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Multi-frequency research of symbiotic binaries
Merc, Jaroslav ; Wolf, Marek (advisor) ; Hambálek, Ľubomír (referee) ; Mikulášek, Zdeněk (referee)
Symbiotic stars are among the widest interacting binaries. They consist of a late-type, cool giant and a hot component, which is typ- ically a white dwarf or in a few cases a neutron star. The presented thesis summarizes all the relevant information on the symbiotic bi- naries, including both components of systems, their activity, and other manifestations of variability. Symbiotic systems are presented as unique astrophysical laboratories in the study of stellar evolution, mass transfer and its accretion, stellar winds, jets, and other physical processes. A part of the thesis presents the New Online Database of Sym- biotic Variables, a modern, complex, and most up-to-date catalog of these binaries that currently contains more than 1 000 objects in the Milky Way and another 16 galaxies. At the same time, the Database constitutes the most comprehensive collection of orbital, stellar, and observational parameters of all known symbiotic binaries. These data are studied in detail in order to better understand the symbiotic pop- ulation. From the Database, poorly characterized symbiotic candidates have been selected and studied on the basis of new and archival ob- servational data and information from the literature. A substantial sample of 47 symbiotic candidates from the literature and 3 newly...
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The light-curve solution of an eclipsing binary
Procházka, Ondřej ; Zasche, Petr (advisor) ; Wolf, Marek (referee)
The main aim of this work was the first detailed analysis of an eclipsing binary system V641 Aur. The complete light curve of this binary was obtained in three photometric filters, which were analyzed with the program PHOEBE. It is a double star with the orbital period of about 0.50487 day, whose both components are rather similar. Their individual spectral types are probably F6 and F8 (according to the temperatures), or F6 and F6 (as derived from masses). Both are orbiting on a circular orbit and despite their short period the system is a detached one and both components are still located on the main sequence. Moreover, thanks to the asymmetry of the light curve there was discovered a spot on the surface of the primary component, and the third light was not detected. For more detailed analysis higher accuracy of photometry and spectroscopy data are required.
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The light curves of eclipsing binaries
Korda, David ; Zasche, Petr (advisor) ; Wolf, Marek (referee)
New CCD photometric observations of ten short-period LMB (Low Mass Binaries) were carried out. Data were obtained using 65 cm telescope in Ondřejov in the filters I, R and V from 2014 to 2016. Light curves were analysed using the program PHOEBE. The obtained masses and radii of the stars were compared with the theoretical mass-radii relation. There arises that the short-period binaries have the radii of about 4 % larger than the theoretical prediction from the stellar evolution models. Powered by TCPDF (www.tcpdf.org)
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Technology of pouring LED strips with epoxy materials
Rudy, Veronika ; Krejčí, Miroslav (referee) ; Píška, Miroslav (advisor)
The thesis deals with the pouring of epoxy materials over LED strips. The research part contains an introduction to photometry and summarizes the types of potting compounds along with their characteristics. The practical part delves into the effect different amount of pigment has on the photometric properties. This is assessed based on verified measurements performed with the help of a goniophotometer on samples with different amounts of pigment, which were created using an integration sphere. Furthermore, a brightness analysis and a long-term outdoor test were performed.
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The light curves of eclipsing binaries
Korda, David ; Zasche, Petr (advisor)
New CCD photometric observations of ten short-period LMB (Low Mass Binaries) were carried out. Data were obtained using 65 cm telescope in Ondrejov in the filters I, R and V from 2014 to 2016. Light curves were analysed using the program PHOEBE. The obtained masses and radii of the stars were compared with the theoretical mass-radii relation. There arises that the short-period binaries have the radii of about 4 % larger than the theoretical prediction from the stellar evolution models. 1
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Problems of the mirror shutter in the LED module of the headlight
Ettler, Jan ; Hlaváček, Martin (referee) ; Kalivoda, Milan (advisor)
This bachelor thesis deals with methods of attaching the mirror shutter in LED modules in headlamps. The aim is to compare three methods of attachment which are used in one of the platform variants. The following are the methods of attachment, followed by the description of the light sources and functions of the LED modules; they are: riveting, hot stamping and fixation with clips. Risk associated with the assembly of mirror shutter into the light source are analysed via FMEA analysis, including also measures and actions for risk reduction – implementation of lighting of produced light sources in a special jig in the light laboratory. Vibrations tests were carried out to find out the influence of vibration on the mirror shutter in LED modules in the traffic. The tests revealed that even if the clip is incorrectly fixed (not attached to the end position) it does not affect the functionality of the module.
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The Uncertainty Of Measurement In Lightlaboratory
Motyčka, Martin
This article has task to inform a reader of uncertainties of measurement in laboratory of light. In the first part there are mathematical descriptions of different types of uncertainties, including the methodology for their determination. The second part is focused in detailed description of standard uncertainties for measurement of the luminous flux, luminous intensity distribution and spectral power distribution. The last section provides practical calculations and results of standard uncertainties as an integral value or wavelength function.
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Industrial Tester for Photometric Values of LED diodes Used in Automotive Signal Lighting
Gaži, Dominik ; Froehling, Kenneth (referee) ; Baumgartnerová, Alena (advisor)
V posledních letech zažili světlomety v autech obrovský technický rozvoj, který se podílel na jejich současné složitosti. Aby řidiči i zákazníci byli spokojeni, je využíváno různých technologií pro neustálé dosahování účinnějších a bezpečnějších světelných zdrojů. Společnosti usilují o minimalizaci ztrát ve výrobě ve snaze šetřit životní prostředí a konat ekonomicky. Tato práce se zabývá výzkumem osvětlovací techniky a návrhem jednoduchého a efektivního zařízení pro testovaní chyb LED plošných obvodů ve světlometech, to vše za účelem minimalizace strat. Dalším cílem je výzkum možností konstrukce takového zařízení z technologického hlediska.
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