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terça-feira, 22 de junho de 2010

Novas Tecnologias...

Um RADAR feito com material caseiro!

A DIY Synthetic Aperture Radar System for $250 
By Rebecca Boyle

Don't Worry, Air Force, It's Just a Model A homemade synthetic aperture radar system takes high-resolution images of small objects, like this model F-14 in maker Gregory Charvat's garage. Gregory Charvat
For about $250, you can make your very own space-age spy tech, following an MIT professor's instructions.
It can capture high-resolution images of small objects -- like a message written in push pins that had been hidden behind a foam plate.
Using a garage-door opener, microwave parts and a cordless drill, Gregory Charvat made a working synthetic aperture radar (SAR) system, the same kind of technology the military and NASA use. Charvat used algorithms to combine the back-scattered radar images into a high-res photos of things in his garage, like a Cannondale bike and a model F-14.
SAR is useful because it combines multiple radar images to create higher-resolution images than would otherwise be possible. There are a couple ways to do it -- by using a single antenna on a moving object, like an airplane or spacecraft, or by using multiple small antennae scattered over a large area. NASA uses SAR to create detailed maps of other planets, and it can be used to map the spread of oil in the Gulf of Mexico, for instance.

Os Grafenos, outra vez, um écran flexível:

Flexible Touch Screen Made with Printed Graphene

Sheets of atom-thick carbon could make displays that are super fast.
By Nidhi Subbaraman

Graphene, a sheet of carbon just one atom thick, has spectacular strength, flexibility, transparency, and electrical conductivity. Spurred on by its potential for application in new devices like touch screens and solar cells, researchers have been toying with ways to make large sheets of pure graphene, for example by shaving off atom-thin flakes and chemically dissolving chunks of graphite oxide. Yet in the thirty-some years since graphene's discovery, laboratory experiments have mainly yielded mere flecks of the stuff, and mass manufacture has seemed a long way away.

See through: Researchers have created a flexible graphene sheet with silver electrodes printed on it (top) that can be used as a touch screen when connected to control software on a computer (bottom).
Credit: Byung Hee Hong, SKKU.

"The future of the field certainly isn't flaking off pencil shavings," says Michael Strano, a professor of chemical engineering at MIT. "The large-area production of monolayer graphene was a serious technological hurdle to advancing graphene technology."

Desta vez, são nanotubos, e melhoram a eficiência das Pilhas, assim como em, 10 vezes mais!
Nanotubes Give Batteries a Jolt
Lithium-ion batteries with nanotube electrodes could go longer between charges.
By Katherine Bourzac

A lithium-ion battery with a positive electrode made of carbon nanotubes delivers 10 times more power than a conventional battery and can store five times more energy than a conventional ultracapacitor. The nanotube battery technology, developed by researchers at MIT and licensed to an undisclosed battery company, could mean batteries that extend the range of electric vehicles and provide longer periods without recharging for electronic gadgets, including smartphones.

E uma pesquisa que promete duplicar o rendimento dos Painéis Solares, utilizando os electrões de alta energia, que até agora não são aproveitados:

Capturing "Hot" Electrons to Double Solar Power

Researchers demonstrate that high-energy electrons lost in conventional solar cells can be captured.
By Katherine Bourzac

There's a limit on the conversion efficiency of a conventional solar cell. No matter how it's tweaked, it can only convert 31 percent of the light that hits it into usable electrical current. That's because there's a broad spectrum of wavelengths in sunlight, and some of it has more energy than the active material in the solar cell can handle. High-energy light hits the active material in a solar cell and knocks loose electrons that have a similarly high energy--then these electrons rapidly lose that excess energy as heat.
Physicists know that if they could capture "hot electrons", they could more than double the efficiency of solar cells. The problem is that they lose their energy in a picosecond. Now, researchers have for the first time demonstrated that it's possible to capture hot electrons while they're still in their high energy state, before that heat loss happens.
Careful design at the nanoscale is key. Instead of a conventional bulk semiconductor, the researchers used quantum dots, because these nanomaterials can confine electrons over a longer timescale. "Nanomaterials can keep electrons electrons hot for a longer period of time, so that you can get them out," says Xiaoyang Zhu, professor of chemistry at the University of Texas, Austin.

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