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Diversity and function of pattern structures in the microworld
Hirnerová, Anna ; Škaloud, Pavel (advisor) ; Němcová, Yvonne (referee)
This thesis summarizes current knowledge of patterns and structures at various scales, with an emphasis on the use of these patterns in the microworld and also on the materials that are most often used. Patterns are applied in all areas of natural processes and human activity. There are many analogous models at different scales, but we do not know if they have the same self-organizing mechanisms. Many patterns formed by microorganisms can be prepared without their presence, on the basis of physical and chemical methods, so they are probably created under certain parameters that can be influenced by a given protist. These patterns are evolutionarily advantageous for microorganisms, because they provide them with a number of functional adaptations, mainly in connection with defense against predators and movement in the water column, which is based on the organism's life strategy. The mathematical description of the pattern is extremely important for its further research and for determining the laws that have allowed the organism to benefit from its parameters. Keywords: pattern, structure, convection, reaction - diffusion model, geometry, protist, microorganism, skeletons, shells, scales
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A Comparison of the Development of Korean Folk Song in Different Regions
Lee, Yewon ; Agopian, Vartan (advisor) ; Saláková, Magdalena (referee)
of the bachelor thesis A Comparison of the Development of Korean Folk Song in Different Regions By Yewon Lee This thesis deals with Korean folk music and basic characteristics in Korean traditional music (such as rhythms, scales, and different kinds of forms), history of Korean music from prehistoric era through modern times, and some harmonic analysis of Korean folk songs from different regions and distinct characteristics in each region. This thesis also focuses on how music from foreign country can be taught for music teachers all over the world.
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The significance of silica structures in chromist microorganisms.
Nováková, Dora ; Škaloud, Pavel (advisor) ; Němcová, Yvonne (referee)
The silica is one of the most common elements in the Earth's crust. During erosion it is released in soluble form to the environment, where some organisms can accumulate the silica and incorporate it to their bodies by biosilicification process. The organsims possessing this ability are widespread either when considering their position in eukaryotic tree of life, or their abundance in natural ecosystems. As a result, the whole global biogeochemical cycle of silica is controlled by biosilicificated organisms. In Chromista microorganisms, the silica is loaded to so-called "silica deposition vesicles" - membrane surrounded compartments, in which the silica is polymerated and formed into the final shape of silica structures during an ingeniously controlled in vivo process. Apparent differences in the process of silica deposition among Chromista microorganisms imply that this ability has developed independenty and repeatedly within the group. The most common silica structures are scales, bristles, cases, skeletons and cysts. The analogical structures often originated independently in unrelated lines of Chromista by means of convergent evolution. On the contrary, in some lineages of Chromista, the ability of biosilicification was suppressed. It is therefore very likely that the silica structures should...
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Evolution of silica structures in SAR protists
Čížková, Natálie ; Čertnerová, Dora (advisor) ; Kulichová, Jana (referee)
Silicon is an important element in the earth's crust. In nature it mainly occurs in the form of silicic acid. This element is used by marine and freshwater organisms to form their siliceous structures. The organisms that make up these structures are located throughout the phylogenetic tree and are not limited just to protist groups. The SAR line includes Stramenopila, Alveolata and Rhizaria. The main protist taxa forming the mentioned siliceous structures are in these groups. These are mainly diatoms, silicoflagellates, radiolarians and the group chrysophyceae. The formation of siliceous structures usually provides evolutionary benefits to organisms, such as protection of the cell from actions of biotic and abiotic factors. The availability of dissolved silicon changed during evolution, thus affecting the appearance and functionality of the structures of individual species. Structural changes were manifested by thinning of the shells, change of cell size, enlargement or decrease of pores, increase of the number of thorns or, conversely, their loss. The individual lines thus had to choose the best possible strategies in response to the decreasing availability of silicic acid. Therefore, there was frequent competition between the groups for the remaining dissolved silicon. The current diversity of...
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Evaporative water loss in geckos of the genus Paroedura
Myslíková, Tereza ; Starostová, Zuzana (advisor) ; Okrouhlik, Jan (referee)
Keeping a balanced state in terms of liquids in an organism, especially evaporative water loss regulation, is essential for all terrestial animals, including reptiles. Respiratory water loss and cutaneous water loss account for the highest percentage of total water loss. For this reason, the degree of evaporative water loss in reptiles can be primarily influenced by body dimensions, metabolism intensity and morphology of body surface scales. This thesis focuses on water loss through evaporation in Madagascan Paroedura geckos. The Paroedura are suitable for this research because they represent a monophyletic genus with a strongly supported hypothesis about phylogenetic relationships. The thesis adds some facts to this theory. At the same time, individual Paroedura species differ in body dimensions and habitat preference. The aim of the thesis was to find out whether individual representatives of Paroedura differ in TEWL, to specify the characteristics of the ancestral state of TEWL in this genus and to test which morphological and physiological factors influence TEWL. Further aim was to measure cutaneous water loss. Measuring was carried out by flow- through respirometry. The results show that individual representatives of Paroedura differ remarkably in TEWL figures. The reconstruction of the...
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Development of New Approaches in Descaling in the Continuous Production of Steel using High-Pressure Water Jet
Votavová, Helena ; Hloch,, Sergej (referee) ; Čecho, Ladislav (referee) ; Pohanka, Michal (advisor)
The thesis summarizes general and up-to-date knowledge of descaling during the continuous production of the hot-rolled steel and proposes further streamlining of this process in industrial production. The first chapter of the thesis deals with the origin, structure and physical properties of the scales. The second chapter describes the principles of descaling by using a high pressure flat water jet. The third chapter introduces the principles of the experimental methods and describes the used laboratory equipment. The fourth chapter summarizes the description of the particular experiments and their evaluation, and thus represents the focus of the dissertation. It is divided into six sections which independently solve predefined objectives of the dissertation. The first section focuses on the height and structure development of the scales on 54SiCr6 and HDT580X steels. It has been proven that the height of the formed scales increases with the time and temperature of the oxidation. The layered nature of the scales was verified at the same time. The second section examines the effect of the nozzle stabilizer on the focussing and distribution of the impact pressure of the nozzle. Experiments have shown that increase of 11 % of an average maximum nozzle pressure can be achieved, depending on the type of nozzle and the length of the stabilizer. The third section deals with the analysis of shadowgraphy images of water jet structures of the nozzles. A script was developed for analysis of these shadowgraphy photos by an adaptive thresholding. The findings are correlated using a regression analysis with an average heat transfer coefficient. It has been reported that most of the standard nozzle configurations produced disintegrated stream of little droplets at the height of the rolled surface. The fourth section focuses on the area of water jet overlap, especially the area of the so-called washout, where the impact pressure of one nozzle is reduced by the nozzle stream of the other. The influence of the pressure change and the mutual displacement of the nozzles is investigated. The analysis showed that the change of pressure did not have any effect on the percentage of reduction of the impact pressure in the area of the washout. It has been shown that if the area of the washout is wide the descaling efficiency in this area may be reduced. The fifth section builds on the previous section and focuses directly on the areas of waterjet overlaps. The influence of the change of rotation and pitch of the nozzles is studied. Experiments have shown that small changes in nozzle pitch do not have a significant impact on impact pressure and heat transfer coefficient. The effect of nozzle rotation, on the other hand, was a significant factor for the efficiency and homogeneity of the descaling of the surface. The last section deals with the effect of the rolling speed on the heat transfer coefficient in the descaling process. The regression model has shown that with a higher rolling speed there is a reduction in the average heat transfer coefficient. Conclusion summarizes the results of the dissertation and proposes which findings can be used in the industry to make the descaling process more effective.
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Influence of the oxide layer on the cooling of steel surfaces
Resl, Ondřej ; Pohanka, Michal (referee) ; Chabičovský, Martin (advisor)
This thesis deals with the influence of the oxide layer on the spray cooling of steel surfaces. As part of the work steel samples with oxide layer are made and the thickness, porosity and surface roughness of this layer are characterized. The average thermal conductivity of porous oxide layer is determined for different regimes of oxidation. Further, the influence of the oxide layer on the heat transfer coefficient during the spray cooling is experimentally investigated on created samples and the basic numerical simulation of the cooling is done for selected experiment with oxide layer. The thesis also contains theoretical introduction to given issue.
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The significance of silica structures in chromist microorganisms.
Nováková, Dora ; Škaloud, Pavel (advisor) ; Němcová, Yvonne (referee)
The silica is one of the most common elements in the Earth's crust. During erosion it is released in soluble form to the environment, where some organisms can accumulate the silica and incorporate it to their bodies by biosilicification process. The organsims possessing this ability are widespread either when considering their position in eukaryotic tree of life, or their abundance in natural ecosystems. As a result, the whole global biogeochemical cycle of silica is controlled by biosilicificated organisms. In Chromista microorganisms, the silica is loaded to so-called "silica deposition vesicles" - membrane surrounded compartments, in which the silica is polymerated and formed into the final shape of silica structures during an ingeniously controlled in vivo process. Apparent differences in the process of silica deposition among Chromista microorganisms imply that this ability has developed independenty and repeatedly within the group. The most common silica structures are scales, bristles, cases, skeletons and cysts. The analogical structures often originated independently in unrelated lines of Chromista by means of convergent evolution. On the contrary, in some lineages of Chromista, the ability of biosilicification was suppressed. It is therefore very likely that the silica structures should...
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Determination of thermophysical properties of scale layer on steel at high temperatures
Ondruch, Tomáš ; Votavová, Helena (referee) ; Pohanka, Michal (advisor)
The thesis deals with thermophysical properties of scale layer on steel and their determination at high temperatures. The first part summarizes fundamental characteristics of scales, it is also devoted to principles of heat transfer with emphasis on heat conduction. The following text presents current state of research on scales’ thermophysical properties. Subsequently, the thesis aims to experimental measurement of thermophysical properties by use of laser flash method and conducted measurement is described, as well. The following chapters present a finite-element numerical model of the measurement aparatus and computation technique for determination of scales’ thermophysical properties is explained. The obtained results are compared with available data and sensitivity analysis of selected model parameters is carried out.
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Forming lines molding hot weighing up to 100 kg
Smyček, Ondřej ; Humlíček, Jaroslav (referee) ; Omes, Jiří (advisor)
This project was made within the engineering studies and its aim was to design an assembly line to product assigned components of appropriate quality and quantity, using the technology of hot extrusion, both backward and forward. A series of technology steps was suggested, parameters necessary for individual operations were set and on this basis, adequate machines were chosen. The conclusion of this work contains technical-economical evaluation for the chosen options which expects the ten-year return with average production of 40 000 pieces.
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