Problems in Different Measuring and Assessment the Modulus of Deformation Using the Czech and German Methodologies

Comparative laboratory and in-situ measurements were used to establish the relationships between the static moduli of deformation calculated under the ED methodology and the DB methodology. The measurements proved that the moduli of deformation determined in accordance with the two methodologies cannot be substituted for each other.

Prerequisites for Increasing the Axle Load on Railway Tracks in the Czech Republic

This paper deals with problems of increasing the axle load on Czech Railways (ED) tracks to 250 kN or 300 kN, respectively. The results of a numerical analysis of the effects of increased axle loads on the track bed structure were verified by experimental measurements carried out on track bed construction models in an experimental box on a 1:1 scale. The results of the research are applicable for routine use on ED.

Badanie stabilizatora na bazie popiołu lotnego w podbudowie torów kolejowym oraz określenie modułu Younga

This paper deals with the investigation of the fly ash-based stabilizer used as a layer in railway track bed. It is a “new” material in railway structures. The main purpose of stabilizer is to reinforce railway track bed. The above mentioned fly ash-based stabilizer is a mixture consists of fly ash from Chvaletice plant in the Czech Republic, FGD gypsum, calcium oxide and water. The laboratory tests of the fly ash-based stabilizer have started in 2000 in order to define the key physical properties and also material suitability in the field of railway substructure. For the purpose of the 1:1 scale material verification, a box device with dimensions of 990 × 800 × 2095 mm for full scale testing was designed. On the base of the laboratory tests the 330 m long trial section of railway track was stabilized at the Smiřice railway station. The test layer under track No. 3 was built in April 2005 and the extraction of the material for laboratory test is done on regular basis - each spring and autumn. The paper is focused on sampling of the fly ash-based stabilizer by core drilling for following laboratory tests. The experience with in situ sampling in railway track bed led to recommendation summarized in the conclusion. The layer of stabilizer, which is placed under railway ballast and crushed stone, was uncovered and the boreholes with diameter 100 mm were done. According to the difficulty of sampling it was possible to extract only a small amount of specimens for the determination of the performance and durability of the fly ash-based stabilizer. It was necessary to exclude some of sampled specimens which with high probability include predisposed surface failures that might significantly affect the average value of the young's modulus. The goal was to choose three specimens for the pressure test. Ultrasonic method and also Impulse Excitation Method were chosen as non destructive test methods for the determination of dynamic modulus of elasticity, which could denote the suitable samples for the pressure test. At the end of the paper the results of determined young's modulus and dynamic modulus of elasticity are also described. The most important findings in the comparison of non-destructive and destructive tests are discussed. These results can significantly support the knowledge of the stabilizer in the long-term monitoring of the trial section in Smiřice.Niniejsza praca dotyczy badań stabilizatora na bazie popiołu lotnego użytego jako warstwa podtorza kolejowego. Jest to “nowy materiał” stosowany w budowie szyn. Głównym celem stabilizatora jest wzmocnienie podtorza kolejowego. Wspomniany stabilizator na bazie popiołu lotnego jest mieszanką składającą się z popiołu lotnego powstałego ze spalania rośliny Chvaletice, rosnącej w Republice Czeskiej, gipsu z odsiarczania spalin, tlenku wapnia oraz wody. Testy laboratoryjne stabilizatora na bazie popiołu lotnego rozpoczęto w 2000 r. w celu określenia kluczowych właściwości fizycznych oraz wyboru najodpowiedniejszego materiału stosowanego do budowy trakcji. W celu sprawdzenia materiału w skali 1:1, stworzono specjalne urządzenie w kształcie skrzyni o wymiarach 990×800×2095 mm, co umożliwiło przeprowadzenie testówpełnowymiarowych. Na bazie testów laboratoryjnych przeprowadzono stabilizację próbnego odcinka trakcji szynowej o długości 330 m na stacji kolejowej w miejscowości Smiřice. Warstwa próbna została położona przy trakcji nr 3 w kwietniu 2005 r. Próbki materiału są regularnie pobierane do testów laboratoryjnych każdej wiosny i jesieni. W pracy skupiono się na próbkach stabilizatora na bazie popiołu lotnego wywierconych z rdzenia na potrzeby testów laboratoryjnych. Rekomendacje przedstawione we wniosku zostały oparte na doświadczeniach przeprowadzonych na próbkach pobranych z wyżej wymienionego podtorza.Warstwa stabilizatora, położona pod nawierzchnią torową oraz skruszonym kamieniem, została odkryta, a następnie wywiercono otwory o średnicy 100 mm. Z powodu utrudnień związanych z poborem próbek, udało się uzyskać tylko niewielką ich ilość potrzebną do określenia skuteczności i wytrzymałości stabilizatora na bazie popiołu lotnego. Z badań należało wyłączyć niektóre próbki, które z dużym prawdopodobieństwem miały predyspozycje do wad powierzchniowych, przez co mogły znacznie wpłynąć na średnią wartość modułu Younga. Celem był wybór trzech próbek do przeprowadzenia prób ciśnieniowych. Do testów wybrano metody ultradźwiękową oraz wzbudzenia impulsu, które są nieinwazyjnymi metodami badawczymi, dzięki którym sprawdza się dynamiczny moduł sprężystości, co pomaga w doborze odpowiednich próbek potrzebnych do przeprowadzenia prób ciśnieniowych. Na końcu pracy badawczej opisano wyniki oznaczenia modułu Younga oraz modułu sprężystości. Omówiono najważniejsze wnioski, które uzyskano na podstawie porównania testów inwazyjnych oraz nieinwazyjnych. Wyniki niniejszych badań znacząco wzbogacają wiedzę na temat zmian właściwości stabilizatora stwierdzone w wyniki długoterminowych obserwacji odcinka próbnego w Smiřice

Problems in Different Measuring and Assessment the Modulus of Deformation Using the Czech and German Methodologies

Comparative laboratory and in-situ measurements were used to establish the relationships between the static moduli of deformation calculated under the ED methodology and the DB methodology. The measurements proved that the moduli of deformation determined in accordance with the two methodologies cannot be substituted for each other.

Experimentalni a matematicka analyza vicevrstveho systemu zeleznicni trati.

Available from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi

Direct Probing of Dispersion Quality of ZrO2 Nanoparticles Coated by Polyelectrolyte at Different Concentrated Suspensions

This study reports useful application of the electrokinetic sonic amplitude (ESA) technique in combination with rheometry and electron microscopy techniques for direct probing the stability of low and high-concentrated zirconia (ZrO(2)) nanosuspensions in the presence of an alkali-free anionic polyelectrolyte dispersant Dolapix CE64. A comparative study of the electrokinetic characteristics and the rheological behavior of concentrated ZrO(2) nanosuspensions has been done. Good agreement was obtained from relationship between the electrokinetic characteristics (zeta potential, ESA signal), viscosity, and its pH dependence for each concentrated ZrO(2) nanosuspension with different dispersant concentration in the range of 0.9–1.5 mass%. A nanoscale colloidal hypothesis is proposed to illustrate that the addition of different amounts of dispersant influences on both the stability and the electrokinetic and rheological properties of concentrated ZrO(2) nanosuspensions. It is found that an optimum amount of 1.4 mass% dispersant at the inherent pH (>9.2) can be attached fully onto the nanoparticles with sufficient electrosteric dispersion effects, suitable for casting applications. Supplementary scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM) analyses followed by colorization effect were taken to verify the visible interaction between dispersant and nanoparticles surfaces. SEM and HR-TEM images proved the existence of visible coverage of dispersant on the surface of individual nanoparticles and showed that thin polyelectrolyte layers were physically bound onto the particles’ surfaces. This study will be of interest to materials scientists and engineers who are dealing with dispersion technology, nanoparticle surface treatments, functionalization, characterization, and application of bio/nanoparticle suspensions at various concentrations using different types of polymers

Piezoelectric, dielectric and pyroelectric properties of 0-3 ceramic-polymer composites

The circular samples of composites were made from PZT ceramic grains dispersed in polymers (epoxy or rubber). Pressure dependencies of the hydrostatic piezoelectric coefficient dh and permittivity ε were measured in the range up to 60 MPa. The hydrostatic strain coefficient dh, the hydrostatic voltage coefficient gh and figure of merit dh·gh were determined using the static method. The pressure dependence of the hydrostatic coefficients was measured for several successive cycles. Experimental dependence of the charge on pressure and temperature was fitted by multi parameter function. The pressure and temperature dependencies of the hydrostatic dh and pyroelectric p3 coefficients were determined. It was found that the hydrostatic strain coefficient dh and hydrostatic voltage coefficient gh decreased and pyroelectric coefficient p3 increased with pressure at constant temperature.DFG [1102]; ICTP programme for Training and Research in Italian Laboratories (TRIL); German Bundesministerium fur Bildung und Forschung; Czech Republic MEYS Grants [ME492, LA242]; SAIL (CSR), Govt. of India; CERN-RFBR Grants [08-02-91009, 12-02-91500]; Portuguese FCT - Fundacao para a Ciencia e Tecnologia [CERN/FP/109323/2009, CERN/FP/116376/2010, CERN/FP/123600/2011]; MEXT; JSPS [18002006, 20540299, 18540281]; Daiko Foundation; Yamada Foundation; DFG cluster of excellence 'Origin and Structure of the Universe'; EU FP7 (HadronPhysics3) [283286]; Israel Science Foundation; Polish NCN Grant [DEC-2011/01/M/ST2/02350

Spin alignment and violation of the OZI rule in exclusive omega and phi production in pp collisions

Exclusive production of the isoscalar vector mesons omega and phi is measured with a 190 GeV/c proton beam impinging on a liquid hydrogen target. Cross section ratios are determined in three intervals of the Feynman variable x(F) of the fast proton. A significant violation of the OZI rule is found, confirming earlier findings. Its kinematic dependence on xF and on the invariant mass M-pV of the system formed by fast proton p(fast) and vector meson V is discussed in terms of diffractive production of p(fast) V resonances in competition with central production. The measurement of the spin density matrix element rho(00) of the vector mesons in different selected reference frames provides another handle to distinguish the contributions of these two major reaction types. Again, dependences of the alignment on x(F) and on M-pV are found. Most of the observations can be traced back to the existence of several excited baryon states contributing to omega production which are absent in the case of the phi meson. Removing the low-mass M-pV resonant region, the OZI rule is found to be violated by a factor of eight, independently of x(F). (C) 2014 CERN for the benefit of the COMPASS Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/3.0/).DFG [1102]; ICTP programme for Training and Research in Italian Laboratories (TRIL); German Bundesministerium fur Bildung und Forschung; Czech Republic MEYS Grants [ME492, LA242]; SAIL (CSR), Govt. of India; CERN-RFBR Grants [08-02-91009, 12-02-91500]; Portuguese FCT - Fundacao para a Ciencia e Tecnologia [CERN/FP/109323/2009, CERN/FP/116376/2010, CERN/FP/123600/2011]; MEXT; JSPS [18002006, 20540299, 18540281]; Daiko Foundation; Yamada Foundation; DFG cluster of excellence 'Origin and Structure of the Universe'; EU FP7 (HadronPhysics3) [283286]; Israel Science Foundation; Polish NCN Grant [DEC-2011/01/M/ST2/02350