You are browsing the archives of 2010 January.

A network with crystalline bundles of filaments. Credit: Yuri S. Velichko.

A team from Northwestern University reports in the new issue of Science about the role that X-rays can play in crystal formation. The researchers say they accidentally discovered that X-rays can trigger the formation of a new type of crystal that is composed of charged cylindrical filaments. These crystals are ordered like a bundle of pencils experiencing repulsive forces.

They hope their work will expand the use of X-rays from not just an analytical tool but also a method to control the structure of materials.

In a NU press release, Samuel Stupp, one of the paper’s authors, describes what the group thinks is going on with the X-rays. “The filaments are charged so one would expect them to repel each other, not to organize into a crystal. Even though they are repelling each other, we believe the hundreds of thousands of filaments in the bundles are trapped within a network and form a crystal to become more stable,” says Stupp, who is a professor of chemistry, materials science and engineering and medicine.

The discovery happened when members of Stupp’s research team, working on a separate organic project, zapped a solution of peptide nanofibers with synchrotron X-ray radiation. Unexpectedly, the solution turned opaque. “There was a dramatic change in the way filaments scattered the radiation,” says coauthor Honggang Cui. “The X-rays turned a disordered structure into something ordered - a crystal.”

The group theorizes that the X-rays increase the charge of the material and causes a hexagonal stacking of filaments. They say that because of repulsive forces, the filaments are positioned far apart from each other, with as much as 320 angstroms separating the filaments.

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I’m currently in Daytona Beach, Florida for the ICACC’10 conference. One of the keynote speakers was the University of Bayreuth’s Walter Krenkel. Krenkel invented a liquid silicon infiltration process for the manufacture of SiC-based ceramics for disks and pads in high performance brake systems.These brakes are hard and heat resistant, plus their light weight translates into less spun mass at the wheels.

The downside is that ceramic brake systems are still expensive. So, while it will still be a while before these brake systems make it into the typical Ford or Toyota. Nevertheless, ceramic composite brakes are common in F1 racing and increasingly in high-performance, luxury-level cars.

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By homey Robert Pollard/Guided By Voices. He was everyone’s favorite 4th-grade teacher.

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Having just announced that they will be spending $550 million converting a Detroit SUV factory into a hybrid and electric vehicle factory, Ford Motors has announced a further investment of $450 million into electric cars and batteries.

Part of the money will be used to move lithium-ion battery production from its current location in Mexico to Michigan. Ford’s executive chairman, Bill Ford, said they were moving to address environmental, energy and economic issues.

Jennifer Granholm, the outgoing state governor, said that “vehicle electrification is part of our ongoing strategy to diversify Michigan´s economy and make the state a center for green and advanced manufacturing.”

The company has outlined plans to bring several vehicles to market over the next three years including the Ford Transit Connect electric commercial van, the Ford Focus electric passenger car and a hybrid based on the C-car platform.

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Live Science reported that researchers have built a new super-small “nanodragster” that could speed up efforts to craft molecular machines.

“We made a new version of a nanocar that looks like a dragster,” said James Tour, a chemist at Rice University who was involved in the research. “It has smaller front wheels on a shorter axle and bigger back wheels on a longer axle.”

The vehicle is about 50,000 times thinner than a human hair and is pushed along by heat or an electric field.

Spherical molecules called buckyballs made of 60 carbon atoms each serve as the big rear wheels. Due to chemical attractions, these wheels nicely grip the “dragstrip,” which is made of a superfine layer of gold rather than pavement. For the front wheels, the scientists opted for a less sticky compound, p-carbonane.

Tour’s group built nanocars before with buckyballs as all four wheels, but these autos hug the road too tightly and require temperatures around 400 F to get rolling. Nanocars with all p-carbonane wheels, on the other hand, slip and slide as if on ice, said Tours, making them difficult to image and study.

By incorporating both wheel types, the nanodragster can cruise at lower temperatures with greater agility and range of motion.

To make the new nanodragster, Tour’s team started with a previously built, off-the-shelf short axle and front wheel unit in their lab, which is sort of a nano-Monster Garage. They then chemically hooked this up to a pair of aligned hydrocarbon molecules called phenylene-ethynylene-the vehicle’s chassis. The rear axle came next and finally the buckyball wheels went on.

Once the new nanocar gets rolling, it can reach speeds of up to nine nanomiles, or 0.014 millimeters (.0005 inches), per hour, which is relatively fast for their size, said Tour.

The tiny hot rods can also do tricks. “Because the front wheels don’t stick to the surface as strongly, they’re more prone to lift up, so [the nanodragster] does seem to pop a wheelie at times,” Tour told Top Ten Reviews.

By learning how to drive nanovehicles, Tour hopes to pave the way for small but technologically useful structures, such as electronics, that could be built atom-by-atom.

The research appeared in a recent issue of the journal Organic Letters.

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