Science

A computer made using water and magnets can move droplets around inside itself like clockwork, researchers say. The device demonstrates a new way to merge computer calculations with the manipulation of matter, scientists added.

Whereas conventional microelectronics shuffle electrons around wires, in recent years, scientists have begun developing so-called microfluidic devices that shuffle liquids around pipes. These devices can theoretically perform any operation a conventional electronic microchip can.

Although microfluidic devices are dramatically slower than conventional electronics, the goal is not to compete with electronic computers on traditional computing tasks such as word processing. Rather, the aim is to develop a completely new class of computers to precisely control matter. [Super-Intelligent Machines: 7 Robotic Futures]

“The fundamental limits of computation, such as how fast you can go or how small devices can be, are based in how information has to be represented in physical entities,” study co-author Manu Prakash, a biophysicist at Stanford University, told Live Science. “We flipped that idea on its head — why can’t we use computations to manipulate physical entities?”

Current applications for microfluidic chips include serving as miniaturized chemistry and biology laboratories. Instead of performing experiments with dozens of test tubes, each droplet in a lab-on-a-chip can serve as a microscopic test tube, enabling scientists to conduct thousands of experiments simultaneously, but requiring a fraction of the time, space, materials, cost and effort of a conventional laboratory.

But one major drawback of microfluidic devices is that the droplets of liquid are usually controlled one at a time. Although Prakash and his colleagues previously demonstrated a way to control many droplets on a microfluidic chip simultaneously, until now, the actions of such droplets were not synchronized with each other. That makes these systems prone to errors that prevented the devices from taking on more complex operations.

Now Prakash and his colleagues have developed a way for droplets on microfluidic devices to act simultaneously, in a synchronized manner. The key was using a rotating magnetic field, like a clock.

The core of the new microfluidic chip, which is about half the size of a postage stamp, consists of tiny, soft, magnetic nickel-iron-alloy bars arranged into mazelike patterns. On top of this array of bars is a layer of silicone oil sandwiched between two layers of Teflon. The bars, oil and Teflon layers are in turn placed between two glass slides.

The researchers then carefully injected water droplets into the oil; these droplets were infused with tiny magnetic particles only nanometers, or billionths of a meter, wide. Next, the researchers turned on a rotating magnetic field.

Each time the magnetic field reversed, the bars flipped, drawing the magnetized droplets along specific directions, the researchers said. Each rotation of the magnetic field was very much like a cycle on a clock — for instance, a second hand making a full circle on a clock face. The rotating magnetic field ensured that every droplet ratcheted precisely one step forward with each cycle, moving in perfect synchrony.

A camera recorded the movements and interactions of all the droplets. The presence of a droplet in any given space represents a one in computer data, while the absence of a drop represents a zero; interactions among the droplets are analogous to computations, the researchers said. The layout of the bars on these new microfluidic chips is analogous to the layout of circuits on microchips, controlling interactions among the droplets.

So far, the droplets in this device are as little as 100 microns wide, the same size as the average width of a human hair. The researchers noted their models suggest the devices could ultimately control droplets just 10 microns large. “Making the droplets smaller will allow the chip to carry out more operations,” Prakash said.

The researchers now plan to make a design tool for these droplet circuits available to the public, so that anyone can make them.

“We’re very interested in engaging anybody and everybody who wants to play, to enable everyone to design new circuits based on building blocks we describe in this paper, or [to] discover new blocks,” Prakash said in a statement.

Prakash and his colleagues Georgios Katsikis and James Cybulski, both of Stanford University, detailed their findings June 8 in the journal Nature Physics.

References:http://www.livescience.com/

Soundings from 12 PlanetiQ satellites within 24 hours

PlanetiQ has begun testing its new Pyxis weather instrument. Pyxis tracks GPS signals traveling through the atmosphere and makes measurements based on their behavior. PlanetiQ says it can “dramatically improve weather forecasting, climate monitoring and space weather prediction.”

Like Spire, PlanetiQ plans to launch a constellation of microsatellites with weather monitoring technology installed, and Pyxis will be one of the instruments that the PlanetiQ satellites will host. It uses a technique called GPS Radio Occultation (GPS-RO) in which GPS signals in the atmosphere are tracked and converted into measurements of global temperature, pressure and water vapor.

PlanetiQ explains that the data collected will be much like that of weather balloons, but on a greater scale. Using an initial constellation of 12 satellites, the company says it will be able to make over 8 million observations of temperature, pressure and water vapor per day, which equates to more than 10 times the amount of data that current GPS-RO sensors in orbit are able to produce.

GPS-RO is said to be a highly accurate means of forecasting and particularly effective at predicting high-impact weather such as hurricanes and winter storms. Its sensor technology is able to penetrate through clouds and to the lowest layers of the atmosphere where severe weather occurs. Until now, however, there has simply been a lack of GPS-RO data available.

“The Earth’s atmosphere is radically under-sampled at present, especially over the oceans which cover 70 percent of the Earth’s surface,” says PlanetiQ Founder Chris McCormick. “With the speed of innovation in sensor technology, space hardware and launch, the weather forecast will dramatically change for the better in the near future.”

The PlanetiQ initial constellation of 12 satellites is expected to be launched in 2016 and 2017.

References:http://www.gizmag.com/

Researchers pictured with one of the sampling devices used to collect readings of the Pacific Ocean

A new study by MIT has revealed that the quantities of nitrous oxide (N2O), otherwise known as laughing gas, being released by the world’s oceans has been dramatically underestimated. Heightened levels of N2O have the potential to seriously influence the health of our planet’s ozone layer, as the gas is around 300 times more potent than the more prevalent menace of carbon dioxide emissions.

N2O is created, and subsequently largely destroyed, in the boundary between the oxygen saturated layer of water near an ocean’s surface, and the anoxic waters that lie beneath. Nitrogen is initially introduced to the marine environment from a number of sources, including as a runoff from agricultural fertilizer in the form of ammonia. The nitrogen is then consumed by bacteria and marine microbes that produce N2O as a byproduct.

“The denitrifying bacteria that produce N2O also consume it, and it was thought that these two processes are pretty tightly coupled,” states Andrew Babbin, MIT postdoc at the Department of Civil and Environmental Engineering and lead author of a paper on the study. “But that’s not the case in the suboxic layer, resulting in leftover N2O that leaks away to the surface.”

Prior to the study, it was not well understood just how much of the gas was escaping the ocean and entering the environment above, and the potential harm that this could be inflicting on our planet’s fragile atmosphere.

Babbin and his team were able to gain a better understanding by making a computer analysis of water samples from various depths at three different locations in the eastern tropical North Pacific, in order to determine denitrification rates for the region.

Results appear to show that previous estimates on the quantities of N2O escaping the oceans may have been off by as much as a factor of 10. By making use of recent climate models, Babbin and his team estimate that our world’s oceans could be producing as much as 4 million metric tons of N2O per year

This output of the harmful gas has the potential to seriously harm Earth’s ozone layer, and it is predicted that production will rise as agricultural growth continues, introducing ever more nitrogen into Earth’s oceans.

References:http://www.gizmag.com/

The nano-spirals emit a very specific optical signature that could be recognized by a barcode reader-like device

Researchers from Vanderbilt University in Nashville, Tennessee have created the world’s smallest continuous spirals. Made from gold, the spirals exhibit a set of very specific optical properties that would be difficult to fake, making them ideal for use in identity cards or other items where authenticity is paramount.

The team used electron-beam lithography to create the minuscule gold spirals, subsequently testing them using ultrafast lasers at Vanderbilt University and the Pacific Northwest National Laboratory in Washington.

It’s not the first time that microscopic spirals have been studied by researchers, but previous efforts have focused on spirals made from individual nanoparticles rather than solid bars, like drawing in dots of ink rather than full lines. The nano-spirals in the new study are also much smaller than those in prior research, with a square array featuring some 100 nano spirals measuring less than one hundredth of a millimeter wide.

Once fabrication was complete, the team began testing the optical properties of the spirals. Each individual spiral is smaller than the wavelength of visible light, affording it some interesting and difficult-to-fake properties.

When the researchers shone an infrared laser on them, an effect known as frequency doubling or harmonic generation occurred, causing a visible blue light to be emitted. Essentially, as the light hits the spirals, it’s absorbed by electrons in structure, and forced along the arms of spiral. So much energy is absorbed during the process that blue light is emitted at the center of the spiral, with double the frequency of the incoming infrared light.

Previous to the research, the strongest known frequency doubler was a synthetic crystal called beta barium borate. The spirals fabricated in the new study are much more effective at throwing out the high-frequency light than the crystal, producing four times as much blue light during testing.

The researchers also found that the spirals exhibited a very distinctive response to polarized light, which is light that vibrates in a single plane. The amount of emitted blue light varies depending on the angle of the polarized beam – something that scientists could measure and use as a stamp of material authenticity.

Furthermore, when rotating polarized light was shone on the spirals, similarly unique emissions were observed, with the amount of blue light varying depending on whether the circularly polarized light was rotating to the left or to the right.

Overall, the nano-spirals’ unique response to infrared light would make them a good fit for use on identification or credit cards. The spiral arrays would be too small to see with the naked eye, but could be detected by a device akin to a barcode reader.

The team has already experimented with placing small arrays of nano-spirals on a glass substrate, but it would also be possible to fabricate them on other materials such as plastic or paper. The spirals themselves could also be constructed from different materials including silver and platinum. Given the small amount of metal involved, the costs of using such precious materials would actually be very low.

References:http://www.gizmag.com/