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Measurement of diffusion coefitients by use of magnetic resonance
Král, Jakub ; Gescheidtová, Eva (referee) ; Bartušek, Karel (advisor)
This Bachelor thesis is focused on imaging techniques based on the principles of nuclear-magnetic resonance. These techniques are one of the most modern studies of physical, chemical and biological properties of substances. Introduction of this work is focused primarily on physical principles. Further in this work attention is given to the method of the PFG-SE but also to more modern multiinterval NMR methods, which removes the systematic measurement errors for heterogeneous materials. Part of the work is also devoted to b-factor calculations for various kinds of pulse sequences. In last part the work is devoted to data processing in Matlab and Marevisi. Selected method from the beginning of the work is than used to measure the diffusion and processing of tissue cultures.
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Computational simulation of the compression test of the open cell metal foam
Homola, Václav ; Skalka, Petr (referee) ; Ševeček, Oldřich (advisor)
The thesis presents computational simulation of compression test of a nickel foam and the 3D reconstruction of micro-CT images was utilized to generate the foam’s model of geometry. Explicit FEM is used to simulate compression test using software tool LS-DYNA and the stress–deformation curve is obtained together with deformed model’s mesh used for subsequent analysis. Sensitivity analyses were performed to configure the model and ensure best fit with values obtained during real-life experiment. The ANSYS Classic environment was then used to simulate tensile test of the foam compressed to various thicknesses. The tensile moduli in three mutually perpendicular directions of nickel foam were computed and the results were compared to experimental values as well. The results of tensile test simulation revealed considerable anisotropy of the foam’s elastic behavior. It can be said that the measured experimental data correspond very well with the elastic properties obtained from simulation up to certain level of compression. Analysis of the relationship between the element size and tensile moduli showed a significant difference between fine and coarse mesh. The optimal level of discretization and the overall model configuration ensuring high level of accuracy is proposed in this thesis.
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Synthesis of novel zeolite materials and their application in catalysis
Veselý, Ondřej ; Přech, Jan (advisor) ; Zima, Vítězslav (referee) ; Hronec, Mlan (referee)
Zeolites are crystalline microporous tectosilicates with acidic properties. The pore sizes of molecular dimensions restrict molecules from entering/exiting the pores based on the molecule size and geometry, or formation of certain (bulky) transition states within the pores. Accordingly, zeolites have become vital industrial catalysts, adsorbents and ion-exchangers. Zeolites are commonly synthesised by hydrothermal crystallization. However, this method provides only limited control over their crystal structure, morphology, or location of active sites within the framework. Some of these limitations can be overcome using an alternative synthetic method; the Assembly-Disassembly-Organisation- Reassembly (ADOR). The ADOR transforms a parent (germanosilicate) zeolite into a layered precursor and subsequently uses the layers as building blocks for a new zeolite framework. We aimed to develop methodology to control the crystal morphology of germanosilicate zeolite UTL (Assembly), determine the mechanism of the UTL hydrolysis (Disassembly), and to reconstruct the parent UTL zeolite from the ICP-1P layered material (Organisation and Reassembly) since the traditional ADOR yields zeolites of smaller channel size but the parent UTL. We found the UTL crystal morphology progressively varies the Si/Ge molar ratio...
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Computational simulation of the compression test of the open cell metal foam
Homola, Václav ; Skalka, Petr (referee) ; Ševeček, Oldřich (advisor)
The thesis presents computational simulation of compression test of a nickel foam and the 3D reconstruction of micro-CT images was utilized to generate the foam’s model of geometry. Explicit FEM is used to simulate compression test using software tool LS-DYNA and the stress–deformation curve is obtained together with deformed model’s mesh used for subsequent analysis. Sensitivity analyses were performed to configure the model and ensure best fit with values obtained during real-life experiment. The ANSYS Classic environment was then used to simulate tensile test of the foam compressed to various thicknesses. The tensile moduli in three mutually perpendicular directions of nickel foam were computed and the results were compared to experimental values as well. The results of tensile test simulation revealed considerable anisotropy of the foam’s elastic behavior. It can be said that the measured experimental data correspond very well with the elastic properties obtained from simulation up to certain level of compression. Analysis of the relationship between the element size and tensile moduli showed a significant difference between fine and coarse mesh. The optimal level of discretization and the overall model configuration ensuring high level of accuracy is proposed in this thesis.
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The preparation of porous materials for radionuclide capture
Bajzíková, Anna ; Smrček, Stanislav (advisor) ; Hrubý, Martin (referee)
Title: The Preparation of Porous Materials for Radionuclide Capture Author: Bc. Anna Bajzíková Curriculum: Teaching of Chemistry and Biology for Secondary Schools Type of thesis: Master's Department: Department of Teaching and Didactics of Chemistry, Faculty of Science, Charles University in Prague Elaborated: Department of Nuclear Chemistry, Faculty of Nuclear Sciences and Psysical Engineering, Czech Technical University in Prague Advisor: Doc. Ing. Stanislav Smrček, CSc. Consultant: RNDr. Ján Kozempel, Ph.D. Abstract: The use of radionuclides is still increasing and with it also increases the amount of radioactive waste and this waste have to be processed. This thesis is focused on the preparation, characterization and testing of porous materials which could be used for the process of this waste. There were prepared and characterized materials based on silica and zirkonia with a modified surface. For the modification were used styren with divinilbenzene, polyacrilonitrile and diglycolamides at different configurations of these materials. Furthermore, there were prepared materials based on hydroxyapatite and its modifications. Prepared sorbents were tested for radionuclide capture - flow through the column and also in the static experiments. The capture of 227Ac and its daughter's radionuclides...
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The preparation of porous materials for radionuclide capture
Bajzíková, Anna ; Smrček, Stanislav (advisor) ; Čuba, Václav (referee)
This thesis is focused on the preparation of porous materials which may be usable for radionuclide uptake. These characteristics can be found at nanoporous materials (size of pores 1 - 100 nm) or at polymers. Nanoporous metal oxides and silica gel with styrene-divinylbenzene-TODGA modified surface were prepared and characterized for this purposes. All new prepared substances were tested for the efficiency of radionuclides capture. These measurements were done in Ústav jaderného výzkumu in Řež or in our laboratory.
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Measurement of diffusion coefitients by use of magnetic resonance
Král, Jakub ; Gescheidtová, Eva (referee) ; Bartušek, Karel (advisor)
This Bachelor thesis is focused on imaging techniques based on the principles of nuclear-magnetic resonance. These techniques are one of the most modern studies of physical, chemical and biological properties of substances. Introduction of this work is focused primarily on physical principles. Further in this work attention is given to the method of the PFG-SE but also to more modern multiinterval NMR methods, which removes the systematic measurement errors for heterogeneous materials. Part of the work is also devoted to b-factor calculations for various kinds of pulse sequences. In last part the work is devoted to data processing in Matlab and Marevisi. Selected method from the beginning of the work is than used to measure the diffusion and processing of tissue cultures.
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