New Actuators for Aircraft, Space and Military Applications

Abstract: Actuation is used in all vehicles (aircraft, spacecraft, ground vehicles, etc) to control the position and/or attitude of the vehicle, and also to deploy or retract equipment, particularly for embedded optic instruments (cameras, telescopes). As such, the actuation is a safety critical system, particularly when humans could be catastrophically affected by failures within the system. Applications for actuation are flight controls, landing gear, rotors, suspension, antennae steering, valves, scanning, positioning using hydraulic, electromechanical, magnetic and piezo actuators. In aircraft there is a common goal to reduce the number of hydraulic actuators in vehicles and eventually to replace them completely by electric actuators. The interest for smart suspensions is pushing magnetorheological fluids (MRF) actuators. In UAV, MAV and microsatellites, actuators key drivers are often miniaturisation and low power. Embedded optic & space instruments are leading to improved piezo actuators and motors

Highly deformed 40^{40}Ca configurations in 28^{28}Si + 12^{12}C

The possible occurrence of highly deformed configurations in the $^{40}$Ca di-nuclear system formed in the $^{28}$Si + $^{12}$C reaction is investigated by analyzing the spectra of emitted light charged particles. Both inclusive and exclusive measurements of the heavy fragments (A $\geq$ 10) and their associated light charged particles (protons and $\alpha$ particles) have been made at the IReS Strasbourg {\sc VIVITRON} Tandem facility at bombarding energies of $E_{lab} (^{28}$Si) = 112 MeV and 180 MeV by using the {\sc ICARE} charged particle multidetector array. The energy spectra, velocity distributions, and both in-plane and out-of-plane angular correlations of light charged particles are compared to statistical-model calculations using a consistent set of parameters with spin-dependent level densities. The analysis suggests the onset of large nuclear deformation in $^{40}$Ca at high spin.Comment: 33 pages, 11 figure

De–excitation of compound nuclei with A around 56: reduction of the emission barriers for protons and alpha particles

This paper contributes to the discussion on the phenomena of the enhanced emission of low–energetic charged particles during compound nuclei decay. The decay of compound nuclei $^{52}$Fe, $^{56}$Ni, and $^{59}$Cu was studied. Energy spectra and emission angles of evaporated charged particles were measured in coincidence with gamma rays to determine the corresponding evaporation residue nucleus. Additionally, evaporation residue distributions were determined with the Munich rf recoil spectrometer. In this way, detailed channel–specific evaporation data were obtained for theoretical analysis. We extracted evaporation barriers and compared them with corresponding fusion barriers. The main result was revealed to be a lowering of the evaporation barrier for protons and alpha particles relative to the fusion barriers. But the observed effect is not as intensive as reported in recent studies