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Distributed control system for function of laboratory hydraulic model.
Janda, Tomáš ; Weber, Martin (referee) ; Pásek, Jan (advisor)
In the first part of this bachelor´s thesis are introduction common information about distributed control systems above all with a view to on their communications systems.The second part is devoted to hardware machines. There is described their functionalist and resulting configuration.The third part describes creation of software for operative PLC and it presents results of system in this period of progression. The next part inform at first about creation of visualization for existend system and afterwards describes its functionality. At the close there are summarized results of realized distributed control system.
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Risk Management in Electronic Business Operation
Janda, Tomáš ; Novák, Lukáš (referee) ; Koch, Miloš (advisor)
The diploma thesis deals with the issue of electronic commerce operation and risk analysis on a concrete example of a company that wants to break on the market through the internet shop. The thesis builds on a theoretical basis of e-business, e-commerce, e-shop features, information systems and risk engineering. Based on the theoretical backgrounds, were the risk analysis and suggestions made to prevent and potentially mitigate these risks to an acceptable level.
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Cyclic soil behaviour - numerical modelling and laboratory testing
Opršal, Jakub ; Mašín, David (advisor) ; Janda, Tomáš (referee)
Cyclic soil behavior is nowadays a popular subject of studies. One of its applications is geotechnical design and numerical simulation of foundation of offshore wind turbines. This master thesis is a part of a wider scientific research on cyclic soil behavior done at Charles University. One of the goals of this thesis is to define reference sand material, which could be used for another scientific projects. Therefore it was necessary to perform sufficient number of laboratory tests to create a representative volume of experimental data. Results and problems are commented in this thesis. The obtained experimental data are then used for calibration of hypoplastic model for sands. Numerical back analysis of cyclic loading of pile is also part of this work, where experimental data of pile cyclic loading is taken from the literature.
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Magnetooptical and magnetotransport effects in non-collinear antiferromagnets
Baďura, Antonín ; Schmoranzerová, Eva (advisor) ; Janda, Tomáš (referee)
In this thesis, we investigate the magnetic properties of an antiferromagnet Mn5Si3. Mn5Si3 shows two configurations of magnetic moments depending on temperature: the low-temperature phase (below 90 K) is noncollinear and noncoplanar, while the spin configuration is collinear at higher temperatures up to 240 K. Furthermore, the band structure of Mn5Si3 is spin-split in both antiferromagnetic phases via a specific nonrel- ativistic mechanism, referred as altermagnetism. We probed this spin-splitting by two distinct methods: Firstly, we characterized the transport properties of Mn5Si3 by mea- suring electronic and thermoelectric transport phenomena. Particularly, we detected the spontaneous Hall and Nernst responses in Mn5Si3 thin epitaxial films. The key outcome was a detailed analysis of the spontaneous Hall signal together with the observation of the spontaneous Nernst effect. In the second approach, we studied magnetooptical re- sponse of the thin films, where we focused on reflective geometry (the polar Kerr effect and the Voigt effect). We observed a pronounced signal in the Voigt geometry, which is quadratic in magnetization and could correspond to a magnetooptical signal. Further- more, we observed a change in optical response when the thin-film samples were exposed to a thermally-induced mechanical...
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Accounting for a spatial and experimental variability in numerical modelling of geotechnical structures
Kupa, Ondřej ; Mašín, David (advisor) ; Janda, Tomáš (referee)
This diploma thesis is focused on evaluation of influence of spatial and experimental variability of input data in numerical simulations of behaviour of geotechnical structures. Thanks to opportunity to use data source of sand from the only one location in order to evaluate spatial and experimental variability, the assessment was carried out using extracting the experimental uncertainty from the total spatial variability method. Primarily, an influence of different level of considered experimental variability on total response of material environment was investigated. Random field theory was used to model variabilities in parameters of geological underlay and Mohr-Coulomb ideal plastic constitutive soil model was taken into account. In order to achieve representative quantity of values for statistical quantification of resulting influence of considered variability level, Monte Carlo method was used. Presented method of extracting the experimental uncertainty from the total variability was verified on two geotechnical cases. First, a settlement of strip footing was solved. An increasing accuracy of settlement values depending on level of considered experimental variability was demonstrated. The second case was focused on assessment of variability influence on slope stability. In addition, a nonzero...
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Investigation of spin structure and dynamics in magnetically ordered thin films
Janda, Tomáš ; Němec, Petr (advisor) ; Hamrle, Jaroslav (referee) ; Reiss, Günter (referee)
Title: Investigation of spin structure and dynamics in magnetically ordered thin films Author: Tomáš Janda Abstract: This thesis is devoted to the development of methods for imaging and ultrafast manipulation of magnetic textures, such as magnetic domains and domain walls (DWs), and to the investigation of the corresponding magnetiza- tion dynamics. We focused on techniques that are, besides ferromagnets (FMs), applicable also to antiferromagnets (AFs), in particular, AF thin films. The employed excitation techniques were mostly based on direct or indirect effects of ultrashort laser pulses. We studied the DW motion induced by a transfer of angular momentum from circularly polarized femtosecond laser pulses in a FM GaMnAsP and we found that the observed macroscopic DW displacement is only possible due to its inertia. In a distinct experiment, picosecond current pulses were generated by an absorption of the ultrashort laser pulses in a verti- cal PIN diode-based photoconductive switch and used to excite a magnetic film deposited directly on top of the diode. For imaging of AF domain patterns, we developed a simple table-top laser-scanning technique, which is based on a magneto-thermoelectric response of the AF textures in the presence of a local laser-induced heating. We first used the method to image the...
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Development of calibration methods for hypoplastic models
Šula, Igor ; Mašín, David (advisor) ; Janda, Tomáš (referee)
The calibration application named ExCalibre was developed at Technical University in Prague, Faculty of Civil Engineering. This application can automatically process experimental data and create set of parameters of hypoplastic models which are designed for saturated clays or sands. The aim of this master thesis was to support development of application for calibration with testing it on real experimental data sets. Automatic calibration of these data sets was compared with calibration by hand for identical data. The development of the application and main phase of testing took place in two stages, where the main calibration errors of calibration application were identified. After the final testing of application where the minor bugs and errors were overcome a user-friendly web application (soilmodel.com/excalibre/) was introduced. This final testing has gone beyond this thesis. The results from the main phases of testing are discussed in this thesis as well as the description of database of fine-grained and coarse-grained samples which were used to testing of application. Knowing the calibration of the model is crucial for its using, you can find description of the used constitutive models in this thesis, which are used in the calibration application, as well as a description of procedure for...
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