1,721,215 research outputs found
Sviluppo ed evoluzione della minipneumatica e della micropneumatica
No full textBLU SMC 11-12, giugno-settembre 199
Equalization techniques for dual redundant electrohydraulic servoactuatorsfor flight control systems
No full text
Thermic Influence on the Dynamics of Pneumatic Servosystems
No full textThe gains values that can be imposed in pneumatic systems controllers are bounded to the restricted actuator bandwidth. That limitation, with low damping and stiffness, due to the air compressibility, seriously affects accuracy and repeatability when varying payload or supply pressures. For modelling and control intent a correct characterisation of the pneumatic actuator natural frequency is indispensable. The aim of this paper is to evaluate how heat exchange process affects the proper characteristics of pneumatic drivers, and in particular their hydraulic stiffness. To this purpose dynamic stiffness had been studied both by imposing in the cylinder's chambers a polytrophic transformation of the fluid with a prefixed index and by employing energy equations. Numerical results obtained by implementing the two formulations for different working conditions are reported and compared in order to point out the ranges in which they overlap, and hence both approaches produce accurate results,or the ones in which there is a difference, and then it is necessary to consider the temperature dynamic
Towards Beijing 2022: Discussion on the growth in size of Paralympic Winter Games in terms of participating data from Örnsköldvik 1976 to PyeongChang 2018
Full text linkParalympic Winter Games (PWG) born in 1976. Across Games, media personnel has increased suggesting an increase in PWG size. However, the growth of PWG from Örnsköldsvik 1976 to PyeongChang 2018 in terms of participating data has not been discussed. This work aims to find if the growth in media coverage comes together with an increase in PWG size in terms of National Paralympic Committee, sports, medal events, and athletes. The presence of trend over PWG editions is evaluated with Mann-Kendall Trend Test and differences among sports and continents with Kruskal Wallis test. Showing a significant monotonic trend, the number of countries (p < .001, β = 0.81) and the number of participating athletes (p < .001, β = 7.40) seem to be good indicators of PWG. These two indicators are good descriptors of PWG size because related to sociocultural and political aspects. In contrast, number of medal events being related to many factors did not show statistically significant trend (p = .95); therefore, this indicator seems to be less appropriate to describe PWG size. If the whole history is considered, slow but significant changes in number of sports (p < .001, β = 0.08) suggest this indicator could be considered in describing Games size
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