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Purpose of epicentrum agency and marketpace for a new agency after its closure
Kohout, Jan ; Trunečková, Ludmila (advisor) ; Osvaldová, Barbora (referee)
This thesis recapitulates activities of Epicentrum agency which was reporting from the crisis places in the world and due to its termination of activities it attempts to define the meaning of Epicentrum. There is no doubt that Epicentrum was unique, but the important thing is to understand the causes and circumstances of its establishment and actions and to describe the way Epicentrum worked, including the both positive and negative aspects. Since the days of Epicentrum the world of media has changed fundametally (although it has not been that long). There is the phenomenon of media internetisation which the traditional media do not know how to deal with. Consequences of digitization have meant significant changes in journalists' work and the theme of this thesis is how could similar agency operate in these days. Today the proccess of producing the reports from the field is faster and cheaper which is advantage, on the other hand it is much easier to gather the large amount information for free these days and it is hard to convince media to buy it from such an agency. Therefore the integral part of this work is also a reflection on the value of on-the-spot reporting and its subsequent application possibilities on the market.
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Evolution of algorithm for artificial creatures
Kohout, Jan ; Mráz, František (referee) ; Holan, Tomáš (advisor)
The task of this work is to create an application which allows performing of experiments with evolution of artificial creatures. Behavior of each creature is managed by its algorithm. The algorithm is able to use creature's memory cells (which represent logical variables) and is the genome of the creature. By the crossing-over and mutation, the algorithm evolves. The second aim of this work is to make some tests with the application and describe their results.
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Fracture Behaviour of Steels and Their Welds for Power Industry
Al Khaddour, Samer ; Kohout, Jan (referee) ; Válka, Libor (referee) ; Dlouhý, Ivo (advisor)
Práce byla zaměřena na ověření platnosti koncepce master křivky pro hodnocení heterogenních svarových spojů, resp. teplotně stárnutých svarů. Současně bylo cílem disertace vyvinout kvantitativní model pro predikci referenční teploty lokalizující tranzitní oblast na teplotní ose za použití dat získaných z tahové zkoušky, a to za použití metody umělých neuronových sítí. Studie je současně zaměřena na heterogenní svarový spoj připravený tavným svařováním. Je zacílena na hodnocení lomového chování v tranzitní oblasti nejméně odolné části svaru, tj. tepelně ovlivněné zóny ferritické oceli v blízkosti zóny natavení s vysokolegovaným materiálem. Pro predikci referenční teploty master křivky je použita zmíněná metoda neuronových sítí, a to za použití dat z tahových zkoušek a měření tvrdosti. Predikovaná referenční teplota byla ověřována na základě výsledku experimentálních měření. Vytvoření modelu za použití neuronových sítí vyžaduje dostatečné množství dat a není vždy snadno tuto podmínku splnit. V případě sledovaného problému to znamenalo použití dat z dostatečně věrohodných zdrojů (skupiny Křehký lom ÚFM AVČR) a se známou metalurgickou historií. Smysl práce je tak možno spatřovat ve vývoji modelu neuronové sítě, která bude dostatečně přesně predikovat referenční teplotu. Celkově byla pro tyto účely použita data z 29 nízkolegovaných ocelí. Pro účely vývoje byly použity kromě hladkých zkušebních tyčí, rovněž tahové zkoušky s obvodovým vrubem testované při kritické teplotě křehkosti (mez makroplastických deformací) a při teplotě pokojové. Při tvorbě modelu byla postupně v různých kombinacích využita všechna data z uvedených zkoušek. Studie ukázala, že referenční teplota charakterizující tranzitní chování lomové houževnatosti oceli s převažující feritickou strukturou je jedinečným parametrem predikovatelným na základě vybraných charakteristik tahových zkoušek.
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Biocompatible titanium and cobalt alloys and their aplications
Volná, Kateřina ; Kohout, Jan (referee) ; Věchet, Stanislav (advisor)
This work is written in the form of literary research and deals with titanium and cobalt alloys and their application in dental medicine. Production of the individual metals, their mechanic, physical as well as chemical characteristics and various alloys which these elements can form are described in the first part. Furthermore, biocompatibility and basic division of biocompatible materials are explicated here. The work also deals with the basic requirements placed upon the materials used in dental medicine. Subsequently, five particular alloys are introduced: Ti-6Al-4V, Nitinol, Oralium, Oralium Ceramic and Ceramill Sintron and their characteristics and usage are described. In conclusion, the individual metals and their alloys are evaluated.
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Porovnání systému precizního zemědělství v podmínkách vybrané farmy v České republice
KOHOUT, Jan
The theme of the thesis is ,,Comparison of precision farming conditions in selected farms in the Czech Republic". The work deals with explaining and describing systems used for precision farming. The work will be divided systems by corporations that are offered and sold. And will also include systems, precision agriculture concerns from AGCO, CNH and John Deere. They will find answers to questions regarding the amount of investment in precision agriculture technology and efficiency systems.
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The Change Management in an Environment of Selected Sports Organizations
Žák, Vojtěch ; Kohout, Jan (referee) ; Blahutková, Marie (advisor)
Bachelor thesis deals with change management choice of club dance sport. The main intention is to propose applicable changes that can streamline the operation of the club and will affect the growth performance of dancers. The work is divided into three parts. The first presents the theoretical background, the next section is a sports organization and its trainers are analyzed by use to qualitative research focused on the training process and beliefs of the trainers. Based on the information we are given suggestions for changes which emerged from the qualitative research.
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Fatigue Behaviour of AZ31 and AZ61 Magnesium Alloys
Gejdoš, Pavel ; Lukáč, Pavel (referee) ; Kohout, Jan (referee) ; Podrábský, Tomáš (advisor)
This doctoral thesis deals with the fatigue behaviour of AZ31 and AZ61 magnesium alloy casted by advanced methods of casting squeeze casting. Based on the regression functions and measured fatigue data were determined fatigue characteristics of these alloys. The work also extends into the area of fatigue cracks in the AZ31 alloy. Were measured fatigue crack propagation rate on modified cylindrical specimens. The paper also outlines the possibilities for describing the fatigue behaviour of AZ61 alloy in extremely low-cycle fatigue.
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Influence of a Free Surface and Gradient Change of Material Properties on a Crack Behaviour
Ševčík, Martin ; Kohout, Jan (referee) ; Klusák, Jan (referee) ; Náhlík, Luboš (advisor)
This thesis was written under the supervision of Assoc. Prof. Luboš Náhlík, Ph.D. and Assoc. Prof. Pavel Hutař, Ph.D. The topic of this thesis is the study of a free surface effect and gradient change of material properties on a crack behavior. The common theme of the work is a fracture mechanics description of a crack behavior near a material nonhomogeneity. Here, the material nonhomogeneity can be understood either as a boundary of a body (interface between body and surrounding) or as a continuous change of material properties. The thesis is introduced by a review part where the state-of-the-art of the concerned topic is described. This part presents several stress state descriptions in the vicinity of some general singular stress concentrators, particularly a crack and a V-notch. The influence of the free surface on a fatigue crack front shape is discussed here. The review part follows with the fracture mechanics description of the graded materials. The problem formulation and the main aims of the thesis are stated in the following chapter. The core of this work is the fracture mechanical description of a crack propagating near the material nonhomogeneity. The thesis focuses on a stress field description near the free surface of the body where a change in a type of the singular stress field occurs. Methods used in generalized fracture mechanics are applied here to describe the stress field near the free surface. The difference between crack behavior in thin-walled and thick-walled structures is shown and supplied by relevant examples. Methods and procedures used are later utilized for estimation of a crack behavior in graded structures. The thesis is concluded by the discussion of obtained results in appropriate context.
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Influence of Plasma-nitriding on Fatigue Life of High-strength Steels under Biaxial Loading
Major, Štěpán ; Kohout, Jan (referee) ; Růžička,, Milan (referee) ; Obrtlík, Karel (referee) ; Pokluda, Jaroslav (advisor)
This work deals with fatigue life and fractographycal analysis of plasma-nitrided and virgin specimen made of the low-alloy high-strength steel. Specimens were subjected to in-phase combined bending-torsion loading. The work is focused on three groups of problems. The first group of problems was associated with the fatigue life and its prediction. The objective was to examine a relationship between the presence of the nitrided layer and fatigue life. The application of surface layers has significantly improved the fatigue life in the high-cycle region. An extended comparison between classical and advanced multiaxial criteria was performed. Criterions proposed by Marin and Matake were found to be most precise. The second objective of this work was to examine a relationship between the loading ratio ( is the bending amplitude and is the torsion amplitude ) and the fracture surface topography in the highcycle fatigue. Properties of fracture surfaces were quantified by many roughness and fractal parameters. Many roughness parameters start to incrise rapidly above a critical value of the loading ratio zc = 0,5. The last part of this work deals with the fractographical analysis of fish-eye cracks that were formed in plasma-nitrided steel specimens under symetrical bending, symetrical torsion and biaxial in-phase bending-torsion combinations.
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Structural and Mechanical Characteristics of Nickel-Alloyed Ductile Cast Iron
Tesařová, Hana ; Kohout, Jan (referee) ; Kruml, Tomáš (referee) ; Konečná,, Radka (referee) ; Pacal, Bohumil (advisor)
The aim of this dissertation work is the evaluation of the influence of nickel alloying on the structure and mechanical properties, both monotonic and dynamic, of nodular cast iron with ferritic and bainitic matrix. Two chock melts with 0.5 and 2.7 % Ni were used to study the nickel influence. The quantitative evaluation of structure of these melts using image analysis was done and basic tensile mechanical properties were determined. Subsequently, the time optimization of two-stage ferritic annealing and isothermal austempered heat treatment at 375 °C was performed with the aim to obtain optimal ferritic and bainitic structures with best static and dynamic mechanical properties. After ferritic annealing the nickel alloying contributes to substitution hardening of ferritic matrix which positively affects its strength and other mechanical properties. The higher nickel content in the bainitic structure causes the shift of phase transformation times to longer times which results in restricted production of small carbides and in bigger volume of retained austenite. These features were confirmed by observation in transmission electron microscope. Precise tensile and low cycle fatigue tests at temperatures 23 and – 45 °C were performed on the optimized structures of both nodular cast irons. As a result of the notch effect of graphite nodules, microplastic deformation of both nodular cast irons was observed at stresses which were lower than the yield stress. The Hollomon's equation very well describes the individual parts of tensile curves for both nodular cast irons including their mutual comparison. From the low cycle fatigue tests, the cyclic hardening/softening curves, the evolution of elastic modulus and hysteresis loop shape parameters, cyclic stress-strain curves and fatigue life curves were obtained for both temperatures and materials. Moreover, the decrease of retained austenite volume was measured by neutron diffraction and the evolution of surface relief was characterized during cyclic straining for both austempered nodular cast irons at both temperatures. On the basis of these results both cyclic plasticity and fatigue degradation mechanisms in relation to the cyclic strain localization were described for both nodular cast irons.
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