Afterburners in your pocket (the winged PDA is over the corner)

http://www.cdrinfo.com/Sections/News...x?NewsId=11169

Miniature jet engines could power cellphones

Engineers have moved a step closer to batch producing miniaturised, jet
engine-based generators from a single stack of bonded silicon wafers.

These chip-based ?microengines? could one day power mobile electronic
devices.

By spinning a tiny magnet above a mesh of interleaved coils etched into
a wafer, David Arnold and Mark Allen of the Georgia Institute of
Technology, US, have built the first silicon-compatible device capable
of converting mechanical energy - produced by a rotating microturbine -
into usable amounts of electrical energy.

The key advantage of microengines is that they pack in at least 10 times
more energy per volume of fuel than conventional lithium batteries, take
up less space and work more smoothly than much-touted fuel cells.

Jet engines are remarkable pieces of equipment in terms of efficiency,
explains Stuart Jacobson at the Massachusetts Institute of Technology,
US, who collaborates with Arnold and Allen.

For the first time we have got macro-sized amounts of energy from a
micro-scale device,? says Arnold. This is a crucial if micro-engines are
to find their way into actual products, Allen adds.

Off-the-shelf components
Until now, two separate teams, led by Jacobson and Carlos
Fernandez-Pello at the University of California in Berkeley, US, have
focused on how to convert the chemical energy stored in the diesel fuel
into the mechanical energy that drives the turbine - the first part of
the microengine process.

Both have already etched prototype silicon combustion chambers capable
of burning diesel at very high temperatures without cracking, and
miniature silicon turbines, using batch-scale manufacture techniques.
But they captured the electrical energy produced using off-the-shelf
components that were not part of the same stack of silicon wafers.

Now, for the first time, Arnold and Allen have demonstrated that the
generation of electricity from the spinning turbine can actually be done
on a silicon-compatible wafer.

They spin a flat metal ring - about the diameter of a penny - made up of
alternating 45° sections of magnetic north and south poles. For the sake
of the experiment, the micro-turbine was replaced by an air-powered
drill like those used by dentists.

As the magnet spins, its rapidly switching magnetic field induces a
current in metal coils deposited on an etched ferromagnetic layer
underneath. It produces 1.1 watts of power. This is already enough to
power a cellphone or GPS receiver, says Arnold, and it is just in the
research stage.

Brittle magnets
Achieving this power requires 100,000 revolutions per minute, extremely
fast compared to car engines, which spin at just 3000 rpm. Magnets are
brittle and tend to be pulled apart by the centrifugal force at high
speeds, so Arnold and Allen optimised the thickness and width of the
magnetic ring before encasing it in a layer of strengthening titanium.

They also had to work out the best dimensions for the three interleaving
coils that sit below the spinning magnet and produce the current. They
decided on an array about 100 microns tall, reducing electrical
resistance as much as possible to ensure that the maximum current is
squeezed out of each magnet rotation.

While the magnetic generator is an ?exciting step?, the next hurdle is
integrating the manufacture of the turbine, combustor and electricity
generator into a single stack of bonded silicon wafers, says Mike Waits,
an electrical engineer at the Army Research Lab in Adelphi, Maryland,
which is funding the research.

The US Army expects that soldiers - who currently rely on
battery-powered laptops, night-vision goggles and GPS systems - will be
the first to use the microengines. "The army has a tremendous power
problem - soldiers get bogged down by their batteries,? explains
Jacobson.

Devices that run on diesel would be a boon for the army because it is
widely available as tank fuel anyway, adds Waits.

Arnold and Allen will present their advance at the International
Conference on Micro Electro Mechanical Systems (MEMS) in January 2005.

From NewScientist.com

What's awesome is that I go to Georgia Tech and I'm an Aerospace Engineering
major!


"Tamas Feher" wrote in message
...
http://www.cdrinfo.com/Sections/News...x?NewsId=11169

Miniature jet engines could power cellphones

Engineers have moved a step closer to batch producing miniaturised, jet
engine-based generators from a single stack of bonded silicon wafers.

These chip-based ?microengines? could one day power mobile electronic
devices.

By spinning a tiny magnet above a mesh of interleaved coils etched into
a wafer, David Arnold and Mark Allen of the Georgia Institute of
Technology, US, have built the first silicon-compatible device capable
of converting mechanical energy - produced by a rotating microturbine -
into usable amounts of electrical energy.

The key advantage of microengines is that they pack in at least 10 times
more energy per volume of fuel than conventional lithium batteries, take
up less space and work more smoothly than much-touted fuel cells.

Jet engines are remarkable pieces of equipment in terms of efficiency,
explains Stuart Jacobson at the Massachusetts Institute of Technology,
US, who collaborates with Arnold and Allen.

For the first time we have got macro-sized amounts of energy from a
micro-scale device,? says Arnold. This is a crucial if micro-engines are
to find their way into actual products, Allen adds.

Off-the-shelf components
Until now, two separate teams, led by Jacobson and Carlos
Fernandez-Pello at the University of California in Berkeley, US, have
focused on how to convert the chemical energy stored in the diesel fuel
into the mechanical energy that drives the turbine - the first part of
the microengine process.

Both have already etched prototype silicon combustion chambers capable
of burning diesel at very high temperatures without cracking, and
miniature silicon turbines, using batch-scale manufacture techniques.
But they captured the electrical energy produced using off-the-shelf
components that were not part of the same stack of silicon wafers.

Now, for the first time, Arnold and Allen have demonstrated that the
generation of electricity from the spinning turbine can actually be done
on a silicon-compatible wafer.

They spin a flat metal ring - about the diameter of a penny - made up of
alternating 45° sections of magnetic north and south poles. For the sake
of the experiment, the micro-turbine was replaced by an air-powered
drill like those used by dentists.

As the magnet spins, its rapidly switching magnetic field induces a
current in metal coils deposited on an etched ferromagnetic layer
underneath. It produces 1.1 watts of power. This is already enough to
power a cellphone or GPS receiver, says Arnold, and it is just in the
research stage.

Brittle magnets
Achieving this power requires 100,000 revolutions per minute, extremely
fast compared to car engines, which spin at just 3000 rpm. Magnets are
brittle and tend to be pulled apart by the centrifugal force at high
speeds, so Arnold and Allen optimised the thickness and width of the
magnetic ring before encasing it in a layer of strengthening titanium.

They also had to work out the best dimensions for the three interleaving
coils that sit below the spinning magnet and produce the current. They
decided on an array about 100 microns tall, reducing electrical
resistance as much as possible to ensure that the maximum current is
squeezed out of each magnet rotation.

While the magnetic generator is an ?exciting step?, the next hurdle is
integrating the manufacture of the turbine, combustor and electricity
generator into a single stack of bonded silicon wafers, says Mike Waits,
an electrical engineer at the Army Research Lab in Adelphi, Maryland,
which is funding the research.

The US Army expects that soldiers - who currently rely on
battery-powered laptops, night-vision goggles and GPS systems - will be
the first to use the microengines. "The army has a tremendous power
problem - soldiers get bogged down by their batteries,? explains
Jacobson.

Devices that run on diesel would be a boon for the army because it is
widely available as tank fuel anyway, adds Waits.

Arnold and Allen will present their advance at the International
Conference on Micro Electro Mechanical Systems (MEMS) in January 2005.

From NewScientist.com

In article ,
"JaKoB" jakob.jc@gmail...... wrote:

What's awesome is that I go to Georgia Tech and I'm an Aerospace Engineering
major!



Just wait until the first guy puts one of these in his pocket while it
is running!



"Tamas Feher" wrote in message
...
http://www.cdrinfo.com/Sections/News...x?NewsId=11169

Miniature jet engines could power cellphones

Engineers have moved a step closer to batch producing miniaturised, jet
engine-based generators from a single stack of bonded silicon wafers.

These chip-based ?microengines? could one day power mobile electronic
devices.

By spinning a tiny magnet above a mesh of interleaved coils etched into
a wafer, David Arnold and Mark Allen of the Georgia Institute of
Technology, US, have built the first silicon-compatible device capable
of converting mechanical energy - produced by a rotating microturbine -
into usable amounts of electrical energy.

The key advantage of microengines is that they pack in at least 10 times
more energy per volume of fuel than conventional lithium batteries, take
up less space and work more smoothly than much-touted fuel cells.

Jet engines are remarkable pieces of equipment in terms of efficiency,
explains Stuart Jacobson at the Massachusetts Institute of Technology,
US, who collaborates with Arnold and Allen.

For the first time we have got macro-sized amounts of energy from a
micro-scale device,? says Arnold. This is a crucial if micro-engines are
to find their way into actual products, Allen adds.

Off-the-shelf components
Until now, two separate teams, led by Jacobson and Carlos
Fernandez-Pello at the University of California in Berkeley, US, have
focused on how to convert the chemical energy stored in the diesel fuel
into the mechanical energy that drives the turbine - the first part of
the microengine process.

Both have already etched prototype silicon combustion chambers capable
of burning diesel at very high temperatures without cracking, and
miniature silicon turbines, using batch-scale manufacture techniques.
But they captured the electrical energy produced using off-the-shelf
components that were not part of the same stack of silicon wafers.

Now, for the first time, Arnold and Allen have demonstrated that the
generation of electricity from the spinning turbine can actually be done
on a silicon-compatible wafer.

They spin a flat metal ring - about the diameter of a penny - made up of
alternating 45° sections of magnetic north and south poles. For the sake
of the experiment, the micro-turbine was replaced by an air-powered
drill like those used by dentists.

As the magnet spins, its rapidly switching magnetic field induces a
current in metal coils deposited on an etched ferromagnetic layer
underneath. It produces 1.1 watts of power. This is already enough to
power a cellphone or GPS receiver, says Arnold, and it is just in the
research stage.

Brittle magnets
Achieving this power requires 100,000 revolutions per minute, extremely
fast compared to car engines, which spin at just 3000 rpm. Magnets are
brittle and tend to be pulled apart by the centrifugal force at high
speeds, so Arnold and Allen optimised the thickness and width of the
magnetic ring before encasing it in a layer of strengthening titanium.

They also had to work out the best dimensions for the three interleaving
coils that sit below the spinning magnet and produce the current. They
decided on an array about 100 microns tall, reducing electrical
resistance as much as possible to ensure that the maximum current is
squeezed out of each magnet rotation.

While the magnetic generator is an ?exciting step?, the next hurdle is
integrating the manufacture of the turbine, combustor and electricity
generator into a single stack of bonded silicon wafers, says Mike Waits,
an electrical engineer at the Army Research Lab in Adelphi, Maryland,
which is funding the research.

The US Army expects that soldiers - who currently rely on
battery-powered laptops, night-vision goggles and GPS systems - will be
the first to use the microengines. "The army has a tremendous power
problem - soldiers get bogged down by their batteries,? explains
Jacobson.

Devices that run on diesel would be a boon for the army because it is
widely available as tank fuel anyway, adds Waits.

Arnold and Allen will present their advance at the International
Conference on Micro Electro Mechanical Systems (MEMS) in January 2005.

From NewScientist.com

"Orval Fairbairn" wrote in message
news | In article ,
| "JaKoB" jakob.jc@gmail...... wrote:
|
| What's awesome is that I go to Georgia Tech and I'm an Aerospace
Engineering
| major!
|
|
|
| Just wait until the first guy puts one of these in his pocket while it
| is running!
|
|



I'll be waiting for the model with drop tanks - for those long meetings.



Pocket-to-pocket refuelling would be too fruity.


--

Cheers


Dave Kearton

"Dave Kearton" wrote in
message ...
"Orval Fairbairn" wrote in message
news | In article ,
| "JaKoB" jakob.jc@gmail...... wrote:
|
| What's awesome is that I go to Georgia Tech and I'm an Aerospace
Engineering
| major!
|
|
|
| Just wait until the first guy puts one of these in his pocket while it
| is running!
|
|



I'll be waiting for the model with drop tanks - for those long meetings.



Pocket-to-pocket refuelling would be too fruity.

Not if the two users are male and female

--

Cheers


Dave Kearton

In article , "David E. Powell"
wrote:

"Dave Kearton" wrote in
message ...
"Orval Fairbairn" wrote in message
news | In article ,
| "JaKoB" jakob.jc@gmail...... wrote:
|
| What's awesome is that I go to Georgia Tech and I'm an Aerospace
Engineering
| major!
|
|
|
| Just wait until the first guy puts one of these in his pocket while it
| is running!
|
|



I'll be waiting for the model with drop tanks - for those long meetings.



Pocket-to-pocket refuelling would be too fruity.

Not if the two users are male and female

Lends new meaning to probe and drogue

--
Harry Andreas
Engineering raconteur