I am a chemosensory psychophysicist, but I work in taste/chemesthesis, not smell. That having been said, I was in the room when Keller and Vosshall presented the following at the Association for Chemoreception Sciences meeting in 2004.
A PSYCHOPHYSICAL TEST OF THE VIBRATION THEORY OF OLFACTION Keller A., Vosshall L.B. Laboratory of Neurogenetics and Behavior, Rockefeller University, New York, NY
At present no satisfactory theory exists to explain why a given molecule has a particular smell. A recent book about the physiologist Luca Turin has generated new interest in the theory that the smell of a molecule is determined by its intramolecular vibrations rather than by its shape. We present the first psychophysical experiments in humans that test key predictions of this theory. The results suggest that molecular vibrations alone cannot explain the perceived smell of a chemical. Specifically, we have found that: (i) in a component identification task no vanilla odor character was detected in the mixture of benzaldehyde and guaiacol (ii) odor similarity ratings did not reveal that even and odd numbered aldehydes form two odor classes and (iii) naive subjects who could easily discriminate the smell of two molecules that differ in shape but not in molecular vibration failed to discriminate two molecules with similar shape but different molecular vibrations in three different experimental paradigms (similarity rating, duo-trio test, triangle test). Taken together our findings are consistent with the idea that the smell of a molecule is determined by its shape but we found no evidence that the smell of a molecule is influenced by its vibrational properties.
They subsequently published their findings in Nature Neuroscience.
Keller A, Vosshall LB. A psychophysical test of the vibration theory of olfaction. Nat Neurosci. 2004 Apr;7(4):337-8.
At present, no satisfactory theory exists to explain how a given molecule results in the perception of a particular smell. One theory is that olfactory sensory neurons detect intramolecular vibrations of the odorous molecule. We used psychophysical methods in humans to test this vibration theory of olfaction and found no evidence to support it.
The short version is that the data do not support Luca Turin's speculation.
.. then gas stations will have to be very very big. You'd lose most of the benefits driving around trying to find the right pump.
Sorry. I think you might have missed the point.
He wasn't talking about 37 different niche fuels - he's talking about using a bunch of different technologies that each contribute a small percentage toward reducing our petroleum consumption instead of waiting/hoping for a one-size fits all magic bullet.
For example, what if every state required E10 like NY,CT, HI and MN already do?
Now imagine that states required that all diesel be a B5 blend like Portland, OR or B2 like MN has done. That's millions of gallons of petrodiesel that the trucking industy isn't burning.
Now imagine that Detroit started selling Americans the diesels they already build. Diesels get about 30% better mileage (give or take) than a comparable gas engine. If even 20% of the cars on the road were diesels, that would save a small but very real percentage right there.
Now imagine that mass transit rideership use increases by just 5%. That's how many millions of cars that aren't on the road?
My wife and I just moved. Her commute is now under 5 miles compared to 25 before.
Nor do you need to focus just on transportation.
My brother in law's home heating oil supplier offers a B15 blend for a *lower* price than straight petroleum based home heating oil. At our old house, I switched every fixture that was feasible to a CF bulb and electricity usage dropped by 20 or 30%.
We shouldn't wait for a magic bullet when lots of little choices can, when aggregated, get us closer to where we want to be.
It is the opinion of every single person in the industry that there is no real possibility of replacing gasoline with ethanol. It would take the entire corn harvest of the United States to make that much ethanol
The whole ethanol thing is just another wall street fad that's brought in a bunch of suckers.
Why do you assume that corn is the only possible feedstock that can be used to make ethanol? Yeasties don't care about the source of the simple sugars.
You can extract the sugar for grain to make ethanol and feed the "spent" grain to livestock. How many megatons of raw corn do we feed beef cattle in the US?
Or you could grow sugar beets - the US is the 3rd largest producer of sugar beets in the world.
Or we could import sugar cane based ethanol from Brazil.
Or we figure out how to get simple sugars from cellulose cheaply.
In other words, you are way too quick to assume that the only way to make liquid biofuels is from corn.
The EROI for ethanol is 1.67 to 1 while the EROI for biodiesel is 3.2 to 1. That is, both have a positive energy balance. But that still doesn't change the fact that corn and soy are crummy energy crops. It just so happens that they have huge agribusiness lobbies behind them. Of course, trading ExxonMobil and Chevron for ADM and Monsanto isn't a big improvement.
That having been said, ethanol and biodiesel don't have to come from these feedstocks. The folks at SUNY ESF have figured out how extract simple carbs from cellulose for fermentation using only heat and pressure with only water as a solvent. And then you have the enzyme approach the Iogen folks in Canada are pushing. Likewise, the algae biodiesel folks are really close to turning the corner.
My point? Just because corn and soy based biofuels aren't a magic bullet doesn't mean that liquid biofuels don't have an important place in our energy policy.
Disclaimer: I drive a 2003 VW TDI that gets 46mpg lifetime (paper log, not dash readout). By using the B20 pump near my house, I can go 57.5 miles for every gallon of petrodiesel consumed.
No doubt. There's still nothing on a computer that can simulate the SMELL of a recently discharged weapon either...
Heh. Funny you should mention that. I was a senior sensory scientist at DigiScents and I had a working iSmell prototype on my desk.
And in my opinion, the spent brass smell we had was one of our five best smells. I think the official name was gunsmoke, but man, it smelled just like a spent shell casing.
Ironically, DoD wanted to pay us some reasonably sized chunk of money to develop 6 smells for their simulators, but our management guys never followed up because they were too busy trying to hit the dot-com homerun instead of winning the game with RBIs and stand up doubles.
Have you ever seen a biodiesel vehicle in operation? White smoke pumping out. I see one everyday. My VW doesn't smoke unless the engine has coldsoaked for a couple of days below freezing. And then the smoke clears up within the first minute.
Have you ever smelled a biodiesel vehicle in operation or at rest? Uhg! What a stench. Why yes I have. I've even gotten down on all fours and sniffed my tailpipe. It has a distinct smell, but it doesn't smell like fries or eggrolls, and it smells much much better than the sulfur laden petrodiesel we get here in New England.
Have you ever driven a biodiesel vehicle? They are a bit quieter than when running on regular diesel but they also lack power compared to when running on regular diesel. I drive one everyday. It's certainly not lacking in power and the increased cetane rating makes the engine run much smoother. The BTU content of biodiesel is about 95% of that of petrodiesel. So does it get slightly worse mileage? Sure. But it isn't the anemic dog you make it out to be.
Biodiesel may become more widely used in commercial or off-road applications but, it will never take off for highway vehicles. My commute is 90 miles by highway and I use biodiesel. I know of two retail biodiesel pumps just off I91 (one in Holyoke and one in Brattleboro). I think you are misinformed.
Finally, I have a question for you Mr. Anonymous Coward. You seem rather put off by your biodiesel exposure. Is that just armchair experience from surfing or have your actually driven a BD powered vehicle. If so, was it a modern german turbodiesel like my '03 Jetta or was it a 20 year old out of tune beater MB hippiemobile. No offense to the old-school MB diesel hippies, but they make the rest of us look bad.:)
"Were any modifications neccessary to run on biodiesel."
No modifications were needed on my stock 2003 Jetta TDI. Better yet, I can 'splash-blend' on the go - that is, I can add 5 gal of B100 to my car and then top off with regular #2 petrodiesel at the pump. They mix completely in the fuel tank and no special blending is needed.
As far a warrantee issues, my dealer knows I use biodiesel (the big sticker on the back of my car might have something to do with that) and frankly, they don't care.
VWoA officially allows up to a B5 blend and rumor has it B20 approval is coming shortly. Like all fuels, petro- or bio-, VW doesn't cover "misfueling" with bad quality fuel. If a tank of bad petrodiesel damages your injection pump, the retailer, not VW pays for the repair. So using biodiesel really isn't an issue as far as that is concerned.
Second, biodiesel is 78% carbon neutral with regard to greenhouse gas emissions (see previous pdf). That is because the majority of the carbon emitted when you burn a gallon of biodiesel was captured from the atmosphere when you grew the plant to make the vegetable oil. However, the methanol used to make the biodiesel (fatty acid methyl ester) is made from natural gas, at least in the US. You could make 100% renewable ethyl ester biodiesel from ethanol, or make methanol from landfill recovery biogas, but we don't currently.
Third, soy and corn oil are crummy crops to make biodiesel from. But that's where the lobbying money is right now. Other plants have much higher yields. http://journeytoforever.org/biodiesel_yield.html
Forth, no, it isn't a question of "food or fuel"? We can do both! Whenever you hear that argument ask yourself whether the person is well meaning but misinformed, or as been happening recently, is part of astroturf campaign to preserve the status quo of the petroleum economy.
I can't speak to this newest report, but Pimental's work has been repeatedly critiqued, and one of the main compliants it that he uses out of date numbers for yield and conversion efficiency:
All that having been said, Pimental is right that soy and corn alone cannot replace our petroleum addiction. You can read more about this in the archives at TDIclub.com.
The benefits of ethanol as a renewable energy source are very debateable. I'd bet bio-diesel is a lot more energy positive though.
Ethanol is *also* energy positive. Pimental's old calculations have been thoroughly debunked.
Corn based ethanol doesn't return quite as much energy as BD, but it still has a positive energy balance on the order of 1.67 units out for every unit in. Compare this to 3.2 units out for every unit in for biodiesel.
Then compare both of those to.80 for gasoline and.85 for diesel and biofuels clearly win the energy balance arguement.
More reading:
http://www.mda.state.mn.us/ethanol/balance.html
http://www.usda.gov/oce/oepnu/aer-814.pdf
"Another promising candidate is bio-diesel; on the plus side you can easily convert a diesel engine today - on the down side harvesting and processing the crops "costs" more energy (according to some studies) than you're getting in the biodiesel from the solar energy the crops grew on."
You've got the right idea but you've got a couple of details wrong.
a)NO Conversion is needed to run Biodiesel in a modern diesel. You're confusing BD with WVO, which does require conversion.
b)I know of no studies that claim biodiesel has a negative energy balance. You're thinking of ethanol, not biodiesel, and even then those calculations have been refuted with newer data.
"Please note that we're NOT talking about corn ethanol, which a highly subsidized and environmentally contentious product due to high energy costs of growing and harvesting corn."
Actually, even corn-ethanol has a positive energy balance these days. Much of the confusion dates back to some old calculation's by Pimental at Cornell that found corn-ethanol had a negative energy balance when in fact more recent USDA numbers show that corn-ethanol produces 67% more energy that it takes to produce it.
Still, biodiesel blows ethanol out of the water in terms of energy balance. And that's making B100 from soy. Imagine the energy return if we made it from dual use crops like mustard or better yet from algae.
Algae source biodiesel grown on 15,000 sq. miles could completely displace petroleum transporation fuels in the US. Don't believe me? Read Mike Briggs' analysis for yourself:
http://www.unh.edu/p2/biodiesel/article_alge.htm l
Driving a modern VW or MB diesel whether or not you ever plan to use a single drop of domestically produced biodiesel is a good place to start.
My 2003 Jetta TDI has 40862 miles on it and I've used 832.7 gallons of diesel (and 56.9 gallons of biodiesel) thus far. For those of you keeping score at home, that's about 45.93 mpg over the life of the car. Not too shabby.
Why wait 15-20 years for hydrogen when we can start reducing our dependence on foreign oil NOW?
" Biodiesel doesn't have anything to do with cutting down emissions. You're still burning hydrocarbons."
Actually, regardless of whether or not Darryl Hannah is a moron, you are wrong.
Because the carbon in the vegetable oil used to make biodiesel is already part of the carbon cycle (opposed to having been sequestered underground for millions of years), biodiesel does not, for the most part, contribute to a NET INCREASE in carbon dioxide.
In fact, research by the US DOE suggests that biodiesel use cuts net CO2 emissions by 78%.
http://www.ott.doe.gov/pdfs/biodieselfuel.pdf
The reason it isn't 100% is because the methanol reacted with the veggie oil to make the methyl ester comes from petroleum in the US. You can make ethyl ester biodiesel using non-petrochemical based ethanol, but the process control is less forgiving.
"But it would have to remain a separate product becauase petroleum oil and vegatable oils aren't miscible. "
Except that biodiesel *isn't* vegetable oil. It is a fatty acid methyl ester (FAME) *made* from vegetable oil. Not the same thing.
I 'splash-blend' biodiesel and petro diesel in my TDI all the time. Pour 5 gallons of B100 into the tank and then top off the rest of the tank with petrodiesel. This is standard practice in the BD community.
And besides, then I get to wear one of these neato t-shirts.
Seriously, I like that SAE is encouraging this sort of blue-sky stuff, but sometimes I wonder if in general these sort of events encourage average Joe to assume high mileage vehicles and renewables are 10 or more years away.
High mileage vehicles are here *now*. Renewables are here *now*. Let's use 'em.
On my last 2 tanks, I drove 1156 miles on 13.24 gallons of diesel blended on the fly with 10 gallons of biodiesel. That's 50 mpg or 87 miles per petrogallon. Not too shabby.
It may not be 1700mpg, but it is a step in the right direction and it's here now. Help spread the word.
" I'm sorry if my vehicle of choice isn't the most environmentally-minded design, but you forget how many other vehicles that are equally as bad for the environment are often left out of these arguments-ANY MUSCLE CARS, Mustang, Camaro, Corvette...All of these cars guzzle gas just as much as any SUV, and some are worse, in fact. "
Bzzt. Thank you for playing.
2004 'Vette gets 19/28 mpg with the manual. (Anyone buying an auto 'vette should be beaten.)
Look. If you *need* an SUV, fine. But the muscle car issue is a weak rationalization at best and comes across as a disingenous red herring for the more cynically minded.
Somehow I suspect a Passat TDI would haul all your stuff and get *twice* the mileage of your Explorer, but hey, only chicks drive veedubs, right?
Actually, maybe you could learn a little humility because Grade D is in fact a legitimate grade of beef.
The Prime/Choice/Select/etc grades you were refering to is a function of both maturity and marbling. The letter grades refer to the maturity of the carcass. Specifically, Prime/Choice/Select/Standard are always Grade A or B. However, Commercial/Utility/Cutter and Canner can be of Grades C through E.
Thus, if I'm buying commercial grade beef as retail estabilishment, I sure want to know if it is Grade C, D, or E to make sure I'm not getting ripped off by the supplier.
OS X is a proprietary, largely untested OS with commercial support and a large number of commercial applications coming to it in the near future. It is BSD-based. The development team focuses mostly on the GUI.
Ummm. No. OSX is really NeXTstep 6.1 with a macintosh application environment thrown in. NeXTstep is a proven stable OS that predates Linux by at least 3 years. Furthermore, the core foundation of OSX, known as Darwin is also open source.
Slashdot Mirror
I am a chemosensory psychophysicist, but I work in taste/chemesthesis, not smell. That having been said, I was in the room when Keller and Vosshall presented the following at the Association for Chemoreception Sciences meeting in 2004.
A PSYCHOPHYSICAL TEST OF THE VIBRATION THEORY OF OLFACTION
Keller A., Vosshall L.B. Laboratory of Neurogenetics and Behavior,
Rockefeller University, New York, NY
At present no satisfactory theory exists to explain why a given
molecule has a particular smell. A recent book about the physiologist
Luca Turin has generated new interest in the theory that the smell of a
molecule is determined by its intramolecular vibrations rather than by
its shape. We present the first psychophysical experiments in humans
that test key predictions of this theory. The results suggest that
molecular vibrations alone cannot explain the perceived smell of a
chemical. Specifically, we have found that: (i) in a component
identification task no vanilla odor character was detected in the mixture
of benzaldehyde and guaiacol (ii) odor similarity ratings did not reveal
that even and odd numbered aldehydes form two odor classes and (iii)
naive subjects who could easily discriminate the smell of two molecules
that differ in shape but not in molecular vibration failed to discriminate
two molecules with similar shape but different molecular vibrations in
three different experimental paradigms (similarity rating, duo-trio test,
triangle test). Taken together our findings are consistent with the idea
that the smell of a molecule is determined by its shape but we found no
evidence that the smell of a molecule is influenced by its vibrational
properties.
They subsequently published their findings in Nature Neuroscience.
Keller A, Vosshall LB. A psychophysical test of the vibration theory of olfaction. Nat Neurosci. 2004 Apr;7(4):337-8.
At present, no satisfactory theory exists to explain how a given molecule results in the perception of a particular smell. One theory is that olfactory sensory neurons detect intramolecular vibrations of the odorous molecule. We used psychophysical methods in humans to test this vibration theory of olfaction and found no evidence to support it.
The short version is that the data do not support Luca Turin's speculation.
.. then gas stations will have to be very very big. You'd lose most of the benefits driving around trying to find the right pump.
Sorry. I think you might have missed the point.
He wasn't talking about 37 different niche fuels - he's talking about using a bunch of different technologies that each contribute a small percentage toward reducing our petroleum consumption instead of waiting/hoping for a one-size fits all magic bullet.
For example, what if every state required E10 like NY,CT, HI and MN already do?
Now imagine that states required that all diesel be a B5 blend like Portland, OR or B2 like MN has done. That's millions of gallons of petrodiesel that the trucking industy isn't burning.
Now imagine that Detroit started selling Americans the diesels they already build. Diesels get about 30% better mileage (give or take) than a comparable gas engine. If even 20% of the cars on the road were diesels, that would save a small but very real percentage right there.
Now imagine that mass transit rideership use increases by just 5%. That's how many millions of cars that aren't on the road?
My wife and I just moved. Her commute is now under 5 miles compared to 25 before.
Nor do you need to focus just on transportation.
My brother in law's home heating oil supplier offers a B15 blend for a *lower* price than straight petroleum based home heating oil. At our old house, I switched every fixture that was feasible to a CF bulb and electricity usage dropped by 20 or 30%.
We shouldn't wait for a magic bullet when lots of little choices can, when aggregated, get us closer to where we want to be.
It is the opinion of every single person in the industry that there is no real possibility of replacing gasoline with ethanol. It would take the entire corn harvest of the United States to make that much ethanol
The whole ethanol thing is just another wall street fad that's brought in a bunch of suckers.
Why do you assume that corn is the only possible feedstock that can be used to make ethanol? Yeasties don't care about the source of the simple sugars.
You can extract the sugar for grain to make ethanol and feed the "spent" grain to livestock. How many megatons of raw corn do we feed beef cattle in the US?
Or you could grow sugar beets - the US is the 3rd largest producer of sugar beets in the world.
Or we could import sugar cane based ethanol from Brazil.
Or we figure out how to get simple sugars from cellulose cheaply.
In other words, you are way too quick to assume that the only way to make liquid biofuels is from corn.
The EROI for ethanol is 1.67 to 1 while the EROI for biodiesel is 3.2 to 1. That is, both have a positive energy balance. But that still doesn't change the fact that corn and soy are crummy energy crops. It just so happens that they have huge agribusiness lobbies behind them. Of course, trading ExxonMobil and Chevron for ADM and Monsanto isn't a big improvement.
That having been said, ethanol and biodiesel don't have to come from these feedstocks. The folks at SUNY ESF have figured out how extract simple carbs from cellulose for fermentation using only heat and pressure with only water as a solvent. And then you have the enzyme approach the Iogen folks in Canada are pushing. Likewise, the algae biodiesel folks are really close to turning the corner.
My point? Just because corn and soy based biofuels aren't a magic bullet doesn't mean that liquid biofuels don't have an important place in our energy policy.
Disclaimer: I drive a 2003 VW TDI that gets 46mpg lifetime (paper log, not dash readout). By using the B20 pump near my house, I can go 57.5 miles for every gallon of petrodiesel consumed.
Heh. Funny you should mention that. I was a senior sensory scientist at DigiScents and I had a working iSmell prototype on my desk.
And in my opinion, the spent brass smell we had was one of our five best smells. I think the official name was gunsmoke, but man, it smelled just like a spent shell casing.
Ironically, DoD wanted to pay us some reasonably sized chunk of money to develop 6 smells for their simulators, but our management guys never followed up because they were too busy trying to hit the dot-com homerun instead of winning the game with RBIs and stand up doubles.
Biodiesel really is amazing!
Bzzzt. Back to intro physics for you. To quote MC Hawking:
The earth's not a closed system' it's powered by the sun,
so fsck the damn creationists, Doomsday get my gun!"
Biodiesel is just solar energy, in liquid form.
Unless you knew this, in which case, if you were making a joke, you should have used a smiley.
I see one everyday. My VW doesn't smoke unless the engine has coldsoaked for a couple of days below freezing. And then the smoke clears up within the first minute.
Have you ever smelled a biodiesel vehicle in operation or at rest? Uhg! What a stench.
Why yes I have. I've even gotten down on all fours and sniffed my tailpipe. It has a distinct smell, but it doesn't smell like fries or eggrolls, and it smells much much better than the sulfur laden petrodiesel we get here in New England.
Have you ever driven a biodiesel vehicle? They are a bit quieter than when running on regular diesel but they also lack power compared to when running on regular diesel.
I drive one everyday. It's certainly not lacking in power and the increased cetane rating makes the engine run much smoother. The BTU content of biodiesel is about 95% of that of petrodiesel. So does it get slightly worse mileage? Sure. But it isn't the anemic dog you make it out to be.
Biodiesel may become more widely used in commercial or off-road applications but, it will never take off for highway vehicles.
My commute is 90 miles by highway and I use biodiesel. I know of two retail biodiesel pumps just off I91 (one in Holyoke and one in Brattleboro). I think you are misinformed.
Finally, I have a question for you Mr. Anonymous Coward. You seem rather put off by your biodiesel exposure. Is that just armchair experience from surfing or have your actually driven a BD powered vehicle. If so, was it a modern german turbodiesel like my '03 Jetta or was it a 20 year old out of tune beater MB hippiemobile. No offense to the old-school MB diesel hippies, but they make the rest of us look bad.
I've used a mix of commercial ASTM spec biodiesel and homebrew biodiesel that my friend and I have made in our 'Appleseed reactor'.
Appleseed Plans - http://www.biodieselcommunity.org/appleseedproces
The parts kit - http://www.biodieselwarehouse.com/ $229
"Were any modifications neccessary to run on biodiesel."
No modifications were needed on my stock 2003 Jetta TDI. Better yet, I can 'splash-blend' on the go - that is, I can add 5 gal of B100 to my car and then top off with regular #2 petrodiesel at the pump. They mix completely in the fuel tank and no special blending is needed.
As far a warrantee issues, my dealer knows I use biodiesel (the big sticker on the back of my car might have something to do with that) and frankly, they don't care.
VWoA officially allows up to a B5 blend and rumor has it B20 approval is coming shortly. Like all fuels, petro- or bio-, VW doesn't cover "misfueling" with bad quality fuel. If a tank of bad petrodiesel damages your injection pump, the retailer, not VW pays for the repair. So using biodiesel really isn't an issue as far as that is concerned.
Premptively, let me make this very clear so we don't need to have the same discussion everytime biodiesel comes up.
First, biodiesel has a positive energy balance, to the tune of about 3.2 units out for every unit you put in. http://www.nrel.gov/docs/legosti/fy98/24089.pdf
Second, biodiesel is 78% carbon neutral with regard to greenhouse gas emissions (see previous pdf). That is because the majority of the carbon emitted when you burn a gallon of biodiesel was captured from the atmosphere when you grew the plant to make the vegetable oil. However, the methanol used to make the biodiesel (fatty acid methyl ester) is made from natural gas, at least in the US. You could make 100% renewable ethyl ester biodiesel from ethanol, or make methanol from landfill recovery biogas, but we don't currently.
Third, soy and corn oil are crummy crops to make biodiesel from. But that's where the lobbying money is right now. Other plants have much higher yields.
http://journeytoforever.org/biodiesel_yield.html
Forth, no, it isn't a question of "food or fuel"? We can do both! Whenever you hear that argument ask yourself whether the person is well meaning but misinformed, or as been happening recently, is part of astroturf campaign to preserve the status quo of the petroleum economy.
Want to try making some biodiesel yourself?
http://www.biodieselcommunity.org/howitsmade/
Already making biodiesel and want to show it off?
http://www.cafepress.com/RenewableWear
Just because no one the submitter knows uses biodiesel doesn't make biodiesel an "experimental" fuel.
This so-called news from Rolland is nothing new.
In fact, I have a BS and MS in Food Science from Cornell.
http://www.foodsci.cornell.edu/
Nor am I the only one. There are over 40 Food Science programs in the US. This is a non-story.
http://www.ift.org/cms/?pid=1000624
Just be aware that Pimentel releases this "finding" every other summer, Looking at the dates below, he's a month ahead of schedule this year.
P imentel-ethanol.html
P imentel-ethanol.html
l .toocostly.ssl.html
o nneNatlLabEthanolStudy.pdf
d =UBB14&Number=946804&Searchpage=1&Main=941398&Word s=%2Bethanol+%2Bmoney+DrStink&topic=&Search=true#P ost946804
http://www.news.cornell.edu/Chronicle/01/8.23.01/
http://www.news.cornell.edu/Chronicle/03/8.14.03/
http://www.news.cornell.edu/stories/July05/ethano
I can't speak to this newest report, but Pimental's work has been repeatedly critiqued, and one of the main compliants it that he uses out of date numbers for yield and conversion efficiency:
http://www.mda.state.mn.us/ethanol/balance.html
http://www.usda.gov/oce/oepnu/aer-814.pdf
http://journeytoforever.org/ethanol_rooster.html
http://www.ncga.com/public_policy/PDF/03_28_05Arg
http://www.ethanol-gec.org/corn_eth.htm
All that having been said, Pimental is right that soy and corn alone cannot replace our petroleum addiction. You can read more about this in the archives at TDIclub.com.
http://forums.tdiclub.com/showflat.php?Cat=0&Boar
can these robots play hockey?
Ethanol is *also* energy positive. Pimental's old calculations have been thoroughly debunked.
Corn based ethanol doesn't return quite as much energy as BD, but it still has a positive energy balance on the order of 1.67 units out for every unit in. Compare this to 3.2 units out for every unit in for biodiesel.
Then compare both of those to .80 for gasoline and .85 for diesel and biofuels clearly win the energy balance arguement.
More reading:
http://www.mda.state.mn.us/ethanol/balance.html
http://www.usda.gov/oce/oepnu/aer-814.pdf
"Another promising candidate is bio-diesel; on the plus side you can easily convert a diesel engine today - on the down side harvesting and processing the crops "costs" more energy (according to some studies) than you're getting in the biodiesel from the solar energy the crops grew on."
You've got the right idea but you've got a couple of details wrong.
a)NO Conversion is needed to run Biodiesel in a modern diesel. You're confusing BD with WVO, which does require conversion.
b)I know of no studies that claim biodiesel has a negative energy balance. You're thinking of ethanol, not biodiesel, and even then those calculations have been refuted with newer data.
"Please note that we're NOT talking about corn ethanol, which a highly subsidized and environmentally contentious product due to high energy costs of growing and harvesting corn."
m l
Actually, even corn-ethanol has a positive energy balance these days. Much of the confusion dates back to some old calculation's by Pimental at Cornell that found corn-ethanol had a negative energy balance when in fact more recent USDA numbers show that corn-ethanol produces 67% more energy that it takes to produce it.
Still, biodiesel blows ethanol out of the water in terms of energy balance. And that's making B100 from soy. Imagine the energy return if we made it from dual use crops like mustard or better yet from algae.
Algae source biodiesel grown on 15,000 sq. miles could completely displace petroleum transporation fuels in the US. Don't believe me? Read Mike Briggs' analysis for yourself:
http://www.unh.edu/p2/biodiesel/article_alge.ht
Driving a modern VW or MB diesel whether or not you ever plan to use a single drop of domestically produced biodiesel is a good place to start.
My 2003 Jetta TDI has 40862 miles on it and I've used 832.7 gallons of diesel (and 56.9 gallons of biodiesel) thus far. For those of you keeping score at home, that's about 45.93 mpg over the life of the car. Not too shabby.
Why wait 15-20 years for hydrogen when we can start reducing our dependence on foreign oil NOW?
Here is a nice link to a thoughtful discussion of soem of these issues.
r ti cles/johnson.html
s ht ml
http://www.nature.com/nature/debates/e-access/A
Project Euclid is a just one initiative to make math and statistics journals affordable.
http://projecteuclid.org/Dienst/UI/1.0/Home
Finally, Universities themselves can stand up against rising subscription fees. Cornell did, and told Elsevier to piss off.
http://www.infotoday.com/newsbreaks/nb031117-1.
" Biodiesel doesn't have anything to do with cutting down emissions. You're still burning hydrocarbons."
Actually, regardless of whether or not Darryl Hannah is a moron, you are wrong.
Because the carbon in the vegetable oil used to make biodiesel is already part of the carbon cycle (opposed to having been sequestered underground for millions of years), biodiesel does not, for the most part, contribute to a NET INCREASE in carbon dioxide.
In fact, research by the US DOE suggests that biodiesel use cuts net CO2 emissions by 78%.
http://www.ott.doe.gov/pdfs/biodieselfuel.pdf
The reason it isn't 100% is because the methanol reacted with the veggie oil to make the methyl ester comes from petroleum in the US. You can make ethyl ester biodiesel using non-petrochemical based ethanol, but the process control is less forgiving.
"But it would have to remain a separate product becauase petroleum oil and vegatable oils aren't miscible. "
Except that biodiesel *isn't* vegetable oil. It is a fatty acid methyl ester (FAME) *made* from vegetable oil. Not the same thing.
I 'splash-blend' biodiesel and petro diesel in my TDI all the time. Pour 5 gallons of B100 into the tank and then top off the rest of the tank with petrodiesel. This is standard practice in the BD community.
And besides, then I get to wear one of these neato t-shirts.
http://www.cafeshops.com/renewablewear/338613
You are correct that diesel contains more stored energy than gasoline per gallon but I don't think it is anyway near 2 times as much.
I don't have the numbers handy but I seem to recall it is about 130,000 BTUs vs. 115,000 BTUs.
It's called the TDI. VW already sells it. ;)
Seriously, I like that SAE is encouraging this sort of blue-sky stuff, but sometimes I wonder if in general these sort of events encourage average Joe to assume high mileage vehicles and renewables are 10 or more years away.
High mileage vehicles are here *now*. Renewables are here *now*. Let's use 'em.
On my last 2 tanks, I drove 1156 miles on 13.24 gallons of diesel blended on the fly with 10 gallons of biodiesel. That's 50 mpg or 87 miles per petrogallon. Not too shabby.
It may not be 1700mpg, but it is a step in the right direction and it's here now. Help spread the word.
www.tdiclub.com
www.biodieselnow.com
www.cafepress.com/renewablewear
" I'm sorry if my vehicle of choice isn't the most environmentally-minded design, but you forget how many other vehicles that are equally as bad for the environment are often left out of these arguments-ANY MUSCLE CARS, Mustang, Camaro, Corvette...All of these cars guzzle gas just as much as any SUV, and some are worse, in fact. "
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Bzzt. Thank you for playing.
2004 'Vette gets 19/28 mpg with the manual. (Anyone buying an auto 'vette should be beaten.)
http://www.edmunds.com/new/2004/chevrolet/corve
2004 Explorer gets 15/20 mpg.
http://www.edmunds.com/new/2004/ford/explorer/1
Look. If you *need* an SUV, fine. But the muscle car issue is a weak rationalization at best and comes across as a disingenous red herring for the more cynically minded.
Somehow I suspect a Passat TDI would haul all your stuff and get *twice* the mileage of your Explorer, but hey, only chicks drive veedubs, right?
Actually, maybe you could learn a little humility because Grade D is in fact a legitimate grade of beef.
The Prime/Choice/Select/etc grades you were refering to is a function of both maturity and marbling. The letter grades refer to the maturity of the carcass. Specifically, Prime/Choice/Select/Standard are always Grade A or B. However, Commercial/Utility/Cutter and Canner can be of Grades C through E.
Thus, if I'm buying commercial grade beef as retail estabilishment, I sure want to know if it is Grade C, D, or E to make sure I'm not getting ripped off by the supplier.
Don't believe me? http://www.ianr.unl.edu/pubs/beef/rp357.htm
Ummm. No. OSX is really NeXTstep 6.1 with a macintosh application environment thrown in. NeXTstep is a proven stable OS that predates Linux by at least 3 years. Furthermore, the core foundation of OSX, known as Darwin is also open source.