Number of found documents: 14683
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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

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 are 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

Formování kapek v systému dvou nemísitelných kapalin
Kysela, Bohuš; Konfršt, Jiří; Chára, Zdeněk; Šulc, R.; Jašíková, D.
2017 - Czech
Velikost kapek při míchání dvou vzájemně nemísitelných kapalin závisí především na působení vnějších sil. Smyková napětí působící na částici v závislosti na fyzikálních parametrech (povrchové napětí, hustota, viskozita) ovlivňují konečnou distribuci velikostí tvořených kapek. V první fázi jsme se pokusili modelovat dvě reálné nemísitelné kapaliny voda-silikonový olej, které jsou dány svými vlastnostmi. A to na jednoduchém případě výtoku z kapiláry, kde jsme se snažili ověřit, zda a jak moc přesně lze modelovat chování tohoto systému s různými odchylkami fyzikálních parametrů. Dále jsme se snažili určit rovnovážné a mezní stavy v závislosti na zadaných fyzikálních vlastnostech. The CFD simulation of simple two phase system using VOF model was verified by the real measurements. The system of two immiscible liquids silicone oil and water was tested on simple task with droplet formation from immersed jet. The setup of physical properties in CFD simulations was corrected by the experimental results. Keywords: VOF; liquid; multiphase Available at various institutes of the ASCR
Formování kapek v systému dvou nemísitelných kapalin

Velikost kapek při míchání dvou vzájemně nemísitelných kapalin závisí především na působení vnějších sil. Smyková napětí působící na částici v závislosti na fyzikálních parametrech (povrchové napětí, ...

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

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

Simulace zbytkových optických vad objektivu Merz 124/1477
Rail, Zdeněk; Melich, Zbyněk; Šrajer, Bohdan
2017 - Czech
Tento objektiv byl na Ústavu fyziky plazmatu,v.v.i., Centru Toptec v Turnově restaurován. Během tohoto procesu jsme získali možnost objektiv na optické lavici přeměřit a vyčíslit jeho zbytkové optické vady. Objektiv byl vyroben kolem roku 1860-1870. This objective lens was renoved in the Institute of Plasma Physics, v.v.i. Center Toptec in Turnov. During the process we got a possibility to measure the objective lens on the optical bench and to evaluate its residual optical aberrations. The objective lens was manufactured in 1860-1870 years Keywords: Achromatic dublet; spherochromatic aberration; coma; dispersion curve of glass; B-F chromatic correction Available at various institutes of the ASCR
Simulace zbytkových optických vad objektivu Merz 124/1477

Tento objektiv byl na Ústavu fyziky plazmatu,v.v.i., Centru Toptec v Turnově restaurován. Během tohoto procesu jsme získali možnost objektiv na optické lavici přeměřit a vyčíslit jeho zbytkové optické ...

Rail, Zdeněk; Melich, Zbyněk; Šrajer, Bohdan
Ústav fyziky plazmatu, 2017

Optické parametry význačných refraktorů
Rail, Zdeněk; Jareš, Daniel; Pintr, Pavel; Vápenka, David
2017 - Czech
V tomto referátu publikujeme optické parametry několika historických dalekohledů, které jsme v literatuře a na webových stránkách získali. Data byla vložena do optického programu ZEMAX, v němž byly vyčísleny jejich zbytkové vady. In this paper we publish the optical parameters of several historic telescopes, which we have found in scientific literature or web pages. Data were inputed into the optical program ZEMAX, which evaluated their residual aberrations. Keywords: Achromatic objective lens; spherochromatic aberration; coma; residual chromatic aberration; Index of refraction; dispersion curve of glass Available at various institutes of the ASCR
Optické parametry význačných refraktorů

V tomto referátu publikujeme optické parametry několika historických dalekohledů, které jsme v literatuře a na webových stránkách získali. Data byla vložena do optického programu ZEMAX, v němž byly ...

Rail, Zdeněk; Jareš, Daniel; Pintr, Pavel; Vápenka, David
Ústav fyziky plazmatu, 2017

Analysis of truncated data with application to the operational risk estimation
Volf, Petr
2017 - English
Analysis of operational risk often faces problems arising from the structure of available data, namely of left truncation and occurrence of heavy-tailed loss values. We deal with model given by lognormal dostribution contaminated by the Pareto one and to use of the Cramér-von Mises, Anderson-Darling, and Kolmogorov-Smirnov minimum distance estimators. Analysis is based on MC studies. The main objective is to propose a method of statistical analysis and modeling for the distribution of sum of\nlosses over a given period, particularly of its right quantiles. Keywords: operational risk; statistical analysis; truncated data Fulltext is available at external website.
Analysis of truncated data with application to the operational risk estimation

Analysis of operational risk often faces problems arising from the structure of available data, namely of left truncation and occurrence of heavy-tailed loss values. We deal with model given by ...

Volf, Petr
Ústav teorie informace a automatizace, 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

Correlated microscopy of electronic and material properties of graphene grown on diamond thin films
Rezek, Bohuslav; Čermák, Jan; Varga, Marián; Tulic, S.; Skákalová, V.; Waitz, T.; Kromka, Alexander
2017 - English
In this work we compare growth of graphene on diamond thin films that enable large area processing. We use films with different crystal size and surface roughness to obtain deeper insight into formation and properties of GoD. The diamond films are coated by a nm thin sputtered Ni layer and heated to 900°C in a forming gas atmosphere (H2/Ar) to initiate catalytic thermal CVD process. The samples are cleaned from residual Ni after the growth process. We employ scanning electron microscopy, Raman micro-spectroscopy and Kelvin probe force microscopy to correlate material, structural, and electronic properties of graphene on diamond. We show how grain size and grain boundaries influence graphene growth and material and electronic properties. For instance we show that the grain boundaries (with non-diamond carbon phases) in diamond films have an important role. They influence the electronic properties and they are beneficial for forming graphene on diamond higher quality. Keywords: graphene; diamond; microscopy; micro-spectroscopy; electronic properties Available at various institutes of the ASCR
Correlated microscopy of electronic and material properties of graphene grown on diamond thin films

In this work we compare growth of graphene on diamond thin films that enable large area processing. We use films with different crystal size and surface roughness to obtain deeper insight into ...

Rezek, Bohuslav; Čermák, Jan; Varga, Marián; Tulic, S.; Skákalová, V.; Waitz, T.; Kromka, Alexander
Fyzikální ústav, 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

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