Hydrogen released to fuel cell more quickly when stored in metal nanoparticles

ScienceDaily (Oct. 1, 2011) — Researchers from TU Delft and VU University Amsterdam in the Netherlands have demonstrated that the size of a metal alloy nanoparticle influences the speed with which hydrogen gas is released when stored in a metal hydride. The smaller the size of the nanoparticle, the greater the speed at which the hydrogen gas makes its way to the fuel cell.

The researchers publish their findings in the October issue of the scientific journal Advanced Energy Materials.

Hydrogen heaven

On 27 September Dutch Minister of Infrastructure and the Environment, Ms Schultz van Haegen, announced she will earmark 5 million Euros to stimulate hydrogen transport in the Netherlands. According to the Minister the Netherlands and neighbouring countries have all it takes to become a 'hydrogen heaven'. In July 2011, the German car manufacturer Daimler announced its intention to build twenty new hydrogen fuelling stations along Germany's motorways. Hydrogen is back on the agenda. Hydrogen gas is currently stored in a vehicle fuel tank at 700 bar pressure. Fuelling stations thus require high-pressure pumps to fill these tanks and these systems consume a lot of energy.

Hydrogen storage

There are thus good reasons for finding alternative hydrogen storage techniques. Hydrogen can be absorbed in high densities in metals such as magnesium, without the need for high pressure. However, the disadvantage is that releasing the hydrogen again is a very difficult and very slow process. One way of speeding up the release of the hydrogen is to use magnesium nanoparticles that are fixed in a matrix to prevent them from aggregating.

Nanoparticles in a matrix

Professor of Materials for Energy Conversion and Storage, Bernard Dam, and his colleagues at TU Delft and VU University Amsterdam have demonstrated experimentally that the interaction between the nanoparticles and the matrix can cause the hydrogen gas to be released faster. Using models consisting of thin layers of magnesium and titanium, they show how the pressure of the hydrogen being released from the magnesium increases as the layers become thinner. This means that it indeed makes sense to store hydrogen in nanoparticles in a matrix. The choice of matrix determines to what extent the hydrogen desorption pressure increases. The researchers published their findings in the October 2011 edition of the scientific journal Advanced Energy Materials.

Efficient and affordable hydrogen storage techniques can play an important role in the large-scale adoption of hydrogen fuel cells. Bernard Dam foresees the development of hybrid vehicles that use batteries for short distances but switch to hydrogen for long distances: 'Your electric motor will be powered by batteries inside the city, and by hydrogen when you go further afield.'

The research was funded by the ACTS Sustainable Hydrogen Program of the Netherlands Organisation for Scientific Research.

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Delft University of Technology.

Journal Reference:

Lennard P.A. Mooij, Andrea Baldi, Christiaan Boelsma, Kun Shen, Marnix Wagemaker, Yevheniy Pivak, Herman Schreuders, Ronald Griessen, Bernard Dam. Interface Energy Controlled Thermodynamics of Nanoscale Metal Hydrides. Advanced Energy Materials, Volume 1, issue 5, pages 754-758, October 2011.

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Hydrogen released to fuel cell more quickly when stored in metal nanoparticles

ScienceDaily (Oct. 1, 2011) — Researchers from TU Delft and VU University Amsterdam in the Netherlands have demonstrated that the size of a metal alloy nanoparticle influences the speed with which hydrogen gas is released when stored in a metal hydride. The smaller the size of the nanoparticle, the greater the speed at which the hydrogen gas makes its way to the fuel cell.

The researchers publish their findings in the October issue of the scientific journal Advanced Energy Materials.

Hydrogen heaven

On 27 September Dutch Minister of Infrastructure and the Environment, Ms Schultz van Haegen, announced she will earmark 5 million Euros to stimulate hydrogen transport in the Netherlands. According to the Minister the Netherlands and neighbouring countries have all it takes to become a 'hydrogen heaven'. In July 2011, the German car manufacturer Daimler announced its intention to build twenty new hydrogen fuelling stations along Germany's motorways. Hydrogen is back on the agenda. Hydrogen gas is currently stored in a vehicle fuel tank at 700 bar pressure. Fuelling stations thus require high-pressure pumps to fill these tanks and these systems consume a lot of energy.

Hydrogen storage

There are thus good reasons for finding alternative hydrogen storage techniques. Hydrogen can be absorbed in high densities in metals such as magnesium, without the need for high pressure. However, the disadvantage is that releasing the hydrogen again is a very difficult and very slow process. One way of speeding up the release of the hydrogen is to use magnesium nanoparticles that are fixed in a matrix to prevent them from aggregating.

Nanoparticles in a matrix

Professor of Materials for Energy Conversion and Storage, Bernard Dam, and his colleagues at TU Delft and VU University Amsterdam have demonstrated experimentally that the interaction between the nanoparticles and the matrix can cause the hydrogen gas to be released faster. Using models consisting of thin layers of magnesium and titanium, they show how the pressure of the hydrogen being released from the magnesium increases as the layers become thinner. This means that it indeed makes sense to store hydrogen in nanoparticles in a matrix. The choice of matrix determines to what extent the hydrogen desorption pressure increases. The researchers published their findings in the October 2011 edition of the scientific journal Advanced Energy Materials.

Efficient and affordable hydrogen storage techniques can play an important role in the large-scale adoption of hydrogen fuel cells. Bernard Dam foresees the development of hybrid vehicles that use batteries for short distances but switch to hydrogen for long distances: 'Your electric motor will be powered by batteries inside the city, and by hydrogen when you go further afield.'

The research was funded by the ACTS Sustainable Hydrogen Program of the Netherlands Organisation for Scientific Research.

Recommend this story on Facebook, Twitter,
and Google +1:

Other bookmarking and sharing tools:

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Delft University of Technology.

Journal Reference:

Lennard P.A. Mooij, Andrea Baldi, Christiaan Boelsma, Kun Shen, Marnix Wagemaker, Yevheniy Pivak, Herman Schreuders, Ronald Griessen, Bernard Dam. Interface Energy Controlled Thermodynamics of Nanoscale Metal Hydrides. Advanced Energy Materials, Volume 1, issue 5, pages 754-758, October 2011.

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Model finds optimal fiber optic network connections 10,000 times more quickly

ScienceDaily (June 28, 2011) — Designing fiber optic networks involves finding the most efficient way to connect phones and computers that are in different places -- a costly and time-consuming process. Now researchers from North Carolina State University have developed a model that can find optimal connections 10,000 times more quickly, using less computing power to solve the problem.

"Problems that used to take days to solve can now be solved in just a few seconds," says Dr. George Rouskas, computer science professor at NC State and author of a paper describing the new method. The model could solve problems more than 10,000 times faster when data is routed through larger "rings," in the network, Rouskas says.

Every time you make a phone call or visit a website, you send and receive data in the form of wavelengths of light through a network of fiber optic cables. These data are often routed through rings that ensure the information gets where it needs to go. These ring networks are faced with the constant challenge of ensuring that their system design can meet user requirements efficiently. As a result, ring network designers try to determine the best fiber optic cable route for transmitting user data between two points, as well as which wavelength of light to use. Most commercial fiber optics handle approximately 100 different wavelengths of light.

Solving these design challenges is difficult and time-consuming. Using existing techniques, finding the optimal solution for a ring can take days, even for smaller rings. And a ring's connections are modified on an ongoing basis, to respond to changing use patterns and constantly increasing traffic demands.

But the new model developed by Rouskas and his team should speed things up considerably. Specifically, the researchers have designed a mathematical model that identifies the exact optimal routes and wavelengths for ring network designers. The model creates a large graph of all the paths in a ring, and where those paths overlap. The model then breaks that graph into smaller units, with each unit consisting of the paths in a ring that do not overlap. Because these paths do not overlap, they can use the same wavelengths of light. Paths that overlap cannot use the same wavelengths of light -- because two things cannot occupy the same space at the same time.

By breaking all of the potential paths down into these smaller groups, the model is able to identify the optimal path and wavelength between two points much more efficiently than previous techniques.

"This will significantly shorten the cycle of feedback and re-design for existing rings," Rouskas says. "It also means that the ring design work can be done using fewer computer resources, which makes it less expensive. This should allow network providers to be more responsive to user demands than ever before."

The paper, "Fast Exact ILP Decompositions for Ring RWA," is published in the July issue of the Journal of Optical Communications and Networking. The paper was co-authored by Dr. Emre Yetginer, a former postdoctoral researcher at NC State now at Tubitak UEKAE, and NC State Ph.D. student Zeyu Liu.

NC State's Department of Computer Science is part of the university's College of Engineering.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by North Carolina State University.

Journal Reference:

Emre Yetginer, Zeyu Liu, George N. Rouskas. Fast Exact ILP Decompositions for Ring RWA. Journal of Optical Communications and Networking, 2011; 3 (7): 577 DOI: 10.1364/JOCN.3.000577

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

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Animals quickly colonized freshwater

EARLY WORMSquiggles in this 530-million-year-old Californian rock come from the wormlike animal Arenicolites — the earliest evidence for creatures living in freshwater environments, scientists say.Martin Kennedy and Mary Droser/Geology 2011

Earth’s early animals moved upstream not long after conquering the seas, newly discovered fossils show.

Rocks near the California-Nevada border preserve traces of tiny worms that squiggled through river mud some 530 million years ago. That’s roughly 80 million years earlier than other freshwater animal fossils, paleontologists report online May 4 in Geology, and not long after the first appearance of diverse animal forms in marine environments.

Changing levels of saltiness can make it tough to evolve from living in the ocean to living in rivers and lakes, says Mary Droser, a paleontologist at the University of California, Riverside. The new work shows that “clearly animals had crossed that physiological barrier very early on,” says Droser, who made the find with Martin Kennedy of the University of Adelaide in Australia.

The scientists stumbled across the fossils in eastern California’s Wood Canyon Formation, parts of which were deposited under a salty sea and other parts under a river. In the freshwater layers the paleontologists spotted lots of squiggly marks — traces of U-shaped burrows in which two wormlike species once lived.

Animals must have worked their way from the sea through brackish water and into freshwater by the time the rocks formed, Droser says. If so, freshwater environments were a fairly hospitable place to live early in animal history — a time well before plants colonized land about 450 million years ago, which some scientists think was a crucial stage in stabilizing river landscapes enough for animals to thrive there.

“The knee-jerk thing, since most of the world is covered by ocean, is to say that most fossils are marine, and the onus is to prove that they’re not,” Droser says. “This will open people’s eyes up.”

Other paleontologists, she says, might now start finding earlier and earlier evidence for this key freshwater step in animal history.

But not all scientists are convinced by the new report. Knowing which rocks were truly deposited in a river, as opposed to the ocean or along the coast, is difficult, says paleoecologist Molly Miller of Vanderbilt University in Nashville. A study published earlier this year in Sedimentology, for instance, argues that the Wood Canyon rocks may have lain quite close to the coast and thus been flooded with both freshwater and saltwater. "The fact that these are sandwiched between rocks deposited in marine environments raises the bar of evidence required," Miller says.
Found in: Earth and Life

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Self-powered, blood-activated sensor detects pancreatitis quickly and cheaply

ScienceDaily (Apr. 25, 2011) — A new low cost test for acute pancreatitis that gets results much faster than existing tests has been developed by scientists at The University of Texas at Austin.

The sensor, which could be produced for as little as a dollar, is built with a 12-cent LED light, aluminum foil, gelatin, milk protein and a few other cheap, easily obtainable materials.

The sensor could help prevent damage from acute pancreatitis, which is a sudden inflammation of the pancreas that can lead to severe stomach pain, nausea, fever, shock and in some cases, death.

"We've turned Reynold's Wrap, JELL-O and milk into a way to look for organ failure," says Brian Zaccheo, a graduate student in the lab of Richard Crooks, professor of chemistry and biochemistry.

The sensor, which is about the size of a matchbox, relies on a simple two-step process to diagnose the disease.

In step one, a bit of blood extract is dropped onto a layer of gelatin and milk protein. If there are high levels of trypsin, an enzyme that is overabundant in the blood of patients with acute pancreatitis, the trypsin will break down the gelatin in much the same way it breaks down proteins in the stomach.

In step two, a drop of sodium hydroxide (lye) is added. If the trypsin levels were high enough to break down that first barrier, the sodium hydroxide can trickle down to the second barrier, a strip of Reynold's wrap, and go to work dissolving it.

The foil corrodes, and with both barriers now permeable, a circuit is able to form between a magnesium anode and an iron salt at the cathode. Enough current is generated to light up a red LED. If the LED lights up within an hour, acute pancreatitis is diagnosed.

"In essence, the device is a battery having a trypsin-selective switch that closes the circuit between the anode and cathode," write Zaccheo and Crooks in a paper recently published in Analytical Chemistry.

Zaccheo and Crooks, who have a provisional patent, can envision a number of potential uses for the sensor. It might help providers in the developing world who don't have the resources to do the more complex tests for pancreatitis. It could be of use in situations where batteries are in short supply, such as after a natural disaster or in remote locations. And because of the speed of the sensor, it could be an excellent first-line measure even in well-stocked hospitals.

For Zaccheo, the most appealing aspect of the project isn't so much the specific sensor. It is the idea we might be able to save time, money and even lives by adopting this kind of low-tech approach.

"I want to develop biosensors that are easy to use but give a high level of sensitivity," he says. "All you need for this, for instance, is to know how to use a dropper and a timer."

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Texas at Austin.

Journal Reference:

Brian A. Zaccheo, Richard M. Crooks. Self-Powered Sensor for Naked-Eye Detection of Serum Trypsin. Analytical Chemistry, 2011; 83 (4): 1185 DOI: 10.1021/ac103115z

Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Self-powered, blood-activated sensor detects pancreatitis quickly and cheaply

ScienceDaily (Apr. 25, 2011) — A new low cost test for acute pancreatitis that gets results much faster than existing tests has been developed by scientists at The University of Texas at Austin.

The sensor, which could be produced for as little as a dollar, is built with a 12-cent LED light, aluminum foil, gelatin, milk protein and a few other cheap, easily obtainable materials.

The sensor could help prevent damage from acute pancreatitis, which is a sudden inflammation of the pancreas that can lead to severe stomach pain, nausea, fever, shock and in some cases, death.

"We've turned Reynold's Wrap, JELL-O and milk into a way to look for organ failure," says Brian Zaccheo, a graduate student in the lab of Richard Crooks, professor of chemistry and biochemistry.

The sensor, which is about the size of a matchbox, relies on a simple two-step process to diagnose the disease.

In step one, a bit of blood extract is dropped onto a layer of gelatin and milk protein. If there are high levels of trypsin, an enzyme that is overabundant in the blood of patients with acute pancreatitis, the trypsin will break down the gelatin in much the same way it breaks down proteins in the stomach.

In step two, a drop of sodium hydroxide (lye) is added. If the trypsin levels were high enough to break down that first barrier, the sodium hydroxide can trickle down to the second barrier, a strip of Reynold's wrap, and go to work dissolving it.

The foil corrodes, and with both barriers now permeable, a circuit is able to form between a magnesium anode and an iron salt at the cathode. Enough current is generated to light up a red LED. If the LED lights up within an hour, acute pancreatitis is diagnosed.

"In essence, the device is a battery having a trypsin-selective switch that closes the circuit between the anode and cathode," write Zaccheo and Crooks in a paper recently published in Analytical Chemistry.

Zaccheo and Crooks, who have a provisional patent, can envision a number of potential uses for the sensor. It might help providers in the developing world who don't have the resources to do the more complex tests for pancreatitis. It could be of use in situations where batteries are in short supply, such as after a natural disaster or in remote locations. And because of the speed of the sensor, it could be an excellent first-line measure even in well-stocked hospitals.

For Zaccheo, the most appealing aspect of the project isn't so much the specific sensor. It is the idea we might be able to save time, money and even lives by adopting this kind of low-tech approach.

"I want to develop biosensors that are easy to use but give a high level of sensitivity," he says. "All you need for this, for instance, is to know how to use a dropper and a timer."

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Texas at Austin.

Journal Reference:

Brian A. Zaccheo, Richard M. Crooks. Self-Powered Sensor for Naked-Eye Detection of Serum Trypsin. Analytical Chemistry, 2011; 83 (4): 1185 DOI: 10.1021/ac103115z

Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

View the original article here