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Corrosion behavior of plasma coatings CuAl10 and CuAl50 on magnesium alloy AZ 91
Kubatík, Tomáš František; Stoulil, J.; Stehlíková, K.; Slepička, P.; Janata, Marek
2016 - English
The most common magnesium alloy AZ 91 is widely used as a structural material, but its use is limited at higher temperatures and high humidity. Plasma spraying is a technology that allows to prepare protective metallic and non-metallic coatings on a wide variety of substrates including magnesium and its alloys. In this study, CuAl10 and CuAl50 were plasma sprayed on magnesium alloy AZ 91 with the aim to study corrosion resistance of the plasma sprayed coatings. The corrosion resistance of layers was evaluated by the method of electrochemical potentiodynamic measurement as well as long-term corrosion tests in a condensation chamber with 0.5 mol\nNaCl at the temperature of 35 °C for 1344 hours. Layers with 1, 2, 5 passes and passes of CuAl10 with the thickness ranging from 75 to 716 mm and CuAl50 with the thickness ranging from 64 to 566 mm were prepared. The increased corrosion velocity was observed in the case of thin layers of 2 and 5 passes due to the development of a galvanic corrosion couple. The CuAl10 layer prepared with ten passes has an outstanding corrosion resistance.
Keywords:
magnesium alloy AZ 91; plasma spraying; corrosion resistance
Available at various institutes of the ASCR
Corrosion behavior of plasma coatings CuAl10 and CuAl50 on magnesium alloy AZ 91
The most common magnesium alloy AZ 91 is widely used as a structural material, but its use is limited at higher temperatures and high humidity. Plasma spraying is a technology that allows to prepare ...
Deposition of Titania from Solution by Hybrid Water-Stabilized Plasma Torch
Mušálek, Radek; Medřický, Jan; Tesař, Tomáš; Kotlan, Jiří; Lukáč, František
2016 - English
Thermal spraying with liquid feedstock presents a novel route for deposition of functional coatings. In this study, possibility of preparation of titania coatings from solution by hybrid water stabilized plasma torch is presented. Coatings were prepared from solution of titanium isopropoxide Ti[OCH(CH3)2]4 in anhydrous ethanol. Fragmentation of feedstock stream in the plasma jet was monitored by shadowgraphy. Deposition was carried out on steel samples mounted to the cooled rotating carousel. Cross-sectional images from SEM microscope showed successful formation of the deposit with dual morphology consisting of fine feather-like features combined with bigger droplets. X-ray diffraction revealed formation of nanometric rutile crystallites.
Keywords:
Thermal spraying; plasma spraying; titania; solution; liquid feedstock
Available at various institutes of the ASCR
Deposition of Titania from Solution by Hybrid Water-Stabilized Plasma Torch
Thermal spraying with liquid feedstock presents a novel route for deposition of functional coatings. In this study, possibility of preparation of titania coatings from solution by hybrid water ...
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
2016 - English
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
Keywords:
cold air plasma; plasma activated water; sublethal injury; lipoperoxidation
Available at various institutes of the ASCR
Formation of RONS in cold air plasma activazed water and their effects on cell membranes of Escherichia coli
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. ...
DYNAMICS OF ACCELERATING STREAMER IN BARRIER DISCHARGE IN AIR.
Hoder, T.; Bonaventura, Z.; Prukner, Václav; Šimek, Milan
2016 - English
An accelerating streamer in barrier discharge is generated in 10 torr pressure air. Using the complex voltage waveform, the stable and reproducible discharge is triggered. From the ratio of two spectral bands of molecular nitrogen the electric field is determined in 2D. These results are well resolved in time and space thus suitable as a benchmark for computation of the streamer initiated plasma-chemistry in air.
Keywords:
streamer; air; electric field
Available at various institutes of the ASCR
DYNAMICS OF ACCELERATING STREAMER IN BARRIER DISCHARGE IN AIR.
An accelerating streamer in barrier discharge is generated in 10 torr pressure air. Using the complex voltage waveform, the stable and reproducible discharge is triggered. From the ratio of two ...
Sférochromatické vada Clarkova objektivu z observatoře v Ondřejově
Rail, Zdeněk; Šrajer, Bohdan; Jareš, Daniel; Vápenka, David; Pintr, Pavel
2016 - Czech
V naší práci jsou předloženy výsledky matematické simulace zbytkových vad Clarkova objektivu o průměru 8 palců (203.2 mm). Tento achromatický dublet je používán na observatoři v Ondřejově více než 100 let k pozorování Slunce. In our paper the results of mathematical simulations of the residual aberrations of Clark‘s 8 inch (diameter 203.2 mm) objective lens are presented. This achromatic dublet has been used at the Ondřejov Observatory for more than 100 years mostly for solar observation.
Keywords:
Alvan Clark doublet; Achromatic objective; Spherochromatic aberration; Longitudal chromatic aberration; Dispersion curve; Non aplanatic dublet; Spotdiagrams; Solar photosphere photography; Ondrejov observatory
Available at various institutes of the ASCR
Sférochromatické vada Clarkova objektivu z observatoře v Ondřejově
V naší práci jsou předloženy výsledky matematické simulace zbytkových vad Clarkova objektivu o průměru 8 palců (203.2 mm). Tento achromatický dublet je používán na observatoři v Ondřejově více než 100 ...
Arc–Anode Attachment Area in DC Arc Plasma Torch at Low Pressure
Ondáč, Peter; Mašláni, Alan; Hrabovský, Milan
2016 - English
Studying the processes in the anode attachment area of a DC arc plasma torch helps to extend the lifetime of the anode, stabilize the plasma flow for plasma spraying and better understand the movement of the anode attachment. In this work, such processes were studied at low pressure, by a non-disturbing method, using a high-speed camera and a high voltage probe. We also found pressure ranges, in which the following transitions were observed: the constricted/diffuse anode attachment, and subsonic/supersonic plasma jet\n
Keywords:
Arc Plasma Torch; Arc–Anode Attachment; Low Pressure
Available at various institutes of the ASCR
Arc–Anode Attachment Area in DC Arc Plasma Torch at Low Pressure
Studying the processes in the anode attachment area of a DC arc plasma torch helps to extend the lifetime of the anode, stabilize the plasma flow for plasma spraying and better understand the movement ...
Fyzikálně astronomické úvahy II.
Oupický, Pavel
2016 - Czech
Referát je zaměřen na problematické oblasti fyziky a astronomie.\nV loňském roce jsem se pokusil o pár úvah o fyzikálně astronomických problémech (dále FAU I.), v nichž jsem neměl jasno a nebo naopak jsem si myslel, že v nich jasno mám .. v ničem jsem si ale moc jistý nebyl a zvláště u některých problémů mi bylo jasné, že některé moje úvahy mohou být jak se říká vedle .. a to byla jedna z motivací, která mne dovedla k tomuto pokračování .. v něčem zde budu pokračovat, něco korigovat a snad se mezi tím objeví i něco nového a zajímavého . Tentokrát se hodlám zabývat následujícími problematickými oblastmi fyziky a astronomie. Paper is oriented on the problem parts of physic and astronomy .\nLast year I tried a few considerations about the physical astronomical problems (the FAU I.) in which I did not have a clear or vice versa, I think that they clearly have .. in anything but I'm not too sure, especially with some of the problems was clear to me that some of my comments may be next as they say .. and it was one of the motivations that led me to this sequel .. something i will continue here, something correct and perhaps in between appear as something new and interesting. This time I am going to deal with the following areas of concern of physics and astronomy.
Keywords:
Fields; gravitation; red and blue shift; move and speed of light etc
Available at various institutes of the ASCR
Fyzikálně astronomické úvahy II.
Referát je zaměřen na problematické oblasti fyziky a astronomie.\nV loňském roce jsem se pokusil o pár úvah o fyzikálně astronomických problémech (dále FAU I.), v nichž jsem neměl jasno a nebo naopak ...
Infrared measurements in medium and long wavelength on COMPASS
Vondráček, Petr; Horáček, Jan; Pánek, Radomír; Gauthier, E.
2016 - English
The experimental study of radial profiles of parallel heat flux in the scrape-off layer (SOL) of the COMPASS tokamak shows a systematic discrepancy between medium (MWIR) and long (LWIR) wavelength infrared (IR) thermographic measurements. Significant temperature and heat flux overestimation is observed in the MWIR range, whilst the LWIR range is almost not affected. It is assumed to be caused by a presence of dust particles creating sub-pixel sized micro hot-spots. Significant inhomogeneity of the surface conditions across the limiter is observed, resulting in local disturbance of the derived heat flux profiles (decay length variation up to ~ few tens of percent). Influence of the inhomogeneously distributed micro hot-spots is suppressed using correction factors (the heat transmission coefficient α) for each pixel separately in the heat flux calculation. Procedure of the α coefficient estimation is described.
Keywords:
IR; MWIR; LWIR; Dust; COMPASS; SOL
Available at various institutes of the ASCR
Infrared measurements in medium and long wavelength on COMPASS
The experimental study of radial profiles of parallel heat flux in the scrape-off layer (SOL) of the COMPASS tokamak shows a systematic discrepancy between medium (MWIR) and long (LWIR) wavelength ...
Katadioptrický systém G.M.Popova Hvězdárny v Úpici
Rail, Zdeněk; Melich, Zbyněk
2016 - Czech
V šedesátých letech 20. století byla navržena řada dvojzrcadlových katadioptrických dalekohledů, využívajících korekčních čoček, umístěných před jejich sekundárem. Jedním z prvních návrhářů těchto přístrojů byl P.P. Argunov. Jeho návrhy byly dále rozvíjeny G.M. Popovem, J. Klevcovem a dalšími optiky. V roce 2005 byl takový dalekohled Popova o průměru 305 mm vyroben ve Vývojové optické dílně AV ČR v Turnově (dnes Ústav fyziky plazmatu AV ČR,v.v.i.-Toptec). Přístroj měl nahradit starší dalekohled Maksutov-Cassegrain o průměru 260 mm hvězdárny v Úpici, který bylo nutné zrekonstruovat. V referátu prezentujeme optický návrh systému Popova Hvězdárny v Úpici a porovnáváme jej s ekvivalentním komerčním dalekohledem typu SchmidtCassegraina a dalšími přístroji.\n\n\n During the Sixties of the Twentieth Century series of two-mirror catadioptric telescopes were designed with a correcting lens in front of their secondary mirror. One of the first designers of these devices was P.P. Argunov. His optical designs were further developed by G.M. Popov, J. Klevcov and other opticians. In 2005 one telescope of a Popov system of diameter 305 mm was manufactured in the Development Optical Workshop of Academy of Sciences of Czech Republic /now Institute of Plasma Physics of AS CR,v.v.i.-Toptec/ in Turnov. The telescope was intended to substitute an older Maksutov-Cassegrain telescope of diameter of 260 mm of the Observatory in Úpice which required the reconstruction. In this paper we present an optical design of the Popov´s system of the Observatory in Úpice and compare it with an equal commercial Schmidt-Cassegrain telescope and further devices.\n
Keywords:
Cathadioptric system; Spherical surfaces; Meniscus corrector; Residual aberrations; Spherochromatism; Coma; Astigmatism; Field curvature; Aplanatic system
Available at various institutes of the ASCR
Katadioptrický systém G.M.Popova Hvězdárny v Úpici
V šedesátých letech 20. století byla navržena řada dvojzrcadlových katadioptrických dalekohledů, využívajících korekčních čoček, umístěných před jejich sekundárem. Jedním z prvních návrhářů těchto ...
Photocatalytic Decomposition of Wastewater from the Production of Explosives
Brom, Petr; Brožek, Vlastimil; Březina, Václav; Hlína, Michal; Mastný, L.; Novák, M.
2016 - English
Water stabilized plasma generator WSP® H-500, operating on the principle of Gerdien arc was used for the photocatalytic decomposition of furazan- and picraminate-based explosives. The generator emits intensive radiation in the range of 300-660 nm, which allows not only to activate photocatalysts based on TiO2, but also other semiconductor oxides with a narrower band gap, such as tungsten oxide. The photocatalytic decomposition of sewage and slurries containing the potassium salt of 4-hydroxy-4,6-dihydro-5,7- dinitrobenzofurazane-3-oxide (KDNBF) or sodium picraminate (NaC6H4N3O5) was performed using the anatase paste and newly developed photocatalyst produced by the company Precheza a.s. The photocatalytic reactor was built using a quartz tube coil with an internal volume of 650 ml, with a nominal size of the irradiated area of 7.5 dm2 (value reduced by the area of the gaps between coil turns) to enable the flow the processing solution or suspension of up to 10 l / min. The centre of the coil is exposed to the plasma jet with the intensity\nof 80 kW; of which 15 kW is transformed into the light radiation. 11% of the radiation output was used for the presented experiments. The time of exposition was 45 mins and 20 l of solution were treated. In the case of KDNBF, 90% of the compound was decomposed. Moreover, 100% of sodium picraminate were decomposed after 15 minutes into low-molecular inorganic compounds. Advantage of the assembly is the ability to treat highly dangerous chemical compounds in a closed cycle and test selective catalyst
Keywords:
plasma generator; photocatalytic decomposition; sodium picraminate; dinitrobenzofurazane
Available at various institutes of the ASCR
Photocatalytic Decomposition of Wastewater from the Production of Explosives
Water stabilized plasma generator WSP® H-500, operating on the principle of Gerdien arc was used for the photocatalytic decomposition of furazan- and picraminate-based explosives. The generator emits ...
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