Integration of Hot Tube Gas Forming and Die Quenching of Ultra-High Strength Steel Hollow Parts Using Low Pressure Sealed-Air.

A low pressure sealed-air hot tube gas forming process of ultra-high strength steel tubes was developed not only to change the cross-section of the hollow products by bulging but also to increase the strength of components. Gas-formed components are typically formed by a controlled-gas pressure with extremely high internal pressure, which leads to affected production costs and safety. Moreover, compressing the gas with high pressure requires high energy during its preparation. Therefore, to simplify the internal pressure controlling system and improve the safety factor in gas forming processes, the sealed-air tubes are formed with a quite low initial pressure. The pressure of the sealed air increased with increasing temperature of the air inside the resistance-heated tube, and the bulging deformation was controlled only by axial feeding. The effects of the initial pressure and heating temperature on the bulging deformation and quenchability of the tubes, and the effect of the starting time of axial feeding on the bulging behavior were examined. Consequently, ultra-high strength steel bulged parts were produced even in low initial internal pressure and with the rapid heating of the tubes.

Coordinated movements of the head and body during orienting behaviour in the praying mantis Tenodera aridifolia.

The visual orienting behaviour towards prey in the free-moving mantis was investigated with a high-speed camera. The orienting behaviour consisted of head, prothorax, and abdomen rotations. Coordinated movements of these body parts in the horizontal plane were analysed frame-by-frame. Rotations of these body parts were initiated with no or slight (≤40 ms) differences in timing. The initiation timing of prothorax-abdomen rotation was affected by its initial angle before the onset of orienting. There were positive correlations in amplitude among head-prothorax, prothorax-abdomen, and abdomen rotations. The ratio of these rotations to total gaze rotation was affected by the initial prothorax-abdomen angle before the onset of orienting. Our data suggest that coordinated movements of the head, prothorax, and abdomen during orienting are ballistic events and are pre-determined according to visual and proprioceptive information before the onset of orienting.