The Bennett mechanism is a highly overconstrained "mobile spatial four-bar linkage." (Yeah, yeah, the Bennett mechanism is 100 year old prior art, but I am saying some new discovery yet to be made of a linkage.) What makes something a Bennett mechanism is a precise relationship between the link lengths and the link "twist angles." So a Bennett mechanism is not the materials nor whether you use roller or journal bearings nor the thickness and shape of the links. A Bennett mechanism is essentially a mathematical relationship.
That the Bennett mechanism is mobile instead of a rigid "tensegrity structure" has to do with some deep mathematical relationships that may yet yield to a simple proof.
I dispute your assertion that the auto companies "grade themselves" on gas mileage.
As far as it is known, every model of every car maker has to go to Ann Arbor for the original "EPA" drive cycle -- this is for smog control certification, and you extract the EPA City numbers from that, and I think the old "Highway" test is included, both tests used for CAFE regs.
EPA has a new or extended cycle including the high speed highway driving used for the current window sticker. For most cars, they get the "new" sticker numbers be a formula applied to CAFE, but for selected cars, they or the car makers run a full test on them.
With respect to cheating rather than optimizing for or "teaching to the test", EPA relies on the car makers to conduct coast-down or other tests to come up with the drag coefficients to put into the chassis dyno in Ann Arbor. Folks should look up the Test Car List Data (Google for it) for the raw EPA results along with the drag coefficients for the different car models. I am thinking that if we "crowd source" that task, there may be "interesting" findings.
This business of EPA numbers and whether they can be achieved or not achieved generates such emotions.
This is Slashdot. We are geeks. We embrace the scientific method, which includes experimental control.
One knock on the EPA is that they "do a lab test that is never reproduced out on the highway."
What I am saying or suggesting is that driving 55 MPH on a calm wind day without the A/C is a good proxy for the EPA Highway test. I am not saying you have to drive 55 or should drive 55, it is just that there are some stretches of road with a 55 MPH limit that would be a good place to test a car.
So Question 1, what gas mileage do you get driving at 55 MPH on the highway under calm wind conditions, and how does it compare with the EPA test. It's called "experimental control." That is, you first try to see if a car gets anywhere near the EPA gas mileage when driven under as close to EPA conditions as is reasonable for someone without a chassis dyno and an exhaust gas analyser like they have in Ann Arbor, MI at the EPA testing station. If the C-Max and Fusion Hybrid are not getting their EPA numbers, and I am talking the raw numbers and not the "adjusted" numbers on the window sticker, then there is a case to be made that Ford is cheating.
Then Question 2, what gas mileage do you get, say, driving 65 MPH as in the Consumer Reports test? If the C-Max and Fusion do OK at 55 MPH but are not so thrifty at 65 MPH, maybe Ford isn't cheating, but they have optimized those cars for 55 MPH when most people drive 65 MPH (or faster) on the highway. This is an important distinction to us geeks grounded in Experimental Control and the Scientific Method.
So them my Question 3, why doesn't Consumer Reports conduct a road test that best replicates EPA conditions before they start knocking cars for not "living up to the EPA numbers." I don't care about the song, "Pull my license, and all that jive, I . . . can't . . . drive . . . 55!" For cryin' out loud, doesn't Consumer Reports believe in Experimental Control? Report a highway number at a constant 55 and then report a highway number at a constant 65.
Question 4, so why did Consumer Reports change their "highway" road test mid stream? I think they sped up their highway road test to be more consistent with the way their readers drive. Fine. But then you have an apples and oranges comparison between a car built now and maybe a car you owned 30 years ago. Suppose I want to know how a Prius stacks up against the low-tech non-hybrid 1.6 litre 5-speed manual-shift Nova/Corolla I had purchased back in 1986? Can't compare by going through old stacks of Consumer Reports.
A lot of people are singing to tune to "I can't drive . . . fifty-five!"
So one level of complaint is that "I get nowhere near the EPA mileage because who drives like that" apart from hyper-miling geeks, old persons, and dudes with a passive-aggressive anti-social attitude. I can see the point, however. Suppose I drive (legally) at 70 MPH and the car is optimized for 50 MPH, how do I read the EPA sticker to find a car that gets OK mileage for the way I drive?
The next level of complaint is that "I am a hypermiling geek, and even I don't get the EPA mileage."
So the question is, is the EPA test even accurate on its own terms?
My limited experience with a Taurus and with a Camry and using a Scan Gauge, if you drive about 10 miles on a 70-deg day without the AC at an average speed of 20 MPH in traffic, you will get better than the derated window sticker and will be within 5% of the "raw EPA numbers." If you drive a constant 55 MPH on a calm wind day, you will get the raw EPA Highway numbers.
The Taurus started to not get the EPA numbers. It turned out to have dragging brakes from rusted caliper pins.
I don't doubt there is cheating, however. I look over the EPA "Test Car List Data" and have seen some fishy drag or coast-down time numbers.
But are people experiencing that if you drive like Granny, some cars get the EPA and o/thers don't? Are there variations between cars of the same model and year, that some engines are manufactured "tight" with much friction and other cars have a natural aptitude for MPG?
Actually we didn't have a clue has to who the Ferengi "were supposed to be" apart from Lt Cmdr Data calling them "Yankee traders."
And then actor Armin Shimerman came along with his scenery-chewing rendition of Quark on DS-9, portraying a Ferengi as an angst-driven discriminated-against entrepreneur, evoking memories of a character in, dunno, Shakespeare's "Merchant of Venice" ("does not a Jew bleed . ..").
And then the Ferengi became an ethnic stereotype -- superintelligent for having a four-lobed brain, but adhering to an ethical system known as the "Laws of Acquisition" that are studied with an almost religious devotion, well, you kind of get the idea.
Look, just because Jewish people were involved in the creation of Star Trek doesn't mean Star Trek doesn't reinforce certain stereotypes, maybe by Mr. Shimerman having a blast with his campy character.
Unless someone tells me differently, the West, Texas accident was a BLEV -- boiling liquid expanding vapor -- accident.
When you rupture a vessel containing a liquid under pressure, the liquid "flashes" into vapor driving an explosion, the power of which is enhanced by the conflagration of the ammonia when it meets air.
BLEV's were the mechanism behind boiler explosions involving incombustible H2O back in the day of steam locomotives (and in this day with accidents with antique steam tractors). You can also get BLEVs with propane or other hydrocarbon liquids. There was some recent controversy about Google Page Rank, where a search for some campground in Spain turns up a horrific disaster where a BLEV from a badly maintained tanker truck taking a shortcut over back roads to avoid tolls blew up.
I fully expect someone on the TV news to make such a mistake, but to conflate West, Texas with the explosive properties of the ANFO mix, yes, some heads need to be removed from back sides, and some persons of limited intellect need to stop procreating. Is there anyway to remove this thread from Slashdot so we don't look like people who should be prevented from reproducing?
Forget that, will this be reinventing, dunno, "MFC.NET", where software is effortlessly implemented, tested, and documented using a mix of object classes, C++ templates, custom extensions to C++ that break portability, "wizard" (i.e. obscure template) generated code, a virtual machine, and calls between "managed code" on the virtual machine and native code that break security and prompt stern security scoldings when your code is on a virtual drive or "network share"?
No, my understanding of evolution is limited to attending a public lecture of the late Stephen Jay Gould and reading most of his popular-literature-for-the-layman books on the subject. There are things observed directly, such as the moths in smoggy London or the swallows in the highway overpass, and there are many things observed indirectly, such as the cladistic relationships in the fossil record or the Woese genetic distances.
Gould discusses many of the gaps in scientific understanding of evolution, and maybe I haven't kept up on the latest science on the filling in of those gaps. But I was suggesting, that parts of evolution are "magic" in these sense of Arthur C Clarke, not magic in the sense of violating any natural laws, but magic in the sense that there are many hypothesized mechanisms for which scientific research is still filling in the details.
At your suggestion, I Googled "nylonase", and as the name suggests, this is an enzyme that is inferred to have entered the gene pool of bacteria through a mutation that allows these bacteria to process a man-made substance. As another response to my post suggested, there is a big gap between what happens in bacteria with speciation in sexual-reproducing multi-celluar eucaryotic species.
And something for which there is compelling evidence can be discussed in reasoned, even-tempered prose, without ad-hominen attacks on the knowledge of someone one barely knows, and without the words "zero" and "absurd" in shouting caps.
Using the swallows to dis' religion is merely helping the anti-evolutionists say "I told you so."
Are the short-winged swallows unable to mate with other swallow in their parent population?
There is no dispute that traits are inherited and that of the traits in the gene pool of an organism, certain traits can be selected, either through breeding or through environmental selection pressure such as road kill of swallows, soot on trees with moths, or superbugs emerging with antibiotic resistance.
Has anyone, however, observed this selection effect going on for a long enough time for the emergence of new species?
Has anyone seen mutations arise that weren't in the gene pool of an organism and seen the mutated form "take over" a population because the mutation conferred a survival advantage, in other words, a Hopeful Monster in the lingo of evolutionary biology?
So in the Arthur C Clarke sense of any tech beyond current knowledge takes on the appearance of magic, evolution is and remains magic. There are a variety of hypothesized ways to generate entirely new species, but they have not been observed directly.
The videos that I find most informative of both the teaching and learning experience are 1) John Cleese in The Meaning of Life as the English Public School instructor who manages to make "the facts of life" a complete bore, 2) John Cleese in Life of Brian in the stoning scene, 3) Ben Stein and the ensemble cast in the "Bueller . . . Bueller" scene, and 4) Father Guido Sarducii's "5 Minute University."
The most common kind of non-conservative system has some kind of friction in it.
I suppose you could treat friction as a conservative system with a gadzillion particles for each of the molecules. But generally speaking, there are mechanisms that transfer energy out of the system into "something else" (mainly heat). And I think I came across one old paper trying for a "variational" method on such systems, but mostly folks turn the Lagrangian variational problem into the Euler-Lagrange dif eq, interpret the terms as "generalized forces", and add friction forces. But then you incur the problems of numerical solution of differential equations whereas if you could keep things at the variational level, you can get better solutions because you can enforce the conservation of energy, momentum.
OK Dr. Wizeguy Physicist, I can "buy into" energy being conserved -- the sum of kinetic and potential energy stays the same unless energy is transfered into or out of the system.
But tell me, why for this quantity called "the action", the difference between kinetic and potential energy, is the integrated value of which between fixed starting points in space in time minimized?
And why is it this "principle of least action" can only be formulated for an energy conservative system, which means that you have to formulate the solution to that variational problem as a differential equation and add the energy loss terms as fudge factors on that differential equation?
I asked this question of one colleague with an ongoing DOE grant in Controlled Nuclear Fusion and another colleague whose degree is in Physics and gotten only shrugs. I asked this of a Mechanical Engineering grad student who is from Russia and he started saying about a "Legendre transformation" followed by a discussion of Feynman Diagrams where he lost me.
Does anyone outside of Russia understand any of this?
Manhattan, there's your problem right there. Maybe Kramer from "Seinfeld" got ahold of it and wanted the thrill of driving it with the charge gauge on "E."
My gripe isn't so much the how-much-petroleum to generate a gallon of ethanol or farming-for-fuel-is-ruining-the-land.
Suppose the "farm problem" is one of bumper crops and overproduction and farmers driven into debt slavery. So you take some of the "excess" corn production, turn it into ethanol to stretch the supply of gasoline, make some animal feed as a byproduct, and support farm prices. I know the Libertarians will be all over me like a pile of bricks, but there are all kinds of social, political, and cultural reasons why we don't have "efficient" markets in the ag sector.
So we have this drought, blame it on Global Warming, blame it on Natural Cycles, blame it on Divine wrath for our social tolerance, but we have this drought and a reduced supply of corn.
Do you suppose, we could make some minor exceptions, some minor exemptions to the mandates, so more of the corn goes into (largely animal feed, but sorry vegans, I like my meat) the food supply and a little less of it goes into the tank?
I mean, one of the reasons for the ethanol thing is to level out market swings on the farmers, but with the ethanol mandates being sacred environmental writ, the folks at the EPA and the USDA and in Congress up to the President, that these folks are on such complete ideological auto-pilot about bio-fuels that there cannot be a mild adjustment to prevent one class of farmer (grain) being hated by another class of farmer (cattle, pigs, chickens) along with consumers?
But it seems everyone is "so Herbert" to borrow a Star Trek expression that there is no flexibility on the use of corn for fuel in a corn-short year?
Slashdot Mirror
The Bennett mechanism is a highly overconstrained "mobile spatial four-bar linkage." (Yeah, yeah, the Bennett mechanism is 100 year old prior art, but I am saying some new discovery yet to be made of a linkage.) What makes something a Bennett mechanism is a precise relationship between the link lengths and the link "twist angles." So a Bennett mechanism is not the materials nor whether you use roller or journal bearings nor the thickness and shape of the links. A Bennett mechanism is essentially a mathematical relationship.
That the Bennett mechanism is mobile instead of a rigid "tensegrity structure" has to do with some deep mathematical relationships that may yet yield to a simple proof.
The man doesn't have any pretensions that what he is doing isn't just a job and isn't anything more serious than entertainment.
As far as it is known, every model of every car maker has to go to Ann Arbor for the original "EPA" drive cycle -- this is for smog control certification, and you extract the EPA City numbers from that, and I think the old "Highway" test is included, both tests used for CAFE regs.
EPA has a new or extended cycle including the high speed highway driving used for the current window sticker. For most cars, they get the "new" sticker numbers be a formula applied to CAFE, but for selected cars, they or the car makers run a full test on them.
With respect to cheating rather than optimizing for or "teaching to the test", EPA relies on the car makers to conduct coast-down or other tests to come up with the drag coefficients to put into the chassis dyno in Ann Arbor. Folks should look up the Test Car List Data (Google for it) for the raw EPA results along with the drag coefficients for the different car models. I am thinking that if we "crowd source" that task, there may be "interesting" findings.
This is Slashdot. We are geeks. We embrace the scientific method, which includes experimental control.
One knock on the EPA is that they "do a lab test that is never reproduced out on the highway."
What I am saying or suggesting is that driving 55 MPH on a calm wind day without the A/C is a good proxy for the EPA Highway test. I am not saying you have to drive 55 or should drive 55, it is just that there are some stretches of road with a 55 MPH limit that would be a good place to test a car.
So Question 1, what gas mileage do you get driving at 55 MPH on the highway under calm wind conditions, and how does it compare with the EPA test. It's called "experimental control." That is, you first try to see if a car gets anywhere near the EPA gas mileage when driven under as close to EPA conditions as is reasonable for someone without a chassis dyno and an exhaust gas analyser like they have in Ann Arbor, MI at the EPA testing station. If the C-Max and Fusion Hybrid are not getting their EPA numbers, and I am talking the raw numbers and not the "adjusted" numbers on the window sticker, then there is a case to be made that Ford is cheating.
Then Question 2, what gas mileage do you get, say, driving 65 MPH as in the Consumer Reports test? If the C-Max and Fusion do OK at 55 MPH but are not so thrifty at 65 MPH, maybe Ford isn't cheating, but they have optimized those cars for 55 MPH when most people drive 65 MPH (or faster) on the highway. This is an important distinction to us geeks grounded in Experimental Control and the Scientific Method.
So them my Question 3, why doesn't Consumer Reports conduct a road test that best replicates EPA conditions before they start knocking cars for not "living up to the EPA numbers." I don't care about the song, "Pull my license, and all that jive, I . . . can't . . . drive . . . 55!" For cryin' out loud, doesn't Consumer Reports believe in Experimental Control? Report a highway number at a constant 55 and then report a highway number at a constant 65.
Question 4, so why did Consumer Reports change their "highway" road test mid stream? I think they sped up their highway road test to be more consistent with the way their readers drive. Fine. But then you have an apples and oranges comparison between a car built now and maybe a car you owned 30 years ago. Suppose I want to know how a Prius stacks up against the low-tech non-hybrid 1.6 litre 5-speed manual-shift Nova/Corolla I had purchased back in 1986? Can't compare by going through old stacks of Consumer Reports.
So one level of complaint is that "I get nowhere near the EPA mileage because who drives like that" apart from hyper-miling geeks, old persons, and dudes with a passive-aggressive anti-social attitude. I can see the point, however. Suppose I drive (legally) at 70 MPH and the car is optimized for 50 MPH, how do I read the EPA sticker to find a car that gets OK mileage for the way I drive?
The next level of complaint is that "I am a hypermiling geek, and even I don't get the EPA mileage."
So the question is, is the EPA test even accurate on its own terms?
My limited experience with a Taurus and with a Camry and using a Scan Gauge, if you drive about 10 miles on a 70-deg day without the AC at an average speed of 20 MPH in traffic, you will get better than the derated window sticker and will be within 5% of the "raw EPA numbers." If you drive a constant 55 MPH on a calm wind day, you will get the raw EPA Highway numbers.
The Taurus started to not get the EPA numbers. It turned out to have dragging brakes from rusted caliper pins.
I don't doubt there is cheating, however. I look over the EPA "Test Car List Data" and have seen some fishy drag or coast-down time numbers.
But are people experiencing that if you drive like Granny, some cars get the EPA and o/thers don't? Are there variations between cars of the same model and year, that some engines are manufactured "tight" with much friction and other cars have a natural aptitude for MPG?
And then actor Armin Shimerman came along with his scenery-chewing rendition of Quark on DS-9, portraying a Ferengi as an angst-driven discriminated-against entrepreneur, evoking memories of a character in, dunno, Shakespeare's "Merchant of Venice" ("does not a Jew bleed . . .").
And then the Ferengi became an ethnic stereotype -- superintelligent for having a four-lobed brain, but adhering to an ethical system known as the "Laws of Acquisition" that are studied with an almost religious devotion, well, you kind of get the idea.
Look, just because Jewish people were involved in the creation of Star Trek doesn't mean Star Trek doesn't reinforce certain stereotypes, maybe by Mr. Shimerman having a blast with his campy character.
When you rupture a vessel containing a liquid under pressure, the liquid "flashes" into vapor driving an explosion, the power of which is enhanced by the conflagration of the ammonia when it meets air.
BLEV's were the mechanism behind boiler explosions involving incombustible H2O back in the day of steam locomotives (and in this day with accidents with antique steam tractors). You can also get BLEVs with propane or other hydrocarbon liquids. There was some recent controversy about Google Page Rank, where a search for some campground in Spain turns up a horrific disaster where a BLEV from a badly maintained tanker truck taking a shortcut over back roads to avoid tolls blew up.
I fully expect someone on the TV news to make such a mistake, but to conflate West, Texas with the explosive properties of the ANFO mix, yes, some heads need to be removed from back sides, and some persons of limited intellect need to stop procreating. Is there anyway to remove this thread from Slashdot so we don't look like people who should be prevented from reproducing?
So are Kilby and Noyce the two competing gods in the Zorastrian religious system?
Yes, then they would be "SMD."
Forget that, will this be reinventing, dunno, "MFC .NET", where software is effortlessly implemented, tested, and documented using a mix of object classes, C++ templates, custom extensions to C++ that break portability, "wizard" (i.e. obscure template) generated code, a virtual machine, and calls between "managed code" on the virtual machine and native code that break security and prompt stern security scoldings when your code is on a virtual drive or "network share"?
What if the purported caches of "evil spells" proves to be false?
Some have an "in" and other have an "out."
No, my understanding of evolution is limited to attending a public lecture of the late Stephen Jay Gould and reading most of his popular-literature-for-the-layman books on the subject. There are things observed directly, such as the moths in smoggy London or the swallows in the highway overpass, and there are many things observed indirectly, such as the cladistic relationships in the fossil record or the Woese genetic distances. Gould discusses many of the gaps in scientific understanding of evolution, and maybe I haven't kept up on the latest science on the filling in of those gaps. But I was suggesting, that parts of evolution are "magic" in these sense of Arthur C Clarke, not magic in the sense of violating any natural laws, but magic in the sense that there are many hypothesized mechanisms for which scientific research is still filling in the details. At your suggestion, I Googled "nylonase", and as the name suggests, this is an enzyme that is inferred to have entered the gene pool of bacteria through a mutation that allows these bacteria to process a man-made substance. As another response to my post suggested, there is a big gap between what happens in bacteria with speciation in sexual-reproducing multi-celluar eucaryotic species. And something for which there is compelling evidence can be discussed in reasoned, even-tempered prose, without ad-hominen attacks on the knowledge of someone one barely knows, and without the words "zero" and "absurd" in shouting caps.
Are the short-winged swallows unable to mate with other swallow in their parent population?
There is no dispute that traits are inherited and that of the traits in the gene pool of an organism, certain traits can be selected, either through breeding or through environmental selection pressure such as road kill of swallows, soot on trees with moths, or superbugs emerging with antibiotic resistance.
Has anyone, however, observed this selection effect going on for a long enough time for the emergence of new species?
Has anyone seen mutations arise that weren't in the gene pool of an organism and seen the mutated form "take over" a population because the mutation conferred a survival advantage, in other words, a Hopeful Monster in the lingo of evolutionary biology?
So in the Arthur C Clarke sense of any tech beyond current knowledge takes on the appearance of magic, evolution is and remains magic. There are a variety of hypothesized ways to generate entirely new species, but they have not been observed directly.
Maybe you were quoting Latter-Day Saints Church founder Joseph Smith's translation instead of the King James version?
The videos that I find most informative of both the teaching and learning experience are 1) John Cleese in The Meaning of Life as the English Public School instructor who manages to make "the facts of life" a complete bore, 2) John Cleese in Life of Brian in the stoning scene, 3) Ben Stein and the ensemble cast in the "Bueller . . . Bueller" scene, and 4) Father Guido Sarducii's "5 Minute University."
I suppose you could treat friction as a conservative system with a gadzillion particles for each of the molecules. But generally speaking, there are mechanisms that transfer energy out of the system into "something else" (mainly heat). And I think I came across one old paper trying for a "variational" method on such systems, but mostly folks turn the Lagrangian variational problem into the Euler-Lagrange dif eq, interpret the terms as "generalized forces", and add friction forces. But then you incur the problems of numerical solution of differential equations whereas if you could keep things at the variational level, you can get better solutions because you can enforce the conservation of energy, momentum.
But tell me, why for this quantity called "the action", the difference between kinetic and potential energy, is the integrated value of which between fixed starting points in space in time minimized?
And why is it this "principle of least action" can only be formulated for an energy conservative system, which means that you have to formulate the solution to that variational problem as a differential equation and add the energy loss terms as fudge factors on that differential equation?
I asked this question of one colleague with an ongoing DOE grant in Controlled Nuclear Fusion and another colleague whose degree is in Physics and gotten only shrugs. I asked this of a Mechanical Engineering grad student who is from Russia and he started saying about a "Legendre transformation" followed by a discussion of Feynman Diagrams where he lost me.
Does anyone outside of Russia understand any of this?
Manhattan, there's your problem right there. Maybe Kramer from "Seinfeld" got ahold of it and wanted the thrill of driving it with the charge gauge on "E."
Suppose the "farm problem" is one of bumper crops and overproduction and farmers driven into debt slavery. So you take some of the "excess" corn production, turn it into ethanol to stretch the supply of gasoline, make some animal feed as a byproduct, and support farm prices. I know the Libertarians will be all over me like a pile of bricks, but there are all kinds of social, political, and cultural reasons why we don't have "efficient" markets in the ag sector.
So we have this drought, blame it on Global Warming, blame it on Natural Cycles, blame it on Divine wrath for our social tolerance, but we have this drought and a reduced supply of corn.
Do you suppose, we could make some minor exceptions, some minor exemptions to the mandates, so more of the corn goes into (largely animal feed, but sorry vegans, I like my meat) the food supply and a little less of it goes into the tank?
I mean, one of the reasons for the ethanol thing is to level out market swings on the farmers, but with the ethanol mandates being sacred environmental writ, the folks at the EPA and the USDA and in Congress up to the President, that these folks are on such complete ideological auto-pilot about bio-fuels that there cannot be a mild adjustment to prevent one class of farmer (grain) being hated by another class of farmer (cattle, pigs, chickens) along with consumers?
But it seems everyone is "so Herbert" to borrow a Star Trek expression that there is no flexibility on the use of corn for fuel in a corn-short year?
So is it Rapiscan as in "add" or Rapiscan as in "ape"?
No, it was the head guy in Egypt.
Can't find the best link, but Iran was caught with a Photoshop enhanced picture of a multiple rocket launch where they dubbed in a fourth rocket.
The wags had a field day with that, with one pranked photo with Jar Jar Binks added making it back on to an Iranian news site.
Didn't the Onion do one where the rockets were criss-crossing the sky in all directions?
Is this better?
Gee, don't confuse the actor and the character.