Purpose -The purpose of this paper is to present the advantages of computer-aided design/rapid prototyping (CAD/RP) usage in designing and manufacturing of the core models used for precise casting with direct and single solidification of aircraft engine turbine blade cores. Design/methodology/approach -The process of modelling three-dimensional CAD geometry of research blade in relation to the model of the core was presented with different wax types used in the RP technique. Findings -The geometry of the blade model has been designed in a way which allows making a silicon mould on the basis of a base prototype in the process of rapid tooling (RP/RT). Filing by different wax types was investigated in mean of the impact on filling accuracy of the mould cavity. Originality/value -The resulting models were used to make ceramic moulds and carry further work on the development of casting technology in the process of directional solidification and single crystal solidification of core blades of aircraft engines.
In this article the research related to the scope increase of incremental technology in machine industry is presented. Those technologies were used for the manufacture of components from polymeric materials with torque loaded such as: shafts, clutches of gear hubs and other elements of the propulsion system in which torque is transferred. To analyze the properties of the manufactured elements the original testing stand was designed and a series of preliminary torsional strength tests of the gear shaft fittings obtained using additive techniques have been carried out. On the basis of the obtained results it was stated that there is a clear influence of the printing plane in the applied incremental technologies [SLS (selective laser sintering) and FFF (fused filament fabrication)] on the torsion resistance of the obtained elements. The properties of the shafts also depend on the type of polymeric materials which they were made of.
This work is a continuation of the publication [1], in which the torsional strength tests of samples made of polymer materials, loaded with torsional moment, which more and more often can be made with the use of incremental technologies, were carried out. The designed proprietary test stand, which was described in the publication [1], was used. A series of preliminary studies on the torsion of fittings with spline connections obtained using additive techniques were carried out. It was found, that a additive technologies have a clear impact on the torsional strength of the tested machine components, including the placement of the prototype relative to the 3D printing plane or the method of processing polymer material.
In this work, on the example of a spline connection, the effect of 3D printing on the structure of machine elements made of polymeric materials after a torsion test was investigated. A clear influence of the type of polymer and the printing direction in the applied incremental technology [FFF (Fused Filament Fabrication) also known as FDM (Fused Deposition Modeling)] on the structure of the obtained elements was observed.
The article presents a multidimensional comparative analysis of the drops in the number of passengers transported by rail in 28 European countries on a quarterly basis in 2012-2020 in terms of the impact of the COVID-19 pandemic and economic security. Data collected from Eurostat on the number of passengers transported by rail in 28 European countries were aggregated and further analyzed in order to emphasize the regularities governing them. The research has observed a growing trend on an annual and quarterly basis in the total number of passengers transported by rail in 28 European countries in 2012-2019. Additionally, in the unnamed (quarterly) data, a quarterly seasonality was detected. Since 2020, there have been declines in the number of passengers transported by rail in all of the 28 European countries considered. The declines were subjected to a comparative analysis, adopting various criteria, in order to assess which countries were most affected by the COVID-19 pandemic in terms of rail passenger transport.
The subject of the article is the economic analysis of passenger transport at polish airports before and during the COVID-19 pandemic. Air transport is considered as an integral part of polish transport system, which significantly increased the dynamism of service development, after joining the European Union by Poland. Along with the globalization of production and international economic exchange, the demand for efficient communication between airports is increasing. During the initial phase of the pandemic, the passenger transport had stopped altogether and afterwards was significantly weaker compared to the times prior to the pandemic. It was caused by the closure of borders and partial suspension of transport connections. One of the key tasks for airports is the provision of passenger service at the appropriate level. The level of passenger service can be considered satisfying his needs in terms of quality, punctuality, comfort and reliability. Important issues in ensuring the appropriate quality of service is the possibility for the passenger to choose more than one airport, as well as the profit from non-aviation activities. One of the most important factors influencing the passenger service process is the activity of air carriers, staff and management of the airport, as well as services located within the airport. As a consequence of spreading the coronavirus (COVID-19) worldwide and the actions taken by the authorities, the demand for international traveling at polish airports ceased to exist at the time. The article presents an economical analysis of passenger transport before and during the pandemic.
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