National Repository of Grey Literature 26 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Heat treatment of aluminum castings
Mátl, Vojtěch ; Pernica, Vítězslav (referee) ; Kaňa, Václav (advisor)
This bachelor thesis deals with the topic of heat treatment of aluminium castings. The first part of this thesis comprises of casting alloys and casting technology summary, followed by description of aluminium heat treatment. The second part descibes an experimet, that examins the effect of conditions during aging upon final aluminium alloy properties.
Heat treatment of formed parts
Leška, Radim ; Jopek, Miroslav (referee) ; Lidmila, Zdeněk (advisor)
In the research part, the bachelor thesis deals with forming, the mechanism of plastic deformation and steels used for forming. It also describes the principles of heat treatment, specifically the methods used in the preparation of semi-finished products, pressings, and forgings, i.e., annealing, hardening, and tempering. In the practical part, several experiments were performed on C45 steel. The first of them verified the effect of strain hardening after compaction, the others were focused on recrystallization, full annealing, hardening, and tempering. The effect of deformation and heat treatment was assessed in terms of hardness, which was measured by the Vickers hardness test.
Machining of hardened parts
Havlík, Daniel ; Osička, Karel (referee) ; Polzer, Aleš (advisor)
This bachelor thesis is focused on the machining of hardened parts. The beginning of the work is devoted to the analysis of specific materials, 42CrMo4, 42CrMoS4 and 50CrMo4. Next described thing is heat treatment. The main part of this work consists of theoretical analysis turning of hardened parts and theoretical analysis of the thread whirling of ball screw, where the principle of ball screws is also described.
Surface Treatment Technology of Metallic Materials and its Applications using Electron Beam
Matlák, Jiří ; Dupák, Libor (referee) ; Houdková, Šárka (referee) ; Foret, Rudolf (advisor)
Fast deflection is one of the great advantages of an electron beam, making it possible to process a relatively large area at once and also to modify the distribution of the supplied energy. The dissertation deals with surface heat treatment with a focus on the effect of beam deflection on the process. Furthermore, the influence of processing speed and defocusing of the electron beam is studied. The principles of electron beam technology and the summary of surface heat treatment of various materials are presented in the literary part of the thesis. The experimental part is focused on the influence of process parameters on processing in the solid phase, carried out on steel 42CrMo4, and in in the liquid phase, carried out on alloy NiCrBSi. Especially changes in structure, hardness, shape of the processed area and wear resistance are evaluated on processed samples. The results are also evaluated from an energy perspective. Furthermore, an optimum combination of technological parameters is recommended for solid and liquid phase surface heat treatment.
Influence of hardening model on the results of cros-roll straightening simulation
Meňhert, Samuel ; Kubík, Petr (referee) ; Petruška, Jindřich (advisor)
This diploma thesis deals with simulation of cross-roll straightening using computational modeling with finite element method in software ANSYS. The main goal of this thesis is to quantify the influence of inaccurate knowledge of mechanical properties on the straightening process and correct setting of machine. It also aims for comparison of hardening models and their influence on the final curvature and residual stresses in the cross section of the bar.
An effect of cold showers on the psychological well-being
SCHWACHOVÁ, Nikola
Cold exposure activates the sympathetic nervous system and increases the concentration of beta-endorphin and noradrenaline in the blood, thus contributing to overall well-being. The aim of this thesis is to collect data of a selected sample of the population about their well-being and at the same time-frequency of hardening and find out the possible connection. 39 students from the Pedagogical Faculty of the University of South Bohemia participated in the study of hardening in the age range 19 - 25 years. The probands were divided into experimental and control groups. For about 3 months, 26 probands were hardened by cold showers. Data on the structure of the mental status of probands were obtained using the SUPOS questionnaire before and after the hardening period. Based on this analysis, it was found, that the experimental group showed a higher degree of well-being, with a simultaneous decline in impulsiveness, psychological unrest and anxiety expectations and fears, but statistically inconclusive. The positive influence of hardening of the organism on human well-being cannot be confirmed by the conclusion of this thesis.
History and current Situation of Winter swimming in Czechoslovakia and Bohemia
Řehulka, Filip ; Miler, Tomáš (advisor) ; Parkan, František (referee)
Title History and current Situation of Winter swimming in Czechoslovakia and Bohemia Goals To Gather availlable informations on the historical development of hardening as swimming in our country. Using the literature related to winter swimming, completed by medical literature. Method A historical method is used to capture the history of hardening in Czechoslovakia and Bohemia in chronological order. The main goal of this method is displaying whole in its main features for better and clearer understanding of this topic. Results Complete fragmented history of the winter swimming in our country and provide a more detailed view of the meaning of the hardening. Key words Hardening, History, Swimming, Winter swimming
A transcriptomic-based comparison of barley cultivars differing with respect to their low temperature acclimation capacity
Janská, Anna ; Ovesná, Jaroslava (advisor) ; Vaňková, Radomíra (referee) ; Honys, David (referee)
The PhD thesis is focused on a transcriptomics-based comparison of barley cultivars differing with respect to their low temperature acclimation capacity, with a particular focus on genes transcribed in the leaf and crown. The crown was of interest because of its importance for the winter survival of the plant. To involve both the first and the second phase of hardening, the test plants were exposed first to +3řC for 21 days, followed by - 3řC for one day. Freezing damage was assessed by measuring electrolyte leakage (Papers 2 and 3), using a modified version of a protocol developed by Prášil and Zámečník (1998). The same protocol was adapted to evaluate crown regrowth (Paper 2); for this purpose, the plants were cooled, then replanted and cut above the crown, and their survival rate calculated over the following week. Each RNA sample was queried by hybridization to an Affymetrix 22 K Barley1 GeneChip Genome Array (Close et al. 2004). The data were statistically analysed with the help of the software packages R, MAS 5.0 (Ihaka & Gentleman 1996) (Papers 2 and 3), Gene Spring GX 7.3 (Agilent Technologies, Santa Clara CA) and MapMan (Thimm et al. 2004; Usadel et al. 2005) (Paper 2), the "Self-Organizing Maps" algorithm (Kohonen et al. 1996) (Paper 3) and MIPS FunCat (Ruepp et al. 2004) (Paper 2). Paper...
Heat treatement of gear steels
Šnevajs, Matěj ; Řehořek, Lukáš (referee) ; Jan, Vít (advisor)
This bachelor thesis deals with suitable types of heat and heat-chemical treating of case hardening steel for production of gear wheels. The experimental part focuses on examination of two specific gear wheels made of 14 224 and ZF1A steel, which were donated by the company TATRA TRUCKS a.s. This bachelor thesis presents results of their hardenability, microstructure, hardness and microhardness of the case hardening layer.

National Repository of Grey Literature : 26 records found   1 - 10nextend  jump to record:
Interested in being notified about new results for this query?
Subscribe to the RSS feed.