1,284 research outputs found

    Empirical description of the hadron-hadron and hadron-nucleus interaction at the accelerator energy range

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    Taking into account several assumptions, a formula is transformed into two expressions for kaon and baryon plus antibaryon production in proton interaction and for pion production in pion interactions. Combining both formulae, expression are obtained for the spectrum of kaons and baryons plus antibaryons produced in the meson interactions. For analysis of the cosmic ray propagation in the atmosphere in actual fact, instead of the formulae for interactions of protons and mesons with protons, formulae appropriate for interactions with air nuclei was used. Using the method outlined among others by Elias et al. (1980) simple corrections were introduced to the derived expressions to account for the fact that the target is an air nucleus

    Potential for non-road modes to support environmentally friendly urban logistics

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    Road freight transport typically dominates in urban delivery operations. However, an increasing number of trials and commercial operations have started in the past 10 years attempting to use non-road modes in a wide range of cities including: Paris, Berlin, Madrid, Amsterdam and others. The research establishes the existing scale of rail freight in two comparable cities (London and Paris/Ile de France) and compares the development process in terms of the stakeholders, the infrastructure and planning issues and the nature of the operations. The review considers the scope and opportunity for an increase in the use of rail for urban freight transport and assesses the barriers to its wider implementation. The research is based on a mixture of desk research examining a number of cities and their use of rail freight transport combined with some interviews with the major stakeholders. The research contains an assessment of a number of pilot projects and initiatives that can be considered together and offer important insights into the potential for changes to urban distribution operations. The findings illustrate that rail plays a more important part than is often thought but that its uptake is restricted by the complex barriers to wider implementation. Planning limits and the complexity of engaging with the range of stakeholders has made it difficult to implement rail solutions for urban freight. It is clear that some of the developments can be considered as filling a rather narrow niche function. However, it is also apparent that some initiatives have the scope for wider implementation and to contribute significantly to reducing the reliance on road freight transport in cities. The analysis will support the work of urban planners and policy makers concerned with how to reach the EU target of essentially zero CO2 urban freight by 2030. In addition, the research identifies a number of barriers that need to be overcome and proposes ways to achieve this

    Influence of surface roughness on selected properties of the TiAlN coating

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    The HS6-5-2C steel samples with different surface roughness were used for the tests. After grinding had a roughness parameter of Ra = 0,03 μm, and after polishing Ra = 0,01 μm. A TiAlN coating was applied to the substrate prepared in this way. Using a confocal microscope with an interferometric mode, the geometrical structure of the samples was analyzed. The optical strain gauge was used to measure the contact angle. Tribological tests were carried out in conditions of technically dry friction. The polished sample with the coating was characterized by a more stable course of the friction coefficient, lower wear and a smaller wetting angle

    The influence of environmental conditions on the tribological properties of the Ti13Nb13Zr alloy

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    The paper presents the results of tribological tests of the Ti13Nb13Zr titanium alloy - carried out in the conditions of lubrication with liquids simulating body fluids. Artificial saliva solutions were used for the tests. Two pH values were used – 7,0 characteristic of a healthy organism and 4,9 - typical for the presence of inflammation. The countersample in the tested friction nodes were Al2O3 balls with a diameter of 6 mm loaded with a normal force of 1 N. The tests obtained showed a strong influence of environmental conditions on the tribological properties of the Ti13Nb13Zr titanium alloy. This applies to both the value of the coefficient of friction and linear wear. In the case of tests carried out under lubrication conditions with an artificial saliva solution at pH 7,0 they were 0,47 and 31,1 μm, respectively; in the case of a fluid at pH 4,9 they were 25 % and 45 % higher (0,62 and 65,6 μm)

    The influence of environmental conditions on the tribological properties of the Ti13Nb13Zr alloy

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    The paper presents the results of tribological tests of the Ti13Nb13Zr titanium alloy - carried out in the conditions of lubrication with liquids simulating body fluids. Artificial saliva solutions were used for the tests. Two pH values were used – 7,0 characteristic of a healthy organism and 4,9 - typical for the presence of inflammation. The countersample in the tested friction nodes were Al2O3 balls with a diameter of 6 mm loaded with a normal force of 1 N. The tests obtained showed a strong influence of environmental conditions on the tribological properties of the Ti13Nb13Zr titanium alloy. This applies to both the value of the coefficient of friction and linear wear. In the case of tests carried out under lubrication conditions with an artificial saliva solution at pH 7,0 they were 0,47 and 31,1 μm, respectively; in the case of a fluid at pH 4,9 they were 25 % and 45 % higher (0,62 and 65,6 μm)
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