No (543)
Yes (60)
Number of found documents:
603
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Measurement of camera spectral response
Melich, Radek; Václavík, Jan; Žídek, Karel
2016 - English
Spectral response of the camera will be measured using monochromator in conjunction with an integration sphere. Camera without objective will be placed in one port of the integrating sphere and light beam from monochromator will be fed into perpendicular port. Sensor of the camera sensor will be therefore uniformly illuminated by diffused light from monochromator. Proposed FWHM of the monochromator is 15 nm as a trade-off between light intensity provided by monochromator and deformation of spectral characteristic (Picture XY). Diameter of the integrating sphere has to be larger than 100 mm to ensure uniform illumination over sensor area.
Keywords:
Camera spectral response
Available at various institutes of the ASCR
Measurement of camera spectral response
Spectral response of the camera will be measured using monochromator in conjunction with an integration sphere. Camera without objective will be placed in one port of the integrating sphere and light ...
METIS mirror M0 EQM
Lédl, Vít; Melich, Radek; Vít, Tomáš
2016 - English
Scope of the document is to provide required test results with respect to the structure of M0 mirror, EQM version. The mirror has a unique numbering M0-C09-12.
Keywords:
METIS mirror Mé EQM
Available at various institutes of the ASCR
METIS mirror M0 EQM
Scope of the document is to provide required test results with respect to the structure of M0 mirror, EQM version. The mirror has a unique numbering M0-C09-12.
Plazmové stříkání z kapalné fáze: interakce kapaliny s proudem plazmatu a vznik nástřiku
Tesař, Tomáš; Mušálek, Radek; Medřický, Jan; Lukáč, František
2016 - Czech
Plazmové stříkání z kapalné fáze je rychle se rozvíjejícím odvětvím žárového stříkání. Hybnou silou vývoje jsou unikátní vlastnosti, které vrstvy deponované z kapalné fáze nabízejí, jako je vysoká tvrdost, vysoká odolnost vůči tepelným šokům či nízká tepelná a elektrická vodivost. Klíčovým faktorem ovlivňujícím výsledný vzhled a vlastnosti vyrobeného nástřiku je zvolený vstupní materiál, kterým může být suspenze jemného prášku či roztok. Parametry dané suspenze (koncentrace pevné fáze, viskozita, povrchové napětí, chemické složení, atd.) či roztoku (zejména koncentrace) pak ovlivňují interakci s proudem plazmatu, která má na výslednou mikrostrukturu zásadní vliv. Tento příspěvek přibližuje problematiku interakce kapalného vstupního materiálu s plazmatem a ukazuje možnosti studia mechanismů růstu nástřiku. Plasma spraying from liquid feedstocks is a rapidly developing field of thermal spraying since the coatings prepared from liquids exhibit some unique features, such as high hardness, thermal shock resistance or low thermal and electric conductivity. The key factor influencing the final coating character and properties is the input material which may be in the form of a suspension or a solution. Parameters of the selected suspension (solids concentration, viscosity, surface tension, chemical composition, etc.) or solution (concentration, etc.) determine its interaction with the plasma jet which strongly influences the coating buildup. This proceeding introduces the problematics of the interaction between the liquid feedstock material with the plasma jet and presents the way of evaluation of the coating buildup.
Keywords:
suspension plasma spraying; liquid plasma interaction; atomization; coating buildup
Available at various institutes of the ASCR
Plazmové stříkání z kapalné fáze: interakce kapaliny s proudem plazmatu a vznik nástřiku
Plazmové stříkání z kapalné fáze je rychle se rozvíjejícím odvětvím žárového stříkání. Hybnou silou vývoje jsou unikátní vlastnosti, které vrstvy deponované z kapalné fáze nabízejí, jako je vysoká ...
ELECTRON BEAM REMELTING OF PLASMA SPRAYED ALUMINA COATINGS
Matějíček, Jiří; Veverka, J.; Čížek, J.; Kouřil, J.
2016 - English
Plasma sprayed alumina coatings find numerous applications in various fields, where they enhance the properties of the base material. Examples include thermal barriers, wear resistance, electrical insulation, and diffusion and corrosion barriers. A typical structure of plasma sprayed coatings, containing a multitude of voids and imperfectly bonded interfaces, gives them unique properties - particularly low thermal conductivity, high strain tolerance, etc. However, for certain applications such as permeation barriers or wear resistance, these voids may be detrimental.\nThis paper reports on the first experiments with remelting of plasma sprayed alumina coatings by electron beam technology, with the purpose of densifying the coatings and thereby eliminating the voids. Throughout the study, several parameters of the e-beam device were varied - beam current, traverse velocity and number of passes. The treated coatings were observed by light and electron microscopy and the thickness, structure and surface morphology of the remelted layer were determined and correlated with the process parameters. Based on the first series of experiments, the e-beam settings leading to dense and smooth remelted layer of sufficient thickness were obtained. In this layer, a change of phase composition and a marked increase in hardness were observed.\n
Keywords:
Plasma sprayed coating; alumina; electron beam; remelting; post-treatment
Available at various institutes of the ASCR
ELECTRON BEAM REMELTING OF PLASMA SPRAYED ALUMINA COATINGS
Plasma sprayed alumina coatings find numerous applications in various fields, where they enhance the properties of the base material. Examples include thermal barriers, wear resistance, electrical ...
Evolution of Point-To-Plane Nanosecond Discharge in Deionized Water
Šimek, Milan; Pongrác, Branislav; Člupek, Martin; Babický, Václav; Lukeš, Petr
2016 - English
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).
Keywords:
nanosecond discharge; water; ICCD imaging
Available at various institutes of the ASCR
Evolution of Point-To-Plane Nanosecond Discharge in Deionized Water
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 ...
THE INVESTIGATION OF AN Al7075 ALLOY PREPARED BY SPARK PLASMA SINTERING OF MILLED POWDERS
Molnárová, O.; Málek, P.; Nemeth, G.; Kozlík, J.; Lukáč, František; Chráska, Tomáš; Cinert, Jakub
2016 - English
Atomized powder of an Al7075 alloy was high energy ball milled at room and cryogenic temperatures and compacted by spark plasma sintering (SPS) method. The influence of processing parameters on phase composition and microstructure was studied by X-ray diffraction, light and scanning electron microscopy. The mechanical properties were characterized by microhardness measurements. The atomized powder contained a large volume fraction of intermetallic phases located predominantly in continuous layers separating cells or dendrites in the interior of individual powder particles. Consolidation by SPS destroyed partially this morphology and replaced it by individual particles located at boundaries of original powder particles, at cell boundaries or arranged in chains in previous dendritic regions. High energy milling destroyed most intermetallic particles and enriched the matrix by solute atoms. The high deformation energy introduced into the powder during milling enhanced microhardness up to 220 HV. Consolidation of milled powders by SPS led to the formation of very fine-grained structure with the grain size even below 1 μm and with the fraction of high-angle boundaries about 0.9. Two main types of heterogeneously distributed precipitates were found. The irregularly shaped precipitates with a size about 1 μm seemed to encompass areas with rod like nano-precipitates in most samples. A drop in microhardness to 118HV was observed after SPS, predominantly due to a release of introduced deformation energy.
Keywords:
Cryo-milling; Spark plasma sintering; Ultrafine-grained materials; Milling
Available at various institutes of the ASCR
THE INVESTIGATION OF AN Al7075 ALLOY PREPARED BY SPARK PLASMA SINTERING OF MILLED POWDERS
Atomized powder of an Al7075 alloy was high energy ball milled at room and cryogenic temperatures and compacted by spark plasma sintering (SPS) method. The influence of processing parameters on phase ...
ATMOSPHERIC JET BASED ON SURFACE STREAMER DIELECTRIC BARRIER DISCHARGE
Šimek, Milan; Prukner, Václav
2016 - English
We designed novel axisymmetric atmospheric jet formed by effluents produced by surface streamers suitable for various applications. Filamentary streamers are produced by the amplitude-modulated AC surface dielectric barrier discharge. The SDBD-based jet makes use of the tangential injection of the working gas into a cylindrical chamber that induces a fast vortex flow through the discharge zone and expells excited/ionized/reactive species out of the discharge area through the axial orifice in the form of a jet spinning around its axis. The jet may be easily used to treat surfaces, expose biological samples or even be injected in liquids.
Keywords:
atmospheric pressure; jet; surface barrier discharge
Available at various institutes of the ASCR
ATMOSPHERIC JET BASED ON SURFACE STREAMER DIELECTRIC BARRIER DISCHARGE
We designed novel axisymmetric atmospheric jet formed by effluents produced by surface streamers suitable for various applications. Filamentary streamers are produced by the amplitude-modulated AC ...
Návrh konceptů řešení předsádky pro zařízení OptoNS.
Pintr, Pavel
2016 - Czech
Pro vyhodnocení detailů (tvar Taylorova kuželu) využívá firma Elmarco, a. s., komerční objektiv Nikon AF Nikkor 200 mm f/4D IF-ED. Tento systém je schopen zobrazit scénu v horizontální velikosti 33 mm, případně 23 mm. Nedokáže zachytit potřebný detail. V současné době je řešeno osvětlení pomocí LED čipu na provozním světelném toku 5500 lm a difuzorem. Ke zvýšení ostrosti hran je požadováno kolimované světlo. Pozadí by mělo být co nejvíce homogenní horizontálně (podél strunové elektrody). Osvětlení by mělo být vysoké kvůli potřebě krátkého expozičního času pro monitorování rychlých dějů. The company Elmarco uses a classical commercial objective with a focal length of 200 mm for a detection of shape of Taylor´s cone. This system displays a scene with the horizontal size of 23 mm and doesn´t show a scene with a required detail. The commercial solutions don´t exist for the long working distances of 550 mm. We prepared optical solutions of conversion\nlens and the one solution of a main objective. These optical solutions should fulfill required optical parameters.
Keywords:
optical design; objective; optimization
Available at various institutes of the ASCR
Návrh konceptů řešení předsádky pro zařízení OptoNS.
Pro vyhodnocení detailů (tvar Taylorova kuželu) využívá firma Elmarco, a. s., komerční objektiv Nikon AF Nikkor 200 mm f/4D IF-ED. Tento systém je schopen zobrazit scénu v horizontální velikosti 33 ...
Konstrukce spektroskopu pro pozorování hvězdných spekter
Rail, Zdeněk; Jareš, Daniel; Pintr, Pavel; Vápenka, David
2015 - Czech
Tento článek předkládá návod na konstrukci přístroje - spektroskopu pro vizuální pozorování hvězdných spekter. K jeho stavbě je použito běžně prodávaných součástek. Samotné sestavení přístroje lze provést bez pomoci obráběcích strojů ve spartánsky vybavené dílně. This paper presents the construction list of a spectroscope for visual observation of stellar spectra. The device consists of parts easily accessible on market. Assembly of the spectroscope does not require exceptionally equipped workshop and can be made in very spartan conditions.
Keywords:
Spectrograph; Star spectral line; Newton telescope; Barlow lens; Difraction grating; Colimator lens; Toroidal lens; StarAnalyzer grating
Fulltext is available at external website.
Konstrukce spektroskopu pro pozorování hvězdných spekter
Tento článek předkládá návod na konstrukci přístroje - spektroskopu pro vizuální pozorování hvězdných spekter. K jeho stavbě je použito běžně prodávaných součástek. Samotné sestavení přístroje lze ...
Youngův modul na rozhraní elastického a elastoplastického materiálu
Kocmanová, Lenka; Haušild, P.; Materna, A.; Matějíček, Jiří
2015 - Czech
Příspěvek je zaměřený na určování Youngova modulu na ostrém rozhraní mezi dvěma materiály, kde jeden materiál je elastický a druhý elasto-plastický. K určení Youngova modulu byl použit 3D numerický model nanoindentace s kuželovým indentorem. Rozhraní mezi materiály je rovina s normálou kolmou ke směru vtisku. Cílem je simulovat spojení kovových a keramických materiálů.\nHodnoty Youngova modulu v závislosti na normované vzdálenosti od rozhraní jsou aproximovány inverzní beta distribucí a je určena závislost parametrů inverzní beta distribuce na velikost oblasti ovlivněné druhou fází. \n The paper is aimed at determining the Young's modulus at the sharp interface between two materials, where one material is elastic and the other elastic-plastic. To determine the Young's modulus was used 3D numerical model of nanoindentation with conical indenter. The interface between the materials with the normal plane perpendicular to the direction of penetration. The goal is to simulate the combination of metal and ceramic materials.\n Young modulus according to the standardized distance from the interface are approximated inverse beta distribution and is determined by the relation between parameters inverse beta distribution of the size of the area affected by the second phase
Keywords:
instrumented indentation; tungsten; steel; composites; finite element modelling
Available at various institutes of the ASCR
Youngův modul na rozhraní elastického a elastoplastického materiálu
Příspěvek je zaměřený na určování Youngova modulu na ostrém rozhraní mezi dvěma materiály, kde jeden materiál je elastický a druhý elasto-plastický. K určení Youngova modulu byl použit 3D numerický ...
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