Ostrava, Czech Republic
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IEC 61000-4-15 (Functional and design specification of flickermeter) specifies normalized flicker response and manufacturers must fit in with performance testing. Experience has shown that flickermeter implementations from different manufacturers, that process rectangular modulation patterns in identical manners, may still deviate from each other when processing other non-uniform voltage fluctuations. The paper describes generation of reproducible voltage varying signals with envelope shape typical for sawmill, heat pump, granulator, then it describes the unit under test and comparison of results.


Janiszewski K.,Silesian University of Technology | Gajdzik B.,Silesian University of Technology | Gryc K.,Technicka Univerzita Ostrava | Socha L.,Technicka Univerzita Ostrava | Bogdal A.,Czestochowa University of Technology
Solid State Phenomena | Year: 2015

The research on the process of steel filtration from non-metallic inclusions is currently entering the last phase of industrial experiments. Their positive effects confirm the previous theoretical assumptions and laboratory tests. The application of steel filtration as a permanent technological operation in the process of steel casting will remarkably improve its metallurgic purity. An additional advantage will be diminishing the probability of covering the outlet nozzle of a tundish. This paper presents an outline of the experiment results mentioned above. Due to the size of the text in the article, the effects of the type of flow (turbulent or laminar) the effectiveness of the filtration process. © (2015) Trans Tech Publications, Switzerland.


Durability and aesthetical characteristics of wooden products exposed outdoor are influenced by various factors: – wood species, treatment of wood, severity of exposure, etc. In this study have been investigated effects of accelerated weathering (in Xenotest with alternation of UV-light irradiation and water spray) on colour changes of samples from selected wood species (Scots pine − Pinus sylvestris L., beech − Fagus sylvatica L., and Norway spruce − Picea abies Karst. L.) painted with 1, 2 or 3 layers of brown acrylic coating Superwax. The lowest colour stability, valued in the CIE-L*a*b* colour system, had surfaces of beech wood painted only with 1 layer of Superwax. On the other hand, the highest resistance against discoloration had the spruce wood painted with 3 layers of this coating. © 2015, Technical University in Zvolen. All rights reserved.


Moldrik P.,Slovak University of Technology in Bratislava | Minarik D.,Technicka Univerzita Ostrava | Chvalek R.,Slovak University of Technology in Bratislava | Vaculik J.,Slovak University of Technology in Bratislava | Hradilek Z.,Slovak University of Technology in Bratislava
Proceedings of the 13th International Scientific Conference Electric Power Engineering 2012, EPE 2012 | Year: 2012

This paper describes practical experience gained through practical operation of a metal hydride container, which contains an alloy of La-Ce-Ni and has been used for storage of hydrogen produced by low-temperature electrolysers with a proton exchange membrane operated in the fuel cells laboratory at VŠB - TU Ostrava. Electric power required for production of hydrogen by electrolysis is supplied from photovoltaic panels.


Podhorna B.,UJP Prague a.s. | Andrsova I.,UJP Prague a.s. | Dobrovska J.,Technicka univerzita Ostrava | Vodarek V.,Technicka univerzita Ostrava | Hrbacek K.,Prvni brnenska strojirna Velka Bites a.s
Materials Science Forum | Year: 2014

This article summarises results of structure stability investigation of cast Ni-base and Cobase alloys after prolonged high temperature exposure at 900-1100 °C. Cast Ni(Co)-Cr-W-C alloys are resistant to high-temperature corrosion, due to high chromium content. Their heat resistance is caused by presence of carbides, which are stable at very high temperatures. Carbides precipitate in shape of large plate-like particles or carbide eutectics at casting cell boundaries, thus forming carbide skeleton of the alloy. Carbide morphology and temperature stability depends on chemical composition of the alloy, e.g. carbide content, type and content of carbide-forming elements. Microstructure changes were evaluated by stereological analysis and X ray-spectral microanalysis. © (2014) Trans Tech Publications, Switzerland.


Vrtek M.,Technicka Univerzita Ostrava
Proceedings of the 11th International Scientific Conference Electric Power Engineering 2010, EPE 2010 | Year: 2010

The present paper deals with the evaluation of the effectiveness of basic types of heat pumps. The coefficient of performance (COP) is solved from various viewpoints. In the fist case there is the COP solved from the direct energy input. In the second case the direct energy input is resolved to exergy. Finally, the recalculation to primary energy was done. All of these methods are useful for evaluation but each of them has its specific application. There are performed comparisons of compressor electric-driven and combustion engine-driven heat pumps and absorption heat pumps.


Miroslav K.Y.N.C.L.,Technicka univerzita Ostrava
Carpathian Journal of Earth and Environmental Sciences | Year: 2014

Samples of water and sludge were analysed from two different water treatment plants which produce drinking water from surface sources taken in two territories with different geology. In one territory, polymetalic deposits of Cu, Pb, Zn are located (primary rocks - Kulm). The second territory is located in the flysch range with no presence of heavy metals. Concentration of heavy metals (Cu, Cr, Ni, Pb, Cd, As, Hg, B) in water was below detection limits. Analyses of the sludge produced during coagulation filtering treatment have proved presence of heavy metals in the sludge. Following metals in the sludge: As, Cd, Cr, Cu, Hg, Mo, Ni, Pb, Zn. Most heavy metals are of anthropogenic origin. It is only Zn and As which originate in the geology of the catchment area. The heavy metal concentrations were low, the exception being As which was 30.6 mg/kg in dry mass of sludge for the Podhradí water treatment plant. This value is three times higher than the limit permitted for the sludge. Regular monitoring of heavy metal concentration in the water treatment sludge will improve assessment of presence of the heavy metals in the treated water.


Cechakova V.,Technicka univerzita Ostrava | Rosmanit M.,Technicka univerzita Ostrava | Fojtik R.,Technicka univerzita Ostrava
Procedia Engineering | Year: 2012

One of the typical bridge structures has been numerically modeled using finite element programs Scia Engineer and ANSYS. Main results from the numerical model were compared to those obtained from experimental testing of the structure. These numerical models were calibrated using experimental data from the static and dynamic load tests performed. Finally, future research on such structures is outlined. © 2012 Published by Elsevier Ltd.


Galas O.,Technicka univerzita Ostrava | Korinek R.,Technicka univerzita Ostrava | Michnova L.,Technicka univerzita Ostrava | Martinik L.,Technicka univerzita Ostrava
Advanced Materials Research | Year: 2013

This contribution is concerned with the issue of defects in rock that is accompanied by the withdrawal of heat during cooling the Massif from different strata in the rock structure. The defects affect the heating performance of heat pump system earth - water. Also, they affect the surface structure of soil above the moving collectors. This area in proposals of earth-water heat pump systems is being marginalized into the background by the majority of planners in case that it is solved. Therefore, there are stated the following possible break-downs and their solutions with respect to emphasis on geological and hydrological project. © (2013) Trans Tech Publications, Switzerland.


Vrtek M.,Technicka Univerzita Ostrava
Proceedings of the 13th International Scientific Conference Electric Power Engineering 2012, EPE 2012 | Year: 2012

This paper describes method that allows comparing different types of power plants with various nominal powers with using of combined energy-economic indicators. The article lists several examples of comparisons, both between different types of power plants and power plants of the same type differing only in the annual installed output utilisation.

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