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drector
Jun 5, 2003, 8:32 PM
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In reply to: In reply to: Wire gates are thinner and more prone to cutting through the rope if the gate gets cross-loaded. This is incorrect. It has been tested in the lab and shown to be false. Wire gates will not cut your rope. -Jay
Jay,
Which lab? I hadn't yet heard that it was official.
Well it used to be one of the cons until it was debunked. I never worried about it anyways.
Dave
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canadianclimber
Jun 8, 2003, 5:39 AM
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In reply to: Hotwire has shrouded gate. Quickwire doesn't.
Can someone explain what a shrouded gate is and why its better? Thanks
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alpnclmbr1
Jun 8, 2003, 6:12 AM
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a shroud is a protective nose(right where the gate interacts with the biner) on the biner that prevents having the gate open as the nose of the biner scrapes against the rock.
somebody have a picture?
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trenchdigger
Jun 8, 2003, 6:46 AM
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Mech Engr. here...
vanny37 - Moment of inertia would definitely play a part. Your analysis is pretty rough (rect. vs cyl. coords, assuming gate is perpendicular to momentum, etc.) so I wouldn't put much faith in the numbers. But the bottom line is that the greater moment of inertia of the gate of a solid gate 'biner would impact the flutter of the gate.
wlderdude - You're also somewhat correct, assuming the initial spring constant (when the gate is closed) of the non-liner spring is greater than the spring constant of the linear springed 'biner you're comparing AND the impact is not too large. I have noticed though, that not all wiregates have the "spring" for the gate set up in that way. Some act as a linear spring too. Depends on the 'biner.
Let's look at each difference individually...
Comparing two 'biners - a wiregate and a solid gate - and assuming both are IDENTICAL other than the gate, the solid gate 'biner is more likely to "flutter" open than the wire gate 'biner.
Comparing two identical biners - two solid gates or two wire gates with identical gates and linear (but NOT identical in stiffness) springs- one with a greater spring constant is less likely to flutter.
A 'biner with a non-linear spring would have to be evaluated over an integral dW = F*r*d(theta) where F is a non-linear function describing the spring force. Comparing that 'biner to an identical 'biner with a linear spring with a constant within the range (less than the max, greater than the min) of the non-linear spring, the gate could open MORE or LESS than the 'biner with a non-linear spring depending on the "strike force" in your test (ie how hard the back of the 'biner hits the rock).
So you'd really have to extensively analyze each specific 'biner to figure out which would be more likely to open in such a situation, then make comparisons. The others have some good points on the advantages/disadvantages of different types of 'biners.
As for the gate cutting the rope - I would bet that the gate would give way before the rope in such a situation.
Enough gibberish for tonight...
~Adam~
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daisuke
Jun 8, 2003, 7:47 AM
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apart from all what has been said, if you're going to buy wiregate biners I can only say that the ONLY wiregate biners out there are the ones made by Kong, they flutter less than any other I've seen and are much MUCH easier to clip into, plus they're about the strongest things out there.
BD biners are nothing compared to Kong, if you don't agree then go test them out at the store
D
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sheldonjr
Jun 8, 2003, 8:17 PM
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In reply to: Wiregates deform, absorbing the load as they do so. Thats why wiregate crossload strenth is comparable to a regualr gate.
How much crossload can a wiregate take before it gets deformed? I'm not so much interested on how much it'll hold before failing, but how much it could take on a regular basis.
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jt512
Jun 8, 2003, 8:53 PM
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In reply to: In reply to: In reply to: Wire gates are thinner and more prone to cutting through the rope if the gate gets cross-loaded. This is incorrect. It has been tested in the lab and shown to be false. Wire gates will not cut your rope. -Jay Jay, Which lab? I hadn't yet heard that it was official.
I want to say that it was done by Black Diamond, but I'm not sure. If you search the rec.climbing archives at groups.google.com, you should be able to find some details on the testing.
-Jay
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vanny37
Jun 9, 2003, 9:56 PM
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In reply to: Your analysis is pretty rough ... so I wouldn't put much faith in the numbers.
Yea, I know. Like I said many times, it's probably not right, but close enough. Sometimes you gotta use rough numbers to get a point across.
In reply to: A 'biner with a non-linear spring would have to be evaluated over an integral dW = F*r*d(theta)
Learn something new everyday, thanks!
What you said about the spring is correct and maybe I just wasn't clear enough; the spring only comes into play after the gate has begun to flutter, or in other words, its inertia has made it swing. Only then does it matter what the spring does.
I really have yet to find a solid gate that does not flutter less than a wire gate, regardless of the spring. Leading me to think that the forces generated by the inertia of a solid gate are greater than what any spring on any carabiner will compensate for. Hence why the inertia is the driving factor and the spring secondary to how much flutter happens.
Thanks for the new input!
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yomomma
Jun 9, 2003, 11:03 PM
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question: has anyone ever heard of a rope popping out of a biner due to gate flutter? Is not the danger of gate flutter in the fact that open gate strength is much less than closed gate strength?
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jt512
Jun 10, 2003, 2:53 AM
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In reply to: question: has anyone ever heard of a rope popping out of a biner due to gate flutter
No. However, I have heard of two instances of draws becoming unclipped from bolts when the leader fell. In both cases the carabiners on the bolt end of the draws were wiregates. My guess is that the wire gates caught on the bolt heads, openning the gates, and allowing the draws to become unclipped.
-Jay
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overlord
Jun 10, 2003, 11:21 AM
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i use wiregates because theyre lighter and easier to clip.
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pelliott
Jun 10, 2003, 11:39 AM
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Listen to what jt512 said. If you do use wiregates on the bolted side, you have to be much more careful about the direction that you clip. They pry open easier.
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noshoesnoshirt
Jun 10, 2003, 5:15 PM
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strange synchronicity; i've been thinking a lot about gate flutter these days.
vanny37, i think you have made some valid points concerning the moment of inertia. one thing though; no one has mentioned the vibrational effect caused by the drag force of the rope running across the 'biner.
i was under the impression that this force would (for a period of microseconds perhaps) cause the 'biner to vibrate on one of its natural harmonics, and this was a potential cause of gate flutter.
any comments? and does anyone know of any existing studies documenting vibration-related gate motion? i'd really like to design an experiment for this phenomona.
kerry
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redpoint73
Jun 10, 2003, 5:30 PM
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In reply to: How much crossload can a wiregate take before it gets deformed? I'm not so much interested on how much it'll hold before failing, but how much it could take on a regular basis.
Don't know. Probably a question best posed to Black Diamond. They don't have any info on their website. In any case, you shouldn't be worried about crossloading your biners on a "regular basis". If it happens during a fall of any great distance, your first experience might well be your last.
In practice, I would say that if you see any noticable bending of the gate, you should probably replace it. At the very least, the bending might interfere with how the gate opens and closes. If the gate of any kind of biner is slightly out of line, it will prevent it from closing properly over the nose of the biner.
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kevlar
Jun 10, 2003, 5:35 PM
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The answers are out there...OSH
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redpoint73
Jun 10, 2003, 5:41 PM
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Uhhh . ... what?
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winter
Jun 10, 2003, 9:32 PM
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Check out the DMM wiregates. They make ones (forget the name of the specific draws) that have a wire gate adn no hook (like the BD positron). They are sweet, basically they look liek regular wire gates, but the wire part "twists" and there is a ball at the end of it that fits into a "socket" in the nose. Very clever.
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kzemach
Jun 10, 2003, 10:23 PM
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In reply to: question: has anyone ever heard of a rope popping out of a biner due to gate flutter? Is not the danger of gate flutter in the fact that open gate strength is much less than closed gate strength?
I can personally attest to the second part of that. I have taken a hard fall with a solid gate biner that had the gate open upon impact, as the entire biner is stretched and deformed, and there are no gate slippage marks. It held, but it was a little scary.
Incidentally, on the same trip (a three day aid climb in Yos), I got lazy on the last pitch and was hauling a haul bag using a regular biner instead of a locking biner (not that it SHOULD matter) on the ascender attached to my harness (to pull the haul line that went through the pulley). There was a lot of friction/drag on the bag, and on one of my static-ish pulls, then entire biner 'exploded.' Basically, the pin holding the gate ripped out.
Now, I haven't done any calculations, but there's no way I'm that strong. Can't imagine I can leg press more than about 700 static pounds anymore, and we all know biners are stronger than that. Haven't looked at the fracture surface in an SEM yet, but my guess is that over time, a fatigue crack developed. However, you can't SEE such a crack, even when loading the biner, with a solid gate! However, I believe with a loaded (static) wire gate biner you should be able to see moderately sized and developed fatigue cracks opening. Can anyone confirm/comment on this?
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ambler
Jun 10, 2003, 11:08 PM
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In reply to: In reply to: question: has anyone ever heard of a rope popping out of a biner due to gate flutter? Is not the danger of gate flutter in the fact that open gate strength is much less than closed gate strength? I can personally attest to the second part of that. I have taken a hard fall with a solid gate biner that had the gate open upon impact, as the entire biner is stretched and deformed, and there are no gate slippage marks. It held, but it was a little scary.
Something similar happened to me, but the rope did pop out, turning a 10 foot freefall into 30. The (solid) gate ended up outside of the carabiner body, with no other visible damage. Unfortunately that carabiner was still up there near my high point, with the rope no longer clipped through it.
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vanny37
Jun 12, 2003, 10:32 PM
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noshoesnoshirt,
harmonic resonance opening a biner... never heard of it. and I wouldn't know where to begin either
however, I do know an Mech. engineer who used to work for GM as a sound engineer; all he worked on was the vibrations of vehicles at speed
during one of our inebriated engineering discussions I'll try to remember to bring up the subject :wink:
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deadfish
Jun 12, 2003, 11:42 PM
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Gate flutter has to do with harmonic vibration induced by the sliding rope, not inertia. If you decrease the mass of the gate (as with a wiregate biner), the resonant vibration frequency of the gate increases to a range outside the frequency range induced by the rope sliding through it. Decreasing the mass also happens to reduce the likelihood of inertial opening.
In terms of clearing up all the semantics, Hank Moon from Petzl has done a great job of summarizing:
"In the interest of correcting a popular error in concept and syntax,
it should be noted that "whiplash" is not the same phenomenon as "gate
flutter." Whiplash refers to a peculiar behavior of rope that was
witnessed in laboratory drop tests conducted in Lyon, France in the
late 80's/early 90's (memory failing).
The tests were filmed with a high speed video camera in order to study
the affects on rope and 'biners in slomo. It was in these videos that
the "whiplash" phenomenon was observed: when the load released, the
rope would first drop down through the biner, then as the load fell,
reverse direction (now passing up through the biner). The slack rope
would then loop up high above the 'biner (up to 4 feet or so if memory
serves - haven't seen the videos in years) and finally "whip" against
the 'biner as the test load bottomed out. Quite frequently, the rope
would unclip itself from the 'biner as it did the whippin' thang.
Presumably, actual whiplash doesn't happen so much (if at all) in real
climbing due to mostly low fall factors, and friction between rope and
rock. True whiplash seems to be a high-FF lab phenomenon. You can
simulate whiplash at home with an anchored draw - doorknob works fine
- and accessory cord. Run the cord through the draw and give a swift
yank on one end to see the loop appear above the draw. Now imagine
much heavier cord and much, much, higher velocity and energy.
Gate flutter was also (first?) observed during these same tests, and
to my knowledge, has not been witnessed outside of a laboratory.
However, since we know it can happen in a lab, it has been suspected
as a possible cause of carabiner failure in the field. Keep in mind
there are many other such causes, most of which result in an open
gate: 'biner smacking rock, gate pushed open by rugosity, 'biner
loaded over edge, etc. True gate flutter results from vibrations
imparted to the carabiner from the rope moving rapidly through it. A
momentary opening of the gate due to the frame hitting rock, or sudden
loading/orienting of the draw is not gate flutter. The confusion of
the two concepts may have arisen due to gate openings observed when
the draw is suddenly loaded or "whipped". To finish off gate flutter,
it is important to note that carabiner failure during the tests
occurred so seldom that researchers resorted to taping the gates open
to induce failure. All failures occurred only in high-FF situations."
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vanny37
Jun 13, 2003, 12:41 AM
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ok, I'm learning new stuff everyday.
So I guess I should be asking is what are we really discussing here? Why 'biners open when impacted or gate flutter? According to deadfish I guess we (I) were on the first one.
Do you have any more stuff on this, I had never heard of that before! Interesting stuff.
Here's a little blurb from a BlueWater Technical Manual I found real quick:
In reply to: All BlueWater karabiners have high gate open strengths ranging from 7kN to 9kN. The UIAA requires no less than 7kN to minimize the possibility of failure if a karabiner is inadvertently loaded when the gate is open. This most often happens when: (1) the karabiner gate is forced into the rock due to improper rigging, (2) the karabiner is slapped into the rock causing the gate to open temporarily, or (3) in the event of gate flutter caused by the vibration of the rope running rapidly, under tension, through the karabiner in a fall. For this reason, it is important to make sure karabiners are properly rigged and to use karabiners with high gate-open strength for added security.
It lists gate flutter and inertial openings separately
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noshoesnoshirt
Jun 15, 2003, 2:37 PM
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hey deadfish, do you know where to find the original data from the lyon whiplash studies?
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dirtineye
Jun 15, 2003, 4:59 PM
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DMM Wirelock biner. Because nothing else compares to it.
And remember, sport climbing sucks.
Gawd, a double baited troll-- I've read too many drkodos posts today. OOPS, that's three.
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alpnclmbr1
Jul 4, 2003, 5:51 AM
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Search Result 108From: Chris Harmston (chrish@bdel.com)
Subject: Hotwire Questions and Answers This is the only article in this thread
View: Original FormatNewsgroups: rec.climbing
Date: 1995/09/29
Chris Harmston
Quality Assurance Manager
chrish@bdel.com.
August, 1995
Fellow climbers:
Thanks for your interest in the HotWire Carabiner. The questions we've
been sent via mail and e-mail about the HotWire show that many climbers
are curious about how this unique biner works. We are glad that you
don't take your gear for granted and want to know more. This flyer
addresses the most frequently asked questions about the HotWire, and
clarifies some common misconceptions about its unusual design. Black
Diamond would like to hear any additional comments you might have.
Contact us at:
Black Diamond Equipment, Ltd.
2084 East 3900 South
Salt Lake City, UT 84124 USA
Phone: (801) 278-5533; Fax: (800) 775-7625;
E-Mail: climb@bdel.com
Why is the HotWire so strong?
There are two basic reasons: body shape and gate material. The HotWire's
body is designed so that a significant percentage of its mass is
concentrated at the nose--the most common breaking point for biners--to
give the HotWire its superior 25 kN closed-gate strength. The HotWire can
afford to have a thicker, stronger nose and still maintain its light
weight due to the negligible mass of the gate itself. The body's
cross-section design gives the HotWire its open-gate strength; at 10 kN,
few biners can rival it.
Unlike conventional carabiners, the HotWire's gate is not aluminum. The
gate wire is made of stainless spring steel which significantly exceeds
the strength of an aluminum gate.
Is the wire gate as strong as a conventional gate when it is
cross loaded?
It's not just as strong, it is stronger. When a conventional carabiner
gate is cross loaded beyond its strength it will break, causing total
failure of the biner. At the load where aluminum gates start failing,
the HotWire's gate will have already bent but remains an intact "closed
loop." Although the HotWire gate may deform at a lower cross load than a
conventional biner, the force which finally causes the HotWire to fail is
about 20% greater than the failure load for conventional biners.
We test the HotWire's minor axis strength by applying a load
perpendicular to the gate, pulling the biner apart between two 12-mm pins
or between a pin and a climbing rope. Out of the one hundred-plus
HotWires we have pulled to failure in a cross-load configuration, none
have failed because the gate wire broke. In fact, in cross-load tests
the HotWire is stronger than any other carabiner that Black Diamond
makes.
HotWires easily surpass the updated UIAA and CEN standards which require
carabiners to have a minimum 7 kN strength along the minor axis. But
it's not only the rating that's important; the method used to establish
the rating is just as relevant to a biner's strength. By using the Three
Sigma Rating System we establish ratings which are extremely
conservative. This means that the 7 kN minor axis rating we give the
HotWire is a significantly lower number than what our tests indicate the
actual cross-load strength is. (Contact us for a copy of our Spring 1995
Catalog or our Carabiners Pamphlet if you'd like more information on the
Three Sigma System.)
Could the gate of the HotWire damage a rope?
The possibility of shredding your rope if it should cross load a
carabiner's gate is sobering. Cross loading any carabiner is very
dangerous, both for the biner and the rope, and should be avoided at all
costs. Refer to our Carabiners Pamphlet for advice on carabiner use.
We performed a series of tests cross loading HotWires with a 10-mm rope,
to measure the effects that the wire gate had on climbing ropes. We
preformed similar cross-load tests on regular carabiners for comparison.
The gate wire itself does not cause rope damage, although most types of
biners caused moderate rope damage near their breaking points.
Carabiners can, in extremely rare instances, slice a rope sheath if the
biner is cross loaded. Because the HotWire's gate is a smooth continuous
loop, the absence of interruptions or sharp edges on the wire gate can
actually help to prevent rope damage.
What is the expected longevity of the gate and its spring action?
The wire is the strongest part of the carabiner; the body will fail
before the wire gate will break. With a 25 kN closed gate Three Sigma
rating, the HotWire is among the strongest carabiners ever designed. To
test the integrity of the gate-spring action, we measured the gate force
of several samples of HotWires on our Carabiner Test Machine, then cycled
them on a fatigue test station which repeatedly opens and closes the
gates. After testing the samples with more than 300,000 cycles, we
remeasured the samples on the Carabiner Test Machine, which showed no
measurable change in gate-spring action or failure strength. The wire
gate's action will not wear out or weaken under normal use.
How effectively do HotWires prevent "whiplash" (carabiner gate oscillation)?
Whiplash is a sudden opening of a rope-carrying carabiner's gate in
reaction to a sudden force, such as when the biner is loaded by a fall,
or if it slams against the rock. On very rare occasions, this
instantaneous opening of the gate can result in carabiner failure, if the
biner is loaded at the precise moment the gate is open. The low mass of
the HotWire's gate helps to eliminate whiplash, as does its stiff gate
action. By using high speed photography, we observed how HotWire gates
reacted to sudden forces. The wire gates proved to be much less
susceptible to whiplash movement, where conventional biner gates
oscillated substantially more.
Can HotWires be used on both ends of a quickdraw?
Yes. The gate's flat surface makes clipping the rope into the HotWire as
easy as clipping a bent-gate biner. The HotWire can also be used for
clipping bolts, pro, anchors (doubled up and opposed of course) and for
all other general carabiner uses. Any biner which clips easily can also
be prone to unclipping; take precautions to prevent situations where this
could happen.
If your quickdraws have HotWires on both ends, we recommend that you use one end exclusively for clipping the rope and use the other end just for
clipping bolts. Why? As you've probably noticed, on regular quickdraws
with one bent gate and one straight gate biner, the straight-gate biner
gets worn on the inside from the bolt hanger. Everyday wear on the
inside of the biner body does not affect strength, but can create small
edges that could damage a rope. This applies to HotWire carabiners too.
If your quickdraws have HotWires on the top and bottom, we suggest you
mark your draws to identify which is the bolt-clipping biner.
Are HotWires just for sport climbing?
HotWires are for ALL types of climbing: long gear routes, sport climbs,
ice, mountaineering, aid. The HotWire's testing has included extensive
field use with both prototype and production models. Their performance
out of the lab has been nothing short of excellent across the spectrum of
climbing environs. Alpine climbers appreciated a super-strong,
lightweight biner that wouldn't freeze up due to its one piece
gate/spring mechanism. HotWires were also popular with aid climbers and
long-route aficionados for their versatility and minimal
weight.
Are there any applications in which HotWires should not be used?
We do not recommend that you use HotWires to make a carabiner-brake
rappel. You won't break the biner, but you could bend the gate,
rendering the biner unusable in the future.
Does taping around the gate improve the biner?
We don't recommend that you tape the gate. Wrapping tape around the gate wire restricts the spring action of the gate. The two legs of the wire
work independently against each other to act like a spring; when they
cannot move freely, the gate action is compromised.
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