Science and Technology: 2013

Tuesday, 26 February 2013

New Electronic Display to Be Used on Clothes and Beer Cans

One of the latest inventions in the field of light emitting devices might change the way people light their homes and design clothes. The device represents a thin film of plastic able to conduct electricity and create solar power.

Scientists working on the international project are looking forward to bring the organic light emitting devices to the masses. Thus the invention could significantly cut costs by billions of dollars each year.

Due to the fact that the organic light emitting devices are very thin and flexible, electronic display screens could be easily created on nearly every material, thus, for example, clothing could, for the first time in history, display specific electronic information.

There are various ways of using the this OLED, like for example change the color of clothes, beer can would be able to display various sports results. In addition the OLED is much more efficient than the light bulb used today.

Currently these devices are applied in mobile phones and MP3 players. However, such OLED is not quite reliable for large TV or computer screens.

In order to make the device more efficient so later to launch it to mass market, the international consortium of researches, Modecom, headed by the University of Bath, United Kingdom, started a three-year project which will cost about $1,700,000.

Modecom comprises 13 groups from 9 universities and two companies. There are three groups from the United Kingdom, six groups from the United States and one group from China and one each from three European countries including Belgium, Italy and Denmark. Only the European countries and China will receive financial aid from the European Union.

The coordinator of Modecom is Dr Alison Walker, who represents the Department of Physics of the University of Bath. "This is a long-term project, and the contributions of many scientists are needed for its success ... Success in achieving the goals of cheap, efficient and long lasting devices is essential as we must do everything we can to reduce our energy costs," he stated.

Solid State Batteries

Ann Marie Sastry wants to rid electric vehicles' battery systems of most of the stuff that doesn't store energy, such as cooling devices and supporting materials within the battery cells. It all adds up to more than half the bulk of typical lithium-ion-based systems, making them cumbersome and expensive. So in 2007, she founded a startup called Sakti3 to develop solid-state batteries that don't require most of this added bulk. They save even more space by using materials that store more energy. The result could be battery systems half to a third the size of conventional ones.

Cutting the size of a battery system in half could cut its cost by as much as half, too. Since the battery system is the most expensive part of an electric car (often costing as much as $10,000), that would make electric cars far cheaper. Alternatively, manufacturers could keep the price constant and double the 100-mile range typical of electric cars.

The limitations of the lithium-ion batteries used in electric cars are well known. "Most liquid electrolytes are flammable. The cathode dissolves," says Sastry. Keeping the electrolyte from bursting into flames requires safety systems. And to extend the electrode's lifetime and prevent heat buildup, the battery must be cooled and prevented from ever fully charging or discharging, resulting in wasted capacity. All this adds bulk and cost. So Sastry wondered if she could make a battery that simply didn't need this much management.

Sastry's solid-state batteries are still based on lithium-ion technology, but they replace the liquid electrolyte with a thin layer of material that's not flammable. Solid-state batteries are also resilient: some prototypes demonstrated by other groups can survive thousands of charge-discharge cycles. And they can withstand high temperatures, which will make it possible to use materials that can double or triple a battery's energy density (the amount of energy stored in a given volume) but that are too dangerous or unreliable for use in a conventional lithium-ion battery.

To make solid-state batteries that are practical and inexpensive to produce, Sastry has written simulation software to identify combinations of materials and structures that will yield compact, reliable high-energy devices. She can simulate these materials and components precisely enough to accurately predict how they will behave when assembled together in a battery cell. She is also developing manufacturing techniques that lend themselves to mass production. "If your overall objective is to change the way people drive, your criteria can no longer only be the best energy density ever achieved or the greatest number of cycles," she says. "The ultimate criterion is affordability, in a product that has the necessary performance."

Although it may be several years before the batteries come to market, GM and other major automakers, such as Toyota, have already identified solid-state batteries as a potentially key component of future electric vehicles. There's a limit to how much better conventional batteries can get, says Jon Lauckner, president of GM Ventures, which pumped over $3 million into Sakti3 last year. If electric vehicles are ever to make up more than a small fraction of cars on the road, "something fundamental has to change," he says. He believes that Sakti3 is "working well beyond the limits of conventional electrochemical cells."

Sastry is aware that success isn't guaranteed. Her field is something of a technological battleground, with many different approaches competing to power a new generation of cars. "None of this is obvious," she says.

Cars Run On battery

In August 2009, President Obama announced a $2.4 billion grant program designed to create an electric vehicle battery industry in the United States. Three years on, the factories funded by those grants are sitting idle or operating well below their originally intended capacity.

The problem is simple. People aren't buying enough electric cars, and most of those that are being sold contain batteries made by established battery makers in Asia.

It's still early days for electric vehicles, but the idle factories point to the difficulty of starting a new high-tech industry from scratch.

The first chart, top left, shows the gap between the planned capacity for 2013 and the demand for batteries, based on estimates from Menahem Anderman at the consulting firm Advanced Automotive Batteries. The projected shortfall will happen even if the number of vehicles that use those batteries grows dramatically between 2012 and 2013, as is shown in the estimates in the second chart, below.

Some grant recipients have had to scramble to find customers. Dow Kokam, for example, which was awarded a grant of $161 million, has lined up a few customers, but no major automakers yet. Last week, it announced it would supply batteries for a small electric vehicle made by the French automaker Lumeneo. The batteries are less than a third of the size of those in full-size electric vehicles, such as the Nissan Leaf.

Even grant recipients that do have agreements to supply major manufacturers are struggling. LG Chem, for example, supplies battery cells for Chevrolet's Volt. It built a factory in Holland, Michigan, with the help of an award of $151.4 million. But the plant isn't producing any batteries yet. Volt sales have been lower than originally anticipated, and the battery cells for the Volt so far come from Korea, where LG Chem is based; even there, it's still operating at only 20 to 30 percent of capacity, Anderman says. Companies in Asia had a head start on U.S. batteries companies because of their existing capacity for producing batteries for portable electronics or hybrid cars.

How Solar-Based Microgrids Could Bring Power to Millions

The village of Tanjung Batu Laut seems to grow out of a mangrove swamp on an island off the coast of Malaysian Borneo. The houses, propped up over the water on stilts, are cobbled together from old plywood, corrugated steel, and rusted chicken wire. But walk inland and you reach a clearing covered with an array of a hundred solar panels mounted atop bright new metal frames. Thick cables transmit power from the panels into a sturdy building with new doors and windows. Step inside and the heavy humidity gives way to cool, dry air. Fluorescent lights illuminate a row of steel cabinets holding flashing lights and computer displays.

The building is the control center for a small, two-year-old power-generating facility that provides electricity to the approximately 200 people in the village. Computers manage power coming from the solar panels and from diesel generators, storing some of it in large lead-acid batteries and dispatching the rest to meet the growing local demand. Before the tiny plant was installed, the village had no access to reliable electricity, though a few families had small diesel generators. Now all the residents have virtually unlimited power 24 hours a day.

High-Speed Materials Discovery

Electric cars could travel farther, and smart phones could have more powerful processors and better, brighter screens, thanks to batteries based on new materials being developed by San Diego–based Wildcat Discovery Technologies.

The company is accelerating the identification of valuable energy storage materials by testing thousands of substances at a time. In March of last year, it announced a lithium cobalt phosphate cathode that boosts energy density by nearly a third over current cathodes in popular lithium-ion phosphate batteries. The company also unveiled an electrolyte additive that allows batteries to work more reliably at higher voltages.

Monday, 25 February 2013

MARS

Black Hole Unleashes Supermassive Belch

While innocently surveying the Cosmos, astronomers serendipitously stumbled across a particularly uncouth galaxy. NGC 660 unleashed an epic belch, an event that we could see 44 million light-years distant.

This event emanated from the galaxy’s core, around the likely location of a supermassive black hole.

To determine that the event was in fact triggered by NGC 660′s central supermassive black hole and not a supernova, astronomers used the High Sensitivity Array (HSA) — a global network of radio telescopes including the Very Long Baseline Array (VLBA), the Arecibo Telescope, the National Science Foundation’s 100-meter Green Bank Telescope, and the 100-meter Effelsberg Radio Telescope in Germany. They found five bright spots of radio emissions near the galaxy’s core and not an expanding ring of material that would be synonymous with an exploding star.

“The discovery was entirely serendipitous. Our observations were spread over a few years, and when we looked at them, we found that one galaxy had changed over that time from being placid and quiescent to undergone a hugely energetic outburst at the end,” Robert Minchin, of Arecibo Observatory in Puerto Rico, said in a statement.

“High-resolution imaging is the key to understanding what’s going on,” added Emmanuel Momjian, of the National Radio Astronomy Observatory (NRAO). “We needed to know if the outburst came from a supernova in this galaxy or from the galaxy’s core. We could only do that by harnessing the high-resolution imaging power we get by joining widely-separated radio telescopes together.”

The HSA employs the help of many radio antennae across the globe, all working in concert — as an interferometer — to gain incredibly high-resolution imagery deep inside the core of the galaxy. For example, in the above image, the radio insert represents just a single pixel of the optical image of NGC 660.

So why did the supermassive black hole in the galaxy’s core belch? As we’ve learned from observations of the black hole behemoth in the center of the Milky Way, black holes consume anything that strays too close. Any dust, gas, planets, aliens or stars that fall into the black hole’s gravitational well will be ripped apart and pulled into a violent accretion disk surrounding the black hole’s event horizon.

Through processes that aren’t fully understood, some of this matter is accelerated and ejected from the black hole’s poles at relativistic speeds, generating superheated streams of gas. In the case of NGC 660, its black hole is likely feeding, erupting huge streams of radio-emitting gas, but the pattern of ejected gas isn’t a simple case of two hot spots blasting from two poles; there appears to be five hot spots.

“The most likely explanation is that there are jets coming from the core, but they are precessing, or wobbling, and the hot spots we see are where the jets slammed into material near the galaxy’s nucleus,” said Chris Salter, of Areceibo Observatory. “To confirm this, we will continue to observe the galaxy with the HSA over the next few years.”

Ghost Illusions Hide Objects in Plain Sight

The original metallic object (a) is covered by a device that scatters incoming light waves, resulting in two ghost images on either side of the morphed object (b); the metallic object is shrunk here in the middle of two wing objects (c).

Ghostly illusions could one day help disguise military aircraft for greater stealth, researchers say.

In the last eight years or so, scientists have discovered cloaking devices are possible, which can bend and twist light completely around objects, rendering them invisible. Cloaking devices that work against other kinds of waves are possible as well, such as theacoustic waves used in sonar.

However, such cloaks are usually limited to working against narrow ranges of frequencies for various types of waves. An international team of physicists instead explored devices that could potentially work against wide bands of frequencies, generating illusory ghostsas disguises.

Hydrogen Fuel Made with Sunlight and Zinc

Hydrogen is the most abundant element on Earth. And it’s potential as a fuel could revolutionize the energy market because using it doesn’t produce any emissions. Zero. Unfortunately, it’s lightweight gas and rises into the atmosphere, which means its rarely found in its pure form. And making making it produces emissions.

Erik Koepf, a mechanical engineering PhD student at the University of Delaware, may have found a way to make hydrogen fuel cheaply, using only sunlight, zinc oxide and water.

Wireless energy transfer

The wireless transfer of information has brought a lot of convenience to life. Yet people are not going to stop. The dream of a day when electric cables, outlets and adapters are no longer necessary has driven the research of wireless energy transfer.

What kind of energy could be transferred wirelessly? Obviously, energy stored in chemical bonds within molecules like glucose or methane cannot be transferred without the moving of the material itself; Heat can be transferred wirelessly quite easily, but getting your laptop PC to use heat is not that easy. So we will talk about electric energy, which is being used most widely and easily.

Like wireless information transfer, wireless energy transfer is also based on electromagnetic field. The difference is when you're transferring energy, receive-to-transmit ratio rather than signal-to-noise ratio becomes the most important thing. And usually, the former one is much more difficult to achieve than the latter one over long distances. Based on whether radiative electromagnetic field is generated, the methods of wireless transfer are divided into two categories: near-field and far-field.

Problems of the two-stroke engine

Actually the two-stroke engine should perform twice the performance of a four-stroke engine with the same cubic capacity. Though it is just possible to gain a performance that is about 50% better. The reasons are obvious: The cylinder can't be filled up with the same amount of fuel as in the four-stroke engine, because the individual strokes are seperated not so clearly. If more fuel is induced, it leaves the combustion chamber through the ejection pipe without being burnt. Many concepts were developed to provide a better expulsion of the exhaust in way that the fresh gas doesn't leave the combustion chamber (as for example the "nosepiston" you can see in the animation above, which causes turbulences of a certain type). Though all these inventions, the filling of the two-stroke engine is always worse than in the four-stroke engine, which loses fresh fuel only because of the "overlap" of the valve times (both valves are open for an instant). Beside these performance-technical problems, there are also increasing difficulties with the environment. The fuel mixture of the two-stroke engine often gets shifted with a certain quantity of oil because of the necessary lubrication. Unfortunately the oil gets burnt partly, too, and harmful gases are expulsed by the engine.

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New technology in two stroke engin

Two-stroke engines in motorcycle applications went away for several reasons. First, they had higher levels of hydrocarbon and carbon-monoxide exhaust emissions than four-stroke engines, and reducing those emissions couldn’t readily piggyback on all the work that had been expended by the automotive industry on car engines. Second, they also had worse fuel economy. But, third, and worst of all, they were perceived as “non-green,” smoke-emitting, image disasters. Major companies such as Honda made the decision to stop producing two-strokes, and racing organizations went along by changing rules to penalize or eliminate them. Four-strokes, with a few exceptions, took over off-road motorcycling, even in closed-course competition.

But there was a cost to that. The new four-stroke motocrossers were more expensive and much more maintenance-intensive than the two-stroke machines they replaced. They also tended to have exhaust sound that was offensive for longer distances, putting pressure on motocross tracks in some locations to quiet down or be shut down. And some riders simply liked two-stroke engine characteristics better.

But two other off-road activities also faced the same issues and came up with different solutions. Both the outboard-marine industry and the snowmobile industry initially attempted to make the switch to four-stroke engines but were met with customer resistance to the heavier and more-expensive powerplants that resulted. This opposition led to a new generation of cleaner, direct-injected two-stroke engines that meet respective emissions requirements—though these are notably less strict than those for on-road vehicles. The most recent example would be Ski-Doo’s E-TEC (ecotech) 800cc Rotax Twin, which puts out 155 horsepower—more power per cc than BMW’s S1000RR, the current king of literbike horsepower. Unlike Bimota’s abortive 1997 Vdue, a two-stroke with conventional injectors squirting into the transfer ports—a design that never really worked—the outboard and snowmobile engines are well-developed and reliable.

Now that such technology is available for motorcycle engines, some players in the industry are taking another look, since direct fuel injection has the potential to drastically reduce emissions. Two-stroke engines, which combine the intake and exhaust cycles to a degree not possible in four-strokes, have an issue with fresh charge coming through their transfer ports and flowing directly out the exhaust port, dramatically raising hydrocarbon emissions—and not helping fuel economy, either. Direct injection allows fuel to be injected into the cylinder just as the piston is rising to seal the exhaust port, preventing this direct short-circuiting.

Similarly, conventional two-stroke engines at very low loads may actually be operating on four-, six- or eight-cycle processes. This is because so much exhaust gas is retained in the cylinder at small throttle openings that it may take several crankshaft revolutions to clear the cylinder sufficiently to create a combustible mixture. It’s far better to operate at low loads with intake air only (no fuel lost out the exhaust) and the injection programmed to add fuel only on the combustible cycle. When used with engines designed for them, direct injection systems allow much lower baseline emissions before any after-treatment system (catalytic converter) is added, and they can improve fuel economy by as much as 50 percent.

In addition to direct fuel injection, there are other technologies that can help. Two decades ago, Honda introduced a 250cc, two-stroke motorcycle engine for a Japanese-market-only dual-purpose bike that utilized “Activated Radical Combustion.” This is a technology that has since been well-studied by the automotive industry and is more commonly known as HCCI (Homogenous Charge Compression Ignition), a combustion process that requires no spark but uses gasoline rather than diesel fuel. In Honda’s 250, HCCI combustion was maintained from about eight to 50 percent load, with conventional spark ignition used at both the high and low end of the engine load range. The benefit was far more stable combustion (no six- or eight-cycling) when HCCI was operating, lower emissions and—according to those who rode it—a two-stroke that felt as if it had the smooth power of a four-stroke. Honda’s patents have since expired.

While there is little doubt that technology exists to create off-road two-stroke motorcycle engines that meet current and future EPA or California green-sticker off-road emissions requirements, the question remains whether sufficient technology exists to create street-legal two-stroke engines as in, say, a 300cc dual-purpose bike making 40-plus horsepower. This would require one of the available direct-injection technologies, an oxidizing catalyst in the exhaust and, likely, a direct lubrication system that feeds carefully controlled amounts of oil to the main and rod bearings to minimize oil usage. While that question currently remains unanswered, there is at least one top engine designer at a major manufacturer who believed it was possible five years ago. The technology has only gotten better since.

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Mapping the Dark Cosmos

Dark matter—the unseen stuff that makes up more than four-fifths of the matter in the universe—is finally coming into view. What we see may change our entire picture of reality.

More than 80 percent of the matter in the universe consists of an unknown substance that cannot be seen through any telescope nor detected in any lab. This invisible stuff interacts with normal matter only through gravity, which is how astronomers first inferred its existence. More recently, computer models have demonstrated that dark matter is actually crucial to the visible realm. Without it, galaxies never would have pulled together. There would be no stars. There would be no people.

Although astronomers still do not know exactly what dark matter is, in 2012 they learned a lot more about how it works. One team traced the way it spreads its tentacles throughout the cosmos. And another found hints that dark matter may not always be invisible after all.

Last January, Ludovic van Waerbeke of the University of British Columbia and Catherine Heymans of the University of Edinburgh announced that they had mapped a web of dark matter more than 1 billion light-years across. "That's the largest map ever made of dark matter," Van Waerbeke says. Although the dark stuff cannot be observed directly, its gravity bends light from any galaxies shining through it. Measuring the amount of bending reveals how much dark matter is present.

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Turbocharger

The turbojet employs the same principle as the rocket. It burns oxygen from the atmosphere instead of carrying a supply along.

Notice the similarities: Fuel continuously burns inside a combustion chamber just like the rocket. The expanding gasses escape out the nozzle generating thrust in the opposite direction.
Now the differences: On its way out the nozzle, some of the gas pressure is used to drive a turbine. A turbine is a series of rotors or fans connected to a single shaft. Between each pair of rotors is a stator -- something like a stationary fan. The stators realign the gas flow to most effectively direct it toward the blades of the next rotor.
At the front of the engine, the turbine shaft drives a compressor. The compressor works a lot like the turbine only in reverse. Its purpose is to draw air into the engine and pressurize it.
Turbojet engines are most efficient at high altitudes, where the thin air renders propellers almost useless.