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Study of the synthesis and structure of ceramic perovskite materials for energy applications
Strejček, Josef ; Bartoníčková, Eva (referee) ; Cihlář, Jaroslav (advisor)
Method, so called “glycin- nitrate process”, combined with high temperature solid state reaction, of preparation multi- component ceramic perovskite materials was studied. Two types of perovskite systems were prepared by this method. Firs one, based on LaNiO3 doped by calcium and aluminium and second one, based on SmFeO3 doped by calcium and nickel or cobalt. This method made possible preparation of one phase perovskite or perovskites with few percent of nickel in form of oxide. In systems containing both nickel and calcium another phases rich in calcium and nickel appeared.
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Quality of hydrophobic domains in polyelectrolyte-surfactant system
Holínková, Petra ; Vala, Martin (referee) ; Mravec, Filip (advisor)
In this bachelor thesis were studied the photophysical properties of four fluorescent probes depending on the viscosity of their surroundings by the fluorescence spectroscopy. For probes DPH, DPB a perylene was determinated dependence of fluorescence anisotropy and for P3P dependence of ratio excimer/monomer on the viscosity of the sample. Anisotropy probes DPH and perylene were also used to study interaction between hyaluronan and cationic surfactant CTAB (concentration below CMC) in aqueous solution and 0,15 M NaCl. Information about forming hydrophobic domains were obtained by measurement of fluorescence intensity and anisotropy depending on the concentration of CTAB in the sample. It was found that in an aqueuos solution, after the initial addition of CTAB to hyaluronan formed small hydrophobic domains linked to chain of hyaluronan. Increasing concentration of CTAB leads to the formation of gel and phase separation. After addition of NaCl leads to reorganization of this system and probably the formation of free micelles in the solution with higher concentration of CTAB.
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Fuid bed boiler for biomass
Bytešník, Jan ; Skála, Zdeněk (advisor)
This master thesis designes the calculation of fluid boiler with specific part - the circular fluid bed. The heat is given by combustion of wood biomass. The thesis is devided into several parts. All necessary elementary results are going to be reached within these parts: an analysis of solid fuel, stechiometry calculation, discussion on output limits and the environmental point of view, definition of elemental heat losses and general heat efficiency, calculation and design of a combustion part and its heat loads and calculation of enthalpies with different ash concentrations. All these phases get to a successful design of the fluid boiler heat balance and sizes of heat-flow surfaces. The composition of the boiler shows the added drawing.
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Ab initio studie Lavesových fází v systémech Fe-Cr, Fe-Mo a Fe-Ta
Houserová, Jana ; Šob, Mojmír
Binary systems Fe-Cr, Fe-Mo and Fe-Ta can be found in many kinds of steels where the Laves-phase can be considered as a potential candidate for strengthening provided size and distribution of the particles are within certain limits. We performed electronic structure calculations to study the thermodynamic and structural properties of the C14 Laves phase with various compositions. In the frame of the thermodynamic study, we have evaluated the total energies of formation of Laves phase structure with different occupations of sublattices (Fe2Fe, Fe2X, X2Fe, X2X, where X stands for Cr, Mo and Ta) with respect to the Standard Element Reference (SER) states. These energies of formation are of great importance for prediction of stability of studied configurations.
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Aroma profile of cheese analogues
Součková, Šárka ; Pšenáková, Ivana (referee) ; Vítová, Eva (advisor)
This Bachelor’s thesis deals with the issue of processed cheese analogues. It will explain what they are, their chemical composition and properties. The aim is to examine a number of cheese analogue samples with added various types of vegetable fats and identify and quantify the volatile aroma active substances present. Aroma compounds were isolated from samples using the Solid Phase Microextraction (SPME), a fiber with polar stationary phase (CARTM/PDMS) was used and the captured substances were then determined by gas chromatography. The evaluated cheese analogues varied in the type of the contained fat. In total 27 aroma active compounds in different amounts were identified. Cheese analogue with sunflower oil contained the most compounds (24) and the smallest number of aroma substances (16) has been detected in the cheese analogue with coconut fat. The highest concentration of aromatic compounds was found in the analogue with coconut fat and lowest in the cheese analogue with palm fat. Ethanol occurred in all types of analogues in the largest concentration. In conclusion it can be argued that the various analogues varied in the type and the amount of aromatic compounds, depending on the type of fat used.
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Micro-electromembrane extraction across multiple aqueous and organic phases for selective pretreatment of raw biological samples
Kubáň, Pavel ; Boček, Petr ; Seip, K. F. ; Gjelstad, A. ; Pedersen-Bjergaard, S.
Micro-electromembrane extraction (μ-EME) across multiple aqueous and organic\nsolutions was developed for selective extractions of various analytes from untreated\nbiological samples. The novel approach requires μL volumes of samples and organic\nsolvents, which form consecutive immiscible plugs in a transparent polymeric capillary\nand the extraction process is accelerated by application of d.c. voltage. Number of the\nplugs, their composition, volume and sequence in the extraction capillary can be chosen\nspecifically for each particular application and high variability and selectivity of the\nextraction process can be achieved. In this contribution, we demonstrate suitability of\na five-phase μ-EME system for simultaneous extractions of cations and anions from\nurine and for selective extractions of basic analytes based on their acid-base strength\nfrom plasma.
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Heat and mechanical resistance of zinc coating
Horák, Karel ; Dzimko, Marián (referee) ; Černý, Michal (advisor)
The work is aimed at studying the thermal degradation of the protective zinc coating. Its large part deals with the structure of the various stages of transition and their arrangement, the main emphasis is on analysis of brittle intermetallic phases, which arise due to increased temperature. Conclusion of the work is trying to clear itself causes degradation of this protective layer.
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