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Shingoshi
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Did you ever hear of Einstein's Refrigerator?
I hadn't until this weekend. I am wondering what kind of modifications can be made to this type of refrigeration cycle that would allow it to produce
very deep temperatures. Like -100*Celsius.
What chemicals could be substituted to reach the coldest temps? What if this were used in conjunction with a power source? How much would this
refrigeration cycle increase the performance of other technologies when combined?
Shingoshi
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12AX7
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Namely, the Einstein-Szilard absorption cycle.
It depends on a gaseous/dissolved medium and a solvent which can dissolve a large amount of said medium; these are usually ammonia and water
respectively. I don't see why other media couldn't be used, but efficiency probably suffers (NH3(aq) <--> NH3(g) has a high delta H).
You would probably need several stages to reach such a temperature, which is a lot like stacking peltier devices: the heat goes up exponentially.
Well, it does anyway, but with a lot of stages and a *really* bad efficiency, well, you do the math...
Tim
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Shingoshi
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Szilard Lizard...
| Quote: | Originally posted by 12AX7
Namely, the Einstein-Szilard absorption cycle.
It depends on a gaseous/dissolved medium and a solvent which can dissolve a large amount of said medium; these are usually ammonia and water
respectively. I don't see why other media couldn't be used, but efficiency probably suffers (NH3(aq) <--> NH3(g) has a high delta H).
You would probably need several stages to reach such a temperature, which is a lot like stacking peltier devices: the heat goes up exponentially.
Well, it does anyway, but with a lot of stages and a *really* bad efficiency, well, you do the math...
Tim |
Yeah. Szilard got the worst end of that deal. Maybe? Because how likely would it have been accepted, if Albert hadn't been involved?
Ok. But there was also Butane involved in this as well. Why couldn't another gas, with which the ammonia would entail, be used instead off Butane? And
why not Ethanol instead of water, or an azeotropic mixture of both, or others.
And stacking is the technique for supercooling anyway. It's not a question of efficiency, as much as is there any other way it can be done. I don't
think any method is capable of reaching those levels without staging. The question is, how much can you reduce the number of stages?
Shingoshi
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not_important
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The water serves to separate the ammonia and butane, using ethanol would actually reduce the efficiency as it would reduce the solubility of ammonia
and increase the solubility of butane in that phase, and increase the vapour pressure of the 3rd (or 4th) substance in the system.
The problem obtaining low temperatures with this or related designs is the need to have a gas at the low temperature that can be absorbed in a liquid,
and a second gas that boils at the low temperature under reduced partial pressure and liquefies at the same total pressure (but higher temperature)
and does not dissolve in the 1st liquid.
http://www.me.gatech.edu/energy/andy_phd/index.html
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Sauron
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Ever heard of Szilard's bathtub?
Leo Szilard was a fine physicist and one of the small group who persuaded Enstein to put his name to the letter to FDR proposing the Manhattan
Project.
But he was eccentric as hell. When General Leslie Groves visited him in Chicago to discuss the practicability of designing and building an atomic
bomb, Szilard gave Grove an audience while lounging in his bathtub.
Szilard expected to have a senior position on the project but Groves regarded him as a crackpot and although Szilard was a key figure at the
theoretical side of the Project in Chicago, he was never a central player at Los Alamos.
Szilard further alienated Groves by being one of the key proponents of the demonstration of the bomb to the Japanese. Once the war in Europe was over,
Szilard's main motivation for the bomb development was removed and his ethical scruples about the use of the weapon against Japan surfaced. However,
Szilard was unsuccesful in this second attempted intercession with the President, the push to defeat Japan was on and the multi-billion dollar
investment in the Project demanded a return. In August 1945 we got our money's worth.
May that be the end of it.
[Edited on 21-4-2008 by Sauron]
Sic gorgeamus a los subjectatus nunc.
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Shingoshi
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What do they call this, Thimblerig...
| Quote: | Originally posted by not_important
The water serves to separate the ammonia and butane, using ethanol would actually reduce the efficiency as it would reduce the solubility of ammonia
and increase the solubility of butane in that phase, and increase the vapour pressure of the 3rd (or 4th) substance in the system.
The problem obtaining low temperatures with this or related designs is the need to have a gas at the low temperature that can be absorbed in a liquid,
and a second gas that boils at the low temperature under reduced partial pressure and liquefies at the same total pressure (but higher temperature)
and does not dissolve in the 1st liquid.
http://www.me.gatech.edu/energy/andy_phd/index.html |
There's a different name that I can't think of. But it's the same game. Switching something around to confuse the unwitting.
Ok. Are there no other three substances that perform in a similar manner as these, which may function better? But I guess if there were, Albert would
have used them, huh?
Shingoshi
[Edited on 2008.4.21 by Shingoshi]
This is the guy who I read and turned me on to this.
[Edited on 2008.4.21 by Shingoshi]
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not_important
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Ammonia and water seem to be the best pair, several of the lighter alkanes and haloalkanes have been used, and there is the related device which uses
NH3-H2O and hydrogen as a non-condensible gas.
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Shingoshi
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What if you didn't have to introduce heat??
| Quote: | Originally posted by not_important
Ammonia and water seem to be the best pair, several of the lighter alkanes and haloalkanes have been used, and there is the related device which uses
NH3-H2O and hydrogen as a non-condensible gas. |
What if the means for lowering the pressure of the Butane (or any other gas) was caused (or enhanced) by cavitation induced by ultrasonics?
Shingoshi
The thing that really caught my attention when I read about this the first time, was that Andrew actually froze the water the first time he tried it.
He had to change things to lower the efficiency of the system to keep it from freezing. So I imagine this could easily be used as a freezer, and not
just a refrigerator.
[Edited on 2008.4.21 by Shingoshi]
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Pulverulescent
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| Quote: | Originally posted by Sauron
Groves regarded him as a crackpot |
IIRC, Groves called the Los Alamos community, "The Greatest Collection of Crackpots in One Place the World has Ever Seen"!
Or words to that effect!
P
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Shingoshi
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Sounds like my kind of people!!
| Quote: | Originally posted by Pulverulescent
| Quote: | Originally posted by Sauron
Groves regarded him as a crackpot |
IIRC, Groves called the Los Alamos community, "The Greatest Collection of Crackpots in One Place the World has Ever Seen"!
Or words to that effect!
P |
Sounds like I would have been perfectly at home among them.
Shingoshi
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Pulverulescent
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Yes, Shingoshi, we'd (most all) be on the list, if he were still around!
P
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Sauron
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Groves was an Army engineer whose experience was in the management of megaprojects, his last assignment prior to Manhattan was the construction of the
Pentagon (as a colonel.) He had little affinity for academics and he had something of a reputation as a martinet. But he knew how to get things done,
and Manhattan had top priority for logistics, supplies were tight in wartime. Remember, we aren't just talking LANL but Oak Ridge which Groves built,
and Hanford, and the Chicago bunch, and the metallurgy dept at MIT (now a corporation called Nuclear Metals Inc.) etc. Los Alamos was the integration
team. They had to design and build the thing while Hanford and ORNL were making the fissiles, and they had a 19 month deadline.
In keeping everything on track Groves antagonized a great many of his fellow military leaders, quite a few of them senior to him (he was only a
brigadier.) After V-J Day the recriminations set in. With the belaureled combat generals returning home it was very clear that Groves could not
expect promotion and a position of anything like the kind of nearly untrammeled authority he had enjoyed as commander of the Manhattan District, Corps
of Engineers. There were too many competitors for such positions and too many people had their knives out for Groves. So he resigned his commission,
eventually taking an executive position with a major Defense contractor.
The military lost control of the nuclear program, Truman created the Atomic Energy Commission to control it. There was a very interesting infight in
the physics community, the eastern physics establishment was very jealous of the hegemony of the Berkeley mob (Lawrence, Oppenheimer, etc.) and
lobbied vigorously for their slice of the pie. The upshot was that Brookhaven was created, but the boys from the UC Radlab were not to be toppled.
Lawrence's close associate Glenn T.Seaborg became the chairman of the AEC.
Oppenheimer's fall from grace was not much less severe than Groves' own. Oppie antagonized many inside and outside of his scientific community by
opposing the development of Teller's 'super', which we now know as the H-bomb, and eventually, in the McCarthy era a few years later, Oppie's left
wing associations which Groves had sat on during the war, came back to haunt him and he was stripped of his security clearances. To be fair,
Oppenheimer was unlikely to ever have been a member of the Communist Party. But his brother Frank was, as was his girlfriend - well there was a lot of
that going around during the Depression, wasn't there? Nor did Oppie have anything to do with the succesful Soviet espionage program against
Manhattan.
Sic gorgeamus a los subjectatus nunc.
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Shingoshi
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I asked this question before, without response...
What if the means for lowering the pressure of the Butane (or any other gas) was caused (or enhanced) by the cavitation induced by ultrasonics?
So maybe I should explain myself. What I'm asking is, whether or not the evacuation of any gas in a fluid suspension can be accelerated by the
introduction of ultrasonic cavitation? Since the cavitation serves to lower the pressure of the fluid, wouldn't that lower pressure lead to a more
aggressive evaporation of the gas, before the fluid itself would do so? The purpose, is to reduce the amount of heat which must be introduced into the
refrigeration system.
Shingoshi
[Edited on 2008.4.22 by Shingoshi]
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not_important
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As cavitation cause low pressure regions and the formation of bubbles, it will get vapour coming sooner. But it doesn't change the partial pressure
above the liquid, nor the average pressure in the fluid, so the same equilibrium is reached - the same percentage of the volatile component in the
vapour as without cavitation. That volatile component is what is removing the heat. Note that the fluid need not be boiling to evaporate and remove
heat, the old trick of freezing a little water by evaporating ether by blowing air across it happens well below ether's boiling point.
Also note that cavitation injects energy into the system that you are attempting to use to remove energy from the cooling target.
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Shingoshi
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I just came across this...
I thought I would post this here for inclusion in our discussion:
http://en.wikipedia.org/wiki/Adiabatic_demagnetization
Another thing which has me curious, is how practical is it to use a 4-component refrigerant system. I'm thinking specifically of using, Water,
Ammonia, Butane and Hydrogen. The Water, Ammonia and Butane has already been discussed in the Einstein Refrigeration cycle. We've also mentioned the
old technique of Ammonia and Hydrogen, from the old Ammonia refrigerators.
So I'm wondering, if a system had a very low pressure of Hydrogen, with only a moderately higher pressure of Butane, how would the evaporation of
Ammonia be enhanced by the now even cooler temperatures of Butane expanding in Hydrogen? Basically, I'm speaking of combining both of the
aforementioned refrigeration technologies into a single system. Please give your comments concerning this.
Shingoshi
BTW. The Attachment's Browse button really needs to be moved, preferably above the message box. I (and likely others as well) have frequently pressed
the Browse button inadvertently. It's something that doesn't need to occur at all.
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not_important
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In regards to magnetocaloric refrigeration:
| Quote: | The first milestone in magnetic cooling has been achieved. Between 5 and 10 degrees of cooling – this was the success criteria for the first
milestone in a project involving magnetic cooling at Risø National Laboratory – Technical University of Denmark (DTU). And the figure is currently
at 8.7°C – this means that a refrigerator at room temperature (20°C) can be cooled to almost 11°C.
...
More than DKK 21 million in new funding has made it possible to appoint three PhD students this year to work on the MagCool project,
and two more PhD students are to be appointed this autumn. Christian Bahl will also be joined by another two postdoctoral students in 2009.
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Just a little effort, in terms of money and highly educated manpower, to throw at a process that for room temperature purposes currently tops out at
around 25 C difference and a few tens of watts of cooling. On top of that you need gadolinium metal based alloys, not something that easy to fab in
your toaster-oven.
Right now you'd do a lot better to use thermoelectric cooling, unless you have a half dozen grade and PHD types stashed away in your attic, and a
large bank account.
I'm too sleepy to comment much on the 4 component idea, save to say that the cooling rate is determined in part by the amount of coolant evaporating;
reducing the pressure means smaller amounts evaporating, and a lower heat flux (fewer watts) of cooling per given volume. The ammonia evaporation is
done pretty much outside of the influence of the other gases.
What is it you hope to achieve with this variation?
And if you use 'Quick Reply' there is no Browse button. I myself find it easy to press 'cancel'.
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jimwig
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all this reminds me of icy balls. no not to do with ice fishing. a no moving parts method refrigeration. moving heat is name of the game. so this
device both heats and cools. can't have one without the other.
http://en.wikipedia.org/wiki/Icy_Ball
there's some really good pages that don't want you to buy something but i have lost them to time. oh well
sure there is lots of stuff on google etc
craZy jiM wGGns
--packrat, professional bum. -- once just tired
now REtired.
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Shingoshi
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Raising the refrigeration efficiency by Einstein cycle.
Raising the refrigeration efficiency by Einstein cycle.
| Quote: | Originally posted by jimwig
all this reminds me of icy balls. no not to do with ice fishing. a no moving parts method refrigeration. moving heat is name of the game. so this
device both heats and cools. can't have one without the other.
http://en.wikipedia.org/wiki/Icy_Ball
there's some really good pages that don't want you to buy something but i have lost them to time. oh well
sure there is lots of stuff on google etc |
Thank you for your contribution! I checked out that link for Icy Balls, and found myself on a journey of multiple paths. One of those paths took me
here. http://www.freepatentsonline.com/3817046.html
As I was asked above why would I consider multi-component refrigeration, I hope this explains. I am interested in using a multi-stage refrigeration
system. The benefit is much lower temperatures than can be achieved in a single stage. Much like the multiple stages of a turbojet's compressor fans,
the more stages, the more compression achieved. I had already thought about using multiple compressors in a staged refrigeration system. But I would
like to augment the efficiency of the complete system, by having each of the different components benefiting from the negatives of the others.
For instance, I don't know how much heat is generated by the compressors in a standard electric refrigerator. Nor do I know how much heat must be
applied to an Einstein or Ammonia Refrigerator. But since at every stage of compression, heat is generated that must be then dissipated, I think it
only wise to use that otherwise wasted heat to function in an ammonia refrigeration cycle. Instead of using a radiator as a condenser, it could easily
be used to drive the evaporation of ammonia (or some other gas with the same purpose). I think it would simply have to be ensured, that the compressed
gas from one stage, being used to evaporate another gas in a secondary stage, not be allowed to cool below such a temperature as to remove heat from
the secondary solution.
So, in a system which uses (multiple) electric compressors, the compressed (and now heated) gas would heat an ammonia/water solution. That solution
then boiling off it's ammonia would become the coolant (by expansion) to further lower the temperature of the gas which had just heated it. Having
multiple stages would only ensure that a higher level of heat is provided to the mixture of the ammonia/water. Essentially, the Einstein Refrigerator
would be used as the condenser for our electrically driven system, raising the efficiency of it, without requiring an additional heat source to drive
the Einstein system.
Just for more fun, take a look at this!
http://www.electricitybook.com/magnetism/
Xavian-Anderson Macpherson
Shingoshi
[Edited on 2008.4.25 by Shingoshi]
[Edited on 2008.4.25 by Shingoshi]
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Shingoshi
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If they can do a single stage this small...
There really isn't any reason why this procedure, whatever it is, can't be used in the system I want to build. My target temperatures (-100 *C) aren't
unattainable, especially when you consider that I'm only using this to cool 4-cpus on my motherboard. If the capacity of the cooling system, is
determined by the volumetric space to be cooled, 4-cpus will present no problem at all. But given the fact that I've seen this, and another article
elsewhere posting this temperature, choosing the right gas (methane, neon?) should give even lower values in a cascaded system.
http://freezerlink.com/ultra_cold.htm
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not_important
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One working gas needs to be a liquid at the low temperature, but have a reasonable vapour pressure there. Then you need another gas, which stays a
gas at the lowest temperature; those two gases must have greatly different solubilities in a 3rd component which is a liquid of fairly low vapour
pressure at a higher temperature. The gas soluble in the liquid must have a steep solubility vs temperature curve.
The freezerlink gear is standard design compressor gear. It uses hydrofluorcarbons for its working fluid, chosen for their boiling points.
There's no reason the Einstein-Szilard is any more efficient than compressor systems; it lacks mechanical moving parts and uses simple heat to make it
work, but absorption refrigeration generally isn't terribly efficient. I believe the E-S units have a COP around 0.2 which is not bad for absorption
but that's at the specific temperatures for home refrigeration.
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Shingoshi
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I think you missed my point...
| Quote: | Originally posted by not_important
One working gas needs to be a liquid at the low temperature, but have a reasonable vapour pressure there. Then you need another gas, which stays a
gas at the lowest temperature; those two gases must have greatly different solubilities in a 3rd component which is a liquid of fairly low vapour
pressure at a higher temperature. The gas soluble in the liquid must have a steep solubility vs temperature curve.
The freezerlink gear is standard design compressor gear. It uses hydrofluorcarbons for its working fluid, chosen for their boiling points.
There's no reason the Einstein-Szilard is any more efficient than compressor systems; it lacks mechanical moving parts and uses simple heat to make it
work, but absorption refrigeration generally isn't terribly efficient. I believe the E-S units have a COP around 0.2 which is not bad for absorption
but that's at the specific temperatures for home refrigeration. |
But then again, I may not have been clear enough. I was simply attempting to say, that if the electric compressor system is going to produce heat
which must then be removed, it just seems to make sense, to use that heat (if there's enough of it) to either augment or directly facilitate the
operation of the E-S refrigeration system. Especially since (at least) the ammonia (and possibly other gases) could be common between both.
I hope that's more clear than before. And part of my thinking was based on another webpage I came across for (pressurizing) scuba tanks. The point
there being, that if you cascade the filling mechanism (in that case, four reserve tanks in series) used to fill the scuba tanks, the time required to
do so is substantially reduced. And since we're still talking about compressed gases, it applies to my situation as well as theirs. And the point is
then, that even more heat is raised by using cascaded compressors. And you're much better off (by higher heat transfer) using another fluid in a heat
exchanger to cool the working gas, rather than wasting that heat being passed off to the environment.
The only question that remains now, is how much heat is required to operate an E-S refrigerator? Here's an analogy which might help. I'm thinking of
using the E-S in much the same way as turbochargers are used to recover energy (which would be otherwise wasted) from the engine's exhaust heat to
raise the efficiency of the engine. And continuing with the turbocharger analogy, they too are often cascaded in series, referred to as tandem turbos.
Shingoshi
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tumadre
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I understand what you're saying, but my limited knowledge about COP tells me that increasing the temperature of the condenser on the electric side
will net an overall increase in energy required because the cop of the E-S cooling is less than the compressive type.
If high grade heat is available at the compressor output, then you should cascade multiple compressors with intercoolers in between then resulting in
a reduction in work with a net increase in COP.
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Shingoshi
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That's one COLD MF!!
| Quote: | Originally posted by tumadre
I understand what you're saying, but my limited knowledge about COP tells me that increasing the temperature of the condenser on the electric side
will net an overall increase in energy required because the cop of the E-S cooling is less than the compressive type.
If high grade heat is available at the compressor output, then you should cascade multiple compressors with intercoolers in between then resulting in
a reduction in work with a net increase in COP. |
That's why I want to use E-S as the interstage intercoolers for the cascaded compressors. Not only would they act as coolers (by means of heat
exchangers), they would/could also be used to cool the compressor bodies directly. Again, this would increase the performance of the compressors, by
reducing the heat they operate at. Which in turn would increase the capacity and pressure of the gases passed through them. Such a system might
possibly run on helium or nitrogen as the working gases in the compressors. How cold can we get!! 
Shingoshi
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Shingoshi
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Has anyone ever seen or heard of these before??
Vortex Tubes??
If this thing is real, it presents rather tremendous possibilities. Think of using the compressed gases as the driving force. And they produce BOTH
cold and heat simultaneously. Wow. 
http://www.arizonavortex.com/vortex-tube/
Shingoshi
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BromicAcid
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Shingoshi, searching 'vortext tube' in the normal forum search engine brings up the pre-existing thread on the subject:
http://www.sciencemadness.org/talk/viewthread.php?tid=4907
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