One of the weaknesses multi-rotor unmanned aerial vehicles (UAVs) or vertical take-off and landing aircraft is that they need a flat surface to make safe landing. In order reduce impact this weakness, it inevitable add systems will give UAV some additional capabilities related capability. study, four-arm adaptive gear designed kinematically analyzed for UAV. The adaptability feature achieved by...

In this paper, an active control structure used piezoelectric stack actuator is built to suppress vibration due to internal incentive in gear transmission. Because the gear system is timevariant and unknown, an offline modeling technique is unable to tracking the changes in the secondary path, an adaptive filter algorithm used online secondary path modeling method is proposed to the active vibr...

The NASA goal of reducing external aircraft noise by 10 dB in the near-term presents the acoustics community with an enormous challenge. This report identifies technologies with the greatest potential to reduce airframe noise. Acoustic and aerodynamic effects will be discussed, along with the likelihood of industry accepting and implementing the different technologies. We investigate the lower ...

The coastal waters off Western Iberia are an important fishing ground and a marine megafauna foraging area. Overlap between fishery target species the diet of several air breathing can lead to negative interactions consequently conservation economic issues. This work aimed assess (cetaceans, birds, turtles) – through face-to-face interviews fishers local artisanal fisheries fleets in landing si...

Introduction: The Phoenix probe landed on the northern plains of Mars (68.2°N, 234.2°E) on May 25, 2008, and the landscape seen on the first images acquired on the surface confirmed what was already known since the HiRISE camera began scrutinizing the Martian surface with unprecedented detail, that the existence of polygonal terrains is a predominant feature in that area [1][2]. The polygons ob...

Over 50% of the total bigeye tuna (BET) landed in the Western Central Pacific Ocean is caught incidentally in the purse seine fishery and sold for canning at prices less than US$2/kg. The remainder is landed in longline fisheries directed at BET and sold as fresh or frozen tuna at prices greater than US$10/kg. The combined fishing mortality by all gears will soon reduce the BET biomass in the P...

When a spacecraft lands, a large shock load can lead to undesirable responses such as rebound and tripping. The authors previously discussed the problem of controlling these shock responses using momentum exchange impact dampers. An active/passive hybrid momentum exchange impact damper, which included an active actuator, was proposed. Themomentum exchange impact dampers’ performances are evalua...

This paper discusses recent findings in ongoing research on the visual cues that pilots use when landing airplanes. An overview is given of the many visual cues that have been proposed in literature. Some are widely accepted as ‘important cue’ in a certain phase or for a certain decision, others are controversial. Specifically the cues used to time the flare maneuver are discussed in this contr...