Author Topic: Twisting the standing parts of the falsely tied Hunter s bend  (Read 27515 times)

xarax

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Re: Twisting the standing parts of the falsely tied Hunter s bend
« Reply #60 on: April 24, 2015, 07:56:28 AM »
   Please show this in imagery; I don't see it.
 
   First, there IS, indeed, a bend where both first curves have the same, one-rope-diameter radius : the ABoK#1408.
   As ABoK#1408 is, obviously, different than the Butterfly bend, one can suspect  :), at least, that there is a fly in the ointment... and that Butterfly bend s first curves would be different, too.
   See the attached pictures - from the detail of the "top" view, one can clearly see what I am talking about so long...
   ( Click to enlarge )

   http://igkt.net/sm/index.php?topic=5269.msg34592#msg34592

« Last Edit: April 24, 2015, 08:16:30 AM by xarax »
This is not a knot.

Tex

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Re: Twisting the standing parts of the falsely tied Hunter s bend
« Reply #61 on: April 25, 2015, 05:19:10 AM »
 xarax said:
Quote
  I simply believe that ( provided that the fundamental geometry of the Universe does not change ), all knots "exist", in a sense, as potentialities ( Aristotle s δυναμει ) - just like numbers and mathematical theorems do. Therefore, when a  ... knot tyer "discovers" a knot .. he does not "invents" them. All intelligent civilizations in the Universe tie the same knots, simply they had not informed us about that yet.  :)

I hate to break your platonic bubble, but the same can be said of iphones.  Their form and structure is something which simply exists as a possible solution to the fundamental properties of the universe we live in, given the right initial conditions to put one together.  The iphone was thus also not invented, but was a  discovered form of matter (many Samsung or HTC enthusiasts would probably agree with that, but that's kind of a different argument)
« Last Edit: April 25, 2015, 05:20:16 AM by Tex »

xarax

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Re: Twisting the standing parts of the falsely tied Hunter s bend
« Reply #62 on: April 25, 2015, 11:59:33 AM »
I hate to break your platonic bubble, but the same can be said of iphones. 

 :) :) :)
To be precise,, it is sort of Pythagorean... :)
( Two less will-known inhabitants of this bubble, shown in the attached picture. )
I believe that the Universe is probably made of mathematics - or it is a product of a computer simulation, a computer game, made by a computer scientist ( and from the so-so skill of the construction, I would guess he is just an undergraduate student ).
1.
http://en.wikipedia.org/wiki/Mathematical_universe_hypothesis
"The theory can be considered a form of Pythagoreanism or Platonism in that it posits the existence of mathematical entities; a form of mathematical monism in that it denies that anything exists except mathematical objects; and a formal expression of ontic structural realism."
"we invent the language of mathematics but we discover the structure of mathematics."
2.
http://en.wikipedia.org/wiki/Simulated_reality
http://www.simulation-argument.com/
a. Human civilization is unlikely to reach a level of technological maturity capable of producing simulated realities, or such simulations are physically impossible to construct.
b. A comparable civilization reaching aforementioned technological status will likely not produce a significant number of simulated realities (one that might push the probable existence of digital entities beyond the probable number of "real" entities in a Universe) for any of a number of reasons, such as, diversion of computational processing power for other tasks, ethical considerations of holding entities captive in simulated realities, etc.
c. Any entities with our general set of experiences are almost certainly living in a simulation.

   At least one of the following statements is very likely to be true:
1.The fraction of human-level civilizations that reach a posthuman stage is very close to zero;
2.The fraction of posthuman civilizations that are interested in running ancestor-simulations is very close to zero;
3.The fraction of all people with our kind of experiences that are living in a simulation is very close to one.
« Last Edit: April 25, 2015, 02:33:07 PM by xarax »
This is not a knot.

Dan_Lehman

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Re: Twisting the standing parts of the falsely tied Hunter s bend
« Reply #63 on: May 01, 2015, 10:35:17 PM »
   Please show this in imagery; I don't see it.
 
   First, there IS, indeed, a bend where both first curves have the same, one-rope-diameter radius : the ABoK#1408.
   As ABoK#1408 is, obviously, different than the Butterfly bend, one can suspect  :), at least, that there is a fly in the ointment... and that Butterfly bend s first curves would be different, too.
   See the attached pictures - from the detail of the "top" view, one can clearly see what I am talking about so long...
   ( Click to enlarge )

   http://igkt.net/sm/index.php?topic=5269.msg34592#msg34592
Thank you for the imagery (and one citation w/neat highlights!).

I remain unconvinced : what you show is (a) a particular
dressing of your own fancy, and not something common [n1],
methinks --where a common guidance (for the fig.8
but presumably w/broader effect) is to smooth away
crossings, which would loose your apparent broad turn--;
and (b) you are making a dubious static analysis,
and not seeing things when "push comes to shove"
--where it is likely that the crossing-over-other will
change to pulled-off-of-being-over-other, resulting in
a hard turn around the eye leg, for the most part.

[n1] In the common orientation, the *crossing* of S.Parts
comes in a sense where they are turning around the
abutting eye legs --i.e., the one rising to the other's falling--
rather than as you show, the one changing position over
the other (at that point, they'd be at their levels).]

Similarly re #1408.  (One might cite the zeppelin end-2-end knot
as having such weakness.  The curvatures in these knots
are often not so bad, with maybe #1452 & #1425 likely
good, & Harry Asher's shakehands & SmitHunter's bend
less so (with the latter having a version not-so-bad (which,
in one test I had done, was not-so-much-better!  :P )).


--dl*
====

xarax

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Re: Twisting the standing parts of the falsely tied Hunter s bend
« Reply #64 on: May 01, 2015, 11:49:16 PM »
...where a common guidance (for the fig.8 but presumably w/broader effect) is to smooth away crossings, which would loose your apparent broad turn--;

  In this knot, the X-crossing can move to the one "flat" side of the knot or to the other - but it an not be smoothed out, and disappear ! Think about this a little bit, and you will see why.
   Whatever side this X-crossing is pushed to be transported to, and to be fixed at, it will remain as an X-shaped crossing - and once we have this crossing, the one first curve will pass around the other, and it will have to trace a wider path, so it will be more gentle.
 
Quote from: Dan_Lehman link=topic=3204.msg34863#msg34863 date=1430516117
you are making a dubious static analysis, and not seeing things when "push comes to shove"...

   True. I had noticed that a number of times. We can never be sure how much/bad a nub will be deformed, after a really heavy loading. However, as I said above, given the fact that there will be a X-shaped crossing somewhere ( a tangible/material proof of the asymmetry of this knot ), I predicted that there will be a difference in strength - and I was proven to be wrong, yet another time !  :) Not because of the absence of the asymmetry, but probably because such the strength differences due to such geometrical differences, especially in thin lines, are not significant or even measurable at all.

the one rising to the other's falling-- rather than as you show, the one changing position over the other

   As I said, this is irrelevant ! Which line goes over which, and in which point/side of the knot, does not matter. The one has to be wider than the other, for pure geometrical reasons. Take any flexible rod which retains, more or less, its circular cross-section everywhere, and try to make a 3D model of the knot in which the two first curves will have the same diameter. You will see that it is impossible.
« Last Edit: May 01, 2015, 11:56:58 PM by xarax »
This is not a knot.

Tex

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Re: Twisting the standing parts of the falsely tied Hunter s bend
« Reply #65 on: May 02, 2015, 02:13:44 AM »
xarax I'm not sure why you're giving in now.  As much as I don't care, and even mocked you a little,  still a man should not give up his principles too easily ;) .   You had already well established that you thought 5% would be huge and 1% would even be big.   1% has certainly not been ruled out, let alone 0.1%.  There is clearly a geometrical difference.  This is undeniable.


xarax

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Re: Twisting the standing parts of the falsely tied Hunter s bend
« Reply #66 on: May 02, 2015, 02:44:27 AM »
 
There is clearly a geometrical difference.  This is undeniable.

  Dan Lehman remain unconvinced - and myself I admit I want to see to believe ( meaning, to measure the differences of the first curves of knots near or after rupture ). I have seen strange things happening inside nubs under heavy loading, probably because of torsion, which we had not taken into account in our discussions.
   And I repeat that we have not established yet that strength of knots is scale independent. Especially when the construction of the ropes ( the way the fibres, and the bundles of fibres, are interwoven into their core ) certainly does depend on the sixe of the ropes. Even ropes of the same brand sold under the same name, are constructed differently in small and large sizes.
   I expect that the differences would be bigger ( I do not know if they will become significant or not, whatever that may mean...) when the Butterfly knot is tied on larger sizes - the sizes usually used for climbing and rescue purposes ( 9-12.5mm ).
This is not a knot.

Dan_Lehman

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Re: Twisting the standing parts of the falsely tied Hunter s bend
« Reply #67 on: May 02, 2015, 06:58:53 AM »
... the one rising to the other's falling-- rather than as you show,
the one changing position over the other

   As I said, this is irrelevant ! Which line goes over which, and in which point/side of the knot,
does not matter. The one has to be wider than the other, for pure geometrical reasons.
At the point of U-turn, the reversal of direction,
which is our focus, is where the assessment of
curvature should matter, and in your highlighted
image above one can see that the there-indicated
wider-turning one should simply slide (its crossing
over point) leftwards and sharpen its U-turn (which
is at the right).

OTOH, I'll grant that this U-turn shows more similarity
in sharpness to the other end's when loaded "through"
(end-2-end), than qua eye-knot --where there is some
bearing-against (if not crossing over) of the then SPart
vs. the unloaded other end.  (#1408 does pretty well
in rounding its U-turn as it symmetrically twist-tightens
its ends, I think; whereas these things are problematic
for the zeppelin.)

Quote
Take any flexible rod which retains, more or less, its circular cross-section everywhere,
and try to make a 3D model of the knot in which the two first curves will have the same diameter.
You will see that it is impossible.
Nonsense : in THIS plan, you have --for the butterfly--
the opposing SParts coming in left vs. right with one atop
the other as they pass across the "abutting" eye legs,
and then one U-turns --the 1dia of eye leg-- from below
upwards, the other complementarily and also 1dia around
an eye leg downwards; and THEN somewhere away from
the U-turns of focus, there is an asymmetric crossing of
over/under --to my side of the debate, make it at the
opposing S.Part's U-turn, reaching then into the collar.

The part that you fill the bottom of your larger/red circle
with I say moves the crossing-over point leftwards to make
that circle a horizontally disposed ellipse, and at its point of
focus ("U-turn") on the right you have an equal 1-diameter
turn as for the opposing side.  That is the how-I-see-it that
led me to this question.  One will need to set this left-side
eye leg pretty tight to deform the left SPart's shaping
around this area to make the shifting I describe here
such as would then otherwise maybe give curvature,
"bearing against" to that left SPart.  --and I don't see
this happening, as a general rule.  (And now we're into
vagaries of dressing, fine-tuning an orientation!)

But space is short, and the crossing over ... can it really
influence much the U-turn's sharpness?  --and moreover
the vagaries of what happens when eye-loaded?
.:.  So, I do see your view, but still find it dubious.
I'm more happy to pursue the crossed-legs version,
with distinctly different overhand components each
of which looks to curve rather favorably (though, again,
when loaded with the eye, how things actually shape up
is less clear, and probably differs with rope type).


--dl*
====
« Last Edit: May 02, 2015, 07:04:22 AM by Dan_Lehman »

xarax

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Re: Twisting the standing parts of the falsely tied Hunter s bend
« Reply #68 on: May 02, 2015, 01:38:12 PM »
  The issue will be resolved instantly, when knot rigger will test Butterfly loops tied on thicker ( climbing and rescue ) ropes ( 9-12.5mm ), and measure the first curves of the almost solidified knots, after the rupture. Hic Rhodus, hic saltus !
This is not a knot.

Dan_Lehman

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Re: Twisting the standing parts of the falsely tied Hunter s bend
« Reply #69 on: May 03, 2015, 07:49:10 AM »
  The issue will be resolved instantly, when knot rigger will test Butterfly loops tied on thicker ( climbing and rescue ) ropes ( 9-12.5mm ), and measure the first curves of the almost solidified knots, after the rupture. Hic Rhodus, hic saltus !
Again, measuring post-rupture is dubious at best.
And beyond that there are so many factors to consider
--prior measurement, even the dressing,
and still one can wonder at material, firmer vs.
compressible rope and so one.
Even the actual making of such a measure of
curvature I think entails difficulty in placing one's
measuring points and so on.

--dl*
====

xarax

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Re: Twisting the standing parts of the falsely tied Hunter s bend
« Reply #70 on: May 03, 2015, 09:27:02 AM »
...factors to consider :
1. even the dressing,
2. material, firmer vs. compressible rope

1. Probably wrong. Under such heavy loading, the differences in the initial dressing will, most probably, be smoothened out.
2. Correct. However, I expect that the differences in the two curves will be analogous, in firm and compressible ropes.

  Regarding the way one measures "curvature", it is true that things are not so simple, because curvature is a local thing, and varies along a curvilinear segment. That is why I asked for a measurement of the ( external ) width of the (total) "curve", which, when the angle between the first and the second segment at the ends of it is "negative" ( when the ends are parallel, it is zero degrees - when the ends are aligned, and there is no curvature anywhere, it is 180 degrees ), it is easy and unambiguously measurable.
« Last Edit: May 03, 2015, 09:28:40 AM by xarax »
This is not a knot.