National Repository of Grey Literature 33 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Slupkové galaxie a modifikovaná Newtonova dynamika
Bílek, Michal ; Jungwiert, Bruno (advisor) ; Růžička, Adam (referee)
Our work has two recherchive parts. The first is devoted to the shell galaxies and we describe the observational facts here, different models of origin and the possibility of determining the gravitational potential with the use of shells. The second part is on the modified Newtonian dynamics (MOND). We explain what it consists in, its implications and its experimental tests. The third part is devoted to our numerical simulations of a shell system evolution both in the classical and modified dynamics. Our mission is to explain the differences in the two simulation theoretically and to verify, whether the result of the modified simulation oppose the observed shells around the galaxy NGC 3923. The conclusion is it doesn't, but our test is not very strong.
Galaxy interactions: dark matter vs. Modified Newtonian dynamics (MOND)
Bílek, Michal ; Jungwiert, Bruno (advisor) ; Kroupa, Pavel (referee) ; Stuchlík, Zdeněk (referee)
MOND is an observational rule for predicting the acceleration of stars and galaxies from the distribution of the visible matter. It possibly stems from a new law of physics. I list the theoretical aspects of MOND, its achievements and problems. MOND has been tested mainly in disc galaxies so far. Its tests in elliptical galaxies are rare because the MOND effects are small for them in the parts observable by the conventional methods. In the thesis, I explain the methods and ideas I developed for testing MOND in the ellipticals using stellar shells. Moreover, the shells enable us to test MOND for stars in radial orbits for the first time. The shells are results of galactic interactions. I discuss the shell formation mechanisms and summarize the findings from shell observations and simulations.
Influence of experimental chamber pumping on gas temperature
Balobanov, Damir ; Bílek, Michal (referee) ; Maxa, Jiří (advisor)
The master‘s thesis is focused on issue of pumping in the experimental pumped chambre of an environmental scanning microcope. In the theoretical part, there are presented microscopy as science. Afterwards the thesis is focused on electron microscopy and its problem and vakuum system, computer program used for preparation of simulation and study that the experimental part is based on. The experimental part contains the results of gas flow in the differential pumped chambre. The problematics were solved by Ansys Fluent system.
Comparative analysis of the gas flow through the aperture at low pressures using the continuum mechanics with the Monte Carlo method
Mardanova, Elvira ; Bílek, Michal (referee) ; Maxa, Jiří (advisor)
This thesis is based on the series of scholarly article dedicated to the issue ofpumping in the differential scanning chamber of an environmental scanning microscope. The thesis is based on Danilatos’s study where the pumping of the differential pumped chamber is solved by means of the Monte Carlo statistical method. The thesis performs analysis of gas flow at low pressures through orifice separating the spaces with a large pressure drop Dr. Danilate. The analyses will be used for the design of the experimental chamber which will serve for the experimental evaluation of the flow results in the chamber using the continuum mechanics.
Influence Boundary Layer In The Differentially Pumped Chamber
Bílek, Michal ; Hlavatá, Pavla
The goal of this thesis is the analysis of a gas flowing through the drain channels within the apertures of differentially pumped chamber of the Environmental Scanning Electron Microscope (ESEM). This thesis contains a verification of current simulation results of gas flow within the differentially pumped chamber published by D. Danilatos using Monte Carlo method in comparison with simulation results achieved by using simulation program ANSYS Fluent, which uses the mechanism of continuum for its calculations and where it was effect of the boundary layer taken into account.
Analysis of supersonic flow in experimental chamber by insertion of pressure and temperature probes
Šabacká, Pavla ; Bílek, Michal (referee) ; Maxa, Jiří (advisor)
For the supersonic flow mode, which occurs in the internal flow behind the aperture separating two spaces with a large pressure drop, the critical flow is a characteristic phenomenon. In the case of critical flow behind the aperture, a supersonic flow area with reduced pressure ending with a shock wave with a step change in state variables is created. When diagnosing velocities, which are obtained from the values of static and total pressure, due to the changes caused by the shock wave passage, correction of the diagnostic quantities obtained by measuring by means of mathematical relations taking into account the physical phenomena is necessary.
Pumping analysis in the experimental chamber for electron microscope using ANSYS system
Dostalová, Petra ; Bílek, Michal (referee) ; Maxa, Jiří (advisor)
The thesis is focused on issue of pumping in the differential pumped chambre of an environmental scanning microcope. In the theoretical part, there are presented microscopy as science. Afterwards the thesis is focused on environmental scanning electron microscopy and its problem and vakuum system, computer program used for preparation of simulation and study that the experimental part is based on. The experimental part contains the results of gas flow in the differential pumped chambre. The problematics were solved by Ansys Fluent system.
Supersonic Flow Measurement Within A Lowpressure Area
Bayer, Robert ; Hlavatá, Pavla ; Bílek, Michal
The goal of this paper is to describe the idea of measuring a supersonic gas flow within low-pressure areas in order to describe its behavior and to compare the measurement data with the generally described supersonic gas flow behavior derived from its behavior within high-pressure areas. This data should help to make low-pressure supersonic flow simulations more accurate.

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