|
|
VR Innovative Game Demo in UE4
Doležal, Josef ; Chlubna, Tomáš (referee) ; Milet, Tomáš (advisor)
The task of this bachelor thesis is to create a demo application for virtual reality using Unreal engine 4. Main mechanics are gravity sfere, simulating custom gravity and mirror portals with an ability to teleport a player to a previous or any other destination. All prefabs are free to be used in another Unreal engine 4 projects.
|
|
|
Tilt sensors
Hájek, Tomáš ; Caha, Luděk (referee) ; Beneš, Petr (advisor)
The topic of the Bachelor's thesis are MEMS sensors of inclination, which find their use inside integrated circuits, equipment of aerospace and automobile industry, but also in ordinary electrical appliance. The work serves the reader to build a grasp over production, usage, basic principles. Finally, it offers an overview of sensors to ease the orientation on the market. The design of the physical model, which can be used to prevent the sensor from apperance of mathematical errors, is tested in the practical part.
|
|
|
Numerická předpěťová modální analýza kmene
Skokan, Vojtěch
This work is investigating the effect of prestress on the results of the numerical modal analysis of tree stem and the effects of the degree of simplification of the geometry of the numerical model on the values of natural frequencies and modes of natural oscillation. The work aims to create credible numerical models of trunks and to use prestress to induce such a change in the diameter of the trunk that occurs in trees during the diumal cycle, thus simulating the transpiration stress in the trunk. During the work, three different methods of inducing prestress in the trunk are investigated and their impact on the values of the observed frequencies of strain models is assessed. In addition to artificial prestress, the work also assesses the impacts of the co-effect of gravity on the values of natural frequencies. This work is one of the first attempts to investigate the effect of mechanical stress caused by the transpiration flow using numerical simulation and can thus lay the foundation for future research in this field.
|
|
|
Visualization of root apoplastic pH in plants
Wernerová, Daša ; Fendrych, Matyáš (advisor) ; Paris, Nadine (referee)
Plant oriented movements, or tropisms allow the plant to actively respond to environmental stimuli to get more light, better access to nutrients and to grow roots deeper into the soil. Gravitropism drives the growth of roots along the gravity vector. Perception of gravity is triggered by the sedimentation of statoliths in columella root cap, but the exact signalling pathway behind this process is not known. Perception of gravity results in an unequal redistribution of the phytohormone auxin in the outer cell layers which leads to different rate of growth on the root's upper and lower side and bending of the root. The changes in auxin redistribution are accompanied by changes in apoplastic pH. Knowing an exact pattern of these pH changes could shed light on the mechanisms laying behind the gravitropic response pathway. While microelectrodes can be used to measure pH precisely, they are not suitable for the long-term imaging of growing roots. In the past few years, several pH sensitive dyes and genetically encoded sensors emerged. These can be used for long-term live in vivo imaging of pH changes in growing roots. In this thesis, I analysed the performance of several published pH sensitive genetically encoded sensors and available dyes in the roots of Arabidopsis thaliana. I observed that dyes varied...
|
|
|
Chaos v porušených polích černých děr
Witzany, Vojtěch ; Semerák, Oldřich (advisor) ; Heyrovský, David (referee)
The loss of complete geodesic integrability is one of the important consequences (and thus indicators) of deviation from the Kerr-type space-time. Indeed, it has been confirmed many times in the literature that even a highly symmetric perturbation of the Kerr or Schwarzschild metric can make the free test-particle motion chaotic. In this thesis, we study the test-particle dynamics in the field of a Schwarzschild black hole surrounded by a thin disc or ring, using, however, Newton's gravity with a simple "pseudo- Newtonian" potential to mimic the black hole. The Poincaré sections show that the (pseudo-)Newtonian system is slightly more chaotic than the general relativistic one. The difference seems to be correlated with the phase-space allowed region being more open towards the center in the pseudo-Newtonian case. Powered by TCPDF (www.tcpdf.org)
|
|
|
The mathematical theory of perturbations in cosmology
Novák, Jan ; Pravda, Vojtěch (advisor) ; Chopovsky, A. (referee) ; Scholtz, Martin (referee)
We deal with cosmological perturbation theory in my work. We investigate General Theory of Relativity in Higher Dimensions in the Chapter 1. I mention GHP-formalism and algebraical classification of spacetimes. I use spinors to show that spacetimes of dimension 4 are special. I discuss also Kundt spacetimes, which are interesting for perturbation theory of black holes. I work with perturbations of FLRW ST's in GHP formalism in Chapter 2, which we want to use in Cosmological Inflation. The final part of my thesis is connected with scalar perturbations in f(R)-cosmologies, that can be used for explaining accelerated expansion in the last 5 billion years. I investigate the Universe at the scales of 150 Mpc, where I could not use the hydrodynamical approach. Thus I work with the generalization of the Landau's mechanical approach. I need quasi-static approximation for getting the potentials Φ and Ψ, since the equations are too complicated for direct integration. I plan to use the result also for numerical simulation of motions of dwarf galaxies in these potentials. Powered by TCPDF (www.tcpdf.org)
|
|
|
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.
|
|
|
Thin discs and rings as sources of Weyl space-times
Kubíček, Jan ; Semerák, Oldřich (advisor) ; Žofka, Martin (referee)
Static and axially symmetric vacuum solutions of Einstein's equations can be descri- bed by the Weyl metric which only depends on two unknown functions, given by the Laplace equation and a line integral. In this thesis we study some properties of two Weyl space-times whose sources are one-dimensional rings - the Appell ring and the Bach-Weyl ring. On the behaviour of proper distances and geodesics in the central region we demonstrate that in Weyl coordinates these sources represent directional singularities. 1
|
|
|
Properties of the extreme charged black hole near horizon
Hejda, Filip ; Krtouš, Pavel (advisor) ; Svítek, Otakar (referee)
It is known, that there exists a limiting correspondence between certain part (including the horizon) of extremal case of Reissner-Nordström space-time and Robinson-Bertotti space-time and that different generalisations of this near-horizon limit are possible. The aim of the presented work is to examine some of the properties of such limiting transitions. Firstly it is stressed how the global structure is reflected in the limit and secondly which properties of the space-time do provide that physical distances are preserved in the limit. Besides the extremal case the subextremal and hyperextremal generalisations are studied. As a complementary topic, the global extremal limit is stated. That means a transition from a generalised (non-symmetrical) conformal diagram of the subextremal case to the conformal diagram of the extremal case of Reissner-Nordström solution.
|
|
|
Selected gravitational effects in the Universe
Franc, Tomáš
Title: Selected gravitational effects in the Universe Author: Mgr. Tomáš Franc Department: Astronomical Institute of Charles University Supervisor: doc. RNDr. Marek Wolf, CSc., Astronomical Institute of Charles University Abstract: In this Thesis we have given an overview of tidal phenomena with their explanations and also explained the gravitational assist with examples of its use. We have created many pictures and 17 animations for better understanding of these topics. This part of the Thesis is focused on high school students and their teachers, it can be used by teachers for their inspiration for lessons, or students and more generally people interested in these topics can read this part as a study text. The main part of the Thesis is the result of research conducted on 13 high schools in the Czech Republic. 800 students took part in the research; its purpose was to find out students' knowledge of tidal phenomena and the gravitational assist. The research was carried out in the form of questionnaires. Keywords: gravity, tidal phenomena, gravitational assist, pedagogical research
|
guest ::
