uses optical 3D scanner and optical profilometer for analysis of wear. Designed methodology for wear analysis was validated by gravimetric method. The results of validation were in good agreement with the increase of wear rate. Validation results show that the methodology is not suited for wear assessment of metal and ceramic implants which have small wear rates. On the other hand the methodology is more than useful for wear assessment of polyethylene implants. Designed methodology for wear assessment was applied on the set of thirteen extracted polyethylene hip implants. Results of the wear analysis were wear volumes and linear wear noted in the wear maps. Roughness of the surface was measured on explanted cups and results were noted in the roughness map. On articulating surface of the cups different areas were observed for measured roughness. Those areas were described as area with machining marks from manufacturing process, polished area from combination of abrasive and adhesive wear, polished area from micro-contact fatigue and area including plastic deformation.
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Laser Doppler anemometry
Osička, Tomáš ; Lízal, František (referee) ; Jedelský, Jan (advisor)
This bachelor thesis deals with laser Doppler anemometry (LDA). It is a modern, non-intrusive flow measurement technique. The work deals with theoretical principles and components of the method. The experimental part is devoted to setting of the system. Vector plot and profile plot display the measurement results.
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Application of optical methods for determining the deformation of bodies
Kováříková, Sabina ; Šebek, František (referee) ; Návrat, Tomáš (advisor)
This Bachelor’s thesis is focused on application of digital image correlation method for determining the deformation of bodies. It contains theoretical knowledge about this method and realization of measurements on selected bodies. The aim of the thesis is to compare experimentally obtained results with the results, obtained in software Ansys Workbench. The Bachelor’s thesis also contains characteristics of other optical methods, used for determining the deformation of bodies and research of software, which can be used for data processing, based on DIC method.
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Remote fault monitoring system
Jarůšek, Jakub ; Trčka, Tomáš (referee) ; Škarvada, Pavel (advisor)
In practice, optical non-contact measurement of distance and displacement is divided into various methods that use a different parameter of the optical (light) signal. Some methods are explained in the work. The triangulation method is described in more detail. This method is used to measure and monitor the displacement of geological faults. For this monitoring, a low-budget device is designed, which uses lasers and a sensor to determine the displacement of the measured object in a certain time interval. The whole system will serve as verification of data measured by magnetoresistive sensors.
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Design and realization of experimental equipment for determination of residual stress of bent samples
Novotný, Lukáš ; Návrat, Tomáš (referee) ; Krejčí, Petr (advisor)
The master thesis is focused to design and realization of experimental equipment for researching of residual stress determination for specimen with non-uniform distribution stress along the depth. Literature search study of problematic was performed and it was used for elaboration of chapters about origin of residual stress, their classification and chapters about methods, which are used for measuring of residual stress and their determination. The following part explains the design of experimental equipment and stress-strain analysis of selected parts of this equipment. Then the final design of equipment is presented, including complete production drawings, and it’s explained final assembling of experimental equipment. Final chapter is devoted to examinable loading of specimen.
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