Electricity collected from the air could become the newest alternative energy source

Imagine devices that capture electricity from the air ― much
like solar cells capture sunlight ― and using them to light a house or
recharge an electric car. Imagine using similar panels on the rooftops of buildings to prevent lightning before it forms. Strange as it may
sound, scientists already are in the early stages of developing such
devices, according to a report presented today at the 240th National
Meeting of the American Chemical Society (ACS).

"Our research could pave the way for turning electricity from the
atmosphere into an alternative energy source for the future," said study
leader Fernando Galembeck, Ph.D. His research may help explain a
200-year-old scientific riddle about how electricity is produced and
discharged in the atmosphere. "Just as solar energy could free some
households from paying electric bills, this promising new energy source
could have a similar effect," he maintained.
"If we know how electricity builds up and spreads in the atmosphere,
we can also prevent death and damage caused by lightning strikes,"
Galembeck said, noting that lightning causes thousands of deaths and
injuries worldwide and millions of dollars in property damage.
The notion of harnessing the power of electricity formed naturally
has tantalized scientists for centuries. They noticed that sparks of
static electricity formed as steam escaped from boilers. Workers who
touched the steam even got painful electrical shocks. Famed inventor
Nikola Tesla, for example, was among those who dreamed of capturing and
using electricity from the air. It's the electricity formed, for
instance, when water vapor collects on microscopic particles of dust and
other material in the air. But until now, scientists lacked adequate
knowledge about the processes involved in formation and release of
electricity from water in the atmosphere, Galembeck said. He is with the
University of Campinas in Campinas, SP, Brazil.
Scientists once believed that water droplets in the atmosphere were
electrically neutral, and remained so even after coming into contact
with the electrical charges on dust particles and droplets of other
liquids. But new evidence suggested that water in the atmosphere really
does pick up an electrical charge.

Galembeck and colleagues confirmed that idea, using laboratory
experiments that simulated water's contact with dust particles in the
air. They used tiny particles of silica and aluminum phosphate, both
common airborne substances, showing that silica became more negatively
charged in the presence of high humidity and aluminum phosphate became
more positively charged. High humidity means high levels of water vapor
in the air ― the vapor that condenses and becomes visible as "fog" on
windows of air-conditioned cars and buildings on steamy summer days.
"This was clear evidence that water in the atmosphere can accumulate
electrical charges and transfer them to other materials it comes into
contact with," Galembeck explained. "We are calling this
'hygroelectricity,' meaning 'humidity electricity'."
In the future, he added, it may be possible to develop collectors,
similar to the solar cells that collect the sunlight to produce
electricity, to capture hygroelectricity and route it to homes and
businesses. Just as solar cells work best in sunny areas of the world,
hygroelectrical panels would work more efficiently in areas with high
humidity, such as the northeastern and southeastern United States and
the humid tropics.

Galembeck said that a similar approach might help prevent lightning
from forming and striking. He envisioned placing hygroelectrical panels
on top of buildings in regions that experience frequent thunderstorms.
The panels would drain electricity out of the air, and prevent the
building of electrical charge that is released in lightning. His
research group already is testing metals to identify those with the
greatest potential for use in capturing atmospheric electricity and preventing lightning strikes.
"These are fascinating ideas that new studies by ourselves and by
other scientific teams suggest are now possible," Galembeck said. "We
certainly have a long way to go. But the benefits in the long range of
harnessing hygroelectricity could be substantial."

http://www.physorg.com/news201958072.html

Graphene may hold key to speeding up DNA sequencing

Extremely thin membrane, a mere one-atom thick, lives up to its acclaim as a 'rapidly rising star'

Cambridge, Mass. - September 9, 2010 - In a paper published as the cover story of the September 9, 2010 Nature,
researchers from Harvard University and MIT have demonstrated that
graphene, a surprisingly robust planar sheet of carbon just one-atom
thick, can act as an artificial membrane separating two liquid
reservoirs.
By drilling a tiny pore just a few-nanometers in diameter, called a
nanopore, in the graphene membrane, they were able to measure exchange
of ions through the pore and demonstrated that a long DNA molecule can
be pulled through the graphene nanopore just as a thread is pulled
through the eye of a needle.

"By measuring the flow of ions passing through a nanopore drilled in
graphene we have demonstrated that the thickness of graphene immersed in
liquid is less then 1 nm thick, or many times thinner than the very
thin membrane which separates a single animal or human cell from its
surrounding environment," says lead author Slaven Garaj, a Research
Associate in the Department of Physics at Harvard. "This makes graphene
the thinnest membrane able to separate two liquid compartments from each
other. The thickness of the membrane was determined by its interaction
with water molecules and ions."
Graphene, the strongest material known, has other advantages. Most importantly, it is electrically conductive.

"Although the membrane prevents ions and water from flowing through
it, the graphene membrane can attract different ions and other chemicals
to its two atomically close surfaces. This affects graphene's
electrical conductivity and could be used for chemical sensing," says
co-author Jene Golovchenko, Rumford Professor of Physics and Gordon
McKay Professor of Applied Physics at Harvard, whose pioneering work
started the field of artificial nanopores in solid-state membranes.
"I believe the atomic thickness of the graphene makes it a novel
electrical device that will offer new insights into the physics of
surface processes and lead to a wide range of practical application,
including chemical sensing and detection of single molecules."

In recent years graphene has astonished the scientific community with
its many unique properties and potential applications, ranging from
electronics and solar energy research to medical applications.
Jing Kong, also a co-author on the paper, and her colleagues at MIT
first developed a method for the large-scale growth of graphene films
that was used in the work.
The graphene was stretched over a silicon-based frame, and inserted
between two separate liquid reservoirs. An electrical voltage applied
between the reservoirs pushed the ions towards graphene membrane. When a
nanopore was drilled through the membrane, this voltage channeled the
flow of ions through the pore and registered as an electrical current
signal.

When the researchers added long DNA chains in the liquid, they were
electrically pulled one by one through the graphene nanopore. As the DNA
molecule threads the nanopore, it blocks the flow of ions, resulting in
a characteristic electrical signal that reflects the size and
conformation of the DNA molecule.
Co-author Daniel Branton, Higgins Professor of Biology, Emeritus at
Harvard, is one of the researches who, more than a decade ago, initiated
the use of nanopores in artificial membranes to detect and characterize
single molecules of DNA.
Together with his colleague David Deamer at the University of
California, Branton suggested that nanopores might be used to quickly
read the genetic code, much as one reads the data from a ticker-tape
machine.

As a DNA chain passes through the nanopore, the nucleobases, which
are the letters of the genetic code, can be identified. But a nanopore
in graphene is the first nanopore short enough to distinguish between
two closely neighboring nucleobases.
Several challenges still remain to be overcome before a nanopore can
do such reading, including controlling the speed with which DNA threads
through the nanopore.
When achieved, nanopore sequencing could lead to very inexpensive
and rapid DNA sequencing and has potential to advance personalized
health care.

"We were the first to demonstrate DNA translocation through a truly
atomically thin membrane. The unique thickness of the graphene might
bring the dream of truly inexpensive sequencing closer to reality. The
research to come will be very exciting," concludes Branton.

http://www.eurekalert.org/pub_releases/2010-09/hu-gmh091010.php

 

Astronomers to detect alien volcanoes

SYDNEY: Astronomers may soon be able to detect volcanic activity on
planets outside our Solar System, providing further insight into
‘Earth-like’ alien worlds, according to a recent paper.

When large, explosive volcanic eruptions occur, they emit high
quantities of sulphur dioxide into the stratosphere. Without an
eruption, however, sulphur dioxide only occurs in an Earth-like
stratosphere in very small amounts.
Now scientists have developed a model for eruptions on an Earth-like
exoplanet, finding that the presence of volcanic sulphur dioxide could
be used to remotely detect a volcanic eruption, despite the fact that
technology for imaging the surface of an exoplanet remains decades away.

Catching that first glimpse
“Measuring volcanic activity can be just one new tool in our
near-term toolbox, along with atmospheric spectra, to get an early
‘first glimpse’ into a planet's behaviour, long before we can see
anything like the pattern of oceans, mountain ranges, islands, or
continents,” said co-author, Lisa Kaltenegger, from the
Harvard-Smithsonian Centre for Astrophysics in Boston, Massachusetts.
To look for volcanic sulphur dioxide, astronomers would rely on a
technique known as the secondary eclipse, which requires the exoplanet
to cross behind its star, as seen from Earth.

By collecting light from the star and planet, then subtracting it from
the star (while the planet is hidden), astronomers are left with the
signal from the planet alone. They can then search that signal for signs
of particular chemical molecules.

Finding planets like our own
“If we can find volcanoes on other planets, we can figure out if they
are similar to our own planet when it was young,” said Kaltenegger.
“Or, if [the exoplanet] is as old as the Earth, but still has huge
volcanoes, the question would be, why is that so? What makes that
‘Earth’ different from ours?”
Scientists think that the Earth was much more volcanic when it was
‘young’, and that this helped bring the temperature into a habitable
range.

NASA to test theory
Brad Carter from the University of Southern Queensland said the paper
presents a useful method for studying or detecting terrestrial planets
orbiting “even nearby” stars.
“Given the important role of volcanism in the development of Earth's
atmosphere and climate, this paper suggests a practical new way to
compare rocky extrasolar planets with our own world,” said Carter.
“The line of research taken in this paper suggests an extension of
the method of 'comparative planetology' that has already been successful
in understanding the worlds of our Solar System using comparisons of
different planets," he said.
Kaltenegger hopes to test the theory, and several others, when NASA launches the James Webb Space Telescope (JWST) in 2014.

New microscope breaks light microscopy resolution barrier

A new laser-equipped microscope at IU Bloomington's
Light Microscopy Imaging Center makes it possible to examine biological samples with unprecedented detail in three dimensions.


The $1.2 million DeltaVision OMX super-resolution
microscope from Applied Precision (Issaquah, Wash.) was paid for
entirely with funds from the American Recovery and Reinvestment Act of
2009, through a National Institutes of Health program that supports
high-end instrumentation at America's most deserving centers of higher
education.

"It's a fantastic and unique acquisition for our university," said cell
biologist Claire Walczak, the Imaging Center's executive director. "This
super-resolution microscope, one of only 16 in the world and one of
only 8 commercial units, is part of our vision to bring state-of-the-art
technology to IU's life science researchers, to enable them to address
questions that they did not have the ability to ask previously, due to
the lack of appropriate technologies."

Walczak is a professor of biochemistry and molecular biology in the
Medical Sciences Program Bloomington, an arm of the IU School of
Medicine. Walczak also holds an adjunct appointment in the IU
Bloomington Department of Biology and is part of the Biochemistry
Program.
The imager is exceptionally fast in collecting images of a biological
specimen, and this speed enables scientists to gather crucial data. The
device uses laser light of four different colors to illuminate samples,
while four extremely sensitive digital cameras capture images every 10
milliseconds at the imager's speediest setting. The device can produce
as many as 5,000 full-color images per minute for its major task of
producing high-resolution images. Known as a "structured illumination"
microscope, the device will help IU scientists attain a better
understanding of how proteins are distributed inside cells with
unprecedented resolution.

Most high-technology light microscopes reach the limits of resolution
at 250-300 nanometers -- the diameter of a small bacterial cell. The
new OMX microscope IU has acquired can produce clear images down to 100
nanometers in the lateral dimension. Resolution along the z-axis
(perpendicular, or coming out of the page) is somewhat lower but still
tremendously improved relative to previous technologies.
"We'd envisioned this device would be most useful for
microbiologists, cell biologists, and neurobiologists at IU," Walczak
said. "But we expect scientists from many other fields will come up with
creative ways to take advantage of it."

Light Microscopy
Imaging Center (LMIC) Manager Jim Powers is responsible for training IU
researchers -- as well as visitors -- to use the device.
"The Imaging Center is a user-oriented resource," Powers said.
"Scientists rent time on our devices, and receive training to use them,
but after that, we expect they'll be able to work independently."

IU scientists get a reduced rate when using the LMIC's many microscopes,
due to the generous support from OVPR, the College of Arts and
Sciences, Medical Sciences, and Optometry. At present, the OMX is still
in a training mode in which Powers is working closely with Sid Shaw, an
assistant professor of biology and the technical director of the LMIC,
as well as IU research staff to calibrate the device and establish
protocols for future, similar uses. The LMIC staff expects the
instrument to be available to all IU researchers by September.

The arrival of the DeltaVision OMX microscope has spurred Walczak,
Shaw, and Powers to consider LMIC's future needs. Partly because of the
DeltaVision OMX's size, the LMIC is now out of physical space. In
addition, the device produces so much data (4,000 images takes up about
1.5 gigabytes of hard drive space), Walczak and Powers said one of the
center's next priorities is to improve the center's information
technology infrastructure through continued collaboration with IU's
Information Technology Services. Walczak and Powers want to ensure that
the large data sets produced by the OMX imager can be stored rapidly --
as well as protected from power outages and other catastrophes.


"We have some new things to think about, and lots of new things to see," Walczak said.

International research team develops ultrahigh-power energy storage devices

A team of researchers from the U.S. and France report the development of a micro-supercapacitor with remarkable properties.
The paper was published in the premier scientific journal Nature Nanotechnology online on August 15.

These micro-supercapacitors have the potential to power
nomad electronics, wireless sensor networks, biomedical implants, active
radiofrequency identification (RFID) tags and embedded microsensors,
among other devices.
Supercapacitors, also called electric double layer capacitors (EDLCs)
or ultracapacitors, bridge the gap between batteries, which offer high
energy densities but are slow, and “conventional” electrolytic
capacitors, which are fast but have low energy densities.

The newly developed devices described in Nature Nanotechnology have
powers per volume that are comparable to electrolytic capacitors,
capacitances that are four orders of magnitude higher, and energies per
volume that are an order of magnitude higher. They were also found to be
three orders of magnitude faster than conventional supercapacitors,
which are used in backup power supplies, wind power generators and other
machinery.

These new devices have been dubbed “micro-supercapacitors”
because they are only a few micrometers (0.000001 meters) thick.
What makes this possible? “Supercapacitors store energy in layers of
ions at high surface area electrodes,” said Dr. Yury Gogotsi, Trustee
Chair Professor of materials science and engineering at Drexel
University, and a co-author of the paper. “The higher the surface area
per volume of the electrode material, the better the performance of the
supercapacitor.”

Vadym Mochalin, research assistant professor of materials science and
engineering at Drexel and co-author, said, “We use electrodes made of
onion-like carbon, a material in which each individual particle is made
up of concentric spheres of carbon atoms, similar to the layers of an onion. Each particle is 6-7 nanometers in diameter.”
This is the first time a material with very small spherical particles
has been studied for this purpose. Previously investigated materials
include activated carbon, nanotubes, and carbide-derived carbon (CDC).


“The surface of the onion-like carbons is fully accessible to ions,
whereas with some other materials, the size or shape of the pores or of
the particles themselves would slow down the charging or discharging
process,” Mochalin said. “Furthermore, we used a process to assemble the
devices that did not require a polymer binder material to hold the
electrodes together, which further improved the electrode conductivity
and the charge/discharge rate. Therefore, our supercapacitors can
deliver power in milliseconds, much faster than any battery or supercapacitor used today.”

Researchers make magnetic fields breakthrough

Researchers at the University of Dundee
have made a breakthrough in the study of magnetic fields, which enhances
our understanding of how stars, including the Sun, work.

The team from the Magnetohydrodynamics research group in
the School of Engineering, Physics and Mathematics used state-of-the-art
computer simulations of evolving plasmas in the Sun's atmosphere.

By following how the magnetic field and the plasma interact, they
have uncovered new rules that govern what evolutions are possible.
Knowing the basic rules behind the apparently complex solar atmosphere gives the team hope of predicting how it will behave.
Magnetic fields cannot be directly seen, felt or tasted, but they are
a ubiquitous force of nature.
 

The neat pattern of magnetic "field
lines" from a bar magnet is well-known from school physics experiments.
Indeed, the magnetic field of the Earth itself has a similar pattern on a
much larger scale, which is what enables navigation by compass.
But magnetic fields are not always so ordered. Telescopic pictures of
the Sun's lower atmosphere taken in extreme-ultraviolet light, outside
the visible spectrum,
reveal the shape of the magnetic field lines because the plasma
particles emitting the light are guided by magnetic forces and move
along the magnetic field lines.


These images often reveal braiding and tangling of the field, in a
manner that would render a compass useless. The fact that the magnetic
field lines are tangled like spaghetti means that the plasma in the
Sun's atmosphere is not free to move around however it pleases and that
vast quantities of energy can be locked in the magnetic field, because
tangled fields have more energy than ordered fields.
Scientists believe that this energy is responsible for heating the Sun’s atmosphere to million-degree temperatures, but how this works in detail is a longstanding puzzle in solar physics.

The Dundee team hope their discovery will give us a better idea of just how this energy is released.
'Using these computer simulations,
we have studied braided magnetic fields and made a significant advance
in understanding how they evolve over time,' said Dr Gunnar Hornig, one
of the paper’s authors.

'You can observe magnetic fields on the Sun with satellites and see
that these structures are often braided. That is they are not just
simple loops, but these loops interlink.
'These structures are not static. They evolve because the Sun is not a
rigid body but essentially a plasma ball of gas. It kind of boils, and
the motion on the surface changes these magnetic structures. They start
to move them around and sometimes the braiding is increased. And if
certain critical conditions are met then these structures start to relax
to something simpler.

'If you take a twig of a branch and start to twist it, then at some
point it starts to break and the individual fibres break up. Something
similar happens to these magnetic fields. Where it differs is that the
evolutions we have been studying allow the broken fields to combine to
form new structures.'
Having investigated how magnetic field
braiding works in a specific instance, the team will now switch their
attention to examining how they work in more general, complex
structures.


'We began by looking at braided magnetic fields in the Sun’s
atmosphere,' explained Dr Anthony Yeates, one of the team members. 'We
know that these magnetic fields break up and reconnect and we have now
discovered new rules governing which evolutions are possible and how
this is happening.
'This is fundamental research - part of the theory of astrophysical
plasmas. It forms part of our attempts to understand how stars work,
which enhances our understanding of how our own Sun evolves, and how it
affects the climate and life on Earth.'


Their research has been published in the latest edition of Physical Review Letters, as a paper entitled 'Topological constraints on magnetic relaxation'.
The ongoing research project on quantifying magnetic fluxes started
last October, and is funded by the Science and Technology Facilities
Council.

Scientists discover first new chlorophyll in 60 years

University of Sydney scientists have
stumbled upon the first new chlorophyll to be discovered in over 60
years and have published their findings in the international journal Science.
Found by accident in stromatolites from Western Australia's Shark Bay, the new pigment named chlorophyll f can utilise lower light energy than any other known chlorophyll.

The historic study published online in Science, challenges our
understanding of the physical limits of photosynthesis - revealing that
small-scale molecular changes to the structure of chlorophyll allows
photosynthetic organisms to survive in almost any environment on Earth.


The new chlorophyll was discovered deep within stromatolites -
rock-like structures built by photosynthetic bacteria, called
cyanobacteria - by lead author Dr Min Chen from the University of
Sydney.

A team of interdisciplinary scientists, including Dr Martin Schliep
and Dr Zhengli Cai (University of Sydney); Associate Professor Robert
Willows (Macquarie University); Professor Brett Neilan (University of
New South Wales) and Professor Hugo Scheer (University of Munich),
characterised the absorption properties and chemical structure of chlorophyll f, making it the fifth known type of chlorophyll molecule on Earth.


Chlorophyll is the essential molecule in oxygenic photosynthesis -
the process that enables plants, algae and some bacteria to convert
carbon dioxide into sugar and oxygen by using free energy from sunlight.
Until recently, oxygenic photosynthesis was thought only to occur in
light that is visible to human eyes, between 400nm to 700nm, as
chlorophyll was strictly limited to absorbing light in this range.

This was overturned in 1996 when scientists found a cyanobacterium
that could photosynthesise using light just outside the visible
spectrum - at 710nm, in the infrared region - using a modified
chlorophyll molecule, named chlorophyll d. Since this discovery, scientists around the world have been puzzled by how chlorophyll d is able to get enough energy from infrared light for photosynthesis.
Now the rules of photosynthesis need to be rewritten again, with the
discovery of a new chlorophyll that can absorb light of even lower
photon energy - 720nm - making it the most red-shifted chlorophyll to
date.

In ecological terms, chlorophyll f allows cyanobacteria living
deep within stromatolites to photosynthesise using low-energy infrared
light, the only light able to penetrate into the structure, which
challenges further our understanding of the physical limits of
photosynthesis.
Dr Chen, from the School of Biological Sciences, explains:

"Finding  the new chlorophyll was totally unexpected - it was one of those
serendipitous moments of scientific discovery.
"I was actually looking for chlorophyll d, which we knew could
be found in cyanobacteria living in low light conditions. I thought
that stromatolites would be a good place to look, since the bacteria in
the middle of the structures don't get as much light as those on the
edge."

After obtaining a sample of stromatolite from Hamelin Pool, Dr Chen looked for chlorophyll d
by culturing the cyanobacterial sample in infrared light of 720nm. This
ensured only the survival of cyanobacteria that had chlorophylls able
to absorb and use infrared light.
High performance liquid chromatography of the cultured sample
performed six months later revealed not only trace amounts of
chlorophyll d, but also a new chlorophyll not seen before.

Testing the optical absorption spectrum of the new chlorophyll
revealed that it could absorb much longer wavelengths of light than any
other known chlorophyll - 10nm longer than chlorophyll d and more than 40nm longer than chlorophyll a.
Sequential mass spectral analysis revealed the molecular weight of
the new pigment to be 906 mass units. Then nuclear magnetic resonance
(NMR) spectroscopy was performed to determine the chemical structure of
the chlorophyll. Results indicated that chlorophylls a, b, d and f
have very similar chemical structures, differing only in the position
of a substitution. Yet these tiny differences in structure give the
chlorophylls very different spectral properties, and hence can function
in very different light environments.

"Discovering this new chlorophyll has completely overturned the
traditional notion that photosynthesis needs high energy light," Dr Chen
said.


"It is amazing that this new molecule, with a simple change to its
chemical structure, can absorb extremely low energy light. This means
that photosynthetic organisms can utilise a much larger portion of the
solar spectrum than we previously thought and that the efficiency of
photosynthesis is much greater than we ever imagined.

"Chlorophyll f, and its ability to absorb infrared light, can have numerous applications to industries like plant biotechnology and bioenergy.


"For us, the next challenge is to work out the function of this new chlorophyll in photosynthesis.
"Is its job to capture additional red light and pass it on to another
chlorophyll, like chlorophyll a, in the reaction centre for
photosynthesis?

"Or is it the only chlorophyll responsible for photosynthesis in the
cyanobacterium? And if it is, then we will be speechless wondering how
this molecule can get enough energy from infrared light to make oxygen
from water.


"Whatever happens next, the fact that we have discovered a
cyanobacterium that exploits a tiny modification in its chlorophyll
molecule to photosynthesise in light that we cannot see, opens our mind
to the seemingly limitless ways that organisms adapt to survive in their
environment."