Sunday, December 1st, 2013

Polymers Snap in Response to Light, No Other Power needed

A recently published research paper from the University of Pittsburgh’s Swanson School of Engineering and the Air Force Research Laboratory at Wright-Patterson Air Force Base describes plastics that can “snap” when triggered by light. The light energy is converted into mechanical action with no need for traditional machine components such as switches and power sources.

“I like to compare this action to that of a Venus Fly Trap,” says M. Ravi Shankar, associate professor of engineering at Pitt, whose research focuses on innovative nanomaterials. “The underlying mechanism that allows the Venus Fly Trap to capture prey is slow. But because its internal structure is coupled to use elastic instability, a snapping action occurs, and this delivers the power to shut the trap quickly.

Shankar, collaborating with Timothy J. White of the Air Force Research Laboratory and Matthew Smith, assistant professor of engineering at Hope College (Holland, MI), focused on the elastic instability of azobenzene-functionalized polymers (both amorphous polyamides and liquid crystal polymers) prepared by the Air Force lab, which showed unprecedented actuation rates and output powers. With light from a hand-held laser pointer, the polymers generated high amounts of power that converted the light into mechanical work without any other power source.

A polymer deforms when irradiated with light (blue) and snaps, delivering a large amount of power at millisecond time scales. (Image: M. Ravi Shankar et al, University of Pittsburgh)

A polymer irradiated with light (blue)  snaps, delivering a large amount of power at millisecond time scales. (Image: M. Ravi Shankar et al, University of Pittsburgh)

“As we look to real-world applications, you could activate a switch simply by shining light on it,” Shankar said. “For example, you could develop soft machines such as stents or other biomedical devices that can be more adaptive and easily controlled. In a more complex mechanism, we could imagine a light-driven robotic or morphing structure, or micro-vehicles that would be more compact because you eliminate the need for an on-board power system. The work potential is built into the polymer itself and is triggered with light.”

Scientists have known for years about a class of photo-responsive polymers that would react to light with no other power source. Problem was, their movement was very slow. The research team shaped the polymer into a geometry resembling a hummingbird’s beak or the trap of a Venus Fly Trap plant. When irradiated with light, the polymer initially deforms slowly, but when it reaches a critical state, it snaps. Shankar told KurzweilAI they generated actuation in millisecond time-scales and power approaching kilowatts per cubic meter at radiation intensities far less than 100 milliwatts per square centimeter and potentially over long distances.

Shankar, White and Smith published their findings in the Proceedings of the National Academy of Sciences in early November. Shankar’s research was enabled through an eight-week Air Force Office of Scientific Research Summer Faculty Fellowship.

Wednesday, October 9th, 2013

High-Tech Plastic Fibers Take On Increasingly Tougher Jobs

The Economist magazine’s Technology Quarterly reports on leading-edge tech from every sector, and the latest issue once again has turned to the plastics industry for its newest and coolest. The editors did not, however, focus on obvious targets such as plastics in airplane or car bodies, micro components or another breakthrough medical device.

As the article “Material benefits” states: “…researchers around the world are now cooking up myriad new textiles capable of containing explosions, protecting astronauts, thwarting bacteria and even keeping buildings standing during earthquakes.” Textiles? Really? Yes, new fabrics and threads, small and even delicate as they may seem, are coming out of the labs to solve big — often very big — problems in a variety of sectors.

Air cargo nets of UHMWPE plastic are much stronger to stop loads breaking loose.

Newer air cargo nets of UHMWPE plastic are much stronger to keep loads in place. (Image: AmSafe Bridport)

For example, when a cargo net securing freight in an airplane breaks during takeoff, the load can shift backwards and  raise the plane’s nose enough to cause a stall. All too often the result has been a fatal crash. As a result, several major airlines recently have begun using cargo netting woven from fibers of ultra-high-molecular-weight polyethylene (UHMWPE), a plastic material much stronger than the polyester netting that has been widely used.

The strength-to-weight ratio of UHMWPE fibers is about 15 times that of steel, according to AmSafe Bridport, a British producer of cargo nets made of Dyneema UHMWPE fibers from the Netherlands-based Royal DSM Group. Though the new nets cost about four times more than the traditional nets, the they last longer and weigh about half as much, and that saves fuel, which reduces CO2 emissions. They also are easier to handle.

For this bridge in Houston, TX, Vectran LCP fiber was the lighter and stronger choice over steel cable.

For this bridge in Houston, TX, Vectran LCP fiber was a lighter, stronger choice than steel cable. (Image: Kuraray)

The Economist also describes how the Japanese firm Kuraray Group found a way to pump liquid crystal polymer (LCP) through holes 23 microns (millionths of a meter) in diameter to create fibers that are very thin yet incredibly strong. How strong? You can twist about 100,000 of them together to form a cord a bit thicker than a pencil, with which you can suspend about eight tons. Picture four SUVs hanging by that pencil-thin cord.

Branded Vectran, the material also has excellent resistance to stretching. So along with being excellent for applications such as tape and sails, the material can be used for cabling in robots to help keep their gestures precise. On a larger scale, Vectran cabling was used to retrofita pedestrian bridge over interstate highway 610 in Houston, TX — the lightweight, high-strength alternative to steel. The material also performed well in outer space.

NASA’s Pathfinder, Spirit and Opportunity missions successfully landed their Rover vehicles with the aid of airbags made with Vectran LCP fiber. But the larger size of the Mars Curiosity Rover required a new and much more complex landing system.

The LCP cords in this bridle assembly helped lower the Curiosity  Rover onto the surface of Mars. (Image Courtesy of NASA)

The LCP cords in this bridle assembly helped lower the Curiosity Rover onto the surface of Mars—gently. (Image: NASA)

The Curiosity Rover began its descent from a bit more than a mile above Mars inside an aeroshell traveling about 220 mph. It emerged tethered to a Sky Crane rocket thruster platform that slowed and positioned Curiosity near the surface. Three bridle systems and tethers containing Vectran LCP fiber lowered the Rover 25 feet to a soft landing. (The process is shown in a graphic below.)

The Economist went on to mention several other polymeric textiles used for such non-routine tasks as protecting armored vehicles and keeping buildings from collapsing in earthquakes. However, it did not mention the Dyneema-UHMWPE-fiber cables that held the capsized cruise ship Costa Concordia so it did not slide off its resting place while it was rotated upright last month in a complex 19-hour operation near the Italian island of Giglio. That merits a mention because the ship is more than three football fields long and weighs almost 115,000 tons. Those slender plastic fibers are strong indeed.

 How the One-Ton Curiosity Rover Made a Soft Landing on Planet Mars

Three bridle assemblies used LCP fibers in the last stage of gently lowering the Curiosity Rover onto the surface of Mars.

Three bridle assemblies in the Sky Crane used LCP fibers during the last stage of gently lowering the nearly-one-ton Curiosity Rover onto the surface of Mars. (Image: NASA)

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Sunday, October 6th, 2013

Turkish Student, 16, Creates Bioplastic from Banana Peels, Wins Prizes

Elif Bilgin, 16, Istanbul, Turkey

        Elif Bilgin, 16, Istanbul, Turkey

Elif Bilgin is a 16-year-old, tenth-grade student at Koc High School for gifted students in Istanbul, Turkey, and despite her youth it’s fair to say she already merits the title of scientist — award-winning scientist in fact. Bilgin’s ultimately successful two-year search for a way to make bioplastics material from banana peels earned her a place as one of fifteen finalists in the recently concluded 2013 version of the global Google Science Fair. Further, her project won the Voter’s Choice Award and the Science in Action Award sponsored by Scientific American, which gives her a prize of $50,000 and a one-year mentorship program.

Bilgin originally chose to focus on bioplastic because of its potential for causing a biological shift away from producing plastics based on petroleum, a shift that is already well underway. If, she wrote, “…plastic (a material with such great range of use in our daily lives) can be manufactured by the use of banana peels (a material which is thrown away every day), then this plastic would become a rival to the petroleum-based plastic we use nowadays”.

Eat the fruit, turn the peels into bioplastics.

Eat the fruit, turn the peels into bioplastics.

“The reason why I was able to [make bioplastic from banana peels] was because fruits rich with starch are preferred in the making of bio-plastic and the banana peel is rich with starch.” A more detailed description of Bilgin’s process and her experiments can be found here.

The young lady was working on her project long before she knew about the Google Science Fair. When the project was nearly complete she began looking for a competition to enter. Not surprisingly, she used the Google search engine to look for “science project competitions.” Surely you can guess what came up as the first result. Bilgin calls it a happy coincidence.

The Google Science Fair is an online competition open to student aged 13 to 18 from around the globe. We in America often hear of the decline in the national educational system. It should be of some comfort to know that of this year’s 15 finalists, eight are from the USA, and the winner of the 17-18 age group and the Google Science Fair Grand Prize, is Eric Chen, a 17-year-old junior at Canyon Crest Academy in San Diego, CA.

Chen’s project is Computer-Aided Discovery of Novel Influenza Endonuclease Inhibitors to Combat Flu Pandemic. One of his idols is Dr. Jonas Salk, the discoverer of the world-changing polio vaccine, and Chen has already served as a teaching assistant for college-level classes at his school.

Given the advanced nature of the projects in this competition, using the term school kids to describe the young scientists feels totally inappropriate, but whatever we call them, it is reassuring to know that these youngsters are moving into the scientific mainstream. Kudos to Google and Scientific American for encouraging and recognizing them.

The awards were presented on September 23, 2013 at Google’s Mountain View, CA campus, with all 15 of the finalists brought in for the event. Should you know of a budding scientist that should be involved in the Google Science Fair, the competition will re-open for entries in January 2014. In the meantime, updates are available from Google here.

 Elif Bilgin, 16, of Istanbul, Turkey, Student Scientist

Wednesday, August 14th, 2013

Google Testing Global Internet Access Via Polyethylene Balloons

In June 2013 Google staged the first test of a pilot project aimed at bringing high-speed wireless Internet access to rural, remote or underserved parts of the world. Project Loon, as Google named it, exemplifies the outside-the-box thinking that seems to go with the Google brand. Think of plastic Balloons carrying communications hardware and software, powered by solar panels hanging below them, circling the earth at an altitude of about 66,000 ft. (20+ km) and providing Internet access from the planet’s surface, no matter how remote the location.

Raven Aerostar Super Pressure Balloons 60 feet tall and 60 feet in diameter are being tested for Google’s Project Loon.

Raven Aerostar Super Pressure Balloons 60 feet tall are being tested for Google’s Project Loon.

Outside the box, yes, but Google aims to have everyone on earth able to use the Internet, regardless of their location.

Google can supply the communications gear, both hardware and software, but not the balloons, especially balloons up to the task. But the Raven Aerostar division of Raven Industries (both in Sioux Falls, SD), which has been on the cutting edge of lighter than air technology for nearly 60 years can. We can assume Google had no problem searching for them.

Remember Felix Baumgartner’s jump to earth from the edge of space last year? Raven Aerostar made the balloon that carried his capsule to an altitude of 128,000 ft. (39 km).

The balloons carrying Google Internet access technology will circle earth at 66,000 feet (20 km).

The balloons carrying Google Internet access technology will circle earth at 66,000 feet (20 km).

The trials that were done by Google and Raven from near Christchurch, New Zealand went very well. About 25 balloons were flown in four to five days, and both the balloons and the communications technology were reported to have worked very well.

The Super Pressure Balloons Raven Aerostar made for the trial run of Project Loon are pumpkin-shaped, 60 ft. high and 60 ft. in diameter. Since they would carry 30,000 pounds of pressure, cruise at 67,000 feet altitude and be in temperatures between -60ºC and -80ºC, they must be made of an exceptional material. The material is only three mils thick—0.003 inch, yet it is strong enough to allow pressure changes that occur through the diurnal cycle to enable a more constant altitude for a longer time. You can see through it, yet it aims to survive at 67,000 feet for about 100 days before being controlled back to earth and replaced by another balloon.balloon-+-people-250w

This high performance material supplied by Raven Engineered Films, also located in Raven’s 330,000-square-foot facility in Sioux Falls, is none other than polyethylene (PE), the same polymer used to make bread wrappers and the lightweight plastic bags used to carry groceries home from the store. However, though it may be the same basic polymer, the polyethylene Raven uses to make its Super Pressure Balloons is formulated and the film is manufactured specifically for the balloon’s extreme operating environment. It is an outstanding example of the versatility of what is generally referred to as a commodity plastic.

The pilot test of Project Loon held in June marks the start of a cooperative development process between Google and Raven, and it’s a promising start for a creative approach to bringing broadband Internet access to remote and developing parts of the world. An impressive description of Project Loon is available on Google’s website.

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Sunday, July 14th, 2013

USDA Reopens Web Portal for Certified Biobased Product Label Applications

As a strong supporter of U.S. Dept. of Agriculture’s BioPreferred Program, the SPI Bioplastics Council, which is a committee of SPI: The Plastics Industry Trade Association, is calling attention to the reopening of the web portal that allows online application for the USDA Certified Biobased Product Label.

The news of the web portal’s reopening was contained in an announcement made on July 11, 2013 by Agriculture Secretary Tom Vilsack of eight new biobased product categories (listed below) for preferred federal procurement.

SPI’s Bioplastics Council is calling association members’ attention to the reopening of the web portal.

In conjunction with announcing the web portal’s reopening, the BioPreferred Program noted that so far about 900 individual products have received the USDA Certified Biobased Product Label. The Program is expected to finalize a rule later this year that will extend to designating intermediate ingredients so that products made from them could be part of the federal preferred procurement process. The rule would also allow for designation of complex assemblies that contain one or more components from biobased ingredients.

The BioPreferred Program was authorized in the 2002 and 2008 Farm Bills. A new version of the Farm Bill that was passed on July 11, 2013 by the House is contentious and is expected to face opposition in the Senate and a possible Presidential veto, based on the administration’s initial understanding of the House bill’s content. Debate on the Farm Bill is expected to continue into the fall, according to the Washington Post.

In yesterday’s announcement, Secretary Vilsack noted that a long-term Food, Farm and Jobs Bill is critical to continued USDA investment in the BioPreferred Program. He said, “A Food, Farm and Jobs Bill would help grow opportunity for the creation of biobased products across rural America – expanding manufacturing, and creating jobs.”

As a practical matter, applying for a USDA Certified Biobased Product Label requires first applying for and receiving a Level 1 USDA eAuthentication account, which provides a user ID and password needed to complete the actual electronic application for the Label. Click here for the application starting page on the USDA BioPreferred Program website.

As promised above, the eight new biobased product categories that USDA has designated for preferred federal procurement are: aircraft and boat cleaners; automotive care products, engine crankcase oil; gasoline fuel additives; metal cleaners and corrosion removers; microbial cleaning products; paint removers; and water turbine bearing oils. A full list was published in the June 11, 2013 Federal Register.