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The influence of Red Bull energy drink on speed, power and rebound performance of female volleyball players at the performance level
HARRISOVÁ, Helena Estella
The aim of the bachelor's thesis was to find out the influence of Red Bull energy drink on the speed, strength and rebound performance of female volleyball players at the performance level. Fifteen first-league volleyball players of VK Madeta České Budějovice club from the women's category were tested. The performance of female volleyball players was assessed using a bicycle ergometer, rebound board and hand dynamometer in the middle of the 2023/2024 season at the laboratory of load diagnostics at the department of physical education, University of South Bohemia. Each player underwent testing twice with a one-week break. Participants were given a Red Bull energy drink and a placebo in random order. Drinks were blinded. Anaerobic parameters were examined together with the blood lactate concentration using Wingate test, the average height recorded by the Bosc test and the maximum hand grip strength using the hand dynamometer. We did not confirm any significant effect of Red Bull energy drink on the observed performance. The t-test and Cohen's d were used to assess the statistical and substantive significance of the results. No significant effect of Red Bull energy drink on the observed parameters was found, with the exception of the maximum strength of the right-hand grip (d=0,29), the average height of the jump with a bounce from the left leg (d=0,22), maximum heart rate (d=0,29), maximum relative power (d=0,31), fatigue index (d=0,4) and lactate (d=0,2), for which substantive significant influence was recorded with only a small effect. Based on the evidence obtained from the measurements, it was proved that the Red Bull energy drink in a short period of time (20 min) had no effect on the performance of athletes.
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Optimization of Thermally Activated Building Structures
Oravec, Jakub ; Kalousek, Miloš (referee) ; Čekon, Miroslav (referee) ; Šikula, Ondřej (advisor)
The thesis deals with the modelling, analysis and optimization of thermally activated foundation piles using the in-house developed numerical software Epile. A sensitivity analysis of short energy piles was performed and a deep regression neural model was developed to predict the energy gain of the pile. A Bayesian optimization method was implemented to find the optimal parameters of the energy piles in order to maximize the financial and energy gain.
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Effect of substrate and geometry on the size of the anomalous Nernst phenomenon
Golub, Dmitrii ; Zázvorka,, Jakub (referee) ; Čech, Vladimír (advisor)
Anomální Nernstův jev se týká vzniku příčného napětí v magnetických materiálech při aplikovaném podélném teplotním gradientu. Tento jev slibuje aplikace v oblasti spinové kaloritroniky a zlepšené konverze tepelné energie. Zde jsme zkoumali vliv substrátu vzorku a experimentální geometrie na anomální Nernstův jev ve vzorcích tenkých filmů permaloye napařených na substrátech. Provedli jsme studii anomálního Nernstova jevu na vzorcích s čtyřmi různými substráty s podstatně odlišnou tepelnou vodivostí. Kromě toho jsme testovali čtyři různé techniky generování teplotního gradientu ve vzorcích: tři metody pro generování gradientu v rovině a jednu metodu pro generování gradientu mimo rovinu. Pozorujeme, že tepelná vodivost substrátu významně ovlivňuje velikost teplotního gradientu. V dvou konfiguracích v rovině jsme naměřili konzistentní koeficient anomálního Nernstova jevu, gradient teploty mimo rovinu byl odhadnut na základě získaných dat.
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Potential of AZ series magnesium alloys for ureteral stent manufacturing
Trnková, Zuzana ; Buchtík, Martin (referee) ; Doskočil, Leoš (advisor)
This master's thesis focuses on investigating the potential of magnesium alloys AZ31 and AZ91 for the production of ureteral stents. Potentiodynamic polarization (PDP) and electrical impedance spectroscopy (EIS) methods were used for electrochemical testing. Surface and microscopic analysis were conducted using scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). Immersion tests were used to characterize the corrosion solution and surface of AZ31 and AZ91 alloys. Fourier transform infrared spectroscopy (FTIR) with ATR module was used to determine the corrosion products on the surface of the alloys. The results showed that the AZ series alloys have potential for ureteral stent manufacturing, with AZ31 appearing to be more suitable than AZ91 as it provides more stable corrosion protection in the long term and the corrosion products do not form large particles that could lead to undesirable encrustation. Urea has also been shown to have a negligible impact on corrosion of AZ31 and AZ91 at lower concentrations, but at higher concentrations a significant impact on corrosion has been observed (especially in the case of AZ31).
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Biomimetic patterns in 3D printed auxetic metamaterials
Bečka, Filip ; Vozárik, Andrej (referee) ; Lepcio, Petr (advisor)
Diplomová práce se zabývá implementací biomimetických vzorů do 3D tištěných struktur s důrazem na studium auxetického chování a mechanických vlastností. Za tímto účelem bylo navrženo a technikou depozice taveniny připraveno šest typů struktur. Jako materiál byl zvolen polyethylentereftalát glykol (PET-G). Pro mechanické testování byla použita statická zkouška v tlaku doplněna o video záznam, který sloužil pro stanovení Poissonova poměru a pro sledování vlivu implementovaného vyztužení na deformační chování struktur. Navržené biomimetické vyztužení ještě více zvýšilo již tak dobrou účinnost auxetické struktury absorbovat energii. U nejvyššího stupně vyztužení byla navíc pozorována výrazně rovnoměrnější makroskopická deformace struktury. Vyztužení vedlo rovněž ke zvýšení napětí na mezi kluzu a specifického modulu pružnosti u auxetických struktur, zatímco u neauxetických struktur vedl přídavek vyztužení naopak ke snížení specifického modulu. Nakonec byl sledován vliv vyztužení na auxetické chování struktury. Zapojení vyztužujících prvků vedlo ke zvýšení Poissonova poměru, nikoliv však k překlopení do kladných hodnot. U struktur byl pozorován výrazný efekt hranic, kdy byly naměřeny různé hodnoty Poissonova poměru v různých částech připravených struktur.
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Petržalka - a sustainable city
Pružincová, Mária ; Pech, Zbyněk (referee) ; Kopáčik, Gabriel (advisor)
The entire world is trying to achieve carbon neutrality. Mitigation measures and carbon footprint compensations are the top topics of political summits in a developed society. However, if we want to think about future generations, we must talk about sustainability. How can we achieve carbon neutrality in a sustainable way, so that the steps we take have a long-term positive impact and are not just temporary patches on a leaky system? We have long known that it is not enough to install solar panels on roofs. It is not enough to build new neighbourhoods based on a modern low-emission principle. We must primarily focus on the development of what we have already built and into which we have already invested a considerable amount of energy and resources. Panel housing estates are a specific settlement structure that has become an integral part of the image of the cities in our region. Prefabrication resulted in typified elements and objects that are their characteristic manifestation, but each housing estate also has its unmistakable specifics. The development of Petržalka was unregulated for a long time. While new neighbourhoods with thousands of new residents were emerging on the periphery, the development of the inner city, with a few exceptions, stagnated. This area hides the greatest potential. Discussions about the fate of panel housing estates have shifted from radical humanisation through their sanitation to the preservation of their architectural values. Today we must move even further. In times of climate crisis and resource scarcity, it is essential to also think about sustainability and reducing global warming. The Sustainable Development Manual aims to create a set of measures that will lead the Petržalka locality Dvory IV to environmentally and socially sustainable development. The proposed measures are the result of analytical work based on qualitative research and a search of professional literature. The cornerstone of the manual is the identification of the problems of the area under consideration. I defined the problems based on observations and interviews with residents in situ. To gain a deeper perspective in solving the identified problems, I discussed with experts whose specialisation is related to the given topic.
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Materials for photovoltaic neurostimulators based on silicon photodiodes
Kunovský, Ondřej ; Weiter, Martin (referee) ; Glowacki, Eric Daniel (advisor)
Tato práce je zaměřena na možnosti neurostimulátorů s bezdrátovým přenosem energie, konkrétně se zabývá přenosem energie pomocí světla. Běžně používané neurostimulátory zahrnují bateriově napájené implantovatelné pulzní generátory a trpí problémem objemných baterií, které vyžadují invazivnější operace a nutnost periodické výměny. V této práci je zkoumána alternativa přenosu energie s využitím fotovoltaických diod. Monokrystalické křemíkové fotovoltaické diody jsou modifikovány a používány pro přeměnu energie ze světelné na elektrickou. Tyto diody byly rozřezány na různé velikosti aktivních ploch a byly zapojeny do sériových nebo paralelních zapojení. Tyto fotovoltaické články byly spojeny s elektrodami vyrobenými z osmi různých materiálů a se čtyřmi různými velikostmi fotovoltaických diod, aby pokryly širokou škálu možných neurostimulačních aplikací. Dále byl vyroben prototyp fotovoltaického stimulátoru skládající se z flexibilních elektrod a fotovoltaické diody. Tento prototyp byl úspěšně testován na modelech malých zvířat, kterými byli Hirudo verbena a Locusta migratoria. Tato práce charakterizuje řadu kombinací jednotlivých velikostí a materiálů elektrod s fotovoltaickými diodami pro různé intenzity a frekvence světla a vytváří mapu relevantních parametrů, z nichž lze navrhnout prototyp stimulátoru pro konkrétní aplikaci. Tato práce pokládá základ pro další vývoj fotovoltaických neurostimulátorů, které umožní nové experimenty a jednoho dne možná méně invazivní klinická zařízení.
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Preparation and characterization of layered double hydroxides on Mg substrates prepared by powder metalurgy
Kobzinková, Eliška ; Doskočil, Leoš (referee) ; Buchtík, Martin (advisor)
This thesis deals with the preparation and characterization of double-layered hydroxides (LDH) on Mg substrates prepared by powder metallurgy. The theoretical part deals with magnesium, magnesium powder metallurgy, and LDH coatings and methods of their preparation with a focus on MgAl-LDH. The theoretical part is concluded with a research study of current research in the field of preparation of LDH coatings on magnesium substrates and the influence of process parameters on the properties of coatings. The experimental part covers the process of optimization of MgAl-LDH on Mg samples prepared by powder metallurgy. In particular, the morphology and structure of the coatings and their elemental composition were evaluated. The evaluation was carried out using a scanning electron microscope (SEM) with an energy dispersive spectrometer (EDS). The optimized MgAl-LDH coatings were also evaluated for electrochemical corrosion properties by potentiodynamic tests in Hank's solution corrosion environment and phase analysis by X-ray diffraction (XRD).
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Zlín FCK Technology
Morávek, Jakub ; Kudla, David (referee) ; Štěpán, Marek (advisor)
The diploma thesis deals with the design of a residential building in the area of Malenovice near Zlín, where a new residential complex is to be built on the land of the current Malenovice sawmill, situated in close proximity to a four-lane road. The concept of this proposal is based on a detailed examination of human cycles and their impact on people in everyday life in relation to architecture. From the life cycle through the annual cycle and especially the daily cycle, professionally referred to as the circadian rhythm. The building, with its idea concept, orientation to the cardinal points, zoning of the apartment and also the shape solution, responds to the needs of man in terms of light comfort and at the same time addresses the greatest efficiency of the technologies used precisely in relation to light comfort, the form solution also creates conditions at the terrace level for the meeting of a wide range of inhabitants of the house - creating diversity. It reduces the need to illuminate the space during the day with artificial lighting, and after dark it addresses artificial lighting with respect to human health, thus also reducing energy consumption.
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Preparation and characterization of lignin modified by laccase enzyme
Hrušková, Lucie ; Obruča, Stanislav (referee) ; Kalina, Michal (advisor)
This master’s thesis focuses on the enzymatic modification of commercially available lignin using laccase enzyme and monitoring its impact on selected physical and chemical properties. Lignin is an attractive material for the production of renewable chemicals, materials, and energy, but its complex chemical structure poses a major obstacle to its effective utilization. Enzymatic modification appears to be a promising solution for its processing. Experiments were conducted under various conditions, such as pH, enzyme dosage, and reaction time. In the subsequent part of the experiment, the modified lignins were characterized and their results compared with those of the raw kraft lignin before modification. Molecular weight was determined using SEC-MALS, and the concentration of phenolic groups and antioxidant activity were measured. Structural changes were also monitored using FTIR. The results indicate that the enzymatic modification of lignin using laccase led to an increase in the molecular weight of the modified lignins, along with a decrease in the content of phenolic groups and a reduction in antioxidant activity. Based on the obtained results, it can be concluded that the action of the laccase enzyme resulted in lignin polymerization and the formation of new chemical bonds, leading to further aggregation.
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