Number of found documents: 14440
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Application of non-contact vibration measurements on a 48“ blade under low load condition
Kubín, Z.; Liška, J.; Míšek, T.; Procházka, Pavel
2017 - English
The paper describes in detail a Tip-Timing measurement on a combined cycle power plant with a steam turbine power output of 270MW. Newly developed magnetoresistive and optical sensors were used as well as standard eddy-current sensors to measure blade vibration under low load condition and variable back pressure. New hardware solution for the Tip-Timing measurement will is presented as well as results of measurements of relative amplitudes and excited nodal diameters. Keywords: steam turbine; non-contact vibration measurement; magnetoresistive sensor; optical sensor Available at various institutes of the ASCR
Application of non-contact vibration measurements on a 48“ blade under low load condition

The paper describes in detail a Tip-Timing measurement on a combined cycle power plant with a steam turbine power output of 270MW. Newly developed magnetoresistive and optical sensors were used as ...

Kubín, Z.; Liška, J.; Míšek, T.; Procházka, Pavel
Ústav termomechaniky, 2017

Proposal of hyperelastic proportional damping as dissipated energy model of hard rubbers
Šulc, Petr; Pešek, Luděk; Bula, Vítězslav; Košina, Jan; Cibulka, Jan
2017 - English
The paper deals with a stress analysis of hard rubber under large torsion deformations. This study was motivated by effort to find the dependency the dissipated energy on the deformation energy. Based on the results of an experiment, a function of dissipation energy of hard rubbers for finite strains using the theory hyperelasticity was proposed herein analogically as a proportional damping for elastic theory. Samples of hard rubber of different hardness (EPDM, Silicone) were dynamically tested on the developed torsional test-rig at different frequencies, amplitudes. First the Mooney Rivlin model (MRM) for a shear case of loading was analytically developed and then MRM constants were attained by fitting of the MRM to the experimental torsion-deformation curve. These constants were used to obtain the deformation energy of the MRM models. The coefficients of hyperelastic proportional damping relating a dissipated energy to a strain energy were evaluated for tested rubbers on the basis of experimental results. Keywords: torsion vibration; large deformation; hyperelasticity; dissipated energy; deformation energy Available at various institutes of the ASCR
Proposal of hyperelastic proportional damping as dissipated energy model of hard rubbers

The paper deals with a stress analysis of hard rubber under large torsion deformations. This study was motivated by effort to find the dependency the dissipated energy on the deformation energy. Based ...

Šulc, Petr; Pešek, Luděk; Bula, Vítězslav; Košina, Jan; Cibulka, Jan
Ústav termomechaniky, 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

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

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

Influence of hydrodynamic nozzle wear on erosion effect of self-excited pulsating water jet
Klich, Jiří; Říha, Zdeněk; Foldyna, Vladimír
2017 - English
The article deals with the study of the wear of the hydrodynamic nozzle and its\ninfluence on the generation of a self-excited pulsating water jet (SPWJ). The nozzle\nwas monitored for the ability of the waterjet to erode the surface of the aluminum\nalloy EN AW 6060 at regular intervals. Keywords: hydrodynamic nozzle; waterjet; erosion Available in a digital repository NRGL
Influence of hydrodynamic nozzle wear on erosion effect of self-excited pulsating water jet

The article deals with the study of the wear of the hydrodynamic nozzle and its\ninfluence on the generation of a self-excited pulsating water jet (SPWJ). The nozzle\nwas monitored for the ability of ...

Klich, Jiří; Říha, Zdeněk; Foldyna, Vladimír
Ústav geoniky, 2017

Properties and characteristics of recycled garnet abrasives for AWJ
Martinec, Petr; Hlaváček, Petr; Ruppenthalová, Lucie; Sitek, Libor
2017 - English
The use of recycled garnet abrasive from sludge after cutting materials is a current\nproblem. The behavior of individual garnet abrasives in the AWJ process depends\non the geological origin of the garnets, which also affects all the material\ncharacteristics of the garnet recyclate. The parameters of the BARTON HPX80 and\nGMA 80 abrasive inputs and their recycled products were compared: mineralogical\ntype, apparent density, granularity, grain shape and mineralogical purity,\nmicrohardness data and the degree of damage to the garnet grains. All individual\nparameters of abrasives and their recyclates are reflected in the index of cutting\nefficiency of abrasive. The effect of abrasive material properties on cuttability of\nabrasives is synergistic. The new parameters in the evaluation of abrasives are\nmicro-hardness (brittleness criterion), specific surface and pore size distribution\n(internal grain damage criterion). Keywords: garnet; abrasive water jet; recycled abrasives; index of cutting efficiency of abrasive; microhardnes Available in a digital repository NRGL
Properties and characteristics of recycled garnet abrasives for AWJ

The use of recycled garnet abrasive from sludge after cutting materials is a current\nproblem. The behavior of individual garnet abrasives in the AWJ process depends\non the geological origin of the ...

Martinec, Petr; Hlaváček, Petr; Ruppenthalová, Lucie; Sitek, Libor
Ústav geoniky, 2017

Application of Electric Probes for Study of Structure of Thermal Plasma Jet.
Hurba, Oleksiy; Hrabovský, Milan
2017 - English
Thermal plasma at atmospheric pressure was investigated. Electric probes and doable probe used as relatively simple and efficient tool for diagnostic of structure of flow field in thermal plasma jet. Were defined plasma potential and boundaries of the conducting region and their changing for the diferent operating modes of plasma torch. Keywords: Electric probes; double probe; thermal; plasma jet Available at various institutes of the ASCR
Application of Electric Probes for Study of Structure of Thermal Plasma Jet.

Thermal plasma at atmospheric pressure was investigated. Electric probes and doable probe used as relatively simple and efficient tool for diagnostic of structure of flow field in thermal plasma jet. ...

Hurba, Oleksiy; Hrabovský, Milan
Ústav fyziky plazmatu, 2017

SMV-2017-03: Planární mikrostruktury pro optické aplikace
Horáček, Miroslav; Kolařík, Vladimír; Matějka, Milan; Krátký, Stanislav; Chlumská, Jana; Meluzín, Petr; Král, Stanislav
2017 - Czech
Vývoj planárních mikrostruktur pro optické aplikace a následná realizace vzorků metodou elektronové litografie. Projekt zahrnuje zpracování a analýzu technického zadání, návrh optimální planární mikrostruktury realizující požadované optické vlastnosti, výzkum a modelování možností fyzikální a technologické realizace mikrostruktur s ohledem na limity vědeckých přístrojů, kterými disponujeme ve své laboratoři, přípravu datových vstupů pro expozici na elektronovém litografu, vlastní realizaci vzorků, vyhodnocení těchto vzorků a zpracování technické dokumentace. Development in the field of planar microstructures for optical applications, physical realization of structures by means of electron beam lithography. The project covers the processing and analysis of the graphical motive, research and application of planar microstructures performing required optical properties, research and modeling of the physical possibilities of implementation of microstructures, regard to the limits of current scientific instruments in our laboratory, data preparation for e-beam lithography exposure, samples exposure, verification of properties of samples and technical documentation preparation. Keywords: planar; microstructures; optics; e-beam lithography Available at various institutes of the ASCR
SMV-2017-03: Planární mikrostruktury pro optické aplikace

Vývoj planárních mikrostruktur pro optické aplikace a následná realizace vzorků metodou elektronové litografie. Projekt zahrnuje zpracování a analýzu technického zadání, návrh optimální planární ...

Horáček, Miroslav; Kolařík, Vladimír; Matějka, Milan; Krátký, Stanislav; Chlumská, Jana; Meluzín, Petr; Král, Stanislav
Ústav přístrojové techniky, 2017

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