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Comparison of hookah, electronic cigarette and classic cigarettes in regard to emitted particles
Krátký, Štěpán ; Bělka, Miloslav (referee) ; Lízal, František (advisor)
This master’s thesis is focusing on the research of chosen smoking types and their comparison in regard to emitted particles. Aerosol created during smoking represents a serious threat for human health. For purposes of this work an experimental set-up was constructed in the Laboratory of Aerosol Research at BUT FME and experiments simulating smoking process were carried out. The results of these experiments are presenting objective information about the constitution of produced aerosol which enters smoker’s lungs. There are many myths about the harmful effects of different types of smoking. The goal of this work is to verify and resolve these myths and set the foundation for possible upcoming research in this area.
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Vectorial Kerr magnetometry
Flajšman, Lukáš ; Veis,, Martin (referee) ; Urbánek, Michal (advisor)
Increased complexity of novel magnetic materials in the last decade has placed high demands on the manufacturing process as well as on the characterization. One of the possibilities for characterization of magnetic samples is to exploit the magneto-optical effects. The presented work uses the magneto-optical Kerr effect as a major characterization technique to probe the magnetic properties of samples. We have developed a mathematical model describing the effect of the magnetization on the polarized light and present an apparatus capable of measuring the response given by the light-matter interaction. The experimental results show the performance of the apparatus on the various magnetic systems including meta-stable iron layers, Stoner-Wohlfarth particles and magnetic vortices. The scanning vectorial Kerr magnetometer allowed us to probe the vector of magnetization with diffraction limited resolution below 500 nm.
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Hyperfine interactions in maghemite and magnetite particles
Křišťan, Petr ; Štěpánková, Helena (advisor) ; Procházka, Ivan (referee)
Thesis is aimed at studying of magnetic iron oxide particles of submicron and nanoscale dimensions by means of nuclear magnetic resonance (NMR). 57 Fe NMR inves- tigations were carried out in composite bentonite/maghemite with respect to tempera- ture of calcination (Tcalc) during the sample preparation and in magnetite submicron powders with respect to various range of the particles size. One of the main findings is that increasing Tcalc improves resolution in the NMR spectra, which is most likely connected with higher degree of atomic ordering in the spinel structure. Evaluating the integral intensities of NMR spectra allowed us to determine the relative content of maghemite phase in particular samples of the series: the content rapidly grows for Tcalc up to ∼420 deg. An approach to distinguish signal from tetrahedral and octahedral irons was developed and tested on pure maghemite sample. Analysis based on vacancy- distribution models was performed in the spinel structure and the results were compared to the experiment. 57 Fe NMR spectra in submicron magnetite samples were found to differ markedly from spectrum of a single crystal. It was concluded that the investigated powders possess high amount of defects in the crystal structure or contain additional phase (probably closely related to the maghemite phase).
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Measurement of spray characteristics using optical measurement methods
Ďurdina, Lukáš ; Otáhal, Jan (referee) ; Jedelský, Jan (advisor)
Diplomová práce se zabývá měřením charakteristik sprejů dvou tlakových vířivých trysek pro spalovací komoru malého turbínového motoru na zkušebním stavu za studena pomocí metod Particle Image Velocimetry (PIV) a fázové Dopplerovské anemometrie (PDA). Cílem měření bylo stanovit a porovnat charakteristiky sprejů obou trysek. Výsledky měření mají objasnit rozdílnost chování trysek za provozu a možný dopad na proces spalování. Úvodní teoretická část pojednává o základních fyzikálních principech atomizace kapalin, konstrukci a oblasti uplatnění tlakových vířivých trysek a o principech laserových diagnostických metod použitých při experimentálním měření. Nasledující část popisuje návrh a montáž zkušební trati a dalších zařízení navržených pro experimentální měření v této práci. Experimentální část se zabývá nastavením parametrů měřícího systému a zpracováním dat. Výsledky měření zahrnují vektorová rychlostní pole, axiální rychlostní profily a distribuce velikosti kapek pro různé provozní podmínky obou trysek.
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Monitoring the coefficient of light scattering on aerosol particles at the Kosetice background station
Holubová Šmejkalová, Adéla ; Zíková, Naděžda ; Ždímal, Vladimír ; Holoubek, Ivan
The direct effect of the atmospheric aerosols to radiation balance is the scattering or absorption of light on these particles. While solar radiation on aerosol particles or clouds negatively affects the radiation (resulting in cooling), absorbtion causes increasing of the ambient air temperature. Contribution to the study of the effect of aerosol particles on the climate, a measurement of the coefficient of light scattering is carry out at the Kosetice background station. The Integrating Nefelometer measures at 3-wavelength (RGB) forward and back light scattering. The values of the scattering coefficient at 550 nm (green) are typically high in the cold part of the year, reflecting both increased concentrations of pollutants and stable atmospheric conditions. Daily variability is the smallest in summer (varies between 25 and 18 Mm-1), the most noticeable daily variation is observed in the spring, when stable values 44 Mm-1 drop after noon to 26 Mm-1. The calculation of Ångström's exponent showed that in the summer, the fine fraction dominates in the sampled air.
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Seasonal Differences in Volatility of Atmospheric Aerosol at a rural measurement site Košetice.
Kubelová, Lucie ; Vodička, Petr ; Makeš, Otakar ; Zíková, Naděžda ; Ondráček, Jakub ; Schwarz, Jaroslav ; Ždímal, Vladimír
Volatility is an important characteristics of atmospheric aerosol because it affects formation, conversion and removal of aerosol particles. This study deals with differences in volatility of atmospheric aerosol at rural measurement site Košetice. Analyzes are based on high-time measurements of atmospheric aerosol, including an aerosol mass spectrometer and a scanning mobility particle sizer. Not only the time variation of mass concentration, but also the daily course of pollutants and the influence of meteorological conditions are discussed.
Fulltext: content.csg -  PDF
Plný tet: SKMBT_22317041913181 - PDF
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Calibration and Exact Characterization of Aerosol Deposit colected by SDI Impactor
Havránek, Vladimír
Ion beam analytical methods as PIXE (Particle induced X-ray emission), PIGE (Particle induced gamma-ray emission) and RBS (Rutherford backscattering spectrometry) are frequently used for elemental analysis of different types of atmospheric aerosol samples in a form of aerosol deposits on thin plastic filters or foils (Alfassi and Peisach, 1991, Johansson and Campbell, 1988). An ideal sample for analysis is thin homogeneous aerosol deposit with known deposit area. However in practice such samples are rare. They are often thick (more than limit for thin target approximation i.e. larger then few hundred micrograms per square centimetres), of irregular shape and unknown deposit area. In such conditions all obtained elemental mass results should be corrected for apparent deposit thickness, deposit homogeneity and effective deposit area.
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