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Experimentální výzkum spolehlivosti těsnění kabelových prostupů v Pražském metru po povodních v létě 2002
Jíra, J. ; Jírová, Jitka ; Bouška, P. ; Vokáč, M.
Confluence of the rivers Berounka and Sázava and outflows from the Vltava dam cascade caused the flow in the lower part of the river Vltava in Prague. The Vltava culminated in Prague on 14 August with a flow of 5160 m3.s-1; this corresponds to a period of recurrence of 500 years. The extension of floods in the Vltava valley in Prague caused penetration of water into underground spaces of the Metro and water flooded 19 of 53 underground stations. Looseness of cable bushings through pressure interfaces and non-closure of some pressure interfaces were the most important cause of spreading of water in underground spaces. After the floods of August 2002 the accredited laboratory CTU in Prague, Klokner Institute designed a methodology of experiments and testing system and performed tests on reliability of cable bushings and on material properties of the U 5000. Results of experiments lead to the recommendation to replace all the existing cable bushing in Prague Metro
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Vztah mezi materiálovými vlastnosti spongiózní kosti a její relativní hustotou stanovený pomocí malých vzorků a optické metody
Jiroušek, Ondřej
Experimental procedures utilizing an optical identification method used for evaluation of mechanical properties of cancellous bone using small samples of cylindrical shape are described in the paper. To measure very small strains of the cancellous bone, high-resolution CCD-camera and algorithm making use of sub-pixel determination of the centre-of-gravity of the markers are used. The experimental procedures serve for consequent evaluation of the relationship between apparent density and Young\'s modulus of elasticity and ultimate strength of the cancellous bone
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