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Catalyst simulations for fuel cells may make clean cars a reality

September 19, 2009 By admin Leave a Comment

Washington, Sep 18 (ANI): University of Wisconsin-Madison researchers are working towards developing better catalyst for fuel cells in a bid to make clean cars a reality.

If successful, the researchers could make a car that runs on hydrogen from solar power, and produces water instead of carbon emissions.

Materials science and engineering assistant professor Dane Morgan and Ph.D. student Edward (Ted) Holby have developed a computational model that could optimise an important component of fuel cells, making it possible for the technology to have a more widespread use.

The researchers investigated how particle size is related to the overall stability of a material, and showed with their model that increasing the particle size of a fuel cell catalyst decreases degradation and therefore increases the useful lifetime of a fuel cell.

Fuel cells are electrochemical devices that facilitate a reaction between hydrogen and oxygen, producing electrical power and forming water.

In the type of fuel cells Morgan is researching, called proton exchange membrane fuel cells (PEMFCs), hydrogen is split into a proton and electron at one side of the fuel cell (the anode).

The proton moves through the device while the electron is forced to travel in an external circuit, where it can perform useful work, while at the other side of the fuel cell (the cathode), the protons, electrons and oxygen combine to form water, which is the only waste product.

One of the many hurdles to producing efficient fuel cells for widespread use is the catalyst added to aid the reaction between protons, electrons and oxygen at the cathode.

Current fuel cells use platinum and platinum alloys as a catalyst. While platinum can withstand the corrosive fuel cell environment, it is expensive and not very abundant.

Thus, to maximize platinum use, researchers use catalysts made with platinum particles as small as two nanometers, which are approximately 10 atoms across.

These tiny structures have a large surface area on which the fuel cell reaction occurs.

However, platinum catalysts this small degrade very quickly, which means that the fuel cell doesn’t last long.

The researchers have found a possible solution to the rapid degradation problem-when it comes to catalyst particle size, sometimes smaller isn’t better.

In their modelling work, they showed that if the particle size of a platinum catalyst is increased to four or five nanometers, which is approximately 20 atoms across, the level of degradation significantly decreases.

This means the catalyst and the fuel cell as a whole can continue to function for much longer than if the particle size was only two or three nanometers.

“Fuel cells are just one of many energy technologies – solar, battery, etc. – with enormous potential to reduce our dependence on oil and our carbon emissions. Computer simulation offers a powerful tool to understand and develop new materials at the heart of these energy technologies,” said Morgan. (ANI)

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Computational model to examine Alzheimer’s pathways in young adults created

April 19, 2009 By admin Leave a Comment

Washington, Apr 19 (ANI): Scientists at University of Virginia have developed a computational model to examine the role of certain proteins in the development of Familial Alzheimer’s disease (FAD), which affects people as young as 30.

Biomedical engineers Lydia S. Glaw and Thomas C. Skalak, Ph.D., of the Department of Biomedical Engineering, University of Virginia, Charlottesville, constructed the model to measure plaques and tangles and their influence in causing FAD.

The model tested the hypothesis that certain variables-genetic mutations in proteins and “tau” tangles-might be predicative of the development of the disease.

The model is a first-of-its-kind approach to modelling, understanding and predicting Alzheimer’s pathways.

One of the biggest hypotheses tested by the model was the idea that GSK3 is a link between amyloid beta buildup and tau tangle development.

The researchers studied the proteins presenilin-1 (PS1) (a mutated gene found in familial AD) and glycogen synthase kinase (GSK-3) and amyloid beta (Aá) plaque, to quantitatively examine their roles in the development of Alzheimer’s pathology.

The elements were applied to the model, which was constructed of kinetic equations developed from literature searches, and analysed the interactions of the proteins and complexes under various scenarios.

The researchers found that GSK3 had a large effect on tangle formation, but very little on the plaques.

Also, activating GSK3 was not found to be sufficient to cause changes in the brain to the extent seen in Alzheimer’s patients.

However, overproduction of GSK3 as opposed to activation could lead to those changes.

Besides there was no link found between amyloid beta plaque and tau tangles.

They concluded that no single change to the system could cause Alzheimer’s disease; instead it was caused by multiple changes, such as a PS1 mutation combined with GSK3 over-activation.

They suggested that a multi-pronged approach to treating the disease may be best.

The findings will be presented at the 122nd Annual Meeting of the American Physiological Society. (ANI)

Filed Under: Science News Tagged With: biomedical engineering, biomedical engineers, computational model, Engineering University, fad, familial alzheimer, Genetic Mutations, gsk, Hypotheses, kinetic equations, literature searches, overproduction, plaques, pronged approach, proteins, tangle, tau tangles, thomas c, university of virginia, virginia charlottesville, young adults

Social bacteria periodically reverse direction to spread

January 21, 2009 By Rajesh Leave a Comment

London, January 21 (ANI): A collaborative study has revealed that groups of highly social bacteria maintain order by periodically reversing direction.

Microbiologist Dale Kaiser of Stanford University in California and Mark Alber at the University of Notre Dame in Indiana say that groups of myxobacteria change direction at regular intervals in search of food, heading back in the direction of the bacterial colony from which they came before returning to their original course.

They highlighted the fact that scientists had for long been puzzled by the very movement, and wondered why the bacteria would waste energy retracing their steps.

They claimed that their team had developed a model showing that without such periodic reversals, swarms of Myxococcus xanthus would become disordered and move at a slower rate, eventually coming to a standstill.

The researchers said that their findings might be helpful in studying traffic flow, in teaching robots to move in groups, or inventing new biological engines.

“Reversing seems like a silly thing to do. It seems like it would get them nowhere. But, in fact, it gets them everywhere,” Nature magazine quoted Kaiser as saying.

The computational model made by the researchers takes into account the behaviour and cell biology of M. xanthus, and it shows that swarms expand at the greatest rate when cells reverse direction roughly every eight minutes, matching the timing observed in the organism.

The researchers said that, over time, the reversals generate a more orderly swarm, with more cells in parallel, making them less likely to bump into one another.

When the researchers allowed the cells in the model to move, but not to reverse direction, they jammed together and became unable to swarm.

Published in the Proceedings of the National Academy of Sciences, the findings suggest that reversing direction gives the bacteria information about their neighbours’ locations, and allows the group to maintain formation, even in the absence of information about the swarm as a whole.

Meanwhile, although the group loses some distance each time it turns back, its movement in that direction is impeded as more cells are shed from the colony, and ultimately there is still a net movement outwards.

“Individual cells use a lot of energy for reversals, but still it’s beneficial for the whole population,” says Alber. (ANI)

Filed Under: Science News Tagged With: bacteria information, cell biology, change direction, collaborative study, computational model, dale kaiser, mark alber, National Academy of Sciences, nature magazine, neighbours, proceedings of the national academy, proceedings of the national academy of sciences, reversals, silly thing, standstill, stanford university, swarms, traffic flow, university of notre dame, xanthus

Catalyst simulations for fuel cells may make clean cars a reality

Computational model to examine Alzheimer’s pathways in young adults created

Social bacteria periodically reverse direction to spread

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