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Surface profilometry by digital holography
Psota, Pavel; Lédl, Vít; Kaván, František; Matoušek, O.; Mokrý, P.
2017 - English
This paper presents newly developed method for measurement of surface topography based on frequency scanning digital holography. Digital holography allows for direct computation of the phase field of the wavefront scattered by an object. A tuning of the light source optical frequency results in linear phase variation with respect to the optical frequency. Slope of the linear function in every single pixel corresponds to absolute measurement of optical path difference and thus topography map of the surface can be retrieved. Principle of this contactless method is introduced and experimentally verified. The method can be used for measurement of complex geometries of common manufacturing parts as well as for topography measurement of complex composite structures, and active acoustic metasurfaces.
Keywords:
Surface profilometry; Digital holography; Frequency scanning; Absolute measurement
Available at various institutes of the ASCR
Surface profilometry by digital holography
This paper presents newly developed method for measurement of surface topography based on frequency scanning digital holography. Digital holography allows for direct computation of the phase field of ...
Mechanical properties of plasma sprayed layers of NiAl10 and NiAl40 on AZ91 alloy
Kubatík, Tomáš František; Brodil, R.; Ctibor, Pavel; Průša, F.; Brožek, Vlastimil
2017 - English
In this work, plasma coatings of NiAl10 and NiAl40 on magnesium alloy AZ91 substrate were prepared by the hybrid plasma spraying system WSP®-H 500. The both plasma sprayed coatings of NiAl10 and NiAl40 have metallurgical bond. The thicknesses of microstructures in the cross-section of NiAl10 and NiAl40 plasma sprayed coatings prepared by 9 passes were 374 and 440 μm respectively. Adhesion test of plasma sprayed layers was performed using a modified ASTM C 633 standard. The tensile adhesion strength values are 24.7 MPa for NiAl10 coatings and 12.3 MPa for NiAl40 coatings. Abrasion resistance according to Slurry Abrasion Response (SAR) test of NiAl40 layers had similar values (0.12 g/cm2)in a comparison with the uncoated AZ91 (0.126 g/cm2). Layers NiAl10 had greater weight losses (0.175 g/cm2) than uncoated AZ91. Microhardness of plasma coating of NiAl40 is several times greater than microhardnesses of plasma coating of NiAl10 and uncoated substrate AZ91
Keywords:
Adhesion strength; Nickel alloys; Plasma spraying; Wear resistance
Available at various institutes of the ASCR
Mechanical properties of plasma sprayed layers of NiAl10 and NiAl40 on AZ91 alloy
In this work, plasma coatings of NiAl10 and NiAl40 on magnesium alloy AZ91 substrate were prepared by the hybrid plasma spraying system WSP®-H 500. The both plasma sprayed coatings of NiAl10 and ...
Microwave reflectometry for density profile and turbulence measurements on the COMPASS tokamak.
Bogár, Ondrej; Bílková, Petra; Böhm, Petr; Hron, Martin; Pánek, Radomír; Silva, A.; Zajac, Jaromír; Varavin, Mykyta
2017 - English
Microwave reflectometry is an established radar technique to acquire various scientific results in plasma fusion research. Fast electron density profile measurements are crucial for the study of fusion plasmas and the operation of fusion devices. Operation capability and first results of the reflectometry on the COMPASS tokamak are presented in this contribution.
Keywords:
plasma; tokamak; COMPASS
Fulltext is available at external website.
Microwave reflectometry for density profile and turbulence measurements on the COMPASS tokamak.
Microwave reflectometry is an established radar technique to acquire various scientific results in plasma fusion research. Fast electron density profile measurements are crucial for the study of ...
Large displacement and deformation measurement by frequency sweeping digital holography
Psota, P.; Lédl, Vít; Kaván, František; Matoušek, O.; Doleček, R.
2017 - English
Recently, a digital holographic method called Frequency Sweeping Digital Holography (FSDH) for high precision measurements of surface topography of mechanical parts has been introduced. The greatest advantage of the presented FSDH is the fact that the measurement is absolute. i.e. optical path difference is independently retrieved in every single pixel. This approach can therefore be used also for measurement of large displacements and deformation. FSDH is particularly suitable in cases where the common digital holographic methods fail due to e.g. 2π unambiguity problem or speckle decorrelation. Measurement method principles, setup details, an some features of the method are discussed.\n
Keywords:
Digital holography; Digital holographic interferometry; Displacement measurement; Absolute measurements
Available at various institutes of the ASCR
Large displacement and deformation measurement by frequency sweeping digital holography
Recently, a digital holographic method called Frequency Sweeping Digital Holography (FSDH) for high precision measurements of surface topography of mechanical parts has been introduced. The greatest ...
Black Chromia Plating for the Solar Radiation Absorbers
Brožek, Vlastimil; Březina, Václav; Brom, Petr; Kubatík, Tomáš František; Vilémová, Monika; Mastný, L.; Novák, M.
2016 - English
Black chromia layers were produced on copper, zirconium and aluminium substrates. These layers are aimed to serve as solar collectors. Efficiency of the layers during UV-VIS, UV radiation and WSP® plasma torch radiation is described. The chromia layers were prepared by a new procedure, i.e. deposition of ammonium dichromate solution using plasma torch or so called Liquid Precursor Plasma Spraying (LPPS). Solution of ammonium dichromate is fed into plasma stream, where dissociation takes place under temperatures of 4000 K – 25000 K. Up to nanometric oxide particles can be produced; the resulting size is dependent on solution concentration and feeding nozzle diameter. The particles impact on substrate and form coating. Using 2 wt.% to 5 wt.% solution of ammonium dichromate and feeding nozzle of 0.2 mm in diameter is the size of produced chromia particles about 6 µm which results in formation of 2 µm to 3 µm thick coating, i.e. according to the theory an optimal thickness 2.5 um for absorption layers, necessary condition for formation energy traps for IR radiation emitters up to 100°C. Moreover, black chromia coating is a suitable corrosion barrier of metallic substrates. \n\n
Keywords:
Solar collector; black chromia; plasma spraying; ceramic coatings
Available at various institutes of the ASCR
Black Chromia Plating for the Solar Radiation Absorbers
Black chromia layers were produced on copper, zirconium and aluminium substrates. These layers are aimed to serve as solar collectors. Efficiency of the layers during UV-VIS, UV radiation and WSP® ...
Black Chromia Coatings on Metal Tubes for the Solar Collectors
Brožek, V.; Mastný, L.; Novák, M.; Vilémová, Monika; Kubatík, Tomáš František
2016 - English
This paper describes the results of the first phase of the study preparation, structure and properties of coatings modification of black chromium oxide on copper, aluminium, iron and zirconium tubes for solar collectors. The coatings are prepared by plasma spraying of liquid chromate method which is known as liquid precursor plasma spraying. Coatings have the function of an energy trap for thermal radiation wavelengths of 1 μm – 3 μm i.e. in the IR region. At the same time, the coating increases the corrosion resistance of metal substrates. The nanometric structure and thickness of the coating depend of the feeding distance and the concentration of chromate precursors. For the deposition of nanometric splats of melt chromiumIII oxide, a new type of feeder that injects precursors into the water stabilized thermal plasma produced by the WSP® generator has been\ndeveloped.\n
Keywords:
Solar collector; black chromia; plasma spraying; suspension spraying
Available at various institutes of the ASCR
Black Chromia Coatings on Metal Tubes for the Solar Collectors
This paper describes the results of the first phase of the study preparation, structure and properties of coatings modification of black chromium oxide on copper, aluminium, iron and zirconium tubes ...
Spectroscopic Study of Underwater Electrical Discharge Generated by Nanosecond Pulses.
Pongrác, Branislav; Šimek, Milan; Babický, Václav; Člupek, Martin; Lukeš, Petr
2016 - English
Underwater electrical discharge generated by high voltage pulses with nanosecond duration (~110 kV amplitude on the needle, ~5 ns duration (FWHM), 1 Hz repetition rate) has been investigated. Time–resolved optical emission spectroscopy showed different emission spectra profile of the ns–pulsed discharge compared to the μs–pulsed discharges investigated previously. Some characteristic peaks typical for water discharges (Hα, OI) were clearly visible in the spectra. In addition, the integral light emission of the discharge was recorded by photomultiplier tube.
Keywords:
nanosecond discharge; water discharge; time-resolved emission spectroscopy
Available at various institutes of the ASCR
Spectroscopic Study of Underwater Electrical Discharge Generated by Nanosecond Pulses.
Underwater electrical discharge generated by high voltage pulses with nanosecond duration (~110 kV amplitude on the needle, ~5 ns duration (FWHM), 1 Hz repetition rate) has been investigated. ...
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. ...
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