Number of found documents: 8033
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Acta Polytechnica CTU Proceedings 7
Kytýř, Daniel; Zlámal, Petr
2017 - English
The International Symposium on Experimental Methods and Numerical Simulation in Engineering Sciences continues the tradition of the Czech-German bilateral symposium founded by prof. Karl-Hans Laermann and prof. Stanislav Holý in 1985. In the following years, the symposium was extensively developed by prof. Josef Jíra. The symposium shall bring together mainly young scientists who are actively involved in experimental solid mechanics, theoretically and practically, in order to exchange experience, to report on the present state-of-art as well as on running research projects, to discuss due questions and problems and to promote the co-operation between individuals as well as between institutions. Therefore in the symposium discussions will play a highly significant role. Keywords: experimental solid mechanics; numerical simulation Available at various institutes of the ASCR
Acta Polytechnica CTU Proceedings 7

The International Symposium on Experimental Methods and Numerical Simulation in Engineering Sciences continues the tradition of the Czech-German bilateral symposium founded by prof. Karl-Hans Laermann ...

Kytýř, Daniel; Zlámal, Petr
Ústav teoretické a aplikované mechaniky, 2017

Deformation behaviour of gellan gum based artificial bone structures under simulated physiological conditions
Krčmářová, N.; Šleichrt, J.; Fíla, Tomáš; Koudelka_ml., Petr; Kytýř, Daniel
2017 - English
The paper deals with investigation of deformation behaviour of gellan gum (GG) based\nstructures prepared for regenerative medicine purposes. Investigated material was synthesized as porous spongy-like scaffold reinforced by bioactive glass (BAG) nano-particles in different concentrations. Deformation behavior was obtained employing custom designed experimental setup. This device equipped with bioreactor chamber allows to test the delivered samples under simulated physiological conditions with controlled flow and temperature. Cylindrical samples were subjected to uniaxial quasi-static loading in tension and compression. Material properties of plain scaffold buffered by 50 wt% and 70 wt% BAG were derived from a set of tensile and compression tests. The results are represented in form of stress-strain curves calculated from the acquired force and displacement data. Keywords: gellan gum scaffold; reinforcement; uni-axial loading; simulated physiological conditions Available at various institutes of the ASCR
Deformation behaviour of gellan gum based artificial bone structures under simulated physiological conditions

The paper deals with investigation of deformation behaviour of gellan gum (GG) based\nstructures prepared for regenerative medicine purposes. Investigated material was synthesized as porous ...

Krčmářová, N.; Šleichrt, J.; Fíla, Tomáš; Koudelka_ml., Petr; Kytýř, Daniel
Ústav teoretické a aplikované mechaniky, 2017

Appearance Acquisition and Analysis of Effect Coatings
Filip, Jiří; Maile, F. J.
2017 - English
Keywords: effect coatings; appearance capturing; polychromatic; particle orientation Fulltext is available at external website.
Appearance Acquisition and Analysis of Effect Coatings

Filip, Jiří; Maile, F. J.
Ústav teorie informace a automatizace, 2017

On Finite Element Approximation of Flow Induced Vibration of Elastic Structure
Valášek, J.; Sváček, P.; Horáček, Jaromír
2017 - English
In this paper the fluid-structure interaction problem is studied on a simplified model of the human vocal fold. The problem is mathematically described and the arbitrary Lagrangian-Eulerian method is applied in order to treat the time dependent computational domain. The viscous incompressible fluid flow and linear elasticity models are considered. The fluid flow and the motion of elastic body is approximated with the aid of fininite element method. An attention is paid to the applied stabilization technique. The whole algorithm is implemented in an in-house developed solver. Numerical results are presented and the influence of different inlet boundary conditions is discused. Keywords: stabilized finite element method; 2D Navier-Stokes equations; vocal folds; aeroelasticity Available at various institutes of the ASCR
On Finite Element Approximation of Flow Induced Vibration of Elastic Structure

In this paper the fluid-structure interaction problem is studied on a simplified model of the human vocal fold. The problem is mathematically described and the arbitrary Lagrangian-Eulerian method is ...

Valášek, J.; Sváček, P.; Horáček, Jaromír
Ústav termomechaniky, 2017

Characterization of Mo-B-C nanostructured coating microstructure by means of AEM and GDOES
Buršík, Jiří; Svoboda, Milan; Švábenská, Eva; Buršíková, V.; Souček, P.; Zábranský, L.; Vašina, P.
2017 - English
A Mo-B-C nanostructured coating was prepared on WC-Co hard-metal substrate by magnetron sputtering. The details of microstructure of deposited thin layer as well as elements redistribution caused by subsequent annealing at 1000°C were studied by several experimental techniquec. Keywords: coating; nanostructure; analytical electron microscopy Available at various institutes of the ASCR
Characterization of Mo-B-C nanostructured coating microstructure by means of AEM and GDOES

A Mo-B-C nanostructured coating was prepared on WC-Co hard-metal substrate by magnetron sputtering. The details of microstructure of deposited thin layer as well as elements redistribution caused by ...

Buršík, Jiří; Svoboda, Milan; Švábenská, Eva; Buršíková, V.; Souček, P.; Zábranský, L.; Vašina, P.
Ústav fyziky materiálů, 2017

Mechanical properties of Cr-DLC layers prepared by hybrid laser technology
Písařík, Petr; Jelínek, Miroslav; Remsa, J.; Tolde, Z.
2017 - English
Diamond like carbon (DLC) layers have excellent biological properties for use in medicine for coating implants, but poor adhesion to biomedical alloys (titanium alloys, chromium alloys and stainless steel). The adhesion can be improved by doping the DLC layer by chromium, as described in this article. Chromium doped diamond like carbon layers (Cr DLC) were deposited by hybrid deposition system using KrF excimer laser (deposition diamond like carbon - graphite target) and\nmagnetron sputtering (deposition chromium - chromium target). Carbon and chromium contents were determined by wavelength dispersive X-ray spectroscopy.\n Keywords: DLC; chromium doped; mechanical properties; PLD Available at various institutes of the ASCR
Mechanical properties of Cr-DLC layers prepared by hybrid laser technology

Diamond like carbon (DLC) layers have excellent biological properties for use in medicine for coating implants, but poor adhesion to biomedical alloys (titanium alloys, chromium alloys and stainless ...

Písařík, Petr; Jelínek, Miroslav; Remsa, J.; Tolde, Z.
Fyzikální 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

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

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

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