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Design, development and realization of vibration measurement on riding metro wheel with and without add-on damper
Pešek, Luděk ; Vaněk, František ; Vaněk, Petr ; Cibulka, Jan
The aim of this research was design, developement and realization of vibration measurement (acceleration) of the riding metro wheel with and without add-on damper. The radiotelemetric method with four measurement channels was used for the operational measurement of vibration and noise. The solution was devided into four steps a) design and devolopement, laboratory tests and production of modified radiotelemtric equipment for measurement on the tram wheel; b) installation of the sensors and radiotelemetric equipment; c) realization of vibration operational measurement; d) measured data processing. In the report there is described a methodology of measurement and dynamic analysis used for comparision of the wheel with and withoud add-on dampers. The different riding regimes and tracks, i.e. direct, bow , were analysed. The third octave spectra nd amplitude time-frequency characteristics of accelerations and acoustic pressure were evaluated from the digital recorded time signals.
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The influence of the water quality on managed ichthyocenosis in the Berounka River, 1975-2003
Pivnička, K. ; Humpl, Martin
In 1962-2004 the stepwise increase of the concentration of NO3-, NH4+, Cl-, and SO42- was found up to the end of 1980´s with their subsequent decrease; only for BOD the gradual decrease in all sites and years was observed. These environmental factors (EF) together with the fishery statistics from two fishing wards (B7 and B8) in the Berounka River near Radnice were used in RDA models for the evaluation of the variability in fish assemblage structure in relation to the given EF. The best results in both wards were obtained using model with three EF (BOD, NO3-, SO42-), next models with four (five) factors explained more variability, some EF were, however, not significant. The partial effect of carp as EF on the yield of other species was non significant in B7 and closely above the significance (p=0.036) in B8. The changes in the frequency of fish species in fishery statistics are influenced by EF; the fishery statistics can be used for the evaluation of changes in fish assemblages in the past.
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The solid depozited precipitation in the small catchments in the Czech Republic
Fišák, Jaroslav ; Tesař, Miroslav
The samples were collected in two localities differing in the industrial pollutant load. The first locality situated in the Sumava Mts. represents a relatively clean region of the Czech Republic. The second locality is situated in the Northern Bohemia. This locality is represented by the Milesovka Observatory of the IAP ASCR. The region is heavy polluted by the industrial load in this case. The one-shot sample collection in the Sumava Mts. at 28 localities was made on January 4th, 1990. There were shown: i) The ion concentrations in the rime water depend on the industrial load of the region and on the local pollutant sources; ii) The local pollutant sources play the main role in ion concentrations in rime water; iii) The ion concentrations decrease with altitude.
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Pollutant concentrtion in fog-water at Kopisty (1999 – 2004)
Fišák, Jaroslav ; Chaloupecký, Pavel ; Fottová, D.
In this contribution, results of our studies devoted to analyses of fog water samples collected at the meteorological observatory over the period of 1999 - 2004 are summarized. The study deals with the parameters: conductivity, acidity and following selected ions: NH4+, Na+, Ca2+, Mg2+, K+, F-, Cl-, NO3- and SO42-. Overall, the total concentration of selected ions was remarkably decreasing during the period 2000 - 2004. Specifically, we found out an increase in the cation fraction for NH4+ and Ca2+, and a decrease in the anion NO3- fraction in the mean annual sample.
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Distribution and diversity of fish fry in different habitats of the Slapy reservoir
Kratochvíl, M. ; Kubečka, Jan ; Matěna, Josef
The fish fry assemblages of the Slapy reservoir (Czech Republic) were studied in May and June 2002. The aim of this study was to estimate diversity and distribution of fish fry in three habitats – epipelagic (depth 0 – 4 m), bathypelagic (depth 10 – 16 m) and littoral areas. Percids were present both in epipelagic and bathypelagic areas, while cyprinids preferred living in upper layers of the water column. During the dusk, bathypelagic fish started migration towards surface layers, throughout the dawn they returned back to the deeper layers. The highest densities of fish fry were observed in epipelagic zone during nighttime. Perch was revealed as the dominant fry species in Slapy reservoir, pikeperch was also abundant in the open water. Both during day and night, perch was usually the most common species in all habitats, cyprinids were most abundant in the littoral zone in May, only.
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