This theses focused on the topic of silence and sound is divided in two section. Theoretical part contains information and knowledge from fields of physical phenomena, theory opf colors, psychology and theory of art (mainly based on work of W. Kandinski), that establish theorethical baseline for practical part, in this case realized graphic intent. Realization of practical part is an authorial construction of plastic interpretation of silence and sound. It tries to graphically express these two constructs with combination of pottery and glass in colorful compositions.

The master{\crq}s thesis is divided into three parts. The introductory part is concerned with the turtle from a professional viewpoint. The historical development and symbolism of this creature are dealt with, as well as palaeontological findings and relevant bits of interesting information. The following chapters are primarily practical. This practical work on the ceramic sculpture, though, is also based on the study of relevant literature. The third part provides a photodocumentation to the text. It features the final product as well as the process of its creation.

The main aim of my master thesis is to describe the development of painted folk decor on ceramics since the arrival of Anabaptism in the Czech Republic. Selected Moravia workshops are used to track the decor development. Another goal of this thesis is to find out whether workshops that produce ceramics and subsequently paint it in the traditional way exit even today. Next part of my thesis is devoted to selected Czech workshops that produce painted ceramics. A presentation consisting of photos is included as well as a literature research.

Implementation of the topic of the thesis is based on an interpretation of the question of individuals´ identification in the society, using particular materials. This topic has to be perceived, reflected and evaluated subjectively. The method of autoreflexion led the author, while searching his own way of expression, to non-traditional materials and a specific way of working with them. Theoretical part of the thesis explains his statements, sources of inspiration and possibilities of employing author´s experiences in the process of teaching.

The present thesis examines two ceramic assemblages from the villa baths at Pollena Trocchia, Italy. The private bath complex was likely part of the Roman villa built at the beginning of the 2nd century AD and buried under the volcanoclastic debris of the AD 472 eruption which provided an important terminus ante quem. The previous studies demonstrated that in the 5th century AD the bath complex became a pottery dump and cemetery. Nevertheless, a different picture was drawn from the excavation of the underground cistern in the north-western part of the baths. In order to better understand the purpose of the cistern prior to the eruption, which sealed most of the site, the pottery assemblage from the cistern was compared to the assemblage from one of the bathrooms identified as the laconicum. In fact, the cistern uncovered rather low number of individuals compared to the rest of the baths and the ratio of attested pottery classes was limited. While the African imports were almost absent, there was a great number of local products. Most of the shapes consisted of locally produced jugs of big volume, which could be associated with the water-supply system. When possible, the individuals were dated to the second half of the 5th century. Therefore, it is likely that the cistern was still in use a long...

The work is focused on evaluation of factors influencing behaviour of interface in low toughness ceramic materials reinforced with fibres. The main aim was to characterise processing effects influencing the quality of fibre-matrix interface, with respect to final behaviour of composites at various loading type. The partial goal was to map the possibility of influencing the composite material by choice of matrix material, eventually by change of its processing, leading to change of interfacial properties without need of modification of reinforcement surface. The materials used in studied composites as a matrix were based on thermal transformation of polymer precursors, thus, the resulting materials were characterised in partially as well as in fully pyrolyzed state. Behaviour of interface in cpomposite materials was first evaluated from the global behaviour (i.e., change of mechanical properties) and in chosen representative composites also from the point of local changes in close surrounding of the interface (i.e., microstructure, chemical processes, fracture-mechanic processes, etc.) due to thermal exposition. In experiment were used particularly composite materials prepared by pyrolysis of polysiloxane resins reinforced by basalt fibres or Nextel™720 fibres. With respect to thermal resistance of the reinforcement, the basalt reinforced composites contained only partially pyrolyzed matrix (i.e., to temperature of 800°C), and in composites with Nextel™720 reinforcement was the matrix in form of fully pyrolyzed polymer into ceramic (SiOC). At partial pyrolysis of polysiloxane resin occurs rapid change of behaviour at temperature of 600°C. It was demonstrated, that around this temperature the formed interface with basalt fibre exhibits optimum adhesion/strength, allowing to reach sufficient level of composite strength at acceptable fracture toughness. Above temperature of 750°C occur significant difusion processes in the area of the interface and formation of new crystalline phases in the fibre, what deteriorates the fibre strength, and on the contrary, strengthen the interface cohesion, what leads to degradation of properties of the whole composite. At composite materials determined for high temperatures, reinforced by Nextel™720 fibres, was detected significant resistivity against oxidation caused especially by fully pyrolyzed matrix. As similarly important factor was observed the formation of mullite interphase in surface area of the fibre. Volume changes caused by formation of the interphase, difusional transport of the matter and thermal exposition led to formation of thermally and stress-induced micro-cracks, weakening interfacial surrounding in matrix as well as in fibre. This mechanism in contrast to amplifying chemical bond between fibre and matrix led to preserving of the composite properties also at high temperatures up to 1500°C. The work also dealed with effects of loading rate, where in contrast to static loading were observed different failure mechanisms. Realized research led to description and explanation of the influence of the fibre-matrix interface by change of matrix material processing parameters, which allow processing of economically advantageous and thermally stable composite.

<p><strong>Apstrakt je obrađen tehnologijama za optičko prepoznavanje teksta (OCR).</strong></p><p>Dobro je poznato da se žilavost keramičkih matrica znatno može povećati sa cirkonia česticama iz razloga &scaron;to se transformacijom tetragonalne u monokliničnu fazu cirkonie znatna količina energije može apsorbovati, a koja bi inače bila pukotini na raspolaganju za njeno napredovanje.<br />U ovom radu je primenom različitih varijanti sol-gel procesiranja menjana priroda i skala veličine polaznih alumina i cirkonia čestica u cilju dizajniranja mikrostrukture alumina-cirkonia kompozita. Ukazano je na postojanje interakcije između cirkonie i alumine, &scaron;to je i pored &scaron;irokog proučavanja alumina-cirkonia kompozita skoro nepoznata pojava. Pokazano je takođe da stepen interakcije zavisi od prirode i veličine polaznih čestica, pri čemu je najveći kod alkoksidnih matričnih kompozita sa cirkoniom dodanom u obliku veoma finih sol čestica ili cirkonjjumovih soli (na primer cirkoniju oksihlorid), a najmanji kod čestičnih matričnih kompozita kod kojih su kori&scaron;čene guste čestice (alumine-cirkonie).<br />Potvrđeno je da stepe interakcije određuje mikrostrukturni razvoj kompozita u toku zagrevanja. Uticaj interakcije na mikrostrukturni razvoj alumina-cirkonia kompozita je praćen različitim metodama karakterizacije (merenje gustine, IR spektroskopija, rentgenska difrakcija, diferencijalno termijska analiza i skening elektronska mikroskopija). Posle finalnog sinterovanja i bez toplog presovanja su dostignute gustine bliske teorijskim, a postignute mehaničke osobine merene su tvrdoća i žilavost) su razmatrane u funkciji mikorstrukturnih parametara. Utvrđeno je da je dominantan mehanizam povećanja žilavosti naponom indukovano povećanje žilavosti, a maksimalno postignuta vrednost odnosa povećanja žilavosti prema žilavosti matrice iznosi K_s/K_o = 0.69 (&scaron;to odgovara vrednosti kritičnog faktora intenziteta napona od K_c=5.4 MPa m^1/2). Na kraju treba jo&scaron; istaći da eksperimentalno dobijene vrednosti žilavosti dobro fituju izvedenu zavisnost doprinosa transformacionog povećanja žilavosti od veličine tetragonalni cirkonia čestica.</p> / <p><strong>Abstract was processed by technology for Optical character recognition (OCR).</strong></p><p>It is already known that fracture toughness of the ceramic matrices could be increased by dispersing of zirconia particles. The role of zirconia is in the absorption of a substantial amount of energy, which could be consumed by crack advansing, with the transformation from tetragonal to monoclinic simetry.<br />In the presented study the microstructure of the alumina-zirconia composites were designed by changing the nature and the size of original alumina and zirconia panicles, by using a different types of the sol-gel processing methods. It is pointed out on the mutual interaction between zirconia and alumina, which is almost unknown phenomena inspite of very intensive investigation of the alumina-zirconia composite system. The mutual interaction depends on the nature and size of the original particles. The largest interaction exists in alkoxide matrix composites with zirconia added in a form of very fine so! particles or zirconijum-salts (zirconium-oxychloride), and the smallest in the particulate matrix composites with dense panicles (alumina or zirconia). It is confirmed that interaction between zirconia and alumina determine the microstructure development of the heat treated composite samples. The influence of the interaction on the microstructure development was characterised by different method: density measurement, IR spectroscopy. X-ray diffraction, differential thermal analysis and scanning electron microscopy. After final sintering without hot pressing the density reach very high values (in some case &gt;99 % theoretical density). Mechanical properties (hardnes and fracture toughness) were studied in the function of the microstructural parameters. It was shown that the stress induced transformation toughening is a dominant mechanism in the sol-gel processed composites (with zirconia partcles less than critical size)., and the maximal value of the AKc/Ko = 0.69 corresponds to the fracture toughness of Kc = 5.4 MPa m1/2. Experimental fracture toughness data fit the analytically derived functional dependent between fracture toughness and zirconia particle sizes.</p>

The present thesis focuses on the preparation of tetragonal zirconia doped with yttria oxide, ceric dioxide, and magnesium oxide. In its theoretical part the thesis covers the characteristics of doped ceramics, the possible methods of powders preparation and of their further processing. The experimental part describes the precipitation synthesis of zirconia in base environment and further processing for ceramics. Also studied were the influences of dopant and of the processing technique used on the phase composition and microstructure of the resulting ceramics. To describe the powder structure, the thermal, dilatometric, surface area, and x-ray analyses were performed; as well as both the scanning and transmission electron microscopy employed. Dry processed ceramics showed the average grain size of 87–94 nm and the relative density in the range of 84,0–99,3 %. In comparison, the ceramics produced of hydrothermally synthesised powders proved the average grain size of 75–85 nm and the relative density between 92,7-99,9 %. As the next step, samples were subjected to low-temperature degradation for the time of 5 and 15 hours. Samples consisting of pure tetragonal ZrO2 were resistant to 5 and 15 hours of low-temperature degradation at 180 °C.

The aim of this diploma thesis is experimental verification of the influence of ceramics composition on the manipulation strength of the cores in the Shaw method. The work deals mainly with influence of the amount of acid in the composition of the binding fluid on the handling strength of the cores and the strength of the cores after annealing. The thesis further examines the possibility of increasing the handling strength of the cores by adding phosphoric acid to the binding fluid.

The work is focused on evaluation of factors influencing behaviour of interface in low toughness ceramic materials reinforced with fibres. The main aim was to characterise processing effects influencing the quality of fibre-matrix interface, with respect to final behaviour of composites at various loading type. The partial goal was to map the possibility of influencing the composite material by choice of matrix material, eventually by change of its processing, leading to change of interfacial properties without need of modification of reinforcement surface. The materials used in studied composites as a matrix were based on thermal transformation of polymer precursors, thus, the resulting materials were characterised in partially as well as in fully pyrolyzed state. Behaviour of interface in cpomposite materials was first evaluated from the global behaviour (i.e., change of mechanical properties) and in chosen representative composites also from the point of local changes in close surrounding of the interface (i.e., microstructure, chemical processes, fracture-mechanic processes, etc.) due to thermal exposition. In experiment were used particularly composite materials prepared by pyrolysis of polysiloxane resins reinforced by basalt fibres or Nextel™720 fibres. With respect to thermal resistance of the reinforcement, the basalt reinforced composites contained only partially pyrolyzed matrix (i.e., to temperature of 800°C), and in composites with Nextel™720 reinforcement was the matrix in form of fully pyrolyzed polymer into ceramic (SiOC). At partial pyrolysis of polysiloxane resin occurs rapid change of behaviour at temperature of 600°C. It was demonstrated, that around this temperature the formed interface with basalt fibre exhibits optimum adhesion/strength, allowing to reach sufficient level of composite strength at acceptable fracture toughness. Above temperature of 750°C occur significant difusion processes in the area of the interface and formation of new crystalline phases in the fibre, what deteriorates the fibre strength, and on the contrary, strengthen the interface cohesion, what leads to degradation of properties of the whole composite. At composite materials determined for high temperatures, reinforced by Nextel™720 fibres, was detected significant resistivity against oxidation caused especially by fully pyrolyzed matrix. As similarly important factor was observed the formation of mullite interphase in surface area of the fibre. Volume changes caused by formation of the interphase, difusional transport of the matter and thermal exposition led to formation of thermally and stress-induced micro-cracks, weakening interfacial surrounding in matrix as well as in fibre. This mechanism in contrast to amplifying chemical bond between fibre and matrix led to preserving of the composite properties also at high temperatures up to 1500°C. The work also dealed with effects of loading rate, where in contrast to static loading were observed different failure mechanisms. Realized research led to description and explanation of the influence of the fibre-matrix interface by change of matrix material processing parameters, which allow processing of economically advantageous and thermally stable composite.