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Adhesion of a-SiOC:H films on planar substrates
Lepcio, Petr ; Salyk, Ota (referee) ; Čech, Vladimír (advisor)
This bachelor thesis deals with preparation of thin films of plasma polymers prepared by plasma-enhanced chemical vapor deposition. Tetravinylsilane was used as a monomer. Two sets of samples were prepared. Samples of the first set were prepared at different effective powers from pure tetravinylsilane and samples of the second set were prepared from deposition mixture of tetravinylsilane with different oxygen content at constant effective power. The film thickness was evaluated by spectroscopic ellipsometry and chemical structure by infrared spectroscopy. A scratch test was used to determine adhesion characterized by the critical normal load. An appearance of performed scratches was obtained by atomic force microscopy (AFM). Film adhesion influenced by the effective power and oxygen content in deposition mixture was discussed based on the received data.
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The Tensile Test of Tubes
Janda, Luděk ; Císařová, Michaela (referee) ; Peterková, Eva (advisor)
The present thesis deals with the tensile test of tube samples and verifies the possibilities of obtaining the corresponding material characteristics. In this work, a total of 3 types of tube samples made according to ČSN EN 10002-1were investigated. For the experiments, longitudinally welded tubes made of 17 240 steel were selected. The used tube was marked as a thin-walled one. Tensile tests were performed on 22 the samples, namely 8 samples on samples having a form of a cut-off of a full cross section tube, 10 samples a strip of segment cross section and a 4 samples transverse cut-out of tube. The goal of thesis was to validate options of acquiring material characteristics, value of deformation hardening exponent ,,n,, and material characteristic ,,C,, of tube samples. Further examination was aimed at designating which shape of sample tubes used for tension test is most suitable. And behaviour of individual samples was examined with tensile load applied. Tension tests were conducted on hydraulic test machine ZD40.
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Upgrade of the device for depositions by ion beam sputtering
Páleníček, Michal ; Mach, Jindřich (referee) ; Bábor, Petr (advisor)
This thesis deals with concept and realization of device which allows loading without air intake. Vacuum technology and its theoretical bases are discussed as well. Moreover the thesis is based on description of the current deposition chamber and its principles. The main part deals with the description of the concepts of lock and load systems. The first concept that has not been realized is described just briefly. The second one is thorough with description of the individual solutions and methods. The work also contains simple instructions how to install the specimen. At the end are described some outputs of simulations that have been done to comprehend and solve any problems that might occur as specimen holder cooling and deflection of magnetic rod.
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Stress analysis under torsion loading hard rubber for a large deformation and hyperelastic behaviour
Šulc, Petr ; Pešek, Luděk ; Bula, Vítězslav ; Cibulka, Jan ; Košina, Jan
The paper deals with a stress analysis of hard rubber under large torsion deformations. This study was motivated by effort to enhance the theoretical background for experimental evaluation of material behaviour of hard rubbers on our test rig. First the Mooney Rivlin model (MRM) for shear case of loading was developed and then MRM constants were attained by fitting of the MRM to the experimental torsion-deformation curve. Then the tuned MRM cylindrical model was tested under torsion loading for evaluation of stress state. Besides the radial distribution of shear stress and strain the attention was paid for evaluation of axial stresses. It could help to assess the influence of the tension stresses on the tangential deformations of the test sample during large torsion.
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The cause and effect of children and young people delinquency on the Cesky Krumlov region
KRÁKOVÁ, Zdeňka
The goal of my work is to establisch the cause and effect of children and young people delinquency on the Cesky Krumlov region. I suggested two hypothesis. I investigated the children and young people being under the curator{\crq}s supervision working in the town office of Cesky Krumlov. Here, there are two women employees. Each has a case load of a 160 children from the last year. I studied a third of them. It means 100 cases. As a method of verifying the hypothesis, I selected the method of document analysis and of case history analysis.
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Možnosti zjištění zatížení lesních ekosystémů těžkými kovy pomocí jejich obsahu v parazitech zaječí zvěře
Štefek, Karel
In this thesis the concentrations of heavy metals have been statistically appraised on the basis of samples gained from small intestines of European hare - Lepus europaeus and from an endoparasite Trichuris leporis (found by a washing method). Tha appraisal has been performed by atomic absorption spectrometry -- AAS, electrothermal atomization - ETA-AAS (for Cd, Cr, Ni, Pb), and means of atomization in the flame FAAS (Cu, Mn, Zn). The pieces of offal of hare game have been obtained from a common hunting in the localities of the Czech Republic represented by the region of South Moravia, Moravian-Silesian, Olomouc, and the Highlands. The sample collecting has been conducted from 2008 to 2012. Statistically significant differences of heavy metals concentrations have been found out between the individual localities. In addition, an endoparasite as a possible bioindicator of heavy metals load on the forest environment has been evaluated differently. Furthermore, in endoparasites there have been detected an exceeding of the hygiene limits for food. Conclusion made on the basis of all statistical analysis performed in this study says that Trichuris leporis indicates heavy metals load on ecosystems by wider range of heavy metals than the small intestine and more, considerably in the higher concentrations. Thus, Trichuris leporis can be used as a sentinel organism for the indication of heavy metals in the forest environment, at least in an area of the European hare territory.
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Analysis of fracture of quasibrittle materials using numerical modelling and acoustic/electromagnetic emission
Vodák, Ondřej ; Vořechovský, Miroslav (referee) ; Veselý, Václav (advisor)
This master thesis gives overview of non-destructive tests of concrete and provides detailed information concerning the acoustic and electromagnetic emission during monitoring of concrete failure. Conducted loading tests of plain concrete specimens are described in the thesis together with the performed numerical simulations of these tests in the software ATENA. The simulation results of concrete failure are analysed in detail and compared with the experimental results recording failure processes with the help of acoustic and electromagnetic emission. The majority of simulation results in software ATENA 3D show good agreement with the recorded data.
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Additional axial stress of rubber cylinder at torsion deformations and large strains
Šulc, Petr ; Pešek, Luděk ; Bula, Vítězslav ; Cibulka, Jan ; Košina, Jan
The paper deals with a stress analysis of hard rubber under large torsion deformations. This study was motivated by effort to enhance the theoretical background for experimental evaluation of material behaviour of hard rubbers on our test rig. First the Mooney Rivlin model (MRM) for shear case of loading was developed and then MRM constants were attained by fitting of the MRM to the experimental torsion-deformation curve. Then the tuned MRM cylindrical model was tested under torsion loading for evaluation of stress state. Besides the radial distribution of shear stress and strain the attention was paid for evaluation of additional axial stresses. It helps to assess the influence of the tension stresses on the tangential deformations of the test sample during large torsion strains.
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