Getting a 43% average in a course doesn't mean you learned 43% of what was expected of you. Did you know that mathematically inclined professors (like in engineering) know that if the grade distribution is compressed up at the top of the range, with 15% of the class getting 100%, then you are clipping off a section of the distribution. You can't actually distinguish the good students from the stars. If you want to be able to see the full range of student ability then your grade distribution should have a tail at the high end as well as the low. That means lower averages.
Additionally, a harder exam will challenge all students. If you get a perfect score on an exam you might feel good, but you haven't actually learned how much you know the material. You just know you know it better than you were tested on.
A 43% was a B+? So the class was graded on a curve and you didn't like the numerical value that you got? Cry me a river.
as much energy to make as you get by burning it?
on
Ethanol From Waste Straw
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· Score: 2, Insightful
People seem to think that this means that you aren't gaining anything by making EtOH from lignocellulose.
Consider the energy content of 1 ton of straw, and we'll just call that 1 unit.
Into this process you put 2 units of straw, and get out 1 unit of energy. So you get out the energy equivalent of one unit of straw.
The process isn't that efficient, true. You are consuming 1 unit of energy for every 1 unit you generate. But you're still coming out ahead, because you're using STRAW FOR ENERGY. It's essentially free. The dominant cost of corn stover (the straw in discussion) is transporting it to the refinery.
I hate to be repetative, but a lot of people are missing the point. To convert 1 unit of input to 1 unit of output can require an additional 1 unit of input and still be economically reasonable if your inputs are inexpensive.
I just got back from the Biotechnology Industry Organization world congress conference, which was all about this technology. It's certainly got a ways to go yet, but it's not a fundamentally broken concept just because it requires 2 tons of corn stover to produce EtOH equivalent to 1 ton.
The handlebar controls just make me think even more that the designers are clueless. Think about how the segway balance system works. Think about how handlebar accelerators work. You twist the accelerator, the device accelerates under you. This shifts your center of gravity backwards relative to the wheel. You tip over backwards. The segway system moves and balances by automatically staying under your center of gravity. It moves so that it stays upright. I don't see how you can decouple that balance mechanism from the acceleration and not fall down. And I don't see any evidence in this press release of any engineering thought going into it. Nor did I see it in the popular science article a few months ago. Nor in the Forbes article today. It looks very pretty, but it also looks like a human eating food processor.
It could maybe work if, at a standstill, you are sitting forward of the wheel with the landing gear down. But your acceleration is still limited such that the wheel can never get ahead of your center of mass. And if your center of mass starts out ahead of the wheel, then your ability to stop suddenly at low speeds (stop and go traffic) is really compromised, because you'd flip forwards.
I saw this in Popular Science a while ago and still have the same objections. I can't see how it could actually work at highway speeds. Think about it. The way the segway-like acceleration mechanism works is that the vehicle moves to stay underneath you. You accelerate by leaning forward, forcing the vehicle to catch up. If you want to accelerate fast enough reach highway speed without pissing off your fellow drivers you will need to lean forward pretty hard, but then what happens if the car in front of you stops suddenly while you are still accelerating? You brake by leaning back. But if you are in a hard acceleration mode where you're center of mass is ahead of the Embrio? Until it gets underneath you, you will be unable to tell it to stop.
I just think the segway balance mechanism becomes unstable at the kind of accelerations you need to avoid being a menace on the highway. The presense of that small retractable front wheel will still not allow it to accelerate like a highway vehicle.
Of course, the thing to realize is that the Embrio only exists as a pretty CG picture. I had the strong impression from the Popular Science blurb that it was designed by artists. The PopSci blurb quoted them as saying something like "we can't wait to find someone to build it for us!"
From their press release: "Technology will be used to harness the laws of physics"
Slashdot Mirror
Getting a 43% average in a course doesn't mean you learned 43% of what was expected of you. Did you know that mathematically inclined professors (like in engineering) know that if the grade distribution is compressed up at the top of the range, with 15% of the class getting 100%, then you are clipping off a section of the distribution. You can't actually distinguish the good students from the stars. If you want to be able to see the full range of student ability then your grade distribution should have a tail at the high end as well as the low. That means lower averages.
Additionally, a harder exam will challenge all students. If you get a perfect score on an exam you might feel good, but you haven't actually learned how much you know the material. You just know you know it better than you were tested on.
A 43% was a B+? So the class was graded on a curve and you didn't like the numerical value that you got? Cry me a river.
People seem to think that this means that you aren't gaining anything by making EtOH from lignocellulose.
Consider the energy content of 1 ton of straw, and we'll just call that 1 unit.
Into this process you put 2 units of straw, and get out 1 unit of energy. So you get out the energy equivalent of one unit of straw.
The process isn't that efficient, true. You are consuming 1 unit of energy for every 1 unit you generate. But you're still coming out ahead, because you're using STRAW FOR ENERGY. It's essentially free. The dominant cost of corn stover (the straw in discussion) is transporting it to the refinery.
I hate to be repetative, but a lot of people are missing the point. To convert 1 unit of input to 1 unit of output can require an additional 1 unit of input and still be economically reasonable if your inputs are inexpensive.
I just got back from the Biotechnology Industry Organization world congress conference, which was all about this technology. It's certainly got a ways to go yet, but it's not a fundamentally broken concept just because it requires 2 tons of corn stover to produce EtOH equivalent to 1 ton.
The handlebar controls just make me think even more that the designers are clueless. Think about how the segway balance system works. Think about how handlebar accelerators work. You twist the accelerator, the device accelerates under you. This shifts your center of gravity backwards relative to the wheel. You tip over backwards. The segway system moves and balances by automatically staying under your center of gravity. It moves so that it stays upright. I don't see how you can decouple that balance mechanism from the acceleration and not fall down. And I don't see any evidence in this press release of any engineering thought going into it. Nor did I see it in the popular science article a few months ago. Nor in the Forbes article today. It looks very pretty, but it also looks like a human eating food processor.
It could maybe work if, at a standstill, you are sitting forward of the wheel with the landing gear down. But your acceleration is still limited such that the wheel can never get ahead of your center of mass. And if your center of mass starts out ahead of the wheel, then your ability to stop suddenly at low speeds (stop and go traffic) is really compromised, because you'd flip forwards.
I saw this in Popular Science a while ago and still have the same objections. I can't see how it could actually work at highway speeds. Think about it. The way the segway-like acceleration mechanism works is that the vehicle moves to stay underneath you. You accelerate by leaning forward, forcing the vehicle to catch up. If you want to accelerate fast enough reach highway speed without pissing off your fellow drivers you will need to lean forward pretty hard, but then what happens if the car in front of you stops suddenly while you are still accelerating? You brake by leaning back. But if you are in a hard acceleration mode where you're center of mass is ahead of the Embrio? Until it gets underneath you, you will be unable to tell it to stop.
I just think the segway balance mechanism becomes unstable at the kind of accelerations you need to avoid being a menace on the highway. The presense of that small retractable front wheel will still not allow it to accelerate like a highway vehicle.
Of course, the thing to realize is that the Embrio only exists as a pretty CG picture. I had the strong impression from the Popular Science blurb that it was designed by artists. The PopSci blurb quoted them as saying something like "we can't wait to find someone to build it for us!"
From their press release:
"Technology will be used to harness the laws of physics"
Yes, dear. I'm sure it will.
the same way 'not living in a police state' allows terrorism.