|
|
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.
|
|
|
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.
|
|
|
Modification of the crystallographic texture of austenitic steel by 3D printing
Fábry, Adam ; Dočekalová, Kateřina (referee) ; Koutný, Daniel (advisor)
The microstructure, and therefore the mechanical properties of the material, depend on the cooling rate and the direction of the temperature gradient during cooling, which can be easily influenced in additively manufactured metal parts. In previous research, this change has been achieved by altering the scanning strategy during production. This work focuses on modifying the crystallographic structure of material X30Mn22 by varying the laser speed and power while maintaining a constant meander scanning strategy without rotation. To determine the applicable production parameters, a test of simple welds was conducted, providing a basis for future production and testing of bulk samples. The suitability of the production parameters and the microstructure achieved in the sample cross-section were evaluated using porosity on the fabricated bulk samples, and the microstructure was depicted using EBSD maps, showing significant changes in microstructure solely by altering the laser production parameters. Tensile samples were further fabricated for selected microstructure samples, and their mechanical properties were tested. The results of tensile tests showed differences between individual microstructures of 18% for yield strength and up to 10% for ultimate tensile strength. However, the most significant difference was in the achieved tensile modulus, which differed by up to 27%. The work provides fundamental insights into modifying and adjusting the structure of manganese-rich material by changing laser power and speed settings.
|
|
|
Biofunctionalization of water soluble CdTe quantum dots
Šibíková, Anna ; Drbohlavová, Jana (referee) ; Pekárková, Jana (advisor)
This bachelor thesis is focused on the research on biofuncionalization of water-soluble glutathione modified CdTe quantum dots (QDs). The thesis is divided into three parts. The first part is a theoretical introduction to the QDs and their synthesis, modifications and applications in biology together with an introduction to proteins and bioconjugation of QDs and BSA. In the second part I present the experimental results of water-soluble glutathione modified CdTe-GSH QDs preparation. The QDs were cleaned and bioconjugated with BSA at different concentrations. This is described in the third part of the thesis. I also discuss the obtained experimental results in the frames of available literature.
|
|
| |
|
|
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.
|
|
| |
|
| |
|
|
The assessment of the capacity of bridge profiles on the Bobrava river
Bezděk, Josef ; Roubcová, Radka (referee) ; Milerski, Rudolf (advisor)
This diploma thesis “The Assessment of the Capacity of Bridge Profiles on the Bobrava River” focuses on making calculations of a system of bridges by using HEC-RAS PC software. This thesis assesses the capacity of bridges and applies knowledge of model research to design increase the capacity. A model of a stream on Bobrava River will be created. Furthermore, modifications of a river bed and bridge profiles will be realized for safe conversion Q100 by these constructions. Subsequently, a model of the modified stream n Bobrava River will be made. Lengthways profiles of water surface, table and graphic outputs from HEC-RAS PC software and modified designs will be output.
|
|
|
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).
|
guest ::
