Add a dash of titanium dioxide for self-cleaning walls, displays and garden furniture

A plastic garden furniture armrest without (left) and with (right) a self-cleaning photocatalytic coating

For many people, the onset of warmer weather can mean pulling out the ol' scrubbing brush and getting to work on the slimy film of moss, algae, fungi and bacteria that has built up on the garden furniture over the colder months. But we may soon be able to say goodbye to this tiresome chore thanks to researchers at Fraunhofer who are developing coatings that would be activated by the sun’s rays to destroy organic substances attaching themselves to various surfaces.
The photocatalytic coatings being developed at the Fraunhofer Institute for Thin Films and Surface Engineering (IST) incorporate titanium dioxide molecules that are "activated" by the UV light in the sun’s rays to produce free radicals in an electrochemical reaction. These free radical molecules destroy the cell walls of bacteria, fungi and similar organisms before penetrating the cytoplasm and damaging the organism’s DNA.
The Fraunhofer researchers set out to discover just what kind of organic elements these photocatalytic coatings were effective against. Dr. Iris Trick, group manager at the Fraunhofer Institute for Interfacial Engineering and Biotechnology (IGB) in Stuttgart ran outdoor tests on plastic garden chair armrests with and without the coating.
They first sprayed the coated and uncoated armrests with a mixture of various bacteria, mosses, algae and fungi and then left them exposed to the weather for two years. After this period the team says it was almost impossible to remove the layer of dirt from the uncoated armrests, while the coated armrests remained almost completely clean and white.
In the lab, the researchers also tested the effectiveness of the coatings on a range of other surfaces. They applied up to 30 different kinds of fungal, bacterial and algal cultures to coated and uncoated surfaces and compared how they evolved. The results indicated the potential applications for the photocatalytic coatings extend far beyond garden furniture armrests.
Ten Fraunhofer Institutes have now joined forces to form the Fraunhofer Photocatalysis Alliance to explore various avenues for the technology.
One team is looking to put titanium dioxide molecules to work in paints that could be applied to building facades that would stay reasonably clean when exposed to sunlight. Another team has developed a self-cleaning coating for glass surfaces that could be used on displays, such as smartphone screens.
"If you apply a thin coating of titanium dioxide to a glass surface such as a smartphone screen, the skin oils and fingerprints gradually disappear from the display by themselves," says Dr. Michael Vergöhl, head of department at the Fraunhofer IST.
Unlike previous photocatalytic surfaces that would need to sit in the sun for up to three days to work their self-cleaning magic, the new coating only requires one hour of sunlight. The researchers say the next step is to develop materials that can also be activated by artificial light.
Source: Fraunhofer

Electrochemical flow capacitor: Hybrid battery-supercapacitor design targets grid storage

Drexel University research combining the best features of batteries and supercapacitors could lead to a more stable, greener energy grid

Researchers at Drexel University are developing an electrochemical flow capacitor (EFC) that combines the storage capabilities of batteries with the much longer cycle life and power output of supercapacitors. The team's goal is to improve the stability of the energy grid and ease the integration of renewable energy sources.
Renewables such as wind and solar power are experiencing an exponential year-by-year growth, but integrating such an intermittent and unpredictable power source into the grid can be problematic as it calls for a highly flexible, cost-effective solution that can store vast amounts of energy and release it quickly whenever needed.
While batteries can store large amounts of energy, they cannot dispense it quickly and they can only survive about one thousand charge-discharge cycles. Conversely, supercapacitors can release energy in quick bursts and last for hundreds of thousands of cycles, but they can't store quite as much energy. Recent advances in both battery and capacitor technology have been working toward a perfect marriage of the two.
The EFCs developed at Drexel University are another step in this direction and are aimed at large scale usage. The device consists of a cell connected to two external reservoirs, each containing a mixture of electrolyte liquid and charge-carrying carbon particles. The uncharged slurry is pumped from the reservoir tanks into the flow cell, where the stored energy is transferred to the carbon particles. Once charged, the slurry can be stored in large tanks until the energy is needed, at which time the entire process is reversed.

This conceptually simple approach promises to be both scalable and cost-effective: EFCs can survive hundreds of thousands of charge-discharge cycles, their power output is comparatively large - controlled by the size of the electrochemical cell - and their capacity is proportionate to the size of the tanks that contain the carbon-electrolyte slur.
The researchers still need to overcome some challenges, chief among which is the low energy density of the slurry, which currently requires very large tanks for storage. They are now developing new slurry compositions to increase its energy density tenfold which, they believe, would be enough to make this technology practical.
A paper describing this energy storage concept was recently published in the journal Advanced Energy Materials.
Source: Drexel University

Stretchy Bowl saves space, keeps fruit fresher

Stretchy Bowl expands as needed to accommodate more fruit, all of which should stay fresher thanks to the breathable fabric it's made from

We're all encouraged to eat more fresh fruit - whether by parents, partners, or physicians - but it isn't always the easiest advice to follow. Fresh fruit doesn't stay fresh for long, especially if it sits in a bowl with other types of fruit that are closer to being past their best. It's also difficult to know what size of bowl you need to own in order to accommodate the differing numbers and types of fruit you are storing at any one time. Stretchy Bowl is an effort to solve both these issues.

Stretchy Bowl comprises an easy-to-assemble white metal base and a round piece of elastic fabric held in place by a metal hoop. The porous fabric sits on top of the base like a trampoline waiting to be weighed down with fruit. As you add individual pieces of fruit it shapes itself correctly to hold the fruit in place. Its maximum capacity is dictated by the curved legs of the base.
The breathable material allows air to circulate more routinely, keeping all sides of the fruit equally exposed. This should prevent one piece of fruit sitting enclosed on all sides and forgotten at the bottom of the bowl from going rotten too quickly and taking the rest of the bowl's fruit down with it.
When the fruit bowl isn't being used it can be flattened down for easy storage or transport. Stretchy Bowl comes in three colors: blue, red, or gray fabric to complement the white base. It is priced at US$59.
Sources: Hook n' Loop Design via NotCot

Silver nanowire conductors could mean better stretchable electronics

A team of scientists have created elastic conductors using silver nanowires, which are said to offer several advantages over other materials used in the past

Earlier this year, a team led by North Carolina State University’s Dr. Yong Zhu reported success in creating elastic conductors made from carbon nanotubes. Such conductors could be used in stretchable electronics, which could in turn find use in things like bendable displays, smart fabrics, or even touch-sensitive robot skin. Now, he has made some more elastic conductors, but this time using silver nanowires – according to Zhu, they offer some big advantages over carbon nanotubes.

“Ag [silver] nanowires (NWs) have higher conductivity that carbon nanotubes (CNTs) or other metal nanowires,” he told us. “As such, the conductivity of AgNW stretchable conductor in our case is higher than other CNT based stretchable conductors.”

Additionally, silver nanowires should lend themselves more towards mass production. “AgNWs are chemically synthesized in solution, which makes them easily compatible with existing parallel or serial fabrication/patterning techniques,” he said. “CNTs are grown on substrate by dry methods and extra steps are required to disperse them in solution for printing.”

Finally, he added, AgNWs are biocompatible. This means they could safely be used in stretchable biomedical electronic devices. By contrast, he stated that “unrefined CNTs possess some degree of toxicity.”

The silver nanowire-based conductors are fabricated using a fairly simple technique.

First, the nanowires are laid on a silicon plate. A liquid polymer is then poured over them and heated, which causes it to convert from a liquid to an elastic solid form. It is subsequently peeled off the silicon, with the nanowires now sealed inside of it – some previous attempts at stretchable electronics have involved the conductive material being deposited on the outside of the substrate, from which it could possibly delaminate over time.

When the polymer sheet is stretched for the first time, the surface of the side containing the wires relaxes back into a buckled, wavy form. Every time it’s stretched after that, it can be elongated by up to 50 percent without any detrimental effect on the nanowires’ conductivity. This is because the buckling allows the wires to stay in a fixed position relative to one another, regardless of whether the polymer is in a stretched or relaxed state.

A paper on the research was recently published in the journal Advanced Materials.

Source: North Carolina State University

CryoSolplus could help keep EV batteries cool

A sample of Fraunhofer's CryoSolplus phase-change battery coolant

One of the big enemies of electric vehicle batteries is heat. Batteries already warm up under normal use, but when hot summer temperatures or high workloads are thrown in, overheating becomes a real possibility. According to the Fraunhofer Institute for Environmental, Safety and Energy Technology, running a battery at ten degrees over its maximum “comfort level” of about 35ºC (95ºF) can deplete its service life by half. That’s why researchers there have developed a battery coolant known as CryoSolplus, which is said to offer three times the cooling capacity of plain water.

CryoSolplus consists of water, paraffin, stabilizing tensides (detergents) and “a dash” of glycol anti-freeze. When the solution is cool, the paraffin takes the form of solid droplets. The tensides keep those droplets suspended uniformly throughout the mixture, as opposed to clumping together or floating on top.

As the solution is heated, the droplets melt, storing the heat in the process. Circulated in pipes around EV batteries, CryoSolplus could utilize this process to continuously carry away battery-generated heat. The liquified paraffin forms back into droplets as the solution cools, ready to repeat the process on the next drive.

The even dispersion of the droplets is key to the coolant’s effectiveness, so the researchers had to make sure that the tensides they chose could be stored for a long time without deteriorating, that they could stand up to the rigors of being pumped through pipes, and that thermal stresses (such as freezing and thawing) wouldn’t affect their performance.

Because CryoSolplus conducts heat so much better than water, less liquid would be needed within a vehicle’s cooling system, resulting in a smaller coolant tank size and lower weight. It is estimated that a system using the coolant would only be about €50 to €100 (US$61- $122) more expensive than a water-based cooling system.

The company is now working on boosting the coolant’s heat capacity, along with its ability to transfer heat and flow more smoothly. Field tests using an experimental vehicle are being planned.

Source: Fraunhofer

New catalyst could replace platinum to bring down the cost of microbial fuel cells

University of Wisconsin researchers discover nannorod catalyst that works as well as platinum in generating hydrogen at a fraction of the cos

University of Wisconsin-Milwaukee (UWM) researchers have identified an inexpensive nanorod catalyst with efficiencies rivaling that of platinum. Composed of nitrogen-enriched iron-carbon nanorods, the new catalyst holds the promise of cheaper, more efficient microbial fuel cells (MFCs) that generate their own hydrogen from waste water.

The hydrogen fuel cell is the holy grail of green energy. It burns hydrogen and gives off nothing but water. What could be more environmentally friendly than that? The problem is, hydrogen isn’t just lying about in the ground like oil or natural gas. True, it’s the most abundant element in the universe, but on Earth all of it is locked up in water and other chemicals. To be used as an energy source, the hydrogen has to be extracted and, unfortunately, the main source of most commercial hydrogen today comes from fossil fuels – which sort of defeats the purpose.

One alternative is microbial fuel cells, which use microorganisms to break down waste water into hydrogen and oxygen. That’s a step in the right direction, but there’s still a snag. To reach practical efficiency, an MFC needs a catalyst to goose along one of the chemical reactions involved in the process. That catalyst is usually platinum, which does its job very well, but is also extremely expensive at over US$1,200 per ounce. It also doesn’t help that platinum, like many catalysts, is susceptible to poisoning by impurities coating its surface, resulting in a very pricey replacement job.

In contrast, the UWM nanorod catalyst is composed of cheap, common elements. It consists of nitrogen bonded to the surface of a carbon rod with a core of iron carbide. According to the UWM researchers, this structure is optimal for electron transport. The upshot is that over three months of testing, the new catalyst demonstrated consistent performance that was superior to platinum and has every indication of being stable and scalable. More importantly, it’s much more economical. Platinum makes up 60 percent of the cost of an MFC and with the UMW catalyst only five percent the cost of a platinum catalyst, the savings are obvious.

According to nanorod creator Professor Junhong Chen,“fuel cells are capable of directly converting fuel into electricity. With fuel cells, electrical power from renewable energy sources can be delivered where and when required, cleanly, efficiently and sustainably.” With a view toward making the UMW catalyst practical, Professor Chen and his team are now concentrating on studying the exact characteristics of the catalyst and making it suitable for mass production.

Source: UWM

Harvard scientists create hydrogen fuel cell that lasts longer

Harvard researchers have developed a solid-oxide fuel cell that doubles as a battery

Materials scientists at Harvard have created a fuel cell that not only produces energy but also stores it, opening up new possibilities in hydrogen fuel cell technologies. The solid-oxide fuel cell (SOFC) converts hydrogen into electricity, and could have an impact on small-scale portable energy applications.

The thin-film SOFC benefited from recent advances in low-temperature operations, which enabled the integration of versatile materials, said lead researcher Shriram Ramantham. The star of the new cell is vanadium oxide, a multifuncional material that allows the fuel cell to multitask as both an energy generator and storage medium.

The new fuel cell uses a bilayer of platinum and vanadium oxide for the anode, which allows the cell to continue operating without fuel for up to 14 times as long as the thin-film SOFCs that use platinum only for the electrodes. In the case of the latter, when the platinum-anode SOFC runs out of fuel, it will continue to generate power for only about 15 seconds before it fizzles out. With the new fuel cell, the scientists have managed to increase that to three minutes, 30 seconds at a current density of 0.2 mA/cm2.

That length of time could be increased with further improvements to the composition of the vanadium oxide-platinum anode. It should happen fairly soon, and this type of fuel cell could be available for applications testing within two years. The researchers say that one field that could benefit from the new fuel cell is micro aerial vehicles, although fuel cells for powering vehicles are already a reality.

The researchers observed and confirmed a few chemical phenomena that possibly explains the extended power of the cell. The first of these is the oxidation of the vanadium ions. Another one is the storage of hydrogen within the vanadium oxide crystal lattice, which is then gradually released and oxidized at the anode. Finally, they noticed that the concentration of oxygen ions differs from the anode to the cathode, which could mean oxygen anions (negatively-charged ions) also get oxidized as in a concentration cell.

Details about the research appeared in the journal Nano Letters.

Source: Harvard University

New MIT chip harvests energy from three sources

MIT doctoral student Saurav Bandyopadhyay has designed a new chip capable of harvesting energy from three ambient sources

The problem with depending on one source of power in the drive toward the battery-free operation of small biomedical devices, remote sensors and out-of-the-way gauges is that if the source is intermittent, not strong enough or runs out altogether, the device can stop working. A small MIT research team has developed a low-power chip design capable of simultaneously drawing power from photovoltaic, thermoelectric, and piezoelectric energy sources. The design also features novel dual-path architecture that allows it to run from either onboard energy storage or direct from its multiple power sources.

Previous research projects at the lab of MIT's Head of the Department of Electrical Engineering and Computer Science, Prof. Anantha Chandrakasan, have led to developments of super-low-power wireless communication and computer chips that have their power needs satisfied by either natural light, heat or vibrations. According to its designer, doctoral student Saurav Bandyopadhyay, the new energy combining circuit is capable of using all three ambient power sources at the same time.

Bandyopadhyay says that each source typically requires its own control circuit to meet its specific needs - thermal sources might only produce between 0.02 and 0.15 volts, low power PV cells can offer up to 0.7 volts and circuits can expect anything up to five volts from vibration harvesters. He points out that most efforts to draw power from multiple source have so far concentrated on simply switching between them, depending on which one is providing the most juice at any given moment.

For example, a sensor might initially get its power from a light source, which could then be abruptly cut off in favor of a piezoelectric harvester, then when the rumble dies down a thermal system might kick in. Rather than waste the energy available from blocked-off sources, the new design allows all three power sources to contribute by rapidly and continuously switching between them to harvest energy from multiple sources (almost) simultaneously.

The researcher has also optimized the control circuits to maximize the amount of power available to devices. Like other designs, the new chip routes energy to an onboard storage medium such as a battery or supercapacitor. Bandyopadhyay claims his development also allows the device to be powered directly from multiple sources, giving it the potential to bypass the storage system altogether.

The new design is claimed to result in 11 - 13 percent efficiency gains over the traditional two-stage approach, and be capable of handling input voltages from 20mV to 5V.

A paper entitled "Platform Architecture for Solar, Thermal, and Vibration Energy Combining With MPPT and Single Inductor" will shortly be published in the IEEE Journal of Solid-State Circuits. The project was funded by a collaboration of defense/semiconductor companies and DARPA.

Source: MIT via Inhabitat

Cost-effective solar power module could also serve as an eco-friendly furnace

A dish-shaped mirror focuses sunlight onto a glass ball, which distributes it evenly onto an array of photovoltaic cells

Borrowing technology from sophisticated telescope mirrors as well as high-efficiency solar cells used for space exploration, a group of students and researchers at the University of Arizona is putting the final touches on a novel power plant that promises to generate renewable energy twice as efficiently as standard solar panel technology with highly competitive costs and a very small environmental impact.

Curved mirrors in solar power plants usually concentrate the sun's rays along a water pipe, heating the water into steam that is then fed to power-generating turbines. But rather than distributing the power over the area of a water pipe, researchers at the University of Arizona are working on focusing as much as possible of the sun's captured energy onto a precise point in space.

The target is a small glass ball that is only five inches in diameter. The ball contains a specially coated lens that redirects the light to an array of 36 small, high-efficiency solar cells, which were originally developed for space applications, that can absorb light over a broader spectrum than standard cells. And instead of mirrors shaped like a cylinder, the team had to develop dish-shaped mirrors that focus light onto a point.

Regents' Professor Roger Angel has pioneered a new way to make glass mirrors to concentrate sunlight to make electricity (Photo: Patrick McArdle/UAnews)

"By using mirrors to focus on small but super-efficient photovoltaic cells, we have the potential to make twice as much electricity as even the best photovoltaic panels," Prof. Roger Angel, who is coordinating the research efforts, commented.

Because the rays concentrate on a small area, the process generates very high temperatures – so high, in fact, that they could melt the solar cells in seconds. To prevent this, the team designed an effective cooling system, a simple combination of fans and radiators that keeps the solar cells within 36° F (20° C) of the ambient air temperature.

Each module features two highly reflective, curved, 10 by 10 feet (3 x 3 m) glass mirrors mounted on a steel structure. The module automatically orients itself toward the sun for maximum performance: in the morning it turns to the east, tracks the sun's path for the entire day and, after sunset, predicts where the sun will be rising and preps itself for the next day of clean, efficient power generation.

The "tracker" consists of a steel frame that ultimately will support eight mirrors, together generating enough electricity to power about four to five homes (Photo: Blake Coughenour/UA)

A prototype with only two mirrors was shown to generate 2.5 kilowatts of electricity – enough to meet the demand of two average U.S. households – but the team plans to place eight mirrors on each module.

The manufacturing process for the dish-shaped mirrors is going to be optimized for mass production to reduce costs. The materials used are relatively cheap and, because no water is required to generate power, the plant's environmental footprint would be smaller than that of a conventional solar panel-based plant.

"Our technology holds the promise of getting the price of solar energy down to where it can be used on a large scale without depending on subsidies and be competitive in the electricity market," Angel commented. He says that an array of sun trackers on an area measuring about seven by seven miles (11 x 11 km) would generate 10 GW of power during sunshine hours – as much as a big nuclear power plant – and suggests that the system could be deployed in deserts for maximum effect.

The researchers have already patented their process for manufacturing their curved, highly reflective glass mirrors, and the team is now looking to find new applications for this technology.

One promising prospect, which would require little adaptation, would be to explore the thermal properties of the modules. Because the temperatures achieved are so high, Angel's team plans to adapt their system into a novel, eco-friendly furnace that can melt glass within seconds. The researchers were recently awarded a US$1.5 million grant by the Department of Energy to investigate just such a possibility.

The video below illustrates some of the challenges the team faced in developing their system.

Source: University of Arizona

Ultra-efficient 4,000 mph vacuum-tube trains – why aren't they being built?

Terraspan's giant, 4,000 mph (6,437 km/h) vacuum tube train, which also doubles as a superconducting power line.

In the 1800s, when pneumatic tubes shot telegrams and small items all around buildings and sometimes small cities, the future of mass transit seemed clear: we'd be firing people around through these sealed tubes at high speeds. And it turns out we've got the technology to do that today – mag-lev rail lines remove all rolling friction from the energy equation for a train, and accelerating them through a vacuum tunnel can eliminate wind resistance to the point where it's theoretically possible to reach blistering speeds over 4,000 mph (6,437 km/h) using a fraction of the energy an airliner uses – and recapturing a lot of that energy upon deceleration. Ultra-fast, high efficiency ground transport is technologically within reach – so why isn't anybody building it?

The next frontier of speed

Vacuum tube-based transport has a lot of things going for it. Speed, for one. Anyone who has spent time on a fast motorcycle knows that even without any wind, the air itself is a brutally powerful force working against your engine as you get up above 125 mph (200 km/h). In fact, air resistance is the number one problem to combat as speeds increase. Airliners have to fly 40,000 feet up in the air to take advantage of the reduced drag you get when the air thins out a bit. And even with this advantage, they still can't cruise much faster than 570 mph (917 km/h) without being horribly inefficient.

Take air resistance and rolling resistance away by operating in a vacuum and magnetically levitating your vehicle, and you're eliminating the biggest two hurdles to achieving extremely high speeds. And once you reach your top speed, you simply stop accelerating, apply no further energy, and coast. You lose very little speed until you reach your destination, at which point you can slow your vehicle down electromagnetically and recapture almost all the energy you put in to speed it up.

Theoretically, with the right length of vacuum tube set up, you could zoom all the way around the world in a matter of hours, nearly ten times faster than today's airliners. Operating in a vacuum, these vehicles would make almost no sound, even as they smashed through the sound barrier, because there'd be no air for them to create sonic vibrations in. With no actual points of contact or friction with the track or tube, there would be virtually no energy lost to heat dissipation.

The vacuum-tube revolutionaries

There are no shortage of people and groups pushing for widespread adoption of vacuum tube technology as a superfast travel option – after all, with the demise of the Concorde supersonic airliner, mass global transit speeds have remained stagnant since the 1960s. Sending an e-mail from London to Beijing might be instantaneous, but the rest of the world still feels like a long way away if you have to physically travel around it.

We recently wrote about the ET3 consortium, a licensing organization that owns a number of patents in the evacuated tube transport space, Acabion's vacuum tube streamliners, and the gigantic Startram space elevator project, which would make use of the low energy requirements of the vacuum tube maglev idea to cheaply propel various objects into orbit.

Another contender with an interesting take on the technology is Terraspan, a group that wants to combine superfast transport with the creation of a new intracontinental power grid that can make much more efficient use of the cycles of power creation and usage across a large country like the United States.

Here's the plan – for step one, Terraspan would like to build a backbone network of underground vacuum tube train tunnels linking eastern Canada to western Mexico through the United States. Embedded in the train tunnel network would be a series of thick, superconducting energy cables that would form the heart of the first true continental power grid.

The benefits of a long-distance power grid are simple – you can take the energy produced by solar and wind producers in the arid central areas of America, and make it available to much more densely populated and power-hungry areas on the eastern and western coasts. You could also make more efficient use of power creation and usage cycles – energy that's created in California at off-peak times can be sent across the grid to be used in peak hour in New York.

So here's a plan that wraps up super-fast, ultra-efficient, convenient transport with smart energy usage and a tangible boost for renewable power creation schemes. Let's go, right?

The case for the negative

Of course, if it was that simple, we'd already be blasting around the Earth at orbital speeds like they were predicting in the 1800s. Turns out there's a few serious roadblocks in the way.

Safety is no small concern when you're talking about speeds in excess of 4,000 mph (6,437 km/h). After all, we've all seen the wreckage that can be caused in a 60 mph (96 km/h) car crash. The kinds of tube tracks we're talking about here would have to stretch thousands of miles in order to reach their optimum level of benefit – that's thousands of miles of safety risks. What happens when an earthquake strikes and cracks the pressure seal or destroys the tube completely? A vehicle traveling 4,000 mph is going to eat up some serious distance in an emergency stop situation.

What's more, there's really very little precedent to show exactly what happens when a populated carriage goes from ultra high speed in a vacuum to being struck with regular air pressure. Terraspan's website details a plan to shape the trains with a sort of air wing to bring them down gently in the case of pressurization, but one can easily imagine that being battered to death at the top of the tunnel would be just as bad as crashing to your doom at the bottom of it. How can you hope to control a 4,000 mph airfoil within a tiny tube when the air pressure onset is sudden and unexpected?

The thing about maintaining a total vacuum is that one hole in your structure compromises the vacuum almost immediately. And it's not hard to dream up a dozen situations, whether natural disasters, man-made errors in judgement or acts of war or terrorism that could easily crack or break a structure like this.

Then again, let's say these safety issues can be adequately addressed. Perhaps the more pressing obstacle – at least for the time being – is a purely economical one. Mag-lev train lines themselves are exorbitantly expensive: Japan's Linimo HSST, a low-speed suburban mag-lev line, cost around US$100 million per kilometer (0.62 miles) to build. And while China hopes to get away with only US$18 million per kilometer when it extends its high speed Shanghai demonstration line, neither of these trains require air-tight tunnels.

Add to this the hidden cost of maintaining the vacuum (presumably by constantly pumping air particles out of thousands upon thousands of miles of vacuum tube) and you're left with a very costly proposition. And that's not to mention land acquisition – which could prove tough, as these machines move so fast that their turning radius is gigantic and route choices will be limited.

So where is vacuum-tube transport likely to go in the next few decades? It's hard to say – although it seems extremely unlikely that a cash-strapped United States or European Union member would be willing to pony up and lead the way.

Note: edited for correct physics - thanks guys, you can always rely on Gizmag commenters to keep our facts straight!

Two-faced solar cells boost yields by up to 50 percent

Two-faced solar cells boost yields by up to 50 percent

Israeli photovoltaics developer bSolar has developed a double-sided solar cell it claims can boost the energy yields of solar panels by up to 50 percent when installed vertically, or by between 10 and 30 percent in more typical installations. The "bifacial" cells rely on a back surface field (BSF) of boron rather than aluminum, which bSolar claims not only allows for an open rear face but also increases the efficiency at the front of the solar panel.

Back surface fields are effectively a barrier which reduces the electron-electron hole recombination at the surface, enhancing a solar cells overall efficiency. Unlike traditional aluminum BSFs, bSolar's is translucent, allowing more light into the cell.

It makes intuitive sense that a two-faced solar panel (if you'll pardon the expression) installed in an upright position could conceivably boost efficiency by 50 percent, provided both sides a receive the same amount of light.

More interesting is that bSolar claims up to 30 percent higher energy yields in more typical installations, by which it means ground or roof-mounted panels angled roughly perpendicular to the sun. In this scenario, the rear surface of the panel is essentially harvesting bonus light reflected from the ground or roof.

The bonus yield will inevitably be effected by the reflectivity of the surface (so, yet another reason for white rooftops) and the density of surrounding obstructions including other solar panels.

bSolar has struck deals with panel manufacturers including solar AG, asola Solarpower GmbH, Solar-Fabrik AG, SI-Modules GmbH and Solarnova Produktions-und Vertriebs GmbH. It recently announced that panels equipped with its bifacial cells would be used in a 730 kW installation by TSBM in Nasukarasuyama, Japan.

Source: bSolar, via GigaOM

Oxygen microcapsules could save lives when patients can't breathe

A syringe containing the oxygen microparticle solution

Six years ago, Dr. John Khier of Boston Children’s Hospital began investigating the idea of using injectable oxygen on patients whose lungs were incapacitated or whose airways were blocked. He was prompted to do so after a young girl that he was caring for passed away – she succumbed to a brain injury, which resulted when severe pneumonia caused her lungs to stop working properly, which in turn caused her blood oxygen levels to drop too low. Now, Khier is reporting that his team has injected gas-filled microparticles into the bloodstreams of oxygen-deprived lab animals, successfully raising their oxygen levels back to normal levels within seconds.

The microparticles are created using a device called a sonicator, which uses high-frequency sound waves to mix lipids (fatty molecules) and oxygen gas together. This results in the mixture forming into particles about two to four micrometers in diameter, each of which consists of an oxygen core surrounded by a lipid outer shell. Because the particles are so small and flexible, they are able to squeeze through capillaries – by contrast, if straight oxygen gas were injected, bubbles of it could block the blood flow and cause embolisms.

The microparticles are combined with a liquid carrier, so they can then be injected into the bloodstream. That suspension contains three to four times the amount of oxygen as regular red blood cells, so relatively small amounts of it are required, depending on how much of an oxygen level boost is required.

When the microparticle solution was tested on lab animals with blocked tracheas, it was able to keep them alive for up to 15 minutes without their taking a single breath, plus it also reduced low-oxygen-related cardiac arrests and organ injuries.

It is intended that the treatment would be used mainly in emergency response scenarios, to hold non-breathing patients over for 15 to 30 minutes – the carrier liquid would overload the bloodstream if used for longer. Khier and his team envision paramedics, emergency clinicians or intensive care personnel keeping supplies of the microparticle solution close at hand and ready to go, should it be needed.

“This is a short-term oxygen substitute—a way to safely inject oxygen gas to support patients during a critical few minutes,” he said. “Eventually, this could be stored in syringes on every code cart in a hospital, ambulance or transport helicopter to help stabilize patients who are having difficulty breathing.”

Although already-available blood substitutes are capable of carrying oxygen, they still first need to be oxygenated by functioning lungs.

A paper on the research was published this Wednesday in the journal Science Translational Medicine.

Source: Boston Children’s Hospital