Molybdenum Di-Sulphide (MoS2): A potential challenger to graphene

Sheets of tin sulphide - The diameter of the roll is about 10 times smaller than a human hair.

A team of researchers from the University of Southampton's Optoelectronics Research Centre (ORC) has developed a new way to fabricate a potential challenger to Manchester's Graphene.

Graphene, a single layer of carbon atoms in a honeycomb lattice, is increasingly being used in new electronic and mechanical applications, such as transistors, switches and light sources, thanks to the unprecedented properties it offers: very low electrical resistance, high thermal conductivity and mechanically stretchable yet harder than diamond.

Molybdenum Di-Sulphide (MoS2)

Now, ORC researchers have developed Molybdenum Di-Sulphide (MoS2), a similar material to graphene that shares many of its properties, including extraordinary electronic conduction and mechanical strength, but made from a metal (in this case molybdenum combined with sulphur).

This new class of thin metal/sulphide materials, known as transition metal di-chalcogenides (TMDCs), has become an exciting complimentary material to graphene.

However, unlike graphene, TMDCs can also emit light allowing applications, such as photodetectors and light emitting devices, to be manufactured.

Until recently, fabrication of TMDCs, such as MoS2, has been difficult, as most techniques produce only flakes, typically just a few hundred square microns in area.

Dr Kevin Huang, from ORC who has led the research, explains: "We have been working on the synthesis of chalcogenide materials using a chemical vapour deposition (CVD) process since 2001 and our technology has now achieved the fabrication of large area (>1000 mm2) ultra- thin films only a few atoms thick."

"Being able to manufacture sheets of MoS2 and related materials, rather than just microscopic flakes, as previously was the case, greatly expands their promise for nanoelectronic and optoelectronic applications."

Dr Huang and his team published their findings in the latest issue of the journal Nanoscale.

They are currently working with several UK companies and universities, as well as leading international centres at MIT and Nanyang Technological University (Singapore).

Dr Huang adds: "Our ability to not only synthesise large uniform thin films but also to transfer these films to virtually any substrate has led to increased demand for our materials."

More Information
"Scalable high-mobility MoS2 thin films fabricated by an atmospheric pressure chemical vapor deposition process at ambient temperature" Author: Chung-Che Huang, Feras Al-Saab, Yudong Wang, Jun-Yu Ou, John C. Walker, Shuncai Wang, Behrad Gholipour, Robert E. Simpsond and    Daniel W. Hewaka - Nanoscale, 2014, Advance Article DOI: 10.1039/C4NR04228J - Received 25 Jul 2014

Astronomers detect Light from Gamma Ray Burst from huge explosion 12 billion years ago

Light from the explosion 12 billion years ago of a massive star at the end of its life reached Earth recently. 

An image of its peak afterglow, circled with blue and yellow, was captured by Southern Methodist University's ROTSE-IIIb telescope at McDonald Observatory, Fort Davis, Texas. 

A bright star sits alongside the afterglow from GRB 140419A. 

Credit: ROTSE-IIIb, SMU

Known as a gamma-ray burst, the intense light captured in the night sky resulted from one of the biggest and hottest explosions in the universe, occurring shortly after the Big Bang.

Intense light from the enormous explosion of a star more than 12 billion years ago, shortly after the Big Bang, recently reached Earth and was visible in the sky.

Known as a gamma-ray burst, light from the rare, high-energy explosion traveled for 12.1 billion years before it was detected and observed by a telescope owned by Southern Methodist University, Dallas.


Gamma-ray bursts (GRBs) are believed to be the catastrophic collapse of a star at the end of its life. SMU physicists report that their telescope was the first on the ground to observe the burst and to capture an image, said Farley Ferrante, a graduate student in SMU's Department of Physics, who monitored the observations along with two astronomers in Turkey and Hawaii.

Recorded as GRB 140419A by NASA's Gamma-ray Coordinates Network, the burst was spotted at 11 p.m. April 19 by SMU's robotic telescope, ROTSE-IIIb, at the McDonald Observatory in the Davis Mountains of West Texas.

Gamma-ray bursts (GRBs) are not well understood by astronomers, but they are considered important, Ferrante said.

"As NASA points out, gamma-ray bursts are the most powerful explosions in the universe since the Big Bang," he said. "These bursts release more energy in 10 seconds than our Earth's sun during its entire expected lifespan of 10 billion years."

Some of these gamma-ray bursts appear to be related to supernovae, and correspond to the end-of-life of a massive star, said Robert Kehoe, physics professor and leader of the SMU astronomy team.

"Gamma-ray bursts (GRBs) may be particularly massive cousins to supernovae, or may correspond to cases in which the explosion ejecta are more beamed in our direction. By studying them, we learn about supernovae," Kehoe said.

Scientists weren't able to detect optical light from gamma-ray bursts until the late 1990s, when telescope technology improved.

Among all lights in the electromagnetic spectrum, gamma rays have the shortest wavelengths and are visible only using special detectors.

SMU's ROTSE-IIIb at the McDonald Observatory, Fort Davis, Texas had the earliest and brightest observation from the ground of a gamma-ray burst that occurred more than 12 billion years ago. 

The telescope is part of the Robotic Optical Transient Search Experiment, which has telescopes in four locations on Earth to cover the entire sky in search of gamma-ray bursts. 

Credit: ROTSE Collaboration.

Gamma-ray bursts (GRBs) result from hot stars that measure as enormous as 50 solar masses. The explosion occurs when the stars run out of fuel and collapse in on themselves, forming black holes.

Outer layers detonate, shooting out material along the rotation axis in powerful, high-energy jets that include gamma radiation.

As the gamma radiation declines, the explosion produces an afterglow of visible optical light. The light, in turn, fades very quickly, said Kehoe.

Physicists calculate the distance of the explosion based on the shifting wavelength of the light, or redshift.

"The optical light is visible for anywhere from a few seconds to a few hours," Kehoe said. "Sometimes optical telescopes can capture the spectra."

"This allows us to calculate the redshift of the light, which tells us how fast the light is moving away from us. This is an indirect indication of the distance from us."

ESA Herschel: Shining a light on cool pools of gas in the galaxy

This illustration shows a newfound reservoir of stellar fuel discovered by the Herschel space observatory (red). 

Credit: ESA/NASA/JPL-Caltech

Newly formed stars shine brightly, practically crying out, "Hey, look at me!" But not everything in our Milky Way galaxy is easy to see.

The bulk of material between the stars in the galaxy -- the cool hydrogen gas from which stars spring -- is nearly impossible to find.

A new study from the Hershel Space Observatory, a European Space Agency mission with important NASA participation, is shining a light on these hidden pools of gas, revealing their whereabouts and quantities.

In the same way that dyes are used to visualize swirling motions of transparent fluids, the Herschel team has used a new tracer to map the invisible hydrogen gas.

The discovery reveals that the reservoir of raw material for making stars had been underestimated before -- almost by one third -- and extends farther out from our galaxy's center than known before.

Jorge Pineda

"There is an enormous additional reservoir of material available to form new stars that we couldn't identify before," said Jorge Pineda of NASA's Jet Propulsion Laboratory, Pasadena, Calif., lead author of a new paper on the findings published in the journal Astronomy and Astrophysics.

"We had to go to space to solve this mystery because our atmosphere absorbs the specific radiation we wanted to detect," said William Langer of JPL, principal investigator of the Herschel project to map the gas.

"We also needed to see far-infrared light to pinpoint the location of the gas. For both these reasons, Herschel was the only telescope for the job."

Stars are created from clouds of gas, made of hydrogen molecules. The first step in making a star is to squeeze gas together enough that atoms fuse into molecules.

William Langer

The gas starts out sparse but, through the pull of gravity and sometimes other constricting forces, it collects and becomes denser.

When the hydrogen gets dense enough, nuclear fusion takes place and a star is born, shining with starlight.

Astronomers studying stars want to follow this journey, from a star's humble beginnings as a cloud of molecules to a full-blown blazing orb.

To do so requires mapping the distribution of the stellar hydrogen fuel across the galaxy.

Unfortunately, most hydrogen molecules in space are too cold to give off any visible light. They lurk unseen by most telescopes.

For decades, researchers have turned to a tracer molecule called carbon monoxide, which goes hand-in-hand with the hydrogen molecules, revealing their location, but this method has limitations.

In regions where the gas is just beginning to pool -- the earliest stage of cloud formation -- there is no carbon monoxide.

"Ultraviolet light destroys the carbon monoxide," said Langer. "In the space between stars, where the gas is very thin, there is not enough dust to shield molecules from destruction by ultraviolet light."

A different tracer -- ionized carbon -- does, however, linger in these large but relatively empty spaces, and can be used to pin down the hydrogen molecules.

Researchers have observed ionized carbon from space before, but Herschel has, for the first time, provided a dramatically improved geographic map of its location and abundance in the galaxy.

"Thanks to Herschel's incredible sensitivity, we can separate material moving at different speeds," said Paul Goldsmith, a co-author and the NASA Herschel Project Scientist at JPL. "We finally can get the whole picture of what's available to make future generations of stars."

Read a more in-depth story about this research from the European Space Agency at http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=51909 .

The technical paper is online at http://arxiv.org/abs/1304.7770

Metascreen: Metamaterial research into light transparency

Researchers have now developed a cloak that is just micrometers thick and can hide three-dimensional objects from microwaves in their natural environment, in all directions and from all of the observers’ positions. 

Credit: Image courtesy of Institute of Physics

Their research, which has so far produced an ultralow profile cloak designed for "scattering suppression of a finite-length rod in free space", has been published in the New Journal of Physics.

Presenting their study today, 26 March, in the Institute of Physics and German Physical Society's New Journal of Physics, the researchers, from the University of Texas at Austin, have used a new, ultra-thin layer called a "metascreen."

The cloak is made of a new kind of material called a metascreen, made up of strips of copper tape attached to a flexible polycarbonate film.

Andrea Alu

The copper strips are only 66 micrometres thick and the polycarbonate film is 100 micrometres thick, and the two combined make a diagonal fishnet pattern.

It works by scattering and cancelling out incoming waves, and the researchers were able to use the cloak to shield an 18 centimetre-tall cylindrical rod from microwaves.

"When the scattered fields from the cloak and the object interfere, they cancel each other out and the overall effect is transparency and invisibility at all angles of observation," said Andrea Alu, one of the physicists.

Journal Reference: 
J C Soric, P Y Chen, A Kerkhoff, D Rainwater, K Melin, A Al. Demonstration of an ultralow profile cloak for scattering suppression of a finite-length rod in free space. New Journal of Physics, 2013; 15 (3): 033037 DOI: 10.1088/1367-2630/15/3/033037

French Scientists: 'Background' light of universe measured

The brightness of the background of light photons that has filled the universe since its formation has been measured for the first time, French researchers say.

Scientists at the country's National Center for Scientific Research say their findings could provide new insight into the size of the universe, the formation of stars and the evolution of galaxies.

Download the CNRS Press Release here

The light emitted by all the objects in the universe, such as stars and galaxies, ever since its birth fills intergalactic space with an "ocean" of photons known as the "diffuse extragalactic background light," the researchers said.

The shine of our own galaxy makes it impossible to directly measure this fossil record of the light emitted in the universe, so astrophysicists made use of gamma rays, with energy more than 500 billion times greater than that of visible light, as an alternative, indirect method of measuring this light, a release from the center said.

These measurements made it possible to estimate for the first time the intensity of the starlight contained within all the universe at wavelengths ranging from the near infrared to the ultraviolet, including visible wavelengths, it said.

A better understanding of this diffuse light should yield information about the first stars, shedding light on their formation and on the evolution of galaxies, astronomers said.

Aberdeen Scientists Find Link Between Light Deficiency and Multiple Sclerosis

Aberdeen scientists have found that artificial sunlight can have a “striking effect” in helping treat sufferers of diseases such as multiple sclerosis.

Researchers from Aberdeen University studied patients in the north of Scotland – which has the highest rate of MS in the UK - who were being treated during winter with artificial UV (ultraviolet)-B light therapy for skin diseases caused by their immune systems acting inappropriately.

The research - published in the Journal of Allergy and Clinical Immunology – shows how UV-B light boosts vitamin D, as well as cells in our body that are responsible for regulating or balancing the immune system. Vitamin D is made in our bodies by UV-B light from the sun.

Some studies have suggested a link between vitamin D deficiency and autoimmune diseases such as MS.

This possible link might also explain the increasing prevalence of autoimmune disease among those living far from the equator, where there are lower levels of winter sun.

Autoimmune diseases - like MS and type 1 diabetes - are diseases where the immune system mistakenly attacks the body’s own tissues or harmless substances that enter the body.

Dr Anthony Ormerod, clinical reader in dermatology at the university, said: “Our study shows that UV-B light, which mimics sunshine, can have a striking effect on the immune system of patients.

“We found that UV-B light boosted the production of vitamin D, and of regulatory T cells, which play an important role keeping our immune systems in check.

“Our findings have important implications for future interventions including the recommendations for healthy lifestyle and a possible role for phototherapy and/or vitamin D supplementation in the prevention or treatment of autoimmune and inflammatory diseases.

“While too much exposure to sunlight is harmful and increases skin cancer risk, these results suggest that subjects in our study would have some benefits from small amounts equivalent to summer exposure in the winter but more work needs to determine the role of sunlight and the role of supplementing the diet with vitamin D.”

Dr Helen Macdonald, senior lecturer in nutrition and translational musculoskeletal research at the university and chair of the National Osteoporosis Society Nutrition and Lifestyle forum, said: “There are risks associated with high levels of both therapies, so it is important that we get the balance right.

“We would also want to stress that we are not advocating sun bed use since this is not the same type of radiation produced by sun beds which already have well-documented health risks.

“The average dose of UV light that the volunteers received was the equivalent to sunlight exposure in Aberdeen over spring and summer and further work is required to determine if lower doses are effective.”

Professor Mark Vickers, chair in applied medicine at the university, added: “Ours is the first study to demonstrate in patients a cause and effect between UV light, vitamin D and systemic immune function in people.”

STFC: SCUBA-2 reveals wild youth of the Universe

A team of astronomers from the UK, Canada and the Netherlands has begun a revolutionary new study of cosmic star-formation history, looking back in time to when the Universe was still in its lively and somewhat unruly youth.

The consortium, co-led by University of Edinburgh astrophysicist Professor James Dunlop, is using SCUBA-2, the most powerful camera ever developed for observing light at ‘sub-mm’ wavelengths (light that has a wavelength 1000 times longer than we can see with our eyes).

Prof. Dunlop presented the first results from the survey at the UK National Astronomy Meeting on 27 March 2012.

The development of SCUBA-2 was led by STFC’s UK Astronomy Technology Centre in Edinburgh and the revolutionary camera was unveiled in December 2011 (link opens in a new window).

It is mounted on the world's largest sub-mm telescope, the 15-metre James Clerk Maxwell Telescope in Hawaii.

The new project, named the SCUBA-2 Cosmology Legacy Survey, will run for three years and will use the camera to provide the clearest view to date of dust-enshrouded star-forming galaxies.

These objects are so remote that the light we detect left them billions of years ago, so we see them as they looked in the distant past.

With SCUBA-2 astronomers are able to study objects that existed as far back as 13 billion years ago, within the first billion years after the Big Bang.

Because stars form inside clouds of gas and dust, much of the ultraviolet light from young galaxies is absorbed by this cosmic dust which is then heated to a few tens of degrees above absolute zero (-273 degrees Celsius).

The ‘warmed’ (but still rather ‘cool’) dust then emits the absorbed energy at far-infrared wavelengths, which is then further redshifted to longer sub-mm wavelengths en-route to the Earth by the expansion of the Universe.

The first image presented here is made using the SCUBA-2 camera at a wavelength of 450 microns.
(Credit: Jim Dunlop)

Detecting such emission is a challenge, both because Earth-based telescopes are warm and hence glow at sub-mm wavelengths and because water vapour in the atmosphere both absorbs and emits light in this waveband.

To get around the problems of the atmosphere, the latest sub-mm surveys have recently been conducted from space, using the Herschel Space Observatory.

However, the relatively small size (3.5-metre diameter) of Herschel’s telescope means that the images it produces cover large areas but are rather fuzzy.

The James Clerk Maxwell Telescope primary mirror is 20 times larger in area and can provide a much sharper view of the sub-mm sky.

Prof. Dunlop is delighted by these first deep SCUBA-2 images and looking forward to more results over the next few years: “Edinburgh scientists and engineers worked hard to construct this revolutionary new instrument and, together with our colleagues in Canada and the Netherlands, we’re now seeing the fruits of our efforts.

With SCUBA-2 we can study the most violently star-forming galaxies in the young Universe, and slowly but surely start to understand how the primitive cosmos evolved into the Universe we live in today.”

Personalised Tron Lightcycle up for auction

If you are impressed with the All-Electric Lightcycle, you now have the chance to get one in their garage, and help the environment.

The opportunity comes courtesy of Charitybuzz, which is auctioning off a replica Lightcycle, otherwise known as a Xenon Light Motor Bike.

The vehicle on offer was designed by Parker Brother Choppers and donated by Evolve Motorcycles, which created a custom lithium ion battery system to power the bike's electric motor. The bike features a handcrafted fiberglass frame and 32-inch hub-less wheels offset by OLED light tape.

Although the auction listing cites a range of 100 miles and a top speed of 50 mph (80 km/h) for the bike, it also says the winning bidder will be able to choose the bike's battery and motor type.

The personalization options will also extend to the bike's light tape colour.

Evolve sells the bike for US$55,000 and as of publication the bidding stands at $24,000, so you might just be able to nab a bargain. The auction closes on March 14, 2012 with all proceeds benefiting Global Green USA.

Source: Charitybuzz

NPL to make reflected light measurements

A researcher from NIST (National Institute of Standards and Technology), the national measurement institute of the USA, recently visited the UK to utilise NPL's world-leading facilities for measuring the optical properties of materials, and specifically for measuring reflectance of samples in the infrared.

Out of all the measurement institutes around the world, NPL is capable of making these measurements over the widest range of infrared wavelengths.

In the USA, NIST is developing a fibre-coupled cryogenic radiometer that links optical fibre power measurements directly to fundamental electrical units at the 10 nW power level.

Such a device could have a role in telecommunications, medical devices and other industries that require ultra low power calibrations.

Cryogenic radiometry was first developed at NPL. It works by absorbing optical power which causes a temperature rise in the absorber.

The amount of electrical power needed to induce the same temperature rise is then measured. To make the most accurate measurements, the device needs to employ a surface that absorbs the largest amount of optical energy possible, and reflects the least.

A coating of carbon nanotubes, arranged so that they stand vertically on the surface like a forest of trees, provide this surface.

The arrangement forms the lowest reflective, or darkest, surface known to man and only NPL's facilities are capable of making the required measurements of reflected infrared light to test it.

Two facilities were used at NPL: the first, based on a grating spectrometer and integrating sphere, covers the range of the electromagnetic spectrum from visible light to a wavelength of 2.5 µm; and the second facility uses a Fourier transform spectrometer and reflecting hemisphere to cover the range from 2.5 µm to 50 µm.

The measurements made during this project represent the first ever reflectance measurements of materials with reflectance less than 1% in the 15–50 µm region and confirm that the NIST carbon nanotube coatings have the lowest known reflectance in the infrared region.

NPL and NIST have collaborated since 2003 to assess the benefits to the performance of thermal detectors obtained by using carbon nanotube coatings, and half a dozen papers have been jointly authored reporting those findings.

The current work has expanded NPL's collaboration with NIST and is described in a paper submitted for publication in a peer-reviewed journal.

More on NPL's work on Optical Radiation and Photonics

More on NPL's work on Reflected Light

For further information, please contact Christopher Chunnilall or Theo Theocharous

Artificial Lightings Seen in Kuiper Belt: Alien World?

ET watchers may be able to find an alien world through telescopes that may spot artificial lightings "out there."

A new study points to the possibility of finding extraterrestrial civilizations that may have also developed artificial lighting sources which our next generation telescopes can detect.

Researchers Abraham Loeb from Harvard and Edwin L. Turner of Princeton, said it is possible to peer into space and spot artificially illuminated objects, adding that current optical telescopes and surveys have the ability to see this amount of light at the edge of our Solar System and observations with large telescopes can measure a Kuiper Belt Objects spectra to determine if they are illuminated by artificial lighting.

Distinguishing an artificial illumination from solar illumination on KBO with typical albedo may be tricky, but the researchers said the existing telescopes and surveys can spot the difference as it will carry the dead give-away which is the spectral signature.

According to Loeb and Turner, our civilization uses two basic classes of illumination, thermal (incandescent light bulbs) and quantum (light emitting diodes and fluorescent lamps). "Such artificial light sources have different spectral properties than sunlight.

The spectra of artificial lights on distant objects would likely distinguish them from natural illumination sources, since such emission would be exceptionally rare in the natural thermodynamic conditions present on the surface of relatively cold objects.

Therefore, artificial illumination may serve as a lamppost which signals the existence of extraterrestrial technologies and thus civilizations," the researchers said.

Not all random light source detected where there should be darkness might be considered a sign of life, the study said, as there are many factors which could contribute to illumination, such as viewing angle, backscattering, surface shadowing, outgassing, rotation, surface albedo variations and more.

A Star is Born: Dark-Hued Nebula

The region lies near the southern end of Taurus located on the border of the constellations of Taurus and Perseus more than 400 light-years away. 

A light-year is the distance light travels in one year, or about 6 trillion miles (10 trillion kilometers).

CREDIT: Adam Block/Mount Lemmon SkyCenter/University of Arizona

This photo shows the cosmic region known as Sh2-239 and LDN 155, where star formation activity has caused the mix of dust and colors in the nebulas visible here.

The deep colours and dark clouds in this image resemble paintings by some of history's greatest artists.

Astrophotographer Adam Block of the Mt. Lemmon SkyCenter at the University of Arizona was one of the first to capture the nebula in such detail.

He took multiple exposures to collect enough light for an image that would otherwise not be evident to the eye.

"Sh2-239 is my favourite object, because although it is a well-studied nebula, not even professional astronomers have seen it in such detail and in the visible light." Block wrote in an email.

The region lies near the southern end of the constellation Taurus, near the border of the constellation Perseus, more than 400 light-years away.

A light-year is the distance light travels in one year, or about 6 trillion miles (10 trillion kilometers).

The region is often photographed by skywatchers and consists of bright red emission nebulas, star clusters, complex dark nebulas and blue reflected light. The spot is known as a birthplace for stars.

A star develops from a giant, slowly rotating cloud that is made up almost entirely of hydrogen and helium. The process creates new stars and releases cosmic dust and gas.

Visualising Light at Trillion Frames per Second - MIT

 

View more on this video at MIT Portal

Second Experiment Confirms Faster-Than-Light Neutrinos - Einstein's Theory questioned

A new experiment appears to provide further evidence that neutrinos can travel faster than light, contradicting Einstein's theory of relativity that underpins modern thinking of how the universe works.

Albert Einstein published his theory of relativity in 1905 and asserted that nothing - no matter how small - can travel faster than the speed of light, which is approximately 186,000 miles per second.

The experiment, which is the second of its kind this year, took place at the Gran Sasso laboratory in Italy and used a neutrino beam from CERN in Switzerland 450 miles away.

Scientists at the Italian Institute for Nuclear Physics (INFN) said in a statement that their new tests aimed to exclude one potential systematic effect that might have affected the original measurement.

"A measurement so delicate and carrying a profound implication on physics requires an extraordinary level of scrutiny," said Fernando Ferroni, president of the INFN.

Scientists were shocked in September when a similar experiment found that neutrinos had travelled faster than light and - in theory - arrived at their destination before they set off.

Reuters reports that physicists involved said they had checked and rechecked anything that could have produced a misreading before announcing what they had found.

In an attempt to rule out any margin for error, the beams sent by CERN in this latest experiment were a few nanoseconds shorter than those sent in the September experiment, with larger gaps of 524 nanoseconds between them, resulting in more accurate timing.

"In this way, compared to the previous measurement, the neutrinos bunches are narrower and more spaced from each other," the scientists said. "This permits to make a more accurate measure of their velocity at the price of a much lower beam intensity."

Although errors can still not be completely ruled out, this evidence does further suggest that Einstein's theory of relativity was incorrect, forcing a major rethinking about how the cosmos works. It may even mean that sending information back in time could be made possible.

SAD: Take your light therapy, and stick it in your ear

Many readers in the Northern Hemisphere are likely already starting to experience seasonal affective disorder, appropriately enough known as SAD.

For those people fortunate enough not to be familiar with it, SAD is a mood disorder that is brought on by the shorter day-length experienced in winter - less sunlight results in gloomier people.

One of the most common treatments involves regular exposure to bright artificial lights, that appear to psychologically serve the same purpose as sunlight.

Now, one might assume that such light therapy would require that people see the light. According to the Finnish designers of the Valkee device, however, light also does the trick if you shine it up your ears.

The invention is based around the assertion that not only are our visual systems photosensitive, but so are our brains themselves.

More specifically, there are apparently 18 sites in our brains, where OPN3 photoreceptor proteins are located. These regions will supposedly react favourably to exposure to light, even when that light is filtered through tissue and bone.

The Valkee itself looks a lot like a personal music player, complete with earbuds. Instead of emitting music, however, these buds contain fiber optic lights.

By turning the device on and sticking the glowing fibers in your ears for about ten minutes a day, it is claimed that your brain will receive enough light to send the SAD packing.

Does it sound like quackery? A great deal of people would certainly say so.

Not among those people, however, would be a group of scientists from Finland's University of Oulu.

In two clinical trials, they had people with severe SAD use the device daily, for 8 to 12 minutes a day.

Afterward, when those people completed a BDI-21 questionnaire (a standard for assessing depression), it was found that 92 percent of the subjects in the first trial had completely recovered.

The information presented by the company is definitely somewhat difficult to sort out, although it appears that the results of the second trial were similarly encouraging.

A placebo group was included in at least one of the trials, to ensure that people weren't feeling better merely because they expected to.

To read more about the Valkee device visit their website

Converting Infrared radiation into visible light

Jeppe Seidelin Dam and colleagues at the Technical University of Denmark in Roskilde are developing a device that can convert infrared radiation into visible light. Attached to a digital camera fitted with an infrared flash, it could detect tumours by recording the telltale pattern of infrared light they reflect.

"This would allow a surgeon to quickly determine if the entire tumour has been removed before finishing an operation," he says.

At the heart of the system is a multilayered crystal of potassium titanium oxide phosphate in which the infrared photons from the object to be imaged interfere with photons from an infrared laser, also fired into the crystal. The interaction shifts the wavelength into the visible spectrum while preserving the image information, allowing it to be captured by a normal camera.

Mirror amplifiers

The idea was first explored in the 1970s, but improvements to methods for growing crystals since then have improved the resolution of the device 300-fold. By placing a pair of mirrors on either side of the crystal so that the laser light reflects back and forth, the team increased the odds of its photons interfering with infrared photons from the object.

"We pass the same photons through the crystal up to 100 times," says Dam. The crystal was able to capture an infrared panorama with a resolution of 200 by 1000 pixels, the team says.

The device could be placed in front of a digital camera lens like a filter, and be used to take thermal photographs or video. Shrinking it down to a size suitable for everyday use should not be difficult, says Dam. "These are basically the same components that are in green laser pointers."

While current infrared colour imagers need to run at -200°C and cost around $100,000, Dam says that an upconversion imager would run at room temperature and cost about $10,000.

Stefano Bonora of the University of Padua, Italy, calls the upconversion technique "really interesting" for its potential to generate infrared images at room temperature. Such detectors are lacking at the moment, he says.

Journal reference: Optics Letters, DOI: 10.1364/OL.35.003796

MIT generates photovoltaic power without sunlight

With heat, tungsten, and a silicon cell, MIT researchers have been developing a different way to get power from photovoltaics without sunlight.

Photovoltaic cells work best with light hitting them at certain wavelengths.

Ultra-violet and infrared waves, for instance, can be tough for semiconductors to absorb in order to generate electricity. But engineers at MIT have designed a system that converts heat into specific light wavelengths, custom fit for a solar cell. And possibly, custom fit for miniature electronics as well.

Such thermo-photovoltaic systems have been around for a while, but they haven’t performed as efficiently as the silicon chip “micro-reactors” described recently in the journal Physical Review A. Etching a pattern of nanoscopic pits and ridges into a bit of tungsten, the researchers created a thermal material that can partner up with a photovoltaic cell to absorb more light radiation.

The tungsten heats up and glows, with the design on its surface controlling the way light behaves. According to the study, the sculpted pits act resonators, emitting light with wavelengths best suited for uptake by the PV cell.

Need a recharge? Just add heat. This could come from the sun but doesn’t have to. For the study, the engineering team used the hydrocarbon butane. So in the future, butane might power more things in your pocket than your cigarette lighter.

They also developed a device that could draw heat from a decaying radioisotope. With such a heat source, years could pass between recharges. The researchers have long, dark space missions in mind.
Co-author Ivan Celanovic says in MITnews:

Being able to convert heat from various sources into electricity without moving parts would bring huge benefits, especially if we could do it efficiently, relatively inexpensively and on a small scale.

The silicon chip micro-reactors are shown above without PV cells attached to their sides. According to Celanovic, the devices are three times as efficient as lithium-ion batteries of similar size and weight. Yet the research team isn’t stopping there. They hope to one day triple even that

“The Arctic Light” time-lapse video

Norwegian photographer Terje Sørgjerd of TSO Photography has captured on film a phenomenon of light he claims the many scientists he’s spoken to have yet to name.

Hence, he has christened it “The Arctic Light,” which occurs in the two to four weeks before the Midnight Sun and is caused by the sun dipping just below the horizon before rising again. Simply stunning.

Replicate Tron Light Cycle

A designer has created ten street-legal replicas of the Tron Light Cycle.

The bikes are available to rent from Parker Brothers Choppers, based in Florida, USA.
 
See a video of the bike in action here:

The Germicidal and Sanitising effect of UV-C Light

UV-C light is the name for a certain spectrum of the (invisible) light. UV-C light is formed by the light in the range between 200 and 280 nm. This light is very much suitable for the so-called UV-C disinfection and is everything that is being done to terminate microorganisms with the help of UV-C energy.

UV-C lamps are especially produced for these purposes. Mostly we use mercury to generate the specific UV-C radiation. The lamps are coated specifically in order to burn a minimum of 8,000 hours and retain 80% of the initial UV-C energy. After 8,000 burning hours it is recommended to replace the lamps.

UV-C disinfection is applied to water, air and surfaces. Benefit of the UV-C application is that no chemicals need to be added to the air or water and the composition of the air or water does not alter. Moreover, the system is very economic compared with many other disinfecting methods. It goes without saying that UV-C disinfection is a very environmental-friendly and safe technique.

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