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Engine On a Chip May Beat the Battery
Krishna Dagli writes, "MIT researchers are putting a tiny gas-turbine engine inside a silicon chip about the size of a quarter. The resulting device could run 10 times longer than a battery of the same weight, powering laptops, cell phones, radios, and other electronic devices." From the article: "All the parts work. We're now trying to get them all to work on the same day on the same lab bench." The goal is to do that by the end of the year.
And you thought a hot battery in your lap was scary.
I Am My Own Worst Enemy
Yesterday they were putting lasers on a chip. Today it's engines. Tomorrow, I suppose I'm just going to live on a chip.
Slashdot Burying Stories About Slashdot Media Owned
more reason to increase gas prices
The greatest revenge in life is massive success.
Explode?
I guess instead of building a better battery it's build a better generator. I guess all that matters is the efficiency of the design. My question is obviously heat production, and probably not as important exhast gases. How clean will this device burn. How well will these gases coexist with heat, and ionization.
Sounds like a interesting replacement for motors too.
It's the energy source of the future! It's...
...gas?
Caffeine is my anti-drug!
Duranin - A NWN2 Roleplaying Persistent World
I always thought that what computers were missing was the pull chain for starting the engine. Now it'll be just like using the lawnmower! BBBBRRRRBRBRBRRBBRRRRR!!!!!!!!!!!
The article doesn't mention what happens to the hot exhaust after it passes through the turbine. Does this mean that have not tackled this problem yet? This could give a whole new meaning to the whole "laptop frying your balls".
Miniature fighter jets with lasers all etched out of a silicon crystal.
We could drop half a billion of them over the middle east.
That's a really interesting read (pancake analogy aside), although it sounds like the resulting device will be pretty fragile. A small grain of sand or a little dust buildup would cause complete failure. Large mechanical systems have the ability to power through minor problems like that, but such a small one will not really be suited for military field use, I imagine.
...So now when DHS raises the terror alert, our cell phones will cost more, too?!
That doesn't sound right...
Today they made a miniprojector: http://news.bbc.co.uk/2/hi/technology/5359724.stm
OK, I can picture the gas microturbine, and I can picture how a fuel/combustion energy source can outpower an electochemical energy source. However, do we have the capacity to make a generator that small. After all, we have the rotary power, how do we convert that into electrical energy?
I would be more interested in a bioelectric power source, like electric eel cells fed with sucrose.
When our name is on the back of your car, we're behind you all the way!
Why don't they produce a heatpiped heatsink that's combined with a small type stirling engine where the heat source would be the chip itself.
...a teeny, tiny seagull flies into the turbine?
Then they spend 200% of the allotted time to make sure what they wrote in the first 10% interact with one another correctly.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
Since the mass of these materials is super small, the fact that they are moving at high velocity is no cause to hide under one's bed.
.. assuming that the "revolution" is a distance of 1 or 2 millimeters .. the ACTUAL velocity is nothing to send a letter home with.
.. the total force cannot exceed the energy output of the gas expansion .. which is the result of a few micrograms of fuel.
Also, at 20,000 rpm
Do the math (remember we are talking about the speed of the part of the object that is actually moving).
Another way of looking at it
Given all the issues with "liquids" and flaming laptop batteries, I doubt this will be allowed on aircraft. (We'll see if methanol fuel cells pass TSA muster). I guess that's just another example of the terrorists winning their goal of keeping people out of the 21st century.
Two wrongs don't make a right, but three lefts do.
A microturbine requires a completely new energy source; can you imagine plugging a butane canister into your portable? All turbines have physical issues around energy lost through heat; remember in a traditional engine only about 50% of fuel burned actually goes to perform work.
/\/\icro/\/\uncher
I have to wonder how efficient it will be. Two things drive the efficiency of a gas turbine. The heat differentials and that leakage between the blades or impeller and the housing.
The leakage is going to be a real issue since it is a ratio between the disk size and the gap. Bigger engines mean a higher ratio. That is one of the reasons that BIG gas turbines are relatively efficient while small one suck fuel like there is no tomorrow.
See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
moving parts.
I would say I might be the perfect fuel source for my new laptop and cell phone.
(runs to buy's bean futures...)
I would imagine if it burns a fuel, it spits out carbon.
We need to stop burning stuff for our energy. Sure, batteries store energy made by mostly burning coal and stuff, but there other options for generating electricity to fill those batteries that don't involve adding carbon. I wish these people focused their research towards these types of energy sources.
Remember, we are talking about a replacement for batteries here.
Like a battery, this is not something that is going to be recharged in the field. They will just swap out one micro generator for another and send the used up one off somewhere for refeulling so the dust or sand is not an issue.
Simple, small gas engines in lawnmowers and scooters are far, far dirtier than in a large modern car engine that has extensive polution control systems even when you take into account how much more gas a car uses than a lawnmower.
So I can't imagine this thing will run very clean at all. Not much room to put in a catalytic converter or other cleaning methods.
I have to wonder what a hundred million of these things running will do to indoor air quality. I don't think I want a thousand of these inside my office building.
the total force cannot exceed the energy output
I think you need to check your units there, boyo.
Excellent idea for packing a lot of power into a small space, but there's nothing about where the exhaust goes. How much does it produce? What about hundreds of these little turbines running at the same time in a closed-atmosphere, like a plane? Do we need to hook up little straws to pump the exhaust outside? How about oxygen supply for combustion?
Other than the obvious geek factor, why would we want to increase our dependancy on a fossil fuel.
--
Luck is just skill you didn't know you had.
I'm not sure that's entirely fair; there are lots of systems that don't much like getting dirt in them, but that's what filters are for. Compared to a horse, an internal-combustion engine probably seems like it's really prone to problems -- after all, a horse doesn't mind if there's some dirt in its feed, but put the same amount of dirt into a tank of gas and run it directly into an engine, and you'll probably have issues. Hence, fuel and oil filters.
They're not unsolvable problems. I assume that actual production units of a micro-turbine would have various types of fuel filtering, and apart from the filters, would exist in a hermetically-sealed case.
Think about hard drives: a few specks of dust in there would result in data loss, and it gets worse all the time -- as the data density increases, the amount you could lose due to one dirt particle grows. But properly ruggedized, there's no reason why they can't be used in the field.
Once the initial technology is developed, the encapsulation into a usable consumer (or military) device is QED by comparison; there are a lot of companies who are pretty good at that sort of thing, so I really think it's the least of the problems this would encounter.
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
Makes it look like the first gas turbine car of the 21st century will be a Matchbox car.
"It's the height of ridiculousness to say for those 9 lines you get hundreds of millions."
They will have to reinstitute smoking sections on aircraft.
"Will you be flying in fumes or non-fumes, sir?"
I would just like to mention that the vertical HP ad in this article that blocked the content has caused me to install Adblock Plus and I will now be ignoring all ads on slashdot. You guys lost ad revenue from me because of the annoying ads. Good day.
What the geeks at MIT have done is to create a portable explosive device. If the energy is drawn down in small increments, that device works like a battery. You can run your laptop for an eternity.
However, if the energy is drawn down to 0 joules in 1 millisecond, then the device will blow up the automobile which you are driving.
can you imagine plugging a butane canister into your portable?
Yes.
It makes a whole lot more sense to me than just cursing as the machine shuts down because the battery is depleted, and you're nowhere near a power outlet.
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
thats why we do an envirrrronmental impact analysis.
How many hours will it run before it needs an oil change?
That sounds like what happened with the M-16 machine gun. It's a really nice gun, but it has really tight tollerances, and doesn't operate very well when it's dirty, and hence it requires lots of cleaning, or it tends to jam. The AK-47 on the other hand, operates pretty well even when it is dirty, which is nice in combat situations, since you don't want your gun jamming in the middle of a battle. For more information, check out the wikipedia article
Anthropic principle: We see the universe the way it is because if it were different we would not be here to see it.
How cool will it be when you turn your laptop on and it sounds like a jet engine starting up!
...only much bigger since it will actually be moving significant amounts of air through it. I would imagine changing an intake air filter on one of these things could require use a clean room, but nonetheless, a very fine filter system would be in order. This would mean that efficiency would drop over time as dirt built up at the intake.
So what are the consequences for the environment here? I realise that it's not nice to have billions of batteries lying around, but do these mini-furnaces cause any other kind of pollution? I did not find anything about this in the 'challenges ahead' section, nor do I know much about gas (no pun intended) to be honest.
Try 20,000 revs / sec
E = 1/2 mV^2
Mass should be small since mass/volume hase cubing scaling. I expect MIT is not too concerned about it since they did not mention it.
I used to work at Cummins research center -- watch a turbocharger burst test if you get the chance, basically dump in as much fuel/air as it takes to get the flywheel to fly apart. Test is: is the casing is strong enough to contain all the flying pieces.
...government agency to get involved in another product! I can see it now as a new advertising come on:
Now! New MacBook Pro - EPA approved! Improved catalytic converter design! Larger, more efficient muffler! Meets EPA SPMML standards! (Seconds per micro-milliliter)
"Money is truthful. If a man speaks of his honor, make him pay cash." Notebooks of Lazarus Long, Robert A. Heinlein
Except I don't have a reliable baseline of "causes to hide under one's bed". Curse this overprotective society we live in!
will they be putting tiny engines inside silicon*e* ? Just imagine, breasts that swing *themselves* even when the woman is standing still. It truly would be Utopia. Or Stepford. I always get those two confused.
Can it beat John Henry and his mighty hammer? Didn't think so!
Assault rifle, not machine gun.
My karma makes buddha cry.
What he is saying was that at worse you would would be the same result as exploding a few microgram of fuel. No big deal.
I have been reading /. for quite a few years and have yet to see a single important technological breakthrough mentioned here to make it to the public. Well, with the possible exception of the Segway, which is just hype, not breakthrough.
Fluids in general behave much more differently in microscopic quantities than in large bulk quantities. I expect to be lugging large batteries for some time to come.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
...then I can eat Mexican food for lunch and power my laptop for free!
Insisting on "correct" English is like saying that there is only one, definitive recipe for chili.
Just what we need these days, not less but MORE dependence on fossil fuels. What idiots! Besides the obvious problem of trying to fuel something that small at the gas pump and then paying for it in fractions of a penny, what about the carbon dioxide emissions that conbustion engines produce? Aren't we going to be in for a lot of people with lots of headaches and brain damage from using a device like this? Even though it's so small, it's STILL emitting carbon dioxide which is known to cause the more serious cases of fatal death. I still get behind my roaring battle cry: SOLAR POWER IS WHERE IT'S AT FOLKS!!! The sun is an abundant energy source. Amp the solar panel production up so that they are 99.999% efficient, and you won't need any other source of energy anywhere on the planet. Combine that with electricity resevoirs that can hold a couple hundred gallons of electricity, and you have a clear winner. Thumbs down on this for sure.
-"...bad old ideas look confusingly fresh when they are packaged as technology" - Jaron Lanier (Digital Maoism on Edge.o
Jet turbine article posting!
I know what the AC was attempting to say, but that's not what he ACTUALLY said. Force only correlates with energy if it's applied over a distance or there's a varying potential field. When you say X cannot exceed Y, X and Y need to have the same units, or you're just talking gibberish.
TFA said it runs at 20 krps, which would be 1.2 million rpm. Even if the mass is low, do you really want to be around when the compressor and/or turbine blades come apart? Historically, compressor disintegration has been a Bad Thing.
20 January 2017: the End of an Error.
That is bullshit. You can swap a battery out for another one; in some laptops there are multiple batteries so you can do it without even hibernating the unit first. Users will definitely want to refuel in the field, while the laptop is in use.
It's not an issue anyway. You use a porous single element filter in between the fuel fill and the fuel storage. Problem solved. This amazing technology appears in your butane lighter, too.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
However - no one has mentioned Reynold's Number http://en.wikipedia.org/wiki/Reynolds_number which, regardless of the mass and diameter scaling, will probably be the death of this in efficiency terms. However if there are quantum effects at play (and there may well be at this scale) - then all bets are back on ....
Yeah, when my laptop runs out of butane, I could just plug it into that butane outlet in the wall...
-
That's not entirely true anyway. The real problem (mentioned by the wiki article) is that the M16 was believed to be self-cleaning, and isn't. They didn't issue cleaning kits. If you clean the gun, it remains fairly reliable, and if you configure it properly, it can be more accurate than the AK, anyway. (The AK's first two rounds are pretty good, but it climbs heavily after that.) Of course, M16s are usually set up for tumble, so that the tiny .223 caliber rounds have more of a tendency to hit bones and bounce around, rather than punching a small hole straight through someone.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
Where are you going to find a gas station that small?
What? One sentence you are arguing against me, than your are agreeing. Im confused.
Maybe my use of the word "this" confused you. "This" is the micro-generator-thingie, not the device that is powered by it. Oc COURSE you can swap out a dischardged one. Thats the whole frigging point.
And like todays batterys, refilling/recharging would probably be an option, but depending on the application they may want to do that in the field.
Could a Beowulf cluster of these power a town?
No, guys, we said we wanted you to find a way to replace gasoline engines with batteries, not batteries with gasoline engines. Sheesh.
It's worse when the mass is low. I think of the other end, That tiny piece of pointy metal won't dissapate the energy over much area when it hits something which has a higher penetrating factor. I could be wrong, but I'm thinking of several micro-bullets, hopefully the casing and plastic are strong enough...
That'd be great. Then all I'd have to do is invent what Ali G and Ralph Nader thought of: a way to harness farts!
does it run on regular or unleaded?
Donald Ray Moore Jr. (mindrape)
Suspected Terrorist
eom
Imagine a Beowulf of these...
I could build a car.
"Give orange me give eat orange me eat orange give me eat orange give me you." -Nim Chimpsky
2-stroke lawn mower? I haven't seen one of those in ages. I think LawnBoy made two-stroke mowers for a long time, but I thought they were all 4-stroke nowadays. Now my chainsaw, leaf-blower, hedge-clipper and weed-trimmer, are a different story.
For non-gearheads: If you need to fill 'er up with a mix oil+gasoline, you got yerself a 2-stroke.
The most important thing to do in your life is to not interfere with somebody else's life. -FZ
and irons my trousers when it lets down some steam
Well according to another article the turbine is 4mm in diameter, so google says .5 * 4mm * pi * 20000 is about 125.6 meters. 125 meters per second is about the velocity of a low end bb gun. Given my adolecent expirimentation in terminal ballistics, a similar low end bb gun will barely penetrate both sides of a soda can. It should be a simple matter to provide the engine with a scatter shield stronger than a soda can.
"Prefiero morir de pie que vivir siempre arrodillado!"
Lets see, computer chips that require fuel. Gas is a bit enviro-unfriendly, so, why not alcohol? BENDER IS BORN!
Well, a bottle of plain water (about 1 kg of matter) contains roughly 100 petajoules (10^17 J), and still they are known to explode very infrequently. What matters is how stable the energy state is.
Hollywood has been waiting for this for decades.
Now that's progress.
Barney Fife at the airport security checkpoint will have a field day with this baby.
"No fear. No envy. No meanness." Liam Clancy
I saw a documentary on the development of the Airbus 380... they showed the blade failure test for the engines. Same problem. They ran the engine up to full speed then detached one of the turbine blades. Big noise but the engine housing held all of the debris... amazing.
I don't read your sig. Why are you reading mine?
where are you going to find a tiny mechanic to change the tiny spark plugs and tiny oil filter?
They're using their grammar skills there.
Hate to reply to myself as a general rule, but I thought a little searching would pay off.
Here is a movie from Rolls Royce, not exactly the same, but it's nice.
Does a nice gun cause fun pain, sweet death and happy mutilation ?
The article didn't say anything about how they plan to fuel the little bugger (a small fuel tank about the size of a battery maybe?) or how they're going to handle the exhaust (pretty warm I'd imagine). Quite an achievement though and really makes one wonder where all this miniaturization will eventually lead (micro surgical robots in the bloodstream perhaps? Heheh).
Heard any good sigs lately?
WORD. What you said. Units matter.
Why yes, I AM a rocket scientist!
That is a truely scary idea. Get your hands away from my Lagavulin!
Cheers,
Toby Haynes
Anything I post is strictly my own thoughts and doesn't necessarily have anything to do with the opinions of IBM.
Also, the square-cube law is seriously working in favor of these tiny things. I doubt that they are being stressed to anywhere near the point of disinegration.
"Prefiero morir de pie que vivir siempre arrodillado!"
Hot exhaust? What about poisonous exhaust? There's a reason people don't leave their car engines running in the garage with the door down. Can you imagine 50-100 laptops running these in a college lecture hall?
I realize you were making a joke, but I just thought I'd point out that what I was trying to get at in my original post, is that it's impractical to carry around as much energy stored electrochemically in batteries, as you can store in the form of combustible hydrocarbons.
l (this is for methanol in a fuel cell, its thermal energy density is probably higher)
So if your battery runs out, it's probably not practical for you to just keep shoving new batteries in it for very long, because the energy density just isn't there. You would probably have a tough time carrying the battery equivalent of a few liters of methanol or LPG.
A person could easily carry around enough butane or methanol to keep a computer running for a long time; thus a wall socket is not necessary. And although you jest, although I've never seen a butane socket, natural gas lines are widely available in urban areas (although if you want to store it, you'd need liquefaction apparatus), and ethanol retail outlets aren't hard to find in most areas either. (Actually, in my area, they're already run by the government...)
Just for reference, the energy density of methanol is around 22 MJ/kg [1], while a good LiIon battery is around 150 Wh/kg [2], or around 540 kJ/kg; that's a difference of over 40x. So you could stray a lot further from existing infrastructure with a "portable" device powered by methanol than you could on batteries.
[1] http://hypertextbook.com/facts/2005/JennyHua.shtm
[2] http://en.wikipedia.org/wiki/Lithium-ion_battery
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
"Hey boss, c'mere! I got our engine-on-a-chip to work!"
*boss meanders on over*
*turbine stops spinning*
*boss walks away grumbling*
"Bbbbbut it worked! Really, it did!"
(PS: did anyone notice the "No Karma Bonus" checkbox?)
:(){
Also: what happens if your fuel tank springs a leak? Is that covered under your warranty? For how long? 12 months and one day later the tank leaks and bingo: dead computer.
If they do build this idiotic device, for true masturbatory pleasure, get pr0n running in one window, and a collapsing ecology in the other.
It's all sex and death in mother nature's plans...
HH
The total energy can easily exceed the energy of the gas expansion - you're neglecting the kinetic energy of the turbine blades and whatever they're attached to, which can come from gas burned previously. For large turbines the kinetic energy works out to orders of magnitude more than potential energy of the gas in the turbine. In fact, it's the primary way that momentary dips and spikes in the demand for electricity in the grid are buffered, and a large turbine can store on the order of 10^9 joules of kinetic energy.
I wonder what happens to the power cell when you try to turn your laptop 180 degrees with this thing spinning 20,000 rpm. You're completely reversing the momentum of the turbine, and unlike in a jet engine, it happens rather quickly and rather frequently.
As they are still obviously in development of a benchtop prototype, I further wonder if that thought has crossed their minds.
I'm thinking longevity here, not safety. Precession would create a high load on the shaft and bearings.
One thing no-one has mentioned yet is what will result if it all works. It seems at least plausible that mass produced micro turbines will become a reality, and that the power to weight ratio really will be ten times that of batteries.
SO....when you unplug your laptop from the wall, will you want to immediatly burn expensive butane cartriges? Of course not. Ergo : the hybrid laptop!
There would be a regular lithium ion battery that would last for about an hour in a high end laptop, and then the generator would be started. Also, 10 watts....you might have a battery for surges of power and for when running high power drawing applications such as games. Just like a hybrid using the battery for acceleration.
Is that gas as in gasoline or gas as in something that is a gas at room temperature?
I kind of assumed that using a liquid-at-room-temperature-and-pressure fuel at that scale wouldn't work and that you'd have to use a gas...
If you used hydrogen then your byproduct is water, which is easy enough to get rid of and won't leave any residues. To use bio-diesel would be bordering on stupid in this case, you'd be venting all sorts of chemicals to atmosphere (eg carbon monoxide), and the residues would clog the system up almost instantly at that scale - have you ever seen the inside of an ICE after it has been running for a while on petrol or diesel? I know bio-diesel is a bit cleaner but not that much cleaner...
and if you configure it properly, it can be more accurate than the AK
Which means it operates at tighter tolerances, which means it's more susceptible to dirt.
While the "self cleaning" issue was the lion's share of the problems with the M16 that Vietnam made so famous, the fact does remain that the AK-47 is inherently more reliable than the M16, while being inherently less accurate.
Sort of like a Les Baer competition 1911 vs. a Glock 19.
Reality has a conservative bias: it conserves mass, energy, momentum...
Or like a P-O 1911 vs. a 1911 made in 1911? :)
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
it would also provide much needed exercise for people chained to their keyboards. on the flipside, it would require lance armstrong to maintain a server farm.
Of course, this doesn't mean that I think that research into the concept should stop or anything; materials science continues to improve, and as time goes on maybe somebody will hit on a design concept that will actually work. But I wouldn't expect this kind of thing to start appearing in your laptop computer any time soon.
Any sufficiently advanced technology is indistinguishable from a rigged demo
--Andy Finkel (J. Klass?)
Ooops - can't take the fuel through security...
Might as well stop working on this technology right now...
> For non-gearheads: If you need to fill 'er up with a mix oil+gasoline,
> you got yerself a 2-stroke.
True only for small two-cycle gasoline engines that use the crankcase as a compressor. Large marine and stationary diesels have been mostly two-cycle for about 100 years. These engines have, if anything, lower emissions than equivalent four-cycle engines.
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
I must have pissed off some pussy moderator - ive been getting a lot of bullshit bogus moderation this week.
Well, there's no -1 Asshat moderation, so this is what you get for being one.
And in case you have trouble keeping track, your only "Troll" posts this week are these three.
What's going to be the next great innovation in portable power - world's tiniest steam engine?
sic transit gloria mundi
My inner geek loves the idea, but my inner slacker says it's never gonna happen. (And then my defences say I didn't want it anyway)
-
Right, such an asshat, for you know, wanting someone to actually use terminology correctly. Damn that scientific accuracy, it's just for big jerks.
What a shocker, I've been modded down for bullshit reasons exactly 5 times this week. Shame the number 5 isn't somehow a natural number for moderation or anything.
> I would imagine changing an intake air filter on one of these things could
> require use a clean room...
No.Just a two stage filter.
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
On the other hand this has an angular velocity only 1/10th of a large scale gas turbine and has square-cube law working in it's favor for strength.
"Prefiero morir de pie que vivir siempre arrodillado!"
How much carbon is in your self righteous whining? You seem to have plenty. How about we burn that? Or, hey, how about thinking for half a second that not everything burns fossil fuels!
My old job used to spin shafts weighing several tons up to about half those RPMs to balance them. They had some pretty thick walls on that room.
imagine if you can hack it so the turbine shatters, taking your computer down with it.
Also I don't know how comfortable I am about more moving parts. The more solid state a laptop, the better imho. less shit that can break when you drop it (ask me, i've destroyed 5+ laptop hdds in the last 3 years)
shooting is not too good for my enemies
Excess heat can be converted into electricity via the Pyroelectric effect cover the chips surface with a film of gallium nitride (GaN), caesium nitrate (CsNO3), polyvinyl fluorides, derivatives of phenylpyrazine, and cobalt phthalocyanine and retrieve some of the wasted heat energy.
In the not too distant future, next Sunday A.D.
See prior art.
Wouldn't it be appropriate to call this project, "The Little Engine That Could"? :-)
Diesel injected two strokes engines - when used at the rpm and power level they were designed for - don't waste fuel (they only waste air). On the other side, gasoline two-strokes waste fuel as unburnt exhaust gasses
Let's microfabricate microdeathmicrostar and microrule the whole microworld!
Infact 80-20 split is the lower end of the scale. Most of the time it is skewed even more highly. For executables it is likely to be 95-5 split. I once profiled a complex (as in complex number with real and imaginary parts) matrix solver that spent 90% of the time in complex::operator*() and complex::operator+(). BTW just by correcting the rookie mistake of return result; to return &res; speeded up the code by 20%.
The last 20% of any project takes 80% of the time. Whether it is hardware of software, getting all components to work in isolation qualifies as 20% completion of the total project. BTW, I dont work on web projects with PHP/java/javascript. I work in Computational Electro Magnetics. Mostly C++, non-graphical, non-event driven hard core simulation of physics.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
Outside of some used for testing and research purposes, I can think of no use for them today. Turbofans and turbojets and turboprops account for 99.9999999% of the jets you see today.
And yes, I do have a degree in aerospace.
The maximum risk is limited by the amount of fuel in the battery, not the chamber.
The device has inertia, and can accumulate the energy produced by the fuel in combustion.
I presume that the maximum energy available at any one time is limited by the physics (which does not include the rated revolution - but rather includes the melting speed, or the equilibrium speed - that is the speed at which the losses due to friction and inefficiency equals the energy being input by the fuel.)
The speed is high, but the mass surrounding the turbine relative to the momentum of the turbine, would generally prevent a dangerous projectile; however, should a crack occur first in the shell, followed by a shattering of the turbine, pieces could be expelled at a good velocity - in the end, it appears the temperature of the projectile would be a greater risk than it's speed.
AIK
I wonder if they will be allowed on planes?
TV-MA - the Beginning: "Ward, don't you think you were a little hard on the Beaver last night?"
lick my balls
Now it makes sense, it should be a chip not a battery on his shoulder. "I dare you to knock this chip off my shoulder. I dare you." Man, I'm old.
If a job's not worth doing, it's not worth doing right.
At 1,200,000 RPM I bet this pup makes some noise. Google turned up nothing with load or noise? I bet much of the noise in in the ultrasonic range - might be a bit dangerous?
/. would have their BS filters tuned to this.
I thought more folks at
Accuracy has to do with the design and placement of the sights and their relationship to the bore.
The placement of the sights and their relationship to the bore will, certainly, affect the accuracy of a rifle as fired by a person. But that doesn't mean that tolerances of manufacture don't affect the inherent accuracy of a rifle.
Try this experiment sometime: affix an AK-47 to a rest on a shooting bench, such that it can't move. Fire thirty rounds through it at a target. Measure the spread of the resulting pattern. Do the same with an M16.
I maintain that the spread from the M16 will be smaller than from the AK-47, resulting from the inherent greater accuracy of the rifle. If the results match my expectations (and they have when I've run the experiment), this cannot be due to the sight picture, which is strictly useful to the person aiming the rifle.
Reality has a conservative bias: it conserves mass, energy, momentum...
Ants on stationary bicycles could probably outrun this gas turbine gadget. ;-)
"I hope you like Guinness, Sir. I find it a refreshing substitute for, er... food." Col. Jack O'Neil, SG-1
Excuse me,
However 90% of lawnmower engines are 4 stroke engines. eg: Briggs & Stratton, Techumseh. Lawn Boy is the only manufacturer I know who makes a 2 stroke lawnmower engine. Weedwackers, hedge trimmers, go-peds, dirt bikes, model airplanes, are generally 2 strokers.