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A comparison of the development of atmospheric deposition of nitrogen and phosphorus in different regions of the Czech Republic
SUCHÁ, Jitka
This thesis engages a comparison of the development of atmospheric deposition of nitrogen and phosphorus in different regions of the Czech Republic. The work explains the formation of atmospheric deposition and related terms such as the source of pollution, emissions, air pollution and nitrogen oxides. There are stated types of atmospheric deposition, sampling procedure and the process of determining the size of atmospheric deposition. This work describes the methods that were used in the calculations and evaluations. It also deals with the selection of suitable measuring stations for processing the development of atmospheric nitrogen deposition. The atmospheric deposition of phosphorus were not measured in the territory of the Czech Republic in the period from 2000 to 2010. The aim of this work is to find trends in time series of concentrations of NOx and statistical evaluation of the development of atmospheric nitrogen deposition. For these chapters were selected concentration of nitrogen oxides in the regional towns of the Czech Republic. In the chapter of spatial analyzes of the concentration of nitrogen oxides is selected Ústecký kraj, mainly due to the fact that this area is characterized by significantly high atmospheric deposition of nitrogen and total air pollution. A therm the Black Triangle is often used for this location.
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Influence of bimaterial interface on fatigue crack closure
Náhlík, Luboš
The article deals with the behaviour of a fatigue crack propagating across a bi-material interface. A stability criterion for the crack touching the bi-material interface, taking into account the residual stresses closing the crack faces is formulated. The linear elastic fracture mechanics is assumed to apply and the finite element method is used in the calculations. The criterion proposed is applied to determine the fatigue threshold stress for crack propagation across the interface. It is shown that the threshold values for crack propagation are influenced by the residual stresses closing the crack and by the specific combination of the elastic constants of the materials used. Two different geometries and two different loading ratios are considered. It is shown that the threshold values for crack propagation are influenced by the residual stresses closing the crack and by the specific combination of the elastic constants of the materials used.
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Plasma deposition of tungsten coatings
Brožek, Vlastimil ; Matějíček, Jiří ; Neufuss, Karel
Tungsten coatings on steel or ceramic substrates were prepared by water stabilized plasma generator WSP®. It operates on the Gerdien arc principle and produces plasma reaching temperatures up to 28000 K and velocities several Mach at the nozzle exit. Tungsten particles are melted and accelerated to velocities 30-70 m/s in the turbulent plasma that transports them to the substrate, where the particles rapidly solidify, forming characteristic splats and porous coatings. Protection of the molten 20-63 μm tungsten particles against oxidation by argon and acetylene shrouding was found to be inadequate. Therefore, a new method was tested, using hydrogen as a carrier gas in a special, house-built powder feeder. Another modification of the spraying process consisted of admixture of stoichiometric amount of tungsten monocarbide. During melting, it decomposes to W2C and carbon, which oxidizes and forms a protective cloud of carbon monoxide around the particles.
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Analysis of crack propagation in vicinity of bi-material interface in framework two parameter fracture mechanics
Seitl, Stanislav ; Knésl, Zdeněk
Existence of the interface between regions with different elastic properties have a pronounced influence on the behaviour of cracks The aim of the present contribution is an analysis of a crack growing in a vicinity of the interface between two different elastic materials.. The basic assumption of the contribution corresponds to two-parameter linear elastic fracture mechanics. The values of stress intensity factor KI and KII corresponding to normal and shear mode of loading and the value of T-stress are calculated for a generally oriented crack approaching to the interface. The calculations are performed by finite element method for short and long cracks. The dependence of KI, KII and T values on the distance and the orientation of a crack with respect to the interface is studied. It is shown that short cracks are influenced by the presence of the interface more significantly in comparison with long cracks. The results contribute to better understanding of short cracks behaviour in relation to microstructure of material.
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Plains volcanism in Tharsis region on Mars: Ages and Rheology of Eruption Products
Brož, Petr ; Závada, Prokop (advisor) ; Hauber, Ernst (referee)
Plains volcanism in Tharsis region on Mars: Ages and Rheology of Eruption Products Remote sensing data show clusters of low shield volcanoes in Tharsis volcanic province on Mars (Hauber et al., 2009). These low shield volcanoes and associated landforms are comparable with terrestrial plain-style volcanic products (Plescia, 1981) as defined by Greeley (1982) in the Snake River Plain in Idaho, which represents an intermediate style of volcanic activity ranging between flood basalts and the Hawaiian shields. While a number of recent studies addressed some aspects of low shield volcanoes, in particular their morphology, morphometry, and lava rheology, no systematic study including the chronology for the entire region of Tharsis is available so far. The goal of this work is to determine relative and absolute ages of low shield volcanoes and surrounding lava flows and their basic rheological properties. We used crater size-frequency distribution method (CSFD) developed by Hartman and Neukum (2001) and Ivanov (2001) for determination of absolute dating of the surface. For calculation of the rheological properties of the lava, we used methods established by Hiesinger et al. (2007). It is known that the low shield volcanoes on Mars consist of basaltic lavas that had low viscosities during their effusion, which can...
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Measurement of effective deployment format for lines in RAKO III
Blažíček, Martin ; Svobodová, Hana (advisor) ; Růžička, Václav (referee)
The bachelor thesis deals with the optimal production batches in the ceramic industry and to some extent the stock solution. In the theoretical part I try to summarize the issues concerning the optimal production batches, then the issue of stock, then the costs and theories of two models for calculating the optimal production batch. The next section deals with the characteristics of the firm. Explaining further production of ceramic tiles. The practical part then all the theoretical knowledge is applied to the particular case of the production of ceramic tiles. For the factory at Lubné Rakovník I was able to determine the optimal production batch sizes for each tile, the sensitivity of the cost of scaling benefits versus optimal production rate and ultimately the optimal length of production cycle.
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Homeland Studies Educational Walk in the Surroundings of Prague Focused on Geology
Budský, Pavel ; Stará, Jana (referee) ; Dvořáková, Michaela (advisor)
Deutsche Kurzfassung: Diese Diplomarbeit widmet sich der Kinderauffassung (den Präkonzepten) der gewissen naturwissenschaftlichen Phänomene - vor allem mit der Konzentration auf die geologischen Begriffe. In der theoretischen Einleitung werden die Arbeiten von 1. Piget und L.S. Vygotsky erwähnt, die in den Lehrbüchern des Lehrfaches "Mensch und seine Welt" der Elementarschule präsent sind. Die konkrete Forschung zielt dann auf einen ausgewählten Begriff: "das Gold". Zuerst wird mittels der Batterie der Teste das Niveau des Verständnisses dieses Begriffes bei den Schülern der vierten Klasse der Elementarschule in den Beschreibungskategorien der kognitiven Dimension, der affektiven Dimension und der Strukturalisierung festgestellt. Dann folgte eine thematische Exkursion ins Museum der GoldfOrderung in Jilove u Prahy, damit es möglich wird, im zweiten Test zu entdecken, wie sich die Beschreibungskategorien der Kinderauffassung des Begriffes des Goldes geändert haben. 86
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The peat quality and vegetation composition depending on land use
LEŠTINOVÁ, Iveta
Borkovická blata (moors) represent the largen bog in Třeboň Basin Area. Previously, there was mined pea tuntil 1979. The best preserved part of the moors was declared aprotected area in 1980. The mining impacted not only them so their immediate surroundings and landscape use. The work deals with the management of the surrounding areas, and how it may affect the quality of peatand its vegetation cover in nature reserve Borkovická blata. Fieldwork consisted of two parts: the first collection of peat and its chemical analysis (conducted in 20102011); second relevés with the development of land use surrounding areas (fieldwork was carried out from July to October 2014). On the moor were selected four phytocenological sites on the size of 5x5 m, on which were carried out sampling and survey. Selected sites showed at first glance significant differences by way of former use.
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The solution of abrasion Zr bands : contract number-771122
Svoboda, Jaroslav ; Štěpánek, I. ; Šmíd, Zdeněk ; Klášterka, Petr
The aim of works was experimentaly stated the value abrasion constant C in the Archard relation for Zr material who create coverning fuel thin stick in fuel assembly of the nuclear reactor. It was find that the abrasion mechanizmus depend on the amplitudesize and the frequency oscilation.By the small oscilations amplitude and high frequency is the abrasion smaller as by the low frequency and a big amplitude. The mechanizm of abrasion is another in both cases.
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