Blog Posts

terça-feira, 7 de junho de 2011


Um casco aquecido faz o barco andar mais depressa!

Hot hulls might mean slipperier ships 

By Ben Coxworth

Want to make a ship move faster through the water? Well, one thing that you can do is paint its hull with low-friction or anti-biofouling paint, to keep barnacles and other marine organisms from growing on it. According to Prof. Derek Chan, from the University of Melbourne's Department of Mathematics and Statistics, another approach that should work is to heat that hull up to a temperature of over 100C (212F). His proposed method is based on a 255 year-old principle known as the Leidenfrost effect.

Named for its discoverer, German doctor Johann Gottlob Leidenfrost, the Leidenfrost effect is the phenomenon wherein a liquid, when exposed to a solid that is significantly above that liquid's boiling point, forms an insulating vapor layer between itself and that solid. This is the reason that water droplets dance across a sufficiently-hot skillet, instead of just evaporating on the spot.

... Os futuros Aviões Não-Tripulados vão voar como os outros, mas poderão também bater asas!

Variable-wing prototype points to the future of UAVs

By Noel McKeegan
The role of unmanned aerial vehicles (UAVs) has expanded rapidly in both military and civilian circles over the past decade and although most designs to date are miniature versions of conventional aircraft, we can expect to see much more radical examples emerge in the near future. In developing this next-generation of UAVs engineers are looking to go beyond the limitations of fixed wing and rotary wing aircraft and to do it, they are turning to nature's ultimate flying machines - birds. We've already seen seen flapping-wing micro-aircraft, robotic seagulls and even a design based on a pterodactyl. Engineers at UC San Diego are furthering this approach with research into variable-wing techniques that could result in a bird-like UAV capable of spot landing.

The ultimate goal of the UC researchers is to create a UAV that can both cruise efficiently like a fixed wing aircraft and land on a perch. To achieve this they are studying the wing morphing and flapping techniques used by birds.

E um Foguetão feito por particulares foi lançado, com sucesso parcial...

Homebuilt $70,000 single-person spacecraft tested

By Pawel Piejko

Sending a man to outer space in a homebuilt spacecraft worth US$70,000 may seem like a crazy idea to most of us, but not for a Danish group of enthusiasts who call themselves Copenhagen Suborbitals. Their shoestring-budget single-person flying bullet might have come one step closer to an actual manned flight, thanks to a partially successful test flight last Friday (June 3).

The amateur space engineers prepared everything just as if it was going to be a real flight to space, apart from the passenger, which actually was a crash-test dummy. The rocket HEAT 1-X was launched from a floating ramp called "Sputnik" on the Baltic Sea, carrying a single-person standing capsule known as Tycho Brache (named after a Danish astronomer).
(Sinceramente, se fosse um Potuguês ou um Brasileiro a fazer isto, eram uns maluquinhos, és loirinho e tens olhos azuis, é "aventureiro")...

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