#Laser device sniffs out tiny traces of explosives University of California Berkeley rightoriginal Studyposted by Sarah Yang-Berkeley on July 24 2014mechanical engineers have found a way to dramatically increase the sensitivity of a light-based plasmon sensor.
The nanoscale plasmon sensor used in the lab experiments is much smaller than other explosive detectors on the market.
Because of this the researchers are hopeful that their plasmon laser sensor could detect pentaerythritol tetranitrate or PETN an explosive compound considered a favorite of terrorists.
The sensor represents the latest milestone in surface plasmon sensor technology which is used now in the medical field to detect biomarkers in the early stages of disease.
By coupling electromagnetic waves with surface plasmons the oscillating electrons found at the surface of metals researchers were able to squeeze light into nanosized spaces
but sustaining the confined energy was challenging because light tends to dissipate at a metal s surface.
The new device builds upon earlier work in plasmon lasers by Zhang s lab that compensated for this light leakage by using reflectors to bounce the surface plasmons back and forth inside the sensorâ##similar to the way sound waves
The amplified sensor creates a much stronger signal than the passive plasmon sensors currently available
which work by detecting shifts in the wavelength of light Zhang says. he difference in intensity is similar to going from a light bulb for a table lamp to a laser pointer.
#Spinach leaves vibrate to kick off photosynthesis Vibrations deep within spinach leaves enhance the efficiency of photosynthesishe energy conversion process that powers life on our planet.
The discovery could potentially help engineers make more efficient solar cells and energy storage systems. It also injects new evidence into an ongoing uantum biologydebate over exactly how photosynthesis manages to be so efficient.
In the case of natural photosynthesis, that charge separation leads to biochemical energy, explains Jennifer Ogilvie,
and use it to generate electricity or some other useable energy source such as biofuels. CHARGE SEPARATION It takes about one-third of a second to blink your eye.
Ogilvie says. e can look at where the energy is transferring and when the charge separation has occurred.
when the gaps in energy level are close to vibrational frequencies, you can have enhanced charge separation,
a critical component of many nuclear power reactors. Production of lithium-7 was banned in the United states due to environmental concerns.
which requires huge amounts of energy to maintain a magnetic field with electromagnets, the new method for enriching stable isotopes, called MAGIS (magnetically activated and guided isotope separation), needs little energy due to its use of low-powered lasers and permanent magnets.
The new method, described in a study published in the journal Nature Physics, also has less potential for environmental effects than the chemical process used in producing lithium-7,
and a disruption could cause the shutdown of reactors. Other isotopes can be used to detect dangerous nuclear materials arriving at US ports.
#Power plant battery uses tanks of water Scientists have created new, water-based organic batteries that are built long-lasting
and from cheap, eco-friendly components. They built the new battery, which uses no metals or toxic materials, for use in power plants,
where it could make the energy grid more resilient and efficient by creating a large-scale way to store energy for use as needed. he batteries last for about 5,
000 recharge cycles, giving them an estimated 15-year life span, says Sri Narayan, professor of chemistry at the University of Southern California and corresponding author of the paper published online in the Journal of the Electrochemical Society. ithium ion batteries degrade after around 1,
000 cycles and cost 10 times more to manufacture. Narayan collaborated with G. K. Surya Prakash,
professor of chemistry and director of the Loker Hydrocarbon Research Institute. uch organic flow batteries will be game-changers for grid electrical energy storage in terms of simplicity, cost, reliability,
and sustainability, Prakash says. Renewable energy The batteries could pave the way for renewable energy sources to make up a greater share of the nation energy generation.
Solar panels can only generate power when the sun shining, and wind turbines can only generate power when the wind blows.
That inherent unreliability makes it difficult for power companies to rely on them to meet customer demand.
With batteries to store surplus energy which can be doled out as needed, that sporadic unreliability could cease to be an issue.?
Mega-scaleenergy storage is a critical problem in the future of renewable energy, Narayan says. The new battery is based on a redox flow designimilar in design to a fuel cell,
with two tanks of electroactive materials dissolved in water. The solutions are pumped into a cell containing a membrane between the two fluids with electrodes on either side releasing energy.
The design has the advantage of decoupling power from energy. The tanks of electroactive materials can be made as large as neededncreasing the total amount of energy the system can storer the central cell can be tweaked to release that energy faster or slower
altering the amount of power (energy released over time) that the system can generate. Nature energy transfer The team breakthrough centered on the electroactive materials.
While previous battery designs have used metals or toxic chemicals, Narayan and Prakash wanted to find an organic compound that could be dissolved in water.
Such a system would create a minimal impact on the environment and would likely be figured cheap,
they. Through a combination of molecule design and trial-and-error, the scientists found that certain naturally occurring quinonesxidized organic compoundsit the bill.
Quinones are found in plants, fungi bacteria, and some animals, and are involved in photosynthesis and cellular respiration. hese are the types of molecules that nature uses for energy transfer,
Narayan says. Currently, the quinones needed for the batteries are manufactured from naturally occurring hydrocarbons. In the future, the potential exists to derive them from carbon dioxide,
Narayan says. The team has filed several patents in regard to the design of the battery and next plans to build a larger-scale version.
The Advanced Research Projects Agency-Energy Open-Funding Opportunity Announcement program, USC, and the Loker Hydrocarbon Research Institute supported the research.
Source: University of Southern Californi U
#Vibrating glove could teach you Braille A new wireless computing glove can help people learn to read
which could make it a much lighter weight replacement for copper transmission lines. In addition, the researchers believe that the material lends itself to many kinds of highly sensitive sensors. e found this graphene oxide fiber was very strong
#Solar cell spikes let in 99%of sunlight The more light absorbed by a solar panel active elements,
A new one-step process to etch nanoscale spikes into silicon lets the maximum amount of sunlight reach a solar cell,
#Can nano dots outshine current solar cells? University of Toronto rightoriginal Studyposted by Marit Mitchell-Toronto on June 9 2014those flat glassy solar panels on your neighborâ#roof may be getting a more efficient makeover thanks to a new class of solar-sensitive nanoparticles.
This new form of solid stable light-sensitive nanoparticles called colloidal quantum dots could lead to cheaper and more flexible solar cells as well as better gas sensors infrared lasers infrared light emitting diodes and more.
The work appearsâ in Nature Materials. Collecting sunlight using these tiny colloidal quantum dots depends on two types of semiconductors:
-and p-type layers simultaneously not only boosts the efficiency of light absorption it opens up a world of new optoelectronic devices that capitalize on the best properties of both light and electricity.
and with this new material we can build new device structuressays Ning odide is almost a perfect ligand for these quantum solar cells with both high efficiency
But improved performance is just a start for the new quantum dot-based solar cell architecture. The powerful little dots could be mixed into inks
and accessibility of solar power for millions of people. he field of colloidal quantum dot photovoltaics requires continued improvement in absolute performance
The material shows promise to replace more costly and energy-intensive processes. Natural gas is the cleanest fossil fuel.
All of this works in ambient temperatures unlike current high-temperature capture technologies that use up a significant portion of the energy being produced.
and this week set new rules to cut carbon pollution from the nation s power plants. ur technique allows one to specifically remove carbon dioxide at the source.
and produces energy as a byproductnd couples that with an ultrafiltration, air stripping, and a reverse osmosis system. f you have 1, 000 cows on your operation,
When light (an electromagnetic field) reflects from a metal mirror it shakes the metal s free electrons (the particles)
and chemical energy in plants and solar cells and in the future it may enable metals to function as active elements in optical communications.
The Division of Chemical sciences Geosciences and Biosciences of the Office of Basic energy Sciences of the US Department of energy supported the work.
A transducer turns one form of energy into another. In this case it turns terahertz light into ultrasound waves
because it responds to the energy of individual terahertz light pulses, rather than a continuous stream of T-rays.
Geobacter removes any waste produced during glycerol fermentation to generate electricity. It is a win-win situation.
These fuel cells do not harvest electricity as an output. Rather, they use a small electrical input platform to generate hydrogen and increase the MEC efficiency even more.
#New battery turns wasted heat into energy Stanford university rightoriginal Studyposted by Dan Stober-Stanford on May 22 2014researchers have developed a new battery technology that captures low-temperature waste heat
and converts it into electricity. Vast amounts of excess heat are generated by industrial processes and by electric power plants.
Researchers have spent decades seeking ways to harness some of this wasted energy. Most such efforts have focused on thermoelectric devicesâ##solid-state materials that can produce electricity from a temperature gradientâ
##but the efficiency of such devices is limited by the availability of materials. Now researchers have found a new alternative for low-temperature waste-heat conversion into electricityâ##that is in cases where temperature differences are less than 100 degrees Celsius.
The researchers describe the approach inâ Nature Communications. irtually all power plants and manufacturing processes like steelmaking
and refining release tremendous amounts of low-grade heat to ambient temperaturessays Yi Cui an associate professor of materials science and engineering at Stanford university. ur new battery technology is designed to take advantage of this temperature gradient at the industrial scale. he new system
is based on the principle known as the thermogalvanic effect which states that the voltage of a rechargeable battery is dependent on temperature. o harvest thermal energy we subject a battery to a four-step process:
heating up charging cooling down and dischargingsays Seok Woo Lee a postdoctoral scholar at Stanford
First an uncharged battery is heated by waste heat. Then while the battery is still warm a voltage is applied.
Once fully charged the battery is allowed to cool. Because of the thermogalvanic effect the voltage increases as the temperature decreases.
When the battery has cooled it actually delivers more electricity than was used to charge it. That extra energy doesn t appear from nowhere explains Cui.
It comes from the heat that was added to the system. The system aims at harvesting heat at temperatures below 100 C which accounts for a major part of potentially harvestable waste heat. ne-third of all energy consumption in the United states ends up as low-grade heatsays co-lead author Yuan
Yang a postdoc at the Massachusetts institute of technology (MIT. In the experiment a battery was heated to 60 C charged and cooled.
The process resulted in an electricity-conversion efficiency of 5. 7 percent almost double the efficiency of conventional thermoelectric devices.
This heating-charging-cooling approach was proposed first in the 1950s at temperatures of 500 C
or more says Yang who notesâ that most heat recovery systems work best with higher temperature differences. key advance is using material that was not around at that timefor the battery electrodes as well as advances in engineering the system says co-author Gang Chen a professor
of mechanical engineering at MIT. his technology has the additional advantage of using low-cost abundant materials
and manufacturing processes that are used already widely in the battery industryadds Lee. While the new system has a significant advantage in energy conversion efficiency over conventional thermoelectric devices it has a much lower power densityâ##that is the amount of power that can be delivered for a given weight.
The new technology also will require further research to assure long-term reliability and improve the speed of battery charging
and discharging Chen adds. t will require a lot of work to take the next step. here is currently no good technology that can make effective use of the relatively low-temperature differences this system can harness Chen says. his has an efficiency we think is quite attractive.
and deployed to use it. he results are very promising says Peidong Yang a professor of chemistry at the University of California Berkeley who was involved not in the study. y exploring the thermogalvanic effect the researchers were able to convert low-grade heat to electricity with decent efficiencyhe says. his is a clever idea
This possibility is one of the reasons for the current interest in building the capacity to store electrical energy directly into a wide range of products such as a laptop
whose casing serves as its battery or an electric car powered by energy stored in its chassis
or a home where the dry wall and siding store the electricity that runs the lights
and appliances. hese devices demonstrateâ##for the first time as far as we can tellâ##that it is possible to create materials that can store
and discharge significant amounts of electricity while they are subject to realistic static loads and dynamic forces such as vibrations or impactssays Cary Pint assistant professor of mechanical engineering at Vanderbilt University.
and Energy Devices Laboratory there. ndrew has managed to make our dream of structural energy storage materials into a realitysays Pint.
which a wide variety of technologies are developed in the future. hen you can integrate energy into the components used to build systems it opens the door to a whole new world of technological possibilities.
The new device that Pint and Westover have developed is a supercapacitor that stores electricity by assembling electrically charged ions on the surface of a porous material instead of storing it in chemical reactions the way batteries do.
and operate for millions of cycles instead of thousands of cycles like batteries. In a paper appearing online in the journal Nano Letters Pint
and releasing electrical charge while subject to stresses or pressures up to 44 psi and vibrational accelerations over 80 g (significantly greater than those acting on turbine blades in a jet engine).
Furthermore the mechanical robustness of the device doesn t compromise its energy storage capability. n an unpackaged structurally integrated state our supercapacitor can store more energy
One area where supercapacitors lag behind batteries is in electrical energy storage capability: Supercaps must be larger and heavier to store the same amount of energy as lithium-ion batteries.
However the difference is not as important when considering multifunctional energy storage systems. attery performance metrics change when you re putting energy storage into heavy materials that are needed already for structural integritysays Pint. upercapacitors store ten times less energy than current lithium-ion batteries
but they can last a thousand times longer. That means they are suited better for structural applications.
Sandwiched between the two electrodes is a polymer film that acts as a reservoir of charged ions similar to the role of the electrolyte paste in a battery.
and solidifies it forms an extremely strong mechanical bond. he biggest problem with designing load-bearing supercaps is preventing them from delaminatingsays Westover. ombining nanoporous material with the polymer electrolyte bonds the layers together tighter than superglue. he use
and solar cells but Pint and Westover are confident that the rules that govern the load-bearing character of their design will carry over to other materials such as carbon nanotubes and lightweight porous metals like aluminum.
The US Department of energy s Advanced Research Project Agency for Energy is investing $8. 7 million in research projects that focus specifically on incorporating energy storage into structural materials.
There have also been recent press reports of several major efforts to develop multifunctional materials or structural batteries for use in electric vehicles and for military applications.
which is supported by the Office of Basic energy Sciences of the US Department of energy. Source: Vanderbilt Universityyou are free to share this article under the Creative Commons Attribution-Noderivs 3. 0 Unported license m
#eurogrid chips mimic the brain to use less energy Compared to the human brain, today computers are ridiculously slow
and take about 40,000 times more power to run. rom a pure energy perspective, the brain is hard to match,
explains Boahen. chieving this level of energy efficiency while offering greater configurability and scale is the ultimate challenge neuromorphic engineers face.
#To save energy, computers go for good enough Purdue University rightoriginal Studyposted by Emil Venere-Purdue on December 23 2013computers capable of pproximate computingcould potentially double efficiency
and reduce energy use. Researchers are developing computers that could perform calculations good enough for certain tasks that don t require perfect accuracy. he need for approximate computing is driven by two factors:
and saps energy. f I asked you to divide 500 by 21 and I asked you
They often compute to the same level of accuracy all the time. urdue researchers have developed a range of hardware techniques to demonstrate approximate computing showing a potential for improvements in energy efficiency.
what we have seen is that we can easily double energy efficiency. n other recent work led by former doctoral student Vinay K. Chippa the Purdue team fabricated an approximate cceleratorfor recognition
As it moves along a carbon-nanotube track it continuously harvests energy from strands of RNA molecules vital to a variety of roles in living cells
and viruses. ur motors extract chemical energy from RNA molecules decorated on the nanotubes and use that energy to fuel autonomous walking along the carbon nanotube trackchoi says.
The core is made of an enzyme that cleaves off part of a strand of RNA. After cleavage the upper DNA arm moves forward binding with the next strand of RNA
flexible batteries made from electrically conductive paper; new drug-delivery technologies; transparent flexible displays for electronic devices; special filters for water purification;
000 LED bulbs by stomping one foot One day it may be possible to harvest the otherwise wasted energy of your footsteps
what s technically known as the triboelectric effect to create surprising amounts of electric power by rubbing or touching two different materials together.
and sensor applicationssays Zhong Lin Wang a professor in the School of Materials science and engineering. his opens up a source of energy by harvesting power from activities of all kinds. n its simplest form the triboelectric generator
Generators producing DC current have also been built. he fact that an electric charge can be produced through triboelectrification is well knownwang explains. hat we have introduced is a gap separation technique that produces a voltage drop
which leads to a current flow in the external load allowing the charge to be used. his generator can convert random mechanical energy from our environment into electric energy. ince their first publication on the research Wang
and his research team have increased the power output density of their triboelectric generator by a factor of 100000â##reporting that a square meter of single-layer material can now produce as much as 300 watts.
The researchers have expanded the range of energy-gathering techniques from ower shirtscontaining pockets of the generating material to shoe inserts whistles foot pedals floor mats backpacks
Their latest paper published in the journal ACS Nano described harvesting energy from the touch pad of a laptop computer.
Beyond its use as a power source Wang is also using the triboelectric effect for sensing without an external power source.
because they re very poor conductors. nter graphene the single-atom-thick sheet of carbon that both conducts electricity and because it s so thin allows radio frequencies to pass unhindered.
and Volman recognized the potential. ristine graphene transmits electricity ballistically and would not produce enough heat to melt ice
Called a near broken-gap tunnel field effect transistor (TFET) the new device uses the quantum mechanical tunneling of electrons through an ultrathin energy barrier to provide high current at low voltage.
The results can be seen in batteries that drain faster and increasing heat dissipation that can damage delicate electronic circuits.
Various new types of transistor architecture using materials other than the standard silicon are being studied to overcome the power consumption challenge. his transistor has previously been developed in our lab to replace MOSFET transistors for logic applications
while draining the battery requires frequent replacement surgery. The researchers led by Suman Datta professor of electrical engineering tuned the material composition of the indium gallium arsenide/gallium arsenide antimony
so that the energy barrier was close to zeroâ##or near broken gap which allowed electrons to tunnel through the barrier when desired.
are combined with the reactive substance a battery-powered handheld reader is used then to detect any fluorescence
Nanostructured metamaterials however are making it possible to reduce the wavelength of light allowing the creation of new types of nanophotonic devices says Vladimir M. Shalaev scientific director of nanophotonics at Purdue s Birck Nanotechnology Center
Under development for about 15 years metamaterials owe their unusual potential to precision design on the scale of nanometers.
We are learning so many rules for calculating things that other people cannot compute in atoms in atomic crystals. he ratio affects the energy of the faces of the crystals
Ratios that don t follow the recipe lead to large fluctuations in energy and result in a sphere not a faceted crystal she explained.
With the correct ratio the energies fluctuate less and result in a crystal every time. magine having a million balls of two colors some red some blue in a container
and energy for all the particles to arrange themselves and find the spots they should be inmirkin says.
when triggered by an external source of energy. However electrons and holes in semiconductors are charged particles
when the so-called Fermi energy is much larger than the thermal energy. When pumped by a strong laser these quantum degenerate particles gathered energy
and released it as light at the Fermi edge: the energy level of the most energetic particles in the system.
As the electrons and holes combined to release photons the edge shifted to lower energy particles
and tested a new approach to cloakingâ##by surrounding an object with small antennas that collectively radiate an electromagnetic field.
instead of surrounding what you re trying to cloak with a thick metamaterial shell we surround it with one layer of tiny antennas
and clunkyâ##if you wanted to cloak a car for example in practice you would have to completely envelop the vehicle in many layers of metamaterials in order to effectively hieldit from electromagnetic radiation.
and processing radio-frequency signals are much harder to miniaturizesays project co-leader Kenneth Shepard an electrical engineering professor. hese off-chip components take up a lot of space and electrical power.
#This is the first battery electrode that heals itself Stanford university rightoriginal Studyposted by Glennda Chui-Stanford on November 19 2013scientists have created the world s first self-healing battery electrode
and say it could open the door to better batteries for phones cars and other gadgets.
and spontaneously heals tiny cracks that develop during battery operation. elf-healing is very important for the survival and long lifetimes of animals
and plantssays Chao Wang a postdoctoral researcher at Stanford university and one of two principal authors of the paper. e want to incorporate this feature into lithium ion batteries
For the battery project Chao added tiny nanoparticles of carbon to the polymer so it would conduct electricity. e found that silicon electrodes lasted 10 times longer
which repaired any cracks within just a few hoursbao says. heir capacity for storing energy is in the practical range now
and from all our data it looks like it s working. esearchers worldwide are racing to find ways to store more energy in the negative electrodes of lithium ion batteries to achieve higher performance while reducing weight.
it has a high capacity for soaking up lithium ions from the battery fluid during charging and then releasing them
when the battery is put to work. But this high capacity comes at a price: silicon electrodes swell to three times their normal size
and shrink back down again each time the battery charges and discharges. The brittle material soon cracks and falls apart degrading battery performance.
This is a problem for all electrodes in high-capacity batteries says Hui Wu a former Stanford postdoc who is now a faculty member at Tsinghua University in Beijing
and the other principal author of the paper. To make the self-healing coating scientists deliberately weakened some of the chemical bonds within polymersâ â##long chainlike molecules with many identical units.
The resulting material breaks easily but the broken ends are drawn chemically to each other and quickly link up again mimicking the process that allows biological molecules such as DNA to assemble rearrange and break down.
Researchers in Cui s lab and elsewhere have tested a number of ways to keep silicon electrodes intact
and solar cell industry is the first solution that seems to offer a practical road forward Cui says.
and the Precourt Institute for Energy at Stanford funded the work. Source: Stanford Universityyou are free to share this article under the Creative Commons Attribution-Noderivs 3. 0 Unported license
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