Number of found documents: 14440
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Paleomagnetic research of the fill in the Kalacka Cave, Poland. Final report. Catalogue of primary paleomagnetic data.
Pruner, Petr; Čížková, Kristýna; Kdýr, Šimon
2017 - English
Keywords: palaeomagnetism; caves; Kalacka Cave, Poland Available at various institutes of the ASCR
Paleomagnetic research of the fill in the Kalacka Cave, Poland. Final report. Catalogue of primary paleomagnetic data.

Pruner, Petr; Čížková, Kristýna; Kdýr, Šimon
Geologický ústav, 2017

Nanopatterning of Silicon Nitride Membranes
Matějka, Milan; Krátký, Stanislav; Řiháček, Tomáš; Kolařík, Vladimír; Chlumská, Jana; Urbánek, Michal
2017 - English
Membranes are typically created by a thin silicon nitride (SIN) layer deposited on a silicon wafer. Both, top and bottom side of the wafer is covered by a thin layer of the silicon nitride. The principle of silicon nitride membranes preparation is based on the wet anisotropic etching of the bottom side of the silicon wafer with crystallographic orientation (100). While the basic procedure for the preparation of such membranes is well known, the nano patterning of thin membranes presents quite important challenges. This is partially due to the mechanical stress which is typically presented within such membranes. The resolution requirements of the\nmembrane patterning have gradually increased. Advanced lithographic techniques and etching procedures had to be developed. This paper summarizes theoretical aspects, technological issues and achieved results. The application potential of silicon nitride membranes as a base for multifunctional micro system (MMS) is also\ndiscussed. Keywords: e-beam writer; silicon nitride membranes; nano patterning; anisotropic etching Available at various institutes of the ASCR
Nanopatterning of Silicon Nitride Membranes

Membranes are typically created by a thin silicon nitride (SIN) layer deposited on a silicon wafer. Both, top and bottom side of the wafer is covered by a thin layer of the silicon nitride. The ...

Matějka, Milan; Krátký, Stanislav; Řiháček, Tomáš; Kolařík, Vladimír; Chlumská, Jana; Urbánek, Michal
Ústav přístrojové techniky, 2017

Non-holonomic planar and spatial model of a ball-type tuned mass damping device
Náprstek, Jiří; Fischer, Cyril
2017 - English
The area of tuned mass dampers is a wide field of inspiration for theoretical studies in non-linear dynamics and dynamic stability. The studies attempt to estimate behaviour of diverse damping devices and their reliability. The current paper deals with the response of a heavy ball rolling inside a spherical cavity under horizontal kinematic excitation. The non-linear system consists of six degrees of freedom with three non-holonomic constraints. The contact between the ball and the cavity surface is supposed to be perfect without any sliding. The mathematical model using the Appell-Gibbs function of acceleration energy is developed and discussed. Comparison with previous planar (SDOF) model which is based on the Lagrangian procedure is given. The system has an auto-parametric character and therefore semi-trivial solutions and their dynamic stability can be analysed. The most important post-critical regimes are outlined and qualitatively evaluated in resonance domain. Numerical experiments were performed when excitation frequency is slowly swept up and down to identify different modes of response. Some applications in civil engineering as a tuned mass damper, which can be used on slender structures, are mentioned. The proposed device is compared with a conventional pendulum damper. Strengths and weaknesses of both absorbers types\nare discussed. Keywords: tuned mass damper; moving ball; Appell-Gibbs formulation Available at various institutes of the ASCR
Non-holonomic planar and spatial model of a ball-type tuned mass damping device

The area of tuned mass dampers is a wide field of inspiration for theoretical studies in non-linear dynamics and dynamic stability. The studies attempt to estimate behaviour of diverse damping devices ...

Náprstek, Jiří; Fischer, Cyril
Ústav teoretické a aplikované mechaniky, 2017

Návrh integrovaného emisního procesoru nové generace
Resler, Jaroslav; Juruš, Pavel; Benešová, N.; Vlček, O.; Belda, M.; Huszár, P.; Krč, Pavel; Eben, Kryštof
2017 - Czech
V podstatě jediným rozšířeným a veřejně dostupným nástrojem pro modelování emisí pro potřeby CTM je procesor SMOKE (Coats & Carlie, 1996). Problém modelu SMOKE ovšem je v jeho silné vazbě na podmínky USA. V minulosti došlo k několika pokusům uzpůsobit model SMOKE jiným podmínkám - viz např. práce reportované v Bieser et al., 2011 nebo Borge et al., 2008, úsilí ovšem vždy naráželo na limity designu tohoto emisního procesoru. Naším cílem je vyvinout emisní procesor založený na otevřených technologiích, který bude komfortní pro typické využití v CTM v našich podmínkách a který bude dostatečně flexibilní, aby byl snadno konfigurovatelný a nastavitelný i pro ostatní uživatele ve světě a jejich specifické potřeby. The only publicly available and widely used tool for emission modelling for CTM is the processor SMOKE (Coats & Carlie, 1996), but its usage is limited by its strong dependence on conditions of USA. A few attempts to adjust SMOKE to other conditions were made in the past - see e.g. works reported in Bieser et al., 2011 or Borge et al., 2008, but the efforts hit the limits of its design. Our goal is to develop an emission processor based on open technologies which will be easy to use for typical usage with CTM in our conditions and which will be flexible and configurable enough to serve specific needs of users in other countries over the world. Keywords: emission model; CTM; postgresql; postgis; inventory Available at various institutes of the ASCR
Návrh integrovaného emisního procesoru nové generace

V podstatě jediným rozšířeným a veřejně dostupným nástrojem pro modelování emisí pro potřeby CTM je procesor SMOKE (Coats & Carlie, 1996). Problém modelu SMOKE ovšem je v jeho silné vazbě na podmínky ...

Resler, Jaroslav; Juruš, Pavel; Benešová, N.; Vlček, O.; Belda, M.; Huszár, P.; Krč, Pavel; Eben, Kryštof
Ústav informatiky, 2017

Evaluation of the turbulent kinetic dissipation rate in an agitated vessel
Kysela, Bohuš; Konfršt, Jiří; Chára, Zdeněk; Sulc, R.; Jašíková, D.
2017 - English
The design of agitated tanks depends on operating conditions and processes for that are used for. An important parameter for the scale-up modelling is the dissipation rate of the turbulent kinetic energy. The dissipation rate is commonly assumed to be a function of the impeller power input. But this approach gives no information about distribution of the dissipation rate inside the agitated volume. In this paper the distributions of the dissipation rate inside the agitated vessels are estimated by evaluations of the CFD (Computational Fluid Dynamics). The results obtained from RANS (Reynolds Averaged Navier-Stokes equations) k-epsilon turbulent model and LES (Large Eddy Simulations) with Smagorinsky SGS (Sub Grid Scale) model are compared. The agitated vessels with standard geometry equipped with four baffles and stirred by either a standard Rushton turbine or a high shear impeller were investigated. The results are compared with mean dissipation rate estimated from the total impeller power input. Keywords: flow; large-eddy simulation Fulltext is available at external website.
Evaluation of the turbulent kinetic dissipation rate in an agitated vessel

The design of agitated tanks depends on operating conditions and processes for that are used for. An important parameter for the scale-up modelling is the dissipation rate of the turbulent kinetic ...

Kysela, Bohuš; Konfršt, Jiří; Chára, Zdeněk; Sulc, R.; Jašíková, D.
Ústav pro hydrodynamiku, 2017

Local velocity scaling in T400 vessel agitated by Rushton turbine in a fully turbulent region
Šulc, R.; Ditl, P.; Fořt, I.; Jašíková, D.; Kotek, M.; Kopecký, V.; Kysela, Bohuš
2017 - English
The hydrodynamics and flow field were measured in an agitated vessel using 2-D Time Resolved Particle Image Velocimetry (2-D TR PIV). The experiments were carried out in a fully baffled cylindrical flat bottom vessel 400 mm in inner diameter agitated by a Rushton turbine 133 mm in diameter. The velocity fields were measured in the zone in upward flow to the impeller for impeller rotation speeds from 300 rpm to 850 rpm and three liquids of different viscosities (i.e. (i) distilled water, ii) a 28% vol. aqueous solution of glycol, and iii) a 43% vol. aqueous solution of glycol), corresponding to the impeller Reynolds number in the range 50 000 < Re < 189 000. This Re range secures the fully-developed turbulent flow of agitated liquid. In accordance with the theory of mixing, the dimensionless mean and fluctuation velocities in the measured directions were found to be constant and independent of the impeller Reynolds number. On the basis of the test results the spatial distributions of dimensionless velocities were calculated. The axial turbulence intensity was found to be in the majority in the range from 0.388 to 0.540, which corresponds to the high level of turbulence intensity. Fulltext is available at external website.
Local velocity scaling in T400 vessel agitated by Rushton turbine in a fully turbulent region

The hydrodynamics and flow field were measured in an agitated vessel using 2-D Time Resolved Particle Image Velocimetry (2-D TR PIV). The experiments were carried out in a fully baffled cylindrical ...

Šulc, R.; Ditl, P.; Fořt, I.; Jašíková, D.; Kotek, M.; Kopecký, V.; Kysela, Bohuš
Ústav pro hydrodynamiku, 2017

Chemical and microstructural characterization of the render, sampled from Gloriette, the US Embassy in Prague 1
Slížková, Zuzana; Frankeová, Dita; Viani, Alberto; Hauková, Petra; Koudelková, Veronika; Svoboda, Milan
2017 - English
The aim of the work was to analyze the mortar taken from the Gloriette (US Embassy, Prague 1). Analyzes were performed for the binder and filler characterization and the sample was also dissolved in HCl to determine the mixing ratio. Keywords: survey; material characterization; chemical composition; binder and aggregate characterization Available at various institutes of the ASCR
Chemical and microstructural characterization of the render, sampled from Gloriette, the US Embassy in Prague 1

The aim of the work was to analyze the mortar taken from the Gloriette (US Embassy, Prague 1). Analyzes were performed for the binder and filler characterization and the sample was also dissolved in ...

Slížková, Zuzana; Frankeová, Dita; Viani, Alberto; Hauková, Petra; Koudelková, Veronika; Svoboda, Milan
Ústav teoretické a aplikované mechaniky, 2017

Keltské meče
Kumpová, Ivana
2017 - Czech
Práce byla zaměřena na vytvoření metodiky využívající rentgenové (RTG) tomografické zobrazování pro průzkumy historických artefaktů na bázi kovů. V laboratoři RTG tomografie byly touto metodou zkoumány dva objekty – byly provedeny dvě tomografie raně středověkého meče v prekonzervační fázi doplněné o testovací měření bronzového náramku ze stejného období. Průzkum byl proveden za účelem odhalení technologie výroby, výzdoby a případných poškození. The work was focused on the development of the methodology using X-ray tomographic imaging for exploration of metal-based historical artefacts. In the laboratory of X-ray tomography, two objects were examined by this method - two tomography measurements of the early medieval sword in the pre-conservative phase were taken, supplemented by imaging if the bronze bracelet of the same period. The survey was conducted to reveal the technology of production, decoration and possible damage. Keywords: X-ray tomography; medieval sword; historical artefacts Available at various institutes of the ASCR
Keltské meče

Práce byla zaměřena na vytvoření metodiky využívající rentgenové (RTG) tomografické zobrazování pro průzkumy historických artefaktů na bázi kovů. V laboratoři RTG tomografie byly touto metodou ...

Kumpová, Ivana
Ústav teoretické a aplikované mechaniky, 2017

An adaptive recursive multilevel approximate inverse preconditioning: Computation of the Schur complement
Kopal, Jiří; Rozložník, Miroslav; Tůma, Miroslav
2017 - English
Available in digital repository of the ASCR
An adaptive recursive multilevel approximate inverse preconditioning: Computation of the Schur complement

Kopal, Jiří; Rozložník, Miroslav; Tůma, Miroslav
Ústav informatiky, 2017

Impact of Turbulence Generators on Turbulent Characteristics and Structures
Kellnerová, Radka; Jurčáková, Klára; Jaňour, Zbyněk
2017 - English
The turbulent generators are routinely used to produce very turbulent flows. Special type of vertically slenderize spires are applied to enhance turbulent diffusion from the surface upwards in order to increase the boundary layer depth. This paper studies the influence of variable upstream distance of generators on formation of both vortical and non-vortical organized structures within a test section. The 2-component 2-dimensional time-resolved particle image velocimetry measurement of the flow was performed in the wind channel with very rough surface. Intermittent flow dynamics was evaluated by means of higher order moments, vorticity, quadrant and wavelet analysis. The downstream evolution of the flow suggests that equilibrium between roughness- and spires-produced turbulence was reached at the distance of 7 spires height.\n Keywords: turbulence generator; wind channel; vorticity; quadrant analysis Fulltext is available at external website.
Impact of Turbulence Generators on Turbulent Characteristics and Structures

The turbulent generators are routinely used to produce very turbulent flows. Special type of vertically slenderize spires are applied to enhance turbulent diffusion from the surface upwards in order ...

Kellnerová, Radka; Jurčáková, Klára; Jaňour, Zbyněk
Ústav termomechaniky, 2017

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