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Mechanical Properties of Microstructural Components of Inorganic Materials
Wasserbauer, Jaromír ; Palou, Martin (referee) ; Drábik,, Milan (referee) ; Havlica, Jaromír (advisor)
Disertační práce se zabývá studiem strukturních a mechanických vlastností anorganických materiálů. Cílem je nalezení jednotlivých fází ve zkoumaném materiálu a hlavně lokalizace (mechanicky) nejslabšího místa, jeho ovlivnění a následně výroba materiálu o lepších mechanických vlastnostech. Z důvodu velkého množství použitých metod je základní teorie vložena vždy na začátku příslušné kapitoly. Taktéž z důvodu značného množství výsledků jsou na konci kapitol uvedeny dílčí závěry. Práce je rozdělena na tři části, kdy první se zabývá seznámením s možnostmi modelování mikro-mechanických vlastností a provedením experimentů umožňujících posouzení rozsahu platnosti některého modelu. V druhé části je provedeno shrnutí současných možností indentačních zkoušek pro měření mechanických vlastností strukturních složek betonu a praktické zvládnutí metodiky vhodné k užití pro výzkum materiálů zkoumaných domovským pracovištěm. V třetí části je navržena metoda identifikace nejslabších článků struktury anorganických pojiv a její ověření na konkrétním materiálu zkoumaném na domovském pracovišti. V této dizertační práci jsou použity tyto metody: kalorimetrie, ultrazvukové testování, jednoosá pevnost v tlaku, nanoindentace, korelativní mikroskopie a rastrovací elektronová mikroskopie s energiově disperzním spektrometrem. Dílčími výsledky jsou kompletní charakterizace cementových materiálů, upřesnění stávajících poznatků a nalezení optimálního postupu pro charakterizaci. Hlavním výsledkem je inovativní přístup vedoucí k pozitivnímu ovlivnění materiálu.
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Comparison of microscopic diagnostic methods
Veselý, Jakub ; Tihlaříková, Eva (referee) ; Čudek, Pavel (advisor)
This thesis deals with the description and comparison of diagnostic methods, transmission electron microscopy, scanning electron microscopy and atomic force microscopy. The introduction is a description of diagnostic methods. The following experimental section dealing with the diagnosis of ferritic chromium steel sample methods of scanning electron microscopy, atomic force microscopy, transmission electron microscopy and the evaluation and interpretation of measured results. The conclusion provides a comparison, the advantages and disadvantages of diagnostic methods.
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Study of the electrode materials for Li-Ion accumulators by electron microscopy
Kaplenko, Oleksii ; Čudek, Pavel (referee) ; Kazda, Tomáš (advisor)
The aim of this work is to describe the influence of temperature on the structure and chemical composition of electrode materials for Li-ion accumulators. Theoretical part of this thesis contains described terminology and general issues of batteries and their division. Every kind of battery is provided with a closer description of a specific battery type. A separate chapter is dedicated to lithium cells, mainly Li-ion batteries. Considering various composition of Li-ion batteries, the next subchapters deeply analyzes the most used cathode (with an emphasis on the LiFePO4, LiMn1/3Ni1/3Co1/3O2) and anode materials (with an emphasis on the Li4Ti5O12). The next chapters describe the used analytical methods: electron microscopy, energy dispersion spectroscopy and thermomechanical analysis. The practical part is devoted to the description of the individual experiments and the achieved results.
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Toxicity study of antimicrobial wound dressings and perspective novel nanomaterials
Kozlíčková, Hana ; Vojtová, Lucy (referee) ; Zajíčková, Lenka (advisor)
This bachelor thesis deals with the study of toxicity of selected commercial antimicrobial wound dressings (StopBac STERILE, containing silver ions and Traumacel Biodress Disinfect, containing chlorhexidine) and antimicrobial nanomaterial, provided by CEITEC BUT laboratories. The experimental part of the work describes the preparation of this polycaprolactone nanomaterial, on which a layer of copper was subsequently deposited by the magnetron sputtering system BESTEC (MAGNETRON). Furthermore, a method was designed to study the cytotoxicity of individual shelters with antimicrobial additives. These tests were performed in vitro on cell cultures by leaching the materials in the laboratories of the Faculty of Science, Masaryk University in Brno. We found that, with the exception of chlorhexidine, low concentrations of active substances extracted from the materials promoted the proliferation of the studied cells, while at high concentrations there were also cytotoxic effects. The analysis of individual materials was also performed using scanning electron microscopy and energy dispersive X-ray spectroscopy.
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Study of preparation of ceramic membranes
Matějková, Michaela ; Částková, Klára (referee) ; Bartoníčková, Eva (advisor)
In this bachelor thesis the literature retrieval concerning the preparation of ceramic membranes suitable for power applications (membrane reactors, fuel cells) and materials suitable for their preparation, was summarised. Based on that literature retrieval the glycine-nitrate syntheses of selected ceramic materials were performed. As starting material was chosen zirconate structure (Zr-Ba-O), which was doped by cerium, iron, aluminium and manganese ions. The resulting powders were further processed to solid membranes by unaxial pressing and sintering (density of sintered bodies about 93 % t. d.). Then the influence of dopants on the properties of the powders and ceramic membranes were studied. The evaluation of properties (as phase composition, powders morphology and microstructure of ceramic bodies) was performed by x-ray analysis, scanning electron microscopy, a specific surface analysis and simultaneous thermal analysis.
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PEG-based semi-interpenetrating polymer network hydrogels
Kadlecová, Michaela ; Kalina, Michal (referee) ; Sedláček, Petr (advisor)
This bachelor's thesis deals with optimization of the preparation of hydrogels based on polymer networks of polyehtylene glycol with the incorporation of a semi-interpenetrating polymer networking and the following chemical-physical characterization of the prepared hydrogels. Polyehtylen glycol diacrylate was chosen from the range of polyethylene glycol modifications as a model material for the formation of hydrogels. Based on this, the preparation using UV photopolymerization was optimized. After optimization of the preparation, selections and following incorporation of the polyelectrolyte took place. Sodium polystyrene sulfonate was chosen as a model polyelectrolyte. Then, there was a basic characterization and comparison of the prepared hydrogels based on polyethylene glycol diacrylate with and without the addition of polyecletrolyte. Swelling, rheology, scanning electron microscopy were used for basic characterization and transport characteristics were investigated using diffusion.
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Direct Imaging of Deformation of Metallic Materials by Means of Slow Electrons
Piňos, Jakub ; Kolíbal, Miroslav (referee) ; Kasl, Josef (referee) ; Frank, Luděk (advisor)
Scanning electron microscopy is one of the common tools for the analysis of advanced engineering materials. The development of various techniques allows choosing an appropriate mode of observation to obtain new information about sample structure and properties. The thesis deals with direct imaging of deformation in metal samples by scanning low energy electron microscopy during the in-situ tensile test. Experiments were performed on pure copper samples. Images obtained during the tensile test allow us to observe the effect of deformation in the structure of metal from the first appearance of these effects in structure at deformation intensities about 3-4% up to extreme plastic deformation at the crack tip.
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Toxicity study of antimicrobial wound dressings and perspective novel nanomaterials
Kozlíčková, Hana ; Vojtová, Lucy (referee) ; Zajíčková, Lenka (advisor)
This bachelor thesis deals with the study of toxicity of selected commercial antimicrobial wound dressings (StopBac STERILE, containing silver ions and Traumacel Biodress Disinfect, containing chlorhexidine) and antimicrobial nanomaterial, provided by CEITEC BUT laboratories. The experimental part of the work describes the preparation of this polycaprolactone nanomaterial, on which a layer of copper was subsequently deposited by the magnetron sputtering system BESTEC (MAGNETRON). Furthermore, a method was designed to study the cytotoxicity of individual shelters with antimicrobial additives. These tests were performed in vitro on cell cultures by leaching the materials in the laboratories of the Faculty of Science, Masaryk University in Brno. We found that, with the exception of chlorhexidine, low concentrations of active substances extracted from the materials promoted the proliferation of the studied cells, while at high concentrations there were also cytotoxic effects. The analysis of individual materials was also performed using scanning electron microscopy and energy dispersive X-ray spectroscopy.
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Utilization of various methods of porosimetry in investigation of internal structure of biopolymer hydrogels
Zahrádka, Jan ; Pekař, Miloslav (referee) ; Sedláček, Petr (advisor)
The main aim of the thesis was to select, optimize and test suitable methods for studying inner structure of hydrogel materials. The study of the size of pores with potential use in fundamental and applied research of these materials is the central focus of the thesis. Firstly, a literature search was done in order to collect basic information about usefulness of the individual methods. On the basis of this literature search, the experimental part of the work was divided into several steps. First, selected methods of conventional porosimetry (mercury intrusion porosimetry, BET analysis and DSC thermoporometry) were applied on reference porous materials and the results obtained by the individual methods were compared. The methods optimized with the use of these reference materials were then utilized in the analysis of porosity of model hydrogels based on polyvinyl alcohol. Based on the results of this analysis, the usability and benefits of the individual methods were discussed with respect to the sample preparation, time and financial demands, and also from the viewpoint of compliance of the determined pore sizes with the range of sizes declared for the physical PVA gels.
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Růst Mycobacterium smegmatis na agarovém médiu a agarovém médiu pokrytém celofánovou folií - morfologická a proteomová studie
Ramaniuk, Volha ; Weiser, Jaroslav (advisor) ; Beranová, Jana (referee)
Biofilm formation is one of the most common bacterial survival strategies. Majority of bacterial species are able to form these three-dimensional structures, including pathogens like Mycobacterium tuberculosis. Representatives of Mycobacterium genus widely occur in the nature, although they can cause serious problems when they appear in medical equipment and artificial replacements of the human body. Non-pathogenic Mycobacterium smegmatis mc2 155 was used as a model organism in our experiments. We investigated morphology of the three- and six-day-old colonies (in fact biofilms) on agar and agar covered with cellophane using Stereo microscope and Scanning Electron Microscope. We found that a type of surface as well as a carbon source has a great influence on the morphology of the M. smegmatis colonies. We isolated proteomes from the agar and cellophane cultures and from planktonic culture. Two-dimensional electrophoresis was used as the main proteomic method. Proteomic data were analyzed using PDQuest software. Then the sets of proteins detected by qualitative and quantitative analyses were compared using Venn diagrams. As a result, we recognized 7 unique proteins that might be specific for recognition and adhesion of bacteria to the cellophane, no unique protein in agar proteome and 46 unique...
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