Tag Archives: LED

LED-equipped fishing nets help protect wildlife from unintentional captures

Green light-emitting diode (LED) lights can help protect wildlife from fishing nets, new research reports.

Image credits Paul Lee.

Affixing green LED lights to fishing nets can significantly reduce the catch of nontargeted animals such as sharks, squids, or turtles, according to a team led by researchers from the Arizona State University. The addition of these lights doesn’t impact the quantity or quality of desired catch species (i.e. commercially-available fish), which helps raise confidence that fisheries will adopt the measure. That being said, the installation of these lights comes with a significant upfront cost per net, which many fisheries may not be able to afford.

Beyond practical concerns, however, the findings showcase that it is possible to maintain our current fishing efficiency while insulating species that aren’t desired from capture.

Lights in the deep

Coastal fisheries routinely use gillnets, devices that resemble chain-link fences, to capture fish. These nets are deployed for up to several days at a time and capture virtually every kind of marine wildlife that cannot fit through their holes. Undesired captures (“bycatch”) are tossed overboard once the nets are recovered. These animals experience very high rates of death following this, adding up to significant pressure on marine species such as dolphins and sea turtles. It also impacts the fisheries’ bottom line, as personnel waste time removing these animals from the nets.

In other words, both business and nature lose out from the use of gillnets.

John Wang, a marine ecologist at the National Oceanic and Atmospheric Administration (NOAA), and his colleagues previously designed illuminated nets in order to protect turtles from becoming bycatch, back in 2016. Turtles seem to be particularly good at noticing green light, and these nets cut down on turtle bycatch by 64%. The current study builds on those findings, examining whether other marine animals could benefit from the same idea.

It turns out, they would. The authors worked with small-scale grouper and halibut fisheries in Baja California, Mexico, as the area is known for its large populations of turtles and other large marine species. They deployed 28 pairs of nets, one of each being equipped with groups of green LED lights every 10 meters. The team gauged their efficiency by identifying and weighing the animals each net captured overnight.

Nets outfitted with lights captured 63% less bycatch overall. Per species, they reduced bycatch by 51% for turtles, 81% for squid, and 95% for elasmobranchs (sharks and rays) — the last one being the most “gratifying” result for the authors, as shark bycatch in the Gulf of California is “a huge issue”.

Fish capture was not affected by the lights. However, the LEDs cut down on time wasted by fishermen on hauling and unloading bycatch, and on untangling the nets, by half. The only drawback so far, according to Senko, is the upfront installation costs of the lights: around $140 per net. Some fisheries, especially those in poorer areas such as Indonesia and the Caribbean, simply can’t afford this price per net, they add. The team is toying with using fewer lights and having them be solar-powered rather than battery-powered to reduce some of these costs. Meeting the needs of fisheries is essential for the success of this project, as they are the ones who will decide on using the LED nets or not.

Exactly why some animals seem to avoid lights, and why they do so more than others, is still up for debate. While it is possible that some species’ better eyesight helps them perceive the lights more clearly, it’s very unlikely that this is the cause — any species with sight can see these lights, after all.

The paper “Net illumination reduces fisheries bycatch, maintains catch value, and increases operational efficiency” has been published in the journal Current Biology.

Samsung may be on the brink of self-emissive QLEDs

Researchers at Samsung Electronics recently described a new method that extends the lifetime and efficiency of quantum dot light-emitting diodes (QLEDs). Although researchers are still not sure if they will ever be able to commercialize self-emissive QLED displays, this technology may become a defining component of flagship TVs and displays in the future.

Samsung’s commercially available QLED TV sets don’t actually use quantum dots as the light source. But it happen as early as 2025, South Korean researchers say. Credit: Amazon.

Quantum dots are artificial nanoscale crystals that can transport electrons and have varied properties, depending on their shape and material. Researchers first noticed in the early 1980s that if they made semiconductor particles small enough, quantum effects would come into play — enter the world of quantum dots.

What we now know about quantum dots is that their optical properties can be finely tuned depending on their size. For instance, these nanoparticles can be made to emit or absorb specific wavelengths of light — which is essentially color — by controlling their size. A 3-nanometer quantum dot can convert a spectrum of light into green while a 6-nanometer quantum dot gives off the color red.

Due to their appealing physical properties, quantum dots can be employed in a wide range of applications in such areas as electronics, photonics, information storage, solar energy, medicine, sensing, or medicine — to name just a few.

Most people have heard of quantum dots because of TV screens. Samsung Electronics and LG launched the first QLED TVs in 2015.

However, these TV sets do not use QEDs as a light source. Instead, a liquid crystal display (LCD) acts as the backlight, which is absorbed by a film of quantum dots that emits luminance. But in the future, self-luminating QLEDs might become a reality.

In a new study published in the journal Nature, researchers at Samsung, led by Dr. Eunjoo Jang and Dr. Yu-Ho Won, improved the structure of a quantum dot made out of indium phosphide.

The study describes how the novel structure prevents oxidation of the core and prevents energy from escaping by wrapping the quantum dot into a thick shell.

Results show that the quantum dot diodes have a lifetime of a million hours. Their efficiency also improved by 21.4% compared to the previous record holder. Another important achievement was the usage of indium phosphide, which is non-toxic and environmentally friendly. Most QLED research has employed cadmium, which has the highest performance as a light source due to its extraordinary malleability and integrity. The problem is that cadmium is toxic.

Quantum dots are both photoluminescent and electroluminescent, both properties that will be at the core of the next-generation of displays. Compared to organic luminescent materials used in organic light-emitting diodes (OLDEs), quantum dot-based diodes have purer colors, longer lifetime, lower manufacturing cost, and lower power consumption. And since quantum dots can be deposited on any structure — you can literally spray or paint them on surfaces — QLEDs can be flexible or printed.

Samsung seems very serious about this technology. In October, it vowed to invest $11 billion by 2025 to produce genuine, self-luminating quantum dot displays. The South Korean tech giant has so far over 170 patents on element structure in QLEDs.

natural light led

The LED sun: artificial light completely mimics properties of natural sunlight

natural light led

In many ways, society was transformed by the advent of the light bulb. Suddenly, people could now stay up late, work, study or enjoy each other’s company without being at the mercy of the sun. A side effect, however, is that our bodies natural wake/sleep patterns have been considerably altered and artificial light is nothing like the real deal — the sun’s life-nurturing rays which are known to have a significant impact on our health and mood. In an effort to help people who spend long hours in poorly lit offices or live in areas with little sunlight (Beijing, anyone?), a team of Italian engineers has developed a remarkable LED-based lighting system which mimics natural sunlight. Yes, this is a low-input LED sun!

led sun

The sunshine we love to greet each morning isn’t exactly the same as the rays leaving the sun. In between the outer atmosphere and Earth’s surface, the properties of light become altered through a process known as Rayleigh scattering. Ever wonder why the sky is blue? That’s Rayleigh scattering at work — the scattering of light due to molecules in the air, which can be extended to scattering from particles up to about a tenth of the wavelength of the light. This phenomenon is most effective at short wavelengths (the blue end of the visible spectrum), hence the color of the sky. Red just goes through.

natural light

CoeLux, the company behind the project, developed a thin coating of nanoparticles to simulate Rayleigh scattering. This way, miles of atmospheric scattering has been replicated within a few millimeters of space between the coating and the LED white light source.  Professor Paolo Di Trapani of Italy’s University of Insubria is the mastermind behind the 10-year-long project. By tweaking the shape, size and aspect ratio of the nanoparticles, Trapani’s team was able to replicate natural light from color and saturation to light quality. The result is spectacular — a LED light that looks like a skyline!

natural light

According to CoeLux, the light is indistinguishable from natural light for humans, cameras or computers alike. I’m as skeptical as you are, but allegedly all of these photos are unaltered.

light-real-simulation-design

If you’re interested in adding something like this in your home, you can choose from three lighting settings: Mediterranean, Tropical, and Nordic. They are also working on additional offerings, including simulated daytime sequences (sunrise through sunset) and color variations to reflect different kinds of weather conditions. At a few tens of thousands of dollars per installation, this might be a bit stiff for the average buyer. Nevertheless, this is extremely impressive and once the pricing goes down, indoor lighting might be transformed forever.

lighting natural system

Check out Prof. Trapani’s explanation of how the system works below.

Transparent screen ilussion.

Novel material paves the way for atom-thin, invisible displays

Researchers from UC Berkeley have designed a millimeter-wide, light-emitting device that’s fully transparent when powered off. The material, just three atoms thick, could form the base for displays that would be invisible when turned off.

Transparent screen ilussion.

Image credits Steve Webel / Flickr.

The device is based on a novel material — a light-emitting, monolayer semiconductor. It was developed in the laboratories of Ali Javey, professor of Electrical Engineering and Computer Sciences at Berkeley, and its light-emitting properties were first reported on in 2015. However, the team hadn’t been able to construct an actual light-emitting device using the novel semiconductor by that time — mostly due to fundamental constraints of using LED (light emitting diode) technology in tandem with monolayer semiconductors.

They’ve been working hard to solve those problems, however — in their new paper, the team details how they’ve worked around these limitations, allowing them to scale down LED technology anywhere from a few millimeters to under the width of a human hair. The team made the devices wide and long, to make sure the devices emit light intense enough for our eyes to pick up on.

Now you see it, now you don’t

“The materials are so thin and flexible that the device can be made transparent and can conform to curved surfaces,” said co-author Der-Hsien Lien, a postdoctoral fellow at UC Berkeley.

The kind of LEDs you can buy right now are made from a semiconducting material, injected with positive and negative electrical charges. When electricity runs through these LEDs, electrons move from the positively-charged area into electron ‘holes’ on the negative side, releasing light in the process. That’s the fancy explanation. The simple explanation is that LEDs work pretty much the same way as an incandescent light bulb, the main difference being LEDs don’t ‘burn’ and they don’t generate heat — the light you see comes solely from the passing of current through a semiconductor material, not from heating something. This makes them last much, much longer than an incandescent bulb.

One of the fundamental challenges I mentioned earlier is to form a contact that can efficiently inject these charges — and it’s a particularly problematic one for monolayers because there’s physically very little material to work with. The team worked around this issue by engineering a device that only uses one contact on the semiconductor.

Gif of the device in action. Probes inject positive and negative charges into the light emitting device, which is transparent under the campanile outline, producing bright light. Credit: Javey lab

They layered the semiconducting on an insulator, then placed electrodes on the monolayer and underneath this insulator. This allowed them to apply an alternating current (AC) signal across the surface of the insulator. As the AC switches polarity from positive to negative (and vice versa), both negative and positive charges are present in the semiconductor at the same time — which creates light. The team showed that this mechanism works with four different monolayer materials, all of which emit a different colored light.

Soon-to-be

The team’s efforts amount only to a proof-of-concept right now; much more research needs to be done before their atom-thin material is ready for commercial use. Most notably, the team has to work on improving its efficiency. While the tools they can use to measure this device’s efficiency leave a pretty significant margin of error, the team says it’s probably 1% right now. Commercial LEDs, to put that into context, run at about 25-30% efficiency — usually.

“A lot of work remains to be done and a number of challenges need to be overcome to further advance the technology for practical applications,” Javey said. “However, this is one step forward by presenting a device architecture for easy injection of both charges into monolayer semiconductors.”

However, the concept is likely applicable to other kinds of materials and devices. Given its versatility, we’re likely to see the team’s device used in all manner of applications where an invisible display is necessary or desirable. We’re also likely to see it used for ‘cool’ applications — the team doesn’t write off the possibility that their research will lead to atomically-thin displays used for decoration, from skin to architecture.

The paper “Large-area and bright pulsed electroluminescence in monolayer semiconductors” has been published in the journal Nature Communications.

Synthetic Photosynthesis.

New, cheap artificial photosynthesis scrubs the air and produces fuel

A research team from the University of Central Florida has found a way to trigger photosynthesis in an inexpensive synthetic material. The technology could be used to scrub the air clean and produce ‘solar’ fuel from atmospheric CO2.

Synthetic Photosynthesis.

The team’s photoreactor, with a sliver of the MOF dangling inside.
Image credits Bernard Wilchusky.

Scientists the world over have been trying to re-create the process that plants rely on to feed in a synthetic material for years now, with some success. Photosynthesis-like reactions can be maintained in common materials such titanium dioxide under higher-energy UV light. But, since the lion’s share of energy released by the Sun lies in the violet to red wavelengths, the challenge lies in finding a way to keep it going under visible light. Up to now, we’ve known comparatively few materials that can do so, and they’re very expensive (think platinum or iridium compounds), keeping them far away from commercial applications.

Uribe-Romo, a chemistry professor at the UCF, and his students may bring artificial photosynthesis into the market. The team has found a way to trigger the reaction in an inexpensive synthetic material, offering a cost-effective way to turn atmospheric CO2 into fuel.

The system uses a class of materials known as metal-organic frameworks (MOFs) to break down the CO2 into its two compounds. Uribe-Romo’s MOF was constructed from titanium with a pinch of organic molecules to act as light-harvesting points and power the reaction. These molecules, called N-alkyl-2-aminoterephthalates, can be tailored to absorb specific wavelengths (colors) of light when incorporated in the MOF — the team went for blue.

They tested the system under a photoreactor — a battery of blue LED lights which looks like a tiny tanning bed — constructed to mimic the sun’s blue wavelength. Controlled amounts of CO2 were pumped into the photoreactor, and the MOF scrubbed it out then split it into two reduced carbon compounds — formate and formamide.

“The goal is to continue to fine-tune the approach so we can create greater amounts of reduced carbon so it is more efficient,” Uribe-Romo said.

He says that the next thing the team will be looking into is how to adjust their material so it can sustain the process under other colors of light. If they can pull it off, the system will gain hugely in versatility and could grow to become a significant carbon sink. Stations could be set up near CO2-producing areas, such as power plants, to capture the gas and use it to produce energy which could be fed back into the system. Or it could be fashioned into rooftops that homeowners can install to clean their neighborhood’s air while saving up on power bills.

“That would take new technology and infrastructure to happen,” Uribe-Romo said. “But it may be possible.”

The full paper “Systematic Variation of the Optical Bandgap in Titanium Based Isoreticular Metal-Organic Frameworks for Photocatalytic Reduction of CO2 under Blue Light” has been published in the Journal of Material Chemistry A.

Cheaper, brighter and easier to manufacture LEDs created from organic-inorganic hybrid class of materials

Florida Researchers have developed a new class of LEDs that may change the lighting and display industry of the future.

Hanwei Gao on left and Biwu Ma on right, looking at their new LED. ( Image Credit: Bruce Palmer/Florida State University)

Florida State University’s Hanwei Gao, an Assistant Professor of Physics and Biwu Ma, an Associate Professor of Chemical Engineering have already published their results in Advanced Materials, and their study has been well received. They basically used organometal halide perovskites: a type of material also used in some solar panels, which has a number of remarkable properties. In fact, perovskites have been hailed by many as potentially revolutionary for LEDs, but so far, a number of experiments have failed to obtain the desired efficiency.

But Gao and Ma pushed on, firmly believing in the material’s ability to deliver. They used the synergy of synthetic chemistry and device engineering to tweak the material properties, ultimately engineering the device architecture just as they wanted. The results are impressive. Not only is it much brighter, but it’s also cheap and fairly easy to make.

To put “brighter” in perspective, LEDs like those in your computer emit approximately 400 candelas per square meter – the candela is the measure unit for luminous intensity; these new LEDs go out at 10,000 candelas per square meter. Interestingly, this increase in luminosity doesn’t make things more expensive. In fact, the improved perovskites that the duo designed are more stable than standard hybrid perovskites in humid air, and this means that the production is not only cheaper, but also faster: it only takes about an hour to produce the material.

LED technologies are very important for reducing electricity consumption, with the U.S. Department of Energy asserting that LED lighting uses at least 75% less energy than regular incandescent lighting. However, while LEDs are more efficient, their implementation for general lighting has generally been slow, and there are many concerns about this sluggishness. Developing better materials and even better LEDs could speed up that process, but it could do even more than that: the display of most computers, laptops and smartphones uses LEDs, and again, new technology could not only decrease consumption, but also increase user experience.

Journal Reference: Bright Light-Emitting Diodes Based on Organometal Halide Perovskite Nanoplatelets.

 

Blue visible light can be used as insect killer, research shows

Keeping insects at bay is more than eliminating a simple nuisance – in many some parts of the world, it’s vital. Malaria, an infectious mosquito-borne disease kilss over 500,000 people every year, and the disease could be kept under control if the mosquito population was kept under control; this is where this study steps in.

Some insects provide many environmental services, but many others are simply regarded as pests. For farmers working the land or for people in the poorer areas, insects can be a huge problem, causing major economic damage, and sometimes causing life-threatening diseases. Many solutions have been proposed for such situations, but for the most part, farmers still use insecticide to kill pests and people in Africa use bed sheets and other physical protection against mosquitoes. But insecticides are toxic to humans and bed sheets only get you so much, so a better solution would be more than welcome. This is where blue light comes in.

Japanese researchers from Tohoku University describe in the journal Scientific Reports that certain wavelengths of visible light are lethal to certain species of insects. For instance, blue light (wavelength = 467 nm; lights of different wavelenghts have different colors in the spectrum) was nearly 100% lethal to fruit fly pupae, while ultraviolet A light (wavelength = 378 nm) was only about 40% lethal.

Image source: Hori et al, 2015.

They went on and found that pupae of the London Underground mosquito (Culex pipiens molestus) were killed by violet/indigo light (417 nm), while pupae of the confused flour beetle (Tribolium confusum) were killed by several different wavelengths of light, ranging from violet to blue. Of course, in nature, insects are also subjected to these wavelengths, but in the study, they were subjected to much more light than they would have naturally.

“We also investigated the lethal effects of various bluelight wavelengths (404–508 nm) on pupae of the mosquito Culex pipiens molestus. Blue light irradiation was lethal to mosquito pupae, although their tolerance was higher than that of D. melanogaster pupae”, researchers write.

Researchers also suggest that different wavelengths could kill different bugs, and that this technology could actually be used practically in many environments. The key thing here is that people would be able to selectivelly kill pests, while leaving friendly ones unharmed. It would also reduce pesticide use, making foods less dangerous for humans, but the downside is that it would take a lot of energy. Illuminating whole fields with blue LEDs is no easy feat, and I’m not sure how the economic side factors into this one (this wasn’t tackled in the study). If the price is lower, comparable, or even just a bit higher, then it would be avantageous to use. If it’s much higher, I’m not sure farmers would adopt the method.

Also, if you want to keep multiple insects at bay, you have to use multiple types of LEDs. UV light is by far the most efficient type of light, but it can also be harmful to mammals. All in all, a very interesting find, but there’s still a way to go before this can be used practically.

Journal Reference: Masatoshi Hori, Kazuki Shibuya, Mitsunari Sato & Yoshino Saito. Lethal effects of short-wavelength visible light on insects. Via Nature.

LightPaper

Lightpaper prints LEDs and ink on incredibly thin surfaces

When I first heard about 3-D printing, I was completely stoked. The whole concept blew me away and changed forever what I thought of ‘printing’. We now also know about machines that print metals, food and even human organs, why not light too? While not a 3D printer, Rohinni’s Lightpaper technology can be credited as innovative; once more lifting the margin and changing the paradigm of what can be printed and on what.

LightPaper

Credit: Rohinni

Basically, Lightpaper is made by printing incredibly tiny LEDs with ink on a conductive sheet. The sheet is then sandwiched between two other layers and sealed. The tiny diodes are about the size of a red blood cell, and randomly dispersed on the material. When current runs through the diodes, they light up.

Rohinni

credit: Rohinni

Organic light emitting diodes (OLDs) have allowed TV screens thinner than tenth of an inch to be manufactured, but this isn’t what Lightpaper is intended for, according to Rohinni CMO Nick Smoot. The company is interested in markets such as the automotive industry, where they could make excellent taillights, or branding. Lightpaper could be used to light up logos on a mobile phone or other devices. Indeed, there would be a great deal of marketing efforts that could benefit from cheap LEDs that are thin enough to be applied to virtually any surface.

It does have some drawbacks. For one, because the diodes aren’t distributed evenly, the Lightpaper isn’t as bright over the whole surface. The effect isn’t noticeable for most of its applications, but it could use improving.

The quantum dot device structure shown with a transmission electron microscopy (TEM) image of a cross-section of a real device.

Forget incandescent light bulbs, make way for quantum dot LEDs

The quantum dot device structure shown with a transmission electron microscopy (TEM) image of a cross-section of a real device.

The quantum dot device structure shown with a transmission electron microscopy (TEM) image of a cross-section of a real device.

Capable of illuminating in a wide array of pure colors and operating at high efficiency, quantum dot LEDs are set to become the future’s foremost illuminating medium. However, at this time, these fantastic quantum dot light emitting diodes are limited by a physical effect which triggers after a certain photon barrier is crossed, becoming highly inefficient thereafter. This has made them commercially nonviable, however recent work by the Nanotechnology and Advanced Spectroscopy team at Los Alamos National Laboratory could provide a working solution that might usher in a new age of lighting.

Quantum dots are nano-sized semiconductor particles whose emission color can be tuned by simply changing their dimensions. They feature near-unity emission quantum yields and narrow emission bands, which result in excellent color purity.

“QD-LEDs can potentially provide many advantages over standard lighting technologies, such as incandescent bulbs, especially in the areas of efficiency, operating lifetime and the color quality of the emitted light,” said Victor Klimov of Los Alamos.

Chances having that you’re using at least one incandescent light bulb in your home or office right now. The truth is these should be called incandescent radiators, since these only generate 10% light from provided power, while the rest of 90% is lost as heat! Using LEDs, however, electricity is converted directly into light resulting in a much more efficient process.

QD-LEDs are particularly attractive due to their spectrally narrow, tunable emission, and ease of processing. This is why scientists in solar cell research are so seduced by them. In the past few years massive leaps forward in the QD-LED research have been made, however one major obstacle hindered their market introduction. At high current QD-LEDs perform poorly, a problem known as ‘droop’. This means you can only use them at low currents or low brightness, obviously not very attractive for most people who need vivid light.

The Los Alamos scientists found that the ‘droop’ is caused by an effect called Auger recombination. In this process, instead of being emitted as a photon, the energy from recombination of an excited electron and hole is transferred to the excess charge and subsequently dissipated as heat. In their paper, published in the journal  Nature Communications, the researchers describe the mechanics efficiency losses in QD-LEDs and propose two possible solutions for circumventing the problem.

The first approach is to reduce the efficiency of Auger recombination itself, which can be done by incorporating a thin layer of cadmium selenide sulfide alloy at the core/shell interface of each quantum dot. A second strategy tackles charge imbalance by better controlling the flow of extra electrons into the dots themselves. This can be accomplished by coating each dot in a thin layer of zinc cadmium sulfide, which selectively impedes electron injection.

“This fine tuning of electron and hole injection currents helps maintain the dots in a charge-neutral state and thus prevents activation of Auger recombination,”  Jeffrey Pietryga, a chemist in the nanotech team.

Misfit scales found on the lantern of the Photuris firefly. (c) Optical Express

Natural brightness: fireflies inspire LEDs with 55% more efficiency

A firefly specimen from the genus Photuris, which is commonly found in Latin America and the United States and served as the inspiration for the effective new LED coating. Credit: Optics Express.

A firefly specimen from the genus Photuris, which is commonly found in Latin America and the United States and served as the inspiration for the effective new LED coating. Credit: Optics Express.

We’ve featured countless research here on ZME Science where important scientific and technological advancements were made after scientists sought inspiration from nature, be them  high-tech surfaces (butterfly) or robots (leaping lizard). Recently, researchers at Canada’s University of Sherbrooke managed to improve LED efficiency by 55% after they applied a coating etched with a profile similar to that of firefly scales.

Fireflies emit the light for which they’re so recognized and loved through a chemical reaction that takes place in specialized cells called photocytes. The light produced is then emitted through a special part of the insect’s exoskeleton called the cuticle. Since the propagating light travels at different speeds through the cuticle than it does through air, the mismatch causes the light to reflect back dimming the glow.

Misfit scales found on the lantern of the Photuris firefly. (c) Optical Express

Misfit scales found on the lantern of the Photuris firefly. (c) Optics Express

Some fireflies, however, like those belonging to the genus Photuris have specialized scales on their cuticles that look like stacked roof tiles that help tone down internal reflection. The same internal reflection issue is also present in man-made LED bulbs. The researchers were intrigued by this and tried to see if they could improve brightness in LEDs through a similar method employed by the Photuris firefly.

“The most important aspect of this work is that it shows how much we can learn by carefully observing nature,” says Annick Bay, a Ph.D. student at the University of Namur in Belgium who studies natural photonic structures, including beetle scales and butterfly wings.

The researchers used a laser to etch a profile into that coating, similar to that of the edges of the firefly scales, that was applied on a gallium nitride LED. The team remarkably reported an increase in efficiency of 55%, findings which were reported in the journal Optics Express in two papers (1 and 2). Hopefully the technique used might be employed in large manufacturing of LEDs.

“We refer to the edge structures as having a factory roof shape,” says Bay.  “The tips of the scales protrude and have a tilted slope, like a factory roof.” The protrusions repeat approximately every 10 micrometers, with a height of approximately 3 micrometers. “In the beginning we thought smaller nanoscale structures would be most important, but surprisingly in the end we found the structure that was the most effective in improving light extraction was this big-scale structure,” says Bay.

source: Optics Express

NASA to test sleep-aid coloured light bulbs

Space flight insomnia is quite a common issue, one for which space agencies don’t have a definite answer yet – but they’re working on it; one thing NASA plans to do is swap a fluorescent panel with a solid-state lighting module (SSLM) containing LEDs which produces a blue, whitish or red-coloured light depending on the time.

Some studies concluded that this change will not only combat insomnia, but it will also fight against depression, sickness and proneness to fatigue related mistakes. Currently, over half of all active astronauts rely on sleep medication, at some point, to sleep and get rest. For $11.2 million, NASA hopes to use the science of light to reduce the astronauts’ dependence on drugs and improve their overall performance.

“On some space shuttle missions up to 50% of the crew take sleeping pills, and, over all, nearly half of all medication used in orbit is intended to help astronauts sleep,” a NASA report said in 2001. “Even so, space travellers average about two hours sleep less each night in space than they do on the ground.”

Both humans and animals on Earth follow what is called a circadian rhythm – a 24-hour biological cycle involving cell regeneration, urine production and other functions critical to health. Basically, your body’s rhythm is driven by a circadian clock, and rhythms have been widely observed throughout the entire life forms – plants, animals, fungi and cyanobacteria.

What NASA wants to do is simulate a night-day cycle to minimise sleep disruption caused by the lack of a natural environment onboard missions such as the International Space Station. However, what I really love about this idea is that it could eventually help out a big part of the population on Earth which is suffering from sleep disorders.

“A significant proportion of the global population suffers from chronic sleep loss,” said Daniel Shultz at the Kennedy Space Center. “By refining multipurpose lights for astronauts safety, health and well-being in spaceflight, the door is opened for new lighting strategies that can be evolved for use on Earth.”

Via NASA

Re-Timer Glasses

Curing jet lag with timezone adjusting LED glasses

Re-Timer GlassesAlong with technology came a series of new afflictions that plagued mankind. Most of them are psychological, like internet addiction or the ever worrisome jet lag. The latter is a big problem for millions of people regularly traveling in different time zones, causing them to miss hours of sleep, feel extremely tired, not eat well and feel depressed. Australia’s Flinders University sleep researchers recently released on the market an interesting pair of goggles called the Re-Timer that uses LEDs to regulate light flow and reset your internal clock.

Jet lag has a sort of natural correspondent, although nothing of the sorts as extreme, in the form of seasonal shifts of day and night hours. This is something commonly known as winter blues, and many of us suffer from it, especially when the number of daylight hours is low. Staying too much time indoors is also known to cause a similar affect on people. In all, they all point to the same thing – disruption of the body clock through inconsistent light exposure.

Our bodies have used sunlight to regulate our sleeping and waking pattern, which in term governs our mood and well-being, for tens of thousands of years; early ancestors for much more. The researchers’ device concentrates on this exact light mismatch to counter effects like jetlag, by emitting a soft green LED light into your eyes.

“The light from Re-Timer stimulates the part of the brain responsible for regulating the 24-hour body clock,” Professor Leon Lack said.

“Body clocks or circadian rhythms influence the timing of all our sleeping and waking patterns, alertness, performance levels and metabolism.”

Those who wanted to sleep and wake up earlier should wear the device for 50 minutes in the morning, while those who want to sleep and wake later should wear them for 50 minutes before bed to delay the body clock. The glasses can be worn while completing normal daily tasks such as working on the computer or reading.

“Our extensive research studies have shown that green light is one of the most effective wavelengths for advancing or delaying the body clock, and to-date is the only wearable device using green light,” Prof Lack said.

“The glasses have been designed to be user friendly and comfortable to wear so people can go about their normal activities wearing them at work or at home.”

The device is explained in a video featured below. The Re-Timer is commercially available for $258. Scientific research that backs the Re-Timer features can be found here.



via Dvice

zme prize 1

[ZME Contest] WIN solar charger and Rechargeable LED Work light

Hey, guys!

We’ve received some great feedback from our previous contest, when we offered an awesome DNA portrait to one of our readers. Naturally, we’d like to follow with yet another giveaway and hopefully turn this into a frequent feature on ZME Science. It’s the least we can do for all your generous support you’ve shown us along the years, especially recently since we’ve grown, all thanks to you.

This edition’s contest comes with not one, but two prizes, offered by Earth Tech Products, who are also ZME readers.

1st prize – Power Monkey Extreme Solar Charger (iPad supported)

zme prize 1 The Power Monkey Extreme Solar Charger is the ultimate portable solar charger money can buy! The power monkey extreme has all of the durability and portability of the original Power Monkey, except it is even more powerful. This durable solar charger is made tough to withstand whatever adventure you get up to it is even waterproof! Made with the outdoor adventurer in mind and powerful enough to even charge an Ipad (iPad compatible cable included) or tablet computer the power monkey extreme is truly the most versatile solar cellphone charger available today. A multifaceted solar charger that can charge a whole slew of electronic devices like: cameras, gps devices, mini and tablet computers, Apple Ipads, cell phones, smart phones, portable gaming devices, Ipods and more! This eco-friendly portable solar charger utilizes advanced solar technology to charge even in low-light or cloudy conditions insuring you will never be without much needed power, where ever your journeys take you.” (official product description)

 

2nd prize – Hand Crank Rechargeable LED Work light

zme prize 2 The Hand Crank Rechargeable LED Work light is a highly versatile work light that provides brilliant illumination where ever or when ever you need it. Powered by the built-in hand crank, it never needs batteries and its lights have multiple functions. It has a built-in hanging system with a hook that can be hung virtually any where. That’s not all, it also comes with a magnetic base allowing you to firmly stick it on any metal surface. The ultra bright LEDS never need replacing and have four different settings. Low and high settings allow you to choose just the amount of light you need. It even functions as a flashing emergency warning light, with 3 red LEDS that light up and flash. The light is even rain proof, insuring you can have light in nearly any weather conditions. The light can even be recharged via an AC plug (not included) insuring that your light will be ready for work when ever you are. It makes a very sensible gift for the handyman in your life.” (official product description)

To enter the contest, leave a comment below this post telling us how would you use one or both of these eco-products. The most creative two response will be chosen as the winning entries.

Shipping is free for US citizens. Outside US citizens will have to support shipping taxes.

Good luck!

 

 

DEADLINE: July 27, 2012 

 

 

UPDATE: FIREHIKER (solar charger) and Casey (LED light) were chosen as the winners of the contest. Thank you everyone for your submissions – it’s been really great reading them.

Fantastic Sustainable Eco Home in Ipswitch

4 Super Environmentally Friendly Houses in the UK

Malator in Druidstone, Wales

‘Future Pod Design in the Earth’ in the Welsh Valleys

Touted as an architectural masterpiece, contemporary houses don’t come as cool looking as this capsule embedded in the ground. From the outside it looks like a pod from a sci-fi movie, and the same goes for the interior. It’s turf roof, steel chimney and peephole doorway gave it the nickname ‘ Teletubby house’ from the locals. Whilst looking futuristic, Malator’s design is very simple, essentially based around one room divided by prefabricated coloured pods. Although a modern concept, the pod manages to meld in with its natural surroundings.

Sustainable House Project  – Ipswich

Fantastic Sustainable Eco Home in Ipswitch

Fantastic Sustainable Eco Home in Ipswitch

This eco friendly and energy efficient development forms part of an innovative project of individual quality houses. It’s a detached three-storey property with 4/5 Bedrooms, 3 Bathrooms, Living Room, Family Room, Dining Room, Kitchen, Utility, Hall, and a balcony overlooking the garden. Outside features ample car parking. This new development of eco-friendly home is proving to continue to be very popular. The house is crafted using natural materials, allowing the traditional character to shine through.

Solar panels and LED lights help reduce energy outage, and all the walls and floors are heavily insulated, retaining any heat. The accommodation makes the most of all light with large windows, glazed porches and internal balconies. Eco Houses for sale in the Ipswitch area at Zoopla are plentiful and you will be able to find your own build.

 Sedum House, North Norfolk Coast

Sedum House, North Norfolk Coast

Sedum House, North Norfolk Coast

This amazing looking house is said to be the future in houses. Sedum house is set in steep sand hill inland in North Norfolk Coast, where the earth hides deep within itself all the bedrooms of the property. Sedum House has ground level windows. Another great design consideration was focussing the main point around the sun. The impressive wooden hood covers the main living rooms on the first floor – this keeps the heat off the glass windows during summer, but in winter the house is not devoid of any sunlight. Four bedrooms of the house are buried in the tunnel, the ground cover provides energy free insulation. Not only energy efficient but very cool looking.

The ‘Zero Carbon House’ Project

The 'Zero Carbon House' Project

The ‘Zero Carbon House’ Project

This project has been designed and constructed as a highly efficient and low embodied energy house set on Unst, Shetland. It features a carbon energy system, which compromises of two micro wind turbines, an air to water heat pump, water battery heat store and control system. Taking Eco a step further, a high technology greenhouse for local food production has been erected. Food will be grown throughout the year inside, no soil or peat needed, as this high tech will do the job with just nutrients, water and LED lighting. They even went as far as using thermal imaging to identify any heat leaks within the structure.

 

A typical light emitting diode, captioned here only for illustrative purposes. Not the actual LED used in the presently discussed research.

MIT engineers create LED that has 230% efficiency. Thermodynamics laws still in place

A typical light emitting diode, captioned here only for illustrative purposes. Not the actual LED used in the presently discussed research.

A typical light emitting diode, captioned here only for illustrative purposes. Not the actual LED used in the presently discussed research.

A group of researchers at MIT have successfully managed to create a light emitting diode (LED) that has an electrical efficiency greater than 100%. This might sound preposterous, and against everything you learned in physics, however the system is still governed by fundamental laws of thermodynamics.

This extraordinary power conversion efficiency was obtained by a decrease in applied voltage to an LED with a small band gap. As the voltage was steadily halved, it was observed that the electrical power was reduced by a factor of four, but the light power emitted only dropped by a factor of two. Where this extra energy come from? The key here is lattice vibrations caused by heat coming from the surroundings. Thus, the device’s efficiency is inversely proportional to its output power and diverges as the applied voltage approaches zero. Over 100% efficiency was reached in the experiments, all without violating energy conservation principles.

The best efficiency was reached when such a LED was plugged to 30 picowatts, powering a LED which produced 69 picowatts of light, in the trillionth of a watt order – 230% efficiency. There’s a huge flaw in this otherwise miracle system – the power itself is simply too small to light anything. The principle itself is terribly exciting and the MIT scientists involved in the research are confident these findings will aid new advances in energy-efficiency electromagnetic communication.

Results were described in a recently published paper in the journal Physical Review Letters.

MBE machine grows gadgets one atom at a time

The MBE machine capable of growing gadgets

Dubbed MBE, after the intricate molecular beam epitaxy process, this device developed by scientists at Sharp Laboratories in Oxford, England, can actually grow electrical components at a dazzling precision atom by atom.

This is where razor sharp technology is at, as far as manufacturing goes, and this monstrous-looking device is capable of transferring atoms from one place to another almost individually, as tiny crystalline structures are layered together to form objects and thus build the basis of high tech electronics.

Using the MBE, Sharp engineers were able to build anything from lasers to LEDs and even solar panels. It’s a highly complex and demanding machine, however, one which requires almost space like vacuum inside of the working chamber for components to come out like they’re supposed to. Without vacuum, impurities would make the properties of the layered molecules useless and disrupt the whole process.

Magnetic handles manipulate materials within the MBE

Magnetic handles manipulate materials within the MBE

Inside of it, although perfectly isolated from the rest of the world and trapping a little piece of cosmos into its belly, the whole MBE process is fully controlled by the scientists who can dispose molecules in any they see fit. The whole operation is maneuvered through use of magnetic poles, with a handle on the outside of the MBE, to move the wafer into position. A pyrometer lets operators measure temperature remotely too, and despite being separated by a physical barrier, it’s possible for the scientists to have complete control.

RELATED: Smallest 3D printer

Dr Ian Thompson, Director of Business Development at Sharp Laboratories of Europe explains that “whatever your substrate is, the crystal structure will be what the first atom mimics. Whatever you layer on top follows its orientation.” The process is very controlled and, inside the MBE, a component literally grows before scientists’ eyes through the tiny circular viewing windows along its edge.

An interesting profile of the MBE machine can viewed below directly from one of Sharp’s leading engineers.

source: Human Invent