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Solving flows with very low Mach numbers
Kučera, Václav
Nazev prace: Reseni stlacitelneho proudeni s malymi Machovymi cisly. Autor: Vaclav Kucera Katedra (listav): Katedra numericke matematiky Vedouci diplomove prace: Prof. RNDr. Miloslav Feistauer, DrSc. Abstrakt: Tato prace se zabyva numerickym resenim nestacionarniho nevazkeho stlacitelneho proudeni pomoci nespojite Galerkinovy metody. Experimentalni rad presnosti metody je ovefen v pfipade skalarni rovnice konvekce-difuze. Pro Eulerovy rovmce vyzaduje explicitni casova diskretizace vyrazne omezeni casoveho kroku, umerne Machovu cislu. K odstraneni teto nevyhody je na Eulerovy rovnice aplikovana semiimplicitni linearizace z prace citovane jako [4]. Numericke experimenty ukazuji, ze tento algoritmus nedava dostatecne dobre vysledky v pfipade malych Machovych cisel. Ukazeme., ze to je zpusobeno volbou okrajove podminky. Navrzeny jsou dve techniky vedouci ke zlepseni: jednoducha heuristicka modifikace standardnich okrajovych podminek a odvozeni novych okrajovych podminek zalozenych na metode charakteristik. Ty druhe jsou testovany pro Machova cisla 0.7 az 10"6. Na zaver je navrzena semiimplicitni linearizaci vazkych clenii jako rozsifeni schematu pfevzateho z citovane prace, pro nedostatek casu neni implementovana. Puvodnim pfinosem autora je hlavne aplikovani jiz existujici prace na pfipad malych Machovych...
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The study of the influence of process parameters on the roughness of the cut for flame laser cutting of stainless steel
Kučera, Václav ; Hála, Michal (referee) ; Mrňa, Libor (advisor)
Thesis presents a study of the influence of process parameters on the roughness of the cut surface. The test material is 1.4301, namely austenitic stainless steel. When a parameter is the surface roughness not change too much. In some samples there were defects in the form of cutting burrs. The graphs below show the estimated minimum change one parameter (the lowest point of the curve). As the most important parameter from a technological point of view, cutting speed, constitutes a major cost item compared to the auxiliary gas and power. For samples with a thickness of 2 mm and 3 mm has been achieved good results with decrease in the cutting rate of 30% percent, although when cutting the samples with a default rate was almost identical results. For samples with a thickness of 3 mm the best results were achieved by increasing the speed by 30 %, decrease the rate should be compared with the economy of the process to reduce surface roughness. For changes in the gas pressure was achieved the best values at a pressure increase of 30 %. When you change the performance of the best results are achieved by setting 100–90 % capacity.
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Thermoacoustic measurement of ultrasonic power
Kučera, Václav ; Čížek, Martin (referee) ; Rozman, Jiří (advisor)
The thesis deals with ultrasound intensity and power measuring methods of the medical diagnostic systems, especially with thermoacoustic method. Then the concept of thermoacoustic sensor is processed and it is checked by comparison with the power of ultrasound system measured by the hydrophone in ultrasonic measuring tank. In the leading chapter basic parameters of general ultrasonic field are described. Next part deals with particular ultrasound intensity and power measuring methods. The last part deals with projecting of the thermoacoustic sensor, measuring with this sensor, measuring with hydrophone and comparison of this measurements.
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Pulsed high power supply operating at low frequencies range for plasma generation
KUČERA, Václav
The present work focuses on high power pulse sources for plasma excitation. The main objective of the work is the development and construction of a pulse power source for generation of plasma discharges with high degree of ionization. The construction of the pulse power supply is based on semiconductor elements, especially on IGBT transistors. The pulsed power supply enables to work with peak currents and peak voltages up to 200 A / - 1000 V at frequencies of 100 Hz range. The bachelor thesis includes parts with the theoretical introduction and circuits design together with the description of the power supply assembly. The functionality of the pulsed power supply was verified during the real experiment in laboratory and measured data are attached.
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Piano as an intermediate of contemporary composer
Dušek, Jan ; Bartoň, Hanuš (advisor) ; Kučera, Václav (advisor) ; Filas, Juraj (referee) ; Matějů, Zbyněk (referee)
This master´s thesis is deal with a piano and its technical possibilities. The main focus is heeding especially on techniques used in music of 20th century, its possibilities of performance and writing. In this thesis are besides orthodox techniques (playing on the keys) also non-orthodox techniques (prepared piano, playing inside of the instrument). In attachments are photos of playing certain non-orthodox techniques, on the CD its sound result.
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The Aesthetics of Modern Diatonic Music Language
Janošík, Michal ; Kučera, Václav (advisor) ; Hořínka, Slavomír (referee) ; Zouhar, Vít (referee)
This thesis tries to solve some questions connected with the aesthetics and structure of diatonic music language in the context of modern artificial compositions. Each of the four chapters is focused on different aspects of diatonic composition and its use especially in the field of so-called minimalist music. The chapter called Music Means and its Effect summarises the aesthetic views on the development and further direction of modern music language. It deals with the kinaesthetic aspect of music and its direct influence on the audience via sound frequence, dynamics, colour, time, repetitiveness or monotony, dissonance and consonance etc. There is the summarisation of practical professional experience from the point of view of different genres and styles. This chapter also studies the possibilities to use particular music means within modern music. The chapter Diatonics analyses and theoretically explains the structure of pentatonic, diatonic, chromatic and pandiatonic tone system and thinks about the use of diatonics in the field of minimalist music. The chapter Diatonics in Own Compositions solves the particular compositional problems connected with the use of diatonics in own compositions. Finally, the chapter called Interpretation of Minimalist Music is about practical experience with interpretation of minimalist compositions and its specific features.
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The Integration Of Electroacoustic Component In Instrumental Music
Trojan, Jan ; Slavický, Milan (advisor) ; Kučera, Václav (referee) ; Kurz, Ivan (referee)
The intention of this Diploma Work is to create a complex text about the possibilities of using an electroacoustic component in Instrumental music. The work predominantly deals with its participation not only as an instrumental inset in my composition output, but also as an element affecting my composition language.
The aim of this text is to find out to what degree it is to possible to influence a language of a contemporary composer and his or her instrumental sentiment by the electroacoustic component.
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The influence of microinterval music on my music language
Stojilkovič, Marjan ; Kurz, Ivan (advisor) ; Kučera, Václav (advisor) ; Kopelent, Marek (referee) ; Bláha, Ivo (referee)
Ljuba Marič (1909-2003) first studied composition with Josip Slavenski at the Belgrade Music School (1925-1929), and continued her studies with Josef Suk at the Master School of Prague Conservatory (1929-1932) where she took Alois Hába´s course in quarter-tone music at the same instution from 1936 to 1937. The works she composed during the 1930´s were characterised by a radical will to break ties with traditional, mainly romantic music, so che chose to be influenced by the free atonal, predodecaphonic works of Arnold Schoenberg.
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Komparace vybraných aspektů spotřebních daní v České republice a v Rakousku
Kučera, Václav ; Svátková, Slavomíra (advisor)
Cílem této bakalářské práce je analyzovat hlavní rozdíly v aplikaci spotřebních daní v Rakousku a v České republice. Po prvních dvou kapitolách, které teoreticky představují oba systémy spotřebních daní, srovnává třetí kapitola vybrané části obou zákonů a zaměřuje se na významné odlišnosti, případně body společné oběma systémům. Práce poukazuje na překvapivě velké množství odlišností, přestože některé jsou takřka zanedbatelné. Informace k této práci poskytly příslušné zákony, novely těchto zákonů, věstníky jednotlivých ministerstev a podkladový materiál pro kurz předmětu Zdanění spotřeby I., probíhající v letním semestru školního roku 2006/07. Nutno podotknout, že spotřební daně v porovnání s ostatními daněmi nemají od roku 1993 téměř žádnou vlastní publikaci. Veškeré údaje se vztahují ke stavu platném k 1. 1. 2008.
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