Stories tagged nanotechnology
Nanotechnology is the ability to create and manipulate atoms and molecules on the smallest of scales. Will this emerging science revolutionize the world we live in?
Solar cells that work at night
Solar cells become ineffective when the sun goes down. At night, the earth radiates heat back toward the sky. Scientists at the U.S. Department of Energy's Idaho National Laboratory are working on a device to turn infrared radiation into electricity.
Nanoantennas convert infrared rays into electricity
Billions of nanoantennas printed onto thin, inexpensive sheets will transform heat energy into electricity. The physics behind this conversion is the same as that of a radio antenna. The only difference between radiowaves and infrared light is wavelength. Antennas 1/25 the size of a human hair resonate when bombarded with heat radiation. If the resulting alternating current can be passed through a rectifier (one way valve) the current can charge up batteries. The infrared rays create alternating currents in the nanoantennas that oscillate trillions of times per second.
"Today's rectifiers can't handle such high frequencies. "We need to design nanorectifiers that go with our nanoantennas," says Kotter, noting that a nanoscale rectifier would need to be about 1,000 times smaller than current commercial devices and will require new manufacturing methods. Another possibility is to develop electrical circuitry that might slow down the current to usable frequencies." Eureka Alert
If these technical hurdles can be overcome, nanoantennas have the potential to be a cheaper, more efficient alternative to solar cells. Computer models of nanoantennas predict up to 92% efficiency (compared to solar cells around 20%).
Learn more in this video, "Harvesting the sun's energy with antennas"
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Stained-glass windows: Uplifting to look at, and good for your physical health, too.
Courtesy Mark RyanWhile Gene continues obsessing over the ways of the flesh (see below, and here), I shall take the high road and offer this post that involves both our corporeal and spiritual realms.
A recent study out of Australia's Queensland University of Technology shows that tiny particles of gold embedded in the paint of stained glass windows not only add to the beauty of church windows (which no doubt enhance the experience of being inside the church), but also have some health benefits.
It seems medieval glaziers, who could be considered the first nanotechnologists, used different sized gold particles to create a variety of colors. The windows produced over the centuries for churches across Europe are certainly uplifting to look at, but until now nobody realized the additional health benefits they carry for our physical beings.
What happens is when sunlight illuminates the stained glass, the gold nanoparticles resonate as they heat up. This resonance increases significantly the magnetic field across the element’s surface that in turn interacts with and destroys nasty pollutants like volatile organic compounds (VOCs) that are present in the air.
"These VOCs create that 'new' smell as they are slowly released from walls and furniture, but they, along with methanol and carbon monoxide, are not good for your health, even in small amounts," said associate professor Zhu Huai Yong, a member of the team that did the study.
The chemical reaction purifies the air with only small amounts of carbon dioxide as a byproduct. Yong is excited about the prospect of using gold nanoparticles in future research.
"Once this technology can be applied to produce specialty chemicals at ambient temperature, it heralds significant changes in the economy and environmental impact of the chemical production," he said.
The NYTimes has a great piece about the potential ramifications of science's latest breakthrough discoveries: nanotechnology, robotics, geo-engineering. I used to think that just about anything we could develop, would be developed. Articles like this have helped educate me that we do have a choice as a society about where and when we allow science to go. It's an interesting read.
The shrinking radio: Courtesy Zettl Research Group, Lawrence Berkeley National Laboratory and University of California at Berkeley.
Courtesy Zettl Research Group
Tiniest radio yet
A fully integrated radio receiver, orders-of-magnitude smaller than any previous radio, was made from a single carbon nanotube (CNT).
When a radio wave of a specific frequency impinges on the nanotube it begins to vibrate vigorously. An electric field applied to the nanotube forces electrons to be emitted from its tip.
This nanotube radio is over 10,000,000,000,000,000,000 times smaller than the Philco vacuum tube radio from the 1930s.
The single nanotube serves, at once, as all major components of a radio: antenna, tuner, amplifier, and demodulator. (Berkely physics research)
See and hear a nano radio
Videos from an electron microscope view of the nanotube radio playing two different songs are linked below.
- Good Vibrations (Quicktime, 8.06 MB)
- Star Wars (Quicktime, 8.68 MB)
Farm animals often carry germs that can get into our food supply. And pumping the animals full of antibiotics can cause other problems, such as breeding super bugs that are immune to the drugs. But researchers in South Carolina are taking a new approach. They are adding nanoparticles to chicken feed. The particles imitate chicken cells and attract the germs. The germs get stuck to the particles, and then get expelled harmlessly the next time the chicken poops.
Nano structure self assembly
Courtesy Scott Warren and Uli Wiesner, Cornell University
Materials scientists perfect nano assembly of catalytic meshes
Catalysts, because of its shape, can speed up chemical reactions. Platinum is a useful catalyst in fuel cells but because it costs over $2000 an ounce, it needs to be used efficiently. One way to maximize the effectiveness of platinum is to maximize its surface area.
Cornell researchers have developed a method to self-assemble metals into complex configurations with structural details about 100 times smaller than a bacterial cell by guiding metal particles into the desired form using soft polymers. NSF News
How to self-assemble porous nano mesh
To keep nano spheres of platinum from clumping or "globbing" they are coated with an organic material known as a ligand. The innovative use of the ligands allows for the metal nanoparticles to be dissolved in a solution containing long co-polymer chains, or blocks, of molecules linked together to form a predictable pattern. After the spheres have filled in the spaces created by the co-polymer chains, heat is applied until the polymer turns to a carbon scaffold. The scaffold holds the platinum spheres in place until cooled. The carbon is then dissolved away leaving an intricate hexagonal mesh of platinum (see image above).
New surface textures will benefit plasmonics science
These metalic surfaces will also be of interest to scientists working in an area called plasmonics. Plasmonics is the study of interactions among metal surfaces, light, and density waves of electrons, known as plasmons. Improved optics applications, like lasers, displays, and lenses and better transmission of information within microchips will be some benefits.
Are nanomaterials safe?
Nanomaterials & health
Courtesy GiselaGiardino²³Nanomaterials show promise for curing diseases. But, how can we assess the risk of these nanomaterials causing problems within the human organism. Studies in animals are expensive and time consuming. Also, different cell types can respond differently to the same nanomaterial.
A fast screening method could help separate the good from the bad
Stanley Shaw and researchers from the Broad Institute of Harvard and MIT recently tested 50 different nanoparticles--mainly particles used for medical imaging, including mostly iron-based particles, as well as several types of quantum dots. The particles also had various chemical coatings.
The researchers tested each of the nanoparticles in four different types of cells--immune cells from mice, two types of human blood-vessel cells, and human liver cells--and at four different dosages. To create the different combinations, a robotic system similar to that used for drug screening placed the nanoparticles inside tiny wells on a plate containing hundreds of separate wells. Each well contained one cell type. The screening system then detected changes in the cells' metabolism in response to the nanomaterial. Computer software analyzed the data, looking for relationships between the different particles. Technology Review
The new screening tool, described in the Proceedings of the National Academy of Sciences, could help narrow the list of nanomaterials that need to undergo animal testing.
"Paper towel" can clean up oil spills
Researchers at MIT have combined a nanowire mesh with a water-repellant coating that can absorb up to 20 times its weight in oil. The oil absorbed can be recovered and the "paper towel" can be reused many times.
"Made of potassium manganese oxide, the nanowires are stable at high temperatures. As a result, oil within a loaded membrane can be removed by heating above the boiling point of oil. The oil evaporates, and can be condensed back into a liquid. The membrane--and oil--can be used again." MIT News
Last weekend, NIST (the guys who keep track of what time it is) hosted a RoboCup nanosoccer exhibition match, where the playing field was smaller than a grain of rice. Read more about the nanobot soccer match at BotJunkie.
Carbon nanotubes
Courtesy St StevA new study published in the scientific journal Nature Nanotechnology shows that longer fibers of carbon nanotubes seem to mimic asbestos when injected into the abdomens of mice. This raises new safety concerns for the up-and-coming technology.
When the mice were injected with asbestos and with various sizes of carbon nanotube samples, the researchers discovered that the longer nanotubes acted in the same way as the asbestos, causing inflammation and lesions. Exposure to asbestos is considered the main cause of a cancer known as mesothelioma.
Just like nanotechnology today, asbestos was once considered a wonder material until its cancer-causing effects on the protective covering (mesothelium) of the body’s organs were realized.
Read more here.
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