Aug 152016


A new University of California, Davis, study by a top ecological forecaster says it is harder than experts thought to predict when sudden shifts in Earth’s natural systems will occur — a worrisome finding for scientists trying to identify the tipping points that could push climate change into an irreparable global disaster.

“Many scientists are looking for the warning signs that herald sudden changes in natural systems, in hopes of forestalling those changes, or improving our preparations for them,” said UC Davis theoretical ecologist Alan Hastings. “Our new study found, unfortunately, that regime shifts with potentially large consequences can happen without warning — systems can ‘tip’ precipitously.

“This means that some effects of global climate change on ecosystems can be seen only once the effects are dramatic. By that point returning the system to a desirable state will be difficult, if not impossible.”

The current study focuses on models from ecology, but its findings may be applicable to other complex systems, especially ones involving human dynamics such as harvesting of fish stocks or financial markets.

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Originally posted Feb 15, 2010


Jul 272016


These instruments can explore the oceans like sailplanes

The Leibniz Institute of Marine Sciences (IFM-GEOMAR) in Kiel, Germany, recently obtained the biggest fleet of so-called gliders in Europe. These instruments can explore the oceans like sailplanes up to a depth of 1000 metres. In doing so they only consume as much energy as a bike light. In the next years up to ten of these high-tech instruments will take measurements to better understand many processes in the oceans. Currently scientists and technicians prepare the devices for their first mission as a ‘swarm’ in the tropical Atlantic.

They may look like mini-torpedoes, yet exclusively serve peaceful purposes. The payload of the two-metre-long yellow diving robots consists of modern electronics, sensors and high-performance batteries. With these devices the marine scientists can collect selective measurements from the ocean interior while staying ashore themselves. Moreover, the gliders not only transmit the data in real time, but they can be reached by the scientists via satellite telephone and programmed with new mission parameters.

As such the new robots represent an important supplement to previous marine sensor platforms.

“Ten year ago we started to explore the ocean systematically with profiling drifters. Today more than 3000 of these devices constantly provide data from the ocean interior,” explains Professor Torsten Kanzow, oceanographer at IFM-GEOMAR. This highly successful programme has one major disadvantage: the pathways of the drifters cannot be controlled.

“The new gliders have no direct motor, either. But with their small wings they move forward like sailplanes under water,” says Dr. Gerd Krahmann, a colleague of Professor Kanzow. In a zigzag movement, the glider cycles between a maximum depth of 1000 metres and the sea surface.

“By telephone we can ‘talk’ to the glider and upload a new course everytime it comes up,” explains Krahmann. A glider can carry out autonomous missions for weeks or even months. Every glider is equipped with instruments to measure temperature, salinity, oxygen and chlorophyll content as well as the turbidity of the sea water.

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First published in 2010

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Jul 312011

Materials Engineered to Give Off Precisely Tuned Wavelengths of Light When Heated

A new photovoltaic energy-conversion system developed at MIT can be powered solely by heat, generating electricity with no sunlight at all. While the principle involved is not new, a novel way of engineering the surface of a material to convert heat into precisely tuned wavelengths of light — selected to match the wavelengths that photovoltaic cells can best convert to electricity — makes the new system much more efficient than previous versions.

The key to this fine-tuned light emission, described in the journal Physical Review A, lies in a material with billions of nanoscale pits etched on its surface. When the material absorbs heat — whether from the sun, a hydrocarbon fuel, a decaying radioisotope or any other source — the pitted surface radiates energy primarily at these carefully chosen wavelengths.

Based on that technology, MIT researchers have made a button-sized power generator fueled by butane that can run three times longer than a lithium-ion battery of the same weight; the device can then be recharged instantly, just by snapping in a tiny cartridge of fresh fuel. Another device, powered by a radioisotope that steadily produces heat from radioactive decay, could generate electricity for 30 years without refueling or servicing — an ideal source of electricity for spacecraft headed on long missions away from the sun.

According to the U.S. Energy Information Administration, 92 percent of all the energy we use involves converting heat into mechanical energy, and then often into electricity — such as using fuel to boil water to turn a turbine, which is attached to a generator. But today’s mechanical systems have relatively low efficiency, and can’t be scaled down to the small sizes needed for devices such as sensors, smartphones or medical monitors.

“Being able to convert heat from various sources into electricity without moving parts would bring huge benefits,” says Ivan Celanovic ScD ’06, research engineer in MIT’s Institute for Soldier Nanotechnologies (ISN), “especially if we could do it efficiently, relatively inexpensively and on a small scale.”

It has long been known that photovoltaic (PV) cells needn’t always run on sunlight. Half a century ago, researchers developed thermophotovoltaics (TPV), which couple a PV cell with any source of heat: A burning hydrocarbon, for example, heats up a material called the thermal emitter, which radiates heat and light onto the PV diode, generating electricity. The thermal emitter’s radiation includes far more infrared wavelengths than occur in the solar spectrum, and “low band-gap” PV materials invented less than a decade ago can absorb more of that infrared radiation than standard silicon PVs can. But much of the heat is still wasted, so efficiencies remain relatively low.

An ideal match

The solution, Celanovic says, is to design a thermal emitter that radiates only the wavelengths that the PV diode can absorb and convert into electricity, while suppressing other wavelengths. “But how do we find a material that has this magical property of emitting only at the wavelengths that we want?” asks Marin Solja?i?, professor of physics and ISN researcher. The answer: Make a photonic crystal by taking a sample of material and create some nanoscale features on its surface — say, a regularly repeating pattern of holes or ridges — so light propagates through the sample in a dramatically different way.

“By choosing how we design the nanostructure, we can create materials that have novel optical properties,” Solja?i? says. “This gives us the ability to control and manipulate the behavior of light.”

The team — which also includes Peter Bermel, research scientist in the Research Laboratory for Electronics (RLE); Peter Fisher, professor of physics; and Michael Ghebrebrhan, a postdoc in RLE — used a slab of tungsten, engineering billions of tiny pits on its surface. When the slab heats up, it generates bright light with an altered emission spectrum because each pit acts as a resonator, capable of giving off radiation at only certain wavelengths.

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Apr 022011

Envion Oil Generator

The ground-breaking Envion Oil Generator (EOG) gave its first public performance at the Montgomery County Solid Waste Transfer Station in Derwood, Maryland recently.

The EOG can be fed almost any petroleum-based waste plastic and will convert it into synthetic light to medium oil for less than USD$10 per barrel. As with crude oil, the synthetic oil can then be processed into commercial fuels or even back into plastic.

Both a saint and a sinner, plastic has touched almost every part of modern life. It’s everywhere – we live in homes built using it, we eat and drink from it or with it, we drive encased in it, we walk wearing it, we are entertained by it, this article was typed using keys made from it. It has made our lives easier and we have become utterly dependent on it. But it’s this very usefulness – 20 times more plastic is produced today than 50 years ago, some 260 million tons globally – that is behind plastic’s biggest problem. What do you do with it when it’s reached the end of its useful life?

Until relatively recently, our disposable Western mindset would tell us to simply throw the snapped plastic fork or the empty plastic bottle out with the rubbish. Although most of us have now been whipped up into a recycling frenzy, an awful lot of plastic still ends up as waste. In the US it is estimated that less than 4 percent of plastic waste is recycled (2 millions tons, leaving about 46 million tons to be disposed of in other ways).

Whether it’s incinerated (which produces hazardous emissions and toxic ash) or buried in landfill (where various toxic chemicals are released during the slow degradation of plastics) or dumped at sea (that accounts for millions of tons of hazardous floating garbage, such as the Great Pacific Garbage Patch) – humans, animals and the environment suffer as a result.

Energy capture

Given that an awful lot of the plastic we use every day is derived from fossil fuels such as gas and oil and as such contains huge amounts of stored energy which simply goes to waste when it’s thrown away, wouldn’t it be great if we could capture all of this energy and re-use it?

That’s essentially what Envion (a portmanteau of environment and vision) says its EOG does. A reactor converts waste plastic feedstock into oil through low temperature thermal cracking in a vacuum, extracting the hydrocarbons embedded in petroleum-based plastic waste without the use of a catalyst. Roughly around 62 percent of what goes into the unit is successfully converted into oil.

Interestingly, the EOG makes use of some of the by-products of the conversion process to power the unit. Vent gas is recycled to provide electricity and excess oil residue is transformed into emulsified heavy oil.

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Mar 202011
Artist's conception of GPS satellite in orbit
Image via Wikipedia

If you’ve ever owned a recalcitrant retriever, a cat-crazy collie or an overly playful poodle, you’ll know the anxiety of watching them run out of view in search of new adventures, oblivious to your shouts of anguish (and anger). A GPS-enabled collar could be handy for tracking down wayward canines and keep them out of harm’s way … or the clutches of dog-nappers or an over-zealous ranger lurking in the neighborhood. The RoamEO is the latest GPS device for owners who worry about their dogs’ disappearing acts or who are sick of spending valuable time searching for that ‘duck-hunter’ who’s too dog-tired to return with the catch.

While GPS-enabled dog tracking devices aren’t new (Zoombak and Astro) the RoamEO Pup GPS dog collar and handheld LCD display combination is the latest iteration that allows you to see just how far your GPS collar-wearing mutt is from you, as well as the direction they’re traveling and how fast they’re going. It has a maximum range of three miles (approx. 5km), can work indoors and permits tracking of two dogs at once..

Coming soon … PeTnet

Soon to be released is the RoamEO PeTnet which has a couple of additional features, such as being able to track up to three dogs simultaneously and the helpful feature of a virtual fence.

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Mar 142011
Articulation of the mandible. Lateral aspect.

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Technique could be a preferred substitute for replacing missing or damaged bones with titanium, donated bones or those harvested from elsewhere in a patient’s body

Bones often come in complex, delicate shapes, making it hard to find matching natural replacements for them in patients suffering from injuries, diseases or birth defects. Now researchers have grown bone grafts in the exact shape of a desired bone, an advance that could help provide doctors with just what they need for face, skull and other skeletal reconstructions.

Although missing bone can be replaced by titanium, “there is no better substitute for lost tissue than living tissue,” bioengineer Gordana Vunjak-Novakovic at Columbia University explains. “Although titanium is better than nothing—you need something to help bear loads—real bones also have bone marrow inside that has many important metabolic functions.”

Patients also could rely on donated bones, but these run the risk of contamination and tissue rejection. Or surgeons can harvest bone from elsewhere in a patient’s body and carve it to fit where they need to, “but this is very hard on patients,” Vunjak-Novakovic says. “The damage at the site of harvest is major, and it takes long to regenerate this tissue, and patients often report doing so hurts much more and longer than the implant itself.”

Instead, bioengineer Warren Grayson, along with Vunjak-Novakovic and their colleagues, grew their own grafts. They started with the temporomandibular joint, found at the point where the jaw meets the skull in front of the ear. “It was the greatest challenge we could think of, the most complex piece in the skull in terms of shape, based on surgeons we asked,” she says. “If we can grow this piece, we think we can grow anything.”

The temporomandibular joint, or TMJ, is also of growing clinical relevance, Vunjak-Novakovic adds. As many as roughly one out of four people experience symptoms of disorders involving the TMJ, such as pain in the chewing muscles and jaw stiffness as well as painful clicking, popping or grating in the joint.

The researchers first used real bone as a scaffold—”we know actual bones are ideal because they work in real life,” Vunjak-Novakovic says. They stripped the knee joints of calves of all their cells with detergents and enzymes and then, based on digitized x-ray images from an anonymous patient, had machines carve them into cubic-centimeter-size human jaw joints.

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Mar 132011
Quantum dot.

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HOW many inventions does it take to change a light bulb?

More than you might think. Around the world, many people are switching from traditional incandescent bulbs to compact fluorescent (CFL) bulbs, which require less energy to produce a given amount of light, and therefore save money and reduce carbon emissions. But CFLs themselves may soon be overhauled by light emitting diodes (LEDs), which are even more energy efficient and have the further advantage that they come on instantly at full brightness, unlike CFLs, which can take a while to warm up. Advocates of LEDs note that the technology is versatile enough to work in almost any situation, from stadium lighting right down to the tiny light on your phone that flashes to indicate a new message.

But not even LEDs, it seems, are the end of the story. Yet another lighting technology is on the horizon that offers further advantages: even greater power efficiency and softer, warmer light, the colour of which can be precisely controlled. Even though it will be put to rather mundane uses, the technology in question has an exotic name: quantum-dot lighting.

Quantum dots are tiny crystals of semiconducting material just a few tens of atoms, or a few nanometres (billionths of a metre), across. They are typically made using some combination of zinc, cadmium, selenium and sulphur atoms. Their origins go back to work published in 1983 by Louis Brus, then at Bell Labs, in New Jersey, though it was several years before another physicist, Mark Reed at Yale University, described these tiny semiconductor clumps as “quantum dots”. When excited by light or electricity, a quantum dot emits light of a colour determined by the dot’s size and the material from which it is made. Light of a particular colour can therefore be produced by exciting dots of a specific size.

Seth Coe-Sullivan, co-founder and chief technology officer of QD Vision, a start-up spun out of the Massachusetts Institute of Technology, likens a quantum dot to a tuning fork: when it is struck, it oscillates at a specific, fixed frequency, producing a note of a particular pitch (or, in the case of a quantum dot, light of a particular colour). This has immediate applications in general lighting, but quantum dots can also be put to many other uses.

Shine a light

In lighting, quantum dots allow the colour of the light from a light source to be precisely controlled, says Jason Hartlove, the chief executive of Nanosys, based in Palo Alto, California—one of a handful of companies making quantum dots and selling lighting components based on them. The first products to come to market use quantum dots to produce warm, white light from blue LEDs. In essence, quantum dots are used to change the colour of the light. The advantage of this approach is that blue LEDs are the brightest, most energy-efficient kind.

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Mar 122011
Karl Benz's "Velo" model (1894) - en...
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Posh cars already learn how you like your seat and steering wheel adjusted.

The next generation of cars may be smart enough to learn how you drive and warn you when you’re not driving safely.

Drivers go to school to learn to anticipate emerging situations and respond appropriately. Why shouldn’t cars do the same? That’s the question Florentin Wörgötter and his colleagues at the EU-fundedresearch programme DRIVSCO asked themselves three years ago.

Their answer was that, with state-of-the-art sensors, image processors, and learning algorithms, a car that smart could be built.

The result, now tested in a prototype vehicle, is a system that tracks a driver’s every move, matches those actions with what it “sees” down the road, and learns how that driver normally handles situations such as upcoming curves or other vehicles ahead.

With its infrared headlights, stereo cameras, and advanced visual processing the system can actually see better at night than a human driver. It has proved its worth by providing early warnings of hazards a human driver had not yet seen or reacted to.

“What we wanted was a system that learns to drive during the day by correlating what it sees with the actions a driver takes,” says Wörgötter. “Then at night the system could say, ‘Slow down, a curve is coming up!’ — a curve the human didn’t see. Now we have a prototype that does this.”

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Mar 122011

Image by shingo via Flickr

Toshiba has upped the ante in TV technology by unveiling its flagship model, the Cell Regza 55X1. This new 55-inch LED unit has the TV junkie in mind with many features not seen before, including the ability to record up to eight channels at once, a 3TB hard drive (record and store up to 26 hours of HD programs), a powerful processing chip identical to the one found in the PS3, a dynamic contrast ratio of 5,000,000:1, 240Hz scanning, a display divided into 512 distinct areas (each with individually-controlled lighting and luminance that deliver an industry high 1250cd/m2 – 2.5 times higher than typical TVs, and a seven-speaker sound bar. All for a lazy ¥1 million (US$11,500 approx).

And if that doesn’t whet your appetite – wait, there’s more. Toshiba says a self-congruency process improves image quality at the edge of the picture. At the heart of the Regza is the Cell platform, which achieves an arithmetic processing capability approximately 143 times that of current top shelf Regza TV.

The company says its Cell Broadband Engine is specially developed for demanding multimedia applications and, with Toshiba’s advanced image-processing algorithms, the Cell platform achieves these impressive viewing enhancements. This includes improved color and brightness balance for greater picture color and definition, LED backlight control system, luminance to 1250cd/m2, and the dynamic contrast ratio 5,000,000:1.

The Cell microprocessor was developed as a three-way venture among Sony, Toshiba and IBM for reportedly $US400 million. It first appeared in the PS3 but has since been used in IBM servers.

Never miss a moment

Of the 3TB on-board storage, 2TB are set aside for time-shifting – it’s possible to record up to 26 hours (total) of programming simultaneously across eight digital terrestrial broadcasts. A “time shift” key on the remote makes it easy to watch previously recorded programs.

Toshiba believes its improved “roaming navigation” lets viewers easily sort through all the information they may have captured. Searches can be conducted on recorded, current and future programs simply by inserting an identifier — the title, person’s name, genre or related keywords.

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Mar 102011
Computer junk
Image by neofob via Flickr

FOR months, I had been trying to ignore it. Like an ailing relative, my desktop computer was becoming increasingly frail. With each passing day, it took longer and longer to boot up. It sent endless “connecting” messages as I tried to get on the Internet. It froze in confusion if I clicked away too quickly.

My first assumption was that it was time for a new computer. Ours was about five years old, relatively ancient in technological years.

But then I started thinking — should I be so quick to assume that computers and the other gadgets of modern life, like iPods and game systems, are always ready to retire after two years, or three or four? For economic and environmental reasons (repairing is better than replacing), shouldn’t I look into the possibility that we could salvage our computer?

I decided to call Adam Sanderson, chief executive of Computer Overhauls, based in Manhattan. I interviewed Mr. Sanderson about four years ago for a column and have since hired him occasionally for emergency computer problems.

Mr. Sanderson remotely peeked into my computer and confirmed my worst fears — the hard drive was dying.

We could go out and buy a new one. Or, he suggested, we could ship or bring in the tower that contains the hard drive and he would replace it for about $150 — far less than the cheapest desktop we could buy. Prices can be higher for more powerful hard drives and up to about $200 for laptops.

“We would clean out the whole machine, reinstall everything fresh and it would be like a brand-new computer,” he told me.

But then my software wouldn’t be upgraded, would it?

No, Mr. Sanderson told me, but you may not really need to.

“It depends on what you’re using the computer for,” he said. “If you’re surfing the Internet and doing e-mail, which is what the bulk of people do, then you’re only using 5 to 10 percent of the actual power of your computer anyhow. Most people don’t need upgraded software.”

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Mar 092011
Save Planet Earth
Image by ozgurmulazimoglu via Flickr

If efficiency improvements and incremental advances in today’s technologies fail to halt global warming, could revolutionary new carbon-free energy sources save the day? Don’t count on it—but don’t count it out, either

To keep this world tolerable for life as we like it, humanity must complete a marathon of technological change whose finish line lies far over the horizon. Robert H. Socolow and Stephen W. Pacala of Princeton University have compared the feat to a multigenerational relay race. They outline a strategy to win the first 50-year leg by reining back carbon dioxide emissions from a century of unbridled acceleration. Existing technologies, applied both wisely and promptly, should carry us to this first milestone without trampling the global economy. That is a sound plan A.

The plan is far from foolproof, however. It depends on societies ramping up an array of carbon-reducing practices to form seven “wedges,” each of which keeps 25 billion tons of carbon in the ground and out of the air. Any slow starts or early plateaus will pull us off track. And some scientists worry that stabilizing greenhouse gas emissions will require up to 18 wedges by 2056, not the seven that Socolow and Pacala forecast in their most widely cited model.

It is a mistake to assume that carbon releases will rise more slowly than will economic output and energy use, argues Martin I. Hoffert, a physicist at New York University. As oil and gas prices rise, he notes, the energy industry is “recarbonizing” by turning back to coal. “About 850 coal-fired power plants are slated to be built by the U.S., China and India—none of which signed the Kyoto Protocol,” Hoffert says. “By 2012 the emissions of those plants will overwhelm Kyoto reductions by a factor of five.”

Even if plan A works and the teenagers of today complete the first leg of the relay by the time they retire, the race will be but half won. The baton will then pass in 2056 to a new generation for the next and possibly harder part of the marathon: cutting the rate of CO2 emissions in half by 2106.

Sooner or later the world is thus going to need a plan B: one or more fundamentally new technologies that together can supply 10 to 30 terawatts without belching a single ton of carbon dioxide. Energy buffs have been kicking around many such wild ideas since the 1960s. It is time to get serious about them. “If we don’t start now building the infrastructure for a revolutionary change in the energy system,” Hoffert warns, “we’ll never be able to do it in time.”

But what to build? The survey that follows sizes up some of the most promising options, as well as a couple that are popular yet implausible. None of them is a sure thing. But from one of these ideas might emerge a new engine of human civilization.

* Reality factors represent estimated technical feasibility from 1 (implausible) to 5 (ready for market)

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Mar 082011


(Credit: Image courtesy of University of Bath)

Researchers at the University of Bath have used nature for inspiration in designing a new type of swimming robot which could bring a breakthrough in submersible technology.

Conventional submarine robots are powered by propellers that are heavy, inefficient and can get tangled in weeds.

In contrast ‘Gymnobot’, created by researchers from the Ocean Technologies Lab in the University’s Department of Mechanical Engineering, is powered by a fin that runs the length of the underside of its rigid body; this undulates to make a wave in the water which propels the robot forwards.

The design, inspired by the Amazonian knifefish, is thought to be more energy efficient than conventional propellers and allows the robot to navigate shallow water near the sea shore.

Gymnobot could be used to film and study the diverse marine life near the seashore, where conventional submersible robots would have difficulty manoeuvring due to the shallow water with its complex rocky environment and plants that can tangle a propeller.

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Mar 072011
Yellowfin tuna, Thunnus albacares
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How to pillage the oceans deliberately, and by accident

THERE are two ways to overfish the sea. One is to ignore scientific advice and plunder on regardless. The other is to accept the advice, and then discover it isn’t good enough.

For decades the Atlantic bluefin-tuna fishery has fallen into the former camp. The International Commission for the Conservation of Atlantic Tunas (ICCAT), the group charged with managing this fishery, has been a disgrace. Every year, its member states have handed themselves quotas far in excess of those prescribed by the organisation’s scientific advice. Last year things were so bad that ICCAT’s chairman warned members that if they did not do better their power to manage the bluefin would end up being taken away from them. But they failed to restrain themselves, and the backlash has begun. Earlier this year Monaco proposed that the bluefin be listed in Appendix I of CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora). Such a listing would ban all international trade while the stock recovered.

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Mar 062011
Photovoltaic cells produce electricity directl...
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A study in the journal Nature Materials details the creation of a nanowire-based technology that absorbs solar energy at comparable levels to currently available systems while using only 1 percent of the silicon material needed to capture photons.

Imagine a world where sunlight can be captured to produce electricity anywhere, on any surface. The makers of thin-film flexible solar cells imagine that world too. But a big problem has been the amount of silicon needed to harvest a little sunshine.

Now, researchers [led by Harry A. Atwater] at Caltech say they’ve designed a device* that gets comparable solar absorption while using just one percent of the silicon per unit area that current solar cells need. The work was published in the journal Nature Materials.

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Mar 052011


Wouldn’t you love a dollar for every time you heard the phrase “paperless office” being bandied about during the 90s?

Unfortunately, it just didn’t happen, did it? On the contrary – as computer and printer technology continued to evolve and printing emails or web pages became quicker and easier – paper use rapidly increased. These days, the cost of office consumables, particularly toner, ink and copy paper, can be prohibitive. So printer manufacturers are coming up with some very clever ideas to reduce ink and paper costs. We’ve seen portable printers that use zero-ink technology like Dell’s Wasabi printer and the Polaroid portable printer and now there’s PrePeat – an innovative office printer that not only uses no ink or toner, it reuses paper.

The PrePeat uses rewritable plastic sheets made from PET plastic. These sheets can be erased and re-printed about 1000 times per sheet. The heat-sensitive plastic sheets are fed into the printer and a line thermal head either prints a new document in black and white or erases an existing document and reprints another – allowing you to re-use paper again and again.

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