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Selasa, 06 Desember 2011

Turning Hydrogen Gas Into Metal


Today in relatively obscure but nonetheless meaningful scientific pursuits: two researchers at the Max-Planck Institute claim to have turned hydrogen into metal. That may seem unremarkable, but the fact is hydrogen--being an alkali metal--should exhibit the qualities of a metal under the right circumstances. Yet no one has ever coaxed the universe’s most abundant element into showing metallic qualities until now. Perhaps.
This all depends on how you qualify the term “metal.” There are some boilerplate qualifiers: Metals should conduct electricity and heat somewhat well, they should be malleable to some degree, and it makes sense that they should exist as solids under some circumstances.



But though many have tried, none have been able to make hydrogen behave like a metal under these criteria. Mikhail Erements and Ivan Troyan claim in a paper published in Nature Materials that they’ve done exactly that.
First, they placed some hydrogen in an alumina-epoxy gasket and placed that within a diamond anvil cell. This allowed them to test the opacity and electrical resistance of their sample via laser and electrodes, respectively.



Then, at room temperature, they dialed the pressure up to 220 gigapascals, at which point their sample became opaque and began to show conductive properties. In the next phase of their experiment, they also dialed down the temperature to roughly -400 degrees while upping the pressure to 260 GPa. Here, electrical resistance increased by 20 percent.

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This, they claim, is hydrogen exhibiting metallic properties.
Now, other researchers are going to have to replicate the se results before they can be described as truly meaningful. And then peer reviewers are going to have to hash out whether or not these qualities truly constitute “metallic” characteristics. What is most interesting is that they made hydrogen gas conductive at room temperature by applying pressure. Materials scientists have long been looking for superconductors that can move electricity over distances without losing so much of it as waste. Perhaps hydrogen was right there staring them in the face all along.

Jumat, 02 September 2011

The Urban Future



Architect Mitchell Joachim points out, frequently and without prompting, that his futuristic proposals are always based on existing technologies. No wonder he feels the need to say it. Consider some of his ideas: jetpacks tethered together in swarms, houses grown from living trees, low-altitude blimps prowling New York City with chairs hanging below them for pedestrians to hop on and off (24/7 ski lifts on Broadway!), and WALL-E-like machines that erect buildings and bridges from recycled waste. 


For Joachim, a 39-year-old professor of architecture at New York University, with graduate degrees from MIT, Harvard and Columbia, these concepts aren’t Hollywood fluff but designs that could come to life today. Take his concept for waste-building machines, which he calls Rapid Re(f)use. Instead of the cubes of cardboard, plastic or steel that current recycling balers produce, Joachim’s robots would grind and compress waste into I-beams, cruciform columns or even furniture components. The structures would be pressed or melted into shape or wrapped with metal bands, which is what recycling plants do now. All that would change is the shape—like switching the mold on a Play-Doh press, but on an industrial scale. “We could do it yesterday,” Joachim insists.


His vision falls under the banner of Terreform ONE, a nonprofit design collective that Joachim co-founded to explore sustainable, fully integrated urban planning. If the same people who design the roads also design the cars, he says, and the same people who create the suburbs also plan for ways to feed and transport residents, our cities will become healthier, friendlier and more sustainable.


The group imagines how future cities might best serve their citizens on a large scale and then experiments with the small-scale materials and designs that it would take to make it happen. To this end, Terreform ONE hosts TerreFarm, an annual summer gathering of architects and scientists who develop new urban farming techniques. 

For several weeks this summer, TerreFarm will convert a Brooklyn rooftop into a testbed for modular growing methods, designs for maximizing available sunlight, and ultra-lightweight soil mixes essential for rooftop gardens. They will also build full wall sections of Joachim’s Fab Tree Hab, his proposal to create “living” homes by grafting trees together around scaffolds and growing them on-site.


Joachim’s other plans tend to focus on mobility, since transportation both shapes and is shaped by urban design. In his vision, individual cars would be replaced by car-share systems that function like luggage carts at an airport. Pay, step into a smart car that communicates with the city grid, drive to your destination, and leave the car there. The cars would have soft, springy exteriors, inflatable protective bladders and transparent foil, which would enable them to bump together as they traveled in flocks.

“The idea of sharp metal boxes is just done,” Joachim says. “We design cars with the principle that no one would ever die in a car accident again.”


Joachim’s blimps would move like trolley cars. Their routes would be set by funicular cables, and they would float slowly enough that pedestrians would be able to hop on and off hanging chairs dangling above the ground. Unlike a trolley car, though, the blimps would also be able to cross rivers, gorges and other geographic features without bridges.


His jetpack designs are not the retro-futuristic rocket belts of the 1960s but more like the lightweight ducted-fan jetpacks scheduled to go on sale later this year from Martin Aircraft Company. For efficient commuting, Joachim’s jetpacks—soft and flexible like his cars—would be towed in flocks by a plane or blimp. “Bump and glide,” as Joachim describes it. From there, individuals could break off, power up, and fly safely to their homes or offices—like subways in the sky. “It’s hard to find people who don’t want to be moving around in jetpacks in 20 years,” he says. “As an architect, then, I’m responsible for thinking about what the implication of the jetpack is on the future city.”

Joachim’s willingness to forgo lucrative commercial projects in favor of running a nonprofit dedicated to the reimagining of a future he won’t even be around for is, say his colleagues, exactly what makes him so vital. Traditionally, “cities are built incrementally by real-estate interests,” says Richard Sommer, the dean of architecture at the University of Toronto. “What’s important about Mitchell’s work is that he [takes] a visionary approach.”


The vision part involves looking 150 years down the road and planning for how cities will have to operate within the environment if civilization is to endure. Even if the technologies exist today, Joachim says, no one can change the city tomorrow. “Once we heard about cellphones, it was about seven years before we started dropping the landline,” he says. “It took about 15 years before you could buy a hybrid car on every lot. It takes around 40 years to produce a large shift in the way buildings are constructed. Entire cities? It’s 100, 150 years.”


In the meantime, Joachim is busy producing the stuff that will get us there, whether it’s growing living walls, planting organic lettuce on urban rooftops, or making sure that when your grandkids are ready for their first jetpacks, their cities will be too.

by "environment clean generations"

Sabtu, 27 Agustus 2011

Liquid Metal Shoes



We're tired of hearing vague promises about how our shoes will one day be able to power our gadgets, but this particular vague promise got our attention for two reasons: one, it involves liquid metal, and two, the amount of power that it can harvest from walking is ridiculously huge.

Most systems that harvest energy from movement use piezoelectrics. That's fine, there's nothing wrong with that, except that piezoelectrics generally produce power measured in milliwatts. Milliwats of power can potentially run low-power sensors, trickle charge a battery, or (if you're lucky) run something like an iPod shuffle.

Researchers at UW-Madison have been working on an energy harvester that they say can deliver watts of power. And not just one or two watts, but up to 10 or 20. This is a huge amount of power to get from a "free" energy harvester; we're talking thousands of times more powerful than the current generation of pizeoelectrics. An iPhone, for example, typically consumes under five watts. This means that 10 watts could power two iPhones, and 20 watts could power four of them! Four iPhones! Imagine the possibilities!

To get this much power, the researchers ditched the piezoelectric idea entirely, and instead invented a new energy harvesting processes they're calling "reverse electrowetting." A liquid metal (in this case, it's something called galinstan which is non-toxic and used in thermometers) is stored in pouches at the heel and sole of a shoe. As you walk, you pump the nano-sized droplets of the liquid metal through tiny channels, creating a electricity which is stored in a battery at the center of the shoe. It's a completely sealed system that requires no maintenance: all you have to do is walk.

To take advantage of all this power, one option is to just kludge a USB port into your shoe and plug in directly, but there may be more creative ways to go about making your devices last longer. For example, your cellphone expends much of its power broadcasting intensively enough to reach the closest cell tower. If instead you had a sort of miniature self-powered cell tower in your shoe that could amplify you're phone's signal, your phone would only have to broadcast a few feet instead of tens of miles, boosting its battery life by a factor of 10 or more.

The company that the UW-Madison researchers founded to commercialize this technology is called InStep NanoPower. They're currently working on a prototype which should be ready in a few years, and a product for both the military and civilian markets will follow. Ultimately, the cost of the embedded harvester is not expected to exceed the cost of the footwear itself, meaning that at the outside, a pair of shoes might get twice as expensive with the harvester inside. But considering how much power this thing can supposedly generate, I'd say that it would definitely be worth the premium to never have to worry about recharging your stuff again.

As long as you get off your ass and walk around every once in a while, that is.

by "environment clean generations"