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Capsule-free Hot Isostatic Pressing of transparent structural and functional ceramic materials
Krupa, Filip ; Drdlík, Daniel (referee) ; Maca, Karel (advisor)
The presented work focused on evaluating the suitability of several types of cubic zirconia powders for preparing suspension with a high solid content (over 40 vol.%). The suspensions were doped with TiO2 nanopowder (0,1 – 0,5 at. %). The influence of the shaping method (casting the suspension and drying the suspension by spray drying, followed by shaping through pressinng) and subsequent pre-sintering to the closed porosity stage was investigated, focusing on comparing two sintering regimes (long – 1300 °C/120 min and short – 1560 °C/2 min). The microstructure of both the pre-sintered samples and the samples after hot isostatic pressing was then observed using an electron microscope. The presented work assessed the influence of TiO2 on relative density, average grain size, and pore size, as well as the optimal amount of TiO2 to achieve maximum photoluminescent properties.
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Solid form of liposomal systems for inhalation
Fardová, Lucie ; Kalina, Michal (referee) ; Mravec, Filip (advisor)
This thesis deals with the preparation of solid liposomal systems for inhalation delivery. Liposomal systems were prepared by rehydration of a phospholipid film from dipalmitoylphosphatidylcholine. A sucrose solution used for film rehydration served as a protectant during spray drying. Additional liposome samples contained cholesterol, phosphatidic acid, or polyethylene glycol for better stabilization. The prepared liposome solutions were examined using scanning transmission electron microscopy, dynamic light scattering, and electrophoretic light scattering methods. Dried powders were measured using infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and determination of particle aerodynamic size. The results demonstrate the successful preparation of all liposomal systems, their drying into powder form, and subsequent reconstruction after rehydration with water or buffer. Based on the observed properties, liposomes with polyethylene glycol appeared to be the most suitable.
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Rozprašovací sušení vícesložkových suspenzí s rozdílnou hustotou
Brožek, Vlastimil ; Domlátil, J.
This article deals with the issues faced during the preparation of multi-component powders having largely different densities in spray dryers. On a model system, TiO2 – W with densities TiO2 ρ= 4,23 g/cm3 and W ρ= 19,3 g/cm3 , processed in an industrial facility with a 100kg/h capacity using a temporary binder carboxyl-methyl-cellulose, the dependence of composition on the size and distribution of primary particles. Compositional changes and inhomogeneous component distribution takes place due to sedimentation in the feed line between the suspension mixer and drying nozzle. The suspension density and the shape factor that influences the transport velocities of the starting powders, also play a role. The overall effect is assessed by analysis of the properties of the final product, plasma sprayed TiO2-W cermet.
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