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Quantitative computed tomography
Šalplachta, Jakub ; Keckes, Jozef (oponent) ; Batenburg, Joost (oponent) ; Kaiser, Jozef (vedoucí práce)
The main aim of this thesis is to study, explore and possibly move further the field of quantitative computed tomography (QCT) with specific focus on a laboratory-based submicron computed tomography (CT) system Rigaku nano3DX. This work is dealing with both aspects of the QCT, which are the acquisition of quantitative CT data and the utilization of CT data for quantitative analysis. Regarding the first aspect, specific focus is placed on assessment of current technological limits of submicron CT, where the technology-based tomographic artifacts are studied, and optimal reduction strategies are proposed. Also, practical aspects related to implementation of spectral CT in a form of dual-target CT (DTCT) using Rigaku nano3DX system, are solved by development of dedicated acquisition and data registration methodologies. For the quantitative analysis of CT data, two novel methods were developed. One was specifically designed for porosity analysis of additive manufactured samples with a respect to the crucial points of tomographic data processing, making it objective and reproducible. Second method was specifically designed for quantitative assessment of 3D models of biological tubular systems and was practically tested on a mouse model of Alagille syndrome.
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Development of a device and methodology for Laser-Induced Breakdown Spectroscopy (LIBS)
Képeš, Erik ; Ferus,, Martin (oponent) ; Lohninger, Hans (oponent) ; Kaiser, Jozef (vedoucí práce)
This work deals with the transfer of analysis models across various laser-induced breakdown spectroscopy (LIBS) systems and the comparison of LIBS measurements obtained on distinct systems. Both the LIBS instrumentation and the data processing applied to LIBS data are highly flexible. Unfortunately, due to these flexibilities, results obtained on one LIBS system are rarely directly comparable to results obtained by a different system. This is further complicated by the various, often unknown, impact of the wide range of data processing algorithms on the LIBS data. Consequently, analysis models are generally system (and parameter) specific. The transfer of analysis models across various systems would result in the significant enhancement of the analytical capabilities of LIBS and in moderate cost reductions in industrial LIBS applications. The work studies the impact of various data collection strategies on LIBS data. Moreover, the work investigates the transformation of the acquired LIBS data through data processing. Lastly, the work addresses the transfer of analysis models across various LIBS systems.
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Enhancement of laser-induced plasma signal using nanoparticles
Salajková, Zita ; Galbács, Gábor (oponent) ; Hidalgo, Montserrat (oponent) ; Kaiser, Jozef (vedoucí práce)
Analytical techniques based on Laser ablation (LA), such as LIBS and LA-ICP-MS, are capable of rapid chemical analysis directly on the sample surface. Recently, the coupling between nanoparticles and light has been considered as a way to improve these techniques' performance. Nanoparticles coupling with laser can strongly enhance the near-field around them. When the nanoparticles are deposited on the surface to be analyzed by methods based on LA, the strong field created by the coupling between nanoparticles and laser may change the LA processes influencing the properties of laser-induced plasma. It has been shown that the presence of NPs during LA lowers the ablation threshold, enhances the signal and changes the properties of aerosol particles. The applications on Nanoparticle Enhanced LIBS (NELIBS) have found a place, where conventional LIBS have some difficulties, e.g., analysis of samples where damages are undesirable, analysis of solution at sub ppm level by employing micro-liter volumes etc. This thesis completely describes the phenomena behind nanoparticle enhanced LA, based on comprehensive experimental work and physical theory. Further, with the understanding of the fundamental principles, two new applications were developed. Firstly, NELIBS is used as an advance technique for metallic ions detection in amyloid fibrils, an advanced bio-material suitable for water purification. Secondly, NELIBS is introduced as a new method for nanoparticle protein corona sensing extending the classical use of NELIBS from the elemental analysis to the use as a sensing tool.
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Zhodnocení finanční situace podniku a návrhy na její zlepšení
Kaiser, Jakub ; Skoupilová, Yveta (oponent) ; Poláček, Tomáš (vedoucí práce)
Tato bakalářská práce je zaměřena na zhodnocení finanční situace firmy COMET OBALY s.r.o. v letech 2015-2019 metodami finanční analýzy. Práce se dělí na tři části. První část je zaměřená na teorii a jsou v ní popisovány definice pojmů a metod. Druhá část se zabývá finanční analýzou současného stavu vybrané společnosti. Poslední část se zaměřuje na návrhy pro zlepšení finanční situace daného podniku.
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Research and development of a technology of hard anodization of nonferrous alloys
Remešová, Michaela ; Kudláček,, Jan (oponent) ; Vidal, Salvador Pané (oponent) ; Kaiser, Jozef (vedoucí práce)
The thesis is focused on the research and development of the technological process for the preparation of hard anodic coatings on three different non-ferrous materials, namely (i) aluminium alloy (AA1050), (ii) pure magnesium (99.9% Mg), and (iii) zinc alloy (ZnTi2). Suitable combinations of anodizing conditions (voltage, current density, temperature and composition of the electrolyte, etc.) can produce anodic coatings with different properties. The effect of pre-treatment and anodizing conditions on the appearance, morphology, thickness and hardness of the produced anodic coatings was demonstrated in the present thesis. In order to increase tribological properties and hardness, the anodic coatings were directly doped with Al2O3 or with a mixture of Al2O3/PTFE particles during the anodizing process. The theoretical part describes the basic principles of anodization, the methods used in industry and the technological process. The experimental part is divided into three basic parts. The first part is devoted to anodizing of aluminium alloy. The second part is focused on anodizing of pure magnesium, and the last part is focused on anodizing of zinc alloy, which has not been researched as thoroughly as anodizing of aluminium.
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Design of pulse generator for laser spectroscopy
Cebo, Patrik ; Žalud, Luděk (oponent) ; Kaiser, Jozef (vedoucí práce)
This diploma thesis deals with the design of a precise multi-channel pulse generator for the synchronization of laser-induced breakdown spectroscopy (LIBS) instrumentation. The thesis reflects current state-of-the-art solutions in communication and trends in the field of laser spectroscopy. Moreover, the device is based on the modern implementation of embedded devices using C and C++ programming languages using the Ethernet for communication. The communication with the control software is provided via the SDD protocol; designed at CEITEC BUT. Finally, the data of the SDD protocol are sent by the hypertext transfer protocol (HTTP) protocol in native file format (JSON). This thesis brings the synchronization of the 10 devices by precision timing.
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Processing of aerogel coatings on bulk materials substrates
Torres Rodríguez, Jorge Alberto ; Torre, Sebastián Díaz de la (oponent) ; Pinkas, Jiří (oponent) ; Kaiser, Jozef (vedoucí práce)
In this thesis, a systematic study of the synthesis and processing of advanced thermal-stable aerogels for potential high-temperature applications was carried out. The first part of this work details the synthetic implications to prepare an aerogel and its applications along with a description of the sol-gel coatings deposition techniques. The experimental procedure is divided into three sections. The first one shows the followed synthetic protocols to prepare ZrO2, YSZ, Ln2Zr2O7 (Ln = La3+, Nd3+, Gd3+, and Dy3+) aerogels, and Ln2Zr2O7 powders and xerogels. Then is described the used deposition method to prepare aerogel coatings on metallic substrates. Followed this, the characterization techniques are specified. It was found that the amount of water and nitric acid plays a determinant role to obtain suitable wet gels to transform into aerogels. Upon calcination at 500 °C, the ZrO2 and YSZ aerogels have a high surface area up to 114 m2 g-1, however, at 1000 °C, complete densification occurs losing all their porous structure. In comparison with the ZrO2 and YSZ, the Ln2Zr2O7 aerogels are thermally more stable since preserves their porosity at elevated calcination (1000 °C) with values >160 m2 g-1. In the studied temperature range, the ZrO2 aerogel experiment a complex tetragonal monoclinic phase transition driven by the crystallite size, while the YSZ is constituted by single-tetragonal phase. The phase composition of the rare-earth zirconates is highly dependent on the synthesis method; all the Ln2Zr2O7 materials are pyrochlore or fluorite crystalline phases. The direct casting of the aerogel on the metallic substrate yield completely broken coatings due to effect of shrinkage, while the slurry dip-coating allowed to fabricate homogeneous, thick, and coarse aerogel coatings. These coatings do not present phase changes and remain highly porous after different heat treatments.
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X-ray nano computed tomography of structured polymeric biomaterials
Kalasová, Dominika ; Oberta,, Peter (oponent) ; Kataja, Markku (oponent) ; Kaiser, Jozef (vedoucí práce)
This thesis is focused on an advanced imaging method X-ray computed nanotomography (CT). This non-destructive technique is used for the research of various biomaterials in tissue engineering and material science in general (scaffolds, polymers, ceramics, composites, etc.). Visualisation and quantification in 3D are advantageous in multidisciplinary approach usually applied in these fields. The objective of the thesis is divided into two topics. The first topic is about optimisation of the measurement procedure for various soft materials by CT with the laboratory X-ray sources. Mostly, the phase contrast propagation-based CT imaging (PBI) is involved here. This work theoretically describes the PBI and demonstrates this phenomenon via several sets of measurements. The necessary post-processing of PBI data is implemented and evaluated based on data quality enhancement. The second topic shows specific applications of CT in material engineering. Several studies with different CT devices show a few examples of possible applications and image processing options. Examples of correlation of CT with other complementary techniques show how CT can be applied in a multidisciplinary approach to solving complex scientific problems.
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LIBS assessment of spatial photon-upconversion nanoparticle distribution in model plants (R. sativus and L. minor)
Modlitbová, P. ; Novotný, K. ; Hlaváček, Antonín ; Pořízka, P. ; Kaiser, J.
In the present study, radish (Raphanus sativus L.) and common duckweed (Lemna minor L.) were treated with an aqueous dispersion of carboxylated silica-coated photon-upconversion nanoparticles containing rare-earth elements (Y, Yb, and Er). The total content of rare earths and their bioaccumulation factors were determined in the root, hypocotyl, and leaves of R. sativus after 72 hours, and in L. minor fronds after 168 hours. In R. sativus, translocation factors were determined as the ratio of rare earths content in hypocotyl versus roots and in leaves versus hypocotyl. The lengths of the root and hypocotyl in R. sativus, as well as the frond area in L. minor were monitored as toxicity end points. To distinguish rare-earth bioaccumulation patterns, two-dimensional maps of elemental distribution in the whole R. sativus plant and in L. minor fronds were obtained by using laser-induced breakdown spectroscopy with a lateral resolution of 100 μm. Obtained results revealed that the tested nanoparticles became adsorbed on L. minor fronds and R. sativus roots, and got transferred from roots through the hypocotyl into leaves in R. sativus. Our results show that bioaccumulation patterns and spatial distribution of rare earths in nanoparticle-treated plants differ from those of positive control (the mixture of YCl3, YbCl3, and ErCl3).
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