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Supernova driven super star cluster wind
Jeřábková, Tereza ; Wünsch, Richard (advisor) ; Walch-Gassner, Stefanie (referee)
In this thesis we study the interaction of supernova ejecta in the environment of young massive clusters. It has been already shown that winds of massive stars can be thermalized by mutual interactions inside the cluster and drive the strong star cluster wind. The SNe are, as discrete and extremely energetic events, in all ways diferent from the continuous stellar winds. This triggers the question under which parameter and if at all can the SNe ejecta interaction from a smooth star cluster wind. Therefore we at first parametrize the SNe explossions and based on the 3D simulations in FLASH we show for the first time that the convergence of the SNe ejecta interaction to a smooth star cluster wind is controlled by a single parameter ΠSN . The paramater ΠSN estimates the mean number of interacting SN ejecta based on a comparison of supernova rate and crossing time of SN ejecta in a cluster. For high enough values ΠSN > 1 the cluster is able to build up smooth a star cluster wind. This allows us to use a 1D semi-analytic code WINDCALC to calculate the cooling of the hot gas due to dust and estimate under which conditions the SNe-inserted matter is captured. This may explain the origin of so-called anomalous globular clusters. 1
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Mixed-flow submersible water pump driven by hydrostatic motor
Para, Marcel ; Ranuša, Matúš (referee) ; Nevrlý, Josef (advisor)
Bachelor thesis solves the problem of a submersible, diagonal hydrostatic pump. This study describes the basic principles of hydraulics and equipment. The possibility of engaging the hydrostatic system as an amphibious vehicle is investigated in the Bachelor thesis. The work is written in cooperation with the sponsor of HYDRAULIC RESEARCH CENTRE, spol. S.r.o., which is part of SPL Holding., Inc.
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Hydrodynamic and thermal mode ling of reactive flow in the surroundings of intrusions
Jandová, Tereza ; Dolejš, David (advisor) ; Bruthans, Jiří (referee)
English Summary Intrusion of magma into the Earth's crust is associated with significant thermal perturbations, release of aqeuous fluids and formation of hydrothermal system. In order to better understand the feedback relationships between fluid flow, thermal evolution and permeability variations, we have modeled conductive and advective cooling of a shallow- crustal pluton using the SHEMAT software. Our model represents a two-dimensional cross section through the lithosphere with homogeneous material properties, whebery the heat and mass conservation equations are solved by finite difference method. We first calculate the stable lithospheric geotherm by emplying constant basal thermal flow of 40 mW m-2 and a constant surface temperature. Subsequently, we consider a rectangular magmatic intrusion emplaced at 5-10 km depth, which forms a contact aureole by conductive cooling. With time, a mushroom-like shape of the contact aureole is predicted. Inclusion of aqueous fluid flow into the model causes only a small alteration of thermal evolution mainly because the permeability is low and the fluid mass is negligible due to very low density under hydrothermal conditions. In addition to thermal effects, we have explored variations in hydraulic head in order to address the ensuing effects on the flow velocity. The...
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Actions on bridges caused by the water flow and floating items
Řezník, Jindřich ; Duchan, David (referee) ; Špano, Miroslav (advisor)
The subject of this thesis is the enumeration and analysis methods applicable to the calculation of loads on bridges from water and water-borne objects. It involves a hydrodynamics loads, loads from captured debris and from impacts of the individual water-borne objects and their clusters. It includes an assessment of the current situation, the teoretical analysis and model calculations on the concrete bridge with the evaluation of usable methods.
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Load moments acting on the sector weir box of hydraulic structure Roudnice nad Labem
Růžek, Patrik ; Haluza,, Miloslav (referee) ; Šulc, Jan (advisor)
This thesis deals with the determination of the load torque on the hydrostatic sector weir in Roudnice nad Labem. Problems are solved due to a fault in the lowering sector. The aim of this study is to determine the resulting load moments in positions and states of the upper and lower water taken from modeling research. I solved the issue as a 2D planar problem using AutoCAD where I subtracted the relevant data. All calculations I then counted in Microsoft Excel. Throughout the text is always concerned with the calculation of one meter structure. Performed by calculating, I found that in certain positions and conditions can cause problems when handling sector.
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Komplexní geochemický výzkum interakcí a migrací organických a anorganických látek v horninovém prostředí: Průběh hydrodynamických zkoušek na vrtech PTP3 a PTP4 na lokalitě Potůčky - Podlesí
Stavební geologie Geotechnika, a.s. ; Český ekologický ústav, Praha ; Klepáč, L. ; Záruba, J. ; Rukavičková, L
Popis terénních prací na obou vrtech - dokončení vodních tlakových zkoušek v průběhu vrtání na vrtu PTP-3, instalace multipakrového systému a následný monitoring tlaků v jednotlivých etážích na vrtu PTP-3, vodní tlakové zkoušky v průběhu vrtání na později zhavarovaném vrtu PTP-4, hydrodynamické zkoušky v průběhu vrtání, dlouhodobé hydrodynamické zkoušky, stopovací zkoušky.
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ELECTROCHEMICAL DETECTOR WITH ELECTRODES ARRAY AND ROTATING DISK
SAJDLOVÁ, Zuzana
The thesis deals with the testing and optimization of hydrodynamic conditions of the electrochemical detector, which consists of a flow cell containing the electrochemical sensor with an array of electrodes. The flow cell includes a rotating disc-shaped component, which allows radial flow of analytes along the sensor electrodes. This principle imitates the rotating disk electrode, with the difference that here the electrodes are immobile. Hydrodynamic phenomena in this case are similar to RDE. Therefore, the theoretical part of my work deals with hydrodynamics and mass transfer for the well-described case of rotating disk electrode. It was found that in the current set-up under certain conditions, an analyte flowed back from the output cell channel to the sensor, even at the laminar flow. This causes a nonlinear response of the electrodes and their low reproducibility. The solution is to reduce the distance between the rotation component and the electrodes surface and reduce flow speed of analyzed liquid towards the sensor. A novel type of sensor with annular electrodes was designed and tested. It showed four times higher conversion rate of the analyte compared with the originally used AC9 electrochemical sensor having electrodes in the form of full circles lying on a circumference of a common circle. Based on calculations, conversion of the analyte on the plane electrode can be increased up to 100% when using this annular sensor, adjusting flow cell and reducing of the input flow rate. The detector was connected to the liquid chromatograph and its function was tested on two substances - ascorbic acid and dopamine. For the current detector these parameters were set: dynamic range, linearity, noise, detection limit, time constant and the temperature range at which the detector can be operated.
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