Tuesday
January 25, 2005
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University researchers use microfabrication to build more affordable engines for tomorrow's automobiles
By Genevieve Lampinen Daily Science Reporter I aggg SEMgA
The widely publicized hydrogen fuel
cell has capabilities that go beyond
any traditional energy source, with
many hoping that it will end America's
dependency on fossil fuels.
But because of its high cost and fragil-
ity, as of now, the highly efficient electrical
device has yet to be commercialized.
Researchers on campus are currently
solving some of the complex problems that
have prevented the fuel cell - which theo-
retically could be used to supply electricity
to anything from cell phones to cars - from
being available for everyday purposes.
A hydrogen fuel cell works by running
off of the negative electrons of hydrogen to
generate electricity. The electrons from the
hydrogen then recombine with the protons
of oxygen to form liquid water.
With this kind of battery that undergoes
no form of combustion, emissions are very
low, making fuel cells more environmen-
tally sound.
However, aside from the expensive build-
ing materials, one other major obstacle to the
proliferation of fuel cells is the high costs of
their maintenance and manufacturing.
Levi Thompson, a researcher at the Uni-
versity, is working on creating ground-
breaking manufacturing methods that would
allow fuel cells to be assembled without the
high costs.
"If we can optimize the methods we may
use less of those expensive materials," said
Thompson, chemical engineering professor.
While fuel cells are traditionally assem-
bled in individual pieces and then put
together to make one large fuel cell, Thomp-
son is applying microfabrication to create
fuel cells that consist of multiple mini-fuel
cells.
In microfabrication, many tiny structures,
about the size of one micrometer, are put
together in thin layers. For the construction
of fuel cells, Thompson said he can use this
manufacturing technique to add sheet-like
layers of micro-fuel cells to create a fuel
cell.
This manufacturing method could sig-
nificantly decrease the cost of hydrogen fuel
cells from $10,000 a kilowatt to less than
$1,000.
"There could be some limited applica-
tions within the next few years, most of
those will be small devices ... but this is
still research. It's up to the companies to
decide if it's actually commercializable or
not," Thompson said.
Anna Stefanopoulou, an associate mechan-
ical engineering professor also involved in
fuel cell research at the University, thinks
that fuel cells are of more importance glob-
ally than just in America.
In countries without fossil fuel infra-
structures, fuel cells can provide a means
of electricity that they would otherwise be
without, Stefanopoulou said.
"We can actually be global players and
change a lot of things all over, not just in the
U.S.," Stefanopoulou said.
Stefanopoulou is working on improving
the dependability of the fuel cells, another
problem that is also hampering its commer-
cialization.
"I am basically trying to understand what
the fuel cell needs at all times. I think the most
important problem right now is the reliability:
How long can it be used, what kind of cycles can
they be used for before they are pushed into their
limit," Stefanopoulou said.
Currently, Stefanopoulou is using com-
puter-programming techniques to develop
algorithms that will solve intricate problems
involving the dynamics and performance of
fuel cells.
"Chemical engineers put (fuel cells)
together years ago, but you can not yet put
them in a real-world application. If some-
thing goes wrong with them, there are not
very many ways we can predict what went
wrong," Stefanopoulou said.
Last Wednesday, Gov. Jennifer Granholm
joined representatives from several automo-
tive corporations in a discussion panel high-
lighting Michigan's role in commercializing
fuel cell technology.
The University will play a large role in
these technological advancements, said
Automotive Research Center Director Den-
nis Assanis.
"The energy questions that our society
faces are really grand and we have to find
ways to improve conservation resources ...
with the automotive sector being responsi-
ble for one-third of energy consumption in
this country, working on environmentally
friendly alternatives can make a dramatic
difference for years to come," Assanis said.
But these reforms are still a distant vision
for the automobile and other commercial
industries.
As of now, fuel cells are used in very
specific applications,..such as spacecrafts,
where cost is not an issue, said David Cole
of the Automotive Research Center.
In the near future, Cole said fuel cells will
probably be used as power plants.
"The first significant application is not
going to be automotive but a distributive
electrical power generation. Large utilities
will be in the middle of this," Cole said.
Researchers agree that consumers won't
use fuel cells in major applications such as
automobiles for at least 15 to 20 years when
costs will hopefully have decreased.
"The biggest challenge is a straightfor-
ward one ... economics from the stand-'
point of the consumer and we need a lot of1
invention ... when it will occur or if it will
occur is still a question," Cole said.
electrons
Fuel H2
Hydrogen
0 protons
Air Containing 02
(Oxygen)
'
Exhaust
Air +
Water
GRAPHIC BY LINDSEY UNGAR
TOP: A fuel cell In the automotive lab on North Campus.
BOTTOM: The diagram shows the process a fuel cell undergoes to generate electricity.
The negative electrons of the hydrogen fuel first produce electricity and then combine
with the protons from the oxygen In the air which then form liquid water. .
Physics professor
taps into the potential
" of thermoelectrics
The science behind the
pain medication scandal
The improved technology
would boost current
methods of energy transfer
By Scott Siglin
For the Daily
Imagine Navy ships that have the stealth of an
eagle, cars that can fuel themselves electrically
with their own exhaust, computers that run 50
percent faster after being cooled and refrigerators
that run quieter than the night.
These ideas may become realities in the near
future because of thermoelectrics.
"Thermoelectrics has terrific potential for the
future. We are trying to make thermoelectrics a
mainstream part of the electrical industry" for
industries and even household life, said Physics
Prof. Ctirad Uher.
Thermoelectrics, at a fundamental level, is the
conversion of two different forms of energy. The
first thermoelectric devices turned electrical ener-
gy into heat, also known as thermal energy.
A typical thermoelectric device is comprised
of two synthetic semi-conducting metallic bars
which are connected together at the top of each
bar. An electrical current is run through these
conducting bars and the movement of electrons
through these highly specialized conducting
bars creates a temperature gap - where the
top side becomes very hot, while the bottom
side remains cold.
However, thermoelectric devices can also act in
* the opposite direction.
The temperature gap can be made into electri-
cal energy - all that is needed is a hot and cold
surfaces. Uher's research attempts to make the
process of thermoelectrics more efficient.
"The efficiency of a thermoelectric devise
is determined by two factors, the materials
used and clever designing." His research is
primarily focused on what materials the bars
are composed of, and he believes the right
composition of elements will produce higher
efficiencies.
Currently, Uher is testing out several differ-
ent elements that would allow the conversion of
energy to proceed at a higher rate. Today, thermo-
Thermoelectrics are beneficial in more ways
than just converting energy. "Thermoelectrics are
quieter, have increased longevity comparatively
and are healthier for the environment," Uher said.
He explained that thermoelectrics don't use rotat-
ing, moving parts, thus reducing noise and wear
and tear of most motors.
In addition, hazardous fluids, such as radia-
tor fluid that cool the engine of a car, won't be as
needed and will reduce the emission of poisonous
gases into the air.
Thermoelectrics could have a positive indirect
relationship with the environment as well. Many
car manufacturers and even the federal govern-
ment are investing money into thermoelectric
research. The basic idea is to attach these devises
to the tailpipe of a car capturing the heat from the
exhaust.
"(A third) of the exhaust from a car is wasted.
It is just heat released into the air," Uher says.
Currently, Uher and General Motors are work-
ing together to try and figure out a way to capture
this thermal energy and convert it into electri-
cal energy that could potentially power the car's
Uher predicts the
efficiency can be
raised to 15 to 20
percent, which would
yield up to three times
as much energy
many other gadgets.
This in turn could reduce the gas mileage for
many cars since the excess gas that is used now,
won't be needed in the future.
But Uher added that this decrease won't be
drastic.
"I could see a decrease in the amount of gas
used, but it might be slight," he said.
The Navy also wants to install thermoelec-
trics into their ships.
The heat from the boilers and the cold-
ness of the water could potentially generate
By Sunil Patel
For the Daily
Drugs in the news are no surprise, but
recently the drugs making headlines have
been the legal ones.
In the last several months, drugs once
recognized as safe have been linked with
health risks leading to heart attacks and
strokes. Drug manufacturer Merck has
recalled its arthritis and acute pain medi-
cine, Vioxx, Pfizer has issued warnings
for Celebrex and Bextra, also used for
arthritis pain, and most recently, the Food
and Drug Administration issued a cau-
tionary statement for the over-the-counter
painkiller Aleve.
Accompanying the news reports on the
harmful nature of these drugs are the buzz-
words COX-2 inhibition. What they mean and
how pain medications can affect the heart,
however, are often left unexplained.
Mark Fendrick, a doctor of internal
medicine at the University Hospital who
has studied the safety of arthritis medi-
cation, says the issue is prostaglandins.
Found nearly everywhere in the body,
they are the chemicals that produce the
signals that cause pain - most common
pain medications work by inhibiting pros-
taglandin formation.
Aside from inducing pain, prostaglan-
dins also play an important role in the
cardiovascular system. One type, pros-
tacyclin, causes the relaxation of blood
vessels and slows the formation of blood
clots. A relaxed blood vessel is wider, so
unclotted blood cells flow more easily.
Another type, thromboxane, does the very
opposite. Clotted cells can have difficul-
ty flowing through a vessel narrowed by
thromboxane.
"They make the blood vessels smooth or
sticky," Fendrick said.
The major enzyme responsible for the for-
mation of these molecules is cyclooxygenase,
or COX. It creates the starting molecule from
which the prostaglandins are formed.
For years, scientists believed it was a single
enzyme, but recent research suggests they
were wrong.
In 1989, researchers at Washington Uni-
versity stumbled upon a possible new COX
"I find it ironic that a drug that was developed
to enhance safety may meet its demise due to
safety concerns."
- Mark Fendrick
University doctor of internal medicine
fraternal twin.
This new form, called COX-2, was thought to
be inducible, meaning it would lie dormant until
inflammation turned it on. If COX-1 was like a
student during finals, tirelessly working day and
night, then COX-2 was like procrastinating stu-
dent during the semester, doing nothing until a
deadline spurred him into action.
Since traditional painkillers that target
both forms of COX were found to cause
adverse side effects, such as bleeding in the
stomach and intestines, scientists looked
for alternative options. They thought they
had found one in COX-2.
COURTESY OF MERCK
"What makes COX-2 inhibitors 'cool,' "
Fendrick said, "is not that they block COX-2
but that they don't block COX-1."
Scientists thought not blocking COX-1 was
safer, as COX-1 helped protect the lining of
the stomach and intestines. Blocking only
COX-2 seemed logical because it was turned
on only in inflamed tissue, causing pain. Sci-
entists believed that unlike COX-1, it had no
function in healthy tissue. They were wrong
about that, too.
the Journal of Immunology reported strong evi-
dence that COX-1 seems to favor the production
of thromboxane, which encourages blood clot-
ting, whereas COX-2 seems to favor the produc-
tion of prostacyclin. The balance of power comes
into play again, and each enzyme plays a role in
maintaining its own side.
For most nonsteroidal anti-inflammatory
drugs, or NSAIDs, like aspirin, ibuprofen
or naproxen - the generic name for Aleve
- this is not a problem. NSAIDs are non-
selective, meaning they block the action of
both COX-I and COX-2. At recommended
doses, they have a stronger effect on COX-
1. At higher doses, however, increased
COX-2 inhibition becomes an issue, which
prompted the recent statement about high
doses and long-term use of Aleve.
However, COX-2 inhibition is the only
factor when it comes to COX-2 inhibitors
like Vioxx, Celebrex and Bextra. While
selective COX-2 inhibition alleviates pain,
it also ends up reducing the body's normal
supply of prostacyclin, which helps pre-
vent blood clots. It removes an important
protective mechanism, leaving patients
already at risk for heart problems more
vulnerable.
Fendrick thinks this explanation is a
"leap of faith," though, as evidence for
it has not been found in the autopsies of
patients. But he added that COX-2 inhibi-
tors are no better at relieving pain than
the NSAIDs - that they have never been
proven to be more effective: "This is a
myth that needs to be broken."
The Canadian pharmaceutical company
Dimethaid is trying to take advantage of
recent events by increasing the marketing
for its topical cream Pennsaid, which is
already being distributed in some Europe-
an countries. Pennsaid is an NSAID like
aspirin, but because it is a cream and not a