dust collection ducting

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But he masked the point by the assertion of zero for both...which probably means some will just write off the message as well as the messenger...

Reply to
Duane Bozarth
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That's a pretty novel understanding of probability theory! How large does the chance of something happening have to be before its probability gets to be non-zero?

Which is dramatically different from what you said before. You seem to be confusing the probability of an event with what most Americans would say the probability of that event was.

yep. And maybe that "reasonable estimate" is 1/1000th of the probability of all life on Earth being destroyed in an asteroid hit. Risks like that I can live with!

I agree.

Reply to
alexy

Not the point

Reply to
Steve Decker

if a little enthusiasm for the argument is gonna kill the message, you'd better shut down usenet right now.

sure, he probably should have goven odds of a few billion to one rather than zero. either way, he was closer to truth than you are.

Reply to
bridger

his or yours?

Reply to
bridger

On Friday 28 Jan 2005 3:34 am, Mark & Juanita scribbled:

To add to the pedantry, if the quantum effect of neutron decay happened all at once in the bucket (a negligible but not zero probability), the helium could be changed into deuterium and/or berillium and/or lithium and hence burst into flames. Hence, the probability is not zero.

Reply to
Luigi Zanasi

....

Actually, I've never said anything about the actual numerical value, but I would assert that it >0 which would put my estimate closer... :)

My chief complaint is the assertion of problem in any system, sight unseen that is implicit in the proposition. The reference he quotes, in fact, says specifically it can't be totally ruled out, but is merely highly unlikely for home-shop systems, anyway.. If people say that, I'll not complain a lick...if the claim the problem is non-existent I'll continue to think that unsupportable. :)

Reply to
Duane Bozarth

... snip

Alright, stepping into the realm of pedantry: From the axiomatic definitions of probabilty theory (Papoullis, Probability, Random Variables, and Stochastic Processes), "The probability of an event a is a number P(a) assigned to this event. This number obeys the following three postulates: I. P(a) is positive: P(a) >= 0 II The probability of the certain event equals 1: P(S) = 1 III. If a and b are mutually exclusive, then: P(a + b) = P(a) + P(b)" [Version I have at home is McGraw-Hill 1965 version, page 7]

Note: from (I), P(a) = 0 is a valid probability. For the examples stated, "a bucket of water bursting into flame", or "a unit of helium bursting into flame", or "conservation of mass in a chemical reaction holds" the probability of these events can be stated to be zero. Unless you are going to imply that the laws of physics and chemistry are muteable

--- if that is the case, then the whole fundamental fabric of science and technology is essentially destroyed. i.e., there is no, zero, zilch, zip, nada chance that helium will burn (i.e. oxidize) in an chemical reaction -- helium is an inert gas, it cannot combine with oxygen, it *will not* burn. This is more than "empirical evidence", it is a fundamental element of the chemical nature and properties of elements. If we can say that there is some non-zero probability that elements will behave willy-nilly contrary to their fundamental chemical and nuclear properties, we are wasting our time with science and technology. Thus, in these cases, one can indicate that the probability of those events occuring P(a) = 0, and in addition, the probablity of those events occuring are the impossible event. Further, from II, it is also possible to have a certain event, for which the probability = 1.

It is also important to note that one must distinguish between the impossible event, and those events with probability = 0. For example, the probability P(t = t1) = 0 may be true, but not necessarily an impossible event. Same is true that even though the probability of an event = 1, this is not necessarily the certain event. However, for the impossible event P(a) = 0, and for the certain event P(a) = 1. But this is a side detour to the original statement. The fact is that it is *not* inherently incorrect to state that a probability is exactly identical to zero.

+--------------------------------------------------------------------------------+ The absence of accidents does not mean the presence of safety

Army General Richard Cody

+--------------------------------------------------------------------------------+
Reply to
Mark & Juanita

Hmmm. What if the die were a faulty manufacture? Remember, you referred to a six-side die which could have seven "spots" on one of those six sides due to a manufacturing error . . . or it could be intentionally made that way. Perhaps your statement of a zero chance of a seven should be restated to clarify that none of the six side have more than six "spots." ???

Glenna

Reply to
Glenna Rose

True, see my other post

This is imprecise and incorrect

No, in a set consisting of the elements {1,2,3,4,5,6} not only does the probability of selecting a 7 from that set = 0, it is an impossible event since 7 is not *in* the set.

This is confusing fact and opinion. The answer to the question, do you think this will happen and getting the answer, "no" is an opinion. The facts were a) the twin towers exist in physical space on Earth, b) airliners are capable of flying within the atmospheric envelope and spatial area occupied by the twin towers, c) there is no physical barrier to airliners and the twin towers spatially intersecting one another. A more apt analogy for the impossible event would be, "can airliners strike two lunar landing sites within minutes of each other and destroy those historic sites?" There, the answer is the impossible event because a) airliners are incapable of operation the vacuum of space, and b) airliners do not have the sufficient thrust to leave the gravitational field of the earth.

+--------------------------------------------------------------------------------+ The absence of accidents does not mean the presence of safety

Army General Richard Cody

+--------------------------------------------------------------------------------+
Reply to
Mark & Juanita

the possibility of "faulty manufacture" was eliminated in the specifications -- it was stated that the _specific_ die being used was:

(a) a regular hexahedron -- this means that it has precisely SIX faces, no more, no less.

(b) had labels on the 6 faces that were from an 'enumerated list'. There were precisely SIX elements in the enumerated list. There is no 'room' for any other value.

(c) one that did *not* have 'spots' on it. The faces were labelled with Arabic numbers. "1", "2", "3", "4", "5", and "6", according to the enumerated list.

It *is* possible to have *A* die where you _could_ roll a '7' -- I've seen ones in the shape of a dodecahedron, and even an icosahedron. However, it is *NOT*POSSIBLE* with the die specified in the example. The mathematical probability of the event specified ('rolling a "7") with *that* die is _precisely_and_exactly_ ZERO.

Sorry, but the specifications of the example were 'deliberately and maliciously constructed' in a manner such as to eliminate such extraneous digressions. :)

Reply to
Robert Bonomi

... snip

oops, that should have either been the certain event P(a) = 1, or restated as "conservation of mass in a chemical reaction does not hold" P(a) = 0.

+--------------------------------------------------------------------------------+ The absence of accidents does not mean the presence of safety

Army General Richard Cody

+--------------------------------------------------------------------------------+
Reply to
Mark & Juanita

Go back to your basic probability text and recheck your facts.

All of which strays far from the point of dust explosions.

They can and do happen.

The point, again, is to refrain from absolutism.

Reply to
Steve Decker

My Brains full....can I go home...;)

Reply to
Schroeder

Why do you say this? Not everyone believe in the absolutely no absolutes BS like some in here. There are things that are simply not going to happen ad some like me believe more in statistical significance. If the chance is so small that it becomes insignificant, this it simply has no chance. I can't speak for you but I have things of real significance to worry about.

Reply to
TBone

With all of the dust collectors in use in home shops and the fact that not a single instance can be found of this happening, this it is safe too say that it simply will not happen and until even a single instance occurs, anything else really is nothing more than paranoia.

Reply to
TBone

Then it wouldn't be a six sided die anymore, case closed.

Reply to
TBone

But you just changed the helium into something else so the probability of HELIUM bursting into flames is still ZERO.

Reply to
TBone

All of which begs the challenge I originally posed: cite a single example of a dust explosion occuring in a home shop dust collection system.

With your absolute certainty that they do, it should be dirt simple to find a cite. Just one. Come on. You know everything. Surely you can come up with one verifiable example. I'll leave the wreck forever if you can come up with a single documented instance.

Uh, where does that leave "[t]hey can and do happen"?

- - LRod

Master Woodbutcher and seasoned termite

Shamelessly whoring my website since 1999

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Reply to
LRod

Whatever.

You win, LRod!

You da man !!

Now hear this everyone:

LRod hath decreed that there will NEVER, EVER, NEVER be a home shop dust explosion. Not EVER. ZERO chance. ZIP, ZILCH. NADA !

Let all Rod's people say AMEN.

You has done converted this wayward sinner, LRod.

Can I get a AMEN ? I has SEEN DA LIGHT !

Now everybody shake hands and go make sawdust !

Reply to
Gus

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