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More on Micro Turbines 81

Posted by michael from the it-keeps-going-and-going-and-going dept.
goku writes "Nice article here on the development of micro mechanical turbines." We had an older story about mini-turbines as well.
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More on Micro Turbines More

More on Micro Turbines

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  • "The next big thing is really small"

    The nanotech hype is so overblown, when will it finally reach applicable levels?

    Tonight on fox, nanomicroscope made from hydrocarbon chain discovers the penis of John Ashcroft...
    • The nanotech hype is so overblown,

      These are silicon based micromachines. That has little to do with nanotechnology.

  • ooh... pretty (Score:1, Troll)

    by AntiTuX ( 202333 )
    man, I wish I could get ahold of hardware like that sometimes... That's just cooler than shit.
  • this is exactly what I need to power my MicroMachines!
  • I'd just love some small nickel nuclear batteries for my palm organiser. Wouldn't need to make many milliwatts to keep an organiser going. (And a half life of 100+ years!).

    Probably less damaging to the environment than 100 years of batteries, too.

    Michael
    • Wouldn't the lead shielding make your Palm Organiser a little heavy? Also the turbines and the water pipes to convert the nuclear power into electricity make it a little impractical don't you think?

  • They suggest making nuclear "batteries" to fuel - among other things - microscopic planes, and suggest using some radioactive isotope with a half-life (the physics thing, not the game :-) of 102 years. Heck, they apparently already built a power-source of this kind...

    Just don't ask me to power my PDA with this stuff...

    • Why not? They're talking about using them to power aircraft the size of dust particles; people will inevitably inhale these things -- and they'll be just fine. We are surrounded by radioactive sources that emit alpha, beta, and gamma radiation, but they are at low enough levels that the energy does either no damage, or might actually be beneficial to us.

      Given the assumption that a PDA powered by a collection of these things would put out less radiation than a brick (yes, they're radioactive, kids!), why would you have any problem relying on a power source that wouldn't have to be replaced until your children retire?
      • Because the word "nuclear" is as terrifying as the word "witch" was in 17th century Salem Mass.

        And just as reasonably so.

      • Well, I *don't* want to inhale any more radioactive dust than I already do, thank you. Its one thing to have my surroundings contain sources of background radiation (I know about that), but I want to limit the amount that goes *inside* me. The reason is rather simple - the stuff inside me is likely to cause much more damage than the stuff outside me, since sensitive organs would get direct exposure to and particles otherwise absorbed by the skin.


        [snip]why would you have any problem relying on a power source that wouldn't have to be replaced until your children retire?


        This is not the problem - such a power source would be *so* useful. The problem is what the consequences are. Right now, nuclear power is handled reasonably well, since it's the realm of (mostly) highly trained professionals. Once Joe Sixpack starts handling nuclear equipment, *no one* knows what he'll do to it. And please don't tell me that it's his own problem, because *I* will be affected by him not handling it correctly.


  • DARPA (Score:4, Funny)

    by stoolpigeon ( 454276 ) <bittercode@gmail> on Saturday May 18, 2002 @01:37AM (#3541735) Homepage Journal
    One of the most enthusiastic supporters of microengines is the Defence Advanced Research Projects Agency (DARPA) in Washington, DC.

    I would think the short question to ask would be - "What doesn't DARPA fund?" They really should be FARPA - Fund Any Research Project Agency.

    I'm not complaining - just observing

    • Re:DARPA (Score:2, Interesting)

      by caca_phony ( 465655 )
      I would think the short question to ask would be - "What doesn't DARPA fund?" They really should be FARPA - Fund Any Research Project Agency.
      I'm not complaining - just observing

      At the University of Illinois, there was a project called the Biological Computing Laboratory, founded by Cyberneticist Heinz Von Foerster, which did research in second - order cybernetics. (a field devoted to those studies of information, communication, and control in which the observer of the system is an active part of that system, for example analyzing a conversation one is engaged in, or the political system one lives within, in terms of systems theory and information theory). I learned alot from older friends/mentors who were participants in this laboratory, which was shut down, in part, because of the passage of a law (I forget it's year or name), specifying that all defense money go to militarily usable research. The participants of the BCL unanimously refused to change their path of studies to be more directly applicable to military use, and the project lost all funding.

      Apropos the article, it seems inevitable that technologies become smaller and smaller in their implementation, to some limit which we surely have not reached. One could have a mechanical Babbage difference engine style computer in a chip. One could have an analog chemical computer in a chip, even. Commonly used higher-order calculations could be replaced by parametricized measurements of an internal mechanical simulation. I don't know if any of these are of any practical use, but they intregue me.

    • Here in the U.K. it was called DERA (Defence Evaluation and Research Agency) but then split up into Qinetiq plc (at least I think they've floated now although I'm not sure) and the Defence Science and Technology Laboratory. I preferred DERA because they had all the patents they had in a electronic library on their website!
  • Gas turbines are great powerplants, and you'd think that small ones would be everywhere. But decades after big turbines took over as powerplants for large aircraft, little ones are still rare.

    Capstone [microturbine.com] keeps announcing prototypes and demonstration projects, but after years of this, they're still not shipping in volume. Capstone calls their project a "microturbine", but it's a 20KW unit the size of a mini-van.

    • Oh no they're not! ;)

      At least, not at the 'working and manufactured' level. What you need to be Googling for is [b]model aircraft turbines[/b], and that will get you both the sub-35-pound-thrust engines rated for model airplanes, and the larger ones for UAVs.

      I was looking for this just the other day, and found the SWB Turbines [swbturbines.com] site- it's so poorly made that I had to view source to check out the actual engine pages, but they've got from 11 pounds thrust to 107, at sizes and weights from 16" by 6.5" and 11 pounds (that's the 107 pound thrust one) down to this big! [swbturbines.com] (no, NOT goatse...) There's also a picture of a 'Cri-Cri' microlight airplane powered by two SWB-100s instead of little piston engines. This is just one of the companies building tiny turbines- James Engineering Turbines builds a 30 lb thrust one (6.2 lbs weight) called the Cobra, and for actual generators you'd be googling for units like the Garrett GTP30... and for a big engine you'd be thinking in terms of an Allison 250-C18, at 317 HP at 6000 rpm of the output shaft. That's roughly a replacement for a V-8 engine, and smaller than a minivan- L 41" W 21" H 24", and 158 lbs.

      How do I know? 'cos I spent hours yesterday redesigning airplane ideas in the sim 'X-Plane' and plugging in the new values to specify SWB-100 engines.

      Slashdot: home of GEEKS! :D

  • ...carbon monoxide poisoning.

    Before this, air quality problems at work has been addressed by outlawing smoking and mexican food.

  • This is great ... (Score:2, Informative)

    by Rolo Tomasi ( 538414 )
    But in contrast to the technologies mentioned in the article, small, direct-methanol fuel cells (e.g. for powering your notebook) are already being produced [smartfuelcell.de].

    Finally, we're on our way to getting rid of this century-old technology of chemical batteries.

  • Does anyone know anything about thermal gradients pushing this sort of MEM engine?

    I always thought it would be really cool to have trillions of MEMS powered by naturally occurring thermal gradients at the microscopic level. Ya know, all that background ambient heat fluctuation none of us feel could really be harnessed by something small enough.

    • I always thought it would be really cool to have trillions of MEMS powered by naturally occurring thermal gradients at the microscopic level.

      I get the feeling Maxwell's Demon might get jealous and throw a spanner into this idea. At the very least, Demon would unionize the engines and the efficiency would go up in smoke.

  • Screw powering a laptop, I'm gonna take a couple million of these and sew them into my persian rug and fly around like aladdin.

  • Heat? (Score:2, Insightful)

    by mmarlett ( 520340 )
    The article mentioned noise, emissions and vibration as reasons it might not be popular in cell phones and such, but it didn't say anything about heat. Sure, at a 50% efficiency over the 20-30% efficiency of large turbines they would produce less waste heat (proportionately), but would our little friends get hot?

  • It ain't going to happen soon. (Score:5, Insightful)

    by enkidu ( 13673 ) on Saturday May 18, 2002 @03:28AM (#3541903) Homepage Journal
    I usually expect better reporting from the Economist. This is the kind of breathless "This is great! Here's what all the believers have to say!", I expect from "People" or "Popular Mechanics". Here are some of the problems I see with this wonder battery/generator.
    • Operating life. Now, I'm no scientist, but I do know that silicon and high temperatures don't get along too well. But, you could side step that by using similar manufacturing technologies with other materials. Not that I can think of any candidates...
    • A turbine does not a generator make. Show me the electricity! Silicon ain't magnetic people. OK, magnetless generators exist, how about "coils" then? Show me the coils! Until I see a working, efficient, microsized generator, I don't see any of this happening.
    • Call me a crotchety old man, but I just don't buy the efficiency numbers I'm seeing. As things get smaller and smaller, your perceived viscosity goes up and up. Same design + smaller size = less fluidic efficiency. Same goes for the friction + mass problem. Combustion efficiency will probably go up since it's easier to model with the small size.
    This leads me to my problems with the nano-technologists we have nowadays. Where's the power? Anybody have a 1 cubic milimeter battery that'll last 1 hour yet? Show me a self powered nanobot. Hell, show me a nano-power source that works! Remember, volume decreases by the cube as you scale down. Sure a quintillion nano-bots could make me breakfast out of yesterday's trash, but what's going to power them? You can't get out more than you put in, you know. Reminds me of the great Larry Niven's quote: "Another beautiful theory, murdered by a gang of ugly facts."

    I don't see this stuff (nano-technology, micro-turbines) panning out any time soon (Now, bio+nano or plain bio, I can see scaling down. Also, mini-turbines (1-10 cubic centimeters) I can see happening also.

    EnkiduEOT

    • Come on. Chip inductors are hardly a rocket science. You can buy 0402 sized inductors off-the-shelf. They might not be as ubiquitous as resistors, but not exotic either. I think the size designation refers to thousanth of a furlough. It's so small you need microscope, fine tweezers, steady hands and lots of patience to work with those suckers.

    • Re:It ain't going to happen soon. (Score:1, Interesting)

      by Anonymous Coward
      I don't know about the thermal properties of Silicon myself, but many people are working on such generators, using micromachining of silicon, and I'm sure they know what they are doing.

      Your second point is meaningless. There are more ways than just magnetic induction to generate electricity, some of which have been sucesfully used in MEMS for generating power already. Didn't you search the academic literature before posting?

      Your third point is, however, very valid. All these things scale very badly to micro scale.
    • Just gotta say this one thing:

      Bumblebees by macrophysical limitations should not physically be able to fly!

      Things work differently at the (physical)level these people are working at. Give them at least a little credit for spending the time to research and analyze. Surely they would not be publicizing this info without a minimum of verifiable evidence.

      All of your 'evidence' is based on macrophysics and common knowledge. Microphysics and especially that which deals with physics at the molecular level is much different and obeys radically different laws.

      For example, viscosity: rarely does viscosity play any and I mean any role at a microscopic level... otherwise nothing would work... can you imagine molecules behaving according to 'viscosity' instead of various types of polarization or attraction to other molecules... I think not.

      Viscosity is definitely a macroscopic topic and plays absolutely no part in MEMs research... now valence levels and atomic/molecular attraction may be relevant.

      • For example, viscosity: rarely does viscosity play any and I mean any role at a microscopic level

        Actually that's not true. At a microscopic scale (although not at the molecular scale you mentioned), viscosity plays a critical role. What's counter-intuitive is that at these scales, the mass of the fluid is also important. For example, some bacteria swim by spinning a corkscrew-shaped tail. Because the fluid is viscous, the spinning tail exerts a force on the fluid (otherwise it would slip through unimpeded). That force acts on the mass of the fluid, which exerts an equal and opposite force on the bacterium, pushing it forward. Ignore either the viscosity or the mass, and the bacterium can't move.

        Viscosity is typically the primary source of damping for MEMS devices, and is ultimately one of the limiting factors for the microturbine as well. Increasing the size of the gap between the moving and stationary parts can reduce the viscous drag significantly, but also makes the induction less efficient. The good news is that air is a lot less viscous than water, so it's possible to make the device pretty efficient.
    • Who is pioneering controllable ADP? It's the most significant energy producing process in the living organism and I've seen nothing. What gives?


    • I'm no scientist, but I do know that silicon and high temperatures don't get along too well.

      The problem is with mostly doped silicon; at high temperatures the dopants tend to migrate, which is bad for very small, very fast electronics. It isn't a mechanical problem.

      This leads me to my problems with the nano-technologists we have nowadays. Where's the power? Anybody have a 1 cubic milimeter battery that'll last 1 hour yet? Show me a self powered nanobot. Hell, show me a nano-power source that works!

      Sure, if you show me a car that drills its own oil and refines its own fuel from it. Where'd you get the "self powered" requirement? All they need to do for most applications is receive power (e.g. from high frequency sound waves) and convert it to mechanical energy. For the sound waves--which look like pressure waves at that scale--all you need is a piston.

      Remember, volume decreases by the cube as you scale down.

      False logic. The power requierments also scale down, sometimes by as much as the fifth power IIRC.

      Sure a quintillion nano-bots could make me breakfast out of yesterday's trash, but what's going to power them?

      How about yesterday's trash? 1) it's there, and 2) there's plenty of it, so 3) you aren't going to use all of it, and 4) part of what you don't use would burn, so 5) controlled, small scale oxydation (e.g., what microbes, fungi, etc. would do if they were converting the trash) should give you all the energy you need.

      Heck, if you're building a diamondoid structure of some sort instead of just cooking breakfast for a skeptic, you'e have way more reduced hydrogen than you need, so just use that and dump the resulting water.

      -- MarkusQ

      • The problem is with mostly doped silicon; at high temperatures the dopants tend to migrate, which is bad for very small, very fast electronics. It isn't a mechanical problem.
        That's when you're talking about temperatures at the 200 Celcius range. We're talking 2000 Celcius here. Heck, it's a mechanical problem with steel and ceramics. And amorphorous atomic silicon way less durable than steel, titanium and ceramics. And who says that parts of your micro-turbine won't be doped? What about the circuitry?
        All they need to do for most applications is receive power (e.g. from high frequency sound waves) and convert it to mechanical energy. For the sound waves--which look like pressure waves at that scale--all you need is a piston.
        And how will the electronics that control those machines be powered? Oh, with little microscopic sound generators eh? Oh, and that'll be real efficient, heh. Whose going to be making those sound waves? And what about inter nanabot communication?
        How about yesterday's trash? 1) it's there, and 2) there's plenty of it, so 3) you aren't going to use all of it, and 4) part of what you don't use would burn, so 5) controlled, small scale oxydation (e.g., what microbes, fungi, etc. would do if they were converting the trash) should give you all the energy you need.
        Now you're mixing bio-bots and nano-bots which I specifically said at the end was a possibility. Controlled nano (nm) scale oxidation is fine in theory, but we don't even have controlled efficient micro (micro-m) scale oxidation of non-uniform fuel. Heck, we don't even have it on the mini scale (cm).

        Technologies usually take off when most of the basic building blocks are there but it's only missing a piece or two. Then someone develops those pieces and presto, you've got Aibo's running around the house. In the case of nano-bots, we're missing more than half the basic building blocks and they don't look like they're going to appear anytime soon.


        • I had pretty much decided that you were a troll, but looking at your posts on other topics leads me to suspect that you are either just clueless on this one or in a foul mood today.

          In case you are a troll I won't waste too much time rebutting here, but just touch on a few highlights:

          200C is a much better estimate of the temp. than 2000C, which you seem to have just pulled out of your hat as a straw man.
          The "biobot"/nanobot distinction is also a straw man, or at perhaps handwaving flummery.
          Fuel cells already perform controlled micro-combustion on homogenious fuels. Clever filtering can handle mixed fuels.
          Sound waves can be made easily and cheaply with things called "speakers".
          You don't need electronics to control machines.
          The whole point of this is that they are working on new technologies, so saying that they don't exist yet doesn't add information.

          And so forth.

          -- MarkusQ -- MarkusQ

          • I admit that I was in a foul mood caused by uncritical reporting and bullshit research (you should hear my rant on fusion research), but I don't think I'm completely clueless about this.
            200C is a much better estimate of the temp.
            Uhmm, Just doing a quick google search on turbine combustion temperature gives me a figure of 1250F. Or about 675C. I admit that 2000C was a load of horse-pucky but so is 200C. Turbine blades are notoriously difficult to manufacture because of the high stresses and high temperatures involved in their operation. Making them really small doesn't sidestep the issue. Especially with regard to friction.
            * The "biobot"/nanobot distinction is also a straw man, or at perhaps handwaving flummery.
            I disagree. bio-bots (or modified biological organisms) use existing biological power sources whereas pure nano-bots need to start from scratch for their power (micro-turbines etc.) without cribbing the Kreb cycle from mitochondria.
            Fuel cells already perform controlled micro-combustion on homogenious fuels. Clever filtering can handle mixed fuels.
            Fuel cells may be a good option. Hadn't thought of that. Still, filtering isn't going to transform compost into methane (of course, bacteria can do that, but not terribly quickly).
            Sound waves can be made easily and cheaply with things called "speakers".
            Uhmm, to be high in frequency enough to be absorbed/used by nanobots, your average tweeter ain't going to cut it. Let's consider the case of sound waves powering microbots (1mm in size, never mind nanobots (1m in size). Now velocity / wavelength = frequency. 340 m/s / 0.1 mm = 340000mm/s / 0.1 mm = 3400000 Hz or about a sound frequency of 3.4 MHz. For nanobots you'd be talking 3.4 GHz. I don't have much knowledge about sound waves at that frequency other than my intuition that they probably aren't easy to deal with. Of course, I could be completely wrong about that and sound waves may be a viable alternative. Just haven't seen any examples yet. Like I said: Show me the power.
            You don't need electronics to control machines.
            Fluidics then? Pure mechanical linkages? What's the point of a turbine if you're not going to generate electricity? Sure it's probably possible, but how practical are fluidics and/or mechanical gears and cams for complex control?
            The whole point of this is that they are working on new technologies, so saying that they don't exist yet doesn't add information.
            This is true. What I was pointing out was that there were difficulties in the objectives, not posed by techniques not yet invented, but by fundamental properties of scale, materials and physics. In another post I give the example of rotary engines (specifically Wankel type engines). They have better power/weight ratios, fewer moving parts, can handle a wider range of fuels etc. They had one difficulty: the darn seals. This being mostly a problem of geometry and materials. Today, there's only one production car with a rotary engine and I recall that its engine life is pretty stinky compared to well designed piston engines. All because of the seals.

            Yes, it would be cool if nano-bots could make me breakfast everyday. It would be cooler if I could swallow a pill of nano-bots to keep me free of disease and stave off aging. But I just don't see it happening any time soon. No power == no nanobots in my view. Biobots on the other hand, allow us to crib off of a couple billion years of evolution. Why reinvent mitochondria?

            EnkiduEOT


            • Just doing a quick google search on turbine combustion temperature gives me a figure of 1250F. Or about 675C. I admit that 2000C was a load of horse-pucky but so is 200C.

              Remember, if you double the linear scale you have eight times the volume to cool across only four times the surface area. So the smaller you go (other things being equal) the easier cooling will become. More to the point, what really matters isn't the absolute temperature but the gradient. At smaller scales, you can get temperature gradients much higher than you can with larger scales (e.g. in collapsing bubbles) without exposing your components to nearly as high average absolute temperatures.

              Turbine blades are notoriously difficult to manufacture because of the high stresses and high temperatures involved in their operation. Making them really small doesn't sidestep the issue.

              It sure helps. The main problem is finding something that will spin as fast as you like without flying apart. The forces/cross sectional area scale as RPM x r, so for something half the size you can use a material only half as strong.

              Uhmm, to be high in frequency enough to be absorbed/used by nanobots, your average tweeter ain't going to cut it.

              We aren't talking light here; you can extract energy from a pressure wave with a wavelength much larger than you are. You can even build something that sits on a desk to extract power (not much of course) from daily variations in barometric pressure. In effect, it's just a piston.

              You don't need electronics to control machines. Fluidics then? Pure mechanical linkages?

              Sure. Not fluidics of course. See Nanosystems [barnesandnoble.com], Chapter 12, for a proof of concept design using only mechanical linkages.

              Biobots on the other hand, allow us to crib off of a couple billion years of evolution. Why reinvent mitochondria?

              For the same reason we don't harness birds to pull our airplanes. Those billions of years of evolution were hampered by the fact that the beasties had to stay alive every single day. That means no radical redesign, no optimizing for a specific purpose at the cost of evolutionary fitness, etc. As a consequence, we can do many orders of magnitude better than evolution has--when "better" is defined by meeting our needs and not by reproductive success.

              Making them really small doesn't sidestep the issue. Especially with regard to friction.

              Exactly backwards. Friction is a bulk effect; if you make things small enough, the whole concept of "friction" goes away. Of course, we're talking nanoscale now, not microscale, and thus many orders of magnitude smaller than these turbines.

              -- MarkusQ

              • Remember, if you double the linear scale you have eight times the volume to cool across only four times the surface area. So the smaller you go (other things being equal) the easier cooling will become. More to the point, what really matters isn't the absolute temperature but the gradient. At smaller scales, you can get temperature gradients much higher than you can with larger scales (e.g. in collapsing bubbles) without exposing your components to nearly as high average absolute temperatures.
                Good point. However, too much cooling and you lose efficiency. You don't want your combustion chamber to be cool, you want it to be as hot as possible. Yes, you can get higher temperature gradients when you are very very small, but with higher temperature gradients, more rapid cooling and heating, you get other material related problems. Now with clever design, you could probably turn some of those problems to advantages. The power problem, in my opinion, still remains.
                It sure helps. The main problem is finding something that will spin as fast as you like without flying apart. The forces/cross sectional area scale as RPM x r, so for something half the size you can use a material only half as strong.
                Ah, but you also get less power. That's why they need to scale up in RPM. This negates some (if not all) of the advantages gained by scale. You do get better control over defects with smaller scale because there is alot less volume for defects to creep in, so fabrication may be easier.
                We aren't talking light here; you can extract energy from a pressure wave with a wavelength much larger than you are. You can even build something that sits on a desk to extract power (not much of course) from daily variations in barometric pressure. In effect, it's just a piston.
                Ah, but only if you're stationary relative to the pressure wave. Nano-bots are going to be hard pressed to do that with the mass that they have. If the pressure wave is big enough to move you (which I assume to be the case with nano-bots), you're just a particle in the matrix which gets moved around. You'd have to use an intertial generation system, and with masses so small, you'd be hard pressed to extract any usable energy. Show me a realistic design that could work and I'll change my mind. Just a design with the appropriate mass calculations, materials and expected power. It doesn't have to be exact or even workable, but should outline the general principles of how it would work.
                Sure. Not fluidics of course. See Nanosystems [barnesandnoble.com], Chapter 12, for a proof of concept design using only mechanical linkages.
                Mechanical linkages then. No objection with regard to feasability, but with regard to practicality.
                For the same reason we don't harness birds to pull our airplanes. Those billions of years of evolution were hampered by the fact that the beasties had to stay alive every single day. That means no radical redesign, no optimizing for a specific purpose at the cost of evolutionary fitness, etc. As a consequence, we can do many orders of magnitude better than evolution has--when "better" is defined by meeting our needs and not by reproductive success.
                Ah, but what we are trying to accomplish on the nanoscale is quite akin to the aims of what biology has been doing for a billion years or so. Biology hasn't built F-16's because there wasn't any evolutionary gain in building them (there not being any SAM-7's or Su-27's to compete against). But our nano/micro world has been teaming with (competing) life doing all sorts of interesting things (coral, ant colonies, bee hives, bacteria, yeast, fungi just to name a few examples) with close analogues to our aims in nano-technology. On the micro/nano scale of doing things efficiently, we haven't even made it to the stone age when compared to the biological world. Heck, we don't even have fire yet.
                Exactly backwards. Friction is a bulk effect; if you make things small enough, the whole concept of "friction" goes away. Of course, we're talking nanoscale now, not microscale, and thus many orders of magnitude smaller than these turbines.
                I thought friction was a counteracting force to motion, usually at the surface/boundaries. Does friction just magically cease to exist for nanoscale materials? Mechanical linkages don't encounter the problems of viscosity and surface friction? Again, my intuition could be wrong, but it seems to me that the primary problem that ants and small insects deal with in mechanically manipulating their environment is friction. As things scale down, I only expect things to get worse.

                I'm not against people trying to do nanoscale projects as long as they're realistic about their prospects. I have a problem with people trying to do nanoscale stuff before we've even figured out how to do autonomous mini/microscale stuff. I have a problem with supposedly intelligent people not sitting down and doing basic mechanical/physical feasibility checks before zooming off into lala land (often with my tax dollars).

                Like that biology professor and compsci professor a year or so ago, who wanted to make nanobots to monitor and track water pollution, without understanding 1) that radio waves don't work for shit in water, 2) GPS can't work without an appropriately sized antenna, 3) We don't have any designs for your power source, 4) We don't have any communications protocols/designs for 4 billion nanobots scattered in the Monterey Bay and on and on. Now if they had talked about softball/volleyball sized monitors floating or floating and sinking on some random/autonomous pattern, I would have been all for them. But because nano is the cool word of the decade, they spouted on and on about their new research on nanobots. I recall that they got about 1 Megabuck in tax dollars for their research proposal.

                Mostly, I object to more of my tax dollars going to research into nano dreck (and fusion crap) instead of going to research towards more efficient power generation/solar generation/geothermal generation/waste heat utilization/home generation/efficient transportation/waste reduction/erosion prevention; all of which have a darn good chance of improving the state of the world during the next decade.

                WRT to nano + fusion: the next "20 to 30 years" my ass. If we have an actual power generating hot fusion reactor (that is: we start it up and net power comes out) or a useful and efficient nano-bot matrix in less than 25 years (Before 1/1/2028), I'll eat my hat. Heck I'll eat all my hats.

                EnkiduEOT


                • MQR:
                  ...you can extract energy from a pressure wave with a wavelength much larger than you are. You can even build something that sits on a desk to extract power (not much of course) from daily variations in barometric pressure. In effect, it's just a piston.

                  Enkidu:

                  Ah, but only if you're stationary relative to the pressure wave. Nano-bots are going to be hard pressed to do that with the mass that they have. If the pressure wave is big enough to move you (which I assume to be the case with nano-bots), you're just a particle in the matrix which gets moved around. You'd have to use an intertial generation system, and with masses so small, you'd be hard pressed to extract any usable energy. Show me a realistic design that could work and I'll change my mind. Just a design with the appropriate mass calculations, materials and expected power. It doesn't have to be exact or even workable, but should outline the general principles of how it would work.

                  No, you don't have to be fixed in position. It's a lot easier than you seem to be thinking.

                  1. Take a rigid box with one side free to slide in and out (i.e., a piston).
                  2. Inside the box is a gizmo with two arms: one attatched to the piston-wall and the other attached to the opposite wall.
                  3. The box is floating freely in some medium that undergoes periodic pressure changes around a mean value P.
                  4. Inside the box is a fluid of pressure P, or there is a spring attached to the gizmo to give an eqiv. force.
                  5. The gizmo stores power when its arms are "pumped" in and out. It could wind up a spring, do something piezoelectric, whatever.
                  So what happens? As the pressure waves come & go, the piston is pushed in and out, and it extracts power from its environment.
                  I thought friction was a counteracting force to motion, usually at the surface/boundaries. Does friction just magically cease to exist for nanoscale materials? Mechanical linkages don't encounter the problems of viscosity and surface friction? Again, my intuition could be wrong, but it seems to me that the primary problem that ants and small insects deal with in mechanically manipulating their environment is friction. As things scale down, I only expect things to get worse.
                  Your intuition is wrong. Friction is a macroscopic effect, like colour or policical affiliation. Bellow a certain size, it doesn't apply, because the things you are dealing with don't have enough internal complexity to support it. With macroscale objects, there are many, many atoms that meet at the interface, and the sum of all their interactions is what we call friction. At the other extreme, when two atoms meet there are (obviously) only two atoms meeting. To a first aproximation, they either bond or they don't. If they don't, they behave (again, to a first aproximation) pretty much like perfect, elastic, frictionless spheres.

                  You can think of it this way: a large company will have a certain number of people die each year, and so we could define something like a mortal-attrition rate for the company. But if we try to extend our model to small companies, or even sole proprieterships, it breaks down. Bob of "Bob's Shoe Repair" may or may not die (most years he won't) but he will never have the 0.003% mortal-attrition rate we'd expect extrapolating from the large corporation.

                  Ah, but what we are trying to accomplish on the nanoscale is quite akin to the aims of what biology has been doing for a billion years or so. Biology hasn't built F-16's because there wasn't any evolutionary gain in building them (there not being any SAM-7's or Su-27's to compete against). But our nano/micro world has been teaming with (competing) life doing all sorts of interesting things (coral, ant colonies, bee hives, bacteria, yeast, fungi just to name a few examples) with close analogues to our aims in nano-technology. On the micro/nano scale of doing things efficiently, we haven't even made it to the stone age when compared to the biological world. Heck, we don't even have fire yet.

                  We may, to use your analogy, have to go through a phase of animal-labor before we develop maschines of our own. But you are wrong about the efficency of living things. The vast majority of "what they do" is centered around things like finding mates, spreading to and colonizing new environments, fighting other organisms, foraging for food, etc. that we don't want nanobots to do, any more than I want my car to go out and prowl for a mate, eat my neighbor's rose bushes, or speend the night out drag racing other cars to determine who's the big wheel in the neighborhood.

                  Mostly, I object to more of my tax dollars going to research into nano dreck (and fusion crap) instead of going to research towards more efficient power generation/solar generation/geothermal generation/waste heat utilization/home generation/efficient transportation/waste reduction/erosion prevention; all of which have a darn good chance of improving the state of the world during the next decade.
                  I, on the other hand, object to tax dolars being spent on short-term-returns things that ought to be paid for by private capital. I think tax dolars should be saved for the long-term we'll-need-this-someday-so-we-should-start-on-it-n ow stuff that otherwise won't get funded.

                  -- MarkusQ

                  • Thanks for the interesting discussion. Still some holes in your arguments:

                    WRT to the piston machine: Obviously when the pressure rises outside the piston, the piston is accelerated inward, however, the force * distance it is accelerated inward is the energy extracted. For nano-bots, that is going to be really really small due to the minute areas we're dealing with. Also, the spring needs to push the piston out before the next pressure wave hits, for high frequencies this means a stiffer spring, resulting in less energy extracted. Again, show me the power calculations.

                    Your intuition is wrong. Friction is a macroscopic effect, like colour or policical affiliation. Bellow a certain size, it doesn't apply, because the things you are dealing with don't have enough internal complexity to support it. With macroscale objects, there are many, many atoms that meet at the interface, and the sum of all their interactions is what we call friction. At the other extreme, when two atoms meet there are (obviously) only two atoms meeting. To a first aproximation, they either bond or they don't. If they don't, they behave (again, to a first aproximation) pretty much like perfect, elastic, frictionless spheres.
                    My intuition may be wrong but not for the reasons you give. There are also forces like electro-static friction and molecular forces. Disregarding that, do you seriously expect me to believe that our nano-bots will be manipulating the world at an atomic scale? At that scale, brownian motion, electro-static and chemical forces create a whole new set of problems. Different from friction, but just as bad, if not worse. On a more reasonable size scale (millions of atoms long), I still believe that friction is a big problem.
                    We may, to use your analogy, have to go through a phase of animal-labor before we develop maschines of our own. But you are wrong about the efficency of living things. The vast majority of "what they do" is centered around things like finding mates, spreading to and colonizing new environments, fighting other organisms, foraging for food, etc. that we don't want nanobots to do, any more than I want my car to go out and prowl for a mate, eat my neighbor's rose bushes, or speend the night out drag racing other cars to determine who's the big wheel in the neighborhood.
                    We don't have to take the whole organism. We can just crib their parts (mitochondria, flagella, digestive cycles etc.) and use them to assemble them other organisms. I'm not saying that that it'll be easy to do that. I'm just saying that the parts to get bio-nano-bots going are already designed, built and functioning. It's assembly that's the problem. With nano-bots, we don't have all the parts yet.
                    I, on the other hand, object to tax dolars being spent on short-term-returns things that ought to be paid for by private capital. I think tax dolars should be saved for the long-term we'll-need-this-someday-so-we-should-start-on-it-n ow stuff that otherwise won't get funded.
                    I don't have a problem with long term research or with short term research. I have a problem with one being funded with stupid sums of money to the exclusion of the other. BTW, what's paid for with private capital, isn't released for public use, it's kept for private gain.

                    Thanks again for the interesting discussion.


                    • Thanks for the interesting discussion.

                      Ditto.

                      Do you seriously expect me to believe that our nano-bots will be manipulating the world at an atomic scale?

                      Yes. That's what distinguishes nanotechnology from, say, MEMS. The whole point is to have atomically precise devices (eutactic machines if you prefer).

                      At that scale, brownian motion, electro-static and chemical forces create a whole new set of problems.

                      All of this and more is covered at length in Nanosystems [barnesandnoble.com], which you probably ought to take a look at.

                      WRT to the piston machine:...the spring needs to push the piston out before the next pressure wave hits, for high frequencies this means a stiffer spring, resulting in less energy extracted. Again, show me the power calculations.

                      For details on this point see chapter 6 (IIRC) of Nanomedicine [amazon.com]. In brief and partial answer to your spring-stiffness argument, just remember resonance--we know the frequency, etc. before hand and can design for it. When you add this to the facts that 1) the natural frequency of a system is inversely proportional to the scale, 2) the energy carried by a wave goes up with the square of frequency, 3) the power needed to run a machine drops as the inverse square of scale, it should (to a very rough first aproximation), be 10,000 times more effective to power a device with acoustic waves for every order of magnitude reduction in scale. Given that there have been simple ~10cm devices powered by anharmonic changes in barometric pressure, we should expect (all other things being equal, which of course they aren't) it to be on the order of 10^28 times more effective on the nanoscale.

                      -- MarkusQ

                    • I'll be sure to check out those two books. Sounds pretty interesting. Maybe they'll change my mind, but I doubt it: even with a good power source communication and organization pose serious problems for mecha-nanobots. For the time being I'll stick with my preference for bio-nanobots.

                      EnkduEOT

                    • >...communication and organization pose serious problems for mecha-nanobots

                      Agreed. I'm just not so sure that bio-nanobots won't have the same problems. It's a wonderful time to be alive if you enjoy tackling a little technical challenge now and then.

                      -- MarkusQ

    • Whilst you are right about the missing pieces for nanatechnology (and indeed I have no position on the feasibility of the components of which you speak) there are a number of "necessary" components for these nanotech objects to work and without all of them the system is not feasible. One of the necessary components is probably a micro turbine and so it is newsworthy when the advances are made for once they exist, the solving of the other components reduce the number of missing "necessary" components before we have sufficient technology to try the whole deal.
    • A turbine does not a generator make. Show me the electricity! Silicon ain't magnetic people. OK, magnetless generators exist, how about "coils" then? Show me the coils! Until I see a working, efficient, microsized generator, I don't see any of this happening.

      Funny you should mention that; a graduate student at MIT working on that very topic defended his thesis earlier this week. An old progress report [mit.edu] describes the basic idea. It's more difficult, but not impossible.

      As things get smaller and smaller, your perceived viscosity goes up and up.

      Although viscous drag is a problem with MEMS (another MIT student defended his thesis this week on efficient algorithms for calculating fluid drag on MEMS), the beauty of microfabrication is that as the characteristic length gets smaller, the Reynolds number drops, so the flow stays laminar. At 1 MHz, the boundary layer thickness is pretty small, so in fact you can model the fluid (air) as nearly inviscid. It's not uncommon for resonant MEMS devices to have a Q of 50 or more in air.

      The majority of damping in MEMS comes from squeeze-film damping, which occurs when you have a moving object suspended a small distance above the substrate. Motions of the object towards or away from the substrate cause fluid flow that generates a lot of damping; motions of the object parallel to the substrate cause a lot less damping. The micro-turbine is made out of 6 (!) wafers of silicon (which creates one hell of an alignment problem, by the way), so the turbine can be suspended well above the substrate. It also moves parallel to the substrate, rather than perpendicular to it. Of course, viscosity is still the ultimate limiting factor, but it's not as bad as you make it sound.

    • Umm, what about the working model from the previous article that makes 20W? If that ain't happened, I don't know what is. 20W is about 1/10 of what you can make with your legs for any usable period of time. The working model ran for 24 hours. It's problems were heat dissipation, but the same can be said for any heat engine. If you don't want to hook this thing up to make electricity, why not let it work as an air compressor or hydrolic motor? Power in any form is good. If the damn thing does not last long, shit can it, mass produced it's disposable. Apply where approriate.

      Silicon and high tempertures? Hmmm, ever heard of glass and ceramics? Oh yeah, I forgot they are made of ... silicon. Next.

      There will be improvemnts and inovations, there always are. The simplified drawing showed a radial inflow turbine. These have never worked well on a larger scale becuase particles reciculate in the blades and destroy them. Axial and radial outflow work better. So what? The next designs will have them if it's practical.

      Thanks for playing troll slashdot, please don't come again.

      • Umm, what about the working model from the previous article that makes 20W? If that ain't happened, I don't know what is. 20W is about 1/10 of what you can make with your legs for any usable period of time. The working model ran for 24 hours. It's problems were heat dissipation, but the same can be said for any heat engine. If you don't want to hook this thing up to make electricity, why not let it work as an air compressor or hydrolic motor? Power in any form is good. If the damn thing does not last long, shit can it, mass produced it's disposable. Apply where approriate.
        Yeah, but it wasn't powering anything was it? I don't see a picture of a 20W bulb being lighted do you? Where's the electricity?
        Silicon and high tempertures? Hmmm, ever heard of glass and ceramics? Oh yeah, I forgot they are made of ... silicon. Next.

        Silicon dioxide. I haven't heard of any chip fabricating techniques being used on ceramics yet. Anybody home?

        There will be improvemnts and inovations, there always are. The simplified drawing showed a radial inflow turbine. These have never worked well on a larger scale becuase particles reciculate in the blades and destroy them. Axial and radial outflow work better. So what? The next designs will have them if it's practical.
        There are still the problems of electrical generation and the problem of durability. And they are, in my opinion, going to be alot harder to overcome than just saying, "improvements will continue and it will soon be practical". Remember rotary engines? They only had one problem. The darn seals. And I don't see any Ford's with rotary engines yet...

        EnkiduEOT

  • I'm a Chicken Little.

    Although I love the idea of alternative means of obtaining energy, I do not cherish the idea of my nuclear powered cell phone failing a SCRAM shutdown and going critical while I'm using it.

    Of course, some dubious hacker could also send illegitimate SCRAM routines to force a reactor critical state, which is a great big can o worms in terms of personal safety, IMHO.

    And then there's the whole OS issue, too. Would you use an 18.1.2.5 kernel or an 18.0.2.4 kernel? Who would do the development and QA on such devices? Also, would an FO bug in hardware prove to be a mere mathematical nuisance, or the world's next 3 Micrometer Island?

    Who would use a Microsoft OS on such devices? System up time would take on a whole new meaning in the age of nuclear powering silicon devices.

    Then there would be the issue of the subversive cadre of hardware enthusiasts that try to get 10% more out of their AMD's Nucleon XP 24.4(TM) core by over clocking them, whilst taking the risk of drastically reducing their life spans as well as those of their neighbors.

    In conclusion, I will retain my Chicken Little viewpoint on this technology. The sky may indeed never fall down, but it doesn't hurt running around in circles believing that It Just Might.
    • There are no plans to make a microscopic nuclear reactor, according to the article. So there's nothing there going critical. Essentially they were talking about the kind of nuclear batteries that have been in use for a long time already on space craft and such.
      • When they described the nuclear batteries they specifically mentioned beta radiation. They vaguely state that beta radiation is "energetic electrons" and can be harnessed.

        I suspect what they may be refering to is a device that has a beta emitter and some compound that scintillates (emitts little flashes of light when hit by a beta particle) layered on it, and then a relatively ordinary photo-voltaic cell on top of that. Such a device is described on page 522 of James Bamford's "Body of Secretes", and he says that the device is now in use (for powering bugs that have to be small, require low power, and need to operate for as long as possible, and you can't go back to change the batteries).

        The more common nuclear battery has enough material to actually heat up, and runs a thermocouple.

        If the NSA is actually using beta radiation batteries, I wish they would commercialize that and have someone sell them. On one hand, we don't want nuclear materials to proliforate too much in everyday objects, because then the landfills start getting slightly hot and put low level contaminants into groundwater, etc. On the other hand, a certain number of people die every year from being in a house where the battery on the smoke detector has run out; perhaps these nuclear batteries could be approved only for smoke detectors.

        I want to use them to power my army of tiny robots that will go out at night and collect droped change around the parking meters downtown, hidding in the bushes and storm drains by day. My plan to lay around posting to slashdot all day while my robot army brings me a steady income will soon be complete !

  • Batteries stink (Score:3, Interesting)

    by olman ( 127310 ) on Saturday May 18, 2002 @04:26AM (#3541978)
    What strikes me as funny about all this is that it would be more efficient to run a tiny engine instead of using a battery. Engines have to deal with friction, which leads to waste heat. Batteries do generate a little heat, but that's it. In other words, it's not that the micro-engines are so great, it's that the batteries are so bad. Lithium-ion batteries are more user-friendly and a little bit more efficient than nickel-cadmium-batteries, but not by that much. Zinc-oxygen batteries are a real innovation, if only due to the fact that air's free. I'm not complaining, my hearing aid runs more than twice as long as with conventional batteries, but the Zinc-air battery prices are highway robbery.

    Until we learn to store electricity in a reasonable manner, wacky ideas like microengines will probably stay around. I didn't see much mention in the article about how to deal with the heat and friction of higher-rpm-than-conventional-gas-turbine, so we can safely assume this stuff is not going to appear next year in circuit city.
  • Ok, we all agree that microturbines are a great idea yes? and getting them from concept model to "actual 10 watt field unit" is gonna present a lot of challenges that probably haven't even been thought of. But really what we're talking about is a compact source of relatively efficient power right? Sort of like the frictionless flywheels I heard so much talk about around 15 years ago. You know, the ones we have in every house and car right now. Or go a bit further back to the "nuclear batteries" or similar technologies. I'm not saying it won't happen. I'm just saying I'm not holding my breath.

  • Why? (Score:2, Insightful)

    by gerardrj ( 207690 )
    Micro turbines on soldiers? First time they dove in the dirt, got wet, or accidentally covered the air intake, the thing would stop. Can you imagine how small the string must be that you wind around it to spin it back up?

    I also must ponder this: If you're thinking about putting a fuel like Hydrogen on the soldier, why not simply put a small fuel cell on them instead. It has NO moving parts, is quite efficient today, requires no new research, and works in any orientation as long as it gets air.

    This seems like a solution in search of a problem and funding.
    • What string? Just turn the key! : )

      Seriously...I have no idea why so many slashdot readers freak out every time there's a story about developing technology. The process of innovation is sometimes very disjointed - something, so seemingly unrelated may some day provide the missing link to a very complex puzzle. Some of it is noise and will go nowhere...but even so, the potential is still food for thought.

  • I really hope that those people from the middle-east finally adopt this standard. I had to sit behind someone wearing an old-school "normal" turbine during Star Wars, and it was quite annoying, to say the least.
  • "Mamba" [swbturbines.com] for model jet aircraft.

    3.5" in diameter, 7.5" long, one pound eleven ounces and it produces 11 pounds of thrust. The page at SWB Turbines [swbturbines.com] shows them in a 100-engine production run, having built all the turbine wheels and apparently machining everything out of aluminum bar stock as big as the engine- guess if you're charging $2400 an engine, you damned well machine the casing out of solid aluminum and not old soda pop cans ;D

    I sound like a PR flack, which I'm not- I've just long thought that the gas turbine is the best aircraft engine, and until yesterday I didn't know they made them this small. I mean, check out that 'Mamba' picture- how can you not think this is cool, that there's a working jet engine you can buy that fits in the palm of your hand, not an experiment but a commercial product with its own little market? Makes me want to start building F-15 models :)

    Now all I want is for them to start building a high-bypass version of the SWB-100 with a free turbine powering a shaft to drive an intake fan... yes I know you could do that with an Allison or even a Garrett but that's so drastically overpowered for what I'm thinking of...

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