Low-cost, more efficient solar cells mostly plastic
Photomicrograph of a silicon wire array embedded within a transparent, flexible polymer film. Credit: Caltech/Michael Kelzenberg
PORTLAND, Ore. – By growing arrays of silicon wires in a polymer substrate, researchers have demonstrated what they say are flexible solar cells that absorb up to 96 percent of incident light.
California Institute of Technology (Caltech) researchers said the wires are made up of 98 percent plastic, potentially lowering the cost of photovoltaics by using just 1/50th the amount of semiconductor material used today. In tests, the experimental solar cells demonstrated over 90 percent quantum efficiency, compared with 25 percent for the best silicon solar cells.
“By developing light-trapping techniques for relatively sparse wire arrays, not only did we achieve suitable absorption, but we also demonstrated effective optical concentration,” claimed Harry Atwater, director of Caltech’s Resnick Institute.
The silicon wires measure just 1 micron in diameter, but can be as long as 100 microns and can be embedded in a transparent polymer. Light is converted into electricity only inside the wires, but light not immediately absorbed bounces around inside the matrix until it enters another wire. The result, researchers said, is both high concentration and high efficiency in the material.
Solar cells based on the technique could potentially be very inexpensive to manufacture since only 2 percent of the materials are expensive semiconductors while the remainder is made from inexpensive plastic.
According to the filings in Blake J Robbins v Lower Merion School District (PA) et al, the laptops issued to high-school students in the well-heeled Philly suburb have webcams that can be covertly activated by the schools’ administrators, who have used this facility to spy on students and even their families.
The issue came to light when the Robbins’s child was disciplined for “improper behavior in his home” and the Vice Principal used a photo taken by the webcam as evidence. The suit is a class action, brought on behalf of all students issued with these machines.
If true, these allegations are about as creepy as they come. I don’t know about you, but I often have the laptop in the room while I’m getting dressed, having private discussions with my family, and so on. The idea that a school district would not only spy on its students’ clickstreams and emails (bad enough), but also use these machines as AV bugs is purely horrifying.
Schools are in an absolute panic about kids divulging too much online, worried about pedos and marketers and embarrassing photos that will haunt you when you run for office or apply for a job in 10 years. They tell kids to treat their personal details as though they were precious.
But when schools take that personal information, indiscriminately invading privacy (and, of course, punishing students who use proxies and other privacy tools to avoid official surveillance), they send a much more powerful message: your privacy is worthless and you shouldn’t try to protect it.
Robbins v. Lower Merion School District (PDF) (Thanks, Roland!)
Electric Cars: Put A Battery In Your Roof
Lithium-ion batteries used in the current generation of plug-in vehicles depend on dwindling supplies of lithium
PARIS — A nanoscale material developed in Britain could one day yield wafer-thin cellphones and light-weight, long-range electric cars powered by the roof, boot and doors, researchers have reported.
For now, the new technology — a patented mix of carbon fibre and polymer resin that can charge and release electricity just like a regular battery — has not gone beyond a successful laboratory experiment.
But if scaled-up, it could hold several advantages over existing energy sources for hybrid and electric cars, according to the scientists at Imperial College London who developed it.
Lithium-ion batteries used in the current generation of plug-in vehicles are not only heavy, which adds to energy consumption, but also depend on dwindling supplies of the metal lithium, whose prices have risen steadily.
The new material — while expensive to make — is entirely synthetic, which means production would not be limited by availability of natural resources.
Another plus: conventional batteries need chemical reactions to generate juice, a process which causes them to degrade over time and gradually lose the capacity to hold a charge.
The carbon-polymer composite does not depend on chemistry, which not only means a longer life but a quicker charge as well.
Because the material is composed of elements measured in billionths of a metre, “you don’t compromise the mechanical properties of the fibers,” explained Emile Greenhalgh, an engineer at Imperial College and one of the inventors.
As hard a steel, it could in theory double as the body of the vehicle, cutting the weight by up to a third.
The Tesla Roadster, a luxury electric car made in the United States, for example, weighs about 1,200 kilos (2,650 pounds), more than a third of which is accounted for by batteries, which turn the scales at a hefty 450 kilos (990 pounds). The vehicle has a range of about 300 kilometers (185 miles) before a recharge is needed.
“With our material, we would ultimately lose that 450 kilos (990 pounds),” Greenhalgh said in an interview. “That car would be faster and travel further.”
Professor Vladimir Paar
A leading scientist has revealed that Europe could be just five years away from the start of a new Ice Age.
While climate change campaigners say global warming is the planet’s biggest danger, renowned physicist Vladimir Paar says most of central Europe will soon be covered in ice.
The freeze will be so complete that people will be able to walk from England to Ireland or across the North Sea from Scotland to northern Europe.
Professor Paar, from Croatia’s Zagreb University, has spent decades analysing previous ice ages in Europe and what caused them.
“Most of Europe will be under ice, including Germany, Poland, France, Austria, Slovakia and a part of Slovenia,” said the professor in an interview with the Index.hr.
“Previous ice ages lasted about 70,000 years. That’s a fact and the new ice age can’t be avoided.
“The big question is what will happen to the people of the Central European countries which will be under ice?
“They might migrate to the south, or might stay, but with a huge increase in energy use,” he warned.
“This could happen in five, 10, 50 or 100 years, or even later. We can’t predict it precisely, but it will come,” he added.
And the professor said that scientists think global warming is simply a natural part of the planet.
“What I mean is that global warming is natural. Some 130,000 years ago the earth’s temperature was the same as now, the level of CO2 was almost the same and the level of the sea was four metres higher.
“They keep warning people about global warming, but half of America no longer believes it as they keep freezing,” he said.
And he added: “The reality is that mankind needs to start preparing for the ice age. We are at the end of the global warming period. The ice age is to follow. The global warming period should have ended a few thousands of years ago, we should have already been in the ice age. Therefore we do not know precisely when it could start – but soon.”
Police forces all over the UK will soon be able to draw on unmanned aircraft from a national fleet, according to Home Office plans. Last month it was revealed that modified military aircraft drones will carry out surveillance on everyone from protesters and antisocial motorists to fly-tippers, and will be in place in time for the 2012 Olympics.
Surveillance is only the start, however. Military drones quickly moved from reconnaissance to strike, and if the British police follow suit, their drones could be armed — but with non-lethal weapons rather than Hellfire missiles.
The flying robot fleet will range from miniature tactical craft such as the miniature AirRobot being tested by Essex police, to BAE System’s new HERTI drone as flown in Afghanistan. The drones are cheaper than police helicopters — some of which will be retired — and are as wide as 12m in the case of HERTI.
Watching events on the ground without being able to act is frustrating. Targets often got away before an unarmed drone could summon assistance. In fact, in 2000 it was reported that an airborne drone spotted Osama bin Laden but could do nothing but watch him escape. So the RAF has been carrying out missions in Afghanistan with missile-armed Reapers since 2007. From the ground these just look like regular aircraft.
The police have already had a similar experience with CCTV. As well as observing, some of these are now equipped with speakers. Pioneered in Middleborough, the talking CCTV allows an operator to tell off anyone engaging in vandalism, graffiti or littering.
Unmanned aircraft can also be fitted with speakers, such as the Long Range Acoustic Device (LRAD), which could not only warn fly tippers that they were breaking the law but also be loud enough to drive them away.
The LRAD is a highly directional speaker made of a flat array of piezoelectric transducers, producing intense beam of sound in a 30-degree cone. It can be used as a loudhailer, or deafen the target with a jarring, discordant noise. Some ships now carry LRAD as an anti-pirate measure: It was used to drive off an attack on the Seabourn Spirit off Somalia in 2005.
LRAD makers American Technology prefer to call its product a device rather than a weapon, and use terms such as “deterrent tones” and “influencing behaviour.” Police in the US have already adopted a vehicle-mounted LRAD for crowd control, breaking up protests at the G20 summit in Pittsburgh last year, although there have been warnings about the risk of hearing damage.
The LRAD has been tested on the Austrian S-100 unmanned helicopter, and the technology is ready if there is a police requirement.
But rather than just driving them away, a police drone should be able to stop fleeing criminals in their tracks. Helicopters already mount powerful searchlights, and strobe lighting capabilities can turn such systems into effective nonlethal weapons. High-intensity strobes can cause dizziness, disorientation and loss of balance making it virtually impossible to run away.
This effect was first harnessed in the “Photic Driver” made by British company Allen International in 1973. However, it has taken improvement in lighting technology (such as fast-switching Xenon lights) and an understanding of the physiology involved to make such weapons practical.
A “light based personnel immobilisation device” developed by Peak Beam Systems Inc has been successfully tested by the US military, and work to mount it on an unmanned helicopter in the States is under way.
This sort of light would be too dangerous for a manned aircraft because of the crew being affected. But an unmanned “strober” could be a literal crime stopper, and something we could see deployed within the next couple of years.
Even the smallest drones could be used for tactical police operations. As far back as 1972 the Home Office looked at model aircraft as an alternative to rubber bullets, literally flying them into rioters to knock them off their feet.
French company Tecknisolar Seni has demonstrated a portable drone armed with a double-barrelled 44mm Flash-Ball gun. Used by French special police units, the one-kilo Flash-Ball resembles a large calibre handgun and fires non-lethal rounds, including tear gas and rubber impact rounds to bring down a suspect without permanent damage — “the same effect as the punch of a champion boxer,” claim makers Verney-Carron.
However, last year there were questions over the use of Flash-Ball rounds by French police. Like other impact rounds, the Flash-Ball is meant to be aimed at the body — firing from a remote, flying platform is likely to increase the risk of head injury.
Another option is the taser. Taser stun guns are now so light (about 150 grams) that they could be mounted on the smaller drones. Antoine di Zazzo, head of SMP Technologies, which distributes tasers in France, says the company is fitting one to a small quad-rotor iDrone (another quad-rotor toy helicopter), which some have called a “flying saucer”.
WARSAW (Reuters) – A Polish priest has installed an electronic reader in his church for schoolchildren to leave their fingerprints in order to monitor their attendance at mass, the Gazeta Wyborcza daily said on Friday.
The pupils will mark their fingerprints every time they go to church over three years and if they attend 200 masses they will be freed from the obligation of having to pass an exam prior to their confirmation, the paper said.
The pupils in the southern town of Gryfow Slaski told the daily they liked the idea and also the priest, Grzegorz Sowa, who invented it.
“This is comfortable. We don’t have to stand in a line to get the priest’s signature (confirming our presence at the mass) in our confirmation notebooks,” said one pupil, who gave her name as Karolina.
At today’s press conference at The Washington Auto Show, Department of Energy Secretary Steven Chu had something to say about electric vehicles, and how the U.S. government would approach aiding EV manufacturers. Although it was originally thought that announcement would concern the loans that Tesla, Fisker et al have received, the surprise announcement concerned Nissan’s Leaf all electric car.
The Leaf, which Nissan says should get 100 miles to a charge, cost around $25,000 to $30,000 and should be in showrooms soon, will be receiving $1.4 billion from the American government to upgrade the company’s manufacturing plant located in Smyrna, Tennessee.
At the D.C. Auto Show Secretary of Energy Steven Chu announced that the Department of Energy had closed a $1.4 billion loan agreement with Nissan to support the modification of the company’s Smyrna, Tennessee, manufacturing plant to produce both the Nissan LEAF as well as the lithium-ion battery packs that will power them.
The $1.4 billion is part of the Advanced Technology Vehicles Manufacturing Loan Program, a $25 billion program that was authorized by Congress in 2007, according to Clean Skies. The Japanese automaker says the loan will allow them to generate up to 1,300 jobs when the Tennessee plants are working at full volume. The factory modifications will begin later in 2010 and include the new battery plant as well as changes to the existing structure for electric-vehicle assembly.
Eventually the plants will construct up to 150,000 Nissan LEAF electric cars a year and as many as 200,000 batteries.
|The warning applies to versions 6, 7 and 8 of Internet Explorer|
The German government has warned web users to find an alternative browser to Internet Explorer to protect security.
The warning from the Federal Office for Information Security comes after Microsoft admitted IE was the weak link in recent attacks on Google’s systems.
Microsoft rejected the warning, saying that the risk to users was low and that the browsers’ increased security setting would prevent any serious risk.
However, German authorities say that even this would not make IE fully safe.
Thomas Baumgaertner, a spokesman for Microsoft in Germany, said that while they were aware of the warning, they did not agree with it, saying that the attacks on Google were by “highly motivated people with a very specific agenda”.
“These were not attacks against general users or consumers,” said Mr Baumgaertner.
“There is no threat to the general user, consequently we do not support this warning,” he added.
“Mobile Protector,” allows a parent to screen a child’s incoming and outgoing calls and messages
LAS VEGAS, Nevada — Stun gun maker Taser wants to help parents, not with jolts of electricity but with a tool which allows parents to effectively take over a child’s mobile phone and manage its use.
“Basically we’re taking old fashioned parenting and bringing it into the mobile world,” Taser chairman and co-founder Tom Smith said at the Consumer Electronics Show here, where the Arizona company unveiled the new product.
“Because when you give your child his mobile phone you don’t know who they’re talking to, what they’re sending or texting, all of those things,” Smith told AFP.
The phone application, called “Mobile Protector,” allows a parent to screen a child’s incoming and outgoing calls and messages, block particular numbers and even listen in on a conversation.