This thesis inquire into experimental decomposition of freon R-22 (CHClF2 - chlorodifluorometan) for different process conditions, by the help of pilot experimental unit in heavy laboratories DEPARTMENT of process and enviromental engineering Brno. This unit can decomposition waste gas, as the case may be combustion gas by the thermic oxidation or catalytic oxidation. Ground was in theoretical research, in which had been executed decomposition of freon R-22 in laboratory. In terms of experimental work were to be execution states for decomposition of freon R-22, next will be decomposition of freon R-22 by catalytic oxidation on catalyst Pt/Al2O3 and consequently this experiment will be analyse. Part of this thesis is exploration of facts basic way to decomposition of freon R-22, accounting of experimental unit and discussion of results.

The work was focused on the preparation of layered ceramic materials and their characterizations. The direct measurment of weight deposite for enhanced description of one component system was studied within this work. The kinetics of electrophoretic deposition obtained from theoretical calculation and from experimental values were confronted. It was prepared a lot of depositions for described kinetic of electrophoretic deposition with applied constant currents. The relative density and porosity were determined on the annealled and sintered bodies. The hardness measurments were performed on sintered bodies and then resulted values were confronted with the used currents. A ceramic composite based on Al2O3 and ZrO2 was prepared by using of precision describtion of electrophoretic deposition kinetic.

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his thesis deals with preparation of transparent ceramic sheets made out of sub-µm alumina powder. Green bodies are prepared by ultraviolet (UV) curing of UV curable resin containing ceramic powder followed by debinding of organic parts at elevated temperature. High relative density of green bodies is essential for reduction of shrinkage during subsequent sintering process. Therefore high solids loading dispersions containing > 57 vol% ceramic particles are used. To reach transparent behaviour, porosity within the sheets must be reduced completely. Therefore hot isostatic pressing (HIP) is used as a final operation. Finally, light transmission and hardness measurements are presented. Possibilities of making high resolution microstructures using maskless lithography and some suggestions for use of the UV curing technique for production of complex-shaped 3D structures are briefly mentioned.

Composite materials with laminated structure provide advantages which are utilised during component design. Low density, temperature and chemical stability are the profitable properties predetermining application of ceramic laminates. The main obstacle for wide spread of ceramic materials is their inherent brittleness. Therefore, in this thesis, the crack propagation in ceramics laminates has been extensively studied. Laminated structures with various volume fractions of components (alumina and zirconia) were prepared by electrophoretic deposition. Evaluation of crack propagation through the interface and determination of basic mechanical properties was conducted on the basis of extensive literature search. Crack deflection originated in both presence of internal stresses and differences in elastic modulus during the crack interface passing was monitored. A special type of specimen geometry was employed with the aim to set arbitrary angle between crack and interface. It was experimentally found that the degree of crack deflection is dependent on entering angle and volume fraction of components. Higher crack deflection was already found in the bulk of the test piece comparing to the test piece surface. The 3D fracture surface reconstruction generated using laser confocal microscopy was used in this detailed crack propagation study. Further basic elastic and strength characteristics of laminates were determined and compared to those obtained from monolithic materials. The validity of the mix rule for elastic characteristics was confirmed by comparing of elastics modulus. The most reliable method for elastic modulus determination was marked the dynamic resonance method due to low scatter and consistency in measurement. The flexural strength of all laminates tends to be close to the flexural strength of the weakest component. Therefore the mix rule is not applicable for flexural strength estimation on the contrary of elastic characteristics. The change of component volume fraction leads only to change of flexural strength scatter. Thanks to gained knowledge about crack propagation and basic characteristic determination will be possible to design ceramic laminates more efficiently for given needs of application.

In the diploma thesis, an overview of the existing literature focused on the thermoplastic co-extrusion method was worked out and based on the findings, extrusion of the monolayer and homogenous bodies from ZrO2, Al2O3, ZTA a ATZ was studied. For thermoplastic extrusion the capillary rheometer was modified and the nozzle was designed and fabricated. Applying the co-extrusion method, homogenous ceramic rods and monolayer rods in structure core/layer: ZrO2/Al2O3, ZrO2/ATZ and ZTA/Al2O3 were fabricated. In monolayer rods, the interface quality and defects that originate during preparation were evaluated. Technological parameters and properties of homogenous rods were used to rate the structure and defects in monolayer rods. Monolayer rods ZrO2/ATZ and ZTA/Al2O3 with 2.5 mm diameter and 45 mm length (containing small defects) were prepared by thermoplastic co-extrusion.

The crater wear of alumina coated WC-Co cutting tools is thought to be influenced by the chemical reactions between the coating and the workpiece material. Three different crystal orientations ((001), (012), and (100) of alpha alumina CVD coatings are examined in combination with four workpiece materials of steel to establish what reactions are present, and the extent of diffusion. The alumina coatings and workpiece materials were pressed together as diffusion couples and heat treated at 1250- 1300°C for 10-20hours. It was fond that the types of inclusions present in the workpiece were more impactful on the chemical wear of the coating than the crystal orientation of the coating. EDS measurements show significant amounts of W and Co on the surface of the coatings and on the steel surfaces after heat treatment. This is thought to be connected to the migration of Co through the coating in cooling cracks and other impurities. In the surface of the coating, areas of solidified Co-rich structure have been found, implying that Co has formed an alloy with Fe, C, Al, and W with sufficiently low melting temperature to partially melt during the heat treatment. This has been confirmed as possible by simulations in Thermo-calc. Turning tests and scratch tests were made with the same combinations of coatings and workpiece material and show differences in adhesion of workpiece material on the different coating orientations. The 100-orientation has been found to have the most adhered workpiece material, the reason for this being its higher surface roughness. Ultimately no noticeable differences in chemical reactivity between the coating crystal orientations was found. The Co diffusion though the coating occurred for all the coating orientations and further experiments in turning with the different workpiece materials are required to determine the effect of Ca-rich inclusions on the magnitude of chemical wear. / <p>Handledare på företag:</p><p>Susanne Norgren </p><p>Doc.  Ph.D,  Group Expert Materials Design</p>

In China, the textile industry is important for the economy. However, the industry contributes to emissions of organic material and other pollutants. This affects the environment and the quality of life for people and animals. All over the world, water scarcity is becoming an increasing problem, which is why the UN has water purification as one of the goals for sustainable development. To achieve these goals and the regulations in countries, wastewater is purified in water treatment plants before it is discharged. One of the methods that can be used to purify water is catalytic ozonation, an oxidation process in which ozone is used as an oxidant to break down organic material. Catalysts, usually metal oxides, are used to increase the selectivity and the reaction rate. However, this is a relatively unexplored area in water purification and several details within the process are unknown, such as optimal conditions for various catalysts and the exact reaction mechanism. In this work, catalytic ozonation treatment with the metal oxide MnOx-CeOx/γ-Al2O3 has been investigated. Firstly, a literature study was carried out to find earlier research in the field. Then experiments were conducted, varying four different factors and the impact these factors had on the catalytic ozonation was analyzed. The factors examined were contact time, ozone dosage, gas flow and amount of catalyst. All factors had three different levels. COD and UV254 were analyzed to find the conditions that gave the highest reduction of organic matter. The highest reduction of COD was 67 % which gave a COD concentration of 23 mg/L and UV254 90 %. Since the regulations on COD emissions in China are 30 mg/L, the catalytic ozonation gave a satisfying result. The result showed that the highest yield was achieved at the highest level for contact time (40 min), ozone dosage (0.3 mg/L) and amount of catalyst (100 % filled reactor), but the second highest for the gas flow (0.3 L/min). However, the contact time was calculated to be the only significant factor for reducing COD in water. The other factors did not have a significant effect on the reduction of COD or UV254. Furthermore, the conditions that were calculated to give the greatest reduction were used to analyse the reduction of impurities in the wastewater with three dimensional fluorescence. Three dimensional fluorescence showed that the wastewater contained organic compounds, mainly aromatic proteins, soluble microbial by-products and humic acids. All of these compounds were reduced during the catalytic ozonation with MnOx-CeOx/ γ-Al2O3. The residual amount of ozone was analyzed in effluent gas flow was measured with different incoming gas flows. The residual ozone after the ozone treatment was approximately 45 % of the ingoing gas flow. / I Kina är textilindustrin viktig för ekonomin. Dock bidrar industrin till utsläpp av organiskt material och andra föroreningar. Detta påverkar miljön och livskvalitén för människor och djur. Världen över börjar vattenbrist bli ett allt större problem, varför FN har med vattenrening som ett av målen för hållbar utveckling. För att nå dessa mål och de regleringar som gäller renas avloppsvatten i vattenreningsanläggningar innan det släpps ut. En av de metoder som kan användas för att rena vattnet är katalytisk ozonbehandling, vilket är en oxidationsprocess där ozon används som oxidationsmedel för att bryta ned organiskt material. För att öka selektiviteten och reaktionshastigheten används katalysatorer, vanligen metalloxider. Detta är dock ett relativt outforskat område inom vattenrening och flera detaljer inom processen är okända, såsom optimala betingelser och reaktionsmekanismen. I detta arbete har därför katalytisk ozonbehandling med metalloxiden MnOx-CeOx/ γ-Al2O3 undersökts. Först utfördes en litteraturstudie för att ta fram tidigare forskning inom området. Därefter utfördes experiment där fyra olika faktorers påverkan på den katalytiska ozonbehandlingen analyserades. De faktorer som undersöktes var uppehållstid, ozondosering, gasflöde och mängd katalysator. Samtliga faktorer hade tre olika nivåer. De faktorer som analyserades var COD och UV254 för att hitta de förhållanden som gav högst reduktion av organiskt material. Den högsta reduktionen av COD var 67 %, vilket gav en COD-koncentration på 23 mg/L och UV254 reducerades upp till 90 %. Eftersom gränsen på COD-utsläpp i Kina är 30 mg / L gav den katalytiska ozonbehandlingen ett tillfredsställande resultat. Det nivåer som gav bäst utbyte var de högsta för uppehållstiden (40 min), ozondoseringen (0.3 mg/L) och mängden katalysator (100 % fylld reaktor), men den näst högsta för gasflödet (0.3 L/min). Den enda faktorn som hade en signifikant påverkan på reduktionen av organiskt material var dock uppehållstiden. Övriga faktorer hade ingen signifikant påverkan på varken reduktionen av COD eller UV254. Vidare användes ändå de nivåer som beräknats ge störst reduktion av organiskt material för att analysera reduktionen av föroreningar i avloppsvattnet med tredimensionell fluorescens. Avloppsvattnet innehåller organiskt material som aromatiska proteiner, lösliga mikrobiella biprodukter och humussyror och dessa föroreningar reducerades vid katalytiska ozonbehandlingen med MnOx-CeOx/ γ-Al2O3. Dessutom analyserades resterande mängd ozon i utgående gasflöde vid olika storlek på ingående gasflöde. Resterande mängd ozon efter ozonbehandlingen var ungefär 45 % av ingående mängd.

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