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Gear coupling modification
Mahel, Pavel ; Prokop, Aleš (referee) ; Řehák, Kamil (advisor)
This thesis deals with the design of a gear coupling. The main intention is to design the optimal shape of the clutch gearing for the given operating conditions. Due to the special barrel shape of the teeth on the external gearing, these couplings enable the torque to be efficiently transmitted even in the case of misalignment of the connected shafts. In the case of an improperly designed coupling, a number of problems can occur that could affect the life of the coupling. These problems include in particular the generation of excessive vibrations and noise. It is necessary to choose the right lubrication system for long-term coupling life. To eliminate problems with gear couplings, it is necessary to ensure a suitable distribution of contact pressure at a given degree of misalignment. The introductory part of the thesis contains a comprehensive view of the issue of gear couplings. The next part deals with the structural design of the whole gear coupling and the improvement of the existing model. The following is a description and analysis of two different computational models of gearing that allow for different maximum degree of misalignment. The difference between the two gearing models is in the different geometry of the tooth shape on the hub. In the computational analysis, the most important monitored parameter was the course of contact pressure on individual teeth at a given degree of misalignment. From the performed computational analyses, result files are processed that compare the contact pressure and the number of teeth in engagement for different degrees of misalignment. The above analyses were performed using the finite element method in the calculation program Ansys Workbench.
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Improvement of Wood Properties in Aviation
Novosád, Matěj ; Katrňák, Tomáš (referee) ; Löffelmann, František (advisor)
The work focuses on improving the useful properties of wood in aviation using known methods of its modification. The structural and mechanical properties of wood are described together with a basic overview of some aircraft structures using wood. A substantial part of the work consists of a description of individual modification methods, including their impact on the mechanical properties of wood. The work ends with a summary of some suppliers of wood as a material for aircraft construction and also with a description of some new methods of modification.
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Wood stabilizers for its use in cement composites
Vaněk, Dominik ; Vacula, Miroslav (referee) ; Bydžovský, Jiří (advisor)
The thesis focuses on the analysis of the effects of wood stabilizers in wood cement composites. Moisture, dimensional, thermal and mechanical parameters of wood cementitious materials were monitored. In addition, the effect of replacing cement with alternative components was also assessed. Within the theoretical part, a survey of the literature findings is made with a focus on the stabilization of wood in these composites. The theoretical knowledge was evaluated and subsequently the types and concentrations of stabilizers or modifiers were proposed for the experimental part of the work. In the experimental part, the effect of stabilizers on selected wood parameters was first analyzed. Next, the hydration parameters of the individually stabilized wood-cement mixtures were assessed. These parameters were evaluated and then the formulations of the wood cement mixtures from which the cement-bonded particleboards were made were proposed. Selected mechanical properties were determined on these boards, which were evaluated and assessed including microstructural analysis.
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Functionalization of Polypropylene by Grafting
Kelíšek, Petr ; Sadílek, Jiří (referee) ; Petrůj, Jaroslav (advisor)
This bachelor thesis deals with the study of functionalization of polypropylene by grafting. The theoretical part summarizes current knowledge about the properties of polypropylene, polylactic acid, radical grafting, factors influencing the properties of such functionalized polymer and modification of immiscible polymers by the aid of compatibilizer. In the experimental part, samples of polypropylene grafted with polylactic acid, and blends of polypropylene with polylactic acid were prepared on an internal mixer under different conditions. Temperature and torque were monitored during the mixing. Created materials were evaluated by comparing their base properties (tensile strength, melt flox index).
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Game Server Administration Client
Cigán, Tomáš ; Michal, Bohumil (referee) ; Kašpárek, Tomáš (advisor)
This bachelor thesis focuses on the description of game servers of the most common computer games. The details and differences between particular game servers as well as administration control are included. Also structure of plugins and plugin installation procedures for such servers is described in details. The main target of the thesis according to the previous research is to analyze and develop uniform system for controlling the game server and its plugins throw web application. At the end of the thesis there is detailed description of creating a new game server implementation support.
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Chemical modifications of hydrogels from natural polysaccharide
Poštulková, Hana ; Žídek, Jan (referee) ; Vojtová, Lucy (advisor)
V teoretické části práce by shrnuty chemické a fyzikální vlastnosti, chemická struktura a využití přírodního polysacharidu gum karaya. Hlavním cíle diplomové práce byla alkalická modifikace původní nerozpustné gum karayi na rozpustný produkt, který může být v budoucnu využit pro další aplikace například v medicíně. Nerozpustnost gum karayi je způsobena přítomností acetylových skupin a vícemocných iontů ve struktuře polysacharidu. Byly zkoumány optimální podmínky pro modifikační proces. Pro modifikaci byl použit hydroxid sodný, draselný nebo amonný a čas modifikace od 1 minuty po 24 hodin pro roztok originální gum karayi s koncentrací od 0,1 do 3 %. Pro určení chemického složení originálního a modifikovaných vzorků byla využita FTIR. Bylo prokázáno, že vzorky A2, B1 - 7, C1 - 8 a E1 - 2 byly zcela deacetylovány, protože pás pro acetylovou skupinu nebyl v FTIR spektrech pozorován. Odstranění acetylových skupin alkalickou modifikací bylo taktéž potvrzeno 13C CP MAS NMR. Pomocí XRD byl prokázán amorfní charakter originálního vzorku. Množství vlhkosti a teplotní stabilita vzorků byly zkoumána pomocí TGA. Bylo zjištěno, že termální stability originální gum karayi je vyšší než u modifikovaných vzorků. Termální stabilita modifikovaných vzorků byla ovlivněna reakčními parametry. Entalpické změny vzorků byly studovány pomocí DSC, nicméně nebyly pozorovány žádné významné rozdíly mezi modifikovanými vzorky a originální gum karayou. Prvkové složení bylo určeno pomocí ICP-OES a byla potvrzena přítomnost vápníku, draslíku a hořčíku ve struktuře polysacharidu. Molekulová hmotnost modifikovaných vzorků byla měřena pomocí GPC a byla stanovena na 8 milionů g·mol-1. Reologické měření roztoků gum karayi bylo provedeno pro určení lineární viskoelastické oblasti. Dále byl sledován efekt NaCl na viskozitu originálního vzorku. Viskozita klesala s vyšším množstvím NaCl. Pokles viskozity originálního vzorku je způsoben výměnou vápenatých iontů za sodné, což vede k uvolnění fyzikálně vázané struktury a tím k vyšší rozpustnosti vzorku ve vodě.
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