New Materials Can Self-Replicate

One of the hallmarks of living things is self-replication, the ability to make new copies of biological structures. Scientists have harnessed this ability in several ways, using DNA and viruses to organize materials for things like solar panels. But inducing artificial self-replication, which would enable new types of self-fabricating materials, has proven more difficult. Now researchers at New York University say they’ve taken a step in that direction, building a complex artificial system that can self-replicate.

The researchers started with artificial DNA tile motifs, which are tiny arrangements of DNA. Just like the base pairs of DNA, the tiles each serve as a letter, each of which pairs with another specific letter. DNA’s A-T and G-C pairs form the molecule’s double helix. In this case, the tiles were made of artificial bent triple-helix molecules, each containing three DNA double helices. The researchers wanted to use this motif to seed the creation of a new structure, which would be based on the rules established by the seed.

To do this, they created a sequence of seven tiles, or seven “words,” to serve as the seed, and placed the molecules in a solution. There it matched up with complementary tiles, and assembled into a daughter array. Then the molecules were heated up, separating the daughter tiles from the seed. The process started again, with the daughter array matching with new complementary tiles and assembling a granddaughter array — and so on.

The second-generation tiles reproduced the same sequence as the seed word, without any enzymes or other biological triggers, according to the NYU team.

It’s worth noting that the seed word was pretty much arbitrary — so the work shows that self-replicating materials can be created from any seed composition, said Paul Chaikin, an NYU physics professor and one of the study's co-authors, said in a university news release.

This is a long way from being used in materials fabrication, of course, but the work shows it is possible.

“Our findings raise the tantalizing prospect that we may one day be able to realize self-replicating materials with various patterns or useful functions,” the researchers write.

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Posted in: biological,biology,enzymes,materials,molecules,New Materials Can Self-Replicate,solar panel

Snackable Sponge Can Suck Up CO2

Sponges already clean up kitchen spills and soap scum, now they may start cleaning up the atmosphere.

A newly-developed synthetic sponge made of salt, sugar, and alcohol soaks up carbon dioxide. It's non-toxic, reusable, and carbon neutral. In a pinch, you can even make a meal of it.

Northwestern University chemists developed this special sponge, known as a metal-organic framework (MOF). Other MOFs soak up carbon dioxide too, but are usually made from crude oil and contain more toxic heavy metals than Beavis and Butthead's record collection.

 The new sponges don't pollute the environment while cleaning it up. In fact, their manufacture could reduce the amount of greenhouse gas in the air, since they contain sugar made by plants which themselves pull carbon dioxide out of the air.

“We are able to take molecules that are themselves sourced from atmospheric carbon, through photosynthesis, and use them to capture even more carbon dioxide,” said Ross Forgan, a co-author of the sponge study published in Journal of the American Chemical Society, in a press release.

“By preparing our MOFs from naturally derived ingredients, we are not only making materials that are entirely nontoxic, but we are also cutting down on the carbon dioxide emissions associated with their manufacture,” said Forgan.

The main ingredient is gamma-cyclodextrin, a type of sugar derived from corn, held together in a crystalline structure by metals, such as potassium benzoate and rubidium hydroxide, derived from salts.

Despite the intimidating names of its ingredients, the MOF carbon sponge is actually edible.  But don't sit down to a sponge lunch just yet, the carbon-hungry sponges can be cleaned and reused.

“It turns out that a fairly unexpected event occurs when you put that many sugars next to each other in an alkaline environment -- they start reacting with carbon dioxide in a process akin to carbon fixation, which is how sugars are made in the first place,” said Jeremiah J. Gassensmith, lead author of the paper, in a press release.

“The reaction leads to the carbon dioxide being tightly bound inside the crystals, but we can still recover it at a later date very simply,” Gassensmith said.

The MOF sponges suck in the carbon dioxide and converts it to carbonate. But when exposed to an atmosphere with low concentrations of carbon dioxide, the gas is released.

Unlike other methods of carbon capture, little extra energy is needed to release the carbon dioxide.

"In our material, the CO2 is converted into a solid, most likely by reacting with the sugar, but if you blow a stream of nitrogen over the material, the CO2 spontaneously pops off and will go wherever you blow it, and the material is reused and thus recyclable.

"It is thus a very, very green way of trapping CO2," Gassensmith said.

The sponges could be used to scrub emissions or the air itself. The excess carbon can then be used in other industrial processes or stored somewhere.

The sponge even lets people know when it's ready for a cleaning.

The researchers included methyl red, a common chemical pH indicator, in the sponges to let them know when the sponge has soaked up all the carbon it can. A pH shift within the sponge causes the color to change from yellow to red when it is full of carbon.

Since the MOF carbon sponges are cheap and easy to manufacture, not to mention eco-friendly, Northwestern plans to pursue commercialization opportunities.

“I think this is a remarkable demonstration of how simple chemistry can be successfully applied to relevant problems like carbon capture and sensor technology,” said Ronald A. Smaldone, a co-author of the paper.

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Posted in: atmosphere,carbon dioxide,environment,materials,nitrogen,nontoxic,recyclable,Snackable Sponge Can Suck Up CO2

The "Flying Carpet"

The sheet is lifted by the air packets, and propelled forwards

A miniature magic carpet made of plastic has taken flight in a laboratory at Princeton University.

The 10cm (4in) sheet of smart transparency is driven by "ripple power"; waves of electrical current driving thin pockets of air from front to rear underneath. 

The prototype, described in Applied Physics Letters, moves at speeds of about a centimeter per second.

Improvements to the design could raise that to as much as a meter per second.

The device's creator, graduate student Noah Jafferis, says he was inspired by a mathematical paper he read shortly after starting his PhD studies at Princeton.

He abandoned what would have been a fashionable project printing electronic circuits with nano-inks for one that seemed to have more in common with 1001 Nights than 21st-Century engineering.

Prof James Sturm, who leads Mr Jafferis' research group, conceded that at times the project seemed foolhardy.

"What was difficult was controlling the precise behaviour of the sheet as it deformed at high frequencies," he told the BBC. 

"Without the ability to predict the exact way it would flex, we couldn't feed in the right electrical currents to get the propulsion to work properly."

What followed was a two year digression attaching sensors to every part of the material so as to fine-tune its performance through a series of complex feedbacks.

But once that was mastered, the waveform of the undulating matched that prescribed by the theory, and the wafting motions gave life to the tiny carpet.

In the paper describing the design, Mr Jafferis and his co-authors are careful to keep the word "flying" in inverted commas, because the resulting machine has more in common with a hovercraft than an aeroplane.

"It has to keep close to the ground,  because the air is then trapped between the sheet and the ground. As the waves move along the sheet it basically pumps the air out the back." That is the source of the thrust.

Ray hope

  

Harvard University's Lakshminarayanan Mahadevan, who wrote the 2007 paper in Physical Review Letters that inspired the whole project, expressed a mixture of surprise and delight at the Princeton team's success.

                                   The propulsion is not completely unlike that of skates and rays

"Noah has gone beyond our simple theory and actually built a device that works," he told the BBC "And what's more, it behaves, at least qualitatively, as we had predicted."

Mr Jafferis points out that the prototype is limited because tiny conducting threads anchor it to heavy batteries, so it's free to move only a few centimetres. But he is already working on a solar-powered upgrade that could freely fly over large distances.

The advantage of this kind of propulsion, he argues, is that unlike jets, propellers and hovercraft, there are no moving components like cogs and gears that rub against each other.

"The ideal use would be some kind of dusty, grimy environment where moving parts would get gummed up and stop," he explained.

That said, he laughingly admits that with the existing materials, a flying carpet powerful enough to carry a person would need a wingspan of 50 metres - not the best vehicle to take on the streets just yet.

On the other hand, preliminary calculations suggest that there is enough atmosphere on the planet Mars to send floating rovers scudding over its dusty surface.

Meanwhile, Prof Mahadevan looks forward to sophisticated improvements in the near future, suggesting the approach could progress to "mimicking the beautiful two-dimensional undulations of the skate or manta ray". 

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Posted in: centimeter,flying carpet,materials,plastic,propulsion,technology

Food-based Plastics A Good Idea?

Once upon a time, food was used for one thing: eating. Today, it has a much more complicated role; scientists, manufacturers and policy makers are exploring whether food could one day eliminate our dependence on oil. Food-based fuels like ethanol and biodiesel are increasingly replacing gasoline and diesel in our fuel tanks. Now, some think food can do the same thing to the plastics industry, helping to replace more than 900,000 barrels of oil and natural gas used to manufacture plastic in the United States daily [source: U.S. EIA].

Food-based plastics, made out of everything from corn to sugarcane, have rapidly grown in popularity over the past several years. Packaging materials, gift cards, cell phone casings -- all can be made from these eco-friendly materials. As the quality of food-based plastics improves, they will have broader and broader applications.

Proponents cite two main advantages of food-based plastics over their petroleum-based counterparts. First, they're made from a renewable resource. As long as farmers grow the crops these plastics are made out of, production can continue indefinitely. Second, food-based plastics are widely considered to be easier on the environment. For instance, they require much less energy to produce than traditional plastics and release fewer greenhouse gases in the process. Better yet, they break down into harmless organic compounds -- in the right conditions.

Now for the drawbacks. One of the most glaring is their relatively low melting point. While popular plastics like polyethylene terephthalate (PET) may have melting points well beyond 400 degrees Fahrenheit (204 degrees Celsius), some plant-based plastics turn into puddles just from being left in a car on a sunny day [source: Machinist Materials]. For instance, polylactic acid (PLA), a corn-based plastic used by retail giant Wal-Mart among other companies, can have a melting point of just 114 degrees Fahrenheit (46 degrees Celsius) [source: Royte]. As a result, food-based plastics are simply unsuitable for a wide range of applications.

What's more, food-based plastics may not be as environmentally friendly as they appear. While they are biodegradable, most only break down under very specific conditions found in industrial composting plants. That means you can't simply throw them on the compost pile in your backyard and expect them to turn into soil, and if they do end up in a landfill, they break down just as slowly as conventional plastics.

While food-based plastics can be recycled, they can't simply be mixed in with other recyclable plastics. In fact, the recycling industry considers food-based plastics a "contaminant" that takes time and money to process.

A final argument against food-based plastics is that generating them requires land and resources that could be going to producing actual food. Already, the U.S. Department of Agriculture (USDA) estimates that, by 2014, nearly a quarter of all grain production will go toward making ethanol and other biofuels; if food-based plastics take off, that number could climb even higher [source: Baker and Zahniser]. Environmentalists also worry about the harmful effects of the pesticides and genetically modified crop strains used to create some of these plastics.

But don't give up on food-based plastics yet. While they still represent less than 1 percent of the plastics market, some very large companies have committed to both improving and using the plastics moving forward [source: Environmental Leader]. 

For instance, electronics manufacturers Panasonic and NEC have both announced the development of food-based plastics with significantly improved durability, heat resistance and ease of production compared to products currently on the market. Metabolix, another bioplastics manufacturer, has developed a plastic called Mirel that biodegrades in normal compost piles. 

Production costs for food-based plastics are rapidly dropping as well, which, coupled with their widening range of applications, will make them a much stronger alternative to conventional plastics moving forward. Perhaps the strongest argument for food-based plastics, however, is that after we've finally exhausted our supply of oil, they'll still be waiting for us.

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Posted in: contaminant,environment,Food-based Plastics A Good Idea?,gasoline,landfill,materials,plastics

What Is Asteroid Mining?

If you enjoy science fiction, then you know that the thought of colonizing the moon makes for some incredibly imaginative stories. But there is a good possibility that lunar cities will become a reality during the 21st century! Colonizing Mars is another option as well. 

Right now, one of the biggest problems with the idea of a moon colony is the question of building supplies. There is no Home Depot on the moon, so the building supplies have to come from somewhere. The only place to get the supplies right now is the Earth, with the space shuttle acting as a truck. Using the space shuttle in this way is something like using FedEx to get all of the materials for building a house to a construction site -- It's incredibly expensive and not very efficient!  

Asteroids may be a much better place to get the supplies. Early evidence suggests that there are trillions of dollars' worth of minerals and metals buried in asteroids that come close to the Earth. Asteroids are so close that many scientists think an asteroid mining mission is easily feasible. Several international organizations are developing plans for going up to get these natural space resources.

  

Strip-mining equipment extracts iron and other raw materials from an asteroid. In the foreground, a mining cart transports the materials to a processing plant.

 Scientists think asteroids are leftover material from the early formation of the solar system or debris from the destruction of a planet. There are tens of thousands of asteroids circling the sun. Most are grouped inside the asteroid belt, between the orbits of Mars and Jupiter. Some asteroids that stray from this orbit, though, flying close to Earth on occasion -- you've probably heard about the possibility of these asteroids smashing into Earth in the future, as in the movie "Armageddon." 

Most asteroids fit into three basic categories:

• C-type - More than 75 percent of known asteroids fit into thins category. The composition of C-type asteroids is similar to that of the sun without the hydrogen, helium and other volatiles.
• S-type - About 17 percent of asteroids are this type. These contain deposits of nickel, iron and magnesium.
• M-type - A small number of asteroids are this type, and they contain nickel and iron. 

Even without a manned mission to do a full-scale study of an asteroid, scientists know a lot about what asteroids contain. Astronomers use telescopic spectroscopy, which analyzes light reflected from the asteroid's surface, to find out what might be there. In addition to iron, nickel and magnesium, scientists think water, oxygen, gold and platinum also exist on some asteroids. 

Water interests space explorers most because it could help keep a space colony alive. Without water, there is really no way to move forward with human exploration of space. Water could also be broken down into hydrogen and oxygen to form rocket engine propellant. The metal ore on the asteroids could be mined and used for building spacecraft and other structures for a space colony. 

Corporations that might not be interested in exploring space for the adventure and science could be interested in the treasures that a space mining operation could send back to Earth. One NASA report estimates that the mineral wealth of the asteroids in the asteroid belt might exceed $100 billion for each of the six billion people on Earth. John S. Lewis, author of the space mining book Mining the Sky, has said that an asteroid with a diameter of one kilometer would have a mass of about two billion tons. There are perhaps one million asteroids of this size in the solar system. One of these asteroids, according to Lewis, would contain 30 million tons of nickel, 1.5 million tons of metal cobalt and 7,500 tons of platinum. The platinum alone would have a value of more than $150 billion! 

Asteroids have amazing potential for industry. But what will it take to land on an asteroid, find these valuable materials, extract them and process them? In the next section, you will find out how asteroid mining operations might supply the Earth and its colonies on other planets with a plenitude of materials. 

  

Asteroid Extraction and Processing

The drive to set up a mining operation on an asteroid is a matter of simple economics. While building an asteroid mine will cost billions of dollars, it will be far cheaper than carrying supplies from Earth to the moon or Mars. 

Spacecraft would have to carry food and supplies for the mining crew and the equipment for the mine. Newly developed spacecraft should make landing on an asteroid possible. After all, we have already landed on the moon, and some asteroids pass by closer than the moon. A spacecraft going to an asteroid would need less rocket power and fuel than one going to the moon. 

One problem will be how to keep the asteroid from rotating while it's being mined. Some experts suggest attaching rockets to the asteroid to take the spin out of it. But once miners land on the asteroid, just how do they plan to dig on it, process the materials extracted and transport it to a space colony or to Earth? 

No one knows for sure what the first asteroid mine will look like, but here are some good assumptions:

• The machinery will likely be solar powered, to reduce the need for fuel that would have to be hauled to the asteroid by spacecraft.
• The equipment will also have to be lightweight to transport it to the asteroid.
• Some experts, including Lewis, have favored using robotic equipment to limit the personnel needed to carry out the mining project. This would reduce the amount of supplies, like food, required for a manned mission.
• Miners on asteroids would use techniques similar to those used on Earth. The most likely method would be to scrape desired material off the asteroid, and tunnel into veins of specific substances. Scraping, or strip mining, will pull out valuable ore that will float off the asteroid.
• Because much of the ore will fly off, a large canopy might be used to collect it.
• Asteroids have nearly no gravity, so the mining equipment, and the astronaut-miners who operate it, will have to use grapples to anchor themselves to the ground. However, the lack of gravity is an advantage in moving mined material around without having to use much power.
• Once a load of material is ready to be sent to either Earth or a space colony, rocket fuel for a ferrying spacecraft could be produced by breaking down water from the asteroid into hydrogen and oxygen.
• After an asteroid's minerals and resources have been exhausted by the mining project, the equipment can then be transported to the next asteroid. 

Because of the lack of gravity and atmosphere, ferrying the newly mined materials to the moon will be easy. Once there, they can be refined and formed into structures! 

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Posted in: asteroids,jupiter,mars,materials,moon,solar power,space,spacecraft,What Is Asteroid Mining

How Solar Technology Has Advanced

Researchers and scientists are not sleeping until they get an advanced for of Photovoltaic module technology. Their desire is to provide more energy independence and somehow they have a number of breakthroughs that we can count. For your information, PV module is the panel that converts the energy from sun to electricity for use. Let us consider 5 advancements that they have come up with.

Third- Generation Solar Cells

This one uses silicon and thin cadmium telluride films and copper indium gallium seledine to convert sun rays into electricity. It is a traditional solar cell.

Sensor Solar Panels

These are flat sheets of interconnected solar cells that have the capacity to automatically track sun’s power up to about 500 to 1000 times. It generates 25 kilowatts of electricity while at its peak.

Stirling Energy System

This is a more refined design that suits deserts better. It uses thermal energy to heat a gas which expands and pushes the piston. Then, during the cooling phase of the gas, contraction occurs and the engine is cycled. This engine is about 30 percent efficient.

 High-Performance Photovoltaic

Once the national renewable energy laboratory is done with this, it would bring about high efficiency technologies for the commercial sector. It aims at doubling the conversion rate of the PV technologies.

Building-Integrated Photovoltaic

This one is also under research phase at the national renewable energy laboratory. It would help with the integration of PV panels into buildings as they are constructed. It will eventually eliminate building materials like roofs, windows, overhangs and walls and it would make the buildings more beautiful.

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Posted in: electricity,energy,environment,How Solar Technology Has Advanced,kilowatts,materials

Micro-explosion reveals new super-dense aluminium

Although materials scientists have theorized for years that a form of super-dense aluminum exists under the extreme pressures found inside a planet’s core, no one had ever actually seen it. Until now.

A team including researcher Arturas Vailionis of SLAC and Stanford blasted tiny bits of sapphire with a new table-top laser device that penetrates crystals and sets off micro-explosions inside them, creating powerful shock waves that compress the surrounding material. Under these extreme conditions – terapascals of pressure and temperatures of 100,000 Kelvin – warm dense matter forms, the state of matter between a solid and a plasma.

Because sapphire is a form of aluminum oxide, or alumina, researchers expected to find evidence of various phases of high-pressure alumina inside the gem. Instead, they observed minuscule amounts of a surprisingly stable, highly-compressed form of elemental aluminum called body-centered cubic aluminum.

Their results appear in yesterday’s edition of Nature Communications. The team included scientists from Australia, Japan, and the Carnegie Institution of Washington.

Vailionis, a researcher with the Geballe Laboratory for Advanced Materials and Stanford Institute for Materials & Energy Sciences, examined the interior of the sapphire and found the novel form of aluminum with a beam of X-ray light from the Advanced Photon Source at Argonne National Laboratory. The laser experiment itself was performed at Shizuoka University in Japan.

“High pressure experiments generally are done either with big equipment or with a diamond anvil cell where two diamonds are squeezing a tiny bit of material, but even diamond gives up at a certain point with those pressures,” Vailionis said. “But this very short pulse of laser light actually ionizes all the material within a very small volume over a short time and creates a plasma which is under enormous pressure and temperature” without fracturing the outer shell of the sapphire.

Of particular note, the paper says, is that the team “demonstrated that high energy density produced in a simple tabletop experiment makes it possible to form an exotic high-density material phase which could not be produced by other means.”

While scientists long have predicted that new classes of materials with unusual combinations of physical properties should exist under extreme pressure and temperature conditions, only hcp-Al, the hexagonal close-packed aluminum phase, had been observed previously.  The form made in this experiment is bcc-Al, or body-centered cubic aluminum.

Vailionis said he doesn’t expect the research to result in production of new materials in large quantities any time soon, but he believes the equipment used in the experiment offers a new strategy for synthesizing nanoscale amounts of new materials in the laboratory, and opens new possibilities for tabletop research into warm dense matter – the state of matter between a solid and a plasma. Such work could bring scientists a step closer to understanding Earth’s early history.

“Now we’re thinking about different materials we could use to recreate some of the environments that existed deep in the Earth’s core when the planet was forming,” he said.

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Posted in: alumina,aluminium,biological laser,earth,materials,scientists,temperature