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Formation of RONS in cold air plasma activazed water and their effects on cell membranes of Escherichia coli
Tarabová, B. ; Machala, Z. ; Doležalová, Eva ; Lukeš, Petr
In this work, we focused on the detection of secondary reactive oxygen and nitrogen species (RONS) formed by cold plasma induced gas-liquid chemistry in air discharge activated water and liquids. Plasma induced chemical changes in plasma activated water (PAW) were correlated with the antibacterial effect, sublethal injury of bacterial cells and peroxidation of membrane lipids. The contribution of the electric field induced by the plasma treatment was evaluated by the detection of membrane permeabilization. The bactericidal effects of direct (plasma and PAW) and indirect (only PAW) treatments were compared with long-term preservation of the PAW with its antibacterial properties
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Evolution of Point-To-Plane Nanosecond Discharge in Deionized Water
Šimek, Milan ; Pongrác, Branislav ; Člupek, Martin ; Babický, Václav ; Lukeš, Petr
We employed techniques of time-resolved ICCD microscopy and spectroscopy to register basic morphologic and emission fingerprints of micro-discharges produced in deionized water. Fast risetime high-voltage pulses (duration of 5 ns and amplitude of ~110 kV) applied in a point-to-plane electrode geometry produced micro-discharges either periodically or in a single-shot regime. Time resolved ICCD images evidence typical streamer-like branched filamentary morphology while emission spectra show a broad-band continuum evolving during the first few nanoseconds followed by the well-known HI/OI atomic lines (tens of ns).
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Turistická chata pod Kozlenou
Lukeš, Petr ; Karlík, Štěpán (oponent) ; Lavický, Miloš (vedoucí práce)
Cílem bakalářské práce je návrh Horské chaty pod Kozlenou v obci Staré Hamry. Objekt je umístěn na svažité parcele nacházející se pod travnatým hřebenem v turisticky atraktivní oblasti Moravskoslezských Beskyd. Řešený objekt je dvoupodlažní, částečně podsklepený. V prvním nadzemním podlaží se nachází restaurace s terasou a zázemí personálu. Ve druhém nadzemním podlaží jsou umístěny pokoje pro hosty. Konstrukční systém je zděný z betonových skořepinových tvárnic. Střecha chaty je pultová.
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Dynamics of cavitation induced by focused tandem shock waves in water
Hoffer, Petr ; Šunka, Pavel ; Lukeš, Petr
Cavitation associated with the generation of shock waves in water was examined. To study these processes, a tandem shock wave generator, which generates two cylindrical pressure waves focused by a metallic parabolic reflector to a common focal region, was developed. The temporal evolution of cavitation generated by shock waves at the focal region was determined experimentally using high-temporal-resolution microphotography for a certain time delay between the first and second shock waves. Observation of the focal area also showed jetting cavitation bubbles with diameters of 100 m without presence of any rigid boundary. A theoretical model that provides analytical expressions for the temporal evolution of the pressure inside the cavitation bubbles and parameters of the pressure waveform of the second shock wave at the focal area was used to improve the same measurement by PVDF sensor gauges. On the basis of this model, the amplitudes of the compression and rarefaction parts
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Potentials of the hyperspectral remote sensing - Aisa Eagle system and future perspectives
Lukeš, Petr ; Hanuš, Jan ; Kaplan, Věroslav ; Zemek, František
Since 2004 the Global Change Research Centre (CVGZ) operates a hyperspectral airborne imaging system AISA Eagle. A basic introduction to hyperspectral remote sensing and its potential applications in science as well as for commercial and military uses are presented, followed by a description of the system together with an overview of the key data pre-processing steps. The application of a rapidly developing technology, hyperspectral remote sensing, is presented within the field of quantitative remote sensing of plant health status. Finally, the future development of hyperspectral remote sensing at the CVGZ is outlined.
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Individual tree crowns delineation using local maxima approach and seeded region growing technique
Novotný, Jan ; Hanuš, Jan ; Lukeš, Petr ; Kaplan, Věroslav
Remote sensing applications in forestry can profit from a rapid development of optical sensors. Applied algorithms should be suited to the new properties of the data (very high resolution and wide spectral range). Segmentation of the image into objects is an important task in forestry applications of optical remote sensing. Segmentation of individual tree crowns involves two parts — detection and delineation phase. Local maxima approach and seeded region growing technique are presented as the key concepts. Furthermore improvements, namely histogram equalization and Voronoi diagram, are incorporated. Two datasets were processed and results of the segmentation are presented. Hyperspectral data with spatial resolution of 0.8m were found as a suitable for segmentation process with 84% and 78% accuracy of detection phase and 64% and 52% accuracy in delineation phase respectively. Finally discussion of recommended settings in the algorithm is presented.
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Role of UV radiation, solution conductivity and pulse repetition frequency in the bactericidal effects during pulse corona discharge in water
Špetlíková, E. ; Janda, V. ; Lukeš, Petr ; Člupek, Martin
Inactivation of bacteria Escherichia coli and Enterococcus faecalis by the pulsed corona discharge in liquid phase has been investigated. The reactor with point to plate geometry of electrodes was used for generation of the discharge in liquid phase. The effects of the solution conductivity and the pulse repetition frequency on the bacterial inactivation have been determined. Better efficiency of inactivation was observed for both types of bacteria with the increasing solution conductivity and the pulse repetition frequency since E. faecalis was more sensitive to these changes then E. coli. The role of UV radiation emitted by the electrical discharge in the overall bacterial efficiency was evaluated in dependence on the solution conductivity using UV light transparent spectrometric cell. It was determined that UV radiation contributes about 40% to the overall inactivation of bacteria by the discharge.
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