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Mutual interaction of multiple cracks growing in the particulate composite with brittle matrix under conditions of sub-critical crack growth
Slávik, Ondrej ; Ševeček, Oldřich (referee) ; Majer, Zdeněk (advisor)
In the first part of the submitted diploma thesis, the knowledge in the sphere of the fracture mechanics, related to the practice part of this thesis are summarized. In that the 2D parametrical numerical model of the particle composite with multiple cracks was created, using the finite elements method. Thanks to this model it is possible to find specific configurations which are showing the existance of multiple mutual interactions between these cracks, just by simple manipulation of the input data. In the calculations the influence of the residual stresses was considered which are formed during production of the material. The effect of the subcritical crack growth was taken into account as well in this thesis.
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Competition of cells within the population of yeast colony
Očková, Veronika ; Váchová, Libuše (advisor) ; Gášková, Dana (referee)
Competition is a very important natural phenomenon, which causes the rivalry of organisms, in cases such as space limitation or lack of nutrients. It occurs mainly in situations where organisms, including microorganisms live in large populations. Multicellular yeast colonies represent an example of such a population. After the population of yeast cells spends nutrients from the environment, the cells in colonies are able to respond to these changes by production of ammonia functioning as a signaling molecule. Subsequently, the cells are able to change their morphology and metabolism and, dependently on their location within the colony, to create a subpopulation of cells with specific characteristics and functions. It is likely that in the case of mixed colonies formed by the two different strains, a competition between the cells of these two strains could exist. Such rivalry can result in changes in the ratio of cells of the two strains within the colony population, so that the cells of one strain outweigh the other. In this diploma thesis, I compared the growth and development of giant colonies and competition between the cells of selected pairs of strains forming mixed colonies. I focused on the parental strain Saccharomyces cerevisiae BY and its variants labeled with fluorescent proteins. For...
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Competition of cells within the population of yeast colony
Očková, Veronika ; Váchová, Libuše (advisor) ; Gášková, Dana (referee)
Competition is a very important natural phenomenon, which causes the rivalry of organisms, in cases such as space limitation or lack of nutrients. It occurs mainly in situations where organisms, including microorganisms live in large populations. Multicellular yeast colonies represent an example of such a population. After the population of yeast cells spends nutrients from the environment, the cells in colonies are able to respond to these changes by production of ammonia functioning as a signaling molecule. Subsequently, the cells are able to change their morphology and metabolism and, dependently on their location within the colony, to create a subpopulation of cells with specific characteristics and functions. It is likely that in the case of mixed colonies formed by the two different strains, a competition between the cells of these two strains could exist. Such rivalry can result in changes in the ratio of cells of the two strains within the colony population, so that the cells of one strain outweigh the other. In this diploma thesis, I compared the growth and development of giant colonies and competition between the cells of selected pairs of strains forming mixed colonies. I focused on the parental strain Saccharomyces cerevisiae BY and its variants labeled with fluorescent proteins. For...
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Mutual interaction of multiple cracks growing in the particulate composite with brittle matrix under conditions of sub-critical crack growth
Slávik, Ondrej ; Ševeček, Oldřich (referee) ; Majer, Zdeněk (advisor)
In the first part of the submitted diploma thesis, the knowledge in the sphere of the fracture mechanics, related to the practice part of this thesis are summarized. In that the 2D parametrical numerical model of the particle composite with multiple cracks was created, using the finite elements method. Thanks to this model it is possible to find specific configurations which are showing the existance of multiple mutual interactions between these cracks, just by simple manipulation of the input data. In the calculations the influence of the residual stresses was considered which are formed during production of the material. The effect of the subcritical crack growth was taken into account as well in this thesis.
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