Regular and Chaotic Motion in General Relativity: The Case of a Massive Magnetic Dipole

Circular motion of particles, dust grains and fluids in the vicinity of compact objects has been investigated as a model for accretion of gaseous and dusty environment. Here we further discuss, within the framework of general relativity, figures of equilibrium of matter under the influence of combined gravitational and large-scale magnetic fields, assuming that the accreted material acquires a small electric charge due to interplay of plasma processes and photoionization. In particular, we employ an exact solution describing the massive magnetic dipole and we identify the regions of stable motion. We also investigate situations when the particle dynamics exhibits the onset of chaos. In order to characterize the measure of chaoticness we employ techniques of Poincar\'e surfaces of section and of recurrence plots.Comment: 11 pages, 6 figures, published in the proceedings of the conference "Relativity and Gravitation: 100 Years after Einstein in Prague" (25. - 29. 6. 2012, Prague

Transition from Regular to Chaotic Circulation in Magnetized Coronae near Compact Objects

Accretion onto black holes and compact stars brings material in a zone of strong gravitational and electromagnetic fields. We study dynamical properties of motion of electrically charged particles forming a highly diluted medium (a corona) in the regime of strong gravity and large-scale (ordered) magnetic field. We start our work from a system that allows regular motion, then we focus on the onset of chaos. To this end, we investigate the case of a rotating black hole immersed in a weak, asymptotically uniform magnetic field. We also consider a magnetic star, approximated by the Schwarzschild metric and a test magnetic field of a rotating dipole. These are two model examples of systems permitting energetically bound, off-equatorial motion of matter confined to the halo lobes that encircle the central body. Our approach allows us to address the question of whether the spin parameter of the black hole plays any major role in determining the degree of the chaoticness. To characterize the motion, we construct the Recurrence Plots (RP) and we compare them with Poincar\'e surfaces of section. We describe the Recurrence Plots in terms of the Recurrence Quantification Analysis (RQA), which allows us to identify the transition between different dynamical regimes. We demonstrate that this new technique is able to detect the chaos onset very efficiently, and to provide its quantitative measure. The chaos typically occurs when the conserved energy is raised to a sufficiently high level that allows the particles to traverse the equatorial plane. We find that the role of the black-hole spin in setting the chaos is more complicated than initially thought.Comment: 21 pages, 20 figures, accepted to Ap

Co má cenu... Jindřicha Chalupeckého

Komentář výsledků Ceny Jindřicha Chalupeckého 2012Komentář výsledků Ceny Jindřicha Chalupeckého 2012Comment of results of Jindřich Chalupecký Award 201

atHELLiér

Výstava prací studentů ateliéru Malba a ilustrace SUPŠ Jihlava-Helenín v galerii Černá linka na KVV PdF MU v BrněVýstava prací studentů ateliéru Malba a ilustrace SUPŠ Jihlava-Helenín v galerii Černá linka na KVV PdF MU v BrněThe exhibition of student's works of atelier Painting and illustration SUPŠ Jihlava-Helenín in the Black line gallery, Faculty of Education, Brn

Hotel Garni

Projektová dokumentace garni wellness hotelu o jednom podzemním a třech nadzemních podlažích z monolitického železobetonového skeletu, vyplněno zdivem POROTHERM, vodorovné konstrukce prefabrikované panely HELUZ, zastřešeno jednoplášťovou plochou střechou a šikmou střechou s dřevěným krovem a plechovou krytinou.Project documentation of garni hotel with wellness service of one basement and three floors from reinforced concrete monolithic skeleton, filled with masonry POROTHERM, horizontal structures prefabricated panels HELUZ, roofed by single-layers flat roof and sloping roof with wooden eaves and metal roofing.

Masonry house

Cílem zadaného tématu bakalářské práce ,,zděný rodinný dům“ je vypracovat projektovou dokumentaci pro provedení stavby. Rodinný dům je navržen pro čtyřčlennou rodinu. Nachází se v okrajové části městyse Velké Němčice. Objekt je řešen jako samostatně stojící o dvou nadzemních podlažích, nepodsklepený. První nadzemní podlaží lze rozdělit na část technickou a aktivní. V technické části se nachází garáž pro jedno automobilové stání, dílna, technická místnost šatna a schodiště. V aktivní zóně domu se nachází obývací pokoj s jídelnou, kuchyní a vstup na terasu. V druhém nadzemním podlaží jsou tři pokoje, šatna koupelna, sušárna a samostatné WC. Nosné zdivo je zděné z cihelných tvárnic Porotherm. Stropy jsou z POT nosníků a stropních vložek MIAKO. Část rodinného domu je zastřešena pultovou střechou se sklonem 150 z plechové střešní krytiny Lindab a druhá část plochou střechou ze spádových klínů.The aim of this bachelor thesis which is called „ A brick – built detached house“ is to create documentation for carrying out construction. The house is designed for a four – member family. It is situated in a suburb of Velké Němčice. The building has been designed as a detached house with two floors and no basement. The first floor consists of two parts – a technical and active one. In the technical part, there is a garage for a car, workroom, technical room, closet and staircase. In the active part, there is a living room with dining room, kitchen and entrance leading to the terrace. On the second floor, there is a closet, bathroom, drying room, separate toilet and three rooms. The load – bearing wall is made of brick breeze blocks Porotherm. The ceiling is made of POT girders and ceiling inserts Miako. Part of the house is covered with a single pitch roof with an agle of inclination of 15° made of a tin roof covering Lindab and the second part is made of a flat roof from a sloped wedge.

Start acceleration of the space GPS receiver

The cold start of the space GPS receiver, i.e. thestart without any information about the receiver position, satelliteconstellation, and time, is complicated by a large Doppler shiftof a navigation signal caused by the satellite movement on theEarth orbit. That increases about five times the search space ofthe navigation signals compared to the standard GPS receiver.The paper investigates a method of the acceleration of the GPSreceiver cold start time designed for the pico- and femto-satellites.The proposed method is based on a combination of the parallelsearch in Doppler frequency and PRN codes and the serial searchin code phase delay. It can shorten the cold start time of the GPSreceiver operating on LEO orbit from about 300 to 60 secondswhile keeping the simplicity of FPGA signal processor and lowpower consumption. The developed algorithm was successfullyimplemented and tested in the piNAV GPS receiver. The energyrequired for the obtaining of the position fix was reduced fivetimes from 36 on to 7.7 Joules. This improvement enablesapplications of such receiver for the position determination insmaller satellites like Pocket Cube or femto-satellites with a lowerenergy budget than the Cube Satellite

Separation of Undesirable Materials from Biomass Prior to the Gasification Process

Import 23/07/2015Tato práce se zabývá návrhem zařízení pro separaci nežádoucího materiálu z převáděné biomasy před zplyňováním. V první části práce je uveden krátký náhled na proces zplyňování a také rešerše separačních metod používaných v tomto odvětví. Práce dále obsahuje návrh variant z nichž jedna je vyhodnocena pomocí hodnotové analýzy jako optimální. Pro tuto variantu jsou dále provedeny potřebné výpočty, vytvořen model a vypracována výkresová dokumentace za použití programu Creo 3.0. V závěru této práce jsou zhodnoceny dosažené výsledky.This thesis deals with the design of a device for separation of undesirable material from the biomass prior to gasification. The introduction includes a brief preview of the gasification process and the preliminary research of separation methods used in this field. The work also contains draft of variants of which one is evaluated using value analysis as optimal. For this variant, necessary calculations were made as wel as model and drawings which were made using Creo Parametric 3.0. In conclusion of this work, achievements are assessed.354 - Katedra robotikyvýborn

Plasma Speaker

The article describes the design and construction of one-channel plasma speaker. Absence of mechanical membrane gives the plasma speaker no frequency limitation. The design consists of power source to supply control electronic for signal modulation, converter and output transformer. Modulation of audio signal is realized by integrated circuit TL 594 that provides the PWM modulation. Duty cycle and frequency is adjusted by potentiometers. Dual forward converter is used to voltage amplification. High voltage discharge between the electrodes on the secondary winding is modulated by the PWM signal and produces sound

Java EE Organizer

Tato práce pojednává o analýze stávajících organizérů a přístupů, které jsou s těmito aplikacemi spojeny. Další část práce popisuje model třívrstvé architektury a její části. Jsou zde také popisovány některé základní technologie, které jsou obsaženy v platformě Java EE a nebo jsou s touto platformou úzce spjaty. Další část práce je věnována popisu implementace a návrhu aplikace Java EE Organizér, což je aplikace, jejímž úkolem je správa událostí, úkolů a kontaktů.This thesis analyses existing organizers and approaches associated with these applications. Next part of the work describes three tier architecture and its individual parts. It also described some of the basic technologies which are included in the Java EE platform, or which that are closely related to this platform. Last part of the work is dedicated to describing the implementation and design of Java EE Organizer. It is an application which target is administration of event, task and contact manager.