Why should we bother trying?
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re: Why should we bother trying?
Dear Grimer,
Your analysis is quite interesting and complete, and I hope to find the appropriated mechanism needed for your above concept.
It should be not far from these motions, see this old post here:
http://www.besslerwheel.com/forum/viewt ... b84b#76360
In any case I think there is a very basic solution as shown in the animation below.
I apologize for the 'Caesar courtesy': I don't remember where I found this, and I was unable to recover the name of the author. Many thanks to him.
With the displayed concept, there is no additional mechanism (excepted the reduction speed gear linkage).
The weights are exchanged between the both wheels only by the gravity.
The unbalance is just obtained by the unbalanced location of the exchange (1:30 - 7:30 diameter)
edited:
the first flickering animation has been replaced.
And may be, some springs are needed at 7:30 (at 1:30 the CF should be sufficient)
Your analysis is quite interesting and complete, and I hope to find the appropriated mechanism needed for your above concept.
It should be not far from these motions, see this old post here:
http://www.besslerwheel.com/forum/viewt ... b84b#76360
In any case I think there is a very basic solution as shown in the animation below.
I apologize for the 'Caesar courtesy': I don't remember where I found this, and I was unable to recover the name of the author. Many thanks to him.
With the displayed concept, there is no additional mechanism (excepted the reduction speed gear linkage).
The weights are exchanged between the both wheels only by the gravity.
The unbalance is just obtained by the unbalanced location of the exchange (1:30 - 7:30 diameter)
edited:
the first flickering animation has been replaced.
And may be, some springs are needed at 7:30 (at 1:30 the CF should be sufficient)
I cannot imagine why nobody though on this before, including myself? It is so simple!...
re: Why should we bother trying?
I can now see that the previous analysis ...
http://www.besslerwheel.com/forum/viewt ... 1294#81294
... works because the Keenie Wheel is generating a fourth derivative of position with respect to time.
Using Newtonian notation (because it's easier to display with the forum fonts available).
.... x'(t) is first derivative of position, velocity (v)
.... x''(t) is second derivative of position, acceleration (a)
.... x'''(t) is third derivative of position, jerk (j)
.... x''''(t) is fourth derivative of position ..???... (?)
If the fourth derivative has a name I've never hear of it. Perhaps that's why no one has considered its use for a gravity mill. I'll give it the temporary name of (rend) until someone discovers an established name.
It seems to be a general rule in hierarchical systems that control is exercised two stages removed. A commissioned officer exercises control over the ranks through a non-commissioned officer. A factory manager exercises control over the workforce through a foreman, and so on.
An interesting example of jerk exercising control over velocity is given by the Desktop devil.
http://www.bbc.co.uk/bbcone/wallaceandg ... top-devil/
Now the action of the Keenie wheel involves the difference between a clockwise and a counter-clockwise jerk. In other words it generates the differential of jerk with respect to time, j'(t).
It seems that it is this rending action which is responsible for the generation of energy from the effectively asymmetric gravity wind.
But as Fletcher has correctly pointed out, theory has to be proved in practice before it can be accepted as correct.
There is evidence that Keenie did this but it is hearsay. Just as in the law, hearsay evidence in unacceptable, so also in science.
http://www.besslerwheel.com/forum/viewt ... 1294#81294
... works because the Keenie Wheel is generating a fourth derivative of position with respect to time.
Using Newtonian notation (because it's easier to display with the forum fonts available).
.... x'(t) is first derivative of position, velocity (v)
.... x''(t) is second derivative of position, acceleration (a)
.... x'''(t) is third derivative of position, jerk (j)
.... x''''(t) is fourth derivative of position ..???... (?)
If the fourth derivative has a name I've never hear of it. Perhaps that's why no one has considered its use for a gravity mill. I'll give it the temporary name of (rend) until someone discovers an established name.
It seems to be a general rule in hierarchical systems that control is exercised two stages removed. A commissioned officer exercises control over the ranks through a non-commissioned officer. A factory manager exercises control over the workforce through a foreman, and so on.
An interesting example of jerk exercising control over velocity is given by the Desktop devil.
http://www.bbc.co.uk/bbcone/wallaceandg ... top-devil/
Now the action of the Keenie wheel involves the difference between a clockwise and a counter-clockwise jerk. In other words it generates the differential of jerk with respect to time, j'(t).
It seems that it is this rending action which is responsible for the generation of energy from the effectively asymmetric gravity wind.
But as Fletcher has correctly pointed out, theory has to be proved in practice before it can be accepted as correct.
There is evidence that Keenie did this but it is hearsay. Just as in the law, hearsay evidence in unacceptable, so also in science.
Who is she that cometh forth as the morning rising, fair as the moon, bright as the sun, terribilis ut castrorum acies ordinata?
- aStillMoreGloriousDawn
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re: Why should we bother trying?
Thank you all for taking the time to comment. I'm glad there was a good variety of responses so far.
getterdone -- Yes, the riddle of Bessler is quite a compelling one.. worth investigating!
Andyb -- 280 prototypes is indeed impressive.
rasselas -- I'm glad you and Andyb are motivated by the pursuit of a cleaner, more responsible world.
rickydog -- I, too, have believed in the concept of PM since a young age(I prefer the term over-unity). For me, it was triggered by a specific event during my childhood. It seems faith has played a positive role in your life.. I'm happy for you.
path_finder -- I'm glad you stepped up to the plate and provided a lot of information worth debating. Thank you very much for taking the time to do so.
In your first point you state: "1. The first reason is the lesson of the past, mainly -the Bessler's wheels -the buzzsaw -Asa Jackson -the uncle ramp toy -Villard de Honnecourt -the 'flowerbowl' "
I'm not sure what you are trying to say the lesson is. Are you saying that you believe these individuals had actually created working devices? For me, the lesson is that PM has been pursued since the beginning of human consciousness, with all(perhaps nearly all) of its pursuers failing. Just because there is an ancient relic doesn’t mean it once worked. If people a 1000 years from now happen to find any of our builds from today, are they to assume that all or any of them had worked? And, just because a story has been perpetuated through out the ages doesn't mean it should have any credence. (I believe you, yourself, already suggested this viewpoint in one of your other posts, found here: http://www.besslerwheel.com/forum/viewt ... ight=bible
For example, the "uncle ramp toy" story was created by the supposed nephew, who said he saw the toy as a young child. He said that he hadn't realized what he had seen(Perpetual Motion) until he was an adult. As an adult, he questioned his cousins as the uncle had already passed away. The story says that all the cousins agreed remembering it, but they didn't know what happened to it.
The "power of suggestion" has been shown to have a profound effect. How are we to know that the cousins weren’t persuaded by the nephew’s over-zealous questioning? For example, there is a university professor here in America that uses a simple trick to illustrate this to his students on their first day of Psychology class. He tells them to come to the front of the class to receive a cup of milk. He says, “I added varying amounts of strawberry flavoring to each cup, and I would like you to rate how strong the strawberry flavor is in your cup.� On the table are the cups of milk, along with a syrup bottle with a picture of strawberries on it. Each student follows the assignment, with many stating that the milk has a very strong strawberry flavor. Afterwards, the professor informed them that not one of their drinks contained strawberry flavor. Many of them insist that he must be wrong. He then tells them that in fact, he had put chocolate in the milk! (This experiment was demonstrated on an American TV show titled “Dateline�, along with many other social experiments of the same nature.) Considering there isn’t a physical relic from the creator(like there is the last remaining wheel from Asa Jackson), and considering there isn’t even a sketch from the creator, this one just seems like a tall tale. The nephew may seem quite convincing, but there is a lot to be said about “eye witness accounts�. Here is a fantastic video of a well-known U.S. scientist giving his take on how personal testimony rates in the standard of scientific evidence. Focus on minutes 2:35 through 4:00. http://www.youtube.com/watch?v=92ARrdaUd3A “An Argument from Ignorance� is a great title for this occurrence.
The story of the “uncle’s ramp toy� is obviously the easiest one to pick on. I think it would be good if there was a skeptical debate for each of the other examples you brought up. Yes, I know they have been discussed through out the years on this forum, but I have hardly heard any viewpoints from the opposing side. Perhaps it would prove to be a more comprehensive analysis if they were all in one place, such as this thread.. dedicated to rhetorical, thorough discussion. I understand this would take a lot of time. This would also take a lot of space, which is why I won’t discuss the others in this post. Perhaps, there is another member that would do a better job of directing the debate in a more systematic way.
path_finder -- I notice today is the exact date you joined the forum 2 years ago. Happy anniversary! I am very appreciative that you decided to share your experiments and builds so that all members can have the opportunity to learn from your hard labor. When you say one of your builds “rotates several turns and then stops�.. was it self-acting or did you have to provide the initial push? Just curious…
MrTim -- I know what you mean about being rebellious. I consider myself somewhat of a “utopian idealist�. Some consider this a mental flaw. Others consider this a waste of time because the world is not a place that rewards idealism. “Funny, I’ve always believed that the world is what we make of it.�
pequaide -- I had to look up Willem Jacob ‘s Gravesande. On his wikipedia page, it says that due to the results of his most noted experiment, “Emilie du Chatelet subsequently corrected Newton’s formula E = mv to E = mv^2.� Why does it say she “corrected�. Is this a dumb question to ask? http://en.wikipedia.org/wiki/Willem_'s_Gravesande
I saw the thread you started in October of 2008 entitled “energy producing experiments“.. It’s going to be awhile before I can catch up to you!
-----
Regarding my comments on religion: When I was writing my initial post, I had no intention of bringing it up. I simply wanted to see if I could get some cold, hard facts. However, most of the questions that I had asked were in reference to personal “belief�. I guess I couldn’t help but illustrate the similarities.
I see many parallels between the two topics; the main one being that both sets of believers want the subject to be true. I think when people are in need, it is much easier to believe the happier ending.
Also, like God, PM hasn’t been proven. If a skeptic comes along and says “That isn’t true, because you have no proof�.. a believer would say “Well prove that it isn't true�. That’s the thing though; you can’t prove a negative. So like some who continue to search for God, some continue to search for PM.
greendoor -- I can’t agree with your first statement. I think there is a very clear difference between the two entities, and that there is a very good reason for the perpetual friction that has been occurring between them. I could never say it as eloquently as Anne Druyan, so I will let her do the talking: http://www.youtube.com/watch?v=yvVCpJCTM5w
There are many, specifically elite scientists, who don’t view science as simply a body of knowledge, but rather a way of thinking.. “a collaborative enterprise spanning the generations“. This video demonstrates it in a simple and pleasant way that I think anyone should be able appreciate. http://www.youtube.com/watch?v=9Cd36WJ79z4
I understand my statements may be upsetting to some, so if they would like to continue this specific topic, I think they should create another thread in the Off-Topic portion of the forum.
You are right, though. There are good and bad individuals in every group, as you pointed out in another message to me.
Grimer -- I’m really glad you posted your follow-up study so quickly. I will have to dedicate another post to it, as this one is getting to be extremely long and annoying(I’m sure). However, I think it is unfair to accuse Ralph of having a jaundiced view after he dedicated so much labor and time into it. This is, after all, a thread dedicated to skeptical reasoning.
I’m glad you mentioned the Buzz Saw, because Preston Stroud’s fantastic craftsmen skills which were illustrated on his videos are the reason I came here. He kept saying “My friends at Besslerwheel.com�. It seemed like a good place to check out!
Perhaps Ralph could give us more details. I’m sure the other newbies, like myself, would appreciate the learning experience.
Again, sorry for the long post. I want to touch on other topics, but wanted to get my personal opinions out of the way first.
Thanks.
getterdone -- Yes, the riddle of Bessler is quite a compelling one.. worth investigating!
Andyb -- 280 prototypes is indeed impressive.
rasselas -- I'm glad you and Andyb are motivated by the pursuit of a cleaner, more responsible world.
rickydog -- I, too, have believed in the concept of PM since a young age(I prefer the term over-unity). For me, it was triggered by a specific event during my childhood. It seems faith has played a positive role in your life.. I'm happy for you.
path_finder -- I'm glad you stepped up to the plate and provided a lot of information worth debating. Thank you very much for taking the time to do so.
In your first point you state: "1. The first reason is the lesson of the past, mainly -the Bessler's wheels -the buzzsaw -Asa Jackson -the uncle ramp toy -Villard de Honnecourt -the 'flowerbowl' "
I'm not sure what you are trying to say the lesson is. Are you saying that you believe these individuals had actually created working devices? For me, the lesson is that PM has been pursued since the beginning of human consciousness, with all(perhaps nearly all) of its pursuers failing. Just because there is an ancient relic doesn’t mean it once worked. If people a 1000 years from now happen to find any of our builds from today, are they to assume that all or any of them had worked? And, just because a story has been perpetuated through out the ages doesn't mean it should have any credence. (I believe you, yourself, already suggested this viewpoint in one of your other posts, found here: http://www.besslerwheel.com/forum/viewt ... ight=bible
For example, the "uncle ramp toy" story was created by the supposed nephew, who said he saw the toy as a young child. He said that he hadn't realized what he had seen(Perpetual Motion) until he was an adult. As an adult, he questioned his cousins as the uncle had already passed away. The story says that all the cousins agreed remembering it, but they didn't know what happened to it.
The "power of suggestion" has been shown to have a profound effect. How are we to know that the cousins weren’t persuaded by the nephew’s over-zealous questioning? For example, there is a university professor here in America that uses a simple trick to illustrate this to his students on their first day of Psychology class. He tells them to come to the front of the class to receive a cup of milk. He says, “I added varying amounts of strawberry flavoring to each cup, and I would like you to rate how strong the strawberry flavor is in your cup.� On the table are the cups of milk, along with a syrup bottle with a picture of strawberries on it. Each student follows the assignment, with many stating that the milk has a very strong strawberry flavor. Afterwards, the professor informed them that not one of their drinks contained strawberry flavor. Many of them insist that he must be wrong. He then tells them that in fact, he had put chocolate in the milk! (This experiment was demonstrated on an American TV show titled “Dateline�, along with many other social experiments of the same nature.) Considering there isn’t a physical relic from the creator(like there is the last remaining wheel from Asa Jackson), and considering there isn’t even a sketch from the creator, this one just seems like a tall tale. The nephew may seem quite convincing, but there is a lot to be said about “eye witness accounts�. Here is a fantastic video of a well-known U.S. scientist giving his take on how personal testimony rates in the standard of scientific evidence. Focus on minutes 2:35 through 4:00. http://www.youtube.com/watch?v=92ARrdaUd3A “An Argument from Ignorance� is a great title for this occurrence.
The story of the “uncle’s ramp toy� is obviously the easiest one to pick on. I think it would be good if there was a skeptical debate for each of the other examples you brought up. Yes, I know they have been discussed through out the years on this forum, but I have hardly heard any viewpoints from the opposing side. Perhaps it would prove to be a more comprehensive analysis if they were all in one place, such as this thread.. dedicated to rhetorical, thorough discussion. I understand this would take a lot of time. This would also take a lot of space, which is why I won’t discuss the others in this post. Perhaps, there is another member that would do a better job of directing the debate in a more systematic way.
path_finder -- I notice today is the exact date you joined the forum 2 years ago. Happy anniversary! I am very appreciative that you decided to share your experiments and builds so that all members can have the opportunity to learn from your hard labor. When you say one of your builds “rotates several turns and then stops�.. was it self-acting or did you have to provide the initial push? Just curious…
MrTim -- I know what you mean about being rebellious. I consider myself somewhat of a “utopian idealist�. Some consider this a mental flaw. Others consider this a waste of time because the world is not a place that rewards idealism. “Funny, I’ve always believed that the world is what we make of it.�
pequaide -- I had to look up Willem Jacob ‘s Gravesande. On his wikipedia page, it says that due to the results of his most noted experiment, “Emilie du Chatelet subsequently corrected Newton’s formula E = mv to E = mv^2.� Why does it say she “corrected�. Is this a dumb question to ask? http://en.wikipedia.org/wiki/Willem_'s_Gravesande
I saw the thread you started in October of 2008 entitled “energy producing experiments“.. It’s going to be awhile before I can catch up to you!
-----
Regarding my comments on religion: When I was writing my initial post, I had no intention of bringing it up. I simply wanted to see if I could get some cold, hard facts. However, most of the questions that I had asked were in reference to personal “belief�. I guess I couldn’t help but illustrate the similarities.
I see many parallels between the two topics; the main one being that both sets of believers want the subject to be true. I think when people are in need, it is much easier to believe the happier ending.
Also, like God, PM hasn’t been proven. If a skeptic comes along and says “That isn’t true, because you have no proof�.. a believer would say “Well prove that it isn't true�. That’s the thing though; you can’t prove a negative. So like some who continue to search for God, some continue to search for PM.
greendoor -- I can’t agree with your first statement. I think there is a very clear difference between the two entities, and that there is a very good reason for the perpetual friction that has been occurring between them. I could never say it as eloquently as Anne Druyan, so I will let her do the talking: http://www.youtube.com/watch?v=yvVCpJCTM5w
There are many, specifically elite scientists, who don’t view science as simply a body of knowledge, but rather a way of thinking.. “a collaborative enterprise spanning the generations“. This video demonstrates it in a simple and pleasant way that I think anyone should be able appreciate. http://www.youtube.com/watch?v=9Cd36WJ79z4
I understand my statements may be upsetting to some, so if they would like to continue this specific topic, I think they should create another thread in the Off-Topic portion of the forum.
You are right, though. There are good and bad individuals in every group, as you pointed out in another message to me.
Grimer -- I’m really glad you posted your follow-up study so quickly. I will have to dedicate another post to it, as this one is getting to be extremely long and annoying(I’m sure). However, I think it is unfair to accuse Ralph of having a jaundiced view after he dedicated so much labor and time into it. This is, after all, a thread dedicated to skeptical reasoning.
I’m glad you mentioned the Buzz Saw, because Preston Stroud’s fantastic craftsmen skills which were illustrated on his videos are the reason I came here. He kept saying “My friends at Besslerwheel.com�. It seemed like a good place to check out!
Perhaps Ralph could give us more details. I’m sure the other newbies, like myself, would appreciate the learning experience.
Again, sorry for the long post. I want to touch on other topics, but wanted to get my personal opinions out of the way first.
Thanks.
"Science replaces private prejudice... with publicly verifiable evidence."
- aStillMoreGloriousDawn
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- Joined: Mon Nov 22, 2010 10:21 am
- Location: USA
re: Why should we bother trying?
Edit: It double posted...
"Science replaces private prejudice... with publicly verifiable evidence."
re: Why should we bother trying?
The following is a post from another thread. Since it develops the Keenie wheel analysis further it seems appropriate to copy it to this thread.
Analysis of Variance provides a good model for thinking about this.
With a simple two level analysis popularly known as Variance within and between batches one can have a significant variance within batches co-existing with a zero variance between batches. This case is very familiar to drivers who appreciate that static balance of a wheel can co-exist with dynamic unbalance.
But variance can exist at many levels. If we take a three level instead of the simple two level case then we can see that we can have zero variance at the first two levels but any amount of variance at the third level; variance within the individual components of the batch in other words.
Agreed, but this unbalance can be at a high derivative of position.jim_mich wrote:... But a perpetual motion wheel must be driven by some sort of unbalanced forces. ....
Analysis of Variance provides a good model for thinking about this.
With a simple two level analysis popularly known as Variance within and between batches one can have a significant variance within batches co-existing with a zero variance between batches. This case is very familiar to drivers who appreciate that static balance of a wheel can co-exist with dynamic unbalance.
But variance can exist at many levels. If we take a three level instead of the simple two level case then we can see that we can have zero variance at the first two levels but any amount of variance at the third level; variance within the individual components of the batch in other words.
Who is she that cometh forth as the morning rising, fair as the moon, bright as the sun, terribilis ut castrorum acies ordinata?
Grimer, I ignore your post in the other thread. I probably should ignore it here also... but... I wade in and hope I don't drown.
I fail to understand most of what you say. A derivative is something that gains its value from something else. I'm very familiar with financial derivatives. But I have no idea what you might mean by a "high derivative of position". Objects have x,y,z positions at any specific time.
I fail to understand most of what you say. A derivative is something that gains its value from something else. I'm very familiar with financial derivatives. But I have no idea what you might mean by a "high derivative of position". Objects have x,y,z positions at any specific time.
I worked Quality Control for twenty years. I very familiar with variances within and between batches of parts, but I have no idea how this might relate to perpetual motion.Grimer wrote: Variance within and between batches one can have a significant variance within batches co-existing with a zero variance between batches.
re: Why should we bother trying?
http://www.google.com/search?hl=en&lr=& ... tnG=Search
I'm using the first definition. I assume you were never taught calculus - but don't let that worry you. I expect you have plenty of company on this forum.
Faraday knew no calculus but it didn't prevent him from discovering induction.
Let's build from your understanding of variance within and between batches.
Suppose instead of gears your factory is producing matches. Your quality control operation may entail taking samples from each batch to determine the number of matches in a box. If the standard deviation of the number of boxes in a batch (the between box variation) goes above a certain value you will require the box counting process to be examined until the problem is sorted out.
There will also be a quality control requirement for the number of matches in a box. This will be the within box variation.
But there could also be a requirement for the length of the matches with a box since short matches could lead to someone burning their fingers, a more serious problem than merely receiving less than the correct number of matches in a box. That takes care of the third level of variation
So samples of matches will be taken to ensure that their lengths are within acceptable parameters.
After all, the firm doesn't want to get sued by some litigious parent because their little darling has burnt his fingers.
Now besides varying in length matches also vary in thickness. Suppose the firm doesn't bother to control this.
One day a tourist in an Airbus 380 on route to Hawaii decides to retreat to the bog for a quiet smoke and a read of his broadsheet. He lights a match but because the matchstick is too thin it breaks and the flaming match head flies out, lands on the paper setting it alight. Being closely confined and wearing lightweight cotton clothes the unfortunate tourist is soon well alight. He tears open the door and rushes down the aisle. With all those alcoholic beverages being consumed it isn't long before the whole fuselage is ablaze and 800 passengers and crew are on their way to Davey Jones' locker.
Some clever lawyer traces the problem to the out-of-spec match and sues your company for a $1,000,000,000.
A fanciful example I know but it does illustrate the potential significance of high derivatives of variance in manufacturing. High derivatives of position are also potentially important in the behaviour of machines. Recently a A380 airbus was within a whisker of crashing into the China sea as a result of a fatigue crack in an oil pipe.
http://www.bbc.co.uk/news/world-asia-pacific-11895106
Fatigue is a derivative of position which is so high that no one ever thinks of it in those terms.
That is why it is such a problem to engineers and has been responsible for many catastrophic failures. I'll stop there to avoid crashing this post by excessive length.
............Grimer, I ignored your post in the other thread. I probably should ignore it here also... but... I wade in and hope I don't drown.
Google gives a list of five definitions for the word derivative. Here are the top three.I fail to understand most of what you say. A derivative is something that gains its value from something else. I'm very familiar with financial derivatives. But I have no idea what you might mean by a "high derivative of position".
- the result of mathematical differentiation; the instantaneous change of one quantity relative to another; df(x)/dx
- a compound obtained from, or regarded as derived from, another compound
- derivative instrument: a financial instrument whose value is based on another security
I'm using the first definition. I assume you were never taught calculus - but don't let that worry you. I expect you have plenty of company on this forum.
Faraday knew no calculus but it didn't prevent him from discovering induction.
Let's build from your understanding of variance within and between batches.
Suppose instead of gears your factory is producing matches. Your quality control operation may entail taking samples from each batch to determine the number of matches in a box. If the standard deviation of the number of boxes in a batch (the between box variation) goes above a certain value you will require the box counting process to be examined until the problem is sorted out.
There will also be a quality control requirement for the number of matches in a box. This will be the within box variation.
But there could also be a requirement for the length of the matches with a box since short matches could lead to someone burning their fingers, a more serious problem than merely receiving less than the correct number of matches in a box. That takes care of the third level of variation
So samples of matches will be taken to ensure that their lengths are within acceptable parameters.
After all, the firm doesn't want to get sued by some litigious parent because their little darling has burnt his fingers.
Now besides varying in length matches also vary in thickness. Suppose the firm doesn't bother to control this.
One day a tourist in an Airbus 380 on route to Hawaii decides to retreat to the bog for a quiet smoke and a read of his broadsheet. He lights a match but because the matchstick is too thin it breaks and the flaming match head flies out, lands on the paper setting it alight. Being closely confined and wearing lightweight cotton clothes the unfortunate tourist is soon well alight. He tears open the door and rushes down the aisle. With all those alcoholic beverages being consumed it isn't long before the whole fuselage is ablaze and 800 passengers and crew are on their way to Davey Jones' locker.
Some clever lawyer traces the problem to the out-of-spec match and sues your company for a $1,000,000,000.
A fanciful example I know but it does illustrate the potential significance of high derivatives of variance in manufacturing. High derivatives of position are also potentially important in the behaviour of machines. Recently a A380 airbus was within a whisker of crashing into the China sea as a result of a fatigue crack in an oil pipe.
http://www.bbc.co.uk/news/world-asia-pacific-11895106
Fatigue is a derivative of position which is so high that no one ever thinks of it in those terms.
That is why it is such a problem to engineers and has been responsible for many catastrophic failures. I'll stop there to avoid crashing this post by excessive length.
Last edited by Grimer on Sat Dec 11, 2010 9:35 pm, edited 1 time in total.
Who is she that cometh forth as the morning rising, fair as the moon, bright as the sun, terribilis ut castrorum acies ordinata?
re: Why should we bother trying?
I still fail to understand the phrase "high derivative of variance". In your example of making matches, you say the third derivative was thickness. In my manufacturing experience (some were for aviation) many parts had 10, 20 or even 30 specifications that had to be held. And many times there were undefined dimensional defects. I've seen metal come from the mill having cracks and seems, and even on rare occasions with carbide objects embedded in the metal. So, would you say that the parts with 30 specifications had a "higher derivative of variance?" I just do not understand your usage or meaning of derivative in this context.Grimer wrote: but it does illustrate the potential significance of high derivatives of variance in manufacturing. High derivatives of position are also potentially important in the behaviour of machines.
I fully understand mathematical derivatives.
I fully understand chemical derivatives.
I fully understand financial derivatives.
But you seem to be trying to create some other derivative that you label "derivative of position". Yes, there are many things that derive some value from other things. Gravity derives its value from the size of the Earth. So do we call gravity a derivative force? The list could become infinite, for many things derive their features from other things.
I just do not see the need to use the term "derivative" in describing the movements of weights within a wheel. Yes, a weight can have many forces acting on it, and thus it position at any one time is derived by these numerous forces. But do we really need to cloud the conversation by using fancy labels like "derivative of position"?
Maybe it's the unfamiliar language that's giving you problems.
"In physics, jerk, also known as jolt (especially in British English), surge and lurch, is the rate of change of acceleration; that is, the derivative of acceleration with respect to time, the second derivative of velocity, or the third derivative of position. Jerk is defined by any of the following equivalent expressions."
http://en.wikipedia.org/wiki/Jerk_(physics)
"In physics, jerk, also known as jolt (especially in British English), surge and lurch, is the rate of change of acceleration; that is, the derivative of acceleration with respect to time, the second derivative of velocity, or the third derivative of position. Jerk is defined by any of the following equivalent expressions."
http://en.wikipedia.org/wiki/Jerk_(physics)
re: Why should we bother trying?
I've read the wikipages about jerk, jounce & snap etc.
What it seems to be saying is that in physics derivatives can keep coming if you look closer & closer [calculus].
N.B. IIRC my physics books generally made the assumption that acceleration is constant, probably for ease of calculations so that calculus isn't invoked.
We are all pretty much familiar with accelerometers, used in crash testing - they are used because whilst acceleration rate of change is important - so are any micro-accelerations or decelerations [derivatives] - the accelerometers measure the max or peak shock.
Many times it has been mentioned on the board the example of traveling to Mars & how long that would take etc - we have also mentioned it in the context of shifting weights positions inside a wheel - that is that while average velocity/speed is easy to think about, we often have to also think about the accelerations - so a ship traveling to Mars to get there the quickest [or weight shifting efficiently here on Earth] requires the highest average velocity - this entails rapid acceleration [assuming constant a] followed by rapid deceleration - hence a space ship must carry loads of extra fuel to both accelerate & decelerate to end the journey - simply carrying this extra energy for deceleration is inefficient as its mass also slows the initial acceleration phase.
Weights changing positional radius in a wheel for example need to be accelerated & then decelerated & this takes time but gravity acceleration force is constant, resulting in 'lag' [time to shift].
I'm not sure how using a derivative of position & time beyond constant acceleration shows us anything of use ?
Non constant acceleration will have peak periods of acceleration which will produce a high force for a short period of time.
Car manufactures are concerned about producing air bags that are malleable so that the maximum 'jerk' force is spread over the largest surface area which in turn allows the airbag to deflate slowly over distance allowing the jerk force to dissipate without harming the occupant because it's large force spread over large area for longer time & distance.
This seems to me to be .... Work Done = F . D is sheep's clothing, with the strength of the materials manufactured to withstand the peak acceleration derivative as seen on an accelerometer ?
So, how does knowing these derivatives help within a wheel in your context Grimer ?
What it seems to be saying is that in physics derivatives can keep coming if you look closer & closer [calculus].
N.B. IIRC my physics books generally made the assumption that acceleration is constant, probably for ease of calculations so that calculus isn't invoked.
We are all pretty much familiar with accelerometers, used in crash testing - they are used because whilst acceleration rate of change is important - so are any micro-accelerations or decelerations [derivatives] - the accelerometers measure the max or peak shock.
Many times it has been mentioned on the board the example of traveling to Mars & how long that would take etc - we have also mentioned it in the context of shifting weights positions inside a wheel - that is that while average velocity/speed is easy to think about, we often have to also think about the accelerations - so a ship traveling to Mars to get there the quickest [or weight shifting efficiently here on Earth] requires the highest average velocity - this entails rapid acceleration [assuming constant a] followed by rapid deceleration - hence a space ship must carry loads of extra fuel to both accelerate & decelerate to end the journey - simply carrying this extra energy for deceleration is inefficient as its mass also slows the initial acceleration phase.
Weights changing positional radius in a wheel for example need to be accelerated & then decelerated & this takes time but gravity acceleration force is constant, resulting in 'lag' [time to shift].
I'm not sure how using a derivative of position & time beyond constant acceleration shows us anything of use ?
Non constant acceleration will have peak periods of acceleration which will produce a high force for a short period of time.
Car manufactures are concerned about producing air bags that are malleable so that the maximum 'jerk' force is spread over the largest surface area which in turn allows the airbag to deflate slowly over distance allowing the jerk force to dissipate without harming the occupant because it's large force spread over large area for longer time & distance.
This seems to me to be .... Work Done = F . D is sheep's clothing, with the strength of the materials manufactured to withstand the peak acceleration derivative as seen on an accelerometer ?
So, how does knowing these derivatives help within a wheel in your context Grimer ?
re: Why should we bother trying?
Look forward to it.
It seems Pathfinder is just brighter than me.
It seems Pathfinder is just brighter than me.
You are more than capable of following the argument. The real problem is cognitive dissonance.
re: Why should we bother trying?
Yes, that must be it - I've been accused of being staid 'old school' more than once here & it sounds just like it ;7)
I guess, to break the dissonance, I will need a very convincing argument & maybe a quality experiment or two to open my eyes & mind.
Let's continue with the theory first & maybe I won't need step two.
I guess, to break the dissonance, I will need a very convincing argument & maybe a quality experiment or two to open my eyes & mind.
Let's continue with the theory first & maybe I won't need step two.