#EEG reveals image in short-term memory Researchers have tapped the rhythm of memories as they occur in near real time in the human brain.
Using electroencephalogram (EEG) electrodes attached to the scalps of 25 student subjects, a team led by University of Oregon psychology doctoral student David E. Anderson captured synchronized neural activity
while they held a simple oriented bar located within a circle in short-term memory. The team, by monitoring these alpha rhythms,
says Edward Awh, a professor in the department of psychology and Institute of Neuroscience. The new findings show that EEG measures of synchronized neural activity can precisely track the contents of memory at almost the speed of thought,
he says. hese findings provide strong evidence that these electrical oscillations in the alpha frequency band play a key role in a person ability to store a limited number of items in working memory,
wee getting closer to understanding the low-level building blocks of this really limited cognitive ability. If this rhythm is
Past work, mainly using functional magnetic resonance imaging (fmri), has established that brain activity can track the content of memory.
EEG, however, provides a much less expensive approach and can track mental activity with much a higher temporal resolution of about one-tenth of a second compared to about five seconds with fmri. ith EEG we get a fine-grained measure of the precise contents of memory,
while benefitting from the superior temporal resolution of electrophysiological measures, Awh says. his EEG approach is a powerful new tool for tracking
and decoding mental representations with high temporal resolution. It should provide us with new insights into how rhythmic brain activity supports core memory processes.
The NIH National institute of mental health funded the research. John T. Serences of the University of California, San diego, also was a coauthor of the study l
#System turns cow poop into clean water Scientists are developing a system that can take cow manure
and turn it into water that is clean enough for livestock to drink. It also extracts nutrients that can be reused as fertilizer.
Currently the system produces about 50 gallons of water from 100 gallons of manure. The goal is to increase that number to about 65 gallons.
It works by taking an anaerobic digester contraption that takes waste such as manure, 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, they produce about 10 million gallons of manure a year,
says Steve Safferman, an associate professor of biosystems and agricultural engineering at Michigan State university, who is involved with the project. bout 90 percent of the manure is water
and pathogens that can have an environmental impact if not properly managed. While turning the manure into clean water makes environmental sense
the team also is conducting research on how it can make good financial sense for farmers.
The process oes beyond a typical digester, explains Jim Wallace, a former graduate student at Michigan State who now works for the Mclanahan Corp.
It does this by extracting nutrients from the manure that can be harmful to the environment
and can be reused as fertilizer . or example, wee able to capture a large percentage of the ammonia that would otherwise be lost in the atmosphere,
#Scientists are first to detect exciton in metals University of Pittsburgh rightoriginal Studyposted by Joe Miksch-Pittsburgh on June 2 2014humans have used reflection of light from a metal mirror on a daily basis for thousands of years
For the first time researchers have detected the exciton a fundamental particle of light-matter interaction in metals. Physicists describe physical phenomena in terms of interactions between fields
and particles says lead author Hrvoje Petek professor in the physics and astronomy department at the University of Pittsburgh.
When light (an electromagnetic field) reflects from a metal mirror it shakes the metal s free electrons (the particles)
The classical theory of electromagnetism provides a good understanding of inputs and outputs of this process but a microscopic quantum mechanical description of how the light excites the electrons is lacking.
Petek s team of experimental and theoretical physicists and chemists from the University of Pittsburgh and Institute of Physics in Zagreb Croatia report on how light
and matter interact at the surface of a silver crystal. They observe for the first time an exciton in a metal.
Excitons particles of light-matter interaction where light photons become transiently entangled with electrons in molecules
and semiconductors are known to be fundamentally important in processes such as plant photosynthesis and optical communications that are the basis for the internet and cable TV.
The optical and electronic properties of metals cause excitons to last no longer than approximately 100 attoseconds (0. 1 quadrillionth of a second.
Such short lifetimes make it difficult for scientists to study excitons in metals but it also enables reflected light to be a nearly perfect replica of the incoming light.
Yet Branko Gumhalter at the Institute of Physics predicted and Petek and his team experimentally discovered that the surface electrons of silver crystals can maintain the excitonic state more than 100 times longer than the bulk metal enabling the excitons in metals to be captured experimentally by a newly developed multidimensional coherent spectroscopic technique.
The ability to detect excitons in metals sheds light on how light is converted to electrical
and chemical energy in plants and solar cells and in the future it may enable metals to function as active elements in optical communications.
In other words it may be possible to control how light is reflected from a metal. The paper appears online in Nature Physics.
The Division of Chemical sciences Geosciences and Biosciences of the Office of Basic energy Sciences of the US Department of energy supported the work.
Source: University of Pittsburghyou are free to share this article under the Creative Commons Attribution-Noderivs 3. 0 Unported license e
#Tiny device detects terahertz light in real time Engineers have created a device that detects terahertz frequencies by converting them into sound waves
and then transmitting them. Terahertz light is not visible to humans, and scientists have struggled to develop a practical way to detect it.
Current detectors are need bulky and to be kept cold to operate. That limits their usefulness for applications like weapons and chemical detection and medical imaging and diagnosis, says Jay Guo,
an engineering professor at the University of Michigan. ur detector is sensitive, compact and works at room temperature,
and wee made it using an unconventional approach. Guo and colleagues invented a special transducer that makes the light-to-sound conversion possible.
A transducer turns one form of energy into another. In this case it turns terahertz light into ultrasound waves
The transducer is made of a mixture of a spongy plastic called polydimethylsiloxane, or PDMS, and carbon nanotubes.
HOW IT WORKS When the terahertz light hits the transducer, the nanotubes absorb it, turning it into heat.
They pass that heat on to the PDMS. The heated PDMS expands, creating an outgoing pressure wave.
Though ultrasound detectors existncluding those used in medical imaginghe researchers made their own sensitive one in the form of a microscopic plastic ring known as a microring resonator.
They connected their system to a computer and demonstrated that they could use it to scan
The response speed of the new detector is a fraction of a millionth of a second,
because it responds to the energy of individual terahertz light pulses, rather than a continuous stream of T-rays.
The National Science Foundation and the Air force Office of Scientific research funded the work e
#Extra-hairy microbes make biodiesel sustainable With the help of Geobacter microbes, biodiesel plants may be able to stop creating hazardous wastes
and eliminate fossil fuel from their production process. The platform, which uses microbes to glean ethanol from glycerol
and the water into the fuel-making process, says Gemma Reguera, Michigan State university microbiologist and one of the study coauthors. ith a saturated glycerol market,
traditional approaches see producers pay hefty fees to have hauled toxic wastewater off to treatment plants,
At the same time, they are taking care of their hazardous waste problem. AIRYBACTERIA The results, which appear in the journal Environmental science
and Technology, show that the key to Reguera platform is patented her adaptive-engineered bacteriaeobacter sulfurreducens.
Much of Reguera research with these bacteria focuses on engineering their conductive pili or nanowires.
Reguera, along with lead authors and graduate students Allison Speers and Jenna Young, evolved Geobacter to withstand increasing amounts of toxic glycerol.
and eliminate all of the waste. Together, the bacteria appetite for the toxic byproducts is inexhaustible. hey feast like theye at a Las vegas buffet
she adds. ne bacterium ferments the glycerol waste to produce bioethanol, which can be reused to make biodiesel from oil feedstocks.
Geobacter removes any waste produced during glycerol fermentation to generate electricity. It is a win-win situation.
The hungry microbes are featured the component of Reguera microbial electrolysis cells, or MECS. 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
and co-lead author of the study. 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.
There is so much of this low-temperature waste heat if a technology can be created 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
and low-grade waste heat is everywhere. ther authors of the study are Hyun-Wook Lee of Stanford and Hadi Ghasemi and Daniel Kraemer of MIT.
#Can supercapacitor wafers make power cords obsolete? Vanderbilt University rightoriginal Studyposted by David Salisbury-VU on May 22 2014imagine a future in which plugs and external power sources no longer limit our electrical gadgets.
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.
He and graduate student Andrew Westover have built small aferdevices in the Nanomaterials and Energy Devices Laboratory there. ndrew has managed to make our dream of structural energy storage materials into a realitysays Pint.
That is important because structural energy storage will change the way in 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.
All of a sudden the ability to design technologies at the basis of health entertainment travel and social communication will not be limited by plugs
and external power sourcespint says. 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.
As a result supercaps can charge and discharge in minutes instead of hours 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 Westover report that their new structural supercapacitor operates flawlessly in storing
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
and operate at higher voltages than a packaged off-the-shelf commercial supercapacitor even under intense dynamic
and static forcespint says. 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.
It doesn t make sense to develop materials to build a home car chassis or aerospace vehicle if you have to replace them every few years
because they go dead. estover s wafers consist of electrodes made from silicon that have been treated chemically so they have nanoscale pores on their inner surfaces
and then coated with a protective ultrathin graphene-like layer of carbon. 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.
When the electrodes are pressed together the polymer oozes into the tiny pores in much the same way that melted cheese soaks into the nooks and crannies of the bread in a panini.
When the polymer cools 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
of silicon in structural supercapacitors is suited best for consumer electronics 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 intensity of interest in ultifunctionaldevices of this sort is clear: 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.
However Pint points out that there have not been any reports in the technical literature of tests performed on structural energy storage materials that show how they function under realistic mechanical loads.
The National Science Foundation supported the work. Materials fabrication took place in part at the Center for Nanophase Materials sciences at Oak ridge National Laboratory
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
#Cheaper membrane filters natural gas and oil Engineers have developed a new gas separation membrane that could make extracting impurities from oil and natural gases easier and less expensive.
Jaime C. Grunlan and Benjamin A. Wilhite of Texas A&m University report the findings in Advanced Materials.
They have filed also a patent for this technology due to its commercial potential. e use a simple polymer-based film to remove the impurities
and it has the promise of a less expensive method for producing purer oil, says Wilhite,
associate professor in the department of chemical engineering. t is all polymer and we are able to get performances comparable to really expensive materials such as mixed matrix membranes
and zeolites. he technology is separating gases, adds Grunlan, associate professor in the mechanical engineering department. as where they mine it is impure
and contains different poison gases you don want. If you run gas through this membrane what comes out is much purer than
what went in on the other side. The membrane that Grunlan and Wilhite have developed is a layer-by-layer polymer coating that is comprised of alternating individual layers of common, low-cost polyelectrolytes.
The coating can be made by dipping or spraying, making it very easy to apply to existing gas separation systems.
These films separate molecules based on size the smaller ones such as hydrogen pass through, while larger ones such as carbon dioxide and nitrogen are slowed down. ou can have multiple membranes in a row
and it would keep getting purer and purer each time it went through the membranes, says Grunlan. xcept for a sheet of metal,
nothing has higher selectivity than our coating. This cheap easy coating is the best thing after a pure sheet of metal.
#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,
says Kwabena Boahen, associate professor of bioengineering at Stanford university. Boahen and his team have developed a circuit board consisting of 16 custom-designed eurocorechips.
Together these 16 chips can simulate 1 million neurons and billions of synaptic connections. The team designed these chips with power efficiency in mind.
Their strategy was to enable certain synapses to share hardware circuits. The result was called a device Neurogrid.
It about the size of an ipad and can simulate many more neurons and synapses than other brain mimicking devices using only about the power it takes to run a tablet computer.
But it still a power hog compared to the brain. he human brain, with 80,000 times more neurons than Neurogrid, consumes only three times as much power,
explains Boahen. chieving this level of energy efficiency while offering greater configurability and scale is the ultimate challenge neuromorphic engineers face.
Comparison aside, Neurogrid speed and low power characteristics make it ideal for more than just modeling the human brain.
Boahen is working with other Stanford scientists to develop prosthetic limbs for paralyzed people that would be controlled by a Neurocore-like chip. ight now
you have to know how the brain works to program one of these, says Boahen, gesturing at the $40,
000 prototype board on the desk of his office. e want to create a neurocompiler so that you would not need to know anything about synapses
which aims to simulate a human brain on a supercomputer. By contrast the US BRAIN Projecthort for Brain Research through Advancing Innovative Neurotechnologiesas taken a tool-building approach by challenging scientists to develop new kinds of tools that can read out the activity of thousands
Zooming from the big picture, Boahen article focuses on two projects comparable to Neurogrid that attempt to model brain functions in silicon and/or software.
IBM OLDEN GATECHIP One of these efforts is IBM Synapse Projecthort for Systems of Neuromorphic Adaptive Plastic Scalable Electronics.
Synapse involves a bid to redesign chips, code-named Golden gate, to emulate the ability of neurons to make a great many synaptic connections feature that helps the brain solve problems on the fly.
with IBM on track to greatly increase the numbers of neurons in the system. HICANN CHIP FOR BRAIN SIMULATORS Heidelberg University Brainscales project has the ambitious goal of developing analog chips to mimic the behaviors of neurons and synapses.
Their HICANN chiphort for High Input Count Analog Neural Networkould be the core of a system designed to accelerate brain simulations
to enable researchers to model drug interactions that might take months to play out in a compressed time frame.
with a roadmap to greatly expand that hardware base. Each of these research teams has made different technical choices,
such as whether to dedicate each hardware circuit to modeling a single neural element (e g.,, a single synapse) or several (e g.,
, by activating the hardware circuit twice to model the effect of two active synapses. These choices have resulted in different trade-offs in terms of capability and performance.
In his analysis, Boahen creates a single metric to account for total system costncluding the size of the chip,
LOWER COST FROM $40, 000 TO $400 But much work lies ahead. Each of the current million-neuron Neurogrid circuit boards cost about $40
000. Boahen believes dramatic cost reductions are possible. Neurogrid is based on 16 Neurocores, each of which supports 65,536 neurons.
Those chips were made using 15-year-old fabrication technologies. By switching to modern manufacturing processes
and fabricating the chips in large volumes, he could cut a Neurocore cost 100-folduggesting a million-neuron board for $400 a copy.
With that cheaper hardware and compiler software to make it easy to configure, these neuromorphic systems could find numerous applications.
For instance, a chip as fast and efficient as the human brain could drive prosthetic limbs with the speed
#Small tuning fork lets device find greenhouse gas Scientists have created a highly sensitive portable sensor to test the air for the most damaging greenhouse gases.
invented at Rice university in 2002 by engineer Frank Tittel, Professor Robert Curl, and their collaborators, offers the possibility that such devices may soon be as small as a typical smartphone.
Tittel team tested the small device at a Houston dump and found it capable of detecting trace amounts of methane3 parts per billion by volume (ppbv) nd nitrous oxide ppbv. ethane
professor of electrical and computer engineering and a professor of bioengineering. ethane is emitted by natural sources, such as wetlands,
and human activities, such as leakage from natural gas systems and the raising of livestock. uman activities such as agriculture, fossil fuel combustion, wastewater management,
greater compared with the most prevalent greenhouse gas, carbon dioxide, over a 100-year period. For these reasons, methane and nitrous oxide detection is crucial to environmental considerations.
QUARTZ TUNING FORK The small QCL has only become available in recent years, Tittel says, and is far better able to detect trace amounts of gas than lasers used in the past.
What makes the technique possible is the small quartz tuning fork, which vibrates at a specific frequency
The laser beam is focused between the two prongs of the quartz tuning fork. When light at a specific wavelength is absorbed by the gas of interest
and that excites the quartz tuning fork. he tuning fork is a piezoelectric element, so when the wave causes it to vibrate,
the team installed it on a mobile laboratory used during NASA DISCOVER-AQ campaign, which analyzed pollution on the ground and from the air last September.
and the QEPAS sensor findings compared favorably with the lab much larger instrument, Tittel says. his was a milestone for trace-gas sensing,
Tittel says a smaller QEPAS device will be added this year to the mobile monitoring van currently carrying out a Rice university of Houston survey of pollutants in the city.
Overtext Web Module V3.0 Alpha
Copyright Semantic-Knowledge, 1994-2011