A portrait of Earth’s dirty atmosphere

Here’s a mind-blowing view of the Earth that you’ve probably never seen — or even thought of — before. Dubbed “Portrait of Global Aerosols” by NASA, this is the kind of imagery that climate scientists use to analyze the Earth’s atmosphere, the weather, and trends such as global climate change.

Now, first things first: The Earth doesn’t actually look like this from space (alas). Rather, this is an image output by the Goddard Earth Observation System Model, version 5 (GEOS-5). GEOS-5 is an almighty piece of software that runs on a supercomputer at NASA’s Center for Climate Simulation in Maryland.

In the case of this image, GEOS-5 is modeling the presence of aerosols (solid or liquid particles suspended in gas) across the Earth’s atmosphere. Each of the colors represents a different aerosol: Red is dust (swept up from deserts, like the Sahara); Blue is sea salt, swirling inside cyclones; Green is smoke from forest fires; and white is sulfates, which bubble forth from volcanoes — and from burning fossil fuels. The full-size version of the image is particularly mesmerizing, with beautiful swirls of Saharan sand in the Atlantic, and perhaps the tail end of the Gulf Stream circling around Iceland.

It’s hard to be certain, but it seems like the US east coast, central Europe, and east Asia are burning a lot of fossil fuels. Japan, of course, sits on the edge of the Pacific Ring of Fire, so the sulfates there could be from volcanoes. The smoke in Australia is probably from forest fires — but the large volume of smoke from the Amazon rain forest and sub-Saharan Africa is curious. Are these forest fires, or the large-scale burning of wood for heat and power?

As you can imagine, the amount of raw data required to produce such imagery is immense. Weather modeling is still one of the primary uses of supercomputers. To create the Portrait of Global Aerosols, GEOS-5 will have aggregated the measurements from hundreds of weather stations across Earth, along with data from the four NASA/NOAA GOES weather satellites. So you have some idea of the complexity of the GEOS-5 model, the resolution of this image is 10 kilometers (6 miles) — meaning the Earth has been split into regions (“pixels”) of 10km², and then the atmospheric conditions are simulated for each region. The surface area of the Earth is 510,072,000km², which means the total number of regions is around 5 million.

Each of these 5 million pixels might have megabytes or gigabytes of weather data associated with it — and of course, in any given area, the weather in each pixel interacts with those around it. This gives you some idea of how much data needs to be processed and moved around — and it only becomes exponentially more complex as sensors improve (producing more data) and as you increase the depth of your analysis. In the case of climate change, for example, scientists are modeling decades or even centuries of data to try and divine some kind of pattern — a task that taxes even the most powerful supercomputers. If you’ve ever wondered why we keep building faster and faster supercomputers, now you know why.

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Is it worth investing in a high-efficiency power supply?

If you’ve gone shopping for a power supply any time over the last few years, you’ve probably noticed the explosive proliferation of various 80 Plus ratings. As initially conceived, an 80 Plus certification was a way for PSU manufacturers to validate that their power supply units were at least 80% efficient at 25%, 50%, 75%, and 100% of full load.

The 80 Plus program has expanded significantly since the first specification was adopted. Valid levels now include Bronze, Silver, Gold, Platinum, and a currently unused Titanium specification level. The chart below lists the requirements a PSU must meet to be certified.

In the pre-80 Plus days, PSU prices normally clustered around a given wattage output. The advent of the various 80 Plus levels has created a second variable that can have a significant impact on unit price. This leads us to three important questions: How much power can you save by moving to a higher-efficiency supply, what’s the premium of doing so, and how long does it take to make back your initial investment?

Power supply pricing and premiums

First, here’s an overview of 80 Plus PSU pricing at various wattages. We created this data from NewEgg results, but only picked units from well-known vendors. Generic products from companies like CoolMax aren’t a part of these results. When we priced units, we opted for the lowest-cost unit from the same manufacturer.

Basic 400W-600W units are quite cheap these days, even from top vendors like Antec, Corsair, OCZ, and Silverstone. Prices start to climb by the 700W range; 1200W units are several hundred dollars.

The price premium for greater-than-80 Plus certification can be substantial. Below 800W, Bronze certification adds 4-20% to the list price of an 80 Plus unit. 80 Plus Gold PSUs are 35-61% more expensive within the same wattage category. Platinum-level power supplies are 90-100% more expensive; twice the price of a standard 80 Plus unit.

By way of example: Antec and Rosewill have $50-$60 80 Plus PSUs in the 501-600W category, while the 80 Plus Platinum products are $139 and $110 respectively. In the 701-800W division, Corsair has 80 Plus Bronze units for $84.95, and 80 Plus Platinum priced at $179.

At the highest end of the market, this changes slightly. Power supplies in the 1kW and greater category don’t put much of a premium on high-efficiency units. An 80 Plus 1200W PSU is $229; 80 Plus Gold is ~$258. 80 Plus Platinum is still significantly more expensive at ~$332.

You can’t save power that you aren’t using

Power supply efficiency is defined as the amount of power actually provided to the internal components, divided by the amount of power drawn at the wall. A 50% efficient PSU that’s tasked with providing 50W of power to a system will draw 100W from the grid. The extra 50W is lost as heat. A 90% efficient PSU would draw 56W in the same circumstances.

Even generic PSUs are far more than 50% efficient; in fact, 75-77% is fairly common. This means the amount of money you save from upgrading to a high-efficiency PSU is minimal if you don’t actually draw much power to start with. Electricity rates are charged by the kWh — if your system only uses 80W at idle, and idles 20 hours a day, you won’t see much benefit from an 80 Plus Platinum PSU as opposed to a regular 80 Plus.

How we tested

We’ve tested two pairs of PSUs from the same manufacturer and with the same rated power output (or close as we could get). Our first testbed was outfitted with two 750W power supplies from PC Power & Cooling. The first is a red Silencer with an 80 Plus certification. Overall listed efficiency for the unit is 83%. The manual breaks this down further, specifying that efficiency ranges from 82-85% depending on exact load.

The other 750W is a Silencer Mark II. It’s certified as 80 Plus Silver with an average efficiency of 85%. Efficiency isn’t broken down by overall load for this model.

The second testbed was configured with a brace of Thermaltake Toughpowers. The first is a 1200W Toughpower 1200A, the second is a 1275W Toughpower XT Platinum. The first unit is certified as 80 Plus, with a listed efficiency of up to 87%; the second’s efficiency is listed as up to 94%. Thermaltake doesn’t provide any additional clarity for either unit, so it’s not initially clear if those figures are for 115V or 220V operation.

Note: The 750W and 1200W figures cannot be cross-compared. We built two entirely different testbeds for this project. Putting a moderate load on a 750W PSU isn’t particularly difficult, while stretching the legs of a 1200W PSU took a bit more work.

Our test methodology was simple: We plugged in a Kill-A-Watt wall meter and measured the power consumption of each unit over 2.5 hours at both load and idle. The meter was reset in between each test for each PSU. Our wattage figures are the average load while the system was in each state, not spot checks on the meter. It’s true that this is a relatively simple, broad-spectrum test, but our goal is to compare simple, real-world savings; not metrics you can’t measure without expensive equipment.

Results

First, here are the idle figures for the four solutions:

The idle figures illustrate what we said earlier regarding the limited impact of increased idle efficiency as far as total power costs are concerned. Gains here are in line with claimed figures. Moving to the 80 Plus Silver 750W cuts idle consumption by roughly 3.6%; the 80 Plus Platinum reduces power consumption by 9.2%.

Load tests show the same gaps at higher power consumption. The 80 Plus Silver 750W Silencer Mark II is 4.5% more efficient than the original Silencer; the 1200W Toughpower XT Platinum is 8.8% more efficient than the 1200A power supply. Again, it matters where you start from. Saving 25W between the 80 Plus and 80 Plus Silver isn’t bad, but the XT Platinum knocks almost three times as much wattage off the 1200A’s main draw.

Clearly the efficiency of a top-end PSU can save you some scratch over the long term. Exactly how much depends on what you’re doing.

How much can you save?

Here, we’ve taken our data from all four power supplies and plugged it into various use equations over an entire year. Our first two graphs assume that the system is either in idle or under full load 24/7/365. Two different costs per kilowatt-hour are included: The US average, at 12.5 cents per kWh, and the current New York State average of 18.7 cents. These are simplistic assumptions, but they ballpark the maximum and minimum savings you’ll see if you never turn the system off.

At constant idle, the 750W 80 Plus Silver saves $4.38 to $6.56 over the course of a year. Upgrading to the 80 Plus Platinum drops between $18.63 and $27.87 back in your pocket.

At constant load, even the modest upgrade offered by the 750W 80 Plus Silver is worth $27-$40. The Toughpower XT 1275W saves you $80-$120 in power costs per year.

Granted, very few people are going to need a power supply under this type of continuous load, but there is a financial benefit to upgrading if you use this much power. At some point, however, we need to address the fact that the best way to save power is to turn the machine off or put it into hibernation.

Here are power usage figures and costs if we assume that the system is idle eight hours a day, under load for four hours, and off/hibernating for the remaining 12.

Heavy workers may still see an advantage from an upgrade; the Thermaltake 1275 XT Platinum will save from $19.57 to $29.38 a year. The smaller 750W upgrade is worth $6 to $9.

A dubious investment

The good news is that power supplies with better 80 Plus ratings really do deliver what they claim — there is a net reduction in total power consumption. If you burn a lot of power, Platinum units could be good investments and pay back their premiums in a year or two. Similarly, if you’re trying to minimize every last watt of consumption, this is one way to do it. The cost premiums, however, don’t add up anywhere but at the highest end. If you’re buying a 1200W unit, Gold is scarcely more expensive and Platinum will still pay back its initial up-front cost in a year or two.

Most of us, however, would be best served by turning the machine off or dropping into hibernation. The best way to save power is simply not to use it, and manufacturers currently charge huge premiums for marginal performance gains. If you’re upgrading from a cheap piece of junk (anything with words like Sparkle, Max, Tech, Sun, Bright, or Beam in the name is virtually guaranteed to be garbage), the premium is easier to justify. If you’ve already got an 80 Plus PSU, it’s a much harder sell.

The flip side is that PSU units go on sale fairly frequently, and a gold or silver unit can be trusted to provide an upgrade. It may not make much sense to buy a unit at a significant premium, but if you get a good deal, we recommend taking it.

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The first flexible, fiber-optic solar cell that can be woven into clothes

An international team of engineers, physicists, and chemists have created the first fiber-optic solar cell. These fibers are thinner than human hair, flexible, and yet they produce electricity, just like a normal solar cell. The US military is already interested in weaving these threads into clothing, to provide a wearable power source for soldiers.

In essence, the research team started with optical fibers made from glass — and then, using high-pressure chemical vapor deposition, injected n-, i-, and p-type silicon into the fiber, turning it into a solar cell. Functionally, these silicon-doped fiber-optic threads are identical to conventional solar cells, generating electricity from the photovoltaic effect. Whereas almost every solar cell on the market is crafted out of 2D, planar amorphous silicon on a rigid/brittle glass substrate, though, these fiber-optic solar cells have a 3D cross-section and retain the glass fiber’s intrinsic flexibility.

The lead researcher, John Badding of Penn State University, says the team has already produced “meters-long fiber,” and that their new technique could be used to create “bendable silicon solar-cell fibers of over 10 meters in length.” From there, it’s simply a matter of weaving the thread into a fabric. Badding says that the military is “interested in designing wearable power sources for soldiers in the field,” but unfortunately he falls short of actually demonstrating some woven fabric. As we can see in the picture above, the solar cell fiber certainly looks flexible — but we’ll have to take Badding’s word for it that it can turn right angles, and withstand everyday garment stresses, without shattering.

Moving forward, the potential for flexible, woven solar cells is enormous. On the most basic, immediate level, you can imagine a baseball cap or t-shirt that can recharge your smartphone. As we move towards bionic implants and other biomedical devices, though, there is a very pressing need to develop a wearable power source — and fiber-optic solar cells could certainly be it.

These fibers also have two other intriguing properties that still need to be investigated. Due to their three-dimensional cross-section, they can absorb sunlight from any direction — unlike their conventional, 2D siblings that lose much of their efficiency when the sun sinks below a certain angle. Further, according to Pier Sazio, another member of the research team, they used the same silicon injection method to embed photodetectors inside the fiber. Sazio doesn’t extrapolate on what this might lead to, but it’s fun to speculate: Awearable computer with built-in solar charging and high-speed networking? Neat.

Now read: LG produces the first flexible cable-type lithium-ion battery, or Creating cheap solar panels with an ion cannon

Research paper: DOI: 10.1002/adma.201203879 – “Silicon p-i-n Junction Fibers”

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EU seeks to reduce world’s energy usage, and double data center speeds, by replacing copper with fiber

Data centers are big and costly. Engineers all over the world are working hard at making servers and networking more efficient. Processors are using less power, cooling is getting easier, and evenrouters are reducing their footprint. Sadly, data centers are still using a gigantic amount of power, so the European Union is funding a trend away from traditional electrical data connections. Headed by the Fraunhofer Institute in Germany, project PhoxTroT aims at reducing power consumption by using light-based data connections, while at the same time increasing transfer speeds to two terabits per second (Tbps).

An article from Fraunhofer explains that this four-year project isn’t about reinventing the wheel — optical data transfer is already used around the world. Instead, PhoxTroT will be focused on taking existing technologies, combining them, and refining them into a system that will save money and use less energy while doubling connection speeds. “They will realize the optical transmission on a printed circuit board (‘on-board’), ‘board-to-board’ and also ‘rack-to-rack’. By combining these interfaces, it will also be possible to bridge longer distances within the foreseeable future,” says the article. This isn’t just a dolled-up fiber optic cable — this is taking the technology to the next level by integrating light-based data transfer throughout entire data centers on the individual server level, while increasing the effective range to hundreds of kilometers.

Not only is optical networking more power efficient and faster than its copper counterpart, but it’s also more robust in the face of disaster. After Hurricane Sandy took out a non-trivial amount of communications on the east coast of the United States, telcos went through and replaced copper lines with fiber-optic cables to update their network speeds and reliability. Electrical data transfer like typical coaxial and Ethernet cables still have a place, but it is slowly being overtaken in usefulness by optical data transfer. If PhoxTroT is a success, copper wiring will become even more of a niche.

With a little under twelve million dollars invested by the European Union, and eighteen different companies working together over the next four years, PhoxTroT can transform the data center into a much more eco-friendly and cost effective endeavor. Google‘s data centers alone draw 260 million watts continuously. A single Amazon data center in 2011 drew eight million watts continuously. Worldwide, data centers account for around 30 billion watts — a few percent of the world’s total power usage.

If these engineers can double the data throughput while using a small fraction of the power traditional networking uses, we’re talking savings of tens of millions of dollars per data center. The EU should be applauded for its efforts, and other countries and organizations should take a page out of its handbook in this instance. We’re saving money and saving the planet one data center at a time.

Now read: Will 100Mbps internet connections destroy the web as we know it?

[Image credit: Adrienne Serra & Alex]

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Rice University creates graphene/nanotube hybrid material that could redefine electronics and energy storage

What could possibly be cooler than graphene or carbon nanotubes? Rice University’s new material that consists of forests of carbon nanotubes grown on sheets of graphene, of course!

This graphene/nanotube hybrid is as awesome as it sounds, too; we’re talking about a material that might be the single best electrode interface possible, potentially revolutionizing both energy storage (batteries, supercapacitors) and electronics.

To create the hybrid material, the James Tour Group at Rice University began with a copper substrate coated in a single layer of carbon atoms (graphene). From here, the process is a little bit mystical — it sounds like they place a mixture of aluminium oxide and an “iron catalyst” on the graphene, and heat the whole thing in a furnace. Within a few minutes, carbon nanotubes skyscrapers spring up from the graphene.

As you can see in the picture below, we’re quite literally talking about a sheet of graphene with carbon nanotubes growing upwards from it — up to a distance of 120 microns (0.12mm), which is really rather impressive at this scale. If we scaled it up to actual trees, they would rise into outer space. As you can see in the image at the top of the story, the carbon nanotube forest is also very dense. The most important thing, though, is that the bonds between the graphene and nanotubes are completely seamless — as far as electrons are concerned, there is absolutely no resistance when transitioning between graphene and nanotube.

Why is this important? Because this hybrid material has a ridiculously vast surface area: A single gram of the new material has a surface area of 2,000 square meters (21,500 sq ft) — half an acre of the most conductive material in the world. When it comes to energy storage, there is a direct correlation between energy density and the surface area of the electrodes — this new graphene/nanotube hybrid could result in significantly smaller batteries, or larger batteries that can do more work. In testing, Rice University created a supercapacitor with the new material that matches “the best carbon-based supercapacitors that have ever been made,” which is impressive because “we’re not really a supercapacitor lab, and still we were able to match the performance because of the quality of the electrode.”

Moving forward, the next step for advances such as this is production of the new material in commercial quantities. In all likelihood, the research baton will now pass to commercial companies, such as Intel, Sony, or Samsung, who will try to develop real components and batteries using the graphene/carbon nanotube hybrid material.

Now read: IBM creates breathing, high-density, light-weight lithium-air battery

Research paper: doi:10.1038/ncomms2234 – “A seamless three-dimensional carbon nanotube graphene hybrid material”

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MIT creates carbon nanotube pencil, doodles some electronic circuits

A team of MIT chemists have created a carbon nanotube “lead” that can be used to draw freehand electronic circuits using a standard, mechanical pencil.

In a normal pencil, the lead is usually fashioned out of graphite and a clay binder. Graphite, as you may already know, is a form of carbon that is made up of layer after layer of the wonder material graphene. When you write or draw with a graphite pencil, a mixture of tiny graphene flakes and clay are deposited on the paper, creating a mark. (Incidentally, pencil leads never contained lead; it’s just that when graphite was first used in the 1500s, they thought it was lead ore, and the name stuck).

With MIT’s carbon nanotube pencil, the lead is formed by compressing single-walled carbon nanotubes (SWCNT), until you have a substance that looks and behaves very similarly to graphite. The difference, though, is that drawing with MIT’s pencil actually deposits whole carbon nanotubes on paper — and carbon nanotubes have some rather exciting properties.

In this case, MIT is utilizing the fact that SWCNTs are very electrically conductive — and that this conductivity can be massively altered by the introduction of just a few other atoms, namely ammonia.

In the picture above, electricity is applied to the gold electrodes (which are imprinted in the paper). The carbon nanotube pencil is used to fill in the gaps, and effectively acts as a resistor. When ammonia gas is present, the conductivity of the nanotubes decreases, and thus resistance increases — which can be easily measured. Carbon nanotubes are so sensitive that MIT’s hand-drawn sensor can detect concentrations of ammonia as low as 0.5 parts per million (ppm).

There are two main takeaways here. The first is that MIT has found a form of carbon nanotubes that is stable, safe, and cheap to produce. Second, carbon nanotubes have been used in sensors before, but usually the process involves dissolving SWCNTs in solvents, which can be dangerous. Here, creating a carbon nanotube sensor is as simple as drawing on a piece of paper — either by a human, or an automated process.

The team will now work on other carbon nanotube leads that can be used to detect other gases, such as ethylene (produced by fruit as it ripens) and sulfur (for detecting natural gas leaks). It’s also worth noting that the research was partly funded by the US Army/MIT Institute for Soldier Nanotechnologies — so it wouldn’t be surprising if military personnel are eventually outfitted with these sensors… or perhaps their very own carbon nanotube pencil, for MacGyver-like sensor fabrication in the field.

Now read: Hype-kill: Graphene is awesome, but a very long way from replacing silicon

Research paper: DOI: 10.1002/anie.201206069

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Report measures toxicity levels in phones, iPhone 5 much safer than 2G

Electronics manufacturers are fond of touting the ecological friendliness of their products, but objective attempts to measure the impact of such changes are few and far between. A new report from HealthyStuff.org aims to improve user visibility on this issue. The organization teamed up with iFixit to compare toxic chemical levels in 36 cell phones from Motorola, Samsung, RIM, Apple, LG, Nokia, and Palm.

The phones were evaluated using X-ray fluorescence spectrometry (XRF). High-powered X-rays are fired at the surface to be tested. This causes the material to fluoresce. The light emission of the surface can then be measured, and chemical composition determined. The study measured the chemical composition of a cell phone’s buttons, case, circuit board components, processors, screen, and solder. Not all elements were weighted equally; HealthyStuff defined five elements as primary elements (bromine, chlorine, lead, mercury, and cadmium) and six secondary elements (chromium, cobalt, nickel, copper, tin, and antimony. Secondary elements were not considered as toxic as the primaries and were weighted accordingly.

Here’s the table of results, according to Healthystuff’s weighting:

Over at iFixit, Kyle Wiens noted that if you graph the data set by release date, we see an encouraging trend: 2010 phones, on average, were considerably more toxic than their 2012 counterparts. The iPhone’s chemical composition has changed dramatically in the five years since it was introduced; the 2G’s 5.0 rating is the worst of any phone. Every iPhone since improved on this result, and the iPhone 5 is near the top of the pack. Apple touts its improvements in manufacturing and recycling, although the release of the Retina Display MacBook Pro early last summer sparked a bit of controversy.

What the data also shows, however, is the futility of myopically focusing on cell phone toxicity as a benchmark of improvement. In 2009, only 8% of cell phones were recycled. All too often, “recycled” is a euphemism for “shipped to China.” The small town of Guiyu has become the symbol of what happens when recycling is outsourced to open-air acid baths, burn piles, and garbage heaps. After ten years of serving as the unofficial e-waste capital of the world, Guiyu’s water is undrinkable. Heavy metals and other poisonous compounds are present at multiple orders of magnitude above safety limits, and some 88% of the local children are affected by lead poisoning.

The reason this matters is highlighted in the very first “Finding” that HealthyStuff.org presents. “100% of cell phones tested contain chemical hazards”. That’s true, and it’s going to stay true. Some elements, like lead, can probably be eliminated. Others, like copper, simply can’t be. Copper is ubiquitous in the semiconductor industry precisely because it offers the best combination of conductivity and cost. Silver is very slightly better, but significantly more expensive, prone to corrosion, and also poisonous.

Building devices that rely less on poisonous compounds is still a good idea, but recapturing devices and processing them properly is arguably even more important. With smartphone use skyrocketinng around the world, the only way to prevent long-term damage is to ensure that fewer products end up buried, burned, or bathed in open air acid baths.

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Scientists planning $1 billion mission to drill into the Earth’s mantle

Deep below the our feet, past the thin crust of our planet, lies the mantle. Despite making up the vast majority of the Earth’s mass, we know very little about the composition of this region. What could be there? Mole-men? Crab people? Probably nothing so fanciful, but a team of international researchers are about to find out. At an estimated cost of $1 billion, geologists headed by the Integrated Ocean Drilling Program (IODP) are preparing to start drilling into the mantle for the first time.

The mantle is a 3000 km thick layer of super-heated, mostly solid, rock that fills the space between the human-dominated crust, and the dense iron-rich core. It is believed that knowing more about the makeup of the mantle could have significant impact on our understanding of the origins and nature of Earth. Everything from seismology to climatology and plate tectonics could be affected.

This isn’t going to be an afternoon excursion to the drilling rig, though. It’s going to take a long time to reach the mantle, which is a minimum of 6 km beneath the crust under the best conditions. After considering various methods, researchers have decided to drill through the crust in the Pacific Ccean, which is the only place the 6 km figure holds true. On dry land the crust can be ten times thicker.

To reach the mantle, scientists will be using a custom-built Japanese drilling rig called Chikyu. The Chikyu was first launched in 2002, and is capable of carrying 10 km of drilling pipes. The team is going to need most of that to get down the the seabed and through to the mantle. The Chikyu holds the current deep sea drilling record, having made it 2.2km into the seafloor. This will be a much greater challenge.

The goal is impressive all on its own, but it isn’t until you look at the logistics of making it all work that you realize what a monumental undertaking this is. The high-tech drill bits being used to bore down into the crust only have an active lifespan of 50-60 hours. After that, the team will have to back out of the hole, change the bit, and plunge back down to the murky depths. To top it off, the borehole is only a 30 cm across… and at the bottom of the sea.

One researcher involved in the project, Damon Teagle, described this procedure as trying to align a steel tube the width of a human hair with a 1/10mm hole when it’s at the bottom of a swimming pool. Certainly accomplishments like the Curiosity/MSL landing are an example of great science, but here we have some amazingly precise science happening right on Earth.

With the technology available today, researchers at the IODP believe that it will take years to reach the mantle. It’s going to be time consuming to change out those drill bits every few days. Teagle suspects that the project could get underway within the next few years. Barring a significant advancement in drilling technology, we should get our first samples from the mantle in the early 2020s.

This project might not have the sexiness of landing a rover on Mars, but it has the potential to vastly increase our knowledge about the evolution and fate of our planet. For the time being it’s the only one we’ve got, so that’s important knowledge to have.

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How a Philips light bulb uses blue LEDs to produce white light

Figure it out yet? Any idea what’s going on in the image above? Here’s a hint: that’s a Philips LED bulb in action.

There’s no two ways around it: many potential buyers have been turned off by the yellow cap pieces on some LED bulbs. These bulbs might be efficient, increasingly affordable, and last for upwards of 25,000 hours, but what the heck is with that day glow yellow?

Those three yellow pieces on the top of certain LED bulbs are the remote phosphor… and they are not there just because some misguided designer thought they looked cool. These are a crucial part of the design for one reason, which the image above makes abundantly clear: the bulb uses blue LEDs. What the remote phosphor does is convert that blue light to a shade that is more acceptable to what we expect from indoor lighting. In this case it’s 2700K, or warm yellow.

So, as you probably guessed by now, the image shows a bulb that is missing one of its remote phosphor panels. The phosphors that are in place are doing exactly what phosphors do — emit light through the process of luminescence. What this means, functionally, is that the yellow pieces get the blue light and convert it into exactly the shade of light that Philips is looking for.

As for the “remote” part, that just means that the phosphor is not connected to or built into the LEDs. This is done for a number of design reasons, including the placement of the highly directional LEDs and to prevent multiple shadows from forming.

When one of the yellow pieces is removed — be careful of your eyes if you try it at home — you can clearly see that the light from that third of the bulb is a sort of royal blue. The rest of the light goes through the phosphor and is emitted as a shade of white.

And those neon yellow plastic pieces? When the bulb is on you can’t see them at all, which is why the remote phosphor isn’t as big of a problem as you might think when seeing a bulb on the shelf.

As you can see in the smaller image, Philips’ AmbientLED uses three sets of six blue LEDs, plus the remote phosphor, to generate its light. The company’s LED Prize bulb, in order to take efficiency to the next level, uses a different mix. That bulb uses three red LEDs, two blue, and then another shade of blue. It’s a more complex operation but it helps the L Prize winner get to an excellent 94 lumens per watt, where the normal model gets about 65.

And why use blue LEDs at all? Why not just use LEDs that produce a color that we like? This gets pretty complex, but basically it comes down to something predictable: blue LEDs are more efficient than other colors.

If you were interested in this post, you might want to check out my book, LED Lighting: A Primer to Lighting the Future. It’s available from O’Reilly (DRM-free), Amazon, iBooks, and others.

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Nanocellulose: A cheap, conductive, stronger-than-Kevlar wonder material made from wood pulp

What’s brown and sticky, lightweight, flexible, stronger than steel, stiffer than Kevlar, and conducts electricity? Nanocellulose. Oh, isn’t actually brown and sticky either: it’s transparent.

Nanocellulose is a new wonder material that is simply plant matter that has been carefully smashed to pieces, and then reformed into neatly-woven nanoscale crystals and fibers. You generally start with wood pulp, remove any non-cellulose impurities (such as lignin) using a homogenizer, and then gently beat the mixture to separate each of the cellulose fibers. Depending on the exact process used, these fibers then form into a thick paste (pictured above) of needle-like crystals (2nm wide, hundreds of nanometers long, below left), or a spaghetti-like structure of cellulose fibrils (below right).

This paste can then be shaped, or used to laminate other surfaces — and when it dries, it has amazing properties. Nanocellulose is very similar to glass fiber or Kevlar — it’s very stiff, lightweight, and it has eight times the tensile strength of steel. The crystalline form of nanocellulose is transparent, too — and perhaps most importantly, unlike other wonder materials such as graphene, nanocellulose can be produced in large quantities very cheaply. In crystalline form, nanocellulose is gas impermeable — and when used as the basis for foams/aerogels, it’s highly absorbent.

In July, the US Forest Service opened the country’s first nanocellulose plant in Madison, Wisconsin. This is only the third nanocellulose plant in the world, with the other two being in Canada and Sweden. The CelluForce factory in Montreal is now producing a tonne of nanocellulose per day. After a ramping-up period of a couple of years, the US Forest Service expects to sell nanocellulose for just a few dollars per kilo.

Just so you have some idea of the industries that could be affected by nanocellulose, this is a list of who sent representatives to the opening of the Madison plant: IBM, Ecolab, Lockheed Martin, numerous companies from the pulp/paper industries, and various universities. The Department of Defense is also interested, as are automotive and medical device industries.

As far as electronics are concerned, IBM is probably eyeing up nanocellulose for use in flexible OLED displays, which it has been researching for the last few years. The DoD is thinking about new lightweight armor, and automotive/aerospace are no doubt interested in nanocellulose as a cheaper alternative to glass and carbon fiber. The pulp/paper industries are eyeing up nanocellulose as a way of reinforcing products or increasing absorbency (kitchen towels, tampons, etc.)

Our use of nanocellulose is likely to accelerate very quickly. Its safety — both during production, and in final products — has already been proven. Nanocellulose is so safe that it could even be used as a low-calorie food thickener (it is just concentrated plant matter, after all). For more uses of nanocellulose (there are lots), hit up Wikipedia.

Read more about graphene, and silicene — two more wonder materials

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