Biofuels a Greater Greenhouse Threat

[rushmc 23]

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Paper is also cellulosic material, and we're just throwing that stuff away by the megaton.

True, but that is not where they are talking about it coming from.

"America will never be destroyed from the outside,
if we falter and lose our freedoms,
it will be because we destroyed ourselves."
Abraham Lincoln

[rushmc 23]

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>The effects of removing cellulosic materials from corn fields . . .

Why take it from corn fields? Why not use paper, cardboard, rice hulls, waste wood or grass clippings? Why not grow switchgrass (which grows anywhere) and use that?

As we've said before, there will be no one magic bullet that solves all our fuel problems. Corn based ethanol isn't a very good solution; it's just marginally better than oil from a source perspective. Cellulosic ethanol is a lot better. Biodiesel, biogas and syngas will also be options.

>The effects of removing what becomes compost (humas) is not totoally
> known either.

So replace it with sterilized manure from sewage processing plants, hog farms and dairies.

I agree there are many sources but the biggest volumes spoke of come from the fields. And in any event, where it is taken from the fields (where not currently taken) my point is correct.

For every action is a reaction.

Look, I am not against it but realize what will happen.

"America will never be destroyed from the outside,
if we falter and lose our freedoms,
it will be because we destroyed ourselves."
Abraham Lincoln

[billvon 3,132]

>How about high efficiency piezo crystals embedded in all
>vibrating/moving/flapping objects.

Been done, but so far they're getting on the order of 10mW/m^2 in a 6mph breeze. In terms of wind power, swept area is everything - and flags have a very low swept area.

However, such amounts of power do have the potential to do things like keep cellphones charged or run remote sensors.

[kallend 2,184]

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>How about high efficiency piezo crystals embedded in all
>vibrating/moving/flapping objects.

Been done, but so far they're getting on the order of 10mW/m^2 in a 6mph breeze. In terms of wind power, swept area is everything - and flags have a very low swept area.

However, such amounts of power do have the potential to do things like keep cellphones charged or run remote sensors.

You're forgetting that this is election year. All those politicians wrapping themselves in the flag could power a small city for a month.

...

The only sure way to survive a canopy collision is not to have one.

[billvon 3,132]

>s well as on the other end of the size scale – wearable piezoelectric ZnO nanowires . . .

All those technologies work, but with the exception of heel strike, generate very small amounts of power (i.e. far less than a cellphone in standby.) Heel strike can generate close to a watt on concrete, but we wondered how many people would be willing to put their cellphone on their foot or run wires up their legs.

[Channman 2]

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Paper is also cellulosic material, and we're just throwing that stuff away by the megaton.

Well maybe to some degree we are still tossing paper to landfills. I just finished building a custom home in League City, and I used recycled paper i.e. cellulosic material that was treated with Boric acid as insullation for my walls and attic.

Not only does it sound proof the home, it was fun pumping that stuff in. One person does the blowing and packing while another person vaccums the rebound which is recirculated and reused.

[nerdgirl 0]

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>s well as on the other end of the size scale – wearable piezoelectric ZnO nanowires . . .

All those technologies work, but with the exception of heel strike, generate very small amounts of power (i.e. far less than a cellphone in standby.) Heel strike can generate close to a watt on concrete, but we wondered how many people would be willing to put their cellphone on their foot or run wires up their legs.

Bill –

I think you may be confusing previous work w/those I cited. Rotary cuff (magnet) based heel strikes systems, etc. generated 2-10 Watts.

Otoh, one of the examples hasn’t been published yet and the other was published last month in Nature. Wang and co-workers grew ZnO nanowires on Kevlar. The microfiber-nanowire hybrid system builds on the nanogenerators that Wang, et al., described in Science in April 2007. Actually the biggest pragmatic problem with ZnO nanowires integrated into clothing at the moment isn’t amps, it’s reactivity w/H2O, i.e., you can’t wash them & they would ‘short circuit’ in the rain.

Nonetheless, rather than dismissing out of hand, it may be worth to revisit some now-infamous dismissals of emerging technology:

“I think there's a world market for about 5 computers.” (Thomas J. Watson, Chairman of the Board, IBM, circa 1948)

“It would appear that we have reached the limits of what it is possible to achieve with computer technology, although one should be careful with such statements, as they tend to sound pretty silly in 5 years.” (John Von Neumann, circa 1949)

“But what is it good for?” (Engineer at the Advanced Computing Systems Division of IBM, commenting on the microchip, 1968)

“There is no reason for any individual to have a computer in his home.” (Ken Olson, President, Digital Equipment Corporation, 1977)

“640K ought to be enough for anybody.” (Bill Gates, 1981)

Or maybe it's just the difference between scientists & engineers?

VR/Marg

Act as if everything you do matters, while laughing at yourself for thinking anything you do matters.
Tibetan Buddhist saying

[billvon 3,132]

>Rotary cuff (magnet) based heel strikes systems, etc. generated 2-10 Watts.

So far I've seen only one claim of power over 1 watt (via an MIT study) and it had a caveat along the lines of "the size and weight of the power conversion device adversely affected the user's gait." Think a ten pound generator/gearing assembly on the side of your foot. The calculated best you can do without affecting the user's gait is about 5-8 watts per the 1996 IBM wearable-PC study - so 10 watts sounds a little optimistic. I mean, based on the efficiency of the body, you'd have to generate another 70 watts internally to power a 10 watt heel strike device. Given that we generate about 160 watts when walking slowly, that's a big increase.

The best practical device I've seen so far has been by SRI international, where an elastomeric stack generated .8 watts per shoe per strike. They think they can get to a watt.

>Nonetheless, rather than dismissing out of hand . . .

Oh, I'm not dismissing it at all! Indeed, as power required for voice-only cellphones comes down, many of these technologies may indeed become more useful. But in terms of what's been demonstrated (and there have been a LOT of attempts at doing so) we have a ways to go before human energy harvesting is easy/practical/unobtrusive.

(Of course, if you really want to do a human powered device, there are any number of crank generators/pedal generators out there.)