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Wednesday, 27 May 2009

How old technologies can learn new tricks, may, 2009

Today:

  1. Batteries grown from 'armour-plated' viruses
  2. Ancient diatoms lead to new technology for solar energy
  3. DNA 'tricked' to act as nano-building blocks
  4. Breathing batteries could store 10 times the energy
  5. Alcohol makes autos more climate-friendly
Short stories:
  1. Solar car aims to put rivals in the shade
  2. Honda Connects Your Brain to a Robot
  3. Five-Dimensional DVD Could Hold Data of 30 Blu-ray Discs

Ok, today it's hard to say which one is a short story and which ins't but I guess the last three are the short stories since they don't have comments. But all of the articles are quite shortened, so don't worry. And they are quite fun too. What's common for all of them? They show a clever new use of an old technolgy with surprising results. Of course, I'm most intruiged by the lithium batteries (and the solar energy), because they are such a pain for every laptop-person on the world.
But it's not only about batteries. It's about cool new engines, cool new cars and cool new robots. I hope you enjoy it, it's an easy read, nothing too dramatic, but yet quite optimistic.

Ancient diatoms lead to new technology for solar energy

April 8th, 2009

Engineers at Oregon State University have discovered a way to use an ancient life form to create one of the newest technologies for solar energy, in systems that may be surprisingly simple to build compared to existing silicon-based solar cells.

The secret: diatoms.

These tiny, single-celled marine life forms have existed for at least 100 million years and are the basis for much of the life in the oceans, but they also have rigid shells that can be used to create order in a natural way at the extraordinarily small level of .

By using biology instead of conventional semiconductor manufacturing approaches, researchers at OSU and Portland State University have created a new way to make "dye-sensitized" , in which photons bounce around like they were in a pinball machine, striking these dyes and producing electricity. This technology may be slightly more expensive than some existing approaches to make dye-sensitized solar cells, but can potentially triple the electrical output.

Dye-sensitized technology, for instance, uses environmentally benign materials and works well in lower light conditions. And the new findings offer advances in manufacturing simplicity and efficiency.

The new system is based on living diatoms, which are extremely small, single-celled algae, which already have shells with the nanostructure that is needed. They are allowed to settle on a transparent conductive glass surface, and then the living organic material is removed, leaving behind the tiny skeletons of the diatoms to form a template.

A biological agent is then used to precipitate soluble titanium into very tiny "nanoparticles" of titanium dioxide, creating a thin film that acts as the semiconductor for the dye-sensitized solar cell device. Steps that had been difficult to accomplish with conventional methods have been made easy through the use of these natural biological systems, using simple and inexpensive materials.

The physics of this process, Rorrer said, are not fully understood - but it clearly works. More so than materials in a simple flat layer, the tiny holes in diatom shells appear to increase the interaction between photons and the dye to promote the conversion of light to electricity, and improve energy production in the process. source

My comment: Ok, that certainly sounds fun! For a moment I was worried that they actually keep the little guys alive on the glass, but it turned out they kill them after all.

Batteries grown from 'armour-plated' viruses

GENETICALLY engineered viruses that assemble into electrodes have been used to make complete miniature rechargeable batteries for the first time. The new lithium ion batteries are as powerful as existing devices but smaller and cleaner to make, claim the team behind the work. The technology could improve the performance of hybrid electric cars and electronic gadgets.

Lithium ion batteries exploit the reactivity of lithium to produce a current. Inside the battery, lithium ions move from the anode to the cathode, forcing electrons in the opposite direction around an external circuit. This process is reversed when the battery is recharged.

Making these batteries takes a tough manufacturing process because of the highly reactive components, aggressive solvents and high temperatures used in construction, as well as the dangers of handling lithium.

Viruses could make this process much safer and cleaner, says Angela Belcher at the Massachusetts Institute of Technology. Her team converted a harmless virus called M13 into a cathode by inserting a gene that causes the virus to produce proteins that bond with iron and phosphate ions in a surrounding solution. As a result, the long, tubular virus particles become sheathed in an "armour plating" of iron phosphate, turning them into nanowires.

The resultant batteries were not as good as commercial models, however - the cathodes turned out to be good at conducting lithium ions but not electrons.

To solve this, the team inserted a second gene that creates a protein at the tip of the virus that bonds to a carbon nanotube. The nanotube increases the electron conductivity of the combined structure.

The resulting battery turned out to be as good as the best commercially available that use crystalline lithium iron phosphate materials . And since the team had previously used the same viral technique to produce anodes it has now been able to make a full virus-based 3-volt lithium ion battery.

Compared to conventional lithium ion batteries, the biologically grown battery is environmentally friendly because much of the materials can now be made at room temperature or on ice and without harsh solvents. ". source

My comment: That is also very cool! If you think about it, this gives a whole new sense of the word "biotechnology". And it really offer a good opportunity for perfecting the technology, since it's already on commercial level. I just hope the viruses inside are safe (ly kept inside forever).

DNA 'tricked' to act as nano-building blocks

April 13th, 2009

(PhysOrg.com) -- McGill researchers have succeeded in finding a new way to manufacture nanotubes, one of the important building blocks of the nanotechnology of the future. Their building material? Biological DNA.

A team of researchers, led by Prof. Hanadi Sleiman in collaboration with Prof. Gonzalo Cosa, both of McGill University's Department of Chemistry, can now tailor different geometries, rigidities and porosities into these nanotubes through the clever introduction of non-DNA molecules. This work is to be reported in the April 13 edition of the journal .

Nanotubes are infinitesimally small, measuring six or seven nanometers across. (A nanometre, one-billionth of a metre, is one ten-thousandth the diameter of a human hair.) One of the important features of these tubes is their extreme length, at about 20,000 nanometres. While they are tiny, they offer an incredibly versatile potential to solve a number of key problems facing nanotechnology researchers. This includes the design of drug delivery vehicles, the manufacture of electronic nanowires, medical implants and scaffolds for solar energy conversion among others.

Nanotechnology's tremendous potential to affect social and economic development is dependent on scientists first being able to make the necessary molecules and materials. To make this happen, nanotechnologists are now using nature's code of life, DNA. With its simple A, T, C and G alphabet, DNA is able to direct the formation of an astounding array of proteins that work collectively to create life. It is precisely this property of chemical information stored in DNA that nanotechnology is now exploiting.

In this case, are programmed to assemble into complex one- two- and three-dimensional structures. By incorporating synthetic molecules into such strands of DNA, the Sleiman group provided nature's workhorse with further specific dialed-in structural and functional properties.

Using this method, Faisal Aldaye, Peggy Lo, Pierre Karam and Chris McLaughlin in the Sleiman and Cosa laboratories have demonstrated the first examples of DNA nanotubes with deliberately controlled geometry. Remarkable triangular and square-shaped tubes spontaneously form using these new techniques.

These nanotubes offer great potential, for example, for the construction of metal nanowires of different geometries. The DNA tube can be used as a mold into which metals are grown, creating microscopically thin wires that may have a wide variety of applications. source

My comment: This sounds kind of abstract, but in fact, it's quite cool (even if somewhat creepy). If not else, they offer a way to make new stuff with those DNA tubes. What I see as a disadvantage, however, is the strength of the tubes. If they are made from organic material, they are not very likely to be tough, right? But from the other point of view, I think they would be perfect for neurons of an organic computer.


Breathing batteries could store 10 times the energy

The lithium ion batteries used in laptops and cellphones, and tipped for future use in electric cars, are approaching their technological limits. But chemists in the UK say that there's a way to break through the looming energy capacity barrier – let the batteries "breathe" oxygen from the air.

A standard lithium ion battery contains a negative electrode of graphite, a positive electrode of lithium cobalt oxide, and a lithium salt-containing electrolyte. Lithium ions shuttle between the two electrodes during charging and discharging, sending electrons around the external circuit to power a gadget in the process.

The problem with that design, says Peter Bruce at the University of St Andrews, is that the lithium cobalt oxide is bulky and heavy.

The answer, he thinks, is to borrow an idea from the zinc-air batteries used in hearing aids, which get their power reacting zinc with oxygen from air.

The new battery has a higher energy density than existing lithium ion batteries because it no longer contains dense lithium cobalt oxide. Instead, the positive electrode is made from lightweight porous carbon, and the lithium ions are packed into the electrolyte which floods into the spongy material.

When the battery is discharged, oxygen from the air also floods through a membrane into the porous carbon, where it reacts with lithium ions in the electrolyte and electrons from the external circuit to form a solid lithium oxide.

The solid lithium oxide gradually fills the pore spaces inside the carbon electrode as the battery discharges. But when the battery is recharged the lithium oxide decomposes again, releasing lithium ions again and freeing up pore space in the carbon. The oxygen is released back to the atmosphere.

The team's prototype device has a capacity-to-weight ratio of 4000 milliamp hours per gram – eight times that of a cellphone battery. Even a 10-fold improvement is possible, but tweaking conventional lithium-ion designs will likely offer only a doubling in capacity, Bruce estimates. source

My comment: That one sounds also very promising. It's interesting how you find new developments of the same issue in a certain period of time. I can't wait for the new batteries, because the old one clearly suck!


Alcohol makes autos more climate-friendly

DRIVING and alcohol don't usually mix, but giving a petrol engine an occasional slug of the hard stuff could make it as fuel-efficient as a petrol-electric hybrid.

So says the Ford Motor Company, which on 19 May revealed test results on a novel ethanol-assisted engine. Called a direct-injection ethanol engine, the unit runs primarily on petrol. When it needs to deliver maximum power - to climb a hill or overtake, for example - the engine management computer adds a little ethanol to the fuel injected into the combustion chambers.

This arrangement allows the engine to operate at a much higher compression ratio - a measure of the amount by which the fuel-air mixture is compressed before being ignited - than normal. As a result, an average car engine can be "downsized" to one that should have around 23 per cent better fuel efficiency, Ford says.

Normally, the downside of a high compression ratio is that it encourages premature ignition or "knocking", which drastically cuts down the power output. Adding ethanol to the fuel suppresses knocking.

Test results on a pickup truck fitted with the new engine were presented at the US Department of Energy's annual vehicle technology review meeting in Arlington, Virginia. They showed a 23 per cent improvement in fuel efficiency for the same performance levels. The ethanol from a 40-litre auxiliary tank would last about 30,000 kilometres, Ford says.

source

My comment: So, there is a way after all. It's amazing how much improvements one can make to an old technology, if one looks in the right direction. Sometimes, I'm sorry I'm not an engineer, because they have so much fun and so many opportunities to make clever fixes.

Solar car aims to put rivals in the shade

April 6th, 2009
(PhysOrg.com) -- Plans for a solar-powered racing car which will cruise at 60mph using the same power as a hairdryer have been unveiled by students at Cambridge University.

The car, codenamed "Bethany", will be completed this summer and is being touted as Britain's brightest hope for the World Solar Challenge - a gruelling 3,000 km race across the Australian Outback.

Its power will come from solar energy captured by a 6m² covering of high-efficiency silicon cells. Underneath this solar "skin", however, the car will essentially be an ultra-efficient electric vehicle, which designers say could provide a model for other forms of green transportation.

Using computer simulation software, the car's aerodynamics, rolling resistance, weight and electrical efficiency have all been optimised to minimise its energy requirements. It will also be fitted with an energy-efficient hub motor, a control system to provide management and an electric braking system which generates energy.

It will weigh just 170kg and its creators estimate that it will require up to 50 times less power than a normal petrol-fuelled vehicle.source

Honda Connects Your Brain to a Robot

By Yuri Kageyama / Source: Associated Press

Honda Motor Co. (HMC) has developed a way to read patterns of electric currents on a person's scalp as well as changes in cerebral blood flow when a person thinks about four simple movements - moving the right hand, moving the left hand, running and eating.

Honda succeeded in analyzing such thought patterns, and then relaying them as wireless commands for Asimo, its human-shaped robot.

In a video shown Tuesday at Tokyo headquarters, a person wearing a helmet sat still but thought about moving his right hand - a thought that was picked up by cords attached to his head inside the helmet. After several seconds, Asimo, programmed to respond to brain signals, lifted its right arm.

Honda said the technology wasn't quite ready for a live demonstration because of possible distractions in the person's thinking. Another problem is that brain patterns differ greatly among individuals, and so about two to three hours of studying them in advance are needed for the technology to work.

The company, a leader in robotics, acknowledged the technology was still at a basic research stage with no immediate practical applications in the works.

Japan boasts one of the leading robotics industries in the world, and the government is pushing to develop the industry as a road to growth.

Research on the brain is being tackled around the world, but Honda said its research was among the most advanced in figuring out a way to read brain patterns without having to hurt the person, such as embedding sensors into the skin. source

Five-Dimensional DVD Could Hold Data of 30 Blu-ray Discs

May 21st, 2009 by Lisa Zyga

(PhysOrg.com) -- While many people think that Blu-ray will replace DVDs in the near future, a new study shows that DVDs may still have a lot to offer. Researchers have designed a five-dimensional DVD that can store 1.6 terabytes of data on a standard-size DVD, which is the equivalent of about 30 Blu-ray discs. The 5D DVDs could also be compatible with current DVD disc-drive technology.

The researchers, led by microphotonics researcher James Chon from the Swinburne University of Technology in Hawthorn, Australia, have presented the new DVD high-density data storage technique in a recent issue of Nature. While scientists have been considering 3D optical data storage for a while, this is the first time data has been recorded and read in five dimensions: three dimensions of stacked layers, and two new dimensions of wavelength (color) and polarization.

The new disc is made of three thin glass films stacked on top of each other, each coated with a solution containing gold nanorods of three different sizes. To record on the disc, the researchers focused a laser on the films, heating the nanorods so that they melted into spheres (marking the switch from 0 to 1). However, the rod-to-sphere transition depends on the wavelength and polarization of light. of the three different sizes absorb different wavelengths, and must be aligned with the direction of the light's polarization to turn into spheres.

These multiple variables mean that the same volume of space can hold multiple bits in multiple ways, the researchers explain. For instance, a space that responds to three different colors and two different polarizations can hold six bits. To read the bits, the researchers scanned the surface of the disc with a laser of lower energy but the same wavelength and polarization used during writing, identifying which areas had been previously melted with that light and which hadn't.

The researchers demonstrated the write and read technique on a small area of the disc, but predict that the disc could store 140 gigabytes of information per cubic centimeter. Since the volume of a typical DVD-sized disc was about 12 cm^3, the total data capacity would be 1.6 terabytes. Adding an extra dimension, say by using another , could increase the storage capacity to 7.2 terabytes - about 140 times the capacity of a Blu-ray, which can store around 50 gigabytes.

The researchers are currently working with Samsung on the technology, and hope that it could be commercially available in the next 5 to 10 years. source

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