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The nutritional assesment of juvenile football players
KRÁL, Robert
The topic of the bachelor thesis is " The nutritional assesment of juvenile football players ". The emphasis on sports performance is placed on young sportsmen from an early age, which includes adequate nutrition. If this is not the case, the young athlete is at risk of problems manifested by poor performance, more frequent injuries and, last but not least, irreversible changes or developmental disorders. The theoretical part deals with energy overview, the representation and importance of macronutrients and micronutrients in the diet, drinking regime, problems of insufficient nutrition, assessment of nutritional status and finally dietary supplements. The data collection was done using a qualitative method. 12 informants were obtained using the snowball method, which was interviewed in a semi-structured interview. Each informant also provided a diet plan. Data analysis was performed using coding and categorization techniques on the data transcribed from the interview. Nutriservis Professional software was used to process the diet plan. The objectives of the study were to map the nutritional status and possible prevalence of malnutrition in the sports soccer players and to map the awareness of children and their parents about sports nutrition in the senior pre-school and junior football category. The research showed that the dietary habits of young footballers follow the recommendations of the child nutrition in terms of quality but not in terms of quantity. Children's awareness of the timing of meals with physical activity and energy use during exercise is significantly lacking. Awareness of nutrition is relatively adequate for their age and they can partially distinguish what is appropriate for them and what is not. Parents are well informed about healthy eating and lifestyle and try to take an interest in nutrition themselves, but do not have comprehensive adequate information about sports nutrition in childhood.
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Effect of microstructure on mechanisms of plastic deformation in fine-grained magnesium alloys
Minárik, Peter ; Král, Robert (advisor) ; Hadzima, Branislav (referee)
In this work were studied effects of the grain refinement on the mechanical properties and the corrosion resistance of magnesium alloys potential for medical applications - AE21 and AE42. Mechanical properties changed after ECAP pressing in consistency with literature data. Enhanced corrosion resistance in AE42 alloy was achieved by the grain refinement. Corrosion layer created on the surface was observed by light and electron microscopy. Effect of the grain size on the character of the corrosion layer was investigated. AE42 alloy is suitable for further investigation as potential biodegradable material. AE21 alloy was excluded from further investigation due to low corrosion resistance even after ECAP treatment.
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Effect of composition and microstructure on mechanical and corrosion properties in magnesium alloys with a potential for medical applications.
Minárik, Peter ; Král, Robert (advisor) ; Chráska, Pavel (referee) ; Landa, Michal (referee)
Title: Effect of composition and microstructure on mechanical and corrosion properties in magnesium alloys with a potential for medical applications. Author: RNDr. Peter MINÁRIK Department / Institute: Department of Physics of Materials, Faculty of Mathematics and Physics, Charles University in Prague Supervisor of the doctoral thesis: Doc. Dr. rer. nat. Robert Král, PhD., Department of Physics of Materials, Faculty of Mathematics and Physics, Charles University in Prague Abstract: Doctoral thesis is focused on the effect of thermomechanical processing through ECAP on the microstructure, mechanical properties and corrosion properties. The investigation was performed on the extruded magnesium alloys AE21, AE42 and LAE442, because their potential for medical applications. Microstructure development was characterized in detail by scanning electron microscopy together with detection of back scattered electros, transmission electron microscopy and positron annihilation spectroscopy. Development of mechanical properties was investigated by tensile and compression deformation tests and microhardness measurement. Corrosion resistance was investigated by linear polarization method. Fine-grain structure with grain boundaries with high angle misorientation was achieved by the thermomechanical processing. The resulting...
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Biodegradable Mg-based materials for stents and bone implants
Zemková, Mária ; Král, Robert (advisor) ; Stráská, Jitka (referee)
The bachelor thesis is focused on the effect of mechanical processing rotary swaging (RS), specifically on the microstructure, mechanical properties and corrosion properties. The investigation was performed on the magnesium alloy AE42 with a different number of RS passes, which can be useful for medical applications. RS is more efficient and cheaper alternative to different material processing methods producing fine-grained struc- ture. Fine-grain structure with grain boundaries with high angle misorientation was achieved by this process. Microstructure was inhomogeneous - the grain size decreased from the surface to the center. An improvement of mechanical properties with the increase in the number of swaging steps was observed. Processing also led to a decrease in corrosion resistance in this alloy. Microstructure development was investigated by electron microscopy scanning. Development of mechanical properties was characterized by compression deformation tests and microhardness measurements. Linear pola- rization method was used for the interpretation of corrosion resistance. 1
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Oxidation properties of complex concentrated alloys
Veverková, Eliška ; Minárik, Peter (advisor) ; Král, Robert (referee)
The thesis is focused on the oxidation characteristics of two complex con- centrated alloys - FeAlCrMo and FeAlCrV. Potentiodynamic polarisation tests were performed in order to characterize corrosion behavior of the alloys in two different corrosion media (aqueous solution of 3,5% NaCl and 0,5M H2SO4), in addition, high-temperature oxidation resistance was studied. All tests were perfor- med also for stainless steel used as a benchmark. An excellent corrosion resistance of both alloys was discovered, especially in the acidic solution, the studied alloys even surpassed reference stainless steel. On the contrary, poor resistance to high- temperature oxidation was observed. Particularly FeAlCrV exhibited catastrophic properties and resistance of FeAlCrMo is also inferior to stainless steel.
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